Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759491AbZFIIhb (ORCPT ); Tue, 9 Jun 2009 04:37:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758922AbZFIIhY (ORCPT ); Tue, 9 Jun 2009 04:37:24 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:58673 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758524AbZFIIhX (ORCPT ); Tue, 9 Jun 2009 04:37:23 -0400 From: KOSAKI Motohiro To: Minchan Kim Subject: Re: [PATCH mmotm] vmscan: handle may_swap more strictly (Re: [PATCH mmotm] vmscan: fix may_swap handling for memcg) Cc: kosaki.motohiro@jp.fujitsu.com, Daisuke Nishimura , LKML , linux-mm , Andrew Morton , Johannes Weiner , Balbir Singh , KAMEZAWA Hiroyuki , Rik van Riel 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 X-Mailer: Becky! ver. 2.50.07 [ja] Date: Tue, 9 Jun 2009 17:37:23 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1952 Lines: 61 > 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 from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/