1 /* $OpenBSD: kern_timeout.c,v 1.96 2023/10/12 15:32:38 cheloha Exp $ */ 2 /* 3 * Copyright (c) 2001 Thomas Nordin <nordin@openbsd.org> 4 * Copyright (c) 2000-2001 Artur Grabowski <art@openbsd.org> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 17 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 18 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 19 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include <sys/param.h> 29 #include <sys/systm.h> 30 #include <sys/kthread.h> 31 #include <sys/proc.h> 32 #include <sys/timeout.h> 33 #include <sys/mutex.h> 34 #include <sys/kernel.h> 35 #include <sys/queue.h> /* _Q_INVALIDATE */ 36 #include <sys/sysctl.h> 37 #include <sys/witness.h> 38 39 #ifdef DDB 40 #include <machine/db_machdep.h> 41 #include <ddb/db_interface.h> 42 #include <ddb/db_sym.h> 43 #include <ddb/db_output.h> 44 #endif 45 46 #include "kcov.h" 47 #if NKCOV > 0 48 #include <sys/kcov.h> 49 #endif 50 51 /* 52 * Locks used to protect global variables in this file: 53 * 54 * I immutable after initialization 55 * T timeout_mutex 56 */ 57 struct mutex timeout_mutex = MUTEX_INITIALIZER(IPL_HIGH); 58 59 void *softclock_si; /* [I] softclock() interrupt handle */ 60 struct timeoutstat tostat; /* [T] statistics and totals */ 61 62 /* 63 * Timeouts are kept in a hierarchical timing wheel. The to_time is the value 64 * of the global variable "ticks" when the timeout should be called. There are 65 * four levels with 256 buckets each. 66 */ 67 #define WHEELCOUNT 4 68 #define WHEELSIZE 256 69 #define WHEELMASK 255 70 #define WHEELBITS 8 71 #define BUCKETS (WHEELCOUNT * WHEELSIZE) 72 73 struct circq timeout_wheel[BUCKETS]; /* [T] Tick-based timeouts */ 74 struct circq timeout_wheel_kc[BUCKETS]; /* [T] Clock-based timeouts */ 75 struct circq timeout_new; /* [T] New, unscheduled timeouts */ 76 struct circq timeout_todo; /* [T] Due or needs rescheduling */ 77 struct circq timeout_proc; /* [T] Due + needs process context */ 78 #ifdef MULTIPROCESSOR 79 struct circq timeout_proc_mp; /* [T] Process ctx + no kernel lock */ 80 #endif 81 82 time_t timeout_level_width[WHEELCOUNT]; /* [I] Wheel level width (seconds) */ 83 struct timespec tick_ts; /* [I] Length of a tick (1/hz secs) */ 84 85 struct kclock { 86 struct timespec kc_lastscan; /* [T] Clock time at last wheel scan */ 87 struct timespec kc_late; /* [T] Late if due prior */ 88 struct timespec kc_offset; /* [T] Offset from primary kclock */ 89 } timeout_kclock[KCLOCK_MAX]; 90 91 #define MASKWHEEL(wheel, time) (((time) >> ((wheel)*WHEELBITS)) & WHEELMASK) 92 93 #define BUCKET(rel, abs) \ 94 (timeout_wheel[ \ 95 ((rel) <= (1 << (2*WHEELBITS))) \ 96 ? ((rel) <= (1 << WHEELBITS)) \ 97 ? MASKWHEEL(0, (abs)) \ 98 : MASKWHEEL(1, (abs)) + WHEELSIZE \ 99 : ((rel) <= (1 << (3*WHEELBITS))) \ 100 ? MASKWHEEL(2, (abs)) + 2*WHEELSIZE \ 101 : MASKWHEEL(3, (abs)) + 3*WHEELSIZE]) 102 103 #define MOVEBUCKET(wheel, time) \ 104 CIRCQ_CONCAT(&timeout_todo, \ 105 &timeout_wheel[MASKWHEEL((wheel), (time)) + (wheel)*WHEELSIZE]) 106 107 /* 108 * Circular queue definitions. 109 */ 110 111 #define CIRCQ_INIT(elem) do { \ 112 (elem)->next = (elem); \ 113 (elem)->prev = (elem); \ 114 } while (0) 115 116 #define CIRCQ_INSERT_TAIL(list, elem) do { \ 117 (elem)->prev = (list)->prev; \ 118 (elem)->next = (list); \ 119 (list)->prev->next = (elem); \ 120 (list)->prev = (elem); \ 121 tostat.tos_pending++; \ 122 } while (0) 123 124 #define CIRCQ_CONCAT(fst, snd) do { \ 125 if (!CIRCQ_EMPTY(snd)) { \ 126 (fst)->prev->next = (snd)->next;\ 127 (snd)->next->prev = (fst)->prev;\ 128 (snd)->prev->next = (fst); \ 129 (fst)->prev = (snd)->prev; \ 130 CIRCQ_INIT(snd); \ 131 } \ 132 } while (0) 133 134 #define CIRCQ_REMOVE(elem) do { \ 135 (elem)->next->prev = (elem)->prev; \ 136 (elem)->prev->next = (elem)->next; \ 137 _Q_INVALIDATE((elem)->prev); \ 138 _Q_INVALIDATE((elem)->next); \ 139 tostat.tos_pending--; \ 140 } while (0) 141 142 #define CIRCQ_FIRST(elem) ((elem)->next) 143 144 #define CIRCQ_EMPTY(elem) (CIRCQ_FIRST(elem) == (elem)) 145 146 #define CIRCQ_FOREACH(elem, list) \ 147 for ((elem) = CIRCQ_FIRST(list); \ 148 (elem) != (list); \ 149 (elem) = CIRCQ_FIRST(elem)) 150 151 #ifdef WITNESS 152 struct lock_object timeout_sleeplock_obj = { 153 .lo_name = "timeout", 154 .lo_flags = LO_WITNESS | LO_INITIALIZED | LO_SLEEPABLE | 155 (LO_CLASS_RWLOCK << LO_CLASSSHIFT) 156 }; 157 struct lock_object timeout_spinlock_obj = { 158 .lo_name = "timeout", 159 .lo_flags = LO_WITNESS | LO_INITIALIZED | 160 (LO_CLASS_MUTEX << LO_CLASSSHIFT) 161 }; 162 struct lock_type timeout_sleeplock_type = { 163 .lt_name = "timeout" 164 }; 165 struct lock_type timeout_spinlock_type = { 166 .lt_name = "timeout" 167 }; 168 #define TIMEOUT_LOCK_OBJ(needsproc) \ 169 ((needsproc) ? &timeout_sleeplock_obj : &timeout_spinlock_obj) 170 #endif 171 172 void softclock(void *); 173 void softclock_create_thread(void *); 174 void softclock_process_kclock_timeout(struct timeout *, int); 175 void softclock_process_tick_timeout(struct timeout *, int); 176 void softclock_thread(void *); 177 #ifdef MULTIPROCESSOR 178 void softclock_thread_mp(void *); 179 #endif 180 void timeout_barrier_timeout(void *); 181 uint32_t timeout_bucket(const struct timeout *); 182 uint32_t timeout_maskwheel(uint32_t, const struct timespec *); 183 void timeout_run(struct timeout *); 184 185 /* 186 * The first thing in a struct timeout is its struct circq, so we 187 * can get back from a pointer to the latter to a pointer to the 188 * whole timeout with just a cast. 189 */ 190 static inline struct timeout * 191 timeout_from_circq(struct circq *p) 192 { 193 return ((struct timeout *)(p)); 194 } 195 196 static inline void 197 timeout_sync_order(int needsproc) 198 { 199 WITNESS_CHECKORDER(TIMEOUT_LOCK_OBJ(needsproc), LOP_NEWORDER, NULL); 200 } 201 202 static inline void 203 timeout_sync_enter(int needsproc) 204 { 205 timeout_sync_order(needsproc); 206 WITNESS_LOCK(TIMEOUT_LOCK_OBJ(needsproc), 0); 207 } 208 209 static inline void 210 timeout_sync_leave(int needsproc) 211 { 212 WITNESS_UNLOCK(TIMEOUT_LOCK_OBJ(needsproc), 0); 213 } 214 215 /* 216 * Some of the "math" in here is a bit tricky. 217 * 218 * We have to beware of wrapping ints. 219 * We use the fact that any element added to the queue must be added with a 220 * positive time. That means that any element `to' on the queue cannot be 221 * scheduled to timeout further in time than INT_MAX, but to->to_time can 222 * be positive or negative so comparing it with anything is dangerous. 223 * The only way we can use the to->to_time value in any predictable way 224 * is when we calculate how far in the future `to' will timeout - 225 * "to->to_time - ticks". The result will always be positive for future 226 * timeouts and 0 or negative for due timeouts. 227 */ 228 229 void 230 timeout_startup(void) 231 { 232 int b, level; 233 234 CIRCQ_INIT(&timeout_new); 235 CIRCQ_INIT(&timeout_todo); 236 CIRCQ_INIT(&timeout_proc); 237 #ifdef MULTIPROCESSOR 238 CIRCQ_INIT(&timeout_proc_mp); 239 #endif 240 for (b = 0; b < nitems(timeout_wheel); b++) 241 CIRCQ_INIT(&timeout_wheel[b]); 242 for (b = 0; b < nitems(timeout_wheel_kc); b++) 243 CIRCQ_INIT(&timeout_wheel_kc[b]); 244 245 for (level = 0; level < nitems(timeout_level_width); level++) 246 timeout_level_width[level] = 2 << (level * WHEELBITS); 247 NSEC_TO_TIMESPEC(tick_nsec, &tick_ts); 248 } 249 250 void 251 timeout_proc_init(void) 252 { 253 softclock_si = softintr_establish(IPL_SOFTCLOCK, softclock, NULL); 254 if (softclock_si == NULL) 255 panic("%s: unable to register softclock interrupt", __func__); 256 257 WITNESS_INIT(&timeout_sleeplock_obj, &timeout_sleeplock_type); 258 WITNESS_INIT(&timeout_spinlock_obj, &timeout_spinlock_type); 259 260 kthread_create_deferred(softclock_create_thread, NULL); 261 } 262 263 void 264 timeout_set(struct timeout *new, void (*fn)(void *), void *arg) 265 { 266 timeout_set_flags(new, fn, arg, KCLOCK_NONE, 0); 267 } 268 269 void 270 timeout_set_flags(struct timeout *to, void (*fn)(void *), void *arg, int kclock, 271 int flags) 272 { 273 KASSERT(!ISSET(flags, ~(TIMEOUT_PROC | TIMEOUT_MPSAFE))); 274 275 to->to_func = fn; 276 to->to_arg = arg; 277 to->to_kclock = kclock; 278 to->to_flags = flags | TIMEOUT_INITIALIZED; 279 280 /* For now, only process context timeouts may be marked MP-safe. */ 281 if (ISSET(to->to_flags, TIMEOUT_MPSAFE)) 282 KASSERT(ISSET(to->to_flags, TIMEOUT_PROC)); 283 } 284 285 void 286 timeout_set_proc(struct timeout *new, void (*fn)(void *), void *arg) 287 { 288 timeout_set_flags(new, fn, arg, KCLOCK_NONE, TIMEOUT_PROC); 289 } 290 291 int 292 timeout_add(struct timeout *new, int to_ticks) 293 { 294 int old_time; 295 int ret = 1; 296 297 KASSERT(ISSET(new->to_flags, TIMEOUT_INITIALIZED)); 298 KASSERT(new->to_kclock == KCLOCK_NONE); 299 KASSERT(to_ticks >= 0); 300 301 mtx_enter(&timeout_mutex); 302 303 /* Initialize the time here, it won't change. */ 304 old_time = new->to_time; 305 new->to_time = to_ticks + ticks; 306 CLR(new->to_flags, TIMEOUT_TRIGGERED); 307 308 /* 309 * If this timeout already is scheduled and now is moved 310 * earlier, reschedule it now. Otherwise leave it in place 311 * and let it be rescheduled later. 312 */ 313 if (ISSET(new->to_flags, TIMEOUT_ONQUEUE)) { 314 if (new->to_time - ticks < old_time - ticks) { 315 CIRCQ_REMOVE(&new->to_list); 316 CIRCQ_INSERT_TAIL(&timeout_new, &new->to_list); 317 } 318 tostat.tos_readded++; 319 ret = 0; 320 } else { 321 SET(new->to_flags, TIMEOUT_ONQUEUE); 322 CIRCQ_INSERT_TAIL(&timeout_new, &new->to_list); 323 } 324 #if NKCOV > 0 325 if (!kcov_cold) 326 new->to_process = curproc->p_p; 327 #endif 328 tostat.tos_added++; 329 mtx_leave(&timeout_mutex); 330 331 return ret; 332 } 333 334 int 335 timeout_add_tv(struct timeout *to, const struct timeval *tv) 336 { 337 uint64_t to_ticks; 338 339 to_ticks = (uint64_t)hz * tv->tv_sec + tv->tv_usec / tick; 340 if (to_ticks > INT_MAX) 341 to_ticks = INT_MAX; 342 if (to_ticks == 0 && tv->tv_usec > 0) 343 to_ticks = 1; 344 345 return timeout_add(to, (int)to_ticks); 346 } 347 348 int 349 timeout_add_sec(struct timeout *to, int secs) 350 { 351 uint64_t to_ticks; 352 353 to_ticks = (uint64_t)hz * secs; 354 if (to_ticks > INT_MAX) 355 to_ticks = INT_MAX; 356 if (to_ticks == 0) 357 to_ticks = 1; 358 359 return timeout_add(to, (int)to_ticks); 360 } 361 362 int 363 timeout_add_msec(struct timeout *to, int msecs) 364 { 365 uint64_t to_ticks; 366 367 to_ticks = (uint64_t)msecs * 1000 / tick; 368 if (to_ticks > INT_MAX) 369 to_ticks = INT_MAX; 370 if (to_ticks == 0 && msecs > 0) 371 to_ticks = 1; 372 373 return timeout_add(to, (int)to_ticks); 374 } 375 376 int 377 timeout_add_usec(struct timeout *to, int usecs) 378 { 379 int to_ticks = usecs / tick; 380 381 if (to_ticks == 0 && usecs > 0) 382 to_ticks = 1; 383 384 return timeout_add(to, to_ticks); 385 } 386 387 int 388 timeout_add_nsec(struct timeout *to, int nsecs) 389 { 390 int to_ticks = nsecs / (tick * 1000); 391 392 if (to_ticks == 0 && nsecs > 0) 393 to_ticks = 1; 394 395 return timeout_add(to, to_ticks); 396 } 397 398 int 399 timeout_abs_ts(struct timeout *to, const struct timespec *abstime) 400 { 401 struct timespec old_abstime; 402 int ret = 1; 403 404 mtx_enter(&timeout_mutex); 405 406 KASSERT(ISSET(to->to_flags, TIMEOUT_INITIALIZED)); 407 KASSERT(to->to_kclock != KCLOCK_NONE); 408 409 old_abstime = to->to_abstime; 410 to->to_abstime = *abstime; 411 CLR(to->to_flags, TIMEOUT_TRIGGERED); 412 413 if (ISSET(to->to_flags, TIMEOUT_ONQUEUE)) { 414 if (timespeccmp(abstime, &old_abstime, <)) { 415 CIRCQ_REMOVE(&to->to_list); 416 CIRCQ_INSERT_TAIL(&timeout_new, &to->to_list); 417 } 418 tostat.tos_readded++; 419 ret = 0; 420 } else { 421 SET(to->to_flags, TIMEOUT_ONQUEUE); 422 CIRCQ_INSERT_TAIL(&timeout_new, &to->to_list); 423 } 424 #if NKCOV > 0 425 if (!kcov_cold) 426 to->to_process = curproc->p_p; 427 #endif 428 tostat.tos_added++; 429 430 mtx_leave(&timeout_mutex); 431 432 return ret; 433 } 434 435 int 436 timeout_del(struct timeout *to) 437 { 438 int ret = 0; 439 440 mtx_enter(&timeout_mutex); 441 if (ISSET(to->to_flags, TIMEOUT_ONQUEUE)) { 442 CIRCQ_REMOVE(&to->to_list); 443 CLR(to->to_flags, TIMEOUT_ONQUEUE); 444 tostat.tos_cancelled++; 445 ret = 1; 446 } 447 CLR(to->to_flags, TIMEOUT_TRIGGERED); 448 tostat.tos_deleted++; 449 mtx_leave(&timeout_mutex); 450 451 return ret; 452 } 453 454 int 455 timeout_del_barrier(struct timeout *to) 456 { 457 int removed; 458 459 timeout_sync_order(ISSET(to->to_flags, TIMEOUT_PROC)); 460 461 removed = timeout_del(to); 462 if (!removed) 463 timeout_barrier(to); 464 465 return removed; 466 } 467 468 void 469 timeout_barrier(struct timeout *to) 470 { 471 struct timeout barrier; 472 struct cond c; 473 int flags; 474 475 flags = to->to_flags & (TIMEOUT_PROC | TIMEOUT_MPSAFE); 476 timeout_sync_order(ISSET(flags, TIMEOUT_PROC)); 477 478 timeout_set_flags(&barrier, timeout_barrier_timeout, &c, KCLOCK_NONE, 479 flags); 480 barrier.to_process = curproc->p_p; 481 cond_init(&c); 482 483 mtx_enter(&timeout_mutex); 484 485 barrier.to_time = ticks; 486 SET(barrier.to_flags, TIMEOUT_ONQUEUE); 487 if (ISSET(flags, TIMEOUT_PROC)) { 488 #ifdef MULTIPROCESSOR 489 if (ISSET(flags, TIMEOUT_MPSAFE)) 490 CIRCQ_INSERT_TAIL(&timeout_proc_mp, &barrier.to_list); 491 else 492 #endif 493 CIRCQ_INSERT_TAIL(&timeout_proc, &barrier.to_list); 494 } else 495 CIRCQ_INSERT_TAIL(&timeout_todo, &barrier.to_list); 496 497 mtx_leave(&timeout_mutex); 498 499 if (ISSET(flags, TIMEOUT_PROC)) { 500 #ifdef MULTIPROCESSOR 501 if (ISSET(flags, TIMEOUT_MPSAFE)) 502 wakeup_one(&timeout_proc_mp); 503 else 504 #endif 505 wakeup_one(&timeout_proc); 506 } else 507 softintr_schedule(softclock_si); 508 509 cond_wait(&c, "tmobar"); 510 } 511 512 void 513 timeout_barrier_timeout(void *arg) 514 { 515 struct cond *c = arg; 516 517 cond_signal(c); 518 } 519 520 uint32_t 521 timeout_bucket(const struct timeout *to) 522 { 523 struct timespec diff, shifted_abstime; 524 struct kclock *kc; 525 uint32_t level; 526 527 KASSERT(to->to_kclock == KCLOCK_UPTIME); 528 kc = &timeout_kclock[to->to_kclock]; 529 530 KASSERT(timespeccmp(&kc->kc_lastscan, &to->to_abstime, <)); 531 timespecsub(&to->to_abstime, &kc->kc_lastscan, &diff); 532 for (level = 0; level < nitems(timeout_level_width) - 1; level++) { 533 if (diff.tv_sec < timeout_level_width[level]) 534 break; 535 } 536 timespecadd(&to->to_abstime, &kc->kc_offset, &shifted_abstime); 537 return level * WHEELSIZE + timeout_maskwheel(level, &shifted_abstime); 538 } 539 540 /* 541 * Hash the absolute time into a bucket on a given level of the wheel. 542 * 543 * The complete hash is 32 bits. The upper 25 bits are seconds, the 544 * lower 7 bits are nanoseconds. tv_nsec is a positive value less 545 * than one billion so we need to divide it to isolate the desired 546 * bits. We can't just shift it. 547 * 548 * The level is used to isolate an 8-bit portion of the hash. The 549 * resulting number indicates which bucket the absolute time belongs 550 * in on the given level of the wheel. 551 */ 552 uint32_t 553 timeout_maskwheel(uint32_t level, const struct timespec *abstime) 554 { 555 uint32_t hi, lo; 556 557 hi = abstime->tv_sec << 7; 558 lo = abstime->tv_nsec / 7812500; 559 560 return ((hi | lo) >> (level * WHEELBITS)) & WHEELMASK; 561 } 562 563 /* 564 * This is called from hardclock() on the primary CPU at the start of 565 * every tick. 566 */ 567 void 568 timeout_hardclock_update(void) 569 { 570 struct timespec elapsed, now; 571 struct kclock *kc; 572 struct timespec *lastscan = &timeout_kclock[KCLOCK_UPTIME].kc_lastscan; 573 int b, done, first, i, last, level, need_softclock = 1, off; 574 575 mtx_enter(&timeout_mutex); 576 577 MOVEBUCKET(0, ticks); 578 if (MASKWHEEL(0, ticks) == 0) { 579 MOVEBUCKET(1, ticks); 580 if (MASKWHEEL(1, ticks) == 0) { 581 MOVEBUCKET(2, ticks); 582 if (MASKWHEEL(2, ticks) == 0) 583 MOVEBUCKET(3, ticks); 584 } 585 } 586 587 /* 588 * Dump the buckets that expired while we were away. 589 * 590 * If the elapsed time has exceeded a level's limit then we need 591 * to dump every bucket in the level. We have necessarily completed 592 * a lap of that level, too, so we need to process buckets in the 593 * next level. 594 * 595 * Otherwise we need to compare indices: if the index of the first 596 * expired bucket is greater than that of the last then we have 597 * completed a lap of the level and need to process buckets in the 598 * next level. 599 */ 600 nanouptime(&now); 601 timespecsub(&now, lastscan, &elapsed); 602 for (level = 0; level < nitems(timeout_level_width); level++) { 603 first = timeout_maskwheel(level, lastscan); 604 if (elapsed.tv_sec >= timeout_level_width[level]) { 605 last = (first == 0) ? WHEELSIZE - 1 : first - 1; 606 done = 0; 607 } else { 608 last = timeout_maskwheel(level, &now); 609 done = first <= last; 610 } 611 off = level * WHEELSIZE; 612 for (b = first;; b = (b + 1) % WHEELSIZE) { 613 CIRCQ_CONCAT(&timeout_todo, &timeout_wheel_kc[off + b]); 614 if (b == last) 615 break; 616 } 617 if (done) 618 break; 619 } 620 621 /* 622 * Update the cached state for each kclock. 623 */ 624 for (i = 0; i < nitems(timeout_kclock); i++) { 625 kc = &timeout_kclock[i]; 626 timespecadd(&now, &kc->kc_offset, &kc->kc_lastscan); 627 timespecsub(&kc->kc_lastscan, &tick_ts, &kc->kc_late); 628 } 629 630 if (CIRCQ_EMPTY(&timeout_new) && CIRCQ_EMPTY(&timeout_todo)) 631 need_softclock = 0; 632 633 mtx_leave(&timeout_mutex); 634 635 if (need_softclock) 636 softintr_schedule(softclock_si); 637 } 638 639 void 640 timeout_run(struct timeout *to) 641 { 642 void (*fn)(void *); 643 void *arg; 644 int needsproc; 645 646 MUTEX_ASSERT_LOCKED(&timeout_mutex); 647 648 CLR(to->to_flags, TIMEOUT_ONQUEUE); 649 SET(to->to_flags, TIMEOUT_TRIGGERED); 650 651 fn = to->to_func; 652 arg = to->to_arg; 653 needsproc = ISSET(to->to_flags, TIMEOUT_PROC); 654 #if NKCOV > 0 655 struct process *kcov_process = to->to_process; 656 #endif 657 658 mtx_leave(&timeout_mutex); 659 timeout_sync_enter(needsproc); 660 #if NKCOV > 0 661 kcov_remote_enter(KCOV_REMOTE_COMMON, kcov_process); 662 #endif 663 fn(arg); 664 #if NKCOV > 0 665 kcov_remote_leave(KCOV_REMOTE_COMMON, kcov_process); 666 #endif 667 timeout_sync_leave(needsproc); 668 mtx_enter(&timeout_mutex); 669 } 670 671 void 672 softclock_process_kclock_timeout(struct timeout *to, int new) 673 { 674 struct kclock *kc = &timeout_kclock[to->to_kclock]; 675 676 if (timespeccmp(&to->to_abstime, &kc->kc_lastscan, >)) { 677 tostat.tos_scheduled++; 678 if (!new) 679 tostat.tos_rescheduled++; 680 CIRCQ_INSERT_TAIL(&timeout_wheel_kc[timeout_bucket(to)], 681 &to->to_list); 682 return; 683 } 684 if (!new && timespeccmp(&to->to_abstime, &kc->kc_late, <=)) 685 tostat.tos_late++; 686 if (ISSET(to->to_flags, TIMEOUT_PROC)) { 687 #ifdef MULTIPROCESSOR 688 if (ISSET(to->to_flags, TIMEOUT_MPSAFE)) 689 CIRCQ_INSERT_TAIL(&timeout_proc_mp, &to->to_list); 690 else 691 #endif 692 CIRCQ_INSERT_TAIL(&timeout_proc, &to->to_list); 693 return; 694 } 695 timeout_run(to); 696 tostat.tos_run_softclock++; 697 } 698 699 void 700 softclock_process_tick_timeout(struct timeout *to, int new) 701 { 702 int delta = to->to_time - ticks; 703 704 if (delta > 0) { 705 tostat.tos_scheduled++; 706 if (!new) 707 tostat.tos_rescheduled++; 708 CIRCQ_INSERT_TAIL(&BUCKET(delta, to->to_time), &to->to_list); 709 return; 710 } 711 if (!new && delta < 0) 712 tostat.tos_late++; 713 if (ISSET(to->to_flags, TIMEOUT_PROC)) { 714 #ifdef MULTIPROCESSOR 715 if (ISSET(to->to_flags, TIMEOUT_MPSAFE)) 716 CIRCQ_INSERT_TAIL(&timeout_proc_mp, &to->to_list); 717 else 718 #endif 719 CIRCQ_INSERT_TAIL(&timeout_proc, &to->to_list); 720 return; 721 } 722 timeout_run(to); 723 tostat.tos_run_softclock++; 724 } 725 726 /* 727 * Timeouts are processed here instead of timeout_hardclock_update() 728 * to avoid doing any more work at IPL_CLOCK than absolutely necessary. 729 * Down here at IPL_SOFTCLOCK other interrupts can be serviced promptly 730 * so the system remains responsive even if there is a surge of timeouts. 731 */ 732 void 733 softclock(void *arg) 734 { 735 struct timeout *first_new, *to; 736 int needsproc, new; 737 #ifdef MULTIPROCESSOR 738 int need_proc_mp; 739 #endif 740 741 first_new = NULL; 742 new = 0; 743 744 mtx_enter(&timeout_mutex); 745 if (!CIRCQ_EMPTY(&timeout_new)) 746 first_new = timeout_from_circq(CIRCQ_FIRST(&timeout_new)); 747 CIRCQ_CONCAT(&timeout_todo, &timeout_new); 748 while (!CIRCQ_EMPTY(&timeout_todo)) { 749 to = timeout_from_circq(CIRCQ_FIRST(&timeout_todo)); 750 CIRCQ_REMOVE(&to->to_list); 751 if (to == first_new) 752 new = 1; 753 if (to->to_kclock != KCLOCK_NONE) 754 softclock_process_kclock_timeout(to, new); 755 else 756 softclock_process_tick_timeout(to, new); 757 } 758 tostat.tos_softclocks++; 759 needsproc = !CIRCQ_EMPTY(&timeout_proc); 760 #ifdef MULTIPROCESSOR 761 need_proc_mp = !CIRCQ_EMPTY(&timeout_proc_mp); 762 #endif 763 mtx_leave(&timeout_mutex); 764 765 if (needsproc) 766 wakeup(&timeout_proc); 767 #ifdef MULTIPROCESSOR 768 if (need_proc_mp) 769 wakeup(&timeout_proc_mp); 770 #endif 771 } 772 773 void 774 softclock_create_thread(void *arg) 775 { 776 if (kthread_create(softclock_thread, NULL, NULL, "softclock")) 777 panic("fork softclock"); 778 #ifdef MULTIPROCESSOR 779 if (kthread_create(softclock_thread_mp, NULL, NULL, "softclockmp")) 780 panic("kthread_create softclock_thread_mp"); 781 #endif 782 } 783 784 void 785 softclock_thread(void *arg) 786 { 787 CPU_INFO_ITERATOR cii; 788 struct cpu_info *ci; 789 struct timeout *to; 790 int s; 791 792 KERNEL_ASSERT_LOCKED(); 793 794 /* Be conservative for the moment */ 795 CPU_INFO_FOREACH(cii, ci) { 796 if (CPU_IS_PRIMARY(ci)) 797 break; 798 } 799 KASSERT(ci != NULL); 800 sched_peg_curproc(ci); 801 802 s = splsoftclock(); 803 mtx_enter(&timeout_mutex); 804 for (;;) { 805 while (!CIRCQ_EMPTY(&timeout_proc)) { 806 to = timeout_from_circq(CIRCQ_FIRST(&timeout_proc)); 807 CIRCQ_REMOVE(&to->to_list); 808 timeout_run(to); 809 tostat.tos_run_thread++; 810 } 811 tostat.tos_thread_wakeups++; 812 msleep_nsec(&timeout_proc, &timeout_mutex, PSWP, "tmoslp", 813 INFSLP); 814 } 815 splx(s); 816 } 817 818 #ifdef MULTIPROCESSOR 819 void 820 softclock_thread_mp(void *arg) 821 { 822 struct timeout *to; 823 824 KERNEL_ASSERT_LOCKED(); 825 KERNEL_UNLOCK(); 826 827 mtx_enter(&timeout_mutex); 828 for (;;) { 829 while (!CIRCQ_EMPTY(&timeout_proc_mp)) { 830 to = timeout_from_circq(CIRCQ_FIRST(&timeout_proc_mp)); 831 CIRCQ_REMOVE(&to->to_list); 832 timeout_run(to); 833 tostat.tos_run_thread++; 834 } 835 tostat.tos_thread_wakeups++; 836 msleep_nsec(&timeout_proc_mp, &timeout_mutex, PSWP, "tmoslp", 837 INFSLP); 838 } 839 } 840 #endif /* MULTIPROCESSOR */ 841 842 #ifndef SMALL_KERNEL 843 void 844 timeout_adjust_ticks(int adj) 845 { 846 struct timeout *to; 847 struct circq *p; 848 int new_ticks, b; 849 850 /* adjusting the monotonic clock backwards would be a Bad Thing */ 851 if (adj <= 0) 852 return; 853 854 mtx_enter(&timeout_mutex); 855 new_ticks = ticks + adj; 856 for (b = 0; b < nitems(timeout_wheel); b++) { 857 p = CIRCQ_FIRST(&timeout_wheel[b]); 858 while (p != &timeout_wheel[b]) { 859 to = timeout_from_circq(p); 860 p = CIRCQ_FIRST(p); 861 862 /* when moving a timeout forward need to reinsert it */ 863 if (to->to_time - ticks < adj) 864 to->to_time = new_ticks; 865 CIRCQ_REMOVE(&to->to_list); 866 CIRCQ_INSERT_TAIL(&timeout_todo, &to->to_list); 867 } 868 } 869 ticks = new_ticks; 870 mtx_leave(&timeout_mutex); 871 } 872 #endif 873 874 int 875 timeout_sysctl(void *oldp, size_t *oldlenp, void *newp, size_t newlen) 876 { 877 struct timeoutstat status; 878 879 mtx_enter(&timeout_mutex); 880 memcpy(&status, &tostat, sizeof(status)); 881 mtx_leave(&timeout_mutex); 882 883 return sysctl_rdstruct(oldp, oldlenp, newp, &status, sizeof(status)); 884 } 885 886 #ifdef DDB 887 const char *db_kclock(int); 888 void db_show_callout_bucket(struct circq *); 889 void db_show_timeout(struct timeout *, struct circq *); 890 const char *db_timespec(const struct timespec *); 891 892 const char * 893 db_kclock(int kclock) 894 { 895 switch (kclock) { 896 case KCLOCK_UPTIME: 897 return "uptime"; 898 default: 899 return "invalid"; 900 } 901 } 902 903 const char * 904 db_timespec(const struct timespec *ts) 905 { 906 static char buf[32]; 907 struct timespec tmp, zero; 908 909 if (ts->tv_sec >= 0) { 910 snprintf(buf, sizeof(buf), "%lld.%09ld", 911 ts->tv_sec, ts->tv_nsec); 912 return buf; 913 } 914 915 timespecclear(&zero); 916 timespecsub(&zero, ts, &tmp); 917 snprintf(buf, sizeof(buf), "-%lld.%09ld", tmp.tv_sec, tmp.tv_nsec); 918 return buf; 919 } 920 921 void 922 db_show_callout_bucket(struct circq *bucket) 923 { 924 struct circq *p; 925 926 CIRCQ_FOREACH(p, bucket) 927 db_show_timeout(timeout_from_circq(p), bucket); 928 } 929 930 void 931 db_show_timeout(struct timeout *to, struct circq *bucket) 932 { 933 struct timespec remaining; 934 struct kclock *kc; 935 char buf[8]; 936 db_expr_t offset; 937 struct circq *wheel; 938 char *name, *where; 939 int width = sizeof(long) * 2; 940 941 db_find_sym_and_offset((vaddr_t)to->to_func, &name, &offset); 942 name = name ? name : "?"; 943 if (bucket == &timeout_new) 944 where = "new"; 945 else if (bucket == &timeout_todo) 946 where = "softint"; 947 else if (bucket == &timeout_proc) 948 where = "thread"; 949 #ifdef MULTIPROCESSOR 950 else if (bucket == &timeout_proc_mp) 951 where = "thread-mp"; 952 #endif 953 else { 954 if (to->to_kclock != KCLOCK_NONE) 955 wheel = timeout_wheel_kc; 956 else 957 wheel = timeout_wheel; 958 snprintf(buf, sizeof(buf), "%3ld/%1ld", 959 (bucket - wheel) % WHEELSIZE, 960 (bucket - wheel) / WHEELSIZE); 961 where = buf; 962 } 963 if (to->to_kclock != KCLOCK_NONE) { 964 kc = &timeout_kclock[to->to_kclock]; 965 timespecsub(&to->to_abstime, &kc->kc_lastscan, &remaining); 966 db_printf("%20s %8s %9s 0x%0*lx %s\n", 967 db_timespec(&remaining), db_kclock(to->to_kclock), where, 968 width, (ulong)to->to_arg, name); 969 } else { 970 db_printf("%20d %8s %9s 0x%0*lx %s\n", 971 to->to_time - ticks, "ticks", where, 972 width, (ulong)to->to_arg, name); 973 } 974 } 975 976 void 977 db_show_callout(db_expr_t addr, int haddr, db_expr_t count, char *modif) 978 { 979 struct kclock *kc; 980 int width = sizeof(long) * 2 + 2; 981 int b, i; 982 983 db_printf("%20s %8s\n", "lastscan", "clock"); 984 db_printf("%20d %8s\n", ticks, "ticks"); 985 for (i = 0; i < nitems(timeout_kclock); i++) { 986 kc = &timeout_kclock[i]; 987 db_printf("%20s %8s\n", 988 db_timespec(&kc->kc_lastscan), db_kclock(i)); 989 } 990 db_printf("\n"); 991 db_printf("%20s %8s %9s %*s %s\n", 992 "remaining", "clock", "wheel", width, "arg", "func"); 993 db_show_callout_bucket(&timeout_new); 994 db_show_callout_bucket(&timeout_todo); 995 db_show_callout_bucket(&timeout_proc); 996 #ifdef MULTIPROCESSOR 997 db_show_callout_bucket(&timeout_proc_mp); 998 #endif 999 for (b = 0; b < nitems(timeout_wheel); b++) 1000 db_show_callout_bucket(&timeout_wheel[b]); 1001 for (b = 0; b < nitems(timeout_wheel_kc); b++) 1002 db_show_callout_bucket(&timeout_wheel_kc[b]); 1003 } 1004 #endif 1005