From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964795AbWDZSYQ (ORCPT ); Wed, 26 Apr 2006 14:24:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964797AbWDZSYQ (ORCPT ); Wed, 26 Apr 2006 14:24:16 -0400 Received: from mx2.suse.de ([195.135.220.15]:5781 "EHLO mx2.suse.de") by vger.kernel.org with ESMTP id S964795AbWDZSYP (ORCPT ); Wed, 26 Apr 2006 14:24:15 -0400 To: Martin Bligh Cc: Ken Harrenstien , linux-kernel Subject: Re: [kernel-reviewers] a small code review (2414483) Automated g4 rollback of changelist 2396062. References: <444F0729.2020407@google.com> <444F0A94.70100@google.com> <6599ad830604252300m27db3d20j39beafbe09788824@mail.google.com> <444F1218.6020601@google.com> <6599ad830604252334yd6d933w5386dccb4af4b971@mail.google.com> <444F9777.9090704@google.com> <444F989B.3040900@google.com> <444F9E2B.40704@google.com> <444FA2BB.2070908@google.com> <20060426173225.GB28519@google.com> <444FAFB6.4070303@google.com> From: Andi Kleen Date: 26 Apr 2006 20:24:13 +0200 In-Reply-To: <444FAFB6.4070303@google.com> Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Martin Bligh writes: > Tim Hockin wrote: > > On Wed, Apr 26, 2006 at 10:12:14AM -0700, Ken Harrenstien wrote: > > > >>That doesn't work because IIRC it only reports the amount of memory > >>the kernel has been told (eg via "mem=") to manage in a certain sense, > >>not how much is actually physically available. > >> > >>The I2 netboot kernel would really REALLY like some exported /proc > >>values that accurately report physical memory (if nothing else, the > >>number of DIMMs and their sizes). It has to figure this out in order > >>to install the proper kernel with proper LILO command-line args. > > The kernel can't really know how much memory is in the system without > > getting chipset-specific. > > MTRR is a good way to hazard a guess, and will probably be right, > > but as > > you indicated, BIOS vendors have historically been REALLY bad about > > MTRRs. Better now, but bad a few years ago. > > SMBIOS (on our boards) *does* accurately report the number of DIMMS > > and > > their sizes (and more!). But it only works on Google BIOS. Actually quite a lot of SMBIOS report DIMMs more or less correct. It works even on my laptop. I implemented support for it in the latest mcelog (--dmi). Not all and a few big names screw it up (in particular the mappings from address range to interleave set). But overall it looks surprisingly good so far. -Andi