From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161479AbXBHIJI (ORCPT ); Thu, 8 Feb 2007 03:09:08 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161541AbXBHIJI (ORCPT ); Thu, 8 Feb 2007 03:09:08 -0500 Received: from smtp.osdl.org ([65.172.181.24]:60956 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161479AbXBHIJG (ORCPT ); Thu, 8 Feb 2007 03:09:06 -0500 Date: Thu, 8 Feb 2007 00:08:57 -0800 From: Andrew Morton To: Andi Kleen Cc: KAMEZAWA Hiroyuki , LKML , clameter@sgi.com, GOTO Subject: Re: [BUG][PATCH] fix mempolcy's check on a system with memory-less-node take2 Message-Id: <20070208000857.7296b94b.akpm@linux-foundation.org> In-Reply-To: <200702080903.46242.ak@suse.de> References: <20070208110606.ebf668d3.kamezawa.hiroyu@jp.fujitsu.com> <200702080849.42167.ak@suse.de> <20070208000001.9e303a1a.akpm@linux-foundation.org> <200702080903.46242.ak@suse.de> 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 On Thu, 8 Feb 2007 09:03:46 +0100 Andi Kleen wrote: > On Thursday 08 February 2007 09:00, Andrew Morton wrote: > > On Thu, 8 Feb 2007 08:49:41 +0100 Andi Kleen wrote: > > > > > > > > > This panic(hang) was found by a numa test-set on a system with 3 nodes, where > > > > node(2) was memory-less-node. > > > > > > I still think it's the wrong fix -- just get rid of the memory less node. > > > > "Let's break it even more"? > > I still don't get what you believe what would be broken then. A node with no memory is physical reality. The kernel should do its best handle and report it accurately. Pretending that the CPUs on that node are local to a different node's memory (as I understand your proposal) goes against that. > > > I expect you'll likely run into more problems with that setup anyways. > > > > What happens if he doesn't run into more problems? > > Then he's lucky. I ran into problems at least when I still had the empty > nodes some time ago on x86-64. Christoph said SN2 is doing the same. > > iirc slab blew up at least, but that might be fixed by now. But it's a little risky > because there is more code now that is node aware. > Well... I'd suggest that we try to struggle on, get it working. Is there a downside to doing that?