From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031706AbXEANci (ORCPT ); Tue, 1 May 2007 09:32:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1031705AbXEANci (ORCPT ); Tue, 1 May 2007 09:32:38 -0400 Received: from rtr.ca ([64.26.128.89]:3269 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031704AbXEANcg (ORCPT ); Tue, 1 May 2007 09:32:36 -0400 Message-ID: <46374171.1050009@rtr.ca> Date: Tue, 01 May 2007 09:32:33 -0400 From: Mark Lord User-Agent: Thunderbird 2.0.0.0 (X11/20070326) MIME-Version: 1.0 To: William Lee Irwin III Cc: Andi Kleen , ebiederm@xmission.com, patches@x86-64.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] [30/30] x86_64: Add missing !X86_PAE dependincy to the 2G/2G split. References: <20070501557.815359000@suse.de> <20070501035829.1C93D13CAF@wotan.suse.de> <20070501043735.GR31925@holomorphy.com> In-Reply-To: <20070501043735.GR31925@holomorphy.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org William Lee Irwin III wrote: > On Tue, May 01, 2007 at 05:58:29AM +0200, Andi Kleen wrote: >> From: ebiederm@xmission.com >> When in PAE mode we require that the user kernel divide to be >> on a 1G boundary. The 2G/2G split does not have that property >> so require !X86_PAE >> Signed-off-by: Eric W. Biederman >> --- >> arch/i386/Kconfig | 1 + >> 1 files changed, 1 insertions(+), 0 deletions(-) > > What on earth? > > config PAGE_OFFSET > hex > default 0xB0000000 if VMSPLIT_3G_OPT > default 0x78000000 if VMSPLIT_2G > default 0x40000000 if VMSPLIT_1G > default 0xC0000000 > > This appears to have been introduced by: > commit 975b3d3d5b983eb60706d35f0d24cd19f6badabf > Author: Mark Lord > Date: Wed Feb 1 03:06:11 2006 -0800 > [PATCH] VMSPLIT config options > > There's some sort of insanity going on here. Since when is 0x78000000 > a 2GB/2GB split? Mark, dare I ask what you were thinking? That should > be VMSPLIT_2G_OPT for 2GB laptops analogously to VMSPLIT_3G_OPT, if > nothing else, as it's certainly not 2GB/2GB. You need to go search the archives and read the *extensive* thread on this from when it was introduced. Lots of high profile kernel developers were in on this one. The idea is really simple: eliminate the need for HIGHMEM on common machines. And yes, VMSPLIT_2G really means VMSPLIT_2G_OPT, in the same way as the (added last) VMSPLIT_3G_OPT flag. Cheers