Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752980AbXFLVar (ORCPT ); Tue, 12 Jun 2007 17:30:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750747AbXFLVak (ORCPT ); Tue, 12 Jun 2007 17:30:40 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:53651 "EHLO amd.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750745AbXFLVak (ORCPT ); Tue, 12 Jun 2007 17:30:40 -0400 Date: Tue, 12 Jun 2007 23:30:20 +0200 From: Pavel Machek To: Jesse Barnes Cc: Andi Kleen , linux-kernel@vger.kernel.org, Justin Piszcz , "Eric W. Biederman" Subject: Re: [PATCH] trim memory not covered by WB MTRRs Message-ID: <20070612213020.GA13747@elf.ucw.cz> References: <200706071530.51552.jesse.barnes@intel.com> <20070612145007.GA5986@ucw.cz> <200706120829.21465.jesse.barnes@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200706120829.21465.jesse.barnes@intel.com> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1660 Lines: 38 Hi! > > > On some machines, buggy BIOSes don't properly setup WB MTRRs to > > > cover all available RAM, meaning the last few megs (or even gigs) > > > of memory will be marked uncached. Since Linux tends to allocate > > > from high memory addresses first, this causes the machine to be > > > unusably slow as soon as the kernel starts really using memory > > > (i.e. right around init time). > > > > > > + if ((highest_addr >> PAGE_SHIFT) != end_pfn) { > > > + printk(KERN_WARNING "***************\n"); > > > + printk(KERN_WARNING "**** WARNING: likely BIOS bug\n"); > > > + printk(KERN_WARNING "**** MTRRs don't cover all of " > > > + "memory, trimmed %ld pages\n", end_pfn - > > > + (highest_addr >> PAGE_SHIFT)); > > > + printk(KERN_WARNING "***************\n"); > > > + end_pfn = highest_addr >> PAGE_SHIFT; > > > > Missing 4K of memory is not worth 4K of junk in syslog per boot. Can > > you drop the stars and stop shouting? > > How missing about 1G of memory? We already discussed this, and Andi and > Venki felt that either a panic or a really obnoxious message was the > way to go... Just use panic, then. Pavel, who still thinks anyone missing 1GB of ram will not miss friendly notice in dmesg, even if it goes without 20 stars. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - 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/