Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932661AbYAaQiW (ORCPT ); Thu, 31 Jan 2008 11:38:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758631AbYAaQiO (ORCPT ); Thu, 31 Jan 2008 11:38:14 -0500 Received: from mx1.suse.de ([195.135.220.2]:38827 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754538AbYAaQiN (ORCPT ); Thu, 31 Jan 2008 11:38:13 -0500 Date: Thu, 31 Jan 2008 17:38:12 +0100 From: Andi Kleen To: Thomas Gleixner Cc: Andi Kleen , mingo@elte.hu, linux-kernel@vger.kernel.org Subject: Re: [PATCH] [9/9] GBPAGES: Do kernel direct mapping at boot using GB pages Message-ID: <20080131163812.GE25989@bingen.suse.de> References: <20080129606.610336873@suse.de> <20080129050637.BD7441B416E@basil.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1760 Lines: 48 On Thu, Jan 31, 2008 at 05:17:41PM +0100, Thomas Gleixner wrote: > On Tue, 29 Jan 2008, Andi Kleen wrote: > > > > +static unsigned long direct_entry(unsigned long paddr) > > Please use a more sensible function name. This one has no association > with the functionality at all. Can you suggest one? I honestly cannot think of a better one. Its's a "entry" in the "direct" mapping. > > + if (direct_gbpages >= 0 && cpu_has_gbpages) { > > + printk(KERN_INFO "Using GB pages for direct mapping\n"); > > + direct_gbpages = 1; > > + } else > > + direct_gbpages = 0; > > +} > > Please use simple boolean logic. gbpages are either enabled or disabled. It's a fairly standard widely used idiom for command line options because it allows default and forcing. e.g. there can be cases when the kernel disables it, but then it makes sense for the command line option to override it. There is already one case in the kernel that disables it. > > * prefetches from the CPU leading to inconsistent cache lines. > > @@ -467,6 +511,8 @@ __clear_kernel_mapping(unsigned long add > > continue; > > > > pud = pud_offset(pgd, address); > > + if (pud_large(*pud)) > > + split_gb_page(pud, __pa(address)); > > if (pud_none(*pud)) > > continue; > > As I said before, this needs to use CPA and not implement another variant. Ok, I can switch GART over to CPA, but that will make the patch much more intrusive and a little riskier. Is that ok for you and will it be still considered .25 candidate? -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/