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From: cgd@eden.CS.Berkeley.EDU (Chris G. Demetriou)
Newsgroups: comp.os.386bsd.bugs
Subject: Re: Mixing 4k and 8k filesystems
Date: 19 Nov 93 00:00:53
Organization: Kernel Hackers 'r' Us
Lines: 26
Message-ID: <CGD.93Nov19000053@eden.CS.Berkeley.EDU>
References: <2c7nn4$3g5@cleese.apana.org.au> <35346@ksr.com> <2cc4sd$6s6@u.cc.utah.edu>
NNTP-Posting-Host: eden.cs.berkeley.edu
In-reply-to: terry@cs.weber.edu's message of 17 Nov 1993 03:13:17 GMT
In article <2cc4sd$6s6@u.cc.utah.edu> terry@cs.weber.edu (A Wizard of Earth C) writes:
>NetBSD does not have this problem because they have unified the VM and
>buffer cache (at least on current).
no we don't. we just do 'the standard thing' with buffer cache pages,
that meaning "we allocate a certain number of them, then move them around
depending on where they're needed.
>FreeBSD doesn't have this problem because of the way page reclamation is
>done (at least on current).
actually, they don't have it (from looking at their code and from
reading the mail messages that come over the freebsd mailing lists,
etc.) because they make the kernel memory map large enough that
"fragmentation is not a problem," or at least that's what somebody
(i think davidg) said... given the fact that they reclaim sub-page
buffers, they could make the problem *worse* but for the larger
kmem map.
chris
--
chris g. demetriou cgd@cs.berkeley.edu
smarter than your average clam.