1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include "opt_callout_profiling.h" 43 #include "opt_ddb.h" 44 #if defined(__arm__) 45 #include "opt_timer.h" 46 #endif 47 #include "opt_rss.h" 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/bus.h> 52 #include <sys/callout.h> 53 #include <sys/domainset.h> 54 #include <sys/file.h> 55 #include <sys/interrupt.h> 56 #include <sys/kernel.h> 57 #include <sys/ktr.h> 58 #include <sys/lock.h> 59 #include <sys/malloc.h> 60 #include <sys/mutex.h> 61 #include <sys/proc.h> 62 #include <sys/sdt.h> 63 #include <sys/sleepqueue.h> 64 #include <sys/sysctl.h> 65 #include <sys/smp.h> 66 67 #ifdef DDB 68 #include <ddb/ddb.h> 69 #include <ddb/db_sym.h> 70 #include <machine/_inttypes.h> 71 #endif 72 73 #ifdef SMP 74 #include <machine/cpu.h> 75 #endif 76 77 #ifndef NO_EVENTTIMERS 78 DPCPU_DECLARE(sbintime_t, hardclocktime); 79 #endif 80 81 SDT_PROVIDER_DEFINE(callout_execute); 82 SDT_PROBE_DEFINE1(callout_execute, , , callout__start, "struct callout *"); 83 SDT_PROBE_DEFINE1(callout_execute, , , callout__end, "struct callout *"); 84 85 #ifdef CALLOUT_PROFILING 86 static int avg_depth; 87 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, 88 "Average number of items examined per softclock call. Units = 1/1000"); 89 static int avg_gcalls; 90 SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, 91 "Average number of Giant callouts made per softclock call. Units = 1/1000"); 92 static int avg_lockcalls; 93 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0, 94 "Average number of lock callouts made per softclock call. Units = 1/1000"); 95 static int avg_mpcalls; 96 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, 97 "Average number of MP callouts made per softclock call. Units = 1/1000"); 98 static int avg_depth_dir; 99 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0, 100 "Average number of direct callouts examined per callout_process call. " 101 "Units = 1/1000"); 102 static int avg_lockcalls_dir; 103 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD, 104 &avg_lockcalls_dir, 0, "Average number of lock direct callouts made per " 105 "callout_process call. Units = 1/1000"); 106 static int avg_mpcalls_dir; 107 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir, 108 0, "Average number of MP direct callouts made per callout_process call. " 109 "Units = 1/1000"); 110 #endif 111 112 static int ncallout; 113 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &ncallout, 0, 114 "Number of entries in callwheel and size of timeout() preallocation"); 115 116 #ifdef RSS 117 static int pin_default_swi = 1; 118 static int pin_pcpu_swi = 1; 119 #else 120 static int pin_default_swi = 0; 121 static int pin_pcpu_swi = 0; 122 #endif 123 124 SYSCTL_INT(_kern, OID_AUTO, pin_default_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_default_swi, 125 0, "Pin the default (non-per-cpu) swi (shared with PCPU 0 swi)"); 126 SYSCTL_INT(_kern, OID_AUTO, pin_pcpu_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_pcpu_swi, 127 0, "Pin the per-CPU swis (except PCPU 0, which is also default"); 128 129 /* 130 * TODO: 131 * allocate more timeout table slots when table overflows. 132 */ 133 static u_int __read_mostly callwheelsize; 134 static u_int __read_mostly callwheelmask; 135 136 /* 137 * The callout cpu exec entities represent informations necessary for 138 * describing the state of callouts currently running on the CPU and the ones 139 * necessary for migrating callouts to the new callout cpu. In particular, 140 * the first entry of the array cc_exec_entity holds informations for callout 141 * running in SWI thread context, while the second one holds informations 142 * for callout running directly from hardware interrupt context. 143 * The cached informations are very important for deferring migration when 144 * the migrating callout is already running. 145 */ 146 struct cc_exec { 147 struct callout *cc_curr; 148 void (*cc_drain)(void *); 149 void *cc_last_func; 150 void *cc_last_arg; 151 #ifdef SMP 152 void (*ce_migration_func)(void *); 153 void *ce_migration_arg; 154 sbintime_t ce_migration_time; 155 sbintime_t ce_migration_prec; 156 int ce_migration_cpu; 157 #endif 158 bool cc_cancel; 159 bool cc_waiting; 160 }; 161 162 /* 163 * There is one struct callout_cpu per cpu, holding all relevant 164 * state for the callout processing thread on the individual CPU. 165 */ 166 struct callout_cpu { 167 struct mtx_padalign cc_lock; 168 struct cc_exec cc_exec_entity[2]; 169 struct callout *cc_next; 170 struct callout *cc_callout; 171 struct callout_list *cc_callwheel; 172 struct callout_tailq cc_expireq; 173 struct callout_slist cc_callfree; 174 sbintime_t cc_firstevent; 175 sbintime_t cc_lastscan; 176 void *cc_cookie; 177 u_int cc_bucket; 178 u_int cc_inited; 179 #ifdef KTR 180 char cc_ktr_event_name[20]; 181 #endif 182 }; 183 184 #define callout_migrating(c) ((c)->c_iflags & CALLOUT_DFRMIGRATION) 185 186 #define cc_exec_curr(cc, dir) cc->cc_exec_entity[dir].cc_curr 187 #define cc_exec_last_func(cc, dir) cc->cc_exec_entity[dir].cc_last_func 188 #define cc_exec_last_arg(cc, dir) cc->cc_exec_entity[dir].cc_last_arg 189 #define cc_exec_drain(cc, dir) cc->cc_exec_entity[dir].cc_drain 190 #define cc_exec_next(cc) cc->cc_next 191 #define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel 192 #define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting 193 #ifdef SMP 194 #define cc_migration_func(cc, dir) cc->cc_exec_entity[dir].ce_migration_func 195 #define cc_migration_arg(cc, dir) cc->cc_exec_entity[dir].ce_migration_arg 196 #define cc_migration_cpu(cc, dir) cc->cc_exec_entity[dir].ce_migration_cpu 197 #define cc_migration_time(cc, dir) cc->cc_exec_entity[dir].ce_migration_time 198 #define cc_migration_prec(cc, dir) cc->cc_exec_entity[dir].ce_migration_prec 199 200 struct callout_cpu cc_cpu[MAXCPU]; 201 #define CPUBLOCK MAXCPU 202 #define CC_CPU(cpu) (&cc_cpu[(cpu)]) 203 #define CC_SELF() CC_CPU(PCPU_GET(cpuid)) 204 #else 205 struct callout_cpu cc_cpu; 206 #define CC_CPU(cpu) &cc_cpu 207 #define CC_SELF() &cc_cpu 208 #endif 209 #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) 210 #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) 211 #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) 212 213 static int __read_mostly timeout_cpu; 214 215 static void callout_cpu_init(struct callout_cpu *cc, int cpu); 216 static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, 217 #ifdef CALLOUT_PROFILING 218 int *mpcalls, int *lockcalls, int *gcalls, 219 #endif 220 int direct); 221 222 static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); 223 224 /** 225 * Locked by cc_lock: 226 * cc_curr - If a callout is in progress, it is cc_curr. 227 * If cc_curr is non-NULL, threads waiting in 228 * callout_drain() will be woken up as soon as the 229 * relevant callout completes. 230 * cc_cancel - Changing to 1 with both callout_lock and cc_lock held 231 * guarantees that the current callout will not run. 232 * The softclock() function sets this to 0 before it 233 * drops callout_lock to acquire c_lock, and it calls 234 * the handler only if curr_cancelled is still 0 after 235 * cc_lock is successfully acquired. 236 * cc_waiting - If a thread is waiting in callout_drain(), then 237 * callout_wait is nonzero. Set only when 238 * cc_curr is non-NULL. 239 */ 240 241 /* 242 * Resets the execution entity tied to a specific callout cpu. 243 */ 244 static void 245 cc_cce_cleanup(struct callout_cpu *cc, int direct) 246 { 247 248 cc_exec_curr(cc, direct) = NULL; 249 cc_exec_cancel(cc, direct) = false; 250 cc_exec_waiting(cc, direct) = false; 251 #ifdef SMP 252 cc_migration_cpu(cc, direct) = CPUBLOCK; 253 cc_migration_time(cc, direct) = 0; 254 cc_migration_prec(cc, direct) = 0; 255 cc_migration_func(cc, direct) = NULL; 256 cc_migration_arg(cc, direct) = NULL; 257 #endif 258 } 259 260 /* 261 * Checks if migration is requested by a specific callout cpu. 262 */ 263 static int 264 cc_cce_migrating(struct callout_cpu *cc, int direct) 265 { 266 267 #ifdef SMP 268 return (cc_migration_cpu(cc, direct) != CPUBLOCK); 269 #else 270 return (0); 271 #endif 272 } 273 274 /* 275 * Kernel low level callwheel initialization 276 * called on the BSP during kernel startup. 277 */ 278 static void 279 callout_callwheel_init(void *dummy) 280 { 281 struct callout_cpu *cc; 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 memset(CC_CPU(curcpu), 0, sizeof(cc_cpu)); 290 ncallout = imin(16 + maxproc + maxfiles, 18508); 291 TUNABLE_INT_FETCH("kern.ncallout", &ncallout); 292 293 /* 294 * Calculate callout wheel size, should be next power of two higher 295 * than 'ncallout'. 296 */ 297 callwheelsize = 1 << fls(ncallout); 298 callwheelmask = callwheelsize - 1; 299 300 /* 301 * Fetch whether we're pinning the swi's or not. 302 */ 303 TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi); 304 TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi); 305 306 /* 307 * Only BSP handles timeout(9) and receives a preallocation. 308 * 309 * XXX: Once all timeout(9) consumers are converted this can 310 * be removed. 311 */ 312 timeout_cpu = PCPU_GET(cpuid); 313 cc = CC_CPU(timeout_cpu); 314 cc->cc_callout = malloc(ncallout * sizeof(struct callout), 315 M_CALLOUT, M_WAITOK); 316 callout_cpu_init(cc, timeout_cpu); 317 } 318 SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); 319 320 /* 321 * Initialize the per-cpu callout structures. 322 */ 323 static void 324 callout_cpu_init(struct callout_cpu *cc, int cpu) 325 { 326 struct callout *c; 327 int i; 328 329 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); 330 SLIST_INIT(&cc->cc_callfree); 331 cc->cc_inited = 1; 332 cc->cc_callwheel = malloc_domainset(sizeof(struct callout_list) * 333 callwheelsize, M_CALLOUT, 334 DOMAINSET_PREF(pcpu_find(cpu)->pc_domain), M_WAITOK); 335 for (i = 0; i < callwheelsize; i++) 336 LIST_INIT(&cc->cc_callwheel[i]); 337 TAILQ_INIT(&cc->cc_expireq); 338 cc->cc_firstevent = SBT_MAX; 339 for (i = 0; i < 2; i++) 340 cc_cce_cleanup(cc, i); 341 #ifdef KTR 342 snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name), 343 "callwheel cpu %d", cpu); 344 #endif 345 if (cc->cc_callout == NULL) /* Only BSP handles timeout(9) */ 346 return; 347 for (i = 0; i < ncallout; i++) { 348 c = &cc->cc_callout[i]; 349 callout_init(c, 0); 350 c->c_iflags = CALLOUT_LOCAL_ALLOC; 351 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 352 } 353 } 354 355 #ifdef SMP 356 /* 357 * Switches the cpu tied to a specific callout. 358 * The function expects a locked incoming callout cpu and returns with 359 * locked outcoming callout cpu. 360 */ 361 static struct callout_cpu * 362 callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu) 363 { 364 struct callout_cpu *new_cc; 365 366 MPASS(c != NULL && cc != NULL); 367 CC_LOCK_ASSERT(cc); 368 369 /* 370 * Avoid interrupts and preemption firing after the callout cpu 371 * is blocked in order to avoid deadlocks as the new thread 372 * may be willing to acquire the callout cpu lock. 373 */ 374 c->c_cpu = CPUBLOCK; 375 spinlock_enter(); 376 CC_UNLOCK(cc); 377 new_cc = CC_CPU(new_cpu); 378 CC_LOCK(new_cc); 379 spinlock_exit(); 380 c->c_cpu = new_cpu; 381 return (new_cc); 382 } 383 #endif 384 385 /* 386 * Start standard softclock thread. 387 */ 388 static void 389 start_softclock(void *dummy) 390 { 391 struct callout_cpu *cc; 392 char name[MAXCOMLEN]; 393 #ifdef SMP 394 int cpu; 395 struct intr_event *ie; 396 #endif 397 398 cc = CC_CPU(timeout_cpu); 399 snprintf(name, sizeof(name), "clock (%d)", timeout_cpu); 400 if (swi_add(&clk_intr_event, name, softclock, cc, SWI_CLOCK, 401 INTR_MPSAFE, &cc->cc_cookie)) 402 panic("died while creating standard software ithreads"); 403 if (pin_default_swi && 404 (intr_event_bind(clk_intr_event, timeout_cpu) != 0)) { 405 printf("%s: timeout clock couldn't be pinned to cpu %d\n", 406 __func__, 407 timeout_cpu); 408 } 409 410 #ifdef SMP 411 CPU_FOREACH(cpu) { 412 if (cpu == timeout_cpu) 413 continue; 414 cc = CC_CPU(cpu); 415 cc->cc_callout = NULL; /* Only BSP handles timeout(9). */ 416 callout_cpu_init(cc, cpu); 417 snprintf(name, sizeof(name), "clock (%d)", cpu); 418 ie = NULL; 419 if (swi_add(&ie, name, softclock, cc, SWI_CLOCK, 420 INTR_MPSAFE, &cc->cc_cookie)) 421 panic("died while creating standard software ithreads"); 422 if (pin_pcpu_swi && (intr_event_bind(ie, cpu) != 0)) { 423 printf("%s: per-cpu clock couldn't be pinned to " 424 "cpu %d\n", 425 __func__, 426 cpu); 427 } 428 } 429 #endif 430 } 431 SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); 432 433 #define CC_HASH_SHIFT 8 434 435 static inline u_int 436 callout_hash(sbintime_t sbt) 437 { 438 439 return (sbt >> (32 - CC_HASH_SHIFT)); 440 } 441 442 static inline u_int 443 callout_get_bucket(sbintime_t sbt) 444 { 445 446 return (callout_hash(sbt) & callwheelmask); 447 } 448 449 void 450 callout_process(sbintime_t now) 451 { 452 struct callout *tmp, *tmpn; 453 struct callout_cpu *cc; 454 struct callout_list *sc; 455 sbintime_t first, last, max, tmp_max; 456 uint32_t lookahead; 457 u_int firstb, lastb, nowb; 458 #ifdef CALLOUT_PROFILING 459 int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0; 460 #endif 461 462 cc = CC_SELF(); 463 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET); 464 465 /* Compute the buckets of the last scan and present times. */ 466 firstb = callout_hash(cc->cc_lastscan); 467 cc->cc_lastscan = now; 468 nowb = callout_hash(now); 469 470 /* Compute the last bucket and minimum time of the bucket after it. */ 471 if (nowb == firstb) 472 lookahead = (SBT_1S / 16); 473 else if (nowb - firstb == 1) 474 lookahead = (SBT_1S / 8); 475 else 476 lookahead = (SBT_1S / 2); 477 first = last = now; 478 first += (lookahead / 2); 479 last += lookahead; 480 last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); 481 lastb = callout_hash(last) - 1; 482 max = last; 483 484 /* 485 * Check if we wrapped around the entire wheel from the last scan. 486 * In case, we need to scan entirely the wheel for pending callouts. 487 */ 488 if (lastb - firstb >= callwheelsize) { 489 lastb = firstb + callwheelsize - 1; 490 if (nowb - firstb >= callwheelsize) 491 nowb = lastb; 492 } 493 494 /* Iterate callwheel from firstb to nowb and then up to lastb. */ 495 do { 496 sc = &cc->cc_callwheel[firstb & callwheelmask]; 497 tmp = LIST_FIRST(sc); 498 while (tmp != NULL) { 499 /* Run the callout if present time within allowed. */ 500 if (tmp->c_time <= now) { 501 /* 502 * Consumer told us the callout may be run 503 * directly from hardware interrupt context. 504 */ 505 if (tmp->c_iflags & CALLOUT_DIRECT) { 506 #ifdef CALLOUT_PROFILING 507 ++depth_dir; 508 #endif 509 cc_exec_next(cc) = 510 LIST_NEXT(tmp, c_links.le); 511 cc->cc_bucket = firstb & callwheelmask; 512 LIST_REMOVE(tmp, c_links.le); 513 softclock_call_cc(tmp, cc, 514 #ifdef CALLOUT_PROFILING 515 &mpcalls_dir, &lockcalls_dir, NULL, 516 #endif 517 1); 518 tmp = cc_exec_next(cc); 519 cc_exec_next(cc) = NULL; 520 } else { 521 tmpn = LIST_NEXT(tmp, c_links.le); 522 LIST_REMOVE(tmp, c_links.le); 523 TAILQ_INSERT_TAIL(&cc->cc_expireq, 524 tmp, c_links.tqe); 525 tmp->c_iflags |= CALLOUT_PROCESSED; 526 tmp = tmpn; 527 } 528 continue; 529 } 530 /* Skip events from distant future. */ 531 if (tmp->c_time >= max) 532 goto next; 533 /* 534 * Event minimal time is bigger than present maximal 535 * time, so it cannot be aggregated. 536 */ 537 if (tmp->c_time > last) { 538 lastb = nowb; 539 goto next; 540 } 541 /* Update first and last time, respecting this event. */ 542 if (tmp->c_time < first) 543 first = tmp->c_time; 544 tmp_max = tmp->c_time + tmp->c_precision; 545 if (tmp_max < last) 546 last = tmp_max; 547 next: 548 tmp = LIST_NEXT(tmp, c_links.le); 549 } 550 /* Proceed with the next bucket. */ 551 firstb++; 552 /* 553 * Stop if we looked after present time and found 554 * some event we can't execute at now. 555 * Stop if we looked far enough into the future. 556 */ 557 } while (((int)(firstb - lastb)) <= 0); 558 cc->cc_firstevent = last; 559 #ifndef NO_EVENTTIMERS 560 cpu_new_callout(curcpu, last, first); 561 #endif 562 #ifdef CALLOUT_PROFILING 563 avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8; 564 avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8; 565 avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8; 566 #endif 567 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 568 /* 569 * swi_sched acquires the thread lock, so we don't want to call it 570 * with cc_lock held; incorrect locking order. 571 */ 572 if (!TAILQ_EMPTY(&cc->cc_expireq)) 573 swi_sched(cc->cc_cookie, 0); 574 } 575 576 static struct callout_cpu * 577 callout_lock(struct callout *c) 578 { 579 struct callout_cpu *cc; 580 int cpu; 581 582 for (;;) { 583 cpu = c->c_cpu; 584 #ifdef SMP 585 if (cpu == CPUBLOCK) { 586 while (c->c_cpu == CPUBLOCK) 587 cpu_spinwait(); 588 continue; 589 } 590 #endif 591 cc = CC_CPU(cpu); 592 CC_LOCK(cc); 593 if (cpu == c->c_cpu) 594 break; 595 CC_UNLOCK(cc); 596 } 597 return (cc); 598 } 599 600 static void 601 callout_cc_add(struct callout *c, struct callout_cpu *cc, 602 sbintime_t sbt, sbintime_t precision, void (*func)(void *), 603 void *arg, int cpu, int flags) 604 { 605 int bucket; 606 607 CC_LOCK_ASSERT(cc); 608 if (sbt < cc->cc_lastscan) 609 sbt = cc->cc_lastscan; 610 c->c_arg = arg; 611 c->c_iflags |= CALLOUT_PENDING; 612 c->c_iflags &= ~CALLOUT_PROCESSED; 613 c->c_flags |= CALLOUT_ACTIVE; 614 if (flags & C_DIRECT_EXEC) 615 c->c_iflags |= CALLOUT_DIRECT; 616 c->c_func = func; 617 c->c_time = sbt; 618 c->c_precision = precision; 619 bucket = callout_get_bucket(c->c_time); 620 CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x", 621 c, (int)(c->c_precision >> 32), 622 (u_int)(c->c_precision & 0xffffffff)); 623 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); 624 if (cc->cc_bucket == bucket) 625 cc_exec_next(cc) = c; 626 #ifndef NO_EVENTTIMERS 627 /* 628 * Inform the eventtimers(4) subsystem there's a new callout 629 * that has been inserted, but only if really required. 630 */ 631 if (SBT_MAX - c->c_time < c->c_precision) 632 c->c_precision = SBT_MAX - c->c_time; 633 sbt = c->c_time + c->c_precision; 634 if (sbt < cc->cc_firstevent) { 635 cc->cc_firstevent = sbt; 636 cpu_new_callout(cpu, sbt, c->c_time); 637 } 638 #endif 639 } 640 641 static void 642 callout_cc_del(struct callout *c, struct callout_cpu *cc) 643 { 644 645 if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) == 0) 646 return; 647 c->c_func = NULL; 648 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 649 } 650 651 static void 652 softclock_call_cc(struct callout *c, struct callout_cpu *cc, 653 #ifdef CALLOUT_PROFILING 654 int *mpcalls, int *lockcalls, int *gcalls, 655 #endif 656 int direct) 657 { 658 struct rm_priotracker tracker; 659 void (*c_func)(void *); 660 void *c_arg; 661 struct lock_class *class; 662 struct lock_object *c_lock; 663 uintptr_t lock_status; 664 int c_iflags; 665 #ifdef SMP 666 struct callout_cpu *new_cc; 667 void (*new_func)(void *); 668 void *new_arg; 669 int flags, new_cpu; 670 sbintime_t new_prec, new_time; 671 #endif 672 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 673 sbintime_t sbt1, sbt2; 674 struct timespec ts2; 675 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 676 static timeout_t *lastfunc; 677 #endif 678 679 KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING, 680 ("softclock_call_cc: pend %p %x", c, c->c_iflags)); 681 KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE, 682 ("softclock_call_cc: act %p %x", c, c->c_flags)); 683 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; 684 lock_status = 0; 685 if (c->c_flags & CALLOUT_SHAREDLOCK) { 686 if (class == &lock_class_rm) 687 lock_status = (uintptr_t)&tracker; 688 else 689 lock_status = 1; 690 } 691 c_lock = c->c_lock; 692 c_func = c->c_func; 693 c_arg = c->c_arg; 694 c_iflags = c->c_iflags; 695 if (c->c_iflags & CALLOUT_LOCAL_ALLOC) 696 c->c_iflags = CALLOUT_LOCAL_ALLOC; 697 else 698 c->c_iflags &= ~CALLOUT_PENDING; 699 700 cc_exec_curr(cc, direct) = c; 701 cc_exec_last_func(cc, direct) = c_func; 702 cc_exec_last_arg(cc, direct) = c_arg; 703 cc_exec_cancel(cc, direct) = false; 704 cc_exec_drain(cc, direct) = NULL; 705 CC_UNLOCK(cc); 706 if (c_lock != NULL) { 707 class->lc_lock(c_lock, lock_status); 708 /* 709 * The callout may have been cancelled 710 * while we switched locks. 711 */ 712 if (cc_exec_cancel(cc, direct)) { 713 class->lc_unlock(c_lock); 714 goto skip; 715 } 716 /* The callout cannot be stopped now. */ 717 cc_exec_cancel(cc, direct) = true; 718 if (c_lock == &Giant.lock_object) { 719 #ifdef CALLOUT_PROFILING 720 (*gcalls)++; 721 #endif 722 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", 723 c, c_func, c_arg); 724 } else { 725 #ifdef CALLOUT_PROFILING 726 (*lockcalls)++; 727 #endif 728 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", 729 c, c_func, c_arg); 730 } 731 } else { 732 #ifdef CALLOUT_PROFILING 733 (*mpcalls)++; 734 #endif 735 CTR3(KTR_CALLOUT, "callout %p func %p arg %p", 736 c, c_func, c_arg); 737 } 738 KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running", 739 "func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct); 740 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 741 sbt1 = sbinuptime(); 742 #endif 743 THREAD_NO_SLEEPING(); 744 SDT_PROBE1(callout_execute, , , callout__start, c); 745 c_func(c_arg); 746 SDT_PROBE1(callout_execute, , , callout__end, c); 747 THREAD_SLEEPING_OK(); 748 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 749 sbt2 = sbinuptime(); 750 sbt2 -= sbt1; 751 if (sbt2 > maxdt) { 752 if (lastfunc != c_func || sbt2 > maxdt * 2) { 753 ts2 = sbttots(sbt2); 754 printf( 755 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 756 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); 757 } 758 maxdt = sbt2; 759 lastfunc = c_func; 760 } 761 #endif 762 KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle"); 763 CTR1(KTR_CALLOUT, "callout %p finished", c); 764 if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0) 765 class->lc_unlock(c_lock); 766 skip: 767 CC_LOCK(cc); 768 KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr")); 769 cc_exec_curr(cc, direct) = NULL; 770 if (cc_exec_drain(cc, direct)) { 771 void (*drain)(void *); 772 773 drain = cc_exec_drain(cc, direct); 774 cc_exec_drain(cc, direct) = NULL; 775 CC_UNLOCK(cc); 776 drain(c_arg); 777 CC_LOCK(cc); 778 } 779 if (cc_exec_waiting(cc, direct)) { 780 /* 781 * There is someone waiting for the 782 * callout to complete. 783 * If the callout was scheduled for 784 * migration just cancel it. 785 */ 786 if (cc_cce_migrating(cc, direct)) { 787 cc_cce_cleanup(cc, direct); 788 789 /* 790 * It should be assert here that the callout is not 791 * destroyed but that is not easy. 792 */ 793 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 794 } 795 cc_exec_waiting(cc, direct) = false; 796 CC_UNLOCK(cc); 797 wakeup(&cc_exec_waiting(cc, direct)); 798 CC_LOCK(cc); 799 } else if (cc_cce_migrating(cc, direct)) { 800 KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0, 801 ("Migrating legacy callout %p", c)); 802 #ifdef SMP 803 /* 804 * If the callout was scheduled for 805 * migration just perform it now. 806 */ 807 new_cpu = cc_migration_cpu(cc, direct); 808 new_time = cc_migration_time(cc, direct); 809 new_prec = cc_migration_prec(cc, direct); 810 new_func = cc_migration_func(cc, direct); 811 new_arg = cc_migration_arg(cc, direct); 812 cc_cce_cleanup(cc, direct); 813 814 /* 815 * It should be assert here that the callout is not destroyed 816 * but that is not easy. 817 * 818 * As first thing, handle deferred callout stops. 819 */ 820 if (!callout_migrating(c)) { 821 CTR3(KTR_CALLOUT, 822 "deferred cancelled %p func %p arg %p", 823 c, new_func, new_arg); 824 callout_cc_del(c, cc); 825 return; 826 } 827 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 828 829 new_cc = callout_cpu_switch(c, cc, new_cpu); 830 flags = (direct) ? C_DIRECT_EXEC : 0; 831 callout_cc_add(c, new_cc, new_time, new_prec, new_func, 832 new_arg, new_cpu, flags); 833 CC_UNLOCK(new_cc); 834 CC_LOCK(cc); 835 #else 836 panic("migration should not happen"); 837 #endif 838 } 839 /* 840 * If the current callout is locally allocated (from 841 * timeout(9)) then put it on the freelist. 842 * 843 * Note: we need to check the cached copy of c_iflags because 844 * if it was not local, then it's not safe to deref the 845 * callout pointer. 846 */ 847 KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0 || 848 c->c_iflags == CALLOUT_LOCAL_ALLOC, 849 ("corrupted callout")); 850 if (c_iflags & CALLOUT_LOCAL_ALLOC) 851 callout_cc_del(c, cc); 852 } 853 854 /* 855 * The callout mechanism is based on the work of Adam M. Costello and 856 * George Varghese, published in a technical report entitled "Redesigning 857 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 858 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 859 * used in this implementation was published by G. Varghese and T. Lauck in 860 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 861 * the Efficient Implementation of a Timer Facility" in the Proceedings of 862 * the 11th ACM Annual Symposium on Operating Systems Principles, 863 * Austin, Texas Nov 1987. 864 */ 865 866 /* 867 * Software (low priority) clock interrupt. 868 * Run periodic events from timeout queue. 869 */ 870 void 871 softclock(void *arg) 872 { 873 struct callout_cpu *cc; 874 struct callout *c; 875 #ifdef CALLOUT_PROFILING 876 int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0; 877 #endif 878 879 cc = (struct callout_cpu *)arg; 880 CC_LOCK(cc); 881 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { 882 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 883 softclock_call_cc(c, cc, 884 #ifdef CALLOUT_PROFILING 885 &mpcalls, &lockcalls, &gcalls, 886 #endif 887 0); 888 #ifdef CALLOUT_PROFILING 889 ++depth; 890 #endif 891 } 892 #ifdef CALLOUT_PROFILING 893 avg_depth += (depth * 1000 - avg_depth) >> 8; 894 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 895 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 896 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 897 #endif 898 CC_UNLOCK(cc); 899 } 900 901 /* 902 * timeout -- 903 * Execute a function after a specified length of time. 904 * 905 * untimeout -- 906 * Cancel previous timeout function call. 907 * 908 * callout_handle_init -- 909 * Initialize a handle so that using it with untimeout is benign. 910 * 911 * See AT&T BCI Driver Reference Manual for specification. This 912 * implementation differs from that one in that although an 913 * identification value is returned from timeout, the original 914 * arguments to timeout as well as the identifier are used to 915 * identify entries for untimeout. 916 */ 917 struct callout_handle 918 timeout(timeout_t *ftn, void *arg, int to_ticks) 919 { 920 struct callout_cpu *cc; 921 struct callout *new; 922 struct callout_handle handle; 923 924 cc = CC_CPU(timeout_cpu); 925 CC_LOCK(cc); 926 /* Fill in the next free callout structure. */ 927 new = SLIST_FIRST(&cc->cc_callfree); 928 if (new == NULL) 929 /* XXX Attempt to malloc first */ 930 panic("timeout table full"); 931 SLIST_REMOVE_HEAD(&cc->cc_callfree, c_links.sle); 932 callout_reset(new, to_ticks, ftn, arg); 933 handle.callout = new; 934 CC_UNLOCK(cc); 935 936 return (handle); 937 } 938 939 void 940 untimeout(timeout_t *ftn, void *arg, struct callout_handle handle) 941 { 942 struct callout_cpu *cc; 943 944 /* 945 * Check for a handle that was initialized 946 * by callout_handle_init, but never used 947 * for a real timeout. 948 */ 949 if (handle.callout == NULL) 950 return; 951 952 cc = callout_lock(handle.callout); 953 if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) 954 callout_stop(handle.callout); 955 CC_UNLOCK(cc); 956 } 957 958 void 959 callout_handle_init(struct callout_handle *handle) 960 { 961 handle->callout = NULL; 962 } 963 964 void 965 callout_when(sbintime_t sbt, sbintime_t precision, int flags, 966 sbintime_t *res, sbintime_t *prec_res) 967 { 968 sbintime_t to_sbt, to_pr; 969 970 if ((flags & (C_ABSOLUTE | C_PRECALC)) != 0) { 971 *res = sbt; 972 *prec_res = precision; 973 return; 974 } 975 if ((flags & C_HARDCLOCK) != 0 && sbt < tick_sbt) 976 sbt = tick_sbt; 977 if ((flags & C_HARDCLOCK) != 0 || 978 #ifdef NO_EVENTTIMERS 979 sbt >= sbt_timethreshold) { 980 to_sbt = getsbinuptime(); 981 982 /* Add safety belt for the case of hz > 1000. */ 983 to_sbt += tc_tick_sbt - tick_sbt; 984 #else 985 sbt >= sbt_tickthreshold) { 986 /* 987 * Obtain the time of the last hardclock() call on 988 * this CPU directly from the kern_clocksource.c. 989 * This value is per-CPU, but it is equal for all 990 * active ones. 991 */ 992 #ifdef __LP64__ 993 to_sbt = DPCPU_GET(hardclocktime); 994 #else 995 spinlock_enter(); 996 to_sbt = DPCPU_GET(hardclocktime); 997 spinlock_exit(); 998 #endif 999 #endif 1000 if (cold && to_sbt == 0) 1001 to_sbt = sbinuptime(); 1002 if ((flags & C_HARDCLOCK) == 0) 1003 to_sbt += tick_sbt; 1004 } else 1005 to_sbt = sbinuptime(); 1006 if (SBT_MAX - to_sbt < sbt) 1007 to_sbt = SBT_MAX; 1008 else 1009 to_sbt += sbt; 1010 *res = to_sbt; 1011 to_pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : 1012 sbt >> C_PRELGET(flags)); 1013 *prec_res = to_pr > precision ? to_pr : precision; 1014 } 1015 1016 /* 1017 * New interface; clients allocate their own callout structures. 1018 * 1019 * callout_reset() - establish or change a timeout 1020 * callout_stop() - disestablish a timeout 1021 * callout_init() - initialize a callout structure so that it can 1022 * safely be passed to callout_reset() and callout_stop() 1023 * 1024 * <sys/callout.h> defines three convenience macros: 1025 * 1026 * callout_active() - returns truth if callout has not been stopped, 1027 * drained, or deactivated since the last time the callout was 1028 * reset. 1029 * callout_pending() - returns truth if callout is still waiting for timeout 1030 * callout_deactivate() - marks the callout as having been serviced 1031 */ 1032 int 1033 callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t prec, 1034 void (*ftn)(void *), void *arg, int cpu, int flags) 1035 { 1036 sbintime_t to_sbt, precision; 1037 struct callout_cpu *cc; 1038 int cancelled, direct; 1039 int ignore_cpu=0; 1040 1041 cancelled = 0; 1042 if (cpu == -1) { 1043 ignore_cpu = 1; 1044 } else if ((cpu >= MAXCPU) || 1045 ((CC_CPU(cpu))->cc_inited == 0)) { 1046 /* Invalid CPU spec */ 1047 panic("Invalid CPU in callout %d", cpu); 1048 } 1049 callout_when(sbt, prec, flags, &to_sbt, &precision); 1050 1051 /* 1052 * This flag used to be added by callout_cc_add, but the 1053 * first time you call this we could end up with the 1054 * wrong direct flag if we don't do it before we add. 1055 */ 1056 if (flags & C_DIRECT_EXEC) { 1057 direct = 1; 1058 } else { 1059 direct = 0; 1060 } 1061 KASSERT(!direct || c->c_lock == NULL, 1062 ("%s: direct callout %p has lock", __func__, c)); 1063 cc = callout_lock(c); 1064 /* 1065 * Don't allow migration of pre-allocated callouts lest they 1066 * become unbalanced or handle the case where the user does 1067 * not care. 1068 */ 1069 if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) || 1070 ignore_cpu) { 1071 cpu = c->c_cpu; 1072 } 1073 1074 if (cc_exec_curr(cc, direct) == c) { 1075 /* 1076 * We're being asked to reschedule a callout which is 1077 * currently in progress. If there is a lock then we 1078 * can cancel the callout if it has not really started. 1079 */ 1080 if (c->c_lock != NULL && !cc_exec_cancel(cc, direct)) 1081 cancelled = cc_exec_cancel(cc, direct) = true; 1082 if (cc_exec_waiting(cc, direct) || cc_exec_drain(cc, direct)) { 1083 /* 1084 * Someone has called callout_drain to kill this 1085 * callout. Don't reschedule. 1086 */ 1087 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 1088 cancelled ? "cancelled" : "failed to cancel", 1089 c, c->c_func, c->c_arg); 1090 CC_UNLOCK(cc); 1091 return (cancelled); 1092 } 1093 #ifdef SMP 1094 if (callout_migrating(c)) { 1095 /* 1096 * This only occurs when a second callout_reset_sbt_on 1097 * is made after a previous one moved it into 1098 * deferred migration (below). Note we do *not* change 1099 * the prev_cpu even though the previous target may 1100 * be different. 1101 */ 1102 cc_migration_cpu(cc, direct) = cpu; 1103 cc_migration_time(cc, direct) = to_sbt; 1104 cc_migration_prec(cc, direct) = precision; 1105 cc_migration_func(cc, direct) = ftn; 1106 cc_migration_arg(cc, direct) = arg; 1107 cancelled = 1; 1108 CC_UNLOCK(cc); 1109 return (cancelled); 1110 } 1111 #endif 1112 } 1113 if (c->c_iflags & CALLOUT_PENDING) { 1114 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1115 if (cc_exec_next(cc) == c) 1116 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1117 LIST_REMOVE(c, c_links.le); 1118 } else { 1119 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1120 } 1121 cancelled = 1; 1122 c->c_iflags &= ~ CALLOUT_PENDING; 1123 c->c_flags &= ~ CALLOUT_ACTIVE; 1124 } 1125 1126 #ifdef SMP 1127 /* 1128 * If the callout must migrate try to perform it immediately. 1129 * If the callout is currently running, just defer the migration 1130 * to a more appropriate moment. 1131 */ 1132 if (c->c_cpu != cpu) { 1133 if (cc_exec_curr(cc, direct) == c) { 1134 /* 1135 * Pending will have been removed since we are 1136 * actually executing the callout on another 1137 * CPU. That callout should be waiting on the 1138 * lock the caller holds. If we set both 1139 * active/and/pending after we return and the 1140 * lock on the executing callout proceeds, it 1141 * will then see pending is true and return. 1142 * At the return from the actual callout execution 1143 * the migration will occur in softclock_call_cc 1144 * and this new callout will be placed on the 1145 * new CPU via a call to callout_cpu_switch() which 1146 * will get the lock on the right CPU followed 1147 * by a call callout_cc_add() which will add it there. 1148 * (see above in softclock_call_cc()). 1149 */ 1150 cc_migration_cpu(cc, direct) = cpu; 1151 cc_migration_time(cc, direct) = to_sbt; 1152 cc_migration_prec(cc, direct) = precision; 1153 cc_migration_func(cc, direct) = ftn; 1154 cc_migration_arg(cc, direct) = arg; 1155 c->c_iflags |= (CALLOUT_DFRMIGRATION | CALLOUT_PENDING); 1156 c->c_flags |= CALLOUT_ACTIVE; 1157 CTR6(KTR_CALLOUT, 1158 "migration of %p func %p arg %p in %d.%08x to %u deferred", 1159 c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1160 (u_int)(to_sbt & 0xffffffff), cpu); 1161 CC_UNLOCK(cc); 1162 return (cancelled); 1163 } 1164 cc = callout_cpu_switch(c, cc, cpu); 1165 } 1166 #endif 1167 1168 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags); 1169 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", 1170 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1171 (u_int)(to_sbt & 0xffffffff)); 1172 CC_UNLOCK(cc); 1173 1174 return (cancelled); 1175 } 1176 1177 /* 1178 * Common idioms that can be optimized in the future. 1179 */ 1180 int 1181 callout_schedule_on(struct callout *c, int to_ticks, int cpu) 1182 { 1183 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 1184 } 1185 1186 int 1187 callout_schedule(struct callout *c, int to_ticks) 1188 { 1189 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 1190 } 1191 1192 int 1193 _callout_stop_safe(struct callout *c, int flags, void (*drain)(void *)) 1194 { 1195 struct callout_cpu *cc, *old_cc; 1196 struct lock_class *class; 1197 int direct, sq_locked, use_lock; 1198 int cancelled, not_on_a_list; 1199 1200 if ((flags & CS_DRAIN) != 0) 1201 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock, 1202 "calling %s", __func__); 1203 1204 /* 1205 * Some old subsystems don't hold Giant while running a callout_stop(), 1206 * so just discard this check for the moment. 1207 */ 1208 if ((flags & CS_DRAIN) == 0 && c->c_lock != NULL) { 1209 if (c->c_lock == &Giant.lock_object) 1210 use_lock = mtx_owned(&Giant); 1211 else { 1212 use_lock = 1; 1213 class = LOCK_CLASS(c->c_lock); 1214 class->lc_assert(c->c_lock, LA_XLOCKED); 1215 } 1216 } else 1217 use_lock = 0; 1218 if (c->c_iflags & CALLOUT_DIRECT) { 1219 direct = 1; 1220 } else { 1221 direct = 0; 1222 } 1223 sq_locked = 0; 1224 old_cc = NULL; 1225 again: 1226 cc = callout_lock(c); 1227 1228 if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) == 1229 (CALLOUT_DFRMIGRATION | CALLOUT_PENDING) && 1230 ((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) { 1231 /* 1232 * Special case where this slipped in while we 1233 * were migrating *as* the callout is about to 1234 * execute. The caller probably holds the lock 1235 * the callout wants. 1236 * 1237 * Get rid of the migration first. Then set 1238 * the flag that tells this code *not* to 1239 * try to remove it from any lists (its not 1240 * on one yet). When the callout wheel runs, 1241 * it will ignore this callout. 1242 */ 1243 c->c_iflags &= ~CALLOUT_PENDING; 1244 c->c_flags &= ~CALLOUT_ACTIVE; 1245 not_on_a_list = 1; 1246 } else { 1247 not_on_a_list = 0; 1248 } 1249 1250 /* 1251 * If the callout was migrating while the callout cpu lock was 1252 * dropped, just drop the sleepqueue lock and check the states 1253 * again. 1254 */ 1255 if (sq_locked != 0 && cc != old_cc) { 1256 #ifdef SMP 1257 CC_UNLOCK(cc); 1258 sleepq_release(&cc_exec_waiting(old_cc, direct)); 1259 sq_locked = 0; 1260 old_cc = NULL; 1261 goto again; 1262 #else 1263 panic("migration should not happen"); 1264 #endif 1265 } 1266 1267 /* 1268 * If the callout is running, try to stop it or drain it. 1269 */ 1270 if (cc_exec_curr(cc, direct) == c) { 1271 /* 1272 * Succeed we to stop it or not, we must clear the 1273 * active flag - this is what API users expect. If we're 1274 * draining and the callout is currently executing, first wait 1275 * until it finishes. 1276 */ 1277 if ((flags & CS_DRAIN) == 0) 1278 c->c_flags &= ~CALLOUT_ACTIVE; 1279 1280 if ((flags & CS_DRAIN) != 0) { 1281 /* 1282 * The current callout is running (or just 1283 * about to run) and blocking is allowed, so 1284 * just wait for the current invocation to 1285 * finish. 1286 */ 1287 while (cc_exec_curr(cc, direct) == c) { 1288 /* 1289 * Use direct calls to sleepqueue interface 1290 * instead of cv/msleep in order to avoid 1291 * a LOR between cc_lock and sleepqueue 1292 * chain spinlocks. This piece of code 1293 * emulates a msleep_spin() call actually. 1294 * 1295 * If we already have the sleepqueue chain 1296 * locked, then we can safely block. If we 1297 * don't already have it locked, however, 1298 * we have to drop the cc_lock to lock 1299 * it. This opens several races, so we 1300 * restart at the beginning once we have 1301 * both locks. If nothing has changed, then 1302 * we will end up back here with sq_locked 1303 * set. 1304 */ 1305 if (!sq_locked) { 1306 CC_UNLOCK(cc); 1307 sleepq_lock( 1308 &cc_exec_waiting(cc, direct)); 1309 sq_locked = 1; 1310 old_cc = cc; 1311 goto again; 1312 } 1313 1314 /* 1315 * Migration could be cancelled here, but 1316 * as long as it is still not sure when it 1317 * will be packed up, just let softclock() 1318 * take care of it. 1319 */ 1320 cc_exec_waiting(cc, direct) = true; 1321 DROP_GIANT(); 1322 CC_UNLOCK(cc); 1323 sleepq_add( 1324 &cc_exec_waiting(cc, direct), 1325 &cc->cc_lock.lock_object, "codrain", 1326 SLEEPQ_SLEEP, 0); 1327 sleepq_wait( 1328 &cc_exec_waiting(cc, direct), 1329 0); 1330 sq_locked = 0; 1331 old_cc = NULL; 1332 1333 /* Reacquire locks previously released. */ 1334 PICKUP_GIANT(); 1335 CC_LOCK(cc); 1336 } 1337 c->c_flags &= ~CALLOUT_ACTIVE; 1338 } else if (use_lock && 1339 !cc_exec_cancel(cc, direct) && (drain == NULL)) { 1340 1341 /* 1342 * The current callout is waiting for its 1343 * lock which we hold. Cancel the callout 1344 * and return. After our caller drops the 1345 * lock, the callout will be skipped in 1346 * softclock(). This *only* works with a 1347 * callout_stop() *not* callout_drain() or 1348 * callout_async_drain(). 1349 */ 1350 cc_exec_cancel(cc, direct) = true; 1351 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1352 c, c->c_func, c->c_arg); 1353 KASSERT(!cc_cce_migrating(cc, direct), 1354 ("callout wrongly scheduled for migration")); 1355 if (callout_migrating(c)) { 1356 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1357 #ifdef SMP 1358 cc_migration_cpu(cc, direct) = CPUBLOCK; 1359 cc_migration_time(cc, direct) = 0; 1360 cc_migration_prec(cc, direct) = 0; 1361 cc_migration_func(cc, direct) = NULL; 1362 cc_migration_arg(cc, direct) = NULL; 1363 #endif 1364 } 1365 CC_UNLOCK(cc); 1366 KASSERT(!sq_locked, ("sleepqueue chain locked")); 1367 return (1); 1368 } else if (callout_migrating(c)) { 1369 /* 1370 * The callout is currently being serviced 1371 * and the "next" callout is scheduled at 1372 * its completion with a migration. We remove 1373 * the migration flag so it *won't* get rescheduled, 1374 * but we can't stop the one thats running so 1375 * we return 0. 1376 */ 1377 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1378 #ifdef SMP 1379 /* 1380 * We can't call cc_cce_cleanup here since 1381 * if we do it will remove .ce_curr and 1382 * its still running. This will prevent a 1383 * reschedule of the callout when the 1384 * execution completes. 1385 */ 1386 cc_migration_cpu(cc, direct) = CPUBLOCK; 1387 cc_migration_time(cc, direct) = 0; 1388 cc_migration_prec(cc, direct) = 0; 1389 cc_migration_func(cc, direct) = NULL; 1390 cc_migration_arg(cc, direct) = NULL; 1391 #endif 1392 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 1393 c, c->c_func, c->c_arg); 1394 if (drain) { 1395 cc_exec_drain(cc, direct) = drain; 1396 } 1397 CC_UNLOCK(cc); 1398 return ((flags & CS_EXECUTING) != 0); 1399 } 1400 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1401 c, c->c_func, c->c_arg); 1402 if (drain) { 1403 cc_exec_drain(cc, direct) = drain; 1404 } 1405 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 1406 cancelled = ((flags & CS_EXECUTING) != 0); 1407 } else 1408 cancelled = 1; 1409 1410 if (sq_locked) 1411 sleepq_release(&cc_exec_waiting(cc, direct)); 1412 1413 if ((c->c_iflags & CALLOUT_PENDING) == 0) { 1414 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1415 c, c->c_func, c->c_arg); 1416 /* 1417 * For not scheduled and not executing callout return 1418 * negative value. 1419 */ 1420 if (cc_exec_curr(cc, direct) != c) 1421 cancelled = -1; 1422 CC_UNLOCK(cc); 1423 return (cancelled); 1424 } 1425 1426 c->c_iflags &= ~CALLOUT_PENDING; 1427 c->c_flags &= ~CALLOUT_ACTIVE; 1428 1429 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1430 c, c->c_func, c->c_arg); 1431 if (not_on_a_list == 0) { 1432 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1433 if (cc_exec_next(cc) == c) 1434 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1435 LIST_REMOVE(c, c_links.le); 1436 } else { 1437 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1438 } 1439 } 1440 callout_cc_del(c, cc); 1441 CC_UNLOCK(cc); 1442 return (cancelled); 1443 } 1444 1445 void 1446 callout_init(struct callout *c, int mpsafe) 1447 { 1448 bzero(c, sizeof *c); 1449 if (mpsafe) { 1450 c->c_lock = NULL; 1451 c->c_iflags = CALLOUT_RETURNUNLOCKED; 1452 } else { 1453 c->c_lock = &Giant.lock_object; 1454 c->c_iflags = 0; 1455 } 1456 c->c_cpu = timeout_cpu; 1457 } 1458 1459 void 1460 _callout_init_lock(struct callout *c, struct lock_object *lock, int flags) 1461 { 1462 bzero(c, sizeof *c); 1463 c->c_lock = lock; 1464 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1465 ("callout_init_lock: bad flags %d", flags)); 1466 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1467 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1468 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & 1469 (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class", 1470 __func__)); 1471 c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1472 c->c_cpu = timeout_cpu; 1473 } 1474 1475 #ifdef APM_FIXUP_CALLTODO 1476 /* 1477 * Adjust the kernel calltodo timeout list. This routine is used after 1478 * an APM resume to recalculate the calltodo timer list values with the 1479 * number of hz's we have been sleeping. The next hardclock() will detect 1480 * that there are fired timers and run softclock() to execute them. 1481 * 1482 * Please note, I have not done an exhaustive analysis of what code this 1483 * might break. I am motivated to have my select()'s and alarm()'s that 1484 * have expired during suspend firing upon resume so that the applications 1485 * which set the timer can do the maintanence the timer was for as close 1486 * as possible to the originally intended time. Testing this code for a 1487 * week showed that resuming from a suspend resulted in 22 to 25 timers 1488 * firing, which seemed independent on whether the suspend was 2 hours or 1489 * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu> 1490 */ 1491 void 1492 adjust_timeout_calltodo(struct timeval *time_change) 1493 { 1494 struct callout *p; 1495 unsigned long delta_ticks; 1496 1497 /* 1498 * How many ticks were we asleep? 1499 * (stolen from tvtohz()). 1500 */ 1501 1502 /* Don't do anything */ 1503 if (time_change->tv_sec < 0) 1504 return; 1505 else if (time_change->tv_sec <= LONG_MAX / 1000000) 1506 delta_ticks = howmany(time_change->tv_sec * 1000000 + 1507 time_change->tv_usec, tick) + 1; 1508 else if (time_change->tv_sec <= LONG_MAX / hz) 1509 delta_ticks = time_change->tv_sec * hz + 1510 howmany(time_change->tv_usec, tick) + 1; 1511 else 1512 delta_ticks = LONG_MAX; 1513 1514 if (delta_ticks > INT_MAX) 1515 delta_ticks = INT_MAX; 1516 1517 /* 1518 * Now rip through the timer calltodo list looking for timers 1519 * to expire. 1520 */ 1521 1522 /* don't collide with softclock() */ 1523 CC_LOCK(cc); 1524 for (p = calltodo.c_next; p != NULL; p = p->c_next) { 1525 p->c_time -= delta_ticks; 1526 1527 /* Break if the timer had more time on it than delta_ticks */ 1528 if (p->c_time > 0) 1529 break; 1530 1531 /* take back the ticks the timer didn't use (p->c_time <= 0) */ 1532 delta_ticks = -p->c_time; 1533 } 1534 CC_UNLOCK(cc); 1535 1536 return; 1537 } 1538 #endif /* APM_FIXUP_CALLTODO */ 1539 1540 static int 1541 flssbt(sbintime_t sbt) 1542 { 1543 1544 sbt += (uint64_t)sbt >> 1; 1545 if (sizeof(long) >= sizeof(sbintime_t)) 1546 return (flsl(sbt)); 1547 if (sbt >= SBT_1S) 1548 return (flsl(((uint64_t)sbt) >> 32) + 32); 1549 return (flsl(sbt)); 1550 } 1551 1552 /* 1553 * Dump immediate statistic snapshot of the scheduled callouts. 1554 */ 1555 static int 1556 sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1557 { 1558 struct callout *tmp; 1559 struct callout_cpu *cc; 1560 struct callout_list *sc; 1561 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; 1562 int ct[64], cpr[64], ccpbk[32]; 1563 int error, val, i, count, tcum, pcum, maxc, c, medc; 1564 #ifdef SMP 1565 int cpu; 1566 #endif 1567 1568 val = 0; 1569 error = sysctl_handle_int(oidp, &val, 0, req); 1570 if (error != 0 || req->newptr == NULL) 1571 return (error); 1572 count = maxc = 0; 1573 st = spr = maxt = maxpr = 0; 1574 bzero(ccpbk, sizeof(ccpbk)); 1575 bzero(ct, sizeof(ct)); 1576 bzero(cpr, sizeof(cpr)); 1577 now = sbinuptime(); 1578 #ifdef SMP 1579 CPU_FOREACH(cpu) { 1580 cc = CC_CPU(cpu); 1581 #else 1582 cc = CC_CPU(timeout_cpu); 1583 #endif 1584 CC_LOCK(cc); 1585 for (i = 0; i < callwheelsize; i++) { 1586 sc = &cc->cc_callwheel[i]; 1587 c = 0; 1588 LIST_FOREACH(tmp, sc, c_links.le) { 1589 c++; 1590 t = tmp->c_time - now; 1591 if (t < 0) 1592 t = 0; 1593 st += t / SBT_1US; 1594 spr += tmp->c_precision / SBT_1US; 1595 if (t > maxt) 1596 maxt = t; 1597 if (tmp->c_precision > maxpr) 1598 maxpr = tmp->c_precision; 1599 ct[flssbt(t)]++; 1600 cpr[flssbt(tmp->c_precision)]++; 1601 } 1602 if (c > maxc) 1603 maxc = c; 1604 ccpbk[fls(c + c / 2)]++; 1605 count += c; 1606 } 1607 CC_UNLOCK(cc); 1608 #ifdef SMP 1609 } 1610 #endif 1611 1612 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1613 tcum += ct[i]; 1614 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1615 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) 1616 pcum += cpr[i]; 1617 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1618 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1619 c += ccpbk[i]; 1620 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1621 1622 printf("Scheduled callouts statistic snapshot:\n"); 1623 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1624 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1625 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1626 medc, 1627 count / callwheelsize / mp_ncpus, 1628 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1629 maxc); 1630 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1631 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1632 (st / count) / 1000000, (st / count) % 1000000, 1633 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); 1634 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1635 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, 1636 (spr / count) / 1000000, (spr / count) % 1000000, 1637 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); 1638 printf(" Distribution: \tbuckets\t time\t tcum\t" 1639 " prec\t pcum\n"); 1640 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1641 if (ct[i] == 0 && cpr[i] == 0) 1642 continue; 1643 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1644 tcum += ct[i]; 1645 pcum += cpr[i]; 1646 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", 1647 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1648 i - 1 - (32 - CC_HASH_SHIFT), 1649 ct[i], tcum, cpr[i], pcum); 1650 } 1651 return (error); 1652 } 1653 SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1654 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1655 0, 0, sysctl_kern_callout_stat, "I", 1656 "Dump immediate statistic snapshot of the scheduled callouts"); 1657 1658 #ifdef DDB 1659 static void 1660 _show_callout(struct callout *c) 1661 { 1662 1663 db_printf("callout %p\n", c); 1664 #define C_DB_PRINTF(f, e) db_printf(" %s = " f "\n", #e, c->e); 1665 db_printf(" &c_links = %p\n", &(c->c_links)); 1666 C_DB_PRINTF("%" PRId64, c_time); 1667 C_DB_PRINTF("%" PRId64, c_precision); 1668 C_DB_PRINTF("%p", c_arg); 1669 C_DB_PRINTF("%p", c_func); 1670 C_DB_PRINTF("%p", c_lock); 1671 C_DB_PRINTF("%#x", c_flags); 1672 C_DB_PRINTF("%#x", c_iflags); 1673 C_DB_PRINTF("%d", c_cpu); 1674 #undef C_DB_PRINTF 1675 } 1676 1677 DB_SHOW_COMMAND(callout, db_show_callout) 1678 { 1679 1680 if (!have_addr) { 1681 db_printf("usage: show callout <struct callout *>\n"); 1682 return; 1683 } 1684 1685 _show_callout((struct callout *)addr); 1686 } 1687 1688 static void 1689 _show_last_callout(int cpu, int direct, const char *dirstr) 1690 { 1691 struct callout_cpu *cc; 1692 void *func, *arg; 1693 1694 cc = CC_CPU(cpu); 1695 func = cc_exec_last_func(cc, direct); 1696 arg = cc_exec_last_arg(cc, direct); 1697 db_printf("cpu %d last%s callout function: %p ", cpu, dirstr, func); 1698 db_printsym((db_expr_t)func, DB_STGY_ANY); 1699 db_printf("\ncpu %d last%s callout argument: %p\n", cpu, dirstr, arg); 1700 } 1701 1702 DB_SHOW_COMMAND(callout_last, db_show_callout_last) 1703 { 1704 int cpu, last; 1705 1706 if (have_addr) { 1707 if (addr < 0 || addr > mp_maxid || CPU_ABSENT(addr)) { 1708 db_printf("no such cpu: %d\n", (int)addr); 1709 return; 1710 } 1711 cpu = last = addr; 1712 } else { 1713 cpu = 0; 1714 last = mp_maxid; 1715 } 1716 1717 while (cpu <= last) { 1718 if (!CPU_ABSENT(cpu)) { 1719 _show_last_callout(cpu, 0, ""); 1720 _show_last_callout(cpu, 1, " direct"); 1721 } 1722 cpu++; 1723 } 1724 } 1725 #endif /* DDB */ 1726