Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758911AbYHELTX (ORCPT ); Tue, 5 Aug 2008 07:19:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756094AbYHELTA (ORCPT ); Tue, 5 Aug 2008 07:19:00 -0400 Received: from as3.cineca.com ([130.186.84.211]:42720 "EHLO as3.cineca.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753469AbYHELTA (ORCPT ); Tue, 5 Aug 2008 07:19:00 -0400 Message-ID: <48981E03.5020406@gmail.com> From: Andrea Righi Reply-To: righi.andrea@gmail.com User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.12) Gecko/20070604 Thunderbird/1.5.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 To: Hirokazu Takahashi Cc: dave@linux.vnet.ibm.com, xen-devel@lists.xensource.com, containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, dm-devel@redhat.com, agk@sourceware.org Subject: Re: Too many I/O controller patches References: <489748E6.5080106@gmail.com> <1217876521.20260.123.camel@nimitz> <48976A2A.9060600@gmail.com> <20080805.151642.31467169.taka@valinux.co.jp> In-Reply-To: <20080805.151642.31467169.taka@valinux.co.jp> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Date: Tue, 5 Aug 2008 11:31:47 +0200 (MEST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2054 Lines: 41 Hirokazu Takahashi wrote: > Hi, Andrea, > > I'm working with Ryo on dm-ioband and other stuff. > >>> On Mon, 2008-08-04 at 20:22 +0200, Andrea Righi wrote: >>>> But I'm not yet convinced that limiting the IO writes at the device >>>> mapper layer is the best solution. IMHO it would be better to throttle >>>> applications' writes when they're dirtying pages in the page cache (the >>>> io-throttle way), because when the IO requests arrive to the device >>>> mapper it's too late (we would only have a lot of dirty pages that are >>>> waiting to be flushed to the limited block devices, and maybe this could >>>> lead to OOM conditions). IOW dm-ioband is doing this at the wrong level >>>> (at least for my requirements). Ryo, correct me if I'm wrong or if I've >>>> not understood the dm-ioband approach. >>> The avoid-lots-of-page-dirtying problem sounds like a hard one. But, if >>> you look at this in combination with the memory controller, they would >>> make a great team. >>> >>> The memory controller keeps you from dirtying more than your limit of >>> pages (and pinning too much memory) even if the dm layer is doing the >>> throttling and itself can't throttle the memory usage. >> mmh... but in this way we would just move the OOM inside the cgroup, >> that is a nice improvement, but the main problem is not resolved... > > The concept of dm-ioband includes it should be used with cgroup memory > controller as well as the bio cgroup. The memory controller is supposed > to control memory allocation and dirty-page ratio inside each cgroup. > > Some guys of cgroup memory controller team just started to implement > the latter mechanism. They try to make each cgroup have a threshold > to limit the number of dirty pages in the group. Interesting, they also post a patch or RFC? -Andrea -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/