From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268360AbUH2XBw (ORCPT ); Sun, 29 Aug 2004 19:01:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268365AbUH2XBw (ORCPT ); Sun, 29 Aug 2004 19:01:52 -0400 Received: from stat16.steeleye.com ([209.192.50.48]:37593 "EHLO hancock.sc.steeleye.com") by vger.kernel.org with ESMTP id S268360AbUH2XAV (ORCPT ); Sun, 29 Aug 2004 19:00:21 -0400 Subject: Re: SMP Panic caused by [PATCH] sched: consolidate sched domains From: James Bottomley To: Nathan Lynch Cc: Jesse Barnes , Andrew Morton , Linus Torvalds , Matthew Dobson , Nick Piggin , Linux Kernel In-Reply-To: <1093801714.29741.15.camel@booger> References: <1093786747.1708.8.camel@mulgrave> <200408290948.06473.jbarnes@engr.sgi.com> <1093798704.10973.15.camel@mulgrave> <200408291007.50553.jbarnes@engr.sgi.com> <1093800241.1708.25.camel@mulgrave> <1093801714.29741.15.camel@booger> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.8 (1.0.8-9) Date: 29 Aug 2004 18:59:49 -0400 Message-Id: <1093820392.1708.73.camel@mulgrave> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2004-08-29 at 13:48, Nathan Lynch wrote: > I've got a patch which reinitializes sched domains at cpu hotplug time. > We need something like this on ppc64 for partitioned systems (we run > into the same issue when adding a cpu which wasn't present at boot). I > had been waiting to post it until some cpu hotplug issues with preempt > were solved, but it seems it would help the case of hotplugging > secondary cpus at boot, so I'll submit that soon. Well, but the only time you should need to alter a priori knowledge like this is if you're actually altering the NUMA topology, isn't it? Simply bringing up a CPU in a known numa system shouldn't need to alter scheduling domain information on CPU hotplug because the cpu automatically becomes part of an existing domain (where it was originally accounted for as missing). However, if you hotplug a numa node, then you're adding to the scheduling domain and would thus need to initialise the new node and its CPUs. James