Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759354AbZFIIfT (ORCPT ); Tue, 9 Jun 2009 04:35:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757795AbZFIIfI (ORCPT ); Tue, 9 Jun 2009 04:35:08 -0400 Received: from yw-out-2324.google.com ([74.125.46.29]:18698 "EHLO yw-out-2324.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757610AbZFIIfH (ORCPT ); Tue, 9 Jun 2009 04:35:07 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=bP6/4Q2pa6Qns8zY94lMcAnzJk0kDdQwmMyiwbu4x7YOOQy4ZVqFqEeh/YdKfAdOCt gTnas8cqgNV8JKpp2meWyBKl9zPf1GDwoD4RnVYKWP3H8D7/UBGSP2EmutXTv7feNIKf yYGwHdjjYCyJ5LiNWDp8C3duQClahF1g15uKw= MIME-Version: 1.0 In-Reply-To: <20090609172035.DD7C.A69D9226@jp.fujitsu.com> References: <20090609164850.DD73.A69D9226@jp.fujitsu.com> <28c262360906090119r6e881caq9b74028ba43567a7@mail.gmail.com> <20090609172035.DD7C.A69D9226@jp.fujitsu.com> Date: Tue, 9 Jun 2009 17:35:09 +0900 Message-ID: <28c262360906090135x3382456by3518434a9939002b@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 To: KOSAKI Motohiro Cc: Daisuke Nishimura , LKML , linux-mm , Andrew Morton , Johannes Weiner , Balbir Singh , KAMEZAWA Hiroyuki , Rik van Riel Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1793 Lines: 55 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 ? BTW, I have to dive into code. :) Thanks for spending valuable time for commenting -- Kinds regards, Minchan Kim -- 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/