From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id C09DF6B004F for ; Sun, 5 Jul 2009 13:15:29 -0400 (EDT) Received: from m2.gw.fujitsu.co.jp ([10.0.50.72]) by fgwmail6.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n65AcuZ3017297 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Sun, 5 Jul 2009 19:38:57 +0900 Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 952A445DE57 for ; Sun, 5 Jul 2009 19:38:56 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 66B1F45DE4F for ; Sun, 5 Jul 2009 19:38:56 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 44E84E18001 for ; Sun, 5 Jul 2009 19:38:56 +0900 (JST) Received: from m105.s.css.fujitsu.com (m105.s.css.fujitsu.com [10.249.87.105]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id E53D21DB803C for ; Sun, 5 Jul 2009 19:38:55 +0900 (JST) From: KOSAKI Motohiro Subject: Re: Found the commit that causes the OOMs In-Reply-To: <20090705095520.GA31587@localhost> References: <4A4AD07E.2040508@redhat.com> <20090705095520.GA31587@localhost> Message-Id: <20090705193551.090E.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Sun, 5 Jul 2009 19:38:54 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: kosaki.motohiro@jp.fujitsu.com, Rik van Riel , David Woodhouse , David Howells , Minchan Kim , Mel Gorman , Johannes Weiner , Andrew Morton , LKML , Christoph Lameter , "peterz@infradead.org" , "tytso@mit.edu" , "linux-mm@kvack.org" , "elladan@eskimo.com" , "npiggin@suse.de" , "Barnes, Jesse" List-ID: > >> OK. thanks. > >> I plan to submit this patch after small more tests. it is useful for OOM analysis. > > > > It is also useful for throttling page reclaim. > > > > If more than half of the inactive pages in a zone are > > isolated, we are probably beyond the point where adding > > additional reclaim processes will do more harm than good. > > Maybe we can try limiting the isolation phase of direct reclaims to > one per CPU? > > mutex_lock(per_cpu_lock); > isolate_pages(); > shrink_page_list(); > put_back_pages(); > mutex_unlock(per_cpu_lock); > > This way the isolated pages as well as major parts of direct reclaims > will be bounded by CPU numbers. The added overheads should be trivial > comparing to the reclaim costs. hm, this idea makes performance degression on few CPU machine, I think. e.g. if system have only one cpu and sysmtem makes lumpy reclaim, lumpy reclaim makes synchronous pageout and it makes very long waiting time. I suspect per-cpu decision is not useful in this area. thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org