kern_timeout.c revision 302237
1/*- 2 * Copyright (c) 1982, 1986, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 35 */ 36 37#include <sys/cdefs.h> 38__FBSDID("$FreeBSD: stable/10/sys/kern/kern_timeout.c 302237 2016-06-27 22:10:07Z bdrewery $"); 39 40#include "opt_callout_profiling.h" 41#include "opt_kdtrace.h" 42#if defined(__arm__) 43#include "opt_timer.h" 44#endif 45 46#include <sys/param.h> 47#include <sys/systm.h> 48#include <sys/bus.h> 49#include <sys/callout.h> 50#include <sys/file.h> 51#include <sys/interrupt.h> 52#include <sys/kernel.h> 53#include <sys/ktr.h> 54#include <sys/lock.h> 55#include <sys/malloc.h> 56#include <sys/mutex.h> 57#include <sys/proc.h> 58#include <sys/sdt.h> 59#include <sys/sleepqueue.h> 60#include <sys/sysctl.h> 61#include <sys/smp.h> 62 63#ifdef SMP 64#include <machine/cpu.h> 65#endif 66 67#ifndef NO_EVENTTIMERS 68DPCPU_DECLARE(sbintime_t, hardclocktime); 69#endif 70 71SDT_PROVIDER_DEFINE(callout_execute); 72SDT_PROBE_DEFINE1(callout_execute, , , callout__start, "struct callout *"); 73SDT_PROBE_DEFINE1(callout_execute, , , callout__end, "struct callout *"); 74 75#ifdef CALLOUT_PROFILING 76static int avg_depth; 77SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, 78 "Average number of items examined per softclock call. Units = 1/1000"); 79static int avg_gcalls; 80SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, 81 "Average number of Giant callouts made per softclock call. Units = 1/1000"); 82static int avg_lockcalls; 83SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0, 84 "Average number of lock callouts made per softclock call. Units = 1/1000"); 85static int avg_mpcalls; 86SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, 87 "Average number of MP callouts made per softclock call. Units = 1/1000"); 88static int avg_depth_dir; 89SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0, 90 "Average number of direct callouts examined per callout_process call. " 91 "Units = 1/1000"); 92static int avg_lockcalls_dir; 93SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD, 94 &avg_lockcalls_dir, 0, "Average number of lock direct callouts made per " 95 "callout_process call. Units = 1/1000"); 96static int avg_mpcalls_dir; 97SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir, 98 0, "Average number of MP direct callouts made per callout_process call. " 99 "Units = 1/1000"); 100#endif 101 102static int ncallout; 103SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN, &ncallout, 0, 104 "Number of entries in callwheel and size of timeout() preallocation"); 105 106/* 107 * TODO: 108 * allocate more timeout table slots when table overflows. 109 */ 110u_int callwheelsize, callwheelmask; 111 112/* 113 * The callout cpu exec entities represent informations necessary for 114 * describing the state of callouts currently running on the CPU and the ones 115 * necessary for migrating callouts to the new callout cpu. In particular, 116 * the first entry of the array cc_exec_entity holds informations for callout 117 * running in SWI thread context, while the second one holds informations 118 * for callout running directly from hardware interrupt context. 119 * The cached informations are very important for deferring migration when 120 * the migrating callout is already running. 121 */ 122struct cc_exec { 123 struct callout *cc_curr; 124#ifdef SMP 125 void (*ce_migration_func)(void *); 126 void *ce_migration_arg; 127 int ce_migration_cpu; 128 sbintime_t ce_migration_time; 129 sbintime_t ce_migration_prec; 130#endif 131 bool cc_cancel; 132 bool cc_waiting; 133}; 134 135/* 136 * There is one struct callout_cpu per cpu, holding all relevant 137 * state for the callout processing thread on the individual CPU. 138 */ 139struct callout_cpu { 140 struct mtx_padalign cc_lock; 141 struct cc_exec cc_exec_entity[2]; 142 struct callout *cc_next; 143 struct callout *cc_callout; 144 struct callout_list *cc_callwheel; 145 struct callout_tailq cc_expireq; 146 struct callout_slist cc_callfree; 147 sbintime_t cc_firstevent; 148 sbintime_t cc_lastscan; 149 void *cc_cookie; 150 u_int cc_bucket; 151 u_int cc_inited; 152 char cc_ktr_event_name[20]; 153}; 154 155#define callout_migrating(c) ((c)->c_iflags & CALLOUT_DFRMIGRATION) 156 157#define cc_exec_curr(cc, dir) cc->cc_exec_entity[dir].cc_curr 158#define cc_exec_next(cc) cc->cc_next 159#define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel 160#define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting 161#ifdef SMP 162#define cc_migration_func(cc, dir) cc->cc_exec_entity[dir].ce_migration_func 163#define cc_migration_arg(cc, dir) cc->cc_exec_entity[dir].ce_migration_arg 164#define cc_migration_cpu(cc, dir) cc->cc_exec_entity[dir].ce_migration_cpu 165#define cc_migration_time(cc, dir) cc->cc_exec_entity[dir].ce_migration_time 166#define cc_migration_prec(cc, dir) cc->cc_exec_entity[dir].ce_migration_prec 167 168struct callout_cpu cc_cpu[MAXCPU]; 169#define CPUBLOCK MAXCPU 170#define CC_CPU(cpu) (&cc_cpu[(cpu)]) 171#define CC_SELF() CC_CPU(PCPU_GET(cpuid)) 172#else 173struct callout_cpu cc_cpu; 174#define CC_CPU(cpu) &cc_cpu 175#define CC_SELF() &cc_cpu 176#endif 177#define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) 178#define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) 179#define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) 180 181static int timeout_cpu; 182 183static void callout_cpu_init(struct callout_cpu *cc, int cpu); 184static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, 185#ifdef CALLOUT_PROFILING 186 int *mpcalls, int *lockcalls, int *gcalls, 187#endif 188 int direct); 189 190static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); 191 192/** 193 * Locked by cc_lock: 194 * cc_curr - If a callout is in progress, it is cc_curr. 195 * If cc_curr is non-NULL, threads waiting in 196 * callout_drain() will be woken up as soon as the 197 * relevant callout completes. 198 * cc_cancel - Changing to 1 with both callout_lock and cc_lock held 199 * guarantees that the current callout will not run. 200 * The softclock() function sets this to 0 before it 201 * drops callout_lock to acquire c_lock, and it calls 202 * the handler only if curr_cancelled is still 0 after 203 * cc_lock is successfully acquired. 204 * cc_waiting - If a thread is waiting in callout_drain(), then 205 * callout_wait is nonzero. Set only when 206 * cc_curr is non-NULL. 207 */ 208 209/* 210 * Resets the execution entity tied to a specific callout cpu. 211 */ 212static void 213cc_cce_cleanup(struct callout_cpu *cc, int direct) 214{ 215 216 cc_exec_curr(cc, direct) = NULL; 217 cc_exec_cancel(cc, direct) = false; 218 cc_exec_waiting(cc, direct) = false; 219#ifdef SMP 220 cc_migration_cpu(cc, direct) = CPUBLOCK; 221 cc_migration_time(cc, direct) = 0; 222 cc_migration_prec(cc, direct) = 0; 223 cc_migration_func(cc, direct) = NULL; 224 cc_migration_arg(cc, direct) = NULL; 225#endif 226} 227 228/* 229 * Checks if migration is requested by a specific callout cpu. 230 */ 231static int 232cc_cce_migrating(struct callout_cpu *cc, int direct) 233{ 234 235#ifdef SMP 236 return (cc_migration_cpu(cc, direct) != CPUBLOCK); 237#else 238 return (0); 239#endif 240} 241 242/* 243 * Kernel low level callwheel initialization 244 * called on cpu0 during kernel startup. 245 */ 246static void 247callout_callwheel_init(void *dummy) 248{ 249 struct callout_cpu *cc; 250 251 /* 252 * Calculate the size of the callout wheel and the preallocated 253 * timeout() structures. 254 * XXX: Clip callout to result of previous function of maxusers 255 * maximum 384. This is still huge, but acceptable. 256 */ 257 memset(CC_CPU(0), 0, sizeof(cc_cpu)); 258 ncallout = imin(16 + maxproc + maxfiles, 18508); 259 TUNABLE_INT_FETCH("kern.ncallout", &ncallout); 260 261 /* 262 * Calculate callout wheel size, should be next power of two higher 263 * than 'ncallout'. 264 */ 265 callwheelsize = 1 << fls(ncallout); 266 callwheelmask = callwheelsize - 1; 267 268 /* 269 * Only cpu0 handles timeout(9) and receives a preallocation. 270 * 271 * XXX: Once all timeout(9) consumers are converted this can 272 * be removed. 273 */ 274 timeout_cpu = PCPU_GET(cpuid); 275 cc = CC_CPU(timeout_cpu); 276 cc->cc_callout = malloc(ncallout * sizeof(struct callout), 277 M_CALLOUT, M_WAITOK); 278 callout_cpu_init(cc, timeout_cpu); 279} 280SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); 281 282/* 283 * Initialize the per-cpu callout structures. 284 */ 285static void 286callout_cpu_init(struct callout_cpu *cc, int cpu) 287{ 288 struct callout *c; 289 int i; 290 291 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); 292 SLIST_INIT(&cc->cc_callfree); 293 cc->cc_inited = 1; 294 cc->cc_callwheel = malloc(sizeof(struct callout_list) * callwheelsize, 295 M_CALLOUT, M_WAITOK); 296 for (i = 0; i < callwheelsize; i++) 297 LIST_INIT(&cc->cc_callwheel[i]); 298 TAILQ_INIT(&cc->cc_expireq); 299 cc->cc_firstevent = INT64_MAX; 300 for (i = 0; i < 2; i++) 301 cc_cce_cleanup(cc, i); 302 snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name), 303 "callwheel cpu %d", cpu); 304 if (cc->cc_callout == NULL) /* Only cpu0 handles timeout(9) */ 305 return; 306 for (i = 0; i < ncallout; i++) { 307 c = &cc->cc_callout[i]; 308 callout_init(c, 0); 309 c->c_iflags = CALLOUT_LOCAL_ALLOC; 310 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 311 } 312} 313 314#ifdef SMP 315/* 316 * Switches the cpu tied to a specific callout. 317 * The function expects a locked incoming callout cpu and returns with 318 * locked outcoming callout cpu. 319 */ 320static struct callout_cpu * 321callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu) 322{ 323 struct callout_cpu *new_cc; 324 325 MPASS(c != NULL && cc != NULL); 326 CC_LOCK_ASSERT(cc); 327 328 /* 329 * Avoid interrupts and preemption firing after the callout cpu 330 * is blocked in order to avoid deadlocks as the new thread 331 * may be willing to acquire the callout cpu lock. 332 */ 333 c->c_cpu = CPUBLOCK; 334 spinlock_enter(); 335 CC_UNLOCK(cc); 336 new_cc = CC_CPU(new_cpu); 337 CC_LOCK(new_cc); 338 spinlock_exit(); 339 c->c_cpu = new_cpu; 340 return (new_cc); 341} 342#endif 343 344/* 345 * Start standard softclock thread. 346 */ 347static void 348start_softclock(void *dummy) 349{ 350 struct callout_cpu *cc; 351#ifdef SMP 352 int cpu; 353#endif 354 355 cc = CC_CPU(timeout_cpu); 356 if (swi_add(&clk_intr_event, "clock", softclock, cc, SWI_CLOCK, 357 INTR_MPSAFE, &cc->cc_cookie)) 358 panic("died while creating standard software ithreads"); 359#ifdef SMP 360 CPU_FOREACH(cpu) { 361 if (cpu == timeout_cpu) 362 continue; 363 cc = CC_CPU(cpu); 364 cc->cc_callout = NULL; /* Only cpu0 handles timeout(9). */ 365 callout_cpu_init(cc, cpu); 366 if (swi_add(NULL, "clock", softclock, cc, SWI_CLOCK, 367 INTR_MPSAFE, &cc->cc_cookie)) 368 panic("died while creating standard software ithreads"); 369 } 370#endif 371} 372SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); 373 374#define CC_HASH_SHIFT 8 375 376static inline u_int 377callout_hash(sbintime_t sbt) 378{ 379 380 return (sbt >> (32 - CC_HASH_SHIFT)); 381} 382 383static inline u_int 384callout_get_bucket(sbintime_t sbt) 385{ 386 387 return (callout_hash(sbt) & callwheelmask); 388} 389 390void 391callout_process(sbintime_t now) 392{ 393 struct callout *tmp, *tmpn; 394 struct callout_cpu *cc; 395 struct callout_list *sc; 396 sbintime_t first, last, max, tmp_max; 397 uint32_t lookahead; 398 u_int firstb, lastb, nowb; 399#ifdef CALLOUT_PROFILING 400 int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0; 401#endif 402 403 cc = CC_SELF(); 404 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET); 405 406 /* Compute the buckets of the last scan and present times. */ 407 firstb = callout_hash(cc->cc_lastscan); 408 cc->cc_lastscan = now; 409 nowb = callout_hash(now); 410 411 /* Compute the last bucket and minimum time of the bucket after it. */ 412 if (nowb == firstb) 413 lookahead = (SBT_1S / 16); 414 else if (nowb - firstb == 1) 415 lookahead = (SBT_1S / 8); 416 else 417 lookahead = (SBT_1S / 2); 418 first = last = now; 419 first += (lookahead / 2); 420 last += lookahead; 421 last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); 422 lastb = callout_hash(last) - 1; 423 max = last; 424 425 /* 426 * Check if we wrapped around the entire wheel from the last scan. 427 * In case, we need to scan entirely the wheel for pending callouts. 428 */ 429 if (lastb - firstb >= callwheelsize) { 430 lastb = firstb + callwheelsize - 1; 431 if (nowb - firstb >= callwheelsize) 432 nowb = lastb; 433 } 434 435 /* Iterate callwheel from firstb to nowb and then up to lastb. */ 436 do { 437 sc = &cc->cc_callwheel[firstb & callwheelmask]; 438 tmp = LIST_FIRST(sc); 439 while (tmp != NULL) { 440 /* Run the callout if present time within allowed. */ 441 if (tmp->c_time <= now) { 442 /* 443 * Consumer told us the callout may be run 444 * directly from hardware interrupt context. 445 */ 446 if (tmp->c_iflags & CALLOUT_DIRECT) { 447#ifdef CALLOUT_PROFILING 448 ++depth_dir; 449#endif 450 cc_exec_next(cc) = 451 LIST_NEXT(tmp, c_links.le); 452 cc->cc_bucket = firstb & callwheelmask; 453 LIST_REMOVE(tmp, c_links.le); 454 softclock_call_cc(tmp, cc, 455#ifdef CALLOUT_PROFILING 456 &mpcalls_dir, &lockcalls_dir, NULL, 457#endif 458 1); 459 tmp = cc_exec_next(cc); 460 cc_exec_next(cc) = NULL; 461 } else { 462 tmpn = LIST_NEXT(tmp, c_links.le); 463 LIST_REMOVE(tmp, c_links.le); 464 TAILQ_INSERT_TAIL(&cc->cc_expireq, 465 tmp, c_links.tqe); 466 tmp->c_iflags |= CALLOUT_PROCESSED; 467 tmp = tmpn; 468 } 469 continue; 470 } 471 /* Skip events from distant future. */ 472 if (tmp->c_time >= max) 473 goto next; 474 /* 475 * Event minimal time is bigger than present maximal 476 * time, so it cannot be aggregated. 477 */ 478 if (tmp->c_time > last) { 479 lastb = nowb; 480 goto next; 481 } 482 /* Update first and last time, respecting this event. */ 483 if (tmp->c_time < first) 484 first = tmp->c_time; 485 tmp_max = tmp->c_time + tmp->c_precision; 486 if (tmp_max < last) 487 last = tmp_max; 488next: 489 tmp = LIST_NEXT(tmp, c_links.le); 490 } 491 /* Proceed with the next bucket. */ 492 firstb++; 493 /* 494 * Stop if we looked after present time and found 495 * some event we can't execute at now. 496 * Stop if we looked far enough into the future. 497 */ 498 } while (((int)(firstb - lastb)) <= 0); 499 cc->cc_firstevent = last; 500#ifndef NO_EVENTTIMERS 501 cpu_new_callout(curcpu, last, first); 502#endif 503#ifdef CALLOUT_PROFILING 504 avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8; 505 avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8; 506 avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8; 507#endif 508 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 509 /* 510 * swi_sched acquires the thread lock, so we don't want to call it 511 * with cc_lock held; incorrect locking order. 512 */ 513 if (!TAILQ_EMPTY(&cc->cc_expireq)) 514 swi_sched(cc->cc_cookie, 0); 515} 516 517static struct callout_cpu * 518callout_lock(struct callout *c) 519{ 520 struct callout_cpu *cc; 521 int cpu; 522 523 for (;;) { 524 cpu = c->c_cpu; 525#ifdef SMP 526 if (cpu == CPUBLOCK) { 527 while (c->c_cpu == CPUBLOCK) 528 cpu_spinwait(); 529 continue; 530 } 531#endif 532 cc = CC_CPU(cpu); 533 CC_LOCK(cc); 534 if (cpu == c->c_cpu) 535 break; 536 CC_UNLOCK(cc); 537 } 538 return (cc); 539} 540 541static void 542callout_cc_add(struct callout *c, struct callout_cpu *cc, 543 sbintime_t sbt, sbintime_t precision, void (*func)(void *), 544 void *arg, int cpu, int flags) 545{ 546 int bucket; 547 548 CC_LOCK_ASSERT(cc); 549 if (sbt < cc->cc_lastscan) 550 sbt = cc->cc_lastscan; 551 c->c_arg = arg; 552 c->c_iflags |= CALLOUT_PENDING; 553 c->c_iflags &= ~CALLOUT_PROCESSED; 554 c->c_flags |= CALLOUT_ACTIVE; 555 if (flags & C_DIRECT_EXEC) 556 c->c_iflags |= CALLOUT_DIRECT; 557 c->c_func = func; 558 c->c_time = sbt; 559 c->c_precision = precision; 560 bucket = callout_get_bucket(c->c_time); 561 CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x", 562 c, (int)(c->c_precision >> 32), 563 (u_int)(c->c_precision & 0xffffffff)); 564 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); 565 if (cc->cc_bucket == bucket) 566 cc_exec_next(cc) = c; 567#ifndef NO_EVENTTIMERS 568 /* 569 * Inform the eventtimers(4) subsystem there's a new callout 570 * that has been inserted, but only if really required. 571 */ 572 if (INT64_MAX - c->c_time < c->c_precision) 573 c->c_precision = INT64_MAX - c->c_time; 574 sbt = c->c_time + c->c_precision; 575 if (sbt < cc->cc_firstevent) { 576 cc->cc_firstevent = sbt; 577 cpu_new_callout(cpu, sbt, c->c_time); 578 } 579#endif 580} 581 582static void 583callout_cc_del(struct callout *c, struct callout_cpu *cc) 584{ 585 586 if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) == 0) 587 return; 588 c->c_func = NULL; 589 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 590} 591 592static void 593softclock_call_cc(struct callout *c, struct callout_cpu *cc, 594#ifdef CALLOUT_PROFILING 595 int *mpcalls, int *lockcalls, int *gcalls, 596#endif 597 int direct) 598{ 599 struct rm_priotracker tracker; 600 void (*c_func)(void *); 601 void *c_arg; 602 struct lock_class *class; 603 struct lock_object *c_lock; 604 uintptr_t lock_status; 605 int c_iflags; 606#ifdef SMP 607 struct callout_cpu *new_cc; 608 void (*new_func)(void *); 609 void *new_arg; 610 int flags, new_cpu; 611 sbintime_t new_prec, new_time; 612#endif 613#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 614 sbintime_t sbt1, sbt2; 615 struct timespec ts2; 616 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 617 static timeout_t *lastfunc; 618#endif 619 620 KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING, 621 ("softclock_call_cc: pend %p %x", c, c->c_iflags)); 622 KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE, 623 ("softclock_call_cc: act %p %x", c, c->c_flags)); 624 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; 625 lock_status = 0; 626 if (c->c_flags & CALLOUT_SHAREDLOCK) { 627 if (class == &lock_class_rm) 628 lock_status = (uintptr_t)&tracker; 629 else 630 lock_status = 1; 631 } 632 c_lock = c->c_lock; 633 c_func = c->c_func; 634 c_arg = c->c_arg; 635 c_iflags = c->c_iflags; 636 if (c->c_iflags & CALLOUT_LOCAL_ALLOC) 637 c->c_iflags = CALLOUT_LOCAL_ALLOC; 638 else 639 c->c_iflags &= ~CALLOUT_PENDING; 640 641 cc_exec_curr(cc, direct) = c; 642 cc_exec_cancel(cc, direct) = false; 643 CC_UNLOCK(cc); 644 if (c_lock != NULL) { 645 class->lc_lock(c_lock, lock_status); 646 /* 647 * The callout may have been cancelled 648 * while we switched locks. 649 */ 650 if (cc_exec_cancel(cc, direct)) { 651 class->lc_unlock(c_lock); 652 goto skip; 653 } 654 /* The callout cannot be stopped now. */ 655 cc_exec_cancel(cc, direct) = true; 656 if (c_lock == &Giant.lock_object) { 657#ifdef CALLOUT_PROFILING 658 (*gcalls)++; 659#endif 660 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", 661 c, c_func, c_arg); 662 } else { 663#ifdef CALLOUT_PROFILING 664 (*lockcalls)++; 665#endif 666 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", 667 c, c_func, c_arg); 668 } 669 } else { 670#ifdef CALLOUT_PROFILING 671 (*mpcalls)++; 672#endif 673 CTR3(KTR_CALLOUT, "callout %p func %p arg %p", 674 c, c_func, c_arg); 675 } 676 KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running", 677 "func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct); 678#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 679 sbt1 = sbinuptime(); 680#endif 681 THREAD_NO_SLEEPING(); 682 SDT_PROBE1(callout_execute, , , callout__start, c); 683 c_func(c_arg); 684 SDT_PROBE1(callout_execute, , , callout__end, c); 685 THREAD_SLEEPING_OK(); 686#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 687 sbt2 = sbinuptime(); 688 sbt2 -= sbt1; 689 if (sbt2 > maxdt) { 690 if (lastfunc != c_func || sbt2 > maxdt * 2) { 691 ts2 = sbttots(sbt2); 692 printf( 693 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 694 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); 695 } 696 maxdt = sbt2; 697 lastfunc = c_func; 698 } 699#endif 700 KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle"); 701 CTR1(KTR_CALLOUT, "callout %p finished", c); 702 if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0) 703 class->lc_unlock(c_lock); 704skip: 705 CC_LOCK(cc); 706 KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr")); 707 cc_exec_curr(cc, direct) = NULL; 708 if (cc_exec_waiting(cc, direct)) { 709 /* 710 * There is someone waiting for the 711 * callout to complete. 712 * If the callout was scheduled for 713 * migration just cancel it. 714 */ 715 if (cc_cce_migrating(cc, direct)) { 716 cc_cce_cleanup(cc, direct); 717 718 /* 719 * It should be assert here that the callout is not 720 * destroyed but that is not easy. 721 */ 722 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 723 } 724 cc_exec_waiting(cc, direct) = false; 725 CC_UNLOCK(cc); 726 wakeup(&cc_exec_waiting(cc, direct)); 727 CC_LOCK(cc); 728 } else if (cc_cce_migrating(cc, direct)) { 729 KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0, 730 ("Migrating legacy callout %p", c)); 731#ifdef SMP 732 /* 733 * If the callout was scheduled for 734 * migration just perform it now. 735 */ 736 new_cpu = cc_migration_cpu(cc, direct); 737 new_time = cc_migration_time(cc, direct); 738 new_prec = cc_migration_prec(cc, direct); 739 new_func = cc_migration_func(cc, direct); 740 new_arg = cc_migration_arg(cc, direct); 741 cc_cce_cleanup(cc, direct); 742 743 /* 744 * It should be assert here that the callout is not destroyed 745 * but that is not easy. 746 * 747 * As first thing, handle deferred callout stops. 748 */ 749 if (!callout_migrating(c)) { 750 CTR3(KTR_CALLOUT, 751 "deferred cancelled %p func %p arg %p", 752 c, new_func, new_arg); 753 callout_cc_del(c, cc); 754 return; 755 } 756 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 757 758 new_cc = callout_cpu_switch(c, cc, new_cpu); 759 flags = (direct) ? C_DIRECT_EXEC : 0; 760 callout_cc_add(c, new_cc, new_time, new_prec, new_func, 761 new_arg, new_cpu, flags); 762 CC_UNLOCK(new_cc); 763 CC_LOCK(cc); 764#else 765 panic("migration should not happen"); 766#endif 767 } 768 /* 769 * If the current callout is locally allocated (from 770 * timeout(9)) then put it on the freelist. 771 * 772 * Note: we need to check the cached copy of c_iflags because 773 * if it was not local, then it's not safe to deref the 774 * callout pointer. 775 */ 776 KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0 || 777 c->c_iflags == CALLOUT_LOCAL_ALLOC, 778 ("corrupted callout")); 779 if (c_iflags & CALLOUT_LOCAL_ALLOC) 780 callout_cc_del(c, cc); 781} 782 783/* 784 * The callout mechanism is based on the work of Adam M. Costello and 785 * George Varghese, published in a technical report entitled "Redesigning 786 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 787 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 788 * used in this implementation was published by G. Varghese and T. Lauck in 789 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 790 * the Efficient Implementation of a Timer Facility" in the Proceedings of 791 * the 11th ACM Annual Symposium on Operating Systems Principles, 792 * Austin, Texas Nov 1987. 793 */ 794 795/* 796 * Software (low priority) clock interrupt. 797 * Run periodic events from timeout queue. 798 */ 799void 800softclock(void *arg) 801{ 802 struct callout_cpu *cc; 803 struct callout *c; 804#ifdef CALLOUT_PROFILING 805 int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0; 806#endif 807 808 cc = (struct callout_cpu *)arg; 809 CC_LOCK(cc); 810 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { 811 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 812 softclock_call_cc(c, cc, 813#ifdef CALLOUT_PROFILING 814 &mpcalls, &lockcalls, &gcalls, 815#endif 816 0); 817#ifdef CALLOUT_PROFILING 818 ++depth; 819#endif 820 } 821#ifdef CALLOUT_PROFILING 822 avg_depth += (depth * 1000 - avg_depth) >> 8; 823 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 824 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 825 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 826#endif 827 CC_UNLOCK(cc); 828} 829 830/* 831 * timeout -- 832 * Execute a function after a specified length of time. 833 * 834 * untimeout -- 835 * Cancel previous timeout function call. 836 * 837 * callout_handle_init -- 838 * Initialize a handle so that using it with untimeout is benign. 839 * 840 * See AT&T BCI Driver Reference Manual for specification. This 841 * implementation differs from that one in that although an 842 * identification value is returned from timeout, the original 843 * arguments to timeout as well as the identifier are used to 844 * identify entries for untimeout. 845 */ 846struct callout_handle 847timeout(ftn, arg, to_ticks) 848 timeout_t *ftn; 849 void *arg; 850 int to_ticks; 851{ 852 struct callout_cpu *cc; 853 struct callout *new; 854 struct callout_handle handle; 855 856 cc = CC_CPU(timeout_cpu); 857 CC_LOCK(cc); 858 /* Fill in the next free callout structure. */ 859 new = SLIST_FIRST(&cc->cc_callfree); 860 if (new == NULL) 861 /* XXX Attempt to malloc first */ 862 panic("timeout table full"); 863 SLIST_REMOVE_HEAD(&cc->cc_callfree, c_links.sle); 864 callout_reset(new, to_ticks, ftn, arg); 865 handle.callout = new; 866 CC_UNLOCK(cc); 867 868 return (handle); 869} 870 871void 872untimeout(ftn, arg, handle) 873 timeout_t *ftn; 874 void *arg; 875 struct callout_handle handle; 876{ 877 struct callout_cpu *cc; 878 879 /* 880 * Check for a handle that was initialized 881 * by callout_handle_init, but never used 882 * for a real timeout. 883 */ 884 if (handle.callout == NULL) 885 return; 886 887 cc = callout_lock(handle.callout); 888 if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) 889 callout_stop(handle.callout); 890 CC_UNLOCK(cc); 891} 892 893void 894callout_handle_init(struct callout_handle *handle) 895{ 896 handle->callout = NULL; 897} 898 899/* 900 * New interface; clients allocate their own callout structures. 901 * 902 * callout_reset() - establish or change a timeout 903 * callout_stop() - disestablish a timeout 904 * callout_init() - initialize a callout structure so that it can 905 * safely be passed to callout_reset() and callout_stop() 906 * 907 * <sys/callout.h> defines three convenience macros: 908 * 909 * callout_active() - returns truth if callout has not been stopped, 910 * drained, or deactivated since the last time the callout was 911 * reset. 912 * callout_pending() - returns truth if callout is still waiting for timeout 913 * callout_deactivate() - marks the callout as having been serviced 914 */ 915int 916callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t precision, 917 void (*ftn)(void *), void *arg, int cpu, int flags) 918{ 919 sbintime_t to_sbt, pr; 920 struct callout_cpu *cc; 921 int cancelled, direct; 922 int ignore_cpu=0; 923 924 cancelled = 0; 925 if (cpu == -1) { 926 ignore_cpu = 1; 927 } else if ((cpu >= MAXCPU) || 928 ((CC_CPU(cpu))->cc_inited == 0)) { 929 /* Invalid CPU spec */ 930 panic("Invalid CPU in callout %d", cpu); 931 } 932 if (flags & C_ABSOLUTE) { 933 to_sbt = sbt; 934 } else { 935 if ((flags & C_HARDCLOCK) && (sbt < tick_sbt)) 936 sbt = tick_sbt; 937 if ((flags & C_HARDCLOCK) || 938#ifdef NO_EVENTTIMERS 939 sbt >= sbt_timethreshold) { 940 to_sbt = getsbinuptime(); 941 942 /* Add safety belt for the case of hz > 1000. */ 943 to_sbt += tc_tick_sbt - tick_sbt; 944#else 945 sbt >= sbt_tickthreshold) { 946 /* 947 * Obtain the time of the last hardclock() call on 948 * this CPU directly from the kern_clocksource.c. 949 * This value is per-CPU, but it is equal for all 950 * active ones. 951 */ 952#ifdef __LP64__ 953 to_sbt = DPCPU_GET(hardclocktime); 954#else 955 spinlock_enter(); 956 to_sbt = DPCPU_GET(hardclocktime); 957 spinlock_exit(); 958#endif 959#endif 960 if ((flags & C_HARDCLOCK) == 0) 961 to_sbt += tick_sbt; 962 } else 963 to_sbt = sbinuptime(); 964 if (INT64_MAX - to_sbt < sbt) 965 to_sbt = INT64_MAX; 966 else 967 to_sbt += sbt; 968 pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : 969 sbt >> C_PRELGET(flags)); 970 if (pr > precision) 971 precision = pr; 972 } 973 /* 974 * This flag used to be added by callout_cc_add, but the 975 * first time you call this we could end up with the 976 * wrong direct flag if we don't do it before we add. 977 */ 978 if (flags & C_DIRECT_EXEC) { 979 direct = 1; 980 } else { 981 direct = 0; 982 } 983 KASSERT(!direct || c->c_lock == NULL, 984 ("%s: direct callout %p has lock", __func__, c)); 985 cc = callout_lock(c); 986 /* 987 * Don't allow migration of pre-allocated callouts lest they 988 * become unbalanced or handle the case where the user does 989 * not care. 990 */ 991 if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) || 992 ignore_cpu) { 993 cpu = c->c_cpu; 994 } 995 996 if (cc_exec_curr(cc, direct) == c) { 997 /* 998 * We're being asked to reschedule a callout which is 999 * currently in progress. If there is a lock then we 1000 * can cancel the callout if it has not really started. 1001 */ 1002 if (c->c_lock != NULL && !cc_exec_cancel(cc, direct)) 1003 cancelled = cc_exec_cancel(cc, direct) = true; 1004 if (cc_exec_waiting(cc, direct)) { 1005 /* 1006 * Someone has called callout_drain to kill this 1007 * callout. Don't reschedule. 1008 */ 1009 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 1010 cancelled ? "cancelled" : "failed to cancel", 1011 c, c->c_func, c->c_arg); 1012 CC_UNLOCK(cc); 1013 return (cancelled); 1014 } 1015#ifdef SMP 1016 if (callout_migrating(c)) { 1017 /* 1018 * This only occurs when a second callout_reset_sbt_on 1019 * is made after a previous one moved it into 1020 * deferred migration (below). Note we do *not* change 1021 * the prev_cpu even though the previous target may 1022 * be different. 1023 */ 1024 cc_migration_cpu(cc, direct) = cpu; 1025 cc_migration_time(cc, direct) = to_sbt; 1026 cc_migration_prec(cc, direct) = precision; 1027 cc_migration_func(cc, direct) = ftn; 1028 cc_migration_arg(cc, direct) = arg; 1029 cancelled = 1; 1030 CC_UNLOCK(cc); 1031 return (cancelled); 1032 } 1033#endif 1034 } 1035 if (c->c_iflags & CALLOUT_PENDING) { 1036 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1037 if (cc_exec_next(cc) == c) 1038 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1039 LIST_REMOVE(c, c_links.le); 1040 } else { 1041 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1042 } 1043 cancelled = 1; 1044 c->c_iflags &= ~ CALLOUT_PENDING; 1045 c->c_flags &= ~ CALLOUT_ACTIVE; 1046 } 1047 1048#ifdef SMP 1049 /* 1050 * If the callout must migrate try to perform it immediately. 1051 * If the callout is currently running, just defer the migration 1052 * to a more appropriate moment. 1053 */ 1054 if (c->c_cpu != cpu) { 1055 if (cc_exec_curr(cc, direct) == c) { 1056 /* 1057 * Pending will have been removed since we are 1058 * actually executing the callout on another 1059 * CPU. That callout should be waiting on the 1060 * lock the caller holds. If we set both 1061 * active/and/pending after we return and the 1062 * lock on the executing callout proceeds, it 1063 * will then see pending is true and return. 1064 * At the return from the actual callout execution 1065 * the migration will occur in softclock_call_cc 1066 * and this new callout will be placed on the 1067 * new CPU via a call to callout_cpu_switch() which 1068 * will get the lock on the right CPU followed 1069 * by a call callout_cc_add() which will add it there. 1070 * (see above in softclock_call_cc()). 1071 */ 1072 cc_migration_cpu(cc, direct) = cpu; 1073 cc_migration_time(cc, direct) = to_sbt; 1074 cc_migration_prec(cc, direct) = precision; 1075 cc_migration_func(cc, direct) = ftn; 1076 cc_migration_arg(cc, direct) = arg; 1077 c->c_iflags |= (CALLOUT_DFRMIGRATION | CALLOUT_PENDING); 1078 c->c_flags |= CALLOUT_ACTIVE; 1079 CTR6(KTR_CALLOUT, 1080 "migration of %p func %p arg %p in %d.%08x to %u deferred", 1081 c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1082 (u_int)(to_sbt & 0xffffffff), cpu); 1083 CC_UNLOCK(cc); 1084 return (cancelled); 1085 } 1086 cc = callout_cpu_switch(c, cc, cpu); 1087 } 1088#endif 1089 1090 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags); 1091 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", 1092 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1093 (u_int)(to_sbt & 0xffffffff)); 1094 CC_UNLOCK(cc); 1095 1096 return (cancelled); 1097} 1098 1099/* 1100 * Common idioms that can be optimized in the future. 1101 */ 1102int 1103callout_schedule_on(struct callout *c, int to_ticks, int cpu) 1104{ 1105 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 1106} 1107 1108int 1109callout_schedule(struct callout *c, int to_ticks) 1110{ 1111 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 1112} 1113 1114int 1115_callout_stop_safe(c, flags) 1116 struct callout *c; 1117 int flags; 1118{ 1119 struct callout_cpu *cc, *old_cc; 1120 struct lock_class *class; 1121 int direct, sq_locked, use_lock; 1122 int not_on_a_list; 1123 1124 /* 1125 * Some old subsystems don't hold Giant while running a callout_stop(), 1126 * so just discard this check for the moment. 1127 */ 1128 if ((flags & CS_DRAIN) == 0 && c->c_lock != NULL) { 1129 if (c->c_lock == &Giant.lock_object) 1130 use_lock = mtx_owned(&Giant); 1131 else { 1132 use_lock = 1; 1133 class = LOCK_CLASS(c->c_lock); 1134 class->lc_assert(c->c_lock, LA_XLOCKED); 1135 } 1136 } else 1137 use_lock = 0; 1138 if (c->c_iflags & CALLOUT_DIRECT) { 1139 direct = 1; 1140 } else { 1141 direct = 0; 1142 } 1143 sq_locked = 0; 1144 old_cc = NULL; 1145again: 1146 cc = callout_lock(c); 1147 1148 if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) == 1149 (CALLOUT_DFRMIGRATION | CALLOUT_PENDING) && 1150 ((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) { 1151 /* 1152 * Special case where this slipped in while we 1153 * were migrating *as* the callout is about to 1154 * execute. The caller probably holds the lock 1155 * the callout wants. 1156 * 1157 * Get rid of the migration first. Then set 1158 * the flag that tells this code *not* to 1159 * try to remove it from any lists (its not 1160 * on one yet). When the callout wheel runs, 1161 * it will ignore this callout. 1162 */ 1163 c->c_iflags &= ~CALLOUT_PENDING; 1164 c->c_flags &= ~CALLOUT_ACTIVE; 1165 not_on_a_list = 1; 1166 } else { 1167 not_on_a_list = 0; 1168 } 1169 1170 /* 1171 * If the callout was migrating while the callout cpu lock was 1172 * dropped, just drop the sleepqueue lock and check the states 1173 * again. 1174 */ 1175 if (sq_locked != 0 && cc != old_cc) { 1176#ifdef SMP 1177 CC_UNLOCK(cc); 1178 sleepq_release(&cc_exec_waiting(old_cc, direct)); 1179 sq_locked = 0; 1180 old_cc = NULL; 1181 goto again; 1182#else 1183 panic("migration should not happen"); 1184#endif 1185 } 1186 1187 /* 1188 * If the callout isn't pending, it's not on the queue, so 1189 * don't attempt to remove it from the queue. We can try to 1190 * stop it by other means however. 1191 */ 1192 if (!(c->c_iflags & CALLOUT_PENDING)) { 1193 c->c_flags &= ~CALLOUT_ACTIVE; 1194 1195 /* 1196 * If it wasn't on the queue and it isn't the current 1197 * callout, then we can't stop it, so just bail. 1198 */ 1199 if (cc_exec_curr(cc, direct) != c) { 1200 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1201 c, c->c_func, c->c_arg); 1202 CC_UNLOCK(cc); 1203 if (sq_locked) 1204 sleepq_release(&cc_exec_waiting(cc, direct)); 1205 return (0); 1206 } 1207 1208 if ((flags & CS_DRAIN) != 0) { 1209 /* 1210 * The current callout is running (or just 1211 * about to run) and blocking is allowed, so 1212 * just wait for the current invocation to 1213 * finish. 1214 */ 1215 while (cc_exec_curr(cc, direct) == c) { 1216 /* 1217 * Use direct calls to sleepqueue interface 1218 * instead of cv/msleep in order to avoid 1219 * a LOR between cc_lock and sleepqueue 1220 * chain spinlocks. This piece of code 1221 * emulates a msleep_spin() call actually. 1222 * 1223 * If we already have the sleepqueue chain 1224 * locked, then we can safely block. If we 1225 * don't already have it locked, however, 1226 * we have to drop the cc_lock to lock 1227 * it. This opens several races, so we 1228 * restart at the beginning once we have 1229 * both locks. If nothing has changed, then 1230 * we will end up back here with sq_locked 1231 * set. 1232 */ 1233 if (!sq_locked) { 1234 CC_UNLOCK(cc); 1235 sleepq_lock( 1236 &cc_exec_waiting(cc, direct)); 1237 sq_locked = 1; 1238 old_cc = cc; 1239 goto again; 1240 } 1241 1242 /* 1243 * Migration could be cancelled here, but 1244 * as long as it is still not sure when it 1245 * will be packed up, just let softclock() 1246 * take care of it. 1247 */ 1248 cc_exec_waiting(cc, direct) = true; 1249 DROP_GIANT(); 1250 CC_UNLOCK(cc); 1251 sleepq_add( 1252 &cc_exec_waiting(cc, direct), 1253 &cc->cc_lock.lock_object, "codrain", 1254 SLEEPQ_SLEEP, 0); 1255 sleepq_wait( 1256 &cc_exec_waiting(cc, direct), 1257 0); 1258 sq_locked = 0; 1259 old_cc = NULL; 1260 1261 /* Reacquire locks previously released. */ 1262 PICKUP_GIANT(); 1263 CC_LOCK(cc); 1264 } 1265 } else if (use_lock && 1266 !cc_exec_cancel(cc, direct)) { 1267 1268 /* 1269 * The current callout is waiting for its 1270 * lock which we hold. Cancel the callout 1271 * and return. After our caller drops the 1272 * lock, the callout will be skipped in 1273 * softclock(). 1274 */ 1275 cc_exec_cancel(cc, direct) = true; 1276 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1277 c, c->c_func, c->c_arg); 1278 KASSERT(!cc_cce_migrating(cc, direct), 1279 ("callout wrongly scheduled for migration")); 1280 if (callout_migrating(c)) { 1281 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1282#ifdef SMP 1283 cc_migration_cpu(cc, direct) = CPUBLOCK; 1284 cc_migration_time(cc, direct) = 0; 1285 cc_migration_prec(cc, direct) = 0; 1286 cc_migration_func(cc, direct) = NULL; 1287 cc_migration_arg(cc, direct) = NULL; 1288#endif 1289 } 1290 CC_UNLOCK(cc); 1291 KASSERT(!sq_locked, ("sleepqueue chain locked")); 1292 return (1); 1293 } else if (callout_migrating(c)) { 1294 /* 1295 * The callout is currently being serviced 1296 * and the "next" callout is scheduled at 1297 * its completion with a migration. We remove 1298 * the migration flag so it *won't* get rescheduled, 1299 * but we can't stop the one thats running so 1300 * we return 0. 1301 */ 1302 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1303#ifdef SMP 1304 /* 1305 * We can't call cc_cce_cleanup here since 1306 * if we do it will remove .ce_curr and 1307 * its still running. This will prevent a 1308 * reschedule of the callout when the 1309 * execution completes. 1310 */ 1311 cc_migration_cpu(cc, direct) = CPUBLOCK; 1312 cc_migration_time(cc, direct) = 0; 1313 cc_migration_prec(cc, direct) = 0; 1314 cc_migration_func(cc, direct) = NULL; 1315 cc_migration_arg(cc, direct) = NULL; 1316#endif 1317 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 1318 c, c->c_func, c->c_arg); 1319 CC_UNLOCK(cc); 1320 return ((flags & CS_MIGRBLOCK) != 0); 1321 } 1322 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1323 c, c->c_func, c->c_arg); 1324 CC_UNLOCK(cc); 1325 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 1326 return (0); 1327 } 1328 if (sq_locked) 1329 sleepq_release(&cc_exec_waiting(cc, direct)); 1330 1331 c->c_iflags &= ~CALLOUT_PENDING; 1332 c->c_flags &= ~CALLOUT_ACTIVE; 1333 1334 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1335 c, c->c_func, c->c_arg); 1336 if (not_on_a_list == 0) { 1337 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1338 if (cc_exec_next(cc) == c) 1339 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1340 LIST_REMOVE(c, c_links.le); 1341 } else { 1342 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1343 } 1344 } 1345 callout_cc_del(c, cc); 1346 CC_UNLOCK(cc); 1347 return (1); 1348} 1349 1350void 1351callout_init(c, mpsafe) 1352 struct callout *c; 1353 int mpsafe; 1354{ 1355 bzero(c, sizeof *c); 1356 if (mpsafe) { 1357 c->c_lock = NULL; 1358 c->c_iflags = CALLOUT_RETURNUNLOCKED; 1359 } else { 1360 c->c_lock = &Giant.lock_object; 1361 c->c_iflags = 0; 1362 } 1363 c->c_cpu = timeout_cpu; 1364} 1365 1366void 1367_callout_init_lock(c, lock, flags) 1368 struct callout *c; 1369 struct lock_object *lock; 1370 int flags; 1371{ 1372 bzero(c, sizeof *c); 1373 c->c_lock = lock; 1374 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1375 ("callout_init_lock: bad flags %d", flags)); 1376 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1377 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1378 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & 1379 (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class", 1380 __func__)); 1381 c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1382 c->c_cpu = timeout_cpu; 1383} 1384 1385#ifdef APM_FIXUP_CALLTODO 1386/* 1387 * Adjust the kernel calltodo timeout list. This routine is used after 1388 * an APM resume to recalculate the calltodo timer list values with the 1389 * number of hz's we have been sleeping. The next hardclock() will detect 1390 * that there are fired timers and run softclock() to execute them. 1391 * 1392 * Please note, I have not done an exhaustive analysis of what code this 1393 * might break. I am motivated to have my select()'s and alarm()'s that 1394 * have expired during suspend firing upon resume so that the applications 1395 * which set the timer can do the maintanence the timer was for as close 1396 * as possible to the originally intended time. Testing this code for a 1397 * week showed that resuming from a suspend resulted in 22 to 25 timers 1398 * firing, which seemed independent on whether the suspend was 2 hours or 1399 * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu> 1400 */ 1401void 1402adjust_timeout_calltodo(time_change) 1403 struct timeval *time_change; 1404{ 1405 register struct callout *p; 1406 unsigned long delta_ticks; 1407 1408 /* 1409 * How many ticks were we asleep? 1410 * (stolen from tvtohz()). 1411 */ 1412 1413 /* Don't do anything */ 1414 if (time_change->tv_sec < 0) 1415 return; 1416 else if (time_change->tv_sec <= LONG_MAX / 1000000) 1417 delta_ticks = (time_change->tv_sec * 1000000 + 1418 time_change->tv_usec + (tick - 1)) / tick + 1; 1419 else if (time_change->tv_sec <= LONG_MAX / hz) 1420 delta_ticks = time_change->tv_sec * hz + 1421 (time_change->tv_usec + (tick - 1)) / tick + 1; 1422 else 1423 delta_ticks = LONG_MAX; 1424 1425 if (delta_ticks > INT_MAX) 1426 delta_ticks = INT_MAX; 1427 1428 /* 1429 * Now rip through the timer calltodo list looking for timers 1430 * to expire. 1431 */ 1432 1433 /* don't collide with softclock() */ 1434 CC_LOCK(cc); 1435 for (p = calltodo.c_next; p != NULL; p = p->c_next) { 1436 p->c_time -= delta_ticks; 1437 1438 /* Break if the timer had more time on it than delta_ticks */ 1439 if (p->c_time > 0) 1440 break; 1441 1442 /* take back the ticks the timer didn't use (p->c_time <= 0) */ 1443 delta_ticks = -p->c_time; 1444 } 1445 CC_UNLOCK(cc); 1446 1447 return; 1448} 1449#endif /* APM_FIXUP_CALLTODO */ 1450 1451static int 1452flssbt(sbintime_t sbt) 1453{ 1454 1455 sbt += (uint64_t)sbt >> 1; 1456 if (sizeof(long) >= sizeof(sbintime_t)) 1457 return (flsl(sbt)); 1458 if (sbt >= SBT_1S) 1459 return (flsl(((uint64_t)sbt) >> 32) + 32); 1460 return (flsl(sbt)); 1461} 1462 1463/* 1464 * Dump immediate statistic snapshot of the scheduled callouts. 1465 */ 1466static int 1467sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1468{ 1469 struct callout *tmp; 1470 struct callout_cpu *cc; 1471 struct callout_list *sc; 1472 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; 1473 int ct[64], cpr[64], ccpbk[32]; 1474 int error, val, i, count, tcum, pcum, maxc, c, medc; 1475#ifdef SMP 1476 int cpu; 1477#endif 1478 1479 val = 0; 1480 error = sysctl_handle_int(oidp, &val, 0, req); 1481 if (error != 0 || req->newptr == NULL) 1482 return (error); 1483 count = maxc = 0; 1484 st = spr = maxt = maxpr = 0; 1485 bzero(ccpbk, sizeof(ccpbk)); 1486 bzero(ct, sizeof(ct)); 1487 bzero(cpr, sizeof(cpr)); 1488 now = sbinuptime(); 1489#ifdef SMP 1490 CPU_FOREACH(cpu) { 1491 cc = CC_CPU(cpu); 1492#else 1493 cc = CC_CPU(timeout_cpu); 1494#endif 1495 CC_LOCK(cc); 1496 for (i = 0; i < callwheelsize; i++) { 1497 sc = &cc->cc_callwheel[i]; 1498 c = 0; 1499 LIST_FOREACH(tmp, sc, c_links.le) { 1500 c++; 1501 t = tmp->c_time - now; 1502 if (t < 0) 1503 t = 0; 1504 st += t / SBT_1US; 1505 spr += tmp->c_precision / SBT_1US; 1506 if (t > maxt) 1507 maxt = t; 1508 if (tmp->c_precision > maxpr) 1509 maxpr = tmp->c_precision; 1510 ct[flssbt(t)]++; 1511 cpr[flssbt(tmp->c_precision)]++; 1512 } 1513 if (c > maxc) 1514 maxc = c; 1515 ccpbk[fls(c + c / 2)]++; 1516 count += c; 1517 } 1518 CC_UNLOCK(cc); 1519#ifdef SMP 1520 } 1521#endif 1522 1523 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1524 tcum += ct[i]; 1525 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1526 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) 1527 pcum += cpr[i]; 1528 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1529 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1530 c += ccpbk[i]; 1531 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1532 1533 printf("Scheduled callouts statistic snapshot:\n"); 1534 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1535 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1536 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1537 medc, 1538 count / callwheelsize / mp_ncpus, 1539 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1540 maxc); 1541 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1542 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1543 (st / count) / 1000000, (st / count) % 1000000, 1544 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); 1545 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1546 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, 1547 (spr / count) / 1000000, (spr / count) % 1000000, 1548 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); 1549 printf(" Distribution: \tbuckets\t time\t tcum\t" 1550 " prec\t pcum\n"); 1551 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1552 if (ct[i] == 0 && cpr[i] == 0) 1553 continue; 1554 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1555 tcum += ct[i]; 1556 pcum += cpr[i]; 1557 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", 1558 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1559 i - 1 - (32 - CC_HASH_SHIFT), 1560 ct[i], tcum, cpr[i], pcum); 1561 } 1562 return (error); 1563} 1564SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1565 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1566 0, 0, sysctl_kern_callout_stat, "I", 1567 "Dump immediate statistic snapshot of the scheduled callouts"); 1568