Date: Wed, 11 Nov 2015 10:54:46 -0500
From: Johannes Weiner <hannes@cmpxchg.org>
To: mhocko@kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Andrea Arcangeli <aarcange@redhat.com>, Mel Gorman <mgorman@suse.de>,
        David Rientjes <rientjes@google.com>, linux-mm@kvack.org,
        LKML <linux-kernel@vger.kernel.org>, Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH] mm, oom: Give __GFP_NOFAIL allocations access to memory
 reserves
Message-ID: <20151111155446.GA24431@cmpxchg.org>
References: <1447249697-13380-1-git-send-email-mhocko@kernel.org>
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On Wed, Nov 11, 2015 at 02:48:17PM +0100, mhocko@kernel.org wrote:
> From: Michal Hocko <mhocko@suse.com>
> 
> __GFP_NOFAIL is a big hammer used to ensure that the allocation
> request can never fail. This is a strong requirement and as such
> it also deserves a special treatment when the system is OOM. The
> primary problem here is that the allocation request might have
> come with some locks held and the oom victim might be blocked
> on the same locks. This is basically an OOM deadlock situation.
> 
> This patch tries to reduce the risk of such a deadlocks by giving
> __GFP_NOFAIL allocations a special treatment and let them dive into
> memory reserves after oom killer invocation. This should help them
> to make a progress and release resources they are holding. The OOM
> victim should compensate for the reserves consumption.
> 
> Signed-off-by: Michal Hocko <mhocko@suse.com>
> ---
> 
> Hi,
> this has been posted previously as a part of larger GFP_NOFS related
> patch set (http://lkml.kernel.org/r/1438768284-30927-1-git-send-email-mhocko%40kernel.org)
> but Andrea was asking basically the same thing at LSF early this year
> (I cannot seem to find it in any public archive though). I think the
> patch makes some sense on its own.

I sent this right after LSF based on Andrea's suggestion:

https://lkml.org/lkml/2015/3/25/37
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