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From Jeff Trawick <traw...@gmail.com>
Subject Re: Building the apr runtime library appropriately for the worker MPM
Date Thu, 04 Apr 2013 00:49:11 GMT
On Wednesday, April 3, 2013, Philip Martin wrote:

> Ben Reser <ben@reser.org <javascript:;>> writes:
>
> > On Wed, Apr 3, 2013 at 12:29 PM, Jeff Trawick <trawick@gmail.com<javascript:;>>
> wrote:
> >> I'm not aware of any apr_file_lock() use within httpd, so you wouldn't
> >> regress anything (unless you're using third-party modules that use
> >> apr_file_lock).  But I guess you've introduced a third-party module that
> >> uses apr_file_lock() or you wouldn't be asking about this?
> >
> > Subversion uses apr_file_lock() and by extension so does mod_dav_svn.
>
> The main place we use this is in the FSFS backend.  On multi-threaded
> Unix systems we also use a mutex to ensure that only a single thread in
> each process locks the file.  So the use of fcntl() should be OK here as
> far as Subversion is concerned.


Cool, but APR needs a fix...

I didn't get a chance to check where if anywhere APR  uses a pthread mutex
in conjunction with fcntl for mutexes...


> There is also a lock for the BDB backend that is only used for certain
> admin operations and those operations have a restriction that the caller
> is responsible for calling the functions in a single-threaded context.
> These functions are used by the single-threaded svnadmin program.
>
> --
> Philip
>


-- 
Born in Roswell... married an alien...
http://emptyhammock.com/

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