From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754219Ab2LRT0p (ORCPT ); Tue, 18 Dec 2012 14:26:45 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45640 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750994Ab2LRT0n (ORCPT ); Tue, 18 Dec 2012 14:26:43 -0500 Date: Tue, 18 Dec 2012 14:26:33 -0500 From: Vivek Goyal To: Tejun Heo Cc: lizefan@huawei.com, axboe@kernel.dk, containers@lists.linux-foundation.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, ctalbott@google.com, rni@google.com Subject: Re: [PATCH 12/12] cfq-iosched: add hierarchical cfq_group statistics Message-ID: <20121218192633.GC25908@redhat.com> References: <1355524885-22719-1-git-send-email-tj@kernel.org> <1355524885-22719-13-git-send-email-tj@kernel.org> <20121218191117.GD24050@redhat.com> <20121218191425.GO1844@htj.dyndns.org> <20121218191854.GB25908@redhat.com> <20121218192155.GQ1844@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121218192155.GQ1844@htj.dyndns.org> 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 Tue, Dec 18, 2012 at 11:21:55AM -0800, Tejun Heo wrote: > On Tue, Dec 18, 2012 at 02:18:54PM -0500, Vivek Goyal wrote: > > > Yeah, hmmm, maybe we should add another set of counters to carry stats > > > from dead ones? Avoiding hierarchical accounting overhead in hot path > > > while remembering by-gones shouldn't be that hard. Will work on that. > > > > So are you planning to migrate the stats to parent when a cgroup is being > > deleted? That should make sure we don't do hierarhical update. > > Yeah, something like that. The current statistics being !hierarchical > means that we need to keep them separate from the actual stats, so > it'll end up with another set of stats. Kinda nasty but I don't see > any better way out. Separate stats for hierarchical migration make sense to me. Thanks Vivek