From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266663AbUHaF5B (ORCPT ); Tue, 31 Aug 2004 01:57:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266684AbUHaF5B (ORCPT ); Tue, 31 Aug 2004 01:57:01 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:5251 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S266663AbUHaF47 (ORCPT ); Tue, 31 Aug 2004 01:56:59 -0400 Message-ID: <4134131D.6050001@pobox.com> Date: Tue, 31 Aug 2004 01:56:45 -0400 From: Jeff Garzik User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.2) Gecko/20040803 X-Accept-Language: en-us, en MIME-Version: 1.0 To: "Bill Huey (hui)" CC: Linus Torvalds , Tom Vier , linux-kernel@vger.kernel.org Subject: Re: Userspace file systems & MKs (Re: silent semantic changes with reiser4) References: <1093480940.2748.35.camel@entropy> <20040826044425.GL5414@waste.org> <1093496948.2748.69.camel@entropy> <20040826053200.GU31237@waste.org> <20040826075348.GT1284@nysv.org> <20040826163234.GA9047@delft.aura.cs.cmu.edu> <20040831033950.GA32404@zero> <413400B6.6040807@pobox.com> <20040831053055.GA8654@nietzsche.lynx.com> In-Reply-To: <20040831053055.GA8654@nietzsche.lynx.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Bill Huey (hui) wrote: > DragonFly BSD, the only remotely functional open source BSD project on this > planet, has plans in place to push certain kernel components like their VFS > layer into userspace for easier debugging, testing and other things that go That violates Jeff's First Rule, put the fast path stuff in the kernel. > with developing file systems easily. If they back it with something like C++ > for doing constructor style type conversion on top of overloaded operators > to back VFS data structure translation, could easily import stuff like most > Linux file systems without major restructuring, say, if they had their > translation library written. In this case, userspace kernel systems have > some serious programming advantages over traditional kernels. Sounds like security would be a pain in the ass :) > They're also pushing an async syscall model to support a non-1:1 threading > system for userspace unlike what Linux has done with futexes. It'll allow messaging passing is also known as "really slow C function calls" My PCI bus passes messages all the time. A message is in the eye of the beholder. Jeff