From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932329Ab2CENuF (ORCPT ); Mon, 5 Mar 2012 08:50:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44421 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932246Ab2CENuD (ORCPT ); Mon, 5 Mar 2012 08:50:03 -0500 Message-ID: <4F54C460.2030405@redhat.com> Date: Mon, 05 Mar 2012 08:49:20 -0500 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.1) Gecko/20120216 Thunderbird/10.0.1 MIME-Version: 1.0 To: Satoru Moriya CC: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "lwoodman@redhat.com" , "jweiner@redhat.com" , "shaohua.li@intel.com" , KOSAKI Motohiro , "dle-develop@lists.sourceforge.net" , Seiji Aguchi Subject: Re: [RFC][PATCH] avoid swapping out with swappiness==0 References: <65795E11DBF1E645A09CEC7EAEE94B9CB9455FE2@USINDEVS02.corp.hds.com> In-Reply-To: <65795E11DBF1E645A09CEC7EAEE94B9CB9455FE2@USINDEVS02.corp.hds.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 03/02/2012 12:36 PM, Satoru Moriya wrote: > Sometimes we'd like to avoid swapping out anonymous memory > in particular, avoid swapping out pages of important process or > process groups while there is a reasonable amount of pagecache > on RAM so that we can satisfy our customers' requirements. > > OTOH, we can control how aggressive the kernel will swap memory pages > with /proc/sys/vm/swappiness for global and > /sys/fs/cgroup/memory/memory.swappiness for each memcg. > > But with current reclaim implementation, the kernel may swap out > even if we set swappiness==0 and there is pagecache on RAM. > > This patch changes the behavior with swappiness==0. If we set > swappiness==0, the kernel does not swap out completely > (for global reclaim until the amount of free pages and filebacked > pages in a zone has been reduced to something very very small > (nr_free + nr_filebacked< high watermark)). > > Any comments are welcome. My mind is now rested by doing a nice 10 mile hike :) > Signed-off-by: Satoru Moriya Reviewed-by: Rik van Riel -- All rights reversed