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Date: Sat, 16 May 2009 02:01:22 +0530
From: Balbir Singh <balbir@linux.vnet.ibm.com>
To: Christoph Lameter <cl@linux-foundation.org>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>, Pavel Machek <pavel@ucw.cz>,
       David Rientjes <rientjes@google.com>,
       Andrew Morton <akpm@linux-foundation.org>,
       Greg Kroah-Hartman <gregkh@suse.de>, Nick Piggin <npiggin@suse.de>,
       Mel Gorman <mel@csn.ul.ie>, Peter Ziljstra <a.p.ziljstra@chello.nl>,
       San Mehat <san@android.com>, Arve Hj?nnev?g <arve@android.com>,
       linux-kernel@vger.kernel.org
Subject: Re: Misleading OOM messages
Message-ID: <20090515203122.GM4451@balbir.in.ibm.com>
Reply-To: balbir@linux.vnet.ibm.com
References: <20090514092909.GG1365@ucw.cz> <alpine.DEB.1.10.0905141546040.1381@qirst.com> <1242333519.15391.210.camel@nimitz> <alpine.DEB.2.00.0905141346030.28074@chino.kir.corp.google.com> <1242335120.15391.242.camel@nimitz> <alpine.DEB.1.10.0905141729180.30187@qirst.com> <20090514213403.GB14741@elf.ucw.cz> <alpine.DEB.1.10.0905151346550.26559@qirst.com> <1242411307.28257.25.camel@nimitz> <alpine.DEB.1.10.0905151526170.13433@qirst.com>
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* Christoph Lameter <cl@linux-foundation.org> [2009-05-15 15:26:43]:

> On Fri, 15 May 2009, Dave Hansen wrote:
> 
> > On Fri, 2009-05-15 at 13:57 -0400, Christoph Lameter wrote:
> > > > If you misconfigured cgroups, you give more memory to them.
> > >
> > > If you do not have enough memory in a cgroup then your application should
> > > slow down (because of page evictions) but the system should not OOM.
> > > Are cgroups broken or why are you getting OOMs when using them?
> >
> > See mm/oom_kill.c::mem_cgroup_out_of_memory().  A group itself can have
> > an OOM done on it.  It's not a system-wide oom.  We just need to ensure
> > that we continue to differentiate the cgroup-specific oom message from
> > the general one.  Maybe also include some more cgroup info in the debug
> > outbut.
> 
> But that is a resource control isssue. Should also not say out of memory
> but state that the cgroup memory limit was reached.
>

But we are out of memory for the cgroup under consideration. 

-- 
	Balbir