From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757935Ab2EGUKP (ORCPT ); Mon, 7 May 2012 16:10:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57859 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757565Ab2EGUKN (ORCPT ); Mon, 7 May 2012 16:10:13 -0400 Message-ID: <4FA82C11.2030805@redhat.com> Date: Mon, 07 May 2012 16:09:53 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: KOSAKI Motohiro CC: Richard Davies , Satoru Moriya , Jerome Marchand , "jweiner@redhat.com" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "lwoodman@redhat.com" , "shaohua.li@intel.com" , "dle-develop@lists.sourceforge.net" , Seiji Aguchi , Minchan Kim Subject: Re: [RFC][PATCH] avoid swapping out with swappiness==0 References: <65795E11DBF1E645A09CEC7EAEE94B9CB951A45F@USINDEVS02.corp.hds.com> <20120424082019.GA18395@alpha.arachsys.com> <65795E11DBF1E645A09CEC7EAEE94B9C014649EC4D@USINDEVS02.corp.hds.com> <20120426142643.GA18863@alpha.arachsys.com> In-Reply-To: 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 04/26/2012 11:41 AM, KOSAKI Motohiro wrote: > On Thu, Apr 26, 2012 at 10:26 AM, Richard Davies > wrote: >> Satoru Moriya wrote: >>>> I have run into problems with heavy swapping with swappiness==0 and >>>> was pointed to this thread ( >>>> http://marc.info/?l=linux-mm&m=133522782307215 ) >>> >>> Did you test this patch with your workload? >> >> I haven't yet tested this patch. It takes a long time since these are >> production machines, and the bug itself takes several weeks of production >> use to really show up. >> >> Rik van Riel has pointed out a lot of VM tweaks that he put into 3.4: >> http://marc.info/?l=linux-mm&m=133536506926326 >> >> My intention is to reboot half of our machines into plain 3.4 once it is >> out, and half onto 3.4 + your patch. >> >> Then we can compare behaviour. >> >> Will your patch apply cleanly on 3.4? > > Note. This patch doesn't solve your issue. This patch mean, > when occuring very few swap io, it change to 0. But you said > you are seeing eager swap io. As Dave already pointed out, your > machine have buffer head issue. > > So, this thread is pointless. Running KVM guests directly off block devices results in a lot of buffer cache. I suspect that this patch will in fact fix Richard's issue. The patch is small, fairly simple and looks like it will fix people's problems. It also makes swappiness=0 behave the way most people seem to imagine it would work. If it works for a few people (test results), I believe we might as well merge it. Yes, for cgroups we may need additional logic, but we can sort that out as we go along. -- All rights reversed From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx102.postini.com [74.125.245.102]) by kanga.kvack.org (Postfix) with SMTP id BDF696B004D for ; Mon, 7 May 2012 16:10:05 -0400 (EDT) Message-ID: <4FA82C11.2030805@redhat.com> Date: Mon, 07 May 2012 16:09:53 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [RFC][PATCH] avoid swapping out with swappiness==0 References: <65795E11DBF1E645A09CEC7EAEE94B9CB951A45F@USINDEVS02.corp.hds.com> <20120424082019.GA18395@alpha.arachsys.com> <65795E11DBF1E645A09CEC7EAEE94B9C014649EC4D@USINDEVS02.corp.hds.com> <20120426142643.GA18863@alpha.arachsys.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: Richard Davies , Satoru Moriya , Jerome Marchand , "jweiner@redhat.com" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "lwoodman@redhat.com" , "shaohua.li@intel.com" , "dle-develop@lists.sourceforge.net" , Seiji Aguchi , Minchan Kim On 04/26/2012 11:41 AM, KOSAKI Motohiro wrote: > On Thu, Apr 26, 2012 at 10:26 AM, Richard Davies > wrote: >> Satoru Moriya wrote: >>>> I have run into problems with heavy swapping with swappiness==0 and >>>> was pointed to this thread ( >>>> http://marc.info/?l=linux-mm&m=133522782307215 ) >>> >>> Did you test this patch with your workload? >> >> I haven't yet tested this patch. It takes a long time since these are >> production machines, and the bug itself takes several weeks of production >> use to really show up. >> >> Rik van Riel has pointed out a lot of VM tweaks that he put into 3.4: >> http://marc.info/?l=linux-mm&m=133536506926326 >> >> My intention is to reboot half of our machines into plain 3.4 once it is >> out, and half onto 3.4 + your patch. >> >> Then we can compare behaviour. >> >> Will your patch apply cleanly on 3.4? > > Note. This patch doesn't solve your issue. This patch mean, > when occuring very few swap io, it change to 0. But you said > you are seeing eager swap io. As Dave already pointed out, your > machine have buffer head issue. > > So, this thread is pointless. Running KVM guests directly off block devices results in a lot of buffer cache. I suspect that this patch will in fact fix Richard's issue. The patch is small, fairly simple and looks like it will fix people's problems. It also makes swappiness=0 behave the way most people seem to imagine it would work. If it works for a few people (test results), I believe we might as well merge it. Yes, for cgroups we may need additional logic, but we can sort that out as we go along. -- All rights reversed -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org