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Date: Tue, 2 Mar 2010 16:53:00 -0800 (PST)
From: David Rientjes <rientjes@google.com>
Subject: Re: [patch -mm v2 04/10] oom: remove special handling for pagefault
 ooms
In-Reply-To: <20100303094438.1e9b09fb.kamezawa.hiroyu@jp.fujitsu.com>
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To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>, Andrew Morton <akpm@linux-foundation.org>, Rik van Riel <riel@redhat.com>, Nick Piggin <npiggin@suse.de>, KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>, linux-mm@kvack.org
List-ID: <linux-mm.kvack.org>

On Wed, 3 Mar 2010, KAMEZAWA Hiroyuki wrote:

> memory_cgroup_out_of_memory() kills a task. and return VM_FAULT_OOM then,
> page_fault_out_of_memory() kills another task.
> and cause panic if panic_on_oom=1.
> 

If mem_cgroup_out_of_memory() has returned, then it has already killed a 
task that will have TIF_MEMDIE set and therefore make the VM_FAULT_OOM oom 
a no-op.  If the oom killed task subsequently returns VM_FAULT_OOM, we 
better panic because we've fully depleted memory reserves and no future 
memory freeing is guaranteed.

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