Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755583Ab0FNIcf (ORCPT ); Mon, 14 Jun 2010 04:32:35 -0400 Received: from metis.ext.pengutronix.de ([92.198.50.35]:54072 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755525Ab0FNIcc (ORCPT ); Mon, 14 Jun 2010 04:32:32 -0400 Date: Mon, 14 Jun 2010 10:32:14 +0200 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= To: Linus Torvalds Cc: Daniel Walker , Russell King , Kevin Hilman , Linux Kernel Mailing List , linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: ARM defconfig files Message-ID: <20100614083214.GA2104@pengutronix.de> References: <20100603074548.GA12104@flint.arm.linux.org.uk> <20100603181010.GA25779@flint.arm.linux.org.uk> <1275589230.23384.19.camel@c-dwalke-linux.qualcomm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) X-SA-Exim-Connect-IP: 2001:6f8:1178:2:215:17ff:fe12:23b0 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4652 Lines: 127 Hello, [Added linux-arm-kernel ML to Cc, note that it's moderated for non-subscribers.] On Thu, Jun 03, 2010 at 11:21:59AM -0700, Linus Torvalds wrote: > > > On Thu, 3 Jun 2010, Daniel Walker wrote: > > > > I don't see how we can do without defconfigs altogether tho. I mean , if > > you want to run a Beagle board or a Nexus one we can't just give the > > users a slim ARM config and let them troll through 1000's of drivers > > trying to find just those ones that work on their given board. > > Well, you also don't need the full defconfig's with the kernel. > > Right now they are just noise. They actually _hide_ things, because > diffstat (and dirstat) information becomes pointless, and the diffs become > totally unreadable by any human (trust me - when the choice is between > "search for next relevant diff" or "blast it, I can't be bothered with > walking through this crap", quite often the choice is the latter). I wrote a script that throws out all unneeded lines in all arm defconfigs that don't influence the resulting .config for .34 and .35-rc1 and compared .34<->.35-rc with .34-reduced<->.35-rc1-reduced. Here are the results: $ git diff --dirstat v2.6.34 v2.6.35-rc1 arch/arm 11.8% arch/arm/configs/ 10.0% arch/arm/mach-msm/ 10.8% arch/arm/mach-omap2/ 4.8% arch/arm/mach-pxa/ 4.5% arch/arm/mach-s5pc100/ 3.3% arch/arm/mach-s5pv210/ 4.4% arch/arm/mach-spear3xx/ 3.1% arch/arm/mach-ux500/ 5.1% arch/arm/plat-s5pc1xx/ 3.1% arch/arm/plat-samsung/ 38.2% arch/arm/ $ git diff --dirstat arm/defconfig/reduced-v2.6.34 arm/defconfig/reduced-v2.6.35-rc1 arch/arm 3.1% arch/arm/mach-davinci/ 11.3% arch/arm/mach-msm/ 12.2% arch/arm/mach-omap2/ 5.4% arch/arm/mach-pxa/ 5.1% arch/arm/mach-s5pc100/ 3.7% arch/arm/mach-s5pv210/ 5.0% arch/arm/mach-spear3xx/ 3.5% arch/arm/mach-ux500/ 5.8% arch/arm/plat-s5pc1xx/ 3.5% arch/arm/plat-samsung/ 40.9% arch/arm/ $ git diff --dirstat=0 arm/defconfig/reduced-v2.6.34 arm/defconfig/reduced-v2.6.35-rc1 arch/arm | grep config 1.1% arch/arm/configs/ $ git diff --shortstat v2.6.35-rc1 arm/defconfig/reduced-v2.6.35-rc1 177 files changed, 652 insertions(+), 194157 deletions(-) (The insertions above are only moved lines I think, I didn't check them all.) The branches arm/defconfig/reduced-v2.6.34 and arm/defconfig/reduced-v2.6.35-rc1 are available at my repo at git://git.pengutronix.de/git/ukl/linux-2.6.git . (There is a gitweb at http://git.pengutronix.de/?p=ukl/linux-2.6.git) So maintaining these minimal defconfigs would have reduced the defconfig noise from 11.8% down to 1.1%. And probably it could be considerably reduced further with constructs like: config HAVE_MTD_NAND_MXC bool config MTD_NAND_MXC tristate "MXC NAND support" ... default m if HAVE_MTD_NAND_MXC help ... ... config MACH_MX27ADS ... select HAVE_MTD_NAND_MXC . Compared with selecting everything in Kconfig files this approach allows further tweaking of a config. (E.g. "I have a mx27ads machine, but I don't need nand support.") Compared with the SAT-Solver it's an idea that works today. One downside of this approach (when done with my script only) is that too much is removed. E.g. in mx3_defconfig CONFIG_ARCH_MX3 is removed. This is OK from a logical POV but then changing the default of the corresponding choice (and I intend to do that in the near future) would break this defconfig. I can share my script and I'm willing to support maintaining the minimality of the defconfig files if they are an acceptable (maybe intermediate) step for Linus. Together with the efforts to reduce the number of defconfigs as thought about in other mails of this thread the situation should become quite better for Linus. (I'm currently working on merging support for all Freescale SoCs into a single mach- directory and so merge mx1_defconfig, mx21_defconfig, mx27_defconfig, mx31pdk_defconfig, mx3_defconfig and mx51_defconfig.) Linus: I would really appreciate if you wouldn't remove all (or nearly all) defconfig files. I think you would force a quicker solution to this problem, but during that time the ARM community would loose compile coverage. Thoughts on this? Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-K?nig | Industrial Linux Solutions | http://www.pengutronix.de/ | -- 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/