From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754400AbZBEVvS (ORCPT ); Thu, 5 Feb 2009 16:51:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752098AbZBEVvE (ORCPT ); Thu, 5 Feb 2009 16:51:04 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:38345 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751804AbZBEVvC (ORCPT ); Thu, 5 Feb 2009 16:51:02 -0500 Date: Thu, 5 Feb 2009 22:50:50 +0100 From: Ingo Molnar To: Jeremy Fitzhardinge Cc: Hugh Dickins , William Lee Irwin III , Linux Kernel Mailing List , Linux Memory Management List Subject: Re: pud_bad vs pud_bad Message-ID: <20090205215050.GB28097@elte.hu> References: <498B2EBC.60700@goop.org> <20090205184355.GF5661@elte.hu> <498B35F9.601@goop.org> <20090205191017.GF20470@elte.hu> <498B4F1F.5070306@goop.org> <498B54A0.7040005@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <498B54A0.7040005@goop.org> User-Agent: Mutt/1.5.18 (2008-05-17) 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 * Jeremy Fitzhardinge wrote: >> I sincerely hope 0! I shed no tears at losing support for NUMAQ, but why >> should we be forced to double all the 32-bit ptes? You want us all to be >> using NX? Or you just want to cut your test/edit matrix - that I can >> well understand! > > Yes, that's the gist of it. We could simplify things by having only one > pte format and only have to parameterise with 3/4 level pagetables. We'd > lose support for non-PAE cpus, including the first Pentium M (which is > probably still in fairly wide use, unfortunately). We'd also lose a fair bit of performance (not to mention the pagetable footprint doubling that Hugh already mentioned) on 32-bit PAE capable systems that dont actually have RAM above 4G physical. Bad idea really ... Ingo