From: Michal Hocko <mhocko@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
David Rientjes <rientjes@google.com>,
Oleg Nesterov <oleg@redhat.com>,
Vladimir Davydov <vdavydov@parallels.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 10/10] mm, oom: hide mm which is shared with kthread or global init
Date: Wed, 20 Jul 2016 08:29:12 +0200 [thread overview]
Message-ID: <20160720062912.GA11249@dhcp22.suse.cz> (raw)
In-Reply-To: <20160719162759.e391c685db7a8de30b79320c@linux-foundation.org>
On Tue 19-07-16 16:27:59, Andrew Morton wrote:
> On Tue, 19 Jul 2016 14:05:39 +0200 Michal Hocko <mhocko@kernel.org> wrote:
>
> > > After this patch we should guarantee a forward progress for the OOM
> > > killer even when the selected victim is sharing memory with a kernel
> > > thread or global init.
> >
> > Could you replace the last two paragraphs with the following. Tetsuo
> > didn't like the guarantee mentioned there because that is a too strong
> > statement as find_lock_task_mm might not find any mm and so we still
> > could end up looping on the oom victim if it gets stuck somewhere in
> > __mmput. This particular patch didn't aim at closing that case. Plugging
> > that hole is planned later after the next upcoming merge window closes.
> >
> > "
> > In order to help a forward progress for the OOM killer, make sure
> > that this really rare cases will not get into the way and hide
> > the mm from the oom killer by setting MMF_OOM_REAPED flag for it.
> > oom_scan_process_thread will ignore any TIF_MEMDIE task if it has
> > MMF_OOM_REAPED flag set to catch these oom victims.
> >
> > After this patch we should guarantee a forward progress for the OOM
> > killer even when the selected victim is sharing memory with a kernel
> > thread or global init as long as the victims mm is still alive.
> > "
>
> I tweaked it a bit:
>
> : In order to help forward progress for the OOM killer, make sure that
> : this really rare case will not get in the way - we do this by hiding
> : the mm from the oom killer by setting MMF_OOM_REAPED flag for it.
> : oom_scan_process_thread will ignore any TIF_MEMDIE task if it has
> : MMF_OOM_REAPED flag set to catch these oom victims.
> :
> : After this patch we should guarantee forward progress for the OOM
> : killer even when the selected victim is sharing memory with a kernel
> : thread or global init as long as the victims mm is still alive.
Sounds good to me. Thanks!
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2016-07-20 6:29 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-20 12:43 [PATCH 0/10 -v5] Handle oom bypass more gracefully Michal Hocko
2016-06-20 12:43 ` [PATCH 01/10] proc, oom: drop bogus task_lock and mm check Michal Hocko
2016-06-20 12:43 ` [PATCH 02/10] proc, oom: drop bogus sighand lock Michal Hocko
2016-06-20 12:43 ` [PATCH 03/10] proc, oom_adj: extract oom_score_adj setting into a helper Michal Hocko
2016-06-20 12:43 ` [PATCH 04/10] mm, oom_adj: make sure processes sharing mm have same view of oom_score_adj Michal Hocko
2016-06-20 12:43 ` [PATCH 05/10] mm, oom: skip vforked tasks from being selected Michal Hocko
2016-06-20 12:43 ` [PATCH 06/10] mm, oom: kill all tasks sharing the mm Michal Hocko
2016-06-20 12:43 ` [PATCH 07/10] mm, oom: fortify task_will_free_mem Michal Hocko
2016-06-20 12:43 ` [PATCH 08/10] mm, oom: task_will_free_mem should skip oom_reaped tasks Michal Hocko
2016-06-20 12:43 ` [PATCH 09/10] mm, oom_reaper: do not attempt to reap a task more than twice Michal Hocko
2016-06-20 12:43 ` [PATCH 10/10] mm, oom: hide mm which is shared with kthread or global init Michal Hocko
2016-07-19 12:05 ` Michal Hocko
2016-07-19 23:27 ` Andrew Morton
2016-07-20 6:29 ` Michal Hocko [this message]
-- strict thread matches above, loose matches on Subject: below --
2016-06-09 11:52 [PATCH 0/10 -v4] Handle oom bypass more gracefully Michal Hocko
2016-06-09 11:52 ` [PATCH 10/10] mm, oom: hide mm which is shared with kthread or global init Michal Hocko
2016-06-09 15:15 ` Tetsuo Handa
2016-06-09 15:41 ` Michal Hocko
2016-06-16 13:15 ` Tetsuo Handa
2016-06-16 13:36 ` Tetsuo Handa
2016-06-15 14:37 ` Oleg Nesterov
2016-06-16 6:31 ` Michal Hocko
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