Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754826AbYGITmJ (ORCPT ); Wed, 9 Jul 2008 15:42:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751158AbYGITl5 (ORCPT ); Wed, 9 Jul 2008 15:41:57 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:56396 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751086AbYGITl4 (ORCPT ); Wed, 9 Jul 2008 15:41:56 -0400 Date: Wed, 9 Jul 2008 21:41:36 +0200 From: Ingo Molnar To: Jeremy Fitzhardinge Cc: Christoph Lameter , Mike Travis , Andrew Morton , "Eric W. Biederman" , "H. Peter Anvin" , Jack Steiner , linux-kernel@vger.kernel.org Subject: Re: [RFC 00/15] x86_64: Optimize percpu accesses Message-ID: <20080709194136.GD4804@elte.hu> References: <4874F7D9.5060607@linux-foundation.org> <4874FD52.8070000@sgi.com> <4874FFC4.7050505@linux-foundation.org> <487502BD.2020206@goop.org> <487504A8.5040000@linux-foundation.org> <487507E7.6010102@goop.org> <48750945.8000201@linux-foundation.org> <48750C6C.5090606@goop.org> <48750D96.7030407@linux-foundation.org> <4875123F.1070504@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4875123F.1070504@goop.org> 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: 1438 Lines: 34 * Jeremy Fitzhardinge wrote: >> What is remaining is the task to rename >> >> pda.Y -> Z >> >> in order to make variable references the same under both arches. >> Presumably the Z is the corresponding 32 bit variable. There are >> likely a number of cases where the transformation is trivial if we >> just identify the corresponding 32 bit equivalent. > > Yes, I understand that, but it's still pointless churn. The > intermediate step is no improvement over what was there before, and > isn't any closer to the desired final result. > > Once you've made the pda a percpu variable, and redefined all the > X_pda macros in terms of x86_X_percpu, then there's no need to touch > all the usage sites until you're *actually* going to unify something. > Touching them all just because you find "X_pda" unsightly doesn't help > anyone. Ideally every site you touch will remove a #ifdef > CONFIG_X86_64, or make two as-yet unified pieces of code closer to > unification. that makes sense. Does everyone agree on #1-#2-#3 and then gradual elimination of most pda members (without going through an intermediate renaming of pda members) being the way to go? 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/