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Date: Fri, 5 Dec 2003 23:56:15 +0100
From: Andrea Arcangeli <andrea@suse.de>
To: Kristian Peters <kristian.peters@korseby.net>,
       lkml <linux-kernel@vger.kernel.org>
Subject: Re: oom killer in 2.4.23
Message-ID: <20031205225615.GE2121@dualathlon.random>
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On Fri, Dec 05, 2003 at 02:38:25PM -0800, Mike Fedyk wrote:
> On Fri, Dec 05, 2003 at 02:05:20PM +0100, Kristian Peters wrote:
> 
> > Dec  5 13:34:41 adlib kernel: VM: killing process khexedit
> > Dec  5 13:37:27 adlib kernel: VM: killing process mozilla-bin
> > Dec  5 13:37:56 adlib kernel: VM: killing process mozilla-bin
> > Dec  5 13:40:32 adlib kernel: VM: killing process XFree86
> 
> This is with 2.4.23?
> 
> Why is the VM killing anything if the oom-killer is removed?

the 2.4.23 kernel will kill the task that triggered the oom condition,
it has to kill something of course, and the task that triggered the oom
during the page fault is the only one we can kill synchronously easily,
in turn guaranteeing that the machine won't deadlock in omm.

the oom killer normally is meant as the heuristc that chooses a special
task to kill, instead of the one that triggered the oom condition. But
choosing a different task and not the one that triggered the oom in the
page fault, isn't math safe w.r.t deadlocks.