From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758330AbZEHUtD (ORCPT ); Fri, 8 May 2009 16:49:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753910AbZEHUsw (ORCPT ); Fri, 8 May 2009 16:48:52 -0400 Received: from one.firstfloor.org ([213.235.205.2]:36395 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753520AbZEHUsv (ORCPT ); Fri, 8 May 2009 16:48:51 -0400 Date: Fri, 8 May 2009 22:53:47 +0200 From: Andi Kleen To: "H. Peter Anvin" Cc: Andi Kleen , Jan Beulich , mingo@elte.hu, tglx@linutronix.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86-64: improve e820_search_gap() Message-ID: <20090508205347.GC23223@one.firstfloor.org> References: <4A0199B8.76EA.0078.0@novell.com> <4A03BC1A.9060605@zytor.com> <4A03F016.76EA.0078.0@novell.com> <874ovvo0wo.fsf@basil.nowhere.org> <4A0492EA.6080403@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A0492EA.6080403@zytor.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 08, 2009 at 01:15:38PM -0700, H. Peter Anvin wrote: > Andi Kleen wrote: > >"Jan Beulich" writes: > >>Why blindly? Aren't hotpluggable memory ranges supposed to be reserved > >>in the E820 map? > > > >They are supposed to be reserved in SRAT, but not in e820. > > Ah, okay. Perhaps we should fold this information into our internal > "e820" map? If so I guess the question is how soon we can do that. You could do that or just query SRAT too, but ... The problem is really that there are still systems which have hidden holes which are not reserved anywhere. When I last hacked on the gap algorithm it triggered subtle bugs. So this will never be fully reliable. -Andi -- ak@linux.intel.com -- Speaking for myself only.