Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267769AbUJRT6v (ORCPT ); Mon, 18 Oct 2004 15:58:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267720AbUJRTzz (ORCPT ); Mon, 18 Oct 2004 15:55:55 -0400 Received: from mail.scitechsoft.com ([63.195.13.67]:55208 "EHLO mail.scitechsoft.com") by vger.kernel.org with ESMTP id S267713AbUJRTuu (ORCPT ); Mon, 18 Oct 2004 15:50:50 -0400 From: "Kendall Bennett" Organization: SciTech Software, Inc. To: Alan Cox Date: Mon, 18 Oct 2004 12:50:41 -0700 MIME-Version: 1.0 Subject: Re: Running user processes in kernel mode; Java and .NET support in kernel CC: Linux Kernel Mailing List Message-ID: <4173BC21.24859.11899F91@localhost> In-reply-to: <1097980064.13433.12.camel@localhost.localdomain> References: <82fa66380410152111143f75ec@mail.gmail.com> X-mailer: Pegasus Mail for Windows (4.21c) Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Content-description: Mail message body X-Spam-Flag: NO Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1543 Lines: 41 Alan Cox wrote: > Why would I care ? I need the MMU for paging and to avoid > fragmentation of the system. If I have the MMU on then memory > protection checks are free. > > Except in 4G/4G mode syscalls are extremely cheap too nowdays. Yes, but kernel mode support in user programs would allow user mode device drivers to do stuff that currently cannot be done at all from user space such as handling interrupts and scheduling DMA operations. Just think about how nice it would be if the kernel level DRI driver modules that are currently completely separate from the user space X drivers could be all in one place? Then users would no longer have to worry about making sure they upgrade their kernel so it has the correct kernel module installed at the same time that they upgrade X or get new drivers for their X server. IMHO I am not sure how much speedup you would gain from kernel mode Linux for user space programs (it might surprise us, or maybe it isn't much), but the ability to support user mode device drivers would be good IMHO, especially for graphics. Regards, --- Kendall Bennett Chief Executive Officer SciTech Software, Inc. Phone: (530) 894 8400 http://www.scitechsoft.com ~ SciTech SNAP - The future of device driver technology! ~ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/