Date: Wed, 28 Oct 2009 09:32:26 +0900
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>,
       Minchan Kim <minchan.kim@gmail.com>,
       KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
       vedran.furac@gmail.com, linux-mm@kvack.org,
       linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
       rientjes@google.com
Subject: Re: [RFC][PATCH] oom_kill: avoid depends on total_vm and use real
 RSS/swap value for oom_score (Re: Memory overcommit
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On Tue, 27 Oct 2009 19:47:43 +0100
Andrea Arcangeli <aarcange@redhat.com> wrote: 
> > should be included along with rss isn't quite clear to me: I'm not
> > saying you're wrong, not at all, just that it's not quite obvious.
> 
> Agreed it's not obvious. Intuitively I think only including RSS and no
> swap is best, but clearly I can't be entirely against including swap
> too as there may be scenarios where including swap provides for a
> better choice.
> 
> My argument for not including swap is that we kill tasks to free RAM
> (we don't really care to free swap, system needs RAM at oom time).
> Freeing swap won't immediately help because no RAM is freed when swap
> is released (sure other tasks that sits huge in RAM can be moved to
> swap after swap isn't full but if we immediately killed those tasks
> that were huge in RAM in the first place we'd be better off).
> 
Okay.

As first step, I'll divide this into 
   - replace total_vm with anon_rss/file_rss patch
   - swap accounting
   - a patch for consider whether swap amount should be included or not.

Then, necessary part will go early. And backport will be easy.

Thanks,
-Kame


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