1/*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37#include <sys/cdefs.h> 38#include "opt_callout_profiling.h" 39#include "opt_ddb.h" 40#include "opt_rss.h" 41 42#include <sys/param.h> 43#include <sys/systm.h> 44#include <sys/bus.h> 45#include <sys/callout.h> 46#include <sys/domainset.h> 47#include <sys/file.h> 48#include <sys/interrupt.h> 49#include <sys/kernel.h> 50#include <sys/ktr.h> 51#include <sys/kthread.h> 52#include <sys/lock.h> 53#include <sys/malloc.h> 54#include <sys/mutex.h> 55#include <sys/proc.h> 56#include <sys/random.h> 57#include <sys/sched.h> 58#include <sys/sdt.h> 59#include <sys/sleepqueue.h> 60#include <sys/sysctl.h> 61#include <sys/smp.h> 62#include <sys/unistd.h> 63 64#ifdef DDB 65#include <ddb/ddb.h> 66#include <ddb/db_sym.h> 67#include <machine/_inttypes.h> 68#endif 69 70#ifdef SMP 71#include <machine/cpu.h> 72#endif 73 74DPCPU_DECLARE(sbintime_t, hardclocktime); 75 76SDT_PROVIDER_DEFINE(callout_execute); 77SDT_PROBE_DEFINE1(callout_execute, , , callout__start, "struct callout *"); 78SDT_PROBE_DEFINE1(callout_execute, , , callout__end, "struct callout *"); 79 80static void softclock_thread(void *arg); 81 82#ifdef CALLOUT_PROFILING 83static int avg_depth; 84SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, 85 "Average number of items examined per softclock call. Units = 1/1000"); 86static int avg_gcalls; 87SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, 88 "Average number of Giant callouts made per softclock call. Units = 1/1000"); 89static int avg_lockcalls; 90SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0, 91 "Average number of lock callouts made per softclock call. Units = 1/1000"); 92static int avg_mpcalls; 93SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, 94 "Average number of MP callouts made per softclock call. Units = 1/1000"); 95static int avg_depth_dir; 96SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0, 97 "Average number of direct callouts examined per callout_process call. " 98 "Units = 1/1000"); 99static int avg_lockcalls_dir; 100SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD, 101 &avg_lockcalls_dir, 0, "Average number of lock direct callouts made per " 102 "callout_process call. Units = 1/1000"); 103static int avg_mpcalls_dir; 104SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir, 105 0, "Average number of MP direct callouts made per callout_process call. " 106 "Units = 1/1000"); 107#endif 108 109static int ncallout; 110SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &ncallout, 0, 111 "Number of entries in callwheel and size of timeout() preallocation"); 112 113#ifdef RSS 114static int pin_default_swi = 1; 115static int pin_pcpu_swi = 1; 116#else 117static int pin_default_swi = 0; 118static int pin_pcpu_swi = 0; 119#endif 120 121SYSCTL_INT(_kern, OID_AUTO, pin_default_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_default_swi, 122 0, "Pin the default (non-per-cpu) swi (shared with PCPU 0 swi)"); 123SYSCTL_INT(_kern, OID_AUTO, pin_pcpu_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_pcpu_swi, 124 0, "Pin the per-CPU swis (except PCPU 0, which is also default)"); 125 126/* 127 * TODO: 128 * allocate more timeout table slots when table overflows. 129 */ 130static u_int __read_mostly callwheelsize; 131static u_int __read_mostly callwheelmask; 132 133/* 134 * The callout cpu exec entities represent informations necessary for 135 * describing the state of callouts currently running on the CPU and the ones 136 * necessary for migrating callouts to the new callout cpu. In particular, 137 * the first entry of the array cc_exec_entity holds informations for callout 138 * running in SWI thread context, while the second one holds informations 139 * for callout running directly from hardware interrupt context. 140 * The cached informations are very important for deferring migration when 141 * the migrating callout is already running. 142 */ 143struct cc_exec { 144 struct callout *cc_curr; 145 void *cc_last_func; 146 void *cc_last_arg; 147#ifdef SMP 148 callout_func_t *ce_migration_func; 149 void *ce_migration_arg; 150 sbintime_t ce_migration_time; 151 sbintime_t ce_migration_prec; 152 int ce_migration_cpu; 153#endif 154 bool cc_cancel; 155 bool cc_waiting; 156}; 157 158/* 159 * There is one struct callout_cpu per cpu, holding all relevant 160 * state for the callout processing thread on the individual CPU. 161 */ 162struct callout_cpu { 163 struct mtx_padalign cc_lock; 164 struct cc_exec cc_exec_entity[2]; 165 struct callout *cc_next; 166 struct callout_list *cc_callwheel; 167 struct callout_tailq cc_expireq; 168 sbintime_t cc_firstevent; 169 sbintime_t cc_lastscan; 170 struct thread *cc_thread; 171 u_int cc_bucket; 172#ifdef KTR 173 char cc_ktr_event_name[20]; 174#endif 175}; 176 177#define callout_migrating(c) ((c)->c_iflags & CALLOUT_DFRMIGRATION) 178 179#define cc_exec_curr(cc, dir) cc->cc_exec_entity[dir].cc_curr 180#define cc_exec_last_func(cc, dir) cc->cc_exec_entity[dir].cc_last_func 181#define cc_exec_last_arg(cc, dir) cc->cc_exec_entity[dir].cc_last_arg 182#define cc_exec_next(cc) cc->cc_next 183#define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel 184#define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting 185#ifdef SMP 186#define cc_migration_func(cc, dir) cc->cc_exec_entity[dir].ce_migration_func 187#define cc_migration_arg(cc, dir) cc->cc_exec_entity[dir].ce_migration_arg 188#define cc_migration_cpu(cc, dir) cc->cc_exec_entity[dir].ce_migration_cpu 189#define cc_migration_time(cc, dir) cc->cc_exec_entity[dir].ce_migration_time 190#define cc_migration_prec(cc, dir) cc->cc_exec_entity[dir].ce_migration_prec 191 192DPCPU_DEFINE_STATIC(struct callout_cpu, cc_cpu); 193#define CPUBLOCK MAXCPU 194#define CC_CPU(cpu) DPCPU_ID_PTR(cpu, cc_cpu) 195#define CC_SELF() CC_CPU(PCPU_GET(cpuid)) 196#else 197static struct callout_cpu cc_cpu; 198#define CC_CPU(cpu) (&cc_cpu) 199#define CC_SELF() (&cc_cpu) 200#endif 201#define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) 202#define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) 203#define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) 204 205static int __read_mostly cc_default_cpu; 206 207static void callout_cpu_init(struct callout_cpu *cc, int cpu); 208static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, 209#ifdef CALLOUT_PROFILING 210 int *mpcalls, int *lockcalls, int *gcalls, 211#endif 212 int direct); 213 214static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); 215 216/** 217 * Locked by cc_lock: 218 * cc_curr - If a callout is in progress, it is cc_curr. 219 * If cc_curr is non-NULL, threads waiting in 220 * callout_drain() will be woken up as soon as the 221 * relevant callout completes. 222 * cc_cancel - Changing to 1 with both callout_lock and cc_lock held 223 * guarantees that the current callout will not run. 224 * The softclock_call_cc() function sets this to 0 before it 225 * drops callout_lock to acquire c_lock, and it calls 226 * the handler only if curr_cancelled is still 0 after 227 * cc_lock is successfully acquired. 228 * cc_waiting - If a thread is waiting in callout_drain(), then 229 * callout_wait is nonzero. Set only when 230 * cc_curr is non-NULL. 231 */ 232 233/* 234 * Resets the execution entity tied to a specific callout cpu. 235 */ 236static void 237cc_cce_cleanup(struct callout_cpu *cc, int direct) 238{ 239 240 cc_exec_curr(cc, direct) = NULL; 241 cc_exec_cancel(cc, direct) = false; 242 cc_exec_waiting(cc, direct) = false; 243#ifdef SMP 244 cc_migration_cpu(cc, direct) = CPUBLOCK; 245 cc_migration_time(cc, direct) = 0; 246 cc_migration_prec(cc, direct) = 0; 247 cc_migration_func(cc, direct) = NULL; 248 cc_migration_arg(cc, direct) = NULL; 249#endif 250} 251 252/* 253 * Checks if migration is requested by a specific callout cpu. 254 */ 255static int 256cc_cce_migrating(struct callout_cpu *cc, int direct) 257{ 258 259#ifdef SMP 260 return (cc_migration_cpu(cc, direct) != CPUBLOCK); 261#else 262 return (0); 263#endif 264} 265 266/* 267 * Kernel low level callwheel initialization 268 * called on the BSP during kernel startup. 269 */ 270static void 271callout_callwheel_init(void *dummy) 272{ 273 struct callout_cpu *cc; 274 int cpu; 275 276 /* 277 * Calculate the size of the callout wheel and the preallocated 278 * timeout() structures. 279 * XXX: Clip callout to result of previous function of maxusers 280 * maximum 384. This is still huge, but acceptable. 281 */ 282 ncallout = imin(16 + maxproc + maxfiles, 18508); 283 TUNABLE_INT_FETCH("kern.ncallout", &ncallout); 284 285 /* 286 * Calculate callout wheel size, should be next power of two higher 287 * than 'ncallout'. 288 */ 289 callwheelsize = 1 << fls(ncallout); 290 callwheelmask = callwheelsize - 1; 291 292 /* 293 * Fetch whether we're pinning the swi's or not. 294 */ 295 TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi); 296 TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi); 297 298 /* 299 * Initialize callout wheels. The software interrupt threads 300 * are created later. 301 */ 302 cc_default_cpu = PCPU_GET(cpuid); 303 CPU_FOREACH(cpu) { 304 cc = CC_CPU(cpu); 305 callout_cpu_init(cc, cpu); 306 } 307} 308SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); 309 310/* 311 * Initialize the per-cpu callout structures. 312 */ 313static void 314callout_cpu_init(struct callout_cpu *cc, int cpu) 315{ 316 int i; 317 318 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN); 319 cc->cc_callwheel = malloc_domainset(sizeof(struct callout_list) * 320 callwheelsize, M_CALLOUT, 321 DOMAINSET_PREF(pcpu_find(cpu)->pc_domain), M_WAITOK); 322 for (i = 0; i < callwheelsize; i++) 323 LIST_INIT(&cc->cc_callwheel[i]); 324 TAILQ_INIT(&cc->cc_expireq); 325 cc->cc_firstevent = SBT_MAX; 326 for (i = 0; i < 2; i++) 327 cc_cce_cleanup(cc, i); 328#ifdef KTR 329 snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name), 330 "callwheel cpu %d", cpu); 331#endif 332} 333 334#ifdef SMP 335/* 336 * Switches the cpu tied to a specific callout. 337 * The function expects a locked incoming callout cpu and returns with 338 * locked outcoming callout cpu. 339 */ 340static struct callout_cpu * 341callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu) 342{ 343 struct callout_cpu *new_cc; 344 345 MPASS(c != NULL && cc != NULL); 346 CC_LOCK_ASSERT(cc); 347 348 /* 349 * Avoid interrupts and preemption firing after the callout cpu 350 * is blocked in order to avoid deadlocks as the new thread 351 * may be willing to acquire the callout cpu lock. 352 */ 353 c->c_cpu = CPUBLOCK; 354 spinlock_enter(); 355 CC_UNLOCK(cc); 356 new_cc = CC_CPU(new_cpu); 357 CC_LOCK(new_cc); 358 spinlock_exit(); 359 c->c_cpu = new_cpu; 360 return (new_cc); 361} 362#endif 363 364/* 365 * Start softclock threads. 366 */ 367static void 368start_softclock(void *dummy) 369{ 370 struct proc *p; 371 struct thread *td; 372 struct callout_cpu *cc; 373 int cpu, error; 374 bool pin_swi; 375 376 p = NULL; 377 CPU_FOREACH(cpu) { 378 cc = CC_CPU(cpu); 379 error = kproc_kthread_add(softclock_thread, cc, &p, &td, 380 RFSTOPPED, 0, "clock", "clock (%d)", cpu); 381 if (error != 0) 382 panic("failed to create softclock thread for cpu %d: %d", 383 cpu, error); 384 CC_LOCK(cc); 385 cc->cc_thread = td; 386 thread_lock(td); 387 sched_class(td, PRI_ITHD); 388 sched_ithread_prio(td, PI_SOFTCLOCK); 389 TD_SET_IWAIT(td); 390 thread_lock_set(td, (struct mtx *)&cc->cc_lock); 391 thread_unlock(td); 392 if (cpu == cc_default_cpu) 393 pin_swi = pin_default_swi; 394 else 395 pin_swi = pin_pcpu_swi; 396 if (pin_swi) { 397 error = cpuset_setithread(td->td_tid, cpu); 398 if (error != 0) 399 printf("%s: %s clock couldn't be pinned to cpu %d: %d\n", 400 __func__, cpu == cc_default_cpu ? 401 "default" : "per-cpu", cpu, error); 402 } 403 } 404} 405SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); 406 407#define CC_HASH_SHIFT 8 408 409static inline u_int 410callout_hash(sbintime_t sbt) 411{ 412 413 return (sbt >> (32 - CC_HASH_SHIFT)); 414} 415 416static inline u_int 417callout_get_bucket(sbintime_t sbt) 418{ 419 420 return (callout_hash(sbt) & callwheelmask); 421} 422 423void 424callout_process(sbintime_t now) 425{ 426 struct callout_entropy { 427 struct callout_cpu *cc; 428 struct thread *td; 429 sbintime_t now; 430 } entropy; 431 struct callout *c, *next; 432 struct callout_cpu *cc; 433 struct callout_list *sc; 434 struct thread *td; 435 sbintime_t first, last, lookahead, max, tmp_max; 436 u_int firstb, lastb, nowb; 437#ifdef CALLOUT_PROFILING 438 int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0; 439#endif 440 441 cc = CC_SELF(); 442 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET); 443 444 /* Compute the buckets of the last scan and present times. */ 445 firstb = callout_hash(cc->cc_lastscan); 446 cc->cc_lastscan = now; 447 nowb = callout_hash(now); 448 449 /* Compute the last bucket and minimum time of the bucket after it. */ 450 if (nowb == firstb) 451 lookahead = (SBT_1S / 16); 452 else if (nowb - firstb == 1) 453 lookahead = (SBT_1S / 8); 454 else 455 lookahead = SBT_1S; 456 first = last = now; 457 first += (lookahead / 2); 458 last += lookahead; 459 last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); 460 lastb = callout_hash(last) - 1; 461 max = last; 462 463 /* 464 * Check if we wrapped around the entire wheel from the last scan. 465 * In case, we need to scan entirely the wheel for pending callouts. 466 */ 467 if (lastb - firstb >= callwheelsize) { 468 lastb = firstb + callwheelsize - 1; 469 if (nowb - firstb >= callwheelsize) 470 nowb = lastb; 471 } 472 473 /* Iterate callwheel from firstb to nowb and then up to lastb. */ 474 do { 475 sc = &cc->cc_callwheel[firstb & callwheelmask]; 476 LIST_FOREACH_SAFE(c, sc, c_links.le, next) { 477 /* Run the callout if present time within allowed. */ 478 if (c->c_time <= now) { 479 /* 480 * Consumer told us the callout may be run 481 * directly from hardware interrupt context. 482 */ 483 if (c->c_iflags & CALLOUT_DIRECT) { 484#ifdef CALLOUT_PROFILING 485 ++depth_dir; 486#endif 487 cc_exec_next(cc) = next; 488 cc->cc_bucket = firstb & callwheelmask; 489 LIST_REMOVE(c, c_links.le); 490 softclock_call_cc(c, cc, 491#ifdef CALLOUT_PROFILING 492 &mpcalls_dir, &lockcalls_dir, NULL, 493#endif 494 1); 495 next = cc_exec_next(cc); 496 cc_exec_next(cc) = NULL; 497 } else { 498 LIST_REMOVE(c, c_links.le); 499 TAILQ_INSERT_TAIL(&cc->cc_expireq, 500 c, c_links.tqe); 501 c->c_iflags |= CALLOUT_PROCESSED; 502 } 503 } else if (c->c_time >= max) { 504 /* 505 * Skip events in the distant future. 506 */ 507 ; 508 } else if (c->c_time > last) { 509 /* 510 * Event minimal time is bigger than present 511 * maximal time, so it cannot be aggregated. 512 */ 513 lastb = nowb; 514 } else { 515 /* 516 * Update first and last time, respecting this 517 * event. 518 */ 519 if (c->c_time < first) 520 first = c->c_time; 521 tmp_max = c->c_time + c->c_precision; 522 if (tmp_max < last) 523 last = tmp_max; 524 } 525 } 526 /* Proceed with the next bucket. */ 527 firstb++; 528 /* 529 * Stop if we looked after present time and found 530 * some event we can't execute at now. 531 * Stop if we looked far enough into the future. 532 */ 533 } while (((int)(firstb - lastb)) <= 0); 534 cc->cc_firstevent = last; 535 cpu_new_callout(curcpu, last, first); 536 537#ifdef CALLOUT_PROFILING 538 avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8; 539 avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8; 540 avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8; 541#endif 542 if (!TAILQ_EMPTY(&cc->cc_expireq)) { 543 entropy.cc = cc; 544 entropy.td = curthread; 545 entropy.now = now; 546 random_harvest_queue(&entropy, sizeof(entropy), RANDOM_CALLOUT); 547 548 td = cc->cc_thread; 549 if (TD_AWAITING_INTR(td)) { 550 thread_lock_block_wait(td); 551 THREAD_LOCK_ASSERT(td, MA_OWNED); 552 TD_CLR_IWAIT(td); 553 sched_wakeup(td, SRQ_INTR); 554 } else 555 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 556 } else 557 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 558} 559 560static struct callout_cpu * 561callout_lock(struct callout *c) 562{ 563 struct callout_cpu *cc; 564 int cpu; 565 566 for (;;) { 567 cpu = c->c_cpu; 568#ifdef SMP 569 if (cpu == CPUBLOCK) { 570 while (c->c_cpu == CPUBLOCK) 571 cpu_spinwait(); 572 continue; 573 } 574#endif 575 cc = CC_CPU(cpu); 576 CC_LOCK(cc); 577 if (cpu == c->c_cpu) 578 break; 579 CC_UNLOCK(cc); 580 } 581 return (cc); 582} 583 584static void 585callout_cc_add(struct callout *c, struct callout_cpu *cc, 586 sbintime_t sbt, sbintime_t precision, void (*func)(void *), 587 void *arg, int flags) 588{ 589 int bucket; 590 591 CC_LOCK_ASSERT(cc); 592 if (sbt < cc->cc_lastscan) 593 sbt = cc->cc_lastscan; 594 c->c_arg = arg; 595 c->c_iflags |= CALLOUT_PENDING; 596 c->c_iflags &= ~CALLOUT_PROCESSED; 597 c->c_flags |= CALLOUT_ACTIVE; 598 if (flags & C_DIRECT_EXEC) 599 c->c_iflags |= CALLOUT_DIRECT; 600 c->c_func = func; 601 c->c_time = sbt; 602 c->c_precision = precision; 603 bucket = callout_get_bucket(c->c_time); 604 CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x", 605 c, (int)(c->c_precision >> 32), 606 (u_int)(c->c_precision & 0xffffffff)); 607 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); 608 if (cc->cc_bucket == bucket) 609 cc_exec_next(cc) = c; 610 611 /* 612 * Inform the eventtimers(4) subsystem there's a new callout 613 * that has been inserted, but only if really required. 614 */ 615 if (SBT_MAX - c->c_time < c->c_precision) 616 c->c_precision = SBT_MAX - c->c_time; 617 sbt = c->c_time + c->c_precision; 618 if (sbt < cc->cc_firstevent) { 619 cc->cc_firstevent = sbt; 620 cpu_new_callout(c->c_cpu, sbt, c->c_time); 621 } 622} 623 624static void 625softclock_call_cc(struct callout *c, struct callout_cpu *cc, 626#ifdef CALLOUT_PROFILING 627 int *mpcalls, int *lockcalls, int *gcalls, 628#endif 629 int direct) 630{ 631 struct rm_priotracker tracker; 632 callout_func_t *c_func; 633 void *c_arg; 634 struct lock_class *class; 635 struct lock_object *c_lock; 636 uintptr_t lock_status; 637 int c_iflags; 638#ifdef SMP 639 struct callout_cpu *new_cc; 640 callout_func_t *new_func; 641 void *new_arg; 642 int flags, new_cpu; 643 sbintime_t new_prec, new_time; 644#endif 645#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 646 sbintime_t sbt1, sbt2; 647 struct timespec ts2; 648 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 649 static callout_func_t *lastfunc; 650#endif 651 652 KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING, 653 ("softclock_call_cc: pend %p %x", c, c->c_iflags)); 654 KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE, 655 ("softclock_call_cc: act %p %x", c, c->c_flags)); 656 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; 657 lock_status = 0; 658 if (c->c_iflags & CALLOUT_SHAREDLOCK) { 659 if (class == &lock_class_rm) 660 lock_status = (uintptr_t)&tracker; 661 else 662 lock_status = 1; 663 } 664 c_lock = c->c_lock; 665 c_func = c->c_func; 666 c_arg = c->c_arg; 667 c_iflags = c->c_iflags; 668 c->c_iflags &= ~CALLOUT_PENDING; 669 670 cc_exec_curr(cc, direct) = c; 671 cc_exec_last_func(cc, direct) = c_func; 672 cc_exec_last_arg(cc, direct) = c_arg; 673 cc_exec_cancel(cc, direct) = false; 674 CC_UNLOCK(cc); 675 if (c_lock != NULL) { 676 class->lc_lock(c_lock, lock_status); 677 /* 678 * The callout may have been cancelled 679 * while we switched locks. 680 */ 681 if (cc_exec_cancel(cc, direct)) { 682 class->lc_unlock(c_lock); 683 goto skip; 684 } 685 /* The callout cannot be stopped now. */ 686 cc_exec_cancel(cc, direct) = true; 687 if (c_lock == &Giant.lock_object) { 688#ifdef CALLOUT_PROFILING 689 (*gcalls)++; 690#endif 691 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", 692 c, c_func, c_arg); 693 } else { 694#ifdef CALLOUT_PROFILING 695 (*lockcalls)++; 696#endif 697 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", 698 c, c_func, c_arg); 699 } 700 } else { 701#ifdef CALLOUT_PROFILING 702 (*mpcalls)++; 703#endif 704 CTR3(KTR_CALLOUT, "callout %p func %p arg %p", 705 c, c_func, c_arg); 706 } 707 KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running", 708 "func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct); 709#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 710 sbt1 = sbinuptime(); 711#endif 712 THREAD_NO_SLEEPING(); 713 SDT_PROBE1(callout_execute, , , callout__start, c); 714 c_func(c_arg); 715 SDT_PROBE1(callout_execute, , , callout__end, c); 716 THREAD_SLEEPING_OK(); 717#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 718 sbt2 = sbinuptime(); 719 sbt2 -= sbt1; 720 if (sbt2 > maxdt) { 721 if (lastfunc != c_func || sbt2 > maxdt * 2) { 722 ts2 = sbttots(sbt2); 723 printf( 724 "Expensive callout(9) function: %p(%p) %jd.%09ld s\n", 725 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); 726 } 727 maxdt = sbt2; 728 lastfunc = c_func; 729 } 730#endif 731 KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle"); 732 CTR1(KTR_CALLOUT, "callout %p finished", c); 733 if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0) 734 class->lc_unlock(c_lock); 735skip: 736 CC_LOCK(cc); 737 KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr")); 738 cc_exec_curr(cc, direct) = NULL; 739 if (cc_exec_waiting(cc, direct)) { 740 /* 741 * There is someone waiting for the 742 * callout to complete. 743 * If the callout was scheduled for 744 * migration just cancel it. 745 */ 746 if (cc_cce_migrating(cc, direct)) { 747 cc_cce_cleanup(cc, direct); 748 749 /* 750 * It should be assert here that the callout is not 751 * destroyed but that is not easy. 752 */ 753 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 754 } 755 cc_exec_waiting(cc, direct) = false; 756 CC_UNLOCK(cc); 757 wakeup(&cc_exec_waiting(cc, direct)); 758 CC_LOCK(cc); 759 } else if (cc_cce_migrating(cc, direct)) { 760#ifdef SMP 761 /* 762 * If the callout was scheduled for 763 * migration just perform it now. 764 */ 765 new_cpu = cc_migration_cpu(cc, direct); 766 new_time = cc_migration_time(cc, direct); 767 new_prec = cc_migration_prec(cc, direct); 768 new_func = cc_migration_func(cc, direct); 769 new_arg = cc_migration_arg(cc, direct); 770 cc_cce_cleanup(cc, direct); 771 772 /* 773 * It should be assert here that the callout is not destroyed 774 * but that is not easy. 775 * 776 * As first thing, handle deferred callout stops. 777 */ 778 if (!callout_migrating(c)) { 779 CTR3(KTR_CALLOUT, 780 "deferred cancelled %p func %p arg %p", 781 c, new_func, new_arg); 782 return; 783 } 784 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 785 786 new_cc = callout_cpu_switch(c, cc, new_cpu); 787 flags = (direct) ? C_DIRECT_EXEC : 0; 788 callout_cc_add(c, new_cc, new_time, new_prec, new_func, 789 new_arg, flags); 790 CC_UNLOCK(new_cc); 791 CC_LOCK(cc); 792#else 793 panic("migration should not happen"); 794#endif 795 } 796} 797 798/* 799 * The callout mechanism is based on the work of Adam M. Costello and 800 * George Varghese, published in a technical report entitled "Redesigning 801 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 802 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 803 * used in this implementation was published by G. Varghese and T. Lauck in 804 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 805 * the Efficient Implementation of a Timer Facility" in the Proceedings of 806 * the 11th ACM Annual Symposium on Operating Systems Principles, 807 * Austin, Texas Nov 1987. 808 */ 809 810/* 811 * Software (low priority) clock interrupt thread handler. 812 * Run periodic events from timeout queue. 813 */ 814static void 815softclock_thread(void *arg) 816{ 817 struct thread *td = curthread; 818 struct callout_cpu *cc; 819 struct callout *c; 820#ifdef CALLOUT_PROFILING 821 int depth, gcalls, lockcalls, mpcalls; 822#endif 823 824 cc = (struct callout_cpu *)arg; 825 CC_LOCK(cc); 826 for (;;) { 827 while (TAILQ_EMPTY(&cc->cc_expireq)) { 828 /* 829 * Use CC_LOCK(cc) as the thread_lock while 830 * idle. 831 */ 832 thread_lock(td); 833 thread_lock_set(td, (struct mtx *)&cc->cc_lock); 834 TD_SET_IWAIT(td); 835 mi_switch(SW_VOL | SWT_IWAIT); 836 837 /* mi_switch() drops thread_lock(). */ 838 CC_LOCK(cc); 839 } 840 841#ifdef CALLOUT_PROFILING 842 depth = gcalls = lockcalls = mpcalls = 0; 843#endif 844 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { 845 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 846 softclock_call_cc(c, cc, 847#ifdef CALLOUT_PROFILING 848 &mpcalls, &lockcalls, &gcalls, 849#endif 850 0); 851#ifdef CALLOUT_PROFILING 852 ++depth; 853#endif 854 } 855#ifdef CALLOUT_PROFILING 856 avg_depth += (depth * 1000 - avg_depth) >> 8; 857 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 858 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 859 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 860#endif 861 } 862} 863 864void 865callout_when(sbintime_t sbt, sbintime_t precision, int flags, 866 sbintime_t *res, sbintime_t *prec_res) 867{ 868 sbintime_t to_sbt, to_pr; 869 870 if ((flags & (C_ABSOLUTE | C_PRECALC)) != 0) { 871 *res = sbt; 872 *prec_res = precision; 873 return; 874 } 875 if ((flags & C_HARDCLOCK) != 0 && sbt < tick_sbt) 876 sbt = tick_sbt; 877 if ((flags & C_HARDCLOCK) != 0 || sbt >= sbt_tickthreshold) { 878 /* 879 * Obtain the time of the last hardclock() call on 880 * this CPU directly from the kern_clocksource.c. 881 * This value is per-CPU, but it is equal for all 882 * active ones. 883 */ 884#ifdef __LP64__ 885 to_sbt = DPCPU_GET(hardclocktime); 886#else 887 spinlock_enter(); 888 to_sbt = DPCPU_GET(hardclocktime); 889 spinlock_exit(); 890#endif 891 if (cold && to_sbt == 0) 892 to_sbt = sbinuptime(); 893 if ((flags & C_HARDCLOCK) == 0) 894 to_sbt += tick_sbt; 895 } else 896 to_sbt = sbinuptime(); 897 if (SBT_MAX - to_sbt < sbt) 898 to_sbt = SBT_MAX; 899 else 900 to_sbt += sbt; 901 *res = to_sbt; 902 to_pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : 903 sbt >> C_PRELGET(flags)); 904 *prec_res = to_pr > precision ? to_pr : precision; 905} 906 907/* 908 * New interface; clients allocate their own callout structures. 909 * 910 * callout_reset() - establish or change a timeout 911 * callout_stop() - disestablish a timeout 912 * callout_init() - initialize a callout structure so that it can 913 * safely be passed to callout_reset() and callout_stop() 914 * 915 * <sys/callout.h> defines three convenience macros: 916 * 917 * callout_active() - returns truth if callout has not been stopped, 918 * drained, or deactivated since the last time the callout was 919 * reset. 920 * callout_pending() - returns truth if callout is still waiting for timeout 921 * callout_deactivate() - marks the callout as having been serviced 922 */ 923int 924callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t prec, 925 callout_func_t *ftn, void *arg, int cpu, int flags) 926{ 927 sbintime_t to_sbt, precision; 928 struct callout_cpu *cc; 929 int cancelled, direct; 930 931 cancelled = 0; 932 callout_when(sbt, prec, flags, &to_sbt, &precision); 933 934 /* 935 * This flag used to be added by callout_cc_add, but the 936 * first time you call this we could end up with the 937 * wrong direct flag if we don't do it before we add. 938 */ 939 if (flags & C_DIRECT_EXEC) { 940 direct = 1; 941 } else { 942 direct = 0; 943 } 944 KASSERT(!direct || c->c_lock == NULL || 945 (LOCK_CLASS(c->c_lock)->lc_flags & LC_SPINLOCK), 946 ("%s: direct callout %p has non-spin lock", __func__, c)); 947 948 cc = callout_lock(c); 949 if (cpu == -1) 950 cpu = c->c_cpu; 951 KASSERT(cpu >= 0 && cpu <= mp_maxid && !CPU_ABSENT(cpu), 952 ("%s: invalid cpu %d", __func__, cpu)); 953 954 if (cc_exec_curr(cc, direct) == c) { 955 /* 956 * We're being asked to reschedule a callout which is 957 * currently in progress. If there is a lock then we 958 * can cancel the callout if it has not really started. 959 */ 960 if (c->c_lock != NULL && !cc_exec_cancel(cc, direct)) 961 cancelled = cc_exec_cancel(cc, direct) = true; 962 if (cc_exec_waiting(cc, direct)) { 963 /* 964 * Someone has called callout_drain to kill this 965 * callout. Don't reschedule. 966 */ 967 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 968 cancelled ? "cancelled" : "failed to cancel", 969 c, c->c_func, c->c_arg); 970 CC_UNLOCK(cc); 971 return (cancelled); 972 } 973#ifdef SMP 974 if (callout_migrating(c)) { 975 /* 976 * This only occurs when a second callout_reset_sbt_on 977 * is made after a previous one moved it into 978 * deferred migration (below). Note we do *not* change 979 * the prev_cpu even though the previous target may 980 * be different. 981 */ 982 cc_migration_cpu(cc, direct) = cpu; 983 cc_migration_time(cc, direct) = to_sbt; 984 cc_migration_prec(cc, direct) = precision; 985 cc_migration_func(cc, direct) = ftn; 986 cc_migration_arg(cc, direct) = arg; 987 cancelled = 1; 988 CC_UNLOCK(cc); 989 return (cancelled); 990 } 991#endif 992 } 993 if (c->c_iflags & CALLOUT_PENDING) { 994 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 995 if (cc_exec_next(cc) == c) 996 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 997 LIST_REMOVE(c, c_links.le); 998 } else { 999 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1000 } 1001 cancelled = 1; 1002 c->c_iflags &= ~ CALLOUT_PENDING; 1003 c->c_flags &= ~ CALLOUT_ACTIVE; 1004 } 1005 1006#ifdef SMP 1007 /* 1008 * If the callout must migrate try to perform it immediately. 1009 * If the callout is currently running, just defer the migration 1010 * to a more appropriate moment. 1011 */ 1012 if (c->c_cpu != cpu) { 1013 if (cc_exec_curr(cc, direct) == c) { 1014 /* 1015 * Pending will have been removed since we are 1016 * actually executing the callout on another 1017 * CPU. That callout should be waiting on the 1018 * lock the caller holds. If we set both 1019 * active/and/pending after we return and the 1020 * lock on the executing callout proceeds, it 1021 * will then see pending is true and return. 1022 * At the return from the actual callout execution 1023 * the migration will occur in softclock_call_cc 1024 * and this new callout will be placed on the 1025 * new CPU via a call to callout_cpu_switch() which 1026 * will get the lock on the right CPU followed 1027 * by a call callout_cc_add() which will add it there. 1028 * (see above in softclock_call_cc()). 1029 */ 1030 cc_migration_cpu(cc, direct) = cpu; 1031 cc_migration_time(cc, direct) = to_sbt; 1032 cc_migration_prec(cc, direct) = precision; 1033 cc_migration_func(cc, direct) = ftn; 1034 cc_migration_arg(cc, direct) = arg; 1035 c->c_iflags |= (CALLOUT_DFRMIGRATION | CALLOUT_PENDING); 1036 c->c_flags |= CALLOUT_ACTIVE; 1037 CTR6(KTR_CALLOUT, 1038 "migration of %p func %p arg %p in %d.%08x to %u deferred", 1039 c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1040 (u_int)(to_sbt & 0xffffffff), cpu); 1041 CC_UNLOCK(cc); 1042 return (cancelled); 1043 } 1044 cc = callout_cpu_switch(c, cc, cpu); 1045 } 1046#endif 1047 1048 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, flags); 1049 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", 1050 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1051 (u_int)(to_sbt & 0xffffffff)); 1052 CC_UNLOCK(cc); 1053 1054 return (cancelled); 1055} 1056 1057/* 1058 * Common idioms that can be optimized in the future. 1059 */ 1060int 1061callout_schedule_on(struct callout *c, int to_ticks, int cpu) 1062{ 1063 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 1064} 1065 1066int 1067callout_schedule(struct callout *c, int to_ticks) 1068{ 1069 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 1070} 1071 1072int 1073_callout_stop_safe(struct callout *c, int flags) 1074{ 1075 struct callout_cpu *cc, *old_cc; 1076 struct lock_class *class; 1077 int direct, sq_locked, use_lock; 1078 int cancelled, not_on_a_list; 1079 1080 if ((flags & CS_DRAIN) != 0) 1081 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock, 1082 "calling %s", __func__); 1083 1084 /* 1085 * Some old subsystems don't hold Giant while running a callout_stop(), 1086 * so just discard this check for the moment. 1087 */ 1088 if ((flags & CS_DRAIN) == 0 && c->c_lock != NULL) { 1089 if (c->c_lock == &Giant.lock_object) 1090 use_lock = mtx_owned(&Giant); 1091 else { 1092 use_lock = 1; 1093 class = LOCK_CLASS(c->c_lock); 1094 class->lc_assert(c->c_lock, LA_XLOCKED); 1095 } 1096 } else 1097 use_lock = 0; 1098 if (c->c_iflags & CALLOUT_DIRECT) { 1099 direct = 1; 1100 } else { 1101 direct = 0; 1102 } 1103 sq_locked = 0; 1104 old_cc = NULL; 1105again: 1106 cc = callout_lock(c); 1107 1108 if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) == 1109 (CALLOUT_DFRMIGRATION | CALLOUT_PENDING) && 1110 ((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) { 1111 /* 1112 * Special case where this slipped in while we 1113 * were migrating *as* the callout is about to 1114 * execute. The caller probably holds the lock 1115 * the callout wants. 1116 * 1117 * Get rid of the migration first. Then set 1118 * the flag that tells this code *not* to 1119 * try to remove it from any lists (its not 1120 * on one yet). When the callout wheel runs, 1121 * it will ignore this callout. 1122 */ 1123 c->c_iflags &= ~CALLOUT_PENDING; 1124 c->c_flags &= ~CALLOUT_ACTIVE; 1125 not_on_a_list = 1; 1126 } else { 1127 not_on_a_list = 0; 1128 } 1129 1130 /* 1131 * If the callout was migrating while the callout cpu lock was 1132 * dropped, just drop the sleepqueue lock and check the states 1133 * again. 1134 */ 1135 if (sq_locked != 0 && cc != old_cc) { 1136#ifdef SMP 1137 CC_UNLOCK(cc); 1138 sleepq_release(&cc_exec_waiting(old_cc, direct)); 1139 sq_locked = 0; 1140 old_cc = NULL; 1141 goto again; 1142#else 1143 panic("migration should not happen"); 1144#endif 1145 } 1146 1147 /* 1148 * If the callout is running, try to stop it or drain it. 1149 */ 1150 if (cc_exec_curr(cc, direct) == c) { 1151 /* 1152 * Succeed we to stop it or not, we must clear the 1153 * active flag - this is what API users expect. If we're 1154 * draining and the callout is currently executing, first wait 1155 * until it finishes. 1156 */ 1157 if ((flags & CS_DRAIN) == 0) 1158 c->c_flags &= ~CALLOUT_ACTIVE; 1159 1160 if ((flags & CS_DRAIN) != 0) { 1161 /* 1162 * The current callout is running (or just 1163 * about to run) and blocking is allowed, so 1164 * just wait for the current invocation to 1165 * finish. 1166 */ 1167 if (cc_exec_curr(cc, direct) == c) { 1168 /* 1169 * Use direct calls to sleepqueue interface 1170 * instead of cv/msleep in order to avoid 1171 * a LOR between cc_lock and sleepqueue 1172 * chain spinlocks. This piece of code 1173 * emulates a msleep_spin() call actually. 1174 * 1175 * If we already have the sleepqueue chain 1176 * locked, then we can safely block. If we 1177 * don't already have it locked, however, 1178 * we have to drop the cc_lock to lock 1179 * it. This opens several races, so we 1180 * restart at the beginning once we have 1181 * both locks. If nothing has changed, then 1182 * we will end up back here with sq_locked 1183 * set. 1184 */ 1185 if (!sq_locked) { 1186 CC_UNLOCK(cc); 1187 sleepq_lock( 1188 &cc_exec_waiting(cc, direct)); 1189 sq_locked = 1; 1190 old_cc = cc; 1191 goto again; 1192 } 1193 1194 /* 1195 * Migration could be cancelled here, but 1196 * as long as it is still not sure when it 1197 * will be packed up, just let softclock() 1198 * take care of it. 1199 */ 1200 cc_exec_waiting(cc, direct) = true; 1201 DROP_GIANT(); 1202 CC_UNLOCK(cc); 1203 sleepq_add( 1204 &cc_exec_waiting(cc, direct), 1205 &cc->cc_lock.lock_object, "codrain", 1206 SLEEPQ_SLEEP, 0); 1207 sleepq_wait( 1208 &cc_exec_waiting(cc, direct), 1209 0); 1210 sq_locked = 0; 1211 old_cc = NULL; 1212 1213 /* Reacquire locks previously released. */ 1214 PICKUP_GIANT(); 1215 goto again; 1216 } 1217 c->c_flags &= ~CALLOUT_ACTIVE; 1218 } else if (use_lock && !cc_exec_cancel(cc, direct)) { 1219 1220 /* 1221 * The current callout is waiting for its 1222 * lock which we hold. Cancel the callout 1223 * and return. After our caller drops the 1224 * lock, the callout will be skipped in 1225 * softclock(). This *only* works with a 1226 * callout_stop() *not* with callout_drain(). 1227 */ 1228 cc_exec_cancel(cc, direct) = true; 1229 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1230 c, c->c_func, c->c_arg); 1231 KASSERT(!cc_cce_migrating(cc, direct), 1232 ("callout wrongly scheduled for migration")); 1233 if (callout_migrating(c)) { 1234 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1235#ifdef SMP 1236 cc_migration_cpu(cc, direct) = CPUBLOCK; 1237 cc_migration_time(cc, direct) = 0; 1238 cc_migration_prec(cc, direct) = 0; 1239 cc_migration_func(cc, direct) = NULL; 1240 cc_migration_arg(cc, direct) = NULL; 1241#endif 1242 } 1243 CC_UNLOCK(cc); 1244 KASSERT(!sq_locked, ("sleepqueue chain locked")); 1245 return (1); 1246 } else if (callout_migrating(c)) { 1247 /* 1248 * The callout is currently being serviced 1249 * and the "next" callout is scheduled at 1250 * its completion with a migration. We remove 1251 * the migration flag so it *won't* get rescheduled, 1252 * but we can't stop the one thats running so 1253 * we return 0. 1254 */ 1255 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1256#ifdef SMP 1257 /* 1258 * We can't call cc_cce_cleanup here since 1259 * if we do it will remove .ce_curr and 1260 * its still running. This will prevent a 1261 * reschedule of the callout when the 1262 * execution completes. 1263 */ 1264 cc_migration_cpu(cc, direct) = CPUBLOCK; 1265 cc_migration_time(cc, direct) = 0; 1266 cc_migration_prec(cc, direct) = 0; 1267 cc_migration_func(cc, direct) = NULL; 1268 cc_migration_arg(cc, direct) = NULL; 1269#endif 1270 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 1271 c, c->c_func, c->c_arg); 1272 CC_UNLOCK(cc); 1273 return (0); 1274 } else { 1275 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1276 c, c->c_func, c->c_arg); 1277 } 1278 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 1279 cancelled = 0; 1280 } else 1281 cancelled = 1; 1282 1283 if (sq_locked) 1284 sleepq_release(&cc_exec_waiting(cc, direct)); 1285 1286 if ((c->c_iflags & CALLOUT_PENDING) == 0) { 1287 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1288 c, c->c_func, c->c_arg); 1289 /* 1290 * For not scheduled and not executing callout return 1291 * negative value. 1292 */ 1293 if (cc_exec_curr(cc, direct) != c) 1294 cancelled = -1; 1295 CC_UNLOCK(cc); 1296 return (cancelled); 1297 } 1298 1299 c->c_iflags &= ~CALLOUT_PENDING; 1300 c->c_flags &= ~CALLOUT_ACTIVE; 1301 1302 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1303 c, c->c_func, c->c_arg); 1304 if (not_on_a_list == 0) { 1305 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1306 if (cc_exec_next(cc) == c) 1307 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1308 LIST_REMOVE(c, c_links.le); 1309 } else { 1310 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1311 } 1312 } 1313 CC_UNLOCK(cc); 1314 return (cancelled); 1315} 1316 1317void 1318callout_init(struct callout *c, int mpsafe) 1319{ 1320 bzero(c, sizeof *c); 1321 if (mpsafe) { 1322 c->c_lock = NULL; 1323 c->c_iflags = CALLOUT_RETURNUNLOCKED; 1324 } else { 1325 c->c_lock = &Giant.lock_object; 1326 c->c_iflags = 0; 1327 } 1328 c->c_cpu = cc_default_cpu; 1329} 1330 1331void 1332_callout_init_lock(struct callout *c, struct lock_object *lock, int flags) 1333{ 1334 bzero(c, sizeof *c); 1335 c->c_lock = lock; 1336 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1337 ("callout_init_lock: bad flags %d", flags)); 1338 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1339 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1340 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & LC_SLEEPABLE), 1341 ("%s: callout %p has sleepable lock", __func__, c)); 1342 c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1343 c->c_cpu = cc_default_cpu; 1344} 1345 1346static int 1347flssbt(sbintime_t sbt) 1348{ 1349 1350 sbt += (uint64_t)sbt >> 1; 1351 if (sizeof(long) >= sizeof(sbintime_t)) 1352 return (flsl(sbt)); 1353 if (sbt >= SBT_1S) 1354 return (flsl(((uint64_t)sbt) >> 32) + 32); 1355 return (flsl(sbt)); 1356} 1357 1358/* 1359 * Dump immediate statistic snapshot of the scheduled callouts. 1360 */ 1361static int 1362sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1363{ 1364 struct callout *tmp; 1365 struct callout_cpu *cc; 1366 struct callout_list *sc; 1367 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; 1368 int ct[64], cpr[64], ccpbk[32]; 1369 int error, val, i, count, tcum, pcum, maxc, c, medc; 1370 int cpu; 1371 1372 val = 0; 1373 error = sysctl_handle_int(oidp, &val, 0, req); 1374 if (error != 0 || req->newptr == NULL) 1375 return (error); 1376 count = maxc = 0; 1377 st = spr = maxt = maxpr = 0; 1378 bzero(ccpbk, sizeof(ccpbk)); 1379 bzero(ct, sizeof(ct)); 1380 bzero(cpr, sizeof(cpr)); 1381 now = sbinuptime(); 1382 CPU_FOREACH(cpu) { 1383 cc = CC_CPU(cpu); 1384 CC_LOCK(cc); 1385 for (i = 0; i < callwheelsize; i++) { 1386 sc = &cc->cc_callwheel[i]; 1387 c = 0; 1388 LIST_FOREACH(tmp, sc, c_links.le) { 1389 c++; 1390 t = tmp->c_time - now; 1391 if (t < 0) 1392 t = 0; 1393 st += t / SBT_1US; 1394 spr += tmp->c_precision / SBT_1US; 1395 if (t > maxt) 1396 maxt = t; 1397 if (tmp->c_precision > maxpr) 1398 maxpr = tmp->c_precision; 1399 ct[flssbt(t)]++; 1400 cpr[flssbt(tmp->c_precision)]++; 1401 } 1402 if (c > maxc) 1403 maxc = c; 1404 ccpbk[fls(c + c / 2)]++; 1405 count += c; 1406 } 1407 CC_UNLOCK(cc); 1408 } 1409 1410 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1411 tcum += ct[i]; 1412 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1413 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) 1414 pcum += cpr[i]; 1415 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1416 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1417 c += ccpbk[i]; 1418 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1419 1420 printf("Scheduled callouts statistic snapshot:\n"); 1421 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1422 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1423 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1424 medc, 1425 count / callwheelsize / mp_ncpus, 1426 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1427 maxc); 1428 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1429 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1430 (st / count) / 1000000, (st / count) % 1000000, 1431 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); 1432 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1433 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, 1434 (spr / count) / 1000000, (spr / count) % 1000000, 1435 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); 1436 printf(" Distribution: \tbuckets\t time\t tcum\t" 1437 " prec\t pcum\n"); 1438 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1439 if (ct[i] == 0 && cpr[i] == 0) 1440 continue; 1441 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1442 tcum += ct[i]; 1443 pcum += cpr[i]; 1444 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", 1445 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1446 i - 1 - (32 - CC_HASH_SHIFT), 1447 ct[i], tcum, cpr[i], pcum); 1448 } 1449 return (error); 1450} 1451SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1452 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1453 0, 0, sysctl_kern_callout_stat, "I", 1454 "Dump immediate statistic snapshot of the scheduled callouts"); 1455 1456#ifdef DDB 1457static void 1458_show_callout(struct callout *c) 1459{ 1460 1461 db_printf("callout %p\n", c); 1462#define C_DB_PRINTF(f, e) db_printf(" %s = " f "\n", #e, c->e); 1463 db_printf(" &c_links = %p\n", &(c->c_links)); 1464 C_DB_PRINTF("%" PRId64, c_time); 1465 C_DB_PRINTF("%" PRId64, c_precision); 1466 C_DB_PRINTF("%p", c_arg); 1467 C_DB_PRINTF("%p", c_func); 1468 C_DB_PRINTF("%p", c_lock); 1469 C_DB_PRINTF("%#x", c_flags); 1470 C_DB_PRINTF("%#x", c_iflags); 1471 C_DB_PRINTF("%d", c_cpu); 1472#undef C_DB_PRINTF 1473} 1474 1475DB_SHOW_COMMAND(callout, db_show_callout) 1476{ 1477 1478 if (!have_addr) { 1479 db_printf("usage: show callout <struct callout *>\n"); 1480 return; 1481 } 1482 1483 _show_callout((struct callout *)addr); 1484} 1485 1486static void 1487_show_last_callout(int cpu, int direct, const char *dirstr) 1488{ 1489 struct callout_cpu *cc; 1490 void *func, *arg; 1491 1492 cc = CC_CPU(cpu); 1493 func = cc_exec_last_func(cc, direct); 1494 arg = cc_exec_last_arg(cc, direct); 1495 db_printf("cpu %d last%s callout function: %p ", cpu, dirstr, func); 1496 db_printsym((db_expr_t)func, DB_STGY_ANY); 1497 db_printf("\ncpu %d last%s callout argument: %p\n", cpu, dirstr, arg); 1498} 1499 1500DB_SHOW_COMMAND_FLAGS(callout_last, db_show_callout_last, DB_CMD_MEMSAFE) 1501{ 1502 int cpu, last; 1503 1504 if (have_addr) { 1505 if (addr < 0 || addr > mp_maxid || CPU_ABSENT(addr)) { 1506 db_printf("no such cpu: %d\n", (int)addr); 1507 return; 1508 } 1509 cpu = last = addr; 1510 } else { 1511 cpu = 0; 1512 last = mp_maxid; 1513 } 1514 1515 while (cpu <= last) { 1516 if (!CPU_ABSENT(cpu)) { 1517 _show_last_callout(cpu, 0, ""); 1518 _show_last_callout(cpu, 1, " direct"); 1519 } 1520 cpu++; 1521 } 1522} 1523#endif /* DDB */ 1524