From owner-freebsd-questions Fri May 17 14:22:31 1996 Return-Path: owner-questions Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id OAA20782 for questions-outgoing; Fri, 17 May 1996 14:22:31 -0700 (PDT) Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.211]) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id OAA20758 for ; Fri, 17 May 1996 14:22:26 -0700 (PDT) Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id OAA20724; Fri, 17 May 1996 14:18:21 -0700 From: Terry Lambert Message-Id: <199605172118.OAA20724@phaeton.artisoft.com> Subject: Re: Size of the Virtual Memory Page To: toor@dyson.iquest.net (John S. Dyson) Date: Fri, 17 May 1996 14:18:20 -0700 (MST) Cc: alc@cs.rice.edu, questions@freebsd.org In-Reply-To: <199605160522.AAA00186@dyson.iquest.net> from "John S. Dyson" at May 16, 96 00:22:53 am X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-questions@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > > P.S. Theoretically, you could do the same thing on the x86. John (Dyson), > > have you ever thought of trying this just for grins? Some stuff would likely > > break, but... :-) > > > I have thought about it (in passing.) Actually, it could decrease overhead in > some cases, at the expense of memory. 8/16K pages *might* be interesting. The > VM and vfs_bio system (after my changes) will have problems with bigger than > 16K pages. I am sure that they could be worked around. The limitation > has to do with the bit-mask that I use for valid and dirtyness being in > 512 byte increments. We have 32bits/word, so that means that 16K is kind > of the max (if you ignore long-longs.) Long-longs would bring it up to > 32K. I would guess that 64K might be cool also, but require a few changes. If you do this, *PLEASE* bracket the code with compile-time disablers so I don't have to support 16k pages on the PPC. Thanks. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.