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RE: svn commit: r1523465 - /subversion/trunk/subversion/svnserve/svnserve.c

From: Bert Huijben <bert_at_qqmail.nl>
Date: Sun, 15 Sep 2013 20:43:43 +0200

Ah, I read the patch too fast.

 

In this snippet

[[

+/* Clear and release the given connection POOL.

+ */

+static void

+release_connection_pool(apr_pool_t *pool)

+{

+ svn_error_t *err;

+ svn_pool_clear(pool);

+

+ err = svn_mutex__lock(connection_pools_mutex);

+ if (err)

+ {

+ svn_error_clear(err);

+ svn_pool_destroy(pool);

+ }

+ else

+ {

+ APR_ARRAY_PUSH(connection_pools, apr_pool_t *) = pool;

+ svn_error_clear(svn_mutex__unlock(connection_pools_mutex,

+ SVN_NO_ERROR));

+ }

+}

+

]]

I automatically assumed the 'svn_pool_clear' was just a variable assignment,
because usually we have a white line before the first real code. instead of
just after the first line.

 

Maybe we should fix the whitespace here to follow our usual layout?

 

                Bert

 

From: Stefan Fuhrmann [mailto:stefan.fuhrmann_at_wandisco.com]
Sent: zondag 15 september 2013 20:25
To: Bert Huijben
Cc: Subversion Development; commits_at_subversion.apache.org
Subject: Re: svn commit: r1523465 -
/subversion/trunk/subversion/svnserve/svnserve.c

 

On Sun, Sep 15, 2013 at 8:07 PM, Bert Huijben <bert_at_qqmail.nl
<mailto:bert_at_qqmail.nl> > wrote:

> -----Original Message-----
> From: stefan2_at_apache.org <mailto:stefan2_at_apache.org>
[mailto:stefan2_at_apache.org <mailto:stefan2_at_apache.org> ]
> Sent: zondag 15 september 2013 19:47
> To: commits_at_subversion.apache.org <mailto:commits_at_subversion.apache.org>
> Subject: svn commit: r1523465 -
> /subversion/trunk/subversion/svnserve/svnserve.c
>
> Author: stefan2
> Date: Sun Sep 15 17:46:36 2013
> New Revision: 1523465
>
> URL: http://svn.apache.org/r1523465
> Log:
> As it turns out, allocating memory from the OS in a multi-threaded
> environment is relatively costly. With APR pools, this happens
> every time we use a newly created root pool.
>
> Therefore, teach svnserve to recycle the connection pools, keeping
> those precious memory blocks allocated instead of disposing and
> re-allocating them.

Is this really the best way to do this?

 

Not sure. I'm open for suggestions.
 

Can't we create a subpool here? (Or do we also need multiple allocators,
etc.)

 

No. Those pools will be used concurrently by their
respective worker threads.

 

In the implementation I see that the existing pools are re-used, but they
are not *cleared* before re-use?

 

release_connection_pool() clears them.

 

Shouldn't we at least release the used memory (and thate) when handing back
the memory to the pool allocator?

 

-- Stefan^2.

 
Received on 2013-09-15 20:44:40 CEST

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