Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755282AbYHHGKx (ORCPT ); Fri, 8 Aug 2008 02:10:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754410AbYHHGKm (ORCPT ); Fri, 8 Aug 2008 02:10:42 -0400 Received: from gw.goop.org ([64.81.55.164]:53181 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752567AbYHHGKl (ORCPT ); Fri, 8 Aug 2008 02:10:41 -0400 Message-ID: <489BE351.5030206@goop.org> Date: Thu, 07 Aug 2008 23:10:25 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: "H. Peter Anvin" CC: Zachary Amsden , Alok Kataria , "torvalds@linux-foundation.org" , Ingo Molnar , the arch/x86 maintainers , LKML Subject: Re: [PATCH]Fix broken VMI in 2.6.27-rc.. References: <1218136365.23770.52.camel@alok-dev1> <489B6710.9000604@kernel.org> <1218144438.20178.336.camel@bodhitayantram.eng.vmware.com> <489B836A.3050209@goop.org> <489B84EF.6050009@kernel.org> <489B8948.6060003@goop.org> <489B8A68.10900@kernel.org> <489B8EF4.1030105@goop.org> <489B8FAD.4090904@kernel.org> In-Reply-To: <489B8FAD.4090904@kernel.org> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1337 Lines: 33 H. Peter Anvin wrote: > Jeremy Fitzhardinge wrote: >>> >>> The Linux kernel was never a paragon of perfection - it was never >>> meant to be. Just because a bit of cruft went unnoticed into the >>> kernel doesn't mean we shouldn't fix it. >> >> I don't really see what the issue is. >> >> Fixmaps are primarily used for things that need to be mapped early >> before we can allocate address space dynamically. They're >> predominantly used for boot-time init, and rarely on any >> performance-critical path. The only vaguely regular use a fixmap >> gets during runtime is poking at apics, and that's dominated by IO >> time, and kmap_atomic. Statically, there's only 100 references in >> the kernel. And it only affects 32-bit. >> >> Having fixmaps at link-time fixed addresses would be nice, I suppose, >> but hardly worth going to vast effort over. >> > > No, but it's hardly vast effort, either. Thinking about it, the fixmap really has to be as high as possible. If it were any lower, then it would either truncate the 1:1 mapping, or shadow some physical memory. J -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/