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4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
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8 * the permission of UNIX System Laboratories, Inc.
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38 * @(#)param.h 8.3 (Berkeley) 4/4/95
45 #define BSD 199506 /* System version (year & month). */
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
53 * Currently this lives here:
55 * doc/en_US.ISO8859-1/books/porters-handbook/book.sgml
57 * scheme is: <major><two digit minor><0 if release branch, otherwise 1>xx
59 #undef __FreeBSD_version
60 #define __FreeBSD_version 501110 /* Master, propagated to newvers */
67 #include <sys/types.h>
71 * Machine-independent constants (some used in following include files).
72 * Redefined constants are from POSIX 1003.1 limits file.
74 * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
75 * MAXLOGNAME should be == UT_NAMESIZE+1 (see <utmp.h>)
77 #include <sys/syslimits.h>
79 #define MAXCOMLEN 19 /* max command name remembered */
80 #define MAXINTERP 32 /* max interpreter file name length */
81 #define MAXLOGNAME 17 /* max login name length (incl. NUL) */
82 #define MAXUPRC CHILD_MAX /* max simultaneous processes */
83 #define NCARGS ARG_MAX /* max bytes for an exec function */
84 #define NGROUPS NGROUPS_MAX /* max number groups */
85 #define NOFILE OPEN_MAX /* max open files per process */
86 #define NOGROUP 65535 /* marker for empty group set member */
87 #define MAXHOSTNAMELEN 256 /* max hostname size */
88 #define SPECNAMELEN 63 /* max length of devicename */
90 /* More types and definitions used throughout the kernel. */
92 #if (defined(BURN_BRIDGES) || __FreeBSD_version >= 600000) \
93 && defined(OBSOLETE_IN_6)
94 #error "This file contains obsolete code to be removed in 6.0-current"
96 #include <sys/cdefs.h>
97 #include <sys/errno.h>
99 #include <sys/priority.h>
107 #include <sys/signal.h>
110 /* Machine type dependent parameters. */
111 #include <machine/param.h>
113 #include <sys/limits.h>
116 #ifndef _NO_NAMESPACE_POLLUTION
119 #define DEV_BSHIFT 9 /* log2(DEV_BSIZE) */
121 #define DEV_BSIZE (1<<DEV_BSHIFT)
123 #ifndef BLKDEV_IOSIZE
124 #define BLKDEV_IOSIZE PAGE_SIZE /* default block device I/O size */
127 #define DFLTPHYS (64 * 1024) /* default max raw I/O transfer size */
130 #define MAXPHYS (128 * 1024) /* max raw I/O transfer size */
133 #define MAXDUMPPGS (DFLTPHYS/PAGE_SIZE)
137 * Constants related to network buffer management.
138 * MCLBYTES must be no larger than PAGE_SIZE.
141 #define MSIZE 256 /* size of an mbuf */
145 #define MCLSHIFT 11 /* convert bytes to mbuf clusters */
146 #endif /* MCLSHIFT */
148 #define MCLBYTES (1 << MCLSHIFT) /* size of an mbuf cluster */
151 * Some macros for units conversion
154 /* clicks to bytes */
156 #define ctob(x) ((x)<<PAGE_SHIFT)
159 /* bytes to clicks */
161 #define btoc(x) (((vm_offset_t)(x)+PAGE_MASK)>>PAGE_SHIFT)
165 * btodb() is messy and perhaps slow because `bytes' may be an off_t. We
166 * want to shift an unsigned type to avoid sign extension and we don't
167 * want to widen `bytes' unnecessarily. Assume that the result fits in
171 #define btodb(bytes) /* calculates (bytes / DEV_BSIZE) */ \
172 (sizeof (bytes) > sizeof(long) \
173 ? (daddr_t)((unsigned long long)(bytes) >> DEV_BSHIFT) \
174 : (daddr_t)((unsigned long)(bytes) >> DEV_BSHIFT))
178 #define dbtob(db) /* calculates (db * DEV_BSIZE) */ \
179 ((off_t)(db) << DEV_BSHIFT)
182 #endif /* _NO_NAMESPACE_POLLUTION */
184 #define PRIMASK 0x0ff
185 #define PCATCH 0x100 /* OR'd with pri for tsleep to check signals */
186 #define PDROP 0x200 /* OR'd with pri to stop re-entry of interlock mutex */
188 #define NZERO 0 /* default "nice" */
190 #define NBBY 8 /* number of bits in a byte */
191 #define NBPW sizeof(int) /* number of bytes per word (integer) */
193 #define CMASK 022 /* default file mask: S_IWGRP|S_IWOTH */
194 #define NODEV (dev_t)(-1) /* non-existent device */
196 #define NOUDEV (udev_t)(-1) /* non-existent device */
197 #define NOMAJ 256 /* non-existent device */
200 #define CBLOCK 128 /* Clist block size, must be a power of 2. */
201 #define CBQSIZE (CBLOCK/NBBY) /* Quote bytes/cblock - can do better. */
202 /* Data chars/clist. */
203 #define CBSIZE (CBLOCK - sizeof(struct cblock *) - CBQSIZE)
204 #define CROUND (CBLOCK - 1) /* Clist rounding. */
207 * File system parameters and macros.
209 * MAXBSIZE - Filesystems are made out of blocks of at most MAXBSIZE bytes
210 * per block. MAXBSIZE may be made larger without effecting
211 * any existing filesystems as long as it does not exceed MAXPHYS,
212 * and may be made smaller at the risk of not being able to use
213 * filesystems which require a block size exceeding MAXBSIZE.
215 * BKVASIZE - Nominal buffer space per buffer, in bytes. BKVASIZE is the
216 * minimum KVM memory reservation the kernel is willing to make.
217 * Filesystems can of course request smaller chunks. Actual
218 * backing memory uses a chunk size of a page (PAGE_SIZE).
220 * If you make BKVASIZE too small you risk seriously fragmenting
221 * the buffer KVM map which may slow things down a bit. If you
222 * make it too big the kernel will not be able to optimally use
223 * the KVM memory reserved for the buffer cache and will wind
224 * up with too-few buffers.
226 * The default is 16384, roughly 2x the block size used by a
227 * normal UFS filesystem.
229 #define MAXBSIZE 65536 /* must be power of 2 */
230 #define BKVASIZE 16384 /* must be power of 2 */
231 #define BKVAMASK (BKVASIZE-1)
234 * MAXPATHLEN defines the longest permissible path length after expanding
235 * symbolic links. It is used to allocate a temporary buffer from the buffer
236 * pool in which to do the name expansion, hence should be a power of two,
237 * and must be less than or equal to MAXBSIZE. MAXSYMLINKS defines the
238 * maximum number of symbolic links that may be expanded in a path name.
239 * It should be set high enough to allow all legitimate uses, but halt
240 * infinite loops reasonably quickly.
242 #define MAXPATHLEN PATH_MAX
243 #define MAXSYMLINKS 32
245 /* Bit map related macros. */
246 #define setbit(a,i) ((a)[(i)/NBBY] |= 1<<((i)%NBBY))
247 #define clrbit(a,i) ((a)[(i)/NBBY] &= ~(1<<((i)%NBBY)))
248 #define isset(a,i) ((a)[(i)/NBBY] & (1<<((i)%NBBY)))
249 #define isclr(a,i) (((a)[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
251 /* Macros for counting and rounding. */
253 #define howmany(x, y) (((x)+((y)-1))/(y))
255 #define rounddown(x, y) (((x)/(y))*(y))
256 #define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */
257 #define roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
258 #define powerof2(x) ((((x)-1)&(x))==0)
260 /* Macros for min/max. */
261 #define MIN(a,b) (((a)<(b))?(a):(b))
262 #define MAX(a,b) (((a)>(b))?(a):(b))
266 * Basic byte order function prototypes for non-inline functions.
268 #ifndef _BYTEORDER_PROTOTYPED
269 #define _BYTEORDER_PROTOTYPED
271 __uint32_t htonl(__uint32_t);
272 __uint16_t htons(__uint16_t);
273 __uint32_t ntohl(__uint32_t);
274 __uint16_t ntohs(__uint16_t);
279 #ifndef _BYTEORDER_FUNC_DEFINED
280 #define _BYTEORDER_FUNC_DEFINED
281 #define htonl(x) __htonl(x)
282 #define htons(x) __htons(x)
283 #define ntohl(x) __ntohl(x)
284 #define ntohs(x) __ntohs(x)
285 #endif /* !_BYTEORDER_FUNC_DEFINED */
290 * Constants for setting the parameters of the kernel memory allocator.
292 * 2 ** MINBUCKET is the smallest unit of memory that will be
293 * allocated. It must be at least large enough to hold a pointer.
295 * Units of memory less or equal to MAXALLOCSAVE will permanently
296 * allocate physical memory; requests for these size pieces of
297 * memory are quite fast. Allocations greater than MAXALLOCSAVE must
298 * always allocate and free physical memory; requests for these
299 * size allocations should be done infrequently as they will be slow.
301 * Constraints: PAGE_SIZE <= MAXALLOCSAVE <= 2 ** (MINBUCKET + 14), and
302 * MAXALLOCSIZE must be a power of two.
304 #if defined(__alpha__) || defined(__ia64__) || defined(__sparc64__)
305 #define MINBUCKET 5 /* 5 => min allocation of 32 bytes */
307 #define MINBUCKET 4 /* 4 => min allocation of 16 bytes */
309 #define MAXALLOCSAVE (2 * PAGE_SIZE)
312 * Scale factor for scaled integers used to count %cpu time and load avgs.
314 * The number of CPU `tick's that map to a unique `%age' can be expressed
315 * by the formula (1 / (2 ^ (FSHIFT - 11))). The maximum load average that
316 * can be calculated (assuming 32 bits) can be closely approximated using
317 * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
319 * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
320 * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
322 #define FSHIFT 11 /* bits to right of fixed binary point */
323 #define FSCALE (1<<FSHIFT)
325 #define dbtoc(db) /* calculates devblks to pages */ \
326 ((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
328 #define ctodb(db) /* calculates pages to devblks */ \
329 ((db) << (PAGE_SHIFT - DEV_BSHIFT))
331 #endif /* _SYS_PARAM_H_ */