1 /*- 2 * Copyright (c) 1982, 1986, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include "opt_callout_profiling.h" 41 #if defined(__arm__) 42 #include "opt_timer.h" 43 #endif 44 #include "opt_rss.h" 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/bus.h> 49 #include <sys/callout.h> 50 #include <sys/file.h> 51 #include <sys/interrupt.h> 52 #include <sys/kernel.h> 53 #include <sys/ktr.h> 54 #include <sys/lock.h> 55 #include <sys/malloc.h> 56 #include <sys/mutex.h> 57 #include <sys/proc.h> 58 #include <sys/sdt.h> 59 #include <sys/sleepqueue.h> 60 #include <sys/sysctl.h> 61 #include <sys/smp.h> 62 63 #ifdef SMP 64 #include <machine/cpu.h> 65 #endif 66 67 #ifndef NO_EVENTTIMERS 68 DPCPU_DECLARE(sbintime_t, hardclocktime); 69 #endif 70 71 SDT_PROVIDER_DEFINE(callout_execute); 72 SDT_PROBE_DEFINE1(callout_execute, kernel, , callout__start, 73 "struct callout *"); 74 SDT_PROBE_DEFINE1(callout_execute, kernel, , callout__end, 75 "struct callout *"); 76 77 #ifdef CALLOUT_PROFILING 78 static int avg_depth; 79 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, 80 "Average number of items examined per softclock call. Units = 1/1000"); 81 static int avg_gcalls; 82 SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, 83 "Average number of Giant callouts made per softclock call. Units = 1/1000"); 84 static int avg_lockcalls; 85 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0, 86 "Average number of lock callouts made per softclock call. Units = 1/1000"); 87 static int avg_mpcalls; 88 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, 89 "Average number of MP callouts made per softclock call. Units = 1/1000"); 90 static int avg_depth_dir; 91 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0, 92 "Average number of direct callouts examined per callout_process call. " 93 "Units = 1/1000"); 94 static int avg_lockcalls_dir; 95 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD, 96 &avg_lockcalls_dir, 0, "Average number of lock direct callouts made per " 97 "callout_process call. Units = 1/1000"); 98 static int avg_mpcalls_dir; 99 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir, 100 0, "Average number of MP direct callouts made per callout_process call. " 101 "Units = 1/1000"); 102 #endif 103 104 static int ncallout; 105 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &ncallout, 0, 106 "Number of entries in callwheel and size of timeout() preallocation"); 107 108 #ifdef RSS 109 static int pin_default_swi = 1; 110 static int pin_pcpu_swi = 1; 111 #else 112 static int pin_default_swi = 0; 113 static int pin_pcpu_swi = 0; 114 #endif 115 116 SYSCTL_INT(_kern, OID_AUTO, pin_default_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_default_swi, 117 0, "Pin the default (non-per-cpu) swi (shared with PCPU 0 swi)"); 118 SYSCTL_INT(_kern, OID_AUTO, pin_pcpu_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_pcpu_swi, 119 0, "Pin the per-CPU swis (except PCPU 0, which is also default"); 120 121 /* 122 * TODO: 123 * allocate more timeout table slots when table overflows. 124 */ 125 u_int callwheelsize, callwheelmask; 126 127 /* 128 * The callout cpu exec entities represent informations necessary for 129 * describing the state of callouts currently running on the CPU and the ones 130 * necessary for migrating callouts to the new callout cpu. In particular, 131 * the first entry of the array cc_exec_entity holds informations for callout 132 * running in SWI thread context, while the second one holds informations 133 * for callout running directly from hardware interrupt context. 134 * The cached informations are very important for deferring migration when 135 * the migrating callout is already running. 136 */ 137 struct cc_exec { 138 struct callout *cc_next; 139 struct callout *cc_curr; 140 #ifdef SMP 141 void (*ce_migration_func)(void *); 142 void *ce_migration_arg; 143 int ce_migration_cpu; 144 sbintime_t ce_migration_time; 145 sbintime_t ce_migration_prec; 146 #endif 147 bool cc_cancel; 148 bool cc_waiting; 149 }; 150 151 /* 152 * There is one struct callout_cpu per cpu, holding all relevant 153 * state for the callout processing thread on the individual CPU. 154 */ 155 struct callout_cpu { 156 struct mtx_padalign cc_lock; 157 struct cc_exec cc_exec_entity[2]; 158 struct callout *cc_callout; 159 struct callout_list *cc_callwheel; 160 struct callout_tailq cc_expireq; 161 struct callout_slist cc_callfree; 162 sbintime_t cc_firstevent; 163 sbintime_t cc_lastscan; 164 void *cc_cookie; 165 u_int cc_bucket; 166 char cc_ktr_event_name[20]; 167 }; 168 169 #define cc_exec_curr cc_exec_entity[0].cc_curr 170 #define cc_exec_next cc_exec_entity[0].cc_next 171 #define cc_exec_cancel cc_exec_entity[0].cc_cancel 172 #define cc_exec_waiting cc_exec_entity[0].cc_waiting 173 #define cc_exec_curr_dir cc_exec_entity[1].cc_curr 174 #define cc_exec_next_dir cc_exec_entity[1].cc_next 175 #define cc_exec_cancel_dir cc_exec_entity[1].cc_cancel 176 #define cc_exec_waiting_dir cc_exec_entity[1].cc_waiting 177 178 #ifdef SMP 179 #define cc_migration_func cc_exec_entity[0].ce_migration_func 180 #define cc_migration_arg cc_exec_entity[0].ce_migration_arg 181 #define cc_migration_cpu cc_exec_entity[0].ce_migration_cpu 182 #define cc_migration_time cc_exec_entity[0].ce_migration_time 183 #define cc_migration_prec cc_exec_entity[0].ce_migration_prec 184 #define cc_migration_func_dir cc_exec_entity[1].ce_migration_func 185 #define cc_migration_arg_dir cc_exec_entity[1].ce_migration_arg 186 #define cc_migration_cpu_dir cc_exec_entity[1].ce_migration_cpu 187 #define cc_migration_time_dir cc_exec_entity[1].ce_migration_time 188 #define cc_migration_prec_dir cc_exec_entity[1].ce_migration_prec 189 190 struct callout_cpu cc_cpu[MAXCPU]; 191 #define CPUBLOCK MAXCPU 192 #define CC_CPU(cpu) (&cc_cpu[(cpu)]) 193 #define CC_SELF() CC_CPU(PCPU_GET(cpuid)) 194 #else 195 struct callout_cpu cc_cpu; 196 #define CC_CPU(cpu) &cc_cpu 197 #define CC_SELF() &cc_cpu 198 #endif 199 #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) 200 #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) 201 #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) 202 203 static int timeout_cpu; 204 205 static void callout_cpu_init(struct callout_cpu *cc, int cpu); 206 static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, 207 #ifdef CALLOUT_PROFILING 208 int *mpcalls, int *lockcalls, int *gcalls, 209 #endif 210 int direct); 211 212 static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); 213 214 /** 215 * Locked by cc_lock: 216 * cc_curr - If a callout is in progress, it is cc_curr. 217 * If cc_curr is non-NULL, threads waiting in 218 * callout_drain() will be woken up as soon as the 219 * relevant callout completes. 220 * cc_cancel - Changing to 1 with both callout_lock and cc_lock held 221 * guarantees that the current callout will not run. 222 * The softclock() function sets this to 0 before it 223 * drops callout_lock to acquire c_lock, and it calls 224 * the handler only if curr_cancelled is still 0 after 225 * cc_lock is successfully acquired. 226 * cc_waiting - If a thread is waiting in callout_drain(), then 227 * callout_wait is nonzero. Set only when 228 * cc_curr is non-NULL. 229 */ 230 231 /* 232 * Resets the execution entity tied to a specific callout cpu. 233 */ 234 static void 235 cc_cce_cleanup(struct callout_cpu *cc, int direct) 236 { 237 238 cc->cc_exec_entity[direct].cc_curr = NULL; 239 cc->cc_exec_entity[direct].cc_next = NULL; 240 cc->cc_exec_entity[direct].cc_cancel = false; 241 cc->cc_exec_entity[direct].cc_waiting = false; 242 #ifdef SMP 243 cc->cc_exec_entity[direct].ce_migration_cpu = CPUBLOCK; 244 cc->cc_exec_entity[direct].ce_migration_time = 0; 245 cc->cc_exec_entity[direct].ce_migration_prec = 0; 246 cc->cc_exec_entity[direct].ce_migration_func = NULL; 247 cc->cc_exec_entity[direct].ce_migration_arg = NULL; 248 #endif 249 } 250 251 /* 252 * Checks if migration is requested by a specific callout cpu. 253 */ 254 static int 255 cc_cce_migrating(struct callout_cpu *cc, int direct) 256 { 257 258 #ifdef SMP 259 return (cc->cc_exec_entity[direct].ce_migration_cpu != CPUBLOCK); 260 #else 261 return (0); 262 #endif 263 } 264 265 /* 266 * Kernel low level callwheel initialization 267 * called on cpu0 during kernel startup. 268 */ 269 static void 270 callout_callwheel_init(void *dummy) 271 { 272 struct callout_cpu *cc; 273 274 /* 275 * Calculate the size of the callout wheel and the preallocated 276 * timeout() structures. 277 * XXX: Clip callout to result of previous function of maxusers 278 * maximum 384. This is still huge, but acceptable. 279 */ 280 ncallout = imin(16 + maxproc + maxfiles, 18508); 281 TUNABLE_INT_FETCH("kern.ncallout", &ncallout); 282 283 /* 284 * Calculate callout wheel size, should be next power of two higher 285 * than 'ncallout'. 286 */ 287 callwheelsize = 1 << fls(ncallout); 288 callwheelmask = callwheelsize - 1; 289 290 /* 291 * Fetch whether we're pinning the swi's or not. 292 */ 293 TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi); 294 TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi); 295 296 /* 297 * Only cpu0 handles timeout(9) and receives a preallocation. 298 * 299 * XXX: Once all timeout(9) consumers are converted this can 300 * be removed. 301 */ 302 timeout_cpu = PCPU_GET(cpuid); 303 cc = CC_CPU(timeout_cpu); 304 cc->cc_callout = malloc(ncallout * sizeof(struct callout), 305 M_CALLOUT, M_WAITOK); 306 callout_cpu_init(cc, timeout_cpu); 307 } 308 SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); 309 310 /* 311 * Initialize the per-cpu callout structures. 312 */ 313 static void 314 callout_cpu_init(struct callout_cpu *cc, int cpu) 315 { 316 struct callout *c; 317 int i; 318 319 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); 320 SLIST_INIT(&cc->cc_callfree); 321 cc->cc_callwheel = malloc(sizeof(struct callout_list) * callwheelsize, 322 M_CALLOUT, M_WAITOK); 323 for (i = 0; i < callwheelsize; i++) 324 LIST_INIT(&cc->cc_callwheel[i]); 325 TAILQ_INIT(&cc->cc_expireq); 326 cc->cc_firstevent = SBT_MAX; 327 for (i = 0; i < 2; i++) 328 cc_cce_cleanup(cc, i); 329 snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name), 330 "callwheel cpu %d", cpu); 331 if (cc->cc_callout == NULL) /* Only cpu0 handles timeout(9) */ 332 return; 333 for (i = 0; i < ncallout; i++) { 334 c = &cc->cc_callout[i]; 335 callout_init(c, 0); 336 c->c_flags = CALLOUT_LOCAL_ALLOC; 337 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 338 } 339 } 340 341 #ifdef SMP 342 /* 343 * Switches the cpu tied to a specific callout. 344 * The function expects a locked incoming callout cpu and returns with 345 * locked outcoming callout cpu. 346 */ 347 static struct callout_cpu * 348 callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu) 349 { 350 struct callout_cpu *new_cc; 351 352 MPASS(c != NULL && cc != NULL); 353 CC_LOCK_ASSERT(cc); 354 355 /* 356 * Avoid interrupts and preemption firing after the callout cpu 357 * is blocked in order to avoid deadlocks as the new thread 358 * may be willing to acquire the callout cpu lock. 359 */ 360 c->c_cpu = CPUBLOCK; 361 spinlock_enter(); 362 CC_UNLOCK(cc); 363 new_cc = CC_CPU(new_cpu); 364 CC_LOCK(new_cc); 365 spinlock_exit(); 366 c->c_cpu = new_cpu; 367 return (new_cc); 368 } 369 #endif 370 371 /* 372 * Start standard softclock thread. 373 */ 374 static void 375 start_softclock(void *dummy) 376 { 377 struct callout_cpu *cc; 378 char name[MAXCOMLEN]; 379 #ifdef SMP 380 int cpu; 381 struct intr_event *ie; 382 #endif 383 384 cc = CC_CPU(timeout_cpu); 385 snprintf(name, sizeof(name), "clock (%d)", timeout_cpu); 386 if (swi_add(&clk_intr_event, name, softclock, cc, SWI_CLOCK, 387 INTR_MPSAFE, &cc->cc_cookie)) 388 panic("died while creating standard software ithreads"); 389 if (pin_default_swi && 390 (intr_event_bind(clk_intr_event, timeout_cpu) != 0)) { 391 printf("%s: timeout clock couldn't be pinned to cpu %d\n", 392 __func__, 393 timeout_cpu); 394 } 395 396 #ifdef SMP 397 CPU_FOREACH(cpu) { 398 if (cpu == timeout_cpu) 399 continue; 400 cc = CC_CPU(cpu); 401 cc->cc_callout = NULL; /* Only cpu0 handles timeout(9). */ 402 callout_cpu_init(cc, cpu); 403 snprintf(name, sizeof(name), "clock (%d)", cpu); 404 ie = NULL; 405 if (swi_add(&ie, name, softclock, cc, SWI_CLOCK, 406 INTR_MPSAFE, &cc->cc_cookie)) 407 panic("died while creating standard software ithreads"); 408 if (pin_pcpu_swi && (intr_event_bind(ie, cpu) != 0)) { 409 printf("%s: per-cpu clock couldn't be pinned to " 410 "cpu %d\n", 411 __func__, 412 cpu); 413 } 414 } 415 #endif 416 } 417 SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); 418 419 #define CC_HASH_SHIFT 8 420 421 static inline u_int 422 callout_hash(sbintime_t sbt) 423 { 424 425 return (sbt >> (32 - CC_HASH_SHIFT)); 426 } 427 428 static inline u_int 429 callout_get_bucket(sbintime_t sbt) 430 { 431 432 return (callout_hash(sbt) & callwheelmask); 433 } 434 435 void 436 callout_process(sbintime_t now) 437 { 438 struct callout *tmp, *tmpn; 439 struct callout_cpu *cc; 440 struct callout_list *sc; 441 sbintime_t first, last, max, tmp_max; 442 uint32_t lookahead; 443 u_int firstb, lastb, nowb; 444 #ifdef CALLOUT_PROFILING 445 int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0; 446 #endif 447 448 cc = CC_SELF(); 449 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET); 450 451 /* Compute the buckets of the last scan and present times. */ 452 firstb = callout_hash(cc->cc_lastscan); 453 cc->cc_lastscan = now; 454 nowb = callout_hash(now); 455 456 /* Compute the last bucket and minimum time of the bucket after it. */ 457 if (nowb == firstb) 458 lookahead = (SBT_1S / 16); 459 else if (nowb - firstb == 1) 460 lookahead = (SBT_1S / 8); 461 else 462 lookahead = (SBT_1S / 2); 463 first = last = now; 464 first += (lookahead / 2); 465 last += lookahead; 466 last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); 467 lastb = callout_hash(last) - 1; 468 max = last; 469 470 /* 471 * Check if we wrapped around the entire wheel from the last scan. 472 * In case, we need to scan entirely the wheel for pending callouts. 473 */ 474 if (lastb - firstb >= callwheelsize) { 475 lastb = firstb + callwheelsize - 1; 476 if (nowb - firstb >= callwheelsize) 477 nowb = lastb; 478 } 479 480 /* Iterate callwheel from firstb to nowb and then up to lastb. */ 481 do { 482 sc = &cc->cc_callwheel[firstb & callwheelmask]; 483 tmp = LIST_FIRST(sc); 484 while (tmp != NULL) { 485 /* Run the callout if present time within allowed. */ 486 if (tmp->c_time <= now) { 487 /* 488 * Consumer told us the callout may be run 489 * directly from hardware interrupt context. 490 */ 491 if (tmp->c_flags & CALLOUT_DIRECT) { 492 #ifdef CALLOUT_PROFILING 493 ++depth_dir; 494 #endif 495 cc->cc_exec_next_dir = 496 LIST_NEXT(tmp, c_links.le); 497 cc->cc_bucket = firstb & callwheelmask; 498 LIST_REMOVE(tmp, c_links.le); 499 softclock_call_cc(tmp, cc, 500 #ifdef CALLOUT_PROFILING 501 &mpcalls_dir, &lockcalls_dir, NULL, 502 #endif 503 1); 504 tmp = cc->cc_exec_next_dir; 505 } else { 506 tmpn = LIST_NEXT(tmp, c_links.le); 507 LIST_REMOVE(tmp, c_links.le); 508 TAILQ_INSERT_TAIL(&cc->cc_expireq, 509 tmp, c_links.tqe); 510 tmp->c_flags |= CALLOUT_PROCESSED; 511 tmp = tmpn; 512 } 513 continue; 514 } 515 /* Skip events from distant future. */ 516 if (tmp->c_time >= max) 517 goto next; 518 /* 519 * Event minimal time is bigger than present maximal 520 * time, so it cannot be aggregated. 521 */ 522 if (tmp->c_time > last) { 523 lastb = nowb; 524 goto next; 525 } 526 /* Update first and last time, respecting this event. */ 527 if (tmp->c_time < first) 528 first = tmp->c_time; 529 tmp_max = tmp->c_time + tmp->c_precision; 530 if (tmp_max < last) 531 last = tmp_max; 532 next: 533 tmp = LIST_NEXT(tmp, c_links.le); 534 } 535 /* Proceed with the next bucket. */ 536 firstb++; 537 /* 538 * Stop if we looked after present time and found 539 * some event we can't execute at now. 540 * Stop if we looked far enough into the future. 541 */ 542 } while (((int)(firstb - lastb)) <= 0); 543 cc->cc_firstevent = last; 544 #ifndef NO_EVENTTIMERS 545 cpu_new_callout(curcpu, last, first); 546 #endif 547 #ifdef CALLOUT_PROFILING 548 avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8; 549 avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8; 550 avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8; 551 #endif 552 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 553 /* 554 * swi_sched acquires the thread lock, so we don't want to call it 555 * with cc_lock held; incorrect locking order. 556 */ 557 if (!TAILQ_EMPTY(&cc->cc_expireq)) 558 swi_sched(cc->cc_cookie, 0); 559 } 560 561 static struct callout_cpu * 562 callout_lock(struct callout *c) 563 { 564 struct callout_cpu *cc; 565 int cpu; 566 567 for (;;) { 568 cpu = c->c_cpu; 569 #ifdef SMP 570 if (cpu == CPUBLOCK) { 571 while (c->c_cpu == CPUBLOCK) 572 cpu_spinwait(); 573 continue; 574 } 575 #endif 576 cc = CC_CPU(cpu); 577 CC_LOCK(cc); 578 if (cpu == c->c_cpu) 579 break; 580 CC_UNLOCK(cc); 581 } 582 return (cc); 583 } 584 585 static void 586 callout_cc_add(struct callout *c, struct callout_cpu *cc, 587 sbintime_t sbt, sbintime_t precision, void (*func)(void *), 588 void *arg, int cpu, int flags) 589 { 590 int bucket; 591 592 CC_LOCK_ASSERT(cc); 593 if (sbt < cc->cc_lastscan) 594 sbt = cc->cc_lastscan; 595 c->c_arg = arg; 596 c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING); 597 if (flags & C_DIRECT_EXEC) 598 c->c_flags |= CALLOUT_DIRECT; 599 c->c_flags &= ~CALLOUT_PROCESSED; 600 c->c_func = func; 601 c->c_time = sbt; 602 c->c_precision = precision; 603 bucket = callout_get_bucket(c->c_time); 604 CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x", 605 c, (int)(c->c_precision >> 32), 606 (u_int)(c->c_precision & 0xffffffff)); 607 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); 608 if (cc->cc_bucket == bucket) 609 cc->cc_exec_next_dir = c; 610 #ifndef NO_EVENTTIMERS 611 /* 612 * Inform the eventtimers(4) subsystem there's a new callout 613 * that has been inserted, but only if really required. 614 */ 615 if (SBT_MAX - c->c_time < c->c_precision) 616 c->c_precision = SBT_MAX - c->c_time; 617 sbt = c->c_time + c->c_precision; 618 if (sbt < cc->cc_firstevent) { 619 cc->cc_firstevent = sbt; 620 cpu_new_callout(cpu, sbt, c->c_time); 621 } 622 #endif 623 } 624 625 static void 626 callout_cc_del(struct callout *c, struct callout_cpu *cc) 627 { 628 629 if ((c->c_flags & CALLOUT_LOCAL_ALLOC) == 0) 630 return; 631 c->c_func = NULL; 632 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 633 } 634 635 static void 636 softclock_call_cc(struct callout *c, struct callout_cpu *cc, 637 #ifdef CALLOUT_PROFILING 638 int *mpcalls, int *lockcalls, int *gcalls, 639 #endif 640 int direct) 641 { 642 struct rm_priotracker tracker; 643 void (*c_func)(void *); 644 void *c_arg; 645 struct lock_class *class; 646 struct lock_object *c_lock; 647 uintptr_t lock_status; 648 int c_flags; 649 #ifdef SMP 650 struct callout_cpu *new_cc; 651 void (*new_func)(void *); 652 void *new_arg; 653 int flags, new_cpu; 654 sbintime_t new_prec, new_time; 655 #endif 656 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 657 sbintime_t sbt1, sbt2; 658 struct timespec ts2; 659 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 660 static timeout_t *lastfunc; 661 #endif 662 663 KASSERT((c->c_flags & (CALLOUT_PENDING | CALLOUT_ACTIVE)) == 664 (CALLOUT_PENDING | CALLOUT_ACTIVE), 665 ("softclock_call_cc: pend|act %p %x", c, c->c_flags)); 666 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; 667 lock_status = 0; 668 if (c->c_flags & CALLOUT_SHAREDLOCK) { 669 if (class == &lock_class_rm) 670 lock_status = (uintptr_t)&tracker; 671 else 672 lock_status = 1; 673 } 674 c_lock = c->c_lock; 675 c_func = c->c_func; 676 c_arg = c->c_arg; 677 c_flags = c->c_flags; 678 if (c->c_flags & CALLOUT_LOCAL_ALLOC) 679 c->c_flags = CALLOUT_LOCAL_ALLOC; 680 else 681 c->c_flags &= ~CALLOUT_PENDING; 682 cc->cc_exec_entity[direct].cc_curr = c; 683 cc->cc_exec_entity[direct].cc_cancel = false; 684 CC_UNLOCK(cc); 685 if (c_lock != NULL) { 686 class->lc_lock(c_lock, lock_status); 687 /* 688 * The callout may have been cancelled 689 * while we switched locks. 690 */ 691 if (cc->cc_exec_entity[direct].cc_cancel) { 692 class->lc_unlock(c_lock); 693 goto skip; 694 } 695 /* The callout cannot be stopped now. */ 696 cc->cc_exec_entity[direct].cc_cancel = true; 697 if (c_lock == &Giant.lock_object) { 698 #ifdef CALLOUT_PROFILING 699 (*gcalls)++; 700 #endif 701 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", 702 c, c_func, c_arg); 703 } else { 704 #ifdef CALLOUT_PROFILING 705 (*lockcalls)++; 706 #endif 707 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", 708 c, c_func, c_arg); 709 } 710 } else { 711 #ifdef CALLOUT_PROFILING 712 (*mpcalls)++; 713 #endif 714 CTR3(KTR_CALLOUT, "callout %p func %p arg %p", 715 c, c_func, c_arg); 716 } 717 KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running", 718 "func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct); 719 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 720 sbt1 = sbinuptime(); 721 #endif 722 THREAD_NO_SLEEPING(); 723 SDT_PROBE(callout_execute, kernel, , callout__start, c, 0, 0, 0, 0); 724 c_func(c_arg); 725 SDT_PROBE(callout_execute, kernel, , callout__end, c, 0, 0, 0, 0); 726 THREAD_SLEEPING_OK(); 727 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 728 sbt2 = sbinuptime(); 729 sbt2 -= sbt1; 730 if (sbt2 > maxdt) { 731 if (lastfunc != c_func || sbt2 > maxdt * 2) { 732 ts2 = sbttots(sbt2); 733 printf( 734 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 735 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); 736 } 737 maxdt = sbt2; 738 lastfunc = c_func; 739 } 740 #endif 741 KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle"); 742 CTR1(KTR_CALLOUT, "callout %p finished", c); 743 if ((c_flags & CALLOUT_RETURNUNLOCKED) == 0) 744 class->lc_unlock(c_lock); 745 skip: 746 CC_LOCK(cc); 747 KASSERT(cc->cc_exec_entity[direct].cc_curr == c, ("mishandled cc_curr")); 748 cc->cc_exec_entity[direct].cc_curr = NULL; 749 if (cc->cc_exec_entity[direct].cc_waiting) { 750 /* 751 * There is someone waiting for the 752 * callout to complete. 753 * If the callout was scheduled for 754 * migration just cancel it. 755 */ 756 if (cc_cce_migrating(cc, direct)) { 757 cc_cce_cleanup(cc, direct); 758 759 /* 760 * It should be assert here that the callout is not 761 * destroyed but that is not easy. 762 */ 763 c->c_flags &= ~CALLOUT_DFRMIGRATION; 764 } 765 cc->cc_exec_entity[direct].cc_waiting = false; 766 CC_UNLOCK(cc); 767 wakeup(&cc->cc_exec_entity[direct].cc_waiting); 768 CC_LOCK(cc); 769 } else if (cc_cce_migrating(cc, direct)) { 770 KASSERT((c_flags & CALLOUT_LOCAL_ALLOC) == 0, 771 ("Migrating legacy callout %p", c)); 772 #ifdef SMP 773 /* 774 * If the callout was scheduled for 775 * migration just perform it now. 776 */ 777 new_cpu = cc->cc_exec_entity[direct].ce_migration_cpu; 778 new_time = cc->cc_exec_entity[direct].ce_migration_time; 779 new_prec = cc->cc_exec_entity[direct].ce_migration_prec; 780 new_func = cc->cc_exec_entity[direct].ce_migration_func; 781 new_arg = cc->cc_exec_entity[direct].ce_migration_arg; 782 cc_cce_cleanup(cc, direct); 783 784 /* 785 * It should be assert here that the callout is not destroyed 786 * but that is not easy. 787 * 788 * As first thing, handle deferred callout stops. 789 */ 790 if ((c->c_flags & CALLOUT_DFRMIGRATION) == 0) { 791 CTR3(KTR_CALLOUT, 792 "deferred cancelled %p func %p arg %p", 793 c, new_func, new_arg); 794 callout_cc_del(c, cc); 795 return; 796 } 797 c->c_flags &= ~CALLOUT_DFRMIGRATION; 798 799 new_cc = callout_cpu_switch(c, cc, new_cpu); 800 flags = (direct) ? C_DIRECT_EXEC : 0; 801 callout_cc_add(c, new_cc, new_time, new_prec, new_func, 802 new_arg, new_cpu, flags); 803 CC_UNLOCK(new_cc); 804 CC_LOCK(cc); 805 #else 806 panic("migration should not happen"); 807 #endif 808 } 809 /* 810 * If the current callout is locally allocated (from 811 * timeout(9)) then put it on the freelist. 812 * 813 * Note: we need to check the cached copy of c_flags because 814 * if it was not local, then it's not safe to deref the 815 * callout pointer. 816 */ 817 KASSERT((c_flags & CALLOUT_LOCAL_ALLOC) == 0 || 818 c->c_flags == CALLOUT_LOCAL_ALLOC, 819 ("corrupted callout")); 820 if (c_flags & CALLOUT_LOCAL_ALLOC) 821 callout_cc_del(c, cc); 822 } 823 824 /* 825 * The callout mechanism is based on the work of Adam M. Costello and 826 * George Varghese, published in a technical report entitled "Redesigning 827 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 828 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 829 * used in this implementation was published by G. Varghese and T. Lauck in 830 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 831 * the Efficient Implementation of a Timer Facility" in the Proceedings of 832 * the 11th ACM Annual Symposium on Operating Systems Principles, 833 * Austin, Texas Nov 1987. 834 */ 835 836 /* 837 * Software (low priority) clock interrupt. 838 * Run periodic events from timeout queue. 839 */ 840 void 841 softclock(void *arg) 842 { 843 struct callout_cpu *cc; 844 struct callout *c; 845 #ifdef CALLOUT_PROFILING 846 int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0; 847 #endif 848 849 cc = (struct callout_cpu *)arg; 850 CC_LOCK(cc); 851 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { 852 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 853 softclock_call_cc(c, cc, 854 #ifdef CALLOUT_PROFILING 855 &mpcalls, &lockcalls, &gcalls, 856 #endif 857 0); 858 #ifdef CALLOUT_PROFILING 859 ++depth; 860 #endif 861 } 862 #ifdef CALLOUT_PROFILING 863 avg_depth += (depth * 1000 - avg_depth) >> 8; 864 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 865 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 866 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 867 #endif 868 CC_UNLOCK(cc); 869 } 870 871 /* 872 * timeout -- 873 * Execute a function after a specified length of time. 874 * 875 * untimeout -- 876 * Cancel previous timeout function call. 877 * 878 * callout_handle_init -- 879 * Initialize a handle so that using it with untimeout is benign. 880 * 881 * See AT&T BCI Driver Reference Manual for specification. This 882 * implementation differs from that one in that although an 883 * identification value is returned from timeout, the original 884 * arguments to timeout as well as the identifier are used to 885 * identify entries for untimeout. 886 */ 887 struct callout_handle 888 timeout(timeout_t *ftn, void *arg, int to_ticks) 889 { 890 struct callout_cpu *cc; 891 struct callout *new; 892 struct callout_handle handle; 893 894 cc = CC_CPU(timeout_cpu); 895 CC_LOCK(cc); 896 /* Fill in the next free callout structure. */ 897 new = SLIST_FIRST(&cc->cc_callfree); 898 if (new == NULL) 899 /* XXX Attempt to malloc first */ 900 panic("timeout table full"); 901 SLIST_REMOVE_HEAD(&cc->cc_callfree, c_links.sle); 902 callout_reset(new, to_ticks, ftn, arg); 903 handle.callout = new; 904 CC_UNLOCK(cc); 905 906 return (handle); 907 } 908 909 void 910 untimeout(timeout_t *ftn, void *arg, struct callout_handle handle) 911 { 912 struct callout_cpu *cc; 913 914 /* 915 * Check for a handle that was initialized 916 * by callout_handle_init, but never used 917 * for a real timeout. 918 */ 919 if (handle.callout == NULL) 920 return; 921 922 cc = callout_lock(handle.callout); 923 if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) 924 callout_stop(handle.callout); 925 CC_UNLOCK(cc); 926 } 927 928 void 929 callout_handle_init(struct callout_handle *handle) 930 { 931 handle->callout = NULL; 932 } 933 934 /* 935 * New interface; clients allocate their own callout structures. 936 * 937 * callout_reset() - establish or change a timeout 938 * callout_stop() - disestablish a timeout 939 * callout_init() - initialize a callout structure so that it can 940 * safely be passed to callout_reset() and callout_stop() 941 * 942 * <sys/callout.h> defines three convenience macros: 943 * 944 * callout_active() - returns truth if callout has not been stopped, 945 * drained, or deactivated since the last time the callout was 946 * reset. 947 * callout_pending() - returns truth if callout is still waiting for timeout 948 * callout_deactivate() - marks the callout as having been serviced 949 */ 950 int 951 callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t precision, 952 void (*ftn)(void *), void *arg, int cpu, int flags) 953 { 954 sbintime_t to_sbt, pr; 955 struct callout_cpu *cc; 956 int cancelled, direct; 957 958 cancelled = 0; 959 if (flags & C_ABSOLUTE) { 960 to_sbt = sbt; 961 } else { 962 if ((flags & C_HARDCLOCK) && (sbt < tick_sbt)) 963 sbt = tick_sbt; 964 if ((flags & C_HARDCLOCK) || 965 #ifdef NO_EVENTTIMERS 966 sbt >= sbt_timethreshold) { 967 to_sbt = getsbinuptime(); 968 969 /* Add safety belt for the case of hz > 1000. */ 970 to_sbt += tc_tick_sbt - tick_sbt; 971 #else 972 sbt >= sbt_tickthreshold) { 973 /* 974 * Obtain the time of the last hardclock() call on 975 * this CPU directly from the kern_clocksource.c. 976 * This value is per-CPU, but it is equal for all 977 * active ones. 978 */ 979 #ifdef __LP64__ 980 to_sbt = DPCPU_GET(hardclocktime); 981 #else 982 spinlock_enter(); 983 to_sbt = DPCPU_GET(hardclocktime); 984 spinlock_exit(); 985 #endif 986 #endif 987 if ((flags & C_HARDCLOCK) == 0) 988 to_sbt += tick_sbt; 989 } else 990 to_sbt = sbinuptime(); 991 if (SBT_MAX - to_sbt < sbt) 992 to_sbt = SBT_MAX; 993 else 994 to_sbt += sbt; 995 pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : 996 sbt >> C_PRELGET(flags)); 997 if (pr > precision) 998 precision = pr; 999 } 1000 /* 1001 * Don't allow migration of pre-allocated callouts lest they 1002 * become unbalanced. 1003 */ 1004 if (c->c_flags & CALLOUT_LOCAL_ALLOC) 1005 cpu = c->c_cpu; 1006 direct = (c->c_flags & CALLOUT_DIRECT) != 0; 1007 KASSERT(!direct || c->c_lock == NULL, 1008 ("%s: direct callout %p has lock", __func__, c)); 1009 cc = callout_lock(c); 1010 if (cc->cc_exec_entity[direct].cc_curr == c) { 1011 /* 1012 * We're being asked to reschedule a callout which is 1013 * currently in progress. If there is a lock then we 1014 * can cancel the callout if it has not really started. 1015 */ 1016 if (c->c_lock != NULL && !cc->cc_exec_entity[direct].cc_cancel) 1017 cancelled = cc->cc_exec_entity[direct].cc_cancel = true; 1018 if (cc->cc_exec_entity[direct].cc_waiting) { 1019 /* 1020 * Someone has called callout_drain to kill this 1021 * callout. Don't reschedule. 1022 */ 1023 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 1024 cancelled ? "cancelled" : "failed to cancel", 1025 c, c->c_func, c->c_arg); 1026 CC_UNLOCK(cc); 1027 return (cancelled); 1028 } 1029 } 1030 if (c->c_flags & CALLOUT_PENDING) { 1031 if ((c->c_flags & CALLOUT_PROCESSED) == 0) { 1032 if (cc->cc_exec_next_dir == c) 1033 cc->cc_exec_next_dir = LIST_NEXT(c, c_links.le); 1034 LIST_REMOVE(c, c_links.le); 1035 } else 1036 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1037 cancelled = 1; 1038 c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING); 1039 } 1040 1041 #ifdef SMP 1042 /* 1043 * If the callout must migrate try to perform it immediately. 1044 * If the callout is currently running, just defer the migration 1045 * to a more appropriate moment. 1046 */ 1047 if (c->c_cpu != cpu) { 1048 if (cc->cc_exec_entity[direct].cc_curr == c) { 1049 cc->cc_exec_entity[direct].ce_migration_cpu = cpu; 1050 cc->cc_exec_entity[direct].ce_migration_time 1051 = to_sbt; 1052 cc->cc_exec_entity[direct].ce_migration_prec 1053 = precision; 1054 cc->cc_exec_entity[direct].ce_migration_func = ftn; 1055 cc->cc_exec_entity[direct].ce_migration_arg = arg; 1056 c->c_flags |= CALLOUT_DFRMIGRATION; 1057 CTR6(KTR_CALLOUT, 1058 "migration of %p func %p arg %p in %d.%08x to %u deferred", 1059 c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1060 (u_int)(to_sbt & 0xffffffff), cpu); 1061 CC_UNLOCK(cc); 1062 return (cancelled); 1063 } 1064 cc = callout_cpu_switch(c, cc, cpu); 1065 } 1066 #endif 1067 1068 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags); 1069 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", 1070 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1071 (u_int)(to_sbt & 0xffffffff)); 1072 CC_UNLOCK(cc); 1073 1074 return (cancelled); 1075 } 1076 1077 /* 1078 * Common idioms that can be optimized in the future. 1079 */ 1080 int 1081 callout_schedule_on(struct callout *c, int to_ticks, int cpu) 1082 { 1083 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 1084 } 1085 1086 int 1087 callout_schedule(struct callout *c, int to_ticks) 1088 { 1089 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 1090 } 1091 1092 int 1093 _callout_stop_safe(struct callout *c, int safe) 1094 { 1095 struct callout_cpu *cc, *old_cc; 1096 struct lock_class *class; 1097 int direct, sq_locked, use_lock; 1098 1099 /* 1100 * Some old subsystems don't hold Giant while running a callout_stop(), 1101 * so just discard this check for the moment. 1102 */ 1103 if (!safe && c->c_lock != NULL) { 1104 if (c->c_lock == &Giant.lock_object) 1105 use_lock = mtx_owned(&Giant); 1106 else { 1107 use_lock = 1; 1108 class = LOCK_CLASS(c->c_lock); 1109 class->lc_assert(c->c_lock, LA_XLOCKED); 1110 } 1111 } else 1112 use_lock = 0; 1113 direct = (c->c_flags & CALLOUT_DIRECT) != 0; 1114 sq_locked = 0; 1115 old_cc = NULL; 1116 again: 1117 cc = callout_lock(c); 1118 1119 /* 1120 * If the callout was migrating while the callout cpu lock was 1121 * dropped, just drop the sleepqueue lock and check the states 1122 * again. 1123 */ 1124 if (sq_locked != 0 && cc != old_cc) { 1125 #ifdef SMP 1126 CC_UNLOCK(cc); 1127 sleepq_release(&old_cc->cc_exec_entity[direct].cc_waiting); 1128 sq_locked = 0; 1129 old_cc = NULL; 1130 goto again; 1131 #else 1132 panic("migration should not happen"); 1133 #endif 1134 } 1135 1136 /* 1137 * If the callout isn't pending, it's not on the queue, so 1138 * don't attempt to remove it from the queue. We can try to 1139 * stop it by other means however. 1140 */ 1141 if (!(c->c_flags & CALLOUT_PENDING)) { 1142 c->c_flags &= ~CALLOUT_ACTIVE; 1143 1144 /* 1145 * If it wasn't on the queue and it isn't the current 1146 * callout, then we can't stop it, so just bail. 1147 */ 1148 if (cc->cc_exec_entity[direct].cc_curr != c) { 1149 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1150 c, c->c_func, c->c_arg); 1151 CC_UNLOCK(cc); 1152 if (sq_locked) 1153 sleepq_release( 1154 &cc->cc_exec_entity[direct].cc_waiting); 1155 return (0); 1156 } 1157 1158 if (safe) { 1159 /* 1160 * The current callout is running (or just 1161 * about to run) and blocking is allowed, so 1162 * just wait for the current invocation to 1163 * finish. 1164 */ 1165 while (cc->cc_exec_entity[direct].cc_curr == c) { 1166 /* 1167 * Use direct calls to sleepqueue interface 1168 * instead of cv/msleep in order to avoid 1169 * a LOR between cc_lock and sleepqueue 1170 * chain spinlocks. This piece of code 1171 * emulates a msleep_spin() call actually. 1172 * 1173 * If we already have the sleepqueue chain 1174 * locked, then we can safely block. If we 1175 * don't already have it locked, however, 1176 * we have to drop the cc_lock to lock 1177 * it. This opens several races, so we 1178 * restart at the beginning once we have 1179 * both locks. If nothing has changed, then 1180 * we will end up back here with sq_locked 1181 * set. 1182 */ 1183 if (!sq_locked) { 1184 CC_UNLOCK(cc); 1185 sleepq_lock( 1186 &cc->cc_exec_entity[direct].cc_waiting); 1187 sq_locked = 1; 1188 old_cc = cc; 1189 goto again; 1190 } 1191 1192 /* 1193 * Migration could be cancelled here, but 1194 * as long as it is still not sure when it 1195 * will be packed up, just let softclock() 1196 * take care of it. 1197 */ 1198 cc->cc_exec_entity[direct].cc_waiting = true; 1199 DROP_GIANT(); 1200 CC_UNLOCK(cc); 1201 sleepq_add( 1202 &cc->cc_exec_entity[direct].cc_waiting, 1203 &cc->cc_lock.lock_object, "codrain", 1204 SLEEPQ_SLEEP, 0); 1205 sleepq_wait( 1206 &cc->cc_exec_entity[direct].cc_waiting, 1207 0); 1208 sq_locked = 0; 1209 old_cc = NULL; 1210 1211 /* Reacquire locks previously released. */ 1212 PICKUP_GIANT(); 1213 CC_LOCK(cc); 1214 } 1215 } else if (use_lock && 1216 !cc->cc_exec_entity[direct].cc_cancel) { 1217 /* 1218 * The current callout is waiting for its 1219 * lock which we hold. Cancel the callout 1220 * and return. After our caller drops the 1221 * lock, the callout will be skipped in 1222 * softclock(). 1223 */ 1224 cc->cc_exec_entity[direct].cc_cancel = true; 1225 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1226 c, c->c_func, c->c_arg); 1227 KASSERT(!cc_cce_migrating(cc, direct), 1228 ("callout wrongly scheduled for migration")); 1229 CC_UNLOCK(cc); 1230 KASSERT(!sq_locked, ("sleepqueue chain locked")); 1231 return (1); 1232 } else if ((c->c_flags & CALLOUT_DFRMIGRATION) != 0) { 1233 c->c_flags &= ~CALLOUT_DFRMIGRATION; 1234 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 1235 c, c->c_func, c->c_arg); 1236 CC_UNLOCK(cc); 1237 return (1); 1238 } 1239 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1240 c, c->c_func, c->c_arg); 1241 CC_UNLOCK(cc); 1242 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 1243 return (0); 1244 } 1245 if (sq_locked) 1246 sleepq_release(&cc->cc_exec_entity[direct].cc_waiting); 1247 1248 c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING); 1249 1250 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1251 c, c->c_func, c->c_arg); 1252 if ((c->c_flags & CALLOUT_PROCESSED) == 0) { 1253 if (cc->cc_exec_next_dir == c) 1254 cc->cc_exec_next_dir = LIST_NEXT(c, c_links.le); 1255 LIST_REMOVE(c, c_links.le); 1256 } else 1257 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1258 callout_cc_del(c, cc); 1259 1260 CC_UNLOCK(cc); 1261 return (1); 1262 } 1263 1264 void 1265 callout_init(struct callout *c, int mpsafe) 1266 { 1267 bzero(c, sizeof *c); 1268 if (mpsafe) { 1269 c->c_lock = NULL; 1270 c->c_flags = CALLOUT_RETURNUNLOCKED; 1271 } else { 1272 c->c_lock = &Giant.lock_object; 1273 c->c_flags = 0; 1274 } 1275 c->c_cpu = timeout_cpu; 1276 } 1277 1278 void 1279 _callout_init_lock(struct callout *c, struct lock_object *lock, int flags) 1280 { 1281 bzero(c, sizeof *c); 1282 c->c_lock = lock; 1283 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1284 ("callout_init_lock: bad flags %d", flags)); 1285 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1286 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1287 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & 1288 (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class", 1289 __func__)); 1290 c->c_flags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1291 c->c_cpu = timeout_cpu; 1292 } 1293 1294 #ifdef APM_FIXUP_CALLTODO 1295 /* 1296 * Adjust the kernel calltodo timeout list. This routine is used after 1297 * an APM resume to recalculate the calltodo timer list values with the 1298 * number of hz's we have been sleeping. The next hardclock() will detect 1299 * that there are fired timers and run softclock() to execute them. 1300 * 1301 * Please note, I have not done an exhaustive analysis of what code this 1302 * might break. I am motivated to have my select()'s and alarm()'s that 1303 * have expired during suspend firing upon resume so that the applications 1304 * which set the timer can do the maintanence the timer was for as close 1305 * as possible to the originally intended time. Testing this code for a 1306 * week showed that resuming from a suspend resulted in 22 to 25 timers 1307 * firing, which seemed independant on whether the suspend was 2 hours or 1308 * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu> 1309 */ 1310 void 1311 adjust_timeout_calltodo(struct timeval *time_change) 1312 { 1313 register struct callout *p; 1314 unsigned long delta_ticks; 1315 1316 /* 1317 * How many ticks were we asleep? 1318 * (stolen from tvtohz()). 1319 */ 1320 1321 /* Don't do anything */ 1322 if (time_change->tv_sec < 0) 1323 return; 1324 else if (time_change->tv_sec <= LONG_MAX / 1000000) 1325 delta_ticks = (time_change->tv_sec * 1000000 + 1326 time_change->tv_usec + (tick - 1)) / tick + 1; 1327 else if (time_change->tv_sec <= LONG_MAX / hz) 1328 delta_ticks = time_change->tv_sec * hz + 1329 (time_change->tv_usec + (tick - 1)) / tick + 1; 1330 else 1331 delta_ticks = LONG_MAX; 1332 1333 if (delta_ticks > INT_MAX) 1334 delta_ticks = INT_MAX; 1335 1336 /* 1337 * Now rip through the timer calltodo list looking for timers 1338 * to expire. 1339 */ 1340 1341 /* don't collide with softclock() */ 1342 CC_LOCK(cc); 1343 for (p = calltodo.c_next; p != NULL; p = p->c_next) { 1344 p->c_time -= delta_ticks; 1345 1346 /* Break if the timer had more time on it than delta_ticks */ 1347 if (p->c_time > 0) 1348 break; 1349 1350 /* take back the ticks the timer didn't use (p->c_time <= 0) */ 1351 delta_ticks = -p->c_time; 1352 } 1353 CC_UNLOCK(cc); 1354 1355 return; 1356 } 1357 #endif /* APM_FIXUP_CALLTODO */ 1358 1359 static int 1360 flssbt(sbintime_t sbt) 1361 { 1362 1363 sbt += (uint64_t)sbt >> 1; 1364 if (sizeof(long) >= sizeof(sbintime_t)) 1365 return (flsl(sbt)); 1366 if (sbt >= SBT_1S) 1367 return (flsl(((uint64_t)sbt) >> 32) + 32); 1368 return (flsl(sbt)); 1369 } 1370 1371 /* 1372 * Dump immediate statistic snapshot of the scheduled callouts. 1373 */ 1374 static int 1375 sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1376 { 1377 struct callout *tmp; 1378 struct callout_cpu *cc; 1379 struct callout_list *sc; 1380 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; 1381 int ct[64], cpr[64], ccpbk[32]; 1382 int error, val, i, count, tcum, pcum, maxc, c, medc; 1383 #ifdef SMP 1384 int cpu; 1385 #endif 1386 1387 val = 0; 1388 error = sysctl_handle_int(oidp, &val, 0, req); 1389 if (error != 0 || req->newptr == NULL) 1390 return (error); 1391 count = maxc = 0; 1392 st = spr = maxt = maxpr = 0; 1393 bzero(ccpbk, sizeof(ccpbk)); 1394 bzero(ct, sizeof(ct)); 1395 bzero(cpr, sizeof(cpr)); 1396 now = sbinuptime(); 1397 #ifdef SMP 1398 CPU_FOREACH(cpu) { 1399 cc = CC_CPU(cpu); 1400 #else 1401 cc = CC_CPU(timeout_cpu); 1402 #endif 1403 CC_LOCK(cc); 1404 for (i = 0; i < callwheelsize; i++) { 1405 sc = &cc->cc_callwheel[i]; 1406 c = 0; 1407 LIST_FOREACH(tmp, sc, c_links.le) { 1408 c++; 1409 t = tmp->c_time - now; 1410 if (t < 0) 1411 t = 0; 1412 st += t / SBT_1US; 1413 spr += tmp->c_precision / SBT_1US; 1414 if (t > maxt) 1415 maxt = t; 1416 if (tmp->c_precision > maxpr) 1417 maxpr = tmp->c_precision; 1418 ct[flssbt(t)]++; 1419 cpr[flssbt(tmp->c_precision)]++; 1420 } 1421 if (c > maxc) 1422 maxc = c; 1423 ccpbk[fls(c + c / 2)]++; 1424 count += c; 1425 } 1426 CC_UNLOCK(cc); 1427 #ifdef SMP 1428 } 1429 #endif 1430 1431 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1432 tcum += ct[i]; 1433 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1434 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) 1435 pcum += cpr[i]; 1436 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1437 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1438 c += ccpbk[i]; 1439 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1440 1441 printf("Scheduled callouts statistic snapshot:\n"); 1442 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1443 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1444 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1445 medc, 1446 count / callwheelsize / mp_ncpus, 1447 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1448 maxc); 1449 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1450 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1451 (st / count) / 1000000, (st / count) % 1000000, 1452 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); 1453 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1454 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, 1455 (spr / count) / 1000000, (spr / count) % 1000000, 1456 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); 1457 printf(" Distribution: \tbuckets\t time\t tcum\t" 1458 " prec\t pcum\n"); 1459 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1460 if (ct[i] == 0 && cpr[i] == 0) 1461 continue; 1462 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1463 tcum += ct[i]; 1464 pcum += cpr[i]; 1465 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", 1466 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1467 i - 1 - (32 - CC_HASH_SHIFT), 1468 ct[i], tcum, cpr[i], pcum); 1469 } 1470 return (error); 1471 } 1472 SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1473 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1474 0, 0, sysctl_kern_callout_stat, "I", 1475 "Dump immediate statistic snapshot of the scheduled callouts"); 1476