From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754580Ab0AMCPO (ORCPT ); Tue, 12 Jan 2010 21:15:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753891Ab0AMCPN (ORCPT ); Tue, 12 Jan 2010 21:15:13 -0500 Received: from hera.kernel.org ([140.211.167.34]:33911 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753578Ab0AMCPL (ORCPT ); Tue, 12 Jan 2010 21:15:11 -0500 Message-ID: <4B4D2C44.2060709@kernel.org> Date: Tue, 12 Jan 2010 18:13:24 -0800 From: Yinghai Lu User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.5) Gecko/20091130 SUSE/3.0.0-1.1.1 Thunderbird/3.0 MIME-Version: 1.0 To: Suresh Siddha CC: Linus Torvalds , "ananth@in.ibm.com" , Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , Andrew Morton , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH -v2 5/5] x86: use dmi check to treat disabled cpus as hotplug cpus. References: <1263338274-6485-1-git-send-email-yinghai@kernel.org> <1263338274-6485-5-git-send-email-yinghai@kernel.org> <1263340563.2854.1011.camel@sbs-t61.sc.intel.com> <4B4D0E39.10200@kernel.org> <1263347315.2854.1296.camel@sbs-t61.sc.intel.com> <4B4D2811.7000001@kernel.org> <1263348363.2854.1360.camel@sbs-t61.sc.intel.com> In-Reply-To: <1263348363.2854.1360.camel@sbs-t61.sc.intel.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/12/2010 06:06 PM, Suresh Siddha wrote: > On Tue, 2010-01-12 at 17:55 -0800, Yinghai Lu wrote: >> you mean this blacklist could be too long? > > yes. > >> >> switch to whitelist for the box can treat disabled cpus as hotplug >> cpus? > > Do we really need all this? Systems which support physical hotplug > typically have lot's of cpu's (mostly will have atleast > 8). Even if we > really need to identify, then perhaps we can check if ACPI has any hints > regarding the physical hotplug support at boot time (we should check > with Andi Kleen or Len Brown on this). > > For now, I think we can keep it simple by using the detected enabled > cpu's. sth like this ? --- arch/x86/kernel/smpboot.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) Index: linux-2.6/arch/x86/kernel/smpboot.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/smpboot.c +++ linux-2.6/arch/x86/kernel/smpboot.c @@ -1190,7 +1190,6 @@ early_param("possible_cpus", _setup_poss * - Ashok Raj * * Three ways to find out the number of additional hotplug CPUs: - * - If the BIOS specified disabled CPUs in ACPI/mptables use that. * - The user can overwrite it with possible_cpus=NUM * - Otherwise don't reserve additional CPUs. * We do this because additional CPUs waste a lot of memory. @@ -1205,7 +1204,7 @@ __init void prefill_possible_map(void) num_processors = 1; if (setup_possible_cpus == -1) - possible = num_processors + disabled_cpus; + possible = num_processors; else possible = setup_possible_cpus;