Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758358AbaJ3HHg (ORCPT ); Thu, 30 Oct 2014 03:07:36 -0400 Received: from casper.infradead.org ([85.118.1.10]:49836 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752732AbaJ3HHf (ORCPT ); Thu, 30 Oct 2014 03:07:35 -0400 Date: Thu, 30 Oct 2014 08:07:25 +0100 From: Peter Zijlstra To: Tejun Heo Cc: Vikas Shivappa , "Auld, Will" , Matt Fleming , Vikas Shivappa , "linux-kernel@vger.kernel.org" , "Fleming, Matt" Subject: Re: Cache Allocation Technology Design Message-ID: <20141030070725.GG3337@twins.programming.kicks-ass.net> References: <20141020161855.GF12020@console-pimps.org> <20141024105306.GI12706@worktop.programming.kicks-ass.net> <20141028232215.GO12020@console-pimps.org> <20141029081640.GT3337@twins.programming.kicks-ass.net> <20141029124834.GQ12020@console-pimps.org> <20141029134526.GC3337@twins.programming.kicks-ass.net> <96EC5A4F3149B74492D2D9B9B1602C27349EEB88@ORSMSX105.amr.corp.intel.com> <20141029172845.GP12706@worktop.programming.kicks-ass.net> <20141029182234.GA13393@mtj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141029182234.GA13393@mtj.dyndns.org> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 29, 2014 at 02:22:34PM -0400, Tejun Heo wrote: > On Wed, Oct 29, 2014 at 10:41:47AM -0700, Vikas Shivappa wrote: > > Was wondering if it is a requirement of the 'full hierarchy' for the child > > to inherit the cbm of parent ? . > > Alternately we can allocate the CLOSid when a cgroup is created and have an > > empty cbm - but dont let the tasks to be added unless the user assigns a > > Please don't do that. All controllers must be fully hierarchical, With you so far. > shouldn't fail task migration If this means echo $tid > tasks, then sorry we can't do. There is a limited number of hardware resources backing this thing. At some point they're consumed and something must give. So either we fail mkdir, but that means allocating CLOS IDs for possibly empty cgroups, or we allocate on demand which means failing task assignment. The same -- albeit for a different reason -- is true of the RT sched groups, we simply cannot instantiate them such that tasks can join, sysads _have_ to configure them before we can add tasks to them. > and always allow execution of member tasks. If we accept tasks, they'll run. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/