From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932289AbYBOHJM (ORCPT ); Fri, 15 Feb 2008 02:09:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762135AbYBOHI6 (ORCPT ); Fri, 15 Feb 2008 02:08:58 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:59071 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761662AbYBOHI5 (ORCPT ); Fri, 15 Feb 2008 02:08:57 -0500 Date: Fri, 15 Feb 2008 08:08:43 +0100 From: Ingo Molnar To: "Huang, Ying" Cc: Andi Kleen , torvalds@osdl.org, tglx@linutronix.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Fix left over EFI cache mapping problems Message-ID: <20080215070843.GA6975@elte.hu> References: <20080214131317.GA27769@basil.nowhere.org> <20080214161218.GA28152@elte.hu> <1203050886.30010.19.camel@caritas-dev.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1203050886.30010.19.camel@caritas-dev.intel.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Huang, Ying wrote: > On Thu, 2008-02-14 at 17:12 +0100, Ingo Molnar wrote: > > this is indeed a bug (we change the attributes for a larger area than > > needed), but your fix is unclean. Find below a cleaner solution. > > > > Ying, if you agree with this fix could you please test and ACK it before > > we push it to Linus? (this fix is also in the latest x86.git#mm) > > I think the patch following may be better, because it is possible that > the EFI_PAGE_SHIFT and PAGE_SHIFT are different. right now, EFI page size is 4096: include/linux/efi.h:#define EFI_PAGE_SHIFT 12 i doubt we'll ever change PAGE_SIZE on x86 - ia64's variable lowlevel pagesizes are not particularly useful IMO. I think we'll at most have some generic kernel feature that allows a larger PAGE_CACHE_SHIFT - but on the lowlevel MMU level we'll always stay at 4K. and i doubt EFI_PAGE_SHIFT would want to (ever) go away from 12 either. So perhaps, at least as far as arch/x86/kernel/efi*.c files go, it would be cleaner to just replace EFI_PAGE_SHIFT with PAGE_SHIFT and EFI_PAGE_SIZE with PAGE_SIZE? Ingo