Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751417AbWCGRlA (ORCPT ); Tue, 7 Mar 2006 12:41:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751414AbWCGRlA (ORCPT ); Tue, 7 Mar 2006 12:41:00 -0500 Received: from palinux.external.hp.com ([192.25.206.14]:21936 "EHLO palinux.hppa") by vger.kernel.org with ESMTP id S1751417AbWCGRk7 (ORCPT ); Tue, 7 Mar 2006 12:40:59 -0500 Date: Tue, 7 Mar 2006 10:40:57 -0700 From: Matthew Wilcox To: David Howells Cc: Linus Torvalds , akpm@osdl.org, ak@suse.de, mingo@redhat.com, jblunck@suse.de, bcrl@linux.intel.com, linux-arch@vger.kernel.org, linuxppc64-dev@ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: Memory barriers and spin_unlock safety Message-ID: <20060307174057.GD7301@parisc-linux.org> References: <5041.1141417027@warthog.cambridge.redhat.com> <32518.1141401780@warthog.cambridge.redhat.com> <1146.1141404346@warthog.cambridge.redhat.com> <31420.1141753019@warthog.cambridge.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <31420.1141753019@warthog.cambridge.redhat.com> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 695 Lines: 20 On Tue, Mar 07, 2006 at 05:36:59PM +0000, David Howells wrote: > 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. > > Hmmm... We don't actually have io_wmb()... Should the following be added to > all archs? > > io_mb() > io_rmb() > io_wmb() it's spelled mmiowb(), and reads from IO space are synchronous, so don't need barriers. - 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/