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Date: Tue, 27 Mar 2001 23:13:47 +0200
From: Andreas Rogge <lu01@rogge.yi.org>
To: Andreas Dilger <adilger@turbolinux.com>,
        Martin Dalecki <dalecki@evision-ventures.com>
cc: Ingo Oeser <ingo.oeser@informatik.tu-chemnitz.de>,
        Jonathan Morton <chromi@cyberspace.org>,
        Rogier Wolff <R.E.Wolff@bitwizard.nl>, linux-kernel@vger.kernel.org
Subject: Re: OOM killer???
Message-ID: <237970000.985727627@hades>
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--On Tuesday, March 27, 2001 12:55:50 -0700 Andreas Dilger 
<adilger@turbolinux.com> wrote:

> Every time this subject comes up, I point to AIX and SIGDANGER - a signal
> sent to processes when the system gets OOM.  If the process has registered
> a SIGDANGER handler, it has a chance to free cache and such (or do a clean
> shutdown), otherwise the default signal handler will kill the process.

Having a SIGDANGER would be a fine thing, but this will need patching in all
current daemons and there has to be a possibility to configure the behaviour
of the process when recieving a SIGDANGER. i.e. it is a good idea to kill
apache on a workstation, but a very bad idea to kill apache on a webserver.
Generally I'd like to see such an implementation, but wouldn't it be better
to have a pre-seclction of the processes getting SIGDANGER?

For example: if OOM occours, send SIGDANGER to all non-root-processes with a
nice-level of n or higher (where n should be discussed).

This would make it easy to "configure" SIGDANGER-unaware Applications - in 
the meantime, until all applications are SIGDANGER-aware -  to deal with
OOM-situations. You just do an "nice -n -1 httpd" and one's httpd won't
get killed when OOM occours.

IMO this would dramatically improve the OOM-Problems right now.

--
Andreas Rogge <lu01@rogge.yi.org>
Available on IRCnet:#linux.de as Dyson
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