FreeBSD/Linux Kernel Cross Reference
sys/sys/param.h
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 * 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.h 8.3 (Berkeley) 4/4/95
39 * $FreeBSD$
40 */
41
42 #ifndef _SYS_PARAM_H_
43 #define _SYS_PARAM_H_
44
45 #define BSD 199506 /* System version (year & month). */
46 #define BSD4_3 1
47 #define BSD4_4 1
48
49 /*
50 * __FreeBSD_version numbers are documented in the Porter's Handbook.
51 * If you bump the version for any reason, you should update the documentation
52 * there.
53 * Currently this lives here:
54 * doc/en_US.ISO8859-1/books/porters-handbook/book.sgml
55 */
56 #undef __FreeBSD_version
57 #define __FreeBSD_version 492101 /* Master, propagated to newvers */
58
59 #ifndef NULL
60 #define NULL 0
61 #endif
62
63 #ifndef LOCORE
64 #include <sys/types.h>
65 #endif
66
67 /*
68 * Machine-independent constants (some used in following include files).
69 * Redefined constants are from POSIX 1003.1 limits file.
70 *
71 * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
72 * MAXLOGNAME should be == UT_NAMESIZE+1 (see <utmp.h>)
73 */
74 #include <sys/syslimits.h>
75
76 #define MAXCOMLEN 16 /* max command name remembered */
77 #define MAXINTERP 32 /* max interpreter file name length */
78 #define MAXLOGNAME 17 /* max login name length (incl. NUL) */
79 #define MAXUPRC CHILD_MAX /* max simultaneous processes */
80 #define NCARGS ARG_MAX /* max bytes for an exec function */
81 #define NGROUPS NGROUPS_MAX /* max number groups */
82 #define NOFILE OPEN_MAX /* max open files per process */
83 #define NOGROUP 65535 /* marker for empty group set member */
84 #define MAXHOSTNAMELEN 256 /* max hostname size */
85
86 /* More types and definitions used throughout the kernel. */
87 #ifdef _KERNEL
88 #include <sys/cdefs.h>
89 #include <sys/errno.h>
90 #include <sys/time.h>
91
92 #define FALSE 0
93 #define TRUE 1
94 #endif
95
96 #ifndef _KERNEL
97 /* Signals. */
98 #include <sys/signal.h>
99 #endif
100
101 /* Machine type dependent parameters. */
102 #include <machine/param.h>
103 #ifndef _KERNEL
104 #include <machine/limits.h>
105 #endif
106
107 /*
108 * Priorities. Note that with 32 run queues, differences less than 4 are
109 * insignificant.
110 */
111 #define PSWP 0
112 #define PVM 4
113 #define PINOD 8
114 #define PRIBIO 16
115 #define PVFS 20
116 #define PZERO 22 /* No longer magic, shouldn't be here. XXX */
117 #define PSOCK 24
118 #define PWAIT 32
119 #define PCONFIG 32
120 #define PLOCK 36
121 #define PPAUSE 40
122 #define PUSER 50
123 #define MAXPRI 127 /* Priorities range from 0 through MAXPRI. */
124
125 #define PRIMASK 0x0ff
126 #define PCATCH 0x100 /* OR'd with pri for tsleep to check signals */
127
128 #define NZERO 0 /* default "nice" */
129
130 #define NBPW sizeof(int) /* number of bytes per word (integer) */
131
132 #define CMASK 022 /* default file mask: S_IWGRP|S_IWOTH */
133 #ifdef _KERNEL
134 #define NODEV (dev_t)(-1) /* non-existent device */
135 #define NOUDEV (udev_t)(-1) /* non-existent device */
136 #define NOMAJ 256 /* non-existent device */
137 #else
138 #define NODEV (dev_t)(-1) /* non-existent device */
139 #endif
140
141 /*
142 * Clustering of hardware pages on machines with ridiculously small
143 * page sizes is done here. The paging subsystem deals with units of
144 * CLSIZE pte's describing PAGE_SIZE (from machine/machparam.h) pages each.
145 */
146 #if 0
147 #define CLBYTES (CLSIZE*PAGE_SIZE)
148 #endif
149
150 #define CBLOCK 128 /* Clist block size, must be a power of 2. */
151 #define CBQSIZE (CBLOCK/NBBY) /* Quote bytes/cblock - can do better. */
152 /* Data chars/clist. */
153 #define CBSIZE (CBLOCK - sizeof(struct cblock *) - CBQSIZE)
154 #define CROUND (CBLOCK - 1) /* Clist rounding. */
155
156 /*
157 * File system parameters and macros.
158 *
159 * MAXBSIZE - Filesystems are made out of blocks of at most MAXBSIZE bytes
160 * per block. MAXBSIZE may be made larger without effecting
161 * any existing filesystems as long as it does not exceed MAXPHYS,
162 * and may be made smaller at the risk of not being able to use
163 * filesystems which require a block size exceeding MAXBSIZE.
164 *
165 * BKVASIZE - Nominal buffer space per buffer, in bytes. BKVASIZE is the
166 * minimum KVM memory reservation the kernel is willing to make.
167 * Filesystems can of course request smaller chunks. Actual
168 * backing memory uses a chunk size of a page (PAGE_SIZE).
169 *
170 * If you make BKVASIZE too small you risk seriously fragmenting
171 * the buffer KVM map which may slow things down a bit. If you
172 * make it too big the kernel will not be able to optimally use
173 * the KVM memory reserved for the buffer cache and will wind
174 * up with too-few buffers.
175 *
176 * The default is 16384, roughly 2x the block size used by a
177 * normal UFS filesystem.
178 */
179 #define MAXBSIZE 65536 /* must be power of 2 */
180 #define BKVASIZE 16384 /* must be power of 2 */
181 #define BKVAMASK (BKVASIZE-1)
182 #define MAXFRAG 8
183
184 /*
185 * MAXPATHLEN defines the longest permissible path length after expanding
186 * symbolic links. It is used to allocate a temporary buffer from the buffer
187 * pool in which to do the name expansion, hence should be a power of two,
188 * and must be less than or equal to MAXBSIZE. MAXSYMLINKS defines the
189 * maximum number of symbolic links that may be expanded in a path name.
190 * It should be set high enough to allow all legitimate uses, but halt
191 * infinite loops reasonably quickly.
192 */
193 #define MAXPATHLEN PATH_MAX
194 #define MAXSYMLINKS 32
195
196 /* Bit map related macros. */
197 #define setbit(a,i) ((a)[(i)/NBBY] |= 1<<((i)%NBBY))
198 #define clrbit(a,i) ((a)[(i)/NBBY] &= ~(1<<((i)%NBBY)))
199 #define isset(a,i) ((a)[(i)/NBBY] & (1<<((i)%NBBY)))
200 #define isclr(a,i) (((a)[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
201
202 /* Macros for counting and rounding. */
203 #ifndef howmany
204 #define howmany(x, y) (((x)+((y)-1))/(y))
205 #endif
206 #define rounddown(x, y) (((x)/(y))*(y))
207 #define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */
208 #define roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
209 #define powerof2(x) ((((x)-1)&(x))==0)
210
211 /* Macros for min/max. */
212 #ifndef _KERNEL
213 #define MIN(a,b) (((a)<(b))?(a):(b))
214 #define MAX(a,b) (((a)>(b))?(a):(b))
215 #endif
216
217 /*
218 * Constants for setting the parameters of the kernel memory allocator.
219 *
220 * 2 ** MINBUCKET is the smallest unit of memory that will be
221 * allocated. It must be at least large enough to hold a pointer.
222 *
223 * Units of memory less or equal to MAXALLOCSAVE will permanently
224 * allocate physical memory; requests for these size pieces of
225 * memory are quite fast. Allocations greater than MAXALLOCSAVE must
226 * always allocate and free physical memory; requests for these
227 * size allocations should be done infrequently as they will be slow.
228 *
229 * Constraints: PAGE_SIZE <= MAXALLOCSAVE <= 2 ** (MINBUCKET + 14), and
230 * MAXALLOCSIZE must be a power of two.
231 */
232 #if defined(__alpha__)
233 #define MINBUCKET 5 /* 5 => min allocation of 32 bytes */
234 #else
235 #define MINBUCKET 4 /* 4 => min allocation of 16 bytes */
236 #endif
237 #define MAXALLOCSAVE (2 * PAGE_SIZE)
238
239 /*
240 * Scale factor for scaled integers used to count %cpu time and load avgs.
241 *
242 * The number of CPU `tick's that map to a unique `%age' can be expressed
243 * by the formula (1 / (2 ^ (FSHIFT - 11))). The maximum load average that
244 * can be calculated (assuming 32 bits) can be closely approximated using
245 * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
246 *
247 * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
248 * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
249 */
250 #define FSHIFT 11 /* bits to right of fixed binary point */
251 #define FSCALE (1<<FSHIFT)
252
253 #define dbtoc(db) /* calculates devblks to pages */ \
254 ((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
255
256 #define ctodb(db) /* calculates pages to devblks */ \
257 ((db) << (PAGE_SHIFT - DEV_BSHIFT))
258
259
260 /*
261 * Make this available for most of the kernel. There were too many
262 * things that included sys/systm.h just for panic().
263 */
264 #ifdef _KERNEL
265 void panic __P((const char *, ...)) __dead2 __printflike(1, 2);
266 #endif
267
268 #endif /* _SYS_PARAM_H_ */
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