From owner-freebsd-hackers Wed Apr 18 11:53:35 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.86.163]) by hub.freebsd.org (Postfix) with ESMTP id 91CC937B424; Wed, 18 Apr 2001 11:53:30 -0700 (PDT) (envelope-from phk@critter.freebsd.dk) Received: from critter (localhost [127.0.0.1]) by critter.freebsd.dk (8.11.3/8.11.3) with ESMTP id f3IIrIU42364; Wed, 18 Apr 2001 20:53:18 +0200 (CEST) (envelope-from phk@critter.freebsd.dk) To: Matt Dillon Cc: Julian Elischer , Robert Watson , Kirk McKusick , Rik van Riel , freebsd-hackers@FreeBSD.ORG, David Xu Subject: Re: vm balance In-Reply-To: Your message of "Wed, 18 Apr 2001 11:11:19 PDT." <200104181811.f3IIBJp25644@earth.backplane.com> Date: Wed, 18 Apr 2001 20:53:18 +0200 Message-ID: <42362.987619998@critter> From: Poul-Henning Kamp Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In message <200104181811.f3IIBJp25644@earth.backplane.com>, Matt Dillon writes: > Actually, all this talk does imply that VM objects should be independant > of vnodes. Devices may need to mmap (requiring a VM object), but > don't need all the baggage of a vnode. Julian is absolutely correct > there. Well, you have other VM Objects which doesn't map to vnodes: swap backed anonymous objects for instance. > We do need to guarentee locking order, which means that all I/O > operations should be consistent. If a device or vnode is mmap()able, > then all read, write, and truncation(/extention) ops *should* run > through the VM object first: We guarantee that today my mapping the actual hardware and my having all read/writes be synchronouse. I remember at least one other UNIX which didn't make that guarantee. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message