Add an option "EXTRA_VNODES" to cause an extra number of vnode structures

to be allocated at boot time.  This is an expensive option, as they
consume physical ram and are not pageable etc.  In certain situations,
this kind of option is quite useful, especially for news servers that
access a large number of directories at random and torture the name cache.
Defining 5000 or 10000 extra vnodes should cut down the amount of vnode
recycling somewhat, which should allow better name and directory caching
etc.

This is a "your mileage may vary" option, with no real indication of
what works best for your machine except trial and error.  Too many will
cost you ram that you could otherwise use for disk buffers etc.

This is based on something John Dyson mentioned to me a while ago.

3 files changed, 20 insertions, 4 deletions

diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index 5208535..35ce831 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -2,7 +2,7 @@
 # LINT -- config file for checking all the sources, tries to pull in
 #	as much of the source tree as it can.
 #
-#	$Id: LINT,v 1.258 1996/05/13 04:38:10 nate Exp $
+#	$Id: LINT,v 1.259 1996/05/17 09:42:46 jkh Exp $
 #
 # NB: You probably don't want to try running a kernel built from this
 # file.  Instead, you should start from GENERIC, and add options from
@@ -44,6 +44,16 @@ options		CHILD_MAX=128
 options		OPEN_MAX=128
 
 #
+# Under some circumstances it is useful to have an extra number of
+# vnode data structures allocated at boot time.  In particular,
+# usenet news servers can benefit if there are enough vnodes to
+# cache the busiest newsgroup and overview directories.  Beware that
+# this is an expensive option, it consumes physical non-pageable ram.
+# A busy news server may benefit from 10,000 extra vnodes or so.
+#
+options		EXTRA_VNODES=1
+
+#
 # A math emulator is mandatory if you wish to run on hardware which
 # does not have a floating-point processor.  Pick either the original,
 # bogus (but freely-distributable) math emulator, or a much more
@@ -258,7 +268,7 @@ options		PORTAL			#Portal filesystem
 options		PROCFS			#Process filesystem
 options		UMAPFS			#UID map filesystem
 options		UNION			#Union filesystem
-# THis DEVFS is experimental but seems to work
+# This DEVFS is experimental but seems to work
 options		DEVFS			#devices filesystem
 
 # Make space in the kernel for a MFS root filesystem.  Define to the number
diff --git a/sys/conf/options b/sys/conf/options
index 47fede9..436932a 100644
--- a/sys/conf/options
+++ b/sys/conf/options
@@ -1,4 +1,4 @@
-#	$Id: options,v 1.11 1996/05/05 02:26:57 pst Exp $
+#	$Id: options,v 1.12 1996/05/11 04:39:37 bde Exp $
 
 # Option name	filename
 
@@ -29,6 +29,7 @@ SYSVMSG		opt_sysvipc.h
 UCONSOLE
 
 # Options used only in param.c.
+EXTRAVNODES	opt_param.h
 NMBCLUSTERS	opt_param.h
 SHMMAXPGS	opt_param.h
 SHMMAX		opt_param.h
diff --git a/sys/conf/param.c b/sys/conf/param.c
index f86e749..92c06c1 100644
--- a/sys/conf/param.c
+++ b/sys/conf/param.c
@@ -36,7 +36,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)param.c	8.3 (Berkeley) 8/20/94
- * $Id: param.c,v 1.18 1996/05/02 14:19:18 phk Exp $
+ * $Id: param.c,v 1.19 1996/05/10 19:28:32 wollman Exp $
  */
 
 #include "opt_sysvipc.h"
@@ -89,6 +89,11 @@ int	maxfiles = NPROC*2;			/* system wide open files limit */
 int	maxfilesperproc = NPROC*2;		/* per-process open files limit */
 int	ncallout = 16 + NPROC;			/* maximum # of timer events */
 
+#ifndef EXTRAVNODES
+#define EXTRAVNODES 0
+#endif
+int	extravnodes = EXTRAVNODES;		/* spare vnodes to allocate */
+
 /* maximum # of mbuf clusters */
 #ifndef NMBCLUSTERS
 #define	NMBCLUSTERS (512 + MAXUSERS * 16)