Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]
FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_timeout.c
Version:
- FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
SearchContext: - none - 3 - 10
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: releng/10.1/sys/kern/kern_timeout.c 260817 2014-01-17 10:58:59Z avg $"); 39 40 #include "opt_callout_profiling.h" 41 #include "opt_kdtrace.h" 42 #if defined(__arm__) 43 #include "opt_timer.h" 44 #endif 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, &ncallout, 0, 106 "Number of entries in callwheel and size of timeout() preallocation"); 107 108 /* 109 * TODO: 110 * allocate more timeout table slots when table overflows. 111 */ 112 u_int callwheelsize, callwheelmask; 113 114 /* 115 * The callout cpu exec entities represent informations necessary for 116 * describing the state of callouts currently running on the CPU and the ones 117 * necessary for migrating callouts to the new callout cpu. In particular, 118 * the first entry of the array cc_exec_entity holds informations for callout 119 * running in SWI thread context, while the second one holds informations 120 * for callout running directly from hardware interrupt context. 121 * The cached informations are very important for deferring migration when 122 * the migrating callout is already running. 123 */ 124 struct cc_exec { 125 struct callout *cc_next; 126 struct callout *cc_curr; 127 #ifdef SMP 128 void (*ce_migration_func)(void *); 129 void *ce_migration_arg; 130 int ce_migration_cpu; 131 sbintime_t ce_migration_time; 132 sbintime_t ce_migration_prec; 133 #endif 134 bool cc_cancel; 135 bool cc_waiting; 136 }; 137 138 /* 139 * There is one struct callout_cpu per cpu, holding all relevant 140 * state for the callout processing thread on the individual CPU. 141 */ 142 struct callout_cpu { 143 struct mtx_padalign cc_lock; 144 struct cc_exec cc_exec_entity[2]; 145 struct callout *cc_callout; 146 struct callout_list *cc_callwheel; 147 struct callout_tailq cc_expireq; 148 struct callout_slist cc_callfree; 149 sbintime_t cc_firstevent; 150 sbintime_t cc_lastscan; 151 void *cc_cookie; 152 u_int cc_bucket; 153 }; 154 155 #define cc_exec_curr cc_exec_entity[0].cc_curr 156 #define cc_exec_next cc_exec_entity[0].cc_next 157 #define cc_exec_cancel cc_exec_entity[0].cc_cancel 158 #define cc_exec_waiting cc_exec_entity[0].cc_waiting 159 #define cc_exec_curr_dir cc_exec_entity[1].cc_curr 160 #define cc_exec_next_dir cc_exec_entity[1].cc_next 161 #define cc_exec_cancel_dir cc_exec_entity[1].cc_cancel 162 #define cc_exec_waiting_dir cc_exec_entity[1].cc_waiting 163 164 #ifdef SMP 165 #define cc_migration_func cc_exec_entity[0].ce_migration_func 166 #define cc_migration_arg cc_exec_entity[0].ce_migration_arg 167 #define cc_migration_cpu cc_exec_entity[0].ce_migration_cpu 168 #define cc_migration_time cc_exec_entity[0].ce_migration_time 169 #define cc_migration_prec cc_exec_entity[0].ce_migration_prec 170 #define cc_migration_func_dir cc_exec_entity[1].ce_migration_func 171 #define cc_migration_arg_dir cc_exec_entity[1].ce_migration_arg 172 #define cc_migration_cpu_dir cc_exec_entity[1].ce_migration_cpu 173 #define cc_migration_time_dir cc_exec_entity[1].ce_migration_time 174 #define cc_migration_prec_dir cc_exec_entity[1].ce_migration_prec 175 176 struct callout_cpu cc_cpu[MAXCPU]; 177 #define CPUBLOCK MAXCPU 178 #define CC_CPU(cpu) (&cc_cpu[(cpu)]) 179 #define CC_SELF() CC_CPU(PCPU_GET(cpuid)) 180 #else 181 struct callout_cpu cc_cpu; 182 #define CC_CPU(cpu) &cc_cpu 183 #define CC_SELF() &cc_cpu 184 #endif 185 #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) 186 #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) 187 #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) 188 189 static int timeout_cpu; 190 191 static void callout_cpu_init(struct callout_cpu *cc); 192 static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, 193 #ifdef CALLOUT_PROFILING 194 int *mpcalls, int *lockcalls, int *gcalls, 195 #endif 196 int direct); 197 198 static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); 199 200 /** 201 * Locked by cc_lock: 202 * cc_curr - If a callout is in progress, it is cc_curr. 203 * If cc_curr is non-NULL, threads waiting in 204 * callout_drain() will be woken up as soon as the 205 * relevant callout completes. 206 * cc_cancel - Changing to 1 with both callout_lock and cc_lock held 207 * guarantees that the current callout will not run. 208 * The softclock() function sets this to 0 before it 209 * drops callout_lock to acquire c_lock, and it calls 210 * the handler only if curr_cancelled is still 0 after 211 * cc_lock is successfully acquired. 212 * cc_waiting - If a thread is waiting in callout_drain(), then 213 * callout_wait is nonzero. Set only when 214 * cc_curr is non-NULL. 215 */ 216 217 /* 218 * Resets the execution entity tied to a specific callout cpu. 219 */ 220 static void 221 cc_cce_cleanup(struct callout_cpu *cc, int direct) 222 { 223 224 cc->cc_exec_entity[direct].cc_curr = NULL; 225 cc->cc_exec_entity[direct].cc_next = NULL; 226 cc->cc_exec_entity[direct].cc_cancel = false; 227 cc->cc_exec_entity[direct].cc_waiting = false; 228 #ifdef SMP 229 cc->cc_exec_entity[direct].ce_migration_cpu = CPUBLOCK; 230 cc->cc_exec_entity[direct].ce_migration_time = 0; 231 cc->cc_exec_entity[direct].ce_migration_prec = 0; 232 cc->cc_exec_entity[direct].ce_migration_func = NULL; 233 cc->cc_exec_entity[direct].ce_migration_arg = NULL; 234 #endif 235 } 236 237 /* 238 * Checks if migration is requested by a specific callout cpu. 239 */ 240 static int 241 cc_cce_migrating(struct callout_cpu *cc, int direct) 242 { 243 244 #ifdef SMP 245 return (cc->cc_exec_entity[direct].ce_migration_cpu != CPUBLOCK); 246 #else 247 return (0); 248 #endif 249 } 250 251 /* 252 * Kernel low level callwheel initialization 253 * called on cpu0 during kernel startup. 254 */ 255 static void 256 callout_callwheel_init(void *dummy) 257 { 258 struct callout_cpu *cc; 259 260 /* 261 * Calculate the size of the callout wheel and the preallocated 262 * timeout() structures. 263 * XXX: Clip callout to result of previous function of maxusers 264 * maximum 384. This is still huge, but acceptable. 265 */ 266 ncallout = imin(16 + maxproc + maxfiles, 18508); 267 TUNABLE_INT_FETCH("kern.ncallout", &ncallout); 268 269 /* 270 * Calculate callout wheel size, should be next power of two higher 271 * than 'ncallout'. 272 */ 273 callwheelsize = 1 << fls(ncallout); 274 callwheelmask = callwheelsize - 1; 275 276 /* 277 * Only cpu0 handles timeout(9) and receives a preallocation. 278 * 279 * XXX: Once all timeout(9) consumers are converted this can 280 * be removed. 281 */ 282 timeout_cpu = PCPU_GET(cpuid); 283 cc = CC_CPU(timeout_cpu); 284 cc->cc_callout = malloc(ncallout * sizeof(struct callout), 285 M_CALLOUT, M_WAITOK); 286 callout_cpu_init(cc); 287 } 288 SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); 289 290 /* 291 * Initialize the per-cpu callout structures. 292 */ 293 static void 294 callout_cpu_init(struct callout_cpu *cc) 295 { 296 struct callout *c; 297 int i; 298 299 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); 300 SLIST_INIT(&cc->cc_callfree); 301 cc->cc_callwheel = malloc(sizeof(struct callout_list) * callwheelsize, 302 M_CALLOUT, M_WAITOK); 303 for (i = 0; i < callwheelsize; i++) 304 LIST_INIT(&cc->cc_callwheel[i]); 305 TAILQ_INIT(&cc->cc_expireq); 306 cc->cc_firstevent = INT64_MAX; 307 for (i = 0; i < 2; i++) 308 cc_cce_cleanup(cc, i); 309 if (cc->cc_callout == NULL) /* Only cpu0 handles timeout(9) */ 310 return; 311 for (i = 0; i < ncallout; i++) { 312 c = &cc->cc_callout[i]; 313 callout_init(c, 0); 314 c->c_flags = CALLOUT_LOCAL_ALLOC; 315 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 316 } 317 } 318 319 #ifdef SMP 320 /* 321 * Switches the cpu tied to a specific callout. 322 * The function expects a locked incoming callout cpu and returns with 323 * locked outcoming callout cpu. 324 */ 325 static struct callout_cpu * 326 callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu) 327 { 328 struct callout_cpu *new_cc; 329 330 MPASS(c != NULL && cc != NULL); 331 CC_LOCK_ASSERT(cc); 332 333 /* 334 * Avoid interrupts and preemption firing after the callout cpu 335 * is blocked in order to avoid deadlocks as the new thread 336 * may be willing to acquire the callout cpu lock. 337 */ 338 c->c_cpu = CPUBLOCK; 339 spinlock_enter(); 340 CC_UNLOCK(cc); 341 new_cc = CC_CPU(new_cpu); 342 CC_LOCK(new_cc); 343 spinlock_exit(); 344 c->c_cpu = new_cpu; 345 return (new_cc); 346 } 347 #endif 348 349 /* 350 * Start standard softclock thread. 351 */ 352 static void 353 start_softclock(void *dummy) 354 { 355 struct callout_cpu *cc; 356 #ifdef SMP 357 int cpu; 358 #endif 359 360 cc = CC_CPU(timeout_cpu); 361 if (swi_add(&clk_intr_event, "clock", softclock, cc, SWI_CLOCK, 362 INTR_MPSAFE, &cc->cc_cookie)) 363 panic("died while creating standard software ithreads"); 364 #ifdef SMP 365 CPU_FOREACH(cpu) { 366 if (cpu == timeout_cpu) 367 continue; 368 cc = CC_CPU(cpu); 369 cc->cc_callout = NULL; /* Only cpu0 handles timeout(9). */ 370 callout_cpu_init(cc); 371 if (swi_add(NULL, "clock", softclock, cc, SWI_CLOCK, 372 INTR_MPSAFE, &cc->cc_cookie)) 373 panic("died while creating standard software ithreads"); 374 } 375 #endif 376 } 377 SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); 378 379 #define CC_HASH_SHIFT 8 380 381 static inline u_int 382 callout_hash(sbintime_t sbt) 383 { 384 385 return (sbt >> (32 - CC_HASH_SHIFT)); 386 } 387 388 static inline u_int 389 callout_get_bucket(sbintime_t sbt) 390 { 391 392 return (callout_hash(sbt) & callwheelmask); 393 } 394 395 void 396 callout_process(sbintime_t now) 397 { 398 struct callout *tmp, *tmpn; 399 struct callout_cpu *cc; 400 struct callout_list *sc; 401 sbintime_t first, last, max, tmp_max; 402 uint32_t lookahead; 403 u_int firstb, lastb, nowb; 404 #ifdef CALLOUT_PROFILING 405 int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0; 406 #endif 407 408 cc = CC_SELF(); 409 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET); 410 411 /* Compute the buckets of the last scan and present times. */ 412 firstb = callout_hash(cc->cc_lastscan); 413 cc->cc_lastscan = now; 414 nowb = callout_hash(now); 415 416 /* Compute the last bucket and minimum time of the bucket after it. */ 417 if (nowb == firstb) 418 lookahead = (SBT_1S / 16); 419 else if (nowb - firstb == 1) 420 lookahead = (SBT_1S / 8); 421 else 422 lookahead = (SBT_1S / 2); 423 first = last = now; 424 first += (lookahead / 2); 425 last += lookahead; 426 last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); 427 lastb = callout_hash(last) - 1; 428 max = last; 429 430 /* 431 * Check if we wrapped around the entire wheel from the last scan. 432 * In case, we need to scan entirely the wheel for pending callouts. 433 */ 434 if (lastb - firstb >= callwheelsize) { 435 lastb = firstb + callwheelsize - 1; 436 if (nowb - firstb >= callwheelsize) 437 nowb = lastb; 438 } 439 440 /* Iterate callwheel from firstb to nowb and then up to lastb. */ 441 do { 442 sc = &cc->cc_callwheel[firstb & callwheelmask]; 443 tmp = LIST_FIRST(sc); 444 while (tmp != NULL) { 445 /* Run the callout if present time within allowed. */ 446 if (tmp->c_time <= now) { 447 /* 448 * Consumer told us the callout may be run 449 * directly from hardware interrupt context. 450 */ 451 if (tmp->c_flags & CALLOUT_DIRECT) { 452 #ifdef CALLOUT_PROFILING 453 ++depth_dir; 454 #endif 455 cc->cc_exec_next_dir = 456 LIST_NEXT(tmp, c_links.le); 457 cc->cc_bucket = firstb & callwheelmask; 458 LIST_REMOVE(tmp, c_links.le); 459 softclock_call_cc(tmp, cc, 460 #ifdef CALLOUT_PROFILING 461 &mpcalls_dir, &lockcalls_dir, NULL, 462 #endif 463 1); 464 tmp = cc->cc_exec_next_dir; 465 } else { 466 tmpn = LIST_NEXT(tmp, c_links.le); 467 LIST_REMOVE(tmp, c_links.le); 468 TAILQ_INSERT_TAIL(&cc->cc_expireq, 469 tmp, c_links.tqe); 470 tmp->c_flags |= CALLOUT_PROCESSED; 471 tmp = tmpn; 472 } 473 continue; 474 } 475 /* Skip events from distant future. */ 476 if (tmp->c_time >= max) 477 goto next; 478 /* 479 * Event minimal time is bigger than present maximal 480 * time, so it cannot be aggregated. 481 */ 482 if (tmp->c_time > last) { 483 lastb = nowb; 484 goto next; 485 } 486 /* Update first and last time, respecting this event. */ 487 if (tmp->c_time < first) 488 first = tmp->c_time; 489 tmp_max = tmp->c_time + tmp->c_precision; 490 if (tmp_max < last) 491 last = tmp_max; 492 next: 493 tmp = LIST_NEXT(tmp, c_links.le); 494 } 495 /* Proceed with the next bucket. */ 496 firstb++; 497 /* 498 * Stop if we looked after present time and found 499 * some event we can't execute at now. 500 * Stop if we looked far enough into the future. 501 */ 502 } while (((int)(firstb - lastb)) <= 0); 503 cc->cc_firstevent = last; 504 #ifndef NO_EVENTTIMERS 505 cpu_new_callout(curcpu, last, first); 506 #endif 507 #ifdef CALLOUT_PROFILING 508 avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8; 509 avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8; 510 avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8; 511 #endif 512 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 513 /* 514 * swi_sched acquires the thread lock, so we don't want to call it 515 * with cc_lock held; incorrect locking order. 516 */ 517 if (!TAILQ_EMPTY(&cc->cc_expireq)) 518 swi_sched(cc->cc_cookie, 0); 519 } 520 521 static struct callout_cpu * 522 callout_lock(struct callout *c) 523 { 524 struct callout_cpu *cc; 525 int cpu; 526 527 for (;;) { 528 cpu = c->c_cpu; 529 #ifdef SMP 530 if (cpu == CPUBLOCK) { 531 while (c->c_cpu == CPUBLOCK) 532 cpu_spinwait(); 533 continue; 534 } 535 #endif 536 cc = CC_CPU(cpu); 537 CC_LOCK(cc); 538 if (cpu == c->c_cpu) 539 break; 540 CC_UNLOCK(cc); 541 } 542 return (cc); 543 } 544 545 static void 546 callout_cc_add(struct callout *c, struct callout_cpu *cc, 547 sbintime_t sbt, sbintime_t precision, void (*func)(void *), 548 void *arg, int cpu, int flags) 549 { 550 int bucket; 551 552 CC_LOCK_ASSERT(cc); 553 if (sbt < cc->cc_lastscan) 554 sbt = cc->cc_lastscan; 555 c->c_arg = arg; 556 c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING); 557 if (flags & C_DIRECT_EXEC) 558 c->c_flags |= CALLOUT_DIRECT; 559 c->c_flags &= ~CALLOUT_PROCESSED; 560 c->c_func = func; 561 c->c_time = sbt; 562 c->c_precision = precision; 563 bucket = callout_get_bucket(c->c_time); 564 CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x", 565 c, (int)(c->c_precision >> 32), 566 (u_int)(c->c_precision & 0xffffffff)); 567 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); 568 if (cc->cc_bucket == bucket) 569 cc->cc_exec_next_dir = c; 570 #ifndef NO_EVENTTIMERS 571 /* 572 * Inform the eventtimers(4) subsystem there's a new callout 573 * that has been inserted, but only if really required. 574 */ 575 if (INT64_MAX - c->c_time < c->c_precision) 576 c->c_precision = INT64_MAX - c->c_time; 577 sbt = c->c_time + c->c_precision; 578 if (sbt < cc->cc_firstevent) { 579 cc->cc_firstevent = sbt; 580 cpu_new_callout(cpu, sbt, c->c_time); 581 } 582 #endif 583 } 584 585 static void 586 callout_cc_del(struct callout *c, struct callout_cpu *cc) 587 { 588 589 if ((c->c_flags & CALLOUT_LOCAL_ALLOC) == 0) 590 return; 591 c->c_func = NULL; 592 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 593 } 594 595 static void 596 softclock_call_cc(struct callout *c, struct callout_cpu *cc, 597 #ifdef CALLOUT_PROFILING 598 int *mpcalls, int *lockcalls, int *gcalls, 599 #endif 600 int direct) 601 { 602 struct rm_priotracker tracker; 603 void (*c_func)(void *); 604 void *c_arg; 605 struct lock_class *class; 606 struct lock_object *c_lock; 607 uintptr_t lock_status; 608 int c_flags; 609 #ifdef SMP 610 struct callout_cpu *new_cc; 611 void (*new_func)(void *); 612 void *new_arg; 613 int flags, new_cpu; 614 sbintime_t new_prec, new_time; 615 #endif 616 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 617 sbintime_t sbt1, sbt2; 618 struct timespec ts2; 619 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 620 static timeout_t *lastfunc; 621 #endif 622 623 KASSERT((c->c_flags & (CALLOUT_PENDING | CALLOUT_ACTIVE)) == 624 (CALLOUT_PENDING | CALLOUT_ACTIVE), 625 ("softclock_call_cc: pend|act %p %x", c, c->c_flags)); 626 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; 627 lock_status = 0; 628 if (c->c_flags & CALLOUT_SHAREDLOCK) { 629 if (class == &lock_class_rm) 630 lock_status = (uintptr_t)&tracker; 631 else 632 lock_status = 1; 633 } 634 c_lock = c->c_lock; 635 c_func = c->c_func; 636 c_arg = c->c_arg; 637 c_flags = c->c_flags; 638 if (c->c_flags & CALLOUT_LOCAL_ALLOC) 639 c->c_flags = CALLOUT_LOCAL_ALLOC; 640 else 641 c->c_flags &= ~CALLOUT_PENDING; 642 cc->cc_exec_entity[direct].cc_curr = c; 643 cc->cc_exec_entity[direct].cc_cancel = false; 644 CC_UNLOCK(cc); 645 if (c_lock != NULL) { 646 class->lc_lock(c_lock, lock_status); 647 /* 648 * The callout may have been cancelled 649 * while we switched locks. 650 */ 651 if (cc->cc_exec_entity[direct].cc_cancel) { 652 class->lc_unlock(c_lock); 653 goto skip; 654 } 655 /* The callout cannot be stopped now. */ 656 cc->cc_exec_entity[direct].cc_cancel = true; 657 if (c_lock == &Giant.lock_object) { 658 #ifdef CALLOUT_PROFILING 659 (*gcalls)++; 660 #endif 661 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", 662 c, c_func, c_arg); 663 } else { 664 #ifdef CALLOUT_PROFILING 665 (*lockcalls)++; 666 #endif 667 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", 668 c, c_func, c_arg); 669 } 670 } else { 671 #ifdef CALLOUT_PROFILING 672 (*mpcalls)++; 673 #endif 674 CTR3(KTR_CALLOUT, "callout %p func %p arg %p", 675 c, c_func, c_arg); 676 } 677 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 678 sbt1 = sbinuptime(); 679 #endif 680 THREAD_NO_SLEEPING(); 681 SDT_PROBE(callout_execute, kernel, , callout__start, c, 0, 0, 0, 0); 682 c_func(c_arg); 683 SDT_PROBE(callout_execute, kernel, , callout__end, c, 0, 0, 0, 0); 684 THREAD_SLEEPING_OK(); 685 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 686 sbt2 = sbinuptime(); 687 sbt2 -= sbt1; 688 if (sbt2 > maxdt) { 689 if (lastfunc != c_func || sbt2 > maxdt * 2) { 690 ts2 = sbttots(sbt2); 691 printf( 692 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 693 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); 694 } 695 maxdt = sbt2; 696 lastfunc = c_func; 697 } 698 #endif 699 CTR1(KTR_CALLOUT, "callout %p finished", c); 700 if ((c_flags & CALLOUT_RETURNUNLOCKED) == 0) 701 class->lc_unlock(c_lock); 702 skip: 703 CC_LOCK(cc); 704 KASSERT(cc->cc_exec_entity[direct].cc_curr == c, ("mishandled cc_curr")); 705 cc->cc_exec_entity[direct].cc_curr = NULL; 706 if (cc->cc_exec_entity[direct].cc_waiting) { 707 /* 708 * There is someone waiting for the 709 * callout to complete. 710 * If the callout was scheduled for 711 * migration just cancel it. 712 */ 713 if (cc_cce_migrating(cc, direct)) { 714 cc_cce_cleanup(cc, direct); 715 716 /* 717 * It should be assert here that the callout is not 718 * destroyed but that is not easy. 719 */ 720 c->c_flags &= ~CALLOUT_DFRMIGRATION; 721 } 722 cc->cc_exec_entity[direct].cc_waiting = false; 723 CC_UNLOCK(cc); 724 wakeup(&cc->cc_exec_entity[direct].cc_waiting); 725 CC_LOCK(cc); 726 } else if (cc_cce_migrating(cc, direct)) { 727 KASSERT((c_flags & CALLOUT_LOCAL_ALLOC) == 0, 728 ("Migrating legacy callout %p", c)); 729 #ifdef SMP 730 /* 731 * If the callout was scheduled for 732 * migration just perform it now. 733 */ 734 new_cpu = cc->cc_exec_entity[direct].ce_migration_cpu; 735 new_time = cc->cc_exec_entity[direct].ce_migration_time; 736 new_prec = cc->cc_exec_entity[direct].ce_migration_prec; 737 new_func = cc->cc_exec_entity[direct].ce_migration_func; 738 new_arg = cc->cc_exec_entity[direct].ce_migration_arg; 739 cc_cce_cleanup(cc, direct); 740 741 /* 742 * It should be assert here that the callout is not destroyed 743 * but that is not easy. 744 * 745 * As first thing, handle deferred callout stops. 746 */ 747 if ((c->c_flags & CALLOUT_DFRMIGRATION) == 0) { 748 CTR3(KTR_CALLOUT, 749 "deferred cancelled %p func %p arg %p", 750 c, new_func, new_arg); 751 callout_cc_del(c, cc); 752 return; 753 } 754 c->c_flags &= ~CALLOUT_DFRMIGRATION; 755 756 new_cc = callout_cpu_switch(c, cc, new_cpu); 757 flags = (direct) ? C_DIRECT_EXEC : 0; 758 callout_cc_add(c, new_cc, new_time, new_prec, new_func, 759 new_arg, new_cpu, flags); 760 CC_UNLOCK(new_cc); 761 CC_LOCK(cc); 762 #else 763 panic("migration should not happen"); 764 #endif 765 } 766 /* 767 * If the current callout is locally allocated (from 768 * timeout(9)) then put it on the freelist. 769 * 770 * Note: we need to check the cached copy of c_flags because 771 * if it was not local, then it's not safe to deref the 772 * callout pointer. 773 */ 774 KASSERT((c_flags & CALLOUT_LOCAL_ALLOC) == 0 || 775 c->c_flags == CALLOUT_LOCAL_ALLOC, 776 ("corrupted callout")); 777 if (c_flags & CALLOUT_LOCAL_ALLOC) 778 callout_cc_del(c, cc); 779 } 780 781 /* 782 * The callout mechanism is based on the work of Adam M. Costello and 783 * George Varghese, published in a technical report entitled "Redesigning 784 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 785 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 786 * used in this implementation was published by G. Varghese and T. Lauck in 787 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 788 * the Efficient Implementation of a Timer Facility" in the Proceedings of 789 * the 11th ACM Annual Symposium on Operating Systems Principles, 790 * Austin, Texas Nov 1987. 791 */ 792 793 /* 794 * Software (low priority) clock interrupt. 795 * Run periodic events from timeout queue. 796 */ 797 void 798 softclock(void *arg) 799 { 800 struct callout_cpu *cc; 801 struct callout *c; 802 #ifdef CALLOUT_PROFILING 803 int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0; 804 #endif 805 806 cc = (struct callout_cpu *)arg; 807 CC_LOCK(cc); 808 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { 809 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 810 softclock_call_cc(c, cc, 811 #ifdef CALLOUT_PROFILING 812 &mpcalls, &lockcalls, &gcalls, 813 #endif 814 0); 815 #ifdef CALLOUT_PROFILING 816 ++depth; 817 #endif 818 } 819 #ifdef CALLOUT_PROFILING 820 avg_depth += (depth * 1000 - avg_depth) >> 8; 821 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 822 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 823 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 824 #endif 825 CC_UNLOCK(cc); 826 } 827 828 /* 829 * timeout -- 830 * Execute a function after a specified length of time. 831 * 832 * untimeout -- 833 * Cancel previous timeout function call. 834 * 835 * callout_handle_init -- 836 * Initialize a handle so that using it with untimeout is benign. 837 * 838 * See AT&T BCI Driver Reference Manual for specification. This 839 * implementation differs from that one in that although an 840 * identification value is returned from timeout, the original 841 * arguments to timeout as well as the identifier are used to 842 * identify entries for untimeout. 843 */ 844 struct callout_handle 845 timeout(ftn, arg, to_ticks) 846 timeout_t *ftn; 847 void *arg; 848 int to_ticks; 849 { 850 struct callout_cpu *cc; 851 struct callout *new; 852 struct callout_handle handle; 853 854 cc = CC_CPU(timeout_cpu); 855 CC_LOCK(cc); 856 /* Fill in the next free callout structure. */ 857 new = SLIST_FIRST(&cc->cc_callfree); 858 if (new == NULL) 859 /* XXX Attempt to malloc first */ 860 panic("timeout table full"); 861 SLIST_REMOVE_HEAD(&cc->cc_callfree, c_links.sle); 862 callout_reset(new, to_ticks, ftn, arg); 863 handle.callout = new; 864 CC_UNLOCK(cc); 865 866 return (handle); 867 } 868 869 void 870 untimeout(ftn, arg, handle) 871 timeout_t *ftn; 872 void *arg; 873 struct callout_handle handle; 874 { 875 struct callout_cpu *cc; 876 877 /* 878 * Check for a handle that was initialized 879 * by callout_handle_init, but never used 880 * for a real timeout. 881 */ 882 if (handle.callout == NULL) 883 return; 884 885 cc = callout_lock(handle.callout); 886 if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) 887 callout_stop(handle.callout); 888 CC_UNLOCK(cc); 889 } 890 891 void 892 callout_handle_init(struct callout_handle *handle) 893 { 894 handle->callout = NULL; 895 } 896 897 /* 898 * New interface; clients allocate their own callout structures. 899 * 900 * callout_reset() - establish or change a timeout 901 * callout_stop() - disestablish a timeout 902 * callout_init() - initialize a callout structure so that it can 903 * safely be passed to callout_reset() and callout_stop() 904 * 905 * <sys/callout.h> defines three convenience macros: 906 * 907 * callout_active() - returns truth if callout has not been stopped, 908 * drained, or deactivated since the last time the callout was 909 * reset. 910 * callout_pending() - returns truth if callout is still waiting for timeout 911 * callout_deactivate() - marks the callout as having been serviced 912 */ 913 int 914 callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t precision, 915 void (*ftn)(void *), void *arg, int cpu, int flags) 916 { 917 sbintime_t to_sbt, pr; 918 struct callout_cpu *cc; 919 int cancelled, direct; 920 921 cancelled = 0; 922 if (flags & C_ABSOLUTE) { 923 to_sbt = sbt; 924 } else { 925 if ((flags & C_HARDCLOCK) && (sbt < tick_sbt)) 926 sbt = tick_sbt; 927 if ((flags & C_HARDCLOCK) || 928 #ifdef NO_EVENTTIMERS 929 sbt >= sbt_timethreshold) { 930 to_sbt = getsbinuptime(); 931 932 /* Add safety belt for the case of hz > 1000. */ 933 to_sbt += tc_tick_sbt - tick_sbt; 934 #else 935 sbt >= sbt_tickthreshold) { 936 /* 937 * Obtain the time of the last hardclock() call on 938 * this CPU directly from the kern_clocksource.c. 939 * This value is per-CPU, but it is equal for all 940 * active ones. 941 */ 942 #ifdef __LP64__ 943 to_sbt = DPCPU_GET(hardclocktime); 944 #else 945 spinlock_enter(); 946 to_sbt = DPCPU_GET(hardclocktime); 947 spinlock_exit(); 948 #endif 949 #endif 950 if ((flags & C_HARDCLOCK) == 0) 951 to_sbt += tick_sbt; 952 } else 953 to_sbt = sbinuptime(); 954 if (INT64_MAX - to_sbt < sbt) 955 to_sbt = INT64_MAX; 956 else 957 to_sbt += sbt; 958 pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : 959 sbt >> C_PRELGET(flags)); 960 if (pr > precision) 961 precision = pr; 962 } 963 /* 964 * Don't allow migration of pre-allocated callouts lest they 965 * become unbalanced. 966 */ 967 if (c->c_flags & CALLOUT_LOCAL_ALLOC) 968 cpu = c->c_cpu; 969 direct = (c->c_flags & CALLOUT_DIRECT) != 0; 970 KASSERT(!direct || c->c_lock == NULL, 971 ("%s: direct callout %p has lock", __func__, c)); 972 cc = callout_lock(c); 973 if (cc->cc_exec_entity[direct].cc_curr == c) { 974 /* 975 * We're being asked to reschedule a callout which is 976 * currently in progress. If there is a lock then we 977 * can cancel the callout if it has not really started. 978 */ 979 if (c->c_lock != NULL && !cc->cc_exec_entity[direct].cc_cancel) 980 cancelled = cc->cc_exec_entity[direct].cc_cancel = true; 981 if (cc->cc_exec_entity[direct].cc_waiting) { 982 /* 983 * Someone has called callout_drain to kill this 984 * callout. Don't reschedule. 985 */ 986 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 987 cancelled ? "cancelled" : "failed to cancel", 988 c, c->c_func, c->c_arg); 989 CC_UNLOCK(cc); 990 return (cancelled); 991 } 992 } 993 if (c->c_flags & CALLOUT_PENDING) { 994 if ((c->c_flags & CALLOUT_PROCESSED) == 0) { 995 if (cc->cc_exec_next_dir == c) 996 cc->cc_exec_next_dir = LIST_NEXT(c, c_links.le); 997 LIST_REMOVE(c, c_links.le); 998 } else 999 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1000 cancelled = 1; 1001 c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING); 1002 } 1003 1004 #ifdef SMP 1005 /* 1006 * If the callout must migrate try to perform it immediately. 1007 * If the callout is currently running, just defer the migration 1008 * to a more appropriate moment. 1009 */ 1010 if (c->c_cpu != cpu) { 1011 if (cc->cc_exec_entity[direct].cc_curr == c) { 1012 cc->cc_exec_entity[direct].ce_migration_cpu = cpu; 1013 cc->cc_exec_entity[direct].ce_migration_time 1014 = to_sbt; 1015 cc->cc_exec_entity[direct].ce_migration_prec 1016 = precision; 1017 cc->cc_exec_entity[direct].ce_migration_func = ftn; 1018 cc->cc_exec_entity[direct].ce_migration_arg = arg; 1019 c->c_flags |= CALLOUT_DFRMIGRATION; 1020 CTR6(KTR_CALLOUT, 1021 "migration of %p func %p arg %p in %d.%08x to %u deferred", 1022 c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1023 (u_int)(to_sbt & 0xffffffff), cpu); 1024 CC_UNLOCK(cc); 1025 return (cancelled); 1026 } 1027 cc = callout_cpu_switch(c, cc, cpu); 1028 } 1029 #endif 1030 1031 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags); 1032 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", 1033 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1034 (u_int)(to_sbt & 0xffffffff)); 1035 CC_UNLOCK(cc); 1036 1037 return (cancelled); 1038 } 1039 1040 /* 1041 * Common idioms that can be optimized in the future. 1042 */ 1043 int 1044 callout_schedule_on(struct callout *c, int to_ticks, int cpu) 1045 { 1046 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 1047 } 1048 1049 int 1050 callout_schedule(struct callout *c, int to_ticks) 1051 { 1052 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 1053 } 1054 1055 int 1056 _callout_stop_safe(c, safe) 1057 struct callout *c; 1058 int safe; 1059 { 1060 struct callout_cpu *cc, *old_cc; 1061 struct lock_class *class; 1062 int direct, sq_locked, use_lock; 1063 1064 /* 1065 * Some old subsystems don't hold Giant while running a callout_stop(), 1066 * so just discard this check for the moment. 1067 */ 1068 if (!safe && c->c_lock != NULL) { 1069 if (c->c_lock == &Giant.lock_object) 1070 use_lock = mtx_owned(&Giant); 1071 else { 1072 use_lock = 1; 1073 class = LOCK_CLASS(c->c_lock); 1074 class->lc_assert(c->c_lock, LA_XLOCKED); 1075 } 1076 } else 1077 use_lock = 0; 1078 direct = (c->c_flags & CALLOUT_DIRECT) != 0; 1079 sq_locked = 0; 1080 old_cc = NULL; 1081 again: 1082 cc = callout_lock(c); 1083 1084 /* 1085 * If the callout was migrating while the callout cpu lock was 1086 * dropped, just drop the sleepqueue lock and check the states 1087 * again. 1088 */ 1089 if (sq_locked != 0 && cc != old_cc) { 1090 #ifdef SMP 1091 CC_UNLOCK(cc); 1092 sleepq_release(&old_cc->cc_exec_entity[direct].cc_waiting); 1093 sq_locked = 0; 1094 old_cc = NULL; 1095 goto again; 1096 #else 1097 panic("migration should not happen"); 1098 #endif 1099 } 1100 1101 /* 1102 * If the callout isn't pending, it's not on the queue, so 1103 * don't attempt to remove it from the queue. We can try to 1104 * stop it by other means however. 1105 */ 1106 if (!(c->c_flags & CALLOUT_PENDING)) { 1107 c->c_flags &= ~CALLOUT_ACTIVE; 1108 1109 /* 1110 * If it wasn't on the queue and it isn't the current 1111 * callout, then we can't stop it, so just bail. 1112 */ 1113 if (cc->cc_exec_entity[direct].cc_curr != c) { 1114 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1115 c, c->c_func, c->c_arg); 1116 CC_UNLOCK(cc); 1117 if (sq_locked) 1118 sleepq_release( 1119 &cc->cc_exec_entity[direct].cc_waiting); 1120 return (0); 1121 } 1122 1123 if (safe) { 1124 /* 1125 * The current callout is running (or just 1126 * about to run) and blocking is allowed, so 1127 * just wait for the current invocation to 1128 * finish. 1129 */ 1130 while (cc->cc_exec_entity[direct].cc_curr == c) { 1131 /* 1132 * Use direct calls to sleepqueue interface 1133 * instead of cv/msleep in order to avoid 1134 * a LOR between cc_lock and sleepqueue 1135 * chain spinlocks. This piece of code 1136 * emulates a msleep_spin() call actually. 1137 * 1138 * If we already have the sleepqueue chain 1139 * locked, then we can safely block. If we 1140 * don't already have it locked, however, 1141 * we have to drop the cc_lock to lock 1142 * it. This opens several races, so we 1143 * restart at the beginning once we have 1144 * both locks. If nothing has changed, then 1145 * we will end up back here with sq_locked 1146 * set. 1147 */ 1148 if (!sq_locked) { 1149 CC_UNLOCK(cc); 1150 sleepq_lock( 1151 &cc->cc_exec_entity[direct].cc_waiting); 1152 sq_locked = 1; 1153 old_cc = cc; 1154 goto again; 1155 } 1156 1157 /* 1158 * Migration could be cancelled here, but 1159 * as long as it is still not sure when it 1160 * will be packed up, just let softclock() 1161 * take care of it. 1162 */ 1163 cc->cc_exec_entity[direct].cc_waiting = true; 1164 DROP_GIANT(); 1165 CC_UNLOCK(cc); 1166 sleepq_add( 1167 &cc->cc_exec_entity[direct].cc_waiting, 1168 &cc->cc_lock.lock_object, "codrain", 1169 SLEEPQ_SLEEP, 0); 1170 sleepq_wait( 1171 &cc->cc_exec_entity[direct].cc_waiting, 1172 0); 1173 sq_locked = 0; 1174 old_cc = NULL; 1175 1176 /* Reacquire locks previously released. */ 1177 PICKUP_GIANT(); 1178 CC_LOCK(cc); 1179 } 1180 } else if (use_lock && 1181 !cc->cc_exec_entity[direct].cc_cancel) { 1182 /* 1183 * The current callout is waiting for its 1184 * lock which we hold. Cancel the callout 1185 * and return. After our caller drops the 1186 * lock, the callout will be skipped in 1187 * softclock(). 1188 */ 1189 cc->cc_exec_entity[direct].cc_cancel = true; 1190 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1191 c, c->c_func, c->c_arg); 1192 KASSERT(!cc_cce_migrating(cc, direct), 1193 ("callout wrongly scheduled for migration")); 1194 CC_UNLOCK(cc); 1195 KASSERT(!sq_locked, ("sleepqueue chain locked")); 1196 return (1); 1197 } else if ((c->c_flags & CALLOUT_DFRMIGRATION) != 0) { 1198 c->c_flags &= ~CALLOUT_DFRMIGRATION; 1199 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 1200 c, c->c_func, c->c_arg); 1201 CC_UNLOCK(cc); 1202 return (1); 1203 } 1204 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1205 c, c->c_func, c->c_arg); 1206 CC_UNLOCK(cc); 1207 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 1208 return (0); 1209 } 1210 if (sq_locked) 1211 sleepq_release(&cc->cc_exec_entity[direct].cc_waiting); 1212 1213 c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING); 1214 1215 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1216 c, c->c_func, c->c_arg); 1217 if ((c->c_flags & CALLOUT_PROCESSED) == 0) { 1218 if (cc->cc_exec_next_dir == c) 1219 cc->cc_exec_next_dir = LIST_NEXT(c, c_links.le); 1220 LIST_REMOVE(c, c_links.le); 1221 } else 1222 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1223 callout_cc_del(c, cc); 1224 1225 CC_UNLOCK(cc); 1226 return (1); 1227 } 1228 1229 void 1230 callout_init(c, mpsafe) 1231 struct callout *c; 1232 int mpsafe; 1233 { 1234 bzero(c, sizeof *c); 1235 if (mpsafe) { 1236 c->c_lock = NULL; 1237 c->c_flags = CALLOUT_RETURNUNLOCKED; 1238 } else { 1239 c->c_lock = &Giant.lock_object; 1240 c->c_flags = 0; 1241 } 1242 c->c_cpu = timeout_cpu; 1243 } 1244 1245 void 1246 _callout_init_lock(c, lock, flags) 1247 struct callout *c; 1248 struct lock_object *lock; 1249 int flags; 1250 { 1251 bzero(c, sizeof *c); 1252 c->c_lock = lock; 1253 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1254 ("callout_init_lock: bad flags %d", flags)); 1255 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1256 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1257 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & 1258 (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class", 1259 __func__)); 1260 c->c_flags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1261 c->c_cpu = timeout_cpu; 1262 } 1263 1264 #ifdef APM_FIXUP_CALLTODO 1265 /* 1266 * Adjust the kernel calltodo timeout list. This routine is used after 1267 * an APM resume to recalculate the calltodo timer list values with the 1268 * number of hz's we have been sleeping. The next hardclock() will detect 1269 * that there are fired timers and run softclock() to execute them. 1270 * 1271 * Please note, I have not done an exhaustive analysis of what code this 1272 * might break. I am motivated to have my select()'s and alarm()'s that 1273 * have expired during suspend firing upon resume so that the applications 1274 * which set the timer can do the maintanence the timer was for as close 1275 * as possible to the originally intended time. Testing this code for a 1276 * week showed that resuming from a suspend resulted in 22 to 25 timers 1277 * firing, which seemed independant on whether the suspend was 2 hours or 1278 * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu> 1279 */ 1280 void 1281 adjust_timeout_calltodo(time_change) 1282 struct timeval *time_change; 1283 { 1284 register struct callout *p; 1285 unsigned long delta_ticks; 1286 1287 /* 1288 * How many ticks were we asleep? 1289 * (stolen from tvtohz()). 1290 */ 1291 1292 /* Don't do anything */ 1293 if (time_change->tv_sec < 0) 1294 return; 1295 else if (time_change->tv_sec <= LONG_MAX / 1000000) 1296 delta_ticks = (time_change->tv_sec * 1000000 + 1297 time_change->tv_usec + (tick - 1)) / tick + 1; 1298 else if (time_change->tv_sec <= LONG_MAX / hz) 1299 delta_ticks = time_change->tv_sec * hz + 1300 (time_change->tv_usec + (tick - 1)) / tick + 1; 1301 else 1302 delta_ticks = LONG_MAX; 1303 1304 if (delta_ticks > INT_MAX) 1305 delta_ticks = INT_MAX; 1306 1307 /* 1308 * Now rip through the timer calltodo list looking for timers 1309 * to expire. 1310 */ 1311 1312 /* don't collide with softclock() */ 1313 CC_LOCK(cc); 1314 for (p = calltodo.c_next; p != NULL; p = p->c_next) { 1315 p->c_time -= delta_ticks; 1316 1317 /* Break if the timer had more time on it than delta_ticks */ 1318 if (p->c_time > 0) 1319 break; 1320 1321 /* take back the ticks the timer didn't use (p->c_time <= 0) */ 1322 delta_ticks = -p->c_time; 1323 } 1324 CC_UNLOCK(cc); 1325 1326 return; 1327 } 1328 #endif /* APM_FIXUP_CALLTODO */ 1329 1330 static int 1331 flssbt(sbintime_t sbt) 1332 { 1333 1334 sbt += (uint64_t)sbt >> 1; 1335 if (sizeof(long) >= sizeof(sbintime_t)) 1336 return (flsl(sbt)); 1337 if (sbt >= SBT_1S) 1338 return (flsl(((uint64_t)sbt) >> 32) + 32); 1339 return (flsl(sbt)); 1340 } 1341 1342 /* 1343 * Dump immediate statistic snapshot of the scheduled callouts. 1344 */ 1345 static int 1346 sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1347 { 1348 struct callout *tmp; 1349 struct callout_cpu *cc; 1350 struct callout_list *sc; 1351 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; 1352 int ct[64], cpr[64], ccpbk[32]; 1353 int error, val, i, count, tcum, pcum, maxc, c, medc; 1354 #ifdef SMP 1355 int cpu; 1356 #endif 1357 1358 val = 0; 1359 error = sysctl_handle_int(oidp, &val, 0, req); 1360 if (error != 0 || req->newptr == NULL) 1361 return (error); 1362 count = maxc = 0; 1363 st = spr = maxt = maxpr = 0; 1364 bzero(ccpbk, sizeof(ccpbk)); 1365 bzero(ct, sizeof(ct)); 1366 bzero(cpr, sizeof(cpr)); 1367 now = sbinuptime(); 1368 #ifdef SMP 1369 CPU_FOREACH(cpu) { 1370 cc = CC_CPU(cpu); 1371 #else 1372 cc = CC_CPU(timeout_cpu); 1373 #endif 1374 CC_LOCK(cc); 1375 for (i = 0; i < callwheelsize; i++) { 1376 sc = &cc->cc_callwheel[i]; 1377 c = 0; 1378 LIST_FOREACH(tmp, sc, c_links.le) { 1379 c++; 1380 t = tmp->c_time - now; 1381 if (t < 0) 1382 t = 0; 1383 st += t / SBT_1US; 1384 spr += tmp->c_precision / SBT_1US; 1385 if (t > maxt) 1386 maxt = t; 1387 if (tmp->c_precision > maxpr) 1388 maxpr = tmp->c_precision; 1389 ct[flssbt(t)]++; 1390 cpr[flssbt(tmp->c_precision)]++; 1391 } 1392 if (c > maxc) 1393 maxc = c; 1394 ccpbk[fls(c + c / 2)]++; 1395 count += c; 1396 } 1397 CC_UNLOCK(cc); 1398 #ifdef SMP 1399 } 1400 #endif 1401 1402 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1403 tcum += ct[i]; 1404 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1405 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) 1406 pcum += cpr[i]; 1407 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1408 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1409 c += ccpbk[i]; 1410 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1411 1412 printf("Scheduled callouts statistic snapshot:\n"); 1413 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1414 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1415 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1416 medc, 1417 count / callwheelsize / mp_ncpus, 1418 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1419 maxc); 1420 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1421 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1422 (st / count) / 1000000, (st / count) % 1000000, 1423 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); 1424 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1425 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, 1426 (spr / count) / 1000000, (spr / count) % 1000000, 1427 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); 1428 printf(" Distribution: \tbuckets\t time\t tcum\t" 1429 " prec\t pcum\n"); 1430 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1431 if (ct[i] == 0 && cpr[i] == 0) 1432 continue; 1433 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1434 tcum += ct[i]; 1435 pcum += cpr[i]; 1436 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", 1437 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1438 i - 1 - (32 - CC_HASH_SHIFT), 1439 ct[i], tcum, cpr[i], pcum); 1440 } 1441 return (error); 1442 } 1443 SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1444 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1445 0, 0, sysctl_kern_callout_stat, "I", 1446 "Dump immediate statistic snapshot of the scheduled callouts");
Cache object: 975957b027aca5cec0eb6ae48ed94d06
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]