Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753872Ab1EEW1o (ORCPT ); Thu, 5 May 2011 18:27:44 -0400 Received: from www.linutronix.de ([62.245.132.108]:34715 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752318Ab1EEW1n (ORCPT ); Thu, 5 May 2011 18:27:43 -0400 Date: Fri, 6 May 2011 00:27:20 +0200 (CEST) From: Thomas Gleixner To: werner cc: Christoph Lameter , Tejun Heo , Linus Torvalds , Pekka Enberg , Ingo Molnar , Jens Axboe , Andrew Morton , "H. Peter Anvin" , Linux Kernel Mailing List Subject: Re: [block IO crash] Re: 2.6.39-rc5-git2 boot crashs In-Reply-To: Message-ID: References: <20110505095421.GD30950@htj.dyndns.org> User-Agent: Alpine 2.02 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2716 Lines: 60 On Thu, 5 May 2011, werner wrote: > 90% of the config options, users don't know for what they are. Instead of > more and more new config features in, EVERY CONFIG PARAMETER WHAT THE KERNEL > CAN DETECT AT RUN TIME (at the beginning of booting) SHOULD BE THROWED OUT. > And the kernel should be compiled 'everythingyes' as default. Even then, > with all exotic (but nowadays happening) boot-necessary input/output hardware > included, my vmlinuz is only 10 MB big. Sufficient memory for run this > (together with an initrd for an installer) nowadays should exist on almost all > computers. All other, not-boot necessary modules are perhaps 50 MB, and since > the Atari time with 20 MB harddisks passed, there is NO REASON FOR COMPILE > SMALL THE KERNEL. Even on Android phones, compiling the kernel / modules 50 MB > big but using often only a part, dont hurt. But for emergency, instead of > completely configless, one could let 2 options for the kernel config: normal, > small (below 16 M memory). Provisorically, one could but one should not > include such a raw-selection menu in the kernel config, because to check and > maintain the dependences of their various single config parameters would be > big extra work. Instead of this, one should rigorously make more and more > config parameters definitively obsolete and reduce them by improving the > corresponding runtime ability of the kernel. Have a look outside of the x86 and "smartphone brag with your GBs of RAM" world and you'll see that there are - systems which really care about size reductions which are measured in kilobytes. - systems where runtime detection is impossible - systems where runtime detection is complete overkill in various aspects: boottime, memory footprint ... And you CANNOT put those requirements under a single CONFIG_VERY_SMALL=y fits it all thing simply because embedded devices have those fundamental different requirements vs. drivers, filesystems .... Aside of that config options are a pretty useful mechanism to debug problems. And in the context of that particular case you are barking up the completely wrong tree. The facts that - slub used the wrong macro - the CONFIG dependent x86 implementation of that this_cpu_* mess was crap to begin with are not an argument at all to go and impose a 100MB/50MB/16MB or whatever arbitrary choice you make limit of CONFIG_FITS_IT_ALL_* approach. That simply does not work. Thanks, tglx -- 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/