From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262339AbVHAGYX (ORCPT ); Mon, 1 Aug 2005 02:24:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262341AbVHAGYX (ORCPT ); Mon, 1 Aug 2005 02:24:23 -0400 Received: from 66-23-228-155.clients.speedfactory.net ([66.23.228.155]:11211 "EHLO kevlar.burdell.org") by vger.kernel.org with ESMTP id S262339AbVHAGYV (ORCPT ); Mon, 1 Aug 2005 02:24:21 -0400 Date: Mon, 1 Aug 2005 02:23:22 -0400 From: Sonny Rao To: Paul Mackerras Cc: torvalds@osdl.org, akpm@osdl.org, anton@samba.org, Mike Kravetz , linux-kernel@vger.kernel.org Subject: Re: [PATCH] POWER 4 fails to boot with NUMA Message-ID: <20050801062322.GA32415@kevlar.burdell.org> References: <17133.45774.226079.790875@cargo.ozlabs.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <17133.45774.226079.790875@cargo.ozlabs.ibm.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 01, 2005 at 12:27:42AM -0500, Paul Mackerras wrote: > From: Mike Kravetz > > If CONFIG_NUMA is set, some POWER 4 systems will fail to boot. This is > because of special processing needed to handle invalid node IDs (0xffff) > on POWER 4. My previous patch to handle memory 'holes' within nodes > forgot to add this special case for POWER 4 in one place. > > In reality, I'm not sure that configuring the kernel for NUMA on POWER 4 > makes much sense. Are there POWER 4 based systems with NUMA characteristics > that are presented by the firmware? But, distros want one kernel for all > systems so NUMA is on by default in their kernels. The patch handles those > cases. IIRC, In SMP mode the NUMA topology is exported. I've tried this on a p690 and it worked correctly on older kernels (2.6.10 or 2.6.11) I also noticed a nice speedup on a few things compared to LPAR mode :-) Sonny