From owner-freebsd-hackers Wed Jan 6 14:46:08 1999 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id OAA17473 for freebsd-hackers-outgoing; Wed, 6 Jan 1999 14:46:08 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from gatekeeper.tsc.tdk.com (gatekeeper.tsc.tdk.com [207.113.159.21]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id OAA17467 for ; Wed, 6 Jan 1999 14:46:07 -0800 (PST) (envelope-from gdonl@tsc.tdk.com) Received: from sunrise.gv.tsc.tdk.com (root@sunrise.gv.tsc.tdk.com [192.168.241.191]) by gatekeeper.tsc.tdk.com (8.8.8/8.8.8) with ESMTP id OAA24575; Wed, 6 Jan 1999 14:44:49 -0800 (PST) (envelope-from gdonl@tsc.tdk.com) Received: from salsa.gv.tsc.tdk.com (salsa.gv.tsc.tdk.com [192.168.241.194]) by sunrise.gv.tsc.tdk.com (8.8.5/8.8.5) with ESMTP id OAA19290; Wed, 6 Jan 1999 14:44:48 -0800 (PST) Received: (from gdonl@localhost) by salsa.gv.tsc.tdk.com (8.8.5/8.8.5) id OAA01922; Wed, 6 Jan 1999 14:44:47 -0800 (PST) From: Don Lewis Message-Id: <199901062244.OAA01922@salsa.gv.tsc.tdk.com> Date: Wed, 6 Jan 1999 14:44:47 -0800 In-Reply-To: "John S. Dyson" "Re: questions/problems with vm_fault() in Stable" (Jan 5, 9:55pm) X-Mailer: Mail User's Shell (7.2.6 alpha(3) 7/19/95) To: dyson@iquest.net, tlambert@primenet.com (Terry Lambert) Subject: Re: questions/problems with vm_fault() in Stable Cc: dillon@apollo.backplane.com, pfgiffun@bachue.usc.unal.edu.co, freebsd-hackers@FreeBSD.ORG Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Jan 5, 9:55pm, "John S. Dyson" wrote: } Subject: Re: questions/problems with vm_fault() in Stable } Any of the problems with the existing VFS/VM scheme have been with the } intricacies of dealing with VFS special cases, and dealing with the } I/O abstraction of buffers as a cache. Forget "files" and think } "blobs of memory." Once the notion of file is forgotten, then shadowing, } invalidation and aliasing of memory become very obvious... One complication that comes to mind is /dev/vn*. There's a blob of memory associated with the file that's attached to this device. If you create a filesystem on this device and mount it, then each of the files in that filesystem will also have an associated blob of memory and these memory blobs are subsets of the big blob. Of course you could do something really crazy and use something like ccd to stripe a couple of /dev/vn* devices together and use the result as a filesystem ... Maybe the thing to do is to turn all the filesystems into stacking layers, including ffs. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message