threads looping in PipeSession()

[Poul-Henning Kamp]

In message <48271.213.180.137.172.1190721848.squirrel at micro.fsi.pl>, "Michal Belczyk" writes:
>Hello,
>
>while testing varnish I noticed several threads consuming 100% of the cpu
>time:
>
>shutdown(5221, 1 /* send */)            = 0
>poll([{fd=5221, events=POLLIN|POLLERR}, {fd=5172, events=0,
>revents=POLLHUP}], 2, 60000) = 1

Can you try this patch:

Index: cache_pipe.c
===================================================================
--- cache_pipe.c	(revision 2043)
+++ cache_pipe.c	(working copy)
@@ -45,11 +45,14 @@
 static void
 rdf(struct pollfd *fds, int idx)
 {
-	int i, j;
+	int i, j, rev;
 	char buf[BUFSIZ], *p;
 
-	i = read(fds[idx].fd, buf, sizeof buf);
-	if (i <= 0 || fds[1-idx].events == 0) {
+	rev = fds[idx].revents & POLLHUP;
+	if (!rev)
+		i = read(fds[idx].fd, buf, sizeof buf);
+
+	if (rev || i <= 0 || fds[1-idx].events == 0) {
 		AZ(shutdown(fds[idx].fd, SHUT_RD));
 		AZ(shutdown(fds[1-idx].fd, SHUT_WR));
 		fds[idx].events = 0;


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