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