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From: Andrew Morton <akpm@linux-foundation.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
	mm-commits@vger.kernel.org, penguin-kernel@i-love.sakura.ne.jp,
	cgroups@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: + memcg-do-not-report-racy-no-eligible-oom-tasks.patch added to -mm tree
Date: Mon, 28 Jan 2019 10:26:16 -0800	[thread overview]
Message-ID: <20190128102616.d7d63f8e1ecdf176bc313f8a@linux-foundation.org> (raw)
In-Reply-To: <20190125172416.GB20411@dhcp22.suse.cz>

On Fri, 25 Jan 2019 18:24:16 +0100 Michal Hocko <mhocko@kernel.org> wrote:

> > >     out_of_memory
> > >       select_bad_process # no task
> > > 
> > > If Thread1 didn't race it would bail out from try_charge and force the
> > > charge.  We can achieve the same by checking tsk_is_oom_victim inside the
> > > oom_lock and therefore close the race.
> > > 
> > > [1] http://lkml.kernel.org/r/bb2074c0-34fe-8c2c-1c7d-db71338f1e7f@i-love.sakura.ne.jp
> > > Link: http://lkml.kernel.org/r/20190107143802.16847-3-mhocko@kernel.org
> > > Signed-off-by: Michal Hocko <mhocko@suse.com>
> > > Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> > > Cc: Johannes Weiner <hannes@cmpxchg.org>
> > > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > 
> > It looks like this problem is happening in production systems:
> > 
> > https://www.spinics.net/lists/cgroups/msg21268.html
> > 
> > where the threads don't exit because they are trapped writing out the
> > oom messages to a slow console (running the reproducer from this email
> > thread triggers the oom flooding).
> > 
> > So IMO we should put this into 5.0 and add:
> 
> Please note that Tetsuo has found out that this will not work with the
> CLONE_VM without CLONE_SIGHAND cases and his http://lkml.kernel.org/r/01370f70-e1f6-ebe4-b95e-0df21a0bc15e@i-love.sakura.ne.jp
> should handle this case as well. I've only had objections to the
> changelog but other than that the patch looked sensible to me.

So I think you're saying that 

mm-oom-marks-all-killed-tasks-as-oom-victims.patch
and
memcg-do-not-report-racy-no-eligible-oom-tasks.patch

should be dropped and that "[PATCH v2] memcg: killed threads should not
invoke memcg OOM killer" should be redone with some changelog
alterations and should be merged instead?


  parent reply	other threads:[~2019-01-28 18:26 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190109190306.rATpT%akpm@linux-foundation.org>
2019-01-25 16:56 ` + memcg-do-not-report-racy-no-eligible-oom-tasks.patch added to -mm tree Johannes Weiner
2019-01-25 17:24   ` Michal Hocko
2019-01-25 18:33     ` Johannes Weiner
2019-01-26  1:09       ` Tetsuo Handa
2019-01-28 18:26     ` Andrew Morton [this message]
2019-01-28 18:43       ` Michal Hocko

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