Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753327AbXIHKWp (ORCPT ); Sat, 8 Sep 2007 06:22:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751928AbXIHKWi (ORCPT ); Sat, 8 Sep 2007 06:22:38 -0400 Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:39577 "EHLO the-village.bc.nu" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751867AbXIHKWh (ORCPT ); Sat, 8 Sep 2007 06:22:37 -0400 Date: Sat, 8 Sep 2007 11:30:56 +0100 From: Alan Cox To: Nick Piggin Cc: Jesse Barnes , linux-kernel@vger.kernel.org Subject: Re: Intel Memory Ordering White Paper Message-ID: <20070908113056.66fc97b7@the-village.bc.nu> In-Reply-To: <200709081854.57549.nickpiggin@yahoo.com.au> References: <200709071526.51169.jesse.barnes@intel.com> <200709081854.57549.nickpiggin@yahoo.com.au> X-Mailer: Claws Mail 2.10.0 (GTK+ 2.10.14; i386-redhat-linux-gnu) Organization: Red Hat UK Cyf., Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, Y Deyrnas Gyfunol. Cofrestrwyd yng Nghymru a Lloegr o'r rhif cofrestru 3798903 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1013 Lines: 26 On Sat, 8 Sep 2007 18:54:57 +1000 Nick Piggin wrote: > On Saturday 08 September 2007 08:26, Jesse Barnes wrote: > > FYI, we just released a new white paper describing memory ordering for > > Intel processors: > > http://developer.intel.com/products/processor/manuals/index.htm > > > > Should help answer some questions about some of the ordering primitives > > we use on i386 and x86_64. > > So, can we finally noop smp_rmb and smp_wmb on x86? Nakked-by: Alan Cox You can only no-op it on 64bit Intel processors. On 32bit it needs to be conditional on whether your processor family (or back compat for it) as the Pentium Pro has some serious store ordering errata (hence the way it needs lock decb for spin_unlock) Alan - 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/