From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759871AbZANCWc (ORCPT ); Tue, 13 Jan 2009 21:22:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751800AbZANCWW (ORCPT ); Tue, 13 Jan 2009 21:22:22 -0500 Received: from sj-iport-4.cisco.com ([171.68.10.86]:17168 "EHLO sj-iport-4.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753322AbZANCWV (ORCPT ); Tue, 13 Jan 2009 21:22:21 -0500 X-IronPort-AV: E=Sophos;i="4.37,261,1231113600"; d="scan'208";a="27999938" From: Roland Dreier To: "James Kirin" Cc: linux-kernel@vger.kernel.org Subject: Re: memory beyond4GB invisible to the system even though CONFIG_HIGHMEM64G=y References: X-Message-Flag: Warning: May contain useful information Date: Tue, 13 Jan 2009 18:22:19 -0800 In-Reply-To: (James Kirin's message of "Wed, 14 Jan 2009 01:46:33 +0000") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.60 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-OriginalArrivalTime: 14 Jan 2009 02:22:20.0324 (UTC) FILETIME=[ED740640:01C975EE] Authentication-Results: sj-dkim-4; header.From=rdreier@cisco.com; dkim=pass ( sig from cisco.com/sjdkim4002 verified; ); Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > I am running kernel 2.6.28 on a computer with 8GB RAM. The BIOS > detects all 8GB, yet > > jk@as12:~$ free > total used free shared buffers cached > Mem: 3622504 799696 2822808 0 90936 369604 > -/+ buffers/cache: 339156 3283348 > Swap: 6867776 0 6867776 The message in your kernel log: [ 0.000000] WARNING: BIOS bug: CPU MTRRs don't cover all of memory, losing 4096MB of RAM. [ 0.000000] ------------[ cut here ]------------ [ 0.000000] WARNING: at arch/x86/kernel/cpu/mtrr/main.c:1662 mtrr_trim_uncached_memory+0x283/0x2a4() is a clue. You might want to look for a BIOS update for your motherboard. - R.