Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_clock.c
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1 /*- 2 * Copyright (c) 1982, 1986, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD: releng/8.2/sys/kern/kern_clock.c 215044 2010-11-09 18:46:09Z jhb $"); 39 40 #include "opt_kdb.h" 41 #include "opt_device_polling.h" 42 #include "opt_hwpmc_hooks.h" 43 #include "opt_ntp.h" 44 #include "opt_watchdog.h" 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/callout.h> 49 #include <sys/kdb.h> 50 #include <sys/kernel.h> 51 #include <sys/kthread.h> 52 #include <sys/ktr.h> 53 #include <sys/lock.h> 54 #include <sys/mutex.h> 55 #include <sys/proc.h> 56 #include <sys/resource.h> 57 #include <sys/resourcevar.h> 58 #include <sys/sched.h> 59 #include <sys/signalvar.h> 60 #include <sys/sleepqueue.h> 61 #include <sys/smp.h> 62 #include <vm/vm.h> 63 #include <vm/pmap.h> 64 #include <vm/vm_map.h> 65 #include <sys/sysctl.h> 66 #include <sys/bus.h> 67 #include <sys/interrupt.h> 68 #include <sys/limits.h> 69 #include <sys/timetc.h> 70 71 #ifdef GPROF 72 #include <sys/gmon.h> 73 #endif 74 75 #ifdef HWPMC_HOOKS 76 #include <sys/pmckern.h> 77 #endif 78 79 #ifdef DEVICE_POLLING 80 extern void hardclock_device_poll(void); 81 #endif /* DEVICE_POLLING */ 82 83 static void initclocks(void *dummy); 84 SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL); 85 86 /* Spin-lock protecting profiling statistics. */ 87 static struct mtx time_lock; 88 89 static int 90 sysctl_kern_cp_time(SYSCTL_HANDLER_ARGS) 91 { 92 int error; 93 long cp_time[CPUSTATES]; 94 #ifdef SCTL_MASK32 95 int i; 96 unsigned int cp_time32[CPUSTATES]; 97 #endif 98 99 read_cpu_time(cp_time); 100 #ifdef SCTL_MASK32 101 if (req->flags & SCTL_MASK32) { 102 if (!req->oldptr) 103 return SYSCTL_OUT(req, 0, sizeof(cp_time32)); 104 for (i = 0; i < CPUSTATES; i++) 105 cp_time32[i] = (unsigned int)cp_time[i]; 106 error = SYSCTL_OUT(req, cp_time32, sizeof(cp_time32)); 107 } else 108 #endif 109 { 110 if (!req->oldptr) 111 return SYSCTL_OUT(req, 0, sizeof(cp_time)); 112 error = SYSCTL_OUT(req, cp_time, sizeof(cp_time)); 113 } 114 return error; 115 } 116 117 SYSCTL_PROC(_kern, OID_AUTO, cp_time, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE, 118 0,0, sysctl_kern_cp_time, "LU", "CPU time statistics"); 119 120 static long empty[CPUSTATES]; 121 122 static int 123 sysctl_kern_cp_times(SYSCTL_HANDLER_ARGS) 124 { 125 struct pcpu *pcpu; 126 int error; 127 int c; 128 long *cp_time; 129 #ifdef SCTL_MASK32 130 unsigned int cp_time32[CPUSTATES]; 131 int i; 132 #endif 133 134 if (!req->oldptr) { 135 #ifdef SCTL_MASK32 136 if (req->flags & SCTL_MASK32) 137 return SYSCTL_OUT(req, 0, sizeof(cp_time32) * (mp_maxid + 1)); 138 else 139 #endif 140 return SYSCTL_OUT(req, 0, sizeof(long) * CPUSTATES * (mp_maxid + 1)); 141 } 142 for (error = 0, c = 0; error == 0 && c <= mp_maxid; c++) { 143 if (!CPU_ABSENT(c)) { 144 pcpu = pcpu_find(c); 145 cp_time = pcpu->pc_cp_time; 146 } else { 147 cp_time = empty; 148 } 149 #ifdef SCTL_MASK32 150 if (req->flags & SCTL_MASK32) { 151 for (i = 0; i < CPUSTATES; i++) 152 cp_time32[i] = (unsigned int)cp_time[i]; 153 error = SYSCTL_OUT(req, cp_time32, sizeof(cp_time32)); 154 } else 155 #endif 156 error = SYSCTL_OUT(req, cp_time, sizeof(long) * CPUSTATES); 157 } 158 return error; 159 } 160 161 SYSCTL_PROC(_kern, OID_AUTO, cp_times, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE, 162 0,0, sysctl_kern_cp_times, "LU", "per-CPU time statistics"); 163 164 #ifdef DEADLKRES 165 static const char *blessed[] = { 166 "getblk", 167 "so_snd_sx", 168 "so_rcv_sx", 169 NULL 170 }; 171 static int slptime_threshold = 1800; 172 static int blktime_threshold = 900; 173 static int sleepfreq = 3; 174 175 static void 176 deadlkres(void) 177 { 178 struct proc *p; 179 struct thread *td; 180 void *wchan; 181 int blkticks, i, slpticks, slptype, tryl, tticks; 182 183 tryl = 0; 184 for (;;) { 185 blkticks = blktime_threshold * hz; 186 slpticks = slptime_threshold * hz; 187 188 /* 189 * Avoid to sleep on the sx_lock in order to avoid a possible 190 * priority inversion problem leading to starvation. 191 * If the lock can't be held after 100 tries, panic. 192 */ 193 if (!sx_try_slock(&allproc_lock)) { 194 if (tryl > 100) 195 panic("%s: possible deadlock detected on allproc_lock\n", 196 __func__); 197 tryl++; 198 pause("allproc", sleepfreq * hz); 199 continue; 200 } 201 tryl = 0; 202 FOREACH_PROC_IN_SYSTEM(p) { 203 PROC_LOCK(p); 204 FOREACH_THREAD_IN_PROC(p, td) { 205 206 /* 207 * Once a thread is found in "interesting" 208 * state a possible ticks wrap-up needs to be 209 * checked. 210 */ 211 thread_lock(td); 212 if (TD_ON_LOCK(td) && ticks < td->td_blktick) { 213 214 /* 215 * The thread should be blocked on a 216 * turnstile, simply check if the 217 * turnstile channel is in good state. 218 */ 219 MPASS(td->td_blocked != NULL); 220 221 tticks = ticks - td->td_blktick; 222 thread_unlock(td); 223 if (tticks > blkticks) { 224 225 /* 226 * Accordingly with provided 227 * thresholds, this thread is 228 * stuck for too long on a 229 * turnstile. 230 */ 231 PROC_UNLOCK(p); 232 sx_sunlock(&allproc_lock); 233 panic("%s: possible deadlock detected for %p, blocked for %d ticks\n", 234 __func__, td, tticks); 235 } 236 } else if (TD_IS_SLEEPING(td) && 237 TD_ON_SLEEPQ(td) && 238 ticks < td->td_blktick) { 239 240 /* 241 * Check if the thread is sleeping on a 242 * lock, otherwise skip the check. 243 * Drop the thread lock in order to 244 * avoid a LOR with the sleepqueue 245 * spinlock. 246 */ 247 wchan = td->td_wchan; 248 tticks = ticks - td->td_slptick; 249 thread_unlock(td); 250 slptype = sleepq_type(wchan); 251 if ((slptype == SLEEPQ_SX || 252 slptype == SLEEPQ_LK) && 253 tticks > slpticks) { 254 255 /* 256 * Accordingly with provided 257 * thresholds, this thread is 258 * stuck for too long on a 259 * sleepqueue. 260 * However, being on a 261 * sleepqueue, we might still 262 * check for the blessed 263 * list. 264 */ 265 tryl = 0; 266 for (i = 0; blessed[i] != NULL; 267 i++) { 268 if (!strcmp(blessed[i], 269 td->td_wmesg)) { 270 tryl = 1; 271 break; 272 } 273 } 274 if (tryl != 0) { 275 tryl = 0; 276 continue; 277 } 278 PROC_UNLOCK(p); 279 sx_sunlock(&allproc_lock); 280 panic("%s: possible deadlock detected for %p, blocked for %d ticks\n", 281 __func__, td, tticks); 282 } 283 } else 284 thread_unlock(td); 285 } 286 PROC_UNLOCK(p); 287 } 288 sx_sunlock(&allproc_lock); 289 290 /* Sleep for sleepfreq seconds. */ 291 pause("-", sleepfreq * hz); 292 } 293 } 294 295 static struct kthread_desc deadlkres_kd = { 296 "deadlkres", 297 deadlkres, 298 (struct thread **)NULL 299 }; 300 301 SYSINIT(deadlkres, SI_SUB_CLOCKS, SI_ORDER_ANY, kthread_start, &deadlkres_kd); 302 303 SYSCTL_NODE(_debug, OID_AUTO, deadlkres, CTLFLAG_RW, 0, "Deadlock resolver"); 304 SYSCTL_INT(_debug_deadlkres, OID_AUTO, slptime_threshold, CTLFLAG_RW, 305 &slptime_threshold, 0, 306 "Number of seconds within is valid to sleep on a sleepqueue"); 307 SYSCTL_INT(_debug_deadlkres, OID_AUTO, blktime_threshold, CTLFLAG_RW, 308 &blktime_threshold, 0, 309 "Number of seconds within is valid to block on a turnstile"); 310 SYSCTL_INT(_debug_deadlkres, OID_AUTO, sleepfreq, CTLFLAG_RW, &sleepfreq, 0, 311 "Number of seconds between any deadlock resolver thread run"); 312 #endif /* DEADLKRES */ 313 314 void 315 read_cpu_time(long *cp_time) 316 { 317 struct pcpu *pc; 318 int i, j; 319 320 /* Sum up global cp_time[]. */ 321 bzero(cp_time, sizeof(long) * CPUSTATES); 322 for (i = 0; i <= mp_maxid; i++) { 323 if (CPU_ABSENT(i)) 324 continue; 325 pc = pcpu_find(i); 326 for (j = 0; j < CPUSTATES; j++) 327 cp_time[j] += pc->pc_cp_time[j]; 328 } 329 } 330 331 #ifdef SW_WATCHDOG 332 #include <sys/watchdog.h> 333 334 static int watchdog_ticks; 335 static int watchdog_enabled; 336 static void watchdog_fire(void); 337 static void watchdog_config(void *, u_int, int *); 338 #endif /* SW_WATCHDOG */ 339 340 /* 341 * Clock handling routines. 342 * 343 * This code is written to operate with two timers that run independently of 344 * each other. 345 * 346 * The main timer, running hz times per second, is used to trigger interval 347 * timers, timeouts and rescheduling as needed. 348 * 349 * The second timer handles kernel and user profiling, 350 * and does resource use estimation. If the second timer is programmable, 351 * it is randomized to avoid aliasing between the two clocks. For example, 352 * the randomization prevents an adversary from always giving up the cpu 353 * just before its quantum expires. Otherwise, it would never accumulate 354 * cpu ticks. The mean frequency of the second timer is stathz. 355 * 356 * If no second timer exists, stathz will be zero; in this case we drive 357 * profiling and statistics off the main clock. This WILL NOT be accurate; 358 * do not do it unless absolutely necessary. 359 * 360 * The statistics clock may (or may not) be run at a higher rate while 361 * profiling. This profile clock runs at profhz. We require that profhz 362 * be an integral multiple of stathz. 363 * 364 * If the statistics clock is running fast, it must be divided by the ratio 365 * profhz/stathz for statistics. (For profiling, every tick counts.) 366 * 367 * Time-of-day is maintained using a "timecounter", which may or may 368 * not be related to the hardware generating the above mentioned 369 * interrupts. 370 */ 371 372 int stathz; 373 int profhz; 374 int profprocs; 375 int ticks; 376 int psratio; 377 378 /* 379 * Initialize clock frequencies and start both clocks running. 380 */ 381 /* ARGSUSED*/ 382 static void 383 initclocks(dummy) 384 void *dummy; 385 { 386 register int i; 387 388 /* 389 * Set divisors to 1 (normal case) and let the machine-specific 390 * code do its bit. 391 */ 392 mtx_init(&time_lock, "time lock", NULL, MTX_SPIN); 393 cpu_initclocks(); 394 395 /* 396 * Compute profhz/stathz, and fix profhz if needed. 397 */ 398 i = stathz ? stathz : hz; 399 if (profhz == 0) 400 profhz = i; 401 psratio = profhz / i; 402 #ifdef SW_WATCHDOG 403 EVENTHANDLER_REGISTER(watchdog_list, watchdog_config, NULL, 0); 404 #endif 405 } 406 407 /* 408 * Each time the real-time timer fires, this function is called on all CPUs. 409 * Note that hardclock() calls hardclock_cpu() for the boot CPU, so only 410 * the other CPUs in the system need to call this function. 411 */ 412 void 413 hardclock_cpu(int usermode) 414 { 415 struct pstats *pstats; 416 struct thread *td = curthread; 417 struct proc *p = td->td_proc; 418 int flags; 419 420 /* 421 * Run current process's virtual and profile time, as needed. 422 */ 423 pstats = p->p_stats; 424 flags = 0; 425 if (usermode && 426 timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value)) { 427 PROC_SLOCK(p); 428 if (itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0) 429 flags |= TDF_ALRMPEND | TDF_ASTPENDING; 430 PROC_SUNLOCK(p); 431 } 432 if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value)) { 433 PROC_SLOCK(p); 434 if (itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0) 435 flags |= TDF_PROFPEND | TDF_ASTPENDING; 436 PROC_SUNLOCK(p); 437 } 438 thread_lock(td); 439 sched_tick(); 440 td->td_flags |= flags; 441 thread_unlock(td); 442 443 #ifdef HWPMC_HOOKS 444 if (PMC_CPU_HAS_SAMPLES(PCPU_GET(cpuid))) 445 PMC_CALL_HOOK_UNLOCKED(curthread, PMC_FN_DO_SAMPLES, NULL); 446 #endif 447 callout_tick(); 448 } 449 450 /* 451 * The real-time timer, interrupting hz times per second. 452 */ 453 void 454 hardclock(int usermode, uintfptr_t pc) 455 { 456 457 atomic_add_int((volatile int *)&ticks, 1); 458 hardclock_cpu(usermode); 459 tc_ticktock(); 460 /* 461 * If no separate statistics clock is available, run it from here. 462 * 463 * XXX: this only works for UP 464 */ 465 if (stathz == 0) { 466 profclock(usermode, pc); 467 statclock(usermode); 468 } 469 #ifdef DEVICE_POLLING 470 hardclock_device_poll(); /* this is very short and quick */ 471 #endif /* DEVICE_POLLING */ 472 #ifdef SW_WATCHDOG 473 if (watchdog_enabled > 0 && --watchdog_ticks <= 0) 474 watchdog_fire(); 475 #endif /* SW_WATCHDOG */ 476 } 477 478 /* 479 * Compute number of ticks in the specified amount of time. 480 */ 481 int 482 tvtohz(tv) 483 struct timeval *tv; 484 { 485 register unsigned long ticks; 486 register long sec, usec; 487 488 /* 489 * If the number of usecs in the whole seconds part of the time 490 * difference fits in a long, then the total number of usecs will 491 * fit in an unsigned long. Compute the total and convert it to 492 * ticks, rounding up and adding 1 to allow for the current tick 493 * to expire. Rounding also depends on unsigned long arithmetic 494 * to avoid overflow. 495 * 496 * Otherwise, if the number of ticks in the whole seconds part of 497 * the time difference fits in a long, then convert the parts to 498 * ticks separately and add, using similar rounding methods and 499 * overflow avoidance. This method would work in the previous 500 * case but it is slightly slower and assumes that hz is integral. 501 * 502 * Otherwise, round the time difference down to the maximum 503 * representable value. 504 * 505 * If ints have 32 bits, then the maximum value for any timeout in 506 * 10ms ticks is 248 days. 507 */ 508 sec = tv->tv_sec; 509 usec = tv->tv_usec; 510 if (usec < 0) { 511 sec--; 512 usec += 1000000; 513 } 514 if (sec < 0) { 515 #ifdef DIAGNOSTIC 516 if (usec > 0) { 517 sec++; 518 usec -= 1000000; 519 } 520 printf("tvotohz: negative time difference %ld sec %ld usec\n", 521 sec, usec); 522 #endif 523 ticks = 1; 524 } else if (sec <= LONG_MAX / 1000000) 525 ticks = (sec * 1000000 + (unsigned long)usec + (tick - 1)) 526 / tick + 1; 527 else if (sec <= LONG_MAX / hz) 528 ticks = sec * hz 529 + ((unsigned long)usec + (tick - 1)) / tick + 1; 530 else 531 ticks = LONG_MAX; 532 if (ticks > INT_MAX) 533 ticks = INT_MAX; 534 return ((int)ticks); 535 } 536 537 /* 538 * Start profiling on a process. 539 * 540 * Kernel profiling passes proc0 which never exits and hence 541 * keeps the profile clock running constantly. 542 */ 543 void 544 startprofclock(p) 545 register struct proc *p; 546 { 547 548 PROC_LOCK_ASSERT(p, MA_OWNED); 549 if (p->p_flag & P_STOPPROF) 550 return; 551 if ((p->p_flag & P_PROFIL) == 0) { 552 p->p_flag |= P_PROFIL; 553 mtx_lock_spin(&time_lock); 554 if (++profprocs == 1) 555 cpu_startprofclock(); 556 mtx_unlock_spin(&time_lock); 557 } 558 } 559 560 /* 561 * Stop profiling on a process. 562 */ 563 void 564 stopprofclock(p) 565 register struct proc *p; 566 { 567 568 PROC_LOCK_ASSERT(p, MA_OWNED); 569 if (p->p_flag & P_PROFIL) { 570 if (p->p_profthreads != 0) { 571 p->p_flag |= P_STOPPROF; 572 while (p->p_profthreads != 0) 573 msleep(&p->p_profthreads, &p->p_mtx, PPAUSE, 574 "stopprof", 0); 575 p->p_flag &= ~P_STOPPROF; 576 } 577 if ((p->p_flag & P_PROFIL) == 0) 578 return; 579 p->p_flag &= ~P_PROFIL; 580 mtx_lock_spin(&time_lock); 581 if (--profprocs == 0) 582 cpu_stopprofclock(); 583 mtx_unlock_spin(&time_lock); 584 } 585 } 586 587 /* 588 * Statistics clock. Updates rusage information and calls the scheduler 589 * to adjust priorities of the active thread. 590 * 591 * This should be called by all active processors. 592 */ 593 void 594 statclock(int usermode) 595 { 596 struct rusage *ru; 597 struct vmspace *vm; 598 struct thread *td; 599 struct proc *p; 600 long rss; 601 long *cp_time; 602 603 td = curthread; 604 p = td->td_proc; 605 606 cp_time = (long *)PCPU_PTR(cp_time); 607 if (usermode) { 608 /* 609 * Charge the time as appropriate. 610 */ 611 td->td_uticks++; 612 if (p->p_nice > NZERO) 613 cp_time[CP_NICE]++; 614 else 615 cp_time[CP_USER]++; 616 } else { 617 /* 618 * Came from kernel mode, so we were: 619 * - handling an interrupt, 620 * - doing syscall or trap work on behalf of the current 621 * user process, or 622 * - spinning in the idle loop. 623 * Whichever it is, charge the time as appropriate. 624 * Note that we charge interrupts to the current process, 625 * regardless of whether they are ``for'' that process, 626 * so that we know how much of its real time was spent 627 * in ``non-process'' (i.e., interrupt) work. 628 */ 629 if ((td->td_pflags & TDP_ITHREAD) || 630 td->td_intr_nesting_level >= 2) { 631 td->td_iticks++; 632 cp_time[CP_INTR]++; 633 } else { 634 td->td_pticks++; 635 td->td_sticks++; 636 if (!TD_IS_IDLETHREAD(td)) 637 cp_time[CP_SYS]++; 638 else 639 cp_time[CP_IDLE]++; 640 } 641 } 642 643 /* Update resource usage integrals and maximums. */ 644 MPASS(p->p_vmspace != NULL); 645 vm = p->p_vmspace; 646 ru = &td->td_ru; 647 ru->ru_ixrss += pgtok(vm->vm_tsize); 648 ru->ru_idrss += pgtok(vm->vm_dsize); 649 ru->ru_isrss += pgtok(vm->vm_ssize); 650 rss = pgtok(vmspace_resident_count(vm)); 651 if (ru->ru_maxrss < rss) 652 ru->ru_maxrss = rss; 653 KTR_POINT2(KTR_SCHED, "thread", sched_tdname(td), "statclock", 654 "prio:%d", td->td_priority, "stathz:%d", (stathz)?stathz:hz); 655 thread_lock_flags(td, MTX_QUIET); 656 sched_clock(td); 657 thread_unlock(td); 658 } 659 660 void 661 profclock(int usermode, uintfptr_t pc) 662 { 663 struct thread *td; 664 #ifdef GPROF 665 struct gmonparam *g; 666 uintfptr_t i; 667 #endif 668 669 td = curthread; 670 if (usermode) { 671 /* 672 * Came from user mode; CPU was in user state. 673 * If this process is being profiled, record the tick. 674 * if there is no related user location yet, don't 675 * bother trying to count it. 676 */ 677 if (td->td_proc->p_flag & P_PROFIL) 678 addupc_intr(td, pc, 1); 679 } 680 #ifdef GPROF 681 else { 682 /* 683 * Kernel statistics are just like addupc_intr, only easier. 684 */ 685 g = &_gmonparam; 686 if (g->state == GMON_PROF_ON && pc >= g->lowpc) { 687 i = PC_TO_I(g, pc); 688 if (i < g->textsize) { 689 KCOUNT(g, i)++; 690 } 691 } 692 } 693 #endif 694 } 695 696 /* 697 * Return information about system clocks. 698 */ 699 static int 700 sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS) 701 { 702 struct clockinfo clkinfo; 703 /* 704 * Construct clockinfo structure. 705 */ 706 bzero(&clkinfo, sizeof(clkinfo)); 707 clkinfo.hz = hz; 708 clkinfo.tick = tick; 709 clkinfo.profhz = profhz; 710 clkinfo.stathz = stathz ? stathz : hz; 711 return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req)); 712 } 713 714 SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate, 715 CTLTYPE_STRUCT|CTLFLAG_RD|CTLFLAG_MPSAFE, 716 0, 0, sysctl_kern_clockrate, "S,clockinfo", 717 "Rate and period of various kernel clocks"); 718 719 #ifdef SW_WATCHDOG 720 721 static void 722 watchdog_config(void *unused __unused, u_int cmd, int *error) 723 { 724 u_int u; 725 726 u = cmd & WD_INTERVAL; 727 if (u >= WD_TO_1SEC) { 728 watchdog_ticks = (1 << (u - WD_TO_1SEC)) * hz; 729 watchdog_enabled = 1; 730 *error = 0; 731 } else { 732 watchdog_enabled = 0; 733 } 734 } 735 736 /* 737 * Handle a watchdog timeout by dumping interrupt information and 738 * then either dropping to DDB or panicking. 739 */ 740 static void 741 watchdog_fire(void) 742 { 743 int nintr; 744 u_int64_t inttotal; 745 u_long *curintr; 746 char *curname; 747 748 curintr = intrcnt; 749 curname = intrnames; 750 inttotal = 0; 751 nintr = eintrcnt - intrcnt; 752 753 printf("interrupt total\n"); 754 while (--nintr >= 0) { 755 if (*curintr) 756 printf("%-12s %20lu\n", curname, *curintr); 757 curname += strlen(curname) + 1; 758 inttotal += *curintr++; 759 } 760 printf("Total %20ju\n", (uintmax_t)inttotal); 761 762 #if defined(KDB) && !defined(KDB_UNATTENDED) 763 kdb_backtrace(); 764 kdb_enter(KDB_WHY_WATCHDOG, "watchdog timeout"); 765 #else 766 panic("watchdog timeout"); 767 #endif 768 } 769 770 #endif /* SW_WATCHDOG */
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