From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757615Ab2AROSG (ORCPT ); Wed, 18 Jan 2012 09:18:06 -0500 Received: from mx1.redhat.com ([209.132.183.28]:10837 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757466Ab2AROSE (ORCPT ); Wed, 18 Jan 2012 09:18:04 -0500 Message-ID: <4F16D46D.5080000@redhat.com> Date: Wed, 18 Jan 2012 09:17:17 -0500 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:9.0) Gecko/20111222 Thunderbird/9.0 MIME-Version: 1.0 To: KAMEZAWA Hiroyuki CC: Minchan Kim , linux-mm , LKML , leonid.moiseichuk@nokia.com, penberg@kernel.org, mel@csn.ul.ie, rientjes@google.com, KOSAKI Motohiro , Johannes Weiner , Marcelo Tosatti , Andrew Morton , Ronen Hod Subject: Re: [RFC 2/3] vmscan hook References: <1326788038-29141-1-git-send-email-minchan@kernel.org> <1326788038-29141-3-git-send-email-minchan@kernel.org> <20120117173932.1c058ba4.kamezawa.hiroyu@jp.fujitsu.com> <20120117091356.GA29736@barrios-desktop.redhat.com> <20120117190512.047d3a03.kamezawa.hiroyu@jp.fujitsu.com> <20120117230801.GA903@barrios-desktop.redhat.com> <20120118091824.0bde46f7.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20120118091824.0bde46f7.kamezawa.hiroyu@jp.fujitsu.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 On 01/17/2012 07:18 PM, KAMEZAWA Hiroyuki wrote: > On Wed, 18 Jan 2012 08:08:01 +0900 > Minchan Kim wrote: > >>>>> 2. can't we measure page-in/page-out distance by recording something ? >>>> >>>> I can't understand your point. What's relation does it with swapout prevent? >>>> >>> >>> If distance between pageout -> pagein is short, it means thrashing. >>> For example, recoding the timestamp when the page(mapping, index) was >>> paged-out, and check it at page-in. >> >> Our goal is prevent swapout. When we found thrashing, it's too late. > > If you want to prevent swap-out, don't swapon any. That's all. > Then, you can check the number of FILE_CACHE and have threshold. I think you are getting hung up on a word here. As I understand it, the goal is to push out the point where we start doing heavier swap IO, allowing us to overcommit memory more heavily before things start really slowing down. -- All rights reversed