From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754110Ab1BPSGj (ORCPT ); Wed, 16 Feb 2011 13:06:39 -0500 Received: from mx1.redhat.com ([209.132.183.28]:28054 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753975Ab1BPSGh (ORCPT ); Wed, 16 Feb 2011 13:06:37 -0500 Date: Wed, 16 Feb 2011 13:06:28 -0500 From: Vivek Goyal To: Divyesh Shah Cc: Gui Jianfeng , Jens Axboe , Shaohua Li , lkml , Chad Talbott Subject: Re: [PATCH 5/6 v4] cfq-iosched: CFQ group hierarchical scheduling and use_hierarchy interface Message-ID: <20110216180628.GF14653@redhat.com> References: <4D51ED26.8050809@cn.fujitsu.com> <4D539821.1090703@cn.fujitsu.com> <20110210205722.GB2600@redhat.com> <4D55EEBB.8060304@cn.fujitsu.com> <20110214180428.GF13097@redhat.com> <4D59E728.3030209@cn.fujitsu.com> <20110215142752.GC27296@redhat.com> <4D5B2C07.9050909@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 16, 2011 at 09:28:07AM -0800, Divyesh Shah wrote: > On Wed, Feb 16, 2011 at 9:22 AM, Divyesh Shah wrote: > > On Tue, Feb 15, 2011 at 5:44 PM, Gui Jianfeng > > wrote: > >> Hmm, it seems memcg aggregating stats in parent group. > >> But do we really need to do that in kernel? I think it's easier to do it in > >> userland, and it makes kernel much simpler. > >> > > > > I would prefer having stats aggregated up the hierarchy. One trick we > > used at Google earlier was to do lazy updates for most stats. So we > > Note that this was on ancient version of the blkio controller :). As > Vivek mentioned, > it may be ok to add the hierarchical accounting later. One improvement we can probably do is make accounting per cpu and make it lockless. Thanks Vivek