From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753209Ab2LQVPZ (ORCPT ); Mon, 17 Dec 2012 16:15:25 -0500 Received: from mail-pb0-f46.google.com ([209.85.160.46]:45174 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752092Ab2LQVPX (ORCPT ); Mon, 17 Dec 2012 16:15:23 -0500 Date: Mon, 17 Dec 2012 13:15:17 -0800 From: Tejun Heo To: Vivek Goyal 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 06/12] cfq-iosched: implement cfq_group->nr_active and ->level_weight Message-ID: <20121217211517.GC1844@htj.dyndns.org> References: <1355524885-22719-1-git-send-email-tj@kernel.org> <1355524885-22719-7-git-send-email-tj@kernel.org> <20121217204609.GH7235@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121217204609.GH7235@redhat.com> 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 Hello, Vivek. On Mon, Dec 17, 2012 at 03:46:09PM -0500, Vivek Goyal wrote: > On Fri, Dec 14, 2012 at 02:41:19PM -0800, Tejun Heo wrote: > > To prepare for blkcg hierarchy support, add cfqg->nr_active and > > ->level_weight. cfqg->nr_active counts the number of active cfqgs at > > the cfqg's level and ->level_weight is sum of weights of those cfqgs. > > The level covers itself (cfqg->leaf_weight) and immediate children. > > This notion of level is really confusing. If one says "at cfqg's level" > I immediately associate with cfqg's siblings and not with cfqg's children. We can explicitly say at children's level but I think it should be enough to explain it clearly in the comment where the field is defined. > I think confusion happens because we are overloading the definition of > cfqg. It is competing with its siblings at the same time it is competing > against its child groups (on behalf of its children tasks). While I agree that part is a bit tricky, I can't think of a much better way to describe it. Any better ideas? Thanks. -- tejun