1 /* $NetBSD: kern_timeout.c,v 1.41 2008/07/02 14:47:34 matt Exp $ */ 2 3 /*- 4 * Copyright (c) 2003, 2006, 2007, 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe, and by Andrew Doran. 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Copyright (c) 2001 Thomas Nordin <nordin@openbsd.org> 34 * Copyright (c) 2000-2001 Artur Grabowski <art@openbsd.org> 35 * All rights reserved. 36 * 37 * Redistribution and use in source and binary forms, with or without 38 * modification, are permitted provided that the following conditions 39 * are met: 40 * 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 3. The name of the author may not be used to endorse or promote products 47 * derived from this software without specific prior written permission. 48 * 49 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 50 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 51 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 52 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 53 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 54 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 55 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 56 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 57 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 58 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 59 */ 60 61 #include <sys/cdefs.h> 62 __KERNEL_RCSID(0, "$NetBSD: kern_timeout.c,v 1.41 2008/07/02 14:47:34 matt Exp $"); 63 64 /* 65 * Timeouts are kept in a hierarchical timing wheel. The c_time is the 66 * value of c_cpu->cc_ticks when the timeout should be called. There are 67 * four levels with 256 buckets each. See 'Scheme 7' in "Hashed and 68 * Hierarchical Timing Wheels: Efficient Data Structures for Implementing 69 * a Timer Facility" by George Varghese and Tony Lauck. 70 * 71 * Some of the "math" in here is a bit tricky. We have to beware of 72 * wrapping ints. 73 * 74 * We use the fact that any element added to the queue must be added with 75 * a positive time. That means that any element `to' on the queue cannot 76 * be scheduled to timeout further in time than INT_MAX, but c->c_time can 77 * be positive or negative so comparing it with anything is dangerous. 78 * The only way we can use the c->c_time value in any predictable way is 79 * when we calculate how far in the future `to' will timeout - "c->c_time 80 * - c->c_cpu->cc_ticks". The result will always be positive for future 81 * timeouts and 0 or negative for due timeouts. 82 */ 83 84 #define _CALLOUT_PRIVATE 85 86 #include <sys/param.h> 87 #include <sys/systm.h> 88 #include <sys/kernel.h> 89 #include <sys/callout.h> 90 #include <sys/mutex.h> 91 #include <sys/proc.h> 92 #include <sys/sleepq.h> 93 #include <sys/syncobj.h> 94 #include <sys/evcnt.h> 95 #include <sys/intr.h> 96 #include <sys/cpu.h> 97 #include <sys/kmem.h> 98 99 #ifdef DDB 100 #include <machine/db_machdep.h> 101 #include <ddb/db_interface.h> 102 #include <ddb/db_access.h> 103 #include <ddb/db_sym.h> 104 #include <ddb/db_output.h> 105 #endif 106 107 #define BUCKETS 1024 108 #define WHEELSIZE 256 109 #define WHEELMASK 255 110 #define WHEELBITS 8 111 112 #define MASKWHEEL(wheel, time) (((time) >> ((wheel)*WHEELBITS)) & WHEELMASK) 113 114 #define BUCKET(cc, rel, abs) \ 115 (((rel) <= (1 << (2*WHEELBITS))) \ 116 ? ((rel) <= (1 << WHEELBITS)) \ 117 ? &(cc)->cc_wheel[MASKWHEEL(0, (abs))] \ 118 : &(cc)->cc_wheel[MASKWHEEL(1, (abs)) + WHEELSIZE] \ 119 : ((rel) <= (1 << (3*WHEELBITS))) \ 120 ? &(cc)->cc_wheel[MASKWHEEL(2, (abs)) + 2*WHEELSIZE] \ 121 : &(cc)->cc_wheel[MASKWHEEL(3, (abs)) + 3*WHEELSIZE]) 122 123 #define MOVEBUCKET(cc, wheel, time) \ 124 CIRCQ_APPEND(&(cc)->cc_todo, \ 125 &(cc)->cc_wheel[MASKWHEEL((wheel), (time)) + (wheel)*WHEELSIZE]) 126 127 /* 128 * Circular queue definitions. 129 */ 130 131 #define CIRCQ_INIT(list) \ 132 do { \ 133 (list)->cq_next_l = (list); \ 134 (list)->cq_prev_l = (list); \ 135 } while (/*CONSTCOND*/0) 136 137 #define CIRCQ_INSERT(elem, list) \ 138 do { \ 139 (elem)->cq_prev_e = (list)->cq_prev_e; \ 140 (elem)->cq_next_l = (list); \ 141 (list)->cq_prev_l->cq_next_l = (elem); \ 142 (list)->cq_prev_l = (elem); \ 143 } while (/*CONSTCOND*/0) 144 145 #define CIRCQ_APPEND(fst, snd) \ 146 do { \ 147 if (!CIRCQ_EMPTY(snd)) { \ 148 (fst)->cq_prev_l->cq_next_l = (snd)->cq_next_l; \ 149 (snd)->cq_next_l->cq_prev_l = (fst)->cq_prev_l; \ 150 (snd)->cq_prev_l->cq_next_l = (fst); \ 151 (fst)->cq_prev_l = (snd)->cq_prev_l; \ 152 CIRCQ_INIT(snd); \ 153 } \ 154 } while (/*CONSTCOND*/0) 155 156 #define CIRCQ_REMOVE(elem) \ 157 do { \ 158 (elem)->cq_next_l->cq_prev_e = (elem)->cq_prev_e; \ 159 (elem)->cq_prev_l->cq_next_e = (elem)->cq_next_e; \ 160 } while (/*CONSTCOND*/0) 161 162 #define CIRCQ_FIRST(list) ((list)->cq_next_e) 163 #define CIRCQ_NEXT(elem) ((elem)->cq_next_e) 164 #define CIRCQ_LAST(elem,list) ((elem)->cq_next_l == (list)) 165 #define CIRCQ_EMPTY(list) ((list)->cq_next_l == (list)) 166 167 static void callout_softclock(void *); 168 169 struct callout_cpu { 170 kmutex_t cc_lock; 171 sleepq_t cc_sleepq; 172 u_int cc_nwait; 173 u_int cc_ticks; 174 lwp_t *cc_lwp; 175 callout_impl_t *cc_active; 176 callout_impl_t *cc_cancel; 177 struct evcnt cc_ev_late; 178 struct evcnt cc_ev_block; 179 struct callout_circq cc_todo; /* Worklist */ 180 struct callout_circq cc_wheel[BUCKETS]; /* Queues of timeouts */ 181 char cc_name1[12]; 182 char cc_name2[12]; 183 }; 184 185 static struct callout_cpu callout_cpu0; 186 static void *callout_sih; 187 188 static inline kmutex_t * 189 callout_lock(callout_impl_t *c) 190 { 191 kmutex_t *lock; 192 193 for (;;) { 194 lock = &c->c_cpu->cc_lock; 195 mutex_spin_enter(lock); 196 if (__predict_true(lock == &c->c_cpu->cc_lock)) 197 return lock; 198 mutex_spin_exit(lock); 199 } 200 } 201 202 /* 203 * callout_startup: 204 * 205 * Initialize the callout facility, called at system startup time. 206 * Do just enough to allow callouts to be safely registered. 207 */ 208 void 209 callout_startup(void) 210 { 211 struct callout_cpu *cc; 212 int b; 213 214 KASSERT(curcpu()->ci_data.cpu_callout == NULL); 215 216 cc = &callout_cpu0; 217 mutex_init(&cc->cc_lock, MUTEX_DEFAULT, IPL_SCHED); 218 CIRCQ_INIT(&cc->cc_todo); 219 for (b = 0; b < BUCKETS; b++) 220 CIRCQ_INIT(&cc->cc_wheel[b]); 221 curcpu()->ci_data.cpu_callout = cc; 222 } 223 224 /* 225 * callout_init_cpu: 226 * 227 * Per-CPU initialization. 228 */ 229 void 230 callout_init_cpu(struct cpu_info *ci) 231 { 232 struct callout_cpu *cc; 233 int b; 234 235 CTASSERT(sizeof(callout_impl_t) <= sizeof(callout_t)); 236 237 if ((cc = ci->ci_data.cpu_callout) == NULL) { 238 cc = kmem_zalloc(sizeof(*cc), KM_SLEEP); 239 if (cc == NULL) 240 panic("callout_init_cpu (1)"); 241 mutex_init(&cc->cc_lock, MUTEX_DEFAULT, IPL_SCHED); 242 CIRCQ_INIT(&cc->cc_todo); 243 for (b = 0; b < BUCKETS; b++) 244 CIRCQ_INIT(&cc->cc_wheel[b]); 245 } else { 246 /* Boot CPU, one time only. */ 247 callout_sih = softint_establish(SOFTINT_CLOCK | SOFTINT_MPSAFE, 248 callout_softclock, NULL); 249 if (callout_sih == NULL) 250 panic("callout_init_cpu (2)"); 251 } 252 253 sleepq_init(&cc->cc_sleepq); 254 255 snprintf(cc->cc_name1, sizeof(cc->cc_name1), "late/%u", 256 cpu_index(ci)); 257 evcnt_attach_dynamic(&cc->cc_ev_late, EVCNT_TYPE_MISC, 258 NULL, "callout", cc->cc_name1); 259 260 snprintf(cc->cc_name2, sizeof(cc->cc_name2), "wait/%u", 261 cpu_index(ci)); 262 evcnt_attach_dynamic(&cc->cc_ev_block, EVCNT_TYPE_MISC, 263 NULL, "callout", cc->cc_name2); 264 265 ci->ci_data.cpu_callout = cc; 266 } 267 268 /* 269 * callout_init: 270 * 271 * Initialize a callout structure. This must be quick, so we fill 272 * only the minimum number of fields. 273 */ 274 void 275 callout_init(callout_t *cs, u_int flags) 276 { 277 callout_impl_t *c = (callout_impl_t *)cs; 278 struct callout_cpu *cc; 279 280 KASSERT((flags & ~CALLOUT_FLAGMASK) == 0); 281 282 cc = curcpu()->ci_data.cpu_callout; 283 c->c_func = NULL; 284 c->c_magic = CALLOUT_MAGIC; 285 if (__predict_true((flags & CALLOUT_MPSAFE) != 0 && cc != NULL)) { 286 c->c_flags = flags; 287 c->c_cpu = cc; 288 return; 289 } 290 c->c_flags = flags | CALLOUT_BOUND; 291 c->c_cpu = &callout_cpu0; 292 } 293 294 /* 295 * callout_destroy: 296 * 297 * Destroy a callout structure. The callout must be stopped. 298 */ 299 void 300 callout_destroy(callout_t *cs) 301 { 302 callout_impl_t *c = (callout_impl_t *)cs; 303 304 /* 305 * It's not necessary to lock in order to see the correct value 306 * of c->c_flags. If the callout could potentially have been 307 * running, the current thread should have stopped it. 308 */ 309 KASSERT((c->c_flags & CALLOUT_PENDING) == 0); 310 KASSERT(c->c_cpu->cc_lwp == curlwp || c->c_cpu->cc_active != c); 311 KASSERT(c->c_magic == CALLOUT_MAGIC); 312 c->c_magic = 0; 313 } 314 315 /* 316 * callout_schedule_locked: 317 * 318 * Schedule a callout to run. The function and argument must 319 * already be set in the callout structure. Must be called with 320 * callout_lock. 321 */ 322 static void 323 callout_schedule_locked(callout_impl_t *c, kmutex_t *lock, int to_ticks) 324 { 325 struct callout_cpu *cc, *occ; 326 int old_time; 327 328 KASSERT(to_ticks >= 0); 329 KASSERT(c->c_func != NULL); 330 331 /* Initialize the time here, it won't change. */ 332 occ = c->c_cpu; 333 c->c_flags &= ~CALLOUT_FIRED; 334 335 /* 336 * If this timeout is already scheduled and now is moved 337 * earlier, reschedule it now. Otherwise leave it in place 338 * and let it be rescheduled later. 339 */ 340 if ((c->c_flags & CALLOUT_PENDING) != 0) { 341 /* Leave on existing CPU. */ 342 old_time = c->c_time; 343 c->c_time = to_ticks + occ->cc_ticks; 344 if (c->c_time - old_time < 0) { 345 CIRCQ_REMOVE(&c->c_list); 346 CIRCQ_INSERT(&c->c_list, &occ->cc_todo); 347 } 348 mutex_spin_exit(lock); 349 return; 350 } 351 352 cc = curcpu()->ci_data.cpu_callout; 353 if ((c->c_flags & CALLOUT_BOUND) != 0 || cc == occ || 354 !mutex_tryenter(&cc->cc_lock)) { 355 /* Leave on existing CPU. */ 356 c->c_time = to_ticks + occ->cc_ticks; 357 c->c_flags |= CALLOUT_PENDING; 358 CIRCQ_INSERT(&c->c_list, &occ->cc_todo); 359 } else { 360 /* Move to this CPU. */ 361 c->c_cpu = cc; 362 c->c_time = to_ticks + cc->cc_ticks; 363 c->c_flags |= CALLOUT_PENDING; 364 CIRCQ_INSERT(&c->c_list, &cc->cc_todo); 365 mutex_spin_exit(&cc->cc_lock); 366 } 367 mutex_spin_exit(lock); 368 } 369 370 /* 371 * callout_reset: 372 * 373 * Reset a callout structure with a new function and argument, and 374 * schedule it to run. 375 */ 376 void 377 callout_reset(callout_t *cs, int to_ticks, void (*func)(void *), void *arg) 378 { 379 callout_impl_t *c = (callout_impl_t *)cs; 380 kmutex_t *lock; 381 382 KASSERT(c->c_magic == CALLOUT_MAGIC); 383 384 lock = callout_lock(c); 385 c->c_func = func; 386 c->c_arg = arg; 387 callout_schedule_locked(c, lock, to_ticks); 388 } 389 390 /* 391 * callout_schedule: 392 * 393 * Schedule a callout to run. The function and argument must 394 * already be set in the callout structure. 395 */ 396 void 397 callout_schedule(callout_t *cs, int to_ticks) 398 { 399 callout_impl_t *c = (callout_impl_t *)cs; 400 kmutex_t *lock; 401 402 KASSERT(c->c_magic == CALLOUT_MAGIC); 403 404 lock = callout_lock(c); 405 callout_schedule_locked(c, lock, to_ticks); 406 } 407 408 /* 409 * callout_stop: 410 * 411 * Try to cancel a pending callout. It may be too late: the callout 412 * could be running on another CPU. If called from interrupt context, 413 * the callout could already be in progress at a lower priority. 414 */ 415 bool 416 callout_stop(callout_t *cs) 417 { 418 callout_impl_t *c = (callout_impl_t *)cs; 419 struct callout_cpu *cc; 420 kmutex_t *lock; 421 bool expired; 422 423 KASSERT(c->c_magic == CALLOUT_MAGIC); 424 425 lock = callout_lock(c); 426 427 if ((c->c_flags & CALLOUT_PENDING) != 0) 428 CIRCQ_REMOVE(&c->c_list); 429 expired = ((c->c_flags & CALLOUT_FIRED) != 0); 430 c->c_flags &= ~(CALLOUT_PENDING|CALLOUT_FIRED); 431 432 cc = c->c_cpu; 433 if (cc->cc_active == c) { 434 /* 435 * This is for non-MPSAFE callouts only. To synchronize 436 * effectively we must be called with kernel_lock held. 437 * It's also taken in callout_softclock. 438 */ 439 cc->cc_cancel = c; 440 } 441 442 mutex_spin_exit(lock); 443 444 return expired; 445 } 446 447 /* 448 * callout_halt: 449 * 450 * Cancel a pending callout. If in-flight, block until it completes. 451 * May not be called from a hard interrupt handler. If the callout 452 * can take locks, the caller of callout_halt() must not hold any of 453 * those locks, otherwise the two could deadlock. If 'interlock' is 454 * non-NULL and we must wait for the callout to complete, it will be 455 * released and re-acquired before returning. 456 */ 457 bool 458 callout_halt(callout_t *cs, void *interlock) 459 { 460 callout_impl_t *c = (callout_impl_t *)cs; 461 struct callout_cpu *cc; 462 struct lwp *l; 463 kmutex_t *lock, *relock; 464 bool expired; 465 466 KASSERT(c->c_magic == CALLOUT_MAGIC); 467 KASSERT(!cpu_intr_p()); 468 469 lock = callout_lock(c); 470 relock = NULL; 471 472 expired = ((c->c_flags & CALLOUT_FIRED) != 0); 473 if ((c->c_flags & CALLOUT_PENDING) != 0) 474 CIRCQ_REMOVE(&c->c_list); 475 c->c_flags &= ~(CALLOUT_PENDING|CALLOUT_FIRED); 476 477 l = curlwp; 478 for (;;) { 479 cc = c->c_cpu; 480 if (__predict_true(cc->cc_active != c || cc->cc_lwp == l)) 481 break; 482 if (interlock != NULL) { 483 /* 484 * Avoid potential scheduler lock order problems by 485 * dropping the interlock without the callout lock 486 * held. 487 */ 488 mutex_spin_exit(lock); 489 mutex_exit(interlock); 490 relock = interlock; 491 interlock = NULL; 492 } else { 493 /* XXX Better to do priority inheritance. */ 494 KASSERT(l->l_wchan == NULL); 495 cc->cc_nwait++; 496 cc->cc_ev_block.ev_count++; 497 l->l_kpriority = true; 498 sleepq_enter(&cc->cc_sleepq, l, &cc->cc_lock); 499 sleepq_enqueue(&cc->cc_sleepq, cc, "callout", 500 &sleep_syncobj); 501 sleepq_block(0, false); 502 } 503 lock = callout_lock(c); 504 } 505 506 mutex_spin_exit(lock); 507 if (__predict_false(relock != NULL)) 508 mutex_enter(relock); 509 510 return expired; 511 } 512 513 #ifdef notyet 514 /* 515 * callout_bind: 516 * 517 * Bind a callout so that it will only execute on one CPU. 518 * The callout must be stopped, and must be MPSAFE. 519 * 520 * XXX Disabled for now until it is decided how to handle 521 * offlined CPUs. We may want weak+strong binding. 522 */ 523 void 524 callout_bind(callout_t *cs, struct cpu_info *ci) 525 { 526 callout_impl_t *c = (callout_impl_t *)cs; 527 struct callout_cpu *cc; 528 kmutex_t *lock; 529 530 KASSERT((c->c_flags & CALLOUT_PENDING) == 0); 531 KASSERT(c->c_cpu->cc_active != c); 532 KASSERT(c->c_magic == CALLOUT_MAGIC); 533 KASSERT((c->c_flags & CALLOUT_MPSAFE) != 0); 534 535 lock = callout_lock(c); 536 cc = ci->ci_data.cpu_callout; 537 c->c_flags |= CALLOUT_BOUND; 538 if (c->c_cpu != cc) { 539 /* 540 * Assigning c_cpu effectively unlocks the callout 541 * structure, as we don't hold the new CPU's lock. 542 * Issue memory barrier to prevent accesses being 543 * reordered. 544 */ 545 membar_exit(); 546 c->c_cpu = cc; 547 } 548 mutex_spin_exit(lock); 549 } 550 #endif 551 552 void 553 callout_setfunc(callout_t *cs, void (*func)(void *), void *arg) 554 { 555 callout_impl_t *c = (callout_impl_t *)cs; 556 kmutex_t *lock; 557 558 KASSERT(c->c_magic == CALLOUT_MAGIC); 559 560 lock = callout_lock(c); 561 c->c_func = func; 562 c->c_arg = arg; 563 mutex_spin_exit(lock); 564 } 565 566 bool 567 callout_expired(callout_t *cs) 568 { 569 callout_impl_t *c = (callout_impl_t *)cs; 570 kmutex_t *lock; 571 bool rv; 572 573 KASSERT(c->c_magic == CALLOUT_MAGIC); 574 575 lock = callout_lock(c); 576 rv = ((c->c_flags & CALLOUT_FIRED) != 0); 577 mutex_spin_exit(lock); 578 579 return rv; 580 } 581 582 bool 583 callout_active(callout_t *cs) 584 { 585 callout_impl_t *c = (callout_impl_t *)cs; 586 kmutex_t *lock; 587 bool rv; 588 589 KASSERT(c->c_magic == CALLOUT_MAGIC); 590 591 lock = callout_lock(c); 592 rv = ((c->c_flags & (CALLOUT_PENDING|CALLOUT_FIRED)) != 0); 593 mutex_spin_exit(lock); 594 595 return rv; 596 } 597 598 bool 599 callout_pending(callout_t *cs) 600 { 601 callout_impl_t *c = (callout_impl_t *)cs; 602 kmutex_t *lock; 603 bool rv; 604 605 KASSERT(c->c_magic == CALLOUT_MAGIC); 606 607 lock = callout_lock(c); 608 rv = ((c->c_flags & CALLOUT_PENDING) != 0); 609 mutex_spin_exit(lock); 610 611 return rv; 612 } 613 614 bool 615 callout_invoking(callout_t *cs) 616 { 617 callout_impl_t *c = (callout_impl_t *)cs; 618 kmutex_t *lock; 619 bool rv; 620 621 KASSERT(c->c_magic == CALLOUT_MAGIC); 622 623 lock = callout_lock(c); 624 rv = ((c->c_flags & CALLOUT_INVOKING) != 0); 625 mutex_spin_exit(lock); 626 627 return rv; 628 } 629 630 void 631 callout_ack(callout_t *cs) 632 { 633 callout_impl_t *c = (callout_impl_t *)cs; 634 kmutex_t *lock; 635 636 KASSERT(c->c_magic == CALLOUT_MAGIC); 637 638 lock = callout_lock(c); 639 c->c_flags &= ~CALLOUT_INVOKING; 640 mutex_spin_exit(lock); 641 } 642 643 /* 644 * callout_hardclock: 645 * 646 * Called from hardclock() once every tick. We schedule a soft 647 * interrupt if there is work to be done. 648 */ 649 void 650 callout_hardclock(void) 651 { 652 struct callout_cpu *cc; 653 int needsoftclock, ticks; 654 655 cc = curcpu()->ci_data.cpu_callout; 656 mutex_spin_enter(&cc->cc_lock); 657 658 ticks = ++cc->cc_ticks; 659 660 MOVEBUCKET(cc, 0, ticks); 661 if (MASKWHEEL(0, ticks) == 0) { 662 MOVEBUCKET(cc, 1, ticks); 663 if (MASKWHEEL(1, ticks) == 0) { 664 MOVEBUCKET(cc, 2, ticks); 665 if (MASKWHEEL(2, ticks) == 0) 666 MOVEBUCKET(cc, 3, ticks); 667 } 668 } 669 670 needsoftclock = !CIRCQ_EMPTY(&cc->cc_todo); 671 mutex_spin_exit(&cc->cc_lock); 672 673 if (needsoftclock) 674 softint_schedule(callout_sih); 675 } 676 677 /* 678 * callout_softclock: 679 * 680 * Soft interrupt handler, scheduled above if there is work to 681 * be done. Callouts are made in soft interrupt context. 682 */ 683 static void 684 callout_softclock(void *v) 685 { 686 callout_impl_t *c; 687 struct callout_cpu *cc; 688 void (*func)(void *); 689 void *arg; 690 int mpsafe, count, ticks, delta; 691 lwp_t *l; 692 693 l = curlwp; 694 KASSERT(l->l_cpu == curcpu()); 695 cc = l->l_cpu->ci_data.cpu_callout; 696 697 mutex_spin_enter(&cc->cc_lock); 698 cc->cc_lwp = l; 699 while (!CIRCQ_EMPTY(&cc->cc_todo)) { 700 c = CIRCQ_FIRST(&cc->cc_todo); 701 KASSERT(c->c_magic == CALLOUT_MAGIC); 702 KASSERT(c->c_func != NULL); 703 KASSERT(c->c_cpu == cc); 704 KASSERT((c->c_flags & CALLOUT_PENDING) != 0); 705 KASSERT((c->c_flags & CALLOUT_FIRED) == 0); 706 CIRCQ_REMOVE(&c->c_list); 707 708 /* If due run it, otherwise insert it into the right bucket. */ 709 ticks = cc->cc_ticks; 710 delta = c->c_time - ticks; 711 if (delta > 0) { 712 CIRCQ_INSERT(&c->c_list, BUCKET(cc, delta, c->c_time)); 713 continue; 714 } 715 if (delta < 0) 716 cc->cc_ev_late.ev_count++; 717 718 c->c_flags ^= (CALLOUT_PENDING | CALLOUT_FIRED); 719 mpsafe = (c->c_flags & CALLOUT_MPSAFE); 720 func = c->c_func; 721 arg = c->c_arg; 722 cc->cc_active = c; 723 724 mutex_spin_exit(&cc->cc_lock); 725 if (!mpsafe) { 726 KERNEL_LOCK(1, NULL); 727 (*func)(arg); 728 KERNEL_UNLOCK_ONE(NULL); 729 } else 730 (*func)(arg); 731 mutex_spin_enter(&cc->cc_lock); 732 733 /* 734 * We can't touch 'c' here because it might be 735 * freed already. If LWPs waiting for callout 736 * to complete, awaken them. 737 */ 738 cc->cc_active = NULL; 739 if ((count = cc->cc_nwait) != 0) { 740 cc->cc_nwait = 0; 741 /* sleepq_wake() drops the lock. */ 742 sleepq_wake(&cc->cc_sleepq, cc, count, &cc->cc_lock); 743 mutex_spin_enter(&cc->cc_lock); 744 } 745 } 746 cc->cc_lwp = NULL; 747 mutex_spin_exit(&cc->cc_lock); 748 } 749 750 #ifdef DDB 751 static void 752 db_show_callout_bucket(struct callout_cpu *cc, struct callout_circq *bucket) 753 { 754 callout_impl_t *c; 755 db_expr_t offset; 756 const char *name; 757 static char question[] = "?"; 758 int b; 759 760 if (CIRCQ_EMPTY(bucket)) 761 return; 762 763 for (c = CIRCQ_FIRST(bucket); /*nothing*/; c = CIRCQ_NEXT(&c->c_list)) { 764 db_find_sym_and_offset((db_addr_t)(intptr_t)c->c_func, &name, 765 &offset); 766 name = name ? name : question; 767 b = (bucket - cc->cc_wheel); 768 if (b < 0) 769 b = -WHEELSIZE; 770 db_printf("%9d %2d/%-4d %16lx %s\n", 771 c->c_time - cc->cc_ticks, b / WHEELSIZE, b, 772 (u_long)c->c_arg, name); 773 if (CIRCQ_LAST(&c->c_list, bucket)) 774 break; 775 } 776 } 777 778 void 779 db_show_callout(db_expr_t addr, bool haddr, db_expr_t count, const char *modif) 780 { 781 CPU_INFO_ITERATOR cii; 782 struct callout_cpu *cc; 783 struct cpu_info *ci; 784 int b; 785 786 db_printf("hardclock_ticks now: %d\n", hardclock_ticks); 787 db_printf(" ticks wheel arg func\n"); 788 789 /* 790 * Don't lock the callwheel; all the other CPUs are paused 791 * anyhow, and we might be called in a circumstance where 792 * some other CPU was paused while holding the lock. 793 */ 794 for (CPU_INFO_FOREACH(cii, ci)) { 795 cc = ci->ci_data.cpu_callout; 796 db_show_callout_bucket(cc, &cc->cc_todo); 797 } 798 for (b = 0; b < BUCKETS; b++) { 799 for (CPU_INFO_FOREACH(cii, ci)) { 800 cc = ci->ci_data.cpu_callout; 801 db_show_callout_bucket(cc, &cc->cc_wheel[b]); 802 } 803 } 804 } 805 #endif /* DDB */ 806