From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750991AbWAYDO6 (ORCPT ); Tue, 24 Jan 2006 22:14:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750992AbWAYDO6 (ORCPT ); Tue, 24 Jan 2006 22:14:58 -0500 Received: from teetot.devrandom.net ([66.35.250.243]:64645 "EHLO teetot.devrandom.net") by vger.kernel.org with ESMTP id S1750990AbWAYDO6 (ORCPT ); Tue, 24 Jan 2006 22:14:58 -0500 Date: Tue, 24 Jan 2006 19:17:38 -0800 From: thockin@hockin.org To: Prakash Punnoor Cc: linux-kernel@vger.kernel.org Subject: Re: AMD64, 4GB, mttr questions Message-ID: <20060125031738.GA8656@hockin.org> References: <200601241433.50625.prakash@punnoor.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200601241433.50625.prakash@punnoor.de> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 24, 2006 at 02:33:46PM +0100, Prakash Punnoor wrote: > I have a machine with 4GB RAM, an Athlon64 X2 and following mttr entries: > > reg00: base=0x00000000 ( 0MB), size=4096MB: write-back, count=1 > reg01: base=0x100000000 (4096MB), size=2048MB: write-back, count=1 > reg02: base=0x80000000 (2048MB), size=2048MB: uncachable, count=1 > > First of all, why is there an uncachable region? Is it the upper half of > memory? Or is this just a hole and the remaining 2GB are seated at > 0x100000000 ? That's the IO hole between 2 and 4 GB. Your setup looks fine to me. It's perfectly valid to have an uncacheable region overlap a write-back region.