From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752650AbZHHRVa (ORCPT ); Sat, 8 Aug 2009 13:21:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752418AbZHHRV3 (ORCPT ); Sat, 8 Aug 2009 13:21:29 -0400 Received: from kroah.org ([198.145.64.141]:37743 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752166AbZHHRV3 (ORCPT ); Sat, 8 Aug 2009 13:21:29 -0400 Date: Sat, 8 Aug 2009 10:11:24 -0700 From: Greg KH To: Al Boldi Cc: Chris Friesen , Andi Kleen , Alan Cox , linux-kernel@vger.kernel.org, Kay Sievers , Jan Blunck , gregkh@suse.de, Harald Hoyer , Scott James Remnant Subject: Re: [PATCH] Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev Message-ID: <20090808171124.GA357@kroah.com> References: <20090805171513.GA10443@kroah.com> <200908080017.31376.a1426z@gawab.com> <20090807222449.GA31416@kroah.com> <200908081214.39456.a1426z@gawab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200908081214.39456.a1426z@gawab.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Aug 08, 2009 at 12:14:39PM +0300, Al Boldi wrote: > Greg KH wrote: > > On Sat, Aug 08, 2009 at 12:17:31AM +0300, Al Boldi wrote: > > > For devtmpfs to be a realistic replacement for static /dev, it has to > > > be comparable to static /dev in both speed and size. > > > > Since when is this requirement necessary? You want something for free > > in both speed and size? Well, you got it in speed, but not size, it > > will take up memory that is swapable, and a tiny ammount of non-swapable > > kernel memory for the code. > > Not so tiny when you count in the hotplug dependency. devtmpfs does not rely on hotplug at all. > > > WRT speed, there should be no slowdown and it should be just as fast > > > as a "tar -xp < dev.tar". > > > > Again, where is this requirement coming from? > > > > Have you timed devtmpfs? > > Not yet, I am still waiting for the latest patch against .30. I already pointed you at it. > > > WRT size, it should not be dependent on hotplug, and instead offer > > > hotplug as an option. > > > > Um, again, who made up such a requirement? Are you running systems > > today with CONFIG_HOTPLUG disabled? If so, how well is that working for > > you? > > It's working out quite well. I don't like hotplug, it's too slow. I always > turn it and module-autoloading off, to achieve a much more responsive system. What becomes "more responsive"? What is too slow? Anyway, this is quite off-topic for the original patch. If you have problems/issues with udev and CONFIG_HOTPLUG, let's take that to the linux-hotplug@vger.kernel.org list. thanks, greg k-h