Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932415AbWBXSMq (ORCPT ); Fri, 24 Feb 2006 13:12:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932412AbWBXSMq (ORCPT ); Fri, 24 Feb 2006 13:12:46 -0500 Received: from smtp.osdl.org ([65.172.181.4]:17570 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S932263AbWBXSMp (ORCPT ); Fri, 24 Feb 2006 13:12:45 -0500 Date: Fri, 24 Feb 2006 10:11:25 -0800 (PST) From: Linus Torvalds To: Rene Herman cc: "Eric W. Biederman" , Arjan van de Ven , Andi Kleen , linux-kernel@vger.kernel.org, akpm@osdl.org, mingo@elte.hu Subject: Re: Patch to reorder functions in the vmlinux to a defined order In-Reply-To: <43FF48F2.70508@keyaccess.nl> Message-ID: References: <1140700758.4672.51.camel@laptopd505.fenrus.org> <1140707358.4672.67.camel@laptopd505.fenrus.org> <200602231700.36333.ak@suse.de> <1140713001.4672.73.camel@laptopd505.fenrus.org> <43FE0B9A.40209@keyaccess.nl> <43FE1764.6000300@keyaccess.nl> <43FE4B00.8080205@keyaccess.nl> <43FF26A8.9070600@keyaccess.nl> <43FF48F2.70508@keyaccess.nl> 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: 1160 Lines: 29 On Fri, 24 Feb 2006, Rene Herman wrote: > > The notion was that having a fixed virtual mapping of the kernel would allow > it to be loaded anywhere physically without needing to do actual address > fixups. Even that doesn't much help. You'd still need to fix up the actual addresses. Why? The virtual remapping is limited to 4MB chunks in order to be able to remap using large pages (2MB in PAE mode). At which point there is no advantage: you might as well just hardcode the default address to 4MB like my trivial one-liner did (with an option for EMBEDDED people to link it lower). So if the point is that we want to use the same binary for both machines with less than 4M and for bigger machines, you can't remap the kernel, unless you start using individual pages, at which point you've destroyed the biggest reason for doing this in the first place - since your TLB behaviour will suck. Linus - 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/