Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964776AbVISWsN (ORCPT ); Mon, 19 Sep 2005 18:48:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964778AbVISWsN (ORCPT ); Mon, 19 Sep 2005 18:48:13 -0400 Received: from smtp.osdl.org ([65.172.181.4]:55976 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S964776AbVISWsM (ORCPT ); Mon, 19 Sep 2005 18:48:12 -0400 Date: Mon, 19 Sep 2005 15:48:13 -0700 From: Andrew Morton To: Andi Kleen Cc: clameter@engr.sgi.com, torvalds@osdl.org, linux-kernel@vger.kernel.org Subject: Re: NUMA mempolicy /proc code in mainline shouldn't have been merged Message-Id: <20050919154813.52f5b706.akpm@osdl.org> In-Reply-To: <200509192356.56300.ak@suse.de> References: <200509101120.19236.ak@suse.de> <20050919194038.GB12810@verdi.suse.de> <200509192356.56300.ak@suse.de> X-Mailer: Sylpheed version 1.0.0 (GTK+ 1.2.10; i386-vine-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 Content-Length: 2049 Lines: 44 Andi Kleen wrote: > > On Monday 19 September 2005 23:32, Christoph Lameter wrote: > > On Mon, 19 Sep 2005, Andi Kleen wrote: > > > On Mon, Sep 19, 2005 at 10:11:20AM -0700, Christoph Lameter wrote: > > > > However, one still does not know which memory section (vma) is > > > > allocated on which nodes. And this may be important since critical data > > > > may need to > > > > > > Maybe. Well sure of things could be maybe important. Or maybe not. > > > Doesn't seem like a particularly strong case to add a lot of ugly > > > code though. > > > > We gradually need to fix the deficiencies of the policy layer. Calling > > fixes "ugly code" and refusing to discuss solutions does not help anyone. > > I'm happy to discuss solutions given a clear use case what you want > to do, why you want to do it etc. Yes. A clear explanation of the requirements and usecases based on real-world experience from real-world users and/or application developers. I asked Christoph for that last week. The answers were, iirc, a bit half-baked, but believeable. > > Have you ever had the challenge to work with large HPC applications on a > > large NUMA system? > > Ah - my code is better because my credentials are better. No fair. I've never worked on big HPC systems and any feedback from the field which Christoph can provide is really important in helping us understand what features the kernel needs to offer. I would expect that SGI engineering have a better understanding of HPC users' needs than pretty much anyone else in the world. It's a shame that SGI engineering aren't better at communicating those needs to wee little kernel developers. And we need to get better at this because, as you say, external policy control is going to be a ton harder to swallow than /proc/pid/numa_maps. - 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/