From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756739AbZEKChL (ORCPT ); Sun, 10 May 2009 22:37:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754445AbZEKCg4 (ORCPT ); Sun, 10 May 2009 22:36:56 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:50892 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753572AbZEKCgz (ORCPT ); Sun, 10 May 2009 22:36:55 -0400 To: Kay Sievers Cc: Arjan van de Ven , Alan Cox , Peter Zijlstra , Greg KH , Andrew Morton , Fabio Comolli , Greg KH , linux-kernel@vger.kernel.org Subject: Re: [patch 00/13] devtmpfs patches References: <20090509143742.GA27663@kroah.com> <20090509150853.GA32394@suse.de> <20090509082233.32cbb8e4@infradead.org> <20090509161923.GA942@suse.de> <20090509223454.4642753d.akpm@linux-foundation.org> <20090510152005.GA9461@suse.de> <1241980263.9562.380.camel@laptop> <20090510221901.30c1c5a5@lxorguk.ukuu.org.uk> <20090510170016.1e3a4d97@infradead.org> From: ebiederm@xmission.com (Eric W. Biederman) Date: Sun, 10 May 2009 19:36:46 -0700 In-Reply-To: (Kay Sievers's message of "Mon\, 11 May 2009 03\:22\:53 +0200") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-XM-SPF: eid=;;;mid=;;;hst=in02.mta.xmission.com;;;ip=67.169.126.145;;;frm=ebiederm@xmission.com;;;spf=neutral X-SA-Exim-Connect-IP: 67.169.126.145 X-SA-Exim-Rcpt-To: kay.sievers@vrfy.org, linux-kernel@vger.kernel.org, greg@kroah.com, fabio.comolli@gmail.com, akpm@linux-foundation.org, gregkh@suse.de, peterz@infradead.org, alan@lxorguk.ukuu.org.uk, arjan@infradead.org X-SA-Exim-Mail-From: ebiederm@xmission.com X-SA-Exim-Version: 4.2.1 (built Thu, 25 Oct 2007 00:26:12 +0000) X-SA-Exim-Scanned: No (on in02.mta.xmission.com); Unknown failure Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Kay Sievers writes: > On Mon, May 11, 2009 at 02:00, Arjan van de Ven wrote: >> (and it seems to be irrelevant to the devtmpfs discussion anyway since >> Eric Biederman has shown that pulling the device numbers out of sysfs >> is basically free... even though it'd be nice to give that some help to >> make it a nice index) > Devtmpfs is the simplest, is the fastest, is the most reliable, and it > is the most flexible FLEXIBLE? > option for us. And still, nobody will be forced > to use it, it's entirely optional. For our systems, we decided to do > it that way, and we ship it already in the distro, and if there are no > substantial problems coming up, which we don't expect, we will > continue using it. Yes but you are asking all of us to maintain it. Forever in perpetuity. A better case needs to be made than you have already shipped the code. I'm sorry you decided to ship the code before getting a review. I guess that is the definition of an experimental feature. One not in the upstream kernel. > You might not like it for whatever reason. I think your justification for this ``feature'' is strongly flawed. You claim to save 2 seconds of a process that should take less than a tenth of a second. You claim flexibility while removing user space from the policy loop. You claim speed increases when comparing to a dog slow non-tuned implementation. > And we consider this problem as solved. What backroom have you had that discussion? You are presenting this as a decision already made. I think you are not playing well with others. I don't see a case having been made that the existing user space interface is broken. Just that the udev implementation is slow. I think a slow user space application is simply not a justification for putting code in the kernel. I think a developer using faulty arguments for their code likely has not thought things through and that is enough reason to call suspicion onto the code in my opinion. Eric