Date: Tue, 14 Apr 2009 11:46:04 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Theodore Tso <tytso@mit.edu>
Cc: knikanth@suse.de, jens.axboe@oracle.com, neilb@suse.de,
       linux-kernel@vger.kernel.org, chris.mason@oracle.com,
       shaggy@austin.ibm.com, xfs-masters@oss.sgi.com
Subject: Re: [PATCH 0/6] Handle bio_alloc failure
Message-Id: <20090414114604.2d552cbb.akpm@linux-foundation.org>
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	<20090414111838.GG5178@kernel.dk>
	<200904141711.20378.knikanth@suse.de>
	<20090414181632.GI955@mit.edu>
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On Tue, 14 Apr 2009 14:16:32 -0400
Theodore Tso <tytso@mit.edu> wrote:

> In include/linux/page_alloc.h,
> __GFP_NOFAIL is documented as "will never fail", but it says
> absolutely nothing about __GFP_WAIT.

In the present implementation, a __GFP_WAIT allocation for order <=3
will only fail if the caller was oom-killed.

Which raises the question "what happens when a mempool_alloc() caller
gets oom-killed?".

Seems that it will loop around in mempool_alloc() doing weak attempts
to allocate memory, not doing direct reclaim while waiting for someone
else to free something up.  hm.  I guess it'll recover eventually.

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