Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755396Ab0G1PqY (ORCPT ); Wed, 28 Jul 2010 11:46:24 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:38712 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751136Ab0G1PqX (ORCPT ); Wed, 28 Jul 2010 11:46:23 -0400 MIME-Version: 1.0 In-Reply-To: References: <4C4F7277.8050306@zytor.com> From: Linus Torvalds Date: Wed, 28 Jul 2010 08:45:30 -0700 Message-ID: Subject: Re: [tip:x86/urgent] x86: Add memory modify constraints to xchg() and cmpxchg() To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, glommer@redhat.com, alan@lxorguk.ukuu.org.uk, zamsden@redhat.com, stable@kernel.org, mtosatti@redhat.com, gregkh@suse.de, peter@palfrader.org, tglx@linutronix.de, avi@redhat.com Cc: linux-tip-commits@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 801 Lines: 19 On Tue, Jul 27, 2010 at 10:33 PM, tip-bot for H. Peter Anvin wrote: > > x86: Add memory modify constraints to xchg() and cmpxchg() Ack. I assume this doesn't really change the code generated? At least not with a gcc that honors the whole memory clobber thing properly? I also suspect that we can/should get rid of the __xg() thing - it was there just to make sure gcc didn't see the memory read as a single word and tried to optimize it. With the "+m" it probably doesn't matter any more (don't know if it ever did) Linus -- 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/