linux-kernel - Re: [why oom_adj does not work] Re: Linux killed Kenny, bastard!

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Message-ID: <20090115084328.GA29586@ioremap.net>
Date:	Thu, 15 Jan 2009 11:43:28 +0300
From:	Evgeniy Polyakov <zbr@...emap.net>
To:	David Rientjes <rientjes@...gle.com>
Cc:	Bodo Eggert <7eggert@....de>, Alan Cox <alan@...rguk.ukuu.org.uk>,
	Dave Jones <davej@...hat.com>, linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [why oom_adj does not work] Re: Linux killed Kenny, bastard!

On Wed, Jan 14, 2009 at 04:54:09PM -0800, David Rientjes (rientjes@...gle.com) wrote:
> > This does not work if processes are short-living and are spawned by the
> > parent on demand. If processes have different priority in regards to oom
> > condition, this problem can not be solved with existing interfaces
> > without changing the application. So effectively there is no solution.
> > 
> 
> Wrong, you can change how the application is forked.  Either immediately 
> adjust /proc/$!/oom_adj or use the adjustment inheritance property and 
> change /proc/$$/oom_adj to the desired value prior to forking.  Thanks.

You and Alan so like bash... Applications are not always forked from shell.

I already pointed multiple times where parent om_adj changes lead, and
that this does not work in a real world for some common cases. Existing
scheme only works if some daemon (or application itself) explicitely
changes oom_adj, but no dameon exists to monitor /proc and applications
do not change their own and child's oom_adj because it is way too
linuxish to add such hacks to deal with system's oom-killer, which can
not be properly configured otherwise.

-- 
	Evgeniy Polyakov
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