From: Michal Hocko <mhocko@kernel.org>
To: David Rientjes <rientjes@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>,
linux-mm@kvack.org,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Vladimir Davydov <vdavydov@parallels.com>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 06/10] mm, oom: kill all tasks sharing the mm
Date: Wed, 8 Jun 2016 08:22:20 +0200 [thread overview]
Message-ID: <20160608062219.GA22570@dhcp22.suse.cz> (raw)
In-Reply-To: <alpine.DEB.2.10.1606071514550.18400@chino.kir.corp.google.com>
On Tue 07-06-16 15:15:37, David Rientjes wrote:
> On Tue, 7 Jun 2016, Oleg Nesterov wrote:
>
> > On 06/06, David Rientjes wrote:
> > >
> > > > There is a potential race where we kill the oom disabled task which is
> > > > highly unlikely but possible. It would happen if __set_oom_adj raced
> > > > with select_bad_process and then it is OK to consider the old value or
> > > > with fork when it should be acceptable as well.
> > > > Let's add a little note to the log so that people would tell us that
> > > > this really happens in the real life and it matters.
> > > >
> > >
> > > We cannot kill oom disabled processes at all, little race or otherwise.
> >
> > But this change doesn't really make it worse?
> >
>
> Why is the patch asking users to report oom killing of a process that
> raced with setting /proc/pid/oom_score_adj to OOM_SCORE_ADJ_MIN? What is
> possibly actionable about it?
Well, the primary point is to know whether such races happen in the real
loads and whether they actually matter. If yes we can harden the locking
or come up with a less racy solutions.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2016-06-08 6:22 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-03 9:16 [PATCH 0/10 -v3] Handle oom bypass more gracefully Michal Hocko
2016-06-03 9:16 ` [PATCH 01/10] proc, oom: drop bogus task_lock and mm check Michal Hocko
2016-06-03 9:16 ` [PATCH 02/10] proc, oom: drop bogus sighand lock Michal Hocko
2016-06-03 9:16 ` [PATCH 03/10] proc, oom_adj: extract oom_score_adj setting into a helper Michal Hocko
2016-06-03 9:16 ` [PATCH 04/10] mm, oom_adj: make sure processes sharing mm have same view of oom_score_adj Michal Hocko
2016-06-03 9:16 ` [PATCH 05/10] mm, oom: skip vforked tasks from being selected Michal Hocko
2016-06-03 9:16 ` [PATCH 06/10] mm, oom: kill all tasks sharing the mm Michal Hocko
2016-06-06 22:27 ` David Rientjes
2016-06-06 23:20 ` Oleg Nesterov
2016-06-07 6:37 ` Michal Hocko
2016-06-07 22:15 ` David Rientjes
2016-06-08 6:22 ` Michal Hocko [this message]
2016-06-08 22:51 ` David Rientjes
2016-06-09 6:46 ` Michal Hocko
2016-06-03 9:16 ` [PATCH 07/10] mm, oom: fortify task_will_free_mem Michal Hocko
2016-06-03 9:16 ` [PATCH 08/10] mm, oom: task_will_free_mem should skip oom_reaped tasks Michal Hocko
2016-06-03 9:16 ` [RFC PATCH 09/10] mm, oom_reaper: do not attempt to reap a task more than twice Michal Hocko
2016-06-03 9:16 ` [RFC PATCH 10/10] mm, oom: hide mm which is shared with kthread or global init Michal Hocko
2016-06-03 15:16 ` Tetsuo Handa
2016-06-06 8:15 ` Michal Hocko
2016-06-06 13:26 ` Michal Hocko
2016-06-07 6:26 ` Michal Hocko
2016-06-03 12:00 ` [PATCH 0/10 -v3] Handle oom bypass more gracefully Tetsuo Handa
2016-06-03 12:20 ` Michal Hocko
2016-06-03 12:22 ` Michal Hocko
2016-06-04 10:57 ` Tetsuo Handa
2016-06-06 8:39 ` Michal Hocko
2016-06-03 15:17 ` Tetsuo Handa
2016-06-06 8:36 ` Michal Hocko
2016-06-07 14:30 ` Tetsuo Handa
2016-06-07 15:05 ` Michal Hocko
2016-06-07 21:49 ` Tetsuo Handa
2016-06-08 7:27 ` Michal Hocko
2016-06-08 14:55 ` Tetsuo Handa
2016-06-08 16:05 ` Michal Hocko
2016-06-09 11:52 [PATCH 0/10 -v4] " Michal Hocko
2016-06-09 11:52 ` [PATCH 06/10] mm, oom: kill all tasks sharing the mm Michal Hocko
2016-06-20 12:43 [PATCH 0/10 -v5] Handle oom bypass more gracefully Michal Hocko
2016-06-20 12:43 ` [PATCH 06/10] mm, oom: kill all tasks sharing the mm Michal Hocko
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