xref: /original-bsd/sys/sys/param.h (revision ab9556f9)
1 /*-
2  * Copyright (c) 1982, 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  * %sccs.include.redist.c%
11  *
12  *	@(#)param.h	8.3 (Berkeley) 04/04/95
13  */
14 
15 #define	BSD	199506		/* System version (year & month). */
16 #define BSD4_3	1
17 #define BSD4_4	1
18 
19 #ifndef NULL
20 #define	NULL	0
21 #endif
22 
23 #ifndef LOCORE
24 #include <sys/types.h>
25 #endif
26 
27 /*
28  * Machine-independent constants (some used in following include files).
29  * Redefined constants are from POSIX 1003.1 limits file.
30  *
31  * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
32  * MAXLOGNAME should be >= UT_NAMESIZE (see <utmp.h>)
33  */
34 #include <sys/syslimits.h>
35 
36 #define	MAXCOMLEN	16		/* max command name remembered */
37 #define	MAXINTERP	32		/* max interpreter file name length */
38 #define	MAXLOGNAME	12		/* max login name length */
39 #define	MAXUPRC		CHILD_MAX	/* max simultaneous processes */
40 #define	NCARGS		ARG_MAX		/* max bytes for an exec function */
41 #define	NGROUPS		NGROUPS_MAX	/* max number groups */
42 #define	NOFILE		OPEN_MAX	/* max open files per process */
43 #define	NOGROUP		65535		/* marker for empty group set member */
44 #define MAXHOSTNAMELEN	256		/* max hostname size */
45 
46 /* More types and definitions used throughout the kernel. */
47 #ifdef KERNEL
48 #include <sys/cdefs.h>
49 #include <sys/errno.h>
50 #include <sys/time.h>
51 #include <sys/resource.h>
52 #include <sys/ucred.h>
53 #include <sys/uio.h>
54 #endif
55 
56 /* Signals. */
57 #include <sys/signal.h>
58 
59 /* Machine type dependent parameters. */
60 #include <machine/param.h>
61 #include <machine/limits.h>
62 
63 /*
64  * Priorities.  Note that with 32 run queues, differences less than 4 are
65  * insignificant.
66  */
67 #define	PSWP	0
68 #define	PVM	4
69 #define	PINOD	8
70 #define	PRIBIO	16
71 #define	PVFS	20
72 #define	PZERO	22		/* No longer magic, shouldn't be here.  XXX */
73 #define	PSOCK	24
74 #define	PWAIT	32
75 #define	PLOCK	36
76 #define	PPAUSE	40
77 #define	PUSER	50
78 #define	MAXPRI	127		/* Priorities range from 0 through MAXPRI. */
79 
80 #define	PRIMASK	0x0ff
81 #define	PCATCH	0x100		/* OR'd with pri for tsleep to check signals */
82 
83 #define	NZERO	0		/* default "nice" */
84 
85 #define	NBPW	sizeof(int)	/* number of bytes per word (integer) */
86 
87 #define	CMASK	022		/* default file mask: S_IWGRP|S_IWOTH */
88 #define	NODEV	(dev_t)(-1)	/* non-existent device */
89 
90 /*
91  * Clustering of hardware pages on machines with ridiculously small
92  * page sizes is done here.  The paging subsystem deals with units of
93  * CLSIZE pte's describing NBPG (from machine/machparam.h) pages each.
94  */
95 #define	CLBYTES		(CLSIZE*NBPG)
96 #define	CLOFSET		(CLSIZE*NBPG-1)	/* for clusters, like PGOFSET */
97 #define	claligned(x)	((((int)(x))&CLOFSET)==0)
98 #define	CLOFF		CLOFSET
99 #define	CLSHIFT		(PGSHIFT+CLSIZELOG2)
100 
101 #if CLSIZE==1
102 #define	clbase(i)	(i)
103 #define	clrnd(i)	(i)
104 #else
105 /* Give the base virtual address (first of CLSIZE). */
106 #define	clbase(i)	((i) &~ (CLSIZE-1))
107 /* Round a number of clicks up to a whole cluster. */
108 #define	clrnd(i)	(((i) + (CLSIZE-1)) &~ (CLSIZE-1))
109 #endif
110 
111 #define	CBLOCK	64		/* Clist block size, must be a power of 2. */
112 #define CBQSIZE	(CBLOCK/NBBY)	/* Quote bytes/cblock - can do better. */
113 				/* Data chars/clist. */
114 #define	CBSIZE	(CBLOCK - sizeof(struct cblock *) - CBQSIZE)
115 #define	CROUND	(CBLOCK - 1)	/* Clist rounding. */
116 
117 /*
118  * File system parameters and macros.
119  *
120  * The file system is made out of blocks of at most MAXBSIZE units, with
121  * smaller units (fragments) only in the last direct block.  MAXBSIZE
122  * primarily determines the size of buffers in the buffer pool.  It may be
123  * made larger without any effect on existing file systems; however making
124  * it smaller make make some file systems unmountable.
125  */
126 #define	MAXBSIZE	MAXPHYS
127 #define MAXFRAG 	8
128 
129 /*
130  * MAXPATHLEN defines the longest permissable path length after expanding
131  * symbolic links. It is used to allocate a temporary buffer from the buffer
132  * pool in which to do the name expansion, hence should be a power of two,
133  * and must be less than or equal to MAXBSIZE.  MAXSYMLINKS defines the
134  * maximum number of symbolic links that may be expanded in a path name.
135  * It should be set high enough to allow all legitimate uses, but halt
136  * infinite loops reasonably quickly.
137  */
138 #define	MAXPATHLEN	PATH_MAX
139 #define MAXSYMLINKS	8
140 
141 /* Bit map related macros. */
142 #define	setbit(a,i)	((a)[(i)/NBBY] |= 1<<((i)%NBBY))
143 #define	clrbit(a,i)	((a)[(i)/NBBY] &= ~(1<<((i)%NBBY)))
144 #define	isset(a,i)	((a)[(i)/NBBY] & (1<<((i)%NBBY)))
145 #define	isclr(a,i)	(((a)[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
146 
147 /* Macros for counting and rounding. */
148 #ifndef howmany
149 #define	howmany(x, y)	(((x)+((y)-1))/(y))
150 #endif
151 #define	roundup(x, y)	((((x)+((y)-1))/(y))*(y))
152 #define powerof2(x)	((((x)-1)&(x))==0)
153 
154 /* Macros for min/max. */
155 #ifndef KERNEL
156 #define	MIN(a,b) (((a)<(b))?(a):(b))
157 #define	MAX(a,b) (((a)>(b))?(a):(b))
158 #endif
159 
160 /*
161  * Constants for setting the parameters of the kernel memory allocator.
162  *
163  * 2 ** MINBUCKET is the smallest unit of memory that will be
164  * allocated. It must be at least large enough to hold a pointer.
165  *
166  * Units of memory less or equal to MAXALLOCSAVE will permanently
167  * allocate physical memory; requests for these size pieces of
168  * memory are quite fast. Allocations greater than MAXALLOCSAVE must
169  * always allocate and free physical memory; requests for these
170  * size allocations should be done infrequently as they will be slow.
171  *
172  * Constraints: CLBYTES <= MAXALLOCSAVE <= 2 ** (MINBUCKET + 14), and
173  * MAXALLOCSIZE must be a power of two.
174  */
175 #define MINBUCKET	4		/* 4 => min allocation of 16 bytes */
176 #define MAXALLOCSAVE	(2 * CLBYTES)
177 
178 /*
179  * Scale factor for scaled integers used to count %cpu time and load avgs.
180  *
181  * The number of CPU `tick's that map to a unique `%age' can be expressed
182  * by the formula (1 / (2 ^ (FSHIFT - 11))).  The maximum load average that
183  * can be calculated (assuming 32 bits) can be closely approximated using
184  * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
185  *
186  * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
187  * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
188  */
189 #define	FSHIFT	11		/* bits to right of fixed binary point */
190 #define FSCALE	(1<<FSHIFT)
191