[src/trunk]: src/share/man/man4 Clarify NKMEMCLUSTERS and NMBCLUSTERS.

[thorpej <thorpej%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/95339d1c74f3
branches:  trunk
changeset: 467317:95339d1c74f3
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Tue Mar 23 00:33:32 1999 +0000

description:
Clarify NKMEMCLUSTERS and NMBCLUSTERS.

diffstat:

 share/man/man4/options.4 |  24 ++++++++++++++++--------
 1 files changed, 16 insertions(+), 8 deletions(-)

diffs (47 lines):

diff -r 4dd856fadde5 -r 95339d1c74f3 share/man/man4/options.4
--- a/share/man/man4/options.4  Tue Mar 23 00:32:27 1999 +0000
+++ b/share/man/man4/options.4  Tue Mar 23 00:33:32 1999 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: options.4,v 1.72 1999/03/16 01:19:17 garbled Exp $
+.\"    $NetBSD: options.4,v 1.73 1999/03/23 00:33:32 thorpej Exp $
 .\"
 .\" Copyright (c) 1996
 .\"    Perry E. Metzger.  All rights reserved.
@@ -1132,12 +1132,14 @@
 -- you cannot actually run without this
 .Dq option .
 .It Cd options NMBCLUSTERS=value
-Size of kernel mbuf cluster map,
+The number of mbuf clusters the kernel supports.  Mbuf clusters are
+MCLBYTES in size (usually 2k).  This is used to compute the size of
+the kernel VM map
 .Em mb_map ,
-in CLBYTES-sized logical
-pages.
+which maps mbuf clusters.
 Default on most ports is 256 (512 with
-.Dq options GATEWAY ).
+.Dq options GATEWAY
+).
 See
 .Pa /usr/include/machine/param.h
 for exact default information.
@@ -1145,9 +1147,15 @@
 .Dq mb_map full
 messages.
 .It Cd options NKMEMCLUSTERS=value
-Size of kernel malloc arena in CLBYTES-sized logical pages.
-This area is covered by the kernel submap
-.Em kmem_map .
+Size of kernel VM map
+.Em kmem_map ,
+in CLBYTES-sized chunks (the VM page size; this value may be read
+from the
+.Xr sysctl 8
+variable
+.Em hw.pagesize
+).
+This VM map is used to map the kernel malloc arena.
 See
 .Pa /usr/include/machine/param.h
 for the default value, which is port specific.