From owner-freebsd-questions@FreeBSD.ORG Thu Jan 17 19:52:13 2008 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5875316A507; Thu, 17 Jan 2008 19:52:13 +0000 (UTC) (envelope-from rmacklem@uoguelph.ca) Received: from ccshst09.cs.uoguelph.ca (ccshst09.cs.uoguelph.ca [131.104.94.206]) by mx1.freebsd.org (Postfix) with ESMTP id 2F08C13C474; Thu, 17 Jan 2008 19:52:13 +0000 (UTC) (envelope-from rmacklem@uoguelph.ca) Received: from muncher.cs.uoguelph.ca (muncher.cs.uoguelph.ca [131.104.91.102]) by ccshst09.cs.uoguelph.ca (8.13.1/8.13.1) with ESMTP id m0HGZofS012317; Thu, 17 Jan 2008 11:35:50 -0500 Received: from localhost (rmacklem@localhost) by muncher.cs.uoguelph.ca (8.11.7p3+Sun/8.11.6) with ESMTP id m0HGcwT22995; Thu, 17 Jan 2008 11:38:58 -0500 (EST) X-Authentication-Warning: muncher.cs.uoguelph.ca: rmacklem owned process doing -bs Date: Thu, 17 Jan 2008 11:38:58 -0500 (EST) From: Rick Macklem X-X-Sender: rmacklem@muncher.cs.uoguelph.ca To: Robert Watson In-Reply-To: <20080116203521.K15541@fledge.watson.org> Message-ID: References: <18CC5A4A2AC36D7FF57615EE@ganymede.hub.org> <478AF6BC.8050604@highperformance.net> <20080114142124.Y55696@fledge.watson.org> <876FB8E38251C27B14CCCA29@atlantis.pc.cs.cmu.edu> <20080116203521.K15541@fledge.watson.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Scanned-By: MIMEDefang 2.63 on 131.104.94.206 X-Mailman-Approved-At: Thu, 17 Jan 2008 21:02:13 +0000 Cc: rra@stanford.edu, port-freebsd@openafs.org, freebsd-fs@freebsd.org, matt@linuxbox.com, freebsd-afs@freebsd.org, "Jason C. Wells" , openafs-devel@openafs.org, freebsd-questions@freebsd.org, Jeffrey Hutzelman Subject: VFS KPI was Re: [OpenAFS-devel] Re: AFS ... or equivalent ... X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 17 Jan 2008 19:52:13 -0000 On Wed, 16 Jan 2008, Robert Watson wrote: [good stuff snipped] > > Right now we maintain a relatively stable VM/VFS KPI withing a major release > (i.e, FreeBSD 6.0 -> 6.1 -> 6.2 -> 6.3), but see fairly significant changes > between major releases (5.x -> 6.x -> 7.x, etc). I expect to see further > changes in VFS for 8.x (and some of the locking-related ones have already > started going in). > This is loosely related to both the OpenAFS thread and the Mac OS X ZFS port thread, so I thought I'd ask... Has anyone considered trying to bring the FreeBSD VFS KPI (and others, for that matter) closed to the Darwin/Mac OS X ones? The Apple folks made quite dramatic changes to their VFS when going from Panther (very FreeBSD like) to Tiger, but seemed to have stabilized, at least for Leopard. It just seems that using the Mac OS X KPIs might leverage some work being done on both sides? (I don't know if there is an OpenAFS port to Mac OS X or interest in one, but I would think there would be a use for one, if it existed?) Although I'm far from an expert on the Mac OS X VFS (when I ported to it, I just cribbed the code and it worked:-), it seems that they pretty well got rid of the concept of a vnode-lock. If the underlying file system isn't SMP safe, it can put a lock on the subsystem at the VFS call. (I think it optionally does a global lock or a uses an smp lock in the vnode, but don't quote me on this. My code currently runs with the thread-safe flag false in the vfs_conf structure entry, which enables the automagic locking.) Just a thought, rick