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 #if defined(__arm__) 45 #include "opt_timer.h" 46 #endif 47 #include "opt_rss.h" 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/bus.h> 52 #include <sys/callout.h> 53 #include <sys/domainset.h> 54 #include <sys/file.h> 55 #include <sys/interrupt.h> 56 #include <sys/kernel.h> 57 #include <sys/ktr.h> 58 #include <sys/lock.h> 59 #include <sys/malloc.h> 60 #include <sys/mutex.h> 61 #include <sys/proc.h> 62 #include <sys/sdt.h> 63 #include <sys/sleepqueue.h> 64 #include <sys/sysctl.h> 65 #include <sys/smp.h> 66 67 #ifdef DDB 68 #include <ddb/ddb.h> 69 #include <ddb/db_sym.h> 70 #include <machine/_inttypes.h> 71 #endif 72 73 #ifdef SMP 74 #include <machine/cpu.h> 75 #endif 76 77 #ifndef NO_EVENTTIMERS 78 DPCPU_DECLARE(sbintime_t, hardclocktime); 79 #endif 80 81 SDT_PROVIDER_DEFINE(callout_execute); 82 SDT_PROBE_DEFINE1(callout_execute, , , callout__start, "struct callout *"); 83 SDT_PROBE_DEFINE1(callout_execute, , , callout__end, "struct callout *"); 84 85 #ifdef CALLOUT_PROFILING 86 static int avg_depth; 87 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, 88 "Average number of items examined per softclock call. Units = 1/1000"); 89 static int avg_gcalls; 90 SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, 91 "Average number of Giant callouts made per softclock call. Units = 1/1000"); 92 static int avg_lockcalls; 93 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0, 94 "Average number of lock callouts made per softclock call. Units = 1/1000"); 95 static int avg_mpcalls; 96 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, 97 "Average number of MP callouts made per softclock call. Units = 1/1000"); 98 static int avg_depth_dir; 99 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0, 100 "Average number of direct callouts examined per callout_process call. " 101 "Units = 1/1000"); 102 static int avg_lockcalls_dir; 103 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD, 104 &avg_lockcalls_dir, 0, "Average number of lock direct callouts made per " 105 "callout_process call. Units = 1/1000"); 106 static int avg_mpcalls_dir; 107 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir, 108 0, "Average number of MP direct callouts made per callout_process call. " 109 "Units = 1/1000"); 110 #endif 111 112 static int ncallout; 113 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &ncallout, 0, 114 "Number of entries in callwheel and size of timeout() preallocation"); 115 116 #ifdef RSS 117 static int pin_default_swi = 1; 118 static int pin_pcpu_swi = 1; 119 #else 120 static int pin_default_swi = 0; 121 static int pin_pcpu_swi = 0; 122 #endif 123 124 SYSCTL_INT(_kern, OID_AUTO, pin_default_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_default_swi, 125 0, "Pin the default (non-per-cpu) swi (shared with PCPU 0 swi)"); 126 SYSCTL_INT(_kern, OID_AUTO, pin_pcpu_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_pcpu_swi, 127 0, "Pin the per-CPU swis (except PCPU 0, which is also default"); 128 129 /* 130 * TODO: 131 * allocate more timeout table slots when table overflows. 132 */ 133 static u_int __read_mostly callwheelsize; 134 static u_int __read_mostly callwheelmask; 135 136 /* 137 * The callout cpu exec entities represent informations necessary for 138 * describing the state of callouts currently running on the CPU and the ones 139 * necessary for migrating callouts to the new callout cpu. In particular, 140 * the first entry of the array cc_exec_entity holds informations for callout 141 * running in SWI thread context, while the second one holds informations 142 * for callout running directly from hardware interrupt context. 143 * The cached informations are very important for deferring migration when 144 * the migrating callout is already running. 145 */ 146 struct cc_exec { 147 struct callout *cc_curr; 148 callout_func_t *cc_drain; 149 void *cc_last_func; 150 void *cc_last_arg; 151 #ifdef SMP 152 callout_func_t *ce_migration_func; 153 void *ce_migration_arg; 154 sbintime_t ce_migration_time; 155 sbintime_t ce_migration_prec; 156 int ce_migration_cpu; 157 #endif 158 bool cc_cancel; 159 bool cc_waiting; 160 }; 161 162 /* 163 * There is one struct callout_cpu per cpu, holding all relevant 164 * state for the callout processing thread on the individual CPU. 165 */ 166 struct callout_cpu { 167 struct mtx_padalign cc_lock; 168 struct cc_exec cc_exec_entity[2]; 169 struct callout *cc_next; 170 struct callout_list *cc_callwheel; 171 struct callout_tailq cc_expireq; 172 sbintime_t cc_firstevent; 173 sbintime_t cc_lastscan; 174 void *cc_cookie; 175 u_int cc_bucket; 176 u_int cc_inited; 177 #ifdef KTR 178 char cc_ktr_event_name[20]; 179 #endif 180 }; 181 182 #define callout_migrating(c) ((c)->c_iflags & CALLOUT_DFRMIGRATION) 183 184 #define cc_exec_curr(cc, dir) cc->cc_exec_entity[dir].cc_curr 185 #define cc_exec_last_func(cc, dir) cc->cc_exec_entity[dir].cc_last_func 186 #define cc_exec_last_arg(cc, dir) cc->cc_exec_entity[dir].cc_last_arg 187 #define cc_exec_drain(cc, dir) cc->cc_exec_entity[dir].cc_drain 188 #define cc_exec_next(cc) cc->cc_next 189 #define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel 190 #define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting 191 #ifdef SMP 192 #define cc_migration_func(cc, dir) cc->cc_exec_entity[dir].ce_migration_func 193 #define cc_migration_arg(cc, dir) cc->cc_exec_entity[dir].ce_migration_arg 194 #define cc_migration_cpu(cc, dir) cc->cc_exec_entity[dir].ce_migration_cpu 195 #define cc_migration_time(cc, dir) cc->cc_exec_entity[dir].ce_migration_time 196 #define cc_migration_prec(cc, dir) cc->cc_exec_entity[dir].ce_migration_prec 197 198 struct callout_cpu cc_cpu[MAXCPU]; 199 #define CPUBLOCK MAXCPU 200 #define CC_CPU(cpu) (&cc_cpu[(cpu)]) 201 #define CC_SELF() CC_CPU(PCPU_GET(cpuid)) 202 #else 203 struct callout_cpu cc_cpu; 204 #define CC_CPU(cpu) &cc_cpu 205 #define CC_SELF() &cc_cpu 206 #endif 207 #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) 208 #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) 209 #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) 210 211 static int __read_mostly cc_default_cpu; 212 213 static void callout_cpu_init(struct callout_cpu *cc, int cpu); 214 static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, 215 #ifdef CALLOUT_PROFILING 216 int *mpcalls, int *lockcalls, int *gcalls, 217 #endif 218 int direct); 219 220 static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); 221 222 /** 223 * Locked by cc_lock: 224 * cc_curr - If a callout is in progress, it is cc_curr. 225 * If cc_curr is non-NULL, threads waiting in 226 * callout_drain() will be woken up as soon as the 227 * relevant callout completes. 228 * cc_cancel - Changing to 1 with both callout_lock and cc_lock held 229 * guarantees that the current callout will not run. 230 * The softclock() function sets this to 0 before it 231 * drops callout_lock to acquire c_lock, and it calls 232 * the handler only if curr_cancelled is still 0 after 233 * cc_lock is successfully acquired. 234 * cc_waiting - If a thread is waiting in callout_drain(), then 235 * callout_wait is nonzero. Set only when 236 * cc_curr is non-NULL. 237 */ 238 239 /* 240 * Resets the execution entity tied to a specific callout cpu. 241 */ 242 static void 243 cc_cce_cleanup(struct callout_cpu *cc, int direct) 244 { 245 246 cc_exec_curr(cc, direct) = NULL; 247 cc_exec_cancel(cc, direct) = false; 248 cc_exec_waiting(cc, direct) = false; 249 #ifdef SMP 250 cc_migration_cpu(cc, direct) = CPUBLOCK; 251 cc_migration_time(cc, direct) = 0; 252 cc_migration_prec(cc, direct) = 0; 253 cc_migration_func(cc, direct) = NULL; 254 cc_migration_arg(cc, direct) = NULL; 255 #endif 256 } 257 258 /* 259 * Checks if migration is requested by a specific callout cpu. 260 */ 261 static int 262 cc_cce_migrating(struct callout_cpu *cc, int direct) 263 { 264 265 #ifdef SMP 266 return (cc_migration_cpu(cc, direct) != CPUBLOCK); 267 #else 268 return (0); 269 #endif 270 } 271 272 /* 273 * Kernel low level callwheel initialization 274 * called on the BSP during kernel startup. 275 */ 276 static void 277 callout_callwheel_init(void *dummy) 278 { 279 struct callout_cpu *cc; 280 int cpu; 281 282 /* 283 * Calculate the size of the callout wheel and the preallocated 284 * timeout() structures. 285 * XXX: Clip callout to result of previous function of maxusers 286 * maximum 384. This is still huge, but acceptable. 287 */ 288 memset(CC_CPU(curcpu), 0, sizeof(cc_cpu)); 289 ncallout = imin(16 + maxproc + maxfiles, 18508); 290 TUNABLE_INT_FETCH("kern.ncallout", &ncallout); 291 292 /* 293 * Calculate callout wheel size, should be next power of two higher 294 * than 'ncallout'. 295 */ 296 callwheelsize = 1 << fls(ncallout); 297 callwheelmask = callwheelsize - 1; 298 299 /* 300 * Fetch whether we're pinning the swi's or not. 301 */ 302 TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi); 303 TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi); 304 305 /* 306 * Initialize callout wheels. The software interrupt threads 307 * are created later. 308 */ 309 cc_default_cpu = PCPU_GET(cpuid); 310 CPU_FOREACH(cpu) { 311 cc = CC_CPU(cpu); 312 callout_cpu_init(cc, cpu); 313 } 314 } 315 SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); 316 317 /* 318 * Initialize the per-cpu callout structures. 319 */ 320 static void 321 callout_cpu_init(struct callout_cpu *cc, int cpu) 322 { 323 int i; 324 325 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); 326 cc->cc_inited = 1; 327 cc->cc_callwheel = malloc_domainset(sizeof(struct callout_list) * 328 callwheelsize, M_CALLOUT, 329 DOMAINSET_PREF(pcpu_find(cpu)->pc_domain), M_WAITOK); 330 for (i = 0; i < callwheelsize; i++) 331 LIST_INIT(&cc->cc_callwheel[i]); 332 TAILQ_INIT(&cc->cc_expireq); 333 cc->cc_firstevent = SBT_MAX; 334 for (i = 0; i < 2; i++) 335 cc_cce_cleanup(cc, i); 336 #ifdef KTR 337 snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name), 338 "callwheel cpu %d", cpu); 339 #endif 340 } 341 342 #ifdef SMP 343 /* 344 * Switches the cpu tied to a specific callout. 345 * The function expects a locked incoming callout cpu and returns with 346 * locked outcoming callout cpu. 347 */ 348 static struct callout_cpu * 349 callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu) 350 { 351 struct callout_cpu *new_cc; 352 353 MPASS(c != NULL && cc != NULL); 354 CC_LOCK_ASSERT(cc); 355 356 /* 357 * Avoid interrupts and preemption firing after the callout cpu 358 * is blocked in order to avoid deadlocks as the new thread 359 * may be willing to acquire the callout cpu lock. 360 */ 361 c->c_cpu = CPUBLOCK; 362 spinlock_enter(); 363 CC_UNLOCK(cc); 364 new_cc = CC_CPU(new_cpu); 365 CC_LOCK(new_cc); 366 spinlock_exit(); 367 c->c_cpu = new_cpu; 368 return (new_cc); 369 } 370 #endif 371 372 /* 373 * Start softclock threads. 374 */ 375 static void 376 start_softclock(void *dummy) 377 { 378 struct callout_cpu *cc; 379 char name[MAXCOMLEN]; 380 int cpu; 381 bool pin_swi; 382 struct intr_event *ie; 383 384 CPU_FOREACH(cpu) { 385 cc = CC_CPU(cpu); 386 snprintf(name, sizeof(name), "clock (%d)", cpu); 387 ie = NULL; 388 if (swi_add(&ie, name, softclock, cc, SWI_CLOCK, 389 INTR_MPSAFE, &cc->cc_cookie)) 390 panic("died while creating standard software ithreads"); 391 if (cpu == cc_default_cpu) 392 pin_swi = pin_default_swi; 393 else 394 pin_swi = pin_pcpu_swi; 395 if (pin_swi && (intr_event_bind(ie, cpu) != 0)) { 396 printf("%s: %s clock couldn't be pinned to cpu %d\n", 397 __func__, 398 cpu == cc_default_cpu ? "default" : "per-cpu", 399 cpu); 400 } 401 } 402 } 403 SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); 404 405 #define CC_HASH_SHIFT 8 406 407 static inline u_int 408 callout_hash(sbintime_t sbt) 409 { 410 411 return (sbt >> (32 - CC_HASH_SHIFT)); 412 } 413 414 static inline u_int 415 callout_get_bucket(sbintime_t sbt) 416 { 417 418 return (callout_hash(sbt) & callwheelmask); 419 } 420 421 void 422 callout_process(sbintime_t now) 423 { 424 struct callout *tmp, *tmpn; 425 struct callout_cpu *cc; 426 struct callout_list *sc; 427 sbintime_t first, last, max, tmp_max; 428 uint32_t lookahead; 429 u_int firstb, lastb, nowb; 430 #ifdef CALLOUT_PROFILING 431 int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0; 432 #endif 433 434 cc = CC_SELF(); 435 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET); 436 437 /* Compute the buckets of the last scan and present times. */ 438 firstb = callout_hash(cc->cc_lastscan); 439 cc->cc_lastscan = now; 440 nowb = callout_hash(now); 441 442 /* Compute the last bucket and minimum time of the bucket after it. */ 443 if (nowb == firstb) 444 lookahead = (SBT_1S / 16); 445 else if (nowb - firstb == 1) 446 lookahead = (SBT_1S / 8); 447 else 448 lookahead = (SBT_1S / 2); 449 first = last = now; 450 first += (lookahead / 2); 451 last += lookahead; 452 last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); 453 lastb = callout_hash(last) - 1; 454 max = last; 455 456 /* 457 * Check if we wrapped around the entire wheel from the last scan. 458 * In case, we need to scan entirely the wheel for pending callouts. 459 */ 460 if (lastb - firstb >= callwheelsize) { 461 lastb = firstb + callwheelsize - 1; 462 if (nowb - firstb >= callwheelsize) 463 nowb = lastb; 464 } 465 466 /* Iterate callwheel from firstb to nowb and then up to lastb. */ 467 do { 468 sc = &cc->cc_callwheel[firstb & callwheelmask]; 469 tmp = LIST_FIRST(sc); 470 while (tmp != NULL) { 471 /* Run the callout if present time within allowed. */ 472 if (tmp->c_time <= now) { 473 /* 474 * Consumer told us the callout may be run 475 * directly from hardware interrupt context. 476 */ 477 if (tmp->c_iflags & CALLOUT_DIRECT) { 478 #ifdef CALLOUT_PROFILING 479 ++depth_dir; 480 #endif 481 cc_exec_next(cc) = 482 LIST_NEXT(tmp, c_links.le); 483 cc->cc_bucket = firstb & callwheelmask; 484 LIST_REMOVE(tmp, c_links.le); 485 softclock_call_cc(tmp, cc, 486 #ifdef CALLOUT_PROFILING 487 &mpcalls_dir, &lockcalls_dir, NULL, 488 #endif 489 1); 490 tmp = cc_exec_next(cc); 491 cc_exec_next(cc) = NULL; 492 } else { 493 tmpn = LIST_NEXT(tmp, c_links.le); 494 LIST_REMOVE(tmp, c_links.le); 495 TAILQ_INSERT_TAIL(&cc->cc_expireq, 496 tmp, c_links.tqe); 497 tmp->c_iflags |= CALLOUT_PROCESSED; 498 tmp = tmpn; 499 } 500 continue; 501 } 502 /* Skip events from distant future. */ 503 if (tmp->c_time >= max) 504 goto next; 505 /* 506 * Event minimal time is bigger than present maximal 507 * time, so it cannot be aggregated. 508 */ 509 if (tmp->c_time > last) { 510 lastb = nowb; 511 goto next; 512 } 513 /* Update first and last time, respecting this event. */ 514 if (tmp->c_time < first) 515 first = tmp->c_time; 516 tmp_max = tmp->c_time + tmp->c_precision; 517 if (tmp_max < last) 518 last = tmp_max; 519 next: 520 tmp = LIST_NEXT(tmp, c_links.le); 521 } 522 /* Proceed with the next bucket. */ 523 firstb++; 524 /* 525 * Stop if we looked after present time and found 526 * some event we can't execute at now. 527 * Stop if we looked far enough into the future. 528 */ 529 } while (((int)(firstb - lastb)) <= 0); 530 cc->cc_firstevent = last; 531 #ifndef NO_EVENTTIMERS 532 cpu_new_callout(curcpu, last, first); 533 #endif 534 #ifdef CALLOUT_PROFILING 535 avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8; 536 avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8; 537 avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8; 538 #endif 539 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 540 /* 541 * swi_sched acquires the thread lock, so we don't want to call it 542 * with cc_lock held; incorrect locking order. 543 */ 544 if (!TAILQ_EMPTY(&cc->cc_expireq)) 545 swi_sched(cc->cc_cookie, 0); 546 } 547 548 static struct callout_cpu * 549 callout_lock(struct callout *c) 550 { 551 struct callout_cpu *cc; 552 int cpu; 553 554 for (;;) { 555 cpu = c->c_cpu; 556 #ifdef SMP 557 if (cpu == CPUBLOCK) { 558 while (c->c_cpu == CPUBLOCK) 559 cpu_spinwait(); 560 continue; 561 } 562 #endif 563 cc = CC_CPU(cpu); 564 CC_LOCK(cc); 565 if (cpu == c->c_cpu) 566 break; 567 CC_UNLOCK(cc); 568 } 569 return (cc); 570 } 571 572 static void 573 callout_cc_add(struct callout *c, struct callout_cpu *cc, 574 sbintime_t sbt, sbintime_t precision, void (*func)(void *), 575 void *arg, int cpu, int flags) 576 { 577 int bucket; 578 579 CC_LOCK_ASSERT(cc); 580 if (sbt < cc->cc_lastscan) 581 sbt = cc->cc_lastscan; 582 c->c_arg = arg; 583 c->c_iflags |= CALLOUT_PENDING; 584 c->c_iflags &= ~CALLOUT_PROCESSED; 585 c->c_flags |= CALLOUT_ACTIVE; 586 if (flags & C_DIRECT_EXEC) 587 c->c_iflags |= CALLOUT_DIRECT; 588 c->c_func = func; 589 c->c_time = sbt; 590 c->c_precision = precision; 591 bucket = callout_get_bucket(c->c_time); 592 CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x", 593 c, (int)(c->c_precision >> 32), 594 (u_int)(c->c_precision & 0xffffffff)); 595 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); 596 if (cc->cc_bucket == bucket) 597 cc_exec_next(cc) = c; 598 #ifndef NO_EVENTTIMERS 599 /* 600 * Inform the eventtimers(4) subsystem there's a new callout 601 * that has been inserted, but only if really required. 602 */ 603 if (SBT_MAX - c->c_time < c->c_precision) 604 c->c_precision = SBT_MAX - c->c_time; 605 sbt = c->c_time + c->c_precision; 606 if (sbt < cc->cc_firstevent) { 607 cc->cc_firstevent = sbt; 608 cpu_new_callout(cpu, sbt, c->c_time); 609 } 610 #endif 611 } 612 613 static void 614 softclock_call_cc(struct callout *c, struct callout_cpu *cc, 615 #ifdef CALLOUT_PROFILING 616 int *mpcalls, int *lockcalls, int *gcalls, 617 #endif 618 int direct) 619 { 620 struct rm_priotracker tracker; 621 callout_func_t *c_func, *drain; 622 void *c_arg; 623 struct lock_class *class; 624 struct lock_object *c_lock; 625 uintptr_t lock_status; 626 int c_iflags; 627 #ifdef SMP 628 struct callout_cpu *new_cc; 629 callout_func_t *new_func; 630 void *new_arg; 631 int flags, new_cpu; 632 sbintime_t new_prec, new_time; 633 #endif 634 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 635 sbintime_t sbt1, sbt2; 636 struct timespec ts2; 637 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 638 static callout_func_t *lastfunc; 639 #endif 640 641 KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING, 642 ("softclock_call_cc: pend %p %x", c, c->c_iflags)); 643 KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE, 644 ("softclock_call_cc: act %p %x", c, c->c_flags)); 645 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; 646 lock_status = 0; 647 if (c->c_flags & CALLOUT_SHAREDLOCK) { 648 if (class == &lock_class_rm) 649 lock_status = (uintptr_t)&tracker; 650 else 651 lock_status = 1; 652 } 653 c_lock = c->c_lock; 654 c_func = c->c_func; 655 c_arg = c->c_arg; 656 c_iflags = c->c_iflags; 657 c->c_iflags &= ~CALLOUT_PENDING; 658 659 cc_exec_curr(cc, direct) = c; 660 cc_exec_last_func(cc, direct) = c_func; 661 cc_exec_last_arg(cc, direct) = c_arg; 662 cc_exec_cancel(cc, direct) = false; 663 cc_exec_drain(cc, direct) = NULL; 664 CC_UNLOCK(cc); 665 if (c_lock != NULL) { 666 class->lc_lock(c_lock, lock_status); 667 /* 668 * The callout may have been cancelled 669 * while we switched locks. 670 */ 671 if (cc_exec_cancel(cc, direct)) { 672 class->lc_unlock(c_lock); 673 goto skip; 674 } 675 /* The callout cannot be stopped now. */ 676 cc_exec_cancel(cc, direct) = true; 677 if (c_lock == &Giant.lock_object) { 678 #ifdef CALLOUT_PROFILING 679 (*gcalls)++; 680 #endif 681 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", 682 c, c_func, c_arg); 683 } else { 684 #ifdef CALLOUT_PROFILING 685 (*lockcalls)++; 686 #endif 687 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", 688 c, c_func, c_arg); 689 } 690 } else { 691 #ifdef CALLOUT_PROFILING 692 (*mpcalls)++; 693 #endif 694 CTR3(KTR_CALLOUT, "callout %p func %p arg %p", 695 c, c_func, c_arg); 696 } 697 KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running", 698 "func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct); 699 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 700 sbt1 = sbinuptime(); 701 #endif 702 THREAD_NO_SLEEPING(); 703 SDT_PROBE1(callout_execute, , , callout__start, c); 704 c_func(c_arg); 705 SDT_PROBE1(callout_execute, , , callout__end, c); 706 THREAD_SLEEPING_OK(); 707 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 708 sbt2 = sbinuptime(); 709 sbt2 -= sbt1; 710 if (sbt2 > maxdt) { 711 if (lastfunc != c_func || sbt2 > maxdt * 2) { 712 ts2 = sbttots(sbt2); 713 printf( 714 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 715 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); 716 } 717 maxdt = sbt2; 718 lastfunc = c_func; 719 } 720 #endif 721 KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle"); 722 CTR1(KTR_CALLOUT, "callout %p finished", c); 723 if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0) 724 class->lc_unlock(c_lock); 725 skip: 726 CC_LOCK(cc); 727 KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr")); 728 cc_exec_curr(cc, direct) = NULL; 729 if (cc_exec_drain(cc, direct)) { 730 drain = cc_exec_drain(cc, direct); 731 cc_exec_drain(cc, direct) = NULL; 732 CC_UNLOCK(cc); 733 drain(c_arg); 734 CC_LOCK(cc); 735 } 736 if (cc_exec_waiting(cc, direct)) { 737 /* 738 * There is someone waiting for the 739 * callout to complete. 740 * If the callout was scheduled for 741 * migration just cancel it. 742 */ 743 if (cc_cce_migrating(cc, direct)) { 744 cc_cce_cleanup(cc, direct); 745 746 /* 747 * It should be assert here that the callout is not 748 * destroyed but that is not easy. 749 */ 750 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 751 } 752 cc_exec_waiting(cc, direct) = false; 753 CC_UNLOCK(cc); 754 wakeup(&cc_exec_waiting(cc, direct)); 755 CC_LOCK(cc); 756 } else if (cc_cce_migrating(cc, direct)) { 757 #ifdef SMP 758 /* 759 * If the callout was scheduled for 760 * migration just perform it now. 761 */ 762 new_cpu = cc_migration_cpu(cc, direct); 763 new_time = cc_migration_time(cc, direct); 764 new_prec = cc_migration_prec(cc, direct); 765 new_func = cc_migration_func(cc, direct); 766 new_arg = cc_migration_arg(cc, direct); 767 cc_cce_cleanup(cc, direct); 768 769 /* 770 * It should be assert here that the callout is not destroyed 771 * but that is not easy. 772 * 773 * As first thing, handle deferred callout stops. 774 */ 775 if (!callout_migrating(c)) { 776 CTR3(KTR_CALLOUT, 777 "deferred cancelled %p func %p arg %p", 778 c, new_func, new_arg); 779 return; 780 } 781 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 782 783 new_cc = callout_cpu_switch(c, cc, new_cpu); 784 flags = (direct) ? C_DIRECT_EXEC : 0; 785 callout_cc_add(c, new_cc, new_time, new_prec, new_func, 786 new_arg, new_cpu, flags); 787 CC_UNLOCK(new_cc); 788 CC_LOCK(cc); 789 #else 790 panic("migration should not happen"); 791 #endif 792 } 793 } 794 795 /* 796 * The callout mechanism is based on the work of Adam M. Costello and 797 * George Varghese, published in a technical report entitled "Redesigning 798 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 799 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 800 * used in this implementation was published by G. Varghese and T. Lauck in 801 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 802 * the Efficient Implementation of a Timer Facility" in the Proceedings of 803 * the 11th ACM Annual Symposium on Operating Systems Principles, 804 * Austin, Texas Nov 1987. 805 */ 806 807 /* 808 * Software (low priority) clock interrupt. 809 * Run periodic events from timeout queue. 810 */ 811 void 812 softclock(void *arg) 813 { 814 struct callout_cpu *cc; 815 struct callout *c; 816 #ifdef CALLOUT_PROFILING 817 int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0; 818 #endif 819 820 cc = (struct callout_cpu *)arg; 821 CC_LOCK(cc); 822 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { 823 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 824 softclock_call_cc(c, cc, 825 #ifdef CALLOUT_PROFILING 826 &mpcalls, &lockcalls, &gcalls, 827 #endif 828 0); 829 #ifdef CALLOUT_PROFILING 830 ++depth; 831 #endif 832 } 833 #ifdef CALLOUT_PROFILING 834 avg_depth += (depth * 1000 - avg_depth) >> 8; 835 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 836 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 837 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 838 #endif 839 CC_UNLOCK(cc); 840 } 841 842 void 843 callout_when(sbintime_t sbt, sbintime_t precision, int flags, 844 sbintime_t *res, sbintime_t *prec_res) 845 { 846 sbintime_t to_sbt, to_pr; 847 848 if ((flags & (C_ABSOLUTE | C_PRECALC)) != 0) { 849 *res = sbt; 850 *prec_res = precision; 851 return; 852 } 853 if ((flags & C_HARDCLOCK) != 0 && sbt < tick_sbt) 854 sbt = tick_sbt; 855 if ((flags & C_HARDCLOCK) != 0 || 856 #ifdef NO_EVENTTIMERS 857 sbt >= sbt_timethreshold) { 858 to_sbt = getsbinuptime(); 859 860 /* Add safety belt for the case of hz > 1000. */ 861 to_sbt += tc_tick_sbt - tick_sbt; 862 #else 863 sbt >= sbt_tickthreshold) { 864 /* 865 * Obtain the time of the last hardclock() call on 866 * this CPU directly from the kern_clocksource.c. 867 * This value is per-CPU, but it is equal for all 868 * active ones. 869 */ 870 #ifdef __LP64__ 871 to_sbt = DPCPU_GET(hardclocktime); 872 #else 873 spinlock_enter(); 874 to_sbt = DPCPU_GET(hardclocktime); 875 spinlock_exit(); 876 #endif 877 #endif 878 if (cold && to_sbt == 0) 879 to_sbt = sbinuptime(); 880 if ((flags & C_HARDCLOCK) == 0) 881 to_sbt += tick_sbt; 882 } else 883 to_sbt = sbinuptime(); 884 if (SBT_MAX - to_sbt < sbt) 885 to_sbt = SBT_MAX; 886 else 887 to_sbt += sbt; 888 *res = to_sbt; 889 to_pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : 890 sbt >> C_PRELGET(flags)); 891 *prec_res = to_pr > precision ? to_pr : precision; 892 } 893 894 /* 895 * New interface; clients allocate their own callout structures. 896 * 897 * callout_reset() - establish or change a timeout 898 * callout_stop() - disestablish a timeout 899 * callout_init() - initialize a callout structure so that it can 900 * safely be passed to callout_reset() and callout_stop() 901 * 902 * <sys/callout.h> defines three convenience macros: 903 * 904 * callout_active() - returns truth if callout has not been stopped, 905 * drained, or deactivated since the last time the callout was 906 * reset. 907 * callout_pending() - returns truth if callout is still waiting for timeout 908 * callout_deactivate() - marks the callout as having been serviced 909 */ 910 int 911 callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t prec, 912 callout_func_t *ftn, void *arg, int cpu, int flags) 913 { 914 sbintime_t to_sbt, precision; 915 struct callout_cpu *cc; 916 int cancelled, direct; 917 int ignore_cpu=0; 918 919 cancelled = 0; 920 if (cpu == -1) { 921 ignore_cpu = 1; 922 } else if ((cpu >= MAXCPU) || 923 ((CC_CPU(cpu))->cc_inited == 0)) { 924 /* Invalid CPU spec */ 925 panic("Invalid CPU in callout %d", cpu); 926 } 927 callout_when(sbt, prec, flags, &to_sbt, &precision); 928 929 /* 930 * This flag used to be added by callout_cc_add, but the 931 * first time you call this we could end up with the 932 * wrong direct flag if we don't do it before we add. 933 */ 934 if (flags & C_DIRECT_EXEC) { 935 direct = 1; 936 } else { 937 direct = 0; 938 } 939 KASSERT(!direct || c->c_lock == NULL, 940 ("%s: direct callout %p has lock", __func__, c)); 941 cc = callout_lock(c); 942 /* 943 * Don't allow migration if the user does not care. 944 */ 945 if (ignore_cpu) { 946 cpu = c->c_cpu; 947 } 948 949 if (cc_exec_curr(cc, direct) == c) { 950 /* 951 * We're being asked to reschedule a callout which is 952 * currently in progress. If there is a lock then we 953 * can cancel the callout if it has not really started. 954 */ 955 if (c->c_lock != NULL && !cc_exec_cancel(cc, direct)) 956 cancelled = cc_exec_cancel(cc, direct) = true; 957 if (cc_exec_waiting(cc, direct) || cc_exec_drain(cc, direct)) { 958 /* 959 * Someone has called callout_drain to kill this 960 * callout. Don't reschedule. 961 */ 962 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 963 cancelled ? "cancelled" : "failed to cancel", 964 c, c->c_func, c->c_arg); 965 CC_UNLOCK(cc); 966 return (cancelled); 967 } 968 #ifdef SMP 969 if (callout_migrating(c)) { 970 /* 971 * This only occurs when a second callout_reset_sbt_on 972 * is made after a previous one moved it into 973 * deferred migration (below). Note we do *not* change 974 * the prev_cpu even though the previous target may 975 * be different. 976 */ 977 cc_migration_cpu(cc, direct) = cpu; 978 cc_migration_time(cc, direct) = to_sbt; 979 cc_migration_prec(cc, direct) = precision; 980 cc_migration_func(cc, direct) = ftn; 981 cc_migration_arg(cc, direct) = arg; 982 cancelled = 1; 983 CC_UNLOCK(cc); 984 return (cancelled); 985 } 986 #endif 987 } 988 if (c->c_iflags & CALLOUT_PENDING) { 989 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 990 if (cc_exec_next(cc) == c) 991 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 992 LIST_REMOVE(c, c_links.le); 993 } else { 994 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 995 } 996 cancelled = 1; 997 c->c_iflags &= ~ CALLOUT_PENDING; 998 c->c_flags &= ~ CALLOUT_ACTIVE; 999 } 1000 1001 #ifdef SMP 1002 /* 1003 * If the callout must migrate try to perform it immediately. 1004 * If the callout is currently running, just defer the migration 1005 * to a more appropriate moment. 1006 */ 1007 if (c->c_cpu != cpu) { 1008 if (cc_exec_curr(cc, direct) == c) { 1009 /* 1010 * Pending will have been removed since we are 1011 * actually executing the callout on another 1012 * CPU. That callout should be waiting on the 1013 * lock the caller holds. If we set both 1014 * active/and/pending after we return and the 1015 * lock on the executing callout proceeds, it 1016 * will then see pending is true and return. 1017 * At the return from the actual callout execution 1018 * the migration will occur in softclock_call_cc 1019 * and this new callout will be placed on the 1020 * new CPU via a call to callout_cpu_switch() which 1021 * will get the lock on the right CPU followed 1022 * by a call callout_cc_add() which will add it there. 1023 * (see above in softclock_call_cc()). 1024 */ 1025 cc_migration_cpu(cc, direct) = cpu; 1026 cc_migration_time(cc, direct) = to_sbt; 1027 cc_migration_prec(cc, direct) = precision; 1028 cc_migration_func(cc, direct) = ftn; 1029 cc_migration_arg(cc, direct) = arg; 1030 c->c_iflags |= (CALLOUT_DFRMIGRATION | CALLOUT_PENDING); 1031 c->c_flags |= CALLOUT_ACTIVE; 1032 CTR6(KTR_CALLOUT, 1033 "migration of %p func %p arg %p in %d.%08x to %u deferred", 1034 c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1035 (u_int)(to_sbt & 0xffffffff), cpu); 1036 CC_UNLOCK(cc); 1037 return (cancelled); 1038 } 1039 cc = callout_cpu_switch(c, cc, cpu); 1040 } 1041 #endif 1042 1043 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags); 1044 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", 1045 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1046 (u_int)(to_sbt & 0xffffffff)); 1047 CC_UNLOCK(cc); 1048 1049 return (cancelled); 1050 } 1051 1052 /* 1053 * Common idioms that can be optimized in the future. 1054 */ 1055 int 1056 callout_schedule_on(struct callout *c, int to_ticks, int cpu) 1057 { 1058 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 1059 } 1060 1061 int 1062 callout_schedule(struct callout *c, int to_ticks) 1063 { 1064 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 1065 } 1066 1067 int 1068 _callout_stop_safe(struct callout *c, int flags, callout_func_t *drain) 1069 { 1070 struct callout_cpu *cc, *old_cc; 1071 struct lock_class *class; 1072 int direct, sq_locked, use_lock; 1073 int cancelled, not_on_a_list; 1074 1075 if ((flags & CS_DRAIN) != 0) 1076 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock, 1077 "calling %s", __func__); 1078 1079 /* 1080 * Some old subsystems don't hold Giant while running a callout_stop(), 1081 * so just discard this check for the moment. 1082 */ 1083 if ((flags & CS_DRAIN) == 0 && c->c_lock != NULL) { 1084 if (c->c_lock == &Giant.lock_object) 1085 use_lock = mtx_owned(&Giant); 1086 else { 1087 use_lock = 1; 1088 class = LOCK_CLASS(c->c_lock); 1089 class->lc_assert(c->c_lock, LA_XLOCKED); 1090 } 1091 } else 1092 use_lock = 0; 1093 if (c->c_iflags & CALLOUT_DIRECT) { 1094 direct = 1; 1095 } else { 1096 direct = 0; 1097 } 1098 sq_locked = 0; 1099 old_cc = NULL; 1100 again: 1101 cc = callout_lock(c); 1102 1103 if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) == 1104 (CALLOUT_DFRMIGRATION | CALLOUT_PENDING) && 1105 ((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) { 1106 /* 1107 * Special case where this slipped in while we 1108 * were migrating *as* the callout is about to 1109 * execute. The caller probably holds the lock 1110 * the callout wants. 1111 * 1112 * Get rid of the migration first. Then set 1113 * the flag that tells this code *not* to 1114 * try to remove it from any lists (its not 1115 * on one yet). When the callout wheel runs, 1116 * it will ignore this callout. 1117 */ 1118 c->c_iflags &= ~CALLOUT_PENDING; 1119 c->c_flags &= ~CALLOUT_ACTIVE; 1120 not_on_a_list = 1; 1121 } else { 1122 not_on_a_list = 0; 1123 } 1124 1125 /* 1126 * If the callout was migrating while the callout cpu lock was 1127 * dropped, just drop the sleepqueue lock and check the states 1128 * again. 1129 */ 1130 if (sq_locked != 0 && cc != old_cc) { 1131 #ifdef SMP 1132 CC_UNLOCK(cc); 1133 sleepq_release(&cc_exec_waiting(old_cc, direct)); 1134 sq_locked = 0; 1135 old_cc = NULL; 1136 goto again; 1137 #else 1138 panic("migration should not happen"); 1139 #endif 1140 } 1141 1142 /* 1143 * If the callout is running, try to stop it or drain it. 1144 */ 1145 if (cc_exec_curr(cc, direct) == c) { 1146 /* 1147 * Succeed we to stop it or not, we must clear the 1148 * active flag - this is what API users expect. If we're 1149 * draining and the callout is currently executing, first wait 1150 * until it finishes. 1151 */ 1152 if ((flags & CS_DRAIN) == 0) 1153 c->c_flags &= ~CALLOUT_ACTIVE; 1154 1155 if ((flags & CS_DRAIN) != 0) { 1156 /* 1157 * The current callout is running (or just 1158 * about to run) and blocking is allowed, so 1159 * just wait for the current invocation to 1160 * finish. 1161 */ 1162 while (cc_exec_curr(cc, direct) == c) { 1163 /* 1164 * Use direct calls to sleepqueue interface 1165 * instead of cv/msleep in order to avoid 1166 * a LOR between cc_lock and sleepqueue 1167 * chain spinlocks. This piece of code 1168 * emulates a msleep_spin() call actually. 1169 * 1170 * If we already have the sleepqueue chain 1171 * locked, then we can safely block. If we 1172 * don't already have it locked, however, 1173 * we have to drop the cc_lock to lock 1174 * it. This opens several races, so we 1175 * restart at the beginning once we have 1176 * both locks. If nothing has changed, then 1177 * we will end up back here with sq_locked 1178 * set. 1179 */ 1180 if (!sq_locked) { 1181 CC_UNLOCK(cc); 1182 sleepq_lock( 1183 &cc_exec_waiting(cc, direct)); 1184 sq_locked = 1; 1185 old_cc = cc; 1186 goto again; 1187 } 1188 1189 /* 1190 * Migration could be cancelled here, but 1191 * as long as it is still not sure when it 1192 * will be packed up, just let softclock() 1193 * take care of it. 1194 */ 1195 cc_exec_waiting(cc, direct) = true; 1196 DROP_GIANT(); 1197 CC_UNLOCK(cc); 1198 sleepq_add( 1199 &cc_exec_waiting(cc, direct), 1200 &cc->cc_lock.lock_object, "codrain", 1201 SLEEPQ_SLEEP, 0); 1202 sleepq_wait( 1203 &cc_exec_waiting(cc, direct), 1204 0); 1205 sq_locked = 0; 1206 old_cc = NULL; 1207 1208 /* Reacquire locks previously released. */ 1209 PICKUP_GIANT(); 1210 CC_LOCK(cc); 1211 } 1212 c->c_flags &= ~CALLOUT_ACTIVE; 1213 } else if (use_lock && 1214 !cc_exec_cancel(cc, direct) && (drain == NULL)) { 1215 1216 /* 1217 * The current callout is waiting for its 1218 * lock which we hold. Cancel the callout 1219 * and return. After our caller drops the 1220 * lock, the callout will be skipped in 1221 * softclock(). This *only* works with a 1222 * callout_stop() *not* callout_drain() or 1223 * callout_async_drain(). 1224 */ 1225 cc_exec_cancel(cc, direct) = true; 1226 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1227 c, c->c_func, c->c_arg); 1228 KASSERT(!cc_cce_migrating(cc, direct), 1229 ("callout wrongly scheduled for migration")); 1230 if (callout_migrating(c)) { 1231 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1232 #ifdef SMP 1233 cc_migration_cpu(cc, direct) = CPUBLOCK; 1234 cc_migration_time(cc, direct) = 0; 1235 cc_migration_prec(cc, direct) = 0; 1236 cc_migration_func(cc, direct) = NULL; 1237 cc_migration_arg(cc, direct) = NULL; 1238 #endif 1239 } 1240 CC_UNLOCK(cc); 1241 KASSERT(!sq_locked, ("sleepqueue chain locked")); 1242 return (1); 1243 } else if (callout_migrating(c)) { 1244 /* 1245 * The callout is currently being serviced 1246 * and the "next" callout is scheduled at 1247 * its completion with a migration. We remove 1248 * the migration flag so it *won't* get rescheduled, 1249 * but we can't stop the one thats running so 1250 * we return 0. 1251 */ 1252 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1253 #ifdef SMP 1254 /* 1255 * We can't call cc_cce_cleanup here since 1256 * if we do it will remove .ce_curr and 1257 * its still running. This will prevent a 1258 * reschedule of the callout when the 1259 * execution completes. 1260 */ 1261 cc_migration_cpu(cc, direct) = CPUBLOCK; 1262 cc_migration_time(cc, direct) = 0; 1263 cc_migration_prec(cc, direct) = 0; 1264 cc_migration_func(cc, direct) = NULL; 1265 cc_migration_arg(cc, direct) = NULL; 1266 #endif 1267 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 1268 c, c->c_func, c->c_arg); 1269 if (drain) { 1270 cc_exec_drain(cc, direct) = drain; 1271 } 1272 CC_UNLOCK(cc); 1273 return ((flags & CS_EXECUTING) != 0); 1274 } 1275 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1276 c, c->c_func, c->c_arg); 1277 if (drain) { 1278 cc_exec_drain(cc, direct) = drain; 1279 } 1280 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 1281 cancelled = ((flags & CS_EXECUTING) != 0); 1282 } else 1283 cancelled = 1; 1284 1285 if (sq_locked) 1286 sleepq_release(&cc_exec_waiting(cc, direct)); 1287 1288 if ((c->c_iflags & CALLOUT_PENDING) == 0) { 1289 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1290 c, c->c_func, c->c_arg); 1291 /* 1292 * For not scheduled and not executing callout return 1293 * negative value. 1294 */ 1295 if (cc_exec_curr(cc, direct) != c) 1296 cancelled = -1; 1297 CC_UNLOCK(cc); 1298 return (cancelled); 1299 } 1300 1301 c->c_iflags &= ~CALLOUT_PENDING; 1302 c->c_flags &= ~CALLOUT_ACTIVE; 1303 1304 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1305 c, c->c_func, c->c_arg); 1306 if (not_on_a_list == 0) { 1307 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1308 if (cc_exec_next(cc) == c) 1309 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1310 LIST_REMOVE(c, c_links.le); 1311 } else { 1312 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1313 } 1314 } 1315 CC_UNLOCK(cc); 1316 return (cancelled); 1317 } 1318 1319 void 1320 callout_init(struct callout *c, int mpsafe) 1321 { 1322 bzero(c, sizeof *c); 1323 if (mpsafe) { 1324 c->c_lock = NULL; 1325 c->c_iflags = CALLOUT_RETURNUNLOCKED; 1326 } else { 1327 c->c_lock = &Giant.lock_object; 1328 c->c_iflags = 0; 1329 } 1330 c->c_cpu = cc_default_cpu; 1331 } 1332 1333 void 1334 _callout_init_lock(struct callout *c, struct lock_object *lock, int flags) 1335 { 1336 bzero(c, sizeof *c); 1337 c->c_lock = lock; 1338 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1339 ("callout_init_lock: bad flags %d", flags)); 1340 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1341 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1342 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & 1343 (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class", 1344 __func__)); 1345 c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1346 c->c_cpu = cc_default_cpu; 1347 } 1348 1349 #ifdef APM_FIXUP_CALLTODO 1350 /* 1351 * Adjust the kernel calltodo timeout list. This routine is used after 1352 * an APM resume to recalculate the calltodo timer list values with the 1353 * number of hz's we have been sleeping. The next hardclock() will detect 1354 * that there are fired timers and run softclock() to execute them. 1355 * 1356 * Please note, I have not done an exhaustive analysis of what code this 1357 * might break. I am motivated to have my select()'s and alarm()'s that 1358 * have expired during suspend firing upon resume so that the applications 1359 * which set the timer can do the maintanence the timer was for as close 1360 * as possible to the originally intended time. Testing this code for a 1361 * week showed that resuming from a suspend resulted in 22 to 25 timers 1362 * firing, which seemed independent on whether the suspend was 2 hours or 1363 * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu> 1364 */ 1365 void 1366 adjust_timeout_calltodo(struct timeval *time_change) 1367 { 1368 struct callout *p; 1369 unsigned long delta_ticks; 1370 1371 /* 1372 * How many ticks were we asleep? 1373 * (stolen from tvtohz()). 1374 */ 1375 1376 /* Don't do anything */ 1377 if (time_change->tv_sec < 0) 1378 return; 1379 else if (time_change->tv_sec <= LONG_MAX / 1000000) 1380 delta_ticks = howmany(time_change->tv_sec * 1000000 + 1381 time_change->tv_usec, tick) + 1; 1382 else if (time_change->tv_sec <= LONG_MAX / hz) 1383 delta_ticks = time_change->tv_sec * hz + 1384 howmany(time_change->tv_usec, tick) + 1; 1385 else 1386 delta_ticks = LONG_MAX; 1387 1388 if (delta_ticks > INT_MAX) 1389 delta_ticks = INT_MAX; 1390 1391 /* 1392 * Now rip through the timer calltodo list looking for timers 1393 * to expire. 1394 */ 1395 1396 /* don't collide with softclock() */ 1397 CC_LOCK(cc); 1398 for (p = calltodo.c_next; p != NULL; p = p->c_next) { 1399 p->c_time -= delta_ticks; 1400 1401 /* Break if the timer had more time on it than delta_ticks */ 1402 if (p->c_time > 0) 1403 break; 1404 1405 /* take back the ticks the timer didn't use (p->c_time <= 0) */ 1406 delta_ticks = -p->c_time; 1407 } 1408 CC_UNLOCK(cc); 1409 1410 return; 1411 } 1412 #endif /* APM_FIXUP_CALLTODO */ 1413 1414 static int 1415 flssbt(sbintime_t sbt) 1416 { 1417 1418 sbt += (uint64_t)sbt >> 1; 1419 if (sizeof(long) >= sizeof(sbintime_t)) 1420 return (flsl(sbt)); 1421 if (sbt >= SBT_1S) 1422 return (flsl(((uint64_t)sbt) >> 32) + 32); 1423 return (flsl(sbt)); 1424 } 1425 1426 /* 1427 * Dump immediate statistic snapshot of the scheduled callouts. 1428 */ 1429 static int 1430 sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1431 { 1432 struct callout *tmp; 1433 struct callout_cpu *cc; 1434 struct callout_list *sc; 1435 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; 1436 int ct[64], cpr[64], ccpbk[32]; 1437 int error, val, i, count, tcum, pcum, maxc, c, medc; 1438 int cpu; 1439 1440 val = 0; 1441 error = sysctl_handle_int(oidp, &val, 0, req); 1442 if (error != 0 || req->newptr == NULL) 1443 return (error); 1444 count = maxc = 0; 1445 st = spr = maxt = maxpr = 0; 1446 bzero(ccpbk, sizeof(ccpbk)); 1447 bzero(ct, sizeof(ct)); 1448 bzero(cpr, sizeof(cpr)); 1449 now = sbinuptime(); 1450 CPU_FOREACH(cpu) { 1451 cc = CC_CPU(cpu); 1452 CC_LOCK(cc); 1453 for (i = 0; i < callwheelsize; i++) { 1454 sc = &cc->cc_callwheel[i]; 1455 c = 0; 1456 LIST_FOREACH(tmp, sc, c_links.le) { 1457 c++; 1458 t = tmp->c_time - now; 1459 if (t < 0) 1460 t = 0; 1461 st += t / SBT_1US; 1462 spr += tmp->c_precision / SBT_1US; 1463 if (t > maxt) 1464 maxt = t; 1465 if (tmp->c_precision > maxpr) 1466 maxpr = tmp->c_precision; 1467 ct[flssbt(t)]++; 1468 cpr[flssbt(tmp->c_precision)]++; 1469 } 1470 if (c > maxc) 1471 maxc = c; 1472 ccpbk[fls(c + c / 2)]++; 1473 count += c; 1474 } 1475 CC_UNLOCK(cc); 1476 } 1477 1478 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1479 tcum += ct[i]; 1480 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1481 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) 1482 pcum += cpr[i]; 1483 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1484 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1485 c += ccpbk[i]; 1486 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1487 1488 printf("Scheduled callouts statistic snapshot:\n"); 1489 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1490 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1491 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1492 medc, 1493 count / callwheelsize / mp_ncpus, 1494 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1495 maxc); 1496 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1497 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1498 (st / count) / 1000000, (st / count) % 1000000, 1499 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); 1500 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1501 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, 1502 (spr / count) / 1000000, (spr / count) % 1000000, 1503 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); 1504 printf(" Distribution: \tbuckets\t time\t tcum\t" 1505 " prec\t pcum\n"); 1506 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1507 if (ct[i] == 0 && cpr[i] == 0) 1508 continue; 1509 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1510 tcum += ct[i]; 1511 pcum += cpr[i]; 1512 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", 1513 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1514 i - 1 - (32 - CC_HASH_SHIFT), 1515 ct[i], tcum, cpr[i], pcum); 1516 } 1517 return (error); 1518 } 1519 SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1520 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1521 0, 0, sysctl_kern_callout_stat, "I", 1522 "Dump immediate statistic snapshot of the scheduled callouts"); 1523 1524 #ifdef DDB 1525 static void 1526 _show_callout(struct callout *c) 1527 { 1528 1529 db_printf("callout %p\n", c); 1530 #define C_DB_PRINTF(f, e) db_printf(" %s = " f "\n", #e, c->e); 1531 db_printf(" &c_links = %p\n", &(c->c_links)); 1532 C_DB_PRINTF("%" PRId64, c_time); 1533 C_DB_PRINTF("%" PRId64, c_precision); 1534 C_DB_PRINTF("%p", c_arg); 1535 C_DB_PRINTF("%p", c_func); 1536 C_DB_PRINTF("%p", c_lock); 1537 C_DB_PRINTF("%#x", c_flags); 1538 C_DB_PRINTF("%#x", c_iflags); 1539 C_DB_PRINTF("%d", c_cpu); 1540 #undef C_DB_PRINTF 1541 } 1542 1543 DB_SHOW_COMMAND(callout, db_show_callout) 1544 { 1545 1546 if (!have_addr) { 1547 db_printf("usage: show callout <struct callout *>\n"); 1548 return; 1549 } 1550 1551 _show_callout((struct callout *)addr); 1552 } 1553 1554 static void 1555 _show_last_callout(int cpu, int direct, const char *dirstr) 1556 { 1557 struct callout_cpu *cc; 1558 void *func, *arg; 1559 1560 cc = CC_CPU(cpu); 1561 func = cc_exec_last_func(cc, direct); 1562 arg = cc_exec_last_arg(cc, direct); 1563 db_printf("cpu %d last%s callout function: %p ", cpu, dirstr, func); 1564 db_printsym((db_expr_t)func, DB_STGY_ANY); 1565 db_printf("\ncpu %d last%s callout argument: %p\n", cpu, dirstr, arg); 1566 } 1567 1568 DB_SHOW_COMMAND(callout_last, db_show_callout_last) 1569 { 1570 int cpu, last; 1571 1572 if (have_addr) { 1573 if (addr < 0 || addr > mp_maxid || CPU_ABSENT(addr)) { 1574 db_printf("no such cpu: %d\n", (int)addr); 1575 return; 1576 } 1577 cpu = last = addr; 1578 } else { 1579 cpu = 0; 1580 last = mp_maxid; 1581 } 1582 1583 while (cpu <= last) { 1584 if (!CPU_ABSENT(cpu)) { 1585 _show_last_callout(cpu, 0, ""); 1586 _show_last_callout(cpu, 1, " direct"); 1587 } 1588 cpu++; 1589 } 1590 } 1591 #endif /* DDB */ 1592