From mboxrd@z Thu Jan 1 00:00:00 1970 From: Balbir Singh Subject: Re: [PATCH 4/7] bio-cgroup: Split the cgroup memory subsystem into two parts Date: Tue, 19 Aug 2008 19:18:49 +0530 Message-ID: <48AACF41.5090905@linux.vnet.ibm.com> References: <20080818103938.8b4e8bfa.kamezawa.hiroyu@jp.fujitsu.com> <20080819.122811.59660409.ryov@valinux.co.jp> <48AA4594.1000908@linux.vnet.ibm.com> <20080819.214635.70071441.taka@valinux.co.jp> Reply-To: balbir@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20080819.214635.70071441.taka@valinux.co.jp> Sender: linux-kernel-owner@vger.kernel.org To: Hirokazu Takahashi Cc: ryov@valinux.co.jp, kamezawa.hiroyu@jp.fujitsu.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, xemul@openvz.org, fernando@oss.ntt.co.jp List-Id: dm-devel.ids Hirokazu Takahashi wrote: > Hi, > >>>> I'm now writing remove-lock-page-cgroup patches. it works well. >>>> please wait for a while... >>> I'm looking forward to those patches. >>> >>> By the way, I'm glad if memory-cgroup has a feature which can make a >>> page_cgroup move between cgroups with small overhead. It makes >>> bio-cgroup improve the accuracy of tracking down pages. >> Page movement can be a very expensive operation and is proportional to the size >> of the control group. I think movement should be an optional feature, if we ever >> add it. > > Yes, we should avoid moving pages as far as it is balanced fairly well > between groups. > > But I want to move pages between bio-cgoups in case it started charging > quite a few I/O requests to a wrong bio-cgroup. I think it will be okay > if pages moves between bio-cgroups, but they don't need to move between > memory cgroups. I know the latter is really heavy and the effect seems > to be so limited. I was under the impression that you wanted memory-cgroup to provide the page movement feature. That is not on the TODO list for us now. -- Balbir