From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756523Ab3AHPvW (ORCPT ); Tue, 8 Jan 2013 10:51:22 -0500 Received: from mx1.redhat.com ([209.132.183.28]:38724 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756278Ab3AHPvV (ORCPT ); Tue, 8 Jan 2013 10:51:21 -0500 Date: Tue, 8 Jan 2013 10:51:14 -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 12/24] cfq-iosched: implement cfq_group->nr_active and ->children_weight Message-ID: <20130108155114.GC29635@redhat.com> References: <1356726946-26037-1-git-send-email-tj@kernel.org> <1356726946-26037-13-git-send-email-tj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1356726946-26037-13-git-send-email-tj@kernel.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 Fri, Dec 28, 2012 at 12:35:34PM -0800, Tejun Heo wrote: > To prepare for blkcg hierarchy support, add cfqg->nr_active and > ->children_weight. cfqg->nr_active counts the number of active cfqgs > at the cfqg's level and ->children_weight is sum of weights of those > cfqgs. The level covers itself (cfqg->leaf_weight) and immediate > children. > > The two values are updated when a cfqg enters and leaves the group > service tree. Unless the hierarchy is very deep, the added overhead > should be negligible. > > Currently, the parent is determined using cfqg_flat_parent() which > makes the root cfqg the parent of all other cfqgs. This is to make > the transition to hierarchy-aware scheduling gradual. Scheduling > logic will be converted to use cfqg->children_weight without actually > changing the behavior. When everything is ready, > blkcg_weight_parent() will be replaced with proper parent function. > > This patch doesn't introduce any behavior chagne. > > v2: s/cfqg->level_weight/cfqg->children_weight/ as per Vivek. > > Signed-off-by: Tejun Heo > Cc: Vivek Goyal Looks good to me. Acked-by: Vivek Goyal Vivek