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 * 4. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * @(#)param.h 8.3 (Berkeley) 4/4/95
35 * $FreeBSD: releng/6.3/sys/sys/param.h 174427 2007-12-07 23:22:57Z kmacy $
36 */
37
38 #ifndef _SYS_PARAM_H_
39 #define _SYS_PARAM_H_
40
41 #include <sys/_null.h>
42
43 #define BSD 199506 /* System version (year & month). */
44 #define BSD4_3 1
45 #define BSD4_4 1
46
47 /*
48 * __FreeBSD_version numbers are documented in the Porter's Handbook.
49 * If you bump the version for any reason, you should update the documentation
50 * there.
51 * Currently this lives here:
52 *
53 * doc/en_US.ISO8859-1/books/porters-handbook/book.sgml
54 *
55 * scheme is: <major><two digit minor>Rxx
56 * 'R' is 0 if release branch or x.0-CURRENT before RELENG_*_0
57 * is created, otherwise 1.
58 */
59 #undef __FreeBSD_version
60 #define __FreeBSD_version 603000 /* Master, propagated to newvers */
61
62 #ifndef LOCORE
63 #include <sys/types.h>
64 #endif
65
66 /*
67 * Machine-independent constants (some used in following include files).
68 * Redefined constants are from POSIX 1003.1 limits file.
69 *
70 * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
71 * MAXLOGNAME should be == UT_NAMESIZE+1 (see <utmp.h>)
72 */
73 #include <sys/syslimits.h>
74
75 #define MAXCOMLEN 19 /* max command name remembered */
76 #define MAXINTERP 32 /* max interpreter file name length */
77 #define MAXLOGNAME 17 /* max login name length (incl. NUL) */
78 #define MAXUPRC CHILD_MAX /* max simultaneous processes */
79 #define NCARGS ARG_MAX /* max bytes for an exec function */
80 #define NGROUPS NGROUPS_MAX /* max number groups */
81 #define NOFILE OPEN_MAX /* max open files per process */
82 #define NOGROUP 65535 /* marker for empty group set member */
83 #define MAXHOSTNAMELEN 256 /* max hostname size */
84 #define SPECNAMELEN 63 /* max length of devicename */
85
86 /* More types and definitions used throughout the kernel. */
87 #ifdef _KERNEL
88 #if 0
89 #if (defined(BURN_BRIDGES) || __FreeBSD_version >= 600000) \
90 && defined(OBSOLETE_IN_6)
91 #error "This file contains obsolete code to be removed in 6.0-current"
92 #endif
93 #endif
94 #include <sys/cdefs.h>
95 #include <sys/errno.h>
96 #include <sys/time.h>
97 #include <sys/priority.h>
98
99 #define FALSE 0
100 #define TRUE 1
101 #endif
102
103 #ifndef _KERNEL
104 /* Signals. */
105 #include <sys/signal.h>
106 #endif
107
108 /* Machine type dependent parameters. */
109 #include <machine/param.h>
110 #ifndef _KERNEL
111 #include <sys/limits.h>
112 #endif
113
114 #ifndef _NO_NAMESPACE_POLLUTION
115
116 #ifndef DEV_BSHIFT
117 #define DEV_BSHIFT 9 /* log2(DEV_BSIZE) */
118 #endif
119 #define DEV_BSIZE (1<<DEV_BSHIFT)
120
121 #ifndef BLKDEV_IOSIZE
122 #define BLKDEV_IOSIZE PAGE_SIZE /* default block device I/O size */
123 #endif
124 #ifndef DFLTPHYS
125 #define DFLTPHYS (64 * 1024) /* default max raw I/O transfer size */
126 #endif
127 #ifndef MAXPHYS
128 #define MAXPHYS (128 * 1024) /* max raw I/O transfer size */
129 #endif
130 #ifndef MAXDUMPPGS
131 #define MAXDUMPPGS (DFLTPHYS/PAGE_SIZE)
132 #endif
133
134 /*
135 * Constants related to network buffer management.
136 * MCLBYTES must be no larger than PAGE_SIZE.
137 */
138 #ifndef MSIZE
139 #define MSIZE 256 /* size of an mbuf */
140 #endif /* MSIZE */
141
142 #ifndef MCLSHIFT
143 #define MCLSHIFT 11 /* convert bytes to mbuf clusters */
144 #endif /* MCLSHIFT */
145
146 #define MCLBYTES (1 << MCLSHIFT) /* size of an mbuf cluster */
147
148 #define MJUMPAGESIZE PAGE_SIZE /* jumbo cluster 4k */
149 #define MJUM9BYTES (9 * 1024) /* jumbo cluster 9k */
150 #define MJUM16BYTES (16 * 1024) /* jumbo cluster 16k */
151
152 /*
153 * Some macros for units conversion
154 */
155
156 /* clicks to bytes */
157 #ifndef ctob
158 #define ctob(x) ((x)<<PAGE_SHIFT)
159 #endif
160
161 /* bytes to clicks */
162 #ifndef btoc
163 #define btoc(x) (((vm_offset_t)(x)+PAGE_MASK)>>PAGE_SHIFT)
164 #endif
165
166 /*
167 * btodb() is messy and perhaps slow because `bytes' may be an off_t. We
168 * want to shift an unsigned type to avoid sign extension and we don't
169 * want to widen `bytes' unnecessarily. Assume that the result fits in
170 * a daddr_t.
171 */
172 #ifndef btodb
173 #define btodb(bytes) /* calculates (bytes / DEV_BSIZE) */ \
174 (sizeof (bytes) > sizeof(long) \
175 ? (daddr_t)((unsigned long long)(bytes) >> DEV_BSHIFT) \
176 : (daddr_t)((unsigned long)(bytes) >> DEV_BSHIFT))
177 #endif
178
179 #ifndef dbtob
180 #define dbtob(db) /* calculates (db * DEV_BSIZE) */ \
181 ((off_t)(db) << DEV_BSHIFT)
182 #endif
183
184 #endif /* _NO_NAMESPACE_POLLUTION */
185
186 #define PRIMASK 0x0ff
187 #define PCATCH 0x100 /* OR'd with pri for tsleep to check signals */
188 #define PDROP 0x200 /* OR'd with pri to stop re-entry of interlock mutex */
189
190 #define NZERO 0 /* default "nice" */
191
192 #define NBBY 8 /* number of bits in a byte */
193 #define NBPW sizeof(int) /* number of bytes per word (integer) */
194
195 #define CMASK 022 /* default file mask: S_IWGRP|S_IWOTH */
196
197 #define NODEV (dev_t)(-1) /* non-existent device */
198
199 #define CBLOCK 128 /* Clist block size, must be a power of 2. */
200 #define CBQSIZE (CBLOCK/NBBY) /* Quote bytes/cblock - can do better. */
201 /* Data chars/clist. */
202 #define CBSIZE (CBLOCK - sizeof(struct cblock *) - CBQSIZE)
203 #define CROUND (CBLOCK - 1) /* Clist rounding. */
204
205 /*
206 * File system parameters and macros.
207 *
208 * MAXBSIZE - Filesystems are made out of blocks of at most MAXBSIZE bytes
209 * per block. MAXBSIZE may be made larger without effecting
210 * any existing filesystems as long as it does not exceed MAXPHYS,
211 * and may be made smaller at the risk of not being able to use
212 * filesystems which require a block size exceeding MAXBSIZE.
213 *
214 * BKVASIZE - Nominal buffer space per buffer, in bytes. BKVASIZE is the
215 * minimum KVM memory reservation the kernel is willing to make.
216 * Filesystems can of course request smaller chunks. Actual
217 * backing memory uses a chunk size of a page (PAGE_SIZE).
218 *
219 * If you make BKVASIZE too small you risk seriously fragmenting
220 * the buffer KVM map which may slow things down a bit. If you
221 * make it too big the kernel will not be able to optimally use
222 * the KVM memory reserved for the buffer cache and will wind
223 * up with too-few buffers.
224 *
225 * The default is 16384, roughly 2x the block size used by a
226 * normal UFS filesystem.
227 */
228 #define MAXBSIZE 65536 /* must be power of 2 */
229 #define BKVASIZE 16384 /* must be power of 2 */
230 #define BKVAMASK (BKVASIZE-1)
231
232 /*
233 * MAXPATHLEN defines the longest permissible path length after expanding
234 * symbolic links. It is used to allocate a temporary buffer from the buffer
235 * pool in which to do the name expansion, hence should be a power of two,
236 * and must be less than or equal to MAXBSIZE. MAXSYMLINKS defines the
237 * maximum number of symbolic links that may be expanded in a path name.
238 * It should be set high enough to allow all legitimate uses, but halt
239 * infinite loops reasonably quickly.
240 */
241 #define MAXPATHLEN PATH_MAX
242 #define MAXSYMLINKS 32
243
244 /* Bit map related macros. */
245 #define setbit(a,i) (((unsigned char *)(a))[(i)/NBBY] |= 1<<((i)%NBBY))
246 #define clrbit(a,i) (((unsigned char *)(a))[(i)/NBBY] &= ~(1<<((i)%NBBY)))
247 #define isset(a,i) \
248 (((const unsigned char *)(a))[(i)/NBBY] & (1<<((i)%NBBY)))
249 #define isclr(a,i) \
250 ((((const unsigned char *)(a))[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
251
252 /* Macros for counting and rounding. */
253 #ifndef howmany
254 #define howmany(x, y) (((x)+((y)-1))/(y))
255 #endif
256 #define rounddown(x, y) (((x)/(y))*(y))
257 #define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */
258 #define roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
259 #define powerof2(x) ((((x)-1)&(x))==0)
260
261 /* Macros for min/max. */
262 #define MIN(a,b) (((a)<(b))?(a):(b))
263 #define MAX(a,b) (((a)>(b))?(a):(b))
264
265 #ifdef _KERNEL
266 /*
267 * Basic byte order function prototypes for non-inline functions.
268 */
269 #ifndef _BYTEORDER_PROTOTYPED
270 #define _BYTEORDER_PROTOTYPED
271 __BEGIN_DECLS
272 __uint32_t htonl(__uint32_t);
273 __uint16_t htons(__uint16_t);
274 __uint32_t ntohl(__uint32_t);
275 __uint16_t ntohs(__uint16_t);
276 __END_DECLS
277 #endif
278
279 #ifndef lint
280 #ifndef _BYTEORDER_FUNC_DEFINED
281 #define _BYTEORDER_FUNC_DEFINED
282 #define htonl(x) __htonl(x)
283 #define htons(x) __htons(x)
284 #define ntohl(x) __ntohl(x)
285 #define ntohs(x) __ntohs(x)
286 #endif /* !_BYTEORDER_FUNC_DEFINED */
287 #endif /* lint */
288 #endif /* _KERNEL */
289
290 /*
291 * Constants for setting the parameters of the kernel memory allocator.
292 *
293 * 2 ** MINBUCKET is the smallest unit of memory that will be
294 * allocated. It must be at least large enough to hold a pointer.
295 *
296 * Units of memory less or equal to MAXALLOCSAVE will permanently
297 * allocate physical memory; requests for these size pieces of
298 * memory are quite fast. Allocations greater than MAXALLOCSAVE must
299 * always allocate and free physical memory; requests for these
300 * size allocations should be done infrequently as they will be slow.
301 *
302 * Constraints: PAGE_SIZE <= MAXALLOCSAVE <= 2 ** (MINBUCKET + 14), and
303 * MAXALLOCSIZE must be a power of two.
304 */
305 #if defined(__alpha__) || defined(__ia64__) || defined(__sparc64__)
306 #define MINBUCKET 5 /* 5 => min allocation of 32 bytes */
307 #else
308 #define MINBUCKET 4 /* 4 => min allocation of 16 bytes */
309 #endif
310 #define MAXALLOCSAVE (2 * PAGE_SIZE)
311
312 /*
313 * Scale factor for scaled integers used to count %cpu time and load avgs.
314 *
315 * The number of CPU `tick's that map to a unique `%age' can be expressed
316 * by the formula (1 / (2 ^ (FSHIFT - 11))). The maximum load average that
317 * can be calculated (assuming 32 bits) can be closely approximated using
318 * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
319 *
320 * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
321 * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
322 */
323 #define FSHIFT 11 /* bits to right of fixed binary point */
324 #define FSCALE (1<<FSHIFT)
325
326 #define dbtoc(db) /* calculates devblks to pages */ \
327 ((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
328
329 #define ctodb(db) /* calculates pages to devblks */ \
330 ((db) << (PAGE_SHIFT - DEV_BSHIFT))
331
332 #endif /* _SYS_PARAM_H_ */
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