From: Tejun Heo Subject: Re: [RFC] cgroup TODOs Date: Fri, 14 Sep 2012 11:53:24 -0700 Message-ID: <20120914185324.GI17747@google.com> References: <20120913205827.GO7677@google.com> <20120914180754.GF6221@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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=2rQ0/R3UHNpvHST/O5qT5Bjyf3SL7b0JvBc1TGnNsIo=; b=b14CpNb9mHFyFncViaasgP5AXYCroFgjGOmyCYGlS97ViZ2JvL9GybQc+FQ3mG473k T9jziQxPy9yV7xOGD7vrk+Wu5q5FQP09Ppxk3XuD6gLRtu3lh8gI64k6L7muGu8Q0ixJ V3OLJXZbt4IJZbpW7bTs8YREpVlRXM730MnCUGLCjRSKLrXsAJfjf0c9AT1xspGpnq8L ctSnsac7cWQgt4VWNSlncOc5KoThUoXtpmAnkLAxsUuEwzgNJNp3IuwbS5Tg4Ffio3nZ dK21yVLn7FNZmWAXQpYx8CCkM3qgBaDiRcGK+Yi7iORRJ9OiEl2LURE/cc+iwh8jvScj BsUQ== Content-Disposition: inline In-Reply-To: <20120914180754.GF6221-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Vivek Goyal Cc: Neil Horman , containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Serge Hallyn , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Michal Hocko , Paul Mackerras , "Aneesh Kumar K.V" , Arnaldo Carvalho de Melo , Johannes Weiner , Thomas Graf , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Paul Turner , Ingo Molnar Hello, Vivek. On Fri, Sep 14, 2012 at 02:07:54PM -0400, Vivek Goyal wrote: > I am curious that why are you planning to provide capability of controller > specific view of hierarchy. To me it sounds pretty close to having > separate hierarchies per controller. Just that it is a little more > restricted configuration. I think it's a lot less crazy and gives us a way to bind a resource to a set of controller cgroups regardless which task is looking at it, which is something we're sorely missing now. > IOW, who is is the user of this functionality and who is asking for it. > Can we go all out where all controllers have only one hierarchy view. I think the issue is that controllers inherently have overhead and behavior alterations depending on the tree organization. At least from the usage I see from google which uses nested cgroups extensively, at least that level of flexibility seems necessary. In addition, for some resources, granularity beyond certain point simply doesn't work. Per-service granularity might make sense for cpu but applying it by default would be silly for blkio. Thanks. -- tejun