From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932180AbZAPL4l (ORCPT ); Fri, 16 Jan 2009 06:56:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758722AbZAPL4c (ORCPT ); Fri, 16 Jan 2009 06:56:32 -0500 Received: from vpn.id2.novell.com ([195.33.99.129]:50144 "EHLO vpn.id2.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757957AbZAPL4b convert rfc822-to-8bit (ORCPT ); Fri, 16 Jan 2009 06:56:31 -0500 Message-Id: <49708423.76E4.0078.0@novell.com> X-Mailer: Novell GroupWise Internet Agent 8.0.0 Date: Fri, 16 Jan 2009 11:57:07 +0000 From: "Jan Beulich" To: "Ingo Molnar" , "H. Peter Anvin" Cc: , Subject: Re: [PATCH] x86: simplify HIGHMEM-related Kconfig entries References: <496DE927.76E4.0078.0@novell.com> <496E3F7D.2060908@zytor.com> <496F0796.76E4.0078.0@novell.com> <20090115085728.GA28607@elte.hu> <496F6DFC.90006@zytor.com> In-Reply-To: <496F6DFC.90006@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> "H. Peter Anvin" 15.01.09 18:10 >>> >Ingo Molnar wrote: >>>> >>>> No highmem - No highmem, no PAE >>>> HIGHMEM4G - Highmem, no PAE >>>> HIGHMEM64G - Highmem, PAE >>>> >>>> So X86_PAE and HIGHMEM4G is a bit of a contradiction. I haven't looked >>>> at the logic in detail, or remember offhand if there have been any >>>> weakening of the definitions above; e.g. someone could have implemented >>>> a way to do PAE without highmem, to get access to the NX bits. >>> Exactly - .23 made PAE an independently selectable option (in >>> particular, the no-highmem+PAE combination is now valid), but I can't >>> see why it added the !HIGHMEM4G dependency. >> >> There's no deep reason, it just has never really been tested that way. I >> think we should try it. > >If so, what would be the difference between HIGHMEM4G and HIGHMEM64G in >that case at all? For example being able to select the DMADEVICES config option. Jan