Date: Wed, 4 Nov 2009 09:25:34 +0900
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: David Rientjes <rientjes@google.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
       KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
       Andrea Arcangeli <aarcange@redhat.com>,
       Andrew Morton <akpm@linux-foundation.org>, minchan.kim@gmail.com,
       vedran.furac@gmail.com, Hugh Dickins <hugh.dickins@tiscali.co.uk>
Subject: Re: [RFC][-mm][PATCH 5/6] oom-killer: check last total_vm expansion
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On Tue, 3 Nov 2009 12:29:39 -0800 (PST)
David Rientjes <rientjes@google.com> wrote:

> On Mon, 2 Nov 2009, KAMEZAWA Hiroyuki wrote:
> 
> > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> > 
> > At considering oom-kill algorithm, we can't avoid to take runtime
> > into account. But this can adds too big bonus to slow-memory-leaker.
> > For adding penalty to slow-memory-leaker, we record jiffies of
> > the last mm->hiwater_vm expansion. That catches processes which leak
> > memory periodically.
> > 
> 
> No, it doesn't, it simply measures the last time the hiwater mark was 
> increased.  That could have increased by a single page in the last tick 
> with no increase in memory consumption over the past year and then its 
> unfairly biased against for quiet_time in the new oom kill heuristic 
> (patch 6).  Using this as part of the badness scoring is ill conceived 
> because it doesn't necessarily indicate a memory leaking task, just one 
> that has recently allocated memory.

Hmm. Maybe I can rewrite this as "periodic expansion have done or not" code.
Okay, this patch itself will be dropped.

If you find better algorithm, let me know.

Thanks,
-Kame

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