Date: Thu, 16 May 1996 10:23:22 +0200 (MET DST) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: toor@dyson.iquest.net (John S. Dyson) Cc: alc@cs.rice.edu, questions@FreeBSD.org Subject: Re: Size of the Virtual Memory Page Message-ID: <199605160823.KAA04249@labinfo.iet.unipi.it> In-Reply-To: <199605160522.AAA00186@dyson.iquest.net> from "John S. Dyson" at May 16, 96 00:22:34 am
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[haven't seen yet the previous messages, but I assume the subject is using larger units of allocation for "pages"] > > 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 my curiosity is how/why do you use 512 byte-blocks: just to leave it open the use of different page sizes (and 512*8=4K, so a dirty x86 page just has a mark of 0xff) ? Luigi ==================================================================== Luigi Rizzo Dip. di Ingegneria dell'Informazione email: luigi@iet.unipi.it Universita' di Pisa tel: +39-50-568533 via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 http://www.iet.unipi.it/~luigi/ ====================================================================
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