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/sysctl.h> 49 50 static int avg_depth; 51 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, 52 "Average number of items examined per softclock call. Units = 1/1000"); 53 static int avg_gcalls; 54 SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, 55 "Average number of Giant callouts made per softclock call. Units = 1/1000"); 56 static int avg_mtxcalls; 57 SYSCTL_INT(_debug, OID_AUTO, to_avg_mtxcalls, CTLFLAG_RD, &avg_mtxcalls, 0, 58 "Average number of mtx callouts made per softclock call. Units = 1/1000"); 59 static int avg_mpcalls; 60 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, 61 "Average number of MP callouts made per softclock call. Units = 1/1000"); 62 /* 63 * TODO: 64 * allocate more timeout table slots when table overflows. 65 */ 66 67 /* Exported to machdep.c and/or kern_clock.c. */ 68 struct callout *callout; 69 struct callout_list callfree; 70 int callwheelsize, callwheelbits, callwheelmask; 71 struct callout_tailq *callwheel; 72 int softticks; /* Like ticks, but for softclock(). */ 73 struct mtx callout_lock; 74 #ifdef DIAGNOSTIC 75 struct mtx dont_sleep_in_callout; 76 #endif 77 78 static struct callout *nextsoftcheck; /* Next callout to be checked. */ 79 80 /** 81 * Locked by callout_lock: 82 * curr_callout - If a callout is in progress, it is curr_callout. 83 * If curr_callout is non-NULL, threads waiting on 84 * callout_wait will be woken up as soon as the 85 * relevant callout completes. 86 * curr_cancelled - Changing to 1 with both callout_lock and c_mtx held 87 * guarantees that the current callout will not run. 88 * The softclock() function sets this to 0 before it 89 * drops callout_lock to acquire c_mtx, and it calls 90 * the handler only if curr_cancelled still 0 when 91 * c_mtx is successfully acquired. 92 * wakeup_ctr - Incremented every time a thread wants to wait 93 * for a callout to complete. Modified only when 94 * curr_callout is non-NULL. 95 * wakeup_needed - If a thread is waiting on callout_wait, then 96 * wakeup_needed is nonzero. Increased only when 97 * cutt_callout is non-NULL. 98 */ 99 static struct callout *curr_callout; 100 static int curr_cancelled; 101 static int wakeup_ctr; 102 static int wakeup_needed; 103 104 /** 105 * Locked by callout_wait_lock: 106 * callout_wait - If wakeup_needed is set, callout_wait will be 107 * triggered after the current callout finishes. 108 * wakeup_done_ctr - Set to the current value of wakeup_ctr after 109 * callout_wait is triggered. 110 */ 111 static struct mtx callout_wait_lock; 112 static struct cv callout_wait; 113 static int wakeup_done_ctr; 114 115 /* 116 * kern_timeout_callwheel_alloc() - kernel low level callwheel initialization 117 * 118 * This code is called very early in the kernel initialization sequence, 119 * and may be called more then once. 120 */ 121 caddr_t 122 kern_timeout_callwheel_alloc(caddr_t v) 123 { 124 /* 125 * Calculate callout wheel size 126 */ 127 for (callwheelsize = 1, callwheelbits = 0; 128 callwheelsize < ncallout; 129 callwheelsize <<= 1, ++callwheelbits) 130 ; 131 callwheelmask = callwheelsize - 1; 132 133 callout = (struct callout *)v; 134 v = (caddr_t)(callout + ncallout); 135 callwheel = (struct callout_tailq *)v; 136 v = (caddr_t)(callwheel + callwheelsize); 137 return(v); 138 } 139 140 /* 141 * kern_timeout_callwheel_init() - initialize previously reserved callwheel 142 * space. 143 * 144 * This code is called just once, after the space reserved for the 145 * callout wheel has been finalized. 146 */ 147 void 148 kern_timeout_callwheel_init(void) 149 { 150 int i; 151 152 SLIST_INIT(&callfree); 153 for (i = 0; i < ncallout; i++) { 154 callout_init(&callout[i], 0); 155 callout[i].c_flags = CALLOUT_LOCAL_ALLOC; 156 SLIST_INSERT_HEAD(&callfree, &callout[i], c_links.sle); 157 } 158 for (i = 0; i < callwheelsize; i++) { 159 TAILQ_INIT(&callwheel[i]); 160 } 161 mtx_init(&callout_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); 162 #ifdef DIAGNOSTIC 163 mtx_init(&dont_sleep_in_callout, "dont_sleep_in_callout", NULL, MTX_DEF); 164 #endif 165 mtx_init(&callout_wait_lock, "callout_wait_lock", NULL, MTX_DEF); 166 cv_init(&callout_wait, "callout_wait"); 167 } 168 169 /* 170 * The callout mechanism is based on the work of Adam M. Costello and 171 * George Varghese, published in a technical report entitled "Redesigning 172 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 173 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 174 * used in this implementation was published by G. Varghese and T. Lauck in 175 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 176 * the Efficient Implementation of a Timer Facility" in the Proceedings of 177 * the 11th ACM Annual Symposium on Operating Systems Principles, 178 * Austin, Texas Nov 1987. 179 */ 180 181 /* 182 * Software (low priority) clock interrupt. 183 * Run periodic events from timeout queue. 184 */ 185 void 186 softclock(void *dummy) 187 { 188 struct callout *c; 189 struct callout_tailq *bucket; 190 int curticks; 191 int steps; /* #steps since we last allowed interrupts */ 192 int depth; 193 int mpcalls; 194 int mtxcalls; 195 int gcalls; 196 int wakeup_cookie; 197 #ifdef DIAGNOSTIC 198 struct bintime bt1, bt2; 199 struct timespec ts2; 200 static uint64_t maxdt = 36893488147419102LL; /* 2 msec */ 201 static timeout_t *lastfunc; 202 #endif 203 204 #ifndef MAX_SOFTCLOCK_STEPS 205 #define MAX_SOFTCLOCK_STEPS 100 /* Maximum allowed value of steps. */ 206 #endif /* MAX_SOFTCLOCK_STEPS */ 207 208 mpcalls = 0; 209 mtxcalls = 0; 210 gcalls = 0; 211 depth = 0; 212 steps = 0; 213 mtx_lock_spin(&callout_lock); 214 while (softticks != ticks) { 215 softticks++; 216 /* 217 * softticks may be modified by hard clock, so cache 218 * it while we work on a given bucket. 219 */ 220 curticks = softticks; 221 bucket = &callwheel[curticks & callwheelmask]; 222 c = TAILQ_FIRST(bucket); 223 while (c) { 224 depth++; 225 if (c->c_time != curticks) { 226 c = TAILQ_NEXT(c, c_links.tqe); 227 ++steps; 228 if (steps >= MAX_SOFTCLOCK_STEPS) { 229 nextsoftcheck = c; 230 /* Give interrupts a chance. */ 231 mtx_unlock_spin(&callout_lock); 232 ; /* nothing */ 233 mtx_lock_spin(&callout_lock); 234 c = nextsoftcheck; 235 steps = 0; 236 } 237 } else { 238 void (*c_func)(void *); 239 void *c_arg; 240 struct mtx *c_mtx; 241 int c_flags; 242 243 nextsoftcheck = TAILQ_NEXT(c, c_links.tqe); 244 TAILQ_REMOVE(bucket, c, c_links.tqe); 245 c_func = c->c_func; 246 c_arg = c->c_arg; 247 c_mtx = c->c_mtx; 248 c_flags = c->c_flags; 249 if (c->c_flags & CALLOUT_LOCAL_ALLOC) { 250 c->c_func = NULL; 251 c->c_flags = CALLOUT_LOCAL_ALLOC; 252 SLIST_INSERT_HEAD(&callfree, c, 253 c_links.sle); 254 curr_callout = NULL; 255 } else { 256 c->c_flags = 257 (c->c_flags & ~CALLOUT_PENDING); 258 curr_callout = c; 259 } 260 curr_cancelled = 0; 261 mtx_unlock_spin(&callout_lock); 262 if (c_mtx != NULL) { 263 mtx_lock(c_mtx); 264 /* 265 * The callout may have been cancelled 266 * while we switched locks. 267 */ 268 if (curr_cancelled) { 269 mtx_unlock(c_mtx); 270 mtx_lock_spin(&callout_lock); 271 goto done_locked; 272 } 273 /* The callout cannot be stopped now. */ 274 curr_cancelled = 1; 275 276 if (c_mtx == &Giant) { 277 gcalls++; 278 CTR1(KTR_CALLOUT, "callout %p", 279 c_func); 280 } else { 281 mtxcalls++; 282 CTR1(KTR_CALLOUT, 283 "callout mtx %p", 284 c_func); 285 } 286 } else { 287 mpcalls++; 288 CTR1(KTR_CALLOUT, "callout mpsafe %p", 289 c_func); 290 } 291 #ifdef DIAGNOSTIC 292 binuptime(&bt1); 293 mtx_lock(&dont_sleep_in_callout); 294 #endif 295 c_func(c_arg); 296 #ifdef DIAGNOSTIC 297 mtx_unlock(&dont_sleep_in_callout); 298 binuptime(&bt2); 299 bintime_sub(&bt2, &bt1); 300 if (bt2.frac > maxdt) { 301 if (lastfunc != c_func || 302 bt2.frac > maxdt * 2) { 303 bintime2timespec(&bt2, &ts2); 304 printf( 305 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 306 c_func, c_arg, 307 (intmax_t)ts2.tv_sec, 308 ts2.tv_nsec); 309 } 310 maxdt = bt2.frac; 311 lastfunc = c_func; 312 } 313 #endif 314 if ((c_flags & CALLOUT_RETURNUNLOCKED) == 0) 315 mtx_unlock(c_mtx); 316 mtx_lock_spin(&callout_lock); 317 done_locked: 318 curr_callout = NULL; 319 if (wakeup_needed) { 320 /* 321 * There might be someone waiting 322 * for the callout to complete. 323 */ 324 wakeup_cookie = wakeup_ctr; 325 mtx_unlock_spin(&callout_lock); 326 mtx_lock(&callout_wait_lock); 327 cv_broadcast(&callout_wait); 328 wakeup_done_ctr = wakeup_cookie; 329 mtx_unlock(&callout_wait_lock); 330 mtx_lock_spin(&callout_lock); 331 wakeup_needed = 0; 332 } 333 steps = 0; 334 c = nextsoftcheck; 335 } 336 } 337 } 338 avg_depth += (depth * 1000 - avg_depth) >> 8; 339 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 340 avg_mtxcalls += (mtxcalls * 1000 - avg_mtxcalls) >> 8; 341 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 342 nextsoftcheck = NULL; 343 mtx_unlock_spin(&callout_lock); 344 } 345 346 /* 347 * timeout -- 348 * Execute a function after a specified length of time. 349 * 350 * untimeout -- 351 * Cancel previous timeout function call. 352 * 353 * callout_handle_init -- 354 * Initialize a handle so that using it with untimeout is benign. 355 * 356 * See AT&T BCI Driver Reference Manual for specification. This 357 * implementation differs from that one in that although an 358 * identification value is returned from timeout, the original 359 * arguments to timeout as well as the identifier are used to 360 * identify entries for untimeout. 361 */ 362 struct callout_handle 363 timeout(ftn, arg, to_ticks) 364 timeout_t *ftn; 365 void *arg; 366 int to_ticks; 367 { 368 struct callout *new; 369 struct callout_handle handle; 370 371 mtx_lock_spin(&callout_lock); 372 373 /* Fill in the next free callout structure. */ 374 new = SLIST_FIRST(&callfree); 375 if (new == NULL) 376 /* XXX Attempt to malloc first */ 377 panic("timeout table full"); 378 SLIST_REMOVE_HEAD(&callfree, c_links.sle); 379 380 callout_reset(new, to_ticks, ftn, arg); 381 382 handle.callout = new; 383 mtx_unlock_spin(&callout_lock); 384 return (handle); 385 } 386 387 void 388 untimeout(ftn, arg, handle) 389 timeout_t *ftn; 390 void *arg; 391 struct callout_handle handle; 392 { 393 394 /* 395 * Check for a handle that was initialized 396 * by callout_handle_init, but never used 397 * for a real timeout. 398 */ 399 if (handle.callout == NULL) 400 return; 401 402 mtx_lock_spin(&callout_lock); 403 if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) 404 callout_stop(handle.callout); 405 mtx_unlock_spin(&callout_lock); 406 } 407 408 void 409 callout_handle_init(struct callout_handle *handle) 410 { 411 handle->callout = NULL; 412 } 413 414 /* 415 * New interface; clients allocate their own callout structures. 416 * 417 * callout_reset() - establish or change a timeout 418 * callout_stop() - disestablish a timeout 419 * callout_init() - initialize a callout structure so that it can 420 * safely be passed to callout_reset() and callout_stop() 421 * 422 * <sys/callout.h> defines three convenience macros: 423 * 424 * callout_active() - returns truth if callout has not been stopped, 425 * drained, or deactivated since the last time the callout was 426 * reset. 427 * callout_pending() - returns truth if callout is still waiting for timeout 428 * callout_deactivate() - marks the callout as having been serviced 429 */ 430 void 431 callout_reset(c, to_ticks, ftn, arg) 432 struct callout *c; 433 int to_ticks; 434 void (*ftn)(void *); 435 void *arg; 436 { 437 438 #ifdef notyet /* Some callers of timeout() do not hold Giant. */ 439 if (c->c_mtx != NULL) 440 mtx_assert(c->c_mtx, MA_OWNED); 441 #endif 442 443 mtx_lock_spin(&callout_lock); 444 if (c == curr_callout) { 445 /* 446 * We're being asked to reschedule a callout which is 447 * currently in progress. If there is a mutex then we 448 * can cancel the callout if it has not really started. 449 */ 450 if (c->c_mtx != NULL && !curr_cancelled) 451 curr_cancelled = 1; 452 if (wakeup_needed) { 453 /* 454 * Someone has called callout_drain to kill this 455 * callout. Don't reschedule. 456 */ 457 mtx_unlock_spin(&callout_lock); 458 return; 459 } 460 } 461 if (c->c_flags & CALLOUT_PENDING) { 462 if (nextsoftcheck == c) { 463 nextsoftcheck = TAILQ_NEXT(c, c_links.tqe); 464 } 465 TAILQ_REMOVE(&callwheel[c->c_time & callwheelmask], c, 466 c_links.tqe); 467 468 /* 469 * Part of the normal "stop a pending callout" process 470 * is to clear the CALLOUT_ACTIVE and CALLOUT_PENDING 471 * flags. We're not going to bother doing that here, 472 * because we're going to be setting those flags ten lines 473 * after this point, and we're holding callout_lock 474 * between now and then. 475 */ 476 } 477 478 /* 479 * We could unlock callout_lock here and lock it again before the 480 * TAILQ_INSERT_TAIL, but there's no point since doing this setup 481 * doesn't take much time. 482 */ 483 if (to_ticks <= 0) 484 to_ticks = 1; 485 486 c->c_arg = arg; 487 c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING); 488 c->c_func = ftn; 489 c->c_time = ticks + to_ticks; 490 TAILQ_INSERT_TAIL(&callwheel[c->c_time & callwheelmask], 491 c, c_links.tqe); 492 mtx_unlock_spin(&callout_lock); 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 */ 659