From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262831AbUBZSCf (ORCPT ); Thu, 26 Feb 2004 13:02:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262845AbUBZSCf (ORCPT ); Thu, 26 Feb 2004 13:02:35 -0500 Received: from terminus.zytor.com ([63.209.29.3]:49896 "EHLO terminus.zytor.com") by vger.kernel.org with ESMTP id S262831AbUBZSCd (ORCPT ); Thu, 26 Feb 2004 13:02:33 -0500 Message-ID: <403E34B1.3030608@zytor.com> Date: Thu, 26 Feb 2004 10:02:25 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6b) Gecko/20040105 X-Accept-Language: en, sv, es, fr MIME-Version: 1.0 To: "Eric W. Biederman" CC: linux-kernel Subject: Re: [PATCH] Early memory patch, +accounting References: <403ADCDD.8080206@zytor.com> <403CEE33.3020601@zytor.com> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Eric W. Biederman wrote: > > I intend to export _end into setup.S so a bootloader can > tell what memory the kernel will attempt to use before looking at > the e820 map, the kernel command line, and the initrd location. > After that the kernel can properly dynamically allocate things. > You're confusing "may" with "will". This is the fundamental problem with this approach. > Exporting _end will allow two things. > 1) On systems with a 15M-16M I/O hole the bootloader can check to see > if a big kernel will attempt to use memory in that region. > > 2) On small memory systems it will let the bootloader make a good > estimate to see if everything will fit into memory. No, it won't, because it still has no idea whatsoever how much dynamically allocated memory it needs during boot. -hpa