From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992648AbXEBDWH (ORCPT ); Tue, 1 May 2007 23:22:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2992654AbXEBDWG (ORCPT ); Tue, 1 May 2007 23:22:06 -0400 Received: from netops-testserver-4-out.sgi.com ([192.48.171.29]:52424 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2992648AbXEBDWD (ORCPT ); Tue, 1 May 2007 23:22:03 -0400 Date: Tue, 1 May 2007 20:22:01 -0700 From: Paul Jackson To: David Rientjes Cc: torvalds@linux-foundation.org, menage@google.com, clameter@cthulhu.engr.sgi.com, linux-kernel@vger.kernel.org Subject: Re: [patch] cpusets: allow empty {cpus,mems}_allowed to be set for unpopulated cpuset Message-Id: <20070501202201.6903d922.pj@sgi.com> In-Reply-To: References: Organization: SGI X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.3; i686-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 X-Mailing-List: linux-kernel@vger.kernel.org David wrote: > You currently cannot remove all cpus or mems from cpus_allowed or > mems_allowed of a cpuset. We now allow both if there are no attached > tasks. Why do you need this? It adds a little more code, and changes semantics a little bit, so I'd think it should have at least a little bit of justfication. + if (!*buf) { + cpus_clear(trialcs.cpus_allowed); Won't the above code fail if someone does: echo > /dev/cpuset/foobar/mems Just guessing, but I'd expect buf[] to contain a newline char, not just a zero length string, at this point. -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.925.600.0401