1 /* $NetBSD: kern_timeout.c,v 1.61 2020/04/19 20:35:29 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 1.61 2020/04/19 20:35:29 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 "pending callout %p: c_func (%p) c_flags (%#x) destroyed from %p", 319 c, c->c_func, c->c_flags, __builtin_return_address(0)); 320 KASSERTMSG(c->c_cpu->cc_lwp == curlwp || c->c_cpu->cc_active != c, 321 "running callout %p: c_func (%p) c_flags (%#x) destroyed from %p", 322 c, c->c_func, c->c_flags, __builtin_return_address(0)); 323 c->c_magic = 0; 324 } 325 326 /* 327 * callout_schedule_locked: 328 * 329 * Schedule a callout to run. The function and argument must 330 * already be set in the callout structure. Must be called with 331 * callout_lock. 332 */ 333 static void 334 callout_schedule_locked(callout_impl_t *c, kmutex_t *lock, int to_ticks) 335 { 336 struct callout_cpu *cc, *occ; 337 int old_time; 338 339 KASSERT(to_ticks >= 0); 340 KASSERT(c->c_func != NULL); 341 342 /* Initialize the time here, it won't change. */ 343 occ = c->c_cpu; 344 c->c_flags &= ~(CALLOUT_FIRED | CALLOUT_INVOKING); 345 346 /* 347 * If this timeout is already scheduled and now is moved 348 * earlier, reschedule it now. Otherwise leave it in place 349 * and let it be rescheduled later. 350 */ 351 if ((c->c_flags & CALLOUT_PENDING) != 0) { 352 /* Leave on existing CPU. */ 353 old_time = c->c_time; 354 c->c_time = to_ticks + occ->cc_ticks; 355 if (c->c_time - old_time < 0) { 356 CIRCQ_REMOVE(&c->c_list); 357 CIRCQ_INSERT(&c->c_list, &occ->cc_todo); 358 } 359 mutex_spin_exit(lock); 360 return; 361 } 362 363 cc = curcpu()->ci_data.cpu_callout; 364 if ((c->c_flags & CALLOUT_BOUND) != 0 || cc == occ || 365 !mutex_tryenter(cc->cc_lock)) { 366 /* Leave on existing CPU. */ 367 c->c_time = to_ticks + occ->cc_ticks; 368 c->c_flags |= CALLOUT_PENDING; 369 CIRCQ_INSERT(&c->c_list, &occ->cc_todo); 370 } else { 371 /* Move to this CPU. */ 372 c->c_cpu = cc; 373 c->c_time = to_ticks + cc->cc_ticks; 374 c->c_flags |= CALLOUT_PENDING; 375 CIRCQ_INSERT(&c->c_list, &cc->cc_todo); 376 mutex_spin_exit(cc->cc_lock); 377 } 378 mutex_spin_exit(lock); 379 } 380 381 /* 382 * callout_reset: 383 * 384 * Reset a callout structure with a new function and argument, and 385 * schedule it to run. 386 */ 387 void 388 callout_reset(callout_t *cs, int to_ticks, void (*func)(void *), void *arg) 389 { 390 callout_impl_t *c = (callout_impl_t *)cs; 391 kmutex_t *lock; 392 393 KASSERT(c->c_magic == CALLOUT_MAGIC); 394 KASSERT(func != NULL); 395 396 lock = callout_lock(c); 397 c->c_func = func; 398 c->c_arg = arg; 399 callout_schedule_locked(c, lock, to_ticks); 400 } 401 402 /* 403 * callout_schedule: 404 * 405 * Schedule a callout to run. The function and argument must 406 * already be set in the callout structure. 407 */ 408 void 409 callout_schedule(callout_t *cs, int to_ticks) 410 { 411 callout_impl_t *c = (callout_impl_t *)cs; 412 kmutex_t *lock; 413 414 KASSERT(c->c_magic == CALLOUT_MAGIC); 415 416 lock = callout_lock(c); 417 callout_schedule_locked(c, lock, to_ticks); 418 } 419 420 /* 421 * callout_stop: 422 * 423 * Try to cancel a pending callout. It may be too late: the callout 424 * could be running on another CPU. If called from interrupt context, 425 * the callout could already be in progress at a lower priority. 426 */ 427 bool 428 callout_stop(callout_t *cs) 429 { 430 callout_impl_t *c = (callout_impl_t *)cs; 431 struct callout_cpu *cc; 432 kmutex_t *lock; 433 bool expired; 434 435 KASSERT(c->c_magic == CALLOUT_MAGIC); 436 437 lock = callout_lock(c); 438 439 if ((c->c_flags & CALLOUT_PENDING) != 0) 440 CIRCQ_REMOVE(&c->c_list); 441 expired = ((c->c_flags & CALLOUT_FIRED) != 0); 442 c->c_flags &= ~(CALLOUT_PENDING|CALLOUT_FIRED); 443 444 cc = c->c_cpu; 445 if (cc->cc_active == c) { 446 /* 447 * This is for non-MPSAFE callouts only. To synchronize 448 * effectively we must be called with kernel_lock held. 449 * It's also taken in callout_softclock. 450 */ 451 cc->cc_cancel = c; 452 } 453 454 mutex_spin_exit(lock); 455 456 return expired; 457 } 458 459 /* 460 * callout_halt: 461 * 462 * Cancel a pending callout. If in-flight, block until it completes. 463 * May not be called from a hard interrupt handler. If the callout 464 * can take locks, the caller of callout_halt() must not hold any of 465 * those locks, otherwise the two could deadlock. If 'interlock' is 466 * non-NULL and we must wait for the callout to complete, it will be 467 * released and re-acquired before returning. 468 */ 469 bool 470 callout_halt(callout_t *cs, void *interlock) 471 { 472 callout_impl_t *c = (callout_impl_t *)cs; 473 kmutex_t *lock; 474 int flags; 475 476 KASSERT(c->c_magic == CALLOUT_MAGIC); 477 KASSERT(!cpu_intr_p()); 478 KASSERT(interlock == NULL || mutex_owned(interlock)); 479 480 /* Fast path. */ 481 lock = callout_lock(c); 482 flags = c->c_flags; 483 if ((flags & CALLOUT_PENDING) != 0) 484 CIRCQ_REMOVE(&c->c_list); 485 c->c_flags = flags & ~(CALLOUT_PENDING|CALLOUT_FIRED); 486 if (__predict_false(flags & CALLOUT_FIRED)) { 487 callout_wait(c, interlock, lock); 488 return true; 489 } 490 mutex_spin_exit(lock); 491 return false; 492 } 493 494 /* 495 * callout_wait: 496 * 497 * Slow path for callout_halt(). Deliberately marked __noinline to 498 * prevent unneeded overhead in the caller. 499 */ 500 static void __noinline 501 callout_wait(callout_impl_t *c, void *interlock, kmutex_t *lock) 502 { 503 struct callout_cpu *cc; 504 struct lwp *l; 505 kmutex_t *relock; 506 507 l = curlwp; 508 relock = NULL; 509 for (;;) { 510 /* 511 * At this point we know the callout is not pending, but it 512 * could be running on a CPU somewhere. That can be curcpu 513 * in a few cases: 514 * 515 * - curlwp is a higher priority soft interrupt 516 * - the callout blocked on a lock and is currently asleep 517 * - the callout itself has called callout_halt() (nice!) 518 */ 519 cc = c->c_cpu; 520 if (__predict_true(cc->cc_active != c || cc->cc_lwp == l)) 521 break; 522 523 /* It's running - need to wait for it to complete. */ 524 if (interlock != NULL) { 525 /* 526 * Avoid potential scheduler lock order problems by 527 * dropping the interlock without the callout lock 528 * held; then retry. 529 */ 530 mutex_spin_exit(lock); 531 mutex_exit(interlock); 532 relock = interlock; 533 interlock = NULL; 534 } else { 535 /* XXX Better to do priority inheritance. */ 536 KASSERT(l->l_wchan == NULL); 537 cc->cc_nwait++; 538 cc->cc_ev_block.ev_count++; 539 l->l_kpriority = true; 540 sleepq_enter(&cc->cc_sleepq, l, cc->cc_lock); 541 sleepq_enqueue(&cc->cc_sleepq, cc, "callout", 542 &sleep_syncobj, false); 543 sleepq_block(0, false); 544 } 545 546 /* 547 * Re-lock the callout and check the state of play again. 548 * It's a common design pattern for callouts to re-schedule 549 * themselves so put a stop to it again if needed. 550 */ 551 lock = callout_lock(c); 552 if ((c->c_flags & CALLOUT_PENDING) != 0) 553 CIRCQ_REMOVE(&c->c_list); 554 c->c_flags &= ~(CALLOUT_PENDING|CALLOUT_FIRED); 555 } 556 557 mutex_spin_exit(lock); 558 if (__predict_false(relock != NULL)) 559 mutex_enter(relock); 560 } 561 562 #ifdef notyet 563 /* 564 * callout_bind: 565 * 566 * Bind a callout so that it will only execute on one CPU. 567 * The callout must be stopped, and must be MPSAFE. 568 * 569 * XXX Disabled for now until it is decided how to handle 570 * offlined CPUs. We may want weak+strong binding. 571 */ 572 void 573 callout_bind(callout_t *cs, struct cpu_info *ci) 574 { 575 callout_impl_t *c = (callout_impl_t *)cs; 576 struct callout_cpu *cc; 577 kmutex_t *lock; 578 579 KASSERT((c->c_flags & CALLOUT_PENDING) == 0); 580 KASSERT(c->c_cpu->cc_active != c); 581 KASSERT(c->c_magic == CALLOUT_MAGIC); 582 KASSERT((c->c_flags & CALLOUT_MPSAFE) != 0); 583 584 lock = callout_lock(c); 585 cc = ci->ci_data.cpu_callout; 586 c->c_flags |= CALLOUT_BOUND; 587 if (c->c_cpu != cc) { 588 /* 589 * Assigning c_cpu effectively unlocks the callout 590 * structure, as we don't hold the new CPU's lock. 591 * Issue memory barrier to prevent accesses being 592 * reordered. 593 */ 594 membar_exit(); 595 c->c_cpu = cc; 596 } 597 mutex_spin_exit(lock); 598 } 599 #endif 600 601 void 602 callout_setfunc(callout_t *cs, void (*func)(void *), void *arg) 603 { 604 callout_impl_t *c = (callout_impl_t *)cs; 605 kmutex_t *lock; 606 607 KASSERT(c->c_magic == CALLOUT_MAGIC); 608 KASSERT(func != NULL); 609 610 lock = callout_lock(c); 611 c->c_func = func; 612 c->c_arg = arg; 613 mutex_spin_exit(lock); 614 } 615 616 bool 617 callout_expired(callout_t *cs) 618 { 619 callout_impl_t *c = (callout_impl_t *)cs; 620 kmutex_t *lock; 621 bool rv; 622 623 KASSERT(c->c_magic == CALLOUT_MAGIC); 624 625 lock = callout_lock(c); 626 rv = ((c->c_flags & CALLOUT_FIRED) != 0); 627 mutex_spin_exit(lock); 628 629 return rv; 630 } 631 632 bool 633 callout_active(callout_t *cs) 634 { 635 callout_impl_t *c = (callout_impl_t *)cs; 636 kmutex_t *lock; 637 bool rv; 638 639 KASSERT(c->c_magic == CALLOUT_MAGIC); 640 641 lock = callout_lock(c); 642 rv = ((c->c_flags & (CALLOUT_PENDING|CALLOUT_FIRED)) != 0); 643 mutex_spin_exit(lock); 644 645 return rv; 646 } 647 648 bool 649 callout_pending(callout_t *cs) 650 { 651 callout_impl_t *c = (callout_impl_t *)cs; 652 kmutex_t *lock; 653 bool rv; 654 655 KASSERT(c->c_magic == CALLOUT_MAGIC); 656 657 lock = callout_lock(c); 658 rv = ((c->c_flags & CALLOUT_PENDING) != 0); 659 mutex_spin_exit(lock); 660 661 return rv; 662 } 663 664 bool 665 callout_invoking(callout_t *cs) 666 { 667 callout_impl_t *c = (callout_impl_t *)cs; 668 kmutex_t *lock; 669 bool rv; 670 671 KASSERT(c->c_magic == CALLOUT_MAGIC); 672 673 lock = callout_lock(c); 674 rv = ((c->c_flags & CALLOUT_INVOKING) != 0); 675 mutex_spin_exit(lock); 676 677 return rv; 678 } 679 680 void 681 callout_ack(callout_t *cs) 682 { 683 callout_impl_t *c = (callout_impl_t *)cs; 684 kmutex_t *lock; 685 686 KASSERT(c->c_magic == CALLOUT_MAGIC); 687 688 lock = callout_lock(c); 689 c->c_flags &= ~CALLOUT_INVOKING; 690 mutex_spin_exit(lock); 691 } 692 693 /* 694 * callout_hardclock: 695 * 696 * Called from hardclock() once every tick. We schedule a soft 697 * interrupt if there is work to be done. 698 */ 699 void 700 callout_hardclock(void) 701 { 702 struct callout_cpu *cc; 703 int needsoftclock, ticks; 704 705 cc = curcpu()->ci_data.cpu_callout; 706 mutex_spin_enter(cc->cc_lock); 707 708 ticks = ++cc->cc_ticks; 709 710 MOVEBUCKET(cc, 0, ticks); 711 if (MASKWHEEL(0, ticks) == 0) { 712 MOVEBUCKET(cc, 1, ticks); 713 if (MASKWHEEL(1, ticks) == 0) { 714 MOVEBUCKET(cc, 2, ticks); 715 if (MASKWHEEL(2, ticks) == 0) 716 MOVEBUCKET(cc, 3, ticks); 717 } 718 } 719 720 needsoftclock = !CIRCQ_EMPTY(&cc->cc_todo); 721 mutex_spin_exit(cc->cc_lock); 722 723 if (needsoftclock) 724 softint_schedule(callout_sih); 725 } 726 727 /* 728 * callout_softclock: 729 * 730 * Soft interrupt handler, scheduled above if there is work to 731 * be done. Callouts are made in soft interrupt context. 732 */ 733 static void 734 callout_softclock(void *v) 735 { 736 callout_impl_t *c; 737 struct callout_cpu *cc; 738 void (*func)(void *); 739 void *arg; 740 int mpsafe, count, ticks, delta; 741 lwp_t *l; 742 743 l = curlwp; 744 KASSERT(l->l_cpu == curcpu()); 745 cc = l->l_cpu->ci_data.cpu_callout; 746 747 mutex_spin_enter(cc->cc_lock); 748 cc->cc_lwp = l; 749 while (!CIRCQ_EMPTY(&cc->cc_todo)) { 750 c = CIRCQ_FIRST(&cc->cc_todo); 751 KASSERT(c->c_magic == CALLOUT_MAGIC); 752 KASSERT(c->c_func != NULL); 753 KASSERT(c->c_cpu == cc); 754 KASSERT((c->c_flags & CALLOUT_PENDING) != 0); 755 KASSERT((c->c_flags & CALLOUT_FIRED) == 0); 756 CIRCQ_REMOVE(&c->c_list); 757 758 /* If due run it, otherwise insert it into the right bucket. */ 759 ticks = cc->cc_ticks; 760 delta = (int)((unsigned)c->c_time - (unsigned)ticks); 761 if (delta > 0) { 762 CIRCQ_INSERT(&c->c_list, BUCKET(cc, delta, c->c_time)); 763 continue; 764 } 765 if (delta < 0) 766 cc->cc_ev_late.ev_count++; 767 768 c->c_flags = (c->c_flags & ~CALLOUT_PENDING) | 769 (CALLOUT_FIRED | CALLOUT_INVOKING); 770 mpsafe = (c->c_flags & CALLOUT_MPSAFE); 771 func = c->c_func; 772 arg = c->c_arg; 773 cc->cc_active = c; 774 775 mutex_spin_exit(cc->cc_lock); 776 KASSERT(func != NULL); 777 if (__predict_false(!mpsafe)) { 778 KERNEL_LOCK(1, NULL); 779 (*func)(arg); 780 KERNEL_UNLOCK_ONE(NULL); 781 } else 782 (*func)(arg); 783 mutex_spin_enter(cc->cc_lock); 784 785 /* 786 * We can't touch 'c' here because it might be 787 * freed already. If LWPs waiting for callout 788 * to complete, awaken them. 789 */ 790 cc->cc_active = NULL; 791 if ((count = cc->cc_nwait) != 0) { 792 cc->cc_nwait = 0; 793 /* sleepq_wake() drops the lock. */ 794 sleepq_wake(&cc->cc_sleepq, cc, count, cc->cc_lock); 795 mutex_spin_enter(cc->cc_lock); 796 } 797 } 798 cc->cc_lwp = NULL; 799 mutex_spin_exit(cc->cc_lock); 800 } 801 #endif 802 803 #ifdef DDB 804 static void 805 db_show_callout_bucket(struct callout_cpu *cc, struct callout_circq *kbucket, 806 struct callout_circq *bucket) 807 { 808 callout_impl_t *c, ci; 809 db_expr_t offset; 810 const char *name; 811 static char question[] = "?"; 812 int b; 813 814 if (CIRCQ_LAST(bucket, kbucket)) 815 return; 816 817 for (c = CIRCQ_FIRST(bucket); /*nothing*/; c = CIRCQ_NEXT(&c->c_list)) { 818 db_read_bytes((db_addr_t)c, sizeof(ci), (char *)&ci); 819 c = &ci; 820 db_find_sym_and_offset((db_addr_t)(intptr_t)c->c_func, &name, 821 &offset); 822 name = name ? name : question; 823 b = (bucket - cc->cc_wheel); 824 if (b < 0) 825 b = -WHEELSIZE; 826 db_printf("%9d %2d/%-4d %16lx %s\n", 827 c->c_time - cc->cc_ticks, b / WHEELSIZE, b, 828 (u_long)c->c_arg, name); 829 if (CIRCQ_LAST(&c->c_list, kbucket)) 830 break; 831 } 832 } 833 834 void 835 db_show_callout(db_expr_t addr, bool haddr, db_expr_t count, const char *modif) 836 { 837 struct callout_cpu *cc, ccb; 838 struct cpu_info *ci, cib; 839 int b; 840 841 #ifndef CRASH 842 db_printf("hardclock_ticks now: %d\n", getticks()); 843 #endif 844 db_printf(" ticks wheel arg func\n"); 845 846 /* 847 * Don't lock the callwheel; all the other CPUs are paused 848 * anyhow, and we might be called in a circumstance where 849 * some other CPU was paused while holding the lock. 850 */ 851 for (ci = db_cpu_first(); ci != NULL; ci = db_cpu_next(ci)) { 852 db_read_bytes((db_addr_t)ci, sizeof(cib), (char *)&cib); 853 cc = cib.ci_data.cpu_callout; 854 db_read_bytes((db_addr_t)cc, sizeof(ccb), (char *)&ccb); 855 db_show_callout_bucket(&ccb, &cc->cc_todo, &ccb.cc_todo); 856 } 857 for (b = 0; b < BUCKETS; b++) { 858 for (ci = db_cpu_first(); ci != NULL; ci = db_cpu_next(ci)) { 859 db_read_bytes((db_addr_t)ci, sizeof(cib), (char *)&cib); 860 cc = cib.ci_data.cpu_callout; 861 db_read_bytes((db_addr_t)cc, sizeof(ccb), (char *)&ccb); 862 db_show_callout_bucket(&ccb, &cc->cc_wheel[b], 863 &ccb.cc_wheel[b]); 864 } 865 } 866 } 867 #endif /* DDB */ 868