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From: Michal Hocko <mhocko@suse.cz>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: linux-mm@kvack.org, akpm@linux-foundation.org, oleg@redhat.com,
	vdavydov@virtuozzo.com, rientjes@google.com
Subject: Re: [PATCH] mm, oom: fix for hiding mm which is shared with kthreador global init
Date: Tue, 19 Jul 2016 08:40:49 +0200	[thread overview]
Message-ID: <20160719064048.GA9486@dhcp22.suse.cz> (raw)
In-Reply-To: <201607190630.DIH34854.HFOOQFLOJMVFSt@I-love.SAKURA.ne.jp>

On Tue 19-07-16 06:30:42, Tetsuo Handa wrote:
> Michal Hocko wrote:
> > I really do not think that this unlikely case really has to be handled
> > now. We are very likely going to move to a different model of oom victim
> > detection soon. So let's do not add new hacks. exit_oom_victim from
> > oom_kill_process just looks like sand in eyes.
> 
> Then, please revert "mm, oom: hide mm which is shared with kthread or global init"
> ( http://lkml.kernel.org/r/1466426628-15074-11-git-send-email-mhocko@kernel.org ).
> I don't like that patch because it is doing pointless find_lock_task_mm() test
> and is telling a lie because it does not guarantee that we won't hit OOM livelock.

The above patch doesn't make the situation worse wrt livelock. I
consider it an improvement. It adds find_lock_task_mm into
oom_scan_process_thread but that can hardly be worse than just the
task->signal->oom_victims check because we can catch MMF_OOM_REAPED. If
we are mm loss, which is a less likely case, then we behave the same as
with the previous implementation.

So I do not really see a reason to revert that patch for now.

-- 
Michal Hocko
SUSE Labs

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  reply	other threads:[~2016-07-19  6:40 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-16  5:30 [PATCH] mm, oom: fix for hiding mm which is shared with kthread or global init Tetsuo Handa
2016-07-18  7:18 ` Michal Hocko
2016-07-18 21:30   ` [PATCH] mm, oom: fix for hiding mm which is shared with kthreador " Tetsuo Handa
2016-07-19  6:40     ` Michal Hocko [this message]
2016-07-19  9:37       ` Michal Hocko
2016-07-19 10:36         ` [PATCH] mm, oom: fix for hiding mm which is shared with kthread or " Tetsuo Handa
2016-07-19 10:54           ` Michal Hocko
2016-07-19 11:43             ` Tetsuo Handa
2016-07-19 11:58               ` Michal Hocko

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