linux-kernel - Re: [PATCH 06/10] mm, oom: kill all tasks sharing the mm

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Message-ID: <20160609064634.GC24777@dhcp22.suse.cz>
Date:	Thu, 9 Jun 2016 08:46:35 +0200
From:	Michal Hocko <mhocko@...nel.org>
To:	David Rientjes <rientjes@...gle.com>
Cc:	Oleg Nesterov <oleg@...hat.com>, linux-mm@...ck.org,
	Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>,
	Vladimir Davydov <vdavydov@...allels.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 06/10] mm, oom: kill all tasks sharing the mm

On Wed 08-06-16 15:51:20, David Rientjes wrote:
> On Wed, 8 Jun 2016, Michal Hocko wrote:
> 
> > > 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.
> 
> A thread being set to oom disabled while racing with the oom killer 
> obviously isn't a concern: it could very well be set to oom disabled after 
> the SIGKILL is sent and before the signal is handled, and that's not even 
> fixable without unneeded complexity because we don't know the source of 
> the SIGKILL.  Please remove the printk entirely.

OK, if you find it more confusing than useful I will not insist.

-- 
Michal Hocko
SUSE Labs