From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: cgroup: status-quo and userland efforts Date: Mon, 8 Apr 2013 11:26:49 -0700 Message-ID: <20130408182649.GJ3021@htj.dyndns.org> References: <20130406012159.GA17159@mtj.dyndns.org> <5162CA21.4060108@parallels.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=x-received:sender:date:from:to:cc:subject:message-id:references :mime-version:content-type:content-disposition:in-reply-to :user-agent; bh=IgF36XrxT54fgOuTq/0v8qmxU2RvqT6KRU7Sg1GuLBM=; b=J0zQGt2QRAOPwckFagRkn2u93a74+i3Nq1UiljZuNAmCOOr3i9O74jAKE4nZ8I5ueA GN8UWwtT2CDVvsRRGDASYW4ERDOYm3DE97VT4rFCfyOxFkX9e1wTiWy65fQ39GbphlT4 7I22IcV6FcbEScU+u5IXh9z844OX05Lt9PqqcZwEeb2TcjyARkVNoLlEOqxWZDoP3LVX 1kY7aXPPdscnqQOpWpNcOxINOy7323wcrv402OEqiTi6w/NUFzdI9yQm7z0YMeYxEqjY M4XZWWg2uI6MWmquZejCO8ivmUHjj6xoNj8f15mUvJJyxKS6VRINaDTgFOEOqNpiOcaJ nmKQ== Content-Disposition: inline In-Reply-To: <5162CA21.4060108-bzQdu9zFT3WakBO8gow8eQ@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: Glauber Costa Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Kay Sievers , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, lpoetter-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, jpoimboe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dhaval.giani-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, workman-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org Hey, Glauber. On Mon, Apr 08, 2013 at 05:46:09PM +0400, Glauber Costa wrote: > On 04/06/2013 05:21 AM, Tejun Heo wrote: > > Hello, guys. > > Hello Tejun, how are you? I'm doing okay. :) > > Status-quo > > ========== > > > tl;did read; > > This is mostly sensible. There is still one problem that we hadn't yet > had the bandwidth to tackle that should be added to your official TODO list. > > The cpu cgroup needs a real-time timeslice to accept real time tasks. It > defaults to 0, meaning that a newly created cpu cgroup cannot accept > tasks (rt tasks) without the user having to manually configure it. > As far as I know, this problem hasn't yet been fixed. > > The fix of course, is as trivial as setting a new value instead of 0 as > a default. The complication lies in determining which value should that be. > > There are many things that we should ask from a controller to implement > in order to be able to handle fully joint hierarchies. One of them, > IMHO, is that if you drop a task into a newly created cgroup it should > run without the user having to do anything for it. Yeap, definitely. cpuset has similar problems (Li, help us!). For the controllers which are showing behaviors which don't allow sharing a single hierarchy, I think the solution is to implement an alternate behavior which can be flipped on mount time and force the switch flipped when mounting unified hierarchy, so that we don't disturb the existing users while pushing for more consistent behavior. Thanks. -- tejun