From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932157AbbE1UlF (ORCPT ); Thu, 28 May 2015 16:41:05 -0400 Received: from mail-qk0-f173.google.com ([209.85.220.173]:35128 "EHLO mail-qk0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754782AbbE1Uk4 (ORCPT ); Thu, 28 May 2015 16:40:56 -0400 Date: Thu, 28 May 2015 16:40:51 -0400 From: Tejun Heo To: Thomas Gleixner Cc: Aleksa Sarai , Peter Zijlstra , lizefan@huawei.com, mingo@redhat.com, richard@nod.at, =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org Subject: Re: [PATCH v12 8/8] cgroup: implement the PIDs subsystem Message-ID: <20150528204051.GB27479@htj.duckdns.org> References: <1431960667-26593-1-git-send-email-cyphar@cyphar.com> <1431960667-26593-9-git-send-email-cyphar@cyphar.com> <20150519080055.GA3644@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Thomas. On Tue, May 19, 2015 at 03:11:34PM +0200, Thomas Gleixner wrote: > That's complete and utter nonsense. What has the parent limit to do > with the overflow of the child limit? > > parent: limit 100 usecnt 80 > child: limit 10 usecnt 10 > > So moving anything into child is violating the constraints and has to > be refused. Anything else is just dirty hackery. And the one who's moving the process there might as well raise the limit in the child all the same. It doesn't make any difference without delegation and with delegation we need to restrict migration at the exactly same junctions. We can't delegate otherwise. And the resource limit for the delegated subtree is enforced from its parent which delegatee can't escape how it changes the configuration or moves processes around. Thanks. -- tejun