From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759191AbZBET1O (ORCPT ); Thu, 5 Feb 2009 14:27:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752223AbZBET06 (ORCPT ); Thu, 5 Feb 2009 14:26:58 -0500 Received: from gw.goop.org ([64.81.55.164]:53992 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752494AbZBET06 (ORCPT ); Thu, 5 Feb 2009 14:26:58 -0500 Message-ID: <498B3D80.1010206@goop.org> Date: Thu, 05 Feb 2009 11:26:56 -0800 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.19 (X11/20090105) MIME-Version: 1.0 To: Ingo Molnar CC: William Lee Irwin III , Linux Kernel Mailing List , Linux Memory Management List Subject: Re: pud_bad vs pud_bad References: <498B2EBC.60700@goop.org> <20090205184355.GF5661@elte.hu> <498B35F9.601@goop.org> <20090205191017.GF20470@elte.hu> In-Reply-To: <20090205191017.GF20470@elte.hu> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar wrote: > But the 32-bit check does the exact same thing but via a single binary > operation: it checks whether any bits outside of those bits are zero - just > via a simpler test that compiles to more compact code. > > So i'd go with the 32-bit version. (unless there are some sign-extension > complications i'm missing - but i think we got rid of those already.) OK, fair enough. I wouldn't be surprised if gcc does that transform anyway, but we may as well be consistent about it. J