From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932340AbWAZOfM (ORCPT ); Thu, 26 Jan 2006 09:35:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932342AbWAZOfL (ORCPT ); Thu, 26 Jan 2006 09:35:11 -0500 Received: from cantor.suse.de ([195.135.220.2]:22408 "EHLO mx1.suse.de") by vger.kernel.org with ESMTP id S932340AbWAZOfK (ORCPT ); Thu, 26 Jan 2006 09:35:10 -0500 From: Andi Kleen To: Ashok Raj Subject: Re: Dont record local apic ids when they are disabled in MADT Date: Thu, 26 Jan 2006 15:34:54 +0100 User-Agent: KMail/1.8.2 Cc: akpm@osdl.org, linux-kernel@vger.kernel.org, ak@muc.de, ronald@hummelink.net, DiegoCG@teleline.es, venkatesh.pallipadi@intel.com, anil.s.keshavamurthy@intel.com References: <20060126054842.A11917@unix-os.sc.intel.com> <200601261455.11981.ak@suse.de> <20060126061034.A12261@unix-os.sc.intel.com> In-Reply-To: <20060126061034.A12261@unix-os.sc.intel.com> MIME-Version: 1.0 Content-Disposition: inline Message-Id: <200601261534.55620.ak@suse.de> Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 26 January 2006 15:10, Ashok Raj wrote: > On Thu, Jan 26, 2006 at 02:55:11PM +0100, Andi Kleen wrote: > > On Thursday 26 January 2006 14:48, Ashok Raj wrote: > > > Hi Andrew, > > > > > > We had added additional_cpus=xx for x86_64, but apparently there were some > > > BIOSs that had duplicate apic ids when they were reported disabled. > > > > > > It seems fair not to record them, this was causing some bad behaviour due to > > > the duplicate apic id. More details in the bugzilla recorded in the log. > > > > This means CPU hotplug will require additional non existing code again - or who > > will set up the APIC IDs etc. for the new CPUs then? > > > The ACPI hotplug code already would refresh this apic id when the notify > for CPU hotplug is processed. How? All the code who could do this is __init. > (although i would say we tested this only on ia64 so far, the code is > generic to x86_64 as well, but i havent gone around testing physical hotplug > via emulation patches we have internally) I doubt it will work on x86-64. And you're breaking the CPU hotplug spec in Documentation/x86-64/cpu-hotplug-spec. I think the BIOS bugs need to be workarounded without breaking that. -Andi