Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932127AbWIIDyQ (ORCPT ); Fri, 8 Sep 2006 23:54:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932129AbWIIDyQ (ORCPT ); Fri, 8 Sep 2006 23:54:16 -0400 Received: from smtp.osdl.org ([65.172.181.4]:34486 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S932127AbWIIDyP (ORCPT ); Fri, 8 Sep 2006 23:54:15 -0400 Date: Fri, 8 Sep 2006 20:54:08 -0700 (PDT) From: Linus Torvalds To: Paul Mackerras cc: linux-kernel@vger.kernel.org, benh@kernel.crashing.org, akpm@osdl.org, segher@kernel.crashing.org, davem@davemloft.net Subject: Re: Opinion on ordering of writel vs. stores to RAM In-Reply-To: <17666.11971.416250.857749@cargo.ozlabs.ibm.com> Message-ID: References: <17666.8433.533221.866510@cargo.ozlabs.ibm.com> <17666.11971.416250.857749@cargo.ozlabs.ibm.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: 768 Lines: 24 On Sat, 9 Sep 2006, Paul Mackerras wrote: > > > > although it's quite possible that (a) never makes any sense at all. > > Do you mean (b) never makes sense? Yes. > I suspect the best thing at this point is to move the sync in writeX() > before the store, as you suggest, and add an "eieio" before the load > in readX(). That does mean that we are then relying on driver writers > putting in the mmiowb() between a writeX() and a spin_unlock, but at > least that is documented. Yeah, that sounds reasonable. 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/