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 37 #include <sys/cdefs.h> 38 #include "opt_callout_profiling.h" 39 #include "opt_ddb.h" 40 #include "opt_rss.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/bus.h> 45 #include <sys/callout.h> 46 #include <sys/domainset.h> 47 #include <sys/file.h> 48 #include <sys/interrupt.h> 49 #include <sys/kernel.h> 50 #include <sys/ktr.h> 51 #include <sys/kthread.h> 52 #include <sys/lock.h> 53 #include <sys/malloc.h> 54 #include <sys/mutex.h> 55 #include <sys/proc.h> 56 #include <sys/random.h> 57 #include <sys/sched.h> 58 #include <sys/sdt.h> 59 #include <sys/sleepqueue.h> 60 #include <sys/sysctl.h> 61 #include <sys/smp.h> 62 #include <sys/unistd.h> 63 64 #ifdef DDB 65 #include <ddb/ddb.h> 66 #include <ddb/db_sym.h> 67 #include <machine/_inttypes.h> 68 #endif 69 70 #ifdef SMP 71 #include <machine/cpu.h> 72 #endif 73 74 DPCPU_DECLARE(sbintime_t, hardclocktime); 75 76 SDT_PROVIDER_DEFINE(callout_execute); 77 SDT_PROBE_DEFINE1(callout_execute, , , callout__start, "struct callout *"); 78 SDT_PROBE_DEFINE1(callout_execute, , , callout__end, "struct callout *"); 79 80 static void softclock_thread(void *arg); 81 82 #ifdef CALLOUT_PROFILING 83 static int avg_depth; 84 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, 85 "Average number of items examined per softclock call. Units = 1/1000"); 86 static int avg_gcalls; 87 SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, 88 "Average number of Giant callouts made per softclock call. Units = 1/1000"); 89 static int avg_lockcalls; 90 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0, 91 "Average number of lock callouts made per softclock call. Units = 1/1000"); 92 static int avg_mpcalls; 93 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, 94 "Average number of MP callouts made per softclock call. Units = 1/1000"); 95 static int avg_depth_dir; 96 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0, 97 "Average number of direct callouts examined per callout_process call. " 98 "Units = 1/1000"); 99 static int avg_lockcalls_dir; 100 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD, 101 &avg_lockcalls_dir, 0, "Average number of lock direct callouts made per " 102 "callout_process call. Units = 1/1000"); 103 static int avg_mpcalls_dir; 104 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir, 105 0, "Average number of MP direct callouts made per callout_process call. " 106 "Units = 1/1000"); 107 #endif 108 109 static int ncallout; 110 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &ncallout, 0, 111 "Number of entries in callwheel and size of timeout() preallocation"); 112 113 #ifdef RSS 114 static int pin_default_swi = 1; 115 static int pin_pcpu_swi = 1; 116 #else 117 static int pin_default_swi = 0; 118 static int pin_pcpu_swi = 0; 119 #endif 120 121 SYSCTL_INT(_kern, OID_AUTO, pin_default_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_default_swi, 122 0, "Pin the default (non-per-cpu) swi (shared with PCPU 0 swi)"); 123 SYSCTL_INT(_kern, OID_AUTO, pin_pcpu_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_pcpu_swi, 124 0, "Pin the per-CPU swis (except PCPU 0, which is also default)"); 125 126 /* 127 * TODO: 128 * allocate more timeout table slots when table overflows. 129 */ 130 static u_int __read_mostly callwheelsize; 131 static u_int __read_mostly callwheelmask; 132 133 /* 134 * The callout cpu exec entities represent informations necessary for 135 * describing the state of callouts currently running on the CPU and the ones 136 * necessary for migrating callouts to the new callout cpu. In particular, 137 * the first entry of the array cc_exec_entity holds informations for callout 138 * running in SWI thread context, while the second one holds informations 139 * for callout running directly from hardware interrupt context. 140 * The cached informations are very important for deferring migration when 141 * the migrating callout is already running. 142 */ 143 struct cc_exec { 144 struct callout *cc_curr; 145 callout_func_t *cc_drain; 146 void *cc_last_func; 147 void *cc_last_arg; 148 #ifdef SMP 149 callout_func_t *ce_migration_func; 150 void *ce_migration_arg; 151 sbintime_t ce_migration_time; 152 sbintime_t ce_migration_prec; 153 int ce_migration_cpu; 154 #endif 155 bool cc_cancel; 156 bool cc_waiting; 157 }; 158 159 /* 160 * There is one struct callout_cpu per cpu, holding all relevant 161 * state for the callout processing thread on the individual CPU. 162 */ 163 struct callout_cpu { 164 struct mtx_padalign cc_lock; 165 struct cc_exec cc_exec_entity[2]; 166 struct callout *cc_next; 167 struct callout_list *cc_callwheel; 168 struct callout_tailq cc_expireq; 169 sbintime_t cc_firstevent; 170 sbintime_t cc_lastscan; 171 struct thread *cc_thread; 172 u_int cc_bucket; 173 #ifdef KTR 174 char cc_ktr_event_name[20]; 175 #endif 176 }; 177 178 #define callout_migrating(c) ((c)->c_iflags & CALLOUT_DFRMIGRATION) 179 180 #define cc_exec_curr(cc, dir) cc->cc_exec_entity[dir].cc_curr 181 #define cc_exec_last_func(cc, dir) cc->cc_exec_entity[dir].cc_last_func 182 #define cc_exec_last_arg(cc, dir) cc->cc_exec_entity[dir].cc_last_arg 183 #define cc_exec_drain(cc, dir) cc->cc_exec_entity[dir].cc_drain 184 #define cc_exec_next(cc) cc->cc_next 185 #define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel 186 #define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting 187 #ifdef SMP 188 #define cc_migration_func(cc, dir) cc->cc_exec_entity[dir].ce_migration_func 189 #define cc_migration_arg(cc, dir) cc->cc_exec_entity[dir].ce_migration_arg 190 #define cc_migration_cpu(cc, dir) cc->cc_exec_entity[dir].ce_migration_cpu 191 #define cc_migration_time(cc, dir) cc->cc_exec_entity[dir].ce_migration_time 192 #define cc_migration_prec(cc, dir) cc->cc_exec_entity[dir].ce_migration_prec 193 194 DPCPU_DEFINE_STATIC(struct callout_cpu, cc_cpu); 195 #define CPUBLOCK MAXCPU 196 #define CC_CPU(cpu) DPCPU_ID_PTR(cpu, cc_cpu) 197 #define CC_SELF() CC_CPU(PCPU_GET(cpuid)) 198 #else 199 static struct callout_cpu cc_cpu; 200 #define CC_CPU(cpu) (&cc_cpu) 201 #define CC_SELF() (&cc_cpu) 202 #endif 203 #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) 204 #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) 205 #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) 206 207 static int __read_mostly cc_default_cpu; 208 209 static void callout_cpu_init(struct callout_cpu *cc, int cpu); 210 static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, 211 #ifdef CALLOUT_PROFILING 212 int *mpcalls, int *lockcalls, int *gcalls, 213 #endif 214 int direct); 215 216 static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); 217 218 /** 219 * Locked by cc_lock: 220 * cc_curr - If a callout is in progress, it is cc_curr. 221 * If cc_curr is non-NULL, threads waiting in 222 * callout_drain() will be woken up as soon as the 223 * relevant callout completes. 224 * cc_cancel - Changing to 1 with both callout_lock and cc_lock held 225 * guarantees that the current callout will not run. 226 * The softclock_call_cc() function sets this to 0 before it 227 * drops callout_lock to acquire c_lock, and it calls 228 * the handler only if curr_cancelled is still 0 after 229 * cc_lock is successfully acquired. 230 * cc_waiting - If a thread is waiting in callout_drain(), then 231 * callout_wait is nonzero. Set only when 232 * cc_curr is non-NULL. 233 */ 234 235 /* 236 * Resets the execution entity tied to a specific callout cpu. 237 */ 238 static void 239 cc_cce_cleanup(struct callout_cpu *cc, int direct) 240 { 241 242 cc_exec_curr(cc, direct) = NULL; 243 cc_exec_cancel(cc, direct) = false; 244 cc_exec_waiting(cc, direct) = false; 245 #ifdef SMP 246 cc_migration_cpu(cc, direct) = CPUBLOCK; 247 cc_migration_time(cc, direct) = 0; 248 cc_migration_prec(cc, direct) = 0; 249 cc_migration_func(cc, direct) = NULL; 250 cc_migration_arg(cc, direct) = NULL; 251 #endif 252 } 253 254 /* 255 * Checks if migration is requested by a specific callout cpu. 256 */ 257 static int 258 cc_cce_migrating(struct callout_cpu *cc, int direct) 259 { 260 261 #ifdef SMP 262 return (cc_migration_cpu(cc, direct) != CPUBLOCK); 263 #else 264 return (0); 265 #endif 266 } 267 268 /* 269 * Kernel low level callwheel initialization 270 * called on the BSP during kernel startup. 271 */ 272 static void 273 callout_callwheel_init(void *dummy) 274 { 275 struct callout_cpu *cc; 276 int cpu; 277 278 /* 279 * Calculate the size of the callout wheel and the preallocated 280 * timeout() structures. 281 * XXX: Clip callout to result of previous function of maxusers 282 * maximum 384. This is still huge, but acceptable. 283 */ 284 ncallout = imin(16 + maxproc + maxfiles, 18508); 285 TUNABLE_INT_FETCH("kern.ncallout", &ncallout); 286 287 /* 288 * Calculate callout wheel size, should be next power of two higher 289 * than 'ncallout'. 290 */ 291 callwheelsize = 1 << fls(ncallout); 292 callwheelmask = callwheelsize - 1; 293 294 /* 295 * Fetch whether we're pinning the swi's or not. 296 */ 297 TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi); 298 TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi); 299 300 /* 301 * Initialize callout wheels. The software interrupt threads 302 * are created later. 303 */ 304 cc_default_cpu = PCPU_GET(cpuid); 305 CPU_FOREACH(cpu) { 306 cc = CC_CPU(cpu); 307 callout_cpu_init(cc, cpu); 308 } 309 } 310 SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); 311 312 /* 313 * Initialize the per-cpu callout structures. 314 */ 315 static void 316 callout_cpu_init(struct callout_cpu *cc, int cpu) 317 { 318 int i; 319 320 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN); 321 cc->cc_callwheel = malloc_domainset(sizeof(struct callout_list) * 322 callwheelsize, M_CALLOUT, 323 DOMAINSET_PREF(pcpu_find(cpu)->pc_domain), M_WAITOK); 324 for (i = 0; i < callwheelsize; i++) 325 LIST_INIT(&cc->cc_callwheel[i]); 326 TAILQ_INIT(&cc->cc_expireq); 327 cc->cc_firstevent = SBT_MAX; 328 for (i = 0; i < 2; i++) 329 cc_cce_cleanup(cc, i); 330 #ifdef KTR 331 snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name), 332 "callwheel cpu %d", cpu); 333 #endif 334 } 335 336 #ifdef SMP 337 /* 338 * Switches the cpu tied to a specific callout. 339 * The function expects a locked incoming callout cpu and returns with 340 * locked outcoming callout cpu. 341 */ 342 static struct callout_cpu * 343 callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu) 344 { 345 struct callout_cpu *new_cc; 346 347 MPASS(c != NULL && cc != NULL); 348 CC_LOCK_ASSERT(cc); 349 350 /* 351 * Avoid interrupts and preemption firing after the callout cpu 352 * is blocked in order to avoid deadlocks as the new thread 353 * may be willing to acquire the callout cpu lock. 354 */ 355 c->c_cpu = CPUBLOCK; 356 spinlock_enter(); 357 CC_UNLOCK(cc); 358 new_cc = CC_CPU(new_cpu); 359 CC_LOCK(new_cc); 360 spinlock_exit(); 361 c->c_cpu = new_cpu; 362 return (new_cc); 363 } 364 #endif 365 366 /* 367 * Start softclock threads. 368 */ 369 static void 370 start_softclock(void *dummy) 371 { 372 struct proc *p; 373 struct thread *td; 374 struct callout_cpu *cc; 375 int cpu, error; 376 bool pin_swi; 377 378 p = NULL; 379 CPU_FOREACH(cpu) { 380 cc = CC_CPU(cpu); 381 error = kproc_kthread_add(softclock_thread, cc, &p, &td, 382 RFSTOPPED, 0, "clock", "clock (%d)", cpu); 383 if (error != 0) 384 panic("failed to create softclock thread for cpu %d: %d", 385 cpu, error); 386 CC_LOCK(cc); 387 cc->cc_thread = td; 388 thread_lock(td); 389 sched_class(td, PRI_ITHD); 390 sched_ithread_prio(td, PI_SOFTCLOCK); 391 TD_SET_IWAIT(td); 392 thread_lock_set(td, (struct mtx *)&cc->cc_lock); 393 thread_unlock(td); 394 if (cpu == cc_default_cpu) 395 pin_swi = pin_default_swi; 396 else 397 pin_swi = pin_pcpu_swi; 398 if (pin_swi) { 399 error = cpuset_setithread(td->td_tid, cpu); 400 if (error != 0) 401 printf("%s: %s clock couldn't be pinned to cpu %d: %d\n", 402 __func__, cpu == cc_default_cpu ? 403 "default" : "per-cpu", cpu, error); 404 } 405 } 406 } 407 SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); 408 409 #define CC_HASH_SHIFT 8 410 411 static inline u_int 412 callout_hash(sbintime_t sbt) 413 { 414 415 return (sbt >> (32 - CC_HASH_SHIFT)); 416 } 417 418 static inline u_int 419 callout_get_bucket(sbintime_t sbt) 420 { 421 422 return (callout_hash(sbt) & callwheelmask); 423 } 424 425 void 426 callout_process(sbintime_t now) 427 { 428 struct callout_entropy { 429 struct callout_cpu *cc; 430 struct thread *td; 431 sbintime_t now; 432 } entropy; 433 struct callout *c, *next; 434 struct callout_cpu *cc; 435 struct callout_list *sc; 436 struct thread *td; 437 sbintime_t first, last, lookahead, max, tmp_max; 438 u_int firstb, lastb, nowb; 439 #ifdef CALLOUT_PROFILING 440 int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0; 441 #endif 442 443 cc = CC_SELF(); 444 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET); 445 446 /* Compute the buckets of the last scan and present times. */ 447 firstb = callout_hash(cc->cc_lastscan); 448 cc->cc_lastscan = now; 449 nowb = callout_hash(now); 450 451 /* Compute the last bucket and minimum time of the bucket after it. */ 452 if (nowb == firstb) 453 lookahead = (SBT_1S / 16); 454 else if (nowb - firstb == 1) 455 lookahead = (SBT_1S / 8); 456 else 457 lookahead = SBT_1S; 458 first = last = now; 459 first += (lookahead / 2); 460 last += lookahead; 461 last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); 462 lastb = callout_hash(last) - 1; 463 max = last; 464 465 /* 466 * Check if we wrapped around the entire wheel from the last scan. 467 * In case, we need to scan entirely the wheel for pending callouts. 468 */ 469 if (lastb - firstb >= callwheelsize) { 470 lastb = firstb + callwheelsize - 1; 471 if (nowb - firstb >= callwheelsize) 472 nowb = lastb; 473 } 474 475 /* Iterate callwheel from firstb to nowb and then up to lastb. */ 476 do { 477 sc = &cc->cc_callwheel[firstb & callwheelmask]; 478 LIST_FOREACH_SAFE(c, sc, c_links.le, next) { 479 /* Run the callout if present time within allowed. */ 480 if (c->c_time <= now) { 481 /* 482 * Consumer told us the callout may be run 483 * directly from hardware interrupt context. 484 */ 485 if (c->c_iflags & CALLOUT_DIRECT) { 486 #ifdef CALLOUT_PROFILING 487 ++depth_dir; 488 #endif 489 cc_exec_next(cc) = next; 490 cc->cc_bucket = firstb & callwheelmask; 491 LIST_REMOVE(c, c_links.le); 492 softclock_call_cc(c, cc, 493 #ifdef CALLOUT_PROFILING 494 &mpcalls_dir, &lockcalls_dir, NULL, 495 #endif 496 1); 497 next = cc_exec_next(cc); 498 cc_exec_next(cc) = NULL; 499 } else { 500 LIST_REMOVE(c, c_links.le); 501 TAILQ_INSERT_TAIL(&cc->cc_expireq, 502 c, c_links.tqe); 503 c->c_iflags |= CALLOUT_PROCESSED; 504 } 505 } else if (c->c_time >= max) { 506 /* 507 * Skip events in the distant future. 508 */ 509 ; 510 } else if (c->c_time > last) { 511 /* 512 * Event minimal time is bigger than present 513 * maximal time, so it cannot be aggregated. 514 */ 515 lastb = nowb; 516 } else { 517 /* 518 * Update first and last time, respecting this 519 * event. 520 */ 521 if (c->c_time < first) 522 first = c->c_time; 523 tmp_max = c->c_time + c->c_precision; 524 if (tmp_max < last) 525 last = tmp_max; 526 } 527 } 528 /* Proceed with the next bucket. */ 529 firstb++; 530 /* 531 * Stop if we looked after present time and found 532 * some event we can't execute at now. 533 * Stop if we looked far enough into the future. 534 */ 535 } while (((int)(firstb - lastb)) <= 0); 536 cc->cc_firstevent = last; 537 cpu_new_callout(curcpu, last, first); 538 539 #ifdef CALLOUT_PROFILING 540 avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8; 541 avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8; 542 avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8; 543 #endif 544 if (!TAILQ_EMPTY(&cc->cc_expireq)) { 545 entropy.cc = cc; 546 entropy.td = curthread; 547 entropy.now = now; 548 random_harvest_queue(&entropy, sizeof(entropy), RANDOM_CALLOUT); 549 550 td = cc->cc_thread; 551 if (TD_AWAITING_INTR(td)) { 552 thread_lock_block_wait(td); 553 THREAD_LOCK_ASSERT(td, MA_OWNED); 554 TD_CLR_IWAIT(td); 555 sched_wakeup(td, SRQ_INTR); 556 } else 557 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 558 } else 559 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 560 } 561 562 static struct callout_cpu * 563 callout_lock(struct callout *c) 564 { 565 struct callout_cpu *cc; 566 int cpu; 567 568 for (;;) { 569 cpu = c->c_cpu; 570 #ifdef SMP 571 if (cpu == CPUBLOCK) { 572 while (c->c_cpu == CPUBLOCK) 573 cpu_spinwait(); 574 continue; 575 } 576 #endif 577 cc = CC_CPU(cpu); 578 CC_LOCK(cc); 579 if (cpu == c->c_cpu) 580 break; 581 CC_UNLOCK(cc); 582 } 583 return (cc); 584 } 585 586 static void 587 callout_cc_add(struct callout *c, struct callout_cpu *cc, 588 sbintime_t sbt, sbintime_t precision, void (*func)(void *), 589 void *arg, int flags) 590 { 591 int bucket; 592 593 CC_LOCK_ASSERT(cc); 594 if (sbt < cc->cc_lastscan) 595 sbt = cc->cc_lastscan; 596 c->c_arg = arg; 597 c->c_iflags |= CALLOUT_PENDING; 598 c->c_iflags &= ~CALLOUT_PROCESSED; 599 c->c_flags |= CALLOUT_ACTIVE; 600 if (flags & C_DIRECT_EXEC) 601 c->c_iflags |= CALLOUT_DIRECT; 602 c->c_func = func; 603 c->c_time = sbt; 604 c->c_precision = precision; 605 bucket = callout_get_bucket(c->c_time); 606 CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x", 607 c, (int)(c->c_precision >> 32), 608 (u_int)(c->c_precision & 0xffffffff)); 609 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); 610 if (cc->cc_bucket == bucket) 611 cc_exec_next(cc) = c; 612 613 /* 614 * Inform the eventtimers(4) subsystem there's a new callout 615 * that has been inserted, but only if really required. 616 */ 617 if (SBT_MAX - c->c_time < c->c_precision) 618 c->c_precision = SBT_MAX - c->c_time; 619 sbt = c->c_time + c->c_precision; 620 if (sbt < cc->cc_firstevent) { 621 cc->cc_firstevent = sbt; 622 cpu_new_callout(c->c_cpu, sbt, c->c_time); 623 } 624 } 625 626 static void 627 softclock_call_cc(struct callout *c, struct callout_cpu *cc, 628 #ifdef CALLOUT_PROFILING 629 int *mpcalls, int *lockcalls, int *gcalls, 630 #endif 631 int direct) 632 { 633 struct rm_priotracker tracker; 634 callout_func_t *c_func, *drain; 635 void *c_arg; 636 struct lock_class *class; 637 struct lock_object *c_lock; 638 uintptr_t lock_status; 639 int c_iflags; 640 #ifdef SMP 641 struct callout_cpu *new_cc; 642 callout_func_t *new_func; 643 void *new_arg; 644 int flags, new_cpu; 645 sbintime_t new_prec, new_time; 646 #endif 647 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 648 sbintime_t sbt1, sbt2; 649 struct timespec ts2; 650 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 651 static callout_func_t *lastfunc; 652 #endif 653 654 KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING, 655 ("softclock_call_cc: pend %p %x", c, c->c_iflags)); 656 KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE, 657 ("softclock_call_cc: act %p %x", c, c->c_flags)); 658 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; 659 lock_status = 0; 660 if (c->c_iflags & CALLOUT_SHAREDLOCK) { 661 if (class == &lock_class_rm) 662 lock_status = (uintptr_t)&tracker; 663 else 664 lock_status = 1; 665 } 666 c_lock = c->c_lock; 667 c_func = c->c_func; 668 c_arg = c->c_arg; 669 c_iflags = c->c_iflags; 670 c->c_iflags &= ~CALLOUT_PENDING; 671 672 cc_exec_curr(cc, direct) = c; 673 cc_exec_last_func(cc, direct) = c_func; 674 cc_exec_last_arg(cc, direct) = c_arg; 675 cc_exec_cancel(cc, direct) = false; 676 cc_exec_drain(cc, direct) = NULL; 677 CC_UNLOCK(cc); 678 if (c_lock != NULL) { 679 class->lc_lock(c_lock, lock_status); 680 /* 681 * The callout may have been cancelled 682 * while we switched locks. 683 */ 684 if (cc_exec_cancel(cc, direct)) { 685 class->lc_unlock(c_lock); 686 goto skip; 687 } 688 /* The callout cannot be stopped now. */ 689 cc_exec_cancel(cc, direct) = true; 690 if (c_lock == &Giant.lock_object) { 691 #ifdef CALLOUT_PROFILING 692 (*gcalls)++; 693 #endif 694 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", 695 c, c_func, c_arg); 696 } else { 697 #ifdef CALLOUT_PROFILING 698 (*lockcalls)++; 699 #endif 700 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", 701 c, c_func, c_arg); 702 } 703 } else { 704 #ifdef CALLOUT_PROFILING 705 (*mpcalls)++; 706 #endif 707 CTR3(KTR_CALLOUT, "callout %p func %p arg %p", 708 c, c_func, c_arg); 709 } 710 KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running", 711 "func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct); 712 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 713 sbt1 = sbinuptime(); 714 #endif 715 THREAD_NO_SLEEPING(); 716 SDT_PROBE1(callout_execute, , , callout__start, c); 717 c_func(c_arg); 718 SDT_PROBE1(callout_execute, , , callout__end, c); 719 THREAD_SLEEPING_OK(); 720 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 721 sbt2 = sbinuptime(); 722 sbt2 -= sbt1; 723 if (sbt2 > maxdt) { 724 if (lastfunc != c_func || sbt2 > maxdt * 2) { 725 ts2 = sbttots(sbt2); 726 printf( 727 "Expensive callout(9) function: %p(%p) %jd.%09ld s\n", 728 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); 729 } 730 maxdt = sbt2; 731 lastfunc = c_func; 732 } 733 #endif 734 KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle"); 735 CTR1(KTR_CALLOUT, "callout %p finished", c); 736 if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0) 737 class->lc_unlock(c_lock); 738 skip: 739 CC_LOCK(cc); 740 KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr")); 741 cc_exec_curr(cc, direct) = NULL; 742 if (cc_exec_drain(cc, direct)) { 743 drain = cc_exec_drain(cc, direct); 744 cc_exec_drain(cc, direct) = NULL; 745 CC_UNLOCK(cc); 746 drain(c_arg); 747 CC_LOCK(cc); 748 } 749 if (cc_exec_waiting(cc, direct)) { 750 /* 751 * There is someone waiting for the 752 * callout to complete. 753 * If the callout was scheduled for 754 * migration just cancel it. 755 */ 756 if (cc_cce_migrating(cc, direct)) { 757 cc_cce_cleanup(cc, direct); 758 759 /* 760 * It should be assert here that the callout is not 761 * destroyed but that is not easy. 762 */ 763 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 764 } 765 cc_exec_waiting(cc, direct) = false; 766 CC_UNLOCK(cc); 767 wakeup(&cc_exec_waiting(cc, direct)); 768 CC_LOCK(cc); 769 } else if (cc_cce_migrating(cc, direct)) { 770 #ifdef SMP 771 /* 772 * If the callout was scheduled for 773 * migration just perform it now. 774 */ 775 new_cpu = cc_migration_cpu(cc, direct); 776 new_time = cc_migration_time(cc, direct); 777 new_prec = cc_migration_prec(cc, direct); 778 new_func = cc_migration_func(cc, direct); 779 new_arg = cc_migration_arg(cc, direct); 780 cc_cce_cleanup(cc, direct); 781 782 /* 783 * It should be assert here that the callout is not destroyed 784 * but that is not easy. 785 * 786 * As first thing, handle deferred callout stops. 787 */ 788 if (!callout_migrating(c)) { 789 CTR3(KTR_CALLOUT, 790 "deferred cancelled %p func %p arg %p", 791 c, new_func, new_arg); 792 return; 793 } 794 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 795 796 new_cc = callout_cpu_switch(c, cc, new_cpu); 797 flags = (direct) ? C_DIRECT_EXEC : 0; 798 callout_cc_add(c, new_cc, new_time, new_prec, new_func, 799 new_arg, flags); 800 CC_UNLOCK(new_cc); 801 CC_LOCK(cc); 802 #else 803 panic("migration should not happen"); 804 #endif 805 } 806 } 807 808 /* 809 * The callout mechanism is based on the work of Adam M. Costello and 810 * George Varghese, published in a technical report entitled "Redesigning 811 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 812 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 813 * used in this implementation was published by G. Varghese and T. Lauck in 814 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 815 * the Efficient Implementation of a Timer Facility" in the Proceedings of 816 * the 11th ACM Annual Symposium on Operating Systems Principles, 817 * Austin, Texas Nov 1987. 818 */ 819 820 /* 821 * Software (low priority) clock interrupt thread handler. 822 * Run periodic events from timeout queue. 823 */ 824 static void 825 softclock_thread(void *arg) 826 { 827 struct thread *td = curthread; 828 struct callout_cpu *cc; 829 struct callout *c; 830 #ifdef CALLOUT_PROFILING 831 int depth, gcalls, lockcalls, mpcalls; 832 #endif 833 834 cc = (struct callout_cpu *)arg; 835 CC_LOCK(cc); 836 for (;;) { 837 while (TAILQ_EMPTY(&cc->cc_expireq)) { 838 /* 839 * Use CC_LOCK(cc) as the thread_lock while 840 * idle. 841 */ 842 thread_lock(td); 843 thread_lock_set(td, (struct mtx *)&cc->cc_lock); 844 TD_SET_IWAIT(td); 845 mi_switch(SW_VOL | SWT_IWAIT); 846 847 /* mi_switch() drops thread_lock(). */ 848 CC_LOCK(cc); 849 } 850 851 #ifdef CALLOUT_PROFILING 852 depth = gcalls = lockcalls = mpcalls = 0; 853 #endif 854 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { 855 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 856 softclock_call_cc(c, cc, 857 #ifdef CALLOUT_PROFILING 858 &mpcalls, &lockcalls, &gcalls, 859 #endif 860 0); 861 #ifdef CALLOUT_PROFILING 862 ++depth; 863 #endif 864 } 865 #ifdef CALLOUT_PROFILING 866 avg_depth += (depth * 1000 - avg_depth) >> 8; 867 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 868 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 869 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 870 #endif 871 } 872 } 873 874 void 875 callout_when(sbintime_t sbt, sbintime_t precision, int flags, 876 sbintime_t *res, sbintime_t *prec_res) 877 { 878 sbintime_t to_sbt, to_pr; 879 880 if ((flags & (C_ABSOLUTE | C_PRECALC)) != 0) { 881 *res = sbt; 882 *prec_res = precision; 883 return; 884 } 885 if ((flags & C_HARDCLOCK) != 0 && sbt < tick_sbt) 886 sbt = tick_sbt; 887 if ((flags & C_HARDCLOCK) != 0 || sbt >= sbt_tickthreshold) { 888 /* 889 * Obtain the time of the last hardclock() call on 890 * this CPU directly from the kern_clocksource.c. 891 * This value is per-CPU, but it is equal for all 892 * active ones. 893 */ 894 #ifdef __LP64__ 895 to_sbt = DPCPU_GET(hardclocktime); 896 #else 897 spinlock_enter(); 898 to_sbt = DPCPU_GET(hardclocktime); 899 spinlock_exit(); 900 #endif 901 if (cold && to_sbt == 0) 902 to_sbt = sbinuptime(); 903 if ((flags & C_HARDCLOCK) == 0) 904 to_sbt += tick_sbt; 905 } else 906 to_sbt = sbinuptime(); 907 if (SBT_MAX - to_sbt < sbt) 908 to_sbt = SBT_MAX; 909 else 910 to_sbt += sbt; 911 *res = to_sbt; 912 to_pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : 913 sbt >> C_PRELGET(flags)); 914 *prec_res = to_pr > precision ? to_pr : precision; 915 } 916 917 /* 918 * New interface; clients allocate their own callout structures. 919 * 920 * callout_reset() - establish or change a timeout 921 * callout_stop() - disestablish a timeout 922 * callout_init() - initialize a callout structure so that it can 923 * safely be passed to callout_reset() and callout_stop() 924 * 925 * <sys/callout.h> defines three convenience macros: 926 * 927 * callout_active() - returns truth if callout has not been stopped, 928 * drained, or deactivated since the last time the callout was 929 * reset. 930 * callout_pending() - returns truth if callout is still waiting for timeout 931 * callout_deactivate() - marks the callout as having been serviced 932 */ 933 int 934 callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t prec, 935 callout_func_t *ftn, void *arg, int cpu, int flags) 936 { 937 sbintime_t to_sbt, precision; 938 struct callout_cpu *cc; 939 int cancelled, direct; 940 941 cancelled = 0; 942 callout_when(sbt, prec, flags, &to_sbt, &precision); 943 944 /* 945 * This flag used to be added by callout_cc_add, but the 946 * first time you call this we could end up with the 947 * wrong direct flag if we don't do it before we add. 948 */ 949 if (flags & C_DIRECT_EXEC) { 950 direct = 1; 951 } else { 952 direct = 0; 953 } 954 KASSERT(!direct || c->c_lock == NULL || 955 (LOCK_CLASS(c->c_lock)->lc_flags & LC_SPINLOCK), 956 ("%s: direct callout %p has non-spin lock", __func__, c)); 957 958 cc = callout_lock(c); 959 if (cpu == -1) 960 cpu = c->c_cpu; 961 KASSERT(cpu >= 0 && cpu <= mp_maxid && !CPU_ABSENT(cpu), 962 ("%s: invalid cpu %d", __func__, cpu)); 963 964 if (cc_exec_curr(cc, direct) == c) { 965 /* 966 * We're being asked to reschedule a callout which is 967 * currently in progress. If there is a lock then we 968 * can cancel the callout if it has not really started. 969 */ 970 if (c->c_lock != NULL && !cc_exec_cancel(cc, direct)) 971 cancelled = cc_exec_cancel(cc, direct) = true; 972 if (cc_exec_waiting(cc, direct) || cc_exec_drain(cc, direct)) { 973 /* 974 * Someone has called callout_drain to kill this 975 * callout. Don't reschedule. 976 */ 977 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 978 cancelled ? "cancelled" : "failed to cancel", 979 c, c->c_func, c->c_arg); 980 CC_UNLOCK(cc); 981 return (cancelled); 982 } 983 #ifdef SMP 984 if (callout_migrating(c)) { 985 /* 986 * This only occurs when a second callout_reset_sbt_on 987 * is made after a previous one moved it into 988 * deferred migration (below). Note we do *not* change 989 * the prev_cpu even though the previous target may 990 * be different. 991 */ 992 cc_migration_cpu(cc, direct) = cpu; 993 cc_migration_time(cc, direct) = to_sbt; 994 cc_migration_prec(cc, direct) = precision; 995 cc_migration_func(cc, direct) = ftn; 996 cc_migration_arg(cc, direct) = arg; 997 cancelled = 1; 998 CC_UNLOCK(cc); 999 return (cancelled); 1000 } 1001 #endif 1002 } 1003 if (c->c_iflags & CALLOUT_PENDING) { 1004 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1005 if (cc_exec_next(cc) == c) 1006 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1007 LIST_REMOVE(c, c_links.le); 1008 } else { 1009 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1010 } 1011 cancelled = 1; 1012 c->c_iflags &= ~ CALLOUT_PENDING; 1013 c->c_flags &= ~ CALLOUT_ACTIVE; 1014 } 1015 1016 #ifdef SMP 1017 /* 1018 * If the callout must migrate try to perform it immediately. 1019 * If the callout is currently running, just defer the migration 1020 * to a more appropriate moment. 1021 */ 1022 if (c->c_cpu != cpu) { 1023 if (cc_exec_curr(cc, direct) == c) { 1024 /* 1025 * Pending will have been removed since we are 1026 * actually executing the callout on another 1027 * CPU. That callout should be waiting on the 1028 * lock the caller holds. If we set both 1029 * active/and/pending after we return and the 1030 * lock on the executing callout proceeds, it 1031 * will then see pending is true and return. 1032 * At the return from the actual callout execution 1033 * the migration will occur in softclock_call_cc 1034 * and this new callout will be placed on the 1035 * new CPU via a call to callout_cpu_switch() which 1036 * will get the lock on the right CPU followed 1037 * by a call callout_cc_add() which will add it there. 1038 * (see above in softclock_call_cc()). 1039 */ 1040 cc_migration_cpu(cc, direct) = cpu; 1041 cc_migration_time(cc, direct) = to_sbt; 1042 cc_migration_prec(cc, direct) = precision; 1043 cc_migration_func(cc, direct) = ftn; 1044 cc_migration_arg(cc, direct) = arg; 1045 c->c_iflags |= (CALLOUT_DFRMIGRATION | CALLOUT_PENDING); 1046 c->c_flags |= CALLOUT_ACTIVE; 1047 CTR6(KTR_CALLOUT, 1048 "migration of %p func %p arg %p in %d.%08x to %u deferred", 1049 c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1050 (u_int)(to_sbt & 0xffffffff), cpu); 1051 CC_UNLOCK(cc); 1052 return (cancelled); 1053 } 1054 cc = callout_cpu_switch(c, cc, cpu); 1055 } 1056 #endif 1057 1058 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, flags); 1059 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", 1060 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1061 (u_int)(to_sbt & 0xffffffff)); 1062 CC_UNLOCK(cc); 1063 1064 return (cancelled); 1065 } 1066 1067 /* 1068 * Common idioms that can be optimized in the future. 1069 */ 1070 int 1071 callout_schedule_on(struct callout *c, int to_ticks, int cpu) 1072 { 1073 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 1074 } 1075 1076 int 1077 callout_schedule(struct callout *c, int to_ticks) 1078 { 1079 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 1080 } 1081 1082 int 1083 _callout_stop_safe(struct callout *c, int flags, callout_func_t *drain) 1084 { 1085 struct callout_cpu *cc, *old_cc; 1086 struct lock_class *class; 1087 int direct, sq_locked, use_lock; 1088 int cancelled, not_on_a_list; 1089 1090 if ((flags & CS_DRAIN) != 0) 1091 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock, 1092 "calling %s", __func__); 1093 1094 KASSERT((flags & CS_DRAIN) == 0 || drain == NULL, 1095 ("Cannot set drain callback and CS_DRAIN flag at the same time")); 1096 1097 /* 1098 * Some old subsystems don't hold Giant while running a callout_stop(), 1099 * so just discard this check for the moment. 1100 */ 1101 if ((flags & CS_DRAIN) == 0 && c->c_lock != NULL) { 1102 if (c->c_lock == &Giant.lock_object) 1103 use_lock = mtx_owned(&Giant); 1104 else { 1105 use_lock = 1; 1106 class = LOCK_CLASS(c->c_lock); 1107 class->lc_assert(c->c_lock, LA_XLOCKED); 1108 } 1109 } else 1110 use_lock = 0; 1111 if (c->c_iflags & CALLOUT_DIRECT) { 1112 direct = 1; 1113 } else { 1114 direct = 0; 1115 } 1116 sq_locked = 0; 1117 old_cc = NULL; 1118 again: 1119 cc = callout_lock(c); 1120 1121 if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) == 1122 (CALLOUT_DFRMIGRATION | CALLOUT_PENDING) && 1123 ((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) { 1124 /* 1125 * Special case where this slipped in while we 1126 * were migrating *as* the callout is about to 1127 * execute. The caller probably holds the lock 1128 * the callout wants. 1129 * 1130 * Get rid of the migration first. Then set 1131 * the flag that tells this code *not* to 1132 * try to remove it from any lists (its not 1133 * on one yet). When the callout wheel runs, 1134 * it will ignore this callout. 1135 */ 1136 c->c_iflags &= ~CALLOUT_PENDING; 1137 c->c_flags &= ~CALLOUT_ACTIVE; 1138 not_on_a_list = 1; 1139 } else { 1140 not_on_a_list = 0; 1141 } 1142 1143 /* 1144 * If the callout was migrating while the callout cpu lock was 1145 * dropped, just drop the sleepqueue lock and check the states 1146 * again. 1147 */ 1148 if (sq_locked != 0 && cc != old_cc) { 1149 #ifdef SMP 1150 CC_UNLOCK(cc); 1151 sleepq_release(&cc_exec_waiting(old_cc, direct)); 1152 sq_locked = 0; 1153 old_cc = NULL; 1154 goto again; 1155 #else 1156 panic("migration should not happen"); 1157 #endif 1158 } 1159 1160 /* 1161 * If the callout is running, try to stop it or drain it. 1162 */ 1163 if (cc_exec_curr(cc, direct) == c) { 1164 /* 1165 * Succeed we to stop it or not, we must clear the 1166 * active flag - this is what API users expect. If we're 1167 * draining and the callout is currently executing, first wait 1168 * until it finishes. 1169 */ 1170 if ((flags & CS_DRAIN) == 0) 1171 c->c_flags &= ~CALLOUT_ACTIVE; 1172 1173 if ((flags & CS_DRAIN) != 0) { 1174 /* 1175 * The current callout is running (or just 1176 * about to run) and blocking is allowed, so 1177 * just wait for the current invocation to 1178 * finish. 1179 */ 1180 if (cc_exec_curr(cc, direct) == c) { 1181 /* 1182 * Use direct calls to sleepqueue interface 1183 * instead of cv/msleep in order to avoid 1184 * a LOR between cc_lock and sleepqueue 1185 * chain spinlocks. This piece of code 1186 * emulates a msleep_spin() call actually. 1187 * 1188 * If we already have the sleepqueue chain 1189 * locked, then we can safely block. If we 1190 * don't already have it locked, however, 1191 * we have to drop the cc_lock to lock 1192 * it. This opens several races, so we 1193 * restart at the beginning once we have 1194 * both locks. If nothing has changed, then 1195 * we will end up back here with sq_locked 1196 * set. 1197 */ 1198 if (!sq_locked) { 1199 CC_UNLOCK(cc); 1200 sleepq_lock( 1201 &cc_exec_waiting(cc, direct)); 1202 sq_locked = 1; 1203 old_cc = cc; 1204 goto again; 1205 } 1206 1207 /* 1208 * Migration could be cancelled here, but 1209 * as long as it is still not sure when it 1210 * will be packed up, just let softclock() 1211 * take care of it. 1212 */ 1213 cc_exec_waiting(cc, direct) = true; 1214 DROP_GIANT(); 1215 CC_UNLOCK(cc); 1216 sleepq_add( 1217 &cc_exec_waiting(cc, direct), 1218 &cc->cc_lock.lock_object, "codrain", 1219 SLEEPQ_SLEEP, 0); 1220 sleepq_wait( 1221 &cc_exec_waiting(cc, direct), 1222 0); 1223 sq_locked = 0; 1224 old_cc = NULL; 1225 1226 /* Reacquire locks previously released. */ 1227 PICKUP_GIANT(); 1228 goto again; 1229 } 1230 c->c_flags &= ~CALLOUT_ACTIVE; 1231 } else if (use_lock && 1232 !cc_exec_cancel(cc, direct) && (drain == NULL)) { 1233 1234 /* 1235 * The current callout is waiting for its 1236 * lock which we hold. Cancel the callout 1237 * and return. After our caller drops the 1238 * lock, the callout will be skipped in 1239 * softclock(). This *only* works with a 1240 * callout_stop() *not* callout_drain() or 1241 * callout_async_drain(). 1242 */ 1243 cc_exec_cancel(cc, direct) = true; 1244 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1245 c, c->c_func, c->c_arg); 1246 KASSERT(!cc_cce_migrating(cc, direct), 1247 ("callout wrongly scheduled for migration")); 1248 if (callout_migrating(c)) { 1249 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1250 #ifdef SMP 1251 cc_migration_cpu(cc, direct) = CPUBLOCK; 1252 cc_migration_time(cc, direct) = 0; 1253 cc_migration_prec(cc, direct) = 0; 1254 cc_migration_func(cc, direct) = NULL; 1255 cc_migration_arg(cc, direct) = NULL; 1256 #endif 1257 } 1258 CC_UNLOCK(cc); 1259 KASSERT(!sq_locked, ("sleepqueue chain locked")); 1260 return (1); 1261 } else if (callout_migrating(c)) { 1262 /* 1263 * The callout is currently being serviced 1264 * and the "next" callout is scheduled at 1265 * its completion with a migration. We remove 1266 * the migration flag so it *won't* get rescheduled, 1267 * but we can't stop the one thats running so 1268 * we return 0. 1269 */ 1270 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1271 #ifdef SMP 1272 /* 1273 * We can't call cc_cce_cleanup here since 1274 * if we do it will remove .ce_curr and 1275 * its still running. This will prevent a 1276 * reschedule of the callout when the 1277 * execution completes. 1278 */ 1279 cc_migration_cpu(cc, direct) = CPUBLOCK; 1280 cc_migration_time(cc, direct) = 0; 1281 cc_migration_prec(cc, direct) = 0; 1282 cc_migration_func(cc, direct) = NULL; 1283 cc_migration_arg(cc, direct) = NULL; 1284 #endif 1285 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 1286 c, c->c_func, c->c_arg); 1287 if (drain) { 1288 KASSERT(cc_exec_drain(cc, direct) == NULL, 1289 ("callout drain function already set to %p", 1290 cc_exec_drain(cc, direct))); 1291 cc_exec_drain(cc, direct) = drain; 1292 } 1293 CC_UNLOCK(cc); 1294 return (0); 1295 } else { 1296 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1297 c, c->c_func, c->c_arg); 1298 if (drain) { 1299 KASSERT(cc_exec_drain(cc, direct) == NULL, 1300 ("callout drain function already set to %p", 1301 cc_exec_drain(cc, direct))); 1302 cc_exec_drain(cc, direct) = drain; 1303 } 1304 } 1305 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 1306 cancelled = 0; 1307 } else 1308 cancelled = 1; 1309 1310 if (sq_locked) 1311 sleepq_release(&cc_exec_waiting(cc, direct)); 1312 1313 if ((c->c_iflags & CALLOUT_PENDING) == 0) { 1314 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1315 c, c->c_func, c->c_arg); 1316 /* 1317 * For not scheduled and not executing callout return 1318 * negative value. 1319 */ 1320 if (cc_exec_curr(cc, direct) != c) 1321 cancelled = -1; 1322 CC_UNLOCK(cc); 1323 return (cancelled); 1324 } 1325 1326 c->c_iflags &= ~CALLOUT_PENDING; 1327 c->c_flags &= ~CALLOUT_ACTIVE; 1328 1329 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1330 c, c->c_func, c->c_arg); 1331 if (not_on_a_list == 0) { 1332 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1333 if (cc_exec_next(cc) == c) 1334 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1335 LIST_REMOVE(c, c_links.le); 1336 } else { 1337 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1338 } 1339 } 1340 CC_UNLOCK(cc); 1341 return (cancelled); 1342 } 1343 1344 void 1345 callout_init(struct callout *c, int mpsafe) 1346 { 1347 bzero(c, sizeof *c); 1348 if (mpsafe) { 1349 c->c_lock = NULL; 1350 c->c_iflags = CALLOUT_RETURNUNLOCKED; 1351 } else { 1352 c->c_lock = &Giant.lock_object; 1353 c->c_iflags = 0; 1354 } 1355 c->c_cpu = cc_default_cpu; 1356 } 1357 1358 void 1359 _callout_init_lock(struct callout *c, struct lock_object *lock, int flags) 1360 { 1361 bzero(c, sizeof *c); 1362 c->c_lock = lock; 1363 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1364 ("callout_init_lock: bad flags %d", flags)); 1365 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1366 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1367 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & LC_SLEEPABLE), 1368 ("%s: callout %p has sleepable lock", __func__, c)); 1369 c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1370 c->c_cpu = cc_default_cpu; 1371 } 1372 1373 static int 1374 flssbt(sbintime_t sbt) 1375 { 1376 1377 sbt += (uint64_t)sbt >> 1; 1378 if (sizeof(long) >= sizeof(sbintime_t)) 1379 return (flsl(sbt)); 1380 if (sbt >= SBT_1S) 1381 return (flsl(((uint64_t)sbt) >> 32) + 32); 1382 return (flsl(sbt)); 1383 } 1384 1385 /* 1386 * Dump immediate statistic snapshot of the scheduled callouts. 1387 */ 1388 static int 1389 sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1390 { 1391 struct callout *tmp; 1392 struct callout_cpu *cc; 1393 struct callout_list *sc; 1394 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; 1395 int ct[64], cpr[64], ccpbk[32]; 1396 int error, val, i, count, tcum, pcum, maxc, c, medc; 1397 int cpu; 1398 1399 val = 0; 1400 error = sysctl_handle_int(oidp, &val, 0, req); 1401 if (error != 0 || req->newptr == NULL) 1402 return (error); 1403 count = maxc = 0; 1404 st = spr = maxt = maxpr = 0; 1405 bzero(ccpbk, sizeof(ccpbk)); 1406 bzero(ct, sizeof(ct)); 1407 bzero(cpr, sizeof(cpr)); 1408 now = sbinuptime(); 1409 CPU_FOREACH(cpu) { 1410 cc = CC_CPU(cpu); 1411 CC_LOCK(cc); 1412 for (i = 0; i < callwheelsize; i++) { 1413 sc = &cc->cc_callwheel[i]; 1414 c = 0; 1415 LIST_FOREACH(tmp, sc, c_links.le) { 1416 c++; 1417 t = tmp->c_time - now; 1418 if (t < 0) 1419 t = 0; 1420 st += t / SBT_1US; 1421 spr += tmp->c_precision / SBT_1US; 1422 if (t > maxt) 1423 maxt = t; 1424 if (tmp->c_precision > maxpr) 1425 maxpr = tmp->c_precision; 1426 ct[flssbt(t)]++; 1427 cpr[flssbt(tmp->c_precision)]++; 1428 } 1429 if (c > maxc) 1430 maxc = c; 1431 ccpbk[fls(c + c / 2)]++; 1432 count += c; 1433 } 1434 CC_UNLOCK(cc); 1435 } 1436 1437 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1438 tcum += ct[i]; 1439 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1440 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) 1441 pcum += cpr[i]; 1442 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1443 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1444 c += ccpbk[i]; 1445 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1446 1447 printf("Scheduled callouts statistic snapshot:\n"); 1448 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1449 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1450 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1451 medc, 1452 count / callwheelsize / mp_ncpus, 1453 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1454 maxc); 1455 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1456 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1457 (st / count) / 1000000, (st / count) % 1000000, 1458 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); 1459 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1460 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, 1461 (spr / count) / 1000000, (spr / count) % 1000000, 1462 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); 1463 printf(" Distribution: \tbuckets\t time\t tcum\t" 1464 " prec\t pcum\n"); 1465 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1466 if (ct[i] == 0 && cpr[i] == 0) 1467 continue; 1468 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1469 tcum += ct[i]; 1470 pcum += cpr[i]; 1471 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", 1472 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1473 i - 1 - (32 - CC_HASH_SHIFT), 1474 ct[i], tcum, cpr[i], pcum); 1475 } 1476 return (error); 1477 } 1478 SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1479 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1480 0, 0, sysctl_kern_callout_stat, "I", 1481 "Dump immediate statistic snapshot of the scheduled callouts"); 1482 1483 #ifdef DDB 1484 static void 1485 _show_callout(struct callout *c) 1486 { 1487 1488 db_printf("callout %p\n", c); 1489 #define C_DB_PRINTF(f, e) db_printf(" %s = " f "\n", #e, c->e); 1490 db_printf(" &c_links = %p\n", &(c->c_links)); 1491 C_DB_PRINTF("%" PRId64, c_time); 1492 C_DB_PRINTF("%" PRId64, c_precision); 1493 C_DB_PRINTF("%p", c_arg); 1494 C_DB_PRINTF("%p", c_func); 1495 C_DB_PRINTF("%p", c_lock); 1496 C_DB_PRINTF("%#x", c_flags); 1497 C_DB_PRINTF("%#x", c_iflags); 1498 C_DB_PRINTF("%d", c_cpu); 1499 #undef C_DB_PRINTF 1500 } 1501 1502 DB_SHOW_COMMAND(callout, db_show_callout) 1503 { 1504 1505 if (!have_addr) { 1506 db_printf("usage: show callout <struct callout *>\n"); 1507 return; 1508 } 1509 1510 _show_callout((struct callout *)addr); 1511 } 1512 1513 static void 1514 _show_last_callout(int cpu, int direct, const char *dirstr) 1515 { 1516 struct callout_cpu *cc; 1517 void *func, *arg; 1518 1519 cc = CC_CPU(cpu); 1520 func = cc_exec_last_func(cc, direct); 1521 arg = cc_exec_last_arg(cc, direct); 1522 db_printf("cpu %d last%s callout function: %p ", cpu, dirstr, func); 1523 db_printsym((db_expr_t)func, DB_STGY_ANY); 1524 db_printf("\ncpu %d last%s callout argument: %p\n", cpu, dirstr, arg); 1525 } 1526 1527 DB_SHOW_COMMAND_FLAGS(callout_last, db_show_callout_last, DB_CMD_MEMSAFE) 1528 { 1529 int cpu, last; 1530 1531 if (have_addr) { 1532 if (addr < 0 || addr > mp_maxid || CPU_ABSENT(addr)) { 1533 db_printf("no such cpu: %d\n", (int)addr); 1534 return; 1535 } 1536 cpu = last = addr; 1537 } else { 1538 cpu = 0; 1539 last = mp_maxid; 1540 } 1541 1542 while (cpu <= last) { 1543 if (!CPU_ABSENT(cpu)) { 1544 _show_last_callout(cpu, 0, ""); 1545 _show_last_callout(cpu, 1, " direct"); 1546 } 1547 cpu++; 1548 } 1549 } 1550 #endif /* DDB */ 1551