Date: Tue, 16 Feb 2010 17:20:35 +1100
From: Nick Piggin <npiggin@suse.de>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, Rik van Riel <riel@redhat.com>,
       KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
       Andrea Arcangeli <aarcange@redhat.com>,
       Balbir Singh <balbir@linux.vnet.ibm.com>, Lubos Lunak <l.lunak@suse.cz>,
       KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
       linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [patch -mm 4/9 v2] oom: remove compulsory panic_on_oom mode
Message-ID: <20100216062035.GA5723@laptop>
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On Mon, Feb 15, 2010 at 02:20:09PM -0800, David Rientjes wrote:
> If /proc/sys/vm/panic_on_oom is set to 2, the kernel will panic
> regardless of whether the memory allocation is constrained by either a
> mempolicy or cpuset.
> 
> Since mempolicy-constrained out of memory conditions now iterate through
> the tasklist and select a task to kill, it is possible to panic the
> machine if all tasks sharing the same mempolicy nodes (including those
> with default policy, they may allocate anywhere) or cpuset mems have
> /proc/pid/oom_adj values of OOM_DISABLE.  This is functionally equivalent
> to the compulsory panic_on_oom setting of 2, so the mode is removed.
> 
> Signed-off-by: David Rientjes <rientjes@google.com>

What is the point of removing it, though? If it doesn't significantly
help some future patch, just leave it in. It's not worth breaking the
user/kernel interface just to remove 3 trivial lines of code.

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