From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263029AbTEGJfX (ORCPT ); Wed, 7 May 2003 05:35:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263047AbTEGJfX (ORCPT ); Wed, 7 May 2003 05:35:23 -0400 Received: from zero.aec.at ([193.170.194.10]:21775 "EHLO zero.aec.at") by vger.kernel.org with ESMTP id S263029AbTEGJfW (ORCPT ); Wed, 7 May 2003 05:35:22 -0400 Date: Wed, 7 May 2003 11:47:52 +0200 From: Andi Kleen To: =?iso-8859-1?Q?J=F6rn?= Engel Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] Fix .altinstructions linking failures Message-ID: <20030507094752.GA4050@averell> References: <20030506063055.GA15424@averell> <20030507092329.GA2389@wohnheim.fh-wedel.de> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20030507092329.GA2389@wohnheim.fh-wedel.de> User-Agent: Mutt/1.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org [cc list trimmed] On Wed, May 07, 2003 at 11:23:29AM +0200, Jörn Engel wrote: > I've been a bit sceptical of the whole .altinstructions idea, > self-modifying code opens a can of worms for anyone trying to do code > analysis (coverage, verification,...). But with this followup, I > personally pay money to get that stuff ripped out again. Ok. How much do you pay ? ;@) Seriously. To give some numbers. This is the maxi kernel (about 8MB .text, everything compiled in that compiles in 2.5.69) which is far too big to even even boot. 20 .exit.text 00005afa c0ada3d0 c0ada3d0 009db3d0 2**4 CONTENTS, ALLOC, LOAD, READONLY, CODE About 20k from 8MB On a realistic kernel that actually boots we are talking about 1-2KB, probably even less. If you really wanted to combat bloat there are a lot other areas where you can avoid much more than 2KB with minimum effort. Just go through include/linux/* and move a few unnecessary inlines away, that will help much more. If you want to save real memory attack mem_map, like I proposed earlier. -Andi P.S.: In case someone is interested: The hall of shame for the 2.5.69 SMP maxi kernel (stuff that doesn't build) currently is: Sound/Alsa (one driver doesn't compile), USB (3 drivers don't compile), MTD (lots of stuff doesn't compile). Everything else is quite good.