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From Greg Ames <grega...@apache.org>
Subject Re: [PATCH] the mmap problem
Date Fri, 22 Nov 2002 16:35:44 GMT
Cliff Woolley wrote:
> This patch should address the mmap problems.  What it does is ditch the
> ownership flag and replace it with something resembling a reference count.
> It's not actually a refcount because .. where would you store the
> refcount?  I talked with a few of the guys about that possibility but
> everything we came up with was kind of ugly.  So an alternative that
> somebody (Sander?) came up with 

yep, it was Sander's great idea

>                                  was to put all of the dup'ed apr_mmap_t's
> that refer to the same mmap'ed region in a ring with each other... that
> way you don't have to have a single centralized location for the refcount
> and you don't have lifetime issues to worry about anymore.
> 
> Greg Ames did some testing on this and says it looks good as far as he can
> tell... additional eyes would be appreciated.

in case anyone cares, here's what I did:

* built httpd with Electric Fence + my core_output_filter patch to drive 
cleanups before the end of a keepalive connection.  Ran the mod_include test 
case Jeff came up with that execs a script.  It works as expected now.

* stepped thru the scenario above with gdb looking for weird stuff.  Didn't find 
any.

* ran a log replay against it, mostly without EFence since it eats so much CPU 
under load.  That worked fine too.

So +1 here.

Greg





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