Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751456AbWIKNTj (ORCPT ); Mon, 11 Sep 2006 09:19:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751477AbWIKNTj (ORCPT ); Mon, 11 Sep 2006 09:19:39 -0400 Received: from jaguar.mkp.net ([192.139.46.146]:23493 "EHLO jaguar.mkp.net") by vger.kernel.org with ESMTP id S1751456AbWIKNTi (ORCPT ); Mon, 11 Sep 2006 09:19:38 -0400 To: Benjamin Herrenschmidt Cc: Alan Cox , Jesse Barnes , David Miller , jeff@garzik.org, paulus@samba.org, torvalds@osdl.org, linux-kernel@vger.kernel.org, akpm@osdl.org, segher@kernel.crashing.org, jeremy@sgi.com Subject: Re: Opinion on ordering of writel vs. stores to RAM References: <17666.11971.416250.857749@cargo.ozlabs.ibm.com> <45028F87.7040603@garzik.org> <20060909.030854.78720744.davem@davemloft.net> <200609101018.06930.jbarnes@virtuousgeek.org> <1157916919.23085.24.camel@localhost.localdomain> <1157923513.31071.256.camel@localhost.localdomain> <1157926993.23085.29.camel@localhost.localdomain> <1157926708.31071.259.camel@localhost.localdomain> From: Jes Sorensen Date: 11 Sep 2006 09:19:36 -0400 In-Reply-To: <1157926708.31071.259.camel@localhost.localdomain> Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.4 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: 1220 Lines: 23 >>>>> "Ben" == Benjamin Herrenschmidt writes: Ben> On Sun, 2006-09-10 at 23:23 +0100, Alan Cox wrote: >> Ar Llu, 2006-09-11 am 07:25 +1000, ysgrifennodd Benjamin >> Herrenschmidt: > I'm copying that from a private discussion I >> had. Please let me know if > you have comments. This proposal >> includes some questions too so please > answer :) >> >> Looks sane and Linus seems to like mmiowb. Only other question: >> what are the guarantees of memcpy_to/fromio. Does it access the >> memory in ordered fashion or not, does it guarantee only ordering >> at the end of the copy or during it ? Ben> Well, Linus is also ok with writel not ordering memory an IO Ben> accesses :) Though he also mentioned that if we go that route Ben> (which is what we have now in fact), we take the burden of having Ben> to test and fix drivers who don't get it... We have to do this on SN2 anyway, so this way we can benefit from each other's work :) Cheers, Jes - 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/