From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758746AbZBZVAf (ORCPT ); Thu, 26 Feb 2009 16:00:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755871AbZBZVAY (ORCPT ); Thu, 26 Feb 2009 16:00:24 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:43537 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755078AbZBZVAW (ORCPT ); Thu, 26 Feb 2009 16:00:22 -0500 Date: Thu, 26 Feb 2009 13:00:05 -0800 From: Andrew Morton To: KAMEZAWA Hiroyuki Cc: linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org, menage@google.com, lizf@cn.fujitsu.com, balbir@linux.vnet.ibm.com Subject: Re: [PATCH 1/2] cgroup allow subsys to set default mode of its own file Message-Id: <20090226130005.3282cb02.akpm@linux-foundation.org> In-Reply-To: <20090225163555.d2a0b24c.kamezawa.hiroyu@jp.fujitsu.com> References: <20090225163555.d2a0b24c.kamezawa.hiroyu@jp.fujitsu.com> X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.20; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 25 Feb 2009 16:35:55 +0900 KAMEZAWA Hiroyuki wrote: > When I wrote tools for maintain cgroup, I can't find which file is > writable intarfece or not via cgroup file systems. (finally, I did > dirty approach.) > IMHO, showing "this file is read-only" in explicit way is useful > for user-land (tools). In other story, a file whose name sounds read-only > may have "trigger" operation and support reseting. In this case, > "writable" is informative. Well, we have compatibility issues here. If we make this change, and people write tools which depend upon that change then those tools might break when run upon older kernels. Or they need back-compatibility additions, which increases the testing burden of those tools. One way in which we could improve this situation is to backport these changes into earlier kernels, although I don't know which versions. What do we think?