Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754576AbZA0Lh6 (ORCPT ); Tue, 27 Jan 2009 06:37:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752847AbZA0Lht (ORCPT ); Tue, 27 Jan 2009 06:37:49 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:46159 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752741AbZA0Lhs (ORCPT ); Tue, 27 Jan 2009 06:37:48 -0500 Date: Tue, 27 Jan 2009 12:37:34 +0100 From: Ingo Molnar To: Tejun Heo Cc: James Bottomley , Brian Gerst , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2 #tj-percpu] x86: fix build breakage on voyage Message-ID: <20090127113734.GA28249@elte.hu> References: <20090126103243.GA31307@elte.hu> <1232977445-11815-1-git-send-email-brgerst@gmail.com> <20090126141832.GA31442@elte.hu> <497E6B34.1020508@kernel.org> <497E8778.9060503@gmail.com> <1233032609.3248.78.camel@localhost.localdomain> <497E9B9D.4010102@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <497E9B9D.4010102@gmail.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 Content-Length: 1336 Lines: 39 * Tejun Heo wrote: > From: James Bottomley > > Impact: build fix > > x86_cpu_to_apicid and x86_bios_cpu_apicid aren't defined for voyage. > Earlier patch forgot to conditionalize early percpu clearing. Fix it. > +#ifdef CONFIG_X86_LOCAL_APIC > early_per_cpu_ptr(x86_cpu_to_apicid) = NULL; > early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL; > +#endif That patch is not acceptable - it is ugly and it adds another set of #ifdefs to an already complex piece of code. As i explained it to James in recent threads, the clean and acceptable solution to this class of problems is to switch Voyager away from that fragile subarch code to proper generic x86 code. (just like we did it for other subarchitectures) There is nothing in Voyager that justifies special treatment in the area of x86 percpu code. This is one of the mails that explains the principles: http://lkml.indiana.edu/hypermail/linux/kernel/0901.2/00954.html Or - if there's no time/interest in doing that, we can mark Voyager as CONFIG_BROKEN. Ingo -- 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/