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/8.1/sys/kern/kern_clock.c 207138 2010-04-24 00:53:41Z attilio $"); 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_lock deadlkres", 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 thread_lock(td); 206 if (TD_ON_LOCK(td)) { 207 208 /* 209 * The thread should be blocked on a 210 * turnstile, simply check if the 211 * turnstile channel is in good state. 212 */ 213 MPASS(td->td_blocked != NULL); 214 215 /* Handle ticks wrap-up. */ 216 if (ticks < td->td_blktick) 217 continue; 218 tticks = ticks - td->td_blktick; 219 thread_unlock(td); 220 if (tticks > blkticks) { 221 222 /* 223 * Accordingly with provided 224 * thresholds, this thread is 225 * stuck for too long on a 226 * turnstile. 227 */ 228 PROC_UNLOCK(p); 229 sx_sunlock(&allproc_lock); 230 panic("%s: possible deadlock detected for %p, blocked for %d ticks\n", 231 __func__, td, tticks); 232 } 233 } else if (TD_IS_SLEEPING(td)) { 234 235 /* Handle ticks wrap-up. */ 236 if (ticks < td->td_blktick) 237 continue; 238 239 /* 240 * Check if the thread is sleeping on a 241 * lock, otherwise skip the check. 242 * Drop the thread lock in order to 243 * avoid a LOR with the sleepqueue 244 * spinlock. 245 */ 246 wchan = td->td_wchan; 247 tticks = ticks - td->td_slptick; 248 thread_unlock(td); 249 slptype = sleepq_type(wchan); 250 if ((slptype == SLEEPQ_SX || 251 slptype == SLEEPQ_LK) && 252 tticks > slpticks) { 253 254 /* 255 * Accordingly with provided 256 * thresholds, this thread is 257 * stuck for too long on a 258 * sleepqueue. 259 * However, being on a 260 * sleepqueue, we might still 261 * check for the blessed 262 * list. 263 */ 264 tryl = 0; 265 for (i = 0; blessed[i] != NULL; 266 i++) { 267 if (!strcmp(blessed[i], 268 td->td_wmesg)) { 269 tryl = 1; 270 break; 271 } 272 } 273 if (tryl != 0) { 274 tryl = 0; 275 continue; 276 } 277 PROC_UNLOCK(p); 278 sx_sunlock(&allproc_lock); 279 panic("%s: possible deadlock detected for %p, blocked for %d ticks\n", 280 __func__, td, tticks); 281 } 282 } else 283 thread_unlock(td); 284 } 285 PROC_UNLOCK(p); 286 } 287 sx_sunlock(&allproc_lock); 288 289 /* Sleep for sleepfreq seconds. */ 290 pause("deadlkres", sleepfreq * hz); 291 } 292 } 293 294 static struct kthread_desc deadlkres_kd = { 295 "deadlkres", 296 deadlkres, 297 (struct thread **)NULL 298 }; 299 300 SYSINIT(deadlkres, SI_SUB_CLOCKS, SI_ORDER_ANY, kthread_start, &deadlkres_kd); 301 302 SYSCTL_NODE(_debug, OID_AUTO, deadlkres, CTLFLAG_RW, 0, "Deadlock resolver"); 303 SYSCTL_INT(_debug_deadlkres, OID_AUTO, slptime_threshold, CTLFLAG_RW, 304 &slptime_threshold, 0, 305 "Number of seconds within is valid to sleep on a sleepqueue"); 306 SYSCTL_INT(_debug_deadlkres, OID_AUTO, blktime_threshold, CTLFLAG_RW, 307 &blktime_threshold, 0, 308 "Number of seconds within is valid to block on a turnstile"); 309 SYSCTL_INT(_debug_deadlkres, OID_AUTO, sleepfreq, CTLFLAG_RW, &sleepfreq, 0, 310 "Number of seconds between any deadlock resolver thread run"); 311 #endif /* DEADLKRES */ 312 313 void 314 read_cpu_time(long *cp_time) 315 { 316 struct pcpu *pc; 317 int i, j; 318 319 /* Sum up global cp_time[]. */ 320 bzero(cp_time, sizeof(long) * CPUSTATES); 321 for (i = 0; i <= mp_maxid; i++) { 322 if (CPU_ABSENT(i)) 323 continue; 324 pc = pcpu_find(i); 325 for (j = 0; j < CPUSTATES; j++) 326 cp_time[j] += pc->pc_cp_time[j]; 327 } 328 } 329 330 #ifdef SW_WATCHDOG 331 #include <sys/watchdog.h> 332 333 static int watchdog_ticks; 334 static int watchdog_enabled; 335 static void watchdog_fire(void); 336 static void watchdog_config(void *, u_int, int *); 337 #endif /* SW_WATCHDOG */ 338 339 /* 340 * Clock handling routines. 341 * 342 * This code is written to operate with two timers that run independently of 343 * each other. 344 * 345 * The main timer, running hz times per second, is used to trigger interval 346 * timers, timeouts and rescheduling as needed. 347 * 348 * The second timer handles kernel and user profiling, 349 * and does resource use estimation. If the second timer is programmable, 350 * it is randomized to avoid aliasing between the two clocks. For example, 351 * the randomization prevents an adversary from always giving up the cpu 352 * just before its quantum expires. Otherwise, it would never accumulate 353 * cpu ticks. The mean frequency of the second timer is stathz. 354 * 355 * If no second timer exists, stathz will be zero; in this case we drive 356 * profiling and statistics off the main clock. This WILL NOT be accurate; 357 * do not do it unless absolutely necessary. 358 * 359 * The statistics clock may (or may not) be run at a higher rate while 360 * profiling. This profile clock runs at profhz. We require that profhz 361 * be an integral multiple of stathz. 362 * 363 * If the statistics clock is running fast, it must be divided by the ratio 364 * profhz/stathz for statistics. (For profiling, every tick counts.) 365 * 366 * Time-of-day is maintained using a "timecounter", which may or may 367 * not be related to the hardware generating the above mentioned 368 * interrupts. 369 */ 370 371 int stathz; 372 int profhz; 373 int profprocs; 374 int ticks; 375 int psratio; 376 377 /* 378 * Initialize clock frequencies and start both clocks running. 379 */ 380 /* ARGSUSED*/ 381 static void 382 initclocks(dummy) 383 void *dummy; 384 { 385 register int i; 386 387 /* 388 * Set divisors to 1 (normal case) and let the machine-specific 389 * code do its bit. 390 */ 391 mtx_init(&time_lock, "time lock", NULL, MTX_SPIN); 392 cpu_initclocks(); 393 394 /* 395 * Compute profhz/stathz, and fix profhz if needed. 396 */ 397 i = stathz ? stathz : hz; 398 if (profhz == 0) 399 profhz = i; 400 psratio = profhz / i; 401 #ifdef SW_WATCHDOG 402 EVENTHANDLER_REGISTER(watchdog_list, watchdog_config, NULL, 0); 403 #endif 404 } 405 406 /* 407 * Each time the real-time timer fires, this function is called on all CPUs. 408 * Note that hardclock() calls hardclock_cpu() for the boot CPU, so only 409 * the other CPUs in the system need to call this function. 410 */ 411 void 412 hardclock_cpu(int usermode) 413 { 414 struct pstats *pstats; 415 struct thread *td = curthread; 416 struct proc *p = td->td_proc; 417 int flags; 418 419 /* 420 * Run current process's virtual and profile time, as needed. 421 */ 422 pstats = p->p_stats; 423 flags = 0; 424 if (usermode && 425 timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value)) { 426 PROC_SLOCK(p); 427 if (itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0) 428 flags |= TDF_ALRMPEND | TDF_ASTPENDING; 429 PROC_SUNLOCK(p); 430 } 431 if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value)) { 432 PROC_SLOCK(p); 433 if (itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0) 434 flags |= TDF_PROFPEND | TDF_ASTPENDING; 435 PROC_SUNLOCK(p); 436 } 437 thread_lock(td); 438 sched_tick(); 439 td->td_flags |= flags; 440 thread_unlock(td); 441 442 #ifdef HWPMC_HOOKS 443 if (PMC_CPU_HAS_SAMPLES(PCPU_GET(cpuid))) 444 PMC_CALL_HOOK_UNLOCKED(curthread, PMC_FN_DO_SAMPLES, NULL); 445 #endif 446 callout_tick(); 447 } 448 449 /* 450 * The real-time timer, interrupting hz times per second. 451 */ 452 void 453 hardclock(int usermode, uintfptr_t pc) 454 { 455 456 atomic_add_int((volatile int *)&ticks, 1); 457 hardclock_cpu(usermode); 458 tc_ticktock(); 459 /* 460 * If no separate statistics clock is available, run it from here. 461 * 462 * XXX: this only works for UP 463 */ 464 if (stathz == 0) { 465 profclock(usermode, pc); 466 statclock(usermode); 467 } 468 #ifdef DEVICE_POLLING 469 hardclock_device_poll(); /* this is very short and quick */ 470 #endif /* DEVICE_POLLING */ 471 #ifdef SW_WATCHDOG 472 if (watchdog_enabled > 0 && --watchdog_ticks <= 0) 473 watchdog_fire(); 474 #endif /* SW_WATCHDOG */ 475 } 476 477 /* 478 * Compute number of ticks in the specified amount of time. 479 */ 480 int 481 tvtohz(tv) 482 struct timeval *tv; 483 { 484 register unsigned long ticks; 485 register long sec, usec; 486 487 /* 488 * If the number of usecs in the whole seconds part of the time 489 * difference fits in a long, then the total number of usecs will 490 * fit in an unsigned long. Compute the total and convert it to 491 * ticks, rounding up and adding 1 to allow for the current tick 492 * to expire. Rounding also depends on unsigned long arithmetic 493 * to avoid overflow. 494 * 495 * Otherwise, if the number of ticks in the whole seconds part of 496 * the time difference fits in a long, then convert the parts to 497 * ticks separately and add, using similar rounding methods and 498 * overflow avoidance. This method would work in the previous 499 * case but it is slightly slower and assumes that hz is integral. 500 * 501 * Otherwise, round the time difference down to the maximum 502 * representable value. 503 * 504 * If ints have 32 bits, then the maximum value for any timeout in 505 * 10ms ticks is 248 days. 506 */ 507 sec = tv->tv_sec; 508 usec = tv->tv_usec; 509 if (usec < 0) { 510 sec--; 511 usec += 1000000; 512 } 513 if (sec < 0) { 514 #ifdef DIAGNOSTIC 515 if (usec > 0) { 516 sec++; 517 usec -= 1000000; 518 } 519 printf("tvotohz: negative time difference %ld sec %ld usec\n", 520 sec, usec); 521 #endif 522 ticks = 1; 523 } else if (sec <= LONG_MAX / 1000000) 524 ticks = (sec * 1000000 + (unsigned long)usec + (tick - 1)) 525 / tick + 1; 526 else if (sec <= LONG_MAX / hz) 527 ticks = sec * hz 528 + ((unsigned long)usec + (tick - 1)) / tick + 1; 529 else 530 ticks = LONG_MAX; 531 if (ticks > INT_MAX) 532 ticks = INT_MAX; 533 return ((int)ticks); 534 } 535 536 /* 537 * Start profiling on a process. 538 * 539 * Kernel profiling passes proc0 which never exits and hence 540 * keeps the profile clock running constantly. 541 */ 542 void 543 startprofclock(p) 544 register struct proc *p; 545 { 546 547 PROC_LOCK_ASSERT(p, MA_OWNED); 548 if (p->p_flag & P_STOPPROF) 549 return; 550 if ((p->p_flag & P_PROFIL) == 0) { 551 p->p_flag |= P_PROFIL; 552 mtx_lock_spin(&time_lock); 553 if (++profprocs == 1) 554 cpu_startprofclock(); 555 mtx_unlock_spin(&time_lock); 556 } 557 } 558 559 /* 560 * Stop profiling on a process. 561 */ 562 void 563 stopprofclock(p) 564 register struct proc *p; 565 { 566 567 PROC_LOCK_ASSERT(p, MA_OWNED); 568 if (p->p_flag & P_PROFIL) { 569 if (p->p_profthreads != 0) { 570 p->p_flag |= P_STOPPROF; 571 while (p->p_profthreads != 0) 572 msleep(&p->p_profthreads, &p->p_mtx, PPAUSE, 573 "stopprof", 0); 574 p->p_flag &= ~P_STOPPROF; 575 } 576 if ((p->p_flag & P_PROFIL) == 0) 577 return; 578 p->p_flag &= ~P_PROFIL; 579 mtx_lock_spin(&time_lock); 580 if (--profprocs == 0) 581 cpu_stopprofclock(); 582 mtx_unlock_spin(&time_lock); 583 } 584 } 585 586 /* 587 * Statistics clock. Updates rusage information and calls the scheduler 588 * to adjust priorities of the active thread. 589 * 590 * This should be called by all active processors. 591 */ 592 void 593 statclock(int usermode) 594 { 595 struct rusage *ru; 596 struct vmspace *vm; 597 struct thread *td; 598 struct proc *p; 599 long rss; 600 long *cp_time; 601 602 td = curthread; 603 p = td->td_proc; 604 605 cp_time = (long *)PCPU_PTR(cp_time); 606 if (usermode) { 607 /* 608 * Charge the time as appropriate. 609 */ 610 td->td_uticks++; 611 if (p->p_nice > NZERO) 612 cp_time[CP_NICE]++; 613 else 614 cp_time[CP_USER]++; 615 } else { 616 /* 617 * Came from kernel mode, so we were: 618 * - handling an interrupt, 619 * - doing syscall or trap work on behalf of the current 620 * user process, or 621 * - spinning in the idle loop. 622 * Whichever it is, charge the time as appropriate. 623 * Note that we charge interrupts to the current process, 624 * regardless of whether they are ``for'' that process, 625 * so that we know how much of its real time was spent 626 * in ``non-process'' (i.e., interrupt) work. 627 */ 628 if ((td->td_pflags & TDP_ITHREAD) || 629 td->td_intr_nesting_level >= 2) { 630 td->td_iticks++; 631 cp_time[CP_INTR]++; 632 } else { 633 td->td_pticks++; 634 td->td_sticks++; 635 if (!TD_IS_IDLETHREAD(td)) 636 cp_time[CP_SYS]++; 637 else 638 cp_time[CP_IDLE]++; 639 } 640 } 641 642 /* Update resource usage integrals and maximums. */ 643 MPASS(p->p_vmspace != NULL); 644 vm = p->p_vmspace; 645 ru = &td->td_ru; 646 ru->ru_ixrss += pgtok(vm->vm_tsize); 647 ru->ru_idrss += pgtok(vm->vm_dsize); 648 ru->ru_isrss += pgtok(vm->vm_ssize); 649 rss = pgtok(vmspace_resident_count(vm)); 650 if (ru->ru_maxrss < rss) 651 ru->ru_maxrss = rss; 652 KTR_POINT2(KTR_SCHED, "thread", sched_tdname(td), "statclock", 653 "prio:%d", td->td_priority, "stathz:%d", (stathz)?stathz:hz); 654 thread_lock_flags(td, MTX_QUIET); 655 sched_clock(td); 656 thread_unlock(td); 657 } 658 659 void 660 profclock(int usermode, uintfptr_t pc) 661 { 662 struct thread *td; 663 #ifdef GPROF 664 struct gmonparam *g; 665 uintfptr_t i; 666 #endif 667 668 td = curthread; 669 if (usermode) { 670 /* 671 * Came from user mode; CPU was in user state. 672 * If this process is being profiled, record the tick. 673 * if there is no related user location yet, don't 674 * bother trying to count it. 675 */ 676 if (td->td_proc->p_flag & P_PROFIL) 677 addupc_intr(td, pc, 1); 678 } 679 #ifdef GPROF 680 else { 681 /* 682 * Kernel statistics are just like addupc_intr, only easier. 683 */ 684 g = &_gmonparam; 685 if (g->state == GMON_PROF_ON && pc >= g->lowpc) { 686 i = PC_TO_I(g, pc); 687 if (i < g->textsize) { 688 KCOUNT(g, i)++; 689 } 690 } 691 } 692 #endif 693 } 694 695 /* 696 * Return information about system clocks. 697 */ 698 static int 699 sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS) 700 { 701 struct clockinfo clkinfo; 702 /* 703 * Construct clockinfo structure. 704 */ 705 bzero(&clkinfo, sizeof(clkinfo)); 706 clkinfo.hz = hz; 707 clkinfo.tick = tick; 708 clkinfo.profhz = profhz; 709 clkinfo.stathz = stathz ? stathz : hz; 710 return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req)); 711 } 712 713 SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate, 714 CTLTYPE_STRUCT|CTLFLAG_RD|CTLFLAG_MPSAFE, 715 0, 0, sysctl_kern_clockrate, "S,clockinfo", 716 "Rate and period of various kernel clocks"); 717 718 #ifdef SW_WATCHDOG 719 720 static void 721 watchdog_config(void *unused __unused, u_int cmd, int *error) 722 { 723 u_int u; 724 725 u = cmd & WD_INTERVAL; 726 if (u >= WD_TO_1SEC) { 727 watchdog_ticks = (1 << (u - WD_TO_1SEC)) * hz; 728 watchdog_enabled = 1; 729 *error = 0; 730 } else { 731 watchdog_enabled = 0; 732 } 733 } 734 735 /* 736 * Handle a watchdog timeout by dumping interrupt information and 737 * then either dropping to DDB or panicking. 738 */ 739 static void 740 watchdog_fire(void) 741 { 742 int nintr; 743 u_int64_t inttotal; 744 u_long *curintr; 745 char *curname; 746 747 curintr = intrcnt; 748 curname = intrnames; 749 inttotal = 0; 750 nintr = eintrcnt - intrcnt; 751 752 printf("interrupt total\n"); 753 while (--nintr >= 0) { 754 if (*curintr) 755 printf("%-12s %20lu\n", curname, *curintr); 756 curname += strlen(curname) + 1; 757 inttotal += *curintr++; 758 } 759 printf("Total %20ju\n", (uintmax_t)inttotal); 760 761 #if defined(KDB) && !defined(KDB_UNATTENDED) 762 kdb_backtrace(); 763 kdb_enter(KDB_WHY_WATCHDOG, "watchdog timeout"); 764 #else 765 panic("watchdog timeout"); 766 #endif 767 } 768 769 #endif /* SW_WATCHDOG */
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