Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759201AbZDQHpp (ORCPT ); Fri, 17 Apr 2009 03:45:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754634AbZDQHp1 (ORCPT ); Fri, 17 Apr 2009 03:45:27 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:47069 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757605AbZDQHp0 (ORCPT ); Fri, 17 Apr 2009 03:45:26 -0400 Date: Fri, 17 Apr 2009 16:43:51 +0900 From: KAMEZAWA Hiroyuki To: Gui Jianfeng Cc: Andrea Righi , Paul Menage , Balbir Singh , agk@sourceware.org, akpm@linux-foundation.org, axboe@kernel.dk, baramsori72@gmail.com, Carl Henrik Lunde , dave@linux.vnet.ibm.com, Divyesh Shah , eric.rannaud@gmail.com, fernando@oss.ntt.co.jp, Hirokazu Takahashi , Li Zefan , matt@bluehost.com, dradford@bluehost.com, ngupta@google.com, randy.dunlap@oracle.com, roberto@unbit.it, Ryo Tsuruta , Satoshi UCHIDA , subrata@linux.vnet.ibm.com, yoshikawa.takuya@oss.ntt.co.jp, containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/9] io-throttle documentation Message-Id: <20090417164351.ea85012d.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <49E8311D.5030901@cn.fujitsu.com> References: <1239740480-28125-1-git-send-email-righi.andrea@gmail.com> <1239740480-28125-2-git-send-email-righi.andrea@gmail.com> <20090417102417.88a0ef93.kamezawa.hiroyu@jp.fujitsu.com> <49E8311D.5030901@cn.fujitsu.com> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 2.5.0 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1820 Lines: 50 On Fri, 17 Apr 2009 15:34:53 +0800 Gui Jianfeng wrote: > KAMEZAWA Hiroyuki wrote: > > On Tue, 14 Apr 2009 22:21:12 +0200 > > Andrea Righi wrote: > > > >> +Example: > >> +* Create an association between an io-throttle group and a bio-cgroup group > >> + with "bio" and "blockio" subsystems mounted in different mount points: > >> + # mount -t cgroup -o bio bio-cgroup /mnt/bio-cgroup/ > >> + # cd /mnt/bio-cgroup/ > >> + # mkdir bio-grp > >> + # cat bio-grp/bio.id > >> + 1 > >> + # mount -t cgroup -o blockio blockio /mnt/io-throttle > >> + # cd /mnt/io-throttle > >> + # mkdir foo > >> + # echo 1 > foo/blockio.bio_id > > > > Why do we need multiple cgroups at once to track I/O ? > > Seems complicated to me. > > Hi Kamezawa-san, > > The original thought to implement this function is for sharing a bio-cgroup > with other subsystems, such as dm-ioband. If the bio-cgroup is already mounted, > and used by dm-ioband or others, we just need to create a association between > io-throttle and bio-cgroup by echo a bio-cgroup id, just like what dm-ioband does. > - Why we need multiple I/O controller ? - Why bio-cgroup cannot be a _pure_ infrastructe as page_cgroup ? - Why we need extra mount ? I have no answer but, IMHO, - only one I/O controller should be enabled at once. - bio cgroup should be tightly coupled with I/O controller and should work as infrastructure i.e. naming/tagging I/O should be automatically done by I/O controller. not by the user's hand. 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/