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 B1D576B005C for ; Tue, 9 Jun 2009 03:51:00 -0400 (EDT) Received: by gxk28 with SMTP id 28so938553gxk.14 for ; Tue, 09 Jun 2009 01:19:20 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20090609164850.DD73.A69D9226@jp.fujitsu.com> References: <20090609161925.DD70.A69D9226@jp.fujitsu.com> <28c262360906090048x792fb3f9i6678298b693f6c5a@mail.gmail.com> <20090609164850.DD73.A69D9226@jp.fujitsu.com> Date: Tue, 9 Jun 2009 17:19:20 +0900 Message-ID: <28c262360906090119r6e881caq9b74028ba43567a7@mail.gmail.com> Subject: Re: [PATCH mmotm] vmscan: handle may_swap more strictly (Re: [PATCH mmotm] vmscan: fix may_swap handling for memcg) From: Minchan Kim Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Daisuke Nishimura , LKML , linux-mm , Andrew Morton , Johannes Weiner , Balbir Singh , KAMEZAWA Hiroyuki List-ID: 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 ? -- Kinds regards, Minchan Kim -- 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