linux-kernel - Re: [Patch v4 1/2] freezer: check OOM kill while being frozen

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Message-ID: <20140911141051.GK22042@dhcp22.suse.cz>
Date:	Thu, 11 Sep 2014 16:10:51 +0200
From:	Michal Hocko <mhocko@...e.cz>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	Tejun Heo <tj@...nel.org>, Cong Wang <xiyou.wangcong@...il.com>,
	LKML <linux-kernel@...r.kernel.org>,
	David Rientjes <rientjes@...gle.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [Patch v4 1/2] freezer: check OOM kill while being frozen

On Thu 11-09-14 16:26:56, Rafael J. Wysocki wrote:
> On Thursday, September 11, 2014 04:04:48 PM Michal Hocko wrote:
> > On Thu 11-09-14 16:17:56, Rafael J. Wysocki wrote:
> > [...]
> > > And I'm still wondering if the OOM killer may be made avoid killing frozen
> > > tasks.
> > 
> > This is really tricky. OOM killer aims at the biggest memory hog. We
> > shouldn't ignore it just because it hides into the fridge... So even
> > if we "fix" oom killer to ignore frozen tasks (which is inherently
> > racy btw.) then we have a potential problem of freezer abuse (e.g. in
> > container environments). So I strongly believe that the OOM killer has
> > to be able to kill a frozen tasks.
> 
> OK
> 
> Is the OOM killer the only place where TIF_MEMDIE is set?

Yes. To be precise, lowmemorykiller (staging android thingy), global OOM
killer and memcg OOM killer. Any other users would be an abuse.

-- 
Michal Hocko
SUSE Labs
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