From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423066AbXCBNH1 (ORCPT ); Fri, 2 Mar 2007 08:07:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1423065AbXCBNH1 (ORCPT ); Fri, 2 Mar 2007 08:07:27 -0500 Received: from main.gmane.org ([80.91.229.2]:40123 "EHLO ciao.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423064AbXCBNH0 (ORCPT ); Fri, 2 Mar 2007 08:07:26 -0500 X-Injected-Via-Gmane: http://gmane.org/ To: linux-kernel@vger.kernel.org From: Leroy van Logchem Subject: Re: [RFC][PATCH 0/3] VM throttling: avoid blocking =?utf-8?b?b2NjYXNpb25hbAl3cml0ZXJz?= Date: Fri, 2 Mar 2007 13:06:30 +0000 (UTC) Message-ID: References: <45DED819.9040404@hitachi.com> <17888.14958.85897.289141@gargle.gargle.HOWL> <45E380DA.6090509@hitachi.com> <1172826980.9640.13.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@sea.gmane.org X-Gmane-NNTP-Posting-Host: main.gmane.org User-Agent: Loom/3.14 (http://gmane.org/) X-Loom-IP: 145.9.150.34 (Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.2) Gecko/20060601 Firefox/2.0.0.2 (Ubuntu-edgy)) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > I'm sorry to piggy-back this thread. > > Could it be what I'm experiencing in the following bugzilla report: > http://bugzilla.kernel.org/show_bug.cgi?id=7372 > > As I explained in the report, I see this issue only since 2.6.18. > So if your concern is related to mine, what could have changed between > 2.6.17 and 2.6.18 related to this? I don't think it's 2.6.x related, it's been under the sheets from start. Related to your problem in the 7372 bug: Pages are kept in memory for re-use, which is fast and fine except for: 1) data without re-use value or even single use 2) applications _do not_ advise the kernel how to cache pages related to there self generated i/o. POSIX does provide mechanisms to properly do so. But the kernel should help these poor apps. To minimize your MySQL backup cp(1) problem, try this workaround: cat ./cp_direct.sh #!/bin/sh dd if=$1 of=$2 bs=1M iflag=direct oflag=direct Combine this with [/etc/sysctl.conf]: vm.vfs_cache_pressure = 1 vm.dirty_ratio = 2 vm.dirty_background_ratio = 1 This should reduce both the stress on the vm and response latency during interactive work. -- Leroy