Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757232AbZDUDQn (ORCPT ); Mon, 20 Apr 2009 23:16:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753504AbZDUDQe (ORCPT ); Mon, 20 Apr 2009 23:16:34 -0400 Received: from casper.infradead.org ([85.118.1.10]:54168 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752365AbZDUDQe (ORCPT ); Mon, 20 Apr 2009 23:16:34 -0400 Date: Mon, 20 Apr 2009 20:18:26 -0700 From: Arjan van de Ven To: Linus Torvalds Cc: Tim Abbott , Linux kernel mailing list , Anders Kaseorg , Waseem Daher , Denys Vlasenko , Rusty Russell , Andi Kleen , "H. Peter Anvin" , Stephen Rothwell , Jeff Arnold , Andrew Morton , Jon Masters Subject: Re: [PATCH v2 0/4] Add support for compiling with -ffunction-sections -fdata-sections Message-ID: <20090420201826.7c1f7f06@infradead.org> In-Reply-To: References: <1238973278-31735-1-git-send-email-tabbott@mit.edu> Organization: Intel X-Mailer: Claws Mail 3.7.0 (GTK+ 2.14.7; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2125 Lines: 50 On Mon, 20 Apr 2009 17:35:32 -0700 (PDT) Linus Torvalds wrote: > > > On Mon, 20 Apr 2009, Tim Abbott wrote: > > > > I assume you're only worried about toolchain problems for people > > who are actually using the -ffunction-sections option. Would it > > help if the -ffunction-sections compilation option were marked as > > experimental until proven otherwise? > > The thing is, people will enable them, and then maybe the compiler > _appears_ to work, and things don't boot, and people spend tons of > time chasing down somethign that just turns out to be a tools issue > and not a kernel issue at all. And nobody happens to realize that > what's up is that the person who reported the regression had enabled > an experimental feature. > > > If you're not willing to merge even an experimental option for > > -ffunction-sections, would you at least be willing to merge the > > first three patches in the patch series? Compiling with > > -ffunction-sections would not be supported by the mainline kernel, > > so any toolchain issues with it would not be your problem. But any > > vendor that wants to take advantage of -ffunction-sections would > > still be able to use it without having to maintain 300 lines of > > scattered changes to the kernel. > > Are there any advantages outside of the size things? we can probably drop a ton of ifdefs... an alternative approach would be to have a special build target that uses this, but makes a 2nd vmlinux, and then runs a diff on the symbols against the regular one... and finds which functions got dropped. Some patient soul can then go about and stick in ifdefs and stuff... (or delete the totally not-used-by-anyone functions entirely) -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org -- 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/