Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755898Ab0GVT3S (ORCPT ); Thu, 22 Jul 2010 15:29:18 -0400 Received: from smtp-out.google.com ([74.125.121.35]:28716 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752322Ab0GVT3Q convert rfc822-to-8bit (ORCPT ); Thu, 22 Jul 2010 15:29:16 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=mime-version:in-reply-to:references:from:date:message-id: subject:to:cc:content-type:content-transfer-encoding:x-system-of-record; b=hYAyu07Cug+SoJHZ+mF5d/ikuMuLvFJtmpqIhp6tlooJSuWTQkhzVr0/uDN3cSIFq hJNQ7NnFNcfhwe6R10oig== MIME-Version: 1.0 In-Reply-To: <20100712092004.3b27e13e.kamezawa.hiroyu@jp.fujitsu.com> References: <4C369009.80503@ds.jp.nec.com> <20100709134546.GC3672@redhat.com> <4C37BC1A.20102@ds.jp.nec.com> <20100710132417.GA2752@redhat.com> <20100712092004.3b27e13e.kamezawa.hiroyu@jp.fujitsu.com> From: Greg Thelen Date: Thu, 22 Jul 2010 12:28:50 -0700 Message-ID: Subject: Re: [RFC][PATCH 00/11] blkiocg async support To: KAMEZAWA Hiroyuki Cc: Vivek Goyal , Nauman Rafique , Munehiro Ikeda , linux-kernel@vger.kernel.org, Ryo Tsuruta , taka@valinux.co.jp, Andrea Righi , Gui Jianfeng , akpm@linux-foundation.org, balbir@linux.vnet.ibm.com Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2822 Lines: 66 On Sun, Jul 11, 2010 at 5:20 PM, KAMEZAWA Hiroyuki wrote: > On Sat, 10 Jul 2010 09:24:17 -0400 > Vivek Goyal wrote: > >> On Fri, Jul 09, 2010 at 05:55:23PM -0700, Nauman Rafique wrote: >> >> [..] >> > > Well, right. ?I agree. >> > > But I think we can work parallel. ?I will try to struggle on both. >> > >> > IMHO, we have a classic chicken and egg problem here. We should try to >> > merge pieces as they become available. If we get to agree on patches >> > that do async IO tracking for IO controller, we should go ahead with >> > them instead of trying to wait for per cgroup dirty ratios. >> > >> > In terms of getting numbers, we have been using patches that add per >> > cpuset dirty ratios on top of NUMA_EMU, and we get good >> > differentiation between buffered writes as well as buffered writes vs. >> > reads. >> > >> > It is really obvious that as long as flusher threads ,etc are not >> > cgroup aware, differentiation for buffered writes would not be perfect >> > in all cases, but this is a step in the right direction and we should >> > go for it. >> >> Working parallel on two separate pieces is fine. But pushing second piece >> in first does not make much sense to me because second piece does not work >> if first piece is not in. There is no way to test it. What's the point of >> pushing a code in kernel which only compiles but does not achieve intented >> purposes because some other pieces are missing. >> >> Per cgroup dirty ratio is a little hard problem and few attempts have >> already been made at it. IMHO, we need to first work on that piece and >> get it inside the kernel and then work on IO tracking patches. Lets >> fix the hard problem first that is necessary to make second set of patches >> work. >> > > I've just waited for dirty-ratio patches because I know someone is working on. > But, hmm, I'll consider to start work by myself. I have some patches that I have to address the dirty-ratios. I will post them. These dirty-ratio patches do not do anything intelligent wrt to per-cgroup writeback. When a cgroup dirty ratio is exceeded, a per-bdi writeback is triggered. > (Off-topic) > BTW, why io-cgroup's hierarchy level is limited to 2 ? > Because of that limitation, libvirt can't work well... > > Thanks, > -Kame > > -- > 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/ > -- 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/