Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759262AbYAJJzb (ORCPT ); Thu, 10 Jan 2008 04:55:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758812AbYAJJzE (ORCPT ); Thu, 10 Jan 2008 04:55:04 -0500 Received: from mx2.suse.de ([195.135.220.15]:56815 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758787AbYAJJzD (ORCPT ); Thu, 10 Jan 2008 04:55:03 -0500 Date: Thu, 10 Jan 2008 10:55:01 +0100 From: Andi Kleen To: Dave Airlie Cc: Ingo Molnar , Andi Kleen , linux-kernel@vger.kernel.org, Thomas Gleixner , "H. Peter Anvin" , Venki Pallipadi , suresh.b.siddha@intel.com, Arjan van de Ven , Dave Jones Subject: Re: CPA patchset Message-ID: <20080110095501.GL25945@bingen.suse.de> References: <20080103424.989432000@suse.de> <20080110093126.GA360@elte.hu> <21d7e9970801100144x63b02e1bga548acd3c5bed441@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <21d7e9970801100144x63b02e1bga548acd3c5bed441@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1389 Lines: 33 On Thu, Jan 10, 2008 at 07:44:03PM +1000, Dave Airlie wrote: > > > > finally managed to get the time to review your CPA patchset, and i > > fundamentally agree with most of the detail changes done in it. But here > > are a few structural high-level observations: > > > > - firstly, there's no rationale given. So we'll change ioremap()/etc. > > from doing a cflush-range instruction instead of a WBINVD. But why? > > WBINVD isnt particular fast (takes a few msecs), but why is that a > > problem? Drivers dont do high-frequency ioremap-ing. It's typically > > only done at driver/device startup and that's it. Whether module load > > time takes 1254 msecs instead of 1250 msecs is no big deal. > > read graphics drivers, even though I think we may avoid the whole path You mean avoid change_page_attr() ? > if we can and end up doing some of this in the drivers > when they know more about the situation so can avoid safeties.. Please explain, but it sounds very dubious. > but I still see this being used in AGP a fair bit at some point on > some drivers.. Well GARTs and those are widely used even without AGP busses. -Andi -- 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/