From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx104.postini.com [74.125.245.104]) by kanga.kvack.org (Postfix) with SMTP id 774346B0033 for ; Tue, 23 Apr 2013 09:02:39 -0400 (EDT) Received: by mail-lb0-f180.google.com with SMTP id t11so621629lbi.11 for ; Tue, 23 Apr 2013 06:02:37 -0700 (PDT) Message-ID: <5176866A.2060400@openvz.org> Date: Tue, 23 Apr 2013 17:02:34 +0400 From: Konstantin Khlebnikov MIME-Version: 1.0 Subject: Re: [question] call mark_page_accessed() in minor fault References: <20130423122542.GA5638@gmail.com> In-Reply-To: <20130423122542.GA5638@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Zheng Liu Cc: linux-mm@kvack.org, muming.wq@taobao.com Zheng Liu wrote: > Hi all, > > Recently we meet a performance regression about mmaped page. When we upgrade > our product system from 2.6.18 kernel to a latest kernel, such as 2.6.32 kernel, > we will find that mmaped pages are reclaimed very quickly. We found that when > we hit a minor fault mark_page_accessed() is called in 2.6.18 kernel, but in > 2.6.32 kernel we don't call mark_page_accesed(). This means that mmaped pages > in 2.6.18 kernel are activated and moved into active list. While in 2.6.32 > kernel mmaped pages are still kept in inactive list. > > So my question is why we call mark_page_accessed() in 2.6.18 kernel, but don't > call it in 2.6.32 kernel. Has any reason here? Behavior was changed in commit v2.6.28-6130-gbf3f3bc "mm: don't mark_page_accessed in fault path" Please see also commits v3.2-4876-g34dbc67 "vmscan: promote shared file mapped pages" and v3.2-4877-gc909e99 "vmscan: activate executable pages after first usage". Probably they can solve some of your problems. > > Thanks in advance, > - Zheng > > -- > 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 -- 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