Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754300Ab3CVNCz (ORCPT ); Fri, 22 Mar 2013 09:02:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:25819 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753790Ab3CVNCy (ORCPT ); Fri, 22 Mar 2013 09:02:54 -0400 Message-ID: <514C5640.8000902@redhat.com> Date: Fri, 22 Mar 2013 09:01:52 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Will Huck CC: Johannes Weiner , Mel Gorman , Linux-MM , Jiri Slaby , Valdis Kletnieks , Zlatko Calusic , dormando , Satoru Moriya , Michal Hocko , LKML Subject: Re: [PATCH 01/10] mm: vmscan: Limit the number of pages kswapd reclaims at each priority References: <1363525456-10448-1-git-send-email-mgorman@suse.de> <1363525456-10448-2-git-send-email-mgorman@suse.de> <20130321155705.GA27848@cmpxchg.org> <514BA04D.2090002@gmail.com> <514BD56F.6050709@redhat.com> <514BD665.5020803@gmail.com> <514BE54C.4050106@gmail.com> In-Reply-To: <514BE54C.4050106@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1640 Lines: 45 On 03/22/2013 12:59 AM, Will Huck wrote: > Hi Rik, > On 03/22/2013 11:56 AM, Will Huck wrote: >> Hi Rik, >> On 03/22/2013 11:52 AM, Rik van Riel wrote: >>> On 03/21/2013 08:05 PM, Will Huck wrote: >>> >>>> One offline question, how to understand this in function balance_pgdat: >>>> /* >>>> * Do some background aging of the anon list, to give >>>> * pages a chance to be referenced before reclaiming. >>>> */ >>>> age_acitve_anon(zone, &sc); >>> >>> The anon lrus use a two-handed clock algorithm. New anonymous pages >>> start off on the active anon list. Older anonymous pages get moved >>> to the inactive anon list. >> >> The file lrus also use the two-handed clock algorithm, correct? > > After reinvestigate the codes, the answer is no. But why have this > difference? I think you are the expert for this question, expect your > explanation. :-) Anonymous memory has a smaller amount of memory (on the order of system memory), most of which is or has been in a working set at some point. File system cache tends to have two distinct sets. One part are the frequently accessed files, another part are the files that are accessed just once or twice. The file working set needs to be protected from streaming IO. We do this by having new file pages start out on the inactive file list, and only promoted to the active file list if they get accessed twice. -- All rights reversed -- 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/