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("$FreeBSD$"); 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 in 82 * callout_drain() 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 is still 0 after 89 * c_mtx is successfully acquired. 90 * callout_wait - If a thread is waiting in callout_drain(), then 91 * callout_wait is nonzero. Set only when 92 * curr_callout is non-NULL. 93 */ 94 static struct callout *curr_callout; 95 static int curr_cancelled; 96 static int callout_wait; 97 98 /* 99 * kern_timeout_callwheel_alloc() - kernel low level callwheel initialization 100 * 101 * This code is called very early in the kernel initialization sequence, 102 * and may be called more then once. 103 */ 104 caddr_t 105 kern_timeout_callwheel_alloc(caddr_t v) 106 { 107 /* 108 * Calculate callout wheel size 109 */ 110 for (callwheelsize = 1, callwheelbits = 0; 111 callwheelsize < ncallout; 112 callwheelsize <<= 1, ++callwheelbits) 113 ; 114 callwheelmask = callwheelsize - 1; 115 116 callout = (struct callout *)v; 117 v = (caddr_t)(callout + ncallout); 118 callwheel = (struct callout_tailq *)v; 119 v = (caddr_t)(callwheel + callwheelsize); 120 return(v); 121 } 122 123 /* 124 * kern_timeout_callwheel_init() - initialize previously reserved callwheel 125 * space. 126 * 127 * This code is called just once, after the space reserved for the 128 * callout wheel has been finalized. 129 */ 130 void 131 kern_timeout_callwheel_init(void) 132 { 133 int i; 134 135 SLIST_INIT(&callfree); 136 for (i = 0; i < ncallout; i++) { 137 callout_init(&callout[i], 0); 138 callout[i].c_flags = CALLOUT_LOCAL_ALLOC; 139 SLIST_INSERT_HEAD(&callfree, &callout[i], c_links.sle); 140 } 141 for (i = 0; i < callwheelsize; i++) { 142 TAILQ_INIT(&callwheel[i]); 143 } 144 mtx_init(&callout_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); 145 } 146 147 /* 148 * The callout mechanism is based on the work of Adam M. Costello and 149 * George Varghese, published in a technical report entitled "Redesigning 150 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 151 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 152 * used in this implementation was published by G. Varghese and T. Lauck in 153 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 154 * the Efficient Implementation of a Timer Facility" in the Proceedings of 155 * the 11th ACM Annual Symposium on Operating Systems Principles, 156 * Austin, Texas Nov 1987. 157 */ 158 159 /* 160 * Software (low priority) clock interrupt. 161 * Run periodic events from timeout queue. 162 */ 163 void 164 softclock(void *dummy) 165 { 166 struct callout *c; 167 struct callout_tailq *bucket; 168 int curticks; 169 int steps; /* #steps since we last allowed interrupts */ 170 int depth; 171 int mpcalls; 172 int mtxcalls; 173 int gcalls; 174 #ifdef DIAGNOSTIC 175 struct bintime bt1, bt2; 176 struct timespec ts2; 177 static uint64_t maxdt = 36893488147419102LL; /* 2 msec */ 178 static timeout_t *lastfunc; 179 #endif 180 181 #ifndef MAX_SOFTCLOCK_STEPS 182 #define MAX_SOFTCLOCK_STEPS 100 /* Maximum allowed value of steps. */ 183 #endif /* MAX_SOFTCLOCK_STEPS */ 184 185 mpcalls = 0; 186 mtxcalls = 0; 187 gcalls = 0; 188 depth = 0; 189 steps = 0; 190 mtx_lock_spin(&callout_lock); 191 while (softticks != ticks) { 192 softticks++; 193 /* 194 * softticks may be modified by hard clock, so cache 195 * it while we work on a given bucket. 196 */ 197 curticks = softticks; 198 bucket = &callwheel[curticks & callwheelmask]; 199 c = TAILQ_FIRST(bucket); 200 while (c) { 201 depth++; 202 if (c->c_time != curticks) { 203 c = TAILQ_NEXT(c, c_links.tqe); 204 ++steps; 205 if (steps >= MAX_SOFTCLOCK_STEPS) { 206 nextsoftcheck = c; 207 /* Give interrupts a chance. */ 208 mtx_unlock_spin(&callout_lock); 209 ; /* nothing */ 210 mtx_lock_spin(&callout_lock); 211 c = nextsoftcheck; 212 steps = 0; 213 } 214 } else { 215 void (*c_func)(void *); 216 void *c_arg; 217 struct mtx *c_mtx; 218 int c_flags; 219 220 nextsoftcheck = TAILQ_NEXT(c, c_links.tqe); 221 TAILQ_REMOVE(bucket, c, c_links.tqe); 222 c_func = c->c_func; 223 c_arg = c->c_arg; 224 c_mtx = c->c_mtx; 225 c_flags = c->c_flags; 226 if (c->c_flags & CALLOUT_LOCAL_ALLOC) { 227 c->c_func = NULL; 228 c->c_flags = CALLOUT_LOCAL_ALLOC; 229 SLIST_INSERT_HEAD(&callfree, c, 230 c_links.sle); 231 curr_callout = NULL; 232 } else { 233 c->c_flags = 234 (c->c_flags & ~CALLOUT_PENDING); 235 curr_callout = c; 236 } 237 curr_cancelled = 0; 238 mtx_unlock_spin(&callout_lock); 239 if (c_mtx != NULL) { 240 if (c_flags & CALLOUT_NETGIANT) { 241 mtx_lock(&Giant); 242 gcalls++; 243 CTR3(KTR_CALLOUT, "netgiant" 244 " %p func %p arg %p", 245 c, c_func, c_arg); 246 } 247 mtx_lock(c_mtx); 248 /* 249 * The callout may have been cancelled 250 * while we switched locks. 251 */ 252 if (curr_cancelled) { 253 mtx_unlock(c_mtx); 254 goto skip; 255 } 256 /* The callout cannot be stopped now. */ 257 curr_cancelled = 1; 258 259 if (c_mtx == &Giant) { 260 gcalls++; 261 CTR3(KTR_CALLOUT, 262 "callout %p func %p arg %p", 263 c, c_func, c_arg); 264 } else { 265 mtxcalls++; 266 CTR3(KTR_CALLOUT, "callout mtx" 267 " %p func %p arg %p", 268 c, c_func, c_arg); 269 } 270 } else { 271 mpcalls++; 272 CTR3(KTR_CALLOUT, 273 "callout mpsafe %p func %p arg %p", 274 c, c_func, c_arg); 275 } 276 #ifdef DIAGNOSTIC 277 binuptime(&bt1); 278 #endif 279 THREAD_NO_SLEEPING(); 280 c_func(c_arg); 281 THREAD_SLEEPING_OK(); 282 #ifdef DIAGNOSTIC 283 binuptime(&bt2); 284 bintime_sub(&bt2, &bt1); 285 if (bt2.frac > maxdt) { 286 if (lastfunc != c_func || 287 bt2.frac > maxdt * 2) { 288 bintime2timespec(&bt2, &ts2); 289 printf( 290 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 291 c_func, c_arg, 292 (intmax_t)ts2.tv_sec, 293 ts2.tv_nsec); 294 } 295 maxdt = bt2.frac; 296 lastfunc = c_func; 297 } 298 #endif 299 if ((c_flags & CALLOUT_RETURNUNLOCKED) == 0) 300 mtx_unlock(c_mtx); 301 if (c_flags & CALLOUT_NETGIANT) 302 mtx_unlock(&Giant); 303 skip: 304 mtx_lock_spin(&callout_lock); 305 curr_callout = NULL; 306 if (callout_wait) { 307 /* 308 * There is someone waiting 309 * for the callout to complete. 310 */ 311 wakeup(&callout_wait); 312 callout_wait = 0; 313 } 314 steps = 0; 315 c = nextsoftcheck; 316 } 317 } 318 } 319 avg_depth += (depth * 1000 - avg_depth) >> 8; 320 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 321 avg_mtxcalls += (mtxcalls * 1000 - avg_mtxcalls) >> 8; 322 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 323 nextsoftcheck = NULL; 324 mtx_unlock_spin(&callout_lock); 325 } 326 327 /* 328 * timeout -- 329 * Execute a function after a specified length of time. 330 * 331 * untimeout -- 332 * Cancel previous timeout function call. 333 * 334 * callout_handle_init -- 335 * Initialize a handle so that using it with untimeout is benign. 336 * 337 * See AT&T BCI Driver Reference Manual for specification. This 338 * implementation differs from that one in that although an 339 * identification value is returned from timeout, the original 340 * arguments to timeout as well as the identifier are used to 341 * identify entries for untimeout. 342 */ 343 struct callout_handle 344 timeout(ftn, arg, to_ticks) 345 timeout_t *ftn; 346 void *arg; 347 int to_ticks; 348 { 349 struct callout *new; 350 struct callout_handle handle; 351 352 mtx_lock_spin(&callout_lock); 353 354 /* Fill in the next free callout structure. */ 355 new = SLIST_FIRST(&callfree); 356 if (new == NULL) 357 /* XXX Attempt to malloc first */ 358 panic("timeout table full"); 359 SLIST_REMOVE_HEAD(&callfree, c_links.sle); 360 361 callout_reset(new, to_ticks, ftn, arg); 362 363 handle.callout = new; 364 mtx_unlock_spin(&callout_lock); 365 return (handle); 366 } 367 368 void 369 untimeout(ftn, arg, handle) 370 timeout_t *ftn; 371 void *arg; 372 struct callout_handle handle; 373 { 374 375 /* 376 * Check for a handle that was initialized 377 * by callout_handle_init, but never used 378 * for a real timeout. 379 */ 380 if (handle.callout == NULL) 381 return; 382 383 mtx_lock_spin(&callout_lock); 384 if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) 385 callout_stop(handle.callout); 386 mtx_unlock_spin(&callout_lock); 387 } 388 389 void 390 callout_handle_init(struct callout_handle *handle) 391 { 392 handle->callout = NULL; 393 } 394 395 /* 396 * New interface; clients allocate their own callout structures. 397 * 398 * callout_reset() - establish or change a timeout 399 * callout_stop() - disestablish a timeout 400 * callout_init() - initialize a callout structure so that it can 401 * safely be passed to callout_reset() and callout_stop() 402 * 403 * <sys/callout.h> defines three convenience macros: 404 * 405 * callout_active() - returns truth if callout has not been stopped, 406 * drained, or deactivated since the last time the callout was 407 * reset. 408 * callout_pending() - returns truth if callout is still waiting for timeout 409 * callout_deactivate() - marks the callout as having been serviced 410 */ 411 int 412 callout_reset(c, to_ticks, ftn, arg) 413 struct callout *c; 414 int to_ticks; 415 void (*ftn)(void *); 416 void *arg; 417 { 418 int cancelled = 0; 419 420 #ifdef notyet /* Some callers of timeout() do not hold Giant. */ 421 if (c->c_mtx != NULL) 422 mtx_assert(c->c_mtx, MA_OWNED); 423 #endif 424 425 mtx_lock_spin(&callout_lock); 426 if (c == curr_callout) { 427 /* 428 * We're being asked to reschedule a callout which is 429 * currently in progress. If there is a mutex then we 430 * can cancel the callout if it has not really started. 431 */ 432 if (c->c_mtx != NULL && !curr_cancelled) 433 cancelled = curr_cancelled = 1; 434 if (callout_wait) { 435 /* 436 * Someone has called callout_drain to kill this 437 * callout. Don't reschedule. 438 */ 439 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 440 cancelled ? "cancelled" : "failed to cancel", 441 c, c->c_func, c->c_arg); 442 mtx_unlock_spin(&callout_lock); 443 return (cancelled); 444 } 445 } 446 if (c->c_flags & CALLOUT_PENDING) { 447 if (nextsoftcheck == c) { 448 nextsoftcheck = TAILQ_NEXT(c, c_links.tqe); 449 } 450 TAILQ_REMOVE(&callwheel[c->c_time & callwheelmask], c, 451 c_links.tqe); 452 453 cancelled = 1; 454 455 /* 456 * Part of the normal "stop a pending callout" process 457 * is to clear the CALLOUT_ACTIVE and CALLOUT_PENDING 458 * flags. We're not going to bother doing that here, 459 * because we're going to be setting those flags ten lines 460 * after this point, and we're holding callout_lock 461 * between now and then. 462 */ 463 } 464 465 /* 466 * We could unlock callout_lock here and lock it again before the 467 * TAILQ_INSERT_TAIL, but there's no point since doing this setup 468 * doesn't take much time. 469 */ 470 if (to_ticks <= 0) 471 to_ticks = 1; 472 473 c->c_arg = arg; 474 c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING); 475 c->c_func = ftn; 476 c->c_time = ticks + to_ticks; 477 TAILQ_INSERT_TAIL(&callwheel[c->c_time & callwheelmask], 478 c, c_links.tqe); 479 CTR5(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d", 480 cancelled ? "re" : "", c, c->c_func, c->c_arg, to_ticks); 481 mtx_unlock_spin(&callout_lock); 482 483 return (cancelled); 484 } 485 486 int 487 _callout_stop_safe(c, safe) 488 struct callout *c; 489 int safe; 490 { 491 int use_mtx; 492 493 if (!safe && c->c_mtx != NULL) { 494 #ifdef notyet /* Some callers do not hold Giant for Giant-locked callouts. */ 495 mtx_assert(c->c_mtx, MA_OWNED); 496 use_mtx = 1; 497 #else 498 use_mtx = mtx_owned(c->c_mtx); 499 #endif 500 } else { 501 use_mtx = 0; 502 } 503 504 mtx_lock_spin(&callout_lock); 505 /* 506 * If the callout isn't pending, it's not on the queue, so 507 * don't attempt to remove it from the queue. We can try to 508 * stop it by other means however. 509 */ 510 if (!(c->c_flags & CALLOUT_PENDING)) { 511 c->c_flags &= ~CALLOUT_ACTIVE; 512 513 /* 514 * If it wasn't on the queue and it isn't the current 515 * callout, then we can't stop it, so just bail. 516 */ 517 if (c != curr_callout) { 518 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 519 c, c->c_func, c->c_arg); 520 mtx_unlock_spin(&callout_lock); 521 return (0); 522 } 523 524 if (safe) { 525 /* 526 * The current callout is running (or just 527 * about to run) and blocking is allowed, so 528 * just wait for the current invocation to 529 * finish. 530 */ 531 while (c == curr_callout) { 532 callout_wait = 1; 533 msleep_spin(&callout_wait, &callout_lock, 534 "codrain", 0); 535 } 536 } else if (use_mtx && !curr_cancelled) { 537 /* 538 * The current callout is waiting for it's 539 * mutex which we hold. Cancel the callout 540 * and return. After our caller drops the 541 * mutex, the callout will be skipped in 542 * softclock(). 543 */ 544 curr_cancelled = 1; 545 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 546 c, c->c_func, c->c_arg); 547 mtx_unlock_spin(&callout_lock); 548 return (1); 549 } 550 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 551 c, c->c_func, c->c_arg); 552 mtx_unlock_spin(&callout_lock); 553 return (0); 554 } 555 c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING); 556 557 if (nextsoftcheck == c) { 558 nextsoftcheck = TAILQ_NEXT(c, c_links.tqe); 559 } 560 TAILQ_REMOVE(&callwheel[c->c_time & callwheelmask], c, c_links.tqe); 561 562 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 563 c, c->c_func, c->c_arg); 564 565 if (c->c_flags & CALLOUT_LOCAL_ALLOC) { 566 c->c_func = NULL; 567 SLIST_INSERT_HEAD(&callfree, c, c_links.sle); 568 } 569 mtx_unlock_spin(&callout_lock); 570 return (1); 571 } 572 573 void 574 callout_init(c, mpsafe) 575 struct callout *c; 576 int mpsafe; 577 { 578 bzero(c, sizeof *c); 579 if (mpsafe) { 580 c->c_mtx = NULL; 581 c->c_flags = CALLOUT_RETURNUNLOCKED; 582 } else { 583 c->c_mtx = &Giant; 584 c->c_flags = 0; 585 } 586 } 587 588 void 589 callout_init_mtx(c, mtx, flags) 590 struct callout *c; 591 struct mtx *mtx; 592 int flags; 593 { 594 bzero(c, sizeof *c); 595 c->c_mtx = mtx; 596 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED|CALLOUT_NETGIANT)) == 0, 597 ("callout_init_mtx: bad flags %d", flags)); 598 /* CALLOUT_RETURNUNLOCKED makes no sense without a mutex. */ 599 KASSERT(mtx != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 600 ("callout_init_mtx: CALLOUT_RETURNUNLOCKED with no mutex")); 601 c->c_flags = flags & (CALLOUT_RETURNUNLOCKED|CALLOUT_NETGIANT); 602 } 603 604 #ifdef APM_FIXUP_CALLTODO 605 /* 606 * Adjust the kernel calltodo timeout list. This routine is used after 607 * an APM resume to recalculate the calltodo timer list values with the 608 * number of hz's we have been sleeping. The next hardclock() will detect 609 * that there are fired timers and run softclock() to execute them. 610 * 611 * Please note, I have not done an exhaustive analysis of what code this 612 * might break. I am motivated to have my select()'s and alarm()'s that 613 * have expired during suspend firing upon resume so that the applications 614 * which set the timer can do the maintanence the timer was for as close 615 * as possible to the originally intended time. Testing this code for a 616 * week showed that resuming from a suspend resulted in 22 to 25 timers 617 * firing, which seemed independant on whether the suspend was 2 hours or 618 * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu> 619 */ 620 void 621 adjust_timeout_calltodo(time_change) 622 struct timeval *time_change; 623 { 624 register struct callout *p; 625 unsigned long delta_ticks; 626 627 /* 628 * How many ticks were we asleep? 629 * (stolen from tvtohz()). 630 */ 631 632 /* Don't do anything */ 633 if (time_change->tv_sec < 0) 634 return; 635 else if (time_change->tv_sec <= LONG_MAX / 1000000) 636 delta_ticks = (time_change->tv_sec * 1000000 + 637 time_change->tv_usec + (tick - 1)) / tick + 1; 638 else if (time_change->tv_sec <= LONG_MAX / hz) 639 delta_ticks = time_change->tv_sec * hz + 640 (time_change->tv_usec + (tick - 1)) / tick + 1; 641 else 642 delta_ticks = LONG_MAX; 643 644 if (delta_ticks > INT_MAX) 645 delta_ticks = INT_MAX; 646 647 /* 648 * Now rip through the timer calltodo list looking for timers 649 * to expire. 650 */ 651 652 /* don't collide with softclock() */ 653 mtx_lock_spin(&callout_lock); 654 for (p = calltodo.c_next; p != NULL; p = p->c_next) { 655 p->c_time -= delta_ticks; 656 657 /* Break if the timer had more time on it than delta_ticks */ 658 if (p->c_time > 0) 659 break; 660 661 /* take back the ticks the timer didn't use (p->c_time <= 0) */ 662 delta_ticks = -p->c_time; 663 } 664 mtx_unlock_spin(&callout_lock); 665 666 return; 667 } 668 #endif /* APM_FIXUP_CALLTODO */ 669