From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 3 May 2002 14:37:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 3 May 2002 14:37:08 -0400 Received: from web13505.mail.yahoo.com ([216.136.175.84]:47890 "HELO web13505.mail.yahoo.com") by vger.kernel.org with SMTP id ; Fri, 3 May 2002 14:37:05 -0400 Message-ID: <20020503183701.32163.qmail@web13505.mail.yahoo.com> Date: Fri, 3 May 2002 11:37:01 -0700 (PDT) From: Tony Luck Subject: Re: Virtual address space exhaustion (was Discontigmem virt_to_page() ) To: linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Richard B. Johnson wrote: > One of the Unix characteristics is that the kernel > address space is shared with each of the process > address space. This hasn't been an absolute requirement. There have been 32-bit Unix implementations that gave separate 4G address spaces to the kernel and to each user process. The only real downside to this is that copyin()/copyout() are more complex. Some processors provided special instructions to access user-mode addresses from kernel to mitigate this complexity. -Tony __________________________________________________ Do You Yahoo!? Yahoo! Health - your guide to health and wellness http://health.yahoo.com