Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751394AbWCCVey (ORCPT ); Fri, 3 Mar 2006 16:34:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751370AbWCCVey (ORCPT ); Fri, 3 Mar 2006 16:34:54 -0500 Received: from smtp.osdl.org ([65.172.181.4]:54934 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1751394AbWCCVex (ORCPT ); Fri, 3 Mar 2006 16:34:53 -0500 Date: Fri, 3 Mar 2006 13:34:17 -0800 (PST) From: Linus Torvalds To: David Howells cc: akpm@osdl.org, ak@suse.de, mingo@redhat.com, jblunck@suse.de, bcrl@linux.intel.com, matthew@wil.cx, linux-arch@vger.kernel.org, linuxppc64-dev@ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: Memory barriers and spin_unlock safety In-Reply-To: <5041.1141417027@warthog.cambridge.redhat.com> Message-ID: References: <32518.1141401780@warthog.cambridge.redhat.com> <1146.1141404346@warthog.cambridge.redhat.com> <5041.1141417027@warthog.cambridge.redhat.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 558 Lines: 16 On Fri, 3 Mar 2006, David Howells wrote: > > I suspect, then, that x86_64 should not have an SFENCE for smp_wmb(), and that > only io_wmb() should have that. Indeed. I think smp_wmb() should be a compiler fence only on x86(-64), ie just compile to a "barrier()" (and not even that on UP, of course). 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/