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 #include "opt_callout_profiling.h" 41 #include "opt_ddb.h" 42 #include "opt_rss.h" 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/bus.h> 47 #include <sys/callout.h> 48 #include <sys/domainset.h> 49 #include <sys/file.h> 50 #include <sys/interrupt.h> 51 #include <sys/kernel.h> 52 #include <sys/ktr.h> 53 #include <sys/kthread.h> 54 #include <sys/lock.h> 55 #include <sys/malloc.h> 56 #include <sys/mutex.h> 57 #include <sys/proc.h> 58 #include <sys/random.h> 59 #include <sys/sched.h> 60 #include <sys/sdt.h> 61 #include <sys/sleepqueue.h> 62 #include <sys/sysctl.h> 63 #include <sys/smp.h> 64 #include <sys/unistd.h> 65 66 #ifdef DDB 67 #include <ddb/ddb.h> 68 #include <ddb/db_sym.h> 69 #include <machine/_inttypes.h> 70 #endif 71 72 #ifdef SMP 73 #include <machine/cpu.h> 74 #endif 75 76 DPCPU_DECLARE(sbintime_t, hardclocktime); 77 78 SDT_PROVIDER_DEFINE(callout_execute); 79 SDT_PROBE_DEFINE1(callout_execute, , , callout__start, "struct callout *"); 80 SDT_PROBE_DEFINE1(callout_execute, , , callout__end, "struct callout *"); 81 82 static void softclock_thread(void *arg); 83 84 #ifdef CALLOUT_PROFILING 85 static int avg_depth; 86 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, 87 "Average number of items examined per softclock call. Units = 1/1000"); 88 static int avg_gcalls; 89 SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, 90 "Average number of Giant callouts made per softclock call. Units = 1/1000"); 91 static int avg_lockcalls; 92 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0, 93 "Average number of lock callouts made per softclock call. Units = 1/1000"); 94 static int avg_mpcalls; 95 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, 96 "Average number of MP callouts made per softclock call. Units = 1/1000"); 97 static int avg_depth_dir; 98 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0, 99 "Average number of direct callouts examined per callout_process call. " 100 "Units = 1/1000"); 101 static int avg_lockcalls_dir; 102 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD, 103 &avg_lockcalls_dir, 0, "Average number of lock direct callouts made per " 104 "callout_process call. Units = 1/1000"); 105 static int avg_mpcalls_dir; 106 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir, 107 0, "Average number of MP direct callouts made per callout_process call. " 108 "Units = 1/1000"); 109 #endif 110 111 static int ncallout; 112 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &ncallout, 0, 113 "Number of entries in callwheel and size of timeout() preallocation"); 114 115 #ifdef RSS 116 static int pin_default_swi = 1; 117 static int pin_pcpu_swi = 1; 118 #else 119 static int pin_default_swi = 0; 120 static int pin_pcpu_swi = 0; 121 #endif 122 123 SYSCTL_INT(_kern, OID_AUTO, pin_default_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_default_swi, 124 0, "Pin the default (non-per-cpu) swi (shared with PCPU 0 swi)"); 125 SYSCTL_INT(_kern, OID_AUTO, pin_pcpu_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_pcpu_swi, 126 0, "Pin the per-CPU swis (except PCPU 0, which is also default)"); 127 128 /* 129 * TODO: 130 * allocate more timeout table slots when table overflows. 131 */ 132 static u_int __read_mostly callwheelsize; 133 static u_int __read_mostly callwheelmask; 134 135 /* 136 * The callout cpu exec entities represent informations necessary for 137 * describing the state of callouts currently running on the CPU and the ones 138 * necessary for migrating callouts to the new callout cpu. In particular, 139 * the first entry of the array cc_exec_entity holds informations for callout 140 * running in SWI thread context, while the second one holds informations 141 * for callout running directly from hardware interrupt context. 142 * The cached informations are very important for deferring migration when 143 * the migrating callout is already running. 144 */ 145 struct cc_exec { 146 struct callout *cc_curr; 147 callout_func_t *cc_drain; 148 void *cc_last_func; 149 void *cc_last_arg; 150 #ifdef SMP 151 callout_func_t *ce_migration_func; 152 void *ce_migration_arg; 153 sbintime_t ce_migration_time; 154 sbintime_t ce_migration_prec; 155 int ce_migration_cpu; 156 #endif 157 bool cc_cancel; 158 bool cc_waiting; 159 }; 160 161 /* 162 * There is one struct callout_cpu per cpu, holding all relevant 163 * state for the callout processing thread on the individual CPU. 164 */ 165 struct callout_cpu { 166 struct mtx_padalign cc_lock; 167 struct cc_exec cc_exec_entity[2]; 168 struct callout *cc_next; 169 struct callout_list *cc_callwheel; 170 struct callout_tailq cc_expireq; 171 sbintime_t cc_firstevent; 172 sbintime_t cc_lastscan; 173 struct thread *cc_thread; 174 u_int cc_bucket; 175 #ifdef KTR 176 char cc_ktr_event_name[20]; 177 #endif 178 }; 179 180 #define callout_migrating(c) ((c)->c_iflags & CALLOUT_DFRMIGRATION) 181 182 #define cc_exec_curr(cc, dir) cc->cc_exec_entity[dir].cc_curr 183 #define cc_exec_last_func(cc, dir) cc->cc_exec_entity[dir].cc_last_func 184 #define cc_exec_last_arg(cc, dir) cc->cc_exec_entity[dir].cc_last_arg 185 #define cc_exec_drain(cc, dir) cc->cc_exec_entity[dir].cc_drain 186 #define cc_exec_next(cc) cc->cc_next 187 #define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel 188 #define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting 189 #ifdef SMP 190 #define cc_migration_func(cc, dir) cc->cc_exec_entity[dir].ce_migration_func 191 #define cc_migration_arg(cc, dir) cc->cc_exec_entity[dir].ce_migration_arg 192 #define cc_migration_cpu(cc, dir) cc->cc_exec_entity[dir].ce_migration_cpu 193 #define cc_migration_time(cc, dir) cc->cc_exec_entity[dir].ce_migration_time 194 #define cc_migration_prec(cc, dir) cc->cc_exec_entity[dir].ce_migration_prec 195 196 DPCPU_DEFINE_STATIC(struct callout_cpu, cc_cpu); 197 #define CPUBLOCK MAXCPU 198 #define CC_CPU(cpu) DPCPU_ID_PTR(cpu, cc_cpu) 199 #define CC_SELF() CC_CPU(PCPU_GET(cpuid)) 200 #else 201 static struct callout_cpu cc_cpu; 202 #define CC_CPU(cpu) (&cc_cpu) 203 #define CC_SELF() (&cc_cpu) 204 #endif 205 #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) 206 #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) 207 #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) 208 209 static int __read_mostly cc_default_cpu; 210 211 static void callout_cpu_init(struct callout_cpu *cc, int cpu); 212 static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, 213 #ifdef CALLOUT_PROFILING 214 int *mpcalls, int *lockcalls, int *gcalls, 215 #endif 216 int direct); 217 218 static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); 219 220 /** 221 * Locked by cc_lock: 222 * cc_curr - If a callout is in progress, it is cc_curr. 223 * If cc_curr is non-NULL, threads waiting in 224 * callout_drain() will be woken up as soon as the 225 * relevant callout completes. 226 * cc_cancel - Changing to 1 with both callout_lock and cc_lock held 227 * guarantees that the current callout will not run. 228 * The softclock_call_cc() function sets this to 0 before it 229 * drops callout_lock to acquire c_lock, and it calls 230 * the handler only if curr_cancelled is still 0 after 231 * cc_lock is successfully acquired. 232 * cc_waiting - If a thread is waiting in callout_drain(), then 233 * callout_wait is nonzero. Set only when 234 * cc_curr is non-NULL. 235 */ 236 237 /* 238 * Resets the execution entity tied to a specific callout cpu. 239 */ 240 static void 241 cc_cce_cleanup(struct callout_cpu *cc, int direct) 242 { 243 244 cc_exec_curr(cc, direct) = NULL; 245 cc_exec_cancel(cc, direct) = false; 246 cc_exec_waiting(cc, direct) = false; 247 #ifdef SMP 248 cc_migration_cpu(cc, direct) = CPUBLOCK; 249 cc_migration_time(cc, direct) = 0; 250 cc_migration_prec(cc, direct) = 0; 251 cc_migration_func(cc, direct) = NULL; 252 cc_migration_arg(cc, direct) = NULL; 253 #endif 254 } 255 256 /* 257 * Checks if migration is requested by a specific callout cpu. 258 */ 259 static int 260 cc_cce_migrating(struct callout_cpu *cc, int direct) 261 { 262 263 #ifdef SMP 264 return (cc_migration_cpu(cc, direct) != CPUBLOCK); 265 #else 266 return (0); 267 #endif 268 } 269 270 /* 271 * Kernel low level callwheel initialization 272 * called on the BSP during kernel startup. 273 */ 274 static void 275 callout_callwheel_init(void *dummy) 276 { 277 struct callout_cpu *cc; 278 int cpu; 279 280 /* 281 * Calculate the size of the callout wheel and the preallocated 282 * timeout() structures. 283 * XXX: Clip callout to result of previous function of maxusers 284 * maximum 384. This is still huge, but acceptable. 285 */ 286 ncallout = imin(16 + maxproc + maxfiles, 18508); 287 TUNABLE_INT_FETCH("kern.ncallout", &ncallout); 288 289 /* 290 * Calculate callout wheel size, should be next power of two higher 291 * than 'ncallout'. 292 */ 293 callwheelsize = 1 << fls(ncallout); 294 callwheelmask = callwheelsize - 1; 295 296 /* 297 * Fetch whether we're pinning the swi's or not. 298 */ 299 TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi); 300 TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi); 301 302 /* 303 * Initialize callout wheels. The software interrupt threads 304 * are created later. 305 */ 306 cc_default_cpu = PCPU_GET(cpuid); 307 CPU_FOREACH(cpu) { 308 cc = CC_CPU(cpu); 309 callout_cpu_init(cc, cpu); 310 } 311 } 312 SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); 313 314 /* 315 * Initialize the per-cpu callout structures. 316 */ 317 static void 318 callout_cpu_init(struct callout_cpu *cc, int cpu) 319 { 320 int i; 321 322 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN); 323 cc->cc_callwheel = malloc_domainset(sizeof(struct callout_list) * 324 callwheelsize, M_CALLOUT, 325 DOMAINSET_PREF(pcpu_find(cpu)->pc_domain), M_WAITOK); 326 for (i = 0; i < callwheelsize; i++) 327 LIST_INIT(&cc->cc_callwheel[i]); 328 TAILQ_INIT(&cc->cc_expireq); 329 cc->cc_firstevent = SBT_MAX; 330 for (i = 0; i < 2; i++) 331 cc_cce_cleanup(cc, i); 332 #ifdef KTR 333 snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name), 334 "callwheel cpu %d", cpu); 335 #endif 336 } 337 338 #ifdef SMP 339 /* 340 * Switches the cpu tied to a specific callout. 341 * The function expects a locked incoming callout cpu and returns with 342 * locked outcoming callout cpu. 343 */ 344 static struct callout_cpu * 345 callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu) 346 { 347 struct callout_cpu *new_cc; 348 349 MPASS(c != NULL && cc != NULL); 350 CC_LOCK_ASSERT(cc); 351 352 /* 353 * Avoid interrupts and preemption firing after the callout cpu 354 * is blocked in order to avoid deadlocks as the new thread 355 * may be willing to acquire the callout cpu lock. 356 */ 357 c->c_cpu = CPUBLOCK; 358 spinlock_enter(); 359 CC_UNLOCK(cc); 360 new_cc = CC_CPU(new_cpu); 361 CC_LOCK(new_cc); 362 spinlock_exit(); 363 c->c_cpu = new_cpu; 364 return (new_cc); 365 } 366 #endif 367 368 /* 369 * Start softclock threads. 370 */ 371 static void 372 start_softclock(void *dummy) 373 { 374 struct proc *p; 375 struct thread *td; 376 struct callout_cpu *cc; 377 int cpu, error; 378 bool pin_swi; 379 380 p = NULL; 381 CPU_FOREACH(cpu) { 382 cc = CC_CPU(cpu); 383 error = kproc_kthread_add(softclock_thread, cc, &p, &td, 384 RFSTOPPED, 0, "clock", "clock (%d)", cpu); 385 if (error != 0) 386 panic("failed to create softclock thread for cpu %d: %d", 387 cpu, error); 388 CC_LOCK(cc); 389 cc->cc_thread = td; 390 thread_lock(td); 391 sched_class(td, PRI_ITHD); 392 sched_ithread_prio(td, PI_SOFTCLOCK); 393 TD_SET_IWAIT(td); 394 thread_lock_set(td, (struct mtx *)&cc->cc_lock); 395 thread_unlock(td); 396 if (cpu == cc_default_cpu) 397 pin_swi = pin_default_swi; 398 else 399 pin_swi = pin_pcpu_swi; 400 if (pin_swi) { 401 error = cpuset_setithread(td->td_tid, cpu); 402 if (error != 0) 403 printf("%s: %s clock couldn't be pinned to cpu %d: %d\n", 404 __func__, cpu == cc_default_cpu ? 405 "default" : "per-cpu", cpu, error); 406 } 407 } 408 } 409 SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); 410 411 #define CC_HASH_SHIFT 8 412 413 static inline u_int 414 callout_hash(sbintime_t sbt) 415 { 416 417 return (sbt >> (32 - CC_HASH_SHIFT)); 418 } 419 420 static inline u_int 421 callout_get_bucket(sbintime_t sbt) 422 { 423 424 return (callout_hash(sbt) & callwheelmask); 425 } 426 427 void 428 callout_process(sbintime_t now) 429 { 430 struct callout_entropy { 431 struct callout_cpu *cc; 432 struct thread *td; 433 sbintime_t now; 434 } entropy; 435 struct callout *c, *next; 436 struct callout_cpu *cc; 437 struct callout_list *sc; 438 struct thread *td; 439 sbintime_t first, last, lookahead, max, tmp_max; 440 u_int firstb, lastb, nowb; 441 #ifdef CALLOUT_PROFILING 442 int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0; 443 #endif 444 445 cc = CC_SELF(); 446 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET); 447 448 /* Compute the buckets of the last scan and present times. */ 449 firstb = callout_hash(cc->cc_lastscan); 450 cc->cc_lastscan = now; 451 nowb = callout_hash(now); 452 453 /* Compute the last bucket and minimum time of the bucket after it. */ 454 if (nowb == firstb) 455 lookahead = (SBT_1S / 16); 456 else if (nowb - firstb == 1) 457 lookahead = (SBT_1S / 8); 458 else 459 lookahead = SBT_1S; 460 first = last = now; 461 first += (lookahead / 2); 462 last += lookahead; 463 last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); 464 lastb = callout_hash(last) - 1; 465 max = last; 466 467 /* 468 * Check if we wrapped around the entire wheel from the last scan. 469 * In case, we need to scan entirely the wheel for pending callouts. 470 */ 471 if (lastb - firstb >= callwheelsize) { 472 lastb = firstb + callwheelsize - 1; 473 if (nowb - firstb >= callwheelsize) 474 nowb = lastb; 475 } 476 477 /* Iterate callwheel from firstb to nowb and then up to lastb. */ 478 do { 479 sc = &cc->cc_callwheel[firstb & callwheelmask]; 480 LIST_FOREACH_SAFE(c, sc, c_links.le, next) { 481 /* Run the callout if present time within allowed. */ 482 if (c->c_time <= now) { 483 /* 484 * Consumer told us the callout may be run 485 * directly from hardware interrupt context. 486 */ 487 if (c->c_iflags & CALLOUT_DIRECT) { 488 #ifdef CALLOUT_PROFILING 489 ++depth_dir; 490 #endif 491 cc_exec_next(cc) = next; 492 cc->cc_bucket = firstb & callwheelmask; 493 LIST_REMOVE(c, c_links.le); 494 softclock_call_cc(c, cc, 495 #ifdef CALLOUT_PROFILING 496 &mpcalls_dir, &lockcalls_dir, NULL, 497 #endif 498 1); 499 next = cc_exec_next(cc); 500 cc_exec_next(cc) = NULL; 501 } else { 502 LIST_REMOVE(c, c_links.le); 503 TAILQ_INSERT_TAIL(&cc->cc_expireq, 504 c, c_links.tqe); 505 c->c_iflags |= CALLOUT_PROCESSED; 506 } 507 } else if (c->c_time >= max) { 508 /* 509 * Skip events in the distant future. 510 */ 511 ; 512 } else if (c->c_time > last) { 513 /* 514 * Event minimal time is bigger than present 515 * maximal time, so it cannot be aggregated. 516 */ 517 lastb = nowb; 518 } else { 519 /* 520 * Update first and last time, respecting this 521 * event. 522 */ 523 if (c->c_time < first) 524 first = c->c_time; 525 tmp_max = c->c_time + c->c_precision; 526 if (tmp_max < last) 527 last = tmp_max; 528 } 529 } 530 /* Proceed with the next bucket. */ 531 firstb++; 532 /* 533 * Stop if we looked after present time and found 534 * some event we can't execute at now. 535 * Stop if we looked far enough into the future. 536 */ 537 } while (((int)(firstb - lastb)) <= 0); 538 cc->cc_firstevent = last; 539 cpu_new_callout(curcpu, last, first); 540 541 #ifdef CALLOUT_PROFILING 542 avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8; 543 avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8; 544 avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8; 545 #endif 546 if (!TAILQ_EMPTY(&cc->cc_expireq)) { 547 entropy.cc = cc; 548 entropy.td = curthread; 549 entropy.now = now; 550 random_harvest_queue(&entropy, sizeof(entropy), RANDOM_CALLOUT); 551 552 td = cc->cc_thread; 553 if (TD_AWAITING_INTR(td)) { 554 thread_lock_block_wait(td); 555 THREAD_LOCK_ASSERT(td, MA_OWNED); 556 TD_CLR_IWAIT(td); 557 sched_wakeup(td, SRQ_INTR); 558 } else 559 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 560 } else 561 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 562 } 563 564 static struct callout_cpu * 565 callout_lock(struct callout *c) 566 { 567 struct callout_cpu *cc; 568 int cpu; 569 570 for (;;) { 571 cpu = c->c_cpu; 572 #ifdef SMP 573 if (cpu == CPUBLOCK) { 574 while (c->c_cpu == CPUBLOCK) 575 cpu_spinwait(); 576 continue; 577 } 578 #endif 579 cc = CC_CPU(cpu); 580 CC_LOCK(cc); 581 if (cpu == c->c_cpu) 582 break; 583 CC_UNLOCK(cc); 584 } 585 return (cc); 586 } 587 588 static void 589 callout_cc_add(struct callout *c, struct callout_cpu *cc, 590 sbintime_t sbt, sbintime_t precision, void (*func)(void *), 591 void *arg, int flags) 592 { 593 int bucket; 594 595 CC_LOCK_ASSERT(cc); 596 if (sbt < cc->cc_lastscan) 597 sbt = cc->cc_lastscan; 598 c->c_arg = arg; 599 c->c_iflags |= CALLOUT_PENDING; 600 c->c_iflags &= ~CALLOUT_PROCESSED; 601 c->c_flags |= CALLOUT_ACTIVE; 602 if (flags & C_DIRECT_EXEC) 603 c->c_iflags |= CALLOUT_DIRECT; 604 c->c_func = func; 605 c->c_time = sbt; 606 c->c_precision = precision; 607 bucket = callout_get_bucket(c->c_time); 608 CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x", 609 c, (int)(c->c_precision >> 32), 610 (u_int)(c->c_precision & 0xffffffff)); 611 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); 612 if (cc->cc_bucket == bucket) 613 cc_exec_next(cc) = c; 614 615 /* 616 * Inform the eventtimers(4) subsystem there's a new callout 617 * that has been inserted, but only if really required. 618 */ 619 if (SBT_MAX - c->c_time < c->c_precision) 620 c->c_precision = SBT_MAX - c->c_time; 621 sbt = c->c_time + c->c_precision; 622 if (sbt < cc->cc_firstevent) { 623 cc->cc_firstevent = sbt; 624 cpu_new_callout(c->c_cpu, sbt, c->c_time); 625 } 626 } 627 628 static void 629 softclock_call_cc(struct callout *c, struct callout_cpu *cc, 630 #ifdef CALLOUT_PROFILING 631 int *mpcalls, int *lockcalls, int *gcalls, 632 #endif 633 int direct) 634 { 635 struct rm_priotracker tracker; 636 callout_func_t *c_func, *drain; 637 void *c_arg; 638 struct lock_class *class; 639 struct lock_object *c_lock; 640 uintptr_t lock_status; 641 int c_iflags; 642 #ifdef SMP 643 struct callout_cpu *new_cc; 644 callout_func_t *new_func; 645 void *new_arg; 646 int flags, new_cpu; 647 sbintime_t new_prec, new_time; 648 #endif 649 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 650 sbintime_t sbt1, sbt2; 651 struct timespec ts2; 652 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 653 static callout_func_t *lastfunc; 654 #endif 655 656 KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING, 657 ("softclock_call_cc: pend %p %x", c, c->c_iflags)); 658 KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE, 659 ("softclock_call_cc: act %p %x", c, c->c_flags)); 660 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; 661 lock_status = 0; 662 if (c->c_iflags & CALLOUT_SHAREDLOCK) { 663 if (class == &lock_class_rm) 664 lock_status = (uintptr_t)&tracker; 665 else 666 lock_status = 1; 667 } 668 c_lock = c->c_lock; 669 c_func = c->c_func; 670 c_arg = c->c_arg; 671 c_iflags = c->c_iflags; 672 c->c_iflags &= ~CALLOUT_PENDING; 673 674 cc_exec_curr(cc, direct) = c; 675 cc_exec_last_func(cc, direct) = c_func; 676 cc_exec_last_arg(cc, direct) = c_arg; 677 cc_exec_cancel(cc, direct) = false; 678 cc_exec_drain(cc, direct) = NULL; 679 CC_UNLOCK(cc); 680 if (c_lock != NULL) { 681 class->lc_lock(c_lock, lock_status); 682 /* 683 * The callout may have been cancelled 684 * while we switched locks. 685 */ 686 if (cc_exec_cancel(cc, direct)) { 687 class->lc_unlock(c_lock); 688 goto skip; 689 } 690 /* The callout cannot be stopped now. */ 691 cc_exec_cancel(cc, direct) = true; 692 if (c_lock == &Giant.lock_object) { 693 #ifdef CALLOUT_PROFILING 694 (*gcalls)++; 695 #endif 696 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", 697 c, c_func, c_arg); 698 } else { 699 #ifdef CALLOUT_PROFILING 700 (*lockcalls)++; 701 #endif 702 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", 703 c, c_func, c_arg); 704 } 705 } else { 706 #ifdef CALLOUT_PROFILING 707 (*mpcalls)++; 708 #endif 709 CTR3(KTR_CALLOUT, "callout %p func %p arg %p", 710 c, c_func, c_arg); 711 } 712 KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running", 713 "func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct); 714 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 715 sbt1 = sbinuptime(); 716 #endif 717 THREAD_NO_SLEEPING(); 718 SDT_PROBE1(callout_execute, , , callout__start, c); 719 c_func(c_arg); 720 SDT_PROBE1(callout_execute, , , callout__end, c); 721 THREAD_SLEEPING_OK(); 722 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 723 sbt2 = sbinuptime(); 724 sbt2 -= sbt1; 725 if (sbt2 > maxdt) { 726 if (lastfunc != c_func || sbt2 > maxdt * 2) { 727 ts2 = sbttots(sbt2); 728 printf( 729 "Expensive callout(9) function: %p(%p) %jd.%09ld s\n", 730 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); 731 } 732 maxdt = sbt2; 733 lastfunc = c_func; 734 } 735 #endif 736 KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle"); 737 CTR1(KTR_CALLOUT, "callout %p finished", c); 738 if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0) 739 class->lc_unlock(c_lock); 740 skip: 741 CC_LOCK(cc); 742 KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr")); 743 cc_exec_curr(cc, direct) = NULL; 744 if (cc_exec_drain(cc, direct)) { 745 drain = cc_exec_drain(cc, direct); 746 cc_exec_drain(cc, direct) = NULL; 747 CC_UNLOCK(cc); 748 drain(c_arg); 749 CC_LOCK(cc); 750 } 751 if (cc_exec_waiting(cc, direct)) { 752 /* 753 * There is someone waiting for the 754 * callout to complete. 755 * If the callout was scheduled for 756 * migration just cancel it. 757 */ 758 if (cc_cce_migrating(cc, direct)) { 759 cc_cce_cleanup(cc, direct); 760 761 /* 762 * It should be assert here that the callout is not 763 * destroyed but that is not easy. 764 */ 765 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 766 } 767 cc_exec_waiting(cc, direct) = false; 768 CC_UNLOCK(cc); 769 wakeup(&cc_exec_waiting(cc, direct)); 770 CC_LOCK(cc); 771 } else if (cc_cce_migrating(cc, direct)) { 772 #ifdef SMP 773 /* 774 * If the callout was scheduled for 775 * migration just perform it now. 776 */ 777 new_cpu = cc_migration_cpu(cc, direct); 778 new_time = cc_migration_time(cc, direct); 779 new_prec = cc_migration_prec(cc, direct); 780 new_func = cc_migration_func(cc, direct); 781 new_arg = cc_migration_arg(cc, direct); 782 cc_cce_cleanup(cc, direct); 783 784 /* 785 * It should be assert here that the callout is not destroyed 786 * but that is not easy. 787 * 788 * As first thing, handle deferred callout stops. 789 */ 790 if (!callout_migrating(c)) { 791 CTR3(KTR_CALLOUT, 792 "deferred cancelled %p func %p arg %p", 793 c, new_func, new_arg); 794 return; 795 } 796 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 797 798 new_cc = callout_cpu_switch(c, cc, new_cpu); 799 flags = (direct) ? C_DIRECT_EXEC : 0; 800 callout_cc_add(c, new_cc, new_time, new_prec, new_func, 801 new_arg, flags); 802 CC_UNLOCK(new_cc); 803 CC_LOCK(cc); 804 #else 805 panic("migration should not happen"); 806 #endif 807 } 808 } 809 810 /* 811 * The callout mechanism is based on the work of Adam M. Costello and 812 * George Varghese, published in a technical report entitled "Redesigning 813 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 814 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 815 * used in this implementation was published by G. Varghese and T. Lauck in 816 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 817 * the Efficient Implementation of a Timer Facility" in the Proceedings of 818 * the 11th ACM Annual Symposium on Operating Systems Principles, 819 * Austin, Texas Nov 1987. 820 */ 821 822 /* 823 * Software (low priority) clock interrupt thread handler. 824 * Run periodic events from timeout queue. 825 */ 826 static void 827 softclock_thread(void *arg) 828 { 829 struct thread *td = curthread; 830 struct callout_cpu *cc; 831 struct callout *c; 832 #ifdef CALLOUT_PROFILING 833 int depth, gcalls, lockcalls, mpcalls; 834 #endif 835 836 cc = (struct callout_cpu *)arg; 837 CC_LOCK(cc); 838 for (;;) { 839 while (TAILQ_EMPTY(&cc->cc_expireq)) { 840 /* 841 * Use CC_LOCK(cc) as the thread_lock while 842 * idle. 843 */ 844 thread_lock(td); 845 thread_lock_set(td, (struct mtx *)&cc->cc_lock); 846 TD_SET_IWAIT(td); 847 mi_switch(SW_VOL | SWT_IWAIT); 848 849 /* mi_switch() drops thread_lock(). */ 850 CC_LOCK(cc); 851 } 852 853 #ifdef CALLOUT_PROFILING 854 depth = gcalls = lockcalls = mpcalls = 0; 855 #endif 856 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { 857 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 858 softclock_call_cc(c, cc, 859 #ifdef CALLOUT_PROFILING 860 &mpcalls, &lockcalls, &gcalls, 861 #endif 862 0); 863 #ifdef CALLOUT_PROFILING 864 ++depth; 865 #endif 866 } 867 #ifdef CALLOUT_PROFILING 868 avg_depth += (depth * 1000 - avg_depth) >> 8; 869 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 870 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 871 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 872 #endif 873 } 874 } 875 876 void 877 callout_when(sbintime_t sbt, sbintime_t precision, int flags, 878 sbintime_t *res, sbintime_t *prec_res) 879 { 880 sbintime_t to_sbt, to_pr; 881 882 if ((flags & (C_ABSOLUTE | C_PRECALC)) != 0) { 883 *res = sbt; 884 *prec_res = precision; 885 return; 886 } 887 if ((flags & C_HARDCLOCK) != 0 && sbt < tick_sbt) 888 sbt = tick_sbt; 889 if ((flags & C_HARDCLOCK) != 0 || sbt >= sbt_tickthreshold) { 890 /* 891 * Obtain the time of the last hardclock() call on 892 * this CPU directly from the kern_clocksource.c. 893 * This value is per-CPU, but it is equal for all 894 * active ones. 895 */ 896 #ifdef __LP64__ 897 to_sbt = DPCPU_GET(hardclocktime); 898 #else 899 spinlock_enter(); 900 to_sbt = DPCPU_GET(hardclocktime); 901 spinlock_exit(); 902 #endif 903 if (cold && to_sbt == 0) 904 to_sbt = sbinuptime(); 905 if ((flags & C_HARDCLOCK) == 0) 906 to_sbt += tick_sbt; 907 } else 908 to_sbt = sbinuptime(); 909 if (SBT_MAX - to_sbt < sbt) 910 to_sbt = SBT_MAX; 911 else 912 to_sbt += sbt; 913 *res = to_sbt; 914 to_pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : 915 sbt >> C_PRELGET(flags)); 916 *prec_res = to_pr > precision ? to_pr : precision; 917 } 918 919 /* 920 * New interface; clients allocate their own callout structures. 921 * 922 * callout_reset() - establish or change a timeout 923 * callout_stop() - disestablish a timeout 924 * callout_init() - initialize a callout structure so that it can 925 * safely be passed to callout_reset() and callout_stop() 926 * 927 * <sys/callout.h> defines three convenience macros: 928 * 929 * callout_active() - returns truth if callout has not been stopped, 930 * drained, or deactivated since the last time the callout was 931 * reset. 932 * callout_pending() - returns truth if callout is still waiting for timeout 933 * callout_deactivate() - marks the callout as having been serviced 934 */ 935 int 936 callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t prec, 937 callout_func_t *ftn, void *arg, int cpu, int flags) 938 { 939 sbintime_t to_sbt, precision; 940 struct callout_cpu *cc; 941 int cancelled, direct; 942 943 cancelled = 0; 944 callout_when(sbt, prec, flags, &to_sbt, &precision); 945 946 /* 947 * This flag used to be added by callout_cc_add, but the 948 * first time you call this we could end up with the 949 * wrong direct flag if we don't do it before we add. 950 */ 951 if (flags & C_DIRECT_EXEC) { 952 direct = 1; 953 } else { 954 direct = 0; 955 } 956 KASSERT(!direct || c->c_lock == NULL || 957 (LOCK_CLASS(c->c_lock)->lc_flags & LC_SPINLOCK), 958 ("%s: direct callout %p has non-spin lock", __func__, c)); 959 960 cc = callout_lock(c); 961 if (cpu == -1) 962 cpu = c->c_cpu; 963 KASSERT(cpu >= 0 && cpu <= mp_maxid && !CPU_ABSENT(cpu), 964 ("%s: invalid cpu %d", __func__, cpu)); 965 966 if (cc_exec_curr(cc, direct) == c) { 967 /* 968 * We're being asked to reschedule a callout which is 969 * currently in progress. If there is a lock then we 970 * can cancel the callout if it has not really started. 971 */ 972 if (c->c_lock != NULL && !cc_exec_cancel(cc, direct)) 973 cancelled = cc_exec_cancel(cc, direct) = true; 974 if (cc_exec_waiting(cc, direct) || cc_exec_drain(cc, direct)) { 975 /* 976 * Someone has called callout_drain to kill this 977 * callout. Don't reschedule. 978 */ 979 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 980 cancelled ? "cancelled" : "failed to cancel", 981 c, c->c_func, c->c_arg); 982 CC_UNLOCK(cc); 983 return (cancelled); 984 } 985 #ifdef SMP 986 if (callout_migrating(c)) { 987 /* 988 * This only occurs when a second callout_reset_sbt_on 989 * is made after a previous one moved it into 990 * deferred migration (below). Note we do *not* change 991 * the prev_cpu even though the previous target may 992 * be different. 993 */ 994 cc_migration_cpu(cc, direct) = cpu; 995 cc_migration_time(cc, direct) = to_sbt; 996 cc_migration_prec(cc, direct) = precision; 997 cc_migration_func(cc, direct) = ftn; 998 cc_migration_arg(cc, direct) = arg; 999 cancelled = 1; 1000 CC_UNLOCK(cc); 1001 return (cancelled); 1002 } 1003 #endif 1004 } 1005 if (c->c_iflags & CALLOUT_PENDING) { 1006 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1007 if (cc_exec_next(cc) == c) 1008 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1009 LIST_REMOVE(c, c_links.le); 1010 } else { 1011 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1012 } 1013 cancelled = 1; 1014 c->c_iflags &= ~ CALLOUT_PENDING; 1015 c->c_flags &= ~ CALLOUT_ACTIVE; 1016 } 1017 1018 #ifdef SMP 1019 /* 1020 * If the callout must migrate try to perform it immediately. 1021 * If the callout is currently running, just defer the migration 1022 * to a more appropriate moment. 1023 */ 1024 if (c->c_cpu != cpu) { 1025 if (cc_exec_curr(cc, direct) == c) { 1026 /* 1027 * Pending will have been removed since we are 1028 * actually executing the callout on another 1029 * CPU. That callout should be waiting on the 1030 * lock the caller holds. If we set both 1031 * active/and/pending after we return and the 1032 * lock on the executing callout proceeds, it 1033 * will then see pending is true and return. 1034 * At the return from the actual callout execution 1035 * the migration will occur in softclock_call_cc 1036 * and this new callout will be placed on the 1037 * new CPU via a call to callout_cpu_switch() which 1038 * will get the lock on the right CPU followed 1039 * by a call callout_cc_add() which will add it there. 1040 * (see above in softclock_call_cc()). 1041 */ 1042 cc_migration_cpu(cc, direct) = cpu; 1043 cc_migration_time(cc, direct) = to_sbt; 1044 cc_migration_prec(cc, direct) = precision; 1045 cc_migration_func(cc, direct) = ftn; 1046 cc_migration_arg(cc, direct) = arg; 1047 c->c_iflags |= (CALLOUT_DFRMIGRATION | CALLOUT_PENDING); 1048 c->c_flags |= CALLOUT_ACTIVE; 1049 CTR6(KTR_CALLOUT, 1050 "migration of %p func %p arg %p in %d.%08x to %u deferred", 1051 c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1052 (u_int)(to_sbt & 0xffffffff), cpu); 1053 CC_UNLOCK(cc); 1054 return (cancelled); 1055 } 1056 cc = callout_cpu_switch(c, cc, cpu); 1057 } 1058 #endif 1059 1060 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, flags); 1061 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", 1062 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1063 (u_int)(to_sbt & 0xffffffff)); 1064 CC_UNLOCK(cc); 1065 1066 return (cancelled); 1067 } 1068 1069 /* 1070 * Common idioms that can be optimized in the future. 1071 */ 1072 int 1073 callout_schedule_on(struct callout *c, int to_ticks, int cpu) 1074 { 1075 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 1076 } 1077 1078 int 1079 callout_schedule(struct callout *c, int to_ticks) 1080 { 1081 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 1082 } 1083 1084 int 1085 _callout_stop_safe(struct callout *c, int flags, callout_func_t *drain) 1086 { 1087 struct callout_cpu *cc, *old_cc; 1088 struct lock_class *class; 1089 int direct, sq_locked, use_lock; 1090 int cancelled, not_on_a_list; 1091 1092 if ((flags & CS_DRAIN) != 0) 1093 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock, 1094 "calling %s", __func__); 1095 1096 KASSERT((flags & CS_DRAIN) == 0 || drain == NULL, 1097 ("Cannot set drain callback and CS_DRAIN flag at the same time")); 1098 1099 /* 1100 * Some old subsystems don't hold Giant while running a callout_stop(), 1101 * so just discard this check for the moment. 1102 */ 1103 if ((flags & CS_DRAIN) == 0 && c->c_lock != NULL) { 1104 if (c->c_lock == &Giant.lock_object) 1105 use_lock = mtx_owned(&Giant); 1106 else { 1107 use_lock = 1; 1108 class = LOCK_CLASS(c->c_lock); 1109 class->lc_assert(c->c_lock, LA_XLOCKED); 1110 } 1111 } else 1112 use_lock = 0; 1113 if (c->c_iflags & CALLOUT_DIRECT) { 1114 direct = 1; 1115 } else { 1116 direct = 0; 1117 } 1118 sq_locked = 0; 1119 old_cc = NULL; 1120 again: 1121 cc = callout_lock(c); 1122 1123 if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) == 1124 (CALLOUT_DFRMIGRATION | CALLOUT_PENDING) && 1125 ((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) { 1126 /* 1127 * Special case where this slipped in while we 1128 * were migrating *as* the callout is about to 1129 * execute. The caller probably holds the lock 1130 * the callout wants. 1131 * 1132 * Get rid of the migration first. Then set 1133 * the flag that tells this code *not* to 1134 * try to remove it from any lists (its not 1135 * on one yet). When the callout wheel runs, 1136 * it will ignore this callout. 1137 */ 1138 c->c_iflags &= ~CALLOUT_PENDING; 1139 c->c_flags &= ~CALLOUT_ACTIVE; 1140 not_on_a_list = 1; 1141 } else { 1142 not_on_a_list = 0; 1143 } 1144 1145 /* 1146 * If the callout was migrating while the callout cpu lock was 1147 * dropped, just drop the sleepqueue lock and check the states 1148 * again. 1149 */ 1150 if (sq_locked != 0 && cc != old_cc) { 1151 #ifdef SMP 1152 CC_UNLOCK(cc); 1153 sleepq_release(&cc_exec_waiting(old_cc, direct)); 1154 sq_locked = 0; 1155 old_cc = NULL; 1156 goto again; 1157 #else 1158 panic("migration should not happen"); 1159 #endif 1160 } 1161 1162 /* 1163 * If the callout is running, try to stop it or drain it. 1164 */ 1165 if (cc_exec_curr(cc, direct) == c) { 1166 /* 1167 * Succeed we to stop it or not, we must clear the 1168 * active flag - this is what API users expect. If we're 1169 * draining and the callout is currently executing, first wait 1170 * until it finishes. 1171 */ 1172 if ((flags & CS_DRAIN) == 0) 1173 c->c_flags &= ~CALLOUT_ACTIVE; 1174 1175 if ((flags & CS_DRAIN) != 0) { 1176 /* 1177 * The current callout is running (or just 1178 * about to run) and blocking is allowed, so 1179 * just wait for the current invocation to 1180 * finish. 1181 */ 1182 if (cc_exec_curr(cc, direct) == c) { 1183 /* 1184 * Use direct calls to sleepqueue interface 1185 * instead of cv/msleep in order to avoid 1186 * a LOR between cc_lock and sleepqueue 1187 * chain spinlocks. This piece of code 1188 * emulates a msleep_spin() call actually. 1189 * 1190 * If we already have the sleepqueue chain 1191 * locked, then we can safely block. If we 1192 * don't already have it locked, however, 1193 * we have to drop the cc_lock to lock 1194 * it. This opens several races, so we 1195 * restart at the beginning once we have 1196 * both locks. If nothing has changed, then 1197 * we will end up back here with sq_locked 1198 * set. 1199 */ 1200 if (!sq_locked) { 1201 CC_UNLOCK(cc); 1202 sleepq_lock( 1203 &cc_exec_waiting(cc, direct)); 1204 sq_locked = 1; 1205 old_cc = cc; 1206 goto again; 1207 } 1208 1209 /* 1210 * Migration could be cancelled here, but 1211 * as long as it is still not sure when it 1212 * will be packed up, just let softclock() 1213 * take care of it. 1214 */ 1215 cc_exec_waiting(cc, direct) = true; 1216 DROP_GIANT(); 1217 CC_UNLOCK(cc); 1218 sleepq_add( 1219 &cc_exec_waiting(cc, direct), 1220 &cc->cc_lock.lock_object, "codrain", 1221 SLEEPQ_SLEEP, 0); 1222 sleepq_wait( 1223 &cc_exec_waiting(cc, direct), 1224 0); 1225 sq_locked = 0; 1226 old_cc = NULL; 1227 1228 /* Reacquire locks previously released. */ 1229 PICKUP_GIANT(); 1230 goto again; 1231 } 1232 c->c_flags &= ~CALLOUT_ACTIVE; 1233 } else if (use_lock && 1234 !cc_exec_cancel(cc, direct) && (drain == NULL)) { 1235 1236 /* 1237 * The current callout is waiting for its 1238 * lock which we hold. Cancel the callout 1239 * and return. After our caller drops the 1240 * lock, the callout will be skipped in 1241 * softclock(). This *only* works with a 1242 * callout_stop() *not* callout_drain() or 1243 * callout_async_drain(). 1244 */ 1245 cc_exec_cancel(cc, direct) = true; 1246 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1247 c, c->c_func, c->c_arg); 1248 KASSERT(!cc_cce_migrating(cc, direct), 1249 ("callout wrongly scheduled for migration")); 1250 if (callout_migrating(c)) { 1251 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1252 #ifdef SMP 1253 cc_migration_cpu(cc, direct) = CPUBLOCK; 1254 cc_migration_time(cc, direct) = 0; 1255 cc_migration_prec(cc, direct) = 0; 1256 cc_migration_func(cc, direct) = NULL; 1257 cc_migration_arg(cc, direct) = NULL; 1258 #endif 1259 } 1260 CC_UNLOCK(cc); 1261 KASSERT(!sq_locked, ("sleepqueue chain locked")); 1262 return (1); 1263 } else if (callout_migrating(c)) { 1264 /* 1265 * The callout is currently being serviced 1266 * and the "next" callout is scheduled at 1267 * its completion with a migration. We remove 1268 * the migration flag so it *won't* get rescheduled, 1269 * but we can't stop the one thats running so 1270 * we return 0. 1271 */ 1272 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1273 #ifdef SMP 1274 /* 1275 * We can't call cc_cce_cleanup here since 1276 * if we do it will remove .ce_curr and 1277 * its still running. This will prevent a 1278 * reschedule of the callout when the 1279 * execution completes. 1280 */ 1281 cc_migration_cpu(cc, direct) = CPUBLOCK; 1282 cc_migration_time(cc, direct) = 0; 1283 cc_migration_prec(cc, direct) = 0; 1284 cc_migration_func(cc, direct) = NULL; 1285 cc_migration_arg(cc, direct) = NULL; 1286 #endif 1287 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 1288 c, c->c_func, c->c_arg); 1289 if (drain) { 1290 KASSERT(cc_exec_drain(cc, direct) == NULL, 1291 ("callout drain function already set to %p", 1292 cc_exec_drain(cc, direct))); 1293 cc_exec_drain(cc, direct) = drain; 1294 } 1295 CC_UNLOCK(cc); 1296 return (0); 1297 } else { 1298 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1299 c, c->c_func, c->c_arg); 1300 if (drain) { 1301 KASSERT(cc_exec_drain(cc, direct) == NULL, 1302 ("callout drain function already set to %p", 1303 cc_exec_drain(cc, direct))); 1304 cc_exec_drain(cc, direct) = drain; 1305 } 1306 } 1307 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 1308 cancelled = 0; 1309 } else 1310 cancelled = 1; 1311 1312 if (sq_locked) 1313 sleepq_release(&cc_exec_waiting(cc, direct)); 1314 1315 if ((c->c_iflags & CALLOUT_PENDING) == 0) { 1316 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1317 c, c->c_func, c->c_arg); 1318 /* 1319 * For not scheduled and not executing callout return 1320 * negative value. 1321 */ 1322 if (cc_exec_curr(cc, direct) != c) 1323 cancelled = -1; 1324 CC_UNLOCK(cc); 1325 return (cancelled); 1326 } 1327 1328 c->c_iflags &= ~CALLOUT_PENDING; 1329 c->c_flags &= ~CALLOUT_ACTIVE; 1330 1331 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1332 c, c->c_func, c->c_arg); 1333 if (not_on_a_list == 0) { 1334 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1335 if (cc_exec_next(cc) == c) 1336 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1337 LIST_REMOVE(c, c_links.le); 1338 } else { 1339 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1340 } 1341 } 1342 CC_UNLOCK(cc); 1343 return (cancelled); 1344 } 1345 1346 void 1347 callout_init(struct callout *c, int mpsafe) 1348 { 1349 bzero(c, sizeof *c); 1350 if (mpsafe) { 1351 c->c_lock = NULL; 1352 c->c_iflags = CALLOUT_RETURNUNLOCKED; 1353 } else { 1354 c->c_lock = &Giant.lock_object; 1355 c->c_iflags = 0; 1356 } 1357 c->c_cpu = cc_default_cpu; 1358 } 1359 1360 void 1361 _callout_init_lock(struct callout *c, struct lock_object *lock, int flags) 1362 { 1363 bzero(c, sizeof *c); 1364 c->c_lock = lock; 1365 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1366 ("callout_init_lock: bad flags %d", flags)); 1367 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1368 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1369 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & LC_SLEEPABLE), 1370 ("%s: callout %p has sleepable lock", __func__, c)); 1371 c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1372 c->c_cpu = cc_default_cpu; 1373 } 1374 1375 static int 1376 flssbt(sbintime_t sbt) 1377 { 1378 1379 sbt += (uint64_t)sbt >> 1; 1380 if (sizeof(long) >= sizeof(sbintime_t)) 1381 return (flsl(sbt)); 1382 if (sbt >= SBT_1S) 1383 return (flsl(((uint64_t)sbt) >> 32) + 32); 1384 return (flsl(sbt)); 1385 } 1386 1387 /* 1388 * Dump immediate statistic snapshot of the scheduled callouts. 1389 */ 1390 static int 1391 sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1392 { 1393 struct callout *tmp; 1394 struct callout_cpu *cc; 1395 struct callout_list *sc; 1396 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; 1397 int ct[64], cpr[64], ccpbk[32]; 1398 int error, val, i, count, tcum, pcum, maxc, c, medc; 1399 int cpu; 1400 1401 val = 0; 1402 error = sysctl_handle_int(oidp, &val, 0, req); 1403 if (error != 0 || req->newptr == NULL) 1404 return (error); 1405 count = maxc = 0; 1406 st = spr = maxt = maxpr = 0; 1407 bzero(ccpbk, sizeof(ccpbk)); 1408 bzero(ct, sizeof(ct)); 1409 bzero(cpr, sizeof(cpr)); 1410 now = sbinuptime(); 1411 CPU_FOREACH(cpu) { 1412 cc = CC_CPU(cpu); 1413 CC_LOCK(cc); 1414 for (i = 0; i < callwheelsize; i++) { 1415 sc = &cc->cc_callwheel[i]; 1416 c = 0; 1417 LIST_FOREACH(tmp, sc, c_links.le) { 1418 c++; 1419 t = tmp->c_time - now; 1420 if (t < 0) 1421 t = 0; 1422 st += t / SBT_1US; 1423 spr += tmp->c_precision / SBT_1US; 1424 if (t > maxt) 1425 maxt = t; 1426 if (tmp->c_precision > maxpr) 1427 maxpr = tmp->c_precision; 1428 ct[flssbt(t)]++; 1429 cpr[flssbt(tmp->c_precision)]++; 1430 } 1431 if (c > maxc) 1432 maxc = c; 1433 ccpbk[fls(c + c / 2)]++; 1434 count += c; 1435 } 1436 CC_UNLOCK(cc); 1437 } 1438 1439 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1440 tcum += ct[i]; 1441 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1442 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) 1443 pcum += cpr[i]; 1444 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1445 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1446 c += ccpbk[i]; 1447 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1448 1449 printf("Scheduled callouts statistic snapshot:\n"); 1450 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1451 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1452 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1453 medc, 1454 count / callwheelsize / mp_ncpus, 1455 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1456 maxc); 1457 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1458 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1459 (st / count) / 1000000, (st / count) % 1000000, 1460 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); 1461 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1462 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, 1463 (spr / count) / 1000000, (spr / count) % 1000000, 1464 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); 1465 printf(" Distribution: \tbuckets\t time\t tcum\t" 1466 " prec\t pcum\n"); 1467 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1468 if (ct[i] == 0 && cpr[i] == 0) 1469 continue; 1470 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1471 tcum += ct[i]; 1472 pcum += cpr[i]; 1473 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", 1474 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1475 i - 1 - (32 - CC_HASH_SHIFT), 1476 ct[i], tcum, cpr[i], pcum); 1477 } 1478 return (error); 1479 } 1480 SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1481 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1482 0, 0, sysctl_kern_callout_stat, "I", 1483 "Dump immediate statistic snapshot of the scheduled callouts"); 1484 1485 #ifdef DDB 1486 static void 1487 _show_callout(struct callout *c) 1488 { 1489 1490 db_printf("callout %p\n", c); 1491 #define C_DB_PRINTF(f, e) db_printf(" %s = " f "\n", #e, c->e); 1492 db_printf(" &c_links = %p\n", &(c->c_links)); 1493 C_DB_PRINTF("%" PRId64, c_time); 1494 C_DB_PRINTF("%" PRId64, c_precision); 1495 C_DB_PRINTF("%p", c_arg); 1496 C_DB_PRINTF("%p", c_func); 1497 C_DB_PRINTF("%p", c_lock); 1498 C_DB_PRINTF("%#x", c_flags); 1499 C_DB_PRINTF("%#x", c_iflags); 1500 C_DB_PRINTF("%d", c_cpu); 1501 #undef C_DB_PRINTF 1502 } 1503 1504 DB_SHOW_COMMAND(callout, db_show_callout) 1505 { 1506 1507 if (!have_addr) { 1508 db_printf("usage: show callout <struct callout *>\n"); 1509 return; 1510 } 1511 1512 _show_callout((struct callout *)addr); 1513 } 1514 1515 static void 1516 _show_last_callout(int cpu, int direct, const char *dirstr) 1517 { 1518 struct callout_cpu *cc; 1519 void *func, *arg; 1520 1521 cc = CC_CPU(cpu); 1522 func = cc_exec_last_func(cc, direct); 1523 arg = cc_exec_last_arg(cc, direct); 1524 db_printf("cpu %d last%s callout function: %p ", cpu, dirstr, func); 1525 db_printsym((db_expr_t)func, DB_STGY_ANY); 1526 db_printf("\ncpu %d last%s callout argument: %p\n", cpu, dirstr, arg); 1527 } 1528 1529 DB_SHOW_COMMAND_FLAGS(callout_last, db_show_callout_last, DB_CMD_MEMSAFE) 1530 { 1531 int cpu, last; 1532 1533 if (have_addr) { 1534 if (addr < 0 || addr > mp_maxid || CPU_ABSENT(addr)) { 1535 db_printf("no such cpu: %d\n", (int)addr); 1536 return; 1537 } 1538 cpu = last = addr; 1539 } else { 1540 cpu = 0; 1541 last = mp_maxid; 1542 } 1543 1544 while (cpu <= last) { 1545 if (!CPU_ABSENT(cpu)) { 1546 _show_last_callout(cpu, 0, ""); 1547 _show_last_callout(cpu, 1, " direct"); 1548 } 1549 cpu++; 1550 } 1551 } 1552 #endif /* DDB */ 1553