From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759742AbZA3AJp (ORCPT ); Thu, 29 Jan 2009 19:09:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754870AbZA3AJg (ORCPT ); Thu, 29 Jan 2009 19:09:36 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:57747 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754837AbZA3AJg (ORCPT ); Thu, 29 Jan 2009 19:09:36 -0500 Date: Fri, 30 Jan 2009 01:09:16 +0100 From: Ingo Molnar To: Randy Dunlap Cc: Yinghai Lu , Thomas Gleixner , "H. Peter Anvin" , Andrew Morton , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] x86: allow 8 more cpus could be used Message-ID: <20090130000916.GA332@elte.hu> References: <49822B1D.9070708@kernel.org> <20090129224236.GD1465@elte.hu> <49823166.4010702@oracle.com> <20090129231259.GB29611@elte.hu> <49823869.4010406@oracle.com> <20090129232207.GC30601@elte.hu> <49823AD7.3000502@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49823AD7.3000502@oracle.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Randy Dunlap wrote: > Ingo Molnar wrote: > > * Randy Dunlap wrote: > > > >> Ingo Molnar wrote: > >>> * Randy Dunlap wrote: > >>> > >>>> Ingo Molnar wrote: > >>>>> * Yinghai Lu wrote: > >>>>> > >>>>>> Impact: fix left out MARCO > >>>>>> > >>>>>> X86_PC will be always enabled. so need to check if we have bigsmp > >>>>>> support built in before cut off more than 8 cpus. > >>>>> ah, that's a leftover reference to X86_PC. It can now be removed, together > >>>>> with the Kconfig X86_PC option. > >>>>> > >>>>>> -#if defined(CONFIG_X86_PC) && defined(CONFIG_X86_32) > >>>>>> +#if defined(CONFIG_X86_PC) && !defined(CONFIG_X86_BIGSMP) > >>>>>> if (def_to_bigsmp && nr_cpu_ids > 8) { > >>>>>> unsigned int cpu; > >>>>>> unsigned nr; > >>>>> Could you please send a patch that removes both X86_PC and X86_BIGSMP - > >>>>> and removes the above cutoff code too, so that it will be built-in all the > >>>>> time? > >>>> and at what cost, please? > >>> the size difference between a bigsmp and a normal-smp x86 defconfig kernel > >>> is 0.011%. Zero difference on a UP kernel. (And UP is what most of the > >>> ultra-embedded systems are using) > >> That's static size? how about cpu and apic table space? > > > > What do you mean? What is your point and what is your exact question? > > There used to be large CPU and APIC tables (depending on the MAX number > of these devices that are supported in a kernel). Are those gone? ah, ok. No, there's no such dependency on CONFIG_X86_BIGSMP. The total size difference is around 900 bytes on the defconfig kernel - and that includes the APIC tables too. > If not, then I agree with YH and CONFIG_BIGSMP is still needed/wanted by > small systems. It's not a size issue - but we can still keep the option. Ingo