linux-kernel - Re: Improving OOM killer

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Message-Id: <201002102229.24448.l.lunak@suse.cz>
Date:	Wed, 10 Feb 2010 22:29:24 +0100
From:	Lubos Lunak <l.lunak@...e.cz>
To:	Rik van Riel <riel@...hat.com>
Cc:	David Rientjes <rientjes@...gle.com>,
	Balbir Singh <balbir@...ux.vnet.ibm.com>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Nick Piggin <npiggin@...e.de>, Jiri Kosina <jkosina@...e.cz>
Subject: Re: Improving OOM killer

On Wednesday 10 of February 2010, Rik van Riel wrote:
> On 02/10/2010 03:54 PM, Lubos Lunak wrote:
> >   Which however can mean that not killing this system daemon will be
> > traded for DoS-ing the whole system, if the daemon keeps spawning new
> > children as soon as the OOM killer frees up resources for them.
>
> Killing the system daemon *is* a DoS.

 Maybe, but if there are two such system daemons on the machine, it's only 
half of the other DoS. And since that system daemon has already been 
identified as a forkbomb, it's probably already useless anyway and killing 
the children won't save anything. In which realistic case a system daemon has 
children that together cause OOM, yet can still be considered working after 
you kill one or a limited number of those children?

> It would stop eg. the database or the web server, which is
> generally the main task of systems that run a database or
> a web server.

-- 
 Lubos Lunak
 openSUSE Boosters team, KDE developer
 l.lunak@...e.cz , l.lunak@....org
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