From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754743AbZEANYb (ORCPT ); Fri, 1 May 2009 09:24:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756088AbZEANYW (ORCPT ); Fri, 1 May 2009 09:24:22 -0400 Received: from mail-ew0-f176.google.com ([209.85.219.176]:50797 "EHLO mail-ew0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754206AbZEANYW (ORCPT ); Fri, 1 May 2009 09:24:22 -0400 MIME-Version: 1.0 In-Reply-To: <20090501141846.4b833700@lxorguk.ukuu.org.uk> References: <1241097822.2516.3.camel@poy> <20090430222900.c13b63d5.akpm@linux-foundation.org> <20090501061701.GB19234@kroah.com> <20090430234312.a63fa5cf.akpm@linux-foundation.org> <20090501065527.GA19773@kroah.com> <20090501120359.05bacb48@lxorguk.ukuu.org.uk> <20090501141846.4b833700@lxorguk.ukuu.org.uk> From: Kay Sievers Date: Fri, 1 May 2009 15:24:01 +0200 Message-ID: Subject: Re: [PATCH] driver-core: devtmpfs - driver core maintained /dev tmpfs To: Alan Cox Cc: Greg KH , Andrew Morton , linux-kernel , Jan Blunck Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 1, 2009 at 15:18, Alan Cox wrote: >> No tool ever has a chance to get to the information only available at >> early kernel init. All such tools will need to "replay" what the >> kernel already did. This is intended to save us from doing this, and >> retain the information which is there, but lost at the moment the >> tools have the first chance to run. > > Serious question - which is the better problem to fix ? I'm very sure, you can not fix it outside the kernel. Or do you have an idea how to create the missing device nodes for device without crawling sysfs, when the first userspace process is started? >> It's not about a sucking tool, its just impossible. And there is no >> space wasted, it's a single string for a very few subsystems, an >> nothing is stored per device. > > Plus code plus tmpfs nodes (the latter are not quite free because you > create unneeded ones versus udev but I agree that is noise for most users) It's exactly the same as udev. Udev creates a node for every device the core registers in tmpfs. This tmpfs is mounted by the kernel and pre-populated with this, not by udev, that's all the difference it has. There is not a single node more than before. Thanks, Kay