Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754089AbZI3U62 (ORCPT ); Wed, 30 Sep 2009 16:58:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752068AbZI3U62 (ORCPT ); Wed, 30 Sep 2009 16:58:28 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:48153 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752034AbZI3U61 (ORCPT ); Wed, 30 Sep 2009 16:58:27 -0400 Date: Wed, 30 Sep 2009 22:58:08 +0200 From: Ingo Molnar To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, eric.dumazet@gmail.com, arjan@linux.intel.com, torvalds@linux-foundation.org, johnstul@us.ibm.com, a.p.zijlstra@chello.nl, schwidefsky@de.ibm.com, arjan@infradead.org, tglx@linutronix.de Cc: linux-tip-commits@vger.kernel.org Subject: Re: [tip:sched/urgent] x86: Provide an alternative() based cmpxchg64() Message-ID: <20090930205808.GC24862@elte.hu> References: <20090930170754.0886ff2e@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) 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=3.2.5 -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: 1280 Lines: 33 * tip-bot for Arjan van de Ven wrote: > Commit-ID: e87aaa7b6d80474ec07a2d2be3f50ef574ffe36c > Gitweb: http://git.kernel.org/tip/e87aaa7b6d80474ec07a2d2be3f50ef574ffe36c > Author: Arjan van de Ven > AuthorDate: Wed, 30 Sep 2009 17:07:54 +0200 > Committer: Ingo Molnar > CommitDate: Wed, 30 Sep 2009 22:35:44 +0200 > > x86: Provide an alternative() based cmpxchg64() > > cmpxchg64() today generates, to quote Linus, "barf bag" code. > > cmpxchg64() is about to get used in the scheduler to a bug there, > but it's a prerequisite that cmpxchg64() first be made non-sucking. > > This patch turns cmpxchg64() into an efficient implementation that > uses the alternative() mechanism to just use the raw instruction on > all modern systens The changelog above has 3 typos so i fixed that. The push will generate the hopefully-final version of these patches. Note, i slightly updated Linus's version of the old-CPU emu code with Eric's micro-optimization. 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/