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34 * @(#)param.h 8.3 (Berkeley) 4/4/95
41 #include <sys/_null.h>
43 #define BSD 199506 /* System version (year & month). */
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
51 * Currently this lives here:
53 * doc/en_US.ISO8859-1/books/porters-handbook/book.sgml
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.
59 #undef __FreeBSD_version
60 #define __FreeBSD_version 800005 /* Master, propagated to newvers */
63 #include <sys/types.h>
67 * Machine-independent constants (some used in following include files).
68 * Redefined constants are from POSIX 1003.1 limits file.
70 * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
71 * MAXLOGNAME should be == UT_NAMESIZE+1 (see <utmp.h>)
73 #include <sys/syslimits.h>
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 */
86 /* More types and definitions used throughout the kernel. */
88 #include <sys/cdefs.h>
89 #include <sys/errno.h>
92 #include <sys/priority.h>
101 #include <sys/signal.h>
104 /* Machine type dependent parameters. */
105 #include <machine/param.h>
107 #include <sys/limits.h>
110 #ifndef _NO_NAMESPACE_POLLUTION
113 #define DEV_BSHIFT 9 /* log2(DEV_BSIZE) */
115 #define DEV_BSIZE (1<<DEV_BSHIFT)
117 #ifndef BLKDEV_IOSIZE
118 #define BLKDEV_IOSIZE PAGE_SIZE /* default block device I/O size */
121 #define DFLTPHYS (64 * 1024) /* default max raw I/O transfer size */
124 #define MAXPHYS (128 * 1024) /* max raw I/O transfer size */
127 #define MAXDUMPPGS (DFLTPHYS/PAGE_SIZE)
131 * Constants related to network buffer management.
132 * MCLBYTES must be no larger than PAGE_SIZE.
135 #define MSIZE 256 /* size of an mbuf */
139 #define MCLSHIFT 11 /* convert bytes to mbuf clusters */
140 #endif /* MCLSHIFT */
142 #define MCLBYTES (1 << MCLSHIFT) /* size of an mbuf cluster */
144 #define MJUMPAGESIZE PAGE_SIZE /* jumbo cluster 4k */
145 #define MJUM9BYTES (9 * 1024) /* jumbo cluster 9k */
146 #define MJUM16BYTES (16 * 1024) /* jumbo cluster 16k */
149 * Some macros for units conversion
152 /* clicks to bytes */
154 #define ctob(x) ((x)<<PAGE_SHIFT)
157 /* bytes to clicks */
159 #define btoc(x) (((vm_offset_t)(x)+PAGE_MASK)>>PAGE_SHIFT)
163 * btodb() is messy and perhaps slow because `bytes' may be an off_t. We
164 * want to shift an unsigned type to avoid sign extension and we don't
165 * want to widen `bytes' unnecessarily. Assume that the result fits in
169 #define btodb(bytes) /* calculates (bytes / DEV_BSIZE) */ \
170 (sizeof (bytes) > sizeof(long) \
171 ? (daddr_t)((unsigned long long)(bytes) >> DEV_BSHIFT) \
172 : (daddr_t)((unsigned long)(bytes) >> DEV_BSHIFT))
176 #define dbtob(db) /* calculates (db * DEV_BSIZE) */ \
177 ((off_t)(db) << DEV_BSHIFT)
180 #endif /* _NO_NAMESPACE_POLLUTION */
182 #define PRIMASK 0x0ff
183 #define PCATCH 0x100 /* OR'd with pri for tsleep to check signals */
184 #define PDROP 0x200 /* OR'd with pri to stop re-entry of interlock mutex */
186 #define NZERO 0 /* default "nice" */
188 #define NBBY 8 /* number of bits in a byte */
189 #define NBPW sizeof(int) /* number of bytes per word (integer) */
191 #define CMASK 022 /* default file mask: S_IWGRP|S_IWOTH */
193 #define NODEV (dev_t)(-1) /* non-existent device */
195 #define CBLOCK 128 /* Clist block size, must be a power of 2. */
196 #define CBQSIZE (CBLOCK/NBBY) /* Quote bytes/cblock - can do better. */
197 /* Data chars/clist. */
198 #define CBSIZE (CBLOCK - sizeof(struct cblock *) - CBQSIZE)
199 #define CROUND (CBLOCK - 1) /* Clist rounding. */
202 * File system parameters and macros.
204 * MAXBSIZE - Filesystems are made out of blocks of at most MAXBSIZE bytes
205 * per block. MAXBSIZE may be made larger without effecting
206 * any existing filesystems as long as it does not exceed MAXPHYS,
207 * and may be made smaller at the risk of not being able to use
208 * filesystems which require a block size exceeding MAXBSIZE.
210 * BKVASIZE - Nominal buffer space per buffer, in bytes. BKVASIZE is the
211 * minimum KVM memory reservation the kernel is willing to make.
212 * Filesystems can of course request smaller chunks. Actual
213 * backing memory uses a chunk size of a page (PAGE_SIZE).
215 * If you make BKVASIZE too small you risk seriously fragmenting
216 * the buffer KVM map which may slow things down a bit. If you
217 * make it too big the kernel will not be able to optimally use
218 * the KVM memory reserved for the buffer cache and will wind
219 * up with too-few buffers.
221 * The default is 16384, roughly 2x the block size used by a
222 * normal UFS filesystem.
224 #define MAXBSIZE 65536 /* must be power of 2 */
225 #define BKVASIZE 16384 /* must be power of 2 */
226 #define BKVAMASK (BKVASIZE-1)
229 * MAXPATHLEN defines the longest permissible path length after expanding
230 * symbolic links. It is used to allocate a temporary buffer from the buffer
231 * pool in which to do the name expansion, hence should be a power of two,
232 * and must be less than or equal to MAXBSIZE. MAXSYMLINKS defines the
233 * maximum number of symbolic links that may be expanded in a path name.
234 * It should be set high enough to allow all legitimate uses, but halt
235 * infinite loops reasonably quickly.
237 #define MAXPATHLEN PATH_MAX
238 #define MAXSYMLINKS 32
240 /* Bit map related macros. */
241 #define setbit(a,i) (((uint8_t *)(a))[(i)/NBBY] |= 1<<((i)%NBBY))
242 #define clrbit(a,i) (((uint8_t *)(a))[(i)/NBBY] &= ~(1<<((i)%NBBY)))
243 #define isset(a,i) (((uint8_t *)(a))[(i)/NBBY] & (1<<((i)%NBBY)))
244 #define isclr(a,i) ((((uint8_t *)(a))[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
246 /* Macros for counting and rounding. */
248 #define howmany(x, y) (((x)+((y)-1))/(y))
250 #define rounddown(x, y) (((x)/(y))*(y))
251 #define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */
252 #define roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
253 #define powerof2(x) ((((x)-1)&(x))==0)
255 /* Macros for min/max. */
256 #define MIN(a,b) (((a)<(b))?(a):(b))
257 #define MAX(a,b) (((a)>(b))?(a):(b))
261 * Basic byte order function prototypes for non-inline functions.
264 #ifndef _BYTEORDER_PROTOTYPED
265 #define _BYTEORDER_PROTOTYPED
267 __uint32_t htonl(__uint32_t);
268 __uint16_t htons(__uint16_t);
269 __uint32_t ntohl(__uint32_t);
270 __uint16_t ntohs(__uint16_t);
276 #ifndef _BYTEORDER_FUNC_DEFINED
277 #define _BYTEORDER_FUNC_DEFINED
278 #define htonl(x) __htonl(x)
279 #define htons(x) __htons(x)
280 #define ntohl(x) __ntohl(x)
281 #define ntohs(x) __ntohs(x)
282 #endif /* !_BYTEORDER_FUNC_DEFINED */
287 * Scale factor for scaled integers used to count %cpu time and load avgs.
289 * The number of CPU `tick's that map to a unique `%age' can be expressed
290 * by the formula (1 / (2 ^ (FSHIFT - 11))). The maximum load average that
291 * can be calculated (assuming 32 bits) can be closely approximated using
292 * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
294 * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
295 * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
297 #define FSHIFT 11 /* bits to right of fixed binary point */
298 #define FSCALE (1<<FSHIFT)
300 #define dbtoc(db) /* calculates devblks to pages */ \
301 ((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
303 #define ctodb(db) /* calculates pages to devblks */ \
304 ((db) << (PAGE_SHIFT - DEV_BSHIFT))
306 #endif /* _SYS_PARAM_H_ */