Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S939655AbXFHXOm (ORCPT ); Fri, 8 Jun 2007 19:14:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754359AbXFHXOe (ORCPT ); Fri, 8 Jun 2007 19:14:34 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:40506 "EHLO ebiederm.dsl.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754172AbXFHXOe (ORCPT ); Fri, 8 Jun 2007 19:14:34 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Jesse Barnes Cc: Andi Kleen , linux-kernel@vger.kernel.org, Justin Piszcz Subject: Re: [PATCH] trim memory not covered by WB MTRRs References: <200706061229.24486.jesse.barnes@intel.com> <200706071030.15317.jesse.barnes@intel.com> Date: Fri, 08 Jun 2007 17:13:22 -0600 In-Reply-To: <200706071030.15317.jesse.barnes@intel.com> (Jesse Barnes's message of "Thu, 7 Jun 2007 10:30:14 -0700") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) 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 Content-Length: 1337 Lines: 34 Jesse Barnes writes: >> - Overlapping MTRRs. > > Overlapping should be ok, since that's usually intentional (e.g. one big > wb range with a portion of uc space due to another mtrr). I'm not say overlapping was a bug. I was saying that you don't handle overlapping mtrrs in figuring the last cached addresses. Therefore when a UC range overlaps a WB range we might thing the last page in the WB range is cached when it is not. >> - What happens if we have uncached memory lower down? > > Holes definitely aren't dealt with, but then we haven't seen any yet... > >> Except for performance problems I guess that case is relatively >> harmless. - Is it possible and worth it to amend the e820 map, so it >> shows the problem area as Reserved or otherwise not usable RAM? > > That would be useful, but only if we moved the check to a little > earlier, prior to the addition of the active ranges from the e820. > Might be a little nicer than adjusting end_pfn, but will ultimately > achieve the same thing... Yes, with perhaps a little more consistency. Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/