From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754968AbYHVFzJ (ORCPT ); Fri, 22 Aug 2008 01:55:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752675AbYHVFyy (ORCPT ); Fri, 22 Aug 2008 01:54:54 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:54650 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752674AbYHVFyx (ORCPT ); Fri, 22 Aug 2008 01:54:53 -0400 Date: Fri, 22 Aug 2008 07:54:37 +0200 From: Ingo Molnar To: Jan Beulich Cc: tglx@linutronix.de, hpa@zytor.com, linux-kernel@vger.kernel.org, Yinghai Lu Subject: Re: [PATCH] x86-64: fix 1:1 mapping init (hotplug case) Message-ID: <20080822055437.GA14110@elte.hu> References: <48AD895A.76E4.0078.0@novell.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <48AD895A.76E4.0078.0@novell.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jan Beulich wrote: > While I don't have a hotplug capable system at hand, I think two issues need > fixing: > - pud_phys (in kernel_physical_ampping_init()) would remain uninitialized in > the after_bootmem case > - the locking done just around phys_pmd_{init,update}() would leave out pgd > updates, and it was needlessly covering code portions that do allocations > (perhaps using a more friendly gfp value in alloc_low_page() would then be > possible) applied to tip/x86/urgent. Some sort of memory hotplug simulation debug code would be nice ... [bonus points for making it run automatically during bootup, as part of the kernel init code] it wouldnt even be all that expensive to test: we'd parts of RAM as to-be-hotplugged, we'd boot in and then hot-add those ranges. It's not full unrestricted RAM in the classic sense, but for most practical purposes it would be that. Ingo