From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [RFD] cgroup: about multiple hierarchies Date: Wed, 22 Feb 2012 10:01:12 -0800 Message-ID: <20120222180112.GB32694@google.com> References: <20120221211938.GE12236@google.com> <1329917459.24994.14.camel@twins> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=dTAYW+LnWvlfBZzAhscTX+/jGdW4DhGO+IeDKexvgYA=; b=s8O05C/R92a1OlZkU2WHaYnhUX7LAuS+hHVkmM4x5w1qUbzm0tP26CAf9zbea+7oTj OxIzT3zzqWzUk033K8hsrAlIV98FaBR3wplOdrBeavq37Ja7O0HS1Y9co3VRzCwg5Kw4 91iJAhL8Qo26jRragj3hxeuKBEgclfF8xctv4= Content-Disposition: inline In-Reply-To: <1329917459.24994.14.camel@twins> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Peter Zijlstra Cc: Li Zefan , containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andrew Morton , Kay Sievers , Lennart Poettering , Frederic Weisbecker , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Christoph Hellwig Hey, Peter. On Wed, Feb 22, 2012 at 02:30:59PM +0100, Peter Zijlstra wrote: > FWIW I'm all for ripping the orthogonal hierarchy crap out, I hate it > just about as much as you do judging from your write-up. I just don't get why it's there. Maybe, there can be some remote use cases where orthogonal hierarchies can be useful but structuring whole cgroup around that seems really extreme. > I'm not sure on your process hierarchy pie though, I rather like being > able to assign tasks to cgroups of my making without having to mirror > that in the process hierarchy. The only question is whether we want to allow cgroup hierarchy to be completely orthogonal from process tree structure, which I don't think is a good idea. It shouldn't affect trivial use cases. If not explicitly configured, all tasks would live in a single root cgroup - much like every process would belong to the same session if nobody does setsid() since boot (or container). I don't know how the implementation would turn out and it may as well stay separate as it is now but I still think the topology should match pstree. Thanks. -- tejun