From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752954Ab1JJIsQ (ORCPT ); Mon, 10 Oct 2011 04:48:16 -0400 Received: from filtteri5.pp.htv.fi ([213.243.153.188]:57444 "EHLO filtteri5.pp.htv.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752543Ab1JJIsP (ORCPT ); Mon, 10 Oct 2011 04:48:15 -0400 Date: Mon, 10 Oct 2011 11:48:11 +0300 From: Adrian Bunk To: Ingo Molnar Cc: Josh Triplett , Linus Torvalds , linux-kernel@vger.kernel.org, Frederic Weisbecker , Sam Ravnborg Subject: Re: Please revert "debug: Make CONFIG_EXPERT select CONFIG_DEBUG_KERNEL to unhide debug options" Message-ID: <20111010084811.GG4586@localhost.pp.htv.fi> References: <20110930134245.GB21474@localhost.pp.htv.fi> <20110930150519.GA7980@leaf> <20110930155012.GC9049@localhost.pp.htv.fi> <20111010072946.GA29035@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20111010072946.GA29035@elte.hu> 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 On Mon, Oct 10, 2011 at 09:29:48AM +0200, Ingo Molnar wrote: > * Adrian Bunk wrote: >... > I think you are wrong not just about that detail but about the whole > premise of your complaint as well: > > > config DEBUG_BUGVERBOSE > > - bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT > > + bool "Verbose BUG() reporting (adds 70K)" if EXPERT > > > > This part of the patch would have been the correct and complete > > solution for DEBUG_BUGVERBOSE. > > Not really - it's a debugging-only option and when i turn on > CONFIG_DEBUG_KERNEL I expect to have full config control over all > debug options - with sane defaults provided. Then you would have to remove the dependency on EXPERT from the prompt, and allow unsetting DEBUG_BUGVERBOSE with EXPERT=n, DEBUG_KERNEL=y. Note that this is completely unrelated to the commit we are discussing, since commit f505c553 has no effect in the EXPERT=n case you are discussing here. > I definitely don't want a debugging option to depend on > CONFIG_EXPERT. DEBUG_BUGVERBOSE does not depend on EXPERT. But EXPERT is currently required for disabling it. This part of our discussion boils down to the following options: 1. DEBUG_KERNEL allows a user to enable additional debugging 2. DEBUG_KERNEL gives a user full control over all debug options Traditionally it was 1., to tell a user reporting a bug that he should enable additional debugging in his kernel - without him accidentally disabling useful debugging. Again, this part of the discussion is unrelated to commit f505c553. > CONFIG_EXPERT is a superset to all that: it implies config control > over all debug options *and* over many other kernel components as > well. I don't see the advantage that EXPERT=y is now unconditionally enabling the DEBUG_KERNEL knob. When I am an "expert", why can't I still decide myself globally if I want to enable more debugging or not? Another problem is that we have code using "#ifdef CONFIG_DEBUG_KERNEL" so enabling EXPERT for making your kernel smaller can make your kernel bigger, but such usages should anyway get own config options. > This is a pretty easy model to think about. There are many options in the kernel that only enable seeing other config options. With that model, shouldn't EXPERT also have select MISC_FILESYSTEMS and many other similar select's? The point I am trying to make here is that there are many convenience config options that only exist to allow a user to hide a bunch of options he is not interested in, and DEBUG_KERNEL is one of them. [1] > > The crazy select added in commit f505c553 is wrong. > > Why? Your original message does not explain it. It is not needed for what it was claimed it was needed for, and it is a bad idea in general. If I didn't explain that properly that was my fault, I hope the explanation in this email is better. > Thanks, > > Ingo cu Adrian [1] ignoring the buggy code using "#ifdef CONFIG_DEBUG_KERNEL" -- "Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed