Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965106Ab2JCRqZ (ORCPT ); Wed, 3 Oct 2012 13:46:25 -0400 Received: from mail-qa0-f53.google.com ([209.85.216.53]:48389 "EHLO mail-qa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965075Ab2JCRqX (ORCPT ); Wed, 3 Oct 2012 13:46:23 -0400 Date: Wed, 3 Oct 2012 19:46:18 +0200 From: Frederic Weisbecker To: Greg Kroah-Hartman Cc: "Paul E. McKenney" , Kees Cook , linux-kernel@vger.kernel.org, "Eric W. Biederman" , Serge Hallyn , "David S. Miller" , Andrew Morton Subject: Re: [PATCH] make CONFIG_EXPERIMENTAL invisible and default Message-ID: <20121003174606.GB637@somewhere> References: <20121002195042.GA16087@www.outflux.net> <20121003132538.GE13192@linux.vnet.ibm.com> <20121003161702.GA22008@kroah.com> <20121003164712.GF2527@linux.vnet.ibm.com> <20121003172142.GA5061@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121003172142.GA5061@kroah.com> 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 Content-Length: 3378 Lines: 62 On Wed, Oct 03, 2012 at 10:21:42AM -0700, Greg Kroah-Hartman wrote: > On Wed, Oct 03, 2012 at 09:47:12AM -0700, Paul E. McKenney wrote: > > On Wed, Oct 03, 2012 at 09:17:02AM -0700, Greg Kroah-Hartman wrote: > > > On Wed, Oct 03, 2012 at 06:25:38AM -0700, Paul E. McKenney wrote: > > > > On Tue, Oct 02, 2012 at 12:50:42PM -0700, Kees Cook wrote: > > > > > This config item has not carried much meaning for a while now and is > > > > > almost always enabled by default. As agreed during the Linux kernel > > > > > summit, it should be removed. As a first step, remove it from being > > > > > listed, and default it to on. Once it has been removed from all > > > > > subsystem Kconfigs, it will be dropped entirely. > > > > > > > > > > CC: Greg KH > > > > > CC: "Eric W. Biederman" > > > > > CC: Serge Hallyn > > > > > CC: "Paul E. McKenney" > > > > > CC: Andrew Morton > > > > > CC: Frederic Weisbecker > > > > > Signed-off-by: Kees Cook > > > > > --- > > > > > > > > > > This is the first of a series of 202 patches removing EXPERIMENTAL from > > > > > all the Kconfigs in the tree. Should I send them all to lkml (with all > > > > > the associated CCs), or do people want to cherry-pick changes from my > > > > > tree? I don't want to needlessly flood the list. > > > > > > > > > > http://git.kernel.org/?p=linux/kernel/git/kees/linux.git;a=shortlog;h=refs/heads/experimental > > > > > > > > > > I figure this patch can stand alone to at least make EXPERIMENTAL go > > > > > away from the menus, and give us a taste of what the removal would do > > > > > to builds. > > > > > > > > OK, I will bite... How should I flag an option that is initially only > > > > intended for those willing to take some level of risk? > > > > > > In the text say "You really don't want to enable this option, use at > > > your own risk!" Or something like that :) > > > > OK, so the only real hope for experimental features is to refrain from > > creating a config option for them, so that people wishing to use them > > must modify the code? Or is the philosophy that we keep things out of > > tree until we are comfortable with distros turning them on? > > I think that should have been your philosophy for a long time, as they > turn on everything, and I don't blame them. > Why would we have included > it in the kernel tree, unless we wanted people to use the option? A solution could be to add that option under CONFIG_DEBUG_KERNEL and specify that it must only be enabled by developers for specific reasons (overhead, security). CONFIG_PROVE_LOCKING falls into that category, right? We have CONFIG_RCU_USER_QS that is a specific case. It's an intermediate state before we implement a true CONFIG_NO_HZ_FULL. But the option is useless on its own for users. Worse, it introduces a real overhead. OTOH we want it to be upstream to make the development of full tickless feature more incremental. Perhaps we should put that under CONFIG_DEBUG_KERNEL. -- 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/