2 * Copyright (c) 1982, 1986, 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
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6 * to the University of California by American Telephone and Telegraph
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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
54 #undef __FreeBSD_version
55 #define __FreeBSD_version 500031 /* Master, propagated to newvers */
62 #include <sys/types.h>
66 * Machine-independent constants (some used in following include files).
67 * Redefined constants are from POSIX 1003.1 limits file.
69 * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
70 * MAXLOGNAME should be == UT_NAMESIZE+1 (see <utmp.h>)
72 #include <sys/syslimits.h>
74 #define MAXCOMLEN 19 /* max command name remembered */
75 #define MAXINTERP 32 /* max interpreter file name length */
76 #define MAXLOGNAME 17 /* max login name length (incl. NUL) */
77 #define MAXUPRC CHILD_MAX /* max simultaneous processes */
78 #define NCARGS ARG_MAX /* max bytes for an exec function */
79 #define NGROUPS NGROUPS_MAX /* max number groups */
80 #define NOFILE OPEN_MAX /* max open files per process */
81 #define NOGROUP 65535 /* marker for empty group set member */
82 #define MAXHOSTNAMELEN 256 /* max hostname size */
83 #define SPECNAMELEN 15 /* max length of devicename */
85 /* More types and definitions used throughout the kernel. */
87 #include <sys/cdefs.h>
88 #include <sys/errno.h>
90 #include <sys/priority.h>
98 #include <sys/signal.h>
101 /* Machine type dependent parameters. */
102 #include <machine/param.h>
104 #include <machine/limits.h>
107 #define PRIMASK 0x0ff
108 #define PCATCH 0x100 /* OR'd with pri for tsleep to check signals */
109 #define PDROP 0x200 /* OR'd with pri to stop re-entry of interlock mutex */
111 #define NZERO 0 /* default "nice" */
113 #define NBPW sizeof(int) /* number of bytes per word (integer) */
115 #define CMASK 022 /* default file mask: S_IWGRP|S_IWOTH */
117 #define NODEV (dev_t)(-1) /* non-existent device */
118 #define NOUDEV (udev_t)(-1) /* non-existent device */
119 #define NOMAJ 256 /* non-existent device */
121 #define NODEV (dev_t)(-1) /* non-existent device */
124 #define CBLOCK 128 /* Clist block size, must be a power of 2. */
125 #define CBQSIZE (CBLOCK/NBBY) /* Quote bytes/cblock - can do better. */
126 /* Data chars/clist. */
127 #define CBSIZE (CBLOCK - sizeof(struct cblock *) - CBQSIZE)
128 #define CROUND (CBLOCK - 1) /* Clist rounding. */
131 * File system parameters and macros.
133 * MAXBSIZE - Filesystems are made out of blocks of at most MAXBSIZE bytes
134 * per block. MAXBSIZE may be made larger without effecting
135 * any existing filesystems as long as it does not exceed MAXPHYS,
136 * and may be made smaller at the risk of not being able to use
137 * filesystems which require a block size exceeding MAXBSIZE.
139 * BKVASIZE - Nominal buffer space per buffer, in bytes. BKVASIZE is the
140 * minimum KVM memory reservation the kernel is willing to make.
141 * Filesystems can of course request smaller chunks. Actual
142 * backing memory uses a chunk size of a page (PAGE_SIZE).
144 * If you make BKVASIZE too small you risk seriously fragmenting
145 * the buffer KVM map which may slow things down a bit. If you
146 * make it too big the kernel will not be able to optimally use
147 * the KVM memory reserved for the buffer cache and will wind
148 * up with too-few buffers.
150 * The default is 16384, roughly 2x the block size used by a
151 * normal UFS filesystem.
153 #define MAXBSIZE 65536 /* must be power of 2 */
154 #define BKVASIZE 16384 /* must be power of 2 */
155 #define BKVAMASK (BKVASIZE-1)
159 * MAXPATHLEN defines the longest permissible path length after expanding
160 * symbolic links. It is used to allocate a temporary buffer from the buffer
161 * pool in which to do the name expansion, hence should be a power of two,
162 * and must be less than or equal to MAXBSIZE. MAXSYMLINKS defines the
163 * maximum number of symbolic links that may be expanded in a path name.
164 * It should be set high enough to allow all legitimate uses, but halt
165 * infinite loops reasonably quickly.
167 #define MAXPATHLEN PATH_MAX
168 #define MAXSYMLINKS 32
170 /* Bit map related macros. */
171 #define setbit(a,i) ((a)[(i)/NBBY] |= 1<<((i)%NBBY))
172 #define clrbit(a,i) ((a)[(i)/NBBY] &= ~(1<<((i)%NBBY)))
173 #define isset(a,i) ((a)[(i)/NBBY] & (1<<((i)%NBBY)))
174 #define isclr(a,i) (((a)[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
176 /* Macros for counting and rounding. */
178 #define howmany(x, y) (((x)+((y)-1))/(y))
180 #define rounddown(x, y) (((x)/(y))*(y))
181 #define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */
182 #define roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
183 #define powerof2(x) ((((x)-1)&(x))==0)
185 /* Macros for min/max. */
187 #define MIN(a,b) (((a)<(b))?(a):(b))
188 #define MAX(a,b) (((a)>(b))?(a):(b))
192 * Kernel exposed versions of byteorder(3) functions.
194 * XXX this section should only be defined in the kernel, but some userland
195 * software utilizes it.
197 #ifndef _BYTEORDER_FUNC_DEFINED
198 #define _BYTEORDER_FUNC_DEFINED
199 #define htonl(x) __htonl(x)
200 #define htons(x) __htons(x)
201 #define ntohl(x) __ntohl(x)
202 #define ntohs(x) __ntohs(x)
206 * XXX deprecated uppercase variants for byteorder(3) functions.
208 #ifndef _POSIX_SOURCE
209 #define NTOHL(x) ((x) = __ntohl(x))
210 #define NTOHS(x) ((x) = __ntohs(x))
211 #define HTONL(x) ((x) = __htonl(x))
212 #define HTONS(x) ((x) = __htons(x))
213 #endif /* _POSIX_SOURCE */
216 * Constants for setting the parameters of the kernel memory allocator.
218 * 2 ** MINBUCKET is the smallest unit of memory that will be
219 * allocated. It must be at least large enough to hold a pointer.
221 * Units of memory less or equal to MAXALLOCSAVE will permanently
222 * allocate physical memory; requests for these size pieces of
223 * memory are quite fast. Allocations greater than MAXALLOCSAVE must
224 * always allocate and free physical memory; requests for these
225 * size allocations should be done infrequently as they will be slow.
227 * Constraints: PAGE_SIZE <= MAXALLOCSAVE <= 2 ** (MINBUCKET + 14), and
228 * MAXALLOCSIZE must be a power of two.
230 #if defined(__alpha__) || defined(__ia64__) || defined(__sparc64__)
231 #define MINBUCKET 5 /* 5 => min allocation of 32 bytes */
233 #define MINBUCKET 4 /* 4 => min allocation of 16 bytes */
235 #define MAXALLOCSAVE (2 * PAGE_SIZE)
238 * Scale factor for scaled integers used to count %cpu time and load avgs.
240 * The number of CPU `tick's that map to a unique `%age' can be expressed
241 * by the formula (1 / (2 ^ (FSHIFT - 11))). The maximum load average that
242 * can be calculated (assuming 32 bits) can be closely approximated using
243 * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
245 * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
246 * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
248 #define FSHIFT 11 /* bits to right of fixed binary point */
249 #define FSCALE (1<<FSHIFT)
251 #define dbtoc(db) /* calculates devblks to pages */ \
252 ((db + (ctodb(1) - 1)) >> (PAGE_SHIFT - DEV_BSHIFT))
254 #define ctodb(db) /* calculates pages to devblks */ \
255 ((db) << (PAGE_SHIFT - DEV_BSHIFT))
257 #endif /* _SYS_PARAM_H_ */