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

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Message-ID: <alpine.DEB.2.10.1606081549490.12203@chino.kir.corp.google.com>
Date:	Wed, 8 Jun 2016 15:51:20 -0700 (PDT)
From:	David Rientjes <rientjes@...gle.com>
To:	Michal Hocko <mhocko@...nel.org>
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, 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.