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Date: Fri, 1 Dec 2017 14:33:17 +0000
From: Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH 1/3] mm,oom: Move last second allocation to inside the
 OOM killer.
Message-ID: <20171201143317.GC8097@cmpxchg.org>
References: <1511607169-5084-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp>
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Sender: owner-linux-mm@kvack.org
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To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org, Andrea Arcangeli <aarcange@redhat.com>, Michal Hocko <mhocko@suse.com>

On Sat, Nov 25, 2017 at 07:52:47PM +0900, Tetsuo Handa wrote:
> @@ -1068,6 +1071,17 @@ bool out_of_memory(struct oom_control *oc)
>  	}
>  
>  	select_bad_process(oc);
> +	/*
> +	 * Try really last second allocation attempt after we selected an OOM
> +	 * victim, for somebody might have managed to free memory while we were
> +	 * selecting an OOM victim which can take quite some time.

Somebody might free some memory right after this attempt fails. OOM
can always be a temporary state that resolves on its own.

What keeps us from declaring OOM prematurely is the fact that we
already scanned the entire LRU list without success, not last second
or last-last second, or REALLY last-last-last-second allocations.

Nacked-by: Johannes Weiner <hannes@cmpxchg.org>

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