1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include "opt_callout_profiling.h" 43 #include "opt_ddb.h" 44 #include "opt_rss.h" 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/bus.h> 49 #include <sys/callout.h> 50 #include <sys/domainset.h> 51 #include <sys/file.h> 52 #include <sys/interrupt.h> 53 #include <sys/kernel.h> 54 #include <sys/ktr.h> 55 #include <sys/kthread.h> 56 #include <sys/lock.h> 57 #include <sys/malloc.h> 58 #include <sys/mutex.h> 59 #include <sys/proc.h> 60 #include <sys/sched.h> 61 #include <sys/sdt.h> 62 #include <sys/sleepqueue.h> 63 #include <sys/sysctl.h> 64 #include <sys/smp.h> 65 #include <sys/unistd.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 DPCPU_DECLARE(sbintime_t, hardclocktime); 78 79 SDT_PROVIDER_DEFINE(callout_execute); 80 SDT_PROBE_DEFINE1(callout_execute, , , callout__start, "struct callout *"); 81 SDT_PROBE_DEFINE1(callout_execute, , , callout__end, "struct callout *"); 82 83 static void softclock_thread(void *arg); 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 struct thread *cc_thread; 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 static 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 static 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_call_cc() 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 ncallout = imin(16 + maxproc + maxfiles, 18508); 289 TUNABLE_INT_FETCH("kern.ncallout", &ncallout); 290 291 /* 292 * Calculate callout wheel size, should be next power of two higher 293 * than 'ncallout'. 294 */ 295 callwheelsize = 1 << fls(ncallout); 296 callwheelmask = callwheelsize - 1; 297 298 /* 299 * Fetch whether we're pinning the swi's or not. 300 */ 301 TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi); 302 TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi); 303 304 /* 305 * Initialize callout wheels. The software interrupt threads 306 * are created later. 307 */ 308 cc_default_cpu = PCPU_GET(cpuid); 309 CPU_FOREACH(cpu) { 310 cc = CC_CPU(cpu); 311 callout_cpu_init(cc, cpu); 312 } 313 } 314 SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); 315 316 /* 317 * Initialize the per-cpu callout structures. 318 */ 319 static void 320 callout_cpu_init(struct callout_cpu *cc, int cpu) 321 { 322 int i; 323 324 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN); 325 cc->cc_inited = 1; 326 cc->cc_callwheel = malloc_domainset(sizeof(struct callout_list) * 327 callwheelsize, M_CALLOUT, 328 DOMAINSET_PREF(pcpu_find(cpu)->pc_domain), M_WAITOK); 329 for (i = 0; i < callwheelsize; i++) 330 LIST_INIT(&cc->cc_callwheel[i]); 331 TAILQ_INIT(&cc->cc_expireq); 332 cc->cc_firstevent = SBT_MAX; 333 for (i = 0; i < 2; i++) 334 cc_cce_cleanup(cc, i); 335 #ifdef KTR 336 snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name), 337 "callwheel cpu %d", cpu); 338 #endif 339 } 340 341 #ifdef SMP 342 /* 343 * Switches the cpu tied to a specific callout. 344 * The function expects a locked incoming callout cpu and returns with 345 * locked outcoming callout cpu. 346 */ 347 static struct callout_cpu * 348 callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu) 349 { 350 struct callout_cpu *new_cc; 351 352 MPASS(c != NULL && cc != NULL); 353 CC_LOCK_ASSERT(cc); 354 355 /* 356 * Avoid interrupts and preemption firing after the callout cpu 357 * is blocked in order to avoid deadlocks as the new thread 358 * may be willing to acquire the callout cpu lock. 359 */ 360 c->c_cpu = CPUBLOCK; 361 spinlock_enter(); 362 CC_UNLOCK(cc); 363 new_cc = CC_CPU(new_cpu); 364 CC_LOCK(new_cc); 365 spinlock_exit(); 366 c->c_cpu = new_cpu; 367 return (new_cc); 368 } 369 #endif 370 371 /* 372 * Start softclock threads. 373 */ 374 static void 375 start_softclock(void *dummy) 376 { 377 struct proc *p; 378 struct thread *td; 379 struct callout_cpu *cc; 380 int cpu, error; 381 bool pin_swi; 382 383 p = NULL; 384 CPU_FOREACH(cpu) { 385 cc = CC_CPU(cpu); 386 error = kproc_kthread_add(softclock_thread, cc, &p, &td, 387 RFSTOPPED, 0, "clock", "clock (%d)", cpu); 388 if (error != 0) 389 panic("failed to create softclock thread for cpu %d: %d", 390 cpu, error); 391 CC_LOCK(cc); 392 cc->cc_thread = td; 393 thread_lock(td); 394 sched_class(td, PRI_ITHD); 395 sched_prio(td, PI_SWI(SWI_CLOCK)); 396 TD_SET_IWAIT(td); 397 thread_lock_set(td, (struct mtx *)&cc->cc_lock); 398 thread_unlock(td); 399 if (cpu == cc_default_cpu) 400 pin_swi = pin_default_swi; 401 else 402 pin_swi = pin_pcpu_swi; 403 if (pin_swi) { 404 error = cpuset_setithread(td->td_tid, cpu); 405 if (error != 0) 406 printf("%s: %s clock couldn't be pinned to cpu %d: %d\n", 407 __func__, cpu == cc_default_cpu ? 408 "default" : "per-cpu", cpu, error); 409 } 410 } 411 } 412 SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); 413 414 #define CC_HASH_SHIFT 8 415 416 static inline u_int 417 callout_hash(sbintime_t sbt) 418 { 419 420 return (sbt >> (32 - CC_HASH_SHIFT)); 421 } 422 423 static inline u_int 424 callout_get_bucket(sbintime_t sbt) 425 { 426 427 return (callout_hash(sbt) & callwheelmask); 428 } 429 430 void 431 callout_process(sbintime_t now) 432 { 433 struct callout *tmp, *tmpn; 434 struct callout_cpu *cc; 435 struct callout_list *sc; 436 struct thread *td; 437 sbintime_t first, last, max, tmp_max; 438 uint32_t lookahead; 439 u_int firstb, lastb, nowb; 440 #ifdef CALLOUT_PROFILING 441 int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0; 442 #endif 443 444 cc = CC_SELF(); 445 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET); 446 447 /* Compute the buckets of the last scan and present times. */ 448 firstb = callout_hash(cc->cc_lastscan); 449 cc->cc_lastscan = now; 450 nowb = callout_hash(now); 451 452 /* Compute the last bucket and minimum time of the bucket after it. */ 453 if (nowb == firstb) 454 lookahead = (SBT_1S / 16); 455 else if (nowb - firstb == 1) 456 lookahead = (SBT_1S / 8); 457 else 458 lookahead = (SBT_1S / 2); 459 first = last = now; 460 first += (lookahead / 2); 461 last += lookahead; 462 last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); 463 lastb = callout_hash(last) - 1; 464 max = last; 465 466 /* 467 * Check if we wrapped around the entire wheel from the last scan. 468 * In case, we need to scan entirely the wheel for pending callouts. 469 */ 470 if (lastb - firstb >= callwheelsize) { 471 lastb = firstb + callwheelsize - 1; 472 if (nowb - firstb >= callwheelsize) 473 nowb = lastb; 474 } 475 476 /* Iterate callwheel from firstb to nowb and then up to lastb. */ 477 do { 478 sc = &cc->cc_callwheel[firstb & callwheelmask]; 479 tmp = LIST_FIRST(sc); 480 while (tmp != NULL) { 481 /* Run the callout if present time within allowed. */ 482 if (tmp->c_time <= now) { 483 /* 484 * Consumer told us the callout may be run 485 * directly from hardware interrupt context. 486 */ 487 if (tmp->c_iflags & CALLOUT_DIRECT) { 488 #ifdef CALLOUT_PROFILING 489 ++depth_dir; 490 #endif 491 cc_exec_next(cc) = 492 LIST_NEXT(tmp, c_links.le); 493 cc->cc_bucket = firstb & callwheelmask; 494 LIST_REMOVE(tmp, c_links.le); 495 softclock_call_cc(tmp, cc, 496 #ifdef CALLOUT_PROFILING 497 &mpcalls_dir, &lockcalls_dir, NULL, 498 #endif 499 1); 500 tmp = cc_exec_next(cc); 501 cc_exec_next(cc) = NULL; 502 } else { 503 tmpn = LIST_NEXT(tmp, c_links.le); 504 LIST_REMOVE(tmp, c_links.le); 505 TAILQ_INSERT_TAIL(&cc->cc_expireq, 506 tmp, c_links.tqe); 507 tmp->c_iflags |= CALLOUT_PROCESSED; 508 tmp = tmpn; 509 } 510 continue; 511 } 512 /* Skip events from distant future. */ 513 if (tmp->c_time >= max) 514 goto next; 515 /* 516 * Event minimal time is bigger than present maximal 517 * time, so it cannot be aggregated. 518 */ 519 if (tmp->c_time > last) { 520 lastb = nowb; 521 goto next; 522 } 523 /* Update first and last time, respecting this event. */ 524 if (tmp->c_time < first) 525 first = tmp->c_time; 526 tmp_max = tmp->c_time + tmp->c_precision; 527 if (tmp_max < last) 528 last = tmp_max; 529 next: 530 tmp = LIST_NEXT(tmp, c_links.le); 531 } 532 /* Proceed with the next bucket. */ 533 firstb++; 534 /* 535 * Stop if we looked after present time and found 536 * some event we can't execute at now. 537 * Stop if we looked far enough into the future. 538 */ 539 } while (((int)(firstb - lastb)) <= 0); 540 cc->cc_firstevent = last; 541 cpu_new_callout(curcpu, last, first); 542 543 #ifdef CALLOUT_PROFILING 544 avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8; 545 avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8; 546 avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8; 547 #endif 548 if (!TAILQ_EMPTY(&cc->cc_expireq)) { 549 td = cc->cc_thread; 550 if (TD_AWAITING_INTR(td)) { 551 thread_lock_block_wait(td); 552 THREAD_LOCK_ASSERT(td, MA_OWNED); 553 TD_CLR_IWAIT(td); 554 sched_add(td, SRQ_INTR); 555 } else 556 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 557 } else 558 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 559 } 560 561 static struct callout_cpu * 562 callout_lock(struct callout *c) 563 { 564 struct callout_cpu *cc; 565 int cpu; 566 567 for (;;) { 568 cpu = c->c_cpu; 569 #ifdef SMP 570 if (cpu == CPUBLOCK) { 571 while (c->c_cpu == CPUBLOCK) 572 cpu_spinwait(); 573 continue; 574 } 575 #endif 576 cc = CC_CPU(cpu); 577 CC_LOCK(cc); 578 if (cpu == c->c_cpu) 579 break; 580 CC_UNLOCK(cc); 581 } 582 return (cc); 583 } 584 585 static void 586 callout_cc_add(struct callout *c, struct callout_cpu *cc, 587 sbintime_t sbt, sbintime_t precision, void (*func)(void *), 588 void *arg, int cpu, int flags) 589 { 590 int bucket; 591 592 CC_LOCK_ASSERT(cc); 593 if (sbt < cc->cc_lastscan) 594 sbt = cc->cc_lastscan; 595 c->c_arg = arg; 596 c->c_iflags |= CALLOUT_PENDING; 597 c->c_iflags &= ~CALLOUT_PROCESSED; 598 c->c_flags |= CALLOUT_ACTIVE; 599 if (flags & C_DIRECT_EXEC) 600 c->c_iflags |= CALLOUT_DIRECT; 601 c->c_func = func; 602 c->c_time = sbt; 603 c->c_precision = precision; 604 bucket = callout_get_bucket(c->c_time); 605 CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x", 606 c, (int)(c->c_precision >> 32), 607 (u_int)(c->c_precision & 0xffffffff)); 608 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); 609 if (cc->cc_bucket == bucket) 610 cc_exec_next(cc) = c; 611 612 /* 613 * Inform the eventtimers(4) subsystem there's a new callout 614 * that has been inserted, but only if really required. 615 */ 616 if (SBT_MAX - c->c_time < c->c_precision) 617 c->c_precision = SBT_MAX - c->c_time; 618 sbt = c->c_time + c->c_precision; 619 if (sbt < cc->cc_firstevent) { 620 cc->cc_firstevent = sbt; 621 cpu_new_callout(cpu, sbt, c->c_time); 622 } 623 } 624 625 static void 626 softclock_call_cc(struct callout *c, struct callout_cpu *cc, 627 #ifdef CALLOUT_PROFILING 628 int *mpcalls, int *lockcalls, int *gcalls, 629 #endif 630 int direct) 631 { 632 struct rm_priotracker tracker; 633 callout_func_t *c_func, *drain; 634 void *c_arg; 635 struct lock_class *class; 636 struct lock_object *c_lock; 637 uintptr_t lock_status; 638 int c_iflags; 639 #ifdef SMP 640 struct callout_cpu *new_cc; 641 callout_func_t *new_func; 642 void *new_arg; 643 int flags, new_cpu; 644 sbintime_t new_prec, new_time; 645 #endif 646 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 647 sbintime_t sbt1, sbt2; 648 struct timespec ts2; 649 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 650 static callout_func_t *lastfunc; 651 #endif 652 653 KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING, 654 ("softclock_call_cc: pend %p %x", c, c->c_iflags)); 655 KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE, 656 ("softclock_call_cc: act %p %x", c, c->c_flags)); 657 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; 658 lock_status = 0; 659 if (c->c_flags & CALLOUT_SHAREDLOCK) { 660 if (class == &lock_class_rm) 661 lock_status = (uintptr_t)&tracker; 662 else 663 lock_status = 1; 664 } 665 c_lock = c->c_lock; 666 c_func = c->c_func; 667 c_arg = c->c_arg; 668 c_iflags = c->c_iflags; 669 c->c_iflags &= ~CALLOUT_PENDING; 670 671 cc_exec_curr(cc, direct) = c; 672 cc_exec_last_func(cc, direct) = c_func; 673 cc_exec_last_arg(cc, direct) = c_arg; 674 cc_exec_cancel(cc, direct) = false; 675 cc_exec_drain(cc, direct) = NULL; 676 CC_UNLOCK(cc); 677 if (c_lock != NULL) { 678 class->lc_lock(c_lock, lock_status); 679 /* 680 * The callout may have been cancelled 681 * while we switched locks. 682 */ 683 if (cc_exec_cancel(cc, direct)) { 684 class->lc_unlock(c_lock); 685 goto skip; 686 } 687 /* The callout cannot be stopped now. */ 688 cc_exec_cancel(cc, direct) = true; 689 if (c_lock == &Giant.lock_object) { 690 #ifdef CALLOUT_PROFILING 691 (*gcalls)++; 692 #endif 693 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", 694 c, c_func, c_arg); 695 } else { 696 #ifdef CALLOUT_PROFILING 697 (*lockcalls)++; 698 #endif 699 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", 700 c, c_func, c_arg); 701 } 702 } else { 703 #ifdef CALLOUT_PROFILING 704 (*mpcalls)++; 705 #endif 706 CTR3(KTR_CALLOUT, "callout %p func %p arg %p", 707 c, c_func, c_arg); 708 } 709 KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running", 710 "func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct); 711 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 712 sbt1 = sbinuptime(); 713 #endif 714 THREAD_NO_SLEEPING(); 715 SDT_PROBE1(callout_execute, , , callout__start, c); 716 c_func(c_arg); 717 SDT_PROBE1(callout_execute, , , callout__end, c); 718 THREAD_SLEEPING_OK(); 719 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 720 sbt2 = sbinuptime(); 721 sbt2 -= sbt1; 722 if (sbt2 > maxdt) { 723 if (lastfunc != c_func || sbt2 > maxdt * 2) { 724 ts2 = sbttots(sbt2); 725 printf( 726 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 727 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); 728 } 729 maxdt = sbt2; 730 lastfunc = c_func; 731 } 732 #endif 733 KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle"); 734 CTR1(KTR_CALLOUT, "callout %p finished", c); 735 if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0) 736 class->lc_unlock(c_lock); 737 skip: 738 CC_LOCK(cc); 739 KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr")); 740 cc_exec_curr(cc, direct) = NULL; 741 if (cc_exec_drain(cc, direct)) { 742 drain = cc_exec_drain(cc, direct); 743 cc_exec_drain(cc, direct) = NULL; 744 CC_UNLOCK(cc); 745 drain(c_arg); 746 CC_LOCK(cc); 747 } 748 if (cc_exec_waiting(cc, direct)) { 749 /* 750 * There is someone waiting for the 751 * callout to complete. 752 * If the callout was scheduled for 753 * migration just cancel it. 754 */ 755 if (cc_cce_migrating(cc, direct)) { 756 cc_cce_cleanup(cc, direct); 757 758 /* 759 * It should be assert here that the callout is not 760 * destroyed but that is not easy. 761 */ 762 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 763 } 764 cc_exec_waiting(cc, direct) = false; 765 CC_UNLOCK(cc); 766 wakeup(&cc_exec_waiting(cc, direct)); 767 CC_LOCK(cc); 768 } else if (cc_cce_migrating(cc, direct)) { 769 #ifdef SMP 770 /* 771 * If the callout was scheduled for 772 * migration just perform it now. 773 */ 774 new_cpu = cc_migration_cpu(cc, direct); 775 new_time = cc_migration_time(cc, direct); 776 new_prec = cc_migration_prec(cc, direct); 777 new_func = cc_migration_func(cc, direct); 778 new_arg = cc_migration_arg(cc, direct); 779 cc_cce_cleanup(cc, direct); 780 781 /* 782 * It should be assert here that the callout is not destroyed 783 * but that is not easy. 784 * 785 * As first thing, handle deferred callout stops. 786 */ 787 if (!callout_migrating(c)) { 788 CTR3(KTR_CALLOUT, 789 "deferred cancelled %p func %p arg %p", 790 c, new_func, new_arg); 791 return; 792 } 793 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 794 795 new_cc = callout_cpu_switch(c, cc, new_cpu); 796 flags = (direct) ? C_DIRECT_EXEC : 0; 797 callout_cc_add(c, new_cc, new_time, new_prec, new_func, 798 new_arg, new_cpu, flags); 799 CC_UNLOCK(new_cc); 800 CC_LOCK(cc); 801 #else 802 panic("migration should not happen"); 803 #endif 804 } 805 } 806 807 /* 808 * The callout mechanism is based on the work of Adam M. Costello and 809 * George Varghese, published in a technical report entitled "Redesigning 810 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 811 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 812 * used in this implementation was published by G. Varghese and T. Lauck in 813 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 814 * the Efficient Implementation of a Timer Facility" in the Proceedings of 815 * the 11th ACM Annual Symposium on Operating Systems Principles, 816 * Austin, Texas Nov 1987. 817 */ 818 819 /* 820 * Software (low priority) clock interrupt thread handler. 821 * Run periodic events from timeout queue. 822 */ 823 static void 824 softclock_thread(void *arg) 825 { 826 struct thread *td = curthread; 827 struct callout_cpu *cc; 828 struct callout *c; 829 #ifdef CALLOUT_PROFILING 830 int depth, gcalls, lockcalls, mpcalls; 831 #endif 832 833 cc = (struct callout_cpu *)arg; 834 CC_LOCK(cc); 835 for (;;) { 836 while (TAILQ_EMPTY(&cc->cc_expireq)) { 837 /* 838 * Use CC_LOCK(cc) as the thread_lock while 839 * idle. 840 */ 841 thread_lock(td); 842 thread_lock_set(td, (struct mtx *)&cc->cc_lock); 843 TD_SET_IWAIT(td); 844 mi_switch(SW_VOL | SWT_IWAIT); 845 846 /* mi_switch() drops thread_lock(). */ 847 CC_LOCK(cc); 848 } 849 850 #ifdef CALLOUT_PROFILING 851 depth = gcalls = lockcalls = mpcalls = 0; 852 #endif 853 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { 854 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 855 softclock_call_cc(c, cc, 856 #ifdef CALLOUT_PROFILING 857 &mpcalls, &lockcalls, &gcalls, 858 #endif 859 0); 860 #ifdef CALLOUT_PROFILING 861 ++depth; 862 #endif 863 } 864 #ifdef CALLOUT_PROFILING 865 avg_depth += (depth * 1000 - avg_depth) >> 8; 866 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 867 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 868 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 869 #endif 870 } 871 } 872 873 void 874 callout_when(sbintime_t sbt, sbintime_t precision, int flags, 875 sbintime_t *res, sbintime_t *prec_res) 876 { 877 sbintime_t to_sbt, to_pr; 878 879 if ((flags & (C_ABSOLUTE | C_PRECALC)) != 0) { 880 *res = sbt; 881 *prec_res = precision; 882 return; 883 } 884 if ((flags & C_HARDCLOCK) != 0 && sbt < tick_sbt) 885 sbt = tick_sbt; 886 if ((flags & C_HARDCLOCK) != 0 || sbt >= sbt_tickthreshold) { 887 /* 888 * Obtain the time of the last hardclock() call on 889 * this CPU directly from the kern_clocksource.c. 890 * This value is per-CPU, but it is equal for all 891 * active ones. 892 */ 893 #ifdef __LP64__ 894 to_sbt = DPCPU_GET(hardclocktime); 895 #else 896 spinlock_enter(); 897 to_sbt = DPCPU_GET(hardclocktime); 898 spinlock_exit(); 899 #endif 900 if (cold && to_sbt == 0) 901 to_sbt = sbinuptime(); 902 if ((flags & C_HARDCLOCK) == 0) 903 to_sbt += tick_sbt; 904 } else 905 to_sbt = sbinuptime(); 906 if (SBT_MAX - to_sbt < sbt) 907 to_sbt = SBT_MAX; 908 else 909 to_sbt += sbt; 910 *res = to_sbt; 911 to_pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : 912 sbt >> C_PRELGET(flags)); 913 *prec_res = to_pr > precision ? to_pr : precision; 914 } 915 916 /* 917 * New interface; clients allocate their own callout structures. 918 * 919 * callout_reset() - establish or change a timeout 920 * callout_stop() - disestablish a timeout 921 * callout_init() - initialize a callout structure so that it can 922 * safely be passed to callout_reset() and callout_stop() 923 * 924 * <sys/callout.h> defines three convenience macros: 925 * 926 * callout_active() - returns truth if callout has not been stopped, 927 * drained, or deactivated since the last time the callout was 928 * reset. 929 * callout_pending() - returns truth if callout is still waiting for timeout 930 * callout_deactivate() - marks the callout as having been serviced 931 */ 932 int 933 callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t prec, 934 callout_func_t *ftn, void *arg, int cpu, int flags) 935 { 936 sbintime_t to_sbt, precision; 937 struct callout_cpu *cc; 938 int cancelled, direct; 939 int ignore_cpu=0; 940 941 cancelled = 0; 942 if (cpu == -1) { 943 ignore_cpu = 1; 944 } else if ((cpu >= MAXCPU) || 945 ((CC_CPU(cpu))->cc_inited == 0)) { 946 /* Invalid CPU spec */ 947 panic("Invalid CPU in callout %d", cpu); 948 } 949 callout_when(sbt, prec, flags, &to_sbt, &precision); 950 951 /* 952 * This flag used to be added by callout_cc_add, but the 953 * first time you call this we could end up with the 954 * wrong direct flag if we don't do it before we add. 955 */ 956 if (flags & C_DIRECT_EXEC) { 957 direct = 1; 958 } else { 959 direct = 0; 960 } 961 KASSERT(!direct || c->c_lock == NULL || 962 (LOCK_CLASS(c->c_lock)->lc_flags & LC_SPINLOCK), 963 ("%s: direct callout %p has non-spin lock", __func__, c)); 964 cc = callout_lock(c); 965 /* 966 * Don't allow migration if the user does not care. 967 */ 968 if (ignore_cpu) { 969 cpu = c->c_cpu; 970 } 971 972 if (cc_exec_curr(cc, direct) == c) { 973 /* 974 * We're being asked to reschedule a callout which is 975 * currently in progress. If there is a lock then we 976 * can cancel the callout if it has not really started. 977 */ 978 if (c->c_lock != NULL && !cc_exec_cancel(cc, direct)) 979 cancelled = cc_exec_cancel(cc, direct) = true; 980 if (cc_exec_waiting(cc, direct) || cc_exec_drain(cc, direct)) { 981 /* 982 * Someone has called callout_drain to kill this 983 * callout. Don't reschedule. 984 */ 985 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 986 cancelled ? "cancelled" : "failed to cancel", 987 c, c->c_func, c->c_arg); 988 CC_UNLOCK(cc); 989 return (cancelled); 990 } 991 #ifdef SMP 992 if (callout_migrating(c)) { 993 /* 994 * This only occurs when a second callout_reset_sbt_on 995 * is made after a previous one moved it into 996 * deferred migration (below). Note we do *not* change 997 * the prev_cpu even though the previous target may 998 * be different. 999 */ 1000 cc_migration_cpu(cc, direct) = cpu; 1001 cc_migration_time(cc, direct) = to_sbt; 1002 cc_migration_prec(cc, direct) = precision; 1003 cc_migration_func(cc, direct) = ftn; 1004 cc_migration_arg(cc, direct) = arg; 1005 cancelled = 1; 1006 CC_UNLOCK(cc); 1007 return (cancelled); 1008 } 1009 #endif 1010 } 1011 if (c->c_iflags & CALLOUT_PENDING) { 1012 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1013 if (cc_exec_next(cc) == c) 1014 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1015 LIST_REMOVE(c, c_links.le); 1016 } else { 1017 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1018 } 1019 cancelled = 1; 1020 c->c_iflags &= ~ CALLOUT_PENDING; 1021 c->c_flags &= ~ CALLOUT_ACTIVE; 1022 } 1023 1024 #ifdef SMP 1025 /* 1026 * If the callout must migrate try to perform it immediately. 1027 * If the callout is currently running, just defer the migration 1028 * to a more appropriate moment. 1029 */ 1030 if (c->c_cpu != cpu) { 1031 if (cc_exec_curr(cc, direct) == c) { 1032 /* 1033 * Pending will have been removed since we are 1034 * actually executing the callout on another 1035 * CPU. That callout should be waiting on the 1036 * lock the caller holds. If we set both 1037 * active/and/pending after we return and the 1038 * lock on the executing callout proceeds, it 1039 * will then see pending is true and return. 1040 * At the return from the actual callout execution 1041 * the migration will occur in softclock_call_cc 1042 * and this new callout will be placed on the 1043 * new CPU via a call to callout_cpu_switch() which 1044 * will get the lock on the right CPU followed 1045 * by a call callout_cc_add() which will add it there. 1046 * (see above in softclock_call_cc()). 1047 */ 1048 cc_migration_cpu(cc, direct) = cpu; 1049 cc_migration_time(cc, direct) = to_sbt; 1050 cc_migration_prec(cc, direct) = precision; 1051 cc_migration_func(cc, direct) = ftn; 1052 cc_migration_arg(cc, direct) = arg; 1053 c->c_iflags |= (CALLOUT_DFRMIGRATION | CALLOUT_PENDING); 1054 c->c_flags |= CALLOUT_ACTIVE; 1055 CTR6(KTR_CALLOUT, 1056 "migration of %p func %p arg %p in %d.%08x to %u deferred", 1057 c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1058 (u_int)(to_sbt & 0xffffffff), cpu); 1059 CC_UNLOCK(cc); 1060 return (cancelled); 1061 } 1062 cc = callout_cpu_switch(c, cc, cpu); 1063 } 1064 #endif 1065 1066 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags); 1067 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", 1068 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1069 (u_int)(to_sbt & 0xffffffff)); 1070 CC_UNLOCK(cc); 1071 1072 return (cancelled); 1073 } 1074 1075 /* 1076 * Common idioms that can be optimized in the future. 1077 */ 1078 int 1079 callout_schedule_on(struct callout *c, int to_ticks, int cpu) 1080 { 1081 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 1082 } 1083 1084 int 1085 callout_schedule(struct callout *c, int to_ticks) 1086 { 1087 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 1088 } 1089 1090 int 1091 _callout_stop_safe(struct callout *c, int flags, callout_func_t *drain) 1092 { 1093 struct callout_cpu *cc, *old_cc; 1094 struct lock_class *class; 1095 int direct, sq_locked, use_lock; 1096 int cancelled, not_on_a_list; 1097 1098 if ((flags & CS_DRAIN) != 0) 1099 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock, 1100 "calling %s", __func__); 1101 1102 KASSERT((flags & CS_DRAIN) == 0 || drain == NULL, 1103 ("Cannot set drain callback and CS_DRAIN flag at the same time")); 1104 1105 /* 1106 * Some old subsystems don't hold Giant while running a callout_stop(), 1107 * so just discard this check for the moment. 1108 */ 1109 if ((flags & CS_DRAIN) == 0 && c->c_lock != NULL) { 1110 if (c->c_lock == &Giant.lock_object) 1111 use_lock = mtx_owned(&Giant); 1112 else { 1113 use_lock = 1; 1114 class = LOCK_CLASS(c->c_lock); 1115 class->lc_assert(c->c_lock, LA_XLOCKED); 1116 } 1117 } else 1118 use_lock = 0; 1119 if (c->c_iflags & CALLOUT_DIRECT) { 1120 direct = 1; 1121 } else { 1122 direct = 0; 1123 } 1124 sq_locked = 0; 1125 old_cc = NULL; 1126 again: 1127 cc = callout_lock(c); 1128 1129 if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) == 1130 (CALLOUT_DFRMIGRATION | CALLOUT_PENDING) && 1131 ((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) { 1132 /* 1133 * Special case where this slipped in while we 1134 * were migrating *as* the callout is about to 1135 * execute. The caller probably holds the lock 1136 * the callout wants. 1137 * 1138 * Get rid of the migration first. Then set 1139 * the flag that tells this code *not* to 1140 * try to remove it from any lists (its not 1141 * on one yet). When the callout wheel runs, 1142 * it will ignore this callout. 1143 */ 1144 c->c_iflags &= ~CALLOUT_PENDING; 1145 c->c_flags &= ~CALLOUT_ACTIVE; 1146 not_on_a_list = 1; 1147 } else { 1148 not_on_a_list = 0; 1149 } 1150 1151 /* 1152 * If the callout was migrating while the callout cpu lock was 1153 * dropped, just drop the sleepqueue lock and check the states 1154 * again. 1155 */ 1156 if (sq_locked != 0 && cc != old_cc) { 1157 #ifdef SMP 1158 CC_UNLOCK(cc); 1159 sleepq_release(&cc_exec_waiting(old_cc, direct)); 1160 sq_locked = 0; 1161 old_cc = NULL; 1162 goto again; 1163 #else 1164 panic("migration should not happen"); 1165 #endif 1166 } 1167 1168 /* 1169 * If the callout is running, try to stop it or drain it. 1170 */ 1171 if (cc_exec_curr(cc, direct) == c) { 1172 /* 1173 * Succeed we to stop it or not, we must clear the 1174 * active flag - this is what API users expect. If we're 1175 * draining and the callout is currently executing, first wait 1176 * until it finishes. 1177 */ 1178 if ((flags & CS_DRAIN) == 0) 1179 c->c_flags &= ~CALLOUT_ACTIVE; 1180 1181 if ((flags & CS_DRAIN) != 0) { 1182 /* 1183 * The current callout is running (or just 1184 * about to run) and blocking is allowed, so 1185 * just wait for the current invocation to 1186 * finish. 1187 */ 1188 if (cc_exec_curr(cc, direct) == c) { 1189 /* 1190 * Use direct calls to sleepqueue interface 1191 * instead of cv/msleep in order to avoid 1192 * a LOR between cc_lock and sleepqueue 1193 * chain spinlocks. This piece of code 1194 * emulates a msleep_spin() call actually. 1195 * 1196 * If we already have the sleepqueue chain 1197 * locked, then we can safely block. If we 1198 * don't already have it locked, however, 1199 * we have to drop the cc_lock to lock 1200 * it. This opens several races, so we 1201 * restart at the beginning once we have 1202 * both locks. If nothing has changed, then 1203 * we will end up back here with sq_locked 1204 * set. 1205 */ 1206 if (!sq_locked) { 1207 CC_UNLOCK(cc); 1208 sleepq_lock( 1209 &cc_exec_waiting(cc, direct)); 1210 sq_locked = 1; 1211 old_cc = cc; 1212 goto again; 1213 } 1214 1215 /* 1216 * Migration could be cancelled here, but 1217 * as long as it is still not sure when it 1218 * will be packed up, just let softclock() 1219 * take care of it. 1220 */ 1221 cc_exec_waiting(cc, direct) = true; 1222 DROP_GIANT(); 1223 CC_UNLOCK(cc); 1224 sleepq_add( 1225 &cc_exec_waiting(cc, direct), 1226 &cc->cc_lock.lock_object, "codrain", 1227 SLEEPQ_SLEEP, 0); 1228 sleepq_wait( 1229 &cc_exec_waiting(cc, direct), 1230 0); 1231 sq_locked = 0; 1232 old_cc = NULL; 1233 1234 /* Reacquire locks previously released. */ 1235 PICKUP_GIANT(); 1236 goto again; 1237 } 1238 c->c_flags &= ~CALLOUT_ACTIVE; 1239 } else if (use_lock && 1240 !cc_exec_cancel(cc, direct) && (drain == NULL)) { 1241 1242 /* 1243 * The current callout is waiting for its 1244 * lock which we hold. Cancel the callout 1245 * and return. After our caller drops the 1246 * lock, the callout will be skipped in 1247 * softclock(). This *only* works with a 1248 * callout_stop() *not* callout_drain() or 1249 * callout_async_drain(). 1250 */ 1251 cc_exec_cancel(cc, direct) = true; 1252 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1253 c, c->c_func, c->c_arg); 1254 KASSERT(!cc_cce_migrating(cc, direct), 1255 ("callout wrongly scheduled for migration")); 1256 if (callout_migrating(c)) { 1257 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1258 #ifdef SMP 1259 cc_migration_cpu(cc, direct) = CPUBLOCK; 1260 cc_migration_time(cc, direct) = 0; 1261 cc_migration_prec(cc, direct) = 0; 1262 cc_migration_func(cc, direct) = NULL; 1263 cc_migration_arg(cc, direct) = NULL; 1264 #endif 1265 } 1266 CC_UNLOCK(cc); 1267 KASSERT(!sq_locked, ("sleepqueue chain locked")); 1268 return (1); 1269 } else if (callout_migrating(c)) { 1270 /* 1271 * The callout is currently being serviced 1272 * and the "next" callout is scheduled at 1273 * its completion with a migration. We remove 1274 * the migration flag so it *won't* get rescheduled, 1275 * but we can't stop the one thats running so 1276 * we return 0. 1277 */ 1278 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1279 #ifdef SMP 1280 /* 1281 * We can't call cc_cce_cleanup here since 1282 * if we do it will remove .ce_curr and 1283 * its still running. This will prevent a 1284 * reschedule of the callout when the 1285 * execution completes. 1286 */ 1287 cc_migration_cpu(cc, direct) = CPUBLOCK; 1288 cc_migration_time(cc, direct) = 0; 1289 cc_migration_prec(cc, direct) = 0; 1290 cc_migration_func(cc, direct) = NULL; 1291 cc_migration_arg(cc, direct) = NULL; 1292 #endif 1293 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 1294 c, c->c_func, c->c_arg); 1295 if (drain) { 1296 KASSERT(cc_exec_drain(cc, direct) == NULL, 1297 ("callout drain function already set to %p", 1298 cc_exec_drain(cc, direct))); 1299 cc_exec_drain(cc, direct) = drain; 1300 } 1301 CC_UNLOCK(cc); 1302 return ((flags & CS_EXECUTING) != 0); 1303 } else { 1304 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1305 c, c->c_func, c->c_arg); 1306 if (drain) { 1307 KASSERT(cc_exec_drain(cc, direct) == NULL, 1308 ("callout drain function already set to %p", 1309 cc_exec_drain(cc, direct))); 1310 cc_exec_drain(cc, direct) = drain; 1311 } 1312 } 1313 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 1314 cancelled = ((flags & CS_EXECUTING) != 0); 1315 } else 1316 cancelled = 1; 1317 1318 if (sq_locked) 1319 sleepq_release(&cc_exec_waiting(cc, direct)); 1320 1321 if ((c->c_iflags & CALLOUT_PENDING) == 0) { 1322 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1323 c, c->c_func, c->c_arg); 1324 /* 1325 * For not scheduled and not executing callout return 1326 * negative value. 1327 */ 1328 if (cc_exec_curr(cc, direct) != c) 1329 cancelled = -1; 1330 CC_UNLOCK(cc); 1331 return (cancelled); 1332 } 1333 1334 c->c_iflags &= ~CALLOUT_PENDING; 1335 c->c_flags &= ~CALLOUT_ACTIVE; 1336 1337 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1338 c, c->c_func, c->c_arg); 1339 if (not_on_a_list == 0) { 1340 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1341 if (cc_exec_next(cc) == c) 1342 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1343 LIST_REMOVE(c, c_links.le); 1344 } else { 1345 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1346 } 1347 } 1348 CC_UNLOCK(cc); 1349 return (cancelled); 1350 } 1351 1352 void 1353 callout_init(struct callout *c, int mpsafe) 1354 { 1355 bzero(c, sizeof *c); 1356 if (mpsafe) { 1357 c->c_lock = NULL; 1358 c->c_iflags = CALLOUT_RETURNUNLOCKED; 1359 } else { 1360 c->c_lock = &Giant.lock_object; 1361 c->c_iflags = 0; 1362 } 1363 c->c_cpu = cc_default_cpu; 1364 } 1365 1366 void 1367 _callout_init_lock(struct callout *c, struct lock_object *lock, int flags) 1368 { 1369 bzero(c, sizeof *c); 1370 c->c_lock = lock; 1371 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1372 ("callout_init_lock: bad flags %d", flags)); 1373 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1374 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1375 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & LC_SLEEPABLE), 1376 ("%s: callout %p has sleepable lock", __func__, c)); 1377 c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1378 c->c_cpu = cc_default_cpu; 1379 } 1380 1381 static int 1382 flssbt(sbintime_t sbt) 1383 { 1384 1385 sbt += (uint64_t)sbt >> 1; 1386 if (sizeof(long) >= sizeof(sbintime_t)) 1387 return (flsl(sbt)); 1388 if (sbt >= SBT_1S) 1389 return (flsl(((uint64_t)sbt) >> 32) + 32); 1390 return (flsl(sbt)); 1391 } 1392 1393 /* 1394 * Dump immediate statistic snapshot of the scheduled callouts. 1395 */ 1396 static int 1397 sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1398 { 1399 struct callout *tmp; 1400 struct callout_cpu *cc; 1401 struct callout_list *sc; 1402 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; 1403 int ct[64], cpr[64], ccpbk[32]; 1404 int error, val, i, count, tcum, pcum, maxc, c, medc; 1405 int cpu; 1406 1407 val = 0; 1408 error = sysctl_handle_int(oidp, &val, 0, req); 1409 if (error != 0 || req->newptr == NULL) 1410 return (error); 1411 count = maxc = 0; 1412 st = spr = maxt = maxpr = 0; 1413 bzero(ccpbk, sizeof(ccpbk)); 1414 bzero(ct, sizeof(ct)); 1415 bzero(cpr, sizeof(cpr)); 1416 now = sbinuptime(); 1417 CPU_FOREACH(cpu) { 1418 cc = CC_CPU(cpu); 1419 CC_LOCK(cc); 1420 for (i = 0; i < callwheelsize; i++) { 1421 sc = &cc->cc_callwheel[i]; 1422 c = 0; 1423 LIST_FOREACH(tmp, sc, c_links.le) { 1424 c++; 1425 t = tmp->c_time - now; 1426 if (t < 0) 1427 t = 0; 1428 st += t / SBT_1US; 1429 spr += tmp->c_precision / SBT_1US; 1430 if (t > maxt) 1431 maxt = t; 1432 if (tmp->c_precision > maxpr) 1433 maxpr = tmp->c_precision; 1434 ct[flssbt(t)]++; 1435 cpr[flssbt(tmp->c_precision)]++; 1436 } 1437 if (c > maxc) 1438 maxc = c; 1439 ccpbk[fls(c + c / 2)]++; 1440 count += c; 1441 } 1442 CC_UNLOCK(cc); 1443 } 1444 1445 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1446 tcum += ct[i]; 1447 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1448 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) 1449 pcum += cpr[i]; 1450 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1451 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1452 c += ccpbk[i]; 1453 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1454 1455 printf("Scheduled callouts statistic snapshot:\n"); 1456 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1457 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1458 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1459 medc, 1460 count / callwheelsize / mp_ncpus, 1461 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1462 maxc); 1463 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1464 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1465 (st / count) / 1000000, (st / count) % 1000000, 1466 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); 1467 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1468 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, 1469 (spr / count) / 1000000, (spr / count) % 1000000, 1470 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); 1471 printf(" Distribution: \tbuckets\t time\t tcum\t" 1472 " prec\t pcum\n"); 1473 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1474 if (ct[i] == 0 && cpr[i] == 0) 1475 continue; 1476 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1477 tcum += ct[i]; 1478 pcum += cpr[i]; 1479 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", 1480 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1481 i - 1 - (32 - CC_HASH_SHIFT), 1482 ct[i], tcum, cpr[i], pcum); 1483 } 1484 return (error); 1485 } 1486 SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1487 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1488 0, 0, sysctl_kern_callout_stat, "I", 1489 "Dump immediate statistic snapshot of the scheduled callouts"); 1490 1491 #ifdef DDB 1492 static void 1493 _show_callout(struct callout *c) 1494 { 1495 1496 db_printf("callout %p\n", c); 1497 #define C_DB_PRINTF(f, e) db_printf(" %s = " f "\n", #e, c->e); 1498 db_printf(" &c_links = %p\n", &(c->c_links)); 1499 C_DB_PRINTF("%" PRId64, c_time); 1500 C_DB_PRINTF("%" PRId64, c_precision); 1501 C_DB_PRINTF("%p", c_arg); 1502 C_DB_PRINTF("%p", c_func); 1503 C_DB_PRINTF("%p", c_lock); 1504 C_DB_PRINTF("%#x", c_flags); 1505 C_DB_PRINTF("%#x", c_iflags); 1506 C_DB_PRINTF("%d", c_cpu); 1507 #undef C_DB_PRINTF 1508 } 1509 1510 DB_SHOW_COMMAND(callout, db_show_callout) 1511 { 1512 1513 if (!have_addr) { 1514 db_printf("usage: show callout <struct callout *>\n"); 1515 return; 1516 } 1517 1518 _show_callout((struct callout *)addr); 1519 } 1520 1521 static void 1522 _show_last_callout(int cpu, int direct, const char *dirstr) 1523 { 1524 struct callout_cpu *cc; 1525 void *func, *arg; 1526 1527 cc = CC_CPU(cpu); 1528 func = cc_exec_last_func(cc, direct); 1529 arg = cc_exec_last_arg(cc, direct); 1530 db_printf("cpu %d last%s callout function: %p ", cpu, dirstr, func); 1531 db_printsym((db_expr_t)func, DB_STGY_ANY); 1532 db_printf("\ncpu %d last%s callout argument: %p\n", cpu, dirstr, arg); 1533 } 1534 1535 DB_SHOW_COMMAND(callout_last, db_show_callout_last) 1536 { 1537 int cpu, last; 1538 1539 if (have_addr) { 1540 if (addr < 0 || addr > mp_maxid || CPU_ABSENT(addr)) { 1541 db_printf("no such cpu: %d\n", (int)addr); 1542 return; 1543 } 1544 cpu = last = addr; 1545 } else { 1546 cpu = 0; 1547 last = mp_maxid; 1548 } 1549 1550 while (cpu <= last) { 1551 if (!CPU_ABSENT(cpu)) { 1552 _show_last_callout(cpu, 0, ""); 1553 _show_last_callout(cpu, 1, " direct"); 1554 } 1555 cpu++; 1556 } 1557 } 1558 #endif /* DDB */ 1559