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 callout_func_t *cc_drain; 149 void *cc_last_func; 150 void *cc_last_arg; 151 #ifdef SMP 152 callout_func_t *ce_migration_func; 153 void *ce_migration_arg; 154 sbintime_t ce_migration_time; 155 sbintime_t ce_migration_prec; 156 int ce_migration_cpu; 157 #endif 158 bool cc_cancel; 159 bool cc_waiting; 160 }; 161 162 /* 163 * There is one struct callout_cpu per cpu, holding all relevant 164 * state for the callout processing thread on the individual CPU. 165 */ 166 struct callout_cpu { 167 struct mtx_padalign cc_lock; 168 struct cc_exec cc_exec_entity[2]; 169 struct callout *cc_next; 170 struct callout *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 callout_func_t *c_func, *drain; 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 callout_func_t *new_func; 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 callout_func_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 drain = cc_exec_drain(cc, direct); 772 cc_exec_drain(cc, direct) = NULL; 773 CC_UNLOCK(cc); 774 drain(c_arg); 775 CC_LOCK(cc); 776 } 777 if (cc_exec_waiting(cc, direct)) { 778 /* 779 * There is someone waiting for the 780 * callout to complete. 781 * If the callout was scheduled for 782 * migration just cancel it. 783 */ 784 if (cc_cce_migrating(cc, direct)) { 785 cc_cce_cleanup(cc, direct); 786 787 /* 788 * It should be assert here that the callout is not 789 * destroyed but that is not easy. 790 */ 791 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 792 } 793 cc_exec_waiting(cc, direct) = false; 794 CC_UNLOCK(cc); 795 wakeup(&cc_exec_waiting(cc, direct)); 796 CC_LOCK(cc); 797 } else if (cc_cce_migrating(cc, direct)) { 798 KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0, 799 ("Migrating legacy callout %p", c)); 800 #ifdef SMP 801 /* 802 * If the callout was scheduled for 803 * migration just perform it now. 804 */ 805 new_cpu = cc_migration_cpu(cc, direct); 806 new_time = cc_migration_time(cc, direct); 807 new_prec = cc_migration_prec(cc, direct); 808 new_func = cc_migration_func(cc, direct); 809 new_arg = cc_migration_arg(cc, direct); 810 cc_cce_cleanup(cc, direct); 811 812 /* 813 * It should be assert here that the callout is not destroyed 814 * but that is not easy. 815 * 816 * As first thing, handle deferred callout stops. 817 */ 818 if (!callout_migrating(c)) { 819 CTR3(KTR_CALLOUT, 820 "deferred cancelled %p func %p arg %p", 821 c, new_func, new_arg); 822 callout_cc_del(c, cc); 823 return; 824 } 825 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 826 827 new_cc = callout_cpu_switch(c, cc, new_cpu); 828 flags = (direct) ? C_DIRECT_EXEC : 0; 829 callout_cc_add(c, new_cc, new_time, new_prec, new_func, 830 new_arg, new_cpu, flags); 831 CC_UNLOCK(new_cc); 832 CC_LOCK(cc); 833 #else 834 panic("migration should not happen"); 835 #endif 836 } 837 /* 838 * If the current callout is locally allocated (from 839 * timeout(9)) then put it on the freelist. 840 * 841 * Note: we need to check the cached copy of c_iflags because 842 * if it was not local, then it's not safe to deref the 843 * callout pointer. 844 */ 845 KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0 || 846 c->c_iflags == CALLOUT_LOCAL_ALLOC, 847 ("corrupted callout")); 848 if (c_iflags & CALLOUT_LOCAL_ALLOC) 849 callout_cc_del(c, cc); 850 } 851 852 /* 853 * The callout mechanism is based on the work of Adam M. Costello and 854 * George Varghese, published in a technical report entitled "Redesigning 855 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 856 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 857 * used in this implementation was published by G. Varghese and T. Lauck in 858 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 859 * the Efficient Implementation of a Timer Facility" in the Proceedings of 860 * the 11th ACM Annual Symposium on Operating Systems Principles, 861 * Austin, Texas Nov 1987. 862 */ 863 864 /* 865 * Software (low priority) clock interrupt. 866 * Run periodic events from timeout queue. 867 */ 868 void 869 softclock(void *arg) 870 { 871 struct callout_cpu *cc; 872 struct callout *c; 873 #ifdef CALLOUT_PROFILING 874 int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0; 875 #endif 876 877 cc = (struct callout_cpu *)arg; 878 CC_LOCK(cc); 879 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { 880 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 881 softclock_call_cc(c, cc, 882 #ifdef CALLOUT_PROFILING 883 &mpcalls, &lockcalls, &gcalls, 884 #endif 885 0); 886 #ifdef CALLOUT_PROFILING 887 ++depth; 888 #endif 889 } 890 #ifdef CALLOUT_PROFILING 891 avg_depth += (depth * 1000 - avg_depth) >> 8; 892 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 893 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 894 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 895 #endif 896 CC_UNLOCK(cc); 897 } 898 899 /* 900 * timeout -- 901 * Execute a function after a specified length of time. 902 * 903 * untimeout -- 904 * Cancel previous timeout function call. 905 * 906 * callout_handle_init -- 907 * Initialize a handle so that using it with untimeout is benign. 908 * 909 * See AT&T BCI Driver Reference Manual for specification. This 910 * implementation differs from that one in that although an 911 * identification value is returned from timeout, the original 912 * arguments to timeout as well as the identifier are used to 913 * identify entries for untimeout. 914 */ 915 struct callout_handle 916 timeout(timeout_t *ftn, void *arg, int to_ticks) 917 { 918 struct callout_cpu *cc; 919 struct callout *new; 920 struct callout_handle handle; 921 922 cc = CC_CPU(timeout_cpu); 923 CC_LOCK(cc); 924 /* Fill in the next free callout structure. */ 925 new = SLIST_FIRST(&cc->cc_callfree); 926 if (new == NULL) 927 /* XXX Attempt to malloc first */ 928 panic("timeout table full"); 929 SLIST_REMOVE_HEAD(&cc->cc_callfree, c_links.sle); 930 callout_reset(new, to_ticks, ftn, arg); 931 handle.callout = new; 932 CC_UNLOCK(cc); 933 934 return (handle); 935 } 936 937 void 938 untimeout(timeout_t *ftn, void *arg, struct callout_handle handle) 939 { 940 struct callout_cpu *cc; 941 942 /* 943 * Check for a handle that was initialized 944 * by callout_handle_init, but never used 945 * for a real timeout. 946 */ 947 if (handle.callout == NULL) 948 return; 949 950 cc = callout_lock(handle.callout); 951 if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) 952 callout_stop(handle.callout); 953 CC_UNLOCK(cc); 954 } 955 956 void 957 callout_handle_init(struct callout_handle *handle) 958 { 959 handle->callout = NULL; 960 } 961 962 void 963 callout_when(sbintime_t sbt, sbintime_t precision, int flags, 964 sbintime_t *res, sbintime_t *prec_res) 965 { 966 sbintime_t to_sbt, to_pr; 967 968 if ((flags & (C_ABSOLUTE | C_PRECALC)) != 0) { 969 *res = sbt; 970 *prec_res = precision; 971 return; 972 } 973 if ((flags & C_HARDCLOCK) != 0 && sbt < tick_sbt) 974 sbt = tick_sbt; 975 if ((flags & C_HARDCLOCK) != 0 || 976 #ifdef NO_EVENTTIMERS 977 sbt >= sbt_timethreshold) { 978 to_sbt = getsbinuptime(); 979 980 /* Add safety belt for the case of hz > 1000. */ 981 to_sbt += tc_tick_sbt - tick_sbt; 982 #else 983 sbt >= sbt_tickthreshold) { 984 /* 985 * Obtain the time of the last hardclock() call on 986 * this CPU directly from the kern_clocksource.c. 987 * This value is per-CPU, but it is equal for all 988 * active ones. 989 */ 990 #ifdef __LP64__ 991 to_sbt = DPCPU_GET(hardclocktime); 992 #else 993 spinlock_enter(); 994 to_sbt = DPCPU_GET(hardclocktime); 995 spinlock_exit(); 996 #endif 997 #endif 998 if (cold && to_sbt == 0) 999 to_sbt = sbinuptime(); 1000 if ((flags & C_HARDCLOCK) == 0) 1001 to_sbt += tick_sbt; 1002 } else 1003 to_sbt = sbinuptime(); 1004 if (SBT_MAX - to_sbt < sbt) 1005 to_sbt = SBT_MAX; 1006 else 1007 to_sbt += sbt; 1008 *res = to_sbt; 1009 to_pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : 1010 sbt >> C_PRELGET(flags)); 1011 *prec_res = to_pr > precision ? to_pr : precision; 1012 } 1013 1014 /* 1015 * New interface; clients allocate their own callout structures. 1016 * 1017 * callout_reset() - establish or change a timeout 1018 * callout_stop() - disestablish a timeout 1019 * callout_init() - initialize a callout structure so that it can 1020 * safely be passed to callout_reset() and callout_stop() 1021 * 1022 * <sys/callout.h> defines three convenience macros: 1023 * 1024 * callout_active() - returns truth if callout has not been stopped, 1025 * drained, or deactivated since the last time the callout was 1026 * reset. 1027 * callout_pending() - returns truth if callout is still waiting for timeout 1028 * callout_deactivate() - marks the callout as having been serviced 1029 */ 1030 int 1031 callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t prec, 1032 callout_func_t *ftn, void *arg, int cpu, int flags) 1033 { 1034 sbintime_t to_sbt, precision; 1035 struct callout_cpu *cc; 1036 int cancelled, direct; 1037 int ignore_cpu=0; 1038 1039 cancelled = 0; 1040 if (cpu == -1) { 1041 ignore_cpu = 1; 1042 } else if ((cpu >= MAXCPU) || 1043 ((CC_CPU(cpu))->cc_inited == 0)) { 1044 /* Invalid CPU spec */ 1045 panic("Invalid CPU in callout %d", cpu); 1046 } 1047 callout_when(sbt, prec, flags, &to_sbt, &precision); 1048 1049 /* 1050 * This flag used to be added by callout_cc_add, but the 1051 * first time you call this we could end up with the 1052 * wrong direct flag if we don't do it before we add. 1053 */ 1054 if (flags & C_DIRECT_EXEC) { 1055 direct = 1; 1056 } else { 1057 direct = 0; 1058 } 1059 KASSERT(!direct || c->c_lock == NULL, 1060 ("%s: direct callout %p has lock", __func__, c)); 1061 cc = callout_lock(c); 1062 /* 1063 * Don't allow migration of pre-allocated callouts lest they 1064 * become unbalanced or handle the case where the user does 1065 * not care. 1066 */ 1067 if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) || 1068 ignore_cpu) { 1069 cpu = c->c_cpu; 1070 } 1071 1072 if (cc_exec_curr(cc, direct) == c) { 1073 /* 1074 * We're being asked to reschedule a callout which is 1075 * currently in progress. If there is a lock then we 1076 * can cancel the callout if it has not really started. 1077 */ 1078 if (c->c_lock != NULL && !cc_exec_cancel(cc, direct)) 1079 cancelled = cc_exec_cancel(cc, direct) = true; 1080 if (cc_exec_waiting(cc, direct) || cc_exec_drain(cc, direct)) { 1081 /* 1082 * Someone has called callout_drain to kill this 1083 * callout. Don't reschedule. 1084 */ 1085 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 1086 cancelled ? "cancelled" : "failed to cancel", 1087 c, c->c_func, c->c_arg); 1088 CC_UNLOCK(cc); 1089 return (cancelled); 1090 } 1091 #ifdef SMP 1092 if (callout_migrating(c)) { 1093 /* 1094 * This only occurs when a second callout_reset_sbt_on 1095 * is made after a previous one moved it into 1096 * deferred migration (below). Note we do *not* change 1097 * the prev_cpu even though the previous target may 1098 * be different. 1099 */ 1100 cc_migration_cpu(cc, direct) = cpu; 1101 cc_migration_time(cc, direct) = to_sbt; 1102 cc_migration_prec(cc, direct) = precision; 1103 cc_migration_func(cc, direct) = ftn; 1104 cc_migration_arg(cc, direct) = arg; 1105 cancelled = 1; 1106 CC_UNLOCK(cc); 1107 return (cancelled); 1108 } 1109 #endif 1110 } 1111 if (c->c_iflags & CALLOUT_PENDING) { 1112 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1113 if (cc_exec_next(cc) == c) 1114 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1115 LIST_REMOVE(c, c_links.le); 1116 } else { 1117 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1118 } 1119 cancelled = 1; 1120 c->c_iflags &= ~ CALLOUT_PENDING; 1121 c->c_flags &= ~ CALLOUT_ACTIVE; 1122 } 1123 1124 #ifdef SMP 1125 /* 1126 * If the callout must migrate try to perform it immediately. 1127 * If the callout is currently running, just defer the migration 1128 * to a more appropriate moment. 1129 */ 1130 if (c->c_cpu != cpu) { 1131 if (cc_exec_curr(cc, direct) == c) { 1132 /* 1133 * Pending will have been removed since we are 1134 * actually executing the callout on another 1135 * CPU. That callout should be waiting on the 1136 * lock the caller holds. If we set both 1137 * active/and/pending after we return and the 1138 * lock on the executing callout proceeds, it 1139 * will then see pending is true and return. 1140 * At the return from the actual callout execution 1141 * the migration will occur in softclock_call_cc 1142 * and this new callout will be placed on the 1143 * new CPU via a call to callout_cpu_switch() which 1144 * will get the lock on the right CPU followed 1145 * by a call callout_cc_add() which will add it there. 1146 * (see above in softclock_call_cc()). 1147 */ 1148 cc_migration_cpu(cc, direct) = cpu; 1149 cc_migration_time(cc, direct) = to_sbt; 1150 cc_migration_prec(cc, direct) = precision; 1151 cc_migration_func(cc, direct) = ftn; 1152 cc_migration_arg(cc, direct) = arg; 1153 c->c_iflags |= (CALLOUT_DFRMIGRATION | CALLOUT_PENDING); 1154 c->c_flags |= CALLOUT_ACTIVE; 1155 CTR6(KTR_CALLOUT, 1156 "migration of %p func %p arg %p in %d.%08x to %u deferred", 1157 c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1158 (u_int)(to_sbt & 0xffffffff), cpu); 1159 CC_UNLOCK(cc); 1160 return (cancelled); 1161 } 1162 cc = callout_cpu_switch(c, cc, cpu); 1163 } 1164 #endif 1165 1166 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags); 1167 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", 1168 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1169 (u_int)(to_sbt & 0xffffffff)); 1170 CC_UNLOCK(cc); 1171 1172 return (cancelled); 1173 } 1174 1175 /* 1176 * Common idioms that can be optimized in the future. 1177 */ 1178 int 1179 callout_schedule_on(struct callout *c, int to_ticks, int cpu) 1180 { 1181 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 1182 } 1183 1184 int 1185 callout_schedule(struct callout *c, int to_ticks) 1186 { 1187 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 1188 } 1189 1190 int 1191 _callout_stop_safe(struct callout *c, int flags, callout_func_t *drain) 1192 { 1193 struct callout_cpu *cc, *old_cc; 1194 struct lock_class *class; 1195 int direct, sq_locked, use_lock; 1196 int cancelled, not_on_a_list; 1197 1198 if ((flags & CS_DRAIN) != 0) 1199 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock, 1200 "calling %s", __func__); 1201 1202 /* 1203 * Some old subsystems don't hold Giant while running a callout_stop(), 1204 * so just discard this check for the moment. 1205 */ 1206 if ((flags & CS_DRAIN) == 0 && c->c_lock != NULL) { 1207 if (c->c_lock == &Giant.lock_object) 1208 use_lock = mtx_owned(&Giant); 1209 else { 1210 use_lock = 1; 1211 class = LOCK_CLASS(c->c_lock); 1212 class->lc_assert(c->c_lock, LA_XLOCKED); 1213 } 1214 } else 1215 use_lock = 0; 1216 if (c->c_iflags & CALLOUT_DIRECT) { 1217 direct = 1; 1218 } else { 1219 direct = 0; 1220 } 1221 sq_locked = 0; 1222 old_cc = NULL; 1223 again: 1224 cc = callout_lock(c); 1225 1226 if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) == 1227 (CALLOUT_DFRMIGRATION | CALLOUT_PENDING) && 1228 ((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) { 1229 /* 1230 * Special case where this slipped in while we 1231 * were migrating *as* the callout is about to 1232 * execute. The caller probably holds the lock 1233 * the callout wants. 1234 * 1235 * Get rid of the migration first. Then set 1236 * the flag that tells this code *not* to 1237 * try to remove it from any lists (its not 1238 * on one yet). When the callout wheel runs, 1239 * it will ignore this callout. 1240 */ 1241 c->c_iflags &= ~CALLOUT_PENDING; 1242 c->c_flags &= ~CALLOUT_ACTIVE; 1243 not_on_a_list = 1; 1244 } else { 1245 not_on_a_list = 0; 1246 } 1247 1248 /* 1249 * If the callout was migrating while the callout cpu lock was 1250 * dropped, just drop the sleepqueue lock and check the states 1251 * again. 1252 */ 1253 if (sq_locked != 0 && cc != old_cc) { 1254 #ifdef SMP 1255 CC_UNLOCK(cc); 1256 sleepq_release(&cc_exec_waiting(old_cc, direct)); 1257 sq_locked = 0; 1258 old_cc = NULL; 1259 goto again; 1260 #else 1261 panic("migration should not happen"); 1262 #endif 1263 } 1264 1265 /* 1266 * If the callout is running, try to stop it or drain it. 1267 */ 1268 if (cc_exec_curr(cc, direct) == c) { 1269 /* 1270 * Succeed we to stop it or not, we must clear the 1271 * active flag - this is what API users expect. If we're 1272 * draining and the callout is currently executing, first wait 1273 * until it finishes. 1274 */ 1275 if ((flags & CS_DRAIN) == 0) 1276 c->c_flags &= ~CALLOUT_ACTIVE; 1277 1278 if ((flags & CS_DRAIN) != 0) { 1279 /* 1280 * The current callout is running (or just 1281 * about to run) and blocking is allowed, so 1282 * just wait for the current invocation to 1283 * finish. 1284 */ 1285 while (cc_exec_curr(cc, direct) == c) { 1286 /* 1287 * Use direct calls to sleepqueue interface 1288 * instead of cv/msleep in order to avoid 1289 * a LOR between cc_lock and sleepqueue 1290 * chain spinlocks. This piece of code 1291 * emulates a msleep_spin() call actually. 1292 * 1293 * If we already have the sleepqueue chain 1294 * locked, then we can safely block. If we 1295 * don't already have it locked, however, 1296 * we have to drop the cc_lock to lock 1297 * it. This opens several races, so we 1298 * restart at the beginning once we have 1299 * both locks. If nothing has changed, then 1300 * we will end up back here with sq_locked 1301 * set. 1302 */ 1303 if (!sq_locked) { 1304 CC_UNLOCK(cc); 1305 sleepq_lock( 1306 &cc_exec_waiting(cc, direct)); 1307 sq_locked = 1; 1308 old_cc = cc; 1309 goto again; 1310 } 1311 1312 /* 1313 * Migration could be cancelled here, but 1314 * as long as it is still not sure when it 1315 * will be packed up, just let softclock() 1316 * take care of it. 1317 */ 1318 cc_exec_waiting(cc, direct) = true; 1319 DROP_GIANT(); 1320 CC_UNLOCK(cc); 1321 sleepq_add( 1322 &cc_exec_waiting(cc, direct), 1323 &cc->cc_lock.lock_object, "codrain", 1324 SLEEPQ_SLEEP, 0); 1325 sleepq_wait( 1326 &cc_exec_waiting(cc, direct), 1327 0); 1328 sq_locked = 0; 1329 old_cc = NULL; 1330 1331 /* Reacquire locks previously released. */ 1332 PICKUP_GIANT(); 1333 CC_LOCK(cc); 1334 } 1335 c->c_flags &= ~CALLOUT_ACTIVE; 1336 } else if (use_lock && 1337 !cc_exec_cancel(cc, direct) && (drain == NULL)) { 1338 1339 /* 1340 * The current callout is waiting for its 1341 * lock which we hold. Cancel the callout 1342 * and return. After our caller drops the 1343 * lock, the callout will be skipped in 1344 * softclock(). This *only* works with a 1345 * callout_stop() *not* callout_drain() or 1346 * callout_async_drain(). 1347 */ 1348 cc_exec_cancel(cc, direct) = true; 1349 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1350 c, c->c_func, c->c_arg); 1351 KASSERT(!cc_cce_migrating(cc, direct), 1352 ("callout wrongly scheduled for migration")); 1353 if (callout_migrating(c)) { 1354 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1355 #ifdef SMP 1356 cc_migration_cpu(cc, direct) = CPUBLOCK; 1357 cc_migration_time(cc, direct) = 0; 1358 cc_migration_prec(cc, direct) = 0; 1359 cc_migration_func(cc, direct) = NULL; 1360 cc_migration_arg(cc, direct) = NULL; 1361 #endif 1362 } 1363 CC_UNLOCK(cc); 1364 KASSERT(!sq_locked, ("sleepqueue chain locked")); 1365 return (1); 1366 } else if (callout_migrating(c)) { 1367 /* 1368 * The callout is currently being serviced 1369 * and the "next" callout is scheduled at 1370 * its completion with a migration. We remove 1371 * the migration flag so it *won't* get rescheduled, 1372 * but we can't stop the one thats running so 1373 * we return 0. 1374 */ 1375 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1376 #ifdef SMP 1377 /* 1378 * We can't call cc_cce_cleanup here since 1379 * if we do it will remove .ce_curr and 1380 * its still running. This will prevent a 1381 * reschedule of the callout when the 1382 * execution completes. 1383 */ 1384 cc_migration_cpu(cc, direct) = CPUBLOCK; 1385 cc_migration_time(cc, direct) = 0; 1386 cc_migration_prec(cc, direct) = 0; 1387 cc_migration_func(cc, direct) = NULL; 1388 cc_migration_arg(cc, direct) = NULL; 1389 #endif 1390 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 1391 c, c->c_func, c->c_arg); 1392 if (drain) { 1393 cc_exec_drain(cc, direct) = drain; 1394 } 1395 CC_UNLOCK(cc); 1396 return ((flags & CS_EXECUTING) != 0); 1397 } 1398 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1399 c, c->c_func, c->c_arg); 1400 if (drain) { 1401 cc_exec_drain(cc, direct) = drain; 1402 } 1403 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 1404 cancelled = ((flags & CS_EXECUTING) != 0); 1405 } else 1406 cancelled = 1; 1407 1408 if (sq_locked) 1409 sleepq_release(&cc_exec_waiting(cc, direct)); 1410 1411 if ((c->c_iflags & CALLOUT_PENDING) == 0) { 1412 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1413 c, c->c_func, c->c_arg); 1414 /* 1415 * For not scheduled and not executing callout return 1416 * negative value. 1417 */ 1418 if (cc_exec_curr(cc, direct) != c) 1419 cancelled = -1; 1420 CC_UNLOCK(cc); 1421 return (cancelled); 1422 } 1423 1424 c->c_iflags &= ~CALLOUT_PENDING; 1425 c->c_flags &= ~CALLOUT_ACTIVE; 1426 1427 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1428 c, c->c_func, c->c_arg); 1429 if (not_on_a_list == 0) { 1430 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1431 if (cc_exec_next(cc) == c) 1432 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1433 LIST_REMOVE(c, c_links.le); 1434 } else { 1435 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1436 } 1437 } 1438 callout_cc_del(c, cc); 1439 CC_UNLOCK(cc); 1440 return (cancelled); 1441 } 1442 1443 void 1444 callout_init(struct callout *c, int mpsafe) 1445 { 1446 bzero(c, sizeof *c); 1447 if (mpsafe) { 1448 c->c_lock = NULL; 1449 c->c_iflags = CALLOUT_RETURNUNLOCKED; 1450 } else { 1451 c->c_lock = &Giant.lock_object; 1452 c->c_iflags = 0; 1453 } 1454 c->c_cpu = timeout_cpu; 1455 } 1456 1457 void 1458 _callout_init_lock(struct callout *c, struct lock_object *lock, int flags) 1459 { 1460 bzero(c, sizeof *c); 1461 c->c_lock = lock; 1462 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1463 ("callout_init_lock: bad flags %d", flags)); 1464 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1465 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1466 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & 1467 (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class", 1468 __func__)); 1469 c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1470 c->c_cpu = timeout_cpu; 1471 } 1472 1473 #ifdef APM_FIXUP_CALLTODO 1474 /* 1475 * Adjust the kernel calltodo timeout list. This routine is used after 1476 * an APM resume to recalculate the calltodo timer list values with the 1477 * number of hz's we have been sleeping. The next hardclock() will detect 1478 * that there are fired timers and run softclock() to execute them. 1479 * 1480 * Please note, I have not done an exhaustive analysis of what code this 1481 * might break. I am motivated to have my select()'s and alarm()'s that 1482 * have expired during suspend firing upon resume so that the applications 1483 * which set the timer can do the maintanence the timer was for as close 1484 * as possible to the originally intended time. Testing this code for a 1485 * week showed that resuming from a suspend resulted in 22 to 25 timers 1486 * firing, which seemed independent on whether the suspend was 2 hours or 1487 * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu> 1488 */ 1489 void 1490 adjust_timeout_calltodo(struct timeval *time_change) 1491 { 1492 struct callout *p; 1493 unsigned long delta_ticks; 1494 1495 /* 1496 * How many ticks were we asleep? 1497 * (stolen from tvtohz()). 1498 */ 1499 1500 /* Don't do anything */ 1501 if (time_change->tv_sec < 0) 1502 return; 1503 else if (time_change->tv_sec <= LONG_MAX / 1000000) 1504 delta_ticks = howmany(time_change->tv_sec * 1000000 + 1505 time_change->tv_usec, tick) + 1; 1506 else if (time_change->tv_sec <= LONG_MAX / hz) 1507 delta_ticks = time_change->tv_sec * hz + 1508 howmany(time_change->tv_usec, tick) + 1; 1509 else 1510 delta_ticks = LONG_MAX; 1511 1512 if (delta_ticks > INT_MAX) 1513 delta_ticks = INT_MAX; 1514 1515 /* 1516 * Now rip through the timer calltodo list looking for timers 1517 * to expire. 1518 */ 1519 1520 /* don't collide with softclock() */ 1521 CC_LOCK(cc); 1522 for (p = calltodo.c_next; p != NULL; p = p->c_next) { 1523 p->c_time -= delta_ticks; 1524 1525 /* Break if the timer had more time on it than delta_ticks */ 1526 if (p->c_time > 0) 1527 break; 1528 1529 /* take back the ticks the timer didn't use (p->c_time <= 0) */ 1530 delta_ticks = -p->c_time; 1531 } 1532 CC_UNLOCK(cc); 1533 1534 return; 1535 } 1536 #endif /* APM_FIXUP_CALLTODO */ 1537 1538 static int 1539 flssbt(sbintime_t sbt) 1540 { 1541 1542 sbt += (uint64_t)sbt >> 1; 1543 if (sizeof(long) >= sizeof(sbintime_t)) 1544 return (flsl(sbt)); 1545 if (sbt >= SBT_1S) 1546 return (flsl(((uint64_t)sbt) >> 32) + 32); 1547 return (flsl(sbt)); 1548 } 1549 1550 /* 1551 * Dump immediate statistic snapshot of the scheduled callouts. 1552 */ 1553 static int 1554 sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1555 { 1556 struct callout *tmp; 1557 struct callout_cpu *cc; 1558 struct callout_list *sc; 1559 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; 1560 int ct[64], cpr[64], ccpbk[32]; 1561 int error, val, i, count, tcum, pcum, maxc, c, medc; 1562 #ifdef SMP 1563 int cpu; 1564 #endif 1565 1566 val = 0; 1567 error = sysctl_handle_int(oidp, &val, 0, req); 1568 if (error != 0 || req->newptr == NULL) 1569 return (error); 1570 count = maxc = 0; 1571 st = spr = maxt = maxpr = 0; 1572 bzero(ccpbk, sizeof(ccpbk)); 1573 bzero(ct, sizeof(ct)); 1574 bzero(cpr, sizeof(cpr)); 1575 now = sbinuptime(); 1576 #ifdef SMP 1577 CPU_FOREACH(cpu) { 1578 cc = CC_CPU(cpu); 1579 #else 1580 cc = CC_CPU(timeout_cpu); 1581 #endif 1582 CC_LOCK(cc); 1583 for (i = 0; i < callwheelsize; i++) { 1584 sc = &cc->cc_callwheel[i]; 1585 c = 0; 1586 LIST_FOREACH(tmp, sc, c_links.le) { 1587 c++; 1588 t = tmp->c_time - now; 1589 if (t < 0) 1590 t = 0; 1591 st += t / SBT_1US; 1592 spr += tmp->c_precision / SBT_1US; 1593 if (t > maxt) 1594 maxt = t; 1595 if (tmp->c_precision > maxpr) 1596 maxpr = tmp->c_precision; 1597 ct[flssbt(t)]++; 1598 cpr[flssbt(tmp->c_precision)]++; 1599 } 1600 if (c > maxc) 1601 maxc = c; 1602 ccpbk[fls(c + c / 2)]++; 1603 count += c; 1604 } 1605 CC_UNLOCK(cc); 1606 #ifdef SMP 1607 } 1608 #endif 1609 1610 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1611 tcum += ct[i]; 1612 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1613 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) 1614 pcum += cpr[i]; 1615 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1616 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1617 c += ccpbk[i]; 1618 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1619 1620 printf("Scheduled callouts statistic snapshot:\n"); 1621 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1622 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1623 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1624 medc, 1625 count / callwheelsize / mp_ncpus, 1626 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1627 maxc); 1628 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1629 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1630 (st / count) / 1000000, (st / count) % 1000000, 1631 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); 1632 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1633 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, 1634 (spr / count) / 1000000, (spr / count) % 1000000, 1635 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); 1636 printf(" Distribution: \tbuckets\t time\t tcum\t" 1637 " prec\t pcum\n"); 1638 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1639 if (ct[i] == 0 && cpr[i] == 0) 1640 continue; 1641 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1642 tcum += ct[i]; 1643 pcum += cpr[i]; 1644 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", 1645 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1646 i - 1 - (32 - CC_HASH_SHIFT), 1647 ct[i], tcum, cpr[i], pcum); 1648 } 1649 return (error); 1650 } 1651 SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1652 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1653 0, 0, sysctl_kern_callout_stat, "I", 1654 "Dump immediate statistic snapshot of the scheduled callouts"); 1655 1656 #ifdef DDB 1657 static void 1658 _show_callout(struct callout *c) 1659 { 1660 1661 db_printf("callout %p\n", c); 1662 #define C_DB_PRINTF(f, e) db_printf(" %s = " f "\n", #e, c->e); 1663 db_printf(" &c_links = %p\n", &(c->c_links)); 1664 C_DB_PRINTF("%" PRId64, c_time); 1665 C_DB_PRINTF("%" PRId64, c_precision); 1666 C_DB_PRINTF("%p", c_arg); 1667 C_DB_PRINTF("%p", c_func); 1668 C_DB_PRINTF("%p", c_lock); 1669 C_DB_PRINTF("%#x", c_flags); 1670 C_DB_PRINTF("%#x", c_iflags); 1671 C_DB_PRINTF("%d", c_cpu); 1672 #undef C_DB_PRINTF 1673 } 1674 1675 DB_SHOW_COMMAND(callout, db_show_callout) 1676 { 1677 1678 if (!have_addr) { 1679 db_printf("usage: show callout <struct callout *>\n"); 1680 return; 1681 } 1682 1683 _show_callout((struct callout *)addr); 1684 } 1685 1686 static void 1687 _show_last_callout(int cpu, int direct, const char *dirstr) 1688 { 1689 struct callout_cpu *cc; 1690 void *func, *arg; 1691 1692 cc = CC_CPU(cpu); 1693 func = cc_exec_last_func(cc, direct); 1694 arg = cc_exec_last_arg(cc, direct); 1695 db_printf("cpu %d last%s callout function: %p ", cpu, dirstr, func); 1696 db_printsym((db_expr_t)func, DB_STGY_ANY); 1697 db_printf("\ncpu %d last%s callout argument: %p\n", cpu, dirstr, arg); 1698 } 1699 1700 DB_SHOW_COMMAND(callout_last, db_show_callout_last) 1701 { 1702 int cpu, last; 1703 1704 if (have_addr) { 1705 if (addr < 0 || addr > mp_maxid || CPU_ABSENT(addr)) { 1706 db_printf("no such cpu: %d\n", (int)addr); 1707 return; 1708 } 1709 cpu = last = addr; 1710 } else { 1711 cpu = 0; 1712 last = mp_maxid; 1713 } 1714 1715 while (cpu <= last) { 1716 if (!CPU_ABSENT(cpu)) { 1717 _show_last_callout(cpu, 0, ""); 1718 _show_last_callout(cpu, 1, " direct"); 1719 } 1720 cpu++; 1721 } 1722 } 1723 #endif /* DDB */ 1724