[6.0] d285db34b updating vmods should just work (not new in any way)

Dridi Boukelmoune dridi.boukelmoune at gmail.com
Wed Oct 31 13:08:17 UTC 2018

commit d285db34b7b6ff4ca1b3a407dd764f688890af72
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Wed Sep 12 10:29:18 2018 +0200

    updating vmods should just work (not new in any way)
    We copy vmods using unique filenames for ages
    Ref: 3cf587668219166188e0dce304edb0bf8ab346ab
    Original text from 2014: 920541a8fa79b2ce9471571df0f973b1beeb25b8

diff --git a/doc/sphinx/reference/vmod.rst b/doc/sphinx/reference/vmod.rst
index eb35c1bf9..e91b87db1 100644
--- a/doc/sphinx/reference/vmod.rst
+++ b/doc/sphinx/reference/vmod.rst
@@ -610,33 +610,3 @@ unless they access VMOD specific global state, shared with other VCLs.
 Traffic in other VCLs which also import this VMOD, will be happening
 while housekeeping is going on.
-Updating VMODs
-A compiled VMOD is a shared library file which Varnish dlopen(3)'s
-using flags RTLD_NOW | RTLD_LOCAL.
-As a general rule, once a file is opened with dlopen(3) you should
-never modify it, but it is safe to rename it and put a new file
-under the name it had, which is how most tools installs and updates
-shared libraries.
-However, when you call dlopen(3) with the same filename multiple
-times it will give you the same single copy of the shared library
-file, without checking if it was updated in the meantime.
-This is obviously an oversight in the design of the dlopen(3) library
-function, but back in the late 1980s nobody could imagine why a
-program would ever want to have multiple different versions of the
-same shared library mapped at the same time.
-Varnish does that, and therefore you must restart the worker process
-before Varnish will discover an updated VMOD.
-If you want to test a new version of a VMOD, while being able to
-instantly switch back to the old version, you will have to install
-each version with a distinct filename or in a distinct subdirectory
-and use ``import foo from "...";`` to reference it in your VCL.
-We're not happy about this, but have found no sensible workarounds.

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