From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754715AbYIWRvn (ORCPT ); Tue, 23 Sep 2008 13:51:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752747AbYIWRve (ORCPT ); Tue, 23 Sep 2008 13:51:34 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:54925 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752732AbYIWRvd (ORCPT ); Tue, 23 Sep 2008 13:51:33 -0400 Date: Wed, 24 Sep 2008 02:48:29 +0900 (JST) From: KOSAKI Motohiro To: "Michael Rubin" Subject: Re: [RFC] [PATCH -mm 0/2] memcg: per cgroup dirty_ratio Cc: kosaki.motohiro@jp.fujitsu.com, "Andrew Morton" , dradford@bluehost.com, m.innocenti@cineca.it, fernando@oss.ntt.co.jp, containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, chlunde@ping.uio.no, dave@linux.vnet.ibm.com, dpshah@google.com, agk@sourceware.org, matt@bluehost.com, menage@google.com, Andrea Righi , eric.rannaud@gmail.com, balbir@linux.vnet.ibm.com In-Reply-To: <532480950809221641y3471267esff82a14be8056586@mail.gmail.com> References: <20080912131816.e0cfac7a.akpm@linux-foundation.org> <532480950809221641y3471267esff82a14be8056586@mail.gmail.com> Message-Id: <20080924024437.DC21.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.42 [ja] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Currently the problem we are hitting is that we cannot specify pdflush > to have background limits less than 1% of memory. I am currently > finishing up a patch right now that adds a dirty_ratio_millis > interface. I hope to submit the patch to LKML by the end of the week. > > The idea is that we don't want to break backwards compatibility and we > also don't want to have two conflicting knobs in the sysctl or > /proc/sys/vm/ space. I thought adding a new knob for those who want to > specify finer grained functionality was a compromise. So the patch has > a vm_dirty_ratio and a vm_dirty_ratio_millis interface. The first to > specify 0-100% and the second to specify .0 to .999%. > > So to represent 0.125% of RAM we set > vm_dirty_ratio = 0 > vm_dirty_ratio_millis = 125 > > The same for the background_ratio. Why vm_dirty_ratio = 0.125 is wrong? it is hardly for parser maker, but it have nicer user experience. > > I would also prefer using a bytes interface but I am not sure how to > offer that without either removing the legacy interface of the ratios > or by offering a concurrent interface that might be confusing such as > when users are looking at the old one and not aware of a new one. > > Any feedback? Sure. We don't have any motivation of its interface change.