xref: /freebsd/sys/kern/subr_param.c (revision 6adf353a56a161443406b44a45d00c688ca7b857)
1 /*
2  * Copyright (c) 1980, 1986, 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)param.c	8.3 (Berkeley) 8/20/94
39  * $FreeBSD$
40  */
41 
42 #include "opt_param.h"
43 #include "opt_maxusers.h"
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/kernel.h>
48 
49 /*
50  * System parameter formulae.
51  */
52 
53 #ifndef HZ
54 #define	HZ 100
55 #endif
56 #define	NPROC (20 + 16 * maxusers)
57 #ifndef NBUF
58 #define NBUF 0
59 #endif
60 #ifndef MAXFILES
61 #define	MAXFILES (maxproc * 2)
62 #endif
63 
64 int	hz;
65 int	tick;
66 int	tickadj;			 /* can adjust 30ms in 60s */
67 int	maxusers;			/* base tunable */
68 int	maxproc;			/* maximum # of processes */
69 int	maxprocperuid;			/* max # of procs per user */
70 int	maxfiles;			/* sys. wide open files limit */
71 int	maxfilesperproc;		/* per-proc open files limit */
72 int	ncallout;			/* maximum # of timer events */
73 int	nbuf;
74 int	nswbuf;
75 
76 /*
77  * These have to be allocated somewhere; allocating
78  * them here forces loader errors if this file is omitted
79  * (if they've been externed everywhere else; hah!).
80  */
81 struct	buf *swbuf;
82 
83 /*
84  * Total number of shared mutexes to protect all lockmgr locks.
85  */
86 #ifndef	LOCKMUTEX
87 #define LOCKMUTEX	10
88 #endif
89 int	lock_nmtx = LOCKMUTEX;
90 
91 /*
92  * Boot time overrides
93  */
94 void
95 init_param(void)
96 {
97 
98 	/* Base parameters */
99 	maxusers = MAXUSERS;
100 	TUNABLE_INT_FETCH("kern.maxusers", &maxusers);
101 	hz = HZ;
102 	TUNABLE_INT_FETCH("kern.hz", &hz);
103 	tick = 1000000 / hz;
104 	tickadj = howmany(30000, 60 * hz);	/* can adjust 30ms in 60s */
105 
106 	/* The following can be overridden after boot via sysctl */
107 	maxproc = NPROC;
108 	TUNABLE_INT_FETCH("kern.maxproc", &maxproc);
109 	maxfiles = MAXFILES;
110 	TUNABLE_INT_FETCH("kern.maxfiles", &maxfiles);
111 	maxprocperuid = maxproc - 1;
112 	maxfilesperproc = maxfiles;
113 
114 	/* Cannot be changed after boot */
115 	nbuf = NBUF;
116 	TUNABLE_INT_FETCH("kern.nbuf", &nbuf);
117 	ncallout = 16 + maxproc + maxfiles;
118 	TUNABLE_INT_FETCH("kern.ncallout", &ncallout);
119 }
120