From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753346AbbCITv0 (ORCPT ); Mon, 9 Mar 2015 15:51:26 -0400 Received: from mail-qc0-f172.google.com ([209.85.216.172]:38258 "EHLO mail-qc0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752110AbbCITvV (ORCPT ); Mon, 9 Mar 2015 15:51:21 -0400 Date: Mon, 9 Mar 2015 15:51:17 -0400 From: Tejun Heo To: Austin S Hemmelgarn Cc: Aleksa Sarai , lizefan@huawei.com, mingo@redhat.com, peterz@infradead.org, richard@nod.at, fweisbec@gmail.com, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org Subject: Re: [PATCH v4 2/2] cgroups: add a pids subsystem Message-ID: <20150309195117.GW13283@htj.duckdns.org> References: <1424660891-12719-1-git-send-email-cyphar@cyphar.com> <1425606357-6337-1-git-send-email-cyphar@cyphar.com> <1425606357-6337-3-git-send-email-cyphar@cyphar.com> <20150309033405.GE13283@htj.duckdns.org> <54FDED43.4050908@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54FDED43.4050908@gmail.com> 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, Austin. On Mon, Mar 09, 2015 at 02:58:11PM -0400, Austin S Hemmelgarn wrote: > On 2015-03-08 23:34, Tejun Heo wrote: > > > >Does pids limit make sense in the root cgroup? > > > I would say it kind of does, although I would just expect it to track > /proc/sys/kernel/pid_max (either as a read-only value, or as an alternative > way to set it). I don't think that's a good idea. It doesn't add anything while putting pids controller in conflict with how other controllers handle the root cgroup. Furthermore, I don't think it's generally a good idea to add things because it may help convenience in some cases, which is exactly the case here. Why add non-orthogonal component when the only reason is "yeah, it may be a bit more convenient in some imaginary cases"? We'd be restricting the design space we can move inside for no good reason. Thanks. -- tejun