From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751263AbWGHHky (ORCPT ); Sat, 8 Jul 2006 03:40:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751264AbWGHHky (ORCPT ); Sat, 8 Jul 2006 03:40:54 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:11733 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S1751263AbWGHHkx (ORCPT ); Sat, 8 Jul 2006 03:40:53 -0400 Date: Sat, 8 Jul 2006 09:36:21 +0200 From: Ingo Molnar To: "linux-os (Dick Johnson)" Cc: Linus Torvalds , Krzysztof Halasa , Andrew Morton , Linux kernel , arjan@infradead.org Subject: Re: [patch] spinlocks: remove 'volatile' Message-ID: <20060708073621.GA6788@elte.hu> References: <20060707220954.GA23651@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060707220954.GA23651@elte.hu> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: -3.1 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-3.1 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_50 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 0.0 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.5000] 0.2 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Ingo Molnar wrote: > > [...] In fact, your spin-lock code already inserts "rep nops" and I > > never implied that they should be removed. I said only that "volatile" > > still needs to be used, not some macro that tells the compiler that > > everything in memory probably got trashed. [...] > > your position here does seem to make much sense to me, so please help me ^--- not > understand it. You suggest that the assembly code should be left alone. > But then why do you need the volatile keyword to begin with?