linux-kernel - Re: [PATCH 0/2] oom, memcg: do not report racy no-eligible OOM

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Message-ID: <e55fb27c-f23b-0ac5-acfd-7265c0a3b8dc@i-love.sakura.ne.jp>
Date:   Wed, 9 Jan 2019 20:34:46 +0900
From:   Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>
To:     Michal Hocko <mhocko@...nel.org>, linux-mm@...ck.org
Cc:     Johannes Weiner <hannes@...xchg.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 0/2] oom, memcg: do not report racy no-eligible OOM

On 2019/01/09 20:03, Michal Hocko wrote:
> Tetsuo,
> can you confirm that these two patches are fixing the issue you have
> reported please?
> 

My patch fixes the issue better than your "[PATCH 2/2] memcg: do not report racy no-eligible OOM tasks" does.

You can post "[PATCH 1/2] mm, oom: marks all killed tasks as oom victims"
based on a report that we needlessly select more OOM victims because
MMF_OOM_SKIP is quickly set by the OOM reaper. In fact, updating
oom_reap_task() / exit_mmap() to use

  mutex_lock(&oom_lock);
  set_bit(MMF_OOM_SKIP, &mm->flags);
  mutex_unlock(&oom_lock);

will mostly close the race as well.