From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932141AbWIIFUd (ORCPT ); Sat, 9 Sep 2006 01:20:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932145AbWIIFUd (ORCPT ); Sat, 9 Sep 2006 01:20:33 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:12009 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S932141AbWIIFUc (ORCPT ); Sat, 9 Sep 2006 01:20:32 -0400 Date: Sat, 9 Sep 2006 07:12:11 +0200 From: Ingo Molnar To: David Howells Cc: torvalds@osdl.org, akpm@osdl.org, benh@kernel.crashing.org, linux-kernel@vger.kernel.org, uclinux-dev@uclinux.org Subject: Re: [PATCH 2/3] FRV: Permit __do_IRQ() to be dispensed with Message-ID: <20060909051211.GA6922@elte.hu> References: <20060908153236.21015.56106.stgit@warthog.cambridge.redhat.com> <20060908153240.21015.67367.stgit@warthog.cambridge.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060908153240.21015.67367.stgit@warthog.cambridge.redhat.com> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: -2.9 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.9 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_50 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 0.5 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.5000] -0.1 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * David Howells wrote: > +#ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ > +#ifdef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ > +#ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ I think the myriad of arch switches and the resulting #ifdef noise, just to get rid of a _single_ unused global function, is pretty lame. (and that's of course not your fault) The real solution would be to use gcc -ffunction-sections plus ld --gc-sections to automatically get rid of unused global functions, at link time. I'm wondering how hard it would be to enhance kbuild to do that - x86_64 already uses -ffunction-sections (if CONFIG_REORDER), so the big question is how usable is ld --gc-sections. Such a feature would be quite important for embedded systems (and for RAM footprint in general) as it would save a significant amount of .text and .data. Ingo