From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757160AbZEHE7k (ORCPT ); Fri, 8 May 2009 00:59:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751669AbZEHE7b (ORCPT ); Fri, 8 May 2009 00:59:31 -0400 Received: from terminus.zytor.com ([198.137.202.10]:54205 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751060AbZEHE7a (ORCPT ); Fri, 8 May 2009 00:59:30 -0400 Message-ID: <4A03BC1A.9060605@zytor.com> Date: Thu, 07 May 2009 21:59:06 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Jan Beulich CC: mingo@elte.hu, tglx@linutronix.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86-64: improve e820_search_gap() References: <4A0199B8.76EA.0078.0@novell.com> In-Reply-To: <4A0199B8.76EA.0078.0@novell.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jan Beulich wrote: > Impact: bug fix > > Blindly putting the gap close after max_pfn is in conflict with that > same memory range potentially being used by hotplugged memory. > > Also, make the function static to ensure there are no other users that > could depend on the previous behavior regarding the way start_addr gets > specified. > > Signed-off-by: Jan Beulich > So blindly locate it somewhere else? How is that inherently better? Wouldn't a machine with hotplug memory (which doesn't bother advertising that fact so we can reserve the address space) be just as likely to use a sparse memory space, since one can hardly expect the hardware to pack the space (packing in hardware is why PCs generally have a mostly-contiguous RAM space) when the memory is hotplugged? I think I'm missing something fundamental... -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.