linux-kernel - Re: [RFC] [PATCH] Cgroup based OOM killer controller

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Message-Id: <200901271638.21720.knikanth@suse.de>
Date:	Tue, 27 Jan 2009 16:38:21 +0530
From:	Nikanth Karthikesan <knikanth@...e.de>
To:	David Rientjes <rientjes@...gle.com>
Cc:	Evgeniy Polyakov <zbr@...emap.net>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	linux-kernel@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Chris Snook <csnook@...hat.com>,
	Arve Hjønnevåg <arve@...roid.com>,
	Paul Menage <menage@...gle.com>,
	containers@...ts.linux-foundation.org,
	Balbir Singh <balbir@...ux.vnet.ibm.com>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Subject: Re: [RFC] [PATCH] Cgroup based OOM killer controller

On Tuesday 27 January 2009 16:23:00 David Rientjes wrote:
> On Tue, 27 Jan 2009, Nikanth Karthikesan wrote:
> > > As previously stated, I think the heuristic to penalize tasks for not
> > > having an intersection with the set of allowable nodes of the oom
> > > triggering task could be made slightly more severe.  That's irrelevant
> > > to your patch, though.
> >
> > But the heuristic makes it non-deterministic, unlike memcg case. And this
> > mandates special handling for cpuset constrained OOM conditions in this
> > patch.
>
> Dividing a badness score by 8 if a task's set of allowable nodes do not
> insect with the oom triggering task's set does not make an otherwise
> deterministic algorithm non-deterministic.
>
> I don't understand what you're arguing for here.  Are you suggesting that
> we should not prefer tasks that intersect the set of allowable nodes?
> That makes no sense if the goal is to allow for future memory freeing.
>

No. Actually I am just wondering, will it be possible to check whether a 
particular task has memory allocated or mmaped from this node to avoid killing 
an innocent task. I compared with memcg, to say that memcg never kills a task 
not related to the memcg constrained oom. Sorry if I was unclear, earlier. If 
we do this, oom-controller will not require special handling for cpuset 
constrained ooms.

Thanks
Nikanth
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