r3215 - in trunk/varnish-cache/lib: . libjemalloc

tfheen at projects.linpro.no tfheen at projects.linpro.no
Wed Sep 24 14:41:27 CEST 2008


Author: tfheen
Date: 2008-09-24 14:41:27 +0200 (Wed, 24 Sep 2008)
New Revision: 3215

Added:
   trunk/varnish-cache/lib/libjemalloc/
   trunk/varnish-cache/lib/libjemalloc/Makefile
   trunk/varnish-cache/lib/libjemalloc/README
   trunk/varnish-cache/lib/libjemalloc/jemalloc_linux.c
   trunk/varnish-cache/lib/libjemalloc/malloc.3
   trunk/varnish-cache/lib/libjemalloc/malloc.c
   trunk/varnish-cache/lib/libjemalloc/rb.h
Log:
Import jemalloc


Added: trunk/varnish-cache/lib/libjemalloc/Makefile
===================================================================
--- trunk/varnish-cache/lib/libjemalloc/Makefile	                        (rev 0)
+++ trunk/varnish-cache/lib/libjemalloc/Makefile	2008-09-24 12:41:27 UTC (rev 3215)
@@ -0,0 +1,23 @@
+CFLAGS := -O3 -g
+# See source code comments to avoid memory leaks when enabling MALLOC_MAG.
+#CPPFLAGS := -DMALLOC_PRODUCTION -DMALLOC_MAG
+CPPFLAGS := -DMALLOC_PRODUCTION
+
+all: libjemalloc.so.0 libjemalloc_mt.so.0
+
+jemalloc_linux_mt.o: jemalloc_linux.c
+	gcc $(CFLAGS) -c -DPIC -fPIC $(CPPFLAGS) -D__isthreaded=true -o $@ $+
+
+jemalloc_linux.o: jemalloc_linux.c
+	gcc $(CFLAGS) -c -DPIC -fPIC $(CPPFLAGS) -D__isthreaded=false -o $@ $+
+
+libjemalloc_mt.so.0: jemalloc_linux_mt.o
+	gcc -shared -lpthread -o $@ $+
+	ln -sf $@ libjemalloc_mt.so
+
+libjemalloc.so.0: jemalloc_linux.o
+	gcc -shared -lpthread -o $@ $+
+	ln -sf $@ libjemalloc.so
+
+clean:
+	rm -f *.o *.so.0 *.so

Added: trunk/varnish-cache/lib/libjemalloc/README
===================================================================
--- trunk/varnish-cache/lib/libjemalloc/README	                        (rev 0)
+++ trunk/varnish-cache/lib/libjemalloc/README	2008-09-24 12:41:27 UTC (rev 3215)
@@ -0,0 +1,55 @@
+This is a minimal-effort stand-alone jemalloc distribution for Linux.  The main
+rough spots are:
+
+* __isthreaded must be hard-coded, since the pthreads library really needs to
+  be involved in order to toggle it at run time.  Therefore, this distribution
+  builds two separate libraries:
+
+  + libjemalloc_mt.so.0 : Use for multi-threaded applications.
+  + libjemalloc.so.0 : Use for single-threaded applications.
+
+  Both libraries link against libpthread, though with a bit more code hacking,
+  this dependency could be removed for the single-threaded version.
+
+* MALLOC_MAG (thread-specific caching, using magazines) is disabled, because
+  special effort is required to avoid memory leaks when it is enabled.  To make
+  cleanup automatic, we would need help from the pthreads library.  If you
+  enable MALLOC_MAG, be sure to call _malloc_thread_cleanup() in each thread
+  just before it exits.
+
+* The code that determines the number of CPUs is sketchy.  The trouble is that
+  we must avoid any memory allocation during early initialization.
+
+In order to build:
+
+    make
+
+This generates two shared libraries, which you can either link against, or
+pre-load.
+
+Linking and running, where /path/to is the path to libjemalloc (-lpthread
+required even for libjemalloc.so):
+
+    gcc app.o -o app -L/path/to -ljemalloc_mt -lpthread
+    LD_LIBRARY_PATH=/path/to app
+
+Pre-loading:
+
+    LD_PRELOAD=/path/to/libjemalloc_mt.so.0 app
+
+jemalloc has a lot of run-time tuning options.  See the man page for details:
+
+    nroff -man malloc.3 | less
+
+In particular, take a look at the B, F, and N options.  If you enable
+MALLOC_MAG, look at the G and R options.
+
+If your application is crashing, or performance seems to be lacking, enable
+assertions and statistics gathering by removing MALLOC_PRODUCTION from CPPFLAGS
+in the Makefile.  In order to print a statistics summary at program exit, run
+your application like:
+
+    LD_PRELOAD=/path/to/libjemalloc_mt.so.0 MALLOC_OPTIONS=P app
+
+Please contact Jason Evans <jasone at canonware.com> with questions, comments, bug
+reports, etc.

Added: trunk/varnish-cache/lib/libjemalloc/jemalloc_linux.c
===================================================================
--- trunk/varnish-cache/lib/libjemalloc/jemalloc_linux.c	                        (rev 0)
+++ trunk/varnish-cache/lib/libjemalloc/jemalloc_linux.c	2008-09-24 12:41:27 UTC (rev 3215)
@@ -0,0 +1,5670 @@
+/*-
+ * Copyright (C) 2006-2008 Jason Evans <jasone at FreeBSD.org>.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice(s), this list of conditions and the following disclaimer as
+ *    the first lines of this file unmodified other than the possible
+ *    addition of one or more copyright notices.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice(s), this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *******************************************************************************
+ *
+ * This allocator implementation is designed to provide scalable performance
+ * for multi-threaded programs on multi-processor systems.  The following
+ * features are included for this purpose:
+ *
+ *   + Multiple arenas are used if there are multiple CPUs, which reduces lock
+ *     contention and cache sloshing.
+ *
+ *   + Thread-specific caching is used if there are multiple threads, which
+ *     reduces the amount of locking.
+ *
+ *   + Cache line sharing between arenas is avoided for internal data
+ *     structures.
+ *
+ *   + Memory is managed in chunks and runs (chunks can be split into runs),
+ *     rather than as individual pages.  This provides a constant-time
+ *     mechanism for associating allocations with particular arenas.
+ *
+ * Allocation requests are rounded up to the nearest size class, and no record
+ * of the original request size is maintained.  Allocations are broken into
+ * categories according to size class.  Assuming runtime defaults, 4 kB pages
+ * and a 16 byte quantum on a 32-bit system, the size classes in each category
+ * are as follows:
+ *
+ *   |=======================================|
+ *   | Category | Subcategory      |    Size |
+ *   |=======================================|
+ *   | Small    | Tiny             |       2 |
+ *   |          |                  |       4 |
+ *   |          |                  |       8 |
+ *   |          |------------------+---------|
+ *   |          | Quantum-spaced   |      16 |
+ *   |          |                  |      32 |
+ *   |          |                  |      48 |
+ *   |          |                  |     ... |
+ *   |          |                  |      96 |
+ *   |          |                  |     112 |
+ *   |          |                  |     128 |
+ *   |          |------------------+---------|
+ *   |          | Cacheline-spaced |     192 |
+ *   |          |                  |     256 |
+ *   |          |                  |     320 |
+ *   |          |                  |     384 |
+ *   |          |                  |     448 |
+ *   |          |                  |     512 |
+ *   |          |------------------+---------|
+ *   |          | Sub-page         |     760 |
+ *   |          |                  |    1024 |
+ *   |          |                  |    1280 |
+ *   |          |                  |     ... |
+ *   |          |                  |    3328 |
+ *   |          |                  |    3584 |
+ *   |          |                  |    3840 |
+ *   |=======================================|
+ *   | Large                       |    4 kB |
+ *   |                             |    8 kB |
+ *   |                             |   12 kB |
+ *   |                             |     ... |
+ *   |                             | 1012 kB |
+ *   |                             | 1016 kB |
+ *   |                             | 1020 kB |
+ *   |=======================================|
+ *   | Huge                        |    1 MB |
+ *   |                             |    2 MB |
+ *   |                             |    3 MB |
+ *   |                             |     ... |
+ *   |=======================================|
+ *
+ * A different mechanism is used for each category:
+ *
+ *   Small : Each size class is segregated into its own set of runs.  Each run
+ *           maintains a bitmap of which regions are free/allocated.
+ *
+ *   Large : Each allocation is backed by a dedicated run.  Metadata are stored
+ *           in the associated arena chunk header maps.
+ *
+ *   Huge : Each allocation is backed by a dedicated contiguous set of chunks.
+ *          Metadata are stored in a separate red-black tree.
+ *
+ *******************************************************************************
+ */
+
+/*
+ * Set to false if single-threaded.  Even better, rip out all of the code that
+ * doesn't get used if __isthreaded is false, so that libpthread isn't
+ * necessary.
+ */
+#ifndef __isthreaded
+#  define __isthreaded true
+#endif
+
+/*
+ * MALLOC_PRODUCTION disables assertions and statistics gathering.  It also
+ * defaults the A and J runtime options to off.  These settings are appropriate
+ * for production systems.
+ */
+/* #define	MALLOC_PRODUCTION */
+
+#ifndef MALLOC_PRODUCTION
+   /*
+    * MALLOC_DEBUG enables assertions and other sanity checks, and disables
+    * inline functions.
+    */
+#  define MALLOC_DEBUG
+
+   /* MALLOC_STATS enables statistics calculation. */
+#  define MALLOC_STATS
+#endif
+
+/*
+ * MALLOC_TINY enables support for tiny objects, which are smaller than one
+ * quantum.
+ */
+#define	MALLOC_TINY
+
+/*
+ * MALLOC_MAG enables a magazine-based thread-specific caching layer for small
+ * objects.  This makes it possible to allocate/deallocate objects without any
+ * locking when the cache is in the steady state.
+ *
+ * If MALLOC_MAG is enabled, make sure that _malloc_thread_cleanup() is called
+ * by each thread just before it exits.
+ */
+/* #define	MALLOC_MAG */
+
+/*
+ * MALLOC_BALANCE enables monitoring of arena lock contention and dynamically
+ * re-balances arena load if exponentially averaged contention exceeds a
+ * certain threshold.
+ */
+#define	MALLOC_BALANCE
+
+/*
+ * MALLOC_DSS enables use of sbrk(2) to allocate chunks from the data storage
+ * segment (DSS).  In an ideal world, this functionality would be completely
+ * unnecessary, but we are burdened by history and the lack of resource limits
+ * for anonymous mapped memory.
+ */
+/* #define	MALLOC_DSS */
+
+#define	_GNU_SOURCE /* For mremap(2). */
+#define	issetugid() 0
+#define	__DECONST(type, var)	((type)(uintptr_t)(const void *)(var))
+
+/* __FBSDID("$FreeBSD: head/lib/libc/stdlib/malloc.c 182225 2008-08-27 02:00:53Z jasone $"); */
+
+#include <sys/mman.h>
+#include <sys/param.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#include <sys/uio.h>
+
+#include <errno.h>
+#include <limits.h>
+#ifndef SIZE_T_MAX
+#  define SIZE_T_MAX	SIZE_MAX
+#endif
+#include <pthread.h>
+#include <sched.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <pthread.h>
+
+#include "rb.h"
+
+#ifdef MALLOC_DEBUG
+   /* Disable inlining to make debugging easier. */
+#  define inline
+#endif
+
+/* Size of stack-allocated buffer passed to strerror_r(). */
+#define	STRERROR_BUF		64
+
+/*
+ * The const_size2bin table is sized according to PAGESIZE_2POW, but for
+ * correctness reasons, we never assume that
+ * (pagesize == (1U << * PAGESIZE_2POW)).
+ *
+ * Minimum alignment of allocations is 2^QUANTUM_2POW bytes.
+ */
+#ifdef __i386__
+#  define PAGESIZE_2POW		12
+#  define QUANTUM_2POW		4
+#  define SIZEOF_PTR_2POW	2
+#  define CPU_SPINWAIT		__asm__ volatile("pause")
+#endif
+#ifdef __ia64__
+#  define PAGESIZE_2POW		12
+#  define QUANTUM_2POW		4
+#  define SIZEOF_PTR_2POW	3
+#endif
+#ifdef __alpha__
+#  define PAGESIZE_2POW		13
+#  define QUANTUM_2POW		4
+#  define SIZEOF_PTR_2POW	3
+#  define NO_TLS
+#endif
+#ifdef __sparc64__
+#  define PAGESIZE_2POW		13
+#  define QUANTUM_2POW		4
+#  define SIZEOF_PTR_2POW	3
+#  define NO_TLS
+#endif
+#ifdef __amd64__
+#  define PAGESIZE_2POW		12
+#  define QUANTUM_2POW		4
+#  define SIZEOF_PTR_2POW	3
+#  define CPU_SPINWAIT		__asm__ volatile("pause")
+#endif
+#ifdef __arm__
+#  define PAGESIZE_2POW		12
+#  define QUANTUM_2POW		3
+#  define SIZEOF_PTR_2POW	2
+#  define NO_TLS
+#endif
+#ifdef __mips__
+#  define PAGESIZE_2POW		12
+#  define QUANTUM_2POW		3
+#  define SIZEOF_PTR_2POW	2
+#  define NO_TLS
+#endif
+#ifdef __powerpc__
+#  define PAGESIZE_2POW		12
+#  define QUANTUM_2POW		4
+#  define SIZEOF_PTR_2POW	2
+#endif
+
+#define	QUANTUM			((size_t)(1U << QUANTUM_2POW))
+#define	QUANTUM_MASK		(QUANTUM - 1)
+
+#define	SIZEOF_PTR		(1U << SIZEOF_PTR_2POW)
+
+/* sizeof(int) == (1U << SIZEOF_INT_2POW). */
+#ifndef SIZEOF_INT_2POW
+#  define SIZEOF_INT_2POW	2
+#endif
+
+/* We can't use TLS in non-PIC programs, since TLS relies on loader magic. */
+#if (!defined(PIC) && !defined(NO_TLS))
+#  define NO_TLS
+#endif
+
+#ifdef NO_TLS
+   /* MALLOC_MAG requires TLS. */
+#  ifdef MALLOC_MAG
+#    undef MALLOC_MAG
+#  endif
+   /* MALLOC_BALANCE requires TLS. */
+#  ifdef MALLOC_BALANCE
+#    undef MALLOC_BALANCE
+#  endif
+#endif
+
+/*
+ * Size and alignment of memory chunks that are allocated by the OS's virtual
+ * memory system.
+ */
+#define	CHUNK_2POW_DEFAULT	20
+
+/* Maximum number of dirty pages per arena. */
+#define	DIRTY_MAX_DEFAULT	(1U << 9)
+
+/*
+ * Maximum size of L1 cache line.  This is used to avoid cache line aliasing.
+ * In addition, this controls the spacing of cacheline-spaced size classes.
+ */
+#define	CACHELINE_2POW		6
+#define	CACHELINE		((size_t)(1U << CACHELINE_2POW))
+#define	CACHELINE_MASK		(CACHELINE - 1)
+
+/*
+ * Subpages are an artificially designated partitioning of pages.  Their only
+ * purpose is to support subpage-spaced size classes.
+ *
+ * There must be at least 4 subpages per page, due to the way size classes are
+ * handled.
+ */
+#define	SUBPAGE_2POW		8
+#define	SUBPAGE			((size_t)(1U << SUBPAGE_2POW))
+#define	SUBPAGE_MASK		(SUBPAGE - 1)
+
+#ifdef MALLOC_TINY
+   /* Smallest size class to support. */
+#  define TINY_MIN_2POW		1
+#endif
+
+/*
+ * Maximum size class that is a multiple of the quantum, but not (necessarily)
+ * a power of 2.  Above this size, allocations are rounded up to the nearest
+ * power of 2.
+ */
+#define	QSPACE_MAX_2POW_DEFAULT	7
+
+/*
+ * Maximum size class that is a multiple of the cacheline, but not (necessarily)
+ * a power of 2.  Above this size, allocations are rounded up to the nearest
+ * power of 2.
+ */
+#define	CSPACE_MAX_2POW_DEFAULT	9
+
+/*
+ * RUN_MAX_OVRHD indicates maximum desired run header overhead.  Runs are sized
+ * as small as possible such that this setting is still honored, without
+ * violating other constraints.  The goal is to make runs as small as possible
+ * without exceeding a per run external fragmentation threshold.
+ *
+ * We use binary fixed point math for overhead computations, where the binary
+ * point is implicitly RUN_BFP bits to the left.
+ *
+ * Note that it is possible to set RUN_MAX_OVRHD low enough that it cannot be
+ * honored for some/all object sizes, since there is one bit of header overhead
+ * per object (plus a constant).  This constraint is relaxed (ignored) for runs
+ * that are so small that the per-region overhead is greater than:
+ *
+ *   (RUN_MAX_OVRHD / (reg_size << (3+RUN_BFP))
+ */
+#define	RUN_BFP			12
+/*                                    \/   Implicit binary fixed point. */
+#define	RUN_MAX_OVRHD		0x0000003dU
+#define	RUN_MAX_OVRHD_RELAX	0x00001800U
+
+/* Put a cap on small object run size.  This overrides RUN_MAX_OVRHD. */
+#define	RUN_MAX_SMALL	(12 * pagesize)
+
+/*
+ * Hyper-threaded CPUs may need a special instruction inside spin loops in
+ * order to yield to another virtual CPU.  If no such instruction is defined
+ * above, make CPU_SPINWAIT a no-op.
+ */
+#ifndef CPU_SPINWAIT
+#  define CPU_SPINWAIT
+#endif
+
+/*
+ * Adaptive spinning must eventually switch to blocking, in order to avoid the
+ * potential for priority inversion deadlock.  Backing off past a certain point
+ * can actually waste time.
+ */
+#define	SPIN_LIMIT_2POW		11
+
+/*
+ * Conversion from spinning to blocking is expensive; we use (1U <<
+ * BLOCK_COST_2POW) to estimate how many more times costly blocking is than
+ * worst-case spinning.
+ */
+#define	BLOCK_COST_2POW		4
+
+#ifdef MALLOC_MAG
+   /*
+    * Default magazine size, in bytes.  max_rounds is calculated to make
+    * optimal use of the space, leaving just enough room for the magazine
+    * header.
+    */
+#  define MAG_SIZE_2POW_DEFAULT	9
+#endif
+
+#ifdef MALLOC_BALANCE
+   /*
+    * We use an exponential moving average to track recent lock contention,
+    * where the size of the history window is N, and alpha=2/(N+1).
+    *
+    * Due to integer math rounding, very small values here can cause
+    * substantial degradation in accuracy, thus making the moving average decay
+    * faster than it would with precise calculation.
+    */
+#  define BALANCE_ALPHA_INV_2POW	9
+
+   /*
+    * Threshold value for the exponential moving contention average at which to
+    * re-assign a thread.
+    */
+#  define BALANCE_THRESHOLD_DEFAULT	(1U << (SPIN_LIMIT_2POW-4))
+#endif
+
+/******************************************************************************/
+
+typedef pthread_mutex_t malloc_mutex_t;
+typedef pthread_mutex_t malloc_spinlock_t;
+
+/* Set to true once the allocator has been initialized. */
+static bool malloc_initialized = false;
+
+/* Used to avoid initialization races. */
+static malloc_mutex_t init_lock = PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP;
+
+/******************************************************************************/
+/*
+ * Statistics data structures.
+ */
+
+#ifdef MALLOC_STATS
+
+typedef struct malloc_bin_stats_s malloc_bin_stats_t;
+struct malloc_bin_stats_s {
+	/*
+	 * Number of allocation requests that corresponded to the size of this
+	 * bin.
+	 */
+	uint64_t	nrequests;
+
+#ifdef MALLOC_MAG
+	/* Number of magazine reloads from this bin. */
+	uint64_t	nmags;
+#endif
+
+	/* Total number of runs created for this bin's size class. */
+	uint64_t	nruns;
+
+	/*
+	 * Total number of runs reused by extracting them from the runs tree for
+	 * this bin's size class.
+	 */
+	uint64_t	reruns;
+
+	/* High-water mark for this bin. */
+	unsigned long	highruns;
+
+	/* Current number of runs in this bin. */
+	unsigned long	curruns;
+};
+
+typedef struct arena_stats_s arena_stats_t;
+struct arena_stats_s {
+	/* Number of bytes currently mapped. */
+	size_t		mapped;
+
+	/*
+	 * Total number of purge sweeps, total number of madvise calls made,
+	 * and total pages purged in order to keep dirty unused memory under
+	 * control.
+	 */
+	uint64_t	npurge;
+	uint64_t	nmadvise;
+	uint64_t	purged;
+
+	/* Per-size-category statistics. */
+	size_t		allocated_small;
+	uint64_t	nmalloc_small;
+	uint64_t	ndalloc_small;
+
+	size_t		allocated_large;
+	uint64_t	nmalloc_large;
+	uint64_t	ndalloc_large;
+
+#ifdef MALLOC_BALANCE
+	/* Number of times this arena reassigned a thread due to contention. */
+	uint64_t	nbalance;
+#endif
+};
+
+typedef struct chunk_stats_s chunk_stats_t;
+struct chunk_stats_s {
+	/* Number of chunks that were allocated. */
+	uint64_t	nchunks;
+
+	/* High-water mark for number of chunks allocated. */
+	unsigned long	highchunks;
+
+	/*
+	 * Current number of chunks allocated.  This value isn't maintained for
+	 * any other purpose, so keep track of it in order to be able to set
+	 * highchunks.
+	 */
+	unsigned long	curchunks;
+};
+
+#endif /* #ifdef MALLOC_STATS */
+
+/******************************************************************************/
+/*
+ * Extent data structures.
+ */
+
+/* Tree of extents. */
+typedef struct extent_node_s extent_node_t;
+struct extent_node_s {
+#ifdef MALLOC_DSS
+	/* Linkage for the size/address-ordered tree. */
+	rb_node(extent_node_t) link_szad;
+#endif
+
+	/* Linkage for the address-ordered tree. */
+	rb_node(extent_node_t) link_ad;
+
+	/* Pointer to the extent that this tree node is responsible for. */
+	void	*addr;
+
+	/* Total region size. */
+	size_t	size;
+};
+typedef rb_tree(extent_node_t) extent_tree_t;
+
+/******************************************************************************/
+/*
+ * Arena data structures.
+ */
+
+typedef struct arena_s arena_t;
+typedef struct arena_bin_s arena_bin_t;
+
+/* Each element of the chunk map corresponds to one page within the chunk. */
+typedef struct arena_chunk_map_s arena_chunk_map_t;
+struct arena_chunk_map_s {
+	/*
+	 * Linkage for run trees.  There are two disjoint uses:
+	 *
+	 * 1) arena_t's runs_avail tree.
+	 * 2) arena_run_t conceptually uses this linkage for in-use non-full
+	 *    runs, rather than directly embedding linkage.
+	 */
+	rb_node(arena_chunk_map_t)	link;
+
+	/*
+	 * Run address (or size) and various flags are stored together.  The bit
+	 * layout looks like (assuming 32-bit system):
+	 *
+	 *   ???????? ???????? ????---- ---kdzla
+	 *
+	 * ? : Unallocated: Run address for first/last pages, unset for internal
+	 *                  pages.
+	 *     Small: Run address.
+	 *     Large: Run size for first page, unset for trailing pages.
+	 * - : Unused.
+	 * k : key?
+	 * d : dirty?
+	 * z : zeroed?
+	 * l : large?
+	 * a : allocated?
+	 *
+	 * Following are example bit patterns for the three types of runs.
+	 *
+	 * r : run address
+	 * s : run size
+	 * x : don't care
+	 * - : 0
+	 * [dzla] : bit set
+	 *
+	 *   Unallocated:
+	 *     ssssssss ssssssss ssss---- --------
+	 *     xxxxxxxx xxxxxxxx xxxx---- ----d---
+	 *     ssssssss ssssssss ssss---- -----z--
+	 *
+	 *   Small:
+	 *     rrrrrrrr rrrrrrrr rrrr---- -------a
+	 *     rrrrrrrr rrrrrrrr rrrr---- -------a
+	 *     rrrrrrrr rrrrrrrr rrrr---- -------a
+	 *
+	 *   Large:
+	 *     ssssssss ssssssss ssss---- ------la
+	 *     -------- -------- -------- ------la
+	 *     -------- -------- -------- ------la
+	 */
+	size_t				bits;
+#define	CHUNK_MAP_KEY		((size_t)0x10U)
+#define	CHUNK_MAP_DIRTY		((size_t)0x08U)
+#define	CHUNK_MAP_ZEROED	((size_t)0x04U)
+#define	CHUNK_MAP_LARGE		((size_t)0x02U)
+#define	CHUNK_MAP_ALLOCATED	((size_t)0x01U)
+};
+typedef rb_tree(arena_chunk_map_t) arena_avail_tree_t;
+typedef rb_tree(arena_chunk_map_t) arena_run_tree_t;
+
+/* Arena chunk header. */
+typedef struct arena_chunk_s arena_chunk_t;
+struct arena_chunk_s {
+	/* Arena that owns the chunk. */
+	arena_t		*arena;
+
+	/* Linkage for the arena's chunks_dirty tree. */
+	rb_node(arena_chunk_t) link_dirty;
+
+	/* Number of dirty pages. */
+	size_t		ndirty;
+
+	/* Map of pages within chunk that keeps track of free/large/small. */
+	arena_chunk_map_t map[1]; /* Dynamically sized. */
+};
+typedef rb_tree(arena_chunk_t) arena_chunk_tree_t;
+
+typedef struct arena_run_s arena_run_t;
+struct arena_run_s {
+#ifdef MALLOC_DEBUG
+	uint32_t	magic;
+#  define ARENA_RUN_MAGIC 0x384adf93
+#endif
+
+	/* Bin this run is associated with. */
+	arena_bin_t	*bin;
+
+	/* Index of first element that might have a free region. */
+	unsigned	regs_minelm;
+
+	/* Number of free regions in run. */
+	unsigned	nfree;
+
+	/* Bitmask of in-use regions (0: in use, 1: free). */
+	unsigned	regs_mask[1]; /* Dynamically sized. */
+};
+
+struct arena_bin_s {
+	/*
+	 * Current run being used to service allocations of this bin's size
+	 * class.
+	 */
+	arena_run_t	*runcur;
+
+	/*
+	 * Tree of non-full runs.  This tree is used when looking for an
+	 * existing run when runcur is no longer usable.  We choose the
+	 * non-full run that is lowest in memory; this policy tends to keep
+	 * objects packed well, and it can also help reduce the number of
+	 * almost-empty chunks.
+	 */
+	arena_run_tree_t runs;
+
+	/* Size of regions in a run for this bin's size class. */
+	size_t		reg_size;
+
+	/* Total size of a run for this bin's size class. */
+	size_t		run_size;
+
+	/* Total number of regions in a run for this bin's size class. */
+	uint32_t	nregs;
+
+	/* Number of elements in a run's regs_mask for this bin's size class. */
+	uint32_t	regs_mask_nelms;
+
+	/* Offset of first region in a run for this bin's size class. */
+	uint32_t	reg0_offset;
+
+#ifdef MALLOC_STATS
+	/* Bin statistics. */
+	malloc_bin_stats_t stats;
+#endif
+};
+
+struct arena_s {
+#ifdef MALLOC_DEBUG
+	uint32_t		magic;
+#  define ARENA_MAGIC 0x947d3d24
+#endif
+
+	/* All operations on this arena require that lock be locked. */
+	pthread_mutex_t		lock;
+
+#ifdef MALLOC_STATS
+	arena_stats_t		stats;
+#endif
+
+	/* Tree of dirty-page-containing chunks this arena manages. */
+	arena_chunk_tree_t	chunks_dirty;
+
+	/*
+	 * In order to avoid rapid chunk allocation/deallocation when an arena
+	 * oscillates right on the cusp of needing a new chunk, cache the most
+	 * recently freed chunk.  The spare is left in the arena's chunk trees
+	 * until it is deleted.
+	 *
+	 * There is one spare chunk per arena, rather than one spare total, in
+	 * order to avoid interactions between multiple threads that could make
+	 * a single spare inadequate.
+	 */
+	arena_chunk_t		*spare;
+
+	/*
+	 * Current count of pages within unused runs that are potentially
+	 * dirty, and for which madvise(... MADV_DONTNEED) has not been called.
+	 * By tracking this, we can institute a limit on how much dirty unused
+	 * memory is mapped for each arena.
+	 */
+	size_t			ndirty;
+
+	/*
+	 * Size/address-ordered tree of this arena's available runs.  This tree
+	 * is used for first-best-fit run allocation.
+	 */
+	arena_avail_tree_t	runs_avail;
+
+#ifdef MALLOC_BALANCE
+	/*
+	 * The arena load balancing machinery needs to keep track of how much
+	 * lock contention there is.  This value is exponentially averaged.
+	 */
+	uint32_t		contention;
+#endif
+
+	/*
+	 * bins is used to store rings of free regions of the following sizes,
+	 * assuming a 16-byte quantum, 4kB pagesize, and default MALLOC_OPTIONS.
+	 *
+	 *   bins[i] | size |
+	 *   --------+------+
+	 *        0  |    2 |
+	 *        1  |    4 |
+	 *        2  |    8 |
+	 *   --------+------+
+	 *        3  |   16 |
+	 *        4  |   32 |
+	 *        5  |   48 |
+	 *        6  |   64 |
+	 *           :      :
+	 *           :      :
+	 *       33  |  496 |
+	 *       34  |  512 |
+	 *   --------+------+
+	 *       35  | 1024 |
+	 *       36  | 2048 |
+	 *   --------+------+
+	 */
+	arena_bin_t		bins[1]; /* Dynamically sized. */
+};
+
+/******************************************************************************/
+/*
+ * Magazine data structures.
+ */
+
+#ifdef MALLOC_MAG
+typedef struct mag_s mag_t;
+struct mag_s {
+	size_t		binind; /* Index of associated bin. */
+	size_t		nrounds;
+	void		*rounds[1]; /* Dynamically sized. */
+};
+
+/*
+ * Magazines are lazily allocated, but once created, they remain until the
+ * associated mag_rack is destroyed.
+ */
+typedef struct bin_mags_s bin_mags_t;
+struct bin_mags_s {
+	mag_t	*curmag;
+	mag_t	*sparemag;
+};
+
+typedef struct mag_rack_s mag_rack_t;
+struct mag_rack_s {
+	bin_mags_t	bin_mags[1]; /* Dynamically sized. */
+};
+#endif
+
+/******************************************************************************/
+/*
+ * Data.
+ */
+
+/* Number of CPUs. */
+static unsigned		ncpus;
+
+/* VM page size. */
+static size_t		pagesize;
+static size_t		pagesize_mask;
+static size_t		pagesize_2pow;
+
+/* Various bin-related settings. */
+#ifdef MALLOC_TINY		/* Number of (2^n)-spaced tiny bins. */
+#  define		ntbins	((unsigned)(QUANTUM_2POW - TINY_MIN_2POW))
+#else
+#  define		ntbins	0
+#endif
+static unsigned		nqbins; /* Number of quantum-spaced bins. */
+static unsigned		ncbins; /* Number of cacheline-spaced bins. */
+static unsigned		nsbins; /* Number of subpage-spaced bins. */
+static unsigned		nbins;
+#ifdef MALLOC_TINY
+#  define		tspace_max	((size_t)(QUANTUM >> 1))
+#endif
+#define			qspace_min	QUANTUM
+static size_t		qspace_max;
+static size_t		cspace_min;
+static size_t		cspace_max;
+static size_t		sspace_min;
+static size_t		sspace_max;
+#define			bin_maxclass	sspace_max
+
+static uint8_t const	*size2bin;
+/*
+ * const_size2bin is a static constant lookup table that in the common case can
+ * be used as-is for size2bin.  For dynamically linked programs, this avoids
+ * a page of memory overhead per process.
+ */
+#define	S2B_1(i)	i,
+#define	S2B_2(i)	S2B_1(i) S2B_1(i)
+#define	S2B_4(i)	S2B_2(i) S2B_2(i)
+#define	S2B_8(i)	S2B_4(i) S2B_4(i)
+#define	S2B_16(i)	S2B_8(i) S2B_8(i)
+#define	S2B_32(i)	S2B_16(i) S2B_16(i)
+#define	S2B_64(i)	S2B_32(i) S2B_32(i)
+#define	S2B_128(i)	S2B_64(i) S2B_64(i)
+#define	S2B_256(i)	S2B_128(i) S2B_128(i)
+static const uint8_t	const_size2bin[(1U << PAGESIZE_2POW) - 255] = {
+	S2B_1(0xffU)		/*    0 */
+#if (QUANTUM_2POW == 4)
+/* 64-bit system ************************/
+#  ifdef MALLOC_TINY
+	S2B_2(0)		/*    2 */
+	S2B_2(1)		/*    4 */
+	S2B_4(2)		/*    8 */
+	S2B_8(3)		/*   16 */
+#    define S2B_QMIN 3
+#  else
+	S2B_16(0)		/*   16 */
+#    define S2B_QMIN 0
+#  endif
+	S2B_16(S2B_QMIN + 1)	/*   32 */
+	S2B_16(S2B_QMIN + 2)	/*   48 */
+	S2B_16(S2B_QMIN + 3)	/*   64 */
+	S2B_16(S2B_QMIN + 4)	/*   80 */
+	S2B_16(S2B_QMIN + 5)	/*   96 */
+	S2B_16(S2B_QMIN + 6)	/*  112 */
+	S2B_16(S2B_QMIN + 7)	/*  128 */
+#  define S2B_CMIN (S2B_QMIN + 8)
+#else
+/* 32-bit system ************************/
+#  ifdef MALLOC_TINY
+	S2B_2(0)		/*    2 */
+	S2B_2(1)		/*    4 */
+	S2B_4(2)		/*    8 */
+#    define S2B_QMIN 2
+#  else
+	S2B_8(0)		/*    8 */
+#    define S2B_QMIN 0
+#  endif
+	S2B_8(S2B_QMIN + 1)	/*   16 */
+	S2B_8(S2B_QMIN + 2)	/*   24 */
+	S2B_8(S2B_QMIN + 3)	/*   32 */
+	S2B_8(S2B_QMIN + 4)	/*   40 */
+	S2B_8(S2B_QMIN + 5)	/*   48 */
+	S2B_8(S2B_QMIN + 6)	/*   56 */
+	S2B_8(S2B_QMIN + 7)	/*   64 */
+	S2B_8(S2B_QMIN + 8)	/*   72 */
+	S2B_8(S2B_QMIN + 9)	/*   80 */
+	S2B_8(S2B_QMIN + 10)	/*   88 */
+	S2B_8(S2B_QMIN + 11)	/*   96 */
+	S2B_8(S2B_QMIN + 12)	/*  104 */
+	S2B_8(S2B_QMIN + 13)	/*  112 */
+	S2B_8(S2B_QMIN + 14)	/*  120 */
+	S2B_8(S2B_QMIN + 15)	/*  128 */
+#  define S2B_CMIN (S2B_QMIN + 16)
+#endif
+/****************************************/
+	S2B_64(S2B_CMIN + 0)	/*  192 */
+	S2B_64(S2B_CMIN + 1)	/*  256 */
+	S2B_64(S2B_CMIN + 2)	/*  320 */
+	S2B_64(S2B_CMIN + 3)	/*  384 */
+	S2B_64(S2B_CMIN + 4)	/*  448 */
+	S2B_64(S2B_CMIN + 5)	/*  512 */
+#  define S2B_SMIN (S2B_CMIN + 6)
+	S2B_256(S2B_SMIN + 0)	/*  768 */
+	S2B_256(S2B_SMIN + 1)	/* 1024 */
+	S2B_256(S2B_SMIN + 2)	/* 1280 */
+	S2B_256(S2B_SMIN + 3)	/* 1536 */
+	S2B_256(S2B_SMIN + 4)	/* 1792 */
+	S2B_256(S2B_SMIN + 5)	/* 2048 */
+	S2B_256(S2B_SMIN + 6)	/* 2304 */
+	S2B_256(S2B_SMIN + 7)	/* 2560 */
+	S2B_256(S2B_SMIN + 8)	/* 2816 */
+	S2B_256(S2B_SMIN + 9)	/* 3072 */
+	S2B_256(S2B_SMIN + 10)	/* 3328 */
+	S2B_256(S2B_SMIN + 11)	/* 3584 */
+	S2B_256(S2B_SMIN + 12)	/* 3840 */
+#if (PAGESIZE_2POW == 13)
+	S2B_256(S2B_SMIN + 13)	/* 4096 */
+	S2B_256(S2B_SMIN + 14)	/* 4352 */
+	S2B_256(S2B_SMIN + 15)	/* 4608 */
+	S2B_256(S2B_SMIN + 16)	/* 4864 */
+	S2B_256(S2B_SMIN + 17)	/* 5120 */
+	S2B_256(S2B_SMIN + 18)	/* 5376 */
+	S2B_256(S2B_SMIN + 19)	/* 5632 */
+	S2B_256(S2B_SMIN + 20)	/* 5888 */
+	S2B_256(S2B_SMIN + 21)	/* 6144 */
+	S2B_256(S2B_SMIN + 22)	/* 6400 */
+	S2B_256(S2B_SMIN + 23)	/* 6656 */
+	S2B_256(S2B_SMIN + 24)	/* 6912 */
+	S2B_256(S2B_SMIN + 25)	/* 7168 */
+	S2B_256(S2B_SMIN + 26)	/* 7424 */
+	S2B_256(S2B_SMIN + 27)	/* 7680 */
+	S2B_256(S2B_SMIN + 28)	/* 7936 */
+#endif
+};
+#undef S2B_1
+#undef S2B_2
+#undef S2B_4
+#undef S2B_8
+#undef S2B_16
+#undef S2B_32
+#undef S2B_64
+#undef S2B_128
+#undef S2B_256
+#undef S2B_QMIN
+#undef S2B_CMIN
+#undef S2B_SMIN
+
+#ifdef MALLOC_MAG
+static size_t		max_rounds;
+#endif
+
+/* Various chunk-related settings. */
+static size_t		chunksize;
+static size_t		chunksize_mask; /* (chunksize - 1). */
+static size_t		chunk_npages;
+static size_t		arena_chunk_header_npages;
+static size_t		arena_maxclass; /* Max size class for arenas. */
+
+/********/
+/*
+ * Chunks.
+ */
+
+/* Protects chunk-related data structures. */
+static malloc_mutex_t	huge_mtx;
+
+/* Tree of chunks that are stand-alone huge allocations. */
+static extent_tree_t	huge;
+
+#ifdef MALLOC_DSS
+/*
+ * Protects sbrk() calls.  This avoids malloc races among threads, though it
+ * does not protect against races with threads that call sbrk() directly.
+ */
+static malloc_mutex_t	dss_mtx;
+/* Base address of the DSS. */
+static void		*dss_base;
+/* Current end of the DSS, or ((void *)-1) if the DSS is exhausted. */
+static void		*dss_prev;
+/* Current upper limit on DSS addresses. */
+static void		*dss_max;
+
+/*
+ * Trees of chunks that were previously allocated (trees differ only in node
+ * ordering).  These are used when allocating chunks, in an attempt to re-use
+ * address space.  Depending on function, different tree orderings are needed,
+ * which is why there are two trees with the same contents.
+ */
+static extent_tree_t	dss_chunks_szad;
+static extent_tree_t	dss_chunks_ad;
+#endif
+
+#ifdef MALLOC_STATS
+/* Huge allocation statistics. */
+static uint64_t		huge_nmalloc;
+static uint64_t		huge_ndalloc;
+static size_t		huge_allocated;
+#endif
+
+/****************************/
+/*
+ * base (internal allocation).
+ */
+
+/*
+ * Current pages that are being used for internal memory allocations.  These
+ * pages are carved up in cacheline-size quanta, so that there is no chance of
+ * false cache line sharing.
+ */
+static void		*base_pages;
+static void		*base_next_addr;
+static void		*base_past_addr; /* Addr immediately past base_pages. */
+static extent_node_t	*base_nodes;
+static malloc_mutex_t	base_mtx;
+#ifdef MALLOC_STATS
+static size_t		base_mapped;
+#endif
+
+/********/
+/*
+ * Arenas.
+ */
+
+/*
+ * Arenas that are used to service external requests.  Not all elements of the
+ * arenas array are necessarily used; arenas are created lazily as needed.
+ */
+static arena_t		**arenas;
+static unsigned		narenas;
+#ifndef NO_TLS
+#  ifdef MALLOC_BALANCE
+static unsigned		narenas_2pow;
+#  else
+static unsigned		next_arena;
+#  endif
+#endif
+static pthread_mutex_t	arenas_lock; /* Protects arenas initialization. */
+
+#ifndef NO_TLS
+/*
+ * Map of pthread_self() --> arenas[???], used for selecting an arena to use
+ * for allocations.
+ */
+static __thread arena_t	*arenas_map;
+#endif
+
+#ifdef MALLOC_MAG
+/*
+ * Map of thread-specific magazine racks, used for thread-specific object
+ * caching.
+ */
+static __thread mag_rack_t	*mag_rack;
+#endif
+
+#ifdef MALLOC_STATS
+/* Chunk statistics. */
+static chunk_stats_t	stats_chunks;
+#endif
+
+/*******************************/
+/*
+ * Runtime configuration options.
+ */
+const char	*_malloc_options;
+
+#ifndef MALLOC_PRODUCTION
+static bool	opt_abort = true;
+static bool	opt_junk = true;
+#else
+static bool	opt_abort = false;
+static bool	opt_junk = false;
+#endif
+#ifdef MALLOC_DSS
+static bool	opt_dss = true;
+static bool	opt_mmap = true;
+#endif
+#ifdef MALLOC_MAG
+static bool	opt_mag = true;
+static size_t	opt_mag_size_2pow = MAG_SIZE_2POW_DEFAULT;
+#endif
+static size_t	opt_dirty_max = DIRTY_MAX_DEFAULT;
+#ifdef MALLOC_BALANCE
+static uint64_t	opt_balance_threshold = BALANCE_THRESHOLD_DEFAULT;
+#endif
+static bool	opt_print_stats = false;
+static size_t	opt_qspace_max_2pow = QSPACE_MAX_2POW_DEFAULT;
+static size_t	opt_cspace_max_2pow = CSPACE_MAX_2POW_DEFAULT;
+static size_t	opt_chunk_2pow = CHUNK_2POW_DEFAULT;
+static bool	opt_utrace = false;
+static bool	opt_sysv = false;
+static bool	opt_xmalloc = false;
+static bool	opt_zero = false;
+static int	opt_narenas_lshift = 0;
+
+typedef struct {
+	void	*p;
+	size_t	s;
+	void	*r;
+} malloc_utrace_t;
+
+#ifdef MALLOC_STATS
+#define	UTRACE(a, b, c)							\
+	if (opt_utrace) {						\
+		malloc_utrace_t ut;					\
+		ut.p = (a);						\
+		ut.s = (b);						\
+		ut.r = (c);						\
+		utrace(&ut, sizeof(ut));				\
+	}
+#else
+#define	UTRACE(a, b, c)
+#endif
+
+/******************************************************************************/
+/*
+ * Begin function prototypes for non-inline static functions.
+ */
+
+static bool	malloc_mutex_init(malloc_mutex_t *mutex);
+static bool	malloc_spin_init(pthread_mutex_t *lock);
+static void	wrtmessage(const char *p1, const char *p2, const char *p3,
+		const char *p4);
+#ifdef MALLOC_STATS
+static void	malloc_printf(const char *format, ...);
+#endif
+static char	*umax2s(uintmax_t x, char *s);
+#ifdef MALLOC_DSS
+static bool	base_pages_alloc_dss(size_t minsize);
+#endif
+static bool	base_pages_alloc_mmap(size_t minsize);
+static bool	base_pages_alloc(size_t minsize);
+static void	*base_alloc(size_t size);
+static void	*base_calloc(size_t number, size_t size);
+static extent_node_t *base_node_alloc(void);
+static void	base_node_dealloc(extent_node_t *node);
+#ifdef MALLOC_STATS
+static void	stats_print(arena_t *arena);
+#endif
+static void	*pages_map(void *addr, size_t size);
+static void	pages_unmap(void *addr, size_t size);
+#ifdef MALLOC_DSS
+static void	*chunk_alloc_dss(size_t size);
+static void	*chunk_recycle_dss(size_t size, bool zero);
+#endif
+static void	*chunk_alloc_mmap(size_t size);
+static void	*chunk_alloc(size_t size, bool zero);
+#ifdef MALLOC_DSS
+static extent_node_t *chunk_dealloc_dss_record(void *chunk, size_t size);
+static bool	chunk_dealloc_dss(void *chunk, size_t size);
+#endif
+static void	chunk_dealloc_mmap(void *chunk, size_t size);
+static void	chunk_dealloc(void *chunk, size_t size);
+#ifndef NO_TLS
+static arena_t	*choose_arena_hard(void);
+#endif
+static void	arena_run_split(arena_t *arena, arena_run_t *run, size_t size,
+    bool large, bool zero);
+static arena_chunk_t *arena_chunk_alloc(arena_t *arena);
+static void	arena_chunk_dealloc(arena_t *arena, arena_chunk_t *chunk);
+static arena_run_t *arena_run_alloc(arena_t *arena, size_t size, bool large,
+    bool zero);
+static void	arena_purge(arena_t *arena);
+static void	arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty);
+static void	arena_run_trim_head(arena_t *arena, arena_chunk_t *chunk,
+    arena_run_t *run, size_t oldsize, size_t newsize);
+static void	arena_run_trim_tail(arena_t *arena, arena_chunk_t *chunk,
+    arena_run_t *run, size_t oldsize, size_t newsize, bool dirty);
+static arena_run_t *arena_bin_nonfull_run_get(arena_t *arena, arena_bin_t *bin);
+static void	*arena_bin_malloc_hard(arena_t *arena, arena_bin_t *bin);
+static size_t	arena_bin_run_size_calc(arena_bin_t *bin, size_t min_run_size);
+#ifdef MALLOC_BALANCE
+static void	arena_lock_balance_hard(arena_t *arena);
+#endif
+#ifdef MALLOC_MAG
+static void	mag_load(mag_t *mag);
+#endif
+static void	*arena_malloc_large(arena_t *arena, size_t size, bool zero);
+static void	*arena_palloc(arena_t *arena, size_t alignment, size_t size,
+    size_t alloc_size);
+static size_t	arena_salloc(const void *ptr);
+#ifdef MALLOC_MAG
+static void	mag_unload(mag_t *mag);
+#endif
+static void	arena_dalloc_large(arena_t *arena, arena_chunk_t *chunk,
+    void *ptr);
+static void	arena_ralloc_large_shrink(arena_t *arena, arena_chunk_t *chunk,
+    void *ptr, size_t size, size_t oldsize);
+static bool	arena_ralloc_large_grow(arena_t *arena, arena_chunk_t *chunk,
+    void *ptr, size_t size, size_t oldsize);
+static bool	arena_ralloc_large(void *ptr, size_t size, size_t oldsize);
+static void	*arena_ralloc(void *ptr, size_t size, size_t oldsize);
+static bool	arena_new(arena_t *arena);
+static arena_t	*arenas_extend(unsigned ind);
+#ifdef MALLOC_MAG
+static mag_t	*mag_create(arena_t *arena, size_t binind);
+static void	mag_destroy(mag_t *mag);
+static mag_rack_t *mag_rack_create(arena_t *arena);
+static void	mag_rack_destroy(mag_rack_t *rack);
+#endif
+static void	*huge_malloc(size_t size, bool zero);
+static void	*huge_palloc(size_t alignment, size_t size);
+static void	*huge_ralloc(void *ptr, size_t size, size_t oldsize);
+static void	huge_dalloc(void *ptr);
+static void	malloc_print_stats(void);
+#ifdef MALLOC_DEBUG
+static void	size2bin_validate(void);
+#endif
+static bool	size2bin_init(void);
+static bool	size2bin_init_hard(void);
+static unsigned	malloc_ncpus(void);
+static bool	malloc_init_hard(void);
+void		_malloc_prefork(void);
+void		_malloc_postfork(void);
+
+/*
+ * End function prototypes.
+ */
+/******************************************************************************/
+
+static void
+wrtmessage(const char *p1, const char *p2, const char *p3, const char *p4)
+{
+
+	write(STDERR_FILENO, p1, strlen(p1));
+	write(STDERR_FILENO, p2, strlen(p2));
+	write(STDERR_FILENO, p3, strlen(p3));
+	write(STDERR_FILENO, p4, strlen(p4));
+}
+
+#define	_malloc_message malloc_message
+void	(*_malloc_message)(const char *p1, const char *p2, const char *p3,
+	    const char *p4) = wrtmessage;
+
+/*
+ * We don't want to depend on vsnprintf() for production builds, since that can
+ * cause unnecessary bloat for static binaries.  umax2s() provides minimal
+ * integer printing functionality, so that malloc_printf() use can be limited to
+ * MALLOC_STATS code.
+ */
+#define	UMAX2S_BUFSIZE	21
+static char *
+umax2s(uintmax_t x, char *s)
+{
+	unsigned i;
+
+	i = UMAX2S_BUFSIZE - 1;
+	s[i] = '\0';
+	do {
+		i--;
+		s[i] = "0123456789"[x % 10];
+		x /= 10;
+	} while (x > 0);
+
+	return (&s[i]);
+}
+
+/*
+ * Define a custom assert() in order to reduce the chances of deadlock during
+ * assertion failure.
+ */
+#ifdef MALLOC_DEBUG
+#  define assert(e) do {						\
+	if (!(e)) {							\
+		char line_buf[UMAX2S_BUFSIZE];				\
+		_malloc_message(__FILE__, ":", umax2s(__LINE__,		\
+		    line_buf), ": Failed assertion: ");			\
+		_malloc_message("\"", #e, "\"\n", "");			\
+		abort();						\
+	}								\
+} while (0)
+#else
+#define assert(e)
+#endif
+
+#ifdef MALLOC_STATS
+static int
+utrace(const void *addr, size_t len)
+{
+	malloc_utrace_t *ut = (malloc_utrace_t *)addr;
+
+	assert(len == sizeof(malloc_utrace_t));
+
+	if (ut->p == NULL && ut->s == 0 && ut->r == NULL)
+		malloc_printf("%d x USER malloc_init()\n", getpid());
+	else if (ut->p == NULL && ut->r != NULL) {
+		malloc_printf("%d x USER %p = malloc(%zu)\n", getpid(), ut->r,
+		    ut->s);
+	} else if (ut->p != NULL && ut->r != NULL) {
+		malloc_printf("%d x USER %p = realloc(%p, %zu)\n", getpid(),
+		    ut->r, ut->p, ut->s);
+	} else
+		malloc_printf("%d x USER free(%p)\n", getpid(), ut->p);
+
+	return (0);
+}
+#endif
+
+static inline const char *
+_getprogname(void)
+{
+
+	return ("<jemalloc>");
+}
+
+#ifdef MALLOC_STATS
+/*
+ * Print to stderr in such a way as to (hopefully) avoid memory allocation.
+ */
+static void
+malloc_printf(const char *format, ...)
+{
+	char buf[4096];
+	va_list ap;
+
+	va_start(ap, format);
+	vsnprintf(buf, sizeof(buf), format, ap);
+	va_end(ap);
+	_malloc_message(buf, "", "", "");
+}
+#endif
+
+/******************************************************************************/
+/*
+ * Begin mutex.
+ */
+
+static bool
+malloc_mutex_init(malloc_mutex_t *mutex)
+{
+	pthread_mutexattr_t attr;
+
+	if (pthread_mutexattr_init(&attr) != 0)
+		return (true);
+	pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ADAPTIVE_NP);
+	if (pthread_mutex_init(mutex, &attr) != 0) {
+		pthread_mutexattr_destroy(&attr);
+		return (true);
+	}
+	pthread_mutexattr_destroy(&attr);
+
+	return (false);
+}
+
+static inline void
+malloc_mutex_lock(malloc_mutex_t *mutex)
+{
+
+	if (__isthreaded)
+		pthread_mutex_lock(mutex);
+}
+
+static inline void
+malloc_mutex_unlock(malloc_mutex_t *mutex)
+{
+
+	if (__isthreaded)
+		pthread_mutex_unlock(mutex);
+}
+
+/*
+ * End mutex.
+ */
+/******************************************************************************/
+/*
+ * Begin spin lock.  Spin locks here are actually adaptive mutexes that block
+ * after a period of spinning, because unbounded spinning would allow for
+ * priority inversion.
+ */
+
+static bool
+malloc_spin_init(pthread_mutex_t *lock)
+{
+
+	if (pthread_mutex_init(lock, NULL) != 0)
+		return (true);
+
+	return (false);
+}
+
+static inline unsigned
+malloc_spin_lock(pthread_mutex_t *lock)
+{
+	unsigned ret = 0;
+
+	if (__isthreaded) {
+		if (pthread_mutex_trylock(lock) != 0) {
+			unsigned i;
+			volatile unsigned j;
+
+			/* Exponentially back off. */
+			for (i = 1; i <= SPIN_LIMIT_2POW; i++) {
+				for (j = 0; j < (1U << i); j++) {
+					ret++;
+					CPU_SPINWAIT;
+				}
+
+				if (pthread_mutex_trylock(lock) == 0)
+					return (ret);
+			}
+
+			/*
+			 * Spinning failed.  Block until the lock becomes
+			 * available, in order to avoid indefinite priority
+			 * inversion.
+			 */
+			pthread_mutex_lock(lock);
+			assert((ret << BLOCK_COST_2POW) != 0);
+			return (ret << BLOCK_COST_2POW);
+		}
+	}
+
+	return (ret);
+}
+
+static inline void
+malloc_spin_unlock(pthread_mutex_t *lock)
+{
+
+	if (__isthreaded)
+		pthread_mutex_unlock(lock);
+}
+
+/*
+ * End spin lock.
+ */
+/******************************************************************************/
+/*
+ * Begin Utility functions/macros.
+ */
+
+/* Return the chunk address for allocation address a. */
+#define	CHUNK_ADDR2BASE(a)						\
+	((void *)((uintptr_t)(a) & ~chunksize_mask))
+
+/* Return the chunk offset of address a. */
+#define	CHUNK_ADDR2OFFSET(a)						\
+	((size_t)((uintptr_t)(a) & chunksize_mask))
+
+/* Return the smallest chunk multiple that is >= s. */
+#define	CHUNK_CEILING(s)						\
+	(((s) + chunksize_mask) & ~chunksize_mask)
+
+/* Return the smallest quantum multiple that is >= a. */
+#define	QUANTUM_CEILING(a)						\
+	(((a) + QUANTUM_MASK) & ~QUANTUM_MASK)
+
+/* Return the smallest cacheline multiple that is >= s. */
+#define	CACHELINE_CEILING(s)						\
+	(((s) + CACHELINE_MASK) & ~CACHELINE_MASK)
+
+/* Return the smallest subpage multiple that is >= s. */
+#define	SUBPAGE_CEILING(s)						\
+	(((s) + SUBPAGE_MASK) & ~SUBPAGE_MASK)
+
+/* Return the smallest pagesize multiple that is >= s. */
+#define	PAGE_CEILING(s)							\
+	(((s) + pagesize_mask) & ~pagesize_mask)
+
+#ifdef MALLOC_TINY
+/* Compute the smallest power of 2 that is >= x. */
+static inline size_t
+pow2_ceil(size_t x)
+{
+
+	x--;
+	x |= x >> 1;
+	x |= x >> 2;
+	x |= x >> 4;
+	x |= x >> 8;
+	x |= x >> 16;
+#if (SIZEOF_PTR == 8)
+	x |= x >> 32;
+#endif
+	x++;
+	return (x);
+}
+#endif
+
+#ifdef MALLOC_BALANCE
+/*
+ * Use a simple linear congruential pseudo-random number generator:
+ *
+ *   prn(y) = (a*x + c) % m
+ *
+ * where the following constants ensure maximal period:
+ *
+ *   a == Odd number (relatively prime to 2^n), and (a-1) is a multiple of 4.
+ *   c == Odd number (relatively prime to 2^n).
+ *   m == 2^32
+ *
+ * See Knuth's TAOCP 3rd Ed., Vol. 2, pg. 17 for details on these constraints.
+ *
+ * This choice of m has the disadvantage that the quality of the bits is
+ * proportional to bit position.  For example. the lowest bit has a cycle of 2,
+ * the next has a cycle of 4, etc.  For this reason, we prefer to use the upper
+ * bits.
+ */
+#  define PRN_DEFINE(suffix, var, a, c)					\
+static inline void							\
+sprn_##suffix(uint32_t seed)						\
+{									\
+	var = seed;							\
+}									\
+									\
+static inline uint32_t							\
+prn_##suffix(uint32_t lg_range)						\
+{									\
+	uint32_t ret, x;						\
+									\
+	assert(lg_range > 0);						\
+	assert(lg_range <= 32);						\
+									\
+	x = (var * (a)) + (c);						\
+	var = x;							\
+	ret = x >> (32 - lg_range);					\
+									\
+	return (ret);							\
+}
+#  define SPRN(suffix, seed)	sprn_##suffix(seed)
+#  define PRN(suffix, lg_range)	prn_##suffix(lg_range)
+#endif
+
+#ifdef MALLOC_BALANCE
+/* Define the PRNG used for arena assignment. */
+static __thread uint32_t balance_x;
+PRN_DEFINE(balance, balance_x, 1297, 1301)
+#endif
+
+/******************************************************************************/
+
+#ifdef MALLOC_DSS
+static bool
+base_pages_alloc_dss(size_t minsize)
+{
+
+	/*
+	 * Do special DSS allocation here, since base allocations don't need to
+	 * be chunk-aligned.
+	 */
+	malloc_mutex_lock(&dss_mtx);
+	if (dss_prev != (void *)-1) {
+		intptr_t incr;
+		size_t csize = CHUNK_CEILING(minsize);
+
+		do {
+			/* Get the current end of the DSS. */
+			dss_max = sbrk(0);
+
+			/*
+			 * Calculate how much padding is necessary to
+			 * chunk-align the end of the DSS.  Don't worry about
+			 * dss_max not being chunk-aligned though.
+			 */
+			incr = (intptr_t)chunksize
+			    - (intptr_t)CHUNK_ADDR2OFFSET(dss_max);
+			assert(incr >= 0);
+			if ((size_t)incr < minsize)
+				incr += csize;
+
+			dss_prev = sbrk(incr);
+			if (dss_prev == dss_max) {
+				/* Success. */
+				dss_max = (void *)((intptr_t)dss_prev + incr);
+				base_pages = dss_prev;
+				base_next_addr = base_pages;
+				base_past_addr = dss_max;
+#ifdef MALLOC_STATS
+				base_mapped += incr;
+#endif
+				malloc_mutex_unlock(&dss_mtx);
+				return (false);
+			}
+		} while (dss_prev != (void *)-1);
+	}
+	malloc_mutex_unlock(&dss_mtx);
+
+	return (true);
+}
+#endif
+
+static bool
+base_pages_alloc_mmap(size_t minsize)
+{
+	size_t csize;
+
+	assert(minsize != 0);
+	csize = PAGE_CEILING(minsize);
+	base_pages = pages_map(NULL, csize);
+	if (base_pages == NULL)
+		return (true);
+	base_next_addr = base_pages;
+	base_past_addr = (void *)((uintptr_t)base_pages + csize);
+#ifdef MALLOC_STATS
+	base_mapped += csize;
+#endif
+
+	return (false);
+}
+
+static bool
+base_pages_alloc(size_t minsize)
+{
+
+#ifdef MALLOC_DSS
+	if (opt_dss) {
+		if (base_pages_alloc_dss(minsize) == false)
+			return (false);
+	}
+
+	if (opt_mmap && minsize != 0)
+#endif
+	{
+		if (base_pages_alloc_mmap(minsize) == false)
+			return (false);
+	}
+
+	return (true);
+}
+
+static void *
+base_alloc(size_t size)
+{
+	void *ret;
+	size_t csize;
+
+	/* Round size up to nearest multiple of the cacheline size. */
+	csize = CACHELINE_CEILING(size);
+
+	malloc_mutex_lock(&base_mtx);
+	/* Make sure there's enough space for the allocation. */
+	if ((uintptr_t)base_next_addr + csize > (uintptr_t)base_past_addr) {
+		if (base_pages_alloc(csize)) {
+			malloc_mutex_unlock(&base_mtx);
+			return (NULL);
+		}
+	}
+	/* Allocate. */
+	ret = base_next_addr;
+	base_next_addr = (void *)((uintptr_t)base_next_addr + csize);
+	malloc_mutex_unlock(&base_mtx);
+
+	return (ret);
+}
+
+static void *
+base_calloc(size_t number, size_t size)
+{
+	void *ret;
+
+	ret = base_alloc(number * size);
+	memset(ret, 0, number * size);
+
+	return (ret);
+}
+
+static extent_node_t *
+base_node_alloc(void)
+{
+	extent_node_t *ret;
+
+	malloc_mutex_lock(&base_mtx);
+	if (base_nodes != NULL) {
+		ret = base_nodes;
+		base_nodes = *(extent_node_t **)ret;
+		malloc_mutex_unlock(&base_mtx);
+	} else {
+		malloc_mutex_unlock(&base_mtx);
+		ret = (extent_node_t *)base_alloc(sizeof(extent_node_t));
+	}
+
+	return (ret);
+}
+
+static void
+base_node_dealloc(extent_node_t *node)
+{
+
+	malloc_mutex_lock(&base_mtx);
+	*(extent_node_t **)node = base_nodes;
+	base_nodes = node;
+	malloc_mutex_unlock(&base_mtx);
+}
+
+/******************************************************************************/
+
+#ifdef MALLOC_STATS
+static void
+stats_print(arena_t *arena)
+{
+	unsigned i, gap_start;
+
+	malloc_printf("dirty: %zu page%s dirty, %llu sweep%s,"
+	    " %llu madvise%s, %llu page%s purged\n",
+	    arena->ndirty, arena->ndirty == 1 ? "" : "s",
+	    arena->stats.npurge, arena->stats.npurge == 1 ? "" : "s",
+	    arena->stats.nmadvise, arena->stats.nmadvise == 1 ? "" : "s",
+	    arena->stats.purged, arena->stats.purged == 1 ? "" : "s");
+
+	malloc_printf("            allocated      nmalloc      ndalloc\n");
+	malloc_printf("small:   %12zu %12llu %12llu\n",
+	    arena->stats.allocated_small, arena->stats.nmalloc_small,
+	    arena->stats.ndalloc_small);
+	malloc_printf("large:   %12zu %12llu %12llu\n",
+	    arena->stats.allocated_large, arena->stats.nmalloc_large,
+	    arena->stats.ndalloc_large);
+	malloc_printf("total:   %12zu %12llu %12llu\n",
+	    arena->stats.allocated_small + arena->stats.allocated_large,
+	    arena->stats.nmalloc_small + arena->stats.nmalloc_large,
+	    arena->stats.ndalloc_small + arena->stats.ndalloc_large);
+	malloc_printf("mapped:  %12zu\n", arena->stats.mapped);
+
+#ifdef MALLOC_MAG
+	if (__isthreaded && opt_mag) {
+		malloc_printf("bins:     bin   size regs pgs      mags   "
+		    "newruns    reruns maxruns curruns\n");
+	} else {
+#endif
+		malloc_printf("bins:     bin   size regs pgs  requests   "
+		    "newruns    reruns maxruns curruns\n");
+#ifdef MALLOC_MAG
+	}
+#endif
+	for (i = 0, gap_start = UINT_MAX; i < nbins; i++) {
+		if (arena->bins[i].stats.nruns == 0) {
+			if (gap_start == UINT_MAX)
+				gap_start = i;
+		} else {
+			if (gap_start != UINT_MAX) {
+				if (i > gap_start + 1) {
+					/* Gap of more than one size class. */
+					malloc_printf("[%u..%u]\n",
+					    gap_start, i - 1);
+				} else {
+					/* Gap of one size class. */
+					malloc_printf("[%u]\n", gap_start);
+				}
+				gap_start = UINT_MAX;
+			}
+			malloc_printf(
+			    "%13u %1s %4u %4u %3u %9llu %9llu"
+			    " %9llu %7lu %7lu\n",
+			    i,
+			    i < ntbins ? "T" : i < ntbins + nqbins ? "Q" :
+			    i < ntbins + nqbins + ncbins ? "C" : "S",
+			    arena->bins[i].reg_size,
+			    arena->bins[i].nregs,
+			    arena->bins[i].run_size >> pagesize_2pow,
+#ifdef MALLOC_MAG
+			    (__isthreaded && opt_mag) ?
+			    arena->bins[i].stats.nmags :
+#endif
+			    arena->bins[i].stats.nrequests,
+			    arena->bins[i].stats.nruns,
+			    arena->bins[i].stats.reruns,
+			    arena->bins[i].stats.highruns,
+			    arena->bins[i].stats.curruns);
+		}
+	}
+	if (gap_start != UINT_MAX) {
+		if (i > gap_start + 1) {
+			/* Gap of more than one size class. */
+			malloc_printf("[%u..%u]\n", gap_start, i - 1);
+		} else {
+			/* Gap of one size class. */
+			malloc_printf("[%u]\n", gap_start);
+		}
+	}
+}
+#endif
+
+/*
+ * End Utility functions/macros.
+ */
+/******************************************************************************/
+/*
+ * Begin extent tree code.
+ */
+
+#ifdef MALLOC_DSS
+static inline int
+extent_szad_comp(extent_node_t *a, extent_node_t *b)
+{
+	int ret;
+	size_t a_size = a->size;
+	size_t b_size = b->size;
+
+	ret = (a_size > b_size) - (a_size < b_size);
+	if (ret == 0) {
+		uintptr_t a_addr = (uintptr_t)a->addr;
+		uintptr_t b_addr = (uintptr_t)b->addr;
+
+		ret = (a_addr > b_addr) - (a_addr < b_addr);
+	}
+
+	return (ret);
+}
+
+/* Wrap red-black tree macros in functions. */
+rb_wrap(static, extent_tree_szad_, extent_tree_t, extent_node_t,
+    link_szad, extent_szad_comp)
+#endif
+
+static inline int
+extent_ad_comp(extent_node_t *a, extent_node_t *b)
+{
+	uintptr_t a_addr = (uintptr_t)a->addr;
+	uintptr_t b_addr = (uintptr_t)b->addr;
+
+	return ((a_addr > b_addr) - (a_addr < b_addr));
+}
+
+/* Wrap red-black tree macros in functions. */
+rb_wrap(static, extent_tree_ad_, extent_tree_t, extent_node_t, link_ad,
+    extent_ad_comp)
+
+/*
+ * End extent tree code.
+ */
+/******************************************************************************/
+/*
+ * Begin chunk management functions.
+ */
+
+static void *
+pages_map(void *addr, size_t size)
+{
+	void *ret;
+
+	/*
+	 * We don't use MAP_FIXED here, because it can cause the *replacement*
+	 * of existing mappings, and we only want to create new mappings.
+	 */
+	ret = mmap(addr, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON,
+	    -1, 0);
+	assert(ret != NULL);
+
+	if (ret == MAP_FAILED)
+		ret = NULL;
+	else if (addr != NULL && ret != addr) {
+		/*
+		 * We succeeded in mapping memory, but not in the right place.
+		 */
+		if (munmap(ret, size) == -1) {
+			char buf[STRERROR_BUF];
+
+			strerror_r(errno, buf, sizeof(buf));
+			_malloc_message(_getprogname(),
+			    ": (malloc) Error in munmap(): ", buf, "\n");
+			if (opt_abort)
+				abort();
+		}
+		ret = NULL;
+	}
+
+	assert(ret == NULL || (addr == NULL && ret != addr)
+	    || (addr != NULL && ret == addr));
+	return (ret);
+}
+
+static void
+pages_unmap(void *addr, size_t size)
+{
+
+	if (munmap(addr, size) == -1) {
+		char buf[STRERROR_BUF];
+
+		strerror_r(errno, buf, sizeof(buf));
+		_malloc_message(_getprogname(),
+		    ": (malloc) Error in munmap(): ", buf, "\n");
+		if (opt_abort)
+			abort();
+	}
+}
+
+#ifdef MALLOC_DSS
+static void *
+chunk_alloc_dss(size_t size)
+{
+
+	/*
+	 * sbrk() uses a signed increment argument, so take care not to
+	 * interpret a huge allocation request as a negative increment.
+	 */
+	if ((intptr_t)size < 0)
+		return (NULL);
+
+	malloc_mutex_lock(&dss_mtx);
+	if (dss_prev != (void *)-1) {
+		intptr_t incr;
+
+		/*
+		 * The loop is necessary to recover from races with other
+		 * threads that are using the DSS for something other than
+		 * malloc.
+		 */
+		do {
+			void *ret;
+
+			/* Get the current end of the DSS. */
+			dss_max = sbrk(0);
+
+			/*
+			 * Calculate how much padding is necessary to
+			 * chunk-align the end of the DSS.
+			 */
+			incr = (intptr_t)size
+			    - (intptr_t)CHUNK_ADDR2OFFSET(dss_max);
+			if (incr == (intptr_t)size)
+				ret = dss_max;
+			else {
+				ret = (void *)((intptr_t)dss_max + incr);
+				incr += size;
+			}
+
+			dss_prev = sbrk(incr);
+			if (dss_prev == dss_max) {
+				/* Success. */
+				dss_max = (void *)((intptr_t)dss_prev + incr);
+				malloc_mutex_unlock(&dss_mtx);
+				return (ret);
+			}
+		} while (dss_prev != (void *)-1);
+	}
+	malloc_mutex_unlock(&dss_mtx);
+
+	return (NULL);
+}
+
+static void *
+chunk_recycle_dss(size_t size, bool zero)
+{
+	extent_node_t *node, key;
+
+	key.addr = NULL;
+	key.size = size;
+	malloc_mutex_lock(&dss_mtx);
+	node = extent_tree_szad_nsearch(&dss_chunks_szad, &key);
+	if (node != NULL) {
+		void *ret = node->addr;
+
+		/* Remove node from the tree. */
+		extent_tree_szad_remove(&dss_chunks_szad, node);
+		if (node->size == size) {
+			extent_tree_ad_remove(&dss_chunks_ad, node);
+			base_node_dealloc(node);
+		} else {
+			/*
+			 * Insert the remainder of node's address range as a
+			 * smaller chunk.  Its position within dss_chunks_ad
+			 * does not change.
+			 */
+			assert(node->size > size);
+			node->addr = (void *)((uintptr_t)node->addr + size);
+			node->size -= size;
+			extent_tree_szad_insert(&dss_chunks_szad, node);
+		}
+		malloc_mutex_unlock(&dss_mtx);
+
+		if (zero)
+			memset(ret, 0, size);
+		return (ret);
+	}
+	malloc_mutex_unlock(&dss_mtx);
+
+	return (NULL);
+}
+#endif
+
+static void *
+chunk_alloc_mmap(size_t size)
+{
+	void *ret;
+	size_t offset;
+
+	/*
+	 * Ideally, there would be a way to specify alignment to mmap() (like
+	 * NetBSD has), but in the absence of such a feature, we have to work
+	 * hard to efficiently create aligned mappings.  The reliable, but
+	 * expensive method is to create a mapping that is over-sized, then
+	 * trim the excess.  However, that always results in at least one call
+	 * to pages_unmap().
+	 *
+	 * A more optimistic approach is to try mapping precisely the right
+	 * amount, then try to append another mapping if alignment is off.  In
+	 * practice, this works out well as long as the application is not
+	 * interleaving mappings via direct mmap() calls.  If we do run into a
+	 * situation where there is an interleaved mapping and we are unable to
+	 * extend an unaligned mapping, our best option is to momentarily
+	 * revert to the reliable-but-expensive method.  This will tend to
+	 * leave a gap in the memory map that is too small to cause later
+	 * problems for the optimistic method.
+	 */
+
+	ret = pages_map(NULL, size);
+	if (ret == NULL)
+		return (NULL);
+
+	offset = CHUNK_ADDR2OFFSET(ret);
+	if (offset != 0) {
+		/* Try to extend chunk boundary. */
+		if (pages_map((void *)((uintptr_t)ret + size),
+		    chunksize - offset) == NULL) {
+			/*
+			 * Extension failed.  Clean up, then revert to the
+			 * reliable-but-expensive method.
+			 */
+			pages_unmap(ret, size);
+
+			/* Beware size_t wrap-around. */
+			if (size + chunksize <= size)
+				return NULL;
+
+			ret = pages_map(NULL, size + chunksize);
+			if (ret == NULL)
+				return (NULL);
+
+			/* Clean up unneeded leading/trailing space. */
+			offset = CHUNK_ADDR2OFFSET(ret);
+			if (offset != 0) {
+				/* Leading space. */
+				pages_unmap(ret, chunksize - offset);
+
+				ret = (void *)((uintptr_t)ret +
+				    (chunksize - offset));
+
+				/* Trailing space. */
+				pages_unmap((void *)((uintptr_t)ret + size),
+				    offset);
+			} else {
+				/* Trailing space only. */
+				pages_unmap((void *)((uintptr_t)ret + size),
+				    chunksize);
+			}
+		} else {
+			/* Clean up unneeded leading space. */
+			pages_unmap(ret, chunksize - offset);
+			ret = (void *)((uintptr_t)ret + (chunksize - offset));
+		}
+	}
+
+	return (ret);
+}
+
+static void *
+chunk_alloc(size_t size, bool zero)
+{
+	void *ret;
+
+	assert(size != 0);
+	assert((size & chunksize_mask) == 0);
+
+#ifdef MALLOC_DSS
+	if (opt_dss) {
+		ret = chunk_recycle_dss(size, zero);
+		if (ret != NULL) {
+			goto RETURN;
+		}
+
+		ret = chunk_alloc_dss(size);
+		if (ret != NULL)
+			goto RETURN;
+	}
+
+	if (opt_mmap)
+#endif
+	{
+		ret = chunk_alloc_mmap(size);
+		if (ret != NULL)
+			goto RETURN;
+	}
+
+	/* All strategies for allocation failed. */
+	ret = NULL;
+RETURN:
+#ifdef MALLOC_STATS
+	if (ret != NULL) {
+		stats_chunks.nchunks += (size / chunksize);
+		stats_chunks.curchunks += (size / chunksize);
+	}
+	if (stats_chunks.curchunks > stats_chunks.highchunks)
+		stats_chunks.highchunks = stats_chunks.curchunks;
+#endif
+
+	assert(CHUNK_ADDR2BASE(ret) == ret);
+	return (ret);
+}
+
+#ifdef MALLOC_DSS
+static extent_node_t *
+chunk_dealloc_dss_record(void *chunk, size_t size)
+{
+	extent_node_t *node, *prev, key;
+
+	key.addr = (void *)((uintptr_t)chunk + size);
+	node = extent_tree_ad_nsearch(&dss_chunks_ad, &key);
+	/* Try to coalesce forward. */
+	if (node != NULL && node->addr == key.addr) {
+		/*
+		 * Coalesce chunk with the following address range.  This does
+		 * not change the position within dss_chunks_ad, so only
+		 * remove/insert from/into dss_chunks_szad.
+		 */
+		extent_tree_szad_remove(&dss_chunks_szad, node);
+		node->addr = chunk;
+		node->size += size;
+		extent_tree_szad_insert(&dss_chunks_szad, node);
+	} else {
+		/*
+		 * Coalescing forward failed, so insert a new node.  Drop
+		 * dss_mtx during node allocation, since it is possible that a
+		 * new base chunk will be allocated.
+		 */
+		malloc_mutex_unlock(&dss_mtx);
+		node = base_node_alloc();
+		malloc_mutex_lock(&dss_mtx);
+		if (node == NULL)
+			return (NULL);
+		node->addr = chunk;
+		node->size = size;
+		extent_tree_ad_insert(&dss_chunks_ad, node);
+		extent_tree_szad_insert(&dss_chunks_szad, node);
+	}
+
+	/* Try to coalesce backward. */
+	prev = extent_tree_ad_prev(&dss_chunks_ad, node);
+	if (prev != NULL && (void *)((uintptr_t)prev->addr + prev->size) ==
+	    chunk) {
+		/*
+		 * Coalesce chunk with the previous address range.  This does
+		 * not change the position within dss_chunks_ad, so only
+		 * remove/insert node from/into dss_chunks_szad.
+		 */
+		extent_tree_szad_remove(&dss_chunks_szad, prev);
+		extent_tree_ad_remove(&dss_chunks_ad, prev);
+
+		extent_tree_szad_remove(&dss_chunks_szad, node);
+		node->addr = prev->addr;
+		node->size += prev->size;
+		extent_tree_szad_insert(&dss_chunks_szad, node);
+
+		base_node_dealloc(prev);
+	}
+
+	return (node);
+}
+
+static bool
+chunk_dealloc_dss(void *chunk, size_t size)
+{
+
+	malloc_mutex_lock(&dss_mtx);
+	if ((uintptr_t)chunk >= (uintptr_t)dss_base
+	    && (uintptr_t)chunk < (uintptr_t)dss_max) {
+		extent_node_t *node;
+
+		/* Try to coalesce with other unused chunks. */
+		node = chunk_dealloc_dss_record(chunk, size);
+		if (node != NULL) {
+			chunk = node->addr;
+			size = node->size;
+		}
+
+		/* Get the current end of the DSS. */
+		dss_max = sbrk(0);
+
+		/*
+		 * Try to shrink the DSS if this chunk is at the end of the
+		 * DSS.  The sbrk() call here is subject to a race condition
+		 * with threads that use brk(2) or sbrk(2) directly, but the
+		 * alternative would be to leak memory for the sake of poorly
+		 * designed multi-threaded programs.
+		 */
+		if ((void *)((uintptr_t)chunk + size) == dss_max
+		    && (dss_prev = sbrk(-(intptr_t)size)) == dss_max) {
+			/* Success. */
+			dss_max = (void *)((intptr_t)dss_prev - (intptr_t)size);
+
+			if (node != NULL) {
+				extent_tree_szad_remove(&dss_chunks_szad, node);
+				extent_tree_ad_remove(&dss_chunks_ad, node);
+				base_node_dealloc(node);
+			}
+			malloc_mutex_unlock(&dss_mtx);
+		} else {
+			malloc_mutex_unlock(&dss_mtx);
+			madvise(chunk, size, MADV_DONTNEED);
+		}
+
+		return (false);
+	}
+	malloc_mutex_unlock(&dss_mtx);
+
+	return (true);
+}
+#endif
+
+static void
+chunk_dealloc_mmap(void *chunk, size_t size)
+{
+
+	pages_unmap(chunk, size);
+}
+
+static void
+chunk_dealloc(void *chunk, size_t size)
+{
+
+	assert(chunk != NULL);
+	assert(CHUNK_ADDR2BASE(chunk) == chunk);
+	assert(size != 0);
+	assert((size & chunksize_mask) == 0);
+
+#ifdef MALLOC_STATS
+	stats_chunks.curchunks -= (size / chunksize);
+#endif
+
+#ifdef MALLOC_DSS
+	if (opt_dss) {
+		if (chunk_dealloc_dss(chunk, size) == false)
+			return;
+	}
+
+	if (opt_mmap)
+#endif
+		chunk_dealloc_mmap(chunk, size);
+}
+
+/*
+ * End chunk management functions.
+ */
+/******************************************************************************/
+/*
+ * Begin arena.
+ */
+
+/*
+ * Choose an arena based on a per-thread value (fast-path code, calls slow-path
+ * code if necessary).
+ */
+static inline arena_t *
+choose_arena(void)
+{
+	arena_t *ret;
+
+	/*
+	 * We can only use TLS if this is a PIC library, since for the static
+	 * library version, libc's malloc is used by TLS allocation, which
+	 * introduces a bootstrapping issue.
+	 */
+#ifndef NO_TLS
+	if (__isthreaded == false) {
+	    /* Avoid the overhead of TLS for single-threaded operation. */
+	    return (arenas[0]);
+	}
+
+	ret = arenas_map;
+	if (ret == NULL) {
+		ret = choose_arena_hard();
+		assert(ret != NULL);
+	}
+#else
+	if (__isthreaded && narenas > 1) {
+		unsigned long ind;
+
+		/*
+		 * Hash pthread_self() to one of the arenas.  There is a prime
+		 * number of arenas, so this has a reasonable chance of
+		 * working.  Even so, the hashing can be easily thwarted by
+		 * inconvenient pthread_self() values.  Without specific
+		 * knowledge of how pthread_self() calculates values, we can't
+		 * easily do much better than this.
+		 */
+		ind = (unsigned long) pthread_self() % narenas;
+
+		/*
+		 * Optimistially assume that arenas[ind] has been initialized.
+		 * At worst, we find out that some other thread has already
+		 * done so, after acquiring the lock in preparation.  Note that
+		 * this lazy locking also has the effect of lazily forcing
+		 * cache coherency; without the lock acquisition, there's no
+		 * guarantee that modification of arenas[ind] by another thread
+		 * would be seen on this CPU for an arbitrary amount of time.
+		 *
+		 * In general, this approach to modifying a synchronized value
+		 * isn't a good idea, but in this case we only ever modify the
+		 * value once, so things work out well.
+		 */
+		ret = arenas[ind];
+		if (ret == NULL) {
+			/*
+			 * Avoid races with another thread that may have already
+			 * initialized arenas[ind].
+			 */
+			malloc_spin_lock(&arenas_lock);
+			if (arenas[ind] == NULL)
+				ret = arenas_extend((unsigned)ind);
+			else
+				ret = arenas[ind];
+			malloc_spin_unlock(&arenas_lock);
+		}
+	} else
+		ret = arenas[0];
+#endif
+
+	assert(ret != NULL);
+	return (ret);
+}
+
+#ifndef NO_TLS
+/*
+ * Choose an arena based on a per-thread value (slow-path code only, called
+ * only by choose_arena()).
+ */
+static arena_t *
+choose_arena_hard(void)
+{
+	arena_t *ret;
+
+	assert(__isthreaded);
+
+#ifdef MALLOC_BALANCE
+	/* Seed the PRNG used for arena load balancing. */
+	SPRN(balance, (uint32_t)(uintptr_t)(pthread_self()));
+#endif
+
+	if (narenas > 1) {
+#ifdef MALLOC_BALANCE
+		unsigned ind;
+
+		ind = PRN(balance, narenas_2pow);
+		if ((ret = arenas[ind]) == NULL) {
+			malloc_spin_lock(&arenas_lock);
+			if ((ret = arenas[ind]) == NULL)
+				ret = arenas_extend(ind);
+			malloc_spin_unlock(&arenas_lock);
+		}
+#else
+		malloc_spin_lock(&arenas_lock);
+		if ((ret = arenas[next_arena]) == NULL)
+			ret = arenas_extend(next_arena);
+		next_arena = (next_arena + 1) % narenas;
+		malloc_spin_unlock(&arenas_lock);
+#endif
+	} else
+		ret = arenas[0];
+
+	arenas_map = ret;
+
+	return (ret);
+}
+#endif
+
+static inline int
+arena_chunk_comp(arena_chunk_t *a, arena_chunk_t *b)
+{
+	uintptr_t a_chunk = (uintptr_t)a;
+	uintptr_t b_chunk = (uintptr_t)b;
+
+	assert(a != NULL);
+	assert(b != NULL);
+
+	return ((a_chunk > b_chunk) - (a_chunk < b_chunk));
+}
+
+/* Wrap red-black tree macros in functions. */
+rb_wrap(static, arena_chunk_tree_dirty_, arena_chunk_tree_t,
+    arena_chunk_t, link_dirty, arena_chunk_comp)
+
+static inline int
+arena_run_comp(arena_chunk_map_t *a, arena_chunk_map_t *b)
+{
+	uintptr_t a_mapelm = (uintptr_t)a;
+	uintptr_t b_mapelm = (uintptr_t)b;
+
+	assert(a != NULL);
+	assert(b != NULL);
+
+	return ((a_mapelm > b_mapelm) - (a_mapelm < b_mapelm));
+}
+
+/* Wrap red-black tree macros in functions. */
+rb_wrap(static, arena_run_tree_, arena_run_tree_t, arena_chunk_map_t,
+    link, arena_run_comp)
+
+static inline int
+arena_avail_comp(arena_chunk_map_t *a, arena_chunk_map_t *b)
+{
+	int ret;
+	size_t a_size = a->bits & ~pagesize_mask;
+	size_t b_size = b->bits & ~pagesize_mask;
+
+	ret = (a_size > b_size) - (a_size < b_size);
+	if (ret == 0) {
+		uintptr_t a_mapelm, b_mapelm;
+
+		if ((a->bits & CHUNK_MAP_KEY) == 0)
+			a_mapelm = (uintptr_t)a;
+		else {
+			/*
+			 * Treat keys as though they are lower than anything
+			 * else.
+			 */
+			a_mapelm = 0;
+		}
+		b_mapelm = (uintptr_t)b;
+
+		ret = (a_mapelm > b_mapelm) - (a_mapelm < b_mapelm);
+	}
+
+	return (ret);
+}
+
+/* Wrap red-black tree macros in functions. */
+rb_wrap(static, arena_avail_tree_, arena_avail_tree_t,
+    arena_chunk_map_t, link, arena_avail_comp)
+
+static inline void *
+arena_run_reg_alloc(arena_run_t *run, arena_bin_t *bin)
+{
+	void *ret;
+	unsigned i, mask, bit, regind;
+
+	assert(run->magic == ARENA_RUN_MAGIC);
+	assert(run->regs_minelm < bin->regs_mask_nelms);
+
+	/*
+	 * Move the first check outside the loop, so that run->regs_minelm can
+	 * be updated unconditionally, without the possibility of updating it
+	 * multiple times.
+	 */
+	i = run->regs_minelm;
+	mask = run->regs_mask[i];
+	if (mask != 0) {
+		/* Usable allocation found. */
+		bit = ffs((int)mask) - 1;
+
+		regind = ((i << (SIZEOF_INT_2POW + 3)) + bit);
+		assert(regind < bin->nregs);
+		ret = (void *)(((uintptr_t)run) + bin->reg0_offset
+		    + (bin->reg_size * regind));
+
+		/* Clear bit. */
+		mask ^= (1U << bit);
+		run->regs_mask[i] = mask;
+
+		return (ret);
+	}
+
+	for (i++; i < bin->regs_mask_nelms; i++) {
+		mask = run->regs_mask[i];
+		if (mask != 0) {
+			/* Usable allocation found. */
+			bit = ffs((int)mask) - 1;
+
+			regind = ((i << (SIZEOF_INT_2POW + 3)) + bit);
+			assert(regind < bin->nregs);
+			ret = (void *)(((uintptr_t)run) + bin->reg0_offset
+			    + (bin->reg_size * regind));
+
+			/* Clear bit. */
+			mask ^= (1U << bit);
+			run->regs_mask[i] = mask;
+
+			/*
+			 * Make a note that nothing before this element
+			 * contains a free region.
+			 */
+			run->regs_minelm = i; /* Low payoff: + (mask == 0); */
+
+			return (ret);
+		}
+	}
+	/* Not reached. */
+	assert(0);
+	return (NULL);
+}
+
+static inline void
+arena_run_reg_dalloc(arena_run_t *run, arena_bin_t *bin, void *ptr, size_t size)
+{
+	unsigned diff, regind, elm, bit;
+
+	assert(run->magic == ARENA_RUN_MAGIC);
+
+	/*
+	 * Avoid doing division with a variable divisor if possible.  Using
+	 * actual division here can reduce allocator throughput by over 20%!
+	 */
+	diff = (unsigned)((uintptr_t)ptr - (uintptr_t)run - bin->reg0_offset);
+	if ((size & (size - 1)) == 0) {
+		/*
+		 * log2_table allows fast division of a power of two in the
+		 * [1..128] range.
+		 *
+		 * (x / divisor) becomes (x >> log2_table[divisor - 1]).
+		 */
+		static const unsigned char log2_table[] = {
+		    0, 1, 0, 2, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 4,
+		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5,
+		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6,
+		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7
+		};
+
+		if (size <= 128)
+			regind = (diff >> log2_table[size - 1]);
+		else if (size <= 32768)
+			regind = diff >> (8 + log2_table[(size >> 8) - 1]);
+		else
+			regind = diff / size;
+	} else if (size < qspace_max) {
+		/*
+		 * To divide by a number D that is not a power of two we
+		 * multiply by (2^21 / D) and then right shift by 21 positions.
+		 *
+		 *   X / D
+		 *
+		 * becomes
+		 *
+		 *   (X * qsize_invs[(D >> QUANTUM_2POW) - 3])
+		 *       >> SIZE_INV_SHIFT
+		 *
+		 * We can omit the first three elements, because we never
+		 * divide by 0, and QUANTUM and 2*QUANTUM are both powers of
+		 * two, which are handled above.
+		 */
+#define	SIZE_INV_SHIFT 21
+#define	QSIZE_INV(s) (((1U << SIZE_INV_SHIFT) / (s << QUANTUM_2POW)) + 1)
+		static const unsigned qsize_invs[] = {
+		    QSIZE_INV(3),
+		    QSIZE_INV(4), QSIZE_INV(5), QSIZE_INV(6), QSIZE_INV(7)
+#if (QUANTUM_2POW < 4)
+		    ,
+		    QSIZE_INV(8), QSIZE_INV(9), QSIZE_INV(10), QSIZE_INV(11),
+		    QSIZE_INV(12),QSIZE_INV(13), QSIZE_INV(14), QSIZE_INV(15)
+#endif
+		};
+		assert(QUANTUM * (((sizeof(qsize_invs)) / sizeof(unsigned)) + 3)
+		    >= (1U << QSPACE_MAX_2POW_DEFAULT));
+
+		if (size <= (((sizeof(qsize_invs) / sizeof(unsigned)) + 2) <<
+		    QUANTUM_2POW)) {
+			regind = qsize_invs[(size >> QUANTUM_2POW) - 3] * diff;
+			regind >>= SIZE_INV_SHIFT;
+		} else
+			regind = diff / size;
+#undef QSIZE_INV
+	} else if (size < cspace_max) {
+#define	CSIZE_INV(s) (((1U << SIZE_INV_SHIFT) / (s << CACHELINE_2POW)) + 1)
+		static const unsigned csize_invs[] = {
+		    CSIZE_INV(3),
+		    CSIZE_INV(4), CSIZE_INV(5), CSIZE_INV(6), CSIZE_INV(7)
+		};
+		assert(CACHELINE * (((sizeof(csize_invs)) / sizeof(unsigned)) +
+		    3) >= (1U << CSPACE_MAX_2POW_DEFAULT));
+
+		if (size <= (((sizeof(csize_invs) / sizeof(unsigned)) + 2) <<
+		    CACHELINE_2POW)) {
+			regind = csize_invs[(size >> CACHELINE_2POW) - 3] *
+			    diff;
+			regind >>= SIZE_INV_SHIFT;
+		} else
+			regind = diff / size;
+#undef CSIZE_INV
+	} else {
+#define	SSIZE_INV(s) (((1U << SIZE_INV_SHIFT) / (s << SUBPAGE_2POW)) + 1)
+		static const unsigned ssize_invs[] = {
+		    SSIZE_INV(3),
+		    SSIZE_INV(4), SSIZE_INV(5), SSIZE_INV(6), SSIZE_INV(7),
+		    SSIZE_INV(8), SSIZE_INV(9), SSIZE_INV(10), SSIZE_INV(11),
+		    SSIZE_INV(12), SSIZE_INV(13), SSIZE_INV(14), SSIZE_INV(15)
+#if (PAGESIZE_2POW == 13)
+		    ,
+		    SSIZE_INV(16), SSIZE_INV(17), SSIZE_INV(18), SSIZE_INV(19),
+		    SSIZE_INV(20), SSIZE_INV(21), SSIZE_INV(22), SSIZE_INV(23),
+		    SSIZE_INV(24), SSIZE_INV(25), SSIZE_INV(26), SSIZE_INV(27),
+		    SSIZE_INV(28), SSIZE_INV(29), SSIZE_INV(29), SSIZE_INV(30)
+#endif
+		};
+		assert(SUBPAGE * (((sizeof(ssize_invs)) / sizeof(unsigned)) + 3)
+		    >= (1U << PAGESIZE_2POW));
+
+		if (size < (((sizeof(ssize_invs) / sizeof(unsigned)) + 2) <<
+		    SUBPAGE_2POW)) {
+			regind = ssize_invs[(size >> SUBPAGE_2POW) - 3] * diff;
+			regind >>= SIZE_INV_SHIFT;
+		} else
+			regind = diff / size;
+#undef SSIZE_INV
+	}
+#undef SIZE_INV_SHIFT
+	assert(diff == regind * size);
+	assert(regind < bin->nregs);
+
+	elm = regind >> (SIZEOF_INT_2POW + 3);
+	if (elm < run->regs_minelm)
+		run->regs_minelm = elm;
+	bit = regind - (elm << (SIZEOF_INT_2POW + 3));
+	assert((run->regs_mask[elm] & (1U << bit)) == 0);
+	run->regs_mask[elm] |= (1U << bit);
+}
+
+static void
+arena_run_split(arena_t *arena, arena_run_t *run, size_t size, bool large,
+    bool zero)
+{
+	arena_chunk_t *chunk;
+	size_t old_ndirty, run_ind, total_pages, need_pages, rem_pages, i;
+
+	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run);
+	old_ndirty = chunk->ndirty;
+	run_ind = (unsigned)(((uintptr_t)run - (uintptr_t)chunk)
+	    >> pagesize_2pow);
+	total_pages = (chunk->map[run_ind].bits & ~pagesize_mask) >>
+	    pagesize_2pow;
+	need_pages = (size >> pagesize_2pow);
+	assert(need_pages > 0);
+	assert(need_pages <= total_pages);
+	rem_pages = total_pages - need_pages;
+
+	arena_avail_tree_remove(&arena->runs_avail, &chunk->map[run_ind]);
+
+	/* Keep track of trailing unused pages for later use. */
+	if (rem_pages > 0) {
+		chunk->map[run_ind+need_pages].bits = (rem_pages <<
+		    pagesize_2pow) | (chunk->map[run_ind+need_pages].bits &
+		    pagesize_mask);
+		chunk->map[run_ind+total_pages-1].bits = (rem_pages <<
+		    pagesize_2pow) | (chunk->map[run_ind+total_pages-1].bits &
+		    pagesize_mask);
+		arena_avail_tree_insert(&arena->runs_avail,
+		    &chunk->map[run_ind+need_pages]);
+	}
+
+	for (i = 0; i < need_pages; i++) {
+		/* Zero if necessary. */
+		if (zero) {
+			if ((chunk->map[run_ind + i].bits & CHUNK_MAP_ZEROED)
+			    == 0) {
+				memset((void *)((uintptr_t)chunk + ((run_ind
+				    + i) << pagesize_2pow)), 0, pagesize);
+				/* CHUNK_MAP_ZEROED is cleared below. */
+			}
+		}
+
+		/* Update dirty page accounting. */
+		if (chunk->map[run_ind + i].bits & CHUNK_MAP_DIRTY) {
+			chunk->ndirty--;
+			arena->ndirty--;
+			/* CHUNK_MAP_DIRTY is cleared below. */
+		}
+
+		/* Initialize the chunk map. */
+		if (large) {
+			chunk->map[run_ind + i].bits = CHUNK_MAP_LARGE
+			    | CHUNK_MAP_ALLOCATED;
+		} else {
+			chunk->map[run_ind + i].bits = (size_t)run
+			    | CHUNK_MAP_ALLOCATED;
+		}
+	}
+
+	/*
+	 * Set the run size only in the first element for large runs.  This is
+	 * primarily a debugging aid, since the lack of size info for trailing
+	 * pages only matters if the application tries to operate on an
+	 * interior pointer.
+	 */
+	if (large)
+		chunk->map[run_ind].bits |= size;
+
+	if (chunk->ndirty == 0 && old_ndirty > 0)
+		arena_chunk_tree_dirty_remove(&arena->chunks_dirty, chunk);
+}
+
+static arena_chunk_t *
+arena_chunk_alloc(arena_t *arena)
+{
+	arena_chunk_t *chunk;
+	size_t i;
+
+	if (arena->spare != NULL) {
+		chunk = arena->spare;
+		arena->spare = NULL;
+	} else {
+		chunk = (arena_chunk_t *)chunk_alloc(chunksize, true);
+		if (chunk == NULL)
+			return (NULL);
+#ifdef MALLOC_STATS
+		arena->stats.mapped += chunksize;
+#endif
+
+		chunk->arena = arena;
+
+		/*
+		 * Claim that no pages are in use, since the header is merely
+		 * overhead.
+		 */
+		chunk->ndirty = 0;
+
+		/*
+		 * Initialize the map to contain one maximal free untouched run.
+		 */
+		for (i = 0; i < arena_chunk_header_npages; i++)
+			chunk->map[i].bits = 0;
+		chunk->map[i].bits = arena_maxclass | CHUNK_MAP_ZEROED;
+		for (i++; i < chunk_npages-1; i++) {
+			chunk->map[i].bits = CHUNK_MAP_ZEROED;
+		}
+		chunk->map[chunk_npages-1].bits = arena_maxclass |
+		    CHUNK_MAP_ZEROED;
+	}
+
+	/* Insert the run into the runs_avail tree. */
+	arena_avail_tree_insert(&arena->runs_avail,
+	    &chunk->map[arena_chunk_header_npages]);
+
+	return (chunk);
+}
+
+static void
+arena_chunk_dealloc(arena_t *arena, arena_chunk_t *chunk)
+{
+
+	if (arena->spare != NULL) {
+		if (arena->spare->ndirty > 0) {
+			arena_chunk_tree_dirty_remove(
+			    &chunk->arena->chunks_dirty, arena->spare);
+			arena->ndirty -= arena->spare->ndirty;
+		}
+		chunk_dealloc((void *)arena->spare, chunksize);
+#ifdef MALLOC_STATS
+		arena->stats.mapped -= chunksize;
+#endif
+	}
+
+	/*
+	 * Remove run from runs_avail, regardless of whether this chunk
+	 * will be cached, so that the arena does not use it.  Dirty page
+	 * flushing only uses the chunks_dirty tree, so leaving this chunk in
+	 * the chunks_* trees is sufficient for that purpose.
+	 */
+	arena_avail_tree_remove(&arena->runs_avail,
+	    &chunk->map[arena_chunk_header_npages]);
+
+	arena->spare = chunk;
+}
+
+static arena_run_t *
+arena_run_alloc(arena_t *arena, size_t size, bool large, bool zero)
+{
+	arena_chunk_t *chunk;
+	arena_run_t *run;
+	arena_chunk_map_t *mapelm, key;
+
+	assert(size <= arena_maxclass);
+	assert((size & pagesize_mask) == 0);
+
+	/* Search the arena's chunks for the lowest best fit. */
+	key.bits = size | CHUNK_MAP_KEY;
+	mapelm = arena_avail_tree_nsearch(&arena->runs_avail, &key);
+	if (mapelm != NULL) {
+		arena_chunk_t *run_chunk = CHUNK_ADDR2BASE(mapelm);
+		size_t pageind = ((uintptr_t)mapelm - (uintptr_t)run_chunk->map)
+		    / sizeof(arena_chunk_map_t);
+
+		run = (arena_run_t *)((uintptr_t)run_chunk + (pageind
+		    << pagesize_2pow));
+		arena_run_split(arena, run, size, large, zero);
+		return (run);
+	}
+
+	/*
+	 * No usable runs.  Create a new chunk from which to allocate the run.
+	 */
+	chunk = arena_chunk_alloc(arena);
+	if (chunk == NULL)
+		return (NULL);
+	run = (arena_run_t *)((uintptr_t)chunk + (arena_chunk_header_npages <<
+	    pagesize_2pow));
+	/* Update page map. */
+	arena_run_split(arena, run, size, large, zero);
+	return (run);
+}
+
+static void
+arena_purge(arena_t *arena)
+{
+	arena_chunk_t *chunk;
+	size_t i, npages;
+#ifdef MALLOC_DEBUG
+	size_t ndirty = 0;
+
+	rb_foreach_begin(arena_chunk_t, link_dirty, &arena->chunks_dirty,
+	    chunk) {
+		ndirty += chunk->ndirty;
+	} rb_foreach_end(arena_chunk_t, link_dirty, &arena->chunks_dirty, chunk)
+	assert(ndirty == arena->ndirty);
+#endif
+	assert(arena->ndirty > opt_dirty_max);
+
+#ifdef MALLOC_STATS
+	arena->stats.npurge++;
+#endif
+
+	/*
+	 * Iterate downward through chunks until enough dirty memory has been
+	 * purged.  Terminate as soon as possible in order to minimize the
+	 * number of system calls, even if a chunk has only been partially
+	 * purged.
+	 */
+	while (arena->ndirty > (opt_dirty_max >> 1)) {
+		chunk = arena_chunk_tree_dirty_last(&arena->chunks_dirty);
+		assert(chunk != NULL);
+
+		for (i = chunk_npages - 1; chunk->ndirty > 0; i--) {
+			assert(i >= arena_chunk_header_npages);
+
+			if (chunk->map[i].bits & CHUNK_MAP_DIRTY) {
+				chunk->map[i].bits ^= CHUNK_MAP_DIRTY;
+				/* Find adjacent dirty run(s). */
+				for (npages = 1; i > arena_chunk_header_npages
+				    && (chunk->map[i - 1].bits &
+				    CHUNK_MAP_DIRTY); npages++) {
+					i--;
+					chunk->map[i].bits ^= CHUNK_MAP_DIRTY;
+				}
+				chunk->ndirty -= npages;
+				arena->ndirty -= npages;
+
+				madvise((void *)((uintptr_t)chunk + (i <<
+				    pagesize_2pow)), (npages << pagesize_2pow),
+				    MADV_DONTNEED);
+#ifdef MALLOC_STATS
+				arena->stats.nmadvise++;
+				arena->stats.purged += npages;
+#endif
+				if (arena->ndirty <= (opt_dirty_max >> 1))
+					break;
+			}
+		}
+
+		if (chunk->ndirty == 0) {
+			arena_chunk_tree_dirty_remove(&arena->chunks_dirty,
+			    chunk);
+		}
+	}
+}
+
+static void
+arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty)
+{
+	arena_chunk_t *chunk;
+	size_t size, run_ind, run_pages;
+
+	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run);
+	run_ind = (size_t)(((uintptr_t)run - (uintptr_t)chunk)
+	    >> pagesize_2pow);
+	assert(run_ind >= arena_chunk_header_npages);
+	assert(run_ind < chunk_npages);
+	if ((chunk->map[run_ind].bits & CHUNK_MAP_LARGE) != 0)
+		size = chunk->map[run_ind].bits & ~pagesize_mask;
+	else
+		size = run->bin->run_size;
+	run_pages = (size >> pagesize_2pow);
+
+	/* Mark pages as unallocated in the chunk map. */
+	if (dirty) {
+		size_t i;
+
+		for (i = 0; i < run_pages; i++) {
+			assert((chunk->map[run_ind + i].bits & CHUNK_MAP_DIRTY)
+			    == 0);
+			chunk->map[run_ind + i].bits = CHUNK_MAP_DIRTY;
+		}
+
+		if (chunk->ndirty == 0) {
+			arena_chunk_tree_dirty_insert(&arena->chunks_dirty,
+			    chunk);
+		}
+		chunk->ndirty += run_pages;
+		arena->ndirty += run_pages;
+	} else {
+		size_t i;
+
+		for (i = 0; i < run_pages; i++) {
+			chunk->map[run_ind + i].bits &= ~(CHUNK_MAP_LARGE |
+			    CHUNK_MAP_ALLOCATED);
+		}
+	}
+	chunk->map[run_ind].bits = size | (chunk->map[run_ind].bits &
+	    pagesize_mask);
+	chunk->map[run_ind+run_pages-1].bits = size |
+	    (chunk->map[run_ind+run_pages-1].bits & pagesize_mask);
+
+	/* Try to coalesce forward. */
+	if (run_ind + run_pages < chunk_npages &&
+	    (chunk->map[run_ind+run_pages].bits & CHUNK_MAP_ALLOCATED) == 0) {
+		size_t nrun_size = chunk->map[run_ind+run_pages].bits &
+		    ~pagesize_mask;
+
+		/*
+		 * Remove successor from runs_avail; the coalesced run is
+		 * inserted later.
+		 */
+		arena_avail_tree_remove(&arena->runs_avail,
+		    &chunk->map[run_ind+run_pages]);
+
+		size += nrun_size;
+		run_pages = size >> pagesize_2pow;
+
+		assert((chunk->map[run_ind+run_pages-1].bits & ~pagesize_mask)
+		    == nrun_size);
+		chunk->map[run_ind].bits = size | (chunk->map[run_ind].bits &
+		    pagesize_mask);
+		chunk->map[run_ind+run_pages-1].bits = size |
+		    (chunk->map[run_ind+run_pages-1].bits & pagesize_mask);
+	}
+
+	/* Try to coalesce backward. */
+	if (run_ind > arena_chunk_header_npages && (chunk->map[run_ind-1].bits &
+	    CHUNK_MAP_ALLOCATED) == 0) {
+		size_t prun_size = chunk->map[run_ind-1].bits & ~pagesize_mask;
+
+		run_ind -= prun_size >> pagesize_2pow;
+
+		/*
+		 * Remove predecessor from runs_avail; the coalesced run is
+		 * inserted later.
+		 */
+		arena_avail_tree_remove(&arena->runs_avail,
+		    &chunk->map[run_ind]);
+
+		size += prun_size;
+		run_pages = size >> pagesize_2pow;
+
+		assert((chunk->map[run_ind].bits & ~pagesize_mask) ==
+		    prun_size);
+		chunk->map[run_ind].bits = size | (chunk->map[run_ind].bits &
+		    pagesize_mask);
+		chunk->map[run_ind+run_pages-1].bits = size |
+		    (chunk->map[run_ind+run_pages-1].bits & pagesize_mask);
+	}
+
+	/* Insert into runs_avail, now that coalescing is complete. */
+	arena_avail_tree_insert(&arena->runs_avail, &chunk->map[run_ind]);
+
+	/* Deallocate chunk if it is now completely unused. */
+	if ((chunk->map[arena_chunk_header_npages].bits & (~pagesize_mask |
+	    CHUNK_MAP_ALLOCATED)) == arena_maxclass)
+		arena_chunk_dealloc(arena, chunk);
+
+	/* Enforce opt_dirty_max. */
+	if (arena->ndirty > opt_dirty_max)
+		arena_purge(arena);
+}
+
+static void
+arena_run_trim_head(arena_t *arena, arena_chunk_t *chunk, arena_run_t *run,
+    size_t oldsize, size_t newsize)
+{
+	size_t pageind = ((uintptr_t)run - (uintptr_t)chunk) >> pagesize_2pow;
+	size_t head_npages = (oldsize - newsize) >> pagesize_2pow;
+
+	assert(oldsize > newsize);
+
+	/*
+	 * Update the chunk map so that arena_run_dalloc() can treat the
+	 * leading run as separately allocated.
+	 */
+	chunk->map[pageind].bits = (oldsize - newsize) | CHUNK_MAP_LARGE |
+	    CHUNK_MAP_ALLOCATED;
+	chunk->map[pageind+head_npages].bits = newsize | CHUNK_MAP_LARGE |
+	    CHUNK_MAP_ALLOCATED;
+
+	arena_run_dalloc(arena, run, false);
+}
+
+static void
+arena_run_trim_tail(arena_t *arena, arena_chunk_t *chunk, arena_run_t *run,
+    size_t oldsize, size_t newsize, bool dirty)
+{
+	size_t pageind = ((uintptr_t)run - (uintptr_t)chunk) >> pagesize_2pow;
+	size_t npages = newsize >> pagesize_2pow;
+
+	assert(oldsize > newsize);
+
+	/*
+	 * Update the chunk map so that arena_run_dalloc() can treat the
+	 * trailing run as separately allocated.
+	 */
+	chunk->map[pageind].bits = newsize | CHUNK_MAP_LARGE |
+	    CHUNK_MAP_ALLOCATED;
+	chunk->map[pageind+npages].bits = (oldsize - newsize) | CHUNK_MAP_LARGE
+	    | CHUNK_MAP_ALLOCATED;
+
+	arena_run_dalloc(arena, (arena_run_t *)((uintptr_t)run + newsize),
+	    dirty);
+}
+
+static arena_run_t *
+arena_bin_nonfull_run_get(arena_t *arena, arena_bin_t *bin)
+{
+	arena_chunk_map_t *mapelm;
+	arena_run_t *run;
+	unsigned i, remainder;
+
+	/* Look for a usable run. */
+	mapelm = arena_run_tree_first(&bin->runs);
+	if (mapelm != NULL) {
+		/* run is guaranteed to have available space. */
+		arena_run_tree_remove(&bin->runs, mapelm);
+		run = (arena_run_t *)(mapelm->bits & ~pagesize_mask);
+#ifdef MALLOC_STATS
+		bin->stats.reruns++;
+#endif
+		return (run);
+	}
+	/* No existing runs have any space available. */
+
+	/* Allocate a new run. */
+	run = arena_run_alloc(arena, bin->run_size, false, false);
+	if (run == NULL)
+		return (NULL);
+
+	/* Initialize run internals. */
+	run->bin = bin;
+
+	for (i = 0; i < bin->regs_mask_nelms - 1; i++)
+		run->regs_mask[i] = UINT_MAX;
+	remainder = bin->nregs & ((1U << (SIZEOF_INT_2POW + 3)) - 1);
+	if (remainder == 0)
+		run->regs_mask[i] = UINT_MAX;
+	else {
+		/* The last element has spare bits that need to be unset. */
+		run->regs_mask[i] = (UINT_MAX >> ((1U << (SIZEOF_INT_2POW + 3))
+		    - remainder));
+	}
+
+	run->regs_minelm = 0;
+
+	run->nfree = bin->nregs;
+#ifdef MALLOC_DEBUG
+	run->magic = ARENA_RUN_MAGIC;
+#endif
+
+#ifdef MALLOC_STATS
+	bin->stats.nruns++;
+	bin->stats.curruns++;
+	if (bin->stats.curruns > bin->stats.highruns)
+		bin->stats.highruns = bin->stats.curruns;
+#endif
+	return (run);
+}
+
+/* bin->runcur must have space available before this function is called. */
+static inline void *
+arena_bin_malloc_easy(arena_t *arena, arena_bin_t *bin, arena_run_t *run)
+{
+	void *ret;
+
+	assert(run->magic == ARENA_RUN_MAGIC);
+	assert(run->nfree > 0);
+
+	ret = arena_run_reg_alloc(run, bin);
+	assert(ret != NULL);
+	run->nfree--;
+
+	return (ret);
+}
+
+/* Re-fill bin->runcur, then call arena_bin_malloc_easy(). */
+static void *
+arena_bin_malloc_hard(arena_t *arena, arena_bin_t *bin)
+{
+
+	bin->runcur = arena_bin_nonfull_run_get(arena, bin);
+	if (bin->runcur == NULL)
+		return (NULL);
+	assert(bin->runcur->magic == ARENA_RUN_MAGIC);
+	assert(bin->runcur->nfree > 0);
+
+	return (arena_bin_malloc_easy(arena, bin, bin->runcur));
+}
+
+/*
+ * Calculate bin->run_size such that it meets the following constraints:
+ *
+ *   *) bin->run_size >= min_run_size
+ *   *) bin->run_size <= arena_maxclass
+ *   *) bin->run_size <= RUN_MAX_SMALL
+ *   *) run header overhead <= RUN_MAX_OVRHD (or header overhead relaxed).
+ *
+ * bin->nregs, bin->regs_mask_nelms, and bin->reg0_offset are
+ * also calculated here, since these settings are all interdependent.
+ */
+static size_t
+arena_bin_run_size_calc(arena_bin_t *bin, size_t min_run_size)
+{
+	size_t try_run_size, good_run_size;
+	unsigned good_nregs, good_mask_nelms, good_reg0_offset;
+	unsigned try_nregs, try_mask_nelms, try_reg0_offset;
+
+	assert(min_run_size >= pagesize);
+	assert(min_run_size <= arena_maxclass);
+	assert(min_run_size <= RUN_MAX_SMALL);
+
+	/*
+	 * Calculate known-valid settings before entering the run_size
+	 * expansion loop, so that the first part of the loop always copies
+	 * valid settings.
+	 *
+	 * The do..while loop iteratively reduces the number of regions until
+	 * the run header and the regions no longer overlap.  A closed formula
+	 * would be quite messy, since there is an interdependency between the
+	 * header's mask length and the number of regions.
+	 */
+	try_run_size = min_run_size;
+	try_nregs = ((try_run_size - sizeof(arena_run_t)) / bin->reg_size)
+	    + 1; /* Counter-act try_nregs-- in loop. */
+	do {
+		try_nregs--;
+		try_mask_nelms = (try_nregs >> (SIZEOF_INT_2POW + 3)) +
+		    ((try_nregs & ((1U << (SIZEOF_INT_2POW + 3)) - 1)) ? 1 : 0);
+		try_reg0_offset = try_run_size - (try_nregs * bin->reg_size);
+	} while (sizeof(arena_run_t) + (sizeof(unsigned) * (try_mask_nelms - 1))
+	    > try_reg0_offset);
+
+	/* run_size expansion loop. */
+	do {
+		/*
+		 * Copy valid settings before trying more aggressive settings.
+		 */
+		good_run_size = try_run_size;
+		good_nregs = try_nregs;
+		good_mask_nelms = try_mask_nelms;
+		good_reg0_offset = try_reg0_offset;
+
+		/* Try more aggressive settings. */
+		try_run_size += pagesize;
+		try_nregs = ((try_run_size - sizeof(arena_run_t)) /
+		    bin->reg_size) + 1; /* Counter-act try_nregs-- in loop. */
+		do {
+			try_nregs--;
+			try_mask_nelms = (try_nregs >> (SIZEOF_INT_2POW + 3)) +
+			    ((try_nregs & ((1U << (SIZEOF_INT_2POW + 3)) - 1)) ?
+			    1 : 0);
+			try_reg0_offset = try_run_size - (try_nregs *
+			    bin->reg_size);
+		} while (sizeof(arena_run_t) + (sizeof(unsigned) *
+		    (try_mask_nelms - 1)) > try_reg0_offset);
+	} while (try_run_size <= arena_maxclass && try_run_size <= RUN_MAX_SMALL
+	    && RUN_MAX_OVRHD * (bin->reg_size << 3) > RUN_MAX_OVRHD_RELAX
+	    && (try_reg0_offset << RUN_BFP) > RUN_MAX_OVRHD * try_run_size);
+
+	assert(sizeof(arena_run_t) + (sizeof(unsigned) * (good_mask_nelms - 1))
+	    <= good_reg0_offset);
+	assert((good_mask_nelms << (SIZEOF_INT_2POW + 3)) >= good_nregs);
+
+	/* Copy final settings. */
+	bin->run_size = good_run_size;
+	bin->nregs = good_nregs;
+	bin->regs_mask_nelms = good_mask_nelms;
+	bin->reg0_offset = good_reg0_offset;
+
+	return (good_run_size);
+}
+
+#ifdef MALLOC_BALANCE
+static inline void
+arena_lock_balance(arena_t *arena)
+{
+	unsigned contention;
+
+	contention = malloc_spin_lock(&arena->lock);
+	if (narenas > 1) {
+		/*
+		 * Calculate the exponentially averaged contention for this
+		 * arena.  Due to integer math always rounding down, this value
+		 * decays somewhat faster than normal.
+		 */
+		arena->contention = (((uint64_t)arena->contention
+		    * (uint64_t)((1U << BALANCE_ALPHA_INV_2POW)-1))
+		    + (uint64_t)contention) >> BALANCE_ALPHA_INV_2POW;
+		if (arena->contention >= opt_balance_threshold)
+			arena_lock_balance_hard(arena);
+	}
+}
+
+static void
+arena_lock_balance_hard(arena_t *arena)
+{
+	uint32_t ind;
+
+	arena->contention = 0;
+#ifdef MALLOC_STATS
+	arena->stats.nbalance++;
+#endif
+	ind = PRN(balance, narenas_2pow);
+	if (arenas[ind] != NULL)
+		arenas_map = arenas[ind];
+	else {
+		malloc_spin_lock(&arenas_lock);
+		if (arenas[ind] != NULL)
+			arenas_map = arenas[ind];
+		else
+			arenas_map = arenas_extend(ind);
+		malloc_spin_unlock(&arenas_lock);
+	}
+}
+#endif
+
+#ifdef MALLOC_MAG
+static inline void *
+mag_alloc(mag_t *mag)
+{
+
+	if (mag->nrounds == 0)
+		return (NULL);
+	mag->nrounds--;
+
+	return (mag->rounds[mag->nrounds]);
+}
+
+static void
+mag_load(mag_t *mag)
+{
+	arena_t *arena;
+	arena_bin_t *bin;
+	arena_run_t *run;
+	void *round;
+	size_t i;
+
+	arena = choose_arena();
+	bin = &arena->bins[mag->binind];
+#ifdef MALLOC_BALANCE
+	arena_lock_balance(arena);
+#else
+	malloc_spin_lock(&arena->lock);
+#endif
+	for (i = mag->nrounds; i < max_rounds; i++) {
+		if ((run = bin->runcur) != NULL && run->nfree > 0)
+			round = arena_bin_malloc_easy(arena, bin, run);
+		else
+			round = arena_bin_malloc_hard(arena, bin);
+		if (round == NULL)
+			break;
+		mag->rounds[i] = round;
+	}
+#ifdef MALLOC_STATS
+	bin->stats.nmags++;
+	arena->stats.nmalloc_small += (i - mag->nrounds);
+	arena->stats.allocated_small += (i - mag->nrounds) * bin->reg_size;
+#endif
+	malloc_spin_unlock(&arena->lock);
+	mag->nrounds = i;
+}
+
+static inline void *
+mag_rack_alloc(mag_rack_t *rack, size_t size, bool zero)
+{
+	void *ret;
+	bin_mags_t *bin_mags;
+	mag_t *mag;
+	size_t binind;
+
+	binind = size2bin[size];
+	assert(binind < nbins);
+	bin_mags = &rack->bin_mags[binind];
+
+	mag = bin_mags->curmag;
+	if (mag == NULL) {
+		/* Create an initial magazine for this size class. */
+		assert(bin_mags->sparemag == NULL);
+		mag = mag_create(choose_arena(), binind);
+		if (mag == NULL)
+			return (NULL);
+		bin_mags->curmag = mag;
+		mag_load(mag);
+	}
+
+	ret = mag_alloc(mag);
+	if (ret == NULL) {
+		if (bin_mags->sparemag != NULL) {
+			if (bin_mags->sparemag->nrounds > 0) {
+				/* Swap magazines. */
+				bin_mags->curmag = bin_mags->sparemag;
+				bin_mags->sparemag = mag;
+				mag = bin_mags->curmag;
+			} else {
+				/* Reload the current magazine. */
+				mag_load(mag);
+			}
+		} else {
+			/* Create a second magazine. */
+			mag = mag_create(choose_arena(), binind);
+			if (mag == NULL)
+				return (NULL);
+			mag_load(mag);
+			bin_mags->sparemag = bin_mags->curmag;
+			bin_mags->curmag = mag;
+		}
+		ret = mag_alloc(mag);
+		if (ret == NULL)
+			return (NULL);
+	}
+
+	if (zero == false) {
+		if (opt_junk)
+			memset(ret, 0xa5, size);
+		else if (opt_zero)
+			memset(ret, 0, size);
+	} else
+		memset(ret, 0, size);
+
+	return (ret);
+}
+#endif
+
+static inline void *
+arena_malloc_small(arena_t *arena, size_t size, bool zero)
+{
+	void *ret;
+	arena_bin_t *bin;
+	arena_run_t *run;
+	size_t binind;
+
+	binind = size2bin[size];
+	assert(binind < nbins);
+	bin = &arena->bins[binind];
+	size = bin->reg_size;
+
+#ifdef MALLOC_BALANCE
+	arena_lock_balance(arena);
+#else
+	malloc_spin_lock(&arena->lock);
+#endif
+	if ((run = bin->runcur) != NULL && run->nfree > 0)
+		ret = arena_bin_malloc_easy(arena, bin, run);
+	else
+		ret = arena_bin_malloc_hard(arena, bin);
+
+	if (ret == NULL) {
+		malloc_spin_unlock(&arena->lock);
+		return (NULL);
+	}
+
+#ifdef MALLOC_STATS
+	bin->stats.nrequests++;
+	arena->stats.nmalloc_small++;
+	arena->stats.allocated_small += size;
+#endif
+	malloc_spin_unlock(&arena->lock);
+
+	if (zero == false) {
+		if (opt_junk)
+			memset(ret, 0xa5, size);
+		else if (opt_zero)
+			memset(ret, 0, size);
+	} else
+		memset(ret, 0, size);
+
+	return (ret);
+}
+
+static void *
+arena_malloc_large(arena_t *arena, size_t size, bool zero)
+{
+	void *ret;
+
+	/* Large allocation. */
+	size = PAGE_CEILING(size);
+#ifdef MALLOC_BALANCE
+	arena_lock_balance(arena);
+#else
+	malloc_spin_lock(&arena->lock);
+#endif
+	ret = (void *)arena_run_alloc(arena, size, true, zero);
+	if (ret == NULL) {
+		malloc_spin_unlock(&arena->lock);
+		return (NULL);
+	}
+#ifdef MALLOC_STATS
+	arena->stats.nmalloc_large++;
+	arena->stats.allocated_large += size;
+#endif
+	malloc_spin_unlock(&arena->lock);
+
+	if (zero == false) {
+		if (opt_junk)
+			memset(ret, 0xa5, size);
+		else if (opt_zero)
+			memset(ret, 0, size);
+	}
+
+	return (ret);
+}
+
+static inline void *
+arena_malloc(arena_t *arena, size_t size, bool zero)
+{
+
+	assert(arena != NULL);
+	assert(arena->magic == ARENA_MAGIC);
+	assert(size != 0);
+	assert(QUANTUM_CEILING(size) <= arena_maxclass);
+
+	if (size <= bin_maxclass) {
+#ifdef MALLOC_MAG
+		if (__isthreaded && opt_mag) {
+			mag_rack_t *rack = mag_rack;
+			if (rack == NULL) {
+				rack = mag_rack_create(arena);
+				if (rack == NULL)
+					return (NULL);
+				mag_rack = rack;
+			}
+			return (mag_rack_alloc(rack, size, zero));
+		} else
+#endif
+			return (arena_malloc_small(arena, size, zero));
+	} else
+		return (arena_malloc_large(arena, size, zero));
+}
+
+static inline void *
+imalloc(size_t size)
+{
+
+	assert(size != 0);
+
+	if (size <= arena_maxclass)
+		return (arena_malloc(choose_arena(), size, false));
+	else
+		return (huge_malloc(size, false));
+}
+
+static inline void *
+icalloc(size_t size)
+{
+
+	if (size <= arena_maxclass)
+		return (arena_malloc(choose_arena(), size, true));
+	else
+		return (huge_malloc(size, true));
+}
+
+/* Only handles large allocations that require more than page alignment. */
+static void *
+arena_palloc(arena_t *arena, size_t alignment, size_t size, size_t alloc_size)
+{
+	void *ret;
+	size_t offset;
+	arena_chunk_t *chunk;
+
+	assert((size & pagesize_mask) == 0);
+	assert((alignment & pagesize_mask) == 0);
+
+#ifdef MALLOC_BALANCE
+	arena_lock_balance(arena);
+#else
+	malloc_spin_lock(&arena->lock);
+#endif
+	ret = (void *)arena_run_alloc(arena, alloc_size, true, false);
+	if (ret == NULL) {
+		malloc_spin_unlock(&arena->lock);
+		return (NULL);
+	}
+
+	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ret);
+
+	offset = (uintptr_t)ret & (alignment - 1);
+	assert((offset & pagesize_mask) == 0);
+	assert(offset < alloc_size);
+	if (offset == 0)
+		arena_run_trim_tail(arena, chunk, ret, alloc_size, size, false);
+	else {
+		size_t leadsize, trailsize;
+
+		leadsize = alignment - offset;
+		if (leadsize > 0) {
+			arena_run_trim_head(arena, chunk, ret, alloc_size,
+			    alloc_size - leadsize);
+			ret = (void *)((uintptr_t)ret + leadsize);
+		}
+
+		trailsize = alloc_size - leadsize - size;
+		if (trailsize != 0) {
+			/* Trim trailing space. */
+			assert(trailsize < alloc_size);
+			arena_run_trim_tail(arena, chunk, ret, size + trailsize,
+			    size, false);
+		}
+	}
+
+#ifdef MALLOC_STATS
+	arena->stats.nmalloc_large++;
+	arena->stats.allocated_large += size;
+#endif
+	malloc_spin_unlock(&arena->lock);
+
+	if (opt_junk)
+		memset(ret, 0xa5, size);
+	else if (opt_zero)
+		memset(ret, 0, size);
+	return (ret);
+}
+
+static inline void *
+ipalloc(size_t alignment, size_t size)
+{
+	void *ret;
+	size_t ceil_size;
+
+	/*
+	 * Round size up to the nearest multiple of alignment.
+	 *
+	 * This done, we can take advantage of the fact that for each small
+	 * size class, every object is aligned at the smallest power of two
+	 * that is non-zero in the base two representation of the size.  For
+	 * example:
+	 *
+	 *   Size |   Base 2 | Minimum alignment
+	 *   -----+----------+------------------
+	 *     96 |  1100000 |  32
+	 *    144 | 10100000 |  32
+	 *    192 | 11000000 |  64
+	 *
+	 * Depending on runtime settings, it is possible that arena_malloc()
+	 * will further round up to a power of two, but that never causes
+	 * correctness issues.
+	 */
+	ceil_size = (size + (alignment - 1)) & (-alignment);
+	/*
+	 * (ceil_size < size) protects against the combination of maximal
+	 * alignment and size greater than maximal alignment.
+	 */
+	if (ceil_size < size) {
+		/* size_t overflow. */
+		return (NULL);
+	}
+
+	if (ceil_size <= pagesize || (alignment <= pagesize
+	    && ceil_size <= arena_maxclass))
+		ret = arena_malloc(choose_arena(), ceil_size, false);
+	else {
+		size_t run_size;
+
+		/*
+		 * We can't achieve subpage alignment, so round up alignment
+		 * permanently; it makes later calculations simpler.
+		 */
+		alignment = PAGE_CEILING(alignment);
+		ceil_size = PAGE_CEILING(size);
+		/*
+		 * (ceil_size < size) protects against very large sizes within
+		 * pagesize of SIZE_T_MAX.
+		 *
+		 * (ceil_size + alignment < ceil_size) protects against the
+		 * combination of maximal alignment and ceil_size large enough
+		 * to cause overflow.  This is similar to the first overflow
+		 * check above, but it needs to be repeated due to the new
+		 * ceil_size value, which may now be *equal* to maximal
+		 * alignment, whereas before we only detected overflow if the
+		 * original size was *greater* than maximal alignment.
+		 */
+		if (ceil_size < size || ceil_size + alignment < ceil_size) {
+			/* size_t overflow. */
+			return (NULL);
+		}
+
+		/*
+		 * Calculate the size of the over-size run that arena_palloc()
+		 * would need to allocate in order to guarantee the alignment.
+		 */
+		if (ceil_size >= alignment)
+			run_size = ceil_size + alignment - pagesize;
+		else {
+			/*
+			 * It is possible that (alignment << 1) will cause
+			 * overflow, but it doesn't matter because we also
+			 * subtract pagesize, which in the case of overflow
+			 * leaves us with a very large run_size.  That causes
+			 * the first conditional below to fail, which means
+			 * that the bogus run_size value never gets used for
+			 * anything important.
+			 */
+			run_size = (alignment << 1) - pagesize;
+		}
+
+		if (run_size <= arena_maxclass) {
+			ret = arena_palloc(choose_arena(), alignment, ceil_size,
+			    run_size);
+		} else if (alignment <= chunksize)
+			ret = huge_malloc(ceil_size, false);
+		else
+			ret = huge_palloc(alignment, ceil_size);
+	}
+
+	assert(((uintptr_t)ret & (alignment - 1)) == 0);
+	return (ret);
+}
+
+/* Return the size of the allocation pointed to by ptr. */
+static size_t
+arena_salloc(const void *ptr)
+{
+	size_t ret;
+	arena_chunk_t *chunk;
+	size_t pageind, mapbits;
+
+	assert(ptr != NULL);
+	assert(CHUNK_ADDR2BASE(ptr) != ptr);
+
+	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
+	pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow);
+	mapbits = chunk->map[pageind].bits;
+	assert((mapbits & CHUNK_MAP_ALLOCATED) != 0);
+	if ((mapbits & CHUNK_MAP_LARGE) == 0) {
+		arena_run_t *run = (arena_run_t *)(mapbits & ~pagesize_mask);
+		assert(run->magic == ARENA_RUN_MAGIC);
+		ret = run->bin->reg_size;
+	} else {
+		ret = mapbits & ~pagesize_mask;
+		assert(ret != 0);
+	}
+
+	return (ret);
+}
+
+static inline size_t
+isalloc(const void *ptr)
+{
+	size_t ret;
+	arena_chunk_t *chunk;
+
+	assert(ptr != NULL);
+
+	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
+	if (chunk != ptr) {
+		/* Region. */
+		assert(chunk->arena->magic == ARENA_MAGIC);
+
+		ret = arena_salloc(ptr);
+	} else {
+		extent_node_t *node, key;
+
+		/* Chunk (huge allocation). */
+
+		malloc_mutex_lock(&huge_mtx);
+
+		/* Extract from tree of huge allocations. */
+		key.addr = __DECONST(void *, ptr);
+		node = extent_tree_ad_search(&huge, &key);
+		assert(node != NULL);
+
+		ret = node->size;
+
+		malloc_mutex_unlock(&huge_mtx);
+	}
+
+	return (ret);
+}
+
+static inline void
+arena_dalloc_small(arena_t *arena, arena_chunk_t *chunk, void *ptr,
+    arena_chunk_map_t *mapelm)
+{
+	arena_run_t *run;
+	arena_bin_t *bin;
+	size_t size;
+
+	run = (arena_run_t *)(mapelm->bits & ~pagesize_mask);
+	assert(run->magic == ARENA_RUN_MAGIC);
+	bin = run->bin;
+	size = bin->reg_size;
+
+	if (opt_junk)
+		memset(ptr, 0x5a, size);
+
+	arena_run_reg_dalloc(run, bin, ptr, size);
+	run->nfree++;
+
+	if (run->nfree == bin->nregs) {
+		/* Deallocate run. */
+		if (run == bin->runcur)
+			bin->runcur = NULL;
+		else if (bin->nregs != 1) {
+			size_t run_pageind = (((uintptr_t)run -
+			    (uintptr_t)chunk)) >> pagesize_2pow;
+			arena_chunk_map_t *run_mapelm =
+			    &chunk->map[run_pageind];
+			/*
+			 * This block's conditional is necessary because if the
+			 * run only contains one region, then it never gets
+			 * inserted into the non-full runs tree.
+			 */
+			arena_run_tree_remove(&bin->runs, run_mapelm);
+		}
+#ifdef MALLOC_DEBUG
+		run->magic = 0;
+#endif
+		arena_run_dalloc(arena, run, true);
+#ifdef MALLOC_STATS
+		bin->stats.curruns--;
+#endif
+	} else if (run->nfree == 1 && run != bin->runcur) {
+		/*
+		 * Make sure that bin->runcur always refers to the lowest
+		 * non-full run, if one exists.
+		 */
+		if (bin->runcur == NULL)
+			bin->runcur = run;
+		else if ((uintptr_t)run < (uintptr_t)bin->runcur) {
+			/* Switch runcur. */
+			if (bin->runcur->nfree > 0) {
+				arena_chunk_t *runcur_chunk =
+				    CHUNK_ADDR2BASE(bin->runcur);
+				size_t runcur_pageind =
+				    (((uintptr_t)bin->runcur -
+				    (uintptr_t)runcur_chunk)) >> pagesize_2pow;
+				arena_chunk_map_t *runcur_mapelm =
+				    &runcur_chunk->map[runcur_pageind];
+
+				/* Insert runcur. */
+				arena_run_tree_insert(&bin->runs,
+				    runcur_mapelm);
+			}
+			bin->runcur = run;
+		} else {
+			size_t run_pageind = (((uintptr_t)run -
+			    (uintptr_t)chunk)) >> pagesize_2pow;
+			arena_chunk_map_t *run_mapelm =
+			    &chunk->map[run_pageind];
+
+			assert(arena_run_tree_search(&bin->runs, run_mapelm) ==
+			    NULL);
+			arena_run_tree_insert(&bin->runs, run_mapelm);
+		}
+	}
+#ifdef MALLOC_STATS
+	arena->stats.allocated_small -= size;
+	arena->stats.ndalloc_small++;
+#endif
+}
+
+#ifdef MALLOC_MAG
+static void
+mag_unload(mag_t *mag)
+{
+	arena_chunk_t *chunk;
+	arena_t *arena;
+	void *round;
+	size_t i, ndeferred, nrounds;
+
+	for (ndeferred = mag->nrounds; ndeferred > 0;) {
+		nrounds = ndeferred;
+		/* Lock the arena associated with the first round. */
+		chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(mag->rounds[0]);
+		arena = chunk->arena;
+#ifdef MALLOC_BALANCE
+		arena_lock_balance(arena);
+#else
+		malloc_spin_lock(&arena->lock);
+#endif
+		/* Deallocate every round that belongs to the locked arena. */
+		for (i = ndeferred = 0; i < nrounds; i++) {
+			round = mag->rounds[i];
+			chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(round);
+			if (chunk->arena == arena) {
+				size_t pageind = (((uintptr_t)round -
+				    (uintptr_t)chunk) >> pagesize_2pow);
+				arena_chunk_map_t *mapelm =
+				    &chunk->map[pageind];
+				arena_dalloc_small(arena, chunk, round, mapelm);
+			} else {
+				/*
+				 * This round was allocated via a different
+				 * arena than the one that is currently locked.
+				 * Stash the round, so that it can be handled
+				 * in a future pass.
+				 */
+				mag->rounds[ndeferred] = round;
+				ndeferred++;
+			}
+		}
+		malloc_spin_unlock(&arena->lock);
+	}
+
+	mag->nrounds = 0;
+}
+
+static inline void
+mag_rack_dalloc(mag_rack_t *rack, void *ptr)
+{
+	arena_t *arena;
+	arena_chunk_t *chunk;
+	arena_run_t *run;
+	arena_bin_t *bin;
+	bin_mags_t *bin_mags;
+	mag_t *mag;
+	size_t pageind, binind;
+	arena_chunk_map_t *mapelm;
+
+	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
+	arena = chunk->arena;
+	pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow);
+	mapelm = &chunk->map[pageind];
+	run = (arena_run_t *)(mapelm->bits & ~pagesize_mask);
+	assert(run->magic == ARENA_RUN_MAGIC);
+	bin = run->bin;
+	binind = ((uintptr_t)bin - (uintptr_t)&arena->bins) /
+	    sizeof(arena_bin_t);
+	assert(binind < nbins);
+
+	if (opt_junk)
+		memset(ptr, 0x5a, arena->bins[binind].reg_size);
+
+	bin_mags = &rack->bin_mags[binind];
+	mag = bin_mags->curmag;
+	if (mag == NULL) {
+		/* Create an initial magazine for this size class. */
+		assert(bin_mags->sparemag == NULL);
+		mag = mag_create(choose_arena(), binind);
+		if (mag == NULL) {
+			malloc_spin_lock(&arena->lock);
+			arena_dalloc_small(arena, chunk, ptr, mapelm);
+			malloc_spin_unlock(&arena->lock);
+			return;
+		}
+		bin_mags->curmag = mag;
+	}
+
+	if (mag->nrounds == max_rounds) {
+		if (bin_mags->sparemag != NULL) {
+			if (bin_mags->sparemag->nrounds < max_rounds) {
+				/* Swap magazines. */
+				bin_mags->curmag = bin_mags->sparemag;
+				bin_mags->sparemag = mag;
+				mag = bin_mags->curmag;
+			} else {
+				/* Unload the current magazine. */
+				mag_unload(mag);
+			}
+		} else {
+			/* Create a second magazine. */
+			mag = mag_create(choose_arena(), binind);
+			if (mag == NULL) {
+				mag = rack->bin_mags[binind].curmag;
+				mag_unload(mag);
+			} else {
+				bin_mags->sparemag = bin_mags->curmag;
+				bin_mags->curmag = mag;
+			}
+		}
+		assert(mag->nrounds < max_rounds);
+	}
+	mag->rounds[mag->nrounds] = ptr;
+	mag->nrounds++;
+}
+#endif
+
+static void
+arena_dalloc_large(arena_t *arena, arena_chunk_t *chunk, void *ptr)
+{
+	/* Large allocation. */
+	malloc_spin_lock(&arena->lock);
+
+#ifndef MALLOC_STATS
+	if (opt_junk)
+#endif
+	{
+		size_t pageind = ((uintptr_t)ptr - (uintptr_t)chunk) >>
+		    pagesize_2pow;
+		size_t size = chunk->map[pageind].bits & ~pagesize_mask;
+
+#ifdef MALLOC_STATS
+		if (opt_junk)
+#endif
+			memset(ptr, 0x5a, size);
+#ifdef MALLOC_STATS
+		arena->stats.allocated_large -= size;
+#endif
+	}
+#ifdef MALLOC_STATS
+	arena->stats.ndalloc_large++;
+#endif
+
+	arena_run_dalloc(arena, (arena_run_t *)ptr, true);
+	malloc_spin_unlock(&arena->lock);
+}
+
+static inline void
+arena_dalloc(arena_t *arena, arena_chunk_t *chunk, void *ptr)
+{
+	size_t pageind;
+	arena_chunk_map_t *mapelm;
+
+	assert(arena != NULL);
+	assert(arena->magic == ARENA_MAGIC);
+	assert(chunk->arena == arena);
+	assert(ptr != NULL);
+	assert(CHUNK_ADDR2BASE(ptr) != ptr);
+
+	pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow);
+	mapelm = &chunk->map[pageind];
+	assert((mapelm->bits & CHUNK_MAP_ALLOCATED) != 0);
+	if ((mapelm->bits & CHUNK_MAP_LARGE) == 0) {
+		/* Small allocation. */
+#ifdef MALLOC_MAG
+		if (__isthreaded && opt_mag) {
+			mag_rack_t *rack = mag_rack;
+			if (rack == NULL) {
+				rack = mag_rack_create(arena);
+				if (rack == NULL) {
+					malloc_spin_lock(&arena->lock);
+					arena_dalloc_small(arena, chunk, ptr,
+					    mapelm);
+					malloc_spin_unlock(&arena->lock);
+				}
+				mag_rack = rack;
+			}
+			mag_rack_dalloc(rack, ptr);
+		} else {
+#endif
+			malloc_spin_lock(&arena->lock);
+			arena_dalloc_small(arena, chunk, ptr, mapelm);
+			malloc_spin_unlock(&arena->lock);
+#ifdef MALLOC_MAG
+		}
+#endif
+	} else
+		arena_dalloc_large(arena, chunk, ptr);
+}
+
+static inline void
+idalloc(void *ptr)
+{
+	arena_chunk_t *chunk;
+
+	assert(ptr != NULL);
+
+	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
+	if (chunk != ptr)
+		arena_dalloc(chunk->arena, chunk, ptr);
+	else
+		huge_dalloc(ptr);
+}
+
+static void
+arena_ralloc_large_shrink(arena_t *arena, arena_chunk_t *chunk, void *ptr,
+    size_t size, size_t oldsize)
+{
+
+	assert(size < oldsize);
+
+	/*
+	 * Shrink the run, and make trailing pages available for other
+	 * allocations.
+	 */
+#ifdef MALLOC_BALANCE
+	arena_lock_balance(arena);
+#else
+	malloc_spin_lock(&arena->lock);
+#endif
+	arena_run_trim_tail(arena, chunk, (arena_run_t *)ptr, oldsize, size,
+	    true);
+#ifdef MALLOC_STATS
+	arena->stats.allocated_large -= oldsize - size;
+#endif
+	malloc_spin_unlock(&arena->lock);
+}
+
+static bool
+arena_ralloc_large_grow(arena_t *arena, arena_chunk_t *chunk, void *ptr,
+    size_t size, size_t oldsize)
+{
+	size_t pageind = ((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow;
+	size_t npages = oldsize >> pagesize_2pow;
+
+	assert(oldsize == (chunk->map[pageind].bits & ~pagesize_mask));
+
+	/* Try to extend the run. */
+	assert(size > oldsize);
+#ifdef MALLOC_BALANCE
+	arena_lock_balance(arena);
+#else
+	malloc_spin_lock(&arena->lock);
+#endif
+	if (pageind + npages < chunk_npages && (chunk->map[pageind+npages].bits
+	    & CHUNK_MAP_ALLOCATED) == 0 && (chunk->map[pageind+npages].bits &
+	    ~pagesize_mask) >= size - oldsize) {
+		/*
+		 * The next run is available and sufficiently large.  Split the
+		 * following run, then merge the first part with the existing
+		 * allocation.
+		 */
+		arena_run_split(arena, (arena_run_t *)((uintptr_t)chunk +
+		    ((pageind+npages) << pagesize_2pow)), size - oldsize, true,
+		    false);
+
+		chunk->map[pageind].bits = size | CHUNK_MAP_LARGE |
+		    CHUNK_MAP_ALLOCATED;
+		chunk->map[pageind+npages].bits = CHUNK_MAP_LARGE |
+		    CHUNK_MAP_ALLOCATED;
+
+#ifdef MALLOC_STATS
+		arena->stats.allocated_large += size - oldsize;
+#endif
+		malloc_spin_unlock(&arena->lock);
+		return (false);
+	}
+	malloc_spin_unlock(&arena->lock);
+
+	return (true);
+}
+
+/*
+ * Try to resize a large allocation, in order to avoid copying.  This will
+ * always fail if growing an object, and the following run is already in use.
+ */
+static bool
+arena_ralloc_large(void *ptr, size_t size, size_t oldsize)
+{
+	size_t psize;
+
+	psize = PAGE_CEILING(size);
+	if (psize == oldsize) {
+		/* Same size class. */
+		if (opt_junk && size < oldsize) {
+			memset((void *)((uintptr_t)ptr + size), 0x5a, oldsize -
+			    size);
+		}
+		return (false);
+	} else {
+		arena_chunk_t *chunk;
+		arena_t *arena;
+
+		chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
+		arena = chunk->arena;
+		assert(arena->magic == ARENA_MAGIC);
+
+		if (psize < oldsize) {
+			/* Fill before shrinking in order avoid a race. */
+			if (opt_junk) {
+				memset((void *)((uintptr_t)ptr + size), 0x5a,
+				    oldsize - size);
+			}
+			arena_ralloc_large_shrink(arena, chunk, ptr, psize,
+			    oldsize);
+			return (false);
+		} else {
+			bool ret = arena_ralloc_large_grow(arena, chunk, ptr,
+			    psize, oldsize);
+			if (ret == false && opt_zero) {
+				memset((void *)((uintptr_t)ptr + oldsize), 0,
+				    size - oldsize);
+			}
+			return (ret);
+		}
+	}
+}
+
+static void *
+arena_ralloc(void *ptr, size_t size, size_t oldsize)
+{
+	void *ret;
+	size_t copysize;
+
+	/* Try to avoid moving the allocation. */
+	if (size <= bin_maxclass) {
+		if (oldsize <= bin_maxclass && size2bin[size] ==
+		    size2bin[oldsize])
+			goto IN_PLACE;
+	} else {
+		if (oldsize > bin_maxclass && oldsize <= arena_maxclass) {
+			assert(size > bin_maxclass);
+			if (arena_ralloc_large(ptr, size, oldsize) == false)
+				return (ptr);
+		}
+	}
+
+	/*
+	 * If we get here, then size and oldsize are different enough that we
+	 * need to move the object.  In that case, fall back to allocating new
+	 * space and copying.
+	 */
+	ret = arena_malloc(choose_arena(), size, false);
+	if (ret == NULL)
+		return (NULL);
+
+	/* Junk/zero-filling were already done by arena_malloc(). */
+	copysize = (size < oldsize) ? size : oldsize;
+	memcpy(ret, ptr, copysize);
+	idalloc(ptr);
+	return (ret);
+IN_PLACE:
+	if (opt_junk && size < oldsize)
+		memset((void *)((uintptr_t)ptr + size), 0x5a, oldsize - size);
+	else if (opt_zero && size > oldsize)
+		memset((void *)((uintptr_t)ptr + oldsize), 0, size - oldsize);
+	return (ptr);
+}
+
+static inline void *
+iralloc(void *ptr, size_t size)
+{
+	size_t oldsize;
+
+	assert(ptr != NULL);
+	assert(size != 0);
+
+	oldsize = isalloc(ptr);
+
+	if (size <= arena_maxclass)
+		return (arena_ralloc(ptr, size, oldsize));
+	else
+		return (huge_ralloc(ptr, size, oldsize));
+}
+
+static bool
+arena_new(arena_t *arena)
+{
+	unsigned i;
+	arena_bin_t *bin;
+	size_t prev_run_size;
+
+	if (malloc_spin_init(&arena->lock))
+		return (true);
+
+#ifdef MALLOC_STATS
+	memset(&arena->stats, 0, sizeof(arena_stats_t));
+#endif
+
+	/* Initialize chunks. */
+	arena_chunk_tree_dirty_new(&arena->chunks_dirty);
+	arena->spare = NULL;
+
+	arena->ndirty = 0;
+
+	arena_avail_tree_new(&arena->runs_avail);
+
+#ifdef MALLOC_BALANCE
+	arena->contention = 0;
+#endif
+
+	/* Initialize bins. */
+	prev_run_size = pagesize;
+
+	i = 0;
+#ifdef MALLOC_TINY
+	/* (2^n)-spaced tiny bins. */
+	for (; i < ntbins; i++) {
+		bin = &arena->bins[i];
+		bin->runcur = NULL;
+		arena_run_tree_new(&bin->runs);
+
+		bin->reg_size = (1U << (TINY_MIN_2POW + i));
+
+		prev_run_size = arena_bin_run_size_calc(bin, prev_run_size);
+
+#ifdef MALLOC_STATS
+		memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
+#endif
+	}
+#endif
+
+	/* Quantum-spaced bins. */
+	for (; i < ntbins + nqbins; i++) {
+		bin = &arena->bins[i];
+		bin->runcur = NULL;
+		arena_run_tree_new(&bin->runs);
+
+		bin->reg_size = (i - ntbins + 1) << QUANTUM_2POW;
+
+		prev_run_size = arena_bin_run_size_calc(bin, prev_run_size);
+
+#ifdef MALLOC_STATS
+		memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
+#endif
+	}
+
+	/* Cacheline-spaced bins. */
+	for (; i < ntbins + nqbins + ncbins; i++) {
+		bin = &arena->bins[i];
+		bin->runcur = NULL;
+		arena_run_tree_new(&bin->runs);
+
+		bin->reg_size = cspace_min + ((i - (ntbins + nqbins)) <<
+		    CACHELINE_2POW);
+
+		prev_run_size = arena_bin_run_size_calc(bin, prev_run_size);
+
+#ifdef MALLOC_STATS
+		memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
+#endif
+	}
+
+	/* Subpage-spaced bins. */
+	for (; i < nbins; i++) {
+		bin = &arena->bins[i];
+		bin->runcur = NULL;
+		arena_run_tree_new(&bin->runs);
+
+		bin->reg_size = sspace_min + ((i - (ntbins + nqbins + ncbins))
+		    << SUBPAGE_2POW);
+
+		prev_run_size = arena_bin_run_size_calc(bin, prev_run_size);
+
+#ifdef MALLOC_STATS
+		memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
+#endif
+	}
+
+#ifdef MALLOC_DEBUG
+	arena->magic = ARENA_MAGIC;
+#endif
+
+	return (false);
+}
+
+/* Create a new arena and insert it into the arenas array at index ind. */
+static arena_t *
+arenas_extend(unsigned ind)
+{
+	arena_t *ret;
+
+	/* Allocate enough space for trailing bins. */
+	ret = (arena_t *)base_alloc(sizeof(arena_t)
+	    + (sizeof(arena_bin_t) * (nbins - 1)));
+	if (ret != NULL && arena_new(ret) == false) {
+		arenas[ind] = ret;
+		return (ret);
+	}
+	/* Only reached if there is an OOM error. */
+
+	/*
+	 * OOM here is quite inconvenient to propagate, since dealing with it
+	 * would require a check for failure in the fast path.  Instead, punt
+	 * by using arenas[0].  In practice, this is an extremely unlikely
+	 * failure.
+	 */
+	_malloc_message(_getprogname(),
+	    ": (malloc) Error initializing arena\n", "", "");
+	if (opt_abort)
+		abort();
+
+	return (arenas[0]);
+}
+
+#ifdef MALLOC_MAG
+static mag_t *
+mag_create(arena_t *arena, size_t binind)
+{
+	mag_t *ret;
+
+	if (sizeof(mag_t) + (sizeof(void *) * (max_rounds - 1)) <=
+	    bin_maxclass) {
+		ret = arena_malloc_small(arena, sizeof(mag_t) + (sizeof(void *)
+		    * (max_rounds - 1)), false);
+	} else {
+		ret = imalloc(sizeof(mag_t) + (sizeof(void *) * (max_rounds -
+		    1)));
+	}
+	if (ret == NULL)
+		return (NULL);
+	ret->binind = binind;
+	ret->nrounds = 0;
+
+	return (ret);
+}
+
+static void
+mag_destroy(mag_t *mag)
+{
+	arena_t *arena;
+	arena_chunk_t *chunk;
+	size_t pageind;
+	arena_chunk_map_t *mapelm;
+
+	chunk = CHUNK_ADDR2BASE(mag);
+	arena = chunk->arena;
+	pageind = (((uintptr_t)mag - (uintptr_t)chunk) >> pagesize_2pow);
+	mapelm = &chunk->map[pageind];
+
+	assert(mag->nrounds == 0);
+	if (sizeof(mag_t) + (sizeof(void *) * (max_rounds - 1)) <=
+	    bin_maxclass) {
+		malloc_spin_lock(&arena->lock);
+		arena_dalloc_small(arena, chunk, mag, mapelm);
+		malloc_spin_unlock(&arena->lock);
+	} else
+		idalloc(mag);
+}
+
+static mag_rack_t *
+mag_rack_create(arena_t *arena)
+{
+
+	assert(sizeof(mag_rack_t) + (sizeof(bin_mags_t *) * (nbins - 1)) <=
+	    bin_maxclass);
+	return (arena_malloc_small(arena, sizeof(mag_rack_t) +
+	    (sizeof(bin_mags_t) * (nbins - 1)), true));
+}
+
+static void
+mag_rack_destroy(mag_rack_t *rack)
+{
+	arena_t *arena;
+	arena_chunk_t *chunk;
+	bin_mags_t *bin_mags;
+	size_t i, pageind;
+	arena_chunk_map_t *mapelm;
+
+	for (i = 0; i < nbins; i++) {
+		bin_mags = &rack->bin_mags[i];
+		if (bin_mags->curmag != NULL) {
+			assert(bin_mags->curmag->binind == i);
+			mag_unload(bin_mags->curmag);
+			mag_destroy(bin_mags->curmag);
+		}
+		if (bin_mags->sparemag != NULL) {
+			assert(bin_mags->sparemag->binind == i);
+			mag_unload(bin_mags->sparemag);
+			mag_destroy(bin_mags->sparemag);
+		}
+	}
+
+	chunk = CHUNK_ADDR2BASE(rack);
+	arena = chunk->arena;
+	pageind = (((uintptr_t)rack - (uintptr_t)chunk) >> pagesize_2pow);
+	mapelm = &chunk->map[pageind];
+
+	malloc_spin_lock(&arena->lock);
+	arena_dalloc_small(arena, chunk, rack, mapelm);
+	malloc_spin_unlock(&arena->lock);
+}
+#endif
+
+/*
+ * End arena.
+ */
+/******************************************************************************/
+/*
+ * Begin general internal functions.
+ */
+
+static void *
+huge_malloc(size_t size, bool zero)
+{
+	void *ret;
+	size_t csize;
+	extent_node_t *node;
+
+	/* Allocate one or more contiguous chunks for this request. */
+
+	csize = CHUNK_CEILING(size);
+	if (csize == 0) {
+		/* size is large enough to cause size_t wrap-around. */
+		return (NULL);
+	}
+
+	/* Allocate an extent node with which to track the chunk. */
+	node = base_node_alloc();
+	if (node == NULL)
+		return (NULL);
+
+	ret = chunk_alloc(csize, zero);
+	if (ret == NULL) {
+		base_node_dealloc(node);
+		return (NULL);
+	}
+
+	/* Insert node into huge. */
+	node->addr = ret;
+	node->size = csize;
+
+	malloc_mutex_lock(&huge_mtx);
+	extent_tree_ad_insert(&huge, node);
+#ifdef MALLOC_STATS
+	huge_nmalloc++;
+	huge_allocated += csize;
+#endif
+	malloc_mutex_unlock(&huge_mtx);
+
+	if (zero == false) {
+		if (opt_junk)
+			memset(ret, 0xa5, csize);
+		else if (opt_zero)
+			memset(ret, 0, csize);
+	}
+
+	return (ret);
+}
+
+/* Only handles large allocations that require more than chunk alignment. */
+static void *
+huge_palloc(size_t alignment, size_t size)
+{
+	void *ret;
+	size_t alloc_size, chunk_size, offset;
+	extent_node_t *node;
+
+	/*
+	 * This allocation requires alignment that is even larger than chunk
+	 * alignment.  This means that huge_malloc() isn't good enough.
+	 *
+	 * Allocate almost twice as many chunks as are demanded by the size or
+	 * alignment, in order to assure the alignment can be achieved, then
+	 * unmap leading and trailing chunks.
+	 */
+	assert(alignment >= chunksize);
+
+	chunk_size = CHUNK_CEILING(size);
+
+	if (size >= alignment)
+		alloc_size = chunk_size + alignment - chunksize;
+	else
+		alloc_size = (alignment << 1) - chunksize;
+
+	/* Allocate an extent node with which to track the chunk. */
+	node = base_node_alloc();
+	if (node == NULL)
+		return (NULL);
+
+	ret = chunk_alloc(alloc_size, false);
+	if (ret == NULL) {
+		base_node_dealloc(node);
+		return (NULL);
+	}
+
+	offset = (uintptr_t)ret & (alignment - 1);
+	assert((offset & chunksize_mask) == 0);
+	assert(offset < alloc_size);
+	if (offset == 0) {
+		/* Trim trailing space. */
+		chunk_dealloc((void *)((uintptr_t)ret + chunk_size), alloc_size
+		    - chunk_size);
+	} else {
+		size_t trailsize;
+
+		/* Trim leading space. */
+		chunk_dealloc(ret, alignment - offset);
+
+		ret = (void *)((uintptr_t)ret + (alignment - offset));
+
+		trailsize = alloc_size - (alignment - offset) - chunk_size;
+		if (trailsize != 0) {
+		    /* Trim trailing space. */
+		    assert(trailsize < alloc_size);
+		    chunk_dealloc((void *)((uintptr_t)ret + chunk_size),
+			trailsize);
+		}
+	}
+
+	/* Insert node into huge. */
+	node->addr = ret;
+	node->size = chunk_size;
+
+	malloc_mutex_lock(&huge_mtx);
+	extent_tree_ad_insert(&huge, node);
+#ifdef MALLOC_STATS
+	huge_nmalloc++;
+	huge_allocated += chunk_size;
+#endif
+	malloc_mutex_unlock(&huge_mtx);
+
+	if (opt_junk)
+		memset(ret, 0xa5, chunk_size);
+	else if (opt_zero)
+		memset(ret, 0, chunk_size);
+
+	return (ret);
+}
+
+static void *
+huge_ralloc(void *ptr, size_t size, size_t oldsize)
+{
+	void *ret;
+	size_t copysize;
+
+	/* Avoid moving the allocation if the size class would not change. */
+	if (oldsize > arena_maxclass &&
+	    CHUNK_CEILING(size) == CHUNK_CEILING(oldsize)) {
+		if (opt_junk && size < oldsize) {
+			memset((void *)((uintptr_t)ptr + size), 0x5a, oldsize
+			    - size);
+		} else if (opt_zero && size > oldsize) {
+			memset((void *)((uintptr_t)ptr + oldsize), 0, size
+			    - oldsize);
+		}
+		return (ptr);
+	}
+
+	/*
+	 * If we get here, then size and oldsize are different enough that we
+	 * need to use a different size class.  In that case, fall back to
+	 * allocating new space and copying.
+	 */
+	ret = huge_malloc(size, false);
+	if (ret == NULL)
+		return (NULL);
+
+	copysize = (size < oldsize) ? size : oldsize;
+	memcpy(ret, ptr, copysize);
+	idalloc(ptr);
+	return (ret);
+}
+
+static void
+huge_dalloc(void *ptr)
+{
+	extent_node_t *node, key;
+
+	malloc_mutex_lock(&huge_mtx);
+
+	/* Extract from tree of huge allocations. */
+	key.addr = ptr;
+	node = extent_tree_ad_search(&huge, &key);
+	assert(node != NULL);
+	assert(node->addr == ptr);
+	extent_tree_ad_remove(&huge, node);
+
+#ifdef MALLOC_STATS
+	huge_ndalloc++;
+	huge_allocated -= node->size;
+#endif
+
+	malloc_mutex_unlock(&huge_mtx);
+
+	/* Unmap chunk. */
+#ifdef MALLOC_DSS
+	if (opt_dss && opt_junk)
+		memset(node->addr, 0x5a, node->size);
+#endif
+	chunk_dealloc(node->addr, node->size);
+
+	base_node_dealloc(node);
+}
+
+static void
+malloc_print_stats(void)
+{
+
+	if (opt_print_stats) {
+		char s[UMAX2S_BUFSIZE];
+		_malloc_message("___ Begin malloc statistics ___\n", "", "",
+		    "");
+		_malloc_message("Assertions ",
+#ifdef NDEBUG
+		    "disabled",
+#else
+		    "enabled",
+#endif
+		    "\n", "");
+		_malloc_message("Boolean MALLOC_OPTIONS: ",
+		    opt_abort ? "A" : "a", "", "");
+#ifdef MALLOC_DSS
+		_malloc_message(opt_dss ? "D" : "d", "", "", "");
+#endif
+#ifdef MALLOC_MAG
+		_malloc_message(opt_mag ? "G" : "g", "", "", "");
+#endif
+		_malloc_message(opt_junk ? "J" : "j", "", "", "");
+#ifdef MALLOC_DSS
+		_malloc_message(opt_mmap ? "M" : "m", "", "", "");
+#endif
+		_malloc_message(opt_utrace ? "PU" : "Pu",
+		    opt_sysv ? "V" : "v",
+		    opt_xmalloc ? "X" : "x",
+		    opt_zero ? "Z\n" : "z\n");
+
+		_malloc_message("CPUs: ", umax2s(ncpus, s), "\n", "");
+		_malloc_message("Max arenas: ", umax2s(narenas, s), "\n", "");
+#ifdef MALLOC_BALANCE
+		_malloc_message("Arena balance threshold: ",
+		    umax2s(opt_balance_threshold, s), "\n", "");
+#endif
+		_malloc_message("Pointer size: ", umax2s(sizeof(void *), s),
+		    "\n", "");
+		_malloc_message("Quantum size: ", umax2s(QUANTUM, s), "\n", "");
+		_malloc_message("Cacheline size (assumed): ", umax2s(CACHELINE,
+		    s), "\n", "");
+#ifdef MALLOC_TINY
+		_malloc_message("Tiny 2^n-spaced sizes: [", umax2s((1U <<
+		    TINY_MIN_2POW), s), "..", "");
+		_malloc_message(umax2s((qspace_min >> 1), s), "]\n", "", "");
+#endif
+		_malloc_message("Quantum-spaced sizes: [", umax2s(qspace_min,
+		    s), "..", "");
+		_malloc_message(umax2s(qspace_max, s), "]\n", "", "");
+		_malloc_message("Cacheline-spaced sizes: [", umax2s(cspace_min,
+		    s), "..", "");
+		_malloc_message(umax2s(cspace_max, s), "]\n", "", "");
+		_malloc_message("Subpage-spaced sizes: [", umax2s(sspace_min,
+		    s), "..", "");
+		_malloc_message(umax2s(sspace_max, s), "]\n", "", "");
+#ifdef MALLOC_MAG
+		_malloc_message("Rounds per magazine: ", umax2s(max_rounds, s),
+		    "\n", "");
+#endif
+		_malloc_message("Max dirty pages per arena: ",
+		    umax2s(opt_dirty_max, s), "\n", "");
+
+		_malloc_message("Chunk size: ", umax2s(chunksize, s), "", "");
+		_malloc_message(" (2^", umax2s(opt_chunk_2pow, s), ")\n", "");
+
+#ifdef MALLOC_STATS
+		{
+			size_t allocated, mapped;
+#ifdef MALLOC_BALANCE
+			uint64_t nbalance = 0;
+#endif
+			unsigned i;
+			arena_t *arena;
+
+			/* Calculate and print allocated/mapped stats. */
+
+			/* arenas. */
+			for (i = 0, allocated = 0; i < narenas; i++) {
+				if (arenas[i] != NULL) {
+					malloc_spin_lock(&arenas[i]->lock);
+					allocated +=
+					    arenas[i]->stats.allocated_small;
+					allocated +=
+					    arenas[i]->stats.allocated_large;
+#ifdef MALLOC_BALANCE
+					nbalance += arenas[i]->stats.nbalance;
+#endif
+					malloc_spin_unlock(&arenas[i]->lock);
+				}
+			}
+
+			/* huge/base. */
+			malloc_mutex_lock(&huge_mtx);
+			allocated += huge_allocated;
+			mapped = stats_chunks.curchunks * chunksize;
+			malloc_mutex_unlock(&huge_mtx);
+
+			malloc_mutex_lock(&base_mtx);
+			mapped += base_mapped;
+			malloc_mutex_unlock(&base_mtx);
+
+			malloc_printf("Allocated: %zu, mapped: %zu\n",
+			    allocated, mapped);
+
+#ifdef MALLOC_BALANCE
+			malloc_printf("Arena balance reassignments: %llu\n",
+			    nbalance);
+#endif
+
+			/* Print chunk stats. */
+			{
+				chunk_stats_t chunks_stats;
+
+				malloc_mutex_lock(&huge_mtx);
+				chunks_stats = stats_chunks;
+				malloc_mutex_unlock(&huge_mtx);
+
+				malloc_printf("chunks: nchunks   "
+				    "highchunks    curchunks\n");
+				malloc_printf("  %13llu%13lu%13lu\n",
+				    chunks_stats.nchunks,
+				    chunks_stats.highchunks,
+				    chunks_stats.curchunks);
+			}
+
+			/* Print chunk stats. */
+			malloc_printf(
+			    "huge: nmalloc      ndalloc    allocated\n");
+			malloc_printf(" %12llu %12llu %12zu\n",
+			    huge_nmalloc, huge_ndalloc, huge_allocated);
+
+			/* Print stats for each arena. */
+			for (i = 0; i < narenas; i++) {
+				arena = arenas[i];
+				if (arena != NULL) {
+					malloc_printf(
+					    "\narenas[%u]:\n", i);
+					malloc_spin_lock(&arena->lock);
+					stats_print(arena);
+					malloc_spin_unlock(&arena->lock);
+				}
+			}
+		}
+#endif /* #ifdef MALLOC_STATS */
+		_malloc_message("--- End malloc statistics ---\n", "", "", "");
+	}
+}
+
+#ifdef MALLOC_DEBUG
+static void
+size2bin_validate(void)
+{
+	size_t i, size, binind;
+
+	assert(size2bin[0] == 0xffU);
+	i = 1;
+#  ifdef MALLOC_TINY
+	/* Tiny. */
+	for (; i < (1U << TINY_MIN_2POW); i++) {
+		size = pow2_ceil(1U << TINY_MIN_2POW);
+		binind = ffs((int)(size >> (TINY_MIN_2POW + 1)));
+		assert(size2bin[i] == binind);
+	}
+	for (; i < qspace_min; i++) {
+		size = pow2_ceil(i);
+		binind = ffs((int)(size >> (TINY_MIN_2POW + 1)));
+		assert(size2bin[i] == binind);
+	}
+#  endif
+	/* Quantum-spaced. */
+	for (; i <= qspace_max; i++) {
+		size = QUANTUM_CEILING(i);
+		binind = ntbins + (size >> QUANTUM_2POW) - 1;
+		assert(size2bin[i] == binind);
+	}
+	/* Cacheline-spaced. */
+	for (; i <= cspace_max; i++) {
+		size = CACHELINE_CEILING(i);
+		binind = ntbins + nqbins + ((size - cspace_min) >>
+		    CACHELINE_2POW);
+		assert(size2bin[i] == binind);
+	}
+	/* Sub-page. */
+	for (; i <= sspace_max; i++) {
+		size = SUBPAGE_CEILING(i);
+		binind = ntbins + nqbins + ncbins + ((size - sspace_min)
+		    >> SUBPAGE_2POW);
+		assert(size2bin[i] == binind);
+	}
+}
+#endif
+
+static bool
+size2bin_init(void)
+{
+
+	if (opt_qspace_max_2pow != QSPACE_MAX_2POW_DEFAULT
+	    || opt_cspace_max_2pow != CSPACE_MAX_2POW_DEFAULT)
+		return (size2bin_init_hard());
+
+	size2bin = const_size2bin;
+#ifdef MALLOC_DEBUG
+	assert(sizeof(const_size2bin) == bin_maxclass + 1);
+	size2bin_validate();
+#endif
+	return (false);
+}
+
+static bool
+size2bin_init_hard(void)
+{
+	size_t i, size, binind;
+	uint8_t *custom_size2bin;
+
+	assert(opt_qspace_max_2pow != QSPACE_MAX_2POW_DEFAULT
+	    || opt_cspace_max_2pow != CSPACE_MAX_2POW_DEFAULT);
+
+	custom_size2bin = (uint8_t *)base_alloc(bin_maxclass + 1);
+	if (custom_size2bin == NULL)
+		return (true);
+
+	custom_size2bin[0] = 0xffU;
+	i = 1;
+#ifdef MALLOC_TINY
+	/* Tiny. */
+	for (; i < (1U << TINY_MIN_2POW); i++) {
+		size = pow2_ceil(1U << TINY_MIN_2POW);
+		binind = ffs((int)(size >> (TINY_MIN_2POW + 1)));
+		custom_size2bin[i] = binind;
+	}
+	for (; i < qspace_min; i++) {
+		size = pow2_ceil(i);
+		binind = ffs((int)(size >> (TINY_MIN_2POW + 1)));
+		custom_size2bin[i] = binind;
+	}
+#endif
+	/* Quantum-spaced. */
+	for (; i <= qspace_max; i++) {
+		size = QUANTUM_CEILING(i);
+		binind = ntbins + (size >> QUANTUM_2POW) - 1;
+		custom_size2bin[i] = binind;
+	}
+	/* Cacheline-spaced. */
+	for (; i <= cspace_max; i++) {
+		size = CACHELINE_CEILING(i);
+		binind = ntbins + nqbins + ((size - cspace_min) >>
+		    CACHELINE_2POW);
+		custom_size2bin[i] = binind;
+	}
+	/* Sub-page. */
+	for (; i <= sspace_max; i++) {
+		size = SUBPAGE_CEILING(i);
+		binind = ntbins + nqbins + ncbins + ((size - sspace_min) >>
+		    SUBPAGE_2POW);
+		custom_size2bin[i] = binind;
+	}
+
+	size2bin = custom_size2bin;
+#ifdef MALLOC_DEBUG
+	size2bin_validate();
+#endif
+	return (false);
+}
+
+static unsigned
+malloc_ncpus(void)
+{
+	unsigned ret;
+	int fd, nread, column;
+	char buf[1];
+	static const char matchstr[] = "processor\t:";
+
+	/*
+	 * sysconf(3) would be the preferred method for determining the number
+	 * of CPUs, but it uses malloc internally, which causes untennable
+	 * recursion during malloc initialization.
+	 */
+	fd = open("/proc/cpuinfo", O_RDONLY);
+	if (fd == -1)
+		return (1); /* Error. */
+	/*
+	 * Count the number of occurrences of matchstr at the beginnings of
+	 * lines.  This treats hyperthreaded CPUs as multiple processors.
+	 */
+	column = 0;
+	ret = 0;
+	while (true) {
+		nread = read(fd, &buf, sizeof(buf));
+		if (nread <= 0)
+			break; /* EOF or error. */
+
+		if (buf[0] == '\n')
+			column = 0;
+		else if (column != -1) {
+			if (buf[0] == matchstr[column]) {
+				column++;
+				if (column == sizeof(matchstr) - 1) {
+					column = -1;
+					ret++;
+				}
+			} else
+				column = -1;
+		}
+	}
+	if (ret == 0)
+		ret = 1; /* Something went wrong in the parser. */
+	close(fd);
+
+	return (ret);
+}
+/*
+ * FreeBSD's pthreads implementation calls malloc(3), so the malloc
+ * implementation has to take pains to avoid infinite recursion during
+ * initialization.
+ */
+static inline bool
+malloc_init(void)
+{
+
+	if (malloc_initialized == false)
+		return (malloc_init_hard());
+
+	return (false);
+}
+
+static bool
+malloc_init_hard(void)
+{
+	unsigned i;
+	int linklen;
+	char buf[PATH_MAX + 1];
+	const char *opts;
+
+	malloc_mutex_lock(&init_lock);
+	if (malloc_initialized) {
+		/*
+		 * Another thread initialized the allocator before this one
+		 * acquired init_lock.
+		 */
+		malloc_mutex_unlock(&init_lock);
+		return (false);
+	}
+
+	/* Get number of CPUs. */
+	ncpus = malloc_ncpus();
+
+	/* Get page size. */
+	{
+		long result;
+
+		result = sysconf(_SC_PAGESIZE);
+		assert(result != -1);
+		pagesize = (unsigned)result;
+
+		/*
+		 * We assume that pagesize is a power of 2 when calculating
+		 * pagesize_mask and pagesize_2pow.
+		 */
+		assert(((result - 1) & result) == 0);
+		pagesize_mask = result - 1;
+		pagesize_2pow = ffs((int)result) - 1;
+	}
+
+	for (i = 0; i < 3; i++) {
+		unsigned j;
+
+		/* Get runtime configuration. */
+		switch (i) {
+		case 0:
+			if ((linklen = readlink("/etc/malloc.conf", buf,
+						sizeof(buf) - 1)) != -1) {
+				/*
+				 * Use the contents of the "/etc/malloc.conf"
+				 * symbolic link's name.
+				 */
+				buf[linklen] = '\0';
+				opts = buf;
+			} else {
+				/* No configuration specified. */
+				buf[0] = '\0';
+				opts = buf;
+			}
+			break;
+		case 1:
+			if (issetugid() == 0 && (opts =
+			    getenv("MALLOC_OPTIONS")) != NULL) {
+				/*
+				 * Do nothing; opts is already initialized to
+				 * the value of the MALLOC_OPTIONS environment
+				 * variable.
+				 */
+			} else {
+				/* No configuration specified. */
+				buf[0] = '\0';
+				opts = buf;
+			}
+			break;
+		case 2:
+			if (_malloc_options != NULL) {
+				/*
+				 * Use options that were compiled into the
+				 * program.
+				 */
+				opts = _malloc_options;
+			} else {
+				/* No configuration specified. */
+				buf[0] = '\0';
+				opts = buf;
+			}
+			break;
+		default:
+			/* NOTREACHED */
+			assert(false);
+		}
+
+		for (j = 0; opts[j] != '\0'; j++) {
+			unsigned k, nreps;
+			bool nseen;
+
+			/* Parse repetition count, if any. */
+			for (nreps = 0, nseen = false;; j++, nseen = true) {
+				switch (opts[j]) {
+					case '0': case '1': case '2': case '3':
+					case '4': case '5': case '6': case '7':
+					case '8': case '9':
+						nreps *= 10;
+						nreps += opts[j] - '0';
+						break;
+					default:
+						goto MALLOC_OUT;
+				}
+			}
+MALLOC_OUT:
+			if (nseen == false)
+				nreps = 1;
+
+			for (k = 0; k < nreps; k++) {
+				switch (opts[j]) {
+				case 'a':
+					opt_abort = false;
+					break;
+				case 'A':
+					opt_abort = true;
+					break;
+				case 'b':
+#ifdef MALLOC_BALANCE
+					opt_balance_threshold >>= 1;
+#endif
+					break;
+				case 'B':
+#ifdef MALLOC_BALANCE
+					if (opt_balance_threshold == 0)
+						opt_balance_threshold = 1;
+					else if ((opt_balance_threshold << 1)
+					    > opt_balance_threshold)
+						opt_balance_threshold <<= 1;
+#endif
+					break;
+				case 'c':
+					if (opt_cspace_max_2pow - 1 >
+					    opt_qspace_max_2pow &&
+					    opt_cspace_max_2pow >
+					    CACHELINE_2POW)
+						opt_cspace_max_2pow--;
+					break;
+				case 'C':
+					if (opt_cspace_max_2pow < pagesize_2pow
+					    - 1)
+						opt_cspace_max_2pow++;
+					break;
+				case 'd':
+#ifdef MALLOC_DSS
+					opt_dss = false;
+#endif
+					break;
+				case 'D':
+#ifdef MALLOC_DSS
+					opt_dss = true;
+#endif
+					break;
+				case 'f':
+					opt_dirty_max >>= 1;
+					break;
+				case 'F':
+					if (opt_dirty_max == 0)
+						opt_dirty_max = 1;
+					else if ((opt_dirty_max << 1) != 0)
+						opt_dirty_max <<= 1;
+					break;
+#ifdef MALLOC_MAG
+				case 'g':
+					opt_mag = false;
+					break;
+				case 'G':
+					opt_mag = true;
+					break;
+#endif
+				case 'j':
+					opt_junk = false;
+					break;
+				case 'J':
+					opt_junk = true;
+					break;
+				case 'k':
+					/*
+					 * Chunks always require at least one
+					 * header page, so chunks can never be
+					 * smaller than two pages.
+					 */
+					if (opt_chunk_2pow > pagesize_2pow + 1)
+						opt_chunk_2pow--;
+					break;
+				case 'K':
+					if (opt_chunk_2pow + 1 <
+					    (sizeof(size_t) << 3))
+						opt_chunk_2pow++;
+					break;
+				case 'm':
+#ifdef MALLOC_DSS
+					opt_mmap = false;
+#endif
+					break;
+				case 'M':
+#ifdef MALLOC_DSS
+					opt_mmap = true;
+#endif
+					break;
+				case 'n':
+					opt_narenas_lshift--;
+					break;
+				case 'N':
+					opt_narenas_lshift++;
+					break;
+				case 'p':
+					opt_print_stats = false;
+					break;
+				case 'P':
+					opt_print_stats = true;
+					break;
+				case 'q':
+					if (opt_qspace_max_2pow > QUANTUM_2POW)
+						opt_qspace_max_2pow--;
+					break;
+				case 'Q':
+					if (opt_qspace_max_2pow + 1 <
+					    opt_cspace_max_2pow)
+						opt_qspace_max_2pow++;
+					break;
+#ifdef MALLOC_MAG
+				case 'R':
+					if (opt_mag_size_2pow + 1 < (8U <<
+					    SIZEOF_PTR_2POW))
+						opt_mag_size_2pow++;
+					break;
+				case 'r':
+					/*
+					 * Make sure there's always at least
+					 * one round per magazine.
+					 */
+					if ((1U << (opt_mag_size_2pow-1)) >=
+					    sizeof(mag_t))
+						opt_mag_size_2pow--;
+					break;
+#endif
+				case 'u':
+					opt_utrace = false;
+					break;
+				case 'U':
+					opt_utrace = true;
+					break;
+				case 'v':
+					opt_sysv = false;
+					break;
+				case 'V':
+					opt_sysv = true;
+					break;
+				case 'x':
+					opt_xmalloc = false;
+					break;
+				case 'X':
+					opt_xmalloc = true;
+					break;
+				case 'z':
+					opt_zero = false;
+					break;
+				case 'Z':
+					opt_zero = true;
+					break;
+				default: {
+					char cbuf[2];
+
+					cbuf[0] = opts[j];
+					cbuf[1] = '\0';
+					_malloc_message(_getprogname(),
+					    ": (malloc) Unsupported character "
+					    "in malloc options: '", cbuf,
+					    "'\n");
+				}
+				}
+			}
+		}
+	}
+
+#ifdef MALLOC_DSS
+	/* Make sure that there is some method for acquiring memory. */
+	if (opt_dss == false && opt_mmap == false)
+		opt_mmap = true;
+#endif
+
+	/* Take care to call atexit() only once. */
+	if (opt_print_stats) {
+		/* Print statistics at exit. */
+		atexit(malloc_print_stats);
+	}
+
+	/* Register fork handlers. */
+	pthread_atfork(_malloc_prefork, _malloc_postfork, _malloc_postfork);
+
+#ifdef MALLOC_MAG
+	/*
+	 * Calculate the actual number of rounds per magazine, taking into
+	 * account header overhead.
+	 */
+	max_rounds = (1LLU << (opt_mag_size_2pow - SIZEOF_PTR_2POW)) -
+	    (sizeof(mag_t) >> SIZEOF_PTR_2POW) + 1;
+#endif
+
+	/* Set variables according to the value of opt_[qc]space_max_2pow. */
+	qspace_max = (1U << opt_qspace_max_2pow);
+	cspace_min = CACHELINE_CEILING(qspace_max);
+	if (cspace_min == qspace_max)
+		cspace_min += CACHELINE;
+	cspace_max = (1U << opt_cspace_max_2pow);
+	sspace_min = SUBPAGE_CEILING(cspace_max);
+	if (sspace_min == cspace_max)
+		sspace_min += SUBPAGE;
+	assert(sspace_min < pagesize);
+	sspace_max = pagesize - SUBPAGE;
+
+#ifdef MALLOC_TINY
+	assert(QUANTUM_2POW >= TINY_MIN_2POW);
+#endif
+	assert(ntbins <= QUANTUM_2POW);
+	nqbins = qspace_max >> QUANTUM_2POW;
+	ncbins = ((cspace_max - cspace_min) >> CACHELINE_2POW) + 1;
+	nsbins = ((sspace_max - sspace_min) >> SUBPAGE_2POW) + 1;
+	nbins = ntbins + nqbins + ncbins + nsbins;
+
+	if (size2bin_init()) {
+		malloc_mutex_unlock(&init_lock);
+		return (true);
+	}
+
+	/* Set variables according to the value of opt_chunk_2pow. */
+	chunksize = (1LU << opt_chunk_2pow);
+	chunksize_mask = chunksize - 1;
+	chunk_npages = (chunksize >> pagesize_2pow);
+	{
+		size_t header_size;
+
+		/*
+		 * Compute the header size such that it is large enough to
+		 * contain the page map.
+		 */
+		header_size = sizeof(arena_chunk_t) +
+		    (sizeof(arena_chunk_map_t) * (chunk_npages - 1));
+		arena_chunk_header_npages = (header_size >> pagesize_2pow) +
+		    ((header_size & pagesize_mask) != 0);
+	}
+	arena_maxclass = chunksize - (arena_chunk_header_npages <<
+	    pagesize_2pow);
+
+	UTRACE(0, 0, 0);
+
+#ifdef MALLOC_STATS
+	memset(&stats_chunks, 0, sizeof(chunk_stats_t));
+#endif
+
+	/* Various sanity checks that regard configuration. */
+	assert(chunksize >= pagesize);
+
+	/* Initialize chunks data. */
+	if (malloc_mutex_init(&huge_mtx)) {
+		malloc_mutex_unlock(&init_lock);
+		return (true);
+	}
+	extent_tree_ad_new(&huge);
+#ifdef MALLOC_DSS
+	if (malloc_mutex_init(&dss_mtx)) {
+		malloc_mutex_unlock(&init_lock);
+		return (true);
+	}
+	dss_base = sbrk(0);
+	dss_prev = dss_base;
+	dss_max = dss_base;
+	extent_tree_szad_new(&dss_chunks_szad);
+	extent_tree_ad_new(&dss_chunks_ad);
+#endif
+#ifdef MALLOC_STATS
+	huge_nmalloc = 0;
+	huge_ndalloc = 0;
+	huge_allocated = 0;
+#endif
+
+	/* Initialize base allocation data structures. */
+#ifdef MALLOC_STATS
+	base_mapped = 0;
+#endif
+#ifdef MALLOC_DSS
+	/*
+	 * Allocate a base chunk here, since it doesn't actually have to be
+	 * chunk-aligned.  Doing this before allocating any other chunks allows
+	 * the use of space that would otherwise be wasted.
+	 */
+	if (opt_dss)
+		base_pages_alloc(0);
+#endif
+	base_nodes = NULL;
+	if (malloc_mutex_init(&base_mtx)) {
+		malloc_mutex_unlock(&init_lock);
+		return (true);
+	}
+
+	if (ncpus > 1) {
+		/*
+		 * For SMP systems, create twice as many arenas as there are
+		 * CPUs by default.
+		 */
+		opt_narenas_lshift++;
+	}
+
+	/* Determine how many arenas to use. */
+	narenas = ncpus;
+	if (opt_narenas_lshift > 0) {
+		if ((narenas << opt_narenas_lshift) > narenas)
+			narenas <<= opt_narenas_lshift;
+		/*
+		 * Make sure not to exceed the limits of what base_alloc() can
+		 * handle.
+		 */
+		if (narenas * sizeof(arena_t *) > chunksize)
+			narenas = chunksize / sizeof(arena_t *);
+	} else if (opt_narenas_lshift < 0) {
+		if ((narenas >> -opt_narenas_lshift) < narenas)
+			narenas >>= -opt_narenas_lshift;
+		/* Make sure there is at least one arena. */
+		if (narenas == 0)
+			narenas = 1;
+	}
+#ifdef MALLOC_BALANCE
+	assert(narenas != 0);
+	for (narenas_2pow = 0;
+	     (narenas >> (narenas_2pow + 1)) != 0;
+	     narenas_2pow++);
+#endif
+
+#ifdef NO_TLS
+	if (narenas > 1) {
+		static const unsigned primes[] = {1, 3, 5, 7, 11, 13, 17, 19,
+		    23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83,
+		    89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149,
+		    151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211,
+		    223, 227, 229, 233, 239, 241, 251, 257, 263};
+		unsigned nprimes, parenas;
+
+		/*
+		 * Pick a prime number of hash arenas that is more than narenas
+		 * so that direct hashing of pthread_self() pointers tends to
+		 * spread allocations evenly among the arenas.
+		 */
+		assert((narenas & 1) == 0); /* narenas must be even. */
+		nprimes = (sizeof(primes) >> SIZEOF_INT_2POW);
+		parenas = primes[nprimes - 1]; /* In case not enough primes. */
+		for (i = 1; i < nprimes; i++) {
+			if (primes[i] > narenas) {
+				parenas = primes[i];
+				break;
+			}
+		}
+		narenas = parenas;
+	}
+#endif
+
+#ifndef NO_TLS
+#  ifndef MALLOC_BALANCE
+	next_arena = 0;
+#  endif
+#endif
+
+	/* Allocate and initialize arenas. */
+	arenas = (arena_t **)base_alloc(sizeof(arena_t *) * narenas);
+	if (arenas == NULL) {
+		malloc_mutex_unlock(&init_lock);
+		return (true);
+	}
+	/*
+	 * Zero the array.  In practice, this should always be pre-zeroed,
+	 * since it was just mmap()ed, but let's be sure.
+	 */
+	memset(arenas, 0, sizeof(arena_t *) * narenas);
+
+	/*
+	 * Initialize one arena here.  The rest are lazily created in
+	 * choose_arena_hard().
+	 */
+	arenas_extend(0);
+	if (arenas[0] == NULL) {
+		malloc_mutex_unlock(&init_lock);
+		return (true);
+	}
+#ifndef NO_TLS
+	/*
+	 * Assign the initial arena to the initial thread, in order to avoid
+	 * spurious creation of an extra arena if the application switches to
+	 * threaded mode.
+	 */
+	arenas_map = arenas[0];
+#endif
+	/*
+	 * Seed here for the initial thread, since choose_arena_hard() is only
+	 * called for other threads.  The seed value doesn't really matter.
+	 */
+#ifdef MALLOC_BALANCE
+	SPRN(balance, 42);
+#endif
+
+	malloc_spin_init(&arenas_lock);
+
+	malloc_initialized = true;
+	malloc_mutex_unlock(&init_lock);
+	return (false);
+}
+
+/*
+ * End general internal functions.
+ */
+/******************************************************************************/
+/*
+ * Begin malloc(3)-compatible functions.
+ */
+
+void *
+malloc(size_t size)
+{
+	void *ret;
+
+	if (malloc_init()) {
+		ret = NULL;
+		goto RETURN;
+	}
+
+	if (size == 0) {
+		if (opt_sysv == false)
+			size = 1;
+		else {
+			ret = NULL;
+			goto RETURN;
+		}
+	}
+
+	ret = imalloc(size);
+
+RETURN:
+	if (ret == NULL) {
+		if (opt_xmalloc) {
+			_malloc_message(_getprogname(),
+			    ": (malloc) Error in malloc(): out of memory\n", "",
+			    "");
+			abort();
+		}
+		errno = ENOMEM;
+	}
+
+	UTRACE(0, size, ret);
+	return (ret);
+}
+
+int
+posix_memalign(void **memptr, size_t alignment, size_t size)
+{
+	int ret;
+	void *result;
+
+	if (malloc_init())
+		result = NULL;
+	else {
+		/* Make sure that alignment is a large enough power of 2. */
+		if (((alignment - 1) & alignment) != 0
+		    || alignment < sizeof(void *)) {
+			if (opt_xmalloc) {
+				_malloc_message(_getprogname(),
+				    ": (malloc) Error in posix_memalign(): "
+				    "invalid alignment\n", "", "");
+				abort();
+			}
+			result = NULL;
+			ret = EINVAL;
+			goto RETURN;
+		}
+
+		result = ipalloc(alignment, size);
+	}
+
+	if (result == NULL) {
+		if (opt_xmalloc) {
+			_malloc_message(_getprogname(),
+			": (malloc) Error in posix_memalign(): out of memory\n",
+			"", "");
+			abort();
+		}
+		ret = ENOMEM;
+		goto RETURN;
+	}
+
+	*memptr = result;
+	ret = 0;
+
+RETURN:
+	UTRACE(0, size, result);
+	return (ret);
+}
+
+void *
+calloc(size_t num, size_t size)
+{
+	void *ret;
+	size_t num_size;
+
+	if (malloc_init()) {
+		num_size = 0;
+		ret = NULL;
+		goto RETURN;
+	}
+
+	num_size = num * size;
+	if (num_size == 0) {
+		if ((opt_sysv == false) && ((num == 0) || (size == 0)))
+			num_size = 1;
+		else {
+			ret = NULL;
+			goto RETURN;
+		}
+	/*
+	 * Try to avoid division here.  We know that it isn't possible to
+	 * overflow during multiplication if neither operand uses any of the
+	 * most significant half of the bits in a size_t.
+	 */
+	} else if (((num | size) & (SIZE_T_MAX << (sizeof(size_t) << 2)))
+	    && (num_size / size != num)) {
+		/* size_t overflow. */
+		ret = NULL;
+		goto RETURN;
+	}
+
+	ret = icalloc(num_size);
+
+RETURN:
+	if (ret == NULL) {
+		if (opt_xmalloc) {
+			_malloc_message(_getprogname(),
+			    ": (malloc) Error in calloc(): out of memory\n", "",
+			    "");
+			abort();
+		}
+		errno = ENOMEM;
+	}
+
+	UTRACE(0, num_size, ret);
+	return (ret);
+}
+
+void *
+realloc(void *ptr, size_t size)
+{
+	void *ret;
+
+	if (size == 0) {
+		if (opt_sysv == false)
+			size = 1;
+		else {
+			if (ptr != NULL)
+				idalloc(ptr);
+			ret = NULL;
+			goto RETURN;
+		}
+	}
+
+	if (ptr != NULL) {
+		assert(malloc_initialized);
+
+		ret = iralloc(ptr, size);
+
+		if (ret == NULL) {
+			if (opt_xmalloc) {
+				_malloc_message(_getprogname(),
+				    ": (malloc) Error in realloc(): out of "
+				    "memory\n", "", "");
+				abort();
+			}
+			errno = ENOMEM;
+		}
+	} else {
+		if (malloc_init())
+			ret = NULL;
+		else
+			ret = imalloc(size);
+
+		if (ret == NULL) {
+			if (opt_xmalloc) {
+				_malloc_message(_getprogname(),
+				    ": (malloc) Error in realloc(): out of "
+				    "memory\n", "", "");
+				abort();
+			}
+			errno = ENOMEM;
+		}
+	}
+
+RETURN:
+	UTRACE(ptr, size, ret);
+	return (ret);
+}
+
+void
+free(void *ptr)
+{
+
+	UTRACE(ptr, 0, 0);
+	if (ptr != NULL) {
+		assert(malloc_initialized);
+
+		idalloc(ptr);
+	}
+}
+
+/*
+ * End malloc(3)-compatible functions.
+ */
+/******************************************************************************/
+/*
+ * Begin non-standard functions.
+ */
+
+size_t
+malloc_usable_size(const void *ptr)
+{
+
+	assert(ptr != NULL);
+
+	return (isalloc(ptr));
+}
+
+/*
+ * End non-standard functions.
+ */
+/******************************************************************************/
+/*
+ * Begin library-private functions.
+ */
+
+/******************************************************************************/
+/*
+ * Begin thread cache.
+ */
+
+/*
+ * We provide an unpublished interface in order to receive notifications from
+ * the pthreads library whenever a thread exits.  This allows us to clean up
+ * thread caches.
+ */
+void
+_malloc_thread_cleanup(void)
+{
+
+#ifdef MALLOC_MAG
+	if (mag_rack != NULL) {
+		assert(mag_rack != (void *)-1);
+		mag_rack_destroy(mag_rack);
+#ifdef MALLOC_DEBUG
+		mag_rack = (void *)-1;
+#endif
+	}
+#endif
+}
+
+/*
+ * The following functions are used by threading libraries for protection of
+ * malloc during fork().  These functions are only called if the program is
+ * running in threaded mode, so there is no need to check whether the program
+ * is threaded here.
+ */
+
+void
+_malloc_prefork(void)
+{
+	unsigned i;
+
+	/* Acquire all mutexes in a safe order. */
+
+	malloc_spin_lock(&arenas_lock);
+	for (i = 0; i < narenas; i++) {
+		if (arenas[i] != NULL)
+			malloc_spin_lock(&arenas[i]->lock);
+	}
+	malloc_spin_unlock(&arenas_lock);
+
+	malloc_mutex_lock(&base_mtx);
+
+	malloc_mutex_lock(&huge_mtx);
+
+#ifdef MALLOC_DSS
+	malloc_mutex_lock(&dss_mtx);
+#endif
+}
+
+void
+_malloc_postfork(void)
+{
+	unsigned i;
+
+	/* Release all mutexes, now that fork() has completed. */
+
+#ifdef MALLOC_DSS
+	malloc_mutex_unlock(&dss_mtx);
+#endif
+
+	malloc_mutex_unlock(&huge_mtx);
+
+	malloc_mutex_unlock(&base_mtx);
+
+	malloc_spin_lock(&arenas_lock);
+	for (i = 0; i < narenas; i++) {
+		if (arenas[i] != NULL)
+			malloc_spin_unlock(&arenas[i]->lock);
+	}
+	malloc_spin_unlock(&arenas_lock);
+}
+
+/*
+ * End library-private functions.
+ */
+/******************************************************************************/

Added: trunk/varnish-cache/lib/libjemalloc/malloc.3
===================================================================
--- trunk/varnish-cache/lib/libjemalloc/malloc.3	                        (rev 0)
+++ trunk/varnish-cache/lib/libjemalloc/malloc.3	2008-09-24 12:41:27 UTC (rev 3215)
@@ -0,0 +1,584 @@
+.\" Copyright (c) 1980, 1991, 1993
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" This code is derived from software contributed to Berkeley by
+.\" the American National Standards Committee X3, on Information
+.\" Processing Systems.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"     @(#)malloc.3	8.1 (Berkeley) 6/4/93
+.\" $FreeBSD: head/lib/libc/stdlib/malloc.3 182225 2008-08-27 02:00:53Z jasone $
+.\"
+.Dd August 26, 2008
+.Dt MALLOC 3
+.Os
+.Sh NAME
+.Nm malloc , calloc , realloc , free , reallocf , malloc_usable_size
+.Nd general purpose memory allocation functions
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.In stdlib.h
+.Ft void *
+.Fn malloc "size_t size"
+.Ft void *
+.Fn calloc "size_t number" "size_t size"
+.Ft void *
+.Fn realloc "void *ptr" "size_t size"
+.Ft void *
+.Fn reallocf "void *ptr" "size_t size"
+.Ft void
+.Fn free "void *ptr"
+.Ft const char *
+.Va _malloc_options ;
+.Ft void
+.Fo \*(lp*_malloc_message\*(rp
+.Fa "const char *p1" "const char *p2" "const char *p3" "const char *p4"
+.Fc
+.In malloc_np.h
+.Ft size_t
+.Fn malloc_usable_size "const void *ptr"
+.Sh DESCRIPTION
+The
+.Fn malloc
+function allocates
+.Fa size
+bytes of uninitialized memory.
+The allocated space is suitably aligned (after possible pointer coercion)
+for storage of any type of object.
+.Pp
+The
+.Fn calloc
+function allocates space for
+.Fa number
+objects,
+each
+.Fa size
+bytes in length.
+The result is identical to calling
+.Fn malloc
+with an argument of
+.Dq "number * size" ,
+with the exception that the allocated memory is explicitly initialized
+to zero bytes.
+.Pp
+The
+.Fn realloc
+function changes the size of the previously allocated memory referenced by
+.Fa ptr
+to
+.Fa size
+bytes.
+The contents of the memory are unchanged up to the lesser of the new and
+old sizes.
+If the new size is larger,
+the contents of the newly allocated portion of the memory are undefined.
+Upon success, the memory referenced by
+.Fa ptr
+is freed and a pointer to the newly allocated memory is returned.
+Note that
+.Fn realloc
+and
+.Fn reallocf
+may move the memory allocation, resulting in a different return value than
+.Fa ptr .
+If
+.Fa ptr
+is
+.Dv NULL ,
+the
+.Fn realloc
+function behaves identically to
+.Fn malloc
+for the specified size.
+.Pp
+The
+.Fn reallocf
+function is identical to the
+.Fn realloc
+function, except that it
+will free the passed pointer when the requested memory cannot be allocated.
+This is a
+.Fx
+specific API designed to ease the problems with traditional coding styles
+for realloc causing memory leaks in libraries.
+.Pp
+The
+.Fn free
+function causes the allocated memory referenced by
+.Fa ptr
+to be made available for future allocations.
+If
+.Fa ptr
+is
+.Dv NULL ,
+no action occurs.
+.Pp
+The
+.Fn malloc_usable_size
+function returns the usable size of the allocation pointed to by
+.Fa ptr .
+The return value may be larger than the size that was requested during
+allocation.
+The
+.Fn malloc_usable_size
+function is not a mechanism for in-place
+.Fn realloc ;
+rather it is provided solely as a tool for introspection purposes.
+Any discrepancy between the requested allocation size and the size reported by
+.Fn malloc_usable_size
+should not be depended on, since such behavior is entirely
+implementation-dependent.
+.Sh TUNING
+Once, when the first call is made to one of these memory allocation
+routines, various flags will be set or reset, which affects the
+workings of this allocator implementation.
+.Pp
+The
+.Dq name
+of the file referenced by the symbolic link named
+.Pa /etc/malloc.conf ,
+the value of the environment variable
+.Ev MALLOC_OPTIONS ,
+and the string pointed to by the global variable
+.Va _malloc_options
+will be interpreted, in that order, from left to right as flags.
+.Pp
+Each flag is a single letter, optionally prefixed by a non-negative base 10
+integer repetition count.
+For example,
+.Dq 3N
+is equivalent to
+.Dq NNN .
+Some flags control parameter magnitudes, where uppercase increases the
+magnitude, and lowercase decreases the magnitude.
+Other flags control boolean parameters, where uppercase indicates that a
+behavior is set, or on, and lowercase means that a behavior is not set, or off.
+.Bl -tag -width indent
+.It A
+All warnings (except for the warning about unknown
+flags being set) become fatal.
+The process will call
+.Xr abort 3
+in these cases.
+.It B
+Double/halve the per-arena lock contention threshold at which a thread is
+randomly re-assigned to an arena.
+This dynamic load balancing tends to push threads away from highly contended
+arenas, which avoids worst case contention scenarios in which threads
+disproportionately utilize arenas.
+However, due to the highly dynamic load that applications may place on the
+allocator, it is impossible for the allocator to know in advance how sensitive
+it should be to contention over arenas.
+Therefore, some applications may benefit from increasing or decreasing this
+threshold parameter.
+This option is not available for some configurations (non-PIC).
+.It C
+Double/halve the size of the maximum size class that is a multiple of the
+cacheline size (64).
+Above this size, subpage spacing (256 bytes) is used for size classes.
+The default value is 512 bytes.
+.It D
+Use
+.Xr sbrk 2
+to acquire memory in the data storage segment (DSS).
+This option is enabled by default.
+See the
+.Dq M
+option for related information and interactions.
+.It F
+Double/halve the per-arena maximum number of dirty unused pages that are
+allowed to accumulate before informing the kernel about at least half of those
+pages via
+.Xr madvise 2 .
+This provides the kernel with sufficient information to recycle dirty pages if
+physical memory becomes scarce and the pages remain unused.
+The default is 512 pages per arena;
+.Ev MALLOC_OPTIONS=10f
+will prevent any dirty unused pages from accumulating.
+.It G
+When there are multiple threads, use thread-specific caching for objects that
+are smaller than one page.
+This option is enabled by default.
+Thread-specific caching allows many allocations to be satisfied without
+performing any thread synchronization, at the cost of increased memory use.
+See the
+.Dq R
+option for related tuning information.
+This option is not available for some configurations (non-PIC).
+.It J
+Each byte of new memory allocated by
+.Fn malloc ,
+.Fn realloc
+or
+.Fn reallocf
+will be initialized to 0xa5.
+All memory returned by
+.Fn free ,
+.Fn realloc
+or
+.Fn reallocf
+will be initialized to 0x5a.
+This is intended for debugging and will impact performance negatively.
+.It K
+Double/halve the virtual memory chunk size.
+The default chunk size is 1 MB.
+.It M
+Use
+.Xr mmap 2
+to acquire anonymously mapped memory.
+This option is enabled by default.
+If both the
+.Dq D
+and
+.Dq M
+options are enabled, the allocator prefers the DSS over anonymous mappings,
+but allocation only fails if memory cannot be acquired via either method.
+If neither option is enabled, then the
+.Dq M
+option is implicitly enabled in order to assure that there is a method for
+acquiring memory.
+.It N
+Double/halve the number of arenas.
+The default number of arenas is two times the number of CPUs, or one if there
+is a single CPU.
+.It P
+Various statistics are printed at program exit via an
+.Xr atexit 3
+function.
+This has the potential to cause deadlock for a multi-threaded process that exits
+while one or more threads are executing in the memory allocation functions.
+Therefore, this option should only be used with care; it is primarily intended
+as a performance tuning aid during application development.
+.It Q
+Double/halve the size of the maximum size class that is a multiple of the
+quantum (8 or 16 bytes, depending on architecture).
+Above this size, cacheline spacing is used for size classes.
+The default value is 128 bytes.
+.It R
+Double/halve magazine size, which approximately doubles/halves the number of
+rounds in each magazine.
+Magazines are used by the thread-specific caching machinery to acquire and
+release objects in bulk.
+Increasing the magazine size decreases locking overhead, at the expense of
+increased memory usage.
+This option is not available for some configurations (non-PIC).
+.It U
+Generate
+.Dq utrace
+entries for
+.Xr ktrace 1 ,
+for all operations.
+Consult the source for details on this option.
+.It V
+Attempting to allocate zero bytes will return a
+.Dv NULL
+pointer instead of
+a valid pointer.
+(The default behavior is to make a minimal allocation and return a
+pointer to it.)
+This option is provided for System V compatibility.
+This option is incompatible with the
+.Dq X
+option.
+.It X
+Rather than return failure for any allocation function,
+display a diagnostic message on
+.Dv stderr
+and cause the program to drop
+core (using
+.Xr abort 3 ) .
+This option should be set at compile time by including the following in
+the source code:
+.Bd -literal -offset indent
+_malloc_options = "X";
+.Ed
+.It Z
+Each byte of new memory allocated by
+.Fn malloc ,
+.Fn realloc
+or
+.Fn reallocf
+will be initialized to 0.
+Note that this initialization only happens once for each byte, so
+.Fn realloc
+and
+.Fn reallocf
+calls do not zero memory that was previously allocated.
+This is intended for debugging and will impact performance negatively.
+.El
+.Pp
+The
+.Dq J
+and
+.Dq Z
+options are intended for testing and debugging.
+An application which changes its behavior when these options are used
+is flawed.
+.Sh IMPLEMENTATION NOTES
+Traditionally, allocators have used
+.Xr sbrk 2
+to obtain memory, which is suboptimal for several reasons, including race
+conditions, increased fragmentation, and artificial limitations on maximum
+usable memory.
+This allocator uses both
+.Xr sbrk 2
+and
+.Xr mmap 2
+by default, but it can be configured at run time to use only one or the other.
+If resource limits are not a primary concern, the preferred configuration is
+.Ev MALLOC_OPTIONS=dM
+or
+.Ev MALLOC_OPTIONS=DM .
+When so configured, the
+.Ar datasize
+resource limit has little practical effect for typical applications; use
+.Ev MALLOC_OPTIONS=Dm
+if that is a concern.
+Regardless of allocator configuration, the
+.Ar vmemoryuse
+resource limit can be used to bound the total virtual memory used by a
+process, as described in
+.Xr limits 1 .
+.Pp
+This allocator uses multiple arenas in order to reduce lock contention for
+threaded programs on multi-processor systems.
+This works well with regard to threading scalability, but incurs some costs.
+There is a small fixed per-arena overhead, and additionally, arenas manage
+memory completely independently of each other, which means a small fixed
+increase in overall memory fragmentation.
+These overheads are not generally an issue, given the number of arenas normally
+used.
+Note that using substantially more arenas than the default is not likely to
+improve performance, mainly due to reduced cache performance.
+However, it may make sense to reduce the number of arenas if an application
+does not make much use of the allocation functions.
+.Pp
+In addition to multiple arenas, this allocator supports thread-specific
+caching for small objects (smaller than one page), in order to make it
+possible to completely avoid synchronization for most small allocation requests.
+Such caching allows very fast allocation in the common case, but it increases
+memory usage and fragmentation, since a bounded number of objects can remain
+allocated in each thread cache.
+.Pp
+Memory is conceptually broken into equal-sized chunks, where the chunk size is
+a power of two that is greater than the page size.
+Chunks are always aligned to multiples of the chunk size.
+This alignment makes it possible to find metadata for user objects very
+quickly.
+.Pp
+User objects are broken into three categories according to size: small, large,
+and huge.
+Small objects are smaller than one page.
+Large objects are smaller than the chunk size.
+Huge objects are a multiple of the chunk size.
+Small and large objects are managed by arenas; huge objects are managed
+separately in a single data structure that is shared by all threads.
+Huge objects are used by applications infrequently enough that this single
+data structure is not a scalability issue.
+.Pp
+Each chunk that is managed by an arena tracks its contents as runs of
+contiguous pages (unused, backing a set of small objects, or backing one large
+object).
+The combination of chunk alignment and chunk page maps makes it possible to
+determine all metadata regarding small and large allocations in constant time.
+.Pp
+Small objects are managed in groups by page runs.
+Each run maintains a bitmap that tracks which regions are in use.
+Allocation requests that are no more than half the quantum (8 or 16, depending
+on architecture) are rounded up to the nearest power of two.
+Allocation requests that are more than half the quantum, but no more than the
+minimum cacheline-multiple size class (see the
+.Dq Q
+option) are rounded up to the nearest multiple of the quantum.
+Allocation requests that are more than the minumum cacheline-multiple size
+class, but no more than the minimum subpage-multiple size class (see the
+.Dq C
+option) are rounded up to the nearest multiple of the cacheline size (64).
+Allocation requests that are more than the minimum subpage-multiple size class
+are rounded up to the nearest multiple of the subpage size (256).
+Allocation requests that are more than one page, but small enough to fit in
+an arena-managed chunk (see the
+.Dq K
+option), are rounded up to the nearest run size.
+Allocation requests that are too large to fit in an arena-managed chunk are
+rounded up to the nearest multiple of the chunk size.
+.Pp
+Allocations are packed tightly together, which can be an issue for
+multi-threaded applications.
+If you need to assure that allocations do not suffer from cacheline sharing,
+round your allocation requests up to the nearest multiple of the cacheline
+size.
+.Sh DEBUGGING MALLOC PROBLEMS
+The first thing to do is to set the
+.Dq A
+option.
+This option forces a coredump (if possible) at the first sign of trouble,
+rather than the normal policy of trying to continue if at all possible.
+.Pp
+It is probably also a good idea to recompile the program with suitable
+options and symbols for debugger support.
+.Pp
+If the program starts to give unusual results, coredump or generally behave
+differently without emitting any of the messages mentioned in the next
+section, it is likely because it depends on the storage being filled with
+zero bytes.
+Try running it with the
+.Dq Z
+option set;
+if that improves the situation, this diagnosis has been confirmed.
+If the program still misbehaves,
+the likely problem is accessing memory outside the allocated area.
+.Pp
+Alternatively, if the symptoms are not easy to reproduce, setting the
+.Dq J
+option may help provoke the problem.
+.Pp
+In truly difficult cases, the
+.Dq U
+option, if supported by the kernel, can provide a detailed trace of
+all calls made to these functions.
+.Pp
+Unfortunately this implementation does not provide much detail about
+the problems it detects; the performance impact for storing such information
+would be prohibitive.
+There are a number of allocator implementations available on the Internet
+which focus on detecting and pinpointing problems by trading performance for
+extra sanity checks and detailed diagnostics.
+.Sh DIAGNOSTIC MESSAGES
+If any of the memory allocation/deallocation functions detect an error or
+warning condition, a message will be printed to file descriptor
+.Dv STDERR_FILENO .
+Errors will result in the process dumping core.
+If the
+.Dq A
+option is set, all warnings are treated as errors.
+.Pp
+The
+.Va _malloc_message
+variable allows the programmer to override the function which emits
+the text strings forming the errors and warnings if for some reason
+the
+.Dv stderr
+file descriptor is not suitable for this.
+Please note that doing anything which tries to allocate memory in
+this function is likely to result in a crash or deadlock.
+.Pp
+All messages are prefixed by
+.Dq Ao Ar progname Ac Ns Li : (malloc) .
+.Sh RETURN VALUES
+The
+.Fn malloc
+and
+.Fn calloc
+functions return a pointer to the allocated memory if successful; otherwise
+a
+.Dv NULL
+pointer is returned and
+.Va errno
+is set to
+.Er ENOMEM .
+.Pp
+The
+.Fn realloc
+and
+.Fn reallocf
+functions return a pointer, possibly identical to
+.Fa ptr ,
+to the allocated memory
+if successful; otherwise a
+.Dv NULL
+pointer is returned, and
+.Va errno
+is set to
+.Er ENOMEM
+if the error was the result of an allocation failure.
+The
+.Fn realloc
+function always leaves the original buffer intact
+when an error occurs, whereas
+.Fn reallocf
+deallocates it in this case.
+.Pp
+The
+.Fn free
+function returns no value.
+.Pp
+The
+.Fn malloc_usable_size
+function returns the usable size of the allocation pointed to by
+.Fa ptr .
+.Sh ENVIRONMENT
+The following environment variables affect the execution of the allocation
+functions:
+.Bl -tag -width ".Ev MALLOC_OPTIONS"
+.It Ev MALLOC_OPTIONS
+If the environment variable
+.Ev MALLOC_OPTIONS
+is set, the characters it contains will be interpreted as flags to the
+allocation functions.
+.El
+.Sh EXAMPLES
+To dump core whenever a problem occurs:
+.Pp
+.Bd -literal -offset indent
+ln -s 'A' /etc/malloc.conf
+.Ed
+.Pp
+To specify in the source that a program does no return value checking
+on calls to these functions:
+.Bd -literal -offset indent
+_malloc_options = "X";
+.Ed
+.Sh SEE ALSO
+.Xr limits 1 ,
+.Xr madvise 2 ,
+.Xr mmap 2 ,
+.Xr sbrk 2 ,
+.Xr alloca 3 ,
+.Xr atexit 3 ,
+.Xr getpagesize 3 ,
+.Xr memory 3 ,
+.Xr posix_memalign 3
+.Sh STANDARDS
+The
+.Fn malloc ,
+.Fn calloc ,
+.Fn realloc
+and
+.Fn free
+functions conform to
+.St -isoC .
+.Sh HISTORY
+The
+.Fn reallocf
+function first appeared in
+.Fx 3.0 .
+.Pp
+The
+.Fn malloc_usable_size
+function first appeared in
+.Fx 7.0 .

Added: trunk/varnish-cache/lib/libjemalloc/malloc.c
===================================================================
--- trunk/varnish-cache/lib/libjemalloc/malloc.c	                        (rev 0)
+++ trunk/varnish-cache/lib/libjemalloc/malloc.c	2008-09-24 12:41:27 UTC (rev 3215)
@@ -0,0 +1,5589 @@
+/*-
+ * Copyright (C) 2006-2008 Jason Evans <jasone at FreeBSD.org>.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice(s), this list of conditions and the following disclaimer as
+ *    the first lines of this file unmodified other than the possible
+ *    addition of one or more copyright notices.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice(s), this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *******************************************************************************
+ *
+ * This allocator implementation is designed to provide scalable performance
+ * for multi-threaded programs on multi-processor systems.  The following
+ * features are included for this purpose:
+ *
+ *   + Multiple arenas are used if there are multiple CPUs, which reduces lock
+ *     contention and cache sloshing.
+ *
+ *   + Thread-specific caching is used if there are multiple threads, which
+ *     reduces the amount of locking.
+ *
+ *   + Cache line sharing between arenas is avoided for internal data
+ *     structures.
+ *
+ *   + Memory is managed in chunks and runs (chunks can be split into runs),
+ *     rather than as individual pages.  This provides a constant-time
+ *     mechanism for associating allocations with particular arenas.
+ *
+ * Allocation requests are rounded up to the nearest size class, and no record
+ * of the original request size is maintained.  Allocations are broken into
+ * categories according to size class.  Assuming runtime defaults, 4 kB pages
+ * and a 16 byte quantum on a 32-bit system, the size classes in each category
+ * are as follows:
+ *
+ *   |=======================================|
+ *   | Category | Subcategory      |    Size |
+ *   |=======================================|
+ *   | Small    | Tiny             |       2 |
+ *   |          |                  |       4 |
+ *   |          |                  |       8 |
+ *   |          |------------------+---------|
+ *   |          | Quantum-spaced   |      16 |
+ *   |          |                  |      32 |
+ *   |          |                  |      48 |
+ *   |          |                  |     ... |
+ *   |          |                  |      96 |
+ *   |          |                  |     112 |
+ *   |          |                  |     128 |
+ *   |          |------------------+---------|
+ *   |          | Cacheline-spaced |     192 |
+ *   |          |                  |     256 |
+ *   |          |                  |     320 |
+ *   |          |                  |     384 |
+ *   |          |                  |     448 |
+ *   |          |                  |     512 |
+ *   |          |------------------+---------|
+ *   |          | Sub-page         |     760 |
+ *   |          |                  |    1024 |
+ *   |          |                  |    1280 |
+ *   |          |                  |     ... |
+ *   |          |                  |    3328 |
+ *   |          |                  |    3584 |
+ *   |          |                  |    3840 |
+ *   |=======================================|
+ *   | Large                       |    4 kB |
+ *   |                             |    8 kB |
+ *   |                             |   12 kB |
+ *   |                             |     ... |
+ *   |                             | 1012 kB |
+ *   |                             | 1016 kB |
+ *   |                             | 1020 kB |
+ *   |=======================================|
+ *   | Huge                        |    1 MB |
+ *   |                             |    2 MB |
+ *   |                             |    3 MB |
+ *   |                             |     ... |
+ *   |=======================================|
+ *
+ * A different mechanism is used for each category:
+ *
+ *   Small : Each size class is segregated into its own set of runs.  Each run
+ *           maintains a bitmap of which regions are free/allocated.
+ *
+ *   Large : Each allocation is backed by a dedicated run.  Metadata are stored
+ *           in the associated arena chunk header maps.
+ *
+ *   Huge : Each allocation is backed by a dedicated contiguous set of chunks.
+ *          Metadata are stored in a separate red-black tree.
+ *
+ *******************************************************************************
+ */
+
+/*
+ * MALLOC_PRODUCTION disables assertions and statistics gathering.  It also
+ * defaults the A and J runtime options to off.  These settings are appropriate
+ * for production systems.
+ */
+/* #define	MALLOC_PRODUCTION */
+
+#ifndef MALLOC_PRODUCTION
+   /*
+    * MALLOC_DEBUG enables assertions and other sanity checks, and disables
+    * inline functions.
+    */
+#  define MALLOC_DEBUG
+
+   /* MALLOC_STATS enables statistics calculation. */
+#  define MALLOC_STATS
+#endif
+
+/*
+ * MALLOC_TINY enables support for tiny objects, which are smaller than one
+ * quantum.
+ */
+#define	MALLOC_TINY
+
+/*
+ * MALLOC_MAG enables a magazine-based thread-specific caching layer for small
+ * objects.  This makes it possible to allocate/deallocate objects without any
+ * locking when the cache is in the steady state.
+ */
+#define	MALLOC_MAG
+
+/*
+ * MALLOC_BALANCE enables monitoring of arena lock contention and dynamically
+ * re-balances arena load if exponentially averaged contention exceeds a
+ * certain threshold.
+ */
+#define	MALLOC_BALANCE
+
+/*
+ * MALLOC_DSS enables use of sbrk(2) to allocate chunks from the data storage
+ * segment (DSS).  In an ideal world, this functionality would be completely
+ * unnecessary, but we are burdened by history and the lack of resource limits
+ * for anonymous mapped memory.
+ */
+#define	MALLOC_DSS
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/lib/libc/stdlib/malloc.c 182225 2008-08-27 02:00:53Z jasone $");
+
+#include "libc_private.h"
+#ifdef MALLOC_DEBUG
+#  define _LOCK_DEBUG
+#endif
+#include "spinlock.h"
+#include "namespace.h"
+#include <sys/mman.h>
+#include <sys/param.h>
+#include <sys/stddef.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#include <sys/uio.h>
+#include <sys/ktrace.h> /* Must come after several other sys/ includes. */
+
+#include <machine/cpufunc.h>
+#include <machine/vmparam.h>
+
+#include <errno.h>
+#include <limits.h>
+#include <pthread.h>
+#include <sched.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include <unistd.h>
+
+#include "un-namespace.h"
+
+#ifdef MALLOC_DEBUG
+#  ifdef NDEBUG
+#    undef NDEBUG
+#  endif
+#else
+#  ifndef NDEBUG
+#    define NDEBUG
+#  endif
+#endif
+#include <assert.h>
+
+#include "rb.h"
+
+#ifdef MALLOC_DEBUG
+   /* Disable inlining to make debugging easier. */
+#  define inline
+#endif
+
+/* Size of stack-allocated buffer passed to strerror_r(). */
+#define	STRERROR_BUF		64
+
+/*
+ * The const_size2bin table is sized according to PAGESIZE_2POW, but for
+ * correctness reasons, we never assume that
+ * (pagesize == (1U << * PAGESIZE_2POW)).
+ *
+ * Minimum alignment of allocations is 2^QUANTUM_2POW bytes.
+ */
+#ifdef __i386__
+#  define PAGESIZE_2POW		12
+#  define QUANTUM_2POW		4
+#  define SIZEOF_PTR_2POW	2
+#  define CPU_SPINWAIT		__asm__ volatile("pause")
+#endif
+#ifdef __ia64__
+#  define PAGESIZE_2POW		12
+#  define QUANTUM_2POW		4
+#  define SIZEOF_PTR_2POW	3
+#endif
+#ifdef __alpha__
+#  define PAGESIZE_2POW		13
+#  define QUANTUM_2POW		4
+#  define SIZEOF_PTR_2POW	3
+#  define NO_TLS
+#endif
+#ifdef __sparc64__
+#  define PAGESIZE_2POW		13
+#  define QUANTUM_2POW		4
+#  define SIZEOF_PTR_2POW	3
+#  define NO_TLS
+#endif
+#ifdef __amd64__
+#  define PAGESIZE_2POW		12
+#  define QUANTUM_2POW		4
+#  define SIZEOF_PTR_2POW	3
+#  define CPU_SPINWAIT		__asm__ volatile("pause")
+#endif
+#ifdef __arm__
+#  define PAGESIZE_2POW		12
+#  define QUANTUM_2POW		3
+#  define SIZEOF_PTR_2POW	2
+#  define NO_TLS
+#endif
+#ifdef __mips__
+#  define PAGESIZE_2POW		12
+#  define QUANTUM_2POW		3
+#  define SIZEOF_PTR_2POW	2
+#  define NO_TLS
+#endif
+#ifdef __powerpc__
+#  define PAGESIZE_2POW		12
+#  define QUANTUM_2POW		4
+#  define SIZEOF_PTR_2POW	2
+#endif
+
+#define	QUANTUM			((size_t)(1U << QUANTUM_2POW))
+#define	QUANTUM_MASK		(QUANTUM - 1)
+
+#define	SIZEOF_PTR		(1U << SIZEOF_PTR_2POW)
+
+/* sizeof(int) == (1U << SIZEOF_INT_2POW). */
+#ifndef SIZEOF_INT_2POW
+#  define SIZEOF_INT_2POW	2
+#endif
+
+/* We can't use TLS in non-PIC programs, since TLS relies on loader magic. */
+#if (!defined(PIC) && !defined(NO_TLS))
+#  define NO_TLS
+#endif
+
+#ifdef NO_TLS
+   /* MALLOC_MAG requires TLS. */
+#  ifdef MALLOC_MAG
+#    undef MALLOC_MAG
+#  endif
+   /* MALLOC_BALANCE requires TLS. */
+#  ifdef MALLOC_BALANCE
+#    undef MALLOC_BALANCE
+#  endif
+#endif
+
+/*
+ * Size and alignment of memory chunks that are allocated by the OS's virtual
+ * memory system.
+ */
+#define	CHUNK_2POW_DEFAULT	20
+
+/* Maximum number of dirty pages per arena. */
+#define	DIRTY_MAX_DEFAULT	(1U << 9)
+
+/*
+ * Maximum size of L1 cache line.  This is used to avoid cache line aliasing.
+ * In addition, this controls the spacing of cacheline-spaced size classes.
+ */
+#define	CACHELINE_2POW		6
+#define	CACHELINE		((size_t)(1U << CACHELINE_2POW))
+#define	CACHELINE_MASK		(CACHELINE - 1)
+
+/*
+ * Subpages are an artificially designated partitioning of pages.  Their only
+ * purpose is to support subpage-spaced size classes.
+ *
+ * There must be at least 4 subpages per page, due to the way size classes are
+ * handled.
+ */
+#define	SUBPAGE_2POW		8
+#define	SUBPAGE			((size_t)(1U << SUBPAGE_2POW))
+#define	SUBPAGE_MASK		(SUBPAGE - 1)
+
+#ifdef MALLOC_TINY
+   /* Smallest size class to support. */
+#  define TINY_MIN_2POW		1
+#endif
+
+/*
+ * Maximum size class that is a multiple of the quantum, but not (necessarily)
+ * a power of 2.  Above this size, allocations are rounded up to the nearest
+ * power of 2.
+ */
+#define	QSPACE_MAX_2POW_DEFAULT	7
+
+/*
+ * Maximum size class that is a multiple of the cacheline, but not (necessarily)
+ * a power of 2.  Above this size, allocations are rounded up to the nearest
+ * power of 2.
+ */
+#define	CSPACE_MAX_2POW_DEFAULT	9
+
+/*
+ * RUN_MAX_OVRHD indicates maximum desired run header overhead.  Runs are sized
+ * as small as possible such that this setting is still honored, without
+ * violating other constraints.  The goal is to make runs as small as possible
+ * without exceeding a per run external fragmentation threshold.
+ *
+ * We use binary fixed point math for overhead computations, where the binary
+ * point is implicitly RUN_BFP bits to the left.
+ *
+ * Note that it is possible to set RUN_MAX_OVRHD low enough that it cannot be
+ * honored for some/all object sizes, since there is one bit of header overhead
+ * per object (plus a constant).  This constraint is relaxed (ignored) for runs
+ * that are so small that the per-region overhead is greater than:
+ *
+ *   (RUN_MAX_OVRHD / (reg_size << (3+RUN_BFP))
+ */
+#define	RUN_BFP			12
+/*                                    \/   Implicit binary fixed point. */
+#define	RUN_MAX_OVRHD		0x0000003dU
+#define	RUN_MAX_OVRHD_RELAX	0x00001800U
+
+/* Put a cap on small object run size.  This overrides RUN_MAX_OVRHD. */
+#define	RUN_MAX_SMALL	(12 * pagesize)
+
+/*
+ * Hyper-threaded CPUs may need a special instruction inside spin loops in
+ * order to yield to another virtual CPU.  If no such instruction is defined
+ * above, make CPU_SPINWAIT a no-op.
+ */
+#ifndef CPU_SPINWAIT
+#  define CPU_SPINWAIT
+#endif
+
+/*
+ * Adaptive spinning must eventually switch to blocking, in order to avoid the
+ * potential for priority inversion deadlock.  Backing off past a certain point
+ * can actually waste time.
+ */
+#define	SPIN_LIMIT_2POW		11
+
+/*
+ * Conversion from spinning to blocking is expensive; we use (1U <<
+ * BLOCK_COST_2POW) to estimate how many more times costly blocking is than
+ * worst-case spinning.
+ */
+#define	BLOCK_COST_2POW		4
+
+#ifdef MALLOC_MAG
+   /*
+    * Default magazine size, in bytes.  max_rounds is calculated to make
+    * optimal use of the space, leaving just enough room for the magazine
+    * header.
+    */
+#  define MAG_SIZE_2POW_DEFAULT	9
+#endif
+
+#ifdef MALLOC_BALANCE
+   /*
+    * We use an exponential moving average to track recent lock contention,
+    * where the size of the history window is N, and alpha=2/(N+1).
+    *
+    * Due to integer math rounding, very small values here can cause
+    * substantial degradation in accuracy, thus making the moving average decay
+    * faster than it would with precise calculation.
+    */
+#  define BALANCE_ALPHA_INV_2POW	9
+
+   /*
+    * Threshold value for the exponential moving contention average at which to
+    * re-assign a thread.
+    */
+#  define BALANCE_THRESHOLD_DEFAULT	(1U << (SPIN_LIMIT_2POW-4))
+#endif
+
+/******************************************************************************/
+
+/*
+ * Mutexes based on spinlocks.  We can't use normal pthread spinlocks in all
+ * places, because they require malloc()ed memory, which causes bootstrapping
+ * issues in some cases.
+ */
+typedef struct {
+	spinlock_t	lock;
+} malloc_mutex_t;
+
+/* Set to true once the allocator has been initialized. */
+static bool malloc_initialized = false;
+
+/* Used to avoid initialization races. */
+static malloc_mutex_t init_lock = {_SPINLOCK_INITIALIZER};
+
+/******************************************************************************/
+/*
+ * Statistics data structures.
+ */
+
+#ifdef MALLOC_STATS
+
+typedef struct malloc_bin_stats_s malloc_bin_stats_t;
+struct malloc_bin_stats_s {
+	/*
+	 * Number of allocation requests that corresponded to the size of this
+	 * bin.
+	 */
+	uint64_t	nrequests;
+
+#ifdef MALLOC_MAG
+	/* Number of magazine reloads from this bin. */
+	uint64_t	nmags;
+#endif
+
+	/* Total number of runs created for this bin's size class. */
+	uint64_t	nruns;
+
+	/*
+	 * Total number of runs reused by extracting them from the runs tree for
+	 * this bin's size class.
+	 */
+	uint64_t	reruns;
+
+	/* High-water mark for this bin. */
+	unsigned long	highruns;
+
+	/* Current number of runs in this bin. */
+	unsigned long	curruns;
+};
+
+typedef struct arena_stats_s arena_stats_t;
+struct arena_stats_s {
+	/* Number of bytes currently mapped. */
+	size_t		mapped;
+
+	/*
+	 * Total number of purge sweeps, total number of madvise calls made,
+	 * and total pages purged in order to keep dirty unused memory under
+	 * control.
+	 */
+	uint64_t	npurge;
+	uint64_t	nmadvise;
+	uint64_t	purged;
+
+	/* Per-size-category statistics. */
+	size_t		allocated_small;
+	uint64_t	nmalloc_small;
+	uint64_t	ndalloc_small;
+
+	size_t		allocated_large;
+	uint64_t	nmalloc_large;
+	uint64_t	ndalloc_large;
+
+#ifdef MALLOC_BALANCE
+	/* Number of times this arena reassigned a thread due to contention. */
+	uint64_t	nbalance;
+#endif
+};
+
+typedef struct chunk_stats_s chunk_stats_t;
+struct chunk_stats_s {
+	/* Number of chunks that were allocated. */
+	uint64_t	nchunks;
+
+	/* High-water mark for number of chunks allocated. */
+	unsigned long	highchunks;
+
+	/*
+	 * Current number of chunks allocated.  This value isn't maintained for
+	 * any other purpose, so keep track of it in order to be able to set
+	 * highchunks.
+	 */
+	unsigned long	curchunks;
+};
+
+#endif /* #ifdef MALLOC_STATS */
+
+/******************************************************************************/
+/*
+ * Extent data structures.
+ */
+
+/* Tree of extents. */
+typedef struct extent_node_s extent_node_t;
+struct extent_node_s {
+#ifdef MALLOC_DSS
+	/* Linkage for the size/address-ordered tree. */
+	rb_node(extent_node_t) link_szad;
+#endif
+
+	/* Linkage for the address-ordered tree. */
+	rb_node(extent_node_t) link_ad;
+
+	/* Pointer to the extent that this tree node is responsible for. */
+	void	*addr;
+
+	/* Total region size. */
+	size_t	size;
+};
+typedef rb_tree(extent_node_t) extent_tree_t;
+
+/******************************************************************************/
+/*
+ * Arena data structures.
+ */
+
+typedef struct arena_s arena_t;
+typedef struct arena_bin_s arena_bin_t;
+
+/* Each element of the chunk map corresponds to one page within the chunk. */
+typedef struct arena_chunk_map_s arena_chunk_map_t;
+struct arena_chunk_map_s {
+	/*
+	 * Linkage for run trees.  There are two disjoint uses:
+	 *
+	 * 1) arena_t's runs_avail tree.
+	 * 2) arena_run_t conceptually uses this linkage for in-use non-full
+	 *    runs, rather than directly embedding linkage.
+	 */
+	rb_node(arena_chunk_map_t)	link;
+
+	/*
+	 * Run address (or size) and various flags are stored together.  The bit
+	 * layout looks like (assuming 32-bit system):
+	 *
+	 *   ???????? ???????? ????---- ---kdzla
+	 *
+	 * ? : Unallocated: Run address for first/last pages, unset for internal
+	 *                  pages.
+	 *     Small: Run address.
+	 *     Large: Run size for first page, unset for trailing pages.
+	 * - : Unused.
+	 * k : key?
+	 * d : dirty?
+	 * z : zeroed?
+	 * l : large?
+	 * a : allocated?
+	 *
+	 * Following are example bit patterns for the three types of runs.
+	 *
+	 * r : run address
+	 * s : run size
+	 * x : don't care
+	 * - : 0
+	 * [dzla] : bit set
+	 *
+	 *   Unallocated:
+	 *     ssssssss ssssssss ssss---- --------
+	 *     xxxxxxxx xxxxxxxx xxxx---- ----d---
+	 *     ssssssss ssssssss ssss---- -----z--
+	 *
+	 *   Small:
+	 *     rrrrrrrr rrrrrrrr rrrr---- -------a
+	 *     rrrrrrrr rrrrrrrr rrrr---- -------a
+	 *     rrrrrrrr rrrrrrrr rrrr---- -------a
+	 *
+	 *   Large:
+	 *     ssssssss ssssssss ssss---- ------la
+	 *     -------- -------- -------- ------la
+	 *     -------- -------- -------- ------la
+	 */
+	size_t				bits;
+#define	CHUNK_MAP_KEY		((size_t)0x10U)
+#define	CHUNK_MAP_DIRTY		((size_t)0x08U)
+#define	CHUNK_MAP_ZEROED	((size_t)0x04U)
+#define	CHUNK_MAP_LARGE		((size_t)0x02U)
+#define	CHUNK_MAP_ALLOCATED	((size_t)0x01U)
+};
+typedef rb_tree(arena_chunk_map_t) arena_avail_tree_t;
+typedef rb_tree(arena_chunk_map_t) arena_run_tree_t;
+
+/* Arena chunk header. */
+typedef struct arena_chunk_s arena_chunk_t;
+struct arena_chunk_s {
+	/* Arena that owns the chunk. */
+	arena_t		*arena;
+
+	/* Linkage for the arena's chunks_dirty tree. */
+	rb_node(arena_chunk_t) link_dirty;
+
+	/* Number of dirty pages. */
+	size_t		ndirty;
+
+	/* Map of pages within chunk that keeps track of free/large/small. */
+	arena_chunk_map_t map[1]; /* Dynamically sized. */
+};
+typedef rb_tree(arena_chunk_t) arena_chunk_tree_t;
+
+typedef struct arena_run_s arena_run_t;
+struct arena_run_s {
+#ifdef MALLOC_DEBUG
+	uint32_t	magic;
+#  define ARENA_RUN_MAGIC 0x384adf93
+#endif
+
+	/* Bin this run is associated with. */
+	arena_bin_t	*bin;
+
+	/* Index of first element that might have a free region. */
+	unsigned	regs_minelm;
+
+	/* Number of free regions in run. */
+	unsigned	nfree;
+
+	/* Bitmask of in-use regions (0: in use, 1: free). */
+	unsigned	regs_mask[1]; /* Dynamically sized. */
+};
+
+struct arena_bin_s {
+	/*
+	 * Current run being used to service allocations of this bin's size
+	 * class.
+	 */
+	arena_run_t	*runcur;
+
+	/*
+	 * Tree of non-full runs.  This tree is used when looking for an
+	 * existing run when runcur is no longer usable.  We choose the
+	 * non-full run that is lowest in memory; this policy tends to keep
+	 * objects packed well, and it can also help reduce the number of
+	 * almost-empty chunks.
+	 */
+	arena_run_tree_t runs;
+
+	/* Size of regions in a run for this bin's size class. */
+	size_t		reg_size;
+
+	/* Total size of a run for this bin's size class. */
+	size_t		run_size;
+
+	/* Total number of regions in a run for this bin's size class. */
+	uint32_t	nregs;
+
+	/* Number of elements in a run's regs_mask for this bin's size class. */
+	uint32_t	regs_mask_nelms;
+
+	/* Offset of first region in a run for this bin's size class. */
+	uint32_t	reg0_offset;
+
+#ifdef MALLOC_STATS
+	/* Bin statistics. */
+	malloc_bin_stats_t stats;
+#endif
+};
+
+struct arena_s {
+#ifdef MALLOC_DEBUG
+	uint32_t		magic;
+#  define ARENA_MAGIC 0x947d3d24
+#endif
+
+	/* All operations on this arena require that lock be locked. */
+	pthread_mutex_t		lock;
+
+#ifdef MALLOC_STATS
+	arena_stats_t		stats;
+#endif
+
+	/* Tree of dirty-page-containing chunks this arena manages. */
+	arena_chunk_tree_t	chunks_dirty;
+
+	/*
+	 * In order to avoid rapid chunk allocation/deallocation when an arena
+	 * oscillates right on the cusp of needing a new chunk, cache the most
+	 * recently freed chunk.  The spare is left in the arena's chunk trees
+	 * until it is deleted.
+	 *
+	 * There is one spare chunk per arena, rather than one spare total, in
+	 * order to avoid interactions between multiple threads that could make
+	 * a single spare inadequate.
+	 */
+	arena_chunk_t		*spare;
+
+	/*
+	 * Current count of pages within unused runs that are potentially
+	 * dirty, and for which madvise(... MADV_FREE) has not been called.  By
+	 * tracking this, we can institute a limit on how much dirty unused
+	 * memory is mapped for each arena.
+	 */
+	size_t			ndirty;
+
+	/*
+	 * Size/address-ordered tree of this arena's available runs.  This tree
+	 * is used for first-best-fit run allocation.
+	 */
+	arena_avail_tree_t	runs_avail;
+
+#ifdef MALLOC_BALANCE
+	/*
+	 * The arena load balancing machinery needs to keep track of how much
+	 * lock contention there is.  This value is exponentially averaged.
+	 */
+	uint32_t		contention;
+#endif
+
+	/*
+	 * bins is used to store rings of free regions of the following sizes,
+	 * assuming a 16-byte quantum, 4kB pagesize, and default MALLOC_OPTIONS.
+	 *
+	 *   bins[i] | size |
+	 *   --------+------+
+	 *        0  |    2 |
+	 *        1  |    4 |
+	 *        2  |    8 |
+	 *   --------+------+
+	 *        3  |   16 |
+	 *        4  |   32 |
+	 *        5  |   48 |
+	 *        6  |   64 |
+	 *           :      :
+	 *           :      :
+	 *       33  |  496 |
+	 *       34  |  512 |
+	 *   --------+------+
+	 *       35  | 1024 |
+	 *       36  | 2048 |
+	 *   --------+------+
+	 */
+	arena_bin_t		bins[1]; /* Dynamically sized. */
+};
+
+/******************************************************************************/
+/*
+ * Magazine data structures.
+ */
+
+#ifdef MALLOC_MAG
+typedef struct mag_s mag_t;
+struct mag_s {
+	size_t		binind; /* Index of associated bin. */
+	size_t		nrounds;
+	void		*rounds[1]; /* Dynamically sized. */
+};
+
+/*
+ * Magazines are lazily allocated, but once created, they remain until the
+ * associated mag_rack is destroyed.
+ */
+typedef struct bin_mags_s bin_mags_t;
+struct bin_mags_s {
+	mag_t	*curmag;
+	mag_t	*sparemag;
+};
+
+typedef struct mag_rack_s mag_rack_t;
+struct mag_rack_s {
+	bin_mags_t	bin_mags[1]; /* Dynamically sized. */
+};
+#endif
+
+/******************************************************************************/
+/*
+ * Data.
+ */
+
+/* Number of CPUs. */
+static unsigned		ncpus;
+
+/* VM page size. */
+static size_t		pagesize;
+static size_t		pagesize_mask;
+static size_t		pagesize_2pow;
+
+/* Various bin-related settings. */
+#ifdef MALLOC_TINY		/* Number of (2^n)-spaced tiny bins. */
+#  define		ntbins	((unsigned)(QUANTUM_2POW - TINY_MIN_2POW))
+#else
+#  define		ntbins	0
+#endif
+static unsigned		nqbins; /* Number of quantum-spaced bins. */
+static unsigned		ncbins; /* Number of cacheline-spaced bins. */
+static unsigned		nsbins; /* Number of subpage-spaced bins. */
+static unsigned		nbins;
+#ifdef MALLOC_TINY
+#  define		tspace_max	((size_t)(QUANTUM >> 1))
+#endif
+#define			qspace_min	QUANTUM
+static size_t		qspace_max;
+static size_t		cspace_min;
+static size_t		cspace_max;
+static size_t		sspace_min;
+static size_t		sspace_max;
+#define			bin_maxclass	sspace_max
+
+static uint8_t const	*size2bin;
+/*
+ * const_size2bin is a static constant lookup table that in the common case can
+ * be used as-is for size2bin.  For dynamically linked programs, this avoids
+ * a page of memory overhead per process.
+ */
+#define	S2B_1(i)	i,
+#define	S2B_2(i)	S2B_1(i) S2B_1(i)
+#define	S2B_4(i)	S2B_2(i) S2B_2(i)
+#define	S2B_8(i)	S2B_4(i) S2B_4(i)
+#define	S2B_16(i)	S2B_8(i) S2B_8(i)
+#define	S2B_32(i)	S2B_16(i) S2B_16(i)
+#define	S2B_64(i)	S2B_32(i) S2B_32(i)
+#define	S2B_128(i)	S2B_64(i) S2B_64(i)
+#define	S2B_256(i)	S2B_128(i) S2B_128(i)
+static const uint8_t	const_size2bin[(1U << PAGESIZE_2POW) - 255] = {
+	S2B_1(0xffU)		/*    0 */
+#if (QUANTUM_2POW == 4)
+/* 64-bit system ************************/
+#  ifdef MALLOC_TINY
+	S2B_2(0)		/*    2 */
+	S2B_2(1)		/*    4 */
+	S2B_4(2)		/*    8 */
+	S2B_8(3)		/*   16 */
+#    define S2B_QMIN 3
+#  else
+	S2B_16(0)		/*   16 */
+#    define S2B_QMIN 0
+#  endif
+	S2B_16(S2B_QMIN + 1)	/*   32 */
+	S2B_16(S2B_QMIN + 2)	/*   48 */
+	S2B_16(S2B_QMIN + 3)	/*   64 */
+	S2B_16(S2B_QMIN + 4)	/*   80 */
+	S2B_16(S2B_QMIN + 5)	/*   96 */
+	S2B_16(S2B_QMIN + 6)	/*  112 */
+	S2B_16(S2B_QMIN + 7)	/*  128 */
+#  define S2B_CMIN (S2B_QMIN + 8)
+#else
+/* 32-bit system ************************/
+#  ifdef MALLOC_TINY
+	S2B_2(0)		/*    2 */
+	S2B_2(1)		/*    4 */
+	S2B_4(2)		/*    8 */
+#    define S2B_QMIN 2
+#  else
+	S2B_8(0)		/*    8 */
+#    define S2B_QMIN 0
+#  endif
+	S2B_8(S2B_QMIN + 1)	/*   16 */
+	S2B_8(S2B_QMIN + 2)	/*   24 */
+	S2B_8(S2B_QMIN + 3)	/*   32 */
+	S2B_8(S2B_QMIN + 4)	/*   40 */
+	S2B_8(S2B_QMIN + 5)	/*   48 */
+	S2B_8(S2B_QMIN + 6)	/*   56 */
+	S2B_8(S2B_QMIN + 7)	/*   64 */
+	S2B_8(S2B_QMIN + 8)	/*   72 */
+	S2B_8(S2B_QMIN + 9)	/*   80 */
+	S2B_8(S2B_QMIN + 10)	/*   88 */
+	S2B_8(S2B_QMIN + 11)	/*   96 */
+	S2B_8(S2B_QMIN + 12)	/*  104 */
+	S2B_8(S2B_QMIN + 13)	/*  112 */
+	S2B_8(S2B_QMIN + 14)	/*  120 */
+	S2B_8(S2B_QMIN + 15)	/*  128 */
+#  define S2B_CMIN (S2B_QMIN + 16)
+#endif
+/****************************************/
+	S2B_64(S2B_CMIN + 0)	/*  192 */
+	S2B_64(S2B_CMIN + 1)	/*  256 */
+	S2B_64(S2B_CMIN + 2)	/*  320 */
+	S2B_64(S2B_CMIN + 3)	/*  384 */
+	S2B_64(S2B_CMIN + 4)	/*  448 */
+	S2B_64(S2B_CMIN + 5)	/*  512 */
+#  define S2B_SMIN (S2B_CMIN + 6)
+	S2B_256(S2B_SMIN + 0)	/*  768 */
+	S2B_256(S2B_SMIN + 1)	/* 1024 */
+	S2B_256(S2B_SMIN + 2)	/* 1280 */
+	S2B_256(S2B_SMIN + 3)	/* 1536 */
+	S2B_256(S2B_SMIN + 4)	/* 1792 */
+	S2B_256(S2B_SMIN + 5)	/* 2048 */
+	S2B_256(S2B_SMIN + 6)	/* 2304 */
+	S2B_256(S2B_SMIN + 7)	/* 2560 */
+	S2B_256(S2B_SMIN + 8)	/* 2816 */
+	S2B_256(S2B_SMIN + 9)	/* 3072 */
+	S2B_256(S2B_SMIN + 10)	/* 3328 */
+	S2B_256(S2B_SMIN + 11)	/* 3584 */
+	S2B_256(S2B_SMIN + 12)	/* 3840 */
+#if (PAGESIZE_2POW == 13)
+	S2B_256(S2B_SMIN + 13)	/* 4096 */
+	S2B_256(S2B_SMIN + 14)	/* 4352 */
+	S2B_256(S2B_SMIN + 15)	/* 4608 */
+	S2B_256(S2B_SMIN + 16)	/* 4864 */
+	S2B_256(S2B_SMIN + 17)	/* 5120 */
+	S2B_256(S2B_SMIN + 18)	/* 5376 */
+	S2B_256(S2B_SMIN + 19)	/* 5632 */
+	S2B_256(S2B_SMIN + 20)	/* 5888 */
+	S2B_256(S2B_SMIN + 21)	/* 6144 */
+	S2B_256(S2B_SMIN + 22)	/* 6400 */
+	S2B_256(S2B_SMIN + 23)	/* 6656 */
+	S2B_256(S2B_SMIN + 24)	/* 6912 */
+	S2B_256(S2B_SMIN + 25)	/* 7168 */
+	S2B_256(S2B_SMIN + 26)	/* 7424 */
+	S2B_256(S2B_SMIN + 27)	/* 7680 */
+	S2B_256(S2B_SMIN + 28)	/* 7936 */
+#endif
+};
+#undef S2B_1
+#undef S2B_2
+#undef S2B_4
+#undef S2B_8
+#undef S2B_16
+#undef S2B_32
+#undef S2B_64
+#undef S2B_128
+#undef S2B_256
+#undef S2B_QMIN
+#undef S2B_CMIN
+#undef S2B_SMIN
+
+#ifdef MALLOC_MAG
+static size_t		max_rounds;
+#endif
+
+/* Various chunk-related settings. */
+static size_t		chunksize;
+static size_t		chunksize_mask; /* (chunksize - 1). */
+static size_t		chunk_npages;
+static size_t		arena_chunk_header_npages;
+static size_t		arena_maxclass; /* Max size class for arenas. */
+
+/********/
+/*
+ * Chunks.
+ */
+
+/* Protects chunk-related data structures. */
+static malloc_mutex_t	huge_mtx;
+
+/* Tree of chunks that are stand-alone huge allocations. */
+static extent_tree_t	huge;
+
+#ifdef MALLOC_DSS
+/*
+ * Protects sbrk() calls.  This avoids malloc races among threads, though it
+ * does not protect against races with threads that call sbrk() directly.
+ */
+static malloc_mutex_t	dss_mtx;
+/* Base address of the DSS. */
+static void		*dss_base;
+/* Current end of the DSS, or ((void *)-1) if the DSS is exhausted. */
+static void		*dss_prev;
+/* Current upper limit on DSS addresses. */
+static void		*dss_max;
+
+/*
+ * Trees of chunks that were previously allocated (trees differ only in node
+ * ordering).  These are used when allocating chunks, in an attempt to re-use
+ * address space.  Depending on function, different tree orderings are needed,
+ * which is why there are two trees with the same contents.
+ */
+static extent_tree_t	dss_chunks_szad;
+static extent_tree_t	dss_chunks_ad;
+#endif
+
+#ifdef MALLOC_STATS
+/* Huge allocation statistics. */
+static uint64_t		huge_nmalloc;
+static uint64_t		huge_ndalloc;
+static size_t		huge_allocated;
+#endif
+
+/****************************/
+/*
+ * base (internal allocation).
+ */
+
+/*
+ * Current pages that are being used for internal memory allocations.  These
+ * pages are carved up in cacheline-size quanta, so that there is no chance of
+ * false cache line sharing.
+ */
+static void		*base_pages;
+static void		*base_next_addr;
+static void		*base_past_addr; /* Addr immediately past base_pages. */
+static extent_node_t	*base_nodes;
+static malloc_mutex_t	base_mtx;
+#ifdef MALLOC_STATS
+static size_t		base_mapped;
+#endif
+
+/********/
+/*
+ * Arenas.
+ */
+
+/*
+ * Arenas that are used to service external requests.  Not all elements of the
+ * arenas array are necessarily used; arenas are created lazily as needed.
+ */
+static arena_t		**arenas;
+static unsigned		narenas;
+#ifndef NO_TLS
+#  ifdef MALLOC_BALANCE
+static unsigned		narenas_2pow;
+#  else
+static unsigned		next_arena;
+#  endif
+#endif
+static pthread_mutex_t	arenas_lock; /* Protects arenas initialization. */
+
+#ifndef NO_TLS
+/*
+ * Map of pthread_self() --> arenas[???], used for selecting an arena to use
+ * for allocations.
+ */
+static __thread arena_t	*arenas_map;
+#endif
+
+#ifdef MALLOC_MAG
+/*
+ * Map of thread-specific magazine racks, used for thread-specific object
+ * caching.
+ */
+static __thread mag_rack_t	*mag_rack;
+#endif
+
+#ifdef MALLOC_STATS
+/* Chunk statistics. */
+static chunk_stats_t	stats_chunks;
+#endif
+
+/*******************************/
+/*
+ * Runtime configuration options.
+ */
+const char	*_malloc_options;
+
+#ifndef MALLOC_PRODUCTION
+static bool	opt_abort = true;
+static bool	opt_junk = true;
+#else
+static bool	opt_abort = false;
+static bool	opt_junk = false;
+#endif
+#ifdef MALLOC_DSS
+static bool	opt_dss = true;
+static bool	opt_mmap = true;
+#endif
+#ifdef MALLOC_MAG
+static bool	opt_mag = true;
+static size_t	opt_mag_size_2pow = MAG_SIZE_2POW_DEFAULT;
+#endif
+static size_t	opt_dirty_max = DIRTY_MAX_DEFAULT;
+#ifdef MALLOC_BALANCE
+static uint64_t	opt_balance_threshold = BALANCE_THRESHOLD_DEFAULT;
+#endif
+static bool	opt_print_stats = false;
+static size_t	opt_qspace_max_2pow = QSPACE_MAX_2POW_DEFAULT;
+static size_t	opt_cspace_max_2pow = CSPACE_MAX_2POW_DEFAULT;
+static size_t	opt_chunk_2pow = CHUNK_2POW_DEFAULT;
+static bool	opt_utrace = false;
+static bool	opt_sysv = false;
+static bool	opt_xmalloc = false;
+static bool	opt_zero = false;
+static int	opt_narenas_lshift = 0;
+
+typedef struct {
+	void	*p;
+	size_t	s;
+	void	*r;
+} malloc_utrace_t;
+
+#define	UTRACE(a, b, c)							\
+	if (opt_utrace) {						\
+		malloc_utrace_t ut;					\
+		ut.p = (a);						\
+		ut.s = (b);						\
+		ut.r = (c);						\
+		utrace(&ut, sizeof(ut));				\
+	}
+
+/******************************************************************************/
+/*
+ * Begin function prototypes for non-inline static functions.
+ */
+
+static void	malloc_mutex_init(malloc_mutex_t *mutex);
+static bool	malloc_spin_init(pthread_mutex_t *lock);
+static void	wrtmessage(const char *p1, const char *p2, const char *p3,
+		const char *p4);
+#ifdef MALLOC_STATS
+static void	malloc_printf(const char *format, ...);
+#endif
+static char	*umax2s(uintmax_t x, char *s);
+#ifdef MALLOC_DSS
+static bool	base_pages_alloc_dss(size_t minsize);
+#endif
+static bool	base_pages_alloc_mmap(size_t minsize);
+static bool	base_pages_alloc(size_t minsize);
+static void	*base_alloc(size_t size);
+static void	*base_calloc(size_t number, size_t size);
+static extent_node_t *base_node_alloc(void);
+static void	base_node_dealloc(extent_node_t *node);
+#ifdef MALLOC_STATS
+static void	stats_print(arena_t *arena);
+#endif
+static void	*pages_map(void *addr, size_t size);
+static void	pages_unmap(void *addr, size_t size);
+#ifdef MALLOC_DSS
+static void	*chunk_alloc_dss(size_t size);
+static void	*chunk_recycle_dss(size_t size, bool zero);
+#endif
+static void	*chunk_alloc_mmap(size_t size);
+static void	*chunk_alloc(size_t size, bool zero);
+#ifdef MALLOC_DSS
+static extent_node_t *chunk_dealloc_dss_record(void *chunk, size_t size);
+static bool	chunk_dealloc_dss(void *chunk, size_t size);
+#endif
+static void	chunk_dealloc_mmap(void *chunk, size_t size);
+static void	chunk_dealloc(void *chunk, size_t size);
+#ifndef NO_TLS
+static arena_t	*choose_arena_hard(void);
+#endif
+static void	arena_run_split(arena_t *arena, arena_run_t *run, size_t size,
+    bool large, bool zero);
+static arena_chunk_t *arena_chunk_alloc(arena_t *arena);
+static void	arena_chunk_dealloc(arena_t *arena, arena_chunk_t *chunk);
+static arena_run_t *arena_run_alloc(arena_t *arena, size_t size, bool large,
+    bool zero);
+static void	arena_purge(arena_t *arena);
+static void	arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty);
+static void	arena_run_trim_head(arena_t *arena, arena_chunk_t *chunk,
+    arena_run_t *run, size_t oldsize, size_t newsize);
+static void	arena_run_trim_tail(arena_t *arena, arena_chunk_t *chunk,
+    arena_run_t *run, size_t oldsize, size_t newsize, bool dirty);
+static arena_run_t *arena_bin_nonfull_run_get(arena_t *arena, arena_bin_t *bin);
+static void	*arena_bin_malloc_hard(arena_t *arena, arena_bin_t *bin);
+static size_t	arena_bin_run_size_calc(arena_bin_t *bin, size_t min_run_size);
+#ifdef MALLOC_BALANCE
+static void	arena_lock_balance_hard(arena_t *arena);
+#endif
+#ifdef MALLOC_MAG
+static void	mag_load(mag_t *mag);
+#endif
+static void	*arena_malloc_large(arena_t *arena, size_t size, bool zero);
+static void	*arena_palloc(arena_t *arena, size_t alignment, size_t size,
+    size_t alloc_size);
+static size_t	arena_salloc(const void *ptr);
+#ifdef MALLOC_MAG
+static void	mag_unload(mag_t *mag);
+#endif
+static void	arena_dalloc_large(arena_t *arena, arena_chunk_t *chunk,
+    void *ptr);
+static void	arena_ralloc_large_shrink(arena_t *arena, arena_chunk_t *chunk,
+    void *ptr, size_t size, size_t oldsize);
+static bool	arena_ralloc_large_grow(arena_t *arena, arena_chunk_t *chunk,
+    void *ptr, size_t size, size_t oldsize);
+static bool	arena_ralloc_large(void *ptr, size_t size, size_t oldsize);
+static void	*arena_ralloc(void *ptr, size_t size, size_t oldsize);
+static bool	arena_new(arena_t *arena);
+static arena_t	*arenas_extend(unsigned ind);
+#ifdef MALLOC_MAG
+static mag_t	*mag_create(arena_t *arena, size_t binind);
+static void	mag_destroy(mag_t *mag);
+static mag_rack_t *mag_rack_create(arena_t *arena);
+static void	mag_rack_destroy(mag_rack_t *rack);
+#endif
+static void	*huge_malloc(size_t size, bool zero);
+static void	*huge_palloc(size_t alignment, size_t size);
+static void	*huge_ralloc(void *ptr, size_t size, size_t oldsize);
+static void	huge_dalloc(void *ptr);
+static void	malloc_print_stats(void);
+#ifdef MALLOC_DEBUG
+static void	size2bin_validate(void);
+#endif
+static bool	size2bin_init(void);
+static bool	size2bin_init_hard(void);
+static bool	malloc_init_hard(void);
+
+/*
+ * End function prototypes.
+ */
+/******************************************************************************/
+/*
+ * Begin mutex.  We can't use normal pthread mutexes in all places, because
+ * they require malloc()ed memory, which causes bootstrapping issues in some
+ * cases.
+ */
+
+static void
+malloc_mutex_init(malloc_mutex_t *mutex)
+{
+	static const spinlock_t lock = _SPINLOCK_INITIALIZER;
+
+	mutex->lock = lock;
+}
+
+static inline void
+malloc_mutex_lock(malloc_mutex_t *mutex)
+{
+
+	if (__isthreaded)
+		_SPINLOCK(&mutex->lock);
+}
+
+static inline void
+malloc_mutex_unlock(malloc_mutex_t *mutex)
+{
+
+	if (__isthreaded)
+		_SPINUNLOCK(&mutex->lock);
+}
+
+/*
+ * End mutex.
+ */
+/******************************************************************************/
+/*
+ * Begin spin lock.  Spin locks here are actually adaptive mutexes that block
+ * after a period of spinning, because unbounded spinning would allow for
+ * priority inversion.
+ */
+
+/*
+ * We use an unpublished interface to initialize pthread mutexes with an
+ * allocation callback, in order to avoid infinite recursion.
+ */
+int	_pthread_mutex_init_calloc_cb(pthread_mutex_t *mutex,
+    void *(calloc_cb)(size_t, size_t));
+
+__weak_reference(_pthread_mutex_init_calloc_cb_stub,
+    _pthread_mutex_init_calloc_cb);
+
+int
+_pthread_mutex_init_calloc_cb_stub(pthread_mutex_t *mutex,
+    void *(calloc_cb)(size_t, size_t))
+{
+
+	return (0);
+}
+
+static bool
+malloc_spin_init(pthread_mutex_t *lock)
+{
+
+	if (_pthread_mutex_init_calloc_cb(lock, base_calloc) != 0)
+		return (true);
+
+	return (false);
+}
+
+static inline unsigned
+malloc_spin_lock(pthread_mutex_t *lock)
+{
+	unsigned ret = 0;
+
+	if (__isthreaded) {
+		if (_pthread_mutex_trylock(lock) != 0) {
+			unsigned i;
+			volatile unsigned j;
+
+			/* Exponentially back off. */
+			for (i = 1; i <= SPIN_LIMIT_2POW; i++) {
+				for (j = 0; j < (1U << i); j++) {
+					ret++;
+					CPU_SPINWAIT;
+				}
+
+				if (_pthread_mutex_trylock(lock) == 0)
+					return (ret);
+			}
+
+			/*
+			 * Spinning failed.  Block until the lock becomes
+			 * available, in order to avoid indefinite priority
+			 * inversion.
+			 */
+			_pthread_mutex_lock(lock);
+			assert((ret << BLOCK_COST_2POW) != 0);
+			return (ret << BLOCK_COST_2POW);
+		}
+	}
+
+	return (ret);
+}
+
+static inline void
+malloc_spin_unlock(pthread_mutex_t *lock)
+{
+
+	if (__isthreaded)
+		_pthread_mutex_unlock(lock);
+}
+
+/*
+ * End spin lock.
+ */
+/******************************************************************************/
+/*
+ * Begin Utility functions/macros.
+ */
+
+/* Return the chunk address for allocation address a. */
+#define	CHUNK_ADDR2BASE(a)						\
+	((void *)((uintptr_t)(a) & ~chunksize_mask))
+
+/* Return the chunk offset of address a. */
+#define	CHUNK_ADDR2OFFSET(a)						\
+	((size_t)((uintptr_t)(a) & chunksize_mask))
+
+/* Return the smallest chunk multiple that is >= s. */
+#define	CHUNK_CEILING(s)						\
+	(((s) + chunksize_mask) & ~chunksize_mask)
+
+/* Return the smallest quantum multiple that is >= a. */
+#define	QUANTUM_CEILING(a)						\
+	(((a) + QUANTUM_MASK) & ~QUANTUM_MASK)
+
+/* Return the smallest cacheline multiple that is >= s. */
+#define	CACHELINE_CEILING(s)						\
+	(((s) + CACHELINE_MASK) & ~CACHELINE_MASK)
+
+/* Return the smallest subpage multiple that is >= s. */
+#define	SUBPAGE_CEILING(s)						\
+	(((s) + SUBPAGE_MASK) & ~SUBPAGE_MASK)
+
+/* Return the smallest pagesize multiple that is >= s. */
+#define	PAGE_CEILING(s)							\
+	(((s) + pagesize_mask) & ~pagesize_mask)
+
+#ifdef MALLOC_TINY
+/* Compute the smallest power of 2 that is >= x. */
+static inline size_t
+pow2_ceil(size_t x)
+{
+
+	x--;
+	x |= x >> 1;
+	x |= x >> 2;
+	x |= x >> 4;
+	x |= x >> 8;
+	x |= x >> 16;
+#if (SIZEOF_PTR == 8)
+	x |= x >> 32;
+#endif
+	x++;
+	return (x);
+}
+#endif
+
+#ifdef MALLOC_BALANCE
+/*
+ * Use a simple linear congruential pseudo-random number generator:
+ *
+ *   prn(y) = (a*x + c) % m
+ *
+ * where the following constants ensure maximal period:
+ *
+ *   a == Odd number (relatively prime to 2^n), and (a-1) is a multiple of 4.
+ *   c == Odd number (relatively prime to 2^n).
+ *   m == 2^32
+ *
+ * See Knuth's TAOCP 3rd Ed., Vol. 2, pg. 17 for details on these constraints.
+ *
+ * This choice of m has the disadvantage that the quality of the bits is
+ * proportional to bit position.  For example. the lowest bit has a cycle of 2,
+ * the next has a cycle of 4, etc.  For this reason, we prefer to use the upper
+ * bits.
+ */
+#  define PRN_DEFINE(suffix, var, a, c)					\
+static inline void							\
+sprn_##suffix(uint32_t seed)						\
+{									\
+	var = seed;							\
+}									\
+									\
+static inline uint32_t							\
+prn_##suffix(uint32_t lg_range)						\
+{									\
+	uint32_t ret, x;						\
+									\
+	assert(lg_range > 0);						\
+	assert(lg_range <= 32);						\
+									\
+	x = (var * (a)) + (c);						\
+	var = x;							\
+	ret = x >> (32 - lg_range);					\
+									\
+	return (ret);							\
+}
+#  define SPRN(suffix, seed)	sprn_##suffix(seed)
+#  define PRN(suffix, lg_range)	prn_##suffix(lg_range)
+#endif
+
+#ifdef MALLOC_BALANCE
+/* Define the PRNG used for arena assignment. */
+static __thread uint32_t balance_x;
+PRN_DEFINE(balance, balance_x, 1297, 1301)
+#endif
+
+static void
+wrtmessage(const char *p1, const char *p2, const char *p3, const char *p4)
+{
+
+	_write(STDERR_FILENO, p1, strlen(p1));
+	_write(STDERR_FILENO, p2, strlen(p2));
+	_write(STDERR_FILENO, p3, strlen(p3));
+	_write(STDERR_FILENO, p4, strlen(p4));
+}
+
+void	(*_malloc_message)(const char *p1, const char *p2, const char *p3,
+	    const char *p4) = wrtmessage;
+
+#ifdef MALLOC_STATS
+/*
+ * Print to stderr in such a way as to (hopefully) avoid memory allocation.
+ */
+static void
+malloc_printf(const char *format, ...)
+{
+	char buf[4096];
+	va_list ap;
+
+	va_start(ap, format);
+	vsnprintf(buf, sizeof(buf), format, ap);
+	va_end(ap);
+	_malloc_message(buf, "", "", "");
+}
+#endif
+
+/*
+ * We don't want to depend on vsnprintf() for production builds, since that can
+ * cause unnecessary bloat for static binaries.  umax2s() provides minimal
+ * integer printing functionality, so that malloc_printf() use can be limited to
+ * MALLOC_STATS code.
+ */
+#define	UMAX2S_BUFSIZE	21
+static char *
+umax2s(uintmax_t x, char *s)
+{
+	unsigned i;
+
+	/* Make sure UMAX2S_BUFSIZE is large enough. */
+	assert(sizeof(uintmax_t) <= 8);
+
+	i = UMAX2S_BUFSIZE - 1;
+	s[i] = '\0';
+	do {
+		i--;
+		s[i] = "0123456789"[x % 10];
+		x /= 10;
+	} while (x > 0);
+
+	return (&s[i]);
+}
+
+/******************************************************************************/
+
+#ifdef MALLOC_DSS
+static bool
+base_pages_alloc_dss(size_t minsize)
+{
+
+	/*
+	 * Do special DSS allocation here, since base allocations don't need to
+	 * be chunk-aligned.
+	 */
+	malloc_mutex_lock(&dss_mtx);
+	if (dss_prev != (void *)-1) {
+		intptr_t incr;
+		size_t csize = CHUNK_CEILING(minsize);
+
+		do {
+			/* Get the current end of the DSS. */
+			dss_max = sbrk(0);
+
+			/*
+			 * Calculate how much padding is necessary to
+			 * chunk-align the end of the DSS.  Don't worry about
+			 * dss_max not being chunk-aligned though.
+			 */
+			incr = (intptr_t)chunksize
+			    - (intptr_t)CHUNK_ADDR2OFFSET(dss_max);
+			assert(incr >= 0);
+			if ((size_t)incr < minsize)
+				incr += csize;
+
+			dss_prev = sbrk(incr);
+			if (dss_prev == dss_max) {
+				/* Success. */
+				dss_max = (void *)((intptr_t)dss_prev + incr);
+				base_pages = dss_prev;
+				base_next_addr = base_pages;
+				base_past_addr = dss_max;
+#ifdef MALLOC_STATS
+				base_mapped += incr;
+#endif
+				malloc_mutex_unlock(&dss_mtx);
+				return (false);
+			}
+		} while (dss_prev != (void *)-1);
+	}
+	malloc_mutex_unlock(&dss_mtx);
+
+	return (true);
+}
+#endif
+
+static bool
+base_pages_alloc_mmap(size_t minsize)
+{
+	size_t csize;
+
+	assert(minsize != 0);
+	csize = PAGE_CEILING(minsize);
+	base_pages = pages_map(NULL, csize);
+	if (base_pages == NULL)
+		return (true);
+	base_next_addr = base_pages;
+	base_past_addr = (void *)((uintptr_t)base_pages + csize);
+#ifdef MALLOC_STATS
+	base_mapped += csize;
+#endif
+
+	return (false);
+}
+
+static bool
+base_pages_alloc(size_t minsize)
+{
+
+#ifdef MALLOC_DSS
+	if (opt_dss) {
+		if (base_pages_alloc_dss(minsize) == false)
+			return (false);
+	}
+
+	if (opt_mmap && minsize != 0)
+#endif
+	{
+		if (base_pages_alloc_mmap(minsize) == false)
+			return (false);
+	}
+
+	return (true);
+}
+
+static void *
+base_alloc(size_t size)
+{
+	void *ret;
+	size_t csize;
+
+	/* Round size up to nearest multiple of the cacheline size. */
+	csize = CACHELINE_CEILING(size);
+
+	malloc_mutex_lock(&base_mtx);
+	/* Make sure there's enough space for the allocation. */
+	if ((uintptr_t)base_next_addr + csize > (uintptr_t)base_past_addr) {
+		if (base_pages_alloc(csize)) {
+			malloc_mutex_unlock(&base_mtx);
+			return (NULL);
+		}
+	}
+	/* Allocate. */
+	ret = base_next_addr;
+	base_next_addr = (void *)((uintptr_t)base_next_addr + csize);
+	malloc_mutex_unlock(&base_mtx);
+
+	return (ret);
+}
+
+static void *
+base_calloc(size_t number, size_t size)
+{
+	void *ret;
+
+	ret = base_alloc(number * size);
+	memset(ret, 0, number * size);
+
+	return (ret);
+}
+
+static extent_node_t *
+base_node_alloc(void)
+{
+	extent_node_t *ret;
+
+	malloc_mutex_lock(&base_mtx);
+	if (base_nodes != NULL) {
+		ret = base_nodes;
+		base_nodes = *(extent_node_t **)ret;
+		malloc_mutex_unlock(&base_mtx);
+	} else {
+		malloc_mutex_unlock(&base_mtx);
+		ret = (extent_node_t *)base_alloc(sizeof(extent_node_t));
+	}
+
+	return (ret);
+}
+
+static void
+base_node_dealloc(extent_node_t *node)
+{
+
+	malloc_mutex_lock(&base_mtx);
+	*(extent_node_t **)node = base_nodes;
+	base_nodes = node;
+	malloc_mutex_unlock(&base_mtx);
+}
+
+/******************************************************************************/
+
+#ifdef MALLOC_STATS
+static void
+stats_print(arena_t *arena)
+{
+	unsigned i, gap_start;
+
+	malloc_printf("dirty: %zu page%s dirty, %llu sweep%s,"
+	    " %llu madvise%s, %llu page%s purged\n",
+	    arena->ndirty, arena->ndirty == 1 ? "" : "s",
+	    arena->stats.npurge, arena->stats.npurge == 1 ? "" : "s",
+	    arena->stats.nmadvise, arena->stats.nmadvise == 1 ? "" : "s",
+	    arena->stats.purged, arena->stats.purged == 1 ? "" : "s");
+
+	malloc_printf("            allocated      nmalloc      ndalloc\n");
+	malloc_printf("small:   %12zu %12llu %12llu\n",
+	    arena->stats.allocated_small, arena->stats.nmalloc_small,
+	    arena->stats.ndalloc_small);
+	malloc_printf("large:   %12zu %12llu %12llu\n",
+	    arena->stats.allocated_large, arena->stats.nmalloc_large,
+	    arena->stats.ndalloc_large);
+	malloc_printf("total:   %12zu %12llu %12llu\n",
+	    arena->stats.allocated_small + arena->stats.allocated_large,
+	    arena->stats.nmalloc_small + arena->stats.nmalloc_large,
+	    arena->stats.ndalloc_small + arena->stats.ndalloc_large);
+	malloc_printf("mapped:  %12zu\n", arena->stats.mapped);
+
+#ifdef MALLOC_MAG
+	if (__isthreaded && opt_mag) {
+		malloc_printf("bins:     bin   size regs pgs      mags   "
+		    "newruns    reruns maxruns curruns\n");
+	} else {
+#endif
+		malloc_printf("bins:     bin   size regs pgs  requests   "
+		    "newruns    reruns maxruns curruns\n");
+#ifdef MALLOC_MAG
+	}
+#endif
+	for (i = 0, gap_start = UINT_MAX; i < nbins; i++) {
+		if (arena->bins[i].stats.nruns == 0) {
+			if (gap_start == UINT_MAX)
+				gap_start = i;
+		} else {
+			if (gap_start != UINT_MAX) {
+				if (i > gap_start + 1) {
+					/* Gap of more than one size class. */
+					malloc_printf("[%u..%u]\n",
+					    gap_start, i - 1);
+				} else {
+					/* Gap of one size class. */
+					malloc_printf("[%u]\n", gap_start);
+				}
+				gap_start = UINT_MAX;
+			}
+			malloc_printf(
+			    "%13u %1s %4u %4u %3u %9llu %9llu"
+			    " %9llu %7lu %7lu\n",
+			    i,
+			    i < ntbins ? "T" : i < ntbins + nqbins ? "Q" :
+			    i < ntbins + nqbins + ncbins ? "C" : "S",
+			    arena->bins[i].reg_size,
+			    arena->bins[i].nregs,
+			    arena->bins[i].run_size >> pagesize_2pow,
+#ifdef MALLOC_MAG
+			    (__isthreaded && opt_mag) ?
+			    arena->bins[i].stats.nmags :
+#endif
+			    arena->bins[i].stats.nrequests,
+			    arena->bins[i].stats.nruns,
+			    arena->bins[i].stats.reruns,
+			    arena->bins[i].stats.highruns,
+			    arena->bins[i].stats.curruns);
+		}
+	}
+	if (gap_start != UINT_MAX) {
+		if (i > gap_start + 1) {
+			/* Gap of more than one size class. */
+			malloc_printf("[%u..%u]\n", gap_start, i - 1);
+		} else {
+			/* Gap of one size class. */
+			malloc_printf("[%u]\n", gap_start);
+		}
+	}
+}
+#endif
+
+/*
+ * End Utility functions/macros.
+ */
+/******************************************************************************/
+/*
+ * Begin extent tree code.
+ */
+
+#ifdef MALLOC_DSS
+static inline int
+extent_szad_comp(extent_node_t *a, extent_node_t *b)
+{
+	int ret;
+	size_t a_size = a->size;
+	size_t b_size = b->size;
+
+	ret = (a_size > b_size) - (a_size < b_size);
+	if (ret == 0) {
+		uintptr_t a_addr = (uintptr_t)a->addr;
+		uintptr_t b_addr = (uintptr_t)b->addr;
+
+		ret = (a_addr > b_addr) - (a_addr < b_addr);
+	}
+
+	return (ret);
+}
+
+/* Wrap red-black tree macros in functions. */
+rb_wrap(__unused static, extent_tree_szad_, extent_tree_t, extent_node_t,
+    link_szad, extent_szad_comp)
+#endif
+
+static inline int
+extent_ad_comp(extent_node_t *a, extent_node_t *b)
+{
+	uintptr_t a_addr = (uintptr_t)a->addr;
+	uintptr_t b_addr = (uintptr_t)b->addr;
+
+	return ((a_addr > b_addr) - (a_addr < b_addr));
+}
+
+/* Wrap red-black tree macros in functions. */
+rb_wrap(__unused static, extent_tree_ad_, extent_tree_t, extent_node_t, link_ad,
+    extent_ad_comp)
+
+/*
+ * End extent tree code.
+ */
+/******************************************************************************/
+/*
+ * Begin chunk management functions.
+ */
+
+static void *
+pages_map(void *addr, size_t size)
+{
+	void *ret;
+
+	/*
+	 * We don't use MAP_FIXED here, because it can cause the *replacement*
+	 * of existing mappings, and we only want to create new mappings.
+	 */
+	ret = mmap(addr, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON,
+	    -1, 0);
+	assert(ret != NULL);
+
+	if (ret == MAP_FAILED)
+		ret = NULL;
+	else if (addr != NULL && ret != addr) {
+		/*
+		 * We succeeded in mapping memory, but not in the right place.
+		 */
+		if (munmap(ret, size) == -1) {
+			char buf[STRERROR_BUF];
+
+			strerror_r(errno, buf, sizeof(buf));
+			_malloc_message(_getprogname(),
+			    ": (malloc) Error in munmap(): ", buf, "\n");
+			if (opt_abort)
+				abort();
+		}
+		ret = NULL;
+	}
+
+	assert(ret == NULL || (addr == NULL && ret != addr)
+	    || (addr != NULL && ret == addr));
+	return (ret);
+}
+
+static void
+pages_unmap(void *addr, size_t size)
+{
+
+	if (munmap(addr, size) == -1) {
+		char buf[STRERROR_BUF];
+
+		strerror_r(errno, buf, sizeof(buf));
+		_malloc_message(_getprogname(),
+		    ": (malloc) Error in munmap(): ", buf, "\n");
+		if (opt_abort)
+			abort();
+	}
+}
+
+#ifdef MALLOC_DSS
+static void *
+chunk_alloc_dss(size_t size)
+{
+
+	/*
+	 * sbrk() uses a signed increment argument, so take care not to
+	 * interpret a huge allocation request as a negative increment.
+	 */
+	if ((intptr_t)size < 0)
+		return (NULL);
+
+	malloc_mutex_lock(&dss_mtx);
+	if (dss_prev != (void *)-1) {
+		intptr_t incr;
+
+		/*
+		 * The loop is necessary to recover from races with other
+		 * threads that are using the DSS for something other than
+		 * malloc.
+		 */
+		do {
+			void *ret;
+
+			/* Get the current end of the DSS. */
+			dss_max = sbrk(0);
+
+			/*
+			 * Calculate how much padding is necessary to
+			 * chunk-align the end of the DSS.
+			 */
+			incr = (intptr_t)size
+			    - (intptr_t)CHUNK_ADDR2OFFSET(dss_max);
+			if (incr == (intptr_t)size)
+				ret = dss_max;
+			else {
+				ret = (void *)((intptr_t)dss_max + incr);
+				incr += size;
+			}
+
+			dss_prev = sbrk(incr);
+			if (dss_prev == dss_max) {
+				/* Success. */
+				dss_max = (void *)((intptr_t)dss_prev + incr);
+				malloc_mutex_unlock(&dss_mtx);
+				return (ret);
+			}
+		} while (dss_prev != (void *)-1);
+	}
+	malloc_mutex_unlock(&dss_mtx);
+
+	return (NULL);
+}
+
+static void *
+chunk_recycle_dss(size_t size, bool zero)
+{
+	extent_node_t *node, key;
+
+	key.addr = NULL;
+	key.size = size;
+	malloc_mutex_lock(&dss_mtx);
+	node = extent_tree_szad_nsearch(&dss_chunks_szad, &key);
+	if (node != NULL) {
+		void *ret = node->addr;
+
+		/* Remove node from the tree. */
+		extent_tree_szad_remove(&dss_chunks_szad, node);
+		if (node->size == size) {
+			extent_tree_ad_remove(&dss_chunks_ad, node);
+			base_node_dealloc(node);
+		} else {
+			/*
+			 * Insert the remainder of node's address range as a
+			 * smaller chunk.  Its position within dss_chunks_ad
+			 * does not change.
+			 */
+			assert(node->size > size);
+			node->addr = (void *)((uintptr_t)node->addr + size);
+			node->size -= size;
+			extent_tree_szad_insert(&dss_chunks_szad, node);
+		}
+		malloc_mutex_unlock(&dss_mtx);
+
+		if (zero)
+			memset(ret, 0, size);
+		return (ret);
+	}
+	malloc_mutex_unlock(&dss_mtx);
+
+	return (NULL);
+}
+#endif
+
+static void *
+chunk_alloc_mmap(size_t size)
+{
+	void *ret;
+	size_t offset;
+
+	/*
+	 * Ideally, there would be a way to specify alignment to mmap() (like
+	 * NetBSD has), but in the absence of such a feature, we have to work
+	 * hard to efficiently create aligned mappings.  The reliable, but
+	 * expensive method is to create a mapping that is over-sized, then
+	 * trim the excess.  However, that always results in at least one call
+	 * to pages_unmap().
+	 *
+	 * A more optimistic approach is to try mapping precisely the right
+	 * amount, then try to append another mapping if alignment is off.  In
+	 * practice, this works out well as long as the application is not
+	 * interleaving mappings via direct mmap() calls.  If we do run into a
+	 * situation where there is an interleaved mapping and we are unable to
+	 * extend an unaligned mapping, our best option is to momentarily
+	 * revert to the reliable-but-expensive method.  This will tend to
+	 * leave a gap in the memory map that is too small to cause later
+	 * problems for the optimistic method.
+	 */
+
+	ret = pages_map(NULL, size);
+	if (ret == NULL)
+		return (NULL);
+
+	offset = CHUNK_ADDR2OFFSET(ret);
+	if (offset != 0) {
+		/* Try to extend chunk boundary. */
+		if (pages_map((void *)((uintptr_t)ret + size),
+		    chunksize - offset) == NULL) {
+			/*
+			 * Extension failed.  Clean up, then revert to the
+			 * reliable-but-expensive method.
+			 */
+			pages_unmap(ret, size);
+
+			/* Beware size_t wrap-around. */
+			if (size + chunksize <= size)
+				return NULL;
+
+			ret = pages_map(NULL, size + chunksize);
+			if (ret == NULL)
+				return (NULL);
+
+			/* Clean up unneeded leading/trailing space. */
+			offset = CHUNK_ADDR2OFFSET(ret);
+			if (offset != 0) {
+				/* Leading space. */
+				pages_unmap(ret, chunksize - offset);
+
+				ret = (void *)((uintptr_t)ret +
+				    (chunksize - offset));
+
+				/* Trailing space. */
+				pages_unmap((void *)((uintptr_t)ret + size),
+				    offset);
+			} else {
+				/* Trailing space only. */
+				pages_unmap((void *)((uintptr_t)ret + size),
+				    chunksize);
+			}
+		} else {
+			/* Clean up unneeded leading space. */
+			pages_unmap(ret, chunksize - offset);
+			ret = (void *)((uintptr_t)ret + (chunksize - offset));
+		}
+	}
+
+	return (ret);
+}
+
+static void *
+chunk_alloc(size_t size, bool zero)
+{
+	void *ret;
+
+	assert(size != 0);
+	assert((size & chunksize_mask) == 0);
+
+#ifdef MALLOC_DSS
+	if (opt_dss) {
+		ret = chunk_recycle_dss(size, zero);
+		if (ret != NULL) {
+			goto RETURN;
+		}
+
+		ret = chunk_alloc_dss(size);
+		if (ret != NULL)
+			goto RETURN;
+	}
+
+	if (opt_mmap)
+#endif
+	{
+		ret = chunk_alloc_mmap(size);
+		if (ret != NULL)
+			goto RETURN;
+	}
+
+	/* All strategies for allocation failed. */
+	ret = NULL;
+RETURN:
+#ifdef MALLOC_STATS
+	if (ret != NULL) {
+		stats_chunks.nchunks += (size / chunksize);
+		stats_chunks.curchunks += (size / chunksize);
+	}
+	if (stats_chunks.curchunks > stats_chunks.highchunks)
+		stats_chunks.highchunks = stats_chunks.curchunks;
+#endif
+
+	assert(CHUNK_ADDR2BASE(ret) == ret);
+	return (ret);
+}
+
+#ifdef MALLOC_DSS
+static extent_node_t *
+chunk_dealloc_dss_record(void *chunk, size_t size)
+{
+	extent_node_t *node, *prev, key;
+
+	key.addr = (void *)((uintptr_t)chunk + size);
+	node = extent_tree_ad_nsearch(&dss_chunks_ad, &key);
+	/* Try to coalesce forward. */
+	if (node != NULL && node->addr == key.addr) {
+		/*
+		 * Coalesce chunk with the following address range.  This does
+		 * not change the position within dss_chunks_ad, so only
+		 * remove/insert from/into dss_chunks_szad.
+		 */
+		extent_tree_szad_remove(&dss_chunks_szad, node);
+		node->addr = chunk;
+		node->size += size;
+		extent_tree_szad_insert(&dss_chunks_szad, node);
+	} else {
+		/*
+		 * Coalescing forward failed, so insert a new node.  Drop
+		 * dss_mtx during node allocation, since it is possible that a
+		 * new base chunk will be allocated.
+		 */
+		malloc_mutex_unlock(&dss_mtx);
+		node = base_node_alloc();
+		malloc_mutex_lock(&dss_mtx);
+		if (node == NULL)
+			return (NULL);
+		node->addr = chunk;
+		node->size = size;
+		extent_tree_ad_insert(&dss_chunks_ad, node);
+		extent_tree_szad_insert(&dss_chunks_szad, node);
+	}
+
+	/* Try to coalesce backward. */
+	prev = extent_tree_ad_prev(&dss_chunks_ad, node);
+	if (prev != NULL && (void *)((uintptr_t)prev->addr + prev->size) ==
+	    chunk) {
+		/*
+		 * Coalesce chunk with the previous address range.  This does
+		 * not change the position within dss_chunks_ad, so only
+		 * remove/insert node from/into dss_chunks_szad.
+		 */
+		extent_tree_szad_remove(&dss_chunks_szad, prev);
+		extent_tree_ad_remove(&dss_chunks_ad, prev);
+
+		extent_tree_szad_remove(&dss_chunks_szad, node);
+		node->addr = prev->addr;
+		node->size += prev->size;
+		extent_tree_szad_insert(&dss_chunks_szad, node);
+
+		base_node_dealloc(prev);
+	}
+
+	return (node);
+}
+
+static bool
+chunk_dealloc_dss(void *chunk, size_t size)
+{
+
+	malloc_mutex_lock(&dss_mtx);
+	if ((uintptr_t)chunk >= (uintptr_t)dss_base
+	    && (uintptr_t)chunk < (uintptr_t)dss_max) {
+		extent_node_t *node;
+
+		/* Try to coalesce with other unused chunks. */
+		node = chunk_dealloc_dss_record(chunk, size);
+		if (node != NULL) {
+			chunk = node->addr;
+			size = node->size;
+		}
+
+		/* Get the current end of the DSS. */
+		dss_max = sbrk(0);
+
+		/*
+		 * Try to shrink the DSS if this chunk is at the end of the
+		 * DSS.  The sbrk() call here is subject to a race condition
+		 * with threads that use brk(2) or sbrk(2) directly, but the
+		 * alternative would be to leak memory for the sake of poorly
+		 * designed multi-threaded programs.
+		 */
+		if ((void *)((uintptr_t)chunk + size) == dss_max
+		    && (dss_prev = sbrk(-(intptr_t)size)) == dss_max) {
+			/* Success. */
+			dss_max = (void *)((intptr_t)dss_prev - (intptr_t)size);
+
+			if (node != NULL) {
+				extent_tree_szad_remove(&dss_chunks_szad, node);
+				extent_tree_ad_remove(&dss_chunks_ad, node);
+				base_node_dealloc(node);
+			}
+			malloc_mutex_unlock(&dss_mtx);
+		} else {
+			malloc_mutex_unlock(&dss_mtx);
+			madvise(chunk, size, MADV_FREE);
+		}
+
+		return (false);
+	}
+	malloc_mutex_unlock(&dss_mtx);
+
+	return (true);
+}
+#endif
+
+static void
+chunk_dealloc_mmap(void *chunk, size_t size)
+{
+
+	pages_unmap(chunk, size);
+}
+
+static void
+chunk_dealloc(void *chunk, size_t size)
+{
+
+	assert(chunk != NULL);
+	assert(CHUNK_ADDR2BASE(chunk) == chunk);
+	assert(size != 0);
+	assert((size & chunksize_mask) == 0);
+
+#ifdef MALLOC_STATS
+	stats_chunks.curchunks -= (size / chunksize);
+#endif
+
+#ifdef MALLOC_DSS
+	if (opt_dss) {
+		if (chunk_dealloc_dss(chunk, size) == false)
+			return;
+	}
+
+	if (opt_mmap)
+#endif
+		chunk_dealloc_mmap(chunk, size);
+}
+
+/*
+ * End chunk management functions.
+ */
+/******************************************************************************/
+/*
+ * Begin arena.
+ */
+
+/*
+ * Choose an arena based on a per-thread value (fast-path code, calls slow-path
+ * code if necessary).
+ */
+static inline arena_t *
+choose_arena(void)
+{
+	arena_t *ret;
+
+	/*
+	 * We can only use TLS if this is a PIC library, since for the static
+	 * library version, libc's malloc is used by TLS allocation, which
+	 * introduces a bootstrapping issue.
+	 */
+#ifndef NO_TLS
+	if (__isthreaded == false) {
+	    /* Avoid the overhead of TLS for single-threaded operation. */
+	    return (arenas[0]);
+	}
+
+	ret = arenas_map;
+	if (ret == NULL) {
+		ret = choose_arena_hard();
+		assert(ret != NULL);
+	}
+#else
+	if (__isthreaded && narenas > 1) {
+		unsigned long ind;
+
+		/*
+		 * Hash _pthread_self() to one of the arenas.  There is a prime
+		 * number of arenas, so this has a reasonable chance of
+		 * working.  Even so, the hashing can be easily thwarted by
+		 * inconvenient _pthread_self() values.  Without specific
+		 * knowledge of how _pthread_self() calculates values, we can't
+		 * easily do much better than this.
+		 */
+		ind = (unsigned long) _pthread_self() % narenas;
+
+		/*
+		 * Optimistially assume that arenas[ind] has been initialized.
+		 * At worst, we find out that some other thread has already
+		 * done so, after acquiring the lock in preparation.  Note that
+		 * this lazy locking also has the effect of lazily forcing
+		 * cache coherency; without the lock acquisition, there's no
+		 * guarantee that modification of arenas[ind] by another thread
+		 * would be seen on this CPU for an arbitrary amount of time.
+		 *
+		 * In general, this approach to modifying a synchronized value
+		 * isn't a good idea, but in this case we only ever modify the
+		 * value once, so things work out well.
+		 */
+		ret = arenas[ind];
+		if (ret == NULL) {
+			/*
+			 * Avoid races with another thread that may have already
+			 * initialized arenas[ind].
+			 */
+			malloc_spin_lock(&arenas_lock);
+			if (arenas[ind] == NULL)
+				ret = arenas_extend((unsigned)ind);
+			else
+				ret = arenas[ind];
+			malloc_spin_unlock(&arenas_lock);
+		}
+	} else
+		ret = arenas[0];
+#endif
+
+	assert(ret != NULL);
+	return (ret);
+}
+
+#ifndef NO_TLS
+/*
+ * Choose an arena based on a per-thread value (slow-path code only, called
+ * only by choose_arena()).
+ */
+static arena_t *
+choose_arena_hard(void)
+{
+	arena_t *ret;
+
+	assert(__isthreaded);
+
+#ifdef MALLOC_BALANCE
+	/* Seed the PRNG used for arena load balancing. */
+	SPRN(balance, (uint32_t)(uintptr_t)(_pthread_self()));
+#endif
+
+	if (narenas > 1) {
+#ifdef MALLOC_BALANCE
+		unsigned ind;
+
+		ind = PRN(balance, narenas_2pow);
+		if ((ret = arenas[ind]) == NULL) {
+			malloc_spin_lock(&arenas_lock);
+			if ((ret = arenas[ind]) == NULL)
+				ret = arenas_extend(ind);
+			malloc_spin_unlock(&arenas_lock);
+		}
+#else
+		malloc_spin_lock(&arenas_lock);
+		if ((ret = arenas[next_arena]) == NULL)
+			ret = arenas_extend(next_arena);
+		next_arena = (next_arena + 1) % narenas;
+		malloc_spin_unlock(&arenas_lock);
+#endif
+	} else
+		ret = arenas[0];
+
+	arenas_map = ret;
+
+	return (ret);
+}
+#endif
+
+static inline int
+arena_chunk_comp(arena_chunk_t *a, arena_chunk_t *b)
+{
+	uintptr_t a_chunk = (uintptr_t)a;
+	uintptr_t b_chunk = (uintptr_t)b;
+
+	assert(a != NULL);
+	assert(b != NULL);
+
+	return ((a_chunk > b_chunk) - (a_chunk < b_chunk));
+}
+
+/* Wrap red-black tree macros in functions. */
+rb_wrap(__unused static, arena_chunk_tree_dirty_, arena_chunk_tree_t,
+    arena_chunk_t, link_dirty, arena_chunk_comp)
+
+static inline int
+arena_run_comp(arena_chunk_map_t *a, arena_chunk_map_t *b)
+{
+	uintptr_t a_mapelm = (uintptr_t)a;
+	uintptr_t b_mapelm = (uintptr_t)b;
+
+	assert(a != NULL);
+	assert(b != NULL);
+
+	return ((a_mapelm > b_mapelm) - (a_mapelm < b_mapelm));
+}
+
+/* Wrap red-black tree macros in functions. */
+rb_wrap(__unused static, arena_run_tree_, arena_run_tree_t, arena_chunk_map_t,
+    link, arena_run_comp)
+
+static inline int
+arena_avail_comp(arena_chunk_map_t *a, arena_chunk_map_t *b)
+{
+	int ret;
+	size_t a_size = a->bits & ~pagesize_mask;
+	size_t b_size = b->bits & ~pagesize_mask;
+
+	ret = (a_size > b_size) - (a_size < b_size);
+	if (ret == 0) {
+		uintptr_t a_mapelm, b_mapelm;
+
+		if ((a->bits & CHUNK_MAP_KEY) == 0)
+			a_mapelm = (uintptr_t)a;
+		else {
+			/*
+			 * Treat keys as though they are lower than anything
+			 * else.
+			 */
+			a_mapelm = 0;
+		}
+		b_mapelm = (uintptr_t)b;
+
+		ret = (a_mapelm > b_mapelm) - (a_mapelm < b_mapelm);
+	}
+
+	return (ret);
+}
+
+/* Wrap red-black tree macros in functions. */
+rb_wrap(__unused static, arena_avail_tree_, arena_avail_tree_t,
+    arena_chunk_map_t, link, arena_avail_comp)
+
+static inline void *
+arena_run_reg_alloc(arena_run_t *run, arena_bin_t *bin)
+{
+	void *ret;
+	unsigned i, mask, bit, regind;
+
+	assert(run->magic == ARENA_RUN_MAGIC);
+	assert(run->regs_minelm < bin->regs_mask_nelms);
+
+	/*
+	 * Move the first check outside the loop, so that run->regs_minelm can
+	 * be updated unconditionally, without the possibility of updating it
+	 * multiple times.
+	 */
+	i = run->regs_minelm;
+	mask = run->regs_mask[i];
+	if (mask != 0) {
+		/* Usable allocation found. */
+		bit = ffs((int)mask) - 1;
+
+		regind = ((i << (SIZEOF_INT_2POW + 3)) + bit);
+		assert(regind < bin->nregs);
+		ret = (void *)(((uintptr_t)run) + bin->reg0_offset
+		    + (bin->reg_size * regind));
+
+		/* Clear bit. */
+		mask ^= (1U << bit);
+		run->regs_mask[i] = mask;
+
+		return (ret);
+	}
+
+	for (i++; i < bin->regs_mask_nelms; i++) {
+		mask = run->regs_mask[i];
+		if (mask != 0) {
+			/* Usable allocation found. */
+			bit = ffs((int)mask) - 1;
+
+			regind = ((i << (SIZEOF_INT_2POW + 3)) + bit);
+			assert(regind < bin->nregs);
+			ret = (void *)(((uintptr_t)run) + bin->reg0_offset
+			    + (bin->reg_size * regind));
+
+			/* Clear bit. */
+			mask ^= (1U << bit);
+			run->regs_mask[i] = mask;
+
+			/*
+			 * Make a note that nothing before this element
+			 * contains a free region.
+			 */
+			run->regs_minelm = i; /* Low payoff: + (mask == 0); */
+
+			return (ret);
+		}
+	}
+	/* Not reached. */
+	assert(0);
+	return (NULL);
+}
+
+static inline void
+arena_run_reg_dalloc(arena_run_t *run, arena_bin_t *bin, void *ptr, size_t size)
+{
+	unsigned diff, regind, elm, bit;
+
+	assert(run->magic == ARENA_RUN_MAGIC);
+
+	/*
+	 * Avoid doing division with a variable divisor if possible.  Using
+	 * actual division here can reduce allocator throughput by over 20%!
+	 */
+	diff = (unsigned)((uintptr_t)ptr - (uintptr_t)run - bin->reg0_offset);
+	if ((size & (size - 1)) == 0) {
+		/*
+		 * log2_table allows fast division of a power of two in the
+		 * [1..128] range.
+		 *
+		 * (x / divisor) becomes (x >> log2_table[divisor - 1]).
+		 */
+		static const unsigned char log2_table[] = {
+		    0, 1, 0, 2, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 4,
+		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5,
+		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6,
+		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+		    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7
+		};
+
+		if (size <= 128)
+			regind = (diff >> log2_table[size - 1]);
+		else if (size <= 32768)
+			regind = diff >> (8 + log2_table[(size >> 8) - 1]);
+		else
+			regind = diff / size;
+	} else if (size < qspace_max) {
+		/*
+		 * To divide by a number D that is not a power of two we
+		 * multiply by (2^21 / D) and then right shift by 21 positions.
+		 *
+		 *   X / D
+		 *
+		 * becomes
+		 *
+		 *   (X * qsize_invs[(D >> QUANTUM_2POW) - 3])
+		 *       >> SIZE_INV_SHIFT
+		 *
+		 * We can omit the first three elements, because we never
+		 * divide by 0, and QUANTUM and 2*QUANTUM are both powers of
+		 * two, which are handled above.
+		 */
+#define	SIZE_INV_SHIFT 21
+#define	QSIZE_INV(s) (((1U << SIZE_INV_SHIFT) / (s << QUANTUM_2POW)) + 1)
+		static const unsigned qsize_invs[] = {
+		    QSIZE_INV(3),
+		    QSIZE_INV(4), QSIZE_INV(5), QSIZE_INV(6), QSIZE_INV(7)
+#if (QUANTUM_2POW < 4)
+		    ,
+		    QSIZE_INV(8), QSIZE_INV(9), QSIZE_INV(10), QSIZE_INV(11),
+		    QSIZE_INV(12),QSIZE_INV(13), QSIZE_INV(14), QSIZE_INV(15)
+#endif
+		};
+		assert(QUANTUM * (((sizeof(qsize_invs)) / sizeof(unsigned)) + 3)
+		    >= (1U << QSPACE_MAX_2POW_DEFAULT));
+
+		if (size <= (((sizeof(qsize_invs) / sizeof(unsigned)) + 2) <<
+		    QUANTUM_2POW)) {
+			regind = qsize_invs[(size >> QUANTUM_2POW) - 3] * diff;
+			regind >>= SIZE_INV_SHIFT;
+		} else
+			regind = diff / size;
+#undef QSIZE_INV
+	} else if (size < cspace_max) {
+#define	CSIZE_INV(s) (((1U << SIZE_INV_SHIFT) / (s << CACHELINE_2POW)) + 1)
+		static const unsigned csize_invs[] = {
+		    CSIZE_INV(3),
+		    CSIZE_INV(4), CSIZE_INV(5), CSIZE_INV(6), CSIZE_INV(7)
+		};
+		assert(CACHELINE * (((sizeof(csize_invs)) / sizeof(unsigned)) +
+		    3) >= (1U << CSPACE_MAX_2POW_DEFAULT));
+
+		if (size <= (((sizeof(csize_invs) / sizeof(unsigned)) + 2) <<
+		    CACHELINE_2POW)) {
+			regind = csize_invs[(size >> CACHELINE_2POW) - 3] *
+			    diff;
+			regind >>= SIZE_INV_SHIFT;
+		} else
+			regind = diff / size;
+#undef CSIZE_INV
+	} else {
+#define	SSIZE_INV(s) (((1U << SIZE_INV_SHIFT) / (s << SUBPAGE_2POW)) + 1)
+		static const unsigned ssize_invs[] = {
+		    SSIZE_INV(3),
+		    SSIZE_INV(4), SSIZE_INV(5), SSIZE_INV(6), SSIZE_INV(7),
+		    SSIZE_INV(8), SSIZE_INV(9), SSIZE_INV(10), SSIZE_INV(11),
+		    SSIZE_INV(12), SSIZE_INV(13), SSIZE_INV(14), SSIZE_INV(15)
+#if (PAGESIZE_2POW == 13)
+		    ,
+		    SSIZE_INV(16), SSIZE_INV(17), SSIZE_INV(18), SSIZE_INV(19),
+		    SSIZE_INV(20), SSIZE_INV(21), SSIZE_INV(22), SSIZE_INV(23),
+		    SSIZE_INV(24), SSIZE_INV(25), SSIZE_INV(26), SSIZE_INV(27),
+		    SSIZE_INV(28), SSIZE_INV(29), SSIZE_INV(29), SSIZE_INV(30)
+#endif
+		};
+		assert(SUBPAGE * (((sizeof(ssize_invs)) / sizeof(unsigned)) + 3)
+		    >= (1U << PAGESIZE_2POW));
+
+		if (size < (((sizeof(ssize_invs) / sizeof(unsigned)) + 2) <<
+		    SUBPAGE_2POW)) {
+			regind = ssize_invs[(size >> SUBPAGE_2POW) - 3] * diff;
+			regind >>= SIZE_INV_SHIFT;
+		} else
+			regind = diff / size;
+#undef SSIZE_INV
+	}
+#undef SIZE_INV_SHIFT
+	assert(diff == regind * size);
+	assert(regind < bin->nregs);
+
+	elm = regind >> (SIZEOF_INT_2POW + 3);
+	if (elm < run->regs_minelm)
+		run->regs_minelm = elm;
+	bit = regind - (elm << (SIZEOF_INT_2POW + 3));
+	assert((run->regs_mask[elm] & (1U << bit)) == 0);
+	run->regs_mask[elm] |= (1U << bit);
+}
+
+static void
+arena_run_split(arena_t *arena, arena_run_t *run, size_t size, bool large,
+    bool zero)
+{
+	arena_chunk_t *chunk;
+	size_t old_ndirty, run_ind, total_pages, need_pages, rem_pages, i;
+
+	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run);
+	old_ndirty = chunk->ndirty;
+	run_ind = (unsigned)(((uintptr_t)run - (uintptr_t)chunk)
+	    >> pagesize_2pow);
+	total_pages = (chunk->map[run_ind].bits & ~pagesize_mask) >>
+	    pagesize_2pow;
+	need_pages = (size >> pagesize_2pow);
+	assert(need_pages > 0);
+	assert(need_pages <= total_pages);
+	rem_pages = total_pages - need_pages;
+
+	arena_avail_tree_remove(&arena->runs_avail, &chunk->map[run_ind]);
+
+	/* Keep track of trailing unused pages for later use. */
+	if (rem_pages > 0) {
+		chunk->map[run_ind+need_pages].bits = (rem_pages <<
+		    pagesize_2pow) | (chunk->map[run_ind+need_pages].bits &
+		    pagesize_mask);
+		chunk->map[run_ind+total_pages-1].bits = (rem_pages <<
+		    pagesize_2pow) | (chunk->map[run_ind+total_pages-1].bits &
+		    pagesize_mask);
+		arena_avail_tree_insert(&arena->runs_avail,
+		    &chunk->map[run_ind+need_pages]);
+	}
+
+	for (i = 0; i < need_pages; i++) {
+		/* Zero if necessary. */
+		if (zero) {
+			if ((chunk->map[run_ind + i].bits & CHUNK_MAP_ZEROED)
+			    == 0) {
+				memset((void *)((uintptr_t)chunk + ((run_ind
+				    + i) << pagesize_2pow)), 0, pagesize);
+				/* CHUNK_MAP_ZEROED is cleared below. */
+			}
+		}
+
+		/* Update dirty page accounting. */
+		if (chunk->map[run_ind + i].bits & CHUNK_MAP_DIRTY) {
+			chunk->ndirty--;
+			arena->ndirty--;
+			/* CHUNK_MAP_DIRTY is cleared below. */
+		}
+
+		/* Initialize the chunk map. */
+		if (large) {
+			chunk->map[run_ind + i].bits = CHUNK_MAP_LARGE
+			    | CHUNK_MAP_ALLOCATED;
+		} else {
+			chunk->map[run_ind + i].bits = (size_t)run
+			    | CHUNK_MAP_ALLOCATED;
+		}
+	}
+
+	/*
+	 * Set the run size only in the first element for large runs.  This is
+	 * primarily a debugging aid, since the lack of size info for trailing
+	 * pages only matters if the application tries to operate on an
+	 * interior pointer.
+	 */
+	if (large)
+		chunk->map[run_ind].bits |= size;
+
+	if (chunk->ndirty == 0 && old_ndirty > 0)
+		arena_chunk_tree_dirty_remove(&arena->chunks_dirty, chunk);
+}
+
+static arena_chunk_t *
+arena_chunk_alloc(arena_t *arena)
+{
+	arena_chunk_t *chunk;
+	size_t i;
+
+	if (arena->spare != NULL) {
+		chunk = arena->spare;
+		arena->spare = NULL;
+	} else {
+		chunk = (arena_chunk_t *)chunk_alloc(chunksize, true);
+		if (chunk == NULL)
+			return (NULL);
+#ifdef MALLOC_STATS
+		arena->stats.mapped += chunksize;
+#endif
+
+		chunk->arena = arena;
+
+		/*
+		 * Claim that no pages are in use, since the header is merely
+		 * overhead.
+		 */
+		chunk->ndirty = 0;
+
+		/*
+		 * Initialize the map to contain one maximal free untouched run.
+		 */
+		for (i = 0; i < arena_chunk_header_npages; i++)
+			chunk->map[i].bits = 0;
+		chunk->map[i].bits = arena_maxclass | CHUNK_MAP_ZEROED;
+		for (i++; i < chunk_npages-1; i++) {
+			chunk->map[i].bits = CHUNK_MAP_ZEROED;
+		}
+		chunk->map[chunk_npages-1].bits = arena_maxclass |
+		    CHUNK_MAP_ZEROED;
+	}
+
+	/* Insert the run into the runs_avail tree. */
+	arena_avail_tree_insert(&arena->runs_avail,
+	    &chunk->map[arena_chunk_header_npages]);
+
+	return (chunk);
+}
+
+static void
+arena_chunk_dealloc(arena_t *arena, arena_chunk_t *chunk)
+{
+
+	if (arena->spare != NULL) {
+		if (arena->spare->ndirty > 0) {
+			arena_chunk_tree_dirty_remove(
+			    &chunk->arena->chunks_dirty, arena->spare);
+			arena->ndirty -= arena->spare->ndirty;
+		}
+		chunk_dealloc((void *)arena->spare, chunksize);
+#ifdef MALLOC_STATS
+		arena->stats.mapped -= chunksize;
+#endif
+	}
+
+	/*
+	 * Remove run from runs_avail, regardless of whether this chunk
+	 * will be cached, so that the arena does not use it.  Dirty page
+	 * flushing only uses the chunks_dirty tree, so leaving this chunk in
+	 * the chunks_* trees is sufficient for that purpose.
+	 */
+	arena_avail_tree_remove(&arena->runs_avail,
+	    &chunk->map[arena_chunk_header_npages]);
+
+	arena->spare = chunk;
+}
+
+static arena_run_t *
+arena_run_alloc(arena_t *arena, size_t size, bool large, bool zero)
+{
+	arena_chunk_t *chunk;
+	arena_run_t *run;
+	arena_chunk_map_t *mapelm, key;
+
+	assert(size <= arena_maxclass);
+	assert((size & pagesize_mask) == 0);
+
+	/* Search the arena's chunks for the lowest best fit. */
+	key.bits = size | CHUNK_MAP_KEY;
+	mapelm = arena_avail_tree_nsearch(&arena->runs_avail, &key);
+	if (mapelm != NULL) {
+		arena_chunk_t *run_chunk = CHUNK_ADDR2BASE(mapelm);
+		size_t pageind = ((uintptr_t)mapelm - (uintptr_t)run_chunk->map)
+		    / sizeof(arena_chunk_map_t);
+
+		run = (arena_run_t *)((uintptr_t)run_chunk + (pageind
+		    << pagesize_2pow));
+		arena_run_split(arena, run, size, large, zero);
+		return (run);
+	}
+
+	/*
+	 * No usable runs.  Create a new chunk from which to allocate the run.
+	 */
+	chunk = arena_chunk_alloc(arena);
+	if (chunk == NULL)
+		return (NULL);
+	run = (arena_run_t *)((uintptr_t)chunk + (arena_chunk_header_npages <<
+	    pagesize_2pow));
+	/* Update page map. */
+	arena_run_split(arena, run, size, large, zero);
+	return (run);
+}
+
+static void
+arena_purge(arena_t *arena)
+{
+	arena_chunk_t *chunk;
+	size_t i, npages;
+#ifdef MALLOC_DEBUG
+	size_t ndirty = 0;
+
+	rb_foreach_begin(arena_chunk_t, link_dirty, &arena->chunks_dirty,
+	    chunk) {
+		ndirty += chunk->ndirty;
+	} rb_foreach_end(arena_chunk_t, link_dirty, &arena->chunks_dirty, chunk)
+	assert(ndirty == arena->ndirty);
+#endif
+	assert(arena->ndirty > opt_dirty_max);
+
+#ifdef MALLOC_STATS
+	arena->stats.npurge++;
+#endif
+
+	/*
+	 * Iterate downward through chunks until enough dirty memory has been
+	 * purged.  Terminate as soon as possible in order to minimize the
+	 * number of system calls, even if a chunk has only been partially
+	 * purged.
+	 */
+	while (arena->ndirty > (opt_dirty_max >> 1)) {
+		chunk = arena_chunk_tree_dirty_last(&arena->chunks_dirty);
+		assert(chunk != NULL);
+
+		for (i = chunk_npages - 1; chunk->ndirty > 0; i--) {
+			assert(i >= arena_chunk_header_npages);
+
+			if (chunk->map[i].bits & CHUNK_MAP_DIRTY) {
+				chunk->map[i].bits ^= CHUNK_MAP_DIRTY;
+				/* Find adjacent dirty run(s). */
+				for (npages = 1; i > arena_chunk_header_npages
+				    && (chunk->map[i - 1].bits &
+				    CHUNK_MAP_DIRTY); npages++) {
+					i--;
+					chunk->map[i].bits ^= CHUNK_MAP_DIRTY;
+				}
+				chunk->ndirty -= npages;
+				arena->ndirty -= npages;
+
+				madvise((void *)((uintptr_t)chunk + (i <<
+				    pagesize_2pow)), (npages << pagesize_2pow),
+				    MADV_FREE);
+#ifdef MALLOC_STATS
+				arena->stats.nmadvise++;
+				arena->stats.purged += npages;
+#endif
+				if (arena->ndirty <= (opt_dirty_max >> 1))
+					break;
+			}
+		}
+
+		if (chunk->ndirty == 0) {
+			arena_chunk_tree_dirty_remove(&arena->chunks_dirty,
+			    chunk);
+		}
+	}
+}
+
+static void
+arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty)
+{
+	arena_chunk_t *chunk;
+	size_t size, run_ind, run_pages;
+
+	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run);
+	run_ind = (size_t)(((uintptr_t)run - (uintptr_t)chunk)
+	    >> pagesize_2pow);
+	assert(run_ind >= arena_chunk_header_npages);
+	assert(run_ind < chunk_npages);
+	if ((chunk->map[run_ind].bits & CHUNK_MAP_LARGE) != 0)
+		size = chunk->map[run_ind].bits & ~pagesize_mask;
+	else
+		size = run->bin->run_size;
+	run_pages = (size >> pagesize_2pow);
+
+	/* Mark pages as unallocated in the chunk map. */
+	if (dirty) {
+		size_t i;
+
+		for (i = 0; i < run_pages; i++) {
+			assert((chunk->map[run_ind + i].bits & CHUNK_MAP_DIRTY)
+			    == 0);
+			chunk->map[run_ind + i].bits = CHUNK_MAP_DIRTY;
+		}
+
+		if (chunk->ndirty == 0) {
+			arena_chunk_tree_dirty_insert(&arena->chunks_dirty,
+			    chunk);
+		}
+		chunk->ndirty += run_pages;
+		arena->ndirty += run_pages;
+	} else {
+		size_t i;
+
+		for (i = 0; i < run_pages; i++) {
+			chunk->map[run_ind + i].bits &= ~(CHUNK_MAP_LARGE |
+			    CHUNK_MAP_ALLOCATED);
+		}
+	}
+	chunk->map[run_ind].bits = size | (chunk->map[run_ind].bits &
+	    pagesize_mask);
+	chunk->map[run_ind+run_pages-1].bits = size |
+	    (chunk->map[run_ind+run_pages-1].bits & pagesize_mask);
+
+	/* Try to coalesce forward. */
+	if (run_ind + run_pages < chunk_npages &&
+	    (chunk->map[run_ind+run_pages].bits & CHUNK_MAP_ALLOCATED) == 0) {
+		size_t nrun_size = chunk->map[run_ind+run_pages].bits &
+		    ~pagesize_mask;
+
+		/*
+		 * Remove successor from runs_avail; the coalesced run is
+		 * inserted later.
+		 */
+		arena_avail_tree_remove(&arena->runs_avail,
+		    &chunk->map[run_ind+run_pages]);
+
+		size += nrun_size;
+		run_pages = size >> pagesize_2pow;
+
+		assert((chunk->map[run_ind+run_pages-1].bits & ~pagesize_mask)
+		    == nrun_size);
+		chunk->map[run_ind].bits = size | (chunk->map[run_ind].bits &
+		    pagesize_mask);
+		chunk->map[run_ind+run_pages-1].bits = size |
+		    (chunk->map[run_ind+run_pages-1].bits & pagesize_mask);
+	}
+
+	/* Try to coalesce backward. */
+	if (run_ind > arena_chunk_header_npages && (chunk->map[run_ind-1].bits &
+	    CHUNK_MAP_ALLOCATED) == 0) {
+		size_t prun_size = chunk->map[run_ind-1].bits & ~pagesize_mask;
+
+		run_ind -= prun_size >> pagesize_2pow;
+
+		/*
+		 * Remove predecessor from runs_avail; the coalesced run is
+		 * inserted later.
+		 */
+		arena_avail_tree_remove(&arena->runs_avail,
+		    &chunk->map[run_ind]);
+
+		size += prun_size;
+		run_pages = size >> pagesize_2pow;
+
+		assert((chunk->map[run_ind].bits & ~pagesize_mask) ==
+		    prun_size);
+		chunk->map[run_ind].bits = size | (chunk->map[run_ind].bits &
+		    pagesize_mask);
+		chunk->map[run_ind+run_pages-1].bits = size |
+		    (chunk->map[run_ind+run_pages-1].bits & pagesize_mask);
+	}
+
+	/* Insert into runs_avail, now that coalescing is complete. */
+	arena_avail_tree_insert(&arena->runs_avail, &chunk->map[run_ind]);
+
+	/* Deallocate chunk if it is now completely unused. */
+	if ((chunk->map[arena_chunk_header_npages].bits & (~pagesize_mask |
+	    CHUNK_MAP_ALLOCATED)) == arena_maxclass)
+		arena_chunk_dealloc(arena, chunk);
+
+	/* Enforce opt_dirty_max. */
+	if (arena->ndirty > opt_dirty_max)
+		arena_purge(arena);
+}
+
+static void
+arena_run_trim_head(arena_t *arena, arena_chunk_t *chunk, arena_run_t *run,
+    size_t oldsize, size_t newsize)
+{
+	size_t pageind = ((uintptr_t)run - (uintptr_t)chunk) >> pagesize_2pow;
+	size_t head_npages = (oldsize - newsize) >> pagesize_2pow;
+
+	assert(oldsize > newsize);
+
+	/*
+	 * Update the chunk map so that arena_run_dalloc() can treat the
+	 * leading run as separately allocated.
+	 */
+	chunk->map[pageind].bits = (oldsize - newsize) | CHUNK_MAP_LARGE |
+	    CHUNK_MAP_ALLOCATED;
+	chunk->map[pageind+head_npages].bits = newsize | CHUNK_MAP_LARGE |
+	    CHUNK_MAP_ALLOCATED;
+
+	arena_run_dalloc(arena, run, false);
+}
+
+static void
+arena_run_trim_tail(arena_t *arena, arena_chunk_t *chunk, arena_run_t *run,
+    size_t oldsize, size_t newsize, bool dirty)
+{
+	size_t pageind = ((uintptr_t)run - (uintptr_t)chunk) >> pagesize_2pow;
+	size_t npages = newsize >> pagesize_2pow;
+
+	assert(oldsize > newsize);
+
+	/*
+	 * Update the chunk map so that arena_run_dalloc() can treat the
+	 * trailing run as separately allocated.
+	 */
+	chunk->map[pageind].bits = newsize | CHUNK_MAP_LARGE |
+	    CHUNK_MAP_ALLOCATED;
+	chunk->map[pageind+npages].bits = (oldsize - newsize) | CHUNK_MAP_LARGE
+	    | CHUNK_MAP_ALLOCATED;
+
+	arena_run_dalloc(arena, (arena_run_t *)((uintptr_t)run + newsize),
+	    dirty);
+}
+
+static arena_run_t *
+arena_bin_nonfull_run_get(arena_t *arena, arena_bin_t *bin)
+{
+	arena_chunk_map_t *mapelm;
+	arena_run_t *run;
+	unsigned i, remainder;
+
+	/* Look for a usable run. */
+	mapelm = arena_run_tree_first(&bin->runs);
+	if (mapelm != NULL) {
+		/* run is guaranteed to have available space. */
+		arena_run_tree_remove(&bin->runs, mapelm);
+		run = (arena_run_t *)(mapelm->bits & ~pagesize_mask);
+#ifdef MALLOC_STATS
+		bin->stats.reruns++;
+#endif
+		return (run);
+	}
+	/* No existing runs have any space available. */
+
+	/* Allocate a new run. */
+	run = arena_run_alloc(arena, bin->run_size, false, false);
+	if (run == NULL)
+		return (NULL);
+
+	/* Initialize run internals. */
+	run->bin = bin;
+
+	for (i = 0; i < bin->regs_mask_nelms - 1; i++)
+		run->regs_mask[i] = UINT_MAX;
+	remainder = bin->nregs & ((1U << (SIZEOF_INT_2POW + 3)) - 1);
+	if (remainder == 0)
+		run->regs_mask[i] = UINT_MAX;
+	else {
+		/* The last element has spare bits that need to be unset. */
+		run->regs_mask[i] = (UINT_MAX >> ((1U << (SIZEOF_INT_2POW + 3))
+		    - remainder));
+	}
+
+	run->regs_minelm = 0;
+
+	run->nfree = bin->nregs;
+#ifdef MALLOC_DEBUG
+	run->magic = ARENA_RUN_MAGIC;
+#endif
+
+#ifdef MALLOC_STATS
+	bin->stats.nruns++;
+	bin->stats.curruns++;
+	if (bin->stats.curruns > bin->stats.highruns)
+		bin->stats.highruns = bin->stats.curruns;
+#endif
+	return (run);
+}
+
+/* bin->runcur must have space available before this function is called. */
+static inline void *
+arena_bin_malloc_easy(arena_t *arena, arena_bin_t *bin, arena_run_t *run)
+{
+	void *ret;
+
+	assert(run->magic == ARENA_RUN_MAGIC);
+	assert(run->nfree > 0);
+
+	ret = arena_run_reg_alloc(run, bin);
+	assert(ret != NULL);
+	run->nfree--;
+
+	return (ret);
+}
+
+/* Re-fill bin->runcur, then call arena_bin_malloc_easy(). */
+static void *
+arena_bin_malloc_hard(arena_t *arena, arena_bin_t *bin)
+{
+
+	bin->runcur = arena_bin_nonfull_run_get(arena, bin);
+	if (bin->runcur == NULL)
+		return (NULL);
+	assert(bin->runcur->magic == ARENA_RUN_MAGIC);
+	assert(bin->runcur->nfree > 0);
+
+	return (arena_bin_malloc_easy(arena, bin, bin->runcur));
+}
+
+/*
+ * Calculate bin->run_size such that it meets the following constraints:
+ *
+ *   *) bin->run_size >= min_run_size
+ *   *) bin->run_size <= arena_maxclass
+ *   *) bin->run_size <= RUN_MAX_SMALL
+ *   *) run header overhead <= RUN_MAX_OVRHD (or header overhead relaxed).
+ *
+ * bin->nregs, bin->regs_mask_nelms, and bin->reg0_offset are
+ * also calculated here, since these settings are all interdependent.
+ */
+static size_t
+arena_bin_run_size_calc(arena_bin_t *bin, size_t min_run_size)
+{
+	size_t try_run_size, good_run_size;
+	unsigned good_nregs, good_mask_nelms, good_reg0_offset;
+	unsigned try_nregs, try_mask_nelms, try_reg0_offset;
+
+	assert(min_run_size >= pagesize);
+	assert(min_run_size <= arena_maxclass);
+	assert(min_run_size <= RUN_MAX_SMALL);
+
+	/*
+	 * Calculate known-valid settings before entering the run_size
+	 * expansion loop, so that the first part of the loop always copies
+	 * valid settings.
+	 *
+	 * The do..while loop iteratively reduces the number of regions until
+	 * the run header and the regions no longer overlap.  A closed formula
+	 * would be quite messy, since there is an interdependency between the
+	 * header's mask length and the number of regions.
+	 */
+	try_run_size = min_run_size;
+	try_nregs = ((try_run_size - sizeof(arena_run_t)) / bin->reg_size)
+	    + 1; /* Counter-act try_nregs-- in loop. */
+	do {
+		try_nregs--;
+		try_mask_nelms = (try_nregs >> (SIZEOF_INT_2POW + 3)) +
+		    ((try_nregs & ((1U << (SIZEOF_INT_2POW + 3)) - 1)) ? 1 : 0);
+		try_reg0_offset = try_run_size - (try_nregs * bin->reg_size);
+	} while (sizeof(arena_run_t) + (sizeof(unsigned) * (try_mask_nelms - 1))
+	    > try_reg0_offset);
+
+	/* run_size expansion loop. */
+	do {
+		/*
+		 * Copy valid settings before trying more aggressive settings.
+		 */
+		good_run_size = try_run_size;
+		good_nregs = try_nregs;
+		good_mask_nelms = try_mask_nelms;
+		good_reg0_offset = try_reg0_offset;
+
+		/* Try more aggressive settings. */
+		try_run_size += pagesize;
+		try_nregs = ((try_run_size - sizeof(arena_run_t)) /
+		    bin->reg_size) + 1; /* Counter-act try_nregs-- in loop. */
+		do {
+			try_nregs--;
+			try_mask_nelms = (try_nregs >> (SIZEOF_INT_2POW + 3)) +
+			    ((try_nregs & ((1U << (SIZEOF_INT_2POW + 3)) - 1)) ?
+			    1 : 0);
+			try_reg0_offset = try_run_size - (try_nregs *
+			    bin->reg_size);
+		} while (sizeof(arena_run_t) + (sizeof(unsigned) *
+		    (try_mask_nelms - 1)) > try_reg0_offset);
+	} while (try_run_size <= arena_maxclass && try_run_size <= RUN_MAX_SMALL
+	    && RUN_MAX_OVRHD * (bin->reg_size << 3) > RUN_MAX_OVRHD_RELAX
+	    && (try_reg0_offset << RUN_BFP) > RUN_MAX_OVRHD * try_run_size);
+
+	assert(sizeof(arena_run_t) + (sizeof(unsigned) * (good_mask_nelms - 1))
+	    <= good_reg0_offset);
+	assert((good_mask_nelms << (SIZEOF_INT_2POW + 3)) >= good_nregs);
+
+	/* Copy final settings. */
+	bin->run_size = good_run_size;
+	bin->nregs = good_nregs;
+	bin->regs_mask_nelms = good_mask_nelms;
+	bin->reg0_offset = good_reg0_offset;
+
+	return (good_run_size);
+}
+
+#ifdef MALLOC_BALANCE
+static inline void
+arena_lock_balance(arena_t *arena)
+{
+	unsigned contention;
+
+	contention = malloc_spin_lock(&arena->lock);
+	if (narenas > 1) {
+		/*
+		 * Calculate the exponentially averaged contention for this
+		 * arena.  Due to integer math always rounding down, this value
+		 * decays somewhat faster than normal.
+		 */
+		arena->contention = (((uint64_t)arena->contention
+		    * (uint64_t)((1U << BALANCE_ALPHA_INV_2POW)-1))
+		    + (uint64_t)contention) >> BALANCE_ALPHA_INV_2POW;
+		if (arena->contention >= opt_balance_threshold)
+			arena_lock_balance_hard(arena);
+	}
+}
+
+static void
+arena_lock_balance_hard(arena_t *arena)
+{
+	uint32_t ind;
+
+	arena->contention = 0;
+#ifdef MALLOC_STATS
+	arena->stats.nbalance++;
+#endif
+	ind = PRN(balance, narenas_2pow);
+	if (arenas[ind] != NULL)
+		arenas_map = arenas[ind];
+	else {
+		malloc_spin_lock(&arenas_lock);
+		if (arenas[ind] != NULL)
+			arenas_map = arenas[ind];
+		else
+			arenas_map = arenas_extend(ind);
+		malloc_spin_unlock(&arenas_lock);
+	}
+}
+#endif
+
+#ifdef MALLOC_MAG
+static inline void *
+mag_alloc(mag_t *mag)
+{
+
+	if (mag->nrounds == 0)
+		return (NULL);
+	mag->nrounds--;
+
+	return (mag->rounds[mag->nrounds]);
+}
+
+static void
+mag_load(mag_t *mag)
+{
+	arena_t *arena;
+	arena_bin_t *bin;
+	arena_run_t *run;
+	void *round;
+	size_t i;
+
+	arena = choose_arena();
+	bin = &arena->bins[mag->binind];
+#ifdef MALLOC_BALANCE
+	arena_lock_balance(arena);
+#else
+	malloc_spin_lock(&arena->lock);
+#endif
+	for (i = mag->nrounds; i < max_rounds; i++) {
+		if ((run = bin->runcur) != NULL && run->nfree > 0)
+			round = arena_bin_malloc_easy(arena, bin, run);
+		else
+			round = arena_bin_malloc_hard(arena, bin);
+		if (round == NULL)
+			break;
+		mag->rounds[i] = round;
+	}
+#ifdef MALLOC_STATS
+	bin->stats.nmags++;
+	arena->stats.nmalloc_small += (i - mag->nrounds);
+	arena->stats.allocated_small += (i - mag->nrounds) * bin->reg_size;
+#endif
+	malloc_spin_unlock(&arena->lock);
+	mag->nrounds = i;
+}
+
+static inline void *
+mag_rack_alloc(mag_rack_t *rack, size_t size, bool zero)
+{
+	void *ret;
+	bin_mags_t *bin_mags;
+	mag_t *mag;
+	size_t binind;
+
+	binind = size2bin[size];
+	assert(binind < nbins);
+	bin_mags = &rack->bin_mags[binind];
+
+	mag = bin_mags->curmag;
+	if (mag == NULL) {
+		/* Create an initial magazine for this size class. */
+		assert(bin_mags->sparemag == NULL);
+		mag = mag_create(choose_arena(), binind);
+		if (mag == NULL)
+			return (NULL);
+		bin_mags->curmag = mag;
+		mag_load(mag);
+	}
+
+	ret = mag_alloc(mag);
+	if (ret == NULL) {
+		if (bin_mags->sparemag != NULL) {
+			if (bin_mags->sparemag->nrounds > 0) {
+				/* Swap magazines. */
+				bin_mags->curmag = bin_mags->sparemag;
+				bin_mags->sparemag = mag;
+				mag = bin_mags->curmag;
+			} else {
+				/* Reload the current magazine. */
+				mag_load(mag);
+			}
+		} else {
+			/* Create a second magazine. */
+			mag = mag_create(choose_arena(), binind);
+			if (mag == NULL)
+				return (NULL);
+			mag_load(mag);
+			bin_mags->sparemag = bin_mags->curmag;
+			bin_mags->curmag = mag;
+		}
+		ret = mag_alloc(mag);
+		if (ret == NULL)
+			return (NULL);
+	}
+
+	if (zero == false) {
+		if (opt_junk)
+			memset(ret, 0xa5, size);
+		else if (opt_zero)
+			memset(ret, 0, size);
+	} else
+		memset(ret, 0, size);
+
+	return (ret);
+}
+#endif
+
+static inline void *
+arena_malloc_small(arena_t *arena, size_t size, bool zero)
+{
+	void *ret;
+	arena_bin_t *bin;
+	arena_run_t *run;
+	size_t binind;
+
+	binind = size2bin[size];
+	assert(binind < nbins);
+	bin = &arena->bins[binind];
+	size = bin->reg_size;
+
+#ifdef MALLOC_BALANCE
+	arena_lock_balance(arena);
+#else
+	malloc_spin_lock(&arena->lock);
+#endif
+	if ((run = bin->runcur) != NULL && run->nfree > 0)
+		ret = arena_bin_malloc_easy(arena, bin, run);
+	else
+		ret = arena_bin_malloc_hard(arena, bin);
+
+	if (ret == NULL) {
+		malloc_spin_unlock(&arena->lock);
+		return (NULL);
+	}
+
+#ifdef MALLOC_STATS
+	bin->stats.nrequests++;
+	arena->stats.nmalloc_small++;
+	arena->stats.allocated_small += size;
+#endif
+	malloc_spin_unlock(&arena->lock);
+
+	if (zero == false) {
+		if (opt_junk)
+			memset(ret, 0xa5, size);
+		else if (opt_zero)
+			memset(ret, 0, size);
+	} else
+		memset(ret, 0, size);
+
+	return (ret);
+}
+
+static void *
+arena_malloc_large(arena_t *arena, size_t size, bool zero)
+{
+	void *ret;
+
+	/* Large allocation. */
+	size = PAGE_CEILING(size);
+#ifdef MALLOC_BALANCE
+	arena_lock_balance(arena);
+#else
+	malloc_spin_lock(&arena->lock);
+#endif
+	ret = (void *)arena_run_alloc(arena, size, true, zero);
+	if (ret == NULL) {
+		malloc_spin_unlock(&arena->lock);
+		return (NULL);
+	}
+#ifdef MALLOC_STATS
+	arena->stats.nmalloc_large++;
+	arena->stats.allocated_large += size;
+#endif
+	malloc_spin_unlock(&arena->lock);
+
+	if (zero == false) {
+		if (opt_junk)
+			memset(ret, 0xa5, size);
+		else if (opt_zero)
+			memset(ret, 0, size);
+	}
+
+	return (ret);
+}
+
+static inline void *
+arena_malloc(arena_t *arena, size_t size, bool zero)
+{
+
+	assert(arena != NULL);
+	assert(arena->magic == ARENA_MAGIC);
+	assert(size != 0);
+	assert(QUANTUM_CEILING(size) <= arena_maxclass);
+
+	if (size <= bin_maxclass) {
+#ifdef MALLOC_MAG
+		if (__isthreaded && opt_mag) {
+			mag_rack_t *rack = mag_rack;
+			if (rack == NULL) {
+				rack = mag_rack_create(arena);
+				if (rack == NULL)
+					return (NULL);
+				mag_rack = rack;
+			}
+			return (mag_rack_alloc(rack, size, zero));
+		} else
+#endif
+			return (arena_malloc_small(arena, size, zero));
+	} else
+		return (arena_malloc_large(arena, size, zero));
+}
+
+static inline void *
+imalloc(size_t size)
+{
+
+	assert(size != 0);
+
+	if (size <= arena_maxclass)
+		return (arena_malloc(choose_arena(), size, false));
+	else
+		return (huge_malloc(size, false));
+}
+
+static inline void *
+icalloc(size_t size)
+{
+
+	if (size <= arena_maxclass)
+		return (arena_malloc(choose_arena(), size, true));
+	else
+		return (huge_malloc(size, true));
+}
+
+/* Only handles large allocations that require more than page alignment. */
+static void *
+arena_palloc(arena_t *arena, size_t alignment, size_t size, size_t alloc_size)
+{
+	void *ret;
+	size_t offset;
+	arena_chunk_t *chunk;
+
+	assert((size & pagesize_mask) == 0);
+	assert((alignment & pagesize_mask) == 0);
+
+#ifdef MALLOC_BALANCE
+	arena_lock_balance(arena);
+#else
+	malloc_spin_lock(&arena->lock);
+#endif
+	ret = (void *)arena_run_alloc(arena, alloc_size, true, false);
+	if (ret == NULL) {
+		malloc_spin_unlock(&arena->lock);
+		return (NULL);
+	}
+
+	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ret);
+
+	offset = (uintptr_t)ret & (alignment - 1);
+	assert((offset & pagesize_mask) == 0);
+	assert(offset < alloc_size);
+	if (offset == 0)
+		arena_run_trim_tail(arena, chunk, ret, alloc_size, size, false);
+	else {
+		size_t leadsize, trailsize;
+
+		leadsize = alignment - offset;
+		if (leadsize > 0) {
+			arena_run_trim_head(arena, chunk, ret, alloc_size,
+			    alloc_size - leadsize);
+			ret = (void *)((uintptr_t)ret + leadsize);
+		}
+
+		trailsize = alloc_size - leadsize - size;
+		if (trailsize != 0) {
+			/* Trim trailing space. */
+			assert(trailsize < alloc_size);
+			arena_run_trim_tail(arena, chunk, ret, size + trailsize,
+			    size, false);
+		}
+	}
+
+#ifdef MALLOC_STATS
+	arena->stats.nmalloc_large++;
+	arena->stats.allocated_large += size;
+#endif
+	malloc_spin_unlock(&arena->lock);
+
+	if (opt_junk)
+		memset(ret, 0xa5, size);
+	else if (opt_zero)
+		memset(ret, 0, size);
+	return (ret);
+}
+
+static inline void *
+ipalloc(size_t alignment, size_t size)
+{
+	void *ret;
+	size_t ceil_size;
+
+	/*
+	 * Round size up to the nearest multiple of alignment.
+	 *
+	 * This done, we can take advantage of the fact that for each small
+	 * size class, every object is aligned at the smallest power of two
+	 * that is non-zero in the base two representation of the size.  For
+	 * example:
+	 *
+	 *   Size |   Base 2 | Minimum alignment
+	 *   -----+----------+------------------
+	 *     96 |  1100000 |  32
+	 *    144 | 10100000 |  32
+	 *    192 | 11000000 |  64
+	 *
+	 * Depending on runtime settings, it is possible that arena_malloc()
+	 * will further round up to a power of two, but that never causes
+	 * correctness issues.
+	 */
+	ceil_size = (size + (alignment - 1)) & (-alignment);
+	/*
+	 * (ceil_size < size) protects against the combination of maximal
+	 * alignment and size greater than maximal alignment.
+	 */
+	if (ceil_size < size) {
+		/* size_t overflow. */
+		return (NULL);
+	}
+
+	if (ceil_size <= pagesize || (alignment <= pagesize
+	    && ceil_size <= arena_maxclass))
+		ret = arena_malloc(choose_arena(), ceil_size, false);
+	else {
+		size_t run_size;
+
+		/*
+		 * We can't achieve subpage alignment, so round up alignment
+		 * permanently; it makes later calculations simpler.
+		 */
+		alignment = PAGE_CEILING(alignment);
+		ceil_size = PAGE_CEILING(size);
+		/*
+		 * (ceil_size < size) protects against very large sizes within
+		 * pagesize of SIZE_T_MAX.
+		 *
+		 * (ceil_size + alignment < ceil_size) protects against the
+		 * combination of maximal alignment and ceil_size large enough
+		 * to cause overflow.  This is similar to the first overflow
+		 * check above, but it needs to be repeated due to the new
+		 * ceil_size value, which may now be *equal* to maximal
+		 * alignment, whereas before we only detected overflow if the
+		 * original size was *greater* than maximal alignment.
+		 */
+		if (ceil_size < size || ceil_size + alignment < ceil_size) {
+			/* size_t overflow. */
+			return (NULL);
+		}
+
+		/*
+		 * Calculate the size of the over-size run that arena_palloc()
+		 * would need to allocate in order to guarantee the alignment.
+		 */
+		if (ceil_size >= alignment)
+			run_size = ceil_size + alignment - pagesize;
+		else {
+			/*
+			 * It is possible that (alignment << 1) will cause
+			 * overflow, but it doesn't matter because we also
+			 * subtract pagesize, which in the case of overflow
+			 * leaves us with a very large run_size.  That causes
+			 * the first conditional below to fail, which means
+			 * that the bogus run_size value never gets used for
+			 * anything important.
+			 */
+			run_size = (alignment << 1) - pagesize;
+		}
+
+		if (run_size <= arena_maxclass) {
+			ret = arena_palloc(choose_arena(), alignment, ceil_size,
+			    run_size);
+		} else if (alignment <= chunksize)
+			ret = huge_malloc(ceil_size, false);
+		else
+			ret = huge_palloc(alignment, ceil_size);
+	}
+
+	assert(((uintptr_t)ret & (alignment - 1)) == 0);
+	return (ret);
+}
+
+/* Return the size of the allocation pointed to by ptr. */
+static size_t
+arena_salloc(const void *ptr)
+{
+	size_t ret;
+	arena_chunk_t *chunk;
+	size_t pageind, mapbits;
+
+	assert(ptr != NULL);
+	assert(CHUNK_ADDR2BASE(ptr) != ptr);
+
+	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
+	pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow);
+	mapbits = chunk->map[pageind].bits;
+	assert((mapbits & CHUNK_MAP_ALLOCATED) != 0);
+	if ((mapbits & CHUNK_MAP_LARGE) == 0) {
+		arena_run_t *run = (arena_run_t *)(mapbits & ~pagesize_mask);
+		assert(run->magic == ARENA_RUN_MAGIC);
+		ret = run->bin->reg_size;
+	} else {
+		ret = mapbits & ~pagesize_mask;
+		assert(ret != 0);
+	}
+
+	return (ret);
+}
+
+static inline size_t
+isalloc(const void *ptr)
+{
+	size_t ret;
+	arena_chunk_t *chunk;
+
+	assert(ptr != NULL);
+
+	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
+	if (chunk != ptr) {
+		/* Region. */
+		assert(chunk->arena->magic == ARENA_MAGIC);
+
+		ret = arena_salloc(ptr);
+	} else {
+		extent_node_t *node, key;
+
+		/* Chunk (huge allocation). */
+
+		malloc_mutex_lock(&huge_mtx);
+
+		/* Extract from tree of huge allocations. */
+		key.addr = __DECONST(void *, ptr);
+		node = extent_tree_ad_search(&huge, &key);
+		assert(node != NULL);
+
+		ret = node->size;
+
+		malloc_mutex_unlock(&huge_mtx);
+	}
+
+	return (ret);
+}
+
+static inline void
+arena_dalloc_small(arena_t *arena, arena_chunk_t *chunk, void *ptr,
+    arena_chunk_map_t *mapelm)
+{
+	arena_run_t *run;
+	arena_bin_t *bin;
+	size_t size;
+
+	run = (arena_run_t *)(mapelm->bits & ~pagesize_mask);
+	assert(run->magic == ARENA_RUN_MAGIC);
+	bin = run->bin;
+	size = bin->reg_size;
+
+	if (opt_junk)
+		memset(ptr, 0x5a, size);
+
+	arena_run_reg_dalloc(run, bin, ptr, size);
+	run->nfree++;
+
+	if (run->nfree == bin->nregs) {
+		/* Deallocate run. */
+		if (run == bin->runcur)
+			bin->runcur = NULL;
+		else if (bin->nregs != 1) {
+			size_t run_pageind = (((uintptr_t)run -
+			    (uintptr_t)chunk)) >> pagesize_2pow;
+			arena_chunk_map_t *run_mapelm =
+			    &chunk->map[run_pageind];
+			/*
+			 * This block's conditional is necessary because if the
+			 * run only contains one region, then it never gets
+			 * inserted into the non-full runs tree.
+			 */
+			arena_run_tree_remove(&bin->runs, run_mapelm);
+		}
+#ifdef MALLOC_DEBUG
+		run->magic = 0;
+#endif
+		arena_run_dalloc(arena, run, true);
+#ifdef MALLOC_STATS
+		bin->stats.curruns--;
+#endif
+	} else if (run->nfree == 1 && run != bin->runcur) {
+		/*
+		 * Make sure that bin->runcur always refers to the lowest
+		 * non-full run, if one exists.
+		 */
+		if (bin->runcur == NULL)
+			bin->runcur = run;
+		else if ((uintptr_t)run < (uintptr_t)bin->runcur) {
+			/* Switch runcur. */
+			if (bin->runcur->nfree > 0) {
+				arena_chunk_t *runcur_chunk =
+				    CHUNK_ADDR2BASE(bin->runcur);
+				size_t runcur_pageind =
+				    (((uintptr_t)bin->runcur -
+				    (uintptr_t)runcur_chunk)) >> pagesize_2pow;
+				arena_chunk_map_t *runcur_mapelm =
+				    &runcur_chunk->map[runcur_pageind];
+
+				/* Insert runcur. */
+				arena_run_tree_insert(&bin->runs,
+				    runcur_mapelm);
+			}
+			bin->runcur = run;
+		} else {
+			size_t run_pageind = (((uintptr_t)run -
+			    (uintptr_t)chunk)) >> pagesize_2pow;
+			arena_chunk_map_t *run_mapelm =
+			    &chunk->map[run_pageind];
+
+			assert(arena_run_tree_search(&bin->runs, run_mapelm) ==
+			    NULL);
+			arena_run_tree_insert(&bin->runs, run_mapelm);
+		}
+	}
+#ifdef MALLOC_STATS
+	arena->stats.allocated_small -= size;
+	arena->stats.ndalloc_small++;
+#endif
+}
+
+#ifdef MALLOC_MAG
+static void
+mag_unload(mag_t *mag)
+{
+	arena_chunk_t *chunk;
+	arena_t *arena;
+	void *round;
+	size_t i, ndeferred, nrounds;
+
+	for (ndeferred = mag->nrounds; ndeferred > 0;) {
+		nrounds = ndeferred;
+		/* Lock the arena associated with the first round. */
+		chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(mag->rounds[0]);
+		arena = chunk->arena;
+#ifdef MALLOC_BALANCE
+		arena_lock_balance(arena);
+#else
+		malloc_spin_lock(&arena->lock);
+#endif
+		/* Deallocate every round that belongs to the locked arena. */
+		for (i = ndeferred = 0; i < nrounds; i++) {
+			round = mag->rounds[i];
+			chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(round);
+			if (chunk->arena == arena) {
+				size_t pageind = (((uintptr_t)round -
+				    (uintptr_t)chunk) >> pagesize_2pow);
+				arena_chunk_map_t *mapelm =
+				    &chunk->map[pageind];
+				arena_dalloc_small(arena, chunk, round, mapelm);
+			} else {
+				/*
+				 * This round was allocated via a different
+				 * arena than the one that is currently locked.
+				 * Stash the round, so that it can be handled
+				 * in a future pass.
+				 */
+				mag->rounds[ndeferred] = round;
+				ndeferred++;
+			}
+		}
+		malloc_spin_unlock(&arena->lock);
+	}
+
+	mag->nrounds = 0;
+}
+
+static inline void
+mag_rack_dalloc(mag_rack_t *rack, void *ptr)
+{
+	arena_t *arena;
+	arena_chunk_t *chunk;
+	arena_run_t *run;
+	arena_bin_t *bin;
+	bin_mags_t *bin_mags;
+	mag_t *mag;
+	size_t pageind, binind;
+	arena_chunk_map_t *mapelm;
+
+	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
+	arena = chunk->arena;
+	pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow);
+	mapelm = &chunk->map[pageind];
+	run = (arena_run_t *)(mapelm->bits & ~pagesize_mask);
+	assert(run->magic == ARENA_RUN_MAGIC);
+	bin = run->bin;
+	binind = ((uintptr_t)bin - (uintptr_t)&arena->bins) /
+	    sizeof(arena_bin_t);
+	assert(binind < nbins);
+
+	if (opt_junk)
+		memset(ptr, 0x5a, arena->bins[binind].reg_size);
+
+	bin_mags = &rack->bin_mags[binind];
+	mag = bin_mags->curmag;
+	if (mag == NULL) {
+		/* Create an initial magazine for this size class. */
+		assert(bin_mags->sparemag == NULL);
+		mag = mag_create(choose_arena(), binind);
+		if (mag == NULL) {
+			malloc_spin_lock(&arena->lock);
+			arena_dalloc_small(arena, chunk, ptr, mapelm);
+			malloc_spin_unlock(&arena->lock);
+			return;
+		}
+		bin_mags->curmag = mag;
+	}
+
+	if (mag->nrounds == max_rounds) {
+		if (bin_mags->sparemag != NULL) {
+			if (bin_mags->sparemag->nrounds < max_rounds) {
+				/* Swap magazines. */
+				bin_mags->curmag = bin_mags->sparemag;
+				bin_mags->sparemag = mag;
+				mag = bin_mags->curmag;
+			} else {
+				/* Unload the current magazine. */
+				mag_unload(mag);
+			}
+		} else {
+			/* Create a second magazine. */
+			mag = mag_create(choose_arena(), binind);
+			if (mag == NULL) {
+				mag = rack->bin_mags[binind].curmag;
+				mag_unload(mag);
+			} else {
+				bin_mags->sparemag = bin_mags->curmag;
+				bin_mags->curmag = mag;
+			}
+		}
+		assert(mag->nrounds < max_rounds);
+	}
+	mag->rounds[mag->nrounds] = ptr;
+	mag->nrounds++;
+}
+#endif
+
+static void
+arena_dalloc_large(arena_t *arena, arena_chunk_t *chunk, void *ptr)
+{
+	/* Large allocation. */
+	malloc_spin_lock(&arena->lock);
+
+#ifndef MALLOC_STATS
+	if (opt_junk)
+#endif
+	{
+		size_t pageind = ((uintptr_t)ptr - (uintptr_t)chunk) >>
+		    pagesize_2pow;
+		size_t size = chunk->map[pageind].bits & ~pagesize_mask;
+
+#ifdef MALLOC_STATS
+		if (opt_junk)
+#endif
+			memset(ptr, 0x5a, size);
+#ifdef MALLOC_STATS
+		arena->stats.allocated_large -= size;
+#endif
+	}
+#ifdef MALLOC_STATS
+	arena->stats.ndalloc_large++;
+#endif
+
+	arena_run_dalloc(arena, (arena_run_t *)ptr, true);
+	malloc_spin_unlock(&arena->lock);
+}
+
+static inline void
+arena_dalloc(arena_t *arena, arena_chunk_t *chunk, void *ptr)
+{
+	size_t pageind;
+	arena_chunk_map_t *mapelm;
+
+	assert(arena != NULL);
+	assert(arena->magic == ARENA_MAGIC);
+	assert(chunk->arena == arena);
+	assert(ptr != NULL);
+	assert(CHUNK_ADDR2BASE(ptr) != ptr);
+
+	pageind = (((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow);
+	mapelm = &chunk->map[pageind];
+	assert((mapelm->bits & CHUNK_MAP_ALLOCATED) != 0);
+	if ((mapelm->bits & CHUNK_MAP_LARGE) == 0) {
+		/* Small allocation. */
+#ifdef MALLOC_MAG
+		if (__isthreaded && opt_mag) {
+			mag_rack_t *rack = mag_rack;
+			if (rack == NULL) {
+				rack = mag_rack_create(arena);
+				if (rack == NULL) {
+					malloc_spin_lock(&arena->lock);
+					arena_dalloc_small(arena, chunk, ptr,
+					    mapelm);
+					malloc_spin_unlock(&arena->lock);
+				}
+				mag_rack = rack;
+			}
+			mag_rack_dalloc(rack, ptr);
+		} else {
+#endif
+			malloc_spin_lock(&arena->lock);
+			arena_dalloc_small(arena, chunk, ptr, mapelm);
+			malloc_spin_unlock(&arena->lock);
+#ifdef MALLOC_MAG
+		}
+#endif
+	} else
+		arena_dalloc_large(arena, chunk, ptr);
+}
+
+static inline void
+idalloc(void *ptr)
+{
+	arena_chunk_t *chunk;
+
+	assert(ptr != NULL);
+
+	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
+	if (chunk != ptr)
+		arena_dalloc(chunk->arena, chunk, ptr);
+	else
+		huge_dalloc(ptr);
+}
+
+static void
+arena_ralloc_large_shrink(arena_t *arena, arena_chunk_t *chunk, void *ptr,
+    size_t size, size_t oldsize)
+{
+
+	assert(size < oldsize);
+
+	/*
+	 * Shrink the run, and make trailing pages available for other
+	 * allocations.
+	 */
+#ifdef MALLOC_BALANCE
+	arena_lock_balance(arena);
+#else
+	malloc_spin_lock(&arena->lock);
+#endif
+	arena_run_trim_tail(arena, chunk, (arena_run_t *)ptr, oldsize, size,
+	    true);
+#ifdef MALLOC_STATS
+	arena->stats.allocated_large -= oldsize - size;
+#endif
+	malloc_spin_unlock(&arena->lock);
+}
+
+static bool
+arena_ralloc_large_grow(arena_t *arena, arena_chunk_t *chunk, void *ptr,
+    size_t size, size_t oldsize)
+{
+	size_t pageind = ((uintptr_t)ptr - (uintptr_t)chunk) >> pagesize_2pow;
+	size_t npages = oldsize >> pagesize_2pow;
+
+	assert(oldsize == (chunk->map[pageind].bits & ~pagesize_mask));
+
+	/* Try to extend the run. */
+	assert(size > oldsize);
+#ifdef MALLOC_BALANCE
+	arena_lock_balance(arena);
+#else
+	malloc_spin_lock(&arena->lock);
+#endif
+	if (pageind + npages < chunk_npages && (chunk->map[pageind+npages].bits
+	    & CHUNK_MAP_ALLOCATED) == 0 && (chunk->map[pageind+npages].bits &
+	    ~pagesize_mask) >= size - oldsize) {
+		/*
+		 * The next run is available and sufficiently large.  Split the
+		 * following run, then merge the first part with the existing
+		 * allocation.
+		 */
+		arena_run_split(arena, (arena_run_t *)((uintptr_t)chunk +
+		    ((pageind+npages) << pagesize_2pow)), size - oldsize, true,
+		    false);
+
+		chunk->map[pageind].bits = size | CHUNK_MAP_LARGE |
+		    CHUNK_MAP_ALLOCATED;
+		chunk->map[pageind+npages].bits = CHUNK_MAP_LARGE |
+		    CHUNK_MAP_ALLOCATED;
+
+#ifdef MALLOC_STATS
+		arena->stats.allocated_large += size - oldsize;
+#endif
+		malloc_spin_unlock(&arena->lock);
+		return (false);
+	}
+	malloc_spin_unlock(&arena->lock);
+
+	return (true);
+}
+
+/*
+ * Try to resize a large allocation, in order to avoid copying.  This will
+ * always fail if growing an object, and the following run is already in use.
+ */
+static bool
+arena_ralloc_large(void *ptr, size_t size, size_t oldsize)
+{
+	size_t psize;
+
+	psize = PAGE_CEILING(size);
+	if (psize == oldsize) {
+		/* Same size class. */
+		if (opt_junk && size < oldsize) {
+			memset((void *)((uintptr_t)ptr + size), 0x5a, oldsize -
+			    size);
+		}
+		return (false);
+	} else {
+		arena_chunk_t *chunk;
+		arena_t *arena;
+
+		chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
+		arena = chunk->arena;
+		assert(arena->magic == ARENA_MAGIC);
+
+		if (psize < oldsize) {
+			/* Fill before shrinking in order avoid a race. */
+			if (opt_junk) {
+				memset((void *)((uintptr_t)ptr + size), 0x5a,
+				    oldsize - size);
+			}
+			arena_ralloc_large_shrink(arena, chunk, ptr, psize,
+			    oldsize);
+			return (false);
+		} else {
+			bool ret = arena_ralloc_large_grow(arena, chunk, ptr,
+			    psize, oldsize);
+			if (ret == false && opt_zero) {
+				memset((void *)((uintptr_t)ptr + oldsize), 0,
+				    size - oldsize);
+			}
+			return (ret);
+		}
+	}
+}
+
+static void *
+arena_ralloc(void *ptr, size_t size, size_t oldsize)
+{
+	void *ret;
+	size_t copysize;
+
+	/* Try to avoid moving the allocation. */
+	if (size <= bin_maxclass) {
+		if (oldsize <= bin_maxclass && size2bin[size] ==
+		    size2bin[oldsize])
+			goto IN_PLACE;
+	} else {
+		if (oldsize > bin_maxclass && oldsize <= arena_maxclass) {
+			assert(size > bin_maxclass);
+			if (arena_ralloc_large(ptr, size, oldsize) == false)
+				return (ptr);
+		}
+	}
+
+	/*
+	 * If we get here, then size and oldsize are different enough that we
+	 * need to move the object.  In that case, fall back to allocating new
+	 * space and copying.
+	 */
+	ret = arena_malloc(choose_arena(), size, false);
+	if (ret == NULL)
+		return (NULL);
+
+	/* Junk/zero-filling were already done by arena_malloc(). */
+	copysize = (size < oldsize) ? size : oldsize;
+	memcpy(ret, ptr, copysize);
+	idalloc(ptr);
+	return (ret);
+IN_PLACE:
+	if (opt_junk && size < oldsize)
+		memset((void *)((uintptr_t)ptr + size), 0x5a, oldsize - size);
+	else if (opt_zero && size > oldsize)
+		memset((void *)((uintptr_t)ptr + oldsize), 0, size - oldsize);
+	return (ptr);
+}
+
+static inline void *
+iralloc(void *ptr, size_t size)
+{
+	size_t oldsize;
+
+	assert(ptr != NULL);
+	assert(size != 0);
+
+	oldsize = isalloc(ptr);
+
+	if (size <= arena_maxclass)
+		return (arena_ralloc(ptr, size, oldsize));
+	else
+		return (huge_ralloc(ptr, size, oldsize));
+}
+
+static bool
+arena_new(arena_t *arena)
+{
+	unsigned i;
+	arena_bin_t *bin;
+	size_t prev_run_size;
+
+	if (malloc_spin_init(&arena->lock))
+		return (true);
+
+#ifdef MALLOC_STATS
+	memset(&arena->stats, 0, sizeof(arena_stats_t));
+#endif
+
+	/* Initialize chunks. */
+	arena_chunk_tree_dirty_new(&arena->chunks_dirty);
+	arena->spare = NULL;
+
+	arena->ndirty = 0;
+
+	arena_avail_tree_new(&arena->runs_avail);
+
+#ifdef MALLOC_BALANCE
+	arena->contention = 0;
+#endif
+
+	/* Initialize bins. */
+	prev_run_size = pagesize;
+
+	i = 0;
+#ifdef MALLOC_TINY
+	/* (2^n)-spaced tiny bins. */
+	for (; i < ntbins; i++) {
+		bin = &arena->bins[i];
+		bin->runcur = NULL;
+		arena_run_tree_new(&bin->runs);
+
+		bin->reg_size = (1U << (TINY_MIN_2POW + i));
+
+		prev_run_size = arena_bin_run_size_calc(bin, prev_run_size);
+
+#ifdef MALLOC_STATS
+		memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
+#endif
+	}
+#endif
+
+	/* Quantum-spaced bins. */
+	for (; i < ntbins + nqbins; i++) {
+		bin = &arena->bins[i];
+		bin->runcur = NULL;
+		arena_run_tree_new(&bin->runs);
+
+		bin->reg_size = (i - ntbins + 1) << QUANTUM_2POW;
+
+		prev_run_size = arena_bin_run_size_calc(bin, prev_run_size);
+
+#ifdef MALLOC_STATS
+		memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
+#endif
+	}
+
+	/* Cacheline-spaced bins. */
+	for (; i < ntbins + nqbins + ncbins; i++) {
+		bin = &arena->bins[i];
+		bin->runcur = NULL;
+		arena_run_tree_new(&bin->runs);
+
+		bin->reg_size = cspace_min + ((i - (ntbins + nqbins)) <<
+		    CACHELINE_2POW);
+
+		prev_run_size = arena_bin_run_size_calc(bin, prev_run_size);
+
+#ifdef MALLOC_STATS
+		memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
+#endif
+	}
+
+	/* Subpage-spaced bins. */
+	for (; i < nbins; i++) {
+		bin = &arena->bins[i];
+		bin->runcur = NULL;
+		arena_run_tree_new(&bin->runs);
+
+		bin->reg_size = sspace_min + ((i - (ntbins + nqbins + ncbins))
+		    << SUBPAGE_2POW);
+
+		prev_run_size = arena_bin_run_size_calc(bin, prev_run_size);
+
+#ifdef MALLOC_STATS
+		memset(&bin->stats, 0, sizeof(malloc_bin_stats_t));
+#endif
+	}
+
+#ifdef MALLOC_DEBUG
+	arena->magic = ARENA_MAGIC;
+#endif
+
+	return (false);
+}
+
+/* Create a new arena and insert it into the arenas array at index ind. */
+static arena_t *
+arenas_extend(unsigned ind)
+{
+	arena_t *ret;
+
+	/* Allocate enough space for trailing bins. */
+	ret = (arena_t *)base_alloc(sizeof(arena_t)
+	    + (sizeof(arena_bin_t) * (nbins - 1)));
+	if (ret != NULL && arena_new(ret) == false) {
+		arenas[ind] = ret;
+		return (ret);
+	}
+	/* Only reached if there is an OOM error. */
+
+	/*
+	 * OOM here is quite inconvenient to propagate, since dealing with it
+	 * would require a check for failure in the fast path.  Instead, punt
+	 * by using arenas[0].  In practice, this is an extremely unlikely
+	 * failure.
+	 */
+	_malloc_message(_getprogname(),
+	    ": (malloc) Error initializing arena\n", "", "");
+	if (opt_abort)
+		abort();
+
+	return (arenas[0]);
+}
+
+#ifdef MALLOC_MAG
+static mag_t *
+mag_create(arena_t *arena, size_t binind)
+{
+	mag_t *ret;
+
+	if (sizeof(mag_t) + (sizeof(void *) * (max_rounds - 1)) <=
+	    bin_maxclass) {
+		ret = arena_malloc_small(arena, sizeof(mag_t) + (sizeof(void *)
+		    * (max_rounds - 1)), false);
+	} else {
+		ret = imalloc(sizeof(mag_t) + (sizeof(void *) * (max_rounds -
+		    1)));
+	}
+	if (ret == NULL)
+		return (NULL);
+	ret->binind = binind;
+	ret->nrounds = 0;
+
+	return (ret);
+}
+
+static void
+mag_destroy(mag_t *mag)
+{
+	arena_t *arena;
+	arena_chunk_t *chunk;
+	size_t pageind;
+	arena_chunk_map_t *mapelm;
+
+	chunk = CHUNK_ADDR2BASE(mag);
+	arena = chunk->arena;
+	pageind = (((uintptr_t)mag - (uintptr_t)chunk) >> pagesize_2pow);
+	mapelm = &chunk->map[pageind];
+
+	assert(mag->nrounds == 0);
+	if (sizeof(mag_t) + (sizeof(void *) * (max_rounds - 1)) <=
+	    bin_maxclass) {
+		malloc_spin_lock(&arena->lock);
+		arena_dalloc_small(arena, chunk, mag, mapelm);
+		malloc_spin_unlock(&arena->lock);
+	} else
+		idalloc(mag);
+}
+
+static mag_rack_t *
+mag_rack_create(arena_t *arena)
+{
+
+	assert(sizeof(mag_rack_t) + (sizeof(bin_mags_t *) * (nbins - 1)) <=
+	    bin_maxclass);
+	return (arena_malloc_small(arena, sizeof(mag_rack_t) +
+	    (sizeof(bin_mags_t) * (nbins - 1)), true));
+}
+
+static void
+mag_rack_destroy(mag_rack_t *rack)
+{
+	arena_t *arena;
+	arena_chunk_t *chunk;
+	bin_mags_t *bin_mags;
+	size_t i, pageind;
+	arena_chunk_map_t *mapelm;
+
+	for (i = 0; i < nbins; i++) {
+		bin_mags = &rack->bin_mags[i];
+		if (bin_mags->curmag != NULL) {
+			assert(bin_mags->curmag->binind == i);
+			mag_unload(bin_mags->curmag);
+			mag_destroy(bin_mags->curmag);
+		}
+		if (bin_mags->sparemag != NULL) {
+			assert(bin_mags->sparemag->binind == i);
+			mag_unload(bin_mags->sparemag);
+			mag_destroy(bin_mags->sparemag);
+		}
+	}
+
+	chunk = CHUNK_ADDR2BASE(rack);
+	arena = chunk->arena;
+	pageind = (((uintptr_t)rack - (uintptr_t)chunk) >> pagesize_2pow);
+	mapelm = &chunk->map[pageind];
+
+	malloc_spin_lock(&arena->lock);
+	arena_dalloc_small(arena, chunk, rack, mapelm);
+	malloc_spin_unlock(&arena->lock);
+}
+#endif
+
+/*
+ * End arena.
+ */
+/******************************************************************************/
+/*
+ * Begin general internal functions.
+ */
+
+static void *
+huge_malloc(size_t size, bool zero)
+{
+	void *ret;
+	size_t csize;
+	extent_node_t *node;
+
+	/* Allocate one or more contiguous chunks for this request. */
+
+	csize = CHUNK_CEILING(size);
+	if (csize == 0) {
+		/* size is large enough to cause size_t wrap-around. */
+		return (NULL);
+	}
+
+	/* Allocate an extent node with which to track the chunk. */
+	node = base_node_alloc();
+	if (node == NULL)
+		return (NULL);
+
+	ret = chunk_alloc(csize, zero);
+	if (ret == NULL) {
+		base_node_dealloc(node);
+		return (NULL);
+	}
+
+	/* Insert node into huge. */
+	node->addr = ret;
+	node->size = csize;
+
+	malloc_mutex_lock(&huge_mtx);
+	extent_tree_ad_insert(&huge, node);
+#ifdef MALLOC_STATS
+	huge_nmalloc++;
+	huge_allocated += csize;
+#endif
+	malloc_mutex_unlock(&huge_mtx);
+
+	if (zero == false) {
+		if (opt_junk)
+			memset(ret, 0xa5, csize);
+		else if (opt_zero)
+			memset(ret, 0, csize);
+	}
+
+	return (ret);
+}
+
+/* Only handles large allocations that require more than chunk alignment. */
+static void *
+huge_palloc(size_t alignment, size_t size)
+{
+	void *ret;
+	size_t alloc_size, chunk_size, offset;
+	extent_node_t *node;
+
+	/*
+	 * This allocation requires alignment that is even larger than chunk
+	 * alignment.  This means that huge_malloc() isn't good enough.
+	 *
+	 * Allocate almost twice as many chunks as are demanded by the size or
+	 * alignment, in order to assure the alignment can be achieved, then
+	 * unmap leading and trailing chunks.
+	 */
+	assert(alignment >= chunksize);
+
+	chunk_size = CHUNK_CEILING(size);
+
+	if (size >= alignment)
+		alloc_size = chunk_size + alignment - chunksize;
+	else
+		alloc_size = (alignment << 1) - chunksize;
+
+	/* Allocate an extent node with which to track the chunk. */
+	node = base_node_alloc();
+	if (node == NULL)
+		return (NULL);
+
+	ret = chunk_alloc(alloc_size, false);
+	if (ret == NULL) {
+		base_node_dealloc(node);
+		return (NULL);
+	}
+
+	offset = (uintptr_t)ret & (alignment - 1);
+	assert((offset & chunksize_mask) == 0);
+	assert(offset < alloc_size);
+	if (offset == 0) {
+		/* Trim trailing space. */
+		chunk_dealloc((void *)((uintptr_t)ret + chunk_size), alloc_size
+		    - chunk_size);
+	} else {
+		size_t trailsize;
+
+		/* Trim leading space. */
+		chunk_dealloc(ret, alignment - offset);
+
+		ret = (void *)((uintptr_t)ret + (alignment - offset));
+
+		trailsize = alloc_size - (alignment - offset) - chunk_size;
+		if (trailsize != 0) {
+		    /* Trim trailing space. */
+		    assert(trailsize < alloc_size);
+		    chunk_dealloc((void *)((uintptr_t)ret + chunk_size),
+			trailsize);
+		}
+	}
+
+	/* Insert node into huge. */
+	node->addr = ret;
+	node->size = chunk_size;
+
+	malloc_mutex_lock(&huge_mtx);
+	extent_tree_ad_insert(&huge, node);
+#ifdef MALLOC_STATS
+	huge_nmalloc++;
+	huge_allocated += chunk_size;
+#endif
+	malloc_mutex_unlock(&huge_mtx);
+
+	if (opt_junk)
+		memset(ret, 0xa5, chunk_size);
+	else if (opt_zero)
+		memset(ret, 0, chunk_size);
+
+	return (ret);
+}
+
+static void *
+huge_ralloc(void *ptr, size_t size, size_t oldsize)
+{
+	void *ret;
+	size_t copysize;
+
+	/* Avoid moving the allocation if the size class would not change. */
+	if (oldsize > arena_maxclass &&
+	    CHUNK_CEILING(size) == CHUNK_CEILING(oldsize)) {
+		if (opt_junk && size < oldsize) {
+			memset((void *)((uintptr_t)ptr + size), 0x5a, oldsize
+			    - size);
+		} else if (opt_zero && size > oldsize) {
+			memset((void *)((uintptr_t)ptr + oldsize), 0, size
+			    - oldsize);
+		}
+		return (ptr);
+	}
+
+	/*
+	 * If we get here, then size and oldsize are different enough that we
+	 * need to use a different size class.  In that case, fall back to
+	 * allocating new space and copying.
+	 */
+	ret = huge_malloc(size, false);
+	if (ret == NULL)
+		return (NULL);
+
+	copysize = (size < oldsize) ? size : oldsize;
+	memcpy(ret, ptr, copysize);
+	idalloc(ptr);
+	return (ret);
+}
+
+static void
+huge_dalloc(void *ptr)
+{
+	extent_node_t *node, key;
+
+	malloc_mutex_lock(&huge_mtx);
+
+	/* Extract from tree of huge allocations. */
+	key.addr = ptr;
+	node = extent_tree_ad_search(&huge, &key);
+	assert(node != NULL);
+	assert(node->addr == ptr);
+	extent_tree_ad_remove(&huge, node);
+
+#ifdef MALLOC_STATS
+	huge_ndalloc++;
+	huge_allocated -= node->size;
+#endif
+
+	malloc_mutex_unlock(&huge_mtx);
+
+	/* Unmap chunk. */
+#ifdef MALLOC_DSS
+	if (opt_dss && opt_junk)
+		memset(node->addr, 0x5a, node->size);
+#endif
+	chunk_dealloc(node->addr, node->size);
+
+	base_node_dealloc(node);
+}
+
+static void
+malloc_print_stats(void)
+{
+
+	if (opt_print_stats) {
+		char s[UMAX2S_BUFSIZE];
+		_malloc_message("___ Begin malloc statistics ___\n", "", "",
+		    "");
+		_malloc_message("Assertions ",
+#ifdef NDEBUG
+		    "disabled",
+#else
+		    "enabled",
+#endif
+		    "\n", "");
+		_malloc_message("Boolean MALLOC_OPTIONS: ",
+		    opt_abort ? "A" : "a", "", "");
+#ifdef MALLOC_DSS
+		_malloc_message(opt_dss ? "D" : "d", "", "", "");
+#endif
+#ifdef MALLOC_MAG
+		_malloc_message(opt_mag ? "G" : "g", "", "", "");
+#endif
+		_malloc_message(opt_junk ? "J" : "j", "", "", "");
+#ifdef MALLOC_DSS
+		_malloc_message(opt_mmap ? "M" : "m", "", "", "");
+#endif
+		_malloc_message(opt_utrace ? "PU" : "Pu",
+		    opt_sysv ? "V" : "v",
+		    opt_xmalloc ? "X" : "x",
+		    opt_zero ? "Z\n" : "z\n");
+
+		_malloc_message("CPUs: ", umax2s(ncpus, s), "\n", "");
+		_malloc_message("Max arenas: ", umax2s(narenas, s), "\n", "");
+#ifdef MALLOC_BALANCE
+		_malloc_message("Arena balance threshold: ",
+		    umax2s(opt_balance_threshold, s), "\n", "");
+#endif
+		_malloc_message("Pointer size: ", umax2s(sizeof(void *), s),
+		    "\n", "");
+		_malloc_message("Quantum size: ", umax2s(QUANTUM, s), "\n", "");
+		_malloc_message("Cacheline size (assumed): ", umax2s(CACHELINE,
+		    s), "\n", "");
+#ifdef MALLOC_TINY
+		_malloc_message("Tiny 2^n-spaced sizes: [", umax2s((1U <<
+		    TINY_MIN_2POW), s), "..", "");
+		_malloc_message(umax2s((qspace_min >> 1), s), "]\n", "", "");
+#endif
+		_malloc_message("Quantum-spaced sizes: [", umax2s(qspace_min,
+		    s), "..", "");
+		_malloc_message(umax2s(qspace_max, s), "]\n", "", "");
+		_malloc_message("Cacheline-spaced sizes: [", umax2s(cspace_min,
+		    s), "..", "");
+		_malloc_message(umax2s(cspace_max, s), "]\n", "", "");
+		_malloc_message("Subpage-spaced sizes: [", umax2s(sspace_min,
+		    s), "..", "");
+		_malloc_message(umax2s(sspace_max, s), "]\n", "", "");
+#ifdef MALLOC_MAG
+		_malloc_message("Rounds per magazine: ", umax2s(max_rounds, s),
+		    "\n", "");
+#endif
+		_malloc_message("Max dirty pages per arena: ",
+		    umax2s(opt_dirty_max, s), "\n", "");
+
+		_malloc_message("Chunk size: ", umax2s(chunksize, s), "", "");
+		_malloc_message(" (2^", umax2s(opt_chunk_2pow, s), ")\n", "");
+
+#ifdef MALLOC_STATS
+		{
+			size_t allocated, mapped;
+#ifdef MALLOC_BALANCE
+			uint64_t nbalance = 0;
+#endif
+			unsigned i;
+			arena_t *arena;
+
+			/* Calculate and print allocated/mapped stats. */
+
+			/* arenas. */
+			for (i = 0, allocated = 0; i < narenas; i++) {
+				if (arenas[i] != NULL) {
+					malloc_spin_lock(&arenas[i]->lock);
+					allocated +=
+					    arenas[i]->stats.allocated_small;
+					allocated +=
+					    arenas[i]->stats.allocated_large;
+#ifdef MALLOC_BALANCE
+					nbalance += arenas[i]->stats.nbalance;
+#endif
+					malloc_spin_unlock(&arenas[i]->lock);
+				}
+			}
+
+			/* huge/base. */
+			malloc_mutex_lock(&huge_mtx);
+			allocated += huge_allocated;
+			mapped = stats_chunks.curchunks * chunksize;
+			malloc_mutex_unlock(&huge_mtx);
+
+			malloc_mutex_lock(&base_mtx);
+			mapped += base_mapped;
+			malloc_mutex_unlock(&base_mtx);
+
+			malloc_printf("Allocated: %zu, mapped: %zu\n",
+			    allocated, mapped);
+
+#ifdef MALLOC_BALANCE
+			malloc_printf("Arena balance reassignments: %llu\n",
+			    nbalance);
+#endif
+
+			/* Print chunk stats. */
+			{
+				chunk_stats_t chunks_stats;
+
+				malloc_mutex_lock(&huge_mtx);
+				chunks_stats = stats_chunks;
+				malloc_mutex_unlock(&huge_mtx);
+
+				malloc_printf("chunks: nchunks   "
+				    "highchunks    curchunks\n");
+				malloc_printf("  %13llu%13lu%13lu\n",
+				    chunks_stats.nchunks,
+				    chunks_stats.highchunks,
+				    chunks_stats.curchunks);
+			}
+
+			/* Print chunk stats. */
+			malloc_printf(
+			    "huge: nmalloc      ndalloc    allocated\n");
+			malloc_printf(" %12llu %12llu %12zu\n",
+			    huge_nmalloc, huge_ndalloc, huge_allocated);
+
+			/* Print stats for each arena. */
+			for (i = 0; i < narenas; i++) {
+				arena = arenas[i];
+				if (arena != NULL) {
+					malloc_printf(
+					    "\narenas[%u]:\n", i);
+					malloc_spin_lock(&arena->lock);
+					stats_print(arena);
+					malloc_spin_unlock(&arena->lock);
+				}
+			}
+		}
+#endif /* #ifdef MALLOC_STATS */
+		_malloc_message("--- End malloc statistics ---\n", "", "", "");
+	}
+}
+
+#ifdef MALLOC_DEBUG
+static void
+size2bin_validate(void)
+{
+	size_t i, size, binind;
+
+	assert(size2bin[0] == 0xffU);
+	i = 1;
+#  ifdef MALLOC_TINY
+	/* Tiny. */
+	for (; i < (1U << TINY_MIN_2POW); i++) {
+		size = pow2_ceil(1U << TINY_MIN_2POW);
+		binind = ffs((int)(size >> (TINY_MIN_2POW + 1)));
+		assert(size2bin[i] == binind);
+	}
+	for (; i < qspace_min; i++) {
+		size = pow2_ceil(i);
+		binind = ffs((int)(size >> (TINY_MIN_2POW + 1)));
+		assert(size2bin[i] == binind);
+	}
+#  endif
+	/* Quantum-spaced. */
+	for (; i <= qspace_max; i++) {
+		size = QUANTUM_CEILING(i);
+		binind = ntbins + (size >> QUANTUM_2POW) - 1;
+		assert(size2bin[i] == binind);
+	}
+	/* Cacheline-spaced. */
+	for (; i <= cspace_max; i++) {
+		size = CACHELINE_CEILING(i);
+		binind = ntbins + nqbins + ((size - cspace_min) >>
+		    CACHELINE_2POW);
+		assert(size2bin[i] == binind);
+	}
+	/* Sub-page. */
+	for (; i <= sspace_max; i++) {
+		size = SUBPAGE_CEILING(i);
+		binind = ntbins + nqbins + ncbins + ((size - sspace_min)
+		    >> SUBPAGE_2POW);
+		assert(size2bin[i] == binind);
+	}
+}
+#endif
+
+static bool
+size2bin_init(void)
+{
+
+	if (opt_qspace_max_2pow != QSPACE_MAX_2POW_DEFAULT
+	    || opt_cspace_max_2pow != CSPACE_MAX_2POW_DEFAULT)
+		return (size2bin_init_hard());
+
+	size2bin = const_size2bin;
+#ifdef MALLOC_DEBUG
+	assert(sizeof(const_size2bin) == bin_maxclass + 1);
+	size2bin_validate();
+#endif
+	return (false);
+}
+
+static bool
+size2bin_init_hard(void)
+{
+	size_t i, size, binind;
+	uint8_t *custom_size2bin;
+
+	assert(opt_qspace_max_2pow != QSPACE_MAX_2POW_DEFAULT
+	    || opt_cspace_max_2pow != CSPACE_MAX_2POW_DEFAULT);
+
+	custom_size2bin = (uint8_t *)base_alloc(bin_maxclass + 1);
+	if (custom_size2bin == NULL)
+		return (true);
+
+	custom_size2bin[0] = 0xffU;
+	i = 1;
+#ifdef MALLOC_TINY
+	/* Tiny. */
+	for (; i < (1U << TINY_MIN_2POW); i++) {
+		size = pow2_ceil(1U << TINY_MIN_2POW);
+		binind = ffs((int)(size >> (TINY_MIN_2POW + 1)));
+		custom_size2bin[i] = binind;
+	}
+	for (; i < qspace_min; i++) {
+		size = pow2_ceil(i);
+		binind = ffs((int)(size >> (TINY_MIN_2POW + 1)));
+		custom_size2bin[i] = binind;
+	}
+#endif
+	/* Quantum-spaced. */
+	for (; i <= qspace_max; i++) {
+		size = QUANTUM_CEILING(i);
+		binind = ntbins + (size >> QUANTUM_2POW) - 1;
+		custom_size2bin[i] = binind;
+	}
+	/* Cacheline-spaced. */
+	for (; i <= cspace_max; i++) {
+		size = CACHELINE_CEILING(i);
+		binind = ntbins + nqbins + ((size - cspace_min) >>
+		    CACHELINE_2POW);
+		custom_size2bin[i] = binind;
+	}
+	/* Sub-page. */
+	for (; i <= sspace_max; i++) {
+		size = SUBPAGE_CEILING(i);
+		binind = ntbins + nqbins + ncbins + ((size - sspace_min) >>
+		    SUBPAGE_2POW);
+		custom_size2bin[i] = binind;
+	}
+
+	size2bin = custom_size2bin;
+#ifdef MALLOC_DEBUG
+	size2bin_validate();
+#endif
+	return (false);
+}
+
+/*
+ * FreeBSD's pthreads implementation calls malloc(3), so the malloc
+ * implementation has to take pains to avoid infinite recursion during
+ * initialization.
+ */
+static inline bool
+malloc_init(void)
+{
+
+	if (malloc_initialized == false)
+		return (malloc_init_hard());
+
+	return (false);
+}
+
+static bool
+malloc_init_hard(void)
+{
+	unsigned i;
+	int linklen;
+	char buf[PATH_MAX + 1];
+	const char *opts;
+
+	malloc_mutex_lock(&init_lock);
+	if (malloc_initialized) {
+		/*
+		 * Another thread initialized the allocator before this one
+		 * acquired init_lock.
+		 */
+		malloc_mutex_unlock(&init_lock);
+		return (false);
+	}
+
+	/* Get number of CPUs. */
+	{
+		int mib[2];
+		size_t len;
+
+		mib[0] = CTL_HW;
+		mib[1] = HW_NCPU;
+		len = sizeof(ncpus);
+		if (sysctl(mib, 2, &ncpus, &len, (void *) 0, 0) == -1) {
+			/* Error. */
+			ncpus = 1;
+		}
+	}
+
+	/* Get page size. */
+	{
+		long result;
+
+		result = sysconf(_SC_PAGESIZE);
+		assert(result != -1);
+		pagesize = (unsigned)result;
+
+		/*
+		 * We assume that pagesize is a power of 2 when calculating
+		 * pagesize_mask and pagesize_2pow.
+		 */
+		assert(((result - 1) & result) == 0);
+		pagesize_mask = result - 1;
+		pagesize_2pow = ffs((int)result) - 1;
+	}
+
+	for (i = 0; i < 3; i++) {
+		unsigned j;
+
+		/* Get runtime configuration. */
+		switch (i) {
+		case 0:
+			if ((linklen = readlink("/etc/malloc.conf", buf,
+						sizeof(buf) - 1)) != -1) {
+				/*
+				 * Use the contents of the "/etc/malloc.conf"
+				 * symbolic link's name.
+				 */
+				buf[linklen] = '\0';
+				opts = buf;
+			} else {
+				/* No configuration specified. */
+				buf[0] = '\0';
+				opts = buf;
+			}
+			break;
+		case 1:
+			if (issetugid() == 0 && (opts =
+			    getenv("MALLOC_OPTIONS")) != NULL) {
+				/*
+				 * Do nothing; opts is already initialized to
+				 * the value of the MALLOC_OPTIONS environment
+				 * variable.
+				 */
+			} else {
+				/* No configuration specified. */
+				buf[0] = '\0';
+				opts = buf;
+			}
+			break;
+		case 2:
+			if (_malloc_options != NULL) {
+				/*
+				 * Use options that were compiled into the
+				 * program.
+				 */
+				opts = _malloc_options;
+			} else {
+				/* No configuration specified. */
+				buf[0] = '\0';
+				opts = buf;
+			}
+			break;
+		default:
+			/* NOTREACHED */
+			assert(false);
+		}
+
+		for (j = 0; opts[j] != '\0'; j++) {
+			unsigned k, nreps;
+			bool nseen;
+
+			/* Parse repetition count, if any. */
+			for (nreps = 0, nseen = false;; j++, nseen = true) {
+				switch (opts[j]) {
+					case '0': case '1': case '2': case '3':
+					case '4': case '5': case '6': case '7':
+					case '8': case '9':
+						nreps *= 10;
+						nreps += opts[j] - '0';
+						break;
+					default:
+						goto MALLOC_OUT;
+				}
+			}
+MALLOC_OUT:
+			if (nseen == false)
+				nreps = 1;
+
+			for (k = 0; k < nreps; k++) {
+				switch (opts[j]) {
+				case 'a':
+					opt_abort = false;
+					break;
+				case 'A':
+					opt_abort = true;
+					break;
+				case 'b':
+#ifdef MALLOC_BALANCE
+					opt_balance_threshold >>= 1;
+#endif
+					break;
+				case 'B':
+#ifdef MALLOC_BALANCE
+					if (opt_balance_threshold == 0)
+						opt_balance_threshold = 1;
+					else if ((opt_balance_threshold << 1)
+					    > opt_balance_threshold)
+						opt_balance_threshold <<= 1;
+#endif
+					break;
+				case 'c':
+					if (opt_cspace_max_2pow - 1 >
+					    opt_qspace_max_2pow &&
+					    opt_cspace_max_2pow >
+					    CACHELINE_2POW)
+						opt_cspace_max_2pow--;
+					break;
+				case 'C':
+					if (opt_cspace_max_2pow < pagesize_2pow
+					    - 1)
+						opt_cspace_max_2pow++;
+					break;
+				case 'd':
+#ifdef MALLOC_DSS
+					opt_dss = false;
+#endif
+					break;
+				case 'D':
+#ifdef MALLOC_DSS
+					opt_dss = true;
+#endif
+					break;
+				case 'f':
+					opt_dirty_max >>= 1;
+					break;
+				case 'F':
+					if (opt_dirty_max == 0)
+						opt_dirty_max = 1;
+					else if ((opt_dirty_max << 1) != 0)
+						opt_dirty_max <<= 1;
+					break;
+#ifdef MALLOC_MAG
+				case 'g':
+					opt_mag = false;
+					break;
+				case 'G':
+					opt_mag = true;
+					break;
+#endif
+				case 'j':
+					opt_junk = false;
+					break;
+				case 'J':
+					opt_junk = true;
+					break;
+				case 'k':
+					/*
+					 * Chunks always require at least one
+					 * header page, so chunks can never be
+					 * smaller than two pages.
+					 */
+					if (opt_chunk_2pow > pagesize_2pow + 1)
+						opt_chunk_2pow--;
+					break;
+				case 'K':
+					if (opt_chunk_2pow + 1 <
+					    (sizeof(size_t) << 3))
+						opt_chunk_2pow++;
+					break;
+				case 'm':
+#ifdef MALLOC_DSS
+					opt_mmap = false;
+#endif
+					break;
+				case 'M':
+#ifdef MALLOC_DSS
+					opt_mmap = true;
+#endif
+					break;
+				case 'n':
+					opt_narenas_lshift--;
+					break;
+				case 'N':
+					opt_narenas_lshift++;
+					break;
+				case 'p':
+					opt_print_stats = false;
+					break;
+				case 'P':
+					opt_print_stats = true;
+					break;
+				case 'q':
+					if (opt_qspace_max_2pow > QUANTUM_2POW)
+						opt_qspace_max_2pow--;
+					break;
+				case 'Q':
+					if (opt_qspace_max_2pow + 1 <
+					    opt_cspace_max_2pow)
+						opt_qspace_max_2pow++;
+					break;
+#ifdef MALLOC_MAG
+				case 'R':
+					if (opt_mag_size_2pow + 1 < (8U <<
+					    SIZEOF_PTR_2POW))
+						opt_mag_size_2pow++;
+					break;
+				case 'r':
+					/*
+					 * Make sure there's always at least
+					 * one round per magazine.
+					 */
+					if ((1U << (opt_mag_size_2pow-1)) >=
+					    sizeof(mag_t))
+						opt_mag_size_2pow--;
+					break;
+#endif
+				case 'u':
+					opt_utrace = false;
+					break;
+				case 'U':
+					opt_utrace = true;
+					break;
+				case 'v':
+					opt_sysv = false;
+					break;
+				case 'V':
+					opt_sysv = true;
+					break;
+				case 'x':
+					opt_xmalloc = false;
+					break;
+				case 'X':
+					opt_xmalloc = true;
+					break;
+				case 'z':
+					opt_zero = false;
+					break;
+				case 'Z':
+					opt_zero = true;
+					break;
+				default: {
+					char cbuf[2];
+
+					cbuf[0] = opts[j];
+					cbuf[1] = '\0';
+					_malloc_message(_getprogname(),
+					    ": (malloc) Unsupported character "
+					    "in malloc options: '", cbuf,
+					    "'\n");
+				}
+				}
+			}
+		}
+	}
+
+#ifdef MALLOC_DSS
+	/* Make sure that there is some method for acquiring memory. */
+	if (opt_dss == false && opt_mmap == false)
+		opt_mmap = true;
+#endif
+
+	/* Take care to call atexit() only once. */
+	if (opt_print_stats) {
+		/* Print statistics at exit. */
+		atexit(malloc_print_stats);
+	}
+
+#ifdef MALLOC_MAG
+	/*
+	 * Calculate the actual number of rounds per magazine, taking into
+	 * account header overhead.
+	 */
+	max_rounds = (1LLU << (opt_mag_size_2pow - SIZEOF_PTR_2POW)) -
+	    (sizeof(mag_t) >> SIZEOF_PTR_2POW) + 1;
+#endif
+
+	/* Set variables according to the value of opt_[qc]space_max_2pow. */
+	qspace_max = (1U << opt_qspace_max_2pow);
+	cspace_min = CACHELINE_CEILING(qspace_max);
+	if (cspace_min == qspace_max)
+		cspace_min += CACHELINE;
+	cspace_max = (1U << opt_cspace_max_2pow);
+	sspace_min = SUBPAGE_CEILING(cspace_max);
+	if (sspace_min == cspace_max)
+		sspace_min += SUBPAGE;
+	assert(sspace_min < pagesize);
+	sspace_max = pagesize - SUBPAGE;
+
+#ifdef MALLOC_TINY
+	assert(QUANTUM_2POW >= TINY_MIN_2POW);
+#endif
+	assert(ntbins <= QUANTUM_2POW);
+	nqbins = qspace_max >> QUANTUM_2POW;
+	ncbins = ((cspace_max - cspace_min) >> CACHELINE_2POW) + 1;
+	nsbins = ((sspace_max - sspace_min) >> SUBPAGE_2POW) + 1;
+	nbins = ntbins + nqbins + ncbins + nsbins;
+
+	if (size2bin_init()) {
+		malloc_mutex_unlock(&init_lock);
+		return (true);
+	}
+
+	/* Set variables according to the value of opt_chunk_2pow. */
+	chunksize = (1LU << opt_chunk_2pow);
+	chunksize_mask = chunksize - 1;
+	chunk_npages = (chunksize >> pagesize_2pow);
+	{
+		size_t header_size;
+
+		/*
+		 * Compute the header size such that it is large enough to
+		 * contain the page map.
+		 */
+		header_size = sizeof(arena_chunk_t) +
+		    (sizeof(arena_chunk_map_t) * (chunk_npages - 1));
+		arena_chunk_header_npages = (header_size >> pagesize_2pow) +
+		    ((header_size & pagesize_mask) != 0);
+	}
+	arena_maxclass = chunksize - (arena_chunk_header_npages <<
+	    pagesize_2pow);
+
+	UTRACE(0, 0, 0);
+
+#ifdef MALLOC_STATS
+	memset(&stats_chunks, 0, sizeof(chunk_stats_t));
+#endif
+
+	/* Various sanity checks that regard configuration. */
+	assert(chunksize >= pagesize);
+
+	/* Initialize chunks data. */
+	malloc_mutex_init(&huge_mtx);
+	extent_tree_ad_new(&huge);
+#ifdef MALLOC_DSS
+	malloc_mutex_init(&dss_mtx);
+	dss_base = sbrk(0);
+	dss_prev = dss_base;
+	dss_max = dss_base;
+	extent_tree_szad_new(&dss_chunks_szad);
+	extent_tree_ad_new(&dss_chunks_ad);
+#endif
+#ifdef MALLOC_STATS
+	huge_nmalloc = 0;
+	huge_ndalloc = 0;
+	huge_allocated = 0;
+#endif
+
+	/* Initialize base allocation data structures. */
+#ifdef MALLOC_STATS
+	base_mapped = 0;
+#endif
+#ifdef MALLOC_DSS
+	/*
+	 * Allocate a base chunk here, since it doesn't actually have to be
+	 * chunk-aligned.  Doing this before allocating any other chunks allows
+	 * the use of space that would otherwise be wasted.
+	 */
+	if (opt_dss)
+		base_pages_alloc(0);
+#endif
+	base_nodes = NULL;
+	malloc_mutex_init(&base_mtx);
+
+	if (ncpus > 1) {
+		/*
+		 * For SMP systems, create twice as many arenas as there are
+		 * CPUs by default.
+		 */
+		opt_narenas_lshift++;
+	}
+
+	/* Determine how many arenas to use. */
+	narenas = ncpus;
+	if (opt_narenas_lshift > 0) {
+		if ((narenas << opt_narenas_lshift) > narenas)
+			narenas <<= opt_narenas_lshift;
+		/*
+		 * Make sure not to exceed the limits of what base_alloc() can
+		 * handle.
+		 */
+		if (narenas * sizeof(arena_t *) > chunksize)
+			narenas = chunksize / sizeof(arena_t *);
+	} else if (opt_narenas_lshift < 0) {
+		if ((narenas >> -opt_narenas_lshift) < narenas)
+			narenas >>= -opt_narenas_lshift;
+		/* Make sure there is at least one arena. */
+		if (narenas == 0)
+			narenas = 1;
+	}
+#ifdef MALLOC_BALANCE
+	assert(narenas != 0);
+	for (narenas_2pow = 0;
+	     (narenas >> (narenas_2pow + 1)) != 0;
+	     narenas_2pow++);
+#endif
+
+#ifdef NO_TLS
+	if (narenas > 1) {
+		static const unsigned primes[] = {1, 3, 5, 7, 11, 13, 17, 19,
+		    23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83,
+		    89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149,
+		    151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211,
+		    223, 227, 229, 233, 239, 241, 251, 257, 263};
+		unsigned nprimes, parenas;
+
+		/*
+		 * Pick a prime number of hash arenas that is more than narenas
+		 * so that direct hashing of pthread_self() pointers tends to
+		 * spread allocations evenly among the arenas.
+		 */
+		assert((narenas & 1) == 0); /* narenas must be even. */
+		nprimes = (sizeof(primes) >> SIZEOF_INT_2POW);
+		parenas = primes[nprimes - 1]; /* In case not enough primes. */
+		for (i = 1; i < nprimes; i++) {
+			if (primes[i] > narenas) {
+				parenas = primes[i];
+				break;
+			}
+		}
+		narenas = parenas;
+	}
+#endif
+
+#ifndef NO_TLS
+#  ifndef MALLOC_BALANCE
+	next_arena = 0;
+#  endif
+#endif
+
+	/* Allocate and initialize arenas. */
+	arenas = (arena_t **)base_alloc(sizeof(arena_t *) * narenas);
+	if (arenas == NULL) {
+		malloc_mutex_unlock(&init_lock);
+		return (true);
+	}
+	/*
+	 * Zero the array.  In practice, this should always be pre-zeroed,
+	 * since it was just mmap()ed, but let's be sure.
+	 */
+	memset(arenas, 0, sizeof(arena_t *) * narenas);
+
+	/*
+	 * Initialize one arena here.  The rest are lazily created in
+	 * choose_arena_hard().
+	 */
+	arenas_extend(0);
+	if (arenas[0] == NULL) {
+		malloc_mutex_unlock(&init_lock);
+		return (true);
+	}
+#ifndef NO_TLS
+	/*
+	 * Assign the initial arena to the initial thread, in order to avoid
+	 * spurious creation of an extra arena if the application switches to
+	 * threaded mode.
+	 */
+	arenas_map = arenas[0];
+#endif
+	/*
+	 * Seed here for the initial thread, since choose_arena_hard() is only
+	 * called for other threads.  The seed value doesn't really matter.
+	 */
+#ifdef MALLOC_BALANCE
+	SPRN(balance, 42);
+#endif
+
+	malloc_spin_init(&arenas_lock);
+
+	malloc_initialized = true;
+	malloc_mutex_unlock(&init_lock);
+	return (false);
+}
+
+/*
+ * End general internal functions.
+ */
+/******************************************************************************/
+/*
+ * Begin malloc(3)-compatible functions.
+ */
+
+void *
+malloc(size_t size)
+{
+	void *ret;
+
+	if (malloc_init()) {
+		ret = NULL;
+		goto RETURN;
+	}
+
+	if (size == 0) {
+		if (opt_sysv == false)
+			size = 1;
+		else {
+			ret = NULL;
+			goto RETURN;
+		}
+	}
+
+	ret = imalloc(size);
+
+RETURN:
+	if (ret == NULL) {
+		if (opt_xmalloc) {
+			_malloc_message(_getprogname(),
+			    ": (malloc) Error in malloc(): out of memory\n", "",
+			    "");
+			abort();
+		}
+		errno = ENOMEM;
+	}
+
+	UTRACE(0, size, ret);
+	return (ret);
+}
+
+int
+posix_memalign(void **memptr, size_t alignment, size_t size)
+{
+	int ret;
+	void *result;
+
+	if (malloc_init())
+		result = NULL;
+	else {
+		/* Make sure that alignment is a large enough power of 2. */
+		if (((alignment - 1) & alignment) != 0
+		    || alignment < sizeof(void *)) {
+			if (opt_xmalloc) {
+				_malloc_message(_getprogname(),
+				    ": (malloc) Error in posix_memalign(): "
+				    "invalid alignment\n", "", "");
+				abort();
+			}
+			result = NULL;
+			ret = EINVAL;
+			goto RETURN;
+		}
+
+		result = ipalloc(alignment, size);
+	}
+
+	if (result == NULL) {
+		if (opt_xmalloc) {
+			_malloc_message(_getprogname(),
+			": (malloc) Error in posix_memalign(): out of memory\n",
+			"", "");
+			abort();
+		}
+		ret = ENOMEM;
+		goto RETURN;
+	}
+
+	*memptr = result;
+	ret = 0;
+
+RETURN:
+	UTRACE(0, size, result);
+	return (ret);
+}
+
+void *
+calloc(size_t num, size_t size)
+{
+	void *ret;
+	size_t num_size;
+
+	if (malloc_init()) {
+		num_size = 0;
+		ret = NULL;
+		goto RETURN;
+	}
+
+	num_size = num * size;
+	if (num_size == 0) {
+		if ((opt_sysv == false) && ((num == 0) || (size == 0)))
+			num_size = 1;
+		else {
+			ret = NULL;
+			goto RETURN;
+		}
+	/*
+	 * Try to avoid division here.  We know that it isn't possible to
+	 * overflow during multiplication if neither operand uses any of the
+	 * most significant half of the bits in a size_t.
+	 */
+	} else if (((num | size) & (SIZE_T_MAX << (sizeof(size_t) << 2)))
+	    && (num_size / size != num)) {
+		/* size_t overflow. */
+		ret = NULL;
+		goto RETURN;
+	}
+
+	ret = icalloc(num_size);
+
+RETURN:
+	if (ret == NULL) {
+		if (opt_xmalloc) {
+			_malloc_message(_getprogname(),
+			    ": (malloc) Error in calloc(): out of memory\n", "",
+			    "");
+			abort();
+		}
+		errno = ENOMEM;
+	}
+
+	UTRACE(0, num_size, ret);
+	return (ret);
+}
+
+void *
+realloc(void *ptr, size_t size)
+{
+	void *ret;
+
+	if (size == 0) {
+		if (opt_sysv == false)
+			size = 1;
+		else {
+			if (ptr != NULL)
+				idalloc(ptr);
+			ret = NULL;
+			goto RETURN;
+		}
+	}
+
+	if (ptr != NULL) {
+		assert(malloc_initialized);
+
+		ret = iralloc(ptr, size);
+
+		if (ret == NULL) {
+			if (opt_xmalloc) {
+				_malloc_message(_getprogname(),
+				    ": (malloc) Error in realloc(): out of "
+				    "memory\n", "", "");
+				abort();
+			}
+			errno = ENOMEM;
+		}
+	} else {
+		if (malloc_init())
+			ret = NULL;
+		else
+			ret = imalloc(size);
+
+		if (ret == NULL) {
+			if (opt_xmalloc) {
+				_malloc_message(_getprogname(),
+				    ": (malloc) Error in realloc(): out of "
+				    "memory\n", "", "");
+				abort();
+			}
+			errno = ENOMEM;
+		}
+	}
+
+RETURN:
+	UTRACE(ptr, size, ret);
+	return (ret);
+}
+
+void
+free(void *ptr)
+{
+
+	UTRACE(ptr, 0, 0);
+	if (ptr != NULL) {
+		assert(malloc_initialized);
+
+		idalloc(ptr);
+	}
+}
+
+/*
+ * End malloc(3)-compatible functions.
+ */
+/******************************************************************************/
+/*
+ * Begin non-standard functions.
+ */
+
+size_t
+malloc_usable_size(const void *ptr)
+{
+
+	assert(ptr != NULL);
+
+	return (isalloc(ptr));
+}
+
+/*
+ * End non-standard functions.
+ */
+/******************************************************************************/
+/*
+ * Begin library-private functions.
+ */
+
+/******************************************************************************/
+/*
+ * Begin thread cache.
+ */
+
+/*
+ * We provide an unpublished interface in order to receive notifications from
+ * the pthreads library whenever a thread exits.  This allows us to clean up
+ * thread caches.
+ */
+void
+_malloc_thread_cleanup(void)
+{
+
+#ifdef MALLOC_MAG
+	if (mag_rack != NULL) {
+		assert(mag_rack != (void *)-1);
+		mag_rack_destroy(mag_rack);
+#ifdef MALLOC_DEBUG
+		mag_rack = (void *)-1;
+#endif
+	}
+#endif
+}
+
+/*
+ * The following functions are used by threading libraries for protection of
+ * malloc during fork().  These functions are only called if the program is
+ * running in threaded mode, so there is no need to check whether the program
+ * is threaded here.
+ */
+
+void
+_malloc_prefork(void)
+{
+	unsigned i;
+
+	/* Acquire all mutexes in a safe order. */
+
+	malloc_spin_lock(&arenas_lock);
+	for (i = 0; i < narenas; i++) {
+		if (arenas[i] != NULL)
+			malloc_spin_lock(&arenas[i]->lock);
+	}
+	malloc_spin_unlock(&arenas_lock);
+
+	malloc_mutex_lock(&base_mtx);
+
+	malloc_mutex_lock(&huge_mtx);
+
+#ifdef MALLOC_DSS
+	malloc_mutex_lock(&dss_mtx);
+#endif
+}
+
+void
+_malloc_postfork(void)
+{
+	unsigned i;
+
+	/* Release all mutexes, now that fork() has completed. */
+
+#ifdef MALLOC_DSS
+	malloc_mutex_unlock(&dss_mtx);
+#endif
+
+	malloc_mutex_unlock(&huge_mtx);
+
+	malloc_mutex_unlock(&base_mtx);
+
+	malloc_spin_lock(&arenas_lock);
+	for (i = 0; i < narenas; i++) {
+		if (arenas[i] != NULL)
+			malloc_spin_unlock(&arenas[i]->lock);
+	}
+	malloc_spin_unlock(&arenas_lock);
+}
+
+/*
+ * End library-private functions.
+ */
+/******************************************************************************/

Added: trunk/varnish-cache/lib/libjemalloc/rb.h
===================================================================
--- trunk/varnish-cache/lib/libjemalloc/rb.h	                        (rev 0)
+++ trunk/varnish-cache/lib/libjemalloc/rb.h	2008-09-24 12:41:27 UTC (rev 3215)
@@ -0,0 +1,946 @@
+/******************************************************************************
+ *
+ * Copyright (C) 2008 Jason Evans <jasone at FreeBSD.org>.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice(s), this list of conditions and the following disclaimer
+ *    unmodified other than the allowable addition of one or more
+ *    copyright notices.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice(s), this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ ******************************************************************************
+ *
+ * cpp macro implementation of left-leaning red-black trees.
+ *
+ * Usage:
+ *
+ *   (Optional, see assert(3).)
+ *   #define NDEBUG
+ *
+ *   (Required.)
+ *   #include <assert.h>
+ *   #include <rb.h>
+ *   ...
+ *
+ * All operations are done non-recursively.  Parent pointers are not used, and
+ * color bits are stored in the least significant bit of right-child pointers,
+ * thus making node linkage as compact as is possible for red-black trees.
+ *
+ * Some macros use a comparison function pointer, which is expected to have the
+ * following prototype:
+ *
+ *   int (a_cmp *)(a_type *a_node, a_type *a_other);
+ *                         ^^^^^^
+ *                      or a_key
+ *
+ * Interpretation of comparision function return values:
+ *
+ *   -1 : a_node <  a_other
+ *    0 : a_node == a_other
+ *    1 : a_node >  a_other
+ *
+ * In all cases, the a_node or a_key macro argument is the first argument to the
+ * comparison function, which makes it possible to write comparison functions
+ * that treat the first argument specially.
+ *
+ ******************************************************************************/
+
+#ifndef RB_H_
+#define	RB_H_
+
+//__FBSDID("$FreeBSD: head/lib/libc/stdlib/rb.h 178995 2008-05-14 18:33:13Z jasone $");
+
+/* Node structure. */
+#define	rb_node(a_type)							\
+struct {								\
+    a_type *rbn_left;							\
+    a_type *rbn_right_red;						\
+}
+
+/* Root structure. */
+#define	rb_tree(a_type)							\
+struct {								\
+    a_type *rbt_root;							\
+    a_type rbt_nil;							\
+}
+
+/* Left accessors. */
+#define	rbp_left_get(a_type, a_field, a_node)				\
+    ((a_node)->a_field.rbn_left)
+#define	rbp_left_set(a_type, a_field, a_node, a_left) do {		\
+    (a_node)->a_field.rbn_left = a_left;				\
+} while (0)
+
+/* Right accessors. */
+#define	rbp_right_get(a_type, a_field, a_node)				\
+    ((a_type *) (((intptr_t) (a_node)->a_field.rbn_right_red)		\
+      & ((ssize_t)-2)))
+#define	rbp_right_set(a_type, a_field, a_node, a_right) do {		\
+    (a_node)->a_field.rbn_right_red = (a_type *) (((uintptr_t) a_right)	\
+      | (((uintptr_t) (a_node)->a_field.rbn_right_red) & ((size_t)1)));	\
+} while (0)
+
+/* Color accessors. */
+#define	rbp_red_get(a_type, a_field, a_node)				\
+    ((bool) (((uintptr_t) (a_node)->a_field.rbn_right_red)		\
+      & ((size_t)1)))
+#define	rbp_color_set(a_type, a_field, a_node, a_red) do {		\
+    (a_node)->a_field.rbn_right_red = (a_type *) ((((intptr_t)		\
+      (a_node)->a_field.rbn_right_red) & ((ssize_t)-2))			\
+      | ((ssize_t)a_red));						\
+} while (0)
+#define	rbp_red_set(a_type, a_field, a_node) do {			\
+    (a_node)->a_field.rbn_right_red = (a_type *) (((uintptr_t)		\
+      (a_node)->a_field.rbn_right_red) | ((size_t)1));			\
+} while (0)
+#define	rbp_black_set(a_type, a_field, a_node) do {			\
+    (a_node)->a_field.rbn_right_red = (a_type *) (((intptr_t)		\
+      (a_node)->a_field.rbn_right_red) & ((ssize_t)-2));		\
+} while (0)
+
+/* Node initializer. */
+#define	rbp_node_new(a_type, a_field, a_tree, a_node) do {		\
+    rbp_left_set(a_type, a_field, (a_node), &(a_tree)->rbt_nil);	\
+    rbp_right_set(a_type, a_field, (a_node), &(a_tree)->rbt_nil);	\
+    rbp_red_set(a_type, a_field, (a_node));				\
+} while (0)
+
+/* Tree initializer. */
+#define	rb_new(a_type, a_field, a_tree) do {				\
+    (a_tree)->rbt_root = &(a_tree)->rbt_nil;				\
+    rbp_node_new(a_type, a_field, a_tree, &(a_tree)->rbt_nil);		\
+    rbp_black_set(a_type, a_field, &(a_tree)->rbt_nil);			\
+} while (0)
+
+/* Tree operations. */
+#define	rbp_black_height(a_type, a_field, a_tree, r_height) do {	\
+    a_type *rbp_bh_t;							\
+    for (rbp_bh_t = (a_tree)->rbt_root, (r_height) = 0;			\
+      rbp_bh_t != &(a_tree)->rbt_nil;					\
+      rbp_bh_t = rbp_left_get(a_type, a_field, rbp_bh_t)) {		\
+	if (rbp_red_get(a_type, a_field, rbp_bh_t) == false) {		\
+	    (r_height)++;						\
+	}								\
+    }									\
+} while (0)
+
+#define	rbp_first(a_type, a_field, a_tree, a_root, r_node) do {		\
+    for ((r_node) = (a_root);						\
+      rbp_left_get(a_type, a_field, (r_node)) != &(a_tree)->rbt_nil;	\
+      (r_node) = rbp_left_get(a_type, a_field, (r_node))) {		\
+    }									\
+} while (0)
+
+#define	rbp_last(a_type, a_field, a_tree, a_root, r_node) do {		\
+    for ((r_node) = (a_root);						\
+      rbp_right_get(a_type, a_field, (r_node)) != &(a_tree)->rbt_nil;	\
+      (r_node) = rbp_right_get(a_type, a_field, (r_node))) {		\
+    }									\
+} while (0)
+
+#define	rbp_next(a_type, a_field, a_cmp, a_tree, a_node, r_node) do {	\
+    if (rbp_right_get(a_type, a_field, (a_node))			\
+      != &(a_tree)->rbt_nil) {						\
+	rbp_first(a_type, a_field, a_tree, rbp_right_get(a_type,	\
+	  a_field, (a_node)), (r_node));				\
+    } else {								\
+	a_type *rbp_n_t = (a_tree)->rbt_root;				\
+	assert(rbp_n_t != &(a_tree)->rbt_nil);				\
+	(r_node) = &(a_tree)->rbt_nil;					\
+	while (true) {							\
+	    int rbp_n_cmp = (a_cmp)((a_node), rbp_n_t);			\
+	    if (rbp_n_cmp < 0) {					\
+		(r_node) = rbp_n_t;					\
+		rbp_n_t = rbp_left_get(a_type, a_field, rbp_n_t);	\
+	    } else if (rbp_n_cmp > 0) {					\
+		rbp_n_t = rbp_right_get(a_type, a_field, rbp_n_t);	\
+	    } else {							\
+		break;							\
+	    }								\
+	    assert(rbp_n_t != &(a_tree)->rbt_nil);			\
+	}								\
+    }									\
+} while (0)
+
+#define	rbp_prev(a_type, a_field, a_cmp, a_tree, a_node, r_node) do {	\
+    if (rbp_left_get(a_type, a_field, (a_node)) != &(a_tree)->rbt_nil) {\
+	rbp_last(a_type, a_field, a_tree, rbp_left_get(a_type,		\
+	  a_field, (a_node)), (r_node));				\
+    } else {								\
+	a_type *rbp_p_t = (a_tree)->rbt_root;				\
+	assert(rbp_p_t != &(a_tree)->rbt_nil);				\
+	(r_node) = &(a_tree)->rbt_nil;					\
+	while (true) {							\
+	    int rbp_p_cmp = (a_cmp)((a_node), rbp_p_t);			\
+	    if (rbp_p_cmp < 0) {					\
+		rbp_p_t = rbp_left_get(a_type, a_field, rbp_p_t);	\
+	    } else if (rbp_p_cmp > 0) {					\
+		(r_node) = rbp_p_t;					\
+		rbp_p_t = rbp_right_get(a_type, a_field, rbp_p_t);	\
+	    } else {							\
+		break;							\
+	    }								\
+	    assert(rbp_p_t != &(a_tree)->rbt_nil);			\
+	}								\
+    }									\
+} while (0)
+
+#define	rb_first(a_type, a_field, a_tree, r_node) do {			\
+    rbp_first(a_type, a_field, a_tree, (a_tree)->rbt_root, (r_node));	\
+    if ((r_node) == &(a_tree)->rbt_nil) {				\
+	(r_node) = NULL;						\
+    }									\
+} while (0)
+
+#define	rb_last(a_type, a_field, a_tree, r_node) do {			\
+    rbp_last(a_type, a_field, a_tree, (a_tree)->rbt_root, r_node);	\
+    if ((r_node) == &(a_tree)->rbt_nil) {				\
+	(r_node) = NULL;						\
+    }									\
+} while (0)
+
+#define	rb_next(a_type, a_field, a_cmp, a_tree, a_node, r_node) do {	\
+    rbp_next(a_type, a_field, a_cmp, a_tree, (a_node), (r_node));	\
+    if ((r_node) == &(a_tree)->rbt_nil) {				\
+	(r_node) = NULL;						\
+    }									\
+} while (0)
+
+#define	rb_prev(a_type, a_field, a_cmp, a_tree, a_node, r_node) do {	\
+    rbp_prev(a_type, a_field, a_cmp, a_tree, (a_node), (r_node));	\
+    if ((r_node) == &(a_tree)->rbt_nil) {				\
+	(r_node) = NULL;						\
+    }									\
+} while (0)
+
+#define	rb_search(a_type, a_field, a_cmp, a_tree, a_key, r_node) do {	\
+    int rbp_se_cmp;							\
+    (r_node) = (a_tree)->rbt_root;					\
+    while ((r_node) != &(a_tree)->rbt_nil				\
+      && (rbp_se_cmp = (a_cmp)((a_key), (r_node))) != 0) {		\
+	if (rbp_se_cmp < 0) {						\
+	    (r_node) = rbp_left_get(a_type, a_field, (r_node));		\
+	} else {							\
+	    (r_node) = rbp_right_get(a_type, a_field, (r_node));	\
+	}								\
+    }									\
+    if ((r_node) == &(a_tree)->rbt_nil) {				\
+	(r_node) = NULL;						\
+    }									\
+} while (0)
+
+/*
+ * Find a match if it exists.  Otherwise, find the next greater node, if one
+ * exists.
+ */
+#define	rb_nsearch(a_type, a_field, a_cmp, a_tree, a_key, r_node) do {	\
+    a_type *rbp_ns_t = (a_tree)->rbt_root;				\
+    (r_node) = NULL;							\
+    while (rbp_ns_t != &(a_tree)->rbt_nil) {				\
+	int rbp_ns_cmp = (a_cmp)((a_key), rbp_ns_t);			\
+	if (rbp_ns_cmp < 0) {						\
+	    (r_node) = rbp_ns_t;					\
+	    rbp_ns_t = rbp_left_get(a_type, a_field, rbp_ns_t);		\
+	} else if (rbp_ns_cmp > 0) {					\
+	    rbp_ns_t = rbp_right_get(a_type, a_field, rbp_ns_t);	\
+	} else {							\
+	    (r_node) = rbp_ns_t;					\
+	    break;							\
+	}								\
+    }									\
+} while (0)
+
+/*
+ * Find a match if it exists.  Otherwise, find the previous lesser node, if one
+ * exists.
+ */
+#define	rb_psearch(a_type, a_field, a_cmp, a_tree, a_key, r_node) do {	\
+    a_type *rbp_ps_t = (a_tree)->rbt_root;				\
+    (r_node) = NULL;							\
+    while (rbp_ps_t != &(a_tree)->rbt_nil) {				\
+	int rbp_ps_cmp = (a_cmp)((a_key), rbp_ps_t);			\
+	if (rbp_ps_cmp < 0) {						\
+	    rbp_ps_t = rbp_left_get(a_type, a_field, rbp_ps_t);		\
+	} else if (rbp_ps_cmp > 0) {					\
+	    (r_node) = rbp_ps_t;					\
+	    rbp_ps_t = rbp_right_get(a_type, a_field, rbp_ps_t);	\
+	} else {							\
+	    (r_node) = rbp_ps_t;					\
+	    break;							\
+	}								\
+    }									\
+} while (0)
+
+#define	rbp_rotate_left(a_type, a_field, a_node, r_node) do {		\
+    (r_node) = rbp_right_get(a_type, a_field, (a_node));		\
+    rbp_right_set(a_type, a_field, (a_node),				\
+      rbp_left_get(a_type, a_field, (r_node)));				\
+    rbp_left_set(a_type, a_field, (r_node), (a_node));			\
+} while (0)
+
+#define	rbp_rotate_right(a_type, a_field, a_node, r_node) do {		\
+    (r_node) = rbp_left_get(a_type, a_field, (a_node));			\
+    rbp_left_set(a_type, a_field, (a_node),				\
+      rbp_right_get(a_type, a_field, (r_node)));			\
+    rbp_right_set(a_type, a_field, (r_node), (a_node));			\
+} while (0)
+
+#define	rbp_lean_left(a_type, a_field, a_node, r_node) do {		\
+    bool rbp_ll_red;							\
+    rbp_rotate_left(a_type, a_field, (a_node), (r_node));		\
+    rbp_ll_red = rbp_red_get(a_type, a_field, (a_node));		\
+    rbp_color_set(a_type, a_field, (r_node), rbp_ll_red);		\
+    rbp_red_set(a_type, a_field, (a_node));				\
+} while (0)
+
+#define	rbp_lean_right(a_type, a_field, a_node, r_node) do {		\
+    bool rbp_lr_red;							\
+    rbp_rotate_right(a_type, a_field, (a_node), (r_node));		\
+    rbp_lr_red = rbp_red_get(a_type, a_field, (a_node));		\
+    rbp_color_set(a_type, a_field, (r_node), rbp_lr_red);		\
+    rbp_red_set(a_type, a_field, (a_node));				\
+} while (0)
+
+#define	rbp_move_red_left(a_type, a_field, a_node, r_node) do {		\
+    a_type *rbp_mrl_t, *rbp_mrl_u;					\
+    rbp_mrl_t = rbp_left_get(a_type, a_field, (a_node));		\
+    rbp_red_set(a_type, a_field, rbp_mrl_t);				\
+    rbp_mrl_t = rbp_right_get(a_type, a_field, (a_node));		\
+    rbp_mrl_u = rbp_left_get(a_type, a_field, rbp_mrl_t);		\
+    if (rbp_red_get(a_type, a_field, rbp_mrl_u)) {			\
+	rbp_rotate_right(a_type, a_field, rbp_mrl_t, rbp_mrl_u);	\
+	rbp_right_set(a_type, a_field, (a_node), rbp_mrl_u);		\
+	rbp_rotate_left(a_type, a_field, (a_node), (r_node));		\
+	rbp_mrl_t = rbp_right_get(a_type, a_field, (a_node));		\
+	if (rbp_red_get(a_type, a_field, rbp_mrl_t)) {			\
+	    rbp_black_set(a_type, a_field, rbp_mrl_t);			\
+	    rbp_red_set(a_type, a_field, (a_node));			\
+	    rbp_rotate_left(a_type, a_field, (a_node), rbp_mrl_t);	\
+	    rbp_left_set(a_type, a_field, (r_node), rbp_mrl_t);		\
+	} else {							\
+	    rbp_black_set(a_type, a_field, (a_node));			\
+	}								\
+    } else {								\
+	rbp_red_set(a_type, a_field, (a_node));				\
+	rbp_rotate_left(a_type, a_field, (a_node), (r_node));		\
+    }									\
+} while (0)
+
+#define	rbp_move_red_right(a_type, a_field, a_node, r_node) do {	\
+    a_type *rbp_mrr_t;							\
+    rbp_mrr_t = rbp_left_get(a_type, a_field, (a_node));		\
+    if (rbp_red_get(a_type, a_field, rbp_mrr_t)) {			\
+	a_type *rbp_mrr_u, *rbp_mrr_v;					\
+	rbp_mrr_u = rbp_right_get(a_type, a_field, rbp_mrr_t);		\
+	rbp_mrr_v = rbp_left_get(a_type, a_field, rbp_mrr_u);		\
+	if (rbp_red_get(a_type, a_field, rbp_mrr_v)) {			\
+	    rbp_color_set(a_type, a_field, rbp_mrr_u,			\
+	      rbp_red_get(a_type, a_field, (a_node)));			\
+	    rbp_black_set(a_type, a_field, rbp_mrr_v);			\
+	    rbp_rotate_left(a_type, a_field, rbp_mrr_t, rbp_mrr_u);	\
+	    rbp_left_set(a_type, a_field, (a_node), rbp_mrr_u);		\
+	    rbp_rotate_right(a_type, a_field, (a_node), (r_node));	\
+	    rbp_rotate_left(a_type, a_field, (a_node), rbp_mrr_t);	\
+	    rbp_right_set(a_type, a_field, (r_node), rbp_mrr_t);	\
+	} else {							\
+	    rbp_color_set(a_type, a_field, rbp_mrr_t,			\
+	      rbp_red_get(a_type, a_field, (a_node)));			\
+	    rbp_red_set(a_type, a_field, rbp_mrr_u);			\
+	    rbp_rotate_right(a_type, a_field, (a_node), (r_node));	\
+	    rbp_rotate_left(a_type, a_field, (a_node), rbp_mrr_t);	\
+	    rbp_right_set(a_type, a_field, (r_node), rbp_mrr_t);	\
+	}								\
+	rbp_red_set(a_type, a_field, (a_node));				\
+    } else {								\
+	rbp_red_set(a_type, a_field, rbp_mrr_t);			\
+	rbp_mrr_t = rbp_left_get(a_type, a_field, rbp_mrr_t);		\
+	if (rbp_red_get(a_type, a_field, rbp_mrr_t)) {			\
+	    rbp_black_set(a_type, a_field, rbp_mrr_t);			\
+	    rbp_rotate_right(a_type, a_field, (a_node), (r_node));	\
+	    rbp_rotate_left(a_type, a_field, (a_node), rbp_mrr_t);	\
+	    rbp_right_set(a_type, a_field, (r_node), rbp_mrr_t);	\
+	} else {							\
+	    rbp_rotate_left(a_type, a_field, (a_node), (r_node));	\
+	}								\
+    }									\
+} while (0)
+
+#define	rb_insert(a_type, a_field, a_cmp, a_tree, a_node) do {		\
+    a_type rbp_i_s;							\
+    a_type *rbp_i_g, *rbp_i_p, *rbp_i_c, *rbp_i_t, *rbp_i_u;		\
+    int rbp_i_cmp = 0;							\
+    rbp_i_g = &(a_tree)->rbt_nil;					\
+    rbp_left_set(a_type, a_field, &rbp_i_s, (a_tree)->rbt_root);	\
+    rbp_right_set(a_type, a_field, &rbp_i_s, &(a_tree)->rbt_nil);	\
+    rbp_black_set(a_type, a_field, &rbp_i_s);				\
+    rbp_i_p = &rbp_i_s;							\
+    rbp_i_c = (a_tree)->rbt_root;					\
+    /* Iteratively search down the tree for the insertion point,      */\
+    /* splitting 4-nodes as they are encountered.  At the end of each */\
+    /* iteration, rbp_i_g->rbp_i_p->rbp_i_c is a 3-level path down    */\
+    /* the tree, assuming a sufficiently deep tree.                   */\
+    while (rbp_i_c != &(a_tree)->rbt_nil) {				\
+	rbp_i_t = rbp_left_get(a_type, a_field, rbp_i_c);		\
+	rbp_i_u = rbp_left_get(a_type, a_field, rbp_i_t);		\
+	if (rbp_red_get(a_type, a_field, rbp_i_t)			\
+	  && rbp_red_get(a_type, a_field, rbp_i_u)) {			\
+	    /* rbp_i_c is the top of a logical 4-node, so split it.   */\
+	    /* This iteration does not move down the tree, due to the */\
+	    /* disruptiveness of node splitting.                      */\
+	    /*                                                        */\
+	    /* Rotate right.                                          */\
+	    rbp_rotate_right(a_type, a_field, rbp_i_c, rbp_i_t);	\
+	    /* Pass red links up one level.                           */\
+	    rbp_i_u = rbp_left_get(a_type, a_field, rbp_i_t);		\
+	    rbp_black_set(a_type, a_field, rbp_i_u);			\
+	    if (rbp_left_get(a_type, a_field, rbp_i_p) == rbp_i_c) {	\
+		rbp_left_set(a_type, a_field, rbp_i_p, rbp_i_t);	\
+		rbp_i_c = rbp_i_t;					\
+	    } else {							\
+		/* rbp_i_c was the right child of rbp_i_p, so rotate  */\
+		/* left in order to maintain the left-leaning         */\
+		/* invariant.                                         */\
+		assert(rbp_right_get(a_type, a_field, rbp_i_p)		\
+		  == rbp_i_c);						\
+		rbp_right_set(a_type, a_field, rbp_i_p, rbp_i_t);	\
+		rbp_lean_left(a_type, a_field, rbp_i_p, rbp_i_u);	\
+		if (rbp_left_get(a_type, a_field, rbp_i_g) == rbp_i_p) {\
+		    rbp_left_set(a_type, a_field, rbp_i_g, rbp_i_u);	\
+		} else {						\
+		    assert(rbp_right_get(a_type, a_field, rbp_i_g)	\
+		      == rbp_i_p);					\
+		    rbp_right_set(a_type, a_field, rbp_i_g, rbp_i_u);	\
+		}							\
+		rbp_i_p = rbp_i_u;					\
+		rbp_i_cmp = (a_cmp)((a_node), rbp_i_p);			\
+		if (rbp_i_cmp < 0) {					\
+		    rbp_i_c = rbp_left_get(a_type, a_field, rbp_i_p);	\
+		} else {						\
+		    assert(rbp_i_cmp > 0);				\
+		    rbp_i_c = rbp_right_get(a_type, a_field, rbp_i_p);	\
+		}							\
+		continue;						\
+	    }								\
+	}								\
+	rbp_i_g = rbp_i_p;						\
+	rbp_i_p = rbp_i_c;						\
+	rbp_i_cmp = (a_cmp)((a_node), rbp_i_c);				\
+	if (rbp_i_cmp < 0) {						\
+	    rbp_i_c = rbp_left_get(a_type, a_field, rbp_i_c);		\
+	} else {							\
+	    assert(rbp_i_cmp > 0);					\
+	    rbp_i_c = rbp_right_get(a_type, a_field, rbp_i_c);		\
+	}								\
+    }									\
+    /* rbp_i_p now refers to the node under which to insert.          */\
+    rbp_node_new(a_type, a_field, a_tree, (a_node));			\
+    if (rbp_i_cmp > 0) {						\
+	rbp_right_set(a_type, a_field, rbp_i_p, (a_node));		\
+	rbp_lean_left(a_type, a_field, rbp_i_p, rbp_i_t);		\
+	if (rbp_left_get(a_type, a_field, rbp_i_g) == rbp_i_p) {	\
+	    rbp_left_set(a_type, a_field, rbp_i_g, rbp_i_t);		\
+	} else if (rbp_right_get(a_type, a_field, rbp_i_g) == rbp_i_p) {\
+	    rbp_right_set(a_type, a_field, rbp_i_g, rbp_i_t);		\
+	}								\
+    } else {								\
+	rbp_left_set(a_type, a_field, rbp_i_p, (a_node));		\
+    }									\
+    /* Update the root and make sure that it is black.                */\
+    (a_tree)->rbt_root = rbp_left_get(a_type, a_field, &rbp_i_s);	\
+    rbp_black_set(a_type, a_field, (a_tree)->rbt_root);			\
+} while (0)
+
+#define	rb_remove(a_type, a_field, a_cmp, a_tree, a_node) do {		\
+    a_type rbp_r_s;							\
+    a_type *rbp_r_p, *rbp_r_c, *rbp_r_xp, *rbp_r_t, *rbp_r_u;		\
+    int rbp_r_cmp;							\
+    rbp_left_set(a_type, a_field, &rbp_r_s, (a_tree)->rbt_root);	\
+    rbp_right_set(a_type, a_field, &rbp_r_s, &(a_tree)->rbt_nil);	\
+    rbp_black_set(a_type, a_field, &rbp_r_s);				\
+    rbp_r_p = &rbp_r_s;							\
+    rbp_r_c = (a_tree)->rbt_root;					\
+    rbp_r_xp = &(a_tree)->rbt_nil;					\
+    /* Iterate down the tree, but always transform 2-nodes to 3- or   */\
+    /* 4-nodes in order to maintain the invariant that the current    */\
+    /* node is not a 2-node.  This allows simple deletion once a leaf */\
+    /* is reached.  Handle the root specially though, since there may */\
+    /* be no way to convert it from a 2-node to a 3-node.             */\
+    rbp_r_cmp = (a_cmp)((a_node), rbp_r_c);				\
+    if (rbp_r_cmp < 0) {						\
+	rbp_r_t = rbp_left_get(a_type, a_field, rbp_r_c);		\
+	rbp_r_u = rbp_left_get(a_type, a_field, rbp_r_t);		\
+	if (rbp_red_get(a_type, a_field, rbp_r_t) == false		\
+	  && rbp_red_get(a_type, a_field, rbp_r_u) == false) {		\
+	    /* Apply standard transform to prepare for left move.     */\
+	    rbp_move_red_left(a_type, a_field, rbp_r_c, rbp_r_t);	\
+	    rbp_black_set(a_type, a_field, rbp_r_t);			\
+	    rbp_left_set(a_type, a_field, rbp_r_p, rbp_r_t);		\
+	    rbp_r_c = rbp_r_t;						\
+	} else {							\
+	    /* Move left.                                             */\
+	    rbp_r_p = rbp_r_c;						\
+	    rbp_r_c = rbp_left_get(a_type, a_field, rbp_r_c);		\
+	}								\
+    } else {								\
+	if (rbp_r_cmp == 0) {						\
+	    assert((a_node) == rbp_r_c);				\
+	    if (rbp_right_get(a_type, a_field, rbp_r_c)			\
+	      == &(a_tree)->rbt_nil) {					\
+		/* Delete root node (which is also a leaf node).      */\
+		if (rbp_left_get(a_type, a_field, rbp_r_c)		\
+		  != &(a_tree)->rbt_nil) {				\
+		    rbp_lean_right(a_type, a_field, rbp_r_c, rbp_r_t);	\
+		    rbp_right_set(a_type, a_field, rbp_r_t,		\
+		      &(a_tree)->rbt_nil);				\
+		} else {						\
+		    rbp_r_t = &(a_tree)->rbt_nil;			\
+		}							\
+		rbp_left_set(a_type, a_field, rbp_r_p, rbp_r_t);	\
+	    } else {							\
+		/* This is the node we want to delete, but we will    */\
+		/* instead swap it with its successor and delete the  */\
+		/* successor.  Record enough information to do the    */\
+		/* swap later.  rbp_r_xp is the a_node's parent.      */\
+		rbp_r_xp = rbp_r_p;					\
+		rbp_r_cmp = 1; /* Note that deletion is incomplete.   */\
+	    }								\
+	}								\
+	if (rbp_r_cmp == 1) {						\
+	    if (rbp_red_get(a_type, a_field, rbp_left_get(a_type,	\
+	      a_field, rbp_right_get(a_type, a_field, rbp_r_c)))	\
+	      == false) {						\
+		rbp_r_t = rbp_left_get(a_type, a_field, rbp_r_c);	\
+		if (rbp_red_get(a_type, a_field, rbp_r_t)) {		\
+		    /* Standard transform.                            */\
+		    rbp_move_red_right(a_type, a_field, rbp_r_c,	\
+		      rbp_r_t);						\
+		} else {						\
+		    /* Root-specific transform.                       */\
+		    rbp_red_set(a_type, a_field, rbp_r_c);		\
+		    rbp_r_u = rbp_left_get(a_type, a_field, rbp_r_t);	\
+		    if (rbp_red_get(a_type, a_field, rbp_r_u)) {	\
+			rbp_black_set(a_type, a_field, rbp_r_u);	\
+			rbp_rotate_right(a_type, a_field, rbp_r_c,	\
+			  rbp_r_t);					\
+			rbp_rotate_left(a_type, a_field, rbp_r_c,	\
+			  rbp_r_u);					\
+			rbp_right_set(a_type, a_field, rbp_r_t,		\
+			  rbp_r_u);					\
+		    } else {						\
+			rbp_red_set(a_type, a_field, rbp_r_t);		\
+			rbp_rotate_left(a_type, a_field, rbp_r_c,	\
+			  rbp_r_t);					\
+		    }							\
+		}							\
+		rbp_left_set(a_type, a_field, rbp_r_p, rbp_r_t);	\
+		rbp_r_c = rbp_r_t;					\
+	    } else {							\
+		/* Move right.                                        */\
+		rbp_r_p = rbp_r_c;					\
+		rbp_r_c = rbp_right_get(a_type, a_field, rbp_r_c);	\
+	    }								\
+	}								\
+    }									\
+    if (rbp_r_cmp != 0) {						\
+	while (true) {							\
+	    assert(rbp_r_p != &(a_tree)->rbt_nil);			\
+	    rbp_r_cmp = (a_cmp)((a_node), rbp_r_c);			\
+	    if (rbp_r_cmp < 0) {					\
+		rbp_r_t = rbp_left_get(a_type, a_field, rbp_r_c);	\
+		if (rbp_r_t == &(a_tree)->rbt_nil) {			\
+		    /* rbp_r_c now refers to the successor node to    */\
+		    /* relocate, and rbp_r_xp/a_node refer to the     */\
+		    /* context for the relocation.                    */\
+		    if (rbp_left_get(a_type, a_field, rbp_r_xp)		\
+		      == (a_node)) {					\
+			rbp_left_set(a_type, a_field, rbp_r_xp,		\
+			  rbp_r_c);					\
+		    } else {						\
+			assert(rbp_right_get(a_type, a_field,		\
+			  rbp_r_xp) == (a_node));			\
+			rbp_right_set(a_type, a_field, rbp_r_xp,	\
+			  rbp_r_c);					\
+		    }							\
+		    rbp_left_set(a_type, a_field, rbp_r_c,		\
+		      rbp_left_get(a_type, a_field, (a_node)));		\
+		    rbp_right_set(a_type, a_field, rbp_r_c,		\
+		      rbp_right_get(a_type, a_field, (a_node)));	\
+		    rbp_color_set(a_type, a_field, rbp_r_c,		\
+		      rbp_red_get(a_type, a_field, (a_node)));		\
+		    if (rbp_left_get(a_type, a_field, rbp_r_p)		\
+		      == rbp_r_c) {					\
+			rbp_left_set(a_type, a_field, rbp_r_p,		\
+			  &(a_tree)->rbt_nil);				\
+		    } else {						\
+			assert(rbp_right_get(a_type, a_field, rbp_r_p)	\
+			  == rbp_r_c);					\
+			rbp_right_set(a_type, a_field, rbp_r_p,		\
+			  &(a_tree)->rbt_nil);				\
+		    }							\
+		    break;						\
+		}							\
+		rbp_r_u = rbp_left_get(a_type, a_field, rbp_r_t);	\
+		if (rbp_red_get(a_type, a_field, rbp_r_t) == false	\
+		  && rbp_red_get(a_type, a_field, rbp_r_u) == false) {	\
+		    rbp_move_red_left(a_type, a_field, rbp_r_c,		\
+		      rbp_r_t);						\
+		    if (rbp_left_get(a_type, a_field, rbp_r_p)		\
+		      == rbp_r_c) {					\
+			rbp_left_set(a_type, a_field, rbp_r_p, rbp_r_t);\
+		    } else {						\
+			rbp_right_set(a_type, a_field, rbp_r_p,		\
+			  rbp_r_t);					\
+		    }							\
+		    rbp_r_c = rbp_r_t;					\
+		} else {						\
+		    rbp_r_p = rbp_r_c;					\
+		    rbp_r_c = rbp_left_get(a_type, a_field, rbp_r_c);	\
+		}							\
+	    } else {							\
+		/* Check whether to delete this node (it has to be    */\
+		/* the correct node and a leaf node).                 */\
+		if (rbp_r_cmp == 0) {					\
+		    assert((a_node) == rbp_r_c);			\
+		    if (rbp_right_get(a_type, a_field, rbp_r_c)		\
+		      == &(a_tree)->rbt_nil) {				\
+			/* Delete leaf node.                          */\
+			if (rbp_left_get(a_type, a_field, rbp_r_c)	\
+			  != &(a_tree)->rbt_nil) {			\
+			    rbp_lean_right(a_type, a_field, rbp_r_c,	\
+			      rbp_r_t);					\
+			    rbp_right_set(a_type, a_field, rbp_r_t,	\
+			      &(a_tree)->rbt_nil);			\
+			} else {					\
+			    rbp_r_t = &(a_tree)->rbt_nil;		\
+			}						\
+			if (rbp_left_get(a_type, a_field, rbp_r_p)	\
+			  == rbp_r_c) {					\
+			    rbp_left_set(a_type, a_field, rbp_r_p,	\
+			      rbp_r_t);					\
+			} else {					\
+			    rbp_right_set(a_type, a_field, rbp_r_p,	\
+			      rbp_r_t);					\
+			}						\
+			break;						\
+		    } else {						\
+			/* This is the node we want to delete, but we */\
+			/* will instead swap it with its successor    */\
+			/* and delete the successor.  Record enough   */\
+			/* information to do the swap later.          */\
+			/* rbp_r_xp is a_node's parent.               */\
+			rbp_r_xp = rbp_r_p;				\
+		    }							\
+		}							\
+		rbp_r_t = rbp_right_get(a_type, a_field, rbp_r_c);	\
+		rbp_r_u = rbp_left_get(a_type, a_field, rbp_r_t);	\
+		if (rbp_red_get(a_type, a_field, rbp_r_u) == false) {	\
+		    rbp_move_red_right(a_type, a_field, rbp_r_c,	\
+		      rbp_r_t);						\
+		    if (rbp_left_get(a_type, a_field, rbp_r_p)		\
+		      == rbp_r_c) {					\
+			rbp_left_set(a_type, a_field, rbp_r_p, rbp_r_t);\
+		    } else {						\
+			rbp_right_set(a_type, a_field, rbp_r_p,		\
+			  rbp_r_t);					\
+		    }							\
+		    rbp_r_c = rbp_r_t;					\
+		} else {						\
+		    rbp_r_p = rbp_r_c;					\
+		    rbp_r_c = rbp_right_get(a_type, a_field, rbp_r_c);	\
+		}							\
+	    }								\
+	}								\
+    }									\
+    /* Update root.                                                   */\
+    (a_tree)->rbt_root = rbp_left_get(a_type, a_field, &rbp_r_s);	\
+} while (0)
+
+/*
+ * The rb_wrap() macro provides a convenient way to wrap functions around the
+ * cpp macros.  The main benefits of wrapping are that 1) repeated macro
+ * expansion can cause code bloat, especially for rb_{insert,remove)(), and
+ * 2) type, linkage, comparison functions, etc. need not be specified at every
+ * call point.
+ */
+
+#define	rb_wrap(a_attr, a_prefix, a_tree_type, a_type, a_field, a_cmp)	\
+a_attr void								\
+a_prefix##new(a_tree_type *tree) {					\
+    rb_new(a_type, a_field, tree);					\
+}									\
+a_attr a_type *								\
+a_prefix##first(a_tree_type *tree) {					\
+    a_type *ret;							\
+    rb_first(a_type, a_field, tree, ret);				\
+    return (ret);							\
+}									\
+a_attr a_type *								\
+a_prefix##last(a_tree_type *tree) {					\
+    a_type *ret;							\
+    rb_last(a_type, a_field, tree, ret);				\
+    return (ret);							\
+}									\
+a_attr a_type *								\
+a_prefix##next(a_tree_type *tree, a_type *node) {			\
+    a_type *ret;							\
+    rb_next(a_type, a_field, a_cmp, tree, node, ret);			\
+    return (ret);							\
+}									\
+a_attr a_type *								\
+a_prefix##prev(a_tree_type *tree, a_type *node) {			\
+    a_type *ret;							\
+    rb_prev(a_type, a_field, a_cmp, tree, node, ret);			\
+    return (ret);							\
+}									\
+a_attr a_type *								\
+a_prefix##search(a_tree_type *tree, a_type *key) {			\
+    a_type *ret;							\
+    rb_search(a_type, a_field, a_cmp, tree, key, ret);			\
+    return (ret);							\
+}									\
+a_attr a_type *								\
+a_prefix##nsearch(a_tree_type *tree, a_type *key) {			\
+    a_type *ret;							\
+    rb_nsearch(a_type, a_field, a_cmp, tree, key, ret);			\
+    return (ret);							\
+}									\
+a_attr a_type *								\
+a_prefix##psearch(a_tree_type *tree, a_type *key) {			\
+    a_type *ret;							\
+    rb_psearch(a_type, a_field, a_cmp, tree, key, ret);			\
+    return (ret);							\
+}									\
+a_attr void								\
+a_prefix##insert(a_tree_type *tree, a_type *node) {			\
+    rb_insert(a_type, a_field, a_cmp, tree, node);			\
+}									\
+a_attr void								\
+a_prefix##remove(a_tree_type *tree, a_type *node) {			\
+    rb_remove(a_type, a_field, a_cmp, tree, node);			\
+}
+
+/*
+ * The iterators simulate recursion via an array of pointers that store the
+ * current path.  This is critical to performance, since a series of calls to
+ * rb_{next,prev}() would require time proportional to (n lg n), whereas this
+ * implementation only requires time proportional to (n).
+ *
+ * Since the iterators cache a path down the tree, any tree modification may
+ * cause the cached path to become invalid.  In order to continue iteration,
+ * use something like the following sequence:
+ *
+ *   {
+ *       a_type *node, *tnode;
+ *
+ *       rb_foreach_begin(a_type, a_field, a_tree, node) {
+ *           ...
+ *           rb_next(a_type, a_field, a_cmp, a_tree, node, tnode);
+ *           rb_remove(a_type, a_field, a_cmp, a_tree, node);
+ *           rb_foreach_next(a_type, a_field, a_cmp, a_tree, tnode);
+ *           ...
+ *       } rb_foreach_end(a_type, a_field, a_tree, node)
+ *   }
+ *
+ * Note that this idiom is not advised if every iteration modifies the tree,
+ * since in that case there is no algorithmic complexity improvement over a
+ * series of rb_{next,prev}() calls, thus making the setup overhead wasted
+ * effort.
+ */
+
+#define	rb_foreach_begin(a_type, a_field, a_tree, a_var) {		\
+    /* Compute the maximum possible tree depth (3X the black height). */\
+    unsigned rbp_f_height;						\
+    rbp_black_height(a_type, a_field, a_tree, rbp_f_height);		\
+    rbp_f_height *= 3;							\
+    {									\
+	/* Initialize the path to contain the left spine.             */\
+	a_type *rbp_f_path[rbp_f_height];				\
+	a_type *rbp_f_node;						\
+	bool rbp_f_synced = false;					\
+	unsigned rbp_f_depth = 0;					\
+	if ((a_tree)->rbt_root != &(a_tree)->rbt_nil) {			\
+	    rbp_f_path[rbp_f_depth] = (a_tree)->rbt_root;		\
+	    rbp_f_depth++;						\
+	    while ((rbp_f_node = rbp_left_get(a_type, a_field,		\
+	      rbp_f_path[rbp_f_depth-1])) != &(a_tree)->rbt_nil) {	\
+		rbp_f_path[rbp_f_depth] = rbp_f_node;			\
+		rbp_f_depth++;						\
+	    }								\
+	}								\
+	/* While the path is non-empty, iterate.                      */\
+	while (rbp_f_depth > 0) {					\
+	    (a_var) = rbp_f_path[rbp_f_depth-1];
+
+/* Only use if modifying the tree during iteration. */
+#define	rb_foreach_next(a_type, a_field, a_cmp, a_tree, a_node)		\
+	    /* Re-initialize the path to contain the path to a_node.  */\
+	    rbp_f_depth = 0;						\
+	    if (a_node != NULL) {					\
+		if ((a_tree)->rbt_root != &(a_tree)->rbt_nil) {		\
+		    rbp_f_path[rbp_f_depth] = (a_tree)->rbt_root;	\
+		    rbp_f_depth++;					\
+		    rbp_f_node = rbp_f_path[0];				\
+		    while (true) {					\
+			int rbp_f_cmp = (a_cmp)((a_node),		\
+			  rbp_f_path[rbp_f_depth-1]);			\
+			if (rbp_f_cmp < 0) {				\
+			    rbp_f_node = rbp_left_get(a_type, a_field,	\
+			      rbp_f_path[rbp_f_depth-1]);		\
+			} else if (rbp_f_cmp > 0) {			\
+			    rbp_f_node = rbp_right_get(a_type, a_field,	\
+			      rbp_f_path[rbp_f_depth-1]);		\
+			} else {					\
+			    break;					\
+			}						\
+			assert(rbp_f_node != &(a_tree)->rbt_nil);	\
+			rbp_f_path[rbp_f_depth] = rbp_f_node;		\
+			rbp_f_depth++;					\
+		    }							\
+		}							\
+	    }								\
+	    rbp_f_synced = true;
+
+#define	rb_foreach_end(a_type, a_field, a_tree, a_var)			\
+	    if (rbp_f_synced) {						\
+		rbp_f_synced = false;					\
+		continue;						\
+	    }								\
+	    /* Find the successor.                                    */\
+	    if ((rbp_f_node = rbp_right_get(a_type, a_field,		\
+	      rbp_f_path[rbp_f_depth-1])) != &(a_tree)->rbt_nil) {	\
+	        /* The successor is the left-most node in the right   */\
+		/* subtree.                                           */\
+		rbp_f_path[rbp_f_depth] = rbp_f_node;			\
+		rbp_f_depth++;						\
+		while ((rbp_f_node = rbp_left_get(a_type, a_field,	\
+		  rbp_f_path[rbp_f_depth-1])) != &(a_tree)->rbt_nil) {	\
+		    rbp_f_path[rbp_f_depth] = rbp_f_node;		\
+		    rbp_f_depth++;					\
+		}							\
+	    } else {							\
+		/* The successor is above the current node.  Unwind   */\
+		/* until a left-leaning edge is removed from the      */\
+		/* path, or the path is empty.                        */\
+		for (rbp_f_depth--; rbp_f_depth > 0; rbp_f_depth--) {	\
+		    if (rbp_left_get(a_type, a_field,			\
+		      rbp_f_path[rbp_f_depth-1])			\
+		      == rbp_f_path[rbp_f_depth]) {			\
+			break;						\
+		    }							\
+		}							\
+	    }								\
+	}								\
+    }									\
+}
+
+#define	rb_foreach_reverse_begin(a_type, a_field, a_tree, a_var) {	\
+    /* Compute the maximum possible tree depth (3X the black height). */\
+    unsigned rbp_fr_height;						\
+    rbp_black_height(a_type, a_field, a_tree, rbp_fr_height);		\
+    rbp_fr_height *= 3;							\
+    {									\
+	/* Initialize the path to contain the right spine.            */\
+	a_type *rbp_fr_path[rbp_fr_height];				\
+	a_type *rbp_fr_node;						\
+	bool rbp_fr_synced = false;					\
+	unsigned rbp_fr_depth = 0;					\
+	if ((a_tree)->rbt_root != &(a_tree)->rbt_nil) {			\
+	    rbp_fr_path[rbp_fr_depth] = (a_tree)->rbt_root;		\
+	    rbp_fr_depth++;						\
+	    while ((rbp_fr_node = rbp_right_get(a_type, a_field,	\
+	      rbp_fr_path[rbp_fr_depth-1])) != &(a_tree)->rbt_nil) {	\
+		rbp_fr_path[rbp_fr_depth] = rbp_fr_node;		\
+		rbp_fr_depth++;						\
+	    }								\
+	}								\
+	/* While the path is non-empty, iterate.                      */\
+	while (rbp_fr_depth > 0) {					\
+	    (a_var) = rbp_fr_path[rbp_fr_depth-1];
+
+/* Only use if modifying the tree during iteration. */
+#define	rb_foreach_reverse_prev(a_type, a_field, a_cmp, a_tree, a_node)	\
+	    /* Re-initialize the path to contain the path to a_node.  */\
+	    rbp_fr_depth = 0;						\
+	    if (a_node != NULL) {					\
+		if ((a_tree)->rbt_root != &(a_tree)->rbt_nil) {		\
+		    rbp_fr_path[rbp_fr_depth] = (a_tree)->rbt_root;	\
+		    rbp_fr_depth++;					\
+		    rbp_fr_node = rbp_fr_path[0];			\
+		    while (true) {					\
+			int rbp_fr_cmp = (a_cmp)((a_node),		\
+			  rbp_fr_path[rbp_fr_depth-1]);			\
+			if (rbp_fr_cmp < 0) {				\
+			    rbp_fr_node = rbp_left_get(a_type, a_field,	\
+			      rbp_fr_path[rbp_fr_depth-1]);		\
+			} else if (rbp_fr_cmp > 0) {			\
+			    rbp_fr_node = rbp_right_get(a_type, a_field,\
+			      rbp_fr_path[rbp_fr_depth-1]);		\
+			} else {					\
+			    break;					\
+			}						\
+			assert(rbp_fr_node != &(a_tree)->rbt_nil);	\
+			rbp_fr_path[rbp_fr_depth] = rbp_fr_node;	\
+			rbp_fr_depth++;					\
+		    }							\
+		}							\
+	    }								\
+	    rbp_fr_synced = true;
+
+#define	rb_foreach_reverse_end(a_type, a_field, a_tree, a_var)		\
+	    if (rbp_fr_synced) {					\
+		rbp_fr_synced = false;					\
+		continue;						\
+	    }								\
+	    if (rbp_fr_depth == 0) {					\
+		/* rb_foreach_reverse_sync() was called with a NULL   */\
+		/* a_node.                                            */\
+		break;							\
+	    }								\
+	    /* Find the predecessor.                                  */\
+	    if ((rbp_fr_node = rbp_left_get(a_type, a_field,		\
+	      rbp_fr_path[rbp_fr_depth-1])) != &(a_tree)->rbt_nil) {	\
+	        /* The predecessor is the right-most node in the left */\
+		/* subtree.                                           */\
+		rbp_fr_path[rbp_fr_depth] = rbp_fr_node;		\
+		rbp_fr_depth++;						\
+		while ((rbp_fr_node = rbp_right_get(a_type, a_field,	\
+		  rbp_fr_path[rbp_fr_depth-1])) != &(a_tree)->rbt_nil) {\
+		    rbp_fr_path[rbp_fr_depth] = rbp_fr_node;		\
+		    rbp_fr_depth++;					\
+		}							\
+	    } else {							\
+		/* The predecessor is above the current node.  Unwind */\
+		/* until a right-leaning edge is removed from the     */\
+		/* path, or the path is empty.                        */\
+		for (rbp_fr_depth--; rbp_fr_depth > 0; rbp_fr_depth--) {\
+		    if (rbp_right_get(a_type, a_field,			\
+		      rbp_fr_path[rbp_fr_depth-1])			\
+		      == rbp_fr_path[rbp_fr_depth]) {			\
+			break;						\
+		    }							\
+		}							\
+	    }								\
+	}								\
+    }									\
+}
+
+#endif /* RB_H_ */




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