xref: /illumos-gate/usr/src/uts/common/conf/param.c (revision 46b592853d0f4f11781b6b0a7533f267c6aee132)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #include <sys/types.h>
27 #include <sys/time.h>
28 #include <sys/param.h>
29 #include <sys/systm.h>
30 #include <sys/signal.h>
31 #include <sys/sysmacros.h>
32 #include <sys/cmn_err.h>
33 #include <sys/user.h>
34 #include <sys/proc.h>
35 #include <sys/task.h>
36 #include <sys/project.h>
37 #include <sys/klwp.h>
38 #include <sys/vnode.h>
39 #include <sys/file.h>
40 #include <sys/fcntl.h>
41 #include <sys/flock.h>
42 #include <sys/var.h>
43 #include <sys/stream.h>
44 #include <sys/strsubr.h>
45 #include <sys/conf.h>
46 #include <sys/class.h>
47 #include <sys/ts.h>
48 #include <sys/rt.h>
49 #include <sys/exec.h>
50 #include <sys/exechdr.h>
51 #include <sys/buf.h>
52 #include <sys/resource.h>
53 #include <vm/seg.h>
54 #include <vm/pvn.h>
55 #include <vm/seg_kmem.h>
56 #include <sys/vmparam.h>
57 #include <sys/machparam.h>
58 #include <sys/utsname.h>
59 #include <sys/kmem.h>
60 #include <sys/stack.h>
61 #include <sys/modctl.h>
62 #include <sys/fdbuffer.h>
63 #include <sys/cyclic_impl.h>
64 #include <sys/disp.h>
65 #include <sys/tuneable.h>
66 #include <sys/systeminfo.h>
67 
68 #include <sys/vmem.h>
69 #include <sys/clock.h>
70 #include <sys/serializer.h>
71 
72 /*
73  * The following few lines describe generic things that must be compiled
74  * into the booted executable (unix) rather than genunix or any other
75  * module because they're required by crash dump readers, etc.
76  */
77 struct modctl modules;		/* head of linked list of modules */
78 char *default_path;		/* default module loading path */
79 struct swapinfo *swapinfo;	/* protected by the swapinfo_lock */
80 proc_t *practive;		/* active process list */
81 uint_t nproc;			/* current number of processes */
82 proc_t p0;			/* process 0 */
83 struct plock p0lock;		/* p0's p_lock */
84 klwp_t lwp0;			/* t0's lwp */
85 task_t *task0p;			/* task 0 */
86 kproject_t *proj0p;		/* location of project 0 */
87 
88 /*
89  * The following are "implementation architecture" dependent constants made
90  * available here in the form of initialized data for use by "implementation
91  * architecture" independent modules. See machparam.h.
92  */
93 const unsigned long	_pagesize	= (unsigned long)PAGESIZE;
94 const unsigned int	_pageshift	= (unsigned int)PAGESHIFT;
95 const unsigned long	_pageoffset	= (unsigned long)PAGEOFFSET;
96 /*
97  * XXX - This value pagemask has to be a 64bit size because
98  * large file support uses this mask on offsets which are 64 bit size.
99  * using unsigned leaves the higher 32 bits value as zero thus
100  * corrupting offset calculations in the file system and VM.
101  */
102 const u_longlong_t	_pagemask	= (u_longlong_t)PAGEMASK;
103 const unsigned long	_mmu_pagesize	= (unsigned long)MMU_PAGESIZE;
104 const unsigned int	_mmu_pageshift	= (unsigned int)MMU_PAGESHIFT;
105 const unsigned long	_mmu_pageoffset	= (unsigned long)MMU_PAGEOFFSET;
106 const unsigned long	_mmu_pagemask	= (unsigned long)MMU_PAGEMASK;
107 uintptr_t		_kernelbase	= (uintptr_t)KERNELBASE;
108 uintptr_t		_userlimit	= (uintptr_t)USERLIMIT;
109 uintptr_t		_userlimit32	= (uintptr_t)USERLIMIT32;
110 const uintptr_t		_argsbase	= (uintptr_t)ARGSBASE;
111 const unsigned int	_diskrpm	= (unsigned int)DISKRPM;
112 const unsigned long	_pgthresh	= (unsigned long)PGTHRESH;
113 const unsigned int	_maxslp		= (unsigned int)MAXSLP;
114 const unsigned long	_maxhandspreadpages = (unsigned long)MAXHANDSPREADPAGES;
115 const int		_ncpu 		= (int)NCPU;
116 const unsigned long	_defaultstksz	= (unsigned long)DEFAULTSTKSZ;
117 const unsigned int	_nbpg		= (unsigned int)MMU_PAGESIZE;
118 
119 /*
120  * System parameter formulae.
121  *
122  * This file is copied into each directory where we compile
123  * the kernel; it should be modified there to suit local taste
124  * if necessary.
125  */
126 
127 /*
128  * Default hz is 100, but if we set hires_tick we get higher resolution
129  * clock behavior (currently defined to be 1000 hz).  Higher values seem
130  * to work, but are not supported.
131  *
132  * If we do decide to play with higher values, remember that hz should
133  * satisfy the following constraints to avoid integer round-off problems:
134  *
135  * (1) hz should be in the range 100 <= hz <= MICROSEC.  If hz exceeds
136  *     MICROSEC, usec_per_tick will be zero and lots of stuff will break.
137  *     Similarly, if hz < 100 then hz / 100 == 0 and stuff will break.
138  *
139  * (2) If hz <= 1000, it should be both a multiple of 100 and a
140  *	divisor of 1000.
141  *
142  * (3) If hz > 1000, it should be both a multiple of 1000 and a
143  *	divisor of MICROSEC.
144  *
145  * Thus the only reasonable values of hz (i.e. the values that won't
146  * cause roundoff error) are: 100, 200, 500, 1000, 2000, 4000, 5000,
147  * 8000, 10000, 20000, 25000, 40000, 50000, 100000, 125000, 200000,
148  * 250000, 500000, 1000000.  As of this writing (1996) a clock rate
149  * of more than about 10 kHz seems utterly ridiculous, although
150  * this observation will no doubt seem quaintly amusing one day.
151  */
152 int hz = 100;
153 int hires_hz = 1000;
154 int hires_tick = 0;
155 int cpu_decay_factor = 10;	/* this is no longer tied to clock */
156 int tick_per_msec;	/* clock ticks per millisecond (zero if hz < 1000) */
157 int msec_per_tick;	/* millseconds per clock tick (zero if hz > 1000) */
158 int usec_per_tick;	/* microseconds per clock tick */
159 int nsec_per_tick;	/* nanoseconds per clock tick */
160 int max_hres_adj;	/* maximum adjustment of hrtime per tick */
161 
162 /*
163  * Setting "snooping" to a non-zero value will cause a deadman panic if
164  * snoop_interval microseconds elapse without lbolt increasing.  The default
165  * snoop_interval is 50 seconds.
166  */
167 #define	SNOOP_INTERVAL_MIN	(MICROSEC)
168 #define	SNOOP_INTERVAL_DEFAULT	(50 * MICROSEC)
169 
170 int snooping = 0;
171 uint_t snoop_interval = SNOOP_INTERVAL_DEFAULT;
172 
173 /*
174  * Tables of initialization functions, called from main().
175  */
176 
177 extern void system_taskq_init(void);
178 extern void binit(void);
179 extern void space_init(void);
180 extern void dnlc_init(void);
181 extern void vfsinit(void);
182 extern void finit(void);
183 extern void strinit(void);
184 extern void flk_init(void);
185 extern void ftrace_init(void);
186 extern void softcall_init(void);
187 extern void ttyinit(void);
188 extern void schedctl_init(void);
189 extern void deadman_init(void);
190 extern void clock_timer_init(void);
191 extern void clock_realtime_init(void);
192 extern void clock_highres_init(void);
193 extern void clock_tick_mp_init(void);
194 extern void callout_mp_init(void);
195 extern void cpu_seq_tbl_init(void);
196 
197 void	(*init_tbl[])(void) = {
198 	system_taskq_init,
199 	binit,
200 	space_init,
201 	dnlc_init,
202 	vfsinit,
203 	finit,
204 	strinit,
205 	serializer_init,
206 	softcall_init,
207 	ttyinit,
208 	as_init,
209 	pvn_init,
210 	anon_init,
211 	segvn_init,
212 	flk_init,
213 	cpu_seq_tbl_init,
214 	schedctl_init,
215 	fdb_init,
216 	deadman_init,
217 	clock_timer_init,
218 	clock_realtime_init,
219 	clock_highres_init,
220 	0
221 };
222 
223 
224 #if defined(__sparc)
225 	extern void siron_mp_init();
226 #endif
227 
228 /*
229  * Any per cpu resources should be initialized via
230  * an entry in mp_init_tbl().
231  */
232 void	(*mp_init_tbl[])(void) = {
233 	ftrace_init,
234 	cyclic_mp_init,
235 #if defined(__sparc)
236 	siron_mp_init,
237 #endif
238 	clock_tick_mp_init,
239 	callout_mp_init,
240 	0
241 };
242 
243 int maxusers;		/* kitchen-sink knob for dynamic configuration */
244 
245 /*
246  * pidmax -- highest pid value assigned by the system
247  * Settable in /etc/system
248  */
249 int pidmax = DEFAULT_MAXPID;
250 
251 /*
252  * jump_pid - if set, this value is where pid numbers should start
253  * after the first few system pids (0-3) are used.  If 0, pids are
254  * chosen in the usual way. This variable can be used to quickly
255  * create large pids (by setting it to 100000, for example). pids
256  * less than this value will never be chosen.
257  */
258 pid_t jump_pid = DEFAULT_JUMPPID;
259 
260 /*
261  * autoup -- used in struct var for dynamic config of the age a delayed-write
262  * buffer must be in seconds before bdflush will write it out.
263  */
264 #define	DEFAULT_AUTOUP	30
265 int autoup = DEFAULT_AUTOUP;
266 
267 /*
268  * bufhwm -- tuneable variable for struct var for v_bufhwm.
269  * high water mark for buffer cache mem usage in units of K bytes.
270  *
271  * bufhwm_pct -- ditto, but given in % of physmem.
272  */
273 int bufhwm = 0;
274 int bufhwm_pct = 0;
275 
276 /*
277  * Process table.
278  */
279 int maxpid;
280 int max_nprocs;		/* set in param_init() */
281 int maxuprc;		/* set in param_init() */
282 int reserved_procs;
283 int nthread = 1;
284 
285 /*
286  * UFS tunables
287  */
288 int ufs_ninode;		/* declared here due to backwards compatibility */
289 int ndquot;		/* declared here due to backwards compatibility */
290 
291 /*
292  * Exec switch table. This is used by the generic exec module
293  * to switch out to the desired executable type, based on the
294  * magic number. The currently supported types are ELF, a.out
295  * (both NMAGIC and ZMAGIC), interpreter (#!) files,
296  * and Java executables.
297  */
298 /*
299  * Magic numbers
300  */
301 short elfmagic = 0x7f45;
302 short intpmagic = 0x2321;
303 short jmagic = 0x504b;
304 
305 #if defined(__sparc)
306 short aout_nmagic = NMAGIC;
307 short aout_zmagic = ZMAGIC;
308 short aout_omagic = OMAGIC;
309 #endif
310 short nomagic = 0;
311 
312 /*
313  * Magic strings
314  */
315 #define	ELF32MAGIC_STRING	"\x7f""ELF\x1"
316 #define	ELF64MAGIC_STRING	"\x7f""ELF\x2"
317 #define	INTPMAGIC_STRING	"#!"
318 #define	JAVAMAGIC_STRING	"PK\003\004"
319 #define	AOUT_OMAGIC_STRING	"\x1""\x07"	/* 0407 */
320 #define	AOUT_NMAGIC_STRING	"\x1""\x08"	/* 0410 */
321 #define	AOUT_ZMAGIC_STRING	"\x1""\x0b"	/* 0413 */
322 #define	NOMAGIC_STRING		""
323 
324 #define	SHBIN_CNTL(x)	((x)&037)
325 #define	SHBINMAGIC_STRING {SHBIN_CNTL('k'), SHBIN_CNTL('s'), SHBIN_CNTL('h'), 0}
326 #define	SHBINMAGIC_LEN	4
327 
328 char elf32magicstr[] = ELF32MAGIC_STRING;
329 char elf64magicstr[] = ELF64MAGIC_STRING;
330 char intpmagicstr[] = INTPMAGIC_STRING;
331 char shbinmagicstr[] = SHBINMAGIC_STRING;
332 char javamagicstr[] = JAVAMAGIC_STRING;
333 #if defined(__sparc)
334 char aout_nmagicstr[] = AOUT_NMAGIC_STRING;
335 char aout_zmagicstr[] = AOUT_ZMAGIC_STRING;
336 char aout_omagicstr[] = AOUT_OMAGIC_STRING;
337 #endif
338 char nomagicstr[] = NOMAGIC_STRING;
339 
340 char *execswnames[] = {
341 	"elfexec",	/* Elf32 */
342 #ifdef _LP64
343 	"elfexec",	/* Elf64 */
344 #endif
345 	"intpexec",
346 	"shbinexec",
347 	"javaexec",
348 #if defined(__sparc)
349 	"aoutexec",
350 	"aoutexec",
351 	"aoutexec",
352 #endif
353 	NULL,
354 	NULL,
355 	NULL
356 };
357 
358 struct execsw execsw[] = {
359 	{ elf32magicstr, 0, 5, NULL, NULL, NULL },
360 #ifdef _LP64
361 	{ elf64magicstr, 0, 5, NULL, NULL, NULL },
362 #endif
363 	{ intpmagicstr, 0, 2, NULL, NULL, NULL },
364 	{ shbinmagicstr, 0, SHBINMAGIC_LEN, NULL, NULL, NULL },
365 	{ javamagicstr, 0, 4, NULL, NULL, NULL },
366 #if defined(__sparc)
367 	{ aout_zmagicstr, 2, 2, NULL, NULL, NULL },
368 	{ aout_nmagicstr, 2, 2, NULL, NULL, NULL },
369 	{ aout_omagicstr, 2, 2, NULL, NULL, NULL },
370 #endif
371 	{ nomagicstr, 0, 0, NULL, NULL, NULL },
372 	{ nomagicstr, 0, 0, NULL, NULL, NULL },
373 	{ nomagicstr, 0, 0, NULL, NULL, NULL },
374 	{ nomagicstr, 0, 0, NULL, NULL, NULL }
375 };
376 int nexectype = sizeof (execsw) / sizeof (execsw[0]);	/* # of exec types */
377 kmutex_t execsw_lock;	/* Used for allocation of execsw entries */
378 
379 /*
380  * symbols added to make changing max-file-descriptors
381  * simple via /etc/system
382  */
383 #define	RLIM_FD_CUR 0x100
384 #define	RLIM_FD_MAX 0x10000
385 
386 uint_t rlim_fd_cur = RLIM_FD_CUR;
387 uint_t rlim_fd_max = RLIM_FD_MAX;
388 
389 /*
390  * (Default resource limits were formerly declared here, but are now provided by
391  * the more general resource controls framework.)
392  */
393 
394 /*
395  * STREAMS tunables
396  */
397 int	nstrpush = 9;		/* maximum # of modules/drivers on a stream */
398 ssize_t	strctlsz = 1024;	/* maximum size of user-generated M_PROTO */
399 ssize_t	strmsgsz = 0x10000;	/* maximum size of user-generated M_DATA */
400 				/* for `strmsgsz', zero means unlimited */
401 /*
402  * Filesystem tunables
403  */
404 int	rstchown = 1;		/* POSIX_CHOWN_RESTRICTED is enabled */
405 int	ngroups_max = NGROUPS_MAX_DEFAULT;
406 
407 /*
408  * generic scheduling stuff
409  *
410  * Configurable parameters for RT and TS are in the respective
411  * scheduling class modules.
412  */
413 
414 pri_t maxclsyspri = MAXCLSYSPRI;
415 pri_t minclsyspri = MINCLSYSPRI;
416 char sys_name[] = "SYS";
417 
418 extern pri_t sys_init();
419 extern classfuncs_t sys_classfuncs;
420 
421 sclass_t sclass[] = {
422 	{ "SYS",	sys_init,	&sys_classfuncs, STATIC_SCHED, 0 },
423 	{ "",	NULL,	NULL,	NULL, 0 },
424 	{ "",	NULL,	NULL,	NULL, 0 },
425 	{ "",	NULL,	NULL,	NULL, 0 },
426 	{ "",	NULL,	NULL,	NULL, 0 },
427 	{ "",	NULL,	NULL,	NULL, 0 },
428 	{ "",	NULL,	NULL,	NULL, 0 },
429 	{ "",	NULL,	NULL,	NULL, 0 },
430 	{ "",	NULL,	NULL,	NULL, 0 },
431 	{ "",	NULL,	NULL,	NULL, 0 }
432 };
433 
434 int loaded_classes = 1;		/* for loaded classes */
435 kmutex_t class_lock;		/* lock for class[] */
436 
437 int nclass = sizeof (sclass) / sizeof (sclass_t);
438 char initcls[] = "TS";
439 char *defaultclass = initcls;
440 
441 /*
442  * Tunable system parameters.
443  */
444 
445 /*
446  * The integers tune_* are done this way so that the tune
447  * data structure may be "tuned" if necessary from the /etc/system
448  * file. The tune data structure is initialized in param_init();
449  */
450 
451 tune_t tune;
452 
453 /*
454  * If freemem < t_getpgslow, then start to steal pages from processes.
455  */
456 int tune_t_gpgslo = 25;
457 
458 /*
459  * Rate at which fsflush is run, in seconds.
460  */
461 #define	DEFAULT_TUNE_T_FSFLUSHR	1
462 int tune_t_fsflushr = DEFAULT_TUNE_T_FSFLUSHR;
463 
464 /*
465  * The minimum available resident (not swappable) memory to maintain
466  * in order to avoid deadlock.  In pages.
467  */
468 int tune_t_minarmem = 25;
469 
470 /*
471  * The minimum available swappable memory to maintain in order to avoid
472  * deadlock.  In pages.
473  */
474 int tune_t_minasmem = 25;
475 
476 int tune_t_flckrec = 512;	/* max # of active frlocks */
477 
478 /*
479  * Number of currently available pages that cannot be 'locked'
480  * This is set in init_pages_pp_maximum, and must be initialized
481  * to zero here to detect an override in /etc/system
482  */
483 pgcnt_t pages_pp_maximum = 0;
484 
485 int boothowto;			/* boot flags passed to kernel */
486 struct var v;			/* System Configuration Information */
487 
488 /*
489  * System Configuration Information
490  */
491 
492 /*
493  * The physical system's host identifier, expressed as a decimal string.
494  * Code should only directly access this value when writing to it (setting the
495  * physical system's host identifier).  Code that reads the physical system's
496  * host identifier should use zone_get_hostid(NULL) instead.
497  */
498 char hw_serial[HW_HOSTID_LEN] = "0";
499 
500 #if defined(__sparc)
501 
502 /*
503  * On sparc machines, read hw_serial from the firmware at boot time
504  * and simply assert Sun is the hardware provider.  Hmm.
505  */
506 char architecture[] = "sparcv9";
507 char architecture_32[] = "sparc";
508 char hw_provider[] = "Sun_Microsystems";
509 
510 #elif defined(__i386)
511 
512 /*
513  * On x86 machines, read hw_serial, hw_provider and srpc_domain from
514  * /etc/bootrc at boot time.
515  */
516 char architecture[] = "i386";
517 char architecture_32[] = "i386";
518 char hw_provider[SYS_NMLN] = "";
519 
520 #elif defined(__amd64)
521 
522 /*
523  * On amd64 machines, read hw_serial, hw_provider and srpc_domain from
524  * /etc/bootrc at boot time.
525  */
526 char architecture[] = "amd64";
527 char architecture_32[] = "i386";
528 char hw_provider[SYS_NMLN] = "";
529 
530 #else
531 #error "unknown processor architecture"
532 #endif
533 
534 char srpc_domain[SYS_NMLN] = "";
535 char platform[SYS_NMLN] = "";	/* read from the devinfo root node */
536 
537 /* Initialize isa_list */
538 char *isa_list = architecture;
539 
540 static pgcnt_t original_physmem = 0;
541 
542 #define	MIN_DEFAULT_MAXUSERS	8u
543 #define	MAX_DEFAULT_MAXUSERS	2048u
544 #define	MAX_MAXUSERS		4096u
545 
546 void
547 param_preset(void)
548 {
549 	original_physmem = physmem;
550 }
551 
552 void
553 param_calc(int platform_max_nprocs)
554 {
555 	/*
556 	 * Default to about one "user" per megabyte, taking into
557 	 * account both physical and virtual constraints.
558 	 * Note: 2^20 is a meg; shifting right by (20 - PAGESHIFT)
559 	 * converts pages to megs without integer overflow.
560 	 */
561 #if defined(__sparc)
562 	if (physmem > original_physmem) {
563 		physmem = original_physmem;
564 		cmn_err(CE_NOTE, "physmem limited to %ld", physmem);
565 	}
566 #endif
567 	if (maxusers == 0) {
568 		pgcnt_t physmegs = physmem >> (20 - PAGESHIFT);
569 		pgcnt_t virtmegs = vmem_size(heap_arena, VMEM_FREE) >> 20;
570 		maxusers = MIN(MAX(MIN(physmegs, virtmegs),
571 		    MIN_DEFAULT_MAXUSERS), MAX_DEFAULT_MAXUSERS);
572 	}
573 	if (maxusers > MAX_MAXUSERS) {
574 		maxusers = MAX_MAXUSERS;
575 		cmn_err(CE_NOTE, "maxusers limited to %d", MAX_MAXUSERS);
576 	}
577 
578 	if (ngroups_max > NGROUPS_MAX_DEFAULT)
579 		cmn_err(CE_WARN, "ngroups_max of %d > %d, NFS AUTH_SYS will"
580 		    " not work properly", ngroups_max, NGROUPS_MAX_DEFAULT);
581 
582 #ifdef DEBUG
583 	/*
584 	 * The purpose of maxusers is to prevent memory overcommit.
585 	 * DEBUG kernels take more space, so reduce maxusers a bit.
586 	 */
587 	maxusers = (3 * maxusers) / 4;
588 #endif
589 
590 	/*
591 	 * We need to dynamically change any variables now so that
592 	 * the setting of maxusers and pidmax propagate to the other
593 	 * variables that are dependent on them.
594 	 */
595 	if (reserved_procs == 0)
596 		reserved_procs = 5;
597 	if (pidmax < reserved_procs || pidmax > MAX_MAXPID)
598 		maxpid = MAX_MAXPID;
599 	else
600 		maxpid = pidmax;
601 
602 	/*
603 	 * This allows platform-dependent code to constrain the maximum
604 	 * number of processes allowed in case there are e.g. VM limitations
605 	 * with how many contexts are available.
606 	 */
607 	if (max_nprocs == 0)
608 		max_nprocs = (10 + 16 * maxusers);
609 	if (platform_max_nprocs > 0 && max_nprocs > platform_max_nprocs)
610 		max_nprocs = platform_max_nprocs;
611 	if (max_nprocs > maxpid)
612 		max_nprocs = maxpid;
613 
614 	if (maxuprc == 0)
615 		maxuprc = (max_nprocs - reserved_procs);
616 }
617 
618 void
619 param_init(void)
620 {
621 	/*
622 	 * Set each individual element of struct var v to be the
623 	 * default value. This is done this way
624 	 * so that a user can set the assigned integer value in the
625 	 * /etc/system file *IF* tuning is needed.
626 	 */
627 	v.v_proc = max_nprocs;	/* v_proc - max # of processes system wide */
628 	v.v_maxupttl = max_nprocs - reserved_procs;
629 	v.v_maxsyspri = (int)maxclsyspri;  /* max global pri for sysclass */
630 	v.v_maxup = MIN(maxuprc, v.v_maxupttl); /* max procs per user */
631 	v.v_autoup = autoup;	/* v_autoup - delay for delayed writes */
632 
633 	/*
634 	 * Set each individual element of struct tune to be the
635 	 * default value. Each struct element This is done this way
636 	 *  so that a user can set the assigned integer value in the
637 	 * /etc/system file *IF* tuning is needed.
638 	 */
639 	tune.t_gpgslo = tune_t_gpgslo;
640 	tune.t_fsflushr = tune_t_fsflushr;
641 	tune.t_minarmem = tune_t_minarmem;
642 	tune.t_minasmem = tune_t_minasmem;
643 	tune.t_flckrec = tune_t_flckrec;
644 
645 	/*
646 	 * Initialization for file descriptors to correct mistaken settings in
647 	 * /etc/system.  Initialization of limits performed by resource control
648 	 * system.
649 	 */
650 	if (rlim_fd_cur > rlim_fd_max)
651 		rlim_fd_cur = rlim_fd_max;
652 
653 	/*
654 	 * calculations needed if hz was set in /etc/system
655 	 */
656 	if (hires_tick)
657 		hz = hires_hz;
658 
659 	tick_per_msec = hz / MILLISEC;
660 	msec_per_tick = MILLISEC / hz;
661 	usec_per_tick = MICROSEC / hz;
662 	nsec_per_tick = NANOSEC / hz;
663 	max_hres_adj = nsec_per_tick >> ADJ_SHIFT;
664 }
665 
666 /*
667  * Validate tuneable parameters following /etc/system processing,
668  * but prior to param_init().
669  */
670 void
671 param_check(void)
672 {
673 #if defined(__x86)
674 	if (physmem != original_physmem) {
675 		cmn_err(CE_NOTE, "physmem cannot be modified to 0x%lx"
676 		    " via /etc/system. Please use eeprom(1M) instead.",
677 		    physmem);
678 		physmem = original_physmem;
679 	}
680 #endif
681 	if (ngroups_max < NGROUPS_UMIN || ngroups_max > NGROUPS_UMAX)
682 		ngroups_max = NGROUPS_MAX_DEFAULT;
683 
684 	if (autoup <= 0) {
685 		autoup = DEFAULT_AUTOUP;
686 		cmn_err(CE_WARN, "autoup <= 0; defaulting to %d", autoup);
687 	}
688 
689 	if (tune_t_fsflushr <= 0) {
690 		tune_t_fsflushr = DEFAULT_TUNE_T_FSFLUSHR;
691 		cmn_err(CE_WARN, "tune_t_fsflushr <= 0; defaulting to %d",
692 		    tune_t_fsflushr);
693 	}
694 
695 	if (jump_pid < 0 || jump_pid >= pidmax) {
696 		jump_pid = 0;
697 		cmn_err(CE_WARN, "jump_pid < 0 or >= pidmax; ignored");
698 	}
699 
700 	if (snoop_interval < SNOOP_INTERVAL_MIN) {
701 		snoop_interval = SNOOP_INTERVAL_DEFAULT;
702 		cmn_err(CE_WARN, "snoop_interval < minimum (%d); defaulting"
703 		    " to %d", SNOOP_INTERVAL_MIN, SNOOP_INTERVAL_DEFAULT);
704 	}
705 }
706