Subject: BUFPAGES, NBUF, and 64K Buffer Size
To: None <tech-kern@NetBSD.ORG>
From: Curt Sampson <>
List: tech-kern
Date: 08/01/1997 12:23:57
On my Sparc IPX, shifting to a 64K buffer size (the virtual size
of each disk buffer) caused problems in machines with more than
about 32 MB of memory, because there wasn't enough address space
in the kernel virtual map to contain all those buffers. Now I
discover I have the same problem on the i386; I'm limited to
nbuf=1388 (a bit over 5 MB) because there's a test to make sure
that kernel buffers don't use up more than 7/10ths of the kernel
VM map.

Do we have a solution to this problem? I'd really like to have
about 2000 buffers on my system, which is only 8 MB of RAM, but is
128 MB of virtual address space.


Curt Sampson	   Info at
Internet Portal Services, Inc.	   Through infinite myst, software reverberates
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