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: src/sys/sys/param.h,v 1.209.2.16.2.1 2006/05/12 15:47:05 kensmith Exp $
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><0 if release branch, otherwise 1>xx
56 */
57 #undef __FreeBSD_version
58 #define __FreeBSD_version 505000 /* Master, propagated to newvers */
59
60 #ifndef LOCORE
61 #include <sys/types.h>
62 #endif
63
64 /*
65 * Machine-independent constants (some used in following include files).
66 * Redefined constants are from POSIX 1003.1 limits file.
67 *
68 * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
69 * MAXLOGNAME should be == UT_NAMESIZE+1 (see <utmp.h>)
70 */
71 #include <sys/syslimits.h>
72
73 #define MAXCOMLEN 19 /* max command name remembered */
74 #define MAXINTERP 32 /* max interpreter file name length */
75 #define MAXLOGNAME 17 /* max login name length (incl. NUL) */
76 #define MAXUPRC CHILD_MAX /* max simultaneous processes */
77 #define NCARGS ARG_MAX /* max bytes for an exec function */
78 #define NGROUPS NGROUPS_MAX /* max number groups */
79 #define NOFILE OPEN_MAX /* max open files per process */
80 #define NOGROUP 65535 /* marker for empty group set member */
81 #define MAXHOSTNAMELEN 256 /* max hostname size */
82 #define SPECNAMELEN 63 /* max length of devicename */
83
84 /* More types and definitions used throughout the kernel. */
85 #ifdef _KERNEL
86 #if (defined(BURN_BRIDGES) || __FreeBSD_version >= 600000) \
87 && defined(OBSOLETE_IN_6)
88 #error "This file contains obsolete code to be removed in 6.0-current"
89 #endif
90 #include <sys/cdefs.h>
91 #include <sys/errno.h>
92 #include <sys/time.h>
93 #include <sys/priority.h>
94
95 #define FALSE 0
96 #define TRUE 1
97 #endif
98
99 #ifndef _KERNEL
100 /* Signals. */
101 #include <sys/signal.h>
102 #endif
103
104 /* Machine type dependent parameters. */
105 #include <machine/param.h>
106 #ifndef _KERNEL
107 #include <sys/limits.h>
108 #endif
109
110 #ifndef _NO_NAMESPACE_POLLUTION
111
112 #ifndef DEV_BSHIFT
113 #define DEV_BSHIFT 9 /* log2(DEV_BSIZE) */
114 #endif
115 #define DEV_BSIZE (1<<DEV_BSHIFT)
116
117 #ifndef BLKDEV_IOSIZE
118 #define BLKDEV_IOSIZE PAGE_SIZE /* default block device I/O size */
119 #endif
120 #ifndef DFLTPHYS
121 #define DFLTPHYS (64 * 1024) /* default max raw I/O transfer size */
122 #endif
123 #ifndef MAXPHYS
124 #define MAXPHYS (128 * 1024) /* max raw I/O transfer size */
125 #endif
126 #ifndef MAXDUMPPGS
127 #define MAXDUMPPGS (DFLTPHYS/PAGE_SIZE)
128 #endif
129
130 /*
131 * Constants related to network buffer management.
132 * MCLBYTES must be no larger than PAGE_SIZE.
133 */
134 #ifndef MSIZE
135 #define MSIZE 256 /* size of an mbuf */
136 #endif /* MSIZE */
137
138 #ifndef MCLSHIFT
139 #define MCLSHIFT 11 /* convert bytes to mbuf clusters */
140 #endif /* MCLSHIFT */
141
142 #define MCLBYTES (1 << MCLSHIFT) /* size of an mbuf cluster */
143
144 /*
145 * Some macros for units conversion
146 */
147
148 /* clicks to bytes */
149 #ifndef ctob
150 #define ctob(x) ((x)<<PAGE_SHIFT)
151 #endif
152
153 /* bytes to clicks */
154 #ifndef btoc
155 #define btoc(x) (((vm_offset_t)(x)+PAGE_MASK)>>PAGE_SHIFT)
156 #endif
157
158 /*
159 * btodb() is messy and perhaps slow because `bytes' may be an off_t. We
160 * want to shift an unsigned type to avoid sign extension and we don't
161 * want to widen `bytes' unnecessarily. Assume that the result fits in
162 * a daddr_t.
163 */
164 #ifndef btodb
165 #define btodb(bytes) /* calculates (bytes / DEV_BSIZE) */ \
166 (sizeof (bytes) > sizeof(long) \
167 ? (daddr_t)((unsigned long long)(bytes) >> DEV_BSHIFT) \
168 : (daddr_t)((unsigned long)(bytes) >> DEV_BSHIFT))
169 #endif
170
171 #ifndef dbtob
172 #define dbtob(db) /* calculates (db * DEV_BSIZE) */ \
173 ((off_t)(db) << DEV_BSHIFT)
174 #endif
175
176 #endif /* _NO_NAMESPACE_POLLUTION */
177
178 #define PRIMASK 0x0ff
179 #define PCATCH 0x100 /* OR'd with pri for tsleep to check signals */
180 #define PDROP 0x200 /* OR'd with pri to stop re-entry of interlock mutex */
181
182 #define NZERO 0 /* default "nice" */
183
184 #define NBBY 8 /* number of bits in a byte */
185 #define NBPW sizeof(int) /* number of bytes per word (integer) */
186
187 #define CMASK 022 /* default file mask: S_IWGRP|S_IWOTH */
188
189 #define NODEV (dev_t)(-1) /* non-existent device */
190
191 #define CBLOCK 128 /* Clist block size, must be a power of 2. */
192 #define CBQSIZE (CBLOCK/NBBY) /* Quote bytes/cblock - can do better. */
193 /* Data chars/clist. */
194 #define CBSIZE (CBLOCK - sizeof(struct cblock *) - CBQSIZE)
195 #define CROUND (CBLOCK - 1) /* Clist rounding. */
196
197 /*
198 * File system parameters and macros.
199 *
200 * MAXBSIZE - Filesystems are made out of blocks of at most MAXBSIZE bytes
201 * per block. MAXBSIZE may be made larger without effecting
202 * any existing filesystems as long as it does not exceed MAXPHYS,
203 * and may be made smaller at the risk of not being able to use
204 * filesystems which require a block size exceeding MAXBSIZE.
205 *
206 * BKVASIZE - Nominal buffer space per buffer, in bytes. BKVASIZE is the
207 * minimum KVM memory reservation the kernel is willing to make.
208 * Filesystems can of course request smaller chunks. Actual
209 * backing memory uses a chunk size of a page (PAGE_SIZE).
210 *
211 * If you make BKVASIZE too small you risk seriously fragmenting
212 * the buffer KVM map which may slow things down a bit. If you
213 * make it too big the kernel will not be able to optimally use
214 * the KVM memory reserved for the buffer cache and will wind
215 * up with too-few buffers.
216 *
217 * The default is 16384, roughly 2x the block size used by a
218 * normal UFS filesystem.
219 */
220 #define MAXBSIZE 65536 /* must be power of 2 */
221 #define BKVASIZE 16384 /* must be power of 2 */
222 #define BKVAMASK (BKVASIZE-1)
223
224 /*
225 * MAXPATHLEN defines the longest permissible path length after expanding
226 * symbolic links. It is used to allocate a temporary buffer from the buffer
227 * pool in which to do the name expansion, hence should be a power of two,
228 * and must be less than or equal to MAXBSIZE. MAXSYMLINKS defines the
229 * maximum number of symbolic links that may be expanded in a path name.
230 * It should be set high enough to allow all legitimate uses, but halt
231 * infinite loops reasonably quickly.
232 */
233 #define MAXPATHLEN PATH_MAX
234 #define MAXSYMLINKS 32
235
236 /* Bit map related macros. */
237 #define setbit(a,i) ((a)[(i)/NBBY] |= 1<<((i)%NBBY))
238 #define clrbit(a,i) ((a)[(i)/NBBY] &= ~(1<<((i)%NBBY)))
239 #define isset(a,i) ((a)[(i)/NBBY] & (1<<((i)%NBBY)))
240 #define isclr(a,i) (((a)[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
241
242 /* Macros for counting and rounding. */
243 #ifndef howmany
244 #define howmany(x, y) (((x)+((y)-1))/(y))
245 #endif
246 #define rounddown(x, y) (((x)/(y))*(y))
247 #define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */
248 #define roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
249 #define powerof2(x) ((((x)-1)&(x))==0)
250
251 /* Macros for min/max. */
252 #define MIN(a,b) (((a)<(b))?(a):(b))
253 #define MAX(a,b) (((a)>(b))?(a):(b))
254
255 #ifdef _KERNEL
256 /*
257 * Basic byte order function prototypes for non-inline functions.
258 */
259 #ifndef _BYTEORDER_PROTOTYPED
260 #define _BYTEORDER_PROTOTYPED
261 __BEGIN_DECLS
262 __uint32_t htonl(__uint32_t);
263 __uint16_t htons(__uint16_t);
264 __uint32_t ntohl(__uint32_t);
265 __uint16_t ntohs(__uint16_t);
266 __END_DECLS
267 #endif
268
269 #ifndef lint
270 #ifndef _BYTEORDER_FUNC_DEFINED
271 #define _BYTEORDER_FUNC_DEFINED
272 #define htonl(x) __htonl(x)
273 #define htons(x) __htons(x)
274 #define ntohl(x) __ntohl(x)
275 #define ntohs(x) __ntohs(x)
276 #endif /* !_BYTEORDER_FUNC_DEFINED */
277 #endif /* lint */
278 #endif /* _KERNEL */
279
280 /*
281 * Constants for setting the parameters of the kernel memory allocator.
282 *
283 * 2 ** MINBUCKET is the smallest unit of memory that will be
284 * allocated. It must be at least large enough to hold a pointer.
285 *
286 * Units of memory less or equal to MAXALLOCSAVE will permanently
287 * allocate physical memory; requests for these size pieces of
288 * memory are quite fast. Allocations greater than MAXALLOCSAVE must
289 * always allocate and free physical memory; requests for these
290 * size allocations should be done infrequently as they will be slow.
291 *
292 * Constraints: PAGE_SIZE <= MAXALLOCSAVE <= 2 ** (MINBUCKET + 14), and
293 * MAXALLOCSIZE must be a power of two.
294 */
295 #if defined(__alpha__) || defined(__ia64__) || defined(__sparc64__)
296 #define MINBUCKET 5 /* 5 => min allocation of 32 bytes */
297 #else
298 #define MINBUCKET 4 /* 4 => min allocation of 16 bytes */
299 #endif
300 #define MAXALLOCSAVE (2 * PAGE_SIZE)
301
302 /*
303 * Scale factor for scaled integers used to count %cpu time and load avgs.
304 *
305 * The number of CPU `tick's that map to a unique `%age' can be expressed
306 * by the formula (1 / (2 ^ (FSHIFT - 11))). The maximum load average that
307 * can be calculated (assuming 32 bits) can be closely approximated using
308 * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
309 *
310 * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
311 * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
312 */
313 #define FSHIFT 11 /* bits to right of fixed binary point */
314 #define FSCALE (1<<FSHIFT)
315
316 #define dbtoc(db) /* calculates devblks to pages */ \
317 ((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
318
319 #define ctodb(db) /* calculates pages to devblks */ \
320 ((db) << (PAGE_SHIFT - DEV_BSHIFT))
321
322 #endif /* _SYS_PARAM_H_ */
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