From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761594AbYDUUGw (ORCPT ); Mon, 21 Apr 2008 16:06:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755597AbYDUUGm (ORCPT ); Mon, 21 Apr 2008 16:06:42 -0400 Received: from moutng.kundenserver.de ([212.227.126.183]:58846 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755060AbYDUUGl (ORCPT ); Mon, 21 Apr 2008 16:06:41 -0400 Date: Mon, 21 Apr 2008 22:05:38 +0200 (CEST) From: Bodo Eggert <7eggert@gmx.de> To: Daniel Hazelton cc: 7eggert@gmx.de, Adrian Bunk , Alan Cox , Shawn Bohrer , Ingo Molnar , Andrew Morton , Linux Kernel Mailing List , Arjan van de Ven , Thomas Gleixner , Andi Kleen Subject: Re: x86: 4kstacks default In-Reply-To: <200804201659.52902.dhazelton@enter.net> Message-ID: References: <200804201659.52902.dhazelton@enter.net> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=us-ascii X-be10.7eggert.dyndns.org-MailScanner-Information: See www.mailscanner.info for information X-be10.7eggert.dyndns.org-MailScanner: Found to be clean X-be10.7eggert.dyndns.org-MailScanner-From: 7eggert@gmx.de X-Provags-ID: V01U2FsdGVkX1+ZOdpPoyaUGBZN0Wi/73sCSSjT57j6WRARetq 1zgmG/YuVcT8p14TS5rfGFbfWIxrIiw4DcXirSFwkkfrtzFS+R ylCm6cZ5MNOwH1K8iLAqA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 20 Apr 2008, Daniel Hazelton wrote: > On Sunday 20 April 2008 16:23:45 Bodo Eggert wrote: > > Daniel Hazelton wrote: > > > On Sunday 20 April 2008 08:27:14 Andi Kleen wrote: > > >> Adrian Bunk writes: > > >> > 6k is known to work, and there aren't many problems known with 4k. > > >> > > > >> > And from a QA point of view the only way of getting 4k thoroughly > > >> > tested > > >> > > >> But you have to first ask why do you want 4k tested? Does it serve > > >> any useful purpose in itself? I don't think so. Or you're saying > > >> it's important to support 50k kernel threads on 32bit kernels? > > > > > > Andi, you're the only one I've seen seriously pounding the "50k threads" > > > thing - I don't think anyone is really fooled by the straw-man, so I'd > > > suggest you drop it. > > > > > > The real issue is that you think (and are correct in thinking) that > > > people are idiots. Yes, there will be breakages if the default is changed > > > to 4k stacks - but if people are running new kernels on boxes that'll hit > > > stack use problems (that *AREN'T* related to ndiswrapper) and haven't > > > made sure that they've configured the kernel properly, then they deserve > > > the outcome. It isn't the job of the Linux Kernel to protect the > > > incompetent - nor is it the job of linux kernel developers to do such. > > > > It's the job of the kernel developers to mark experimental and broken > > options, and to put a warning: > > > > "This will break stacking of drivers, especially if disk manager, xfs, RAID > > and nfs are used. Yes, linux is broken by default, but only if you intend > > to set up a reliable system, so this will be OK!" > > > > into the help text, instead of expecting each admin to read lkml. > > Note that I've yet to meet a competent admin that creates brand new > configurations each time they build a new kernel for a machine. Once is enough, and if you build a costom kernel, you'll certainly not want to start from the distribution's allmodconfig. > Usually they > have a "default configuration" for each machine that gets updated each time a > new kernel is built. Usually they don't change working options. And since > changing things to 4K stacks default would cause a new option - the "8K > stacks" option to show up in a "make oldconfig" run - the admin would see it > and, hopefully, check the help text and see that it his system, with a deeply > stacked driver system (nfs+xfs+raid, for example) and set the 8K stacks > option to "Y". The help text does not yet say anything about crashing. > As I said, it isn't the job of the kernel or kernel developers to protect the > incompetent (or the lazy). It's only incompetent if it's reasonable to expect a crashing kernel to result from chosing the default values. -- bus error. passengers dumped.