Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751402AbXBMSDc (ORCPT ); Tue, 13 Feb 2007 13:03:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751403AbXBMSDc (ORCPT ); Tue, 13 Feb 2007 13:03:32 -0500 Received: from omx1-ext.sgi.com ([192.48.179.11]:37800 "EHLO omx1.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751402AbXBMSDb (ORCPT ); Tue, 13 Feb 2007 13:03:31 -0500 Date: Tue, 13 Feb 2007 10:03:14 -0800 (PST) From: Christoph Lameter To: Andi Kleen cc: "Martin J. Bligh" , KAMEZAWA Hiroyuki , LKML , Andrew Morton , bob.picco@hp.com Subject: Re: [RFC] [PATCH] more support for memory-less-node. In-Reply-To: <200702131845.05913.ak@suse.de> Message-ID: References: <20070213155736.1131d46a.kamezawa.hiroyu@jp.fujitsu.com> <45D1F0B1.3020508@mbligh.org> <200702131845.05913.ak@suse.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1209 Lines: 30 On Tue, 13 Feb 2007, Andi Kleen wrote: > Adding NULL tests all over mm for this would seem like a clear case > of this to me. Maybe there is an alternative. We are free to number the nodes right? How about requiring the low node number to have memory and the high ones do not? F.e. have a boundary like nr_mem_nodes ? Everything above nr_mem_nodes has no memory and cannot be specified in a nodemask. Those nodes would not be visible to user space via memory policies and page migration. So the core mempolicy logic could be left untouched. The nodes above nr_mem_nodes would exist purely within the kernel. They would have proximity information (which can be used to determine neighboring memory. More flexible then the current attachment to one fixed memory node) but those node numbers could not be specified as node masks in any memory operations. This would then allow memory less nodes with I/O or cpus. The user would not be aware of these. - 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/