Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755470AbYFYXGd (ORCPT ); Wed, 25 Jun 2008 19:06:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752275AbYFYXGZ (ORCPT ); Wed, 25 Jun 2008 19:06:25 -0400 Received: from gw.goop.org ([64.81.55.164]:35459 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751768AbYFYXGY (ORCPT ); Wed, 25 Jun 2008 19:06:24 -0400 Message-ID: <4862CF57.1010106@goop.org> Date: Wed, 25 Jun 2008 16:05:59 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Arjan van de Ven CC: Ingo Molnar , LKML , x86@kernel.org, xen-devel , Stephen Tweedie , Eduardo Habkost , Mark McLoughlin Subject: Re: [PATCH 03 of 36] x86: add memory barriers to wrmsr References: <93c7057b1f4acae501b2.1214367539@localhost> <20080624214441.13202f12@infradead.org> <4862B3E9.50601@goop.org> <20080625153136.2b3b6737@infradead.org> In-Reply-To: <20080625153136.2b3b6737@infradead.org> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1100 Lines: 42 Arjan van de Ven wrote: > On Wed, 25 Jun 2008 14:08:57 -0700 > Jeremy Fitzhardinge wrote: > > >> Arjan van de Ven wrote: >> >>> it's more readable for several of these cases to stick a barrier(); >>> in front and after it to be honest; that makes it more explicit that >>> these are deliberate compiler barriers rather than "actual" memory >>> access... >>> >>> >>> >> I suppose, though I would be inclined to put the barriers in the >> wrmsr macro itself to act as documentation. >> > > > yeah I meant like this: > > static inline void native_write_msr(unsigned int msr, > unsigned low, unsigned high) > { > barrier(); > asm volatile("wrmsr" : : "c" (msr), "a"(low), "d" (high)); > barrier(); > } > > or in the same in the thing that calls this. > > OK, we're in vehement agreement then. J -- 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/