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Date: Thu, 18 Oct 2007 22:38:21 +0200
From: Rene Herman <rene.herman@keyaccess.nl>
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To: Marcelo Tosatti <marcelo@kvack.org>
CC: linux-kernel@vger.kernel.org, riel@redhat.com, drepper@redhat.com
Subject: Re: OOM notifications
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On 10/18/2007 10:25 PM, Marcelo Tosatti wrote:

> AIX contains the SIGDANGER signal to notify applications to free up some
> unused cached memory:
> 
> http://www.ussg.iu.edu/hypermail/linux/kernel/0007.0/0901.html
> 
> There have been a few discussions on implementing such an idea on Linux,
> but nothing concrete has been achieved.
> 
> On the kernel side Rik suggested two notification points: "about to
> swap" (for desktop scenarios) and "about to OOM" (for embedded-like
> scenarios).
> 
> With that assumption in mind it would be necessary to either have two
> special devices for notification, or somehow indicate both events
> through the same file descriptor.
> 
> Comments are more than welcome.

Given the desktop/embedded distinction you made, do you need both scenarios 
active at the same time? If not, it seems something like a

	echo -n <level> >/proc/sys/vm/danger

could do with just one sigdanger notification point? (with <level> suitably 
defined as or in terms of the used threshold value).

Rene.
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