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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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 500001 /* 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 */
78 /* More types and definitions used throughout the kernel. */
80 #include <sys/cdefs.h>
81 #include <sys/errno.h>
90 #include <sys/signal.h>
93 /* Machine type dependent parameters. */
94 #include <machine/param.h>
96 #include <machine/limits.h>
100 * Priorities. Note that with 32 run queues, differences less than 4 are
108 #define PZERO 22 /* No longer magic, shouldn't be here. XXX */
115 #define MAXPRI 127 /* Priorities range from 0 through MAXPRI. */
117 #define PRIMASK 0x0ff
118 #define PCATCH 0x100 /* OR'd with pri for tsleep to check signals */
120 #define NZERO 0 /* default "nice" */
122 #define NBPW sizeof(int) /* number of bytes per word (integer) */
124 #define CMASK 022 /* default file mask: S_IWGRP|S_IWOTH */
126 #define NODEV (dev_t)(-1) /* non-existent device */
127 #define NOUDEV (udev_t)(-1) /* non-existent device */
128 #define NOMAJ 256 /* non-existent device */
130 #define NODEV (dev_t)(-1) /* non-existent device */
134 * Clustering of hardware pages on machines with ridiculously small
135 * page sizes is done here. The paging subsystem deals with units of
136 * CLSIZE pte's describing PAGE_SIZE (from machine/machparam.h) pages each.
139 #define CLBYTES (CLSIZE*PAGE_SIZE)
142 #define CBLOCK 128 /* Clist block size, must be a power of 2. */
143 #define CBQSIZE (CBLOCK/NBBY) /* Quote bytes/cblock - can do better. */
144 /* Data chars/clist. */
145 #define CBSIZE (CBLOCK - sizeof(struct cblock *) - CBQSIZE)
146 #define CROUND (CBLOCK - 1) /* Clist rounding. */
149 * File system parameters and macros.
151 * MAXBSIZE - Filesystems are made out of blocks of at most MAXBSIZE bytes
152 * per block. MAXBSIZE may be made larger without effecting
153 * any existing filesystems as long as it does not exceed MAXPHYS,
154 * and may be made smaller at the risk of not being able to use
155 * filesystems which require a block size exceeding MAXBSIZE.
157 * BKVASIZE - Nominal buffer space per buffer, in bytes. BKVASIZE is the
158 * minimum KVM memory reservation the kernel is willing to make.
159 * Filesystems can of course request smaller chunks. Actual
160 * backing memory uses a chunk size of a page (PAGE_SIZE).
162 * If you make BKVASIZE too small you risk seriously fragmenting
163 * the buffer KVM map which may slow things down a bit. If you
164 * make it too big the kernel will not be able to optimally use
165 * the KVM memory reserved for the buffer cache and will wind
166 * up with too-few buffers.
168 * The default is 16384, roughly 2x the block size used by a
169 * normal UFS filesystem.
171 #define MAXBSIZE 65536 /* must be power of 2 */
172 #define BKVASIZE 16384 /* must be power of 2 */
173 #define BKVAMASK (BKVASIZE-1)
177 * MAXPATHLEN defines the longest permissible path length after expanding
178 * symbolic links. It is used to allocate a temporary buffer from the buffer
179 * pool in which to do the name expansion, hence should be a power of two,
180 * and must be less than or equal to MAXBSIZE. MAXSYMLINKS defines the
181 * maximum number of symbolic links that may be expanded in a path name.
182 * It should be set high enough to allow all legitimate uses, but halt
183 * infinite loops reasonably quickly.
185 #define MAXPATHLEN PATH_MAX
186 #define MAXSYMLINKS 32
188 /* Bit map related macros. */
189 #define setbit(a,i) ((a)[(i)/NBBY] |= 1<<((i)%NBBY))
190 #define clrbit(a,i) ((a)[(i)/NBBY] &= ~(1<<((i)%NBBY)))
191 #define isset(a,i) ((a)[(i)/NBBY] & (1<<((i)%NBBY)))
192 #define isclr(a,i) (((a)[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
194 /* Macros for counting and rounding. */
196 #define howmany(x, y) (((x)+((y)-1))/(y))
198 #define rounddown(x, y) (((x)/(y))*(y))
199 #define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */
200 #define roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
201 #define powerof2(x) ((((x)-1)&(x))==0)
203 /* Macros for min/max. */
205 #define MIN(a,b) (((a)<(b))?(a):(b))
206 #define MAX(a,b) (((a)>(b))?(a):(b))
210 * Constants for setting the parameters of the kernel memory allocator.
212 * 2 ** MINBUCKET is the smallest unit of memory that will be
213 * allocated. It must be at least large enough to hold a pointer.
215 * Units of memory less or equal to MAXALLOCSAVE will permanently
216 * allocate physical memory; requests for these size pieces of
217 * memory are quite fast. Allocations greater than MAXALLOCSAVE must
218 * always allocate and free physical memory; requests for these
219 * size allocations should be done infrequently as they will be slow.
221 * Constraints: PAGE_SIZE <= MAXALLOCSAVE <= 2 ** (MINBUCKET + 14), and
222 * MAXALLOCSIZE must be a power of two.
224 #if defined(__alpha__)
225 #define MINBUCKET 5 /* 5 => min allocation of 32 bytes */
227 #define MINBUCKET 4 /* 4 => min allocation of 16 bytes */
229 #define MAXALLOCSAVE (2 * PAGE_SIZE)
232 * Scale factor for scaled integers used to count %cpu time and load avgs.
234 * The number of CPU `tick's that map to a unique `%age' can be expressed
235 * by the formula (1 / (2 ^ (FSHIFT - 11))). The maximum load average that
236 * can be calculated (assuming 32 bits) can be closely approximated using
237 * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
239 * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
240 * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
242 #define FSHIFT 11 /* bits to right of fixed binary point */
243 #define FSCALE (1<<FSHIFT)
245 #define dbtoc(db) /* calculates devblks to pages */ \
246 ((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
248 #define ctodb(db) /* calculates pages to devblks */ \
249 ((db) << (PAGE_SHIFT - DEV_BSHIFT))
253 * Make this available for most of the kernel. There were too many
254 * things that included sys/systm.h just for panic().
257 void panic __P((const char *, ...)) __dead2 __printflike(1, 2);
260 #endif /* _SYS_PARAM_H_ */