From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261575AbULBHLs (ORCPT ); Thu, 2 Dec 2004 02:11:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261571AbULBHLs (ORCPT ); Thu, 2 Dec 2004 02:11:48 -0500 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:31141 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S261570AbULBHLm (ORCPT ); Thu, 2 Dec 2004 02:11:42 -0500 Message-ID: <41AEC021.8040000@pobox.com> Date: Thu, 02 Dec 2004 02:11:29 -0500 From: Jeff Garzik User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.3) Gecko/20040922 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Benjamin Herrenschmidt CC: Andrew Morton , Linus Torvalds , Linux Kernel list , list linux-ide Subject: Re: page fault scalability patch V12 [0/7]: Overview and performance tests References: <41AEB44D.2040805@pobox.com> <20041201223441.3820fbc0.akpm@osdl.org> <41AEBD95.7030804@pobox.com> <1101971149.5593.64.camel@gaston> In-Reply-To: <1101971149.5593.64.camel@gaston> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Benjamin Herrenschmidt wrote: > They may not end up in order if they are stores (the stores to the > taskfile may be out of order vs; the loads/stores to/from the data > register) unless you have a spinlock protecting both or a full sync (on > ppc), but then, I don't know the ordering things on x86_64. This could > certainly be a problem on ppc & ppc64 too. Is synchronization beyond in[bwl] needed, do you think? This specific problem is only on Intel ICHx AFAICS, which is PIO not MMIO and x86-only. I presumed insw() by its very nature already has synchronization, but perhaps not... Jeff