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.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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.
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * @(#)param.h 8.3 (Berkeley) 4/4/95
45 #define BSD 199506 /* System version (year & month). */
48 #undef __FreeBSD_version
49 #define __FreeBSD_version 500018 /* Master, propagated to newvers */
56 #include <sys/types.h>
60 * Machine-independent constants (some used in following include files).
61 * Redefined constants are from POSIX 1003.1 limits file.
63 * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
64 * MAXLOGNAME should be == UT_NAMESIZE+1 (see <utmp.h>)
66 #include <sys/syslimits.h>
68 #define MAXCOMLEN 16 /* max command name remembered */
69 #define MAXINTERP 32 /* max interpreter file name length */
70 #define MAXLOGNAME 17 /* max login name length (incl. NUL) */
71 #define MAXUPRC CHILD_MAX /* max simultaneous processes */
72 #define NCARGS ARG_MAX /* max bytes for an exec function */
73 #define NGROUPS NGROUPS_MAX /* max number groups */
74 #define NOFILE OPEN_MAX /* max open files per process */
75 #define NOGROUP 65535 /* marker for empty group set member */
76 #define MAXHOSTNAMELEN 256 /* max hostname size */
77 #define SPECNAMELEN 15 /* max length of devicename */
79 /* More types and definitions used throughout the kernel. */
81 #include <sys/cdefs.h>
82 #include <sys/errno.h>
84 #include <sys/priority.h>
92 #include <sys/signal.h>
95 /* Machine type dependent parameters. */
96 #include <machine/param.h>
98 #include <machine/limits.h>
101 #define PRIMASK 0x0ff
102 #define PCATCH 0x100 /* OR'd with pri for tsleep to check signals */
103 #define PDROP 0x200 /* OR'd with pri to stop re-entry of interlock mutex */
105 #define NZERO 0 /* default "nice" */
107 #define NBPW sizeof(int) /* number of bytes per word (integer) */
109 #define CMASK 022 /* default file mask: S_IWGRP|S_IWOTH */
111 #define NODEV (dev_t)(-1) /* non-existent device */
112 #define NOUDEV (udev_t)(-1) /* non-existent device */
113 #define NOMAJ 256 /* non-existent device */
115 #define NODEV (dev_t)(-1) /* non-existent device */
118 #define CBLOCK 128 /* Clist block size, must be a power of 2. */
119 #define CBQSIZE (CBLOCK/NBBY) /* Quote bytes/cblock - can do better. */
120 /* Data chars/clist. */
121 #define CBSIZE (CBLOCK - sizeof(struct cblock *) - CBQSIZE)
122 #define CROUND (CBLOCK - 1) /* Clist rounding. */
125 * File system parameters and macros.
127 * MAXBSIZE - Filesystems are made out of blocks of at most MAXBSIZE bytes
128 * per block. MAXBSIZE may be made larger without effecting
129 * any existing filesystems as long as it does not exceed MAXPHYS,
130 * and may be made smaller at the risk of not being able to use
131 * filesystems which require a block size exceeding MAXBSIZE.
133 * BKVASIZE - Nominal buffer space per buffer, in bytes. BKVASIZE is the
134 * minimum KVM memory reservation the kernel is willing to make.
135 * Filesystems can of course request smaller chunks. Actual
136 * backing memory uses a chunk size of a page (PAGE_SIZE).
138 * If you make BKVASIZE too small you risk seriously fragmenting
139 * the buffer KVM map which may slow things down a bit. If you
140 * make it too big the kernel will not be able to optimally use
141 * the KVM memory reserved for the buffer cache and will wind
142 * up with too-few buffers.
144 * The default is 16384, roughly 2x the block size used by a
145 * normal UFS filesystem.
147 #define MAXBSIZE 65536 /* must be power of 2 */
148 #define BKVASIZE 16384 /* must be power of 2 */
149 #define BKVAMASK (BKVASIZE-1)
153 * MAXPATHLEN defines the longest permissible path length after expanding
154 * symbolic links. It is used to allocate a temporary buffer from the buffer
155 * pool in which to do the name expansion, hence should be a power of two,
156 * and must be less than or equal to MAXBSIZE. MAXSYMLINKS defines the
157 * maximum number of symbolic links that may be expanded in a path name.
158 * It should be set high enough to allow all legitimate uses, but halt
159 * infinite loops reasonably quickly.
161 #define MAXPATHLEN PATH_MAX
162 #define MAXSYMLINKS 32
164 /* Bit map related macros. */
165 #define setbit(a,i) ((a)[(i)/NBBY] |= 1<<((i)%NBBY))
166 #define clrbit(a,i) ((a)[(i)/NBBY] &= ~(1<<((i)%NBBY)))
167 #define isset(a,i) ((a)[(i)/NBBY] & (1<<((i)%NBBY)))
168 #define isclr(a,i) (((a)[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
170 /* Macros for counting and rounding. */
172 #define howmany(x, y) (((x)+((y)-1))/(y))
174 #define rounddown(x, y) (((x)/(y))*(y))
175 #define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */
176 #define roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
177 #define powerof2(x) ((((x)-1)&(x))==0)
179 /* Macros for min/max. */
181 #define MIN(a,b) (((a)<(b))?(a):(b))
182 #define MAX(a,b) (((a)>(b))?(a):(b))
186 * Constants for setting the parameters of the kernel memory allocator.
188 * 2 ** MINBUCKET is the smallest unit of memory that will be
189 * allocated. It must be at least large enough to hold a pointer.
191 * Units of memory less or equal to MAXALLOCSAVE will permanently
192 * allocate physical memory; requests for these size pieces of
193 * memory are quite fast. Allocations greater than MAXALLOCSAVE must
194 * always allocate and free physical memory; requests for these
195 * size allocations should be done infrequently as they will be slow.
197 * Constraints: PAGE_SIZE <= MAXALLOCSAVE <= 2 ** (MINBUCKET + 14), and
198 * MAXALLOCSIZE must be a power of two.
200 #if defined(__alpha__) || defined(__ia64__)
201 #define MINBUCKET 5 /* 5 => min allocation of 32 bytes */
203 #define MINBUCKET 4 /* 4 => min allocation of 16 bytes */
205 #define MAXALLOCSAVE (2 * PAGE_SIZE)
208 * Scale factor for scaled integers used to count %cpu time and load avgs.
210 * The number of CPU `tick's that map to a unique `%age' can be expressed
211 * by the formula (1 / (2 ^ (FSHIFT - 11))). The maximum load average that
212 * can be calculated (assuming 32 bits) can be closely approximated using
213 * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
215 * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
216 * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
218 #define FSHIFT 11 /* bits to right of fixed binary point */
219 #define FSCALE (1<<FSHIFT)
221 #define dbtoc(db) /* calculates devblks to pages */ \
222 ((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
224 #define ctodb(db) /* calculates pages to devblks */ \
225 ((db) << (PAGE_SHIFT - DEV_BSHIFT))
229 * Make this available for most of the kernel. There were too many
230 * things that included sys/systm.h just for panic().
233 void panic __P((const char *, ...)) __dead2 __printflike(1, 2);
235 #endif /* _SYS_PARAM_H_ */