1 /* $NetBSD: kern_timeout.c,v 1.57 2019/11/21 17:57:40 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 2003, 2006, 2007, 2008, 2009, 2019 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 1.57 2019/11/21 17:57:40 ad 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/lwp.h> 91 #include <sys/mutex.h> 92 #include <sys/proc.h> 93 #include <sys/sleepq.h> 94 #include <sys/syncobj.h> 95 #include <sys/evcnt.h> 96 #include <sys/intr.h> 97 #include <sys/cpu.h> 98 #include <sys/kmem.h> 99 100 #ifdef DDB 101 #include <machine/db_machdep.h> 102 #include <ddb/db_interface.h> 103 #include <ddb/db_access.h> 104 #include <ddb/db_cpu.h> 105 #include <ddb/db_sym.h> 106 #include <ddb/db_output.h> 107 #endif 108 109 #define BUCKETS 1024 110 #define WHEELSIZE 256 111 #define WHEELMASK 255 112 #define WHEELBITS 8 113 114 #define MASKWHEEL(wheel, time) (((time) >> ((wheel)*WHEELBITS)) & WHEELMASK) 115 116 #define BUCKET(cc, rel, abs) \ 117 (((rel) <= (1 << (2*WHEELBITS))) \ 118 ? ((rel) <= (1 << WHEELBITS)) \ 119 ? &(cc)->cc_wheel[MASKWHEEL(0, (abs))] \ 120 : &(cc)->cc_wheel[MASKWHEEL(1, (abs)) + WHEELSIZE] \ 121 : ((rel) <= (1 << (3*WHEELBITS))) \ 122 ? &(cc)->cc_wheel[MASKWHEEL(2, (abs)) + 2*WHEELSIZE] \ 123 : &(cc)->cc_wheel[MASKWHEEL(3, (abs)) + 3*WHEELSIZE]) 124 125 #define MOVEBUCKET(cc, wheel, time) \ 126 CIRCQ_APPEND(&(cc)->cc_todo, \ 127 &(cc)->cc_wheel[MASKWHEEL((wheel), (time)) + (wheel)*WHEELSIZE]) 128 129 /* 130 * Circular queue definitions. 131 */ 132 133 #define CIRCQ_INIT(list) \ 134 do { \ 135 (list)->cq_next_l = (list); \ 136 (list)->cq_prev_l = (list); \ 137 } while (/*CONSTCOND*/0) 138 139 #define CIRCQ_INSERT(elem, list) \ 140 do { \ 141 (elem)->cq_prev_e = (list)->cq_prev_e; \ 142 (elem)->cq_next_l = (list); \ 143 (list)->cq_prev_l->cq_next_l = (elem); \ 144 (list)->cq_prev_l = (elem); \ 145 } while (/*CONSTCOND*/0) 146 147 #define CIRCQ_APPEND(fst, snd) \ 148 do { \ 149 if (!CIRCQ_EMPTY(snd)) { \ 150 (fst)->cq_prev_l->cq_next_l = (snd)->cq_next_l; \ 151 (snd)->cq_next_l->cq_prev_l = (fst)->cq_prev_l; \ 152 (snd)->cq_prev_l->cq_next_l = (fst); \ 153 (fst)->cq_prev_l = (snd)->cq_prev_l; \ 154 CIRCQ_INIT(snd); \ 155 } \ 156 } while (/*CONSTCOND*/0) 157 158 #define CIRCQ_REMOVE(elem) \ 159 do { \ 160 (elem)->cq_next_l->cq_prev_e = (elem)->cq_prev_e; \ 161 (elem)->cq_prev_l->cq_next_e = (elem)->cq_next_e; \ 162 } while (/*CONSTCOND*/0) 163 164 #define CIRCQ_FIRST(list) ((list)->cq_next_e) 165 #define CIRCQ_NEXT(elem) ((elem)->cq_next_e) 166 #define CIRCQ_LAST(elem,list) ((elem)->cq_next_l == (list)) 167 #define CIRCQ_EMPTY(list) ((list)->cq_next_l == (list)) 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 #ifndef CRASH 186 187 static void callout_softclock(void *); 188 static void callout_wait(callout_impl_t *, void *, kmutex_t *); 189 190 static struct callout_cpu callout_cpu0 __cacheline_aligned; 191 static void *callout_sih __read_mostly; 192 193 static inline kmutex_t * 194 callout_lock(callout_impl_t *c) 195 { 196 struct callout_cpu *cc; 197 kmutex_t *lock; 198 199 for (;;) { 200 cc = c->c_cpu; 201 lock = cc->cc_lock; 202 mutex_spin_enter(lock); 203 if (__predict_true(cc == c->c_cpu)) 204 return lock; 205 mutex_spin_exit(lock); 206 } 207 } 208 209 /* 210 * callout_startup: 211 * 212 * Initialize the callout facility, called at system startup time. 213 * Do just enough to allow callouts to be safely registered. 214 */ 215 void 216 callout_startup(void) 217 { 218 struct callout_cpu *cc; 219 int b; 220 221 KASSERT(curcpu()->ci_data.cpu_callout == NULL); 222 223 cc = &callout_cpu0; 224 cc->cc_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_SCHED); 225 CIRCQ_INIT(&cc->cc_todo); 226 for (b = 0; b < BUCKETS; b++) 227 CIRCQ_INIT(&cc->cc_wheel[b]); 228 curcpu()->ci_data.cpu_callout = cc; 229 } 230 231 /* 232 * callout_init_cpu: 233 * 234 * Per-CPU initialization. 235 */ 236 CTASSERT(sizeof(callout_impl_t) <= sizeof(callout_t)); 237 238 void 239 callout_init_cpu(struct cpu_info *ci) 240 { 241 struct callout_cpu *cc; 242 int b; 243 244 if ((cc = ci->ci_data.cpu_callout) == NULL) { 245 cc = kmem_zalloc(sizeof(*cc), KM_SLEEP); 246 cc->cc_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_SCHED); 247 CIRCQ_INIT(&cc->cc_todo); 248 for (b = 0; b < BUCKETS; b++) 249 CIRCQ_INIT(&cc->cc_wheel[b]); 250 } else { 251 /* Boot CPU, one time only. */ 252 callout_sih = softint_establish(SOFTINT_CLOCK | SOFTINT_MPSAFE, 253 callout_softclock, NULL); 254 if (callout_sih == NULL) 255 panic("callout_init_cpu (2)"); 256 } 257 258 sleepq_init(&cc->cc_sleepq); 259 260 snprintf(cc->cc_name1, sizeof(cc->cc_name1), "late/%u", 261 cpu_index(ci)); 262 evcnt_attach_dynamic(&cc->cc_ev_late, EVCNT_TYPE_MISC, 263 NULL, "callout", cc->cc_name1); 264 265 snprintf(cc->cc_name2, sizeof(cc->cc_name2), "wait/%u", 266 cpu_index(ci)); 267 evcnt_attach_dynamic(&cc->cc_ev_block, EVCNT_TYPE_MISC, 268 NULL, "callout", cc->cc_name2); 269 270 ci->ci_data.cpu_callout = cc; 271 } 272 273 /* 274 * callout_init: 275 * 276 * Initialize a callout structure. This must be quick, so we fill 277 * only the minimum number of fields. 278 */ 279 void 280 callout_init(callout_t *cs, u_int flags) 281 { 282 callout_impl_t *c = (callout_impl_t *)cs; 283 struct callout_cpu *cc; 284 285 KASSERT((flags & ~CALLOUT_FLAGMASK) == 0); 286 287 cc = curcpu()->ci_data.cpu_callout; 288 c->c_func = NULL; 289 c->c_magic = CALLOUT_MAGIC; 290 if (__predict_true((flags & CALLOUT_MPSAFE) != 0 && cc != NULL)) { 291 c->c_flags = flags; 292 c->c_cpu = cc; 293 return; 294 } 295 c->c_flags = flags | CALLOUT_BOUND; 296 c->c_cpu = &callout_cpu0; 297 } 298 299 /* 300 * callout_destroy: 301 * 302 * Destroy a callout structure. The callout must be stopped. 303 */ 304 void 305 callout_destroy(callout_t *cs) 306 { 307 callout_impl_t *c = (callout_impl_t *)cs; 308 309 KASSERTMSG(c->c_magic == CALLOUT_MAGIC, 310 "callout %p: c_magic (%#x) != CALLOUT_MAGIC (%#x)", 311 c, c->c_magic, CALLOUT_MAGIC); 312 /* 313 * It's not necessary to lock in order to see the correct value 314 * of c->c_flags. If the callout could potentially have been 315 * running, the current thread should have stopped it. 316 */ 317 KASSERTMSG((c->c_flags & CALLOUT_PENDING) == 0, 318 "callout %p: c_func (%p) c_flags (%#x) destroyed from %p", 319 c, c->c_func, c->c_flags, __builtin_return_address(0)); 320 KASSERT(c->c_cpu->cc_lwp == curlwp || c->c_cpu->cc_active != c); 321 c->c_magic = 0; 322 } 323 324 /* 325 * callout_schedule_locked: 326 * 327 * Schedule a callout to run. The function and argument must 328 * already be set in the callout structure. Must be called with 329 * callout_lock. 330 */ 331 static void 332 callout_schedule_locked(callout_impl_t *c, kmutex_t *lock, int to_ticks) 333 { 334 struct callout_cpu *cc, *occ; 335 int old_time; 336 337 KASSERT(to_ticks >= 0); 338 KASSERT(c->c_func != NULL); 339 340 /* Initialize the time here, it won't change. */ 341 occ = c->c_cpu; 342 c->c_flags &= ~(CALLOUT_FIRED | CALLOUT_INVOKING); 343 344 /* 345 * If this timeout is already scheduled and now is moved 346 * earlier, reschedule it now. Otherwise leave it in place 347 * and let it be rescheduled later. 348 */ 349 if ((c->c_flags & CALLOUT_PENDING) != 0) { 350 /* Leave on existing CPU. */ 351 old_time = c->c_time; 352 c->c_time = to_ticks + occ->cc_ticks; 353 if (c->c_time - old_time < 0) { 354 CIRCQ_REMOVE(&c->c_list); 355 CIRCQ_INSERT(&c->c_list, &occ->cc_todo); 356 } 357 mutex_spin_exit(lock); 358 return; 359 } 360 361 cc = curcpu()->ci_data.cpu_callout; 362 if ((c->c_flags & CALLOUT_BOUND) != 0 || cc == occ || 363 !mutex_tryenter(cc->cc_lock)) { 364 /* Leave on existing CPU. */ 365 c->c_time = to_ticks + occ->cc_ticks; 366 c->c_flags |= CALLOUT_PENDING; 367 CIRCQ_INSERT(&c->c_list, &occ->cc_todo); 368 } else { 369 /* Move to this CPU. */ 370 c->c_cpu = cc; 371 c->c_time = to_ticks + cc->cc_ticks; 372 c->c_flags |= CALLOUT_PENDING; 373 CIRCQ_INSERT(&c->c_list, &cc->cc_todo); 374 mutex_spin_exit(cc->cc_lock); 375 } 376 mutex_spin_exit(lock); 377 } 378 379 /* 380 * callout_reset: 381 * 382 * Reset a callout structure with a new function and argument, and 383 * schedule it to run. 384 */ 385 void 386 callout_reset(callout_t *cs, int to_ticks, void (*func)(void *), void *arg) 387 { 388 callout_impl_t *c = (callout_impl_t *)cs; 389 kmutex_t *lock; 390 391 KASSERT(c->c_magic == CALLOUT_MAGIC); 392 KASSERT(func != NULL); 393 394 lock = callout_lock(c); 395 c->c_func = func; 396 c->c_arg = arg; 397 callout_schedule_locked(c, lock, to_ticks); 398 } 399 400 /* 401 * callout_schedule: 402 * 403 * Schedule a callout to run. The function and argument must 404 * already be set in the callout structure. 405 */ 406 void 407 callout_schedule(callout_t *cs, int to_ticks) 408 { 409 callout_impl_t *c = (callout_impl_t *)cs; 410 kmutex_t *lock; 411 412 KASSERT(c->c_magic == CALLOUT_MAGIC); 413 414 lock = callout_lock(c); 415 callout_schedule_locked(c, lock, to_ticks); 416 } 417 418 /* 419 * callout_stop: 420 * 421 * Try to cancel a pending callout. It may be too late: the callout 422 * could be running on another CPU. If called from interrupt context, 423 * the callout could already be in progress at a lower priority. 424 */ 425 bool 426 callout_stop(callout_t *cs) 427 { 428 callout_impl_t *c = (callout_impl_t *)cs; 429 struct callout_cpu *cc; 430 kmutex_t *lock; 431 bool expired; 432 433 KASSERT(c->c_magic == CALLOUT_MAGIC); 434 435 lock = callout_lock(c); 436 437 if ((c->c_flags & CALLOUT_PENDING) != 0) 438 CIRCQ_REMOVE(&c->c_list); 439 expired = ((c->c_flags & CALLOUT_FIRED) != 0); 440 c->c_flags &= ~(CALLOUT_PENDING|CALLOUT_FIRED); 441 442 cc = c->c_cpu; 443 if (cc->cc_active == c) { 444 /* 445 * This is for non-MPSAFE callouts only. To synchronize 446 * effectively we must be called with kernel_lock held. 447 * It's also taken in callout_softclock. 448 */ 449 cc->cc_cancel = c; 450 } 451 452 mutex_spin_exit(lock); 453 454 return expired; 455 } 456 457 /* 458 * callout_halt: 459 * 460 * Cancel a pending callout. If in-flight, block until it completes. 461 * May not be called from a hard interrupt handler. If the callout 462 * can take locks, the caller of callout_halt() must not hold any of 463 * those locks, otherwise the two could deadlock. If 'interlock' is 464 * non-NULL and we must wait for the callout to complete, it will be 465 * released and re-acquired before returning. 466 */ 467 bool 468 callout_halt(callout_t *cs, void *interlock) 469 { 470 callout_impl_t *c = (callout_impl_t *)cs; 471 kmutex_t *lock; 472 int flags; 473 474 KASSERT(c->c_magic == CALLOUT_MAGIC); 475 KASSERT(!cpu_intr_p()); 476 KASSERT(interlock == NULL || mutex_owned(interlock)); 477 478 /* Fast path. */ 479 lock = callout_lock(c); 480 flags = c->c_flags; 481 if ((flags & CALLOUT_PENDING) != 0) 482 CIRCQ_REMOVE(&c->c_list); 483 c->c_flags = flags & ~(CALLOUT_PENDING|CALLOUT_FIRED); 484 if (__predict_false(flags & CALLOUT_FIRED)) { 485 callout_wait(c, interlock, lock); 486 return true; 487 } 488 mutex_spin_exit(lock); 489 return false; 490 } 491 492 /* 493 * callout_wait: 494 * 495 * Slow path for callout_halt(). Deliberately marked __noinline to 496 * prevent unneeded overhead in the caller. 497 */ 498 static void __noinline 499 callout_wait(callout_impl_t *c, void *interlock, kmutex_t *lock) 500 { 501 struct callout_cpu *cc; 502 struct lwp *l; 503 kmutex_t *relock; 504 505 l = curlwp; 506 relock = NULL; 507 for (;;) { 508 cc = c->c_cpu; 509 if (__predict_true(cc->cc_active != c || cc->cc_lwp == l)) 510 break; 511 if (interlock != NULL) { 512 /* 513 * Avoid potential scheduler lock order problems by 514 * dropping the interlock without the callout lock 515 * held. 516 */ 517 mutex_spin_exit(lock); 518 mutex_exit(interlock); 519 relock = interlock; 520 interlock = NULL; 521 } else { 522 /* XXX Better to do priority inheritance. */ 523 KASSERT(l->l_wchan == NULL); 524 cc->cc_nwait++; 525 cc->cc_ev_block.ev_count++; 526 l->l_kpriority = true; 527 sleepq_enter(&cc->cc_sleepq, l, cc->cc_lock); 528 sleepq_enqueue(&cc->cc_sleepq, cc, "callout", 529 &sleep_syncobj); 530 sleepq_block(0, false); 531 } 532 lock = callout_lock(c); 533 } 534 535 mutex_spin_exit(lock); 536 if (__predict_false(relock != NULL)) 537 mutex_enter(relock); 538 } 539 540 #ifdef notyet 541 /* 542 * callout_bind: 543 * 544 * Bind a callout so that it will only execute on one CPU. 545 * The callout must be stopped, and must be MPSAFE. 546 * 547 * XXX Disabled for now until it is decided how to handle 548 * offlined CPUs. We may want weak+strong binding. 549 */ 550 void 551 callout_bind(callout_t *cs, struct cpu_info *ci) 552 { 553 callout_impl_t *c = (callout_impl_t *)cs; 554 struct callout_cpu *cc; 555 kmutex_t *lock; 556 557 KASSERT((c->c_flags & CALLOUT_PENDING) == 0); 558 KASSERT(c->c_cpu->cc_active != c); 559 KASSERT(c->c_magic == CALLOUT_MAGIC); 560 KASSERT((c->c_flags & CALLOUT_MPSAFE) != 0); 561 562 lock = callout_lock(c); 563 cc = ci->ci_data.cpu_callout; 564 c->c_flags |= CALLOUT_BOUND; 565 if (c->c_cpu != cc) { 566 /* 567 * Assigning c_cpu effectively unlocks the callout 568 * structure, as we don't hold the new CPU's lock. 569 * Issue memory barrier to prevent accesses being 570 * reordered. 571 */ 572 membar_exit(); 573 c->c_cpu = cc; 574 } 575 mutex_spin_exit(lock); 576 } 577 #endif 578 579 void 580 callout_setfunc(callout_t *cs, void (*func)(void *), void *arg) 581 { 582 callout_impl_t *c = (callout_impl_t *)cs; 583 kmutex_t *lock; 584 585 KASSERT(c->c_magic == CALLOUT_MAGIC); 586 KASSERT(func != NULL); 587 588 lock = callout_lock(c); 589 c->c_func = func; 590 c->c_arg = arg; 591 mutex_spin_exit(lock); 592 } 593 594 bool 595 callout_expired(callout_t *cs) 596 { 597 callout_impl_t *c = (callout_impl_t *)cs; 598 kmutex_t *lock; 599 bool rv; 600 601 KASSERT(c->c_magic == CALLOUT_MAGIC); 602 603 lock = callout_lock(c); 604 rv = ((c->c_flags & CALLOUT_FIRED) != 0); 605 mutex_spin_exit(lock); 606 607 return rv; 608 } 609 610 bool 611 callout_active(callout_t *cs) 612 { 613 callout_impl_t *c = (callout_impl_t *)cs; 614 kmutex_t *lock; 615 bool rv; 616 617 KASSERT(c->c_magic == CALLOUT_MAGIC); 618 619 lock = callout_lock(c); 620 rv = ((c->c_flags & (CALLOUT_PENDING|CALLOUT_FIRED)) != 0); 621 mutex_spin_exit(lock); 622 623 return rv; 624 } 625 626 bool 627 callout_pending(callout_t *cs) 628 { 629 callout_impl_t *c = (callout_impl_t *)cs; 630 kmutex_t *lock; 631 bool rv; 632 633 KASSERT(c->c_magic == CALLOUT_MAGIC); 634 635 lock = callout_lock(c); 636 rv = ((c->c_flags & CALLOUT_PENDING) != 0); 637 mutex_spin_exit(lock); 638 639 return rv; 640 } 641 642 bool 643 callout_invoking(callout_t *cs) 644 { 645 callout_impl_t *c = (callout_impl_t *)cs; 646 kmutex_t *lock; 647 bool rv; 648 649 KASSERT(c->c_magic == CALLOUT_MAGIC); 650 651 lock = callout_lock(c); 652 rv = ((c->c_flags & CALLOUT_INVOKING) != 0); 653 mutex_spin_exit(lock); 654 655 return rv; 656 } 657 658 void 659 callout_ack(callout_t *cs) 660 { 661 callout_impl_t *c = (callout_impl_t *)cs; 662 kmutex_t *lock; 663 664 KASSERT(c->c_magic == CALLOUT_MAGIC); 665 666 lock = callout_lock(c); 667 c->c_flags &= ~CALLOUT_INVOKING; 668 mutex_spin_exit(lock); 669 } 670 671 /* 672 * callout_hardclock: 673 * 674 * Called from hardclock() once every tick. We schedule a soft 675 * interrupt if there is work to be done. 676 */ 677 void 678 callout_hardclock(void) 679 { 680 struct callout_cpu *cc; 681 int needsoftclock, ticks; 682 683 cc = curcpu()->ci_data.cpu_callout; 684 mutex_spin_enter(cc->cc_lock); 685 686 ticks = ++cc->cc_ticks; 687 688 MOVEBUCKET(cc, 0, ticks); 689 if (MASKWHEEL(0, ticks) == 0) { 690 MOVEBUCKET(cc, 1, ticks); 691 if (MASKWHEEL(1, ticks) == 0) { 692 MOVEBUCKET(cc, 2, ticks); 693 if (MASKWHEEL(2, ticks) == 0) 694 MOVEBUCKET(cc, 3, ticks); 695 } 696 } 697 698 needsoftclock = !CIRCQ_EMPTY(&cc->cc_todo); 699 mutex_spin_exit(cc->cc_lock); 700 701 if (needsoftclock) 702 softint_schedule(callout_sih); 703 } 704 705 /* 706 * callout_softclock: 707 * 708 * Soft interrupt handler, scheduled above if there is work to 709 * be done. Callouts are made in soft interrupt context. 710 */ 711 static void 712 callout_softclock(void *v) 713 { 714 callout_impl_t *c; 715 struct callout_cpu *cc; 716 void (*func)(void *); 717 void *arg; 718 int mpsafe, count, ticks, delta; 719 lwp_t *l; 720 721 l = curlwp; 722 KASSERT(l->l_cpu == curcpu()); 723 cc = l->l_cpu->ci_data.cpu_callout; 724 725 mutex_spin_enter(cc->cc_lock); 726 cc->cc_lwp = l; 727 while (!CIRCQ_EMPTY(&cc->cc_todo)) { 728 c = CIRCQ_FIRST(&cc->cc_todo); 729 KASSERT(c->c_magic == CALLOUT_MAGIC); 730 KASSERT(c->c_func != NULL); 731 KASSERT(c->c_cpu == cc); 732 KASSERT((c->c_flags & CALLOUT_PENDING) != 0); 733 KASSERT((c->c_flags & CALLOUT_FIRED) == 0); 734 CIRCQ_REMOVE(&c->c_list); 735 736 /* If due run it, otherwise insert it into the right bucket. */ 737 ticks = cc->cc_ticks; 738 delta = (int)((unsigned)c->c_time - (unsigned)ticks); 739 if (delta > 0) { 740 CIRCQ_INSERT(&c->c_list, BUCKET(cc, delta, c->c_time)); 741 continue; 742 } 743 if (delta < 0) 744 cc->cc_ev_late.ev_count++; 745 746 c->c_flags = (c->c_flags & ~CALLOUT_PENDING) | 747 (CALLOUT_FIRED | CALLOUT_INVOKING); 748 mpsafe = (c->c_flags & CALLOUT_MPSAFE); 749 func = c->c_func; 750 arg = c->c_arg; 751 cc->cc_active = c; 752 753 mutex_spin_exit(cc->cc_lock); 754 KASSERT(func != NULL); 755 if (__predict_false(!mpsafe)) { 756 KERNEL_LOCK(1, NULL); 757 (*func)(arg); 758 KERNEL_UNLOCK_ONE(NULL); 759 } else 760 (*func)(arg); 761 mutex_spin_enter(cc->cc_lock); 762 763 /* 764 * We can't touch 'c' here because it might be 765 * freed already. If LWPs waiting for callout 766 * to complete, awaken them. 767 */ 768 cc->cc_active = NULL; 769 if ((count = cc->cc_nwait) != 0) { 770 cc->cc_nwait = 0; 771 /* sleepq_wake() drops the lock. */ 772 sleepq_wake(&cc->cc_sleepq, cc, count, cc->cc_lock); 773 mutex_spin_enter(cc->cc_lock); 774 } 775 } 776 cc->cc_lwp = NULL; 777 mutex_spin_exit(cc->cc_lock); 778 } 779 #endif 780 781 #ifdef DDB 782 static void 783 db_show_callout_bucket(struct callout_cpu *cc, struct callout_circq *kbucket, 784 struct callout_circq *bucket) 785 { 786 callout_impl_t *c, ci; 787 db_expr_t offset; 788 const char *name; 789 static char question[] = "?"; 790 int b; 791 792 if (CIRCQ_LAST(bucket, kbucket)) 793 return; 794 795 for (c = CIRCQ_FIRST(bucket); /*nothing*/; c = CIRCQ_NEXT(&c->c_list)) { 796 db_read_bytes((db_addr_t)c, sizeof(ci), (char *)&ci); 797 c = &ci; 798 db_find_sym_and_offset((db_addr_t)(intptr_t)c->c_func, &name, 799 &offset); 800 name = name ? name : question; 801 b = (bucket - cc->cc_wheel); 802 if (b < 0) 803 b = -WHEELSIZE; 804 db_printf("%9d %2d/%-4d %16lx %s\n", 805 c->c_time - cc->cc_ticks, b / WHEELSIZE, b, 806 (u_long)c->c_arg, name); 807 if (CIRCQ_LAST(&c->c_list, kbucket)) 808 break; 809 } 810 } 811 812 void 813 db_show_callout(db_expr_t addr, bool haddr, db_expr_t count, const char *modif) 814 { 815 struct callout_cpu *cc, ccb; 816 struct cpu_info *ci, cib; 817 int b; 818 819 #ifndef CRASH 820 db_printf("hardclock_ticks now: %d\n", hardclock_ticks); 821 #endif 822 db_printf(" ticks wheel arg func\n"); 823 824 /* 825 * Don't lock the callwheel; all the other CPUs are paused 826 * anyhow, and we might be called in a circumstance where 827 * some other CPU was paused while holding the lock. 828 */ 829 for (ci = db_cpu_first(); ci != NULL; ci = db_cpu_next(ci)) { 830 db_read_bytes((db_addr_t)ci, sizeof(cib), (char *)&cib); 831 cc = cib.ci_data.cpu_callout; 832 db_read_bytes((db_addr_t)cc, sizeof(ccb), (char *)&ccb); 833 db_show_callout_bucket(&ccb, &cc->cc_todo, &ccb.cc_todo); 834 } 835 for (b = 0; b < BUCKETS; b++) { 836 for (ci = db_cpu_first(); ci != NULL; ci = db_cpu_next(ci)) { 837 db_read_bytes((db_addr_t)ci, sizeof(cib), (char *)&cib); 838 cc = cib.ci_data.cpu_callout; 839 db_read_bytes((db_addr_t)cc, sizeof(ccb), (char *)&ccb); 840 db_show_callout_bucket(&ccb, &cc->cc_wheel[b], 841 &ccb.cc_wheel[b]); 842 } 843 } 844 } 845 #endif /* DDB */ 846