Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752332Ab1DUF5K (ORCPT ); Thu, 21 Apr 2011 01:57:10 -0400 Received: from mail-bw0-f46.google.com ([209.85.214.46]:32915 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752231Ab1DUF46 (ORCPT ); Thu, 21 Apr 2011 01:56:58 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=a69YqAFsSu/WYxgKteHMaW0fQu+LsX8+c03Y7+RPMAUG6wbtK7FT1JdrWWyxOtsNUN zzPfKd1DCert1fSWPHJkCVezSps+lwAGjw+FCDkBS/+IFDLXhmjOvjW12BKnJmecCTfK tbsmh116MSUjojYkQT7TojmN6LVm+4K6V35i8= Date: Thu, 21 Apr 2011 08:04:17 +0200 From: Andreas Herrmann To: KOSAKI Motohiro Cc: Linus Torvalds , Linux Kernel Mailing List , Ingo Molnar , Tejun Heo Subject: Re: Linux 2.6.39-rc4 (regression: NUMA on multi-node CPUs broken) Message-ID: <20110421060417.GA7046@loge> References: <20110420153907.GA9000@alberich.amd.com> <20110421110452.7323.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110421110452.7323.A69D9226@jp.fujitsu.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2517 Lines: 71 On Thu, Apr 21, 2011 at 11:04:27AM +0900, KOSAKI Motohiro wrote: > > Following patch breaks real NUMA on multi-node CPUs like AMD > > Magny-Cours and should be reverted (or changed to just take effect in > > case of numa=fake): > > > > commit 7d6b46707f2491a94f4bd3b4329d2d7f809e9368 > > Author: KOSAKI Motohiro > > Date: Fri Apr 15 20:39:01 2011 +0900 > > > > x86, NUMA: Fix fakenuma boot failure > > > > ... > > > > Thus, this patch implements a reassignment of node-ids if buggy firmware > > or numa emulation makes wrong cpu node map. Tt enforce all logical cpus > > in the same physical cpu share the same node. > > > > ... > > > > +static void __cpuinit check_cpu_siblings_on_same_node(int cpu1, int cpu2) > > +{ > > + int node1 = early_cpu_to_node(cpu1); > > + int node2 = early_cpu_to_node(cpu2); > > + > > + /* > > + * Our CPU scheduler assumes all logical cpus in the same physical cpu > > + * share the same node. But, buggy ACPI or NUMA emulation might assign > > + * them to different node. Fix it. > > + */ > > > > ... > > > > This is a false assumption. Magny-Cours has two nodes in the same > > physical package. The scheduler was (kind of) fixed to work around > > this boot problem for multi-node CPUs (with 2.6.32). > > I agree we have to fix this ASAP. I also think we have to avoid reintroduce > the same again. Can you please tell me the commit-id of this one? It's commit 5a925b4282d7f805deafde62001a83dbaf8be275 Author: Andreas Herrmann Date: Thu Sep 3 09:44:28 2009 +0200 x86, sched: Workaround broken sched domain creation for AMD Magny-Cours > > If this is also > > an issue with wrong cpu node maps in case of NUMA emulation this might > > be fixed similar or this quirk should only be applied in case of NUMA > > emulation. > > Indeed. > > Tejun, Do you remember I sent numa emulation specific patch at first. now > I'm beside with Andreas. Because I bet current numa fallback code (you > pointed out one) has no user. > > Or, please let us know if you have an alternative patch. > > Attached revert and fakenuma spefic fix patches. Andreas -- 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/