From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 06/12] cfq-iosched: implement cfq_group->nr_active and ->level_weight Date: Mon, 17 Dec 2012 13:15:17 -0800 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 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=kWoESnuTDhOIb8ZWQfIpg+ikxPonIzM2/aH4ELpB/Lw=; b=FACdrStbrXFVjGqloDprGqboyE1sBuurUmUdds8mguVqb5Aa39lvLoLnA8H0WCDSqE mWwwJBp4cL2dt6xpyolJ/m3475MR0RnzxfW+oJuD845En1PDelP6dZvsypC1Pw7WQTdr ug+vGEvWTL5kLXgMg3vk1pCNDkcYaooiaqSncEr//+65XywRewrhrv3m/iEoK+mjmXO7 SnB8DyAp0KpDROebEtqHuyCoY+PIteifbUW7KQyg4kqX2IQtrNMJf06mCCwLnVObfDjn wIAdOSBxpP5JENLfcBzik5uHGyZb892JbACJvdrxBufBU0cUCab5yLG0kIKChKdOfs43 Apeg== Content-Disposition: inline In-Reply-To: <20121217204609.GH7235-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Vivek Goyal Cc: lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org, axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, ctalbott-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, rni-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.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