From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754152AbaBDJIk (ORCPT ); Tue, 4 Feb 2014 04:08:40 -0500 Received: from mail-ee0-f48.google.com ([74.125.83.48]:51913 "EHLO mail-ee0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751310AbaBDJI3 (ORCPT ); Tue, 4 Feb 2014 04:08:29 -0500 Date: Tue, 4 Feb 2014 10:08:25 +0100 From: Ingo Molnar To: David Rientjes Cc: Andrew Morton , Linus Torvalds , Borislav Petkov , LKML , X86 ML , Richard Weinberger , Borislav Petkov Subject: Re: [PATCH] Clarify CONFIG_DEBUG_INFO's bloaty nature Message-ID: <20140204090809.GA19156@gmail.com> References: <1391452183-2160-1-git-send-email-bp@alien8.de> <20140203145718.5bc9ba1619aff8ea0754b0ab@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * David Rientjes wrote: > On Mon, 3 Feb 2014, Andrew Morton wrote: > > > > > How do you define "huge bloat" if the size of vmlinux doesn't increase? > > > > > > Don't be silly. The size of all the object files increase *hugely*. > > > > yup, I disable this in my allmodconfig testing, to great effect. > > > > That being said, I do think the text should make clear that the bloat > > is a compile-time impact and not a runtime one. Something like > > > > --- a/lib/Kconfig.debug~lib-kconfigdebug-clarify-config_debug_infos-bloaty-nature-fix > > +++ a/lib/Kconfig.debug > > @@ -128,9 +128,9 @@ config DEBUG_INFO > > tools like crash, kgdb, LKCD, gdb, etc on the kernel. > > > > If you only want to have resolved symbols in kernel traces and > > - are not going to need support for those tools above, you don't need > > - to enable this as it is a huge bloat and build slowdown; > > - enable CONFIG_KALLSYMS instead. > > + are not going to need support for the above tools, you don't need > > + to enable this. It hugely bloat object files' on-disk sizes and slows > > + the build. Enable CONFIG_KALLSYMS instead. > > > > If unsure, say N. > > > > Um, I still don't think this is right since > CONFIG_DEBUG_INFO_REDUCED requires you to say yes here and that > config option actually specifies the tools for which it is > effective. Are you suggesting that we decouple CONFIG_DEBUG_INFO > from CONFIG_DEBUG_INFO_REDUCED and make CONFIG_DEBUG_INFO select the > reduced variant? Or... what? I think the right solution is what I suggested in another recent discussion: "So to reign in debuginfo in allyesconfig/allmodconfig builds we could do something like: config SAVE_TIME_AND_DISK_SPACE bool "Faster and leaner build object files: compile without debug info" default y choice prompt "Choose DEBUGINFO bloat level" depends on !SAVE_TIME_AND_DISK_SPACE default DEBUG_INFO_REDUCED help This option allows to select the debuginfo model. config DEBUG_INFO_REDUCED bool "Reduced amount of debugging information, 4x regular .o size" config DEBUG_INFO bool "Full debuginfo, 10x regular .o size, 'planet killer' version" endchoice That would default to Y and would disable debuginfo by default." Thanks, Ingo