From owner-freebsd-arch Wed Feb 7 14:33:19 2001 Delivered-To: freebsd-arch@freebsd.org Received: from smtp04.primenet.com (smtp04.primenet.com [206.165.6.134]) by hub.freebsd.org (Postfix) with ESMTP id 2F26737B6BA; Wed, 7 Feb 2001 14:33:02 -0800 (PST) Received: (from daemon@localhost) by smtp04.primenet.com (8.9.3/8.9.3) id PAA01063; Wed, 7 Feb 2001 15:27:40 -0700 (MST) Received: from usr08.primenet.com(206.165.6.208) via SMTP by smtp04.primenet.com, id smtpdAAAiway1b; Wed Feb 7 15:27:24 2001 Received: (from tlambert@localhost) by usr08.primenet.com (8.8.5/8.8.5) id PAA26462; Wed, 7 Feb 2001 15:32:28 -0700 (MST) From: Terry Lambert Message-Id: <200102072232.PAA26462@usr08.primenet.com> Subject: Re: xucred introduction To: dillon@earth.backplane.com (Matt Dillon) Date: Wed, 7 Feb 2001 22:32:28 +0000 (GMT) Cc: julian@elischer.org (Julian Elischer), phk@critter.freebsd.dk (Poul-Henning Kamp), green@FreeBSD.ORG (Brian F. Feldman), arch@FreeBSD.ORG In-Reply-To: <200102071923.f17JNlX91394@earth.backplane.com> from "Matt Dillon" at Feb 07, 2001 11:23:47 AM X-Mailer: ELM [version 2.5 PL2] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > :this brings up whether we should have 'rules' for kernel structures in general.. > > I'd have to say no. It's too easy for this sort of thing to get > completely out of control. Pretty soon you end up with things like "The VAX Calling Standard", which leads to nasty things like clustering, transparent process migration, autonatic load balancing, software fault tolerance, automatic failover, and all those things we'd rather not think matter to anyone unless they are running a server OS... PS: My vote is to put the mutex first, not export it to user space, and then put the version number. I'd keep the version number even if it weren't a user-space/kernel-space interface, since you never know when it will be useful to deal with passing a structure between a new kernel and an old driver/module, or vice versa... PPS: User-to-kernel writes that change contents should hold the mutex in the kernel, in the API. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message