From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id E9AAD6B0082 for ; Tue, 9 Jun 2009 04:08:34 -0400 (EDT) Received: from m1.gw.fujitsu.co.jp ([10.0.50.71]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n598bPVQ027784 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Tue, 9 Jun 2009 17:37:25 +0900 Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id C737045DD79 for ; Tue, 9 Jun 2009 17:37:24 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id A114745DD76 for ; Tue, 9 Jun 2009 17:37:24 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 8FBCCE08009 for ; Tue, 9 Jun 2009 17:37:24 +0900 (JST) Received: from m108.s.css.fujitsu.com (m108.s.css.fujitsu.com [10.249.87.108]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 1C4E3E08001 for ; Tue, 9 Jun 2009 17:37:24 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH mmotm] vmscan: handle may_swap more strictly (Re: [PATCH mmotm] vmscan: fix may_swap handling for memcg) In-Reply-To: <28c262360906090135x3382456by3518434a9939002b@mail.gmail.com> References: <20090609172035.DD7C.A69D9226@jp.fujitsu.com> <28c262360906090135x3382456by3518434a9939002b@mail.gmail.com> Message-Id: <20090609173605.DD82.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Tue, 9 Jun 2009 17:37:23 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Minchan Kim Cc: kosaki.motohiro@jp.fujitsu.com, Daisuke Nishimura , LKML , linux-mm , Andrew Morton , Johannes Weiner , Balbir Singh , KAMEZAWA Hiroyuki , Rik van Riel List-ID: > On Tue, Jun 9, 2009 at 5:24 PM, KOSAKI > Motohiro wrote: > >> On Tue, Jun 9, 2009 at 4:58 PM, KOSAKI > >> Motohiro wrote: > >> >> Hi, KOSAKI. > >> >> > >> >> As you know, this problem caused by if condition(priority) in shrink_zone. > >> >> Let me have a question. > >> >> > >> >> Why do we have to prevent scan value calculation when the priority is zero ? > >> >> As I know, before split-lru, we didn't do it. > >> >> > >> >> Is there any specific issue in case of the priority is zero ? > >> > > >> > Yes. > >> > > >> > example: > >> > > >> > get_scan_ratio() return anon:80%, file=20%. and the system have > >> > 10000 anon pages and 10000 file pages. > >> > > >> > shrink_zone() picked up 8000 anon pages and 2000 file pages. > >> > it mean 8000 file pages aren't scanned at all. > >> > > >> > Oops, it can makes OOM-killer although system have droppable file cache. > >> > > >> Hmm..Can that problem be happen in real system ? > >> The file ratio is big means that file lru list scanning is so big but > >> rotate is small. > >> It means file lru have few reclaimable page. > >> > >> Isn't it ? I am confusing. > >> Could you elaborate, please if you don't mind ? > > > > hm, ok, my example was wrong. > > I intention is, if there are droppable file-back pages (althout only 1 page), > > OOM-killer shouldn't occuer. > > > > many or few is unrelated. > > > > I am not sure that is effective. > Have you ever met this problem in real situation ? No. It's only stress workload issue. but VM subsystem sould work on stress workload, I think. > BTW, I have to dive into code. :) > Thanks for spending valuable time for commenting -- 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