From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758733Ab2DZSUQ (ORCPT ); Thu, 26 Apr 2012 14:20:16 -0400 Received: from smtp106.prem.mail.ac4.yahoo.com ([76.13.13.45]:42414 "HELO smtp106.prem.mail.ac4.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1758672Ab2DZSUP (ORCPT ); Thu, 26 Apr 2012 14:20:15 -0400 X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: cpDcYX4VM1lZED5hfns_0IK1zU3CPr7fYlEkqAcjmR1Gyea qYF9MO9q.X8.e1apY7IfUrSGMMyZoEU9edlaNavBI2JnmwtTjBqr6D6M6Pg1 nQKjKRhMgkFGVYHGeiShlr12QQxc1ouTRamLejgngh1U_Vwd9OEJ6A5dfxM6 61Z2hslrZAPeJmdBFsabOMjuoqv0S2EiTt6nRrR3jPf8pdn3J_CBEKdDpBgO UYpbHjCpXN.ORiuh7ALP_OKhH5SWAP6b3QBGzMLa2zZQZm2VC1y1EkUi5WDN SNHv375kjKp49PFZpPKpTwP.fMvKL_6oWGLxGeqBmwJPC.oMToF7.E4shji7 wzmQ7URSZTZUgs4cb.jeRs7FltVssaDYjIJ.ym6iNWIoyGhpDhjtRsEItEdT a X-Yahoo-SMTP: _Dag8S.swBC1p4FJKLCXbs8NQzyse1SYSgnAbY0- Date: Thu, 26 Apr 2012 13:20:09 -0500 (CDT) From: Christoph Lameter X-X-Sender: cl@router.home To: KOSAKI Motohiro cc: Richard Davies , Satoru Moriya , Jerome Marchand , KOSAKI Motohiro , "jweiner@redhat.com" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "riel@redhat.com" , "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 In-Reply-To: <4F996BA6.9010900@gmail.com> Message-ID: References: <20120424082019.GA18395@alpha.arachsys.com> <4F996BA6.9010900@gmail.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 26 Apr 2012, KOSAKI Motohiro wrote: > (4/26/12 10:50 AM), Christoph Lameter wrote: > > On Tue, 24 Apr 2012, Richard Davies wrote: > > > > > I strongly believe that Linux should have a way to turn off swapping > > > unless > > > absolutely necessary. This means that users like us can run with swap > > > present for emergency use, rather than having to disable it because of the > > > side effects. > > > > Agree. And this ooperation mode should be the default behavior given that > > swapping is a very slow and tedious process these days. > > Even though current patch is not optimal, I don't disagree this opinion. Can > you please explain your use case? Why don't you use swapoff? Because I do not want to have systems go OOM. In an emergency lets use swap (and maybe generate some sort of alert if that happens). > Off topic: I hope linux is going to aim good swap clustered io in future. > Especially > when using THP, 4k size io is not really good. Swap to regular disks is going to be an ever greater problem since the access speed of rotational media has not changed much whereas the processing performance of the cpu has increased significantly. There is an ever increasing gap in speed. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx164.postini.com [74.125.245.164]) by kanga.kvack.org (Postfix) with SMTP id 80ABE6B0044 for ; Thu, 26 Apr 2012 14:20:14 -0400 (EDT) Date: Thu, 26 Apr 2012 13:20:09 -0500 (CDT) From: Christoph Lameter Subject: Re: [RFC][PATCH] avoid swapping out with swappiness==0 In-Reply-To: <4F996BA6.9010900@gmail.com> Message-ID: References: <20120424082019.GA18395@alpha.arachsys.com> <4F996BA6.9010900@gmail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: Richard Davies , Satoru Moriya , Jerome Marchand , KOSAKI Motohiro , "jweiner@redhat.com" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "riel@redhat.com" , "lwoodman@redhat.com" , "shaohua.li@intel.com" , "dle-develop@lists.sourceforge.net" , Seiji Aguchi , Minchan Kim On Thu, 26 Apr 2012, KOSAKI Motohiro wrote: > (4/26/12 10:50 AM), Christoph Lameter wrote: > > On Tue, 24 Apr 2012, Richard Davies wrote: > > > > > I strongly believe that Linux should have a way to turn off swapping > > > unless > > > absolutely necessary. This means that users like us can run with swap > > > present for emergency use, rather than having to disable it because of the > > > side effects. > > > > Agree. And this ooperation mode should be the default behavior given that > > swapping is a very slow and tedious process these days. > > Even though current patch is not optimal, I don't disagree this opinion. Can > you please explain your use case? Why don't you use swapoff? Because I do not want to have systems go OOM. In an emergency lets use swap (and maybe generate some sort of alert if that happens). > Off topic: I hope linux is going to aim good swap clustered io in future. > Especially > when using THP, 4k size io is not really good. Swap to regular disks is going to be an ever greater problem since the access speed of rotational media has not changed much whereas the processing performance of the cpu has increased significantly. There is an ever increasing gap in speed. -- 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