Date: Fri, 17 May 1996 17:49:13 -0500 (EST) From: "John S. Dyson" <toor@dyson.iquest.net> To: terry@lambert.org (Terry Lambert) Cc: alc@cs.rice.edu, questions@freebsd.org Subject: Re: Size of the Virtual Memory Page Message-ID: <199605172249.RAA03013@dyson.iquest.net> In-Reply-To: <199605172118.OAA20724@phaeton.artisoft.com> from "Terry Lambert" at May 17, 96 02:18:20 pm
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> > 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. > NO QUESTION about that. In fact, I would plan to consult with anyone doing ports to other architectures before making changes of that kind. I really don't forsee doing it for at least six months anyway. John
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