Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/kern/kern_timeout.c
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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 * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include "opt_callout_profiling.h" 43 #include "opt_ddb.h" 44 #include "opt_rss.h" 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/bus.h> 49 #include <sys/callout.h> 50 #include <sys/domainset.h> 51 #include <sys/file.h> 52 #include <sys/interrupt.h> 53 #include <sys/kernel.h> 54 #include <sys/ktr.h> 55 #include <sys/lock.h> 56 #include <sys/malloc.h> 57 #include <sys/mutex.h> 58 #include <sys/proc.h> 59 #include <sys/sdt.h> 60 #include <sys/sleepqueue.h> 61 #include <sys/sysctl.h> 62 #include <sys/smp.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 74 DPCPU_DECLARE(sbintime_t, hardclocktime); 75 76 SDT_PROVIDER_DEFINE(callout_execute); 77 SDT_PROBE_DEFINE1(callout_execute, , , callout__start, "struct callout *"); 78 SDT_PROBE_DEFINE1(callout_execute, , , callout__end, "struct callout *"); 79 80 #ifdef CALLOUT_PROFILING 81 static int avg_depth; 82 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, 83 "Average number of items examined per softclock call. Units = 1/1000"); 84 static int avg_gcalls; 85 SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, 86 "Average number of Giant callouts made per softclock call. Units = 1/1000"); 87 static int avg_lockcalls; 88 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0, 89 "Average number of lock callouts made per softclock call. Units = 1/1000"); 90 static int avg_mpcalls; 91 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, 92 "Average number of MP callouts made per softclock call. Units = 1/1000"); 93 static int avg_depth_dir; 94 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0, 95 "Average number of direct callouts examined per callout_process call. " 96 "Units = 1/1000"); 97 static int avg_lockcalls_dir; 98 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD, 99 &avg_lockcalls_dir, 0, "Average number of lock direct callouts made per " 100 "callout_process call. Units = 1/1000"); 101 static int avg_mpcalls_dir; 102 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir, 103 0, "Average number of MP direct callouts made per callout_process call. " 104 "Units = 1/1000"); 105 #endif 106 107 static int ncallout; 108 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &ncallout, 0, 109 "Number of entries in callwheel and size of timeout() preallocation"); 110 111 #ifdef RSS 112 static int pin_default_swi = 1; 113 static int pin_pcpu_swi = 1; 114 #else 115 static int pin_default_swi = 0; 116 static int pin_pcpu_swi = 0; 117 #endif 118 119 SYSCTL_INT(_kern, OID_AUTO, pin_default_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_default_swi, 120 0, "Pin the default (non-per-cpu) swi (shared with PCPU 0 swi)"); 121 SYSCTL_INT(_kern, OID_AUTO, pin_pcpu_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_pcpu_swi, 122 0, "Pin the per-CPU swis (except PCPU 0, which is also default)"); 123 124 /* 125 * TODO: 126 * allocate more timeout table slots when table overflows. 127 */ 128 static u_int __read_mostly callwheelsize; 129 static u_int __read_mostly callwheelmask; 130 131 /* 132 * The callout cpu exec entities represent informations necessary for 133 * describing the state of callouts currently running on the CPU and the ones 134 * necessary for migrating callouts to the new callout cpu. In particular, 135 * the first entry of the array cc_exec_entity holds informations for callout 136 * running in SWI thread context, while the second one holds informations 137 * for callout running directly from hardware interrupt context. 138 * The cached informations are very important for deferring migration when 139 * the migrating callout is already running. 140 */ 141 struct cc_exec { 142 struct callout *cc_curr; 143 callout_func_t *cc_drain; 144 void *cc_last_func; 145 void *cc_last_arg; 146 #ifdef SMP 147 callout_func_t *ce_migration_func; 148 void *ce_migration_arg; 149 sbintime_t ce_migration_time; 150 sbintime_t ce_migration_prec; 151 int ce_migration_cpu; 152 #endif 153 bool cc_cancel; 154 bool cc_waiting; 155 }; 156 157 /* 158 * There is one struct callout_cpu per cpu, holding all relevant 159 * state for the callout processing thread on the individual CPU. 160 */ 161 struct callout_cpu { 162 struct mtx_padalign cc_lock; 163 struct cc_exec cc_exec_entity[2]; 164 struct callout *cc_next; 165 struct callout_list *cc_callwheel; 166 struct callout_tailq cc_expireq; 167 sbintime_t cc_firstevent; 168 sbintime_t cc_lastscan; 169 void *cc_cookie; 170 u_int cc_bucket; 171 u_int cc_inited; 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_drain(cc, dir) cc->cc_exec_entity[dir].cc_drain 183 #define cc_exec_next(cc) cc->cc_next 184 #define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel 185 #define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting 186 #ifdef SMP 187 #define cc_migration_func(cc, dir) cc->cc_exec_entity[dir].ce_migration_func 188 #define cc_migration_arg(cc, dir) cc->cc_exec_entity[dir].ce_migration_arg 189 #define cc_migration_cpu(cc, dir) cc->cc_exec_entity[dir].ce_migration_cpu 190 #define cc_migration_time(cc, dir) cc->cc_exec_entity[dir].ce_migration_time 191 #define cc_migration_prec(cc, dir) cc->cc_exec_entity[dir].ce_migration_prec 192 193 static struct callout_cpu cc_cpu[MAXCPU]; 194 #define CPUBLOCK MAXCPU 195 #define CC_CPU(cpu) (&cc_cpu[(cpu)]) 196 #define CC_SELF() CC_CPU(PCPU_GET(cpuid)) 197 #else 198 static struct callout_cpu cc_cpu; 199 #define CC_CPU(cpu) (&cc_cpu) 200 #define CC_SELF() (&cc_cpu) 201 #endif 202 #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) 203 #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) 204 #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) 205 206 static int __read_mostly cc_default_cpu; 207 208 static void callout_cpu_init(struct callout_cpu *cc, int cpu); 209 static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, 210 #ifdef CALLOUT_PROFILING 211 int *mpcalls, int *lockcalls, int *gcalls, 212 #endif 213 int direct); 214 215 static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); 216 217 /** 218 * Locked by cc_lock: 219 * cc_curr - If a callout is in progress, it is cc_curr. 220 * If cc_curr is non-NULL, threads waiting in 221 * callout_drain() will be woken up as soon as the 222 * relevant callout completes. 223 * cc_cancel - Changing to 1 with both callout_lock and cc_lock held 224 * guarantees that the current callout will not run. 225 * The softclock() function sets this to 0 before it 226 * drops callout_lock to acquire c_lock, and it calls 227 * the handler only if curr_cancelled is still 0 after 228 * cc_lock is successfully acquired. 229 * cc_waiting - If a thread is waiting in callout_drain(), then 230 * callout_wait is nonzero. Set only when 231 * cc_curr is non-NULL. 232 */ 233 234 /* 235 * Resets the execution entity tied to a specific callout cpu. 236 */ 237 static void 238 cc_cce_cleanup(struct callout_cpu *cc, int direct) 239 { 240 241 cc_exec_curr(cc, direct) = NULL; 242 cc_exec_cancel(cc, direct) = false; 243 cc_exec_waiting(cc, direct) = false; 244 #ifdef SMP 245 cc_migration_cpu(cc, direct) = CPUBLOCK; 246 cc_migration_time(cc, direct) = 0; 247 cc_migration_prec(cc, direct) = 0; 248 cc_migration_func(cc, direct) = NULL; 249 cc_migration_arg(cc, direct) = NULL; 250 #endif 251 } 252 253 /* 254 * Checks if migration is requested by a specific callout cpu. 255 */ 256 static int 257 cc_cce_migrating(struct callout_cpu *cc, int direct) 258 { 259 260 #ifdef SMP 261 return (cc_migration_cpu(cc, direct) != CPUBLOCK); 262 #else 263 return (0); 264 #endif 265 } 266 267 /* 268 * Kernel low level callwheel initialization 269 * called on the BSP during kernel startup. 270 */ 271 static void 272 callout_callwheel_init(void *dummy) 273 { 274 struct callout_cpu *cc; 275 int cpu; 276 277 /* 278 * Calculate the size of the callout wheel and the preallocated 279 * timeout() structures. 280 * XXX: Clip callout to result of previous function of maxusers 281 * maximum 384. This is still huge, but acceptable. 282 */ 283 ncallout = imin(16 + maxproc + maxfiles, 18508); 284 TUNABLE_INT_FETCH("kern.ncallout", &ncallout); 285 286 /* 287 * Calculate callout wheel size, should be next power of two higher 288 * than 'ncallout'. 289 */ 290 callwheelsize = 1 << fls(ncallout); 291 callwheelmask = callwheelsize - 1; 292 293 /* 294 * Fetch whether we're pinning the swi's or not. 295 */ 296 TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi); 297 TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi); 298 299 /* 300 * Initialize callout wheels. The software interrupt threads 301 * are created later. 302 */ 303 cc_default_cpu = PCPU_GET(cpuid); 304 CPU_FOREACH(cpu) { 305 cc = CC_CPU(cpu); 306 callout_cpu_init(cc, cpu); 307 } 308 } 309 SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); 310 311 /* 312 * Initialize the per-cpu callout structures. 313 */ 314 static void 315 callout_cpu_init(struct callout_cpu *cc, int cpu) 316 { 317 int i; 318 319 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); 320 cc->cc_inited = 1; 321 cc->cc_callwheel = malloc_domainset(sizeof(struct callout_list) * 322 callwheelsize, M_CALLOUT, 323 DOMAINSET_PREF(pcpu_find(cpu)->pc_domain), M_WAITOK); 324 for (i = 0; i < callwheelsize; i++) 325 LIST_INIT(&cc->cc_callwheel[i]); 326 TAILQ_INIT(&cc->cc_expireq); 327 cc->cc_firstevent = SBT_MAX; 328 for (i = 0; i < 2; i++) 329 cc_cce_cleanup(cc, i); 330 #ifdef KTR 331 snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name), 332 "callwheel cpu %d", cpu); 333 #endif 334 } 335 336 #ifdef SMP 337 /* 338 * Switches the cpu tied to a specific callout. 339 * The function expects a locked incoming callout cpu and returns with 340 * locked outcoming callout cpu. 341 */ 342 static struct callout_cpu * 343 callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu) 344 { 345 struct callout_cpu *new_cc; 346 347 MPASS(c != NULL && cc != NULL); 348 CC_LOCK_ASSERT(cc); 349 350 /* 351 * Avoid interrupts and preemption firing after the callout cpu 352 * is blocked in order to avoid deadlocks as the new thread 353 * may be willing to acquire the callout cpu lock. 354 */ 355 c->c_cpu = CPUBLOCK; 356 spinlock_enter(); 357 CC_UNLOCK(cc); 358 new_cc = CC_CPU(new_cpu); 359 CC_LOCK(new_cc); 360 spinlock_exit(); 361 c->c_cpu = new_cpu; 362 return (new_cc); 363 } 364 #endif 365 366 /* 367 * Start softclock threads. 368 */ 369 static void 370 start_softclock(void *dummy) 371 { 372 struct callout_cpu *cc; 373 char name[MAXCOMLEN]; 374 int cpu; 375 bool pin_swi; 376 struct intr_event *ie; 377 378 CPU_FOREACH(cpu) { 379 cc = CC_CPU(cpu); 380 snprintf(name, sizeof(name), "clock (%d)", cpu); 381 ie = NULL; 382 if (swi_add(&ie, name, softclock, cc, SWI_CLOCK, 383 INTR_MPSAFE, &cc->cc_cookie)) 384 panic("died while creating standard software ithreads"); 385 if (cpu == cc_default_cpu) 386 pin_swi = pin_default_swi; 387 else 388 pin_swi = pin_pcpu_swi; 389 if (pin_swi && (intr_event_bind(ie, cpu) != 0)) { 390 printf("%s: %s clock couldn't be pinned to cpu %d\n", 391 __func__, 392 cpu == cc_default_cpu ? "default" : "per-cpu", 393 cpu); 394 } 395 } 396 } 397 SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); 398 399 #define CC_HASH_SHIFT 8 400 401 static inline u_int 402 callout_hash(sbintime_t sbt) 403 { 404 405 return (sbt >> (32 - CC_HASH_SHIFT)); 406 } 407 408 static inline u_int 409 callout_get_bucket(sbintime_t sbt) 410 { 411 412 return (callout_hash(sbt) & callwheelmask); 413 } 414 415 void 416 callout_process(sbintime_t now) 417 { 418 struct callout *tmp, *tmpn; 419 struct callout_cpu *cc; 420 struct callout_list *sc; 421 sbintime_t first, last, max, tmp_max; 422 uint32_t lookahead; 423 u_int firstb, lastb, nowb; 424 #ifdef CALLOUT_PROFILING 425 int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0; 426 #endif 427 428 cc = CC_SELF(); 429 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET); 430 431 /* Compute the buckets of the last scan and present times. */ 432 firstb = callout_hash(cc->cc_lastscan); 433 cc->cc_lastscan = now; 434 nowb = callout_hash(now); 435 436 /* Compute the last bucket and minimum time of the bucket after it. */ 437 if (nowb == firstb) 438 lookahead = (SBT_1S / 16); 439 else if (nowb - firstb == 1) 440 lookahead = (SBT_1S / 8); 441 else 442 lookahead = (SBT_1S / 2); 443 first = last = now; 444 first += (lookahead / 2); 445 last += lookahead; 446 last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); 447 lastb = callout_hash(last) - 1; 448 max = last; 449 450 /* 451 * Check if we wrapped around the entire wheel from the last scan. 452 * In case, we need to scan entirely the wheel for pending callouts. 453 */ 454 if (lastb - firstb >= callwheelsize) { 455 lastb = firstb + callwheelsize - 1; 456 if (nowb - firstb >= callwheelsize) 457 nowb = lastb; 458 } 459 460 /* Iterate callwheel from firstb to nowb and then up to lastb. */ 461 do { 462 sc = &cc->cc_callwheel[firstb & callwheelmask]; 463 tmp = LIST_FIRST(sc); 464 while (tmp != NULL) { 465 /* Run the callout if present time within allowed. */ 466 if (tmp->c_time <= now) { 467 /* 468 * Consumer told us the callout may be run 469 * directly from hardware interrupt context. 470 */ 471 if (tmp->c_iflags & CALLOUT_DIRECT) { 472 #ifdef CALLOUT_PROFILING 473 ++depth_dir; 474 #endif 475 cc_exec_next(cc) = 476 LIST_NEXT(tmp, c_links.le); 477 cc->cc_bucket = firstb & callwheelmask; 478 LIST_REMOVE(tmp, c_links.le); 479 softclock_call_cc(tmp, cc, 480 #ifdef CALLOUT_PROFILING 481 &mpcalls_dir, &lockcalls_dir, NULL, 482 #endif 483 1); 484 tmp = cc_exec_next(cc); 485 cc_exec_next(cc) = NULL; 486 } else { 487 tmpn = LIST_NEXT(tmp, c_links.le); 488 LIST_REMOVE(tmp, c_links.le); 489 TAILQ_INSERT_TAIL(&cc->cc_expireq, 490 tmp, c_links.tqe); 491 tmp->c_iflags |= CALLOUT_PROCESSED; 492 tmp = tmpn; 493 } 494 continue; 495 } 496 /* Skip events from distant future. */ 497 if (tmp->c_time >= max) 498 goto next; 499 /* 500 * Event minimal time is bigger than present maximal 501 * time, so it cannot be aggregated. 502 */ 503 if (tmp->c_time > last) { 504 lastb = nowb; 505 goto next; 506 } 507 /* Update first and last time, respecting this event. */ 508 if (tmp->c_time < first) 509 first = tmp->c_time; 510 tmp_max = tmp->c_time + tmp->c_precision; 511 if (tmp_max < last) 512 last = tmp_max; 513 next: 514 tmp = LIST_NEXT(tmp, c_links.le); 515 } 516 /* Proceed with the next bucket. */ 517 firstb++; 518 /* 519 * Stop if we looked after present time and found 520 * some event we can't execute at now. 521 * Stop if we looked far enough into the future. 522 */ 523 } while (((int)(firstb - lastb)) <= 0); 524 cc->cc_firstevent = last; 525 cpu_new_callout(curcpu, last, first); 526 527 #ifdef CALLOUT_PROFILING 528 avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8; 529 avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8; 530 avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8; 531 #endif 532 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 533 /* 534 * swi_sched acquires the thread lock, so we don't want to call it 535 * with cc_lock held; incorrect locking order. 536 */ 537 if (!TAILQ_EMPTY(&cc->cc_expireq)) 538 swi_sched(cc->cc_cookie, 0); 539 } 540 541 static struct callout_cpu * 542 callout_lock(struct callout *c) 543 { 544 struct callout_cpu *cc; 545 int cpu; 546 547 for (;;) { 548 cpu = c->c_cpu; 549 #ifdef SMP 550 if (cpu == CPUBLOCK) { 551 while (c->c_cpu == CPUBLOCK) 552 cpu_spinwait(); 553 continue; 554 } 555 #endif 556 cc = CC_CPU(cpu); 557 CC_LOCK(cc); 558 if (cpu == c->c_cpu) 559 break; 560 CC_UNLOCK(cc); 561 } 562 return (cc); 563 } 564 565 static void 566 callout_cc_add(struct callout *c, struct callout_cpu *cc, 567 sbintime_t sbt, sbintime_t precision, void (*func)(void *), 568 void *arg, int cpu, int flags) 569 { 570 int bucket; 571 572 CC_LOCK_ASSERT(cc); 573 if (sbt < cc->cc_lastscan) 574 sbt = cc->cc_lastscan; 575 c->c_arg = arg; 576 c->c_iflags |= CALLOUT_PENDING; 577 c->c_iflags &= ~CALLOUT_PROCESSED; 578 c->c_flags |= CALLOUT_ACTIVE; 579 if (flags & C_DIRECT_EXEC) 580 c->c_iflags |= CALLOUT_DIRECT; 581 c->c_func = func; 582 c->c_time = sbt; 583 c->c_precision = precision; 584 bucket = callout_get_bucket(c->c_time); 585 CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x", 586 c, (int)(c->c_precision >> 32), 587 (u_int)(c->c_precision & 0xffffffff)); 588 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); 589 if (cc->cc_bucket == bucket) 590 cc_exec_next(cc) = c; 591 592 /* 593 * Inform the eventtimers(4) subsystem there's a new callout 594 * that has been inserted, but only if really required. 595 */ 596 if (SBT_MAX - c->c_time < c->c_precision) 597 c->c_precision = SBT_MAX - c->c_time; 598 sbt = c->c_time + c->c_precision; 599 if (sbt < cc->cc_firstevent) { 600 cc->cc_firstevent = sbt; 601 cpu_new_callout(cpu, sbt, c->c_time); 602 } 603 } 604 605 static void 606 softclock_call_cc(struct callout *c, struct callout_cpu *cc, 607 #ifdef CALLOUT_PROFILING 608 int *mpcalls, int *lockcalls, int *gcalls, 609 #endif 610 int direct) 611 { 612 struct rm_priotracker tracker; 613 callout_func_t *c_func, *drain; 614 void *c_arg; 615 struct lock_class *class; 616 struct lock_object *c_lock; 617 uintptr_t lock_status; 618 int c_iflags; 619 #ifdef SMP 620 struct callout_cpu *new_cc; 621 callout_func_t *new_func; 622 void *new_arg; 623 int flags, new_cpu; 624 sbintime_t new_prec, new_time; 625 #endif 626 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 627 sbintime_t sbt1, sbt2; 628 struct timespec ts2; 629 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 630 static callout_func_t *lastfunc; 631 #endif 632 633 KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING, 634 ("softclock_call_cc: pend %p %x", c, c->c_iflags)); 635 KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE, 636 ("softclock_call_cc: act %p %x", c, c->c_flags)); 637 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; 638 lock_status = 0; 639 if (c->c_flags & CALLOUT_SHAREDLOCK) { 640 if (class == &lock_class_rm) 641 lock_status = (uintptr_t)&tracker; 642 else 643 lock_status = 1; 644 } 645 c_lock = c->c_lock; 646 c_func = c->c_func; 647 c_arg = c->c_arg; 648 c_iflags = c->c_iflags; 649 c->c_iflags &= ~CALLOUT_PENDING; 650 651 cc_exec_curr(cc, direct) = c; 652 cc_exec_last_func(cc, direct) = c_func; 653 cc_exec_last_arg(cc, direct) = c_arg; 654 cc_exec_cancel(cc, direct) = false; 655 cc_exec_drain(cc, direct) = NULL; 656 CC_UNLOCK(cc); 657 if (c_lock != NULL) { 658 class->lc_lock(c_lock, lock_status); 659 /* 660 * The callout may have been cancelled 661 * while we switched locks. 662 */ 663 if (cc_exec_cancel(cc, direct)) { 664 class->lc_unlock(c_lock); 665 goto skip; 666 } 667 /* The callout cannot be stopped now. */ 668 cc_exec_cancel(cc, direct) = true; 669 if (c_lock == &Giant.lock_object) { 670 #ifdef CALLOUT_PROFILING 671 (*gcalls)++; 672 #endif 673 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", 674 c, c_func, c_arg); 675 } else { 676 #ifdef CALLOUT_PROFILING 677 (*lockcalls)++; 678 #endif 679 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", 680 c, c_func, c_arg); 681 } 682 } else { 683 #ifdef CALLOUT_PROFILING 684 (*mpcalls)++; 685 #endif 686 CTR3(KTR_CALLOUT, "callout %p func %p arg %p", 687 c, c_func, c_arg); 688 } 689 KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running", 690 "func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct); 691 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 692 sbt1 = sbinuptime(); 693 #endif 694 THREAD_NO_SLEEPING(); 695 SDT_PROBE1(callout_execute, , , callout__start, c); 696 c_func(c_arg); 697 SDT_PROBE1(callout_execute, , , callout__end, c); 698 THREAD_SLEEPING_OK(); 699 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 700 sbt2 = sbinuptime(); 701 sbt2 -= sbt1; 702 if (sbt2 > maxdt) { 703 if (lastfunc != c_func || sbt2 > maxdt * 2) { 704 ts2 = sbttots(sbt2); 705 printf( 706 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 707 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); 708 } 709 maxdt = sbt2; 710 lastfunc = c_func; 711 } 712 #endif 713 KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle"); 714 CTR1(KTR_CALLOUT, "callout %p finished", c); 715 if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0) 716 class->lc_unlock(c_lock); 717 skip: 718 CC_LOCK(cc); 719 KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr")); 720 cc_exec_curr(cc, direct) = NULL; 721 if (cc_exec_drain(cc, direct)) { 722 drain = cc_exec_drain(cc, direct); 723 cc_exec_drain(cc, direct) = NULL; 724 CC_UNLOCK(cc); 725 drain(c_arg); 726 CC_LOCK(cc); 727 } 728 if (cc_exec_waiting(cc, direct)) { 729 /* 730 * There is someone waiting for the 731 * callout to complete. 732 * If the callout was scheduled for 733 * migration just cancel it. 734 */ 735 if (cc_cce_migrating(cc, direct)) { 736 cc_cce_cleanup(cc, direct); 737 738 /* 739 * It should be assert here that the callout is not 740 * destroyed but that is not easy. 741 */ 742 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 743 } 744 cc_exec_waiting(cc, direct) = false; 745 CC_UNLOCK(cc); 746 wakeup(&cc_exec_waiting(cc, direct)); 747 CC_LOCK(cc); 748 } else if (cc_cce_migrating(cc, direct)) { 749 #ifdef SMP 750 /* 751 * If the callout was scheduled for 752 * migration just perform it now. 753 */ 754 new_cpu = cc_migration_cpu(cc, direct); 755 new_time = cc_migration_time(cc, direct); 756 new_prec = cc_migration_prec(cc, direct); 757 new_func = cc_migration_func(cc, direct); 758 new_arg = cc_migration_arg(cc, direct); 759 cc_cce_cleanup(cc, direct); 760 761 /* 762 * It should be assert here that the callout is not destroyed 763 * but that is not easy. 764 * 765 * As first thing, handle deferred callout stops. 766 */ 767 if (!callout_migrating(c)) { 768 CTR3(KTR_CALLOUT, 769 "deferred cancelled %p func %p arg %p", 770 c, new_func, new_arg); 771 return; 772 } 773 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 774 775 new_cc = callout_cpu_switch(c, cc, new_cpu); 776 flags = (direct) ? C_DIRECT_EXEC : 0; 777 callout_cc_add(c, new_cc, new_time, new_prec, new_func, 778 new_arg, new_cpu, flags); 779 CC_UNLOCK(new_cc); 780 CC_LOCK(cc); 781 #else 782 panic("migration should not happen"); 783 #endif 784 } 785 } 786 787 /* 788 * The callout mechanism is based on the work of Adam M. Costello and 789 * George Varghese, published in a technical report entitled "Redesigning 790 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 791 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 792 * used in this implementation was published by G. Varghese and T. Lauck in 793 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 794 * the Efficient Implementation of a Timer Facility" in the Proceedings of 795 * the 11th ACM Annual Symposium on Operating Systems Principles, 796 * Austin, Texas Nov 1987. 797 */ 798 799 /* 800 * Software (low priority) clock interrupt. 801 * Run periodic events from timeout queue. 802 */ 803 void 804 softclock(void *arg) 805 { 806 struct callout_cpu *cc; 807 struct callout *c; 808 #ifdef CALLOUT_PROFILING 809 int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0; 810 #endif 811 812 cc = (struct callout_cpu *)arg; 813 CC_LOCK(cc); 814 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { 815 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 816 softclock_call_cc(c, cc, 817 #ifdef CALLOUT_PROFILING 818 &mpcalls, &lockcalls, &gcalls, 819 #endif 820 0); 821 #ifdef CALLOUT_PROFILING 822 ++depth; 823 #endif 824 } 825 #ifdef CALLOUT_PROFILING 826 avg_depth += (depth * 1000 - avg_depth) >> 8; 827 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 828 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 829 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 830 #endif 831 CC_UNLOCK(cc); 832 } 833 834 void 835 callout_when(sbintime_t sbt, sbintime_t precision, int flags, 836 sbintime_t *res, sbintime_t *prec_res) 837 { 838 sbintime_t to_sbt, to_pr; 839 840 if ((flags & (C_ABSOLUTE | C_PRECALC)) != 0) { 841 *res = sbt; 842 *prec_res = precision; 843 return; 844 } 845 if ((flags & C_HARDCLOCK) != 0 && sbt < tick_sbt) 846 sbt = tick_sbt; 847 if ((flags & C_HARDCLOCK) != 0 || sbt >= sbt_tickthreshold) { 848 /* 849 * Obtain the time of the last hardclock() call on 850 * this CPU directly from the kern_clocksource.c. 851 * This value is per-CPU, but it is equal for all 852 * active ones. 853 */ 854 #ifdef __LP64__ 855 to_sbt = DPCPU_GET(hardclocktime); 856 #else 857 spinlock_enter(); 858 to_sbt = DPCPU_GET(hardclocktime); 859 spinlock_exit(); 860 #endif 861 if (cold && to_sbt == 0) 862 to_sbt = sbinuptime(); 863 if ((flags & C_HARDCLOCK) == 0) 864 to_sbt += tick_sbt; 865 } else 866 to_sbt = sbinuptime(); 867 if (SBT_MAX - to_sbt < sbt) 868 to_sbt = SBT_MAX; 869 else 870 to_sbt += sbt; 871 *res = to_sbt; 872 to_pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : 873 sbt >> C_PRELGET(flags)); 874 *prec_res = to_pr > precision ? to_pr : precision; 875 } 876 877 /* 878 * New interface; clients allocate their own callout structures. 879 * 880 * callout_reset() - establish or change a timeout 881 * callout_stop() - disestablish a timeout 882 * callout_init() - initialize a callout structure so that it can 883 * safely be passed to callout_reset() and callout_stop() 884 * 885 * <sys/callout.h> defines three convenience macros: 886 * 887 * callout_active() - returns truth if callout has not been stopped, 888 * drained, or deactivated since the last time the callout was 889 * reset. 890 * callout_pending() - returns truth if callout is still waiting for timeout 891 * callout_deactivate() - marks the callout as having been serviced 892 */ 893 int 894 callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t prec, 895 callout_func_t *ftn, void *arg, int cpu, int flags) 896 { 897 sbintime_t to_sbt, precision; 898 struct callout_cpu *cc; 899 int cancelled, direct; 900 int ignore_cpu=0; 901 902 cancelled = 0; 903 if (cpu == -1) { 904 ignore_cpu = 1; 905 } else if ((cpu >= MAXCPU) || 906 ((CC_CPU(cpu))->cc_inited == 0)) { 907 /* Invalid CPU spec */ 908 panic("Invalid CPU in callout %d", cpu); 909 } 910 callout_when(sbt, prec, flags, &to_sbt, &precision); 911 912 /* 913 * This flag used to be added by callout_cc_add, but the 914 * first time you call this we could end up with the 915 * wrong direct flag if we don't do it before we add. 916 */ 917 if (flags & C_DIRECT_EXEC) { 918 direct = 1; 919 } else { 920 direct = 0; 921 } 922 KASSERT(!direct || c->c_lock == NULL || 923 (LOCK_CLASS(c->c_lock)->lc_flags & LC_SPINLOCK), 924 ("%s: direct callout %p has non-spin lock", __func__, c)); 925 cc = callout_lock(c); 926 /* 927 * Don't allow migration if the user does not care. 928 */ 929 if (ignore_cpu) { 930 cpu = c->c_cpu; 931 } 932 933 if (cc_exec_curr(cc, direct) == c) { 934 /* 935 * We're being asked to reschedule a callout which is 936 * currently in progress. If there is a lock then we 937 * can cancel the callout if it has not really started. 938 */ 939 if (c->c_lock != NULL && !cc_exec_cancel(cc, direct)) 940 cancelled = cc_exec_cancel(cc, direct) = true; 941 if (cc_exec_waiting(cc, direct) || cc_exec_drain(cc, direct)) { 942 /* 943 * Someone has called callout_drain to kill this 944 * callout. Don't reschedule. 945 */ 946 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 947 cancelled ? "cancelled" : "failed to cancel", 948 c, c->c_func, c->c_arg); 949 CC_UNLOCK(cc); 950 return (cancelled); 951 } 952 #ifdef SMP 953 if (callout_migrating(c)) { 954 /* 955 * This only occurs when a second callout_reset_sbt_on 956 * is made after a previous one moved it into 957 * deferred migration (below). Note we do *not* change 958 * the prev_cpu even though the previous target may 959 * be different. 960 */ 961 cc_migration_cpu(cc, direct) = cpu; 962 cc_migration_time(cc, direct) = to_sbt; 963 cc_migration_prec(cc, direct) = precision; 964 cc_migration_func(cc, direct) = ftn; 965 cc_migration_arg(cc, direct) = arg; 966 cancelled = 1; 967 CC_UNLOCK(cc); 968 return (cancelled); 969 } 970 #endif 971 } 972 if (c->c_iflags & CALLOUT_PENDING) { 973 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 974 if (cc_exec_next(cc) == c) 975 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 976 LIST_REMOVE(c, c_links.le); 977 } else { 978 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 979 } 980 cancelled = 1; 981 c->c_iflags &= ~ CALLOUT_PENDING; 982 c->c_flags &= ~ CALLOUT_ACTIVE; 983 } 984 985 #ifdef SMP 986 /* 987 * If the callout must migrate try to perform it immediately. 988 * If the callout is currently running, just defer the migration 989 * to a more appropriate moment. 990 */ 991 if (c->c_cpu != cpu) { 992 if (cc_exec_curr(cc, direct) == c) { 993 /* 994 * Pending will have been removed since we are 995 * actually executing the callout on another 996 * CPU. That callout should be waiting on the 997 * lock the caller holds. If we set both 998 * active/and/pending after we return and the 999 * lock on the executing callout proceeds, it 1000 * will then see pending is true and return. 1001 * At the return from the actual callout execution 1002 * the migration will occur in softclock_call_cc 1003 * and this new callout will be placed on the 1004 * new CPU via a call to callout_cpu_switch() which 1005 * will get the lock on the right CPU followed 1006 * by a call callout_cc_add() which will add it there. 1007 * (see above in softclock_call_cc()). 1008 */ 1009 cc_migration_cpu(cc, direct) = cpu; 1010 cc_migration_time(cc, direct) = to_sbt; 1011 cc_migration_prec(cc, direct) = precision; 1012 cc_migration_func(cc, direct) = ftn; 1013 cc_migration_arg(cc, direct) = arg; 1014 c->c_iflags |= (CALLOUT_DFRMIGRATION | CALLOUT_PENDING); 1015 c->c_flags |= CALLOUT_ACTIVE; 1016 CTR6(KTR_CALLOUT, 1017 "migration of %p func %p arg %p in %d.%08x to %u deferred", 1018 c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1019 (u_int)(to_sbt & 0xffffffff), cpu); 1020 CC_UNLOCK(cc); 1021 return (cancelled); 1022 } 1023 cc = callout_cpu_switch(c, cc, cpu); 1024 } 1025 #endif 1026 1027 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags); 1028 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", 1029 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1030 (u_int)(to_sbt & 0xffffffff)); 1031 CC_UNLOCK(cc); 1032 1033 return (cancelled); 1034 } 1035 1036 /* 1037 * Common idioms that can be optimized in the future. 1038 */ 1039 int 1040 callout_schedule_on(struct callout *c, int to_ticks, int cpu) 1041 { 1042 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 1043 } 1044 1045 int 1046 callout_schedule(struct callout *c, int to_ticks) 1047 { 1048 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 1049 } 1050 1051 int 1052 _callout_stop_safe(struct callout *c, int flags, callout_func_t *drain) 1053 { 1054 struct callout_cpu *cc, *old_cc; 1055 struct lock_class *class; 1056 int direct, sq_locked, use_lock; 1057 int cancelled, not_on_a_list; 1058 1059 if ((flags & CS_DRAIN) != 0) 1060 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock, 1061 "calling %s", __func__); 1062 1063 KASSERT((flags & CS_DRAIN) == 0 || drain == NULL, 1064 ("Cannot set drain callback and CS_DRAIN flag at the same time")); 1065 1066 /* 1067 * Some old subsystems don't hold Giant while running a callout_stop(), 1068 * so just discard this check for the moment. 1069 */ 1070 if ((flags & CS_DRAIN) == 0 && c->c_lock != NULL) { 1071 if (c->c_lock == &Giant.lock_object) 1072 use_lock = mtx_owned(&Giant); 1073 else { 1074 use_lock = 1; 1075 class = LOCK_CLASS(c->c_lock); 1076 class->lc_assert(c->c_lock, LA_XLOCKED); 1077 } 1078 } else 1079 use_lock = 0; 1080 if (c->c_iflags & CALLOUT_DIRECT) { 1081 direct = 1; 1082 } else { 1083 direct = 0; 1084 } 1085 sq_locked = 0; 1086 old_cc = NULL; 1087 again: 1088 cc = callout_lock(c); 1089 1090 if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) == 1091 (CALLOUT_DFRMIGRATION | CALLOUT_PENDING) && 1092 ((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) { 1093 /* 1094 * Special case where this slipped in while we 1095 * were migrating *as* the callout is about to 1096 * execute. The caller probably holds the lock 1097 * the callout wants. 1098 * 1099 * Get rid of the migration first. Then set 1100 * the flag that tells this code *not* to 1101 * try to remove it from any lists (its not 1102 * on one yet). When the callout wheel runs, 1103 * it will ignore this callout. 1104 */ 1105 c->c_iflags &= ~CALLOUT_PENDING; 1106 c->c_flags &= ~CALLOUT_ACTIVE; 1107 not_on_a_list = 1; 1108 } else { 1109 not_on_a_list = 0; 1110 } 1111 1112 /* 1113 * If the callout was migrating while the callout cpu lock was 1114 * dropped, just drop the sleepqueue lock and check the states 1115 * again. 1116 */ 1117 if (sq_locked != 0 && cc != old_cc) { 1118 #ifdef SMP 1119 CC_UNLOCK(cc); 1120 sleepq_release(&cc_exec_waiting(old_cc, direct)); 1121 sq_locked = 0; 1122 old_cc = NULL; 1123 goto again; 1124 #else 1125 panic("migration should not happen"); 1126 #endif 1127 } 1128 1129 /* 1130 * If the callout is running, try to stop it or drain it. 1131 */ 1132 if (cc_exec_curr(cc, direct) == c) { 1133 /* 1134 * Succeed we to stop it or not, we must clear the 1135 * active flag - this is what API users expect. If we're 1136 * draining and the callout is currently executing, first wait 1137 * until it finishes. 1138 */ 1139 if ((flags & CS_DRAIN) == 0) 1140 c->c_flags &= ~CALLOUT_ACTIVE; 1141 1142 if ((flags & CS_DRAIN) != 0) { 1143 /* 1144 * The current callout is running (or just 1145 * about to run) and blocking is allowed, so 1146 * just wait for the current invocation to 1147 * finish. 1148 */ 1149 if (cc_exec_curr(cc, direct) == c) { 1150 /* 1151 * Use direct calls to sleepqueue interface 1152 * instead of cv/msleep in order to avoid 1153 * a LOR between cc_lock and sleepqueue 1154 * chain spinlocks. This piece of code 1155 * emulates a msleep_spin() call actually. 1156 * 1157 * If we already have the sleepqueue chain 1158 * locked, then we can safely block. If we 1159 * don't already have it locked, however, 1160 * we have to drop the cc_lock to lock 1161 * it. This opens several races, so we 1162 * restart at the beginning once we have 1163 * both locks. If nothing has changed, then 1164 * we will end up back here with sq_locked 1165 * set. 1166 */ 1167 if (!sq_locked) { 1168 CC_UNLOCK(cc); 1169 sleepq_lock( 1170 &cc_exec_waiting(cc, direct)); 1171 sq_locked = 1; 1172 old_cc = cc; 1173 goto again; 1174 } 1175 1176 /* 1177 * Migration could be cancelled here, but 1178 * as long as it is still not sure when it 1179 * will be packed up, just let softclock() 1180 * take care of it. 1181 */ 1182 cc_exec_waiting(cc, direct) = true; 1183 DROP_GIANT(); 1184 CC_UNLOCK(cc); 1185 sleepq_add( 1186 &cc_exec_waiting(cc, direct), 1187 &cc->cc_lock.lock_object, "codrain", 1188 SLEEPQ_SLEEP, 0); 1189 sleepq_wait( 1190 &cc_exec_waiting(cc, direct), 1191 0); 1192 sq_locked = 0; 1193 old_cc = NULL; 1194 1195 /* Reacquire locks previously released. */ 1196 PICKUP_GIANT(); 1197 goto again; 1198 } 1199 c->c_flags &= ~CALLOUT_ACTIVE; 1200 } else if (use_lock && 1201 !cc_exec_cancel(cc, direct) && (drain == NULL)) { 1202 1203 /* 1204 * The current callout is waiting for its 1205 * lock which we hold. Cancel the callout 1206 * and return. After our caller drops the 1207 * lock, the callout will be skipped in 1208 * softclock(). This *only* works with a 1209 * callout_stop() *not* callout_drain() or 1210 * callout_async_drain(). 1211 */ 1212 cc_exec_cancel(cc, direct) = true; 1213 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1214 c, c->c_func, c->c_arg); 1215 KASSERT(!cc_cce_migrating(cc, direct), 1216 ("callout wrongly scheduled for migration")); 1217 if (callout_migrating(c)) { 1218 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1219 #ifdef SMP 1220 cc_migration_cpu(cc, direct) = CPUBLOCK; 1221 cc_migration_time(cc, direct) = 0; 1222 cc_migration_prec(cc, direct) = 0; 1223 cc_migration_func(cc, direct) = NULL; 1224 cc_migration_arg(cc, direct) = NULL; 1225 #endif 1226 } 1227 CC_UNLOCK(cc); 1228 KASSERT(!sq_locked, ("sleepqueue chain locked")); 1229 return (1); 1230 } else if (callout_migrating(c)) { 1231 /* 1232 * The callout is currently being serviced 1233 * and the "next" callout is scheduled at 1234 * its completion with a migration. We remove 1235 * the migration flag so it *won't* get rescheduled, 1236 * but we can't stop the one thats running so 1237 * we return 0. 1238 */ 1239 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1240 #ifdef SMP 1241 /* 1242 * We can't call cc_cce_cleanup here since 1243 * if we do it will remove .ce_curr and 1244 * its still running. This will prevent a 1245 * reschedule of the callout when the 1246 * execution completes. 1247 */ 1248 cc_migration_cpu(cc, direct) = CPUBLOCK; 1249 cc_migration_time(cc, direct) = 0; 1250 cc_migration_prec(cc, direct) = 0; 1251 cc_migration_func(cc, direct) = NULL; 1252 cc_migration_arg(cc, direct) = NULL; 1253 #endif 1254 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 1255 c, c->c_func, c->c_arg); 1256 if (drain) { 1257 KASSERT(cc_exec_drain(cc, direct) == NULL, 1258 ("callout drain function already set to %p", 1259 cc_exec_drain(cc, direct))); 1260 cc_exec_drain(cc, direct) = drain; 1261 } 1262 CC_UNLOCK(cc); 1263 return ((flags & CS_EXECUTING) != 0); 1264 } else { 1265 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1266 c, c->c_func, c->c_arg); 1267 if (drain) { 1268 KASSERT(cc_exec_drain(cc, direct) == NULL, 1269 ("callout drain function already set to %p", 1270 cc_exec_drain(cc, direct))); 1271 cc_exec_drain(cc, direct) = drain; 1272 } 1273 } 1274 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 1275 cancelled = ((flags & CS_EXECUTING) != 0); 1276 } else 1277 cancelled = 1; 1278 1279 if (sq_locked) 1280 sleepq_release(&cc_exec_waiting(cc, direct)); 1281 1282 if ((c->c_iflags & CALLOUT_PENDING) == 0) { 1283 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1284 c, c->c_func, c->c_arg); 1285 /* 1286 * For not scheduled and not executing callout return 1287 * negative value. 1288 */ 1289 if (cc_exec_curr(cc, direct) != c) 1290 cancelled = -1; 1291 CC_UNLOCK(cc); 1292 return (cancelled); 1293 } 1294 1295 c->c_iflags &= ~CALLOUT_PENDING; 1296 c->c_flags &= ~CALLOUT_ACTIVE; 1297 1298 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1299 c, c->c_func, c->c_arg); 1300 if (not_on_a_list == 0) { 1301 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1302 if (cc_exec_next(cc) == c) 1303 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1304 LIST_REMOVE(c, c_links.le); 1305 } else { 1306 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1307 } 1308 } 1309 CC_UNLOCK(cc); 1310 return (cancelled); 1311 } 1312 1313 void 1314 callout_init(struct callout *c, int mpsafe) 1315 { 1316 bzero(c, sizeof *c); 1317 if (mpsafe) { 1318 c->c_lock = NULL; 1319 c->c_iflags = CALLOUT_RETURNUNLOCKED; 1320 } else { 1321 c->c_lock = &Giant.lock_object; 1322 c->c_iflags = 0; 1323 } 1324 c->c_cpu = cc_default_cpu; 1325 } 1326 1327 void 1328 _callout_init_lock(struct callout *c, struct lock_object *lock, int flags) 1329 { 1330 bzero(c, sizeof *c); 1331 c->c_lock = lock; 1332 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1333 ("callout_init_lock: bad flags %d", flags)); 1334 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1335 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1336 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & LC_SLEEPABLE), 1337 ("%s: callout %p has sleepable lock", __func__, c)); 1338 c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1339 c->c_cpu = cc_default_cpu; 1340 } 1341 1342 static int 1343 flssbt(sbintime_t sbt) 1344 { 1345 1346 sbt += (uint64_t)sbt >> 1; 1347 if (sizeof(long) >= sizeof(sbintime_t)) 1348 return (flsl(sbt)); 1349 if (sbt >= SBT_1S) 1350 return (flsl(((uint64_t)sbt) >> 32) + 32); 1351 return (flsl(sbt)); 1352 } 1353 1354 /* 1355 * Dump immediate statistic snapshot of the scheduled callouts. 1356 */ 1357 static int 1358 sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1359 { 1360 struct callout *tmp; 1361 struct callout_cpu *cc; 1362 struct callout_list *sc; 1363 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; 1364 int ct[64], cpr[64], ccpbk[32]; 1365 int error, val, i, count, tcum, pcum, maxc, c, medc; 1366 int cpu; 1367 1368 val = 0; 1369 error = sysctl_handle_int(oidp, &val, 0, req); 1370 if (error != 0 || req->newptr == NULL) 1371 return (error); 1372 count = maxc = 0; 1373 st = spr = maxt = maxpr = 0; 1374 bzero(ccpbk, sizeof(ccpbk)); 1375 bzero(ct, sizeof(ct)); 1376 bzero(cpr, sizeof(cpr)); 1377 now = sbinuptime(); 1378 CPU_FOREACH(cpu) { 1379 cc = CC_CPU(cpu); 1380 CC_LOCK(cc); 1381 for (i = 0; i < callwheelsize; i++) { 1382 sc = &cc->cc_callwheel[i]; 1383 c = 0; 1384 LIST_FOREACH(tmp, sc, c_links.le) { 1385 c++; 1386 t = tmp->c_time - now; 1387 if (t < 0) 1388 t = 0; 1389 st += t / SBT_1US; 1390 spr += tmp->c_precision / SBT_1US; 1391 if (t > maxt) 1392 maxt = t; 1393 if (tmp->c_precision > maxpr) 1394 maxpr = tmp->c_precision; 1395 ct[flssbt(t)]++; 1396 cpr[flssbt(tmp->c_precision)]++; 1397 } 1398 if (c > maxc) 1399 maxc = c; 1400 ccpbk[fls(c + c / 2)]++; 1401 count += c; 1402 } 1403 CC_UNLOCK(cc); 1404 } 1405 1406 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1407 tcum += ct[i]; 1408 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1409 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) 1410 pcum += cpr[i]; 1411 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1412 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1413 c += ccpbk[i]; 1414 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1415 1416 printf("Scheduled callouts statistic snapshot:\n"); 1417 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1418 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1419 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1420 medc, 1421 count / callwheelsize / mp_ncpus, 1422 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1423 maxc); 1424 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1425 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1426 (st / count) / 1000000, (st / count) % 1000000, 1427 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); 1428 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1429 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, 1430 (spr / count) / 1000000, (spr / count) % 1000000, 1431 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); 1432 printf(" Distribution: \tbuckets\t time\t tcum\t" 1433 " prec\t pcum\n"); 1434 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1435 if (ct[i] == 0 && cpr[i] == 0) 1436 continue; 1437 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1438 tcum += ct[i]; 1439 pcum += cpr[i]; 1440 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", 1441 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1442 i - 1 - (32 - CC_HASH_SHIFT), 1443 ct[i], tcum, cpr[i], pcum); 1444 } 1445 return (error); 1446 } 1447 SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1448 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1449 0, 0, sysctl_kern_callout_stat, "I", 1450 "Dump immediate statistic snapshot of the scheduled callouts"); 1451 1452 #ifdef DDB 1453 static void 1454 _show_callout(struct callout *c) 1455 { 1456 1457 db_printf("callout %p\n", c); 1458 #define C_DB_PRINTF(f, e) db_printf(" %s = " f "\n", #e, c->e); 1459 db_printf(" &c_links = %p\n", &(c->c_links)); 1460 C_DB_PRINTF("%" PRId64, c_time); 1461 C_DB_PRINTF("%" PRId64, c_precision); 1462 C_DB_PRINTF("%p", c_arg); 1463 C_DB_PRINTF("%p", c_func); 1464 C_DB_PRINTF("%p", c_lock); 1465 C_DB_PRINTF("%#x", c_flags); 1466 C_DB_PRINTF("%#x", c_iflags); 1467 C_DB_PRINTF("%d", c_cpu); 1468 #undef C_DB_PRINTF 1469 } 1470 1471 DB_SHOW_COMMAND(callout, db_show_callout) 1472 { 1473 1474 if (!have_addr) { 1475 db_printf("usage: show callout <struct callout *>\n"); 1476 return; 1477 } 1478 1479 _show_callout((struct callout *)addr); 1480 } 1481 1482 static void 1483 _show_last_callout(int cpu, int direct, const char *dirstr) 1484 { 1485 struct callout_cpu *cc; 1486 void *func, *arg; 1487 1488 cc = CC_CPU(cpu); 1489 func = cc_exec_last_func(cc, direct); 1490 arg = cc_exec_last_arg(cc, direct); 1491 db_printf("cpu %d last%s callout function: %p ", cpu, dirstr, func); 1492 db_printsym((db_expr_t)func, DB_STGY_ANY); 1493 db_printf("\ncpu %d last%s callout argument: %p\n", cpu, dirstr, arg); 1494 } 1495 1496 DB_SHOW_COMMAND(callout_last, db_show_callout_last) 1497 { 1498 int cpu, last; 1499 1500 if (have_addr) { 1501 if (addr < 0 || addr > mp_maxid || CPU_ABSENT(addr)) { 1502 db_printf("no such cpu: %d\n", (int)addr); 1503 return; 1504 } 1505 cpu = last = addr; 1506 } else { 1507 cpu = 0; 1508 last = mp_maxid; 1509 } 1510 1511 while (cpu <= last) { 1512 if (!CPU_ABSENT(cpu)) { 1513 _show_last_callout(cpu, 0, ""); 1514 _show_last_callout(cpu, 1, " direct"); 1515 } 1516 cpu++; 1517 } 1518 } 1519 #endif /* DDB */
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