From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261322AbVGBXDO (ORCPT ); Sat, 2 Jul 2005 19:03:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261323AbVGBXDO (ORCPT ); Sat, 2 Jul 2005 19:03:14 -0400 Received: from willy.net1.nerim.net ([62.212.114.60]:13581 "EHLO willy.net1.nerim.net") by vger.kernel.org with ESMTP id S261322AbVGBXDH (ORCPT ); Sat, 2 Jul 2005 19:03:07 -0400 Date: Sun, 3 Jul 2005 01:03:03 +0200 From: Willy Tarreau To: Mike Bell , linux-kernel@vger.kernel.org Subject: Re: updating kernel to 2.6.13-rc1 from 2.6.12 + CONFIG_DEVFS_FS + empty /dev Message-ID: <20050702230303.GA27261@alpha.home.local> References: <20050629224040.GB18462@kroah.com> <1120137161.42c3efc93b36c@imp1-q.free.fr> <20050630155453.GA6828@kroah.com> <42C455C1.30503@free.fr> <20050702053711.GA5635@kroah.com> <42C640AC.1020602@free.fr> <20050702082218.GM8907@alpha.home.local> <42C659B2.8010002@free.fr> <20050702100349.GA25749@alpha.home.local> <20050702201356.GA32409@mikebell.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050702201356.GA32409@mikebell.org> User-Agent: Mutt/1.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jul 02, 2005 at 01:13:58PM -0700, Mike Bell wrote: > On Sat, Jul 02, 2005 at 12:03:49PM +0200, Willy Tarreau wrote: > > They cost almost nothing, and in all cases, far less than the required code > > to autodetect them. > > I beg to differ on that. As ndevfs has shown, the code required to > create a device node from kernel space is actually very minimal, when > you utilize all the infrastructure already available to you in the > kernel. libfs has most of what you need, the rest is easily stolen from > ramfs. Almost undoubtebly much less than all those device nodes, > especially when you consider the need to be able to perform chown/chmod > on nodes (thus they can't be stored in the read-only flash image, but > must instead be created at each boot on a kernel-generated filesystem > like ramfs) Well, here on my firewall, the /.preinit script is 1.7 kB and the init binary which does everything (mkdir,mknod,chmod,chown,mount,...) is 5.6 kB. I doubt you can enable devfs in a kernel for less than 8 kB. One /tmpfs entry consumes about 600 bytes of RAM, which is still fairly acceptable IMHO. > devfs not utilizing it is perfectly explainable by the fact none of it > was around way back when devfs was created. Back then kernel generated > filesystems were proc, proc and proc. proc is pretty ugly too. Regards, Willy