From owner-freebsd-hackers Tue Mar 13 17:41:54 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from mail.cs.umn.edu (mail.cs.umn.edu [128.101.34.200]) by hub.freebsd.org (Postfix) with ESMTP id 7551E37B718 for ; Tue, 13 Mar 2001 17:41:51 -0800 (PST) (envelope-from rakshe@cs.umn.edu) Received: from mercury.cs.umn.edu (mercury.cs.umn.edu [128.101.34.120]) by mail.cs.umn.edu (8.9.3/8.9.3) with ESMTP id TAA16144 for ; Tue, 13 Mar 2001 19:41:50 -0600 (CST) Received: from localhost (rakshe@localhost) by mercury.cs.umn.edu (8.9.3/8.9.0) with ESMTP id TAA21606 for ; Tue, 13 Mar 2001 19:41:50 -0600 (CST) X-Authentication-Warning: mercury.cs.umn.edu: rakshe owned process doing -bs Date: Tue, 13 Mar 2001 19:41:50 -0600 (CST) From: Rohit Rakshe To: Subject: Copying user <---> kernel Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Hello, I am sure people have thought about this one, but just that I could not find any discussions about it: Consider a server which receives data over network, does some operations on the data and sends it back over the network. The kernel could spent most of its time copying data to and from user space. (the operations are performed in the user space). The following can be done to avoid this overhead: Say, I want to copy a page from user space to kernel, I can just pin it in physical memory; then attach it to kernel page table. (similar thing for other way round). Is this kinda thing implemented ? If not, is it feasible ? Thanks everyone ! - Rohit To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message