From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423341AbXDYR5L (ORCPT ); Wed, 25 Apr 2007 13:57:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1423358AbXDYR5L (ORCPT ); Wed, 25 Apr 2007 13:57:11 -0400 Received: from terminus.zytor.com ([192.83.249.54]:60323 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423354AbXDYR5J (ORCPT ); Wed, 25 Apr 2007 13:57:09 -0400 Message-ID: <462F9665.1090602@zytor.com> Date: Wed, 25 Apr 2007 10:56:53 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.0 (X11/20070419) MIME-Version: 1.0 To: "Eric W. Biederman" CC: Andrew Morton , Jeremy Fitzhardinge , Andi Kleen , Zachary Amsden , Linux Kernel Mailing List Subject: Re: [PATCH] i386: For debugging, make the initial page table setup less forgiving. References: <200704132149.l3DLnvUY012097@tazenda.hos.anvin.org> <20070425044813.f83dde4e.akpm@linux-foundation.org> <462F73A0.40003@zytor.com> In-Reply-To: X-Enigmail-Version: 0.95.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Eric W. Biederman wrote: >> This patch only affects the initial page tables, which should have been >> thrown out *way* long ago at this point. > > Yes. I noticed this was happening a few days ago. > I must not have mentioned it loudly enough. You mentioned the continued use of init_mm. This is *very* different. What we're seeing here is that ON PSE-CAPABLE HARDWARE, we continue to not just use the init_mm page directory, but the actual page *tables*, which should all have been replaced with PSE large pages to begin with. Reusing the initial page tables on non-PSE-capable hardware *sort of* makes sense, but his hardware should not fall in that category, I don't think? (Unless it's one of these machines that fall over if you map the bottom 4 MB with PSE pages?) -hpa