From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 29 Jan 2003 10:56:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 29 Jan 2003 10:56:36 -0500 Received: from mail.ithnet.com ([217.64.64.8]:3091 "HELO heather.ithnet.com") by vger.kernel.org with SMTP id ; Wed, 29 Jan 2003 10:56:35 -0500 Date: Wed, 29 Jan 2003 17:05:54 +0100 From: Stephan von Krawczynski To: Mark Hahn Cc: linux-kernel Subject: Re: no more MTRRs available ? Message-Id: <20030129170554.08dc6393.skraw@ithnet.com> In-Reply-To: References: <20030129164552.182e0cb8.skraw@ithnet.com> Organization: ith Kommunikationstechnik GmbH X-Mailer: Sylpheed version 0.8.9 (GTK+ 1.2.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 29 Jan 2003 10:51:03 -0500 (EST) Mark Hahn wrote: > > > > what exactly does > > > > > > > > mtrr: no more MTRRs available > > > > mtrr: no more MTRRs available > > > > > > > > during boot mean? What can I do against this? This comes up while > > > > booting a system with 6GB and P-III 1.4 GHz (Serverworks chipset). > > > > Kernel is 2.4.20. > > > > > > you need to look at /proc/mtrr. > > > > Thanks for your hint, but what does this tell me? > > that your bios is stupid, I think. mtrr's handle areas that are > powers of two in size (and >= 1M, I think). the problem here is that > the bios is trying to represent 4G of write-back ram and a 16M of > uncachable IO area (AGP aperture, I'm guessing). the correct way > to do this is a single 4G mtrr with an overlapping 16M one. Ah, I see. So getting the above two messages would simply mean that there is no table space left to add yet another two entries kernel gets from bios? > do you have >4G ram? that would explain the latter two. Yes, this box has 6GB. > note that you can fairly freely add/delete mtrr's from userspace. > as long as you do it infrequently, I don't see why there would be > any risk or performance problem. So the conclusion is that it does not look nice currently, but does not do any harm (performance loss) either. I can live with that. Thanks for your comments. > > # cat /proc/mtrr > > reg00: base=0x00000000 ( 0MB), size=2048MB: write-back, count=1 > > reg01: base=0x80000000 (2048MB), size=1024MB: write-back, count=1 > > reg02: base=0xc0000000 (3072MB), size= 512MB: write-back, count=1 > > reg03: base=0xe0000000 (3584MB), size= 256MB: write-back, count=1 > > reg04: base=0xf0000000 (3840MB), size= 128MB: write-back, count=1 > > reg05: base=0xf7000000 (3952MB), size= 16MB: uncachable, count=1 > > reg06: base=0x100000000 (4096MB), size=4096MB: write-back, count=1 > > reg07: base=0x200000000 (8192MB), size=8192MB: write-back, count=1 -- Regards, Stephan