Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758143AbZKDXhv (ORCPT ); Wed, 4 Nov 2009 18:37:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757241AbZKDXhv (ORCPT ); Wed, 4 Nov 2009 18:37:51 -0500 Received: from e39.co.us.ibm.com ([32.97.110.160]:39000 "EHLO e39.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755015AbZKDXhu (ORCPT ); Wed, 4 Nov 2009 18:37:50 -0500 Date: Wed, 4 Nov 2009 15:37:45 -0800 From: Matt Helsley To: Paul Menage Cc: Matt Helsley , KAMEZAWA Hiroyuki , balbir@linux.vnet.ibm.com, Dhaval Giani , containers@lists.linux-foundation.org, "linux-kernel@vger.kernel.org" , Jan@smtp1.linux-foundation.org, Bharata B Rao , libcg-devel , Safranek Subject: Re: [RFC] Mount point suggestions for cgroup Message-ID: <20091104233745.GB3668@count0.beaverton.ibm.com> References: <20091104063005.GC3560@balbir.in.ibm.com> <20091104154024.0b8f6123.kamezawa.hiroyu@jp.fujitsu.com> <20091104173517.GA3668@count0.beaverton.ibm.com> <6599ad830911041325i9b309a7y4d912d6be7ddbdd9@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6599ad830911041325i9b309a7y4d912d6be7ddbdd9@mail.gmail.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1726 Lines: 34 On Wed, Nov 04, 2009 at 01:25:46PM -0800, Paul Menage wrote: > On Wed, Nov 4, 2009 at 9:35 AM, Matt Helsley wrote: > > > > If anything, "standardizing" the mount point(s) will likely provide a false > > sense of uniformity and we'll get some bad userspace scripts/tools that > > break when "nonstandard" usage appears. Leaving the mount point undefined > > forces anyone writing scripts or tools to consider whether they want to be > > portable and, if so, the proper way to find the cgroup hierarchies they need > > to manipulate. > > Scanning /proc/mounts to find the relevant mount locations is pretty > simple, for code that's just wanting to use existing cgroup mounts. > But for the code that sets up mounts in the first place, its probably > helpful to have recommendations of suitable locations. If the tool set up the mounts in the first place then there's nothing gained, as far as the code is concerned, by standardizing the location. It could just as easily make a temporary directory and put it there. If it's specified in an /etc file by the user then standardization gets us nothing but inflexibility. The user knows where it is (they set it) and the code knows where it is (via /proc OR /etc). Recommending default locations seems helpful only so that users can inspect what the code does. Blessing one location as the "standard, one, true location" for code to use -- via FHS/LSB/whatnot -- seems like asking for trouble. Cheers, -Matt -- 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/