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_timeout.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 * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD: releng/6.0/sys/kern/kern_timeout.c 150591 2005-09-26 19:49:12Z jhb $"); 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/callout.h> 43 #include <sys/condvar.h> 44 #include <sys/kernel.h> 45 #include <sys/ktr.h> 46 #include <sys/lock.h> 47 #include <sys/mutex.h> 48 #include <sys/proc.h> 49 #include <sys/sysctl.h> 50 51 static int avg_depth; 52 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, 53 "Average number of items examined per softclock call. Units = 1/1000"); 54 static int avg_gcalls; 55 SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, 56 "Average number of Giant callouts made per softclock call. Units = 1/1000"); 57 static int avg_mtxcalls; 58 SYSCTL_INT(_debug, OID_AUTO, to_avg_mtxcalls, CTLFLAG_RD, &avg_mtxcalls, 0, 59 "Average number of mtx callouts made per softclock call. Units = 1/1000"); 60 static int avg_mpcalls; 61 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, 62 "Average number of MP callouts made per softclock call. Units = 1/1000"); 63 /* 64 * TODO: 65 * allocate more timeout table slots when table overflows. 66 */ 67 68 /* Exported to machdep.c and/or kern_clock.c. */ 69 struct callout *callout; 70 struct callout_list callfree; 71 int callwheelsize, callwheelbits, callwheelmask; 72 struct callout_tailq *callwheel; 73 int softticks; /* Like ticks, but for softclock(). */ 74 struct mtx callout_lock; 75 76 static struct callout *nextsoftcheck; /* Next callout to be checked. */ 77 78 /** 79 * Locked by callout_lock: 80 * curr_callout - If a callout is in progress, it is curr_callout. 81 * If curr_callout is non-NULL, threads waiting on 82 * callout_wait will be woken up as soon as the 83 * relevant callout completes. 84 * curr_cancelled - Changing to 1 with both callout_lock and c_mtx held 85 * guarantees that the current callout will not run. 86 * The softclock() function sets this to 0 before it 87 * drops callout_lock to acquire c_mtx, and it calls 88 * the handler only if curr_cancelled still 0 when 89 * c_mtx is successfully acquired. 90 * wakeup_ctr - Incremented every time a thread wants to wait 91 * for a callout to complete. Modified only when 92 * curr_callout is non-NULL. 93 * wakeup_needed - If a thread is waiting on callout_wait, then 94 * wakeup_needed is nonzero. Increased only when 95 * cutt_callout is non-NULL. 96 */ 97 static struct callout *curr_callout; 98 static int curr_cancelled; 99 static int wakeup_ctr; 100 static int wakeup_needed; 101 102 /** 103 * Locked by callout_wait_lock: 104 * callout_wait - If wakeup_needed is set, callout_wait will be 105 * triggered after the current callout finishes. 106 * wakeup_done_ctr - Set to the current value of wakeup_ctr after 107 * callout_wait is triggered. 108 */ 109 static struct mtx callout_wait_lock; 110 static struct cv callout_wait; 111 static int wakeup_done_ctr; 112 113 /* 114 * kern_timeout_callwheel_alloc() - kernel low level callwheel initialization 115 * 116 * This code is called very early in the kernel initialization sequence, 117 * and may be called more then once. 118 */ 119 caddr_t 120 kern_timeout_callwheel_alloc(caddr_t v) 121 { 122 /* 123 * Calculate callout wheel size 124 */ 125 for (callwheelsize = 1, callwheelbits = 0; 126 callwheelsize < ncallout; 127 callwheelsize <<= 1, ++callwheelbits) 128 ; 129 callwheelmask = callwheelsize - 1; 130 131 callout = (struct callout *)v; 132 v = (caddr_t)(callout + ncallout); 133 callwheel = (struct callout_tailq *)v; 134 v = (caddr_t)(callwheel + callwheelsize); 135 return(v); 136 } 137 138 /* 139 * kern_timeout_callwheel_init() - initialize previously reserved callwheel 140 * space. 141 * 142 * This code is called just once, after the space reserved for the 143 * callout wheel has been finalized. 144 */ 145 void 146 kern_timeout_callwheel_init(void) 147 { 148 int i; 149 150 SLIST_INIT(&callfree); 151 for (i = 0; i < ncallout; i++) { 152 callout_init(&callout[i], 0); 153 callout[i].c_flags = CALLOUT_LOCAL_ALLOC; 154 SLIST_INSERT_HEAD(&callfree, &callout[i], c_links.sle); 155 } 156 for (i = 0; i < callwheelsize; i++) { 157 TAILQ_INIT(&callwheel[i]); 158 } 159 mtx_init(&callout_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); 160 mtx_init(&callout_wait_lock, "callout_wait_lock", NULL, MTX_DEF); 161 cv_init(&callout_wait, "callout_wait"); 162 } 163 164 /* 165 * The callout mechanism is based on the work of Adam M. Costello and 166 * George Varghese, published in a technical report entitled "Redesigning 167 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 168 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 169 * used in this implementation was published by G. Varghese and T. Lauck in 170 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 171 * the Efficient Implementation of a Timer Facility" in the Proceedings of 172 * the 11th ACM Annual Symposium on Operating Systems Principles, 173 * Austin, Texas Nov 1987. 174 */ 175 176 /* 177 * Software (low priority) clock interrupt. 178 * Run periodic events from timeout queue. 179 */ 180 void 181 softclock(void *dummy) 182 { 183 struct callout *c; 184 struct callout_tailq *bucket; 185 int curticks; 186 int steps; /* #steps since we last allowed interrupts */ 187 int depth; 188 int mpcalls; 189 int mtxcalls; 190 int gcalls; 191 int wakeup_cookie; 192 #ifdef DIAGNOSTIC 193 struct bintime bt1, bt2; 194 struct timespec ts2; 195 static uint64_t maxdt = 36893488147419102LL; /* 2 msec */ 196 static timeout_t *lastfunc; 197 #endif 198 199 #ifndef MAX_SOFTCLOCK_STEPS 200 #define MAX_SOFTCLOCK_STEPS 100 /* Maximum allowed value of steps. */ 201 #endif /* MAX_SOFTCLOCK_STEPS */ 202 203 mpcalls = 0; 204 mtxcalls = 0; 205 gcalls = 0; 206 depth = 0; 207 steps = 0; 208 mtx_lock_spin(&callout_lock); 209 while (softticks != ticks) { 210 softticks++; 211 /* 212 * softticks may be modified by hard clock, so cache 213 * it while we work on a given bucket. 214 */ 215 curticks = softticks; 216 bucket = &callwheel[curticks & callwheelmask]; 217 c = TAILQ_FIRST(bucket); 218 while (c) { 219 depth++; 220 if (c->c_time != curticks) { 221 c = TAILQ_NEXT(c, c_links.tqe); 222 ++steps; 223 if (steps >= MAX_SOFTCLOCK_STEPS) { 224 nextsoftcheck = c; 225 /* Give interrupts a chance. */ 226 mtx_unlock_spin(&callout_lock); 227 ; /* nothing */ 228 mtx_lock_spin(&callout_lock); 229 c = nextsoftcheck; 230 steps = 0; 231 } 232 } else { 233 void (*c_func)(void *); 234 void *c_arg; 235 struct mtx *c_mtx; 236 int c_flags; 237 238 nextsoftcheck = TAILQ_NEXT(c, c_links.tqe); 239 TAILQ_REMOVE(bucket, c, c_links.tqe); 240 c_func = c->c_func; 241 c_arg = c->c_arg; 242 c_mtx = c->c_mtx; 243 c_flags = c->c_flags; 244 if (c->c_flags & CALLOUT_LOCAL_ALLOC) { 245 c->c_func = NULL; 246 c->c_flags = CALLOUT_LOCAL_ALLOC; 247 SLIST_INSERT_HEAD(&callfree, c, 248 c_links.sle); 249 curr_callout = NULL; 250 } else { 251 c->c_flags = 252 (c->c_flags & ~CALLOUT_PENDING); 253 curr_callout = c; 254 } 255 curr_cancelled = 0; 256 mtx_unlock_spin(&callout_lock); 257 if (c_mtx != NULL) { 258 mtx_lock(c_mtx); 259 /* 260 * The callout may have been cancelled 261 * while we switched locks. 262 */ 263 if (curr_cancelled) { 264 mtx_unlock(c_mtx); 265 mtx_lock_spin(&callout_lock); 266 goto done_locked; 267 } 268 /* The callout cannot be stopped now. */ 269 curr_cancelled = 1; 270 271 if (c_mtx == &Giant) { 272 gcalls++; 273 CTR1(KTR_CALLOUT, "callout %p", 274 c_func); 275 } else { 276 mtxcalls++; 277 CTR1(KTR_CALLOUT, 278 "callout mtx %p", 279 c_func); 280 } 281 } else { 282 mpcalls++; 283 CTR1(KTR_CALLOUT, "callout mpsafe %p", 284 c_func); 285 } 286 #ifdef DIAGNOSTIC 287 binuptime(&bt1); 288 #endif 289 THREAD_NO_SLEEPING(); 290 c_func(c_arg); 291 THREAD_SLEEPING_OK(); 292 #ifdef DIAGNOSTIC 293 binuptime(&bt2); 294 bintime_sub(&bt2, &bt1); 295 if (bt2.frac > maxdt) { 296 if (lastfunc != c_func || 297 bt2.frac > maxdt * 2) { 298 bintime2timespec(&bt2, &ts2); 299 printf( 300 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 301 c_func, c_arg, 302 (intmax_t)ts2.tv_sec, 303 ts2.tv_nsec); 304 } 305 maxdt = bt2.frac; 306 lastfunc = c_func; 307 } 308 #endif 309 if ((c_flags & CALLOUT_RETURNUNLOCKED) == 0) 310 mtx_unlock(c_mtx); 311 mtx_lock_spin(&callout_lock); 312 done_locked: 313 curr_callout = NULL; 314 if (wakeup_needed) { 315 /* 316 * There might be someone waiting 317 * for the callout to complete. 318 */ 319 wakeup_cookie = wakeup_ctr; 320 mtx_unlock_spin(&callout_lock); 321 mtx_lock(&callout_wait_lock); 322 cv_broadcast(&callout_wait); 323 wakeup_done_ctr = wakeup_cookie; 324 mtx_unlock(&callout_wait_lock); 325 mtx_lock_spin(&callout_lock); 326 wakeup_needed = 0; 327 } 328 steps = 0; 329 c = nextsoftcheck; 330 } 331 } 332 } 333 avg_depth += (depth * 1000 - avg_depth) >> 8; 334 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 335 avg_mtxcalls += (mtxcalls * 1000 - avg_mtxcalls) >> 8; 336 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 337 nextsoftcheck = NULL; 338 mtx_unlock_spin(&callout_lock); 339 } 340 341 /* 342 * timeout -- 343 * Execute a function after a specified length of time. 344 * 345 * untimeout -- 346 * Cancel previous timeout function call. 347 * 348 * callout_handle_init -- 349 * Initialize a handle so that using it with untimeout is benign. 350 * 351 * See AT&T BCI Driver Reference Manual for specification. This 352 * implementation differs from that one in that although an 353 * identification value is returned from timeout, the original 354 * arguments to timeout as well as the identifier are used to 355 * identify entries for untimeout. 356 */ 357 struct callout_handle 358 timeout(ftn, arg, to_ticks) 359 timeout_t *ftn; 360 void *arg; 361 int to_ticks; 362 { 363 struct callout *new; 364 struct callout_handle handle; 365 366 mtx_lock_spin(&callout_lock); 367 368 /* Fill in the next free callout structure. */ 369 new = SLIST_FIRST(&callfree); 370 if (new == NULL) 371 /* XXX Attempt to malloc first */ 372 panic("timeout table full"); 373 SLIST_REMOVE_HEAD(&callfree, c_links.sle); 374 375 callout_reset(new, to_ticks, ftn, arg); 376 377 handle.callout = new; 378 mtx_unlock_spin(&callout_lock); 379 return (handle); 380 } 381 382 void 383 untimeout(ftn, arg, handle) 384 timeout_t *ftn; 385 void *arg; 386 struct callout_handle handle; 387 { 388 389 /* 390 * Check for a handle that was initialized 391 * by callout_handle_init, but never used 392 * for a real timeout. 393 */ 394 if (handle.callout == NULL) 395 return; 396 397 mtx_lock_spin(&callout_lock); 398 if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) 399 callout_stop(handle.callout); 400 mtx_unlock_spin(&callout_lock); 401 } 402 403 void 404 callout_handle_init(struct callout_handle *handle) 405 { 406 handle->callout = NULL; 407 } 408 409 /* 410 * New interface; clients allocate their own callout structures. 411 * 412 * callout_reset() - establish or change a timeout 413 * callout_stop() - disestablish a timeout 414 * callout_init() - initialize a callout structure so that it can 415 * safely be passed to callout_reset() and callout_stop() 416 * 417 * <sys/callout.h> defines three convenience macros: 418 * 419 * callout_active() - returns truth if callout has not been stopped, 420 * drained, or deactivated since the last time the callout was 421 * reset. 422 * callout_pending() - returns truth if callout is still waiting for timeout 423 * callout_deactivate() - marks the callout as having been serviced 424 */ 425 int 426 callout_reset(c, to_ticks, ftn, arg) 427 struct callout *c; 428 int to_ticks; 429 void (*ftn)(void *); 430 void *arg; 431 { 432 int cancelled = 0; 433 434 #ifdef notyet /* Some callers of timeout() do not hold Giant. */ 435 if (c->c_mtx != NULL) 436 mtx_assert(c->c_mtx, MA_OWNED); 437 #endif 438 439 mtx_lock_spin(&callout_lock); 440 if (c == curr_callout) { 441 /* 442 * We're being asked to reschedule a callout which is 443 * currently in progress. If there is a mutex then we 444 * can cancel the callout if it has not really started. 445 */ 446 if (c->c_mtx != NULL && !curr_cancelled) 447 cancelled = curr_cancelled = 1; 448 if (wakeup_needed) { 449 /* 450 * Someone has called callout_drain to kill this 451 * callout. Don't reschedule. 452 */ 453 mtx_unlock_spin(&callout_lock); 454 return (cancelled); 455 } 456 } 457 if (c->c_flags & CALLOUT_PENDING) { 458 if (nextsoftcheck == c) { 459 nextsoftcheck = TAILQ_NEXT(c, c_links.tqe); 460 } 461 TAILQ_REMOVE(&callwheel[c->c_time & callwheelmask], c, 462 c_links.tqe); 463 464 cancelled = 1; 465 466 /* 467 * Part of the normal "stop a pending callout" process 468 * is to clear the CALLOUT_ACTIVE and CALLOUT_PENDING 469 * flags. We're not going to bother doing that here, 470 * because we're going to be setting those flags ten lines 471 * after this point, and we're holding callout_lock 472 * between now and then. 473 */ 474 } 475 476 /* 477 * We could unlock callout_lock here and lock it again before the 478 * TAILQ_INSERT_TAIL, but there's no point since doing this setup 479 * doesn't take much time. 480 */ 481 if (to_ticks <= 0) 482 to_ticks = 1; 483 484 c->c_arg = arg; 485 c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING); 486 c->c_func = ftn; 487 c->c_time = ticks + to_ticks; 488 TAILQ_INSERT_TAIL(&callwheel[c->c_time & callwheelmask], 489 c, c_links.tqe); 490 mtx_unlock_spin(&callout_lock); 491 492 return (cancelled); 493 } 494 495 int 496 _callout_stop_safe(c, safe) 497 struct callout *c; 498 int safe; 499 { 500 int use_mtx, wakeup_cookie; 501 502 if (!safe && c->c_mtx != NULL) { 503 #ifdef notyet /* Some callers do not hold Giant for Giant-locked callouts. */ 504 mtx_assert(c->c_mtx, MA_OWNED); 505 use_mtx = 1; 506 #else 507 use_mtx = mtx_owned(c->c_mtx); 508 #endif 509 } else { 510 use_mtx = 0; 511 } 512 513 mtx_lock_spin(&callout_lock); 514 /* 515 * Don't attempt to delete a callout that's not on the queue. 516 */ 517 if (!(c->c_flags & CALLOUT_PENDING)) { 518 c->c_flags &= ~CALLOUT_ACTIVE; 519 if (c != curr_callout) { 520 mtx_unlock_spin(&callout_lock); 521 return (0); 522 } 523 if (safe) { 524 /* We need to wait until the callout is finished. */ 525 wakeup_needed = 1; 526 wakeup_cookie = wakeup_ctr++; 527 mtx_unlock_spin(&callout_lock); 528 mtx_lock(&callout_wait_lock); 529 530 /* 531 * Check to make sure that softclock() didn't 532 * do the wakeup in between our dropping 533 * callout_lock and picking up callout_wait_lock 534 */ 535 if (wakeup_cookie - wakeup_done_ctr > 0) 536 cv_wait(&callout_wait, &callout_wait_lock); 537 538 mtx_unlock(&callout_wait_lock); 539 } else if (use_mtx && !curr_cancelled) { 540 /* We can stop the callout before it runs. */ 541 curr_cancelled = 1; 542 mtx_unlock_spin(&callout_lock); 543 return (1); 544 } else 545 mtx_unlock_spin(&callout_lock); 546 return (0); 547 } 548 c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING); 549 550 if (nextsoftcheck == c) { 551 nextsoftcheck = TAILQ_NEXT(c, c_links.tqe); 552 } 553 TAILQ_REMOVE(&callwheel[c->c_time & callwheelmask], c, c_links.tqe); 554 555 if (c->c_flags & CALLOUT_LOCAL_ALLOC) { 556 c->c_func = NULL; 557 SLIST_INSERT_HEAD(&callfree, c, c_links.sle); 558 } 559 mtx_unlock_spin(&callout_lock); 560 return (1); 561 } 562 563 void 564 callout_init(c, mpsafe) 565 struct callout *c; 566 int mpsafe; 567 { 568 bzero(c, sizeof *c); 569 if (mpsafe) { 570 c->c_mtx = NULL; 571 c->c_flags = CALLOUT_RETURNUNLOCKED; 572 } else { 573 c->c_mtx = &Giant; 574 c->c_flags = 0; 575 } 576 } 577 578 void 579 callout_init_mtx(c, mtx, flags) 580 struct callout *c; 581 struct mtx *mtx; 582 int flags; 583 { 584 bzero(c, sizeof *c); 585 c->c_mtx = mtx; 586 KASSERT((flags & ~CALLOUT_RETURNUNLOCKED) == 0, 587 ("callout_init_mtx: bad flags %d", flags)); 588 /* CALLOUT_RETURNUNLOCKED makes no sense without a mutex. */ 589 KASSERT(mtx != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 590 ("callout_init_mtx: CALLOUT_RETURNUNLOCKED with no mutex")); 591 c->c_flags = flags & CALLOUT_RETURNUNLOCKED; 592 } 593 594 #ifdef APM_FIXUP_CALLTODO 595 /* 596 * Adjust the kernel calltodo timeout list. This routine is used after 597 * an APM resume to recalculate the calltodo timer list values with the 598 * number of hz's we have been sleeping. The next hardclock() will detect 599 * that there are fired timers and run softclock() to execute them. 600 * 601 * Please note, I have not done an exhaustive analysis of what code this 602 * might break. I am motivated to have my select()'s and alarm()'s that 603 * have expired during suspend firing upon resume so that the applications 604 * which set the timer can do the maintanence the timer was for as close 605 * as possible to the originally intended time. Testing this code for a 606 * week showed that resuming from a suspend resulted in 22 to 25 timers 607 * firing, which seemed independant on whether the suspend was 2 hours or 608 * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu> 609 */ 610 void 611 adjust_timeout_calltodo(time_change) 612 struct timeval *time_change; 613 { 614 register struct callout *p; 615 unsigned long delta_ticks; 616 617 /* 618 * How many ticks were we asleep? 619 * (stolen from tvtohz()). 620 */ 621 622 /* Don't do anything */ 623 if (time_change->tv_sec < 0) 624 return; 625 else if (time_change->tv_sec <= LONG_MAX / 1000000) 626 delta_ticks = (time_change->tv_sec * 1000000 + 627 time_change->tv_usec + (tick - 1)) / tick + 1; 628 else if (time_change->tv_sec <= LONG_MAX / hz) 629 delta_ticks = time_change->tv_sec * hz + 630 (time_change->tv_usec + (tick - 1)) / tick + 1; 631 else 632 delta_ticks = LONG_MAX; 633 634 if (delta_ticks > INT_MAX) 635 delta_ticks = INT_MAX; 636 637 /* 638 * Now rip through the timer calltodo list looking for timers 639 * to expire. 640 */ 641 642 /* don't collide with softclock() */ 643 mtx_lock_spin(&callout_lock); 644 for (p = calltodo.c_next; p != NULL; p = p->c_next) { 645 p->c_time -= delta_ticks; 646 647 /* Break if the timer had more time on it than delta_ticks */ 648 if (p->c_time > 0) 649 break; 650 651 /* take back the ticks the timer didn't use (p->c_time <= 0) */ 652 delta_ticks = -p->c_time; 653 } 654 mtx_unlock_spin(&callout_lock); 655 656 return; 657 } 658 #endif /* APM_FIXUP_CALLTODO */
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