xref: /minix/sys/sys/param.h (revision 0a6a1f1d)
1 /*	$NetBSD: param.h,v 1.486 2015/08/29 14:07:45 uebayasi Exp $	*/
2 
3 /*-
4  * Copyright (c) 1982, 1986, 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  * (c) UNIX System Laboratories, Inc.
7  * All or some portions of this file are derived from material licensed
8  * to the University of California by American Telephone and Telegraph
9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10  * the permission of UNIX System Laboratories, Inc.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *	@(#)param.h	8.3 (Berkeley) 4/4/95
37  */
38 
39 #ifndef _SYS_PARAM_H_
40 #define	_SYS_PARAM_H_
41 
42 #ifdef _KERNEL_OPT
43 #include "opt_param.h"
44 #endif
45 
46 /*
47  * Historic BSD #defines -- probably will remain untouched for all time.
48  */
49 #define	BSD	199506		/* System version (year & month). */
50 #define	BSD4_3	1
51 #define	BSD4_4	1
52 
53 /*
54  *	#define __NetBSD_Version__ MMmmrrpp00
55  *
56  *	M = major version
57  *	m = minor version; a minor number of 99 indicates current.
58  *	r = 0 (*)
59  *	p = patchlevel
60  *
61  * When new releases are made, src/gnu/usr.bin/groff/tmac/mdoc.local
62  * needs to be updated and the changes sent back to the groff maintainers.
63  *
64  * (*)	Up to 2.0I "release" used to be "",A-Z,Z[A-Z] but numeric
65  *	    	e.g. NetBSD-1.2D  = 102040000 ('D' == 4)
66  *	NetBSD-2.0H 	(200080000) was changed on 20041001 to:
67  *	2.99.9		(299000900)
68  */
69 
70 #define	__NetBSD_Version__	799002100	/* NetBSD 7.99.21 */
71 
72 #define __NetBSD_Prereq__(M,m,p) (((((M) * 100000000) + \
73     (m) * 1000000) + (p) * 100) <= __NetBSD_Version__)
74 
75 /*
76  * Historical NetBSD #define
77  *
78  * NetBSD 1.4 was the last release for which this value was incremented.
79  * The value is now permanently fixed at 199905. It will never be
80  * changed again.
81  *
82  * New code must use __NetBSD_Version__ instead, and should not even
83  * count on NetBSD being defined.
84  *
85  */
86 
87 #define	NetBSD	199905		/* NetBSD version (year & month). */
88 
89 /*
90  * There macros determine if we are running in protected mode or not.
91  *   _HARDKERNEL: code uses kernel namespace and runs in hw priviledged mode
92  *   _SOFTKERNEL: code uses kernel namespace but runs without hw priviledges
93  */
94 #if defined(_KERNEL) && !defined(_RUMPKERNEL)
95 #define _HARDKERNEL
96 #endif
97 #if defined(_KERNEL) && defined(_RUMPKERNEL)
98 #define _SOFTKERNEL
99 #endif
100 
101 #include <sys/null.h>
102 
103 #ifndef __ASSEMBLER__
104 #include <sys/inttypes.h>
105 #include <sys/types.h>
106 
107 /*
108  * Machine-independent constants (some used in following include files).
109  * Redefined constants are from POSIX 1003.1 limits file.
110  *
111  * MAXCOMLEN should be >= sizeof(ac_comm) (see <acct.h>)
112  * MAXHOSTNAMELEN should be >= (_POSIX_HOST_NAME_MAX + 1) (see <limits.h>)
113  * MAXLOGNAME should be >= UT_NAMESIZE (see <utmp.h>)
114  */
115 #include <sys/syslimits.h>
116 
117 #define	MAXCOMLEN	16		/* max command name remembered */
118 #define	MAXINTERP	PATH_MAX	/* max interpreter file name length */
119 /* DEPRECATED: use LOGIN_NAME_MAX instead. */
120 #define	MAXLOGNAME	(LOGIN_NAME_MAX - 1) /* max login name length */
121 #define	NCARGS		ARG_MAX		/* max bytes for an exec function */
122 #define	NGROUPS		NGROUPS_MAX	/* max number groups */
123 #define	NOGROUP		65535		/* marker for empty group set member */
124 #define	MAXHOSTNAMELEN	256		/* max hostname size */
125 
126 #ifndef NOFILE
127 #define	NOFILE		OPEN_MAX	/* max open files per process */
128 #endif
129 #ifndef MAXUPRC				/* max simultaneous processes */
130 #define	MAXUPRC		CHILD_MAX	/* POSIX 1003.1-compliant default */
131 #else
132 #if (MAXUPRC - 0) < CHILD_MAX
133 #error MAXUPRC less than CHILD_MAX.  See options(4) for details.
134 #endif /* (MAXUPRC - 0) < CHILD_MAX */
135 #endif /* !defined(MAXUPRC) */
136 
137 /* Macros for min/max. */
138 #define	MIN(a,b)	((/*CONSTCOND*/(a)<(b))?(a):(b))
139 #define	MAX(a,b)	((/*CONSTCOND*/(a)>(b))?(a):(b))
140 
141 /* More types and definitions used throughout the kernel. */
142 #ifdef _KERNEL
143 #include <sys/cdefs.h>
144 #include <sys/errno.h>
145 #include <sys/time.h>
146 #include <sys/resource.h>
147 #include <sys/ucred.h>
148 #include <sys/uio.h>
149 #include <uvm/uvm_param.h>
150 #ifndef NPROC
151 #define	NPROC	(20 + 16 * MAXUSERS)
152 #endif
153 #ifndef NTEXT
154 #define	NTEXT	(80 + NPROC / 8)		/* actually the object cache */
155 #endif
156 #ifndef NVNODE
157 #define	NVNODE	(NPROC + NTEXT + 100)
158 #define	NVNODE_IMPLICIT
159 #endif
160 #ifndef VNODE_KMEM_MAXPCT
161 #define	VNODE_KMEM_MAXPCT	60
162 #endif
163 #ifndef BUFCACHE_VA_MAXPCT
164 #define	BUFCACHE_VA_MAXPCT	20
165 #endif
166 #define	VNODE_COST	2048			/* assumed space in bytes */
167 #endif /* _KERNEL */
168 
169 /* Signals. */
170 #include <sys/signal.h>
171 
172 /* Machine type dependent parameters. */
173 #include <machine/param.h>
174 #include <machine/limits.h>
175 
176 /* pages ("clicks") to disk blocks */
177 #define	ctod(x)		((x) << (PGSHIFT - DEV_BSHIFT))
178 #define	dtoc(x)		((x) >> (PGSHIFT - DEV_BSHIFT))
179 
180 /* bytes to pages */
181 #define	ctob(x)		((x) << PGSHIFT)
182 #define	btoc(x)		(((x) + PGOFSET) >> PGSHIFT)
183 
184 /* bytes to disk blocks */
185 #define	dbtob(x)	((x) << DEV_BSHIFT)
186 #define	btodb(x)	((x) >> DEV_BSHIFT)
187 
188 #ifndef COHERENCY_UNIT
189 #define	COHERENCY_UNIT		64
190 #endif
191 #ifndef CACHE_LINE_SIZE
192 #define	CACHE_LINE_SIZE		64
193 #endif
194 #ifndef MAXCPUS
195 #define	MAXCPUS			32
196 #endif
197 #ifndef MAX_LWP_PER_PROC
198 #define	MAX_LWP_PER_PROC	8000
199 #endif
200 
201 /*
202  * Stack macros.  On most architectures, the stack grows down,
203  * towards lower addresses; it is the rare architecture where
204  * it grows up, towards higher addresses.
205  *
206  * STACK_GROW and STACK_SHRINK adjust a stack pointer by some
207  * size, no questions asked.  STACK_ALIGN aligns a stack pointer.
208  *
209  * STACK_ALLOC returns a pointer to allocated stack space of
210  * some size; given such a pointer and a size, STACK_MAX gives
211  * the maximum (in the "maxsaddr" sense) stack address of the
212  * allocated memory.
213  */
214 #if defined(_KERNEL) || defined(__EXPOSE_STACK)
215 
216 #ifndef STACK_ALIGNBYTES
217 #define STACK_ALIGNBYTES	__ALIGNBYTES
218 #endif
219 
220 #ifdef __MACHINE_STACK_GROWS_UP
221 #define	STACK_GROW(sp, _size)		(((char *)(void *)(sp)) + (_size))
222 #define	STACK_SHRINK(sp, _size)		(((char *)(void *)(sp)) - (_size))
223 #define	STACK_ALIGN(sp, bytes)	\
224 	((char *)((((unsigned long)(sp)) + (bytes)) & ~(bytes)))
225 #define	STACK_ALLOC(sp, _size)		((char *)(void *)(sp))
226 #define	STACK_MAX(p, _size)		(((char *)(void *)(p)) + (_size))
227 #else
228 #define	STACK_GROW(sp, _size)		(((char *)(void *)(sp)) - (_size))
229 #define	STACK_SHRINK(sp, _size)		(((char *)(void *)(sp)) + (_size))
230 #define	STACK_ALIGN(sp, bytes)	\
231 	((char *)(((unsigned long)(sp)) & ~(bytes)))
232 #define	STACK_ALLOC(sp, _size)		(((char *)(void *)(sp)) - (_size))
233 #define	STACK_MAX(p, _size)		((char *)(void *)(p))
234 #endif
235 #define	STACK_LEN_ALIGN(len, bytes)	(((len) + (bytes)) & ~(bytes))
236 
237 #endif /* defined(_KERNEL) || defined(__EXPOSE_STACK) */
238 
239 /*
240  * Round p (pointer or byte index) up to a correctly-aligned value for all
241  * data types (int, long, ...).   The result is u_int and must be cast to
242  * any desired pointer type.
243  *
244  * ALIGNED_POINTER is a boolean macro that checks whether an address
245  * is valid to fetch data elements of type t from on this architecture.
246  * This does not reflect the optimal alignment, just the possibility
247  * (within reasonable limits).
248  *
249  */
250 #define ALIGNBYTES	__ALIGNBYTES
251 #ifndef ALIGN
252 #define	ALIGN(p)		(((uintptr_t)(p) + ALIGNBYTES) & ~ALIGNBYTES)
253 #endif
254 #ifndef ALIGNED_POINTER
255 #define	ALIGNED_POINTER(p,t)	((((uintptr_t)(p)) & (sizeof(t) - 1)) == 0)
256 #endif
257 
258 /*
259  * Historic priority levels.  These are meaningless and remain only
260  * for source compatibility.  Do not use in new code.
261  */
262 #define	PSWP	0
263 #define	PVM	4
264 #define	PINOD	8
265 #define	PRIBIO	16
266 #define	PVFS	20
267 #define	PZERO	22
268 #define	PSOCK	24
269 #define	PWAIT	32
270 #define	PLOCK	36
271 #define	PPAUSE	40
272 #define	PUSER	50
273 #define	MAXPRI	127
274 
275 #define	PCATCH		0x100	/* OR'd with pri for tsleep to check signals */
276 #define	PNORELOCK	0x200	/* OR'd with pri for tsleep to not relock */
277 
278 /*
279  * New priority levels.
280  */
281 #define	PRI_COUNT		224
282 #define	PRI_NONE		(-1)
283 
284 #define	PRI_KERNEL_RT		192
285 #define	NPRI_KERNEL_RT		32
286 #define	MAXPRI_KERNEL_RT	(PRI_KERNEL_RT + NPRI_KERNEL_RT - 1)
287 
288 #define	PRI_USER_RT		128
289 #define	NPRI_USER_RT		64
290 #define	MAXPRI_USER_RT		(PRI_USER_RT + NPRI_USER_RT - 1)
291 
292 #define	PRI_KTHREAD		96
293 #define	NPRI_KTHREAD		32
294 #define	MAXPRI_KTHREAD		(PRI_KTHREAD + NPRI_KTHREAD - 1)
295 
296 #define	PRI_KERNEL		64
297 #define	NPRI_KERNEL		32
298 #define	MAXPRI_KERNEL		(PRI_KERNEL + NPRI_KERNEL - 1)
299 
300 #define	PRI_USER		0
301 #define	NPRI_USER		64
302 #define	MAXPRI_USER		(PRI_USER + NPRI_USER - 1)
303 
304 /* Priority range used by POSIX real-time features */
305 #define	SCHED_PRI_MIN		0
306 #define	SCHED_PRI_MAX		63
307 
308 /*
309  * Kernel thread priorities.
310  */
311 #define	PRI_SOFTSERIAL	MAXPRI_KERNEL_RT
312 #define	PRI_SOFTNET	(MAXPRI_KERNEL_RT - schedppq * 1)
313 #define	PRI_SOFTBIO	(MAXPRI_KERNEL_RT - schedppq * 2)
314 #define	PRI_SOFTCLOCK	(MAXPRI_KERNEL_RT - schedppq * 3)
315 
316 #define	PRI_XCALL	MAXPRI_KTHREAD
317 #define	PRI_PGDAEMON	(MAXPRI_KTHREAD - schedppq * 1)
318 #define	PRI_VM		(MAXPRI_KTHREAD - schedppq * 2)
319 #define	PRI_IOFLUSH	(MAXPRI_KTHREAD - schedppq * 3)
320 #define	PRI_BIO		(MAXPRI_KTHREAD - schedppq * 4)
321 
322 #define	PRI_IDLE	PRI_USER
323 
324 /*
325  * Miscellaneous.
326  */
327 #define	NBPW	sizeof(int)	/* number of bytes per word (integer) */
328 
329 #define	CMASK	022		/* default file mask: S_IWGRP|S_IWOTH */
330 #define	NODEV	(dev_t)(-1)	/* non-existent device */
331 
332 /*
333  * File system parameters and macros.
334  *
335  * The file system is made out of blocks of at most MAXBSIZE units, with
336  * smaller units (fragments) only in the last direct block.  MAXBSIZE
337  * primarily determines the size of buffers in the buffer pool.  It may be
338  * made larger without any effect on existing file systems; however making
339  * it smaller may make some file systems unmountable.
340  */
341 #ifndef MAXBSIZE				/* XXX */
342 #define	MAXBSIZE	MAXPHYS
343 #endif
344 #define	MAXFRAG 	8
345 
346 /*
347  * MAXPATHLEN defines the longest permissible path length after expanding
348  * symbolic links. It is used to allocate a temporary buffer from the buffer
349  * pool in which to do the name expansion, hence should be a power of two,
350  * and must be less than or equal to MAXBSIZE.  MAXSYMLINKS defines the
351  * maximum number of symbolic links that may be expanded in a path name.
352  * It should be set high enough to allow all legitimate uses, but halt
353  * infinite loops reasonably quickly.
354  *
355  * MAXSYMLINKS should be >= _POSIX_SYMLOOP_MAX (see <limits.h>)
356  */
357 #define	MAXPATHLEN	PATH_MAX
358 #define	MAXSYMLINKS	32
359 
360 /*
361  * This is the maximum individual filename component length enforced by
362  * namei. Filesystems cannot exceed this limit. The upper bound for that
363  * limit is NAME_MAX. We don't bump it for now, for compatibility with
364  * old binaries during the time where MAXPATHLEN was 511 and NAME_MAX was
365  * 255
366  */
367 #define	KERNEL_NAME_MAX	255
368 
369 /* Bit map related macros. */
370 #define	setbit(a,i)	((a)[(i)/NBBY] |= 1<<((i)%NBBY))
371 #define	clrbit(a,i)	((a)[(i)/NBBY] &= ~(1<<((i)%NBBY)))
372 #define	isset(a,i)	((a)[(i)/NBBY] & (1<<((i)%NBBY)))
373 #define	isclr(a,i)	(((a)[(i)/NBBY] & (1<<((i)%NBBY))) == 0)
374 
375 /* Macros for counting and rounding. */
376 #ifndef howmany
377 #define	howmany(x, y)	(((x)+((y)-1))/(y))
378 #endif
379 #define	roundup(x, y)	((((x)+((y)-1))/(y))*(y))
380 #define	rounddown(x,y)	(((x)/(y))*(y))
381 
382 /*
383  * Rounding to powers of two.  The naive definitions of roundup2 and
384  * rounddown2,
385  *
386  *	#define	roundup2(x,m)	(((x) + ((m) - 1)) & ~((m) - 1))
387  *	#define	rounddown2(x,m)	((x) & ~((m) - 1)),
388  *
389  * exhibit a quirk of integer arithmetic in C because the complement
390  * happens in the type of m, not in the type of x.  So if unsigned int
391  * is 32-bit, and m is an unsigned int while x is a uint64_t, then
392  * roundup2 and rounddown2 would have the unintended effect of clearing
393  * the upper 32 bits of the result(!).  These definitions avoid the
394  * pitfalls of C arithmetic depending on the types of x and m, and
395  * additionally avoid multiply evaluating their arguments.
396  */
397 #define	roundup2(x,m)	((((x) - 1) | ((m) - 1)) + 1)
398 #define	rounddown2(x,m)	((x) & ~((__typeof__(x))((m) - 1)))
399 
400 #define	powerof2(x)	((((x)-1)&(x))==0)
401 
402 /*
403  * Constants for setting the parameters of the kernel memory allocator.
404  *
405  * 2 ** MINBUCKET is the smallest unit of memory that will be
406  * allocated. It must be at least large enough to hold a pointer.
407  *
408  * Units of memory less or equal to MAXALLOCSAVE will permanently
409  * allocate physical memory; requests for these size pieces of
410  * memory are quite fast. Allocations greater than MAXALLOCSAVE must
411  * always allocate and free physical memory; requests for these
412  * size allocations should be done infrequently as they will be slow.
413  *
414  * Constraints: NBPG <= MAXALLOCSAVE <= 2 ** (MINBUCKET + 14), and
415  * MAXALLOCSAVE must be a power of two.
416  */
417 #ifdef _LP64
418 #define	MINBUCKET	5		/* 5 => min allocation of 32 bytes */
419 #else
420 #define	MINBUCKET	4		/* 4 => min allocation of 16 bytes */
421 #endif
422 #define	MAXALLOCSAVE	(2 * NBPG)
423 
424 /*
425  * Scale factor for scaled integers used to count %cpu time and load avgs.
426  *
427  * The number of CPU `tick's that map to a unique `%age' can be expressed
428  * by the formula (1 / (2 ^ (FSHIFT - 11))).  The maximum load average that
429  * can be calculated (assuming 32 bits) can be closely approximated using
430  * the formula (2 ^ (2 * (16 - FSHIFT))) for (FSHIFT < 15).
431  *
432  * For the scheduler to maintain a 1:1 mapping of CPU `tick' to `%age',
433  * FSHIFT must be at least 11; this gives us a maximum load avg of ~1024.
434  */
435 #define	FSHIFT	11		/* bits to right of fixed binary point */
436 #define	FSCALE	(1<<FSHIFT)
437 
438 /*
439  * The time for a process to be blocked before being very swappable.
440  * This is a number of seconds which the system takes as being a non-trivial
441  * amount of real time.  You probably shouldn't change this;
442  * it is used in subtle ways (fractions and multiples of it are, that is, like
443  * half of a ``long time'', almost a long time, etc.)
444  * It is related to human patience and other factors which don't really
445  * change over time.
446  */
447 #define        MAXSLP          20
448 
449 /*
450  * Defaults for Unified Buffer Cache parameters.
451  * These may be overridden in <machine/param.h>.
452  */
453 
454 #ifndef UBC_WINSHIFT
455 #define	UBC_WINSHIFT	13
456 #endif
457 #ifndef UBC_NWINS
458 #define	UBC_NWINS	1024
459 #endif
460 
461 #ifdef _KERNEL
462 /*
463  * macro to convert from milliseconds to hz without integer overflow
464  * Default version using only 32bits arithmetics.
465  * 64bit port can define 64bit version in their <machine/param.h>
466  * 0x20000 is safe for hz < 20000
467  */
468 #ifndef mstohz
469 #define mstohz(ms) \
470 	(__predict_false((ms) >= 0x20000) ? \
471 	    ((ms +0u) / 1000u) * hz : \
472 	    ((ms +0u) * hz) / 1000u)
473 #endif
474 #ifndef hztoms
475 #define hztoms(t) \
476 	(__predict_false((t) >= 0x20000) ? \
477 	    ((t +0u) / hz) * 1000u : \
478 	    ((t +0u) * 1000u) / hz)
479 #endif
480 
481 extern const int schedppq;
482 extern size_t coherency_unit;
483 
484 #endif /* _KERNEL */
485 
486 /*
487  * Minimum alignment of "struct lwp" needed by the architecture.
488  * This counts when packing a lock byte into a word alongside a
489  * pointer to an LWP.
490  */
491 #ifndef MIN_LWP_ALIGNMENT
492 #define	MIN_LWP_ALIGNMENT	32
493 #endif
494 #endif /* !__ASSEMBLER__ */
495 
496 #endif /* !_SYS_PARAM_H_ */
497