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Date: Thu, 6 Mar 2014 16:12:46 -0500
From: Tejun Heo <tj@kernel.org>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Johannes Weiner <hannes@cmpxchg.org>, Michal Hocko <mhocko@suse.cz>,
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        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
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Subject: Re: [patch 07/11] mm, memcg: allow processes handling oom
 notifications to access reserves
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On Tue, Mar 04, 2014 at 07:59:29PM -0800, David Rientjes wrote:
> Now that a per-process flag is available, define it for processes that
> handle userspace oom notifications.  This is an optimization to avoid
> mantaining a list of such processes attached to a memcg at any given time
> and iterating it at charge time.
> 
> This flag gets set whenever a process has registered for an oom
> notification and is cleared whenever it unregisters.
> 
> When memcg reclaim has failed to free any memory, it is necessary for
> userspace oom handlers to be able to dip into reserves to pagefault text,
> allocate kernel memory to read the "tasks" file, allocate heap, etc.
> 
> System oom conditions are not addressed at this time, but the same per-
> process flag can be used in the page allocator to determine if access
> should be given to userspace oom handlers to per-zone memory reserves at
> a later time once there is consensus.
> 
> Signed-off-by: David Rientjes <rientjes@google.com>

ntil consensus on the whole approach can be reached,

 Nacked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun