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In-Reply-To: Message from Jonathan Morton <chromi@cyberspace.org>    of
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Date: Mon, 26 Mar 2001 11:01:07 +0100
To: Horst von Brand <vonbrand@sleipnir.valparaiso.cl>
From: Jonathan Morton <chromi@cyberspace.org>
Subject: Re: [PATCH] Prevent OOM from killing init
Cc: Mike Galbraith <mikeg@wen-online.de>,
        linux-kernel <linux-kernel@vger.kernel.org>
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>> I'm currently investigating the old non-overcommit patch, which (apart from
>> needing manual applying to recent kernels) appears to be rather broken in a
>> trivial way.  It prevents allocation if total reserved memory is greater
>> than the total unallocated memory.  Let me say that again, a different way
>> - it prevents memory usage from exceeding 50%...
>
>Think fork(2).

fork() is allowed to return a failure value, and it already does so if
there isn't enough memory (at least with the limited tests I've come up
with).  Guess again.

I have, however, found a bug in the non-overcommit patch - it seems to be
capable of double-freeing (and then some) - starting 4 Java VMs and then
closing them causes VMReserved to go negative on my system.

--------------------------------------------------------------
from:     Jonathan "Chromatix" Morton
mail:     chromi@cyberspace.org  (not for attachments)
big-mail: chromatix@penguinpowered.com
uni-mail: j.d.morton@lancaster.ac.uk

The key to knowledge is not to rely on people to teach you it.

Get VNC Server for Macintosh from http://www.chromatix.uklinux.net/vnc/

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