From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758123AbXJ0VAP (ORCPT ); Sat, 27 Oct 2007 17:00:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754195AbXJ0U75 (ORCPT ); Sat, 27 Oct 2007 16:59:57 -0400 Received: from netops-testserver-4-out.sgi.com ([192.48.171.29]:48239 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753236AbXJ0U74 (ORCPT ); Sat, 27 Oct 2007 16:59:56 -0400 Date: Sat, 27 Oct 2007 13:59:52 -0700 From: Paul Jackson To: Christoph Lameter Cc: rientjes@google.com, Lee.Schermerhorn@hp.com, akpm@linux-foundation.org, ak@suse.de, linux-kernel@vger.kernel.org Subject: Re: [patch 2/2] cpusets: add interleave_over_allowed option Message-Id: <20071027135952.2e8fb323.pj@sgi.com> In-Reply-To: References: <1193412644.5032.13.camel@localhost> <20071026120037.7b95a136.pj@sgi.com> <1193433239.5032.95.camel@localhost> <1193434278.5032.106.camel@localhost> <20071026180713.aeedfac2.pj@sgi.com> <20071026194144.6042316a.pj@sgi.com> <20071026221624.cec512da.pj@sgi.com> <20071027013656.4ffadb87.pj@sgi.com> 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 > > You have chosen (1) above, which keeps Choice A as the default. > > There can be different defaults for the user space API via libnuma that > are indepdent from the kernel API which needs to remain stable. The kernel > API can be extended but not changed. Yes - the user level code can have different defaults too. I was discussing what should be the default kernel API. > None of those [alternatives] sound appealing. Multiple processes may run > in one cpuset. Well, that would justify keeping this choice per-task. I tend to agree with that. But that doesn't justify having to specify it on each system call. In another reply David recommends against supporting Choice A at all. I'm inclined to agree with him. I'll reply there, with more thoughts. But if we did support Choice A, as a backwards compatible alternative to Choice B, I'd suggest a per-task mode, not per-system call mode. This would reduce the impact on the API of the ugly, unobvious, modal flag needed to select the optional, non kernel default, Choice B semantics. I still have low confidence that you (Christoph) and I have the same understanding of what these Choice A and B are. Hopefully you can address that, perhaps by briefly describing these choices in your words. -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.925.600.0401