Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423253AbXBHT0i (ORCPT ); Thu, 8 Feb 2007 14:26:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1423259AbXBHT0i (ORCPT ); Thu, 8 Feb 2007 14:26:38 -0500 Received: from smtp.osdl.org ([65.172.181.24]:34837 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423253AbXBHT0h (ORCPT ); Thu, 8 Feb 2007 14:26:37 -0500 Date: Thu, 8 Feb 2007 11:26:29 -0800 From: Andrew Morton To: Christoph Lameter Cc: Andi Kleen , KAMEZAWA Hiroyuki , LKML , GOTO , Christoph Lameter Subject: Re: [2.6.20][PATCH] fix mempolicy error check on a system with memory-less-node Message-Id: <20070208112629.3a4ce158.akpm@linux-foundation.org> In-Reply-To: References: <20070206202312.4f979bcf.kamezawa.hiroyu@jp.fujitsu.com> <20070207082330.d07525ec.akpm@linux-foundation.org> <200702071750.55283.ak@suse.de> <20070207094344.0efdde10.akpm@linux-foundation.org> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.17; x86_64-unknown-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: 1470 Lines: 35 On Thu, 8 Feb 2007 11:09:40 -0800 (PST) Christoph Lameter wrote: > > > > and to > > > > accurately present the machine's topology to the user without us having to > > > > go adding falsehoods like this? > > > > > > a node is a piece of memory. Without memory it doesn't make sense. > > > > Who said? I can pick up a piece of circuitry which has four CPUs and no > > RAM, wave it about then stick it in a computer. The kernel is just wrong, > > surely? > > Surely your computer has some memory so attach it to that memory (which > in a NUMA system would be one or the other node). "attach it". But it _isn't_ attached. There is no memory on this node. We seem to be saying that we should misrepresent the physical topology because the kernel doesn't handle it appropriately. > Cpu only "nodes" would mean that all memory would be off node. Meaning > whatever interconnect one has would be heavily used. Operating system and > application performance will suffer. >From this a logical step would be to change the kernel to refuse to bring memoryless nodes online at all. If that's not an approproate solution, then there must be a legtimate reason for using memoryless nodes. Which is it? - 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/