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 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/bus.h> 48 #include <sys/callout.h> 49 #include <sys/file.h> 50 #include <sys/interrupt.h> 51 #include <sys/kernel.h> 52 #include <sys/ktr.h> 53 #include <sys/lock.h> 54 #include <sys/malloc.h> 55 #include <sys/mutex.h> 56 #include <sys/proc.h> 57 #include <sys/sdt.h> 58 #include <sys/sleepqueue.h> 59 #include <sys/sysctl.h> 60 #include <sys/smp.h> 61 62 #ifdef SMP 63 #include <machine/cpu.h> 64 #endif 65 66 #ifndef NO_EVENTTIMERS 67 DPCPU_DECLARE(sbintime_t, hardclocktime); 68 #endif 69 70 SDT_PROVIDER_DEFINE(callout_execute); 71 SDT_PROBE_DEFINE1(callout_execute, kernel, , callout__start, 72 "struct callout *"); 73 SDT_PROBE_DEFINE1(callout_execute, kernel, , callout__end, 74 "struct callout *"); 75 76 #ifdef CALLOUT_PROFILING 77 static int avg_depth; 78 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, 79 "Average number of items examined per softclock call. Units = 1/1000"); 80 static int avg_gcalls; 81 SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, 82 "Average number of Giant callouts made per softclock call. Units = 1/1000"); 83 static int avg_lockcalls; 84 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0, 85 "Average number of lock callouts made per softclock call. Units = 1/1000"); 86 static int avg_mpcalls; 87 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, 88 "Average number of MP callouts made per softclock call. Units = 1/1000"); 89 static int avg_depth_dir; 90 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0, 91 "Average number of direct callouts examined per callout_process call. " 92 "Units = 1/1000"); 93 static int avg_lockcalls_dir; 94 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD, 95 &avg_lockcalls_dir, 0, "Average number of lock direct callouts made per " 96 "callout_process call. Units = 1/1000"); 97 static int avg_mpcalls_dir; 98 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir, 99 0, "Average number of MP direct callouts made per callout_process call. " 100 "Units = 1/1000"); 101 #endif 102 103 static int ncallout; 104 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN, &ncallout, 0, 105 "Number of entries in callwheel and size of timeout() preallocation"); 106 107 /* 108 * TODO: 109 * allocate more timeout table slots when table overflows. 110 */ 111 u_int callwheelsize, callwheelmask; 112 113 /* 114 * The callout cpu exec entities represent informations necessary for 115 * describing the state of callouts currently running on the CPU and the ones 116 * necessary for migrating callouts to the new callout cpu. In particular, 117 * the first entry of the array cc_exec_entity holds informations for callout 118 * running in SWI thread context, while the second one holds informations 119 * for callout running directly from hardware interrupt context. 120 * The cached informations are very important for deferring migration when 121 * the migrating callout is already running. 122 */ 123 struct cc_exec { 124 struct callout *cc_next; 125 struct callout *cc_curr; 126 #ifdef SMP 127 void (*ce_migration_func)(void *); 128 void *ce_migration_arg; 129 int ce_migration_cpu; 130 sbintime_t ce_migration_time; 131 sbintime_t ce_migration_prec; 132 #endif 133 bool cc_cancel; 134 bool cc_waiting; 135 }; 136 137 /* 138 * There is one struct callout_cpu per cpu, holding all relevant 139 * state for the callout processing thread on the individual CPU. 140 */ 141 struct callout_cpu { 142 struct mtx_padalign cc_lock; 143 struct cc_exec cc_exec_entity[2]; 144 struct callout *cc_callout; 145 struct callout_list *cc_callwheel; 146 struct callout_tailq cc_expireq; 147 struct callout_slist cc_callfree; 148 sbintime_t cc_firstevent; 149 sbintime_t cc_lastscan; 150 void *cc_cookie; 151 u_int cc_bucket; 152 }; 153 154 #define cc_exec_curr cc_exec_entity[0].cc_curr 155 #define cc_exec_next cc_exec_entity[0].cc_next 156 #define cc_exec_cancel cc_exec_entity[0].cc_cancel 157 #define cc_exec_waiting cc_exec_entity[0].cc_waiting 158 #define cc_exec_curr_dir cc_exec_entity[1].cc_curr 159 #define cc_exec_next_dir cc_exec_entity[1].cc_next 160 #define cc_exec_cancel_dir cc_exec_entity[1].cc_cancel 161 #define cc_exec_waiting_dir cc_exec_entity[1].cc_waiting 162 163 #ifdef SMP 164 #define cc_migration_func cc_exec_entity[0].ce_migration_func 165 #define cc_migration_arg cc_exec_entity[0].ce_migration_arg 166 #define cc_migration_cpu cc_exec_entity[0].ce_migration_cpu 167 #define cc_migration_time cc_exec_entity[0].ce_migration_time 168 #define cc_migration_prec cc_exec_entity[0].ce_migration_prec 169 #define cc_migration_func_dir cc_exec_entity[1].ce_migration_func 170 #define cc_migration_arg_dir cc_exec_entity[1].ce_migration_arg 171 #define cc_migration_cpu_dir cc_exec_entity[1].ce_migration_cpu 172 #define cc_migration_time_dir cc_exec_entity[1].ce_migration_time 173 #define cc_migration_prec_dir cc_exec_entity[1].ce_migration_prec 174 175 struct callout_cpu cc_cpu[MAXCPU]; 176 #define CPUBLOCK MAXCPU 177 #define CC_CPU(cpu) (&cc_cpu[(cpu)]) 178 #define CC_SELF() CC_CPU(PCPU_GET(cpuid)) 179 #else 180 struct callout_cpu cc_cpu; 181 #define CC_CPU(cpu) &cc_cpu 182 #define CC_SELF() &cc_cpu 183 #endif 184 #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) 185 #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) 186 #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) 187 188 static int timeout_cpu; 189 190 static void callout_cpu_init(struct callout_cpu *cc); 191 static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, 192 #ifdef CALLOUT_PROFILING 193 int *mpcalls, int *lockcalls, int *gcalls, 194 #endif 195 int direct); 196 197 static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); 198 199 /** 200 * Locked by cc_lock: 201 * cc_curr - If a callout is in progress, it is cc_curr. 202 * If cc_curr is non-NULL, threads waiting in 203 * callout_drain() will be woken up as soon as the 204 * relevant callout completes. 205 * cc_cancel - Changing to 1 with both callout_lock and cc_lock held 206 * guarantees that the current callout will not run. 207 * The softclock() function sets this to 0 before it 208 * drops callout_lock to acquire c_lock, and it calls 209 * the handler only if curr_cancelled is still 0 after 210 * cc_lock is successfully acquired. 211 * cc_waiting - If a thread is waiting in callout_drain(), then 212 * callout_wait is nonzero. Set only when 213 * cc_curr is non-NULL. 214 */ 215 216 /* 217 * Resets the execution entity tied to a specific callout cpu. 218 */ 219 static void 220 cc_cce_cleanup(struct callout_cpu *cc, int direct) 221 { 222 223 cc->cc_exec_entity[direct].cc_curr = NULL; 224 cc->cc_exec_entity[direct].cc_next = NULL; 225 cc->cc_exec_entity[direct].cc_cancel = false; 226 cc->cc_exec_entity[direct].cc_waiting = false; 227 #ifdef SMP 228 cc->cc_exec_entity[direct].ce_migration_cpu = CPUBLOCK; 229 cc->cc_exec_entity[direct].ce_migration_time = 0; 230 cc->cc_exec_entity[direct].ce_migration_prec = 0; 231 cc->cc_exec_entity[direct].ce_migration_func = NULL; 232 cc->cc_exec_entity[direct].ce_migration_arg = NULL; 233 #endif 234 } 235 236 /* 237 * Checks if migration is requested by a specific callout cpu. 238 */ 239 static int 240 cc_cce_migrating(struct callout_cpu *cc, int direct) 241 { 242 243 #ifdef SMP 244 return (cc->cc_exec_entity[direct].ce_migration_cpu != CPUBLOCK); 245 #else 246 return (0); 247 #endif 248 } 249 250 /* 251 * Kernel low level callwheel initialization 252 * called on cpu0 during kernel startup. 253 */ 254 static void 255 callout_callwheel_init(void *dummy) 256 { 257 struct callout_cpu *cc; 258 259 /* 260 * Calculate the size of the callout wheel and the preallocated 261 * timeout() structures. 262 * XXX: Clip callout to result of previous function of maxusers 263 * maximum 384. This is still huge, but acceptable. 264 */ 265 ncallout = imin(16 + maxproc + maxfiles, 18508); 266 TUNABLE_INT_FETCH("kern.ncallout", &ncallout); 267 268 /* 269 * Calculate callout wheel size, should be next power of two higher 270 * than 'ncallout'. 271 */ 272 callwheelsize = 1 << fls(ncallout); 273 callwheelmask = callwheelsize - 1; 274 275 /* 276 * Only cpu0 handles timeout(9) and receives a preallocation. 277 * 278 * XXX: Once all timeout(9) consumers are converted this can 279 * be removed. 280 */ 281 timeout_cpu = PCPU_GET(cpuid); 282 cc = CC_CPU(timeout_cpu); 283 cc->cc_callout = malloc(ncallout * sizeof(struct callout), 284 M_CALLOUT, M_WAITOK); 285 callout_cpu_init(cc); 286 } 287 SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); 288 289 /* 290 * Initialize the per-cpu callout structures. 291 */ 292 static void 293 callout_cpu_init(struct callout_cpu *cc) 294 { 295 struct callout *c; 296 int i; 297 298 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); 299 SLIST_INIT(&cc->cc_callfree); 300 cc->cc_callwheel = malloc(sizeof(struct callout_list) * callwheelsize, 301 M_CALLOUT, M_WAITOK); 302 for (i = 0; i < callwheelsize; i++) 303 LIST_INIT(&cc->cc_callwheel[i]); 304 TAILQ_INIT(&cc->cc_expireq); 305 cc->cc_firstevent = INT64_MAX; 306 for (i = 0; i < 2; i++) 307 cc_cce_cleanup(cc, i); 308 if (cc->cc_callout == NULL) /* Only cpu0 handles timeout(9) */ 309 return; 310 for (i = 0; i < ncallout; i++) { 311 c = &cc->cc_callout[i]; 312 callout_init(c, 0); 313 c->c_flags = CALLOUT_LOCAL_ALLOC; 314 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 315 } 316 } 317 318 #ifdef SMP 319 /* 320 * Switches the cpu tied to a specific callout. 321 * The function expects a locked incoming callout cpu and returns with 322 * locked outcoming callout cpu. 323 */ 324 static struct callout_cpu * 325 callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu) 326 { 327 struct callout_cpu *new_cc; 328 329 MPASS(c != NULL && cc != NULL); 330 CC_LOCK_ASSERT(cc); 331 332 /* 333 * Avoid interrupts and preemption firing after the callout cpu 334 * is blocked in order to avoid deadlocks as the new thread 335 * may be willing to acquire the callout cpu lock. 336 */ 337 c->c_cpu = CPUBLOCK; 338 spinlock_enter(); 339 CC_UNLOCK(cc); 340 new_cc = CC_CPU(new_cpu); 341 CC_LOCK(new_cc); 342 spinlock_exit(); 343 c->c_cpu = new_cpu; 344 return (new_cc); 345 } 346 #endif 347 348 /* 349 * Start standard softclock thread. 350 */ 351 static void 352 start_softclock(void *dummy) 353 { 354 struct callout_cpu *cc; 355 #ifdef SMP 356 int cpu; 357 #endif 358 359 cc = CC_CPU(timeout_cpu); 360 if (swi_add(&clk_intr_event, "clock", softclock, cc, SWI_CLOCK, 361 INTR_MPSAFE, &cc->cc_cookie)) 362 panic("died while creating standard software ithreads"); 363 #ifdef SMP 364 CPU_FOREACH(cpu) { 365 if (cpu == timeout_cpu) 366 continue; 367 cc = CC_CPU(cpu); 368 cc->cc_callout = NULL; /* Only cpu0 handles timeout(9). */ 369 callout_cpu_init(cc); 370 if (swi_add(NULL, "clock", softclock, cc, SWI_CLOCK, 371 INTR_MPSAFE, &cc->cc_cookie)) 372 panic("died while creating standard software ithreads"); 373 } 374 #endif 375 } 376 SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); 377 378 #define CC_HASH_SHIFT 8 379 380 static inline u_int 381 callout_hash(sbintime_t sbt) 382 { 383 384 return (sbt >> (32 - CC_HASH_SHIFT)); 385 } 386 387 static inline u_int 388 callout_get_bucket(sbintime_t sbt) 389 { 390 391 return (callout_hash(sbt) & callwheelmask); 392 } 393 394 void 395 callout_process(sbintime_t now) 396 { 397 struct callout *tmp, *tmpn; 398 struct callout_cpu *cc; 399 struct callout_list *sc; 400 sbintime_t first, last, max, tmp_max; 401 uint32_t lookahead; 402 u_int firstb, lastb, nowb; 403 #ifdef CALLOUT_PROFILING 404 int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0; 405 #endif 406 407 cc = CC_SELF(); 408 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET); 409 410 /* Compute the buckets of the last scan and present times. */ 411 firstb = callout_hash(cc->cc_lastscan); 412 cc->cc_lastscan = now; 413 nowb = callout_hash(now); 414 415 /* Compute the last bucket and minimum time of the bucket after it. */ 416 if (nowb == firstb) 417 lookahead = (SBT_1S / 16); 418 else if (nowb - firstb == 1) 419 lookahead = (SBT_1S / 8); 420 else 421 lookahead = (SBT_1S / 2); 422 first = last = now; 423 first += (lookahead / 2); 424 last += lookahead; 425 last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); 426 lastb = callout_hash(last) - 1; 427 max = last; 428 429 /* 430 * Check if we wrapped around the entire wheel from the last scan. 431 * In case, we need to scan entirely the wheel for pending callouts. 432 */ 433 if (lastb - firstb >= callwheelsize) { 434 lastb = firstb + callwheelsize - 1; 435 if (nowb - firstb >= callwheelsize) 436 nowb = lastb; 437 } 438 439 /* Iterate callwheel from firstb to nowb and then up to lastb. */ 440 do { 441 sc = &cc->cc_callwheel[firstb & callwheelmask]; 442 tmp = LIST_FIRST(sc); 443 while (tmp != NULL) { 444 /* Run the callout if present time within allowed. */ 445 if (tmp->c_time <= now) { 446 /* 447 * Consumer told us the callout may be run 448 * directly from hardware interrupt context. 449 */ 450 if (tmp->c_flags & CALLOUT_DIRECT) { 451 #ifdef CALLOUT_PROFILING 452 ++depth_dir; 453 #endif 454 cc->cc_exec_next_dir = 455 LIST_NEXT(tmp, c_links.le); 456 cc->cc_bucket = firstb & callwheelmask; 457 LIST_REMOVE(tmp, c_links.le); 458 softclock_call_cc(tmp, cc, 459 #ifdef CALLOUT_PROFILING 460 &mpcalls_dir, &lockcalls_dir, NULL, 461 #endif 462 1); 463 tmp = cc->cc_exec_next_dir; 464 } else { 465 tmpn = LIST_NEXT(tmp, c_links.le); 466 LIST_REMOVE(tmp, c_links.le); 467 TAILQ_INSERT_TAIL(&cc->cc_expireq, 468 tmp, c_links.tqe); 469 tmp->c_flags |= CALLOUT_PROCESSED; 470 tmp = tmpn; 471 } 472 continue; 473 } 474 /* Skip events from distant future. */ 475 if (tmp->c_time >= max) 476 goto next; 477 /* 478 * Event minimal time is bigger than present maximal 479 * time, so it cannot be aggregated. 480 */ 481 if (tmp->c_time > last) { 482 lastb = nowb; 483 goto next; 484 } 485 /* Update first and last time, respecting this event. */ 486 if (tmp->c_time < first) 487 first = tmp->c_time; 488 tmp_max = tmp->c_time + tmp->c_precision; 489 if (tmp_max < last) 490 last = tmp_max; 491 next: 492 tmp = LIST_NEXT(tmp, c_links.le); 493 } 494 /* Proceed with the next bucket. */ 495 firstb++; 496 /* 497 * Stop if we looked after present time and found 498 * some event we can't execute at now. 499 * Stop if we looked far enough into the future. 500 */ 501 } while (((int)(firstb - lastb)) <= 0); 502 cc->cc_firstevent = last; 503 #ifndef NO_EVENTTIMERS 504 cpu_new_callout(curcpu, last, first); 505 #endif 506 #ifdef CALLOUT_PROFILING 507 avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8; 508 avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8; 509 avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8; 510 #endif 511 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 512 /* 513 * swi_sched acquires the thread lock, so we don't want to call it 514 * with cc_lock held; incorrect locking order. 515 */ 516 if (!TAILQ_EMPTY(&cc->cc_expireq)) 517 swi_sched(cc->cc_cookie, 0); 518 } 519 520 static struct callout_cpu * 521 callout_lock(struct callout *c) 522 { 523 struct callout_cpu *cc; 524 int cpu; 525 526 for (;;) { 527 cpu = c->c_cpu; 528 #ifdef SMP 529 if (cpu == CPUBLOCK) { 530 while (c->c_cpu == CPUBLOCK) 531 cpu_spinwait(); 532 continue; 533 } 534 #endif 535 cc = CC_CPU(cpu); 536 CC_LOCK(cc); 537 if (cpu == c->c_cpu) 538 break; 539 CC_UNLOCK(cc); 540 } 541 return (cc); 542 } 543 544 static void 545 callout_cc_add(struct callout *c, struct callout_cpu *cc, 546 sbintime_t sbt, sbintime_t precision, void (*func)(void *), 547 void *arg, int cpu, int flags) 548 { 549 int bucket; 550 551 CC_LOCK_ASSERT(cc); 552 if (sbt < cc->cc_lastscan) 553 sbt = cc->cc_lastscan; 554 c->c_arg = arg; 555 c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING); 556 if (flags & C_DIRECT_EXEC) 557 c->c_flags |= CALLOUT_DIRECT; 558 c->c_flags &= ~CALLOUT_PROCESSED; 559 c->c_func = func; 560 c->c_time = sbt; 561 c->c_precision = precision; 562 bucket = callout_get_bucket(c->c_time); 563 CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x", 564 c, (int)(c->c_precision >> 32), 565 (u_int)(c->c_precision & 0xffffffff)); 566 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); 567 if (cc->cc_bucket == bucket) 568 cc->cc_exec_next_dir = c; 569 #ifndef NO_EVENTTIMERS 570 /* 571 * Inform the eventtimers(4) subsystem there's a new callout 572 * that has been inserted, but only if really required. 573 */ 574 if (INT64_MAX - c->c_time < c->c_precision) 575 c->c_precision = INT64_MAX - c->c_time; 576 sbt = c->c_time + c->c_precision; 577 if (sbt < cc->cc_firstevent) { 578 cc->cc_firstevent = sbt; 579 cpu_new_callout(cpu, sbt, c->c_time); 580 } 581 #endif 582 } 583 584 static void 585 callout_cc_del(struct callout *c, struct callout_cpu *cc) 586 { 587 588 if ((c->c_flags & CALLOUT_LOCAL_ALLOC) == 0) 589 return; 590 c->c_func = NULL; 591 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 592 } 593 594 static void 595 softclock_call_cc(struct callout *c, struct callout_cpu *cc, 596 #ifdef CALLOUT_PROFILING 597 int *mpcalls, int *lockcalls, int *gcalls, 598 #endif 599 int direct) 600 { 601 struct rm_priotracker tracker; 602 void (*c_func)(void *); 603 void *c_arg; 604 struct lock_class *class; 605 struct lock_object *c_lock; 606 uintptr_t lock_status; 607 int c_flags; 608 #ifdef SMP 609 struct callout_cpu *new_cc; 610 void (*new_func)(void *); 611 void *new_arg; 612 int flags, new_cpu; 613 sbintime_t new_prec, new_time; 614 #endif 615 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 616 sbintime_t sbt1, sbt2; 617 struct timespec ts2; 618 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 619 static timeout_t *lastfunc; 620 #endif 621 622 KASSERT((c->c_flags & (CALLOUT_PENDING | CALLOUT_ACTIVE)) == 623 (CALLOUT_PENDING | CALLOUT_ACTIVE), 624 ("softclock_call_cc: pend|act %p %x", c, c->c_flags)); 625 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; 626 lock_status = 0; 627 if (c->c_flags & CALLOUT_SHAREDLOCK) { 628 if (class == &lock_class_rm) 629 lock_status = (uintptr_t)&tracker; 630 else 631 lock_status = 1; 632 } 633 c_lock = c->c_lock; 634 c_func = c->c_func; 635 c_arg = c->c_arg; 636 c_flags = c->c_flags; 637 if (c->c_flags & CALLOUT_LOCAL_ALLOC) 638 c->c_flags = CALLOUT_LOCAL_ALLOC; 639 else 640 c->c_flags &= ~CALLOUT_PENDING; 641 cc->cc_exec_entity[direct].cc_curr = c; 642 cc->cc_exec_entity[direct].cc_cancel = false; 643 CC_UNLOCK(cc); 644 if (c_lock != NULL) { 645 class->lc_lock(c_lock, lock_status); 646 /* 647 * The callout may have been cancelled 648 * while we switched locks. 649 */ 650 if (cc->cc_exec_entity[direct].cc_cancel) { 651 class->lc_unlock(c_lock); 652 goto skip; 653 } 654 /* The callout cannot be stopped now. */ 655 cc->cc_exec_entity[direct].cc_cancel = true; 656 if (c_lock == &Giant.lock_object) { 657 #ifdef CALLOUT_PROFILING 658 (*gcalls)++; 659 #endif 660 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", 661 c, c_func, c_arg); 662 } else { 663 #ifdef CALLOUT_PROFILING 664 (*lockcalls)++; 665 #endif 666 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", 667 c, c_func, c_arg); 668 } 669 } else { 670 #ifdef CALLOUT_PROFILING 671 (*mpcalls)++; 672 #endif 673 CTR3(KTR_CALLOUT, "callout %p func %p arg %p", 674 c, c_func, c_arg); 675 } 676 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 677 sbt1 = sbinuptime(); 678 #endif 679 THREAD_NO_SLEEPING(); 680 SDT_PROBE(callout_execute, kernel, , callout__start, c, 0, 0, 0, 0); 681 c_func(c_arg); 682 SDT_PROBE(callout_execute, kernel, , callout__end, c, 0, 0, 0, 0); 683 THREAD_SLEEPING_OK(); 684 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 685 sbt2 = sbinuptime(); 686 sbt2 -= sbt1; 687 if (sbt2 > maxdt) { 688 if (lastfunc != c_func || sbt2 > maxdt * 2) { 689 ts2 = sbttots(sbt2); 690 printf( 691 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 692 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); 693 } 694 maxdt = sbt2; 695 lastfunc = c_func; 696 } 697 #endif 698 CTR1(KTR_CALLOUT, "callout %p finished", c); 699 if ((c_flags & CALLOUT_RETURNUNLOCKED) == 0) 700 class->lc_unlock(c_lock); 701 skip: 702 CC_LOCK(cc); 703 KASSERT(cc->cc_exec_entity[direct].cc_curr == c, ("mishandled cc_curr")); 704 cc->cc_exec_entity[direct].cc_curr = NULL; 705 if (cc->cc_exec_entity[direct].cc_waiting) { 706 /* 707 * There is someone waiting for the 708 * callout to complete. 709 * If the callout was scheduled for 710 * migration just cancel it. 711 */ 712 if (cc_cce_migrating(cc, direct)) { 713 cc_cce_cleanup(cc, direct); 714 715 /* 716 * It should be assert here that the callout is not 717 * destroyed but that is not easy. 718 */ 719 c->c_flags &= ~CALLOUT_DFRMIGRATION; 720 } 721 cc->cc_exec_entity[direct].cc_waiting = false; 722 CC_UNLOCK(cc); 723 wakeup(&cc->cc_exec_entity[direct].cc_waiting); 724 CC_LOCK(cc); 725 } else if (cc_cce_migrating(cc, direct)) { 726 KASSERT((c_flags & CALLOUT_LOCAL_ALLOC) == 0, 727 ("Migrating legacy callout %p", c)); 728 #ifdef SMP 729 /* 730 * If the callout was scheduled for 731 * migration just perform it now. 732 */ 733 new_cpu = cc->cc_exec_entity[direct].ce_migration_cpu; 734 new_time = cc->cc_exec_entity[direct].ce_migration_time; 735 new_prec = cc->cc_exec_entity[direct].ce_migration_prec; 736 new_func = cc->cc_exec_entity[direct].ce_migration_func; 737 new_arg = cc->cc_exec_entity[direct].ce_migration_arg; 738 cc_cce_cleanup(cc, direct); 739 740 /* 741 * It should be assert here that the callout is not destroyed 742 * but that is not easy. 743 * 744 * As first thing, handle deferred callout stops. 745 */ 746 if ((c->c_flags & CALLOUT_DFRMIGRATION) == 0) { 747 CTR3(KTR_CALLOUT, 748 "deferred cancelled %p func %p arg %p", 749 c, new_func, new_arg); 750 callout_cc_del(c, cc); 751 return; 752 } 753 c->c_flags &= ~CALLOUT_DFRMIGRATION; 754 755 new_cc = callout_cpu_switch(c, cc, new_cpu); 756 flags = (direct) ? C_DIRECT_EXEC : 0; 757 callout_cc_add(c, new_cc, new_time, new_prec, new_func, 758 new_arg, new_cpu, flags); 759 CC_UNLOCK(new_cc); 760 CC_LOCK(cc); 761 #else 762 panic("migration should not happen"); 763 #endif 764 } 765 /* 766 * If the current callout is locally allocated (from 767 * timeout(9)) then put it on the freelist. 768 * 769 * Note: we need to check the cached copy of c_flags because 770 * if it was not local, then it's not safe to deref the 771 * callout pointer. 772 */ 773 KASSERT((c_flags & CALLOUT_LOCAL_ALLOC) == 0 || 774 c->c_flags == CALLOUT_LOCAL_ALLOC, 775 ("corrupted callout")); 776 if (c_flags & CALLOUT_LOCAL_ALLOC) 777 callout_cc_del(c, cc); 778 } 779 780 /* 781 * The callout mechanism is based on the work of Adam M. Costello and 782 * George Varghese, published in a technical report entitled "Redesigning 783 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 784 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 785 * used in this implementation was published by G. Varghese and T. Lauck in 786 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 787 * the Efficient Implementation of a Timer Facility" in the Proceedings of 788 * the 11th ACM Annual Symposium on Operating Systems Principles, 789 * Austin, Texas Nov 1987. 790 */ 791 792 /* 793 * Software (low priority) clock interrupt. 794 * Run periodic events from timeout queue. 795 */ 796 void 797 softclock(void *arg) 798 { 799 struct callout_cpu *cc; 800 struct callout *c; 801 #ifdef CALLOUT_PROFILING 802 int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0; 803 #endif 804 805 cc = (struct callout_cpu *)arg; 806 CC_LOCK(cc); 807 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { 808 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 809 softclock_call_cc(c, cc, 810 #ifdef CALLOUT_PROFILING 811 &mpcalls, &lockcalls, &gcalls, 812 #endif 813 0); 814 #ifdef CALLOUT_PROFILING 815 ++depth; 816 #endif 817 } 818 #ifdef CALLOUT_PROFILING 819 avg_depth += (depth * 1000 - avg_depth) >> 8; 820 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 821 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 822 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 823 #endif 824 CC_UNLOCK(cc); 825 } 826 827 /* 828 * timeout -- 829 * Execute a function after a specified length of time. 830 * 831 * untimeout -- 832 * Cancel previous timeout function call. 833 * 834 * callout_handle_init -- 835 * Initialize a handle so that using it with untimeout is benign. 836 * 837 * See AT&T BCI Driver Reference Manual for specification. This 838 * implementation differs from that one in that although an 839 * identification value is returned from timeout, the original 840 * arguments to timeout as well as the identifier are used to 841 * identify entries for untimeout. 842 */ 843 struct callout_handle 844 timeout(ftn, arg, to_ticks) 845 timeout_t *ftn; 846 void *arg; 847 int to_ticks; 848 { 849 struct callout_cpu *cc; 850 struct callout *new; 851 struct callout_handle handle; 852 853 cc = CC_CPU(timeout_cpu); 854 CC_LOCK(cc); 855 /* Fill in the next free callout structure. */ 856 new = SLIST_FIRST(&cc->cc_callfree); 857 if (new == NULL) 858 /* XXX Attempt to malloc first */ 859 panic("timeout table full"); 860 SLIST_REMOVE_HEAD(&cc->cc_callfree, c_links.sle); 861 callout_reset(new, to_ticks, ftn, arg); 862 handle.callout = new; 863 CC_UNLOCK(cc); 864 865 return (handle); 866 } 867 868 void 869 untimeout(ftn, arg, handle) 870 timeout_t *ftn; 871 void *arg; 872 struct callout_handle handle; 873 { 874 struct callout_cpu *cc; 875 876 /* 877 * Check for a handle that was initialized 878 * by callout_handle_init, but never used 879 * for a real timeout. 880 */ 881 if (handle.callout == NULL) 882 return; 883 884 cc = callout_lock(handle.callout); 885 if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) 886 callout_stop(handle.callout); 887 CC_UNLOCK(cc); 888 } 889 890 void 891 callout_handle_init(struct callout_handle *handle) 892 { 893 handle->callout = NULL; 894 } 895 896 /* 897 * New interface; clients allocate their own callout structures. 898 * 899 * callout_reset() - establish or change a timeout 900 * callout_stop() - disestablish a timeout 901 * callout_init() - initialize a callout structure so that it can 902 * safely be passed to callout_reset() and callout_stop() 903 * 904 * <sys/callout.h> defines three convenience macros: 905 * 906 * callout_active() - returns truth if callout has not been stopped, 907 * drained, or deactivated since the last time the callout was 908 * reset. 909 * callout_pending() - returns truth if callout is still waiting for timeout 910 * callout_deactivate() - marks the callout as having been serviced 911 */ 912 int 913 callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t precision, 914 void (*ftn)(void *), void *arg, int cpu, int flags) 915 { 916 sbintime_t to_sbt, pr; 917 struct callout_cpu *cc; 918 int cancelled, direct; 919 920 cancelled = 0; 921 if (flags & C_ABSOLUTE) { 922 to_sbt = sbt; 923 } else { 924 if ((flags & C_HARDCLOCK) && (sbt < tick_sbt)) 925 sbt = tick_sbt; 926 if ((flags & C_HARDCLOCK) || 927 #ifdef NO_EVENTTIMERS 928 sbt >= sbt_timethreshold) { 929 to_sbt = getsbinuptime(); 930 931 /* Add safety belt for the case of hz > 1000. */ 932 to_sbt += tc_tick_sbt - tick_sbt; 933 #else 934 sbt >= sbt_tickthreshold) { 935 /* 936 * Obtain the time of the last hardclock() call on 937 * this CPU directly from the kern_clocksource.c. 938 * This value is per-CPU, but it is equal for all 939 * active ones. 940 */ 941 #ifdef __LP64__ 942 to_sbt = DPCPU_GET(hardclocktime); 943 #else 944 spinlock_enter(); 945 to_sbt = DPCPU_GET(hardclocktime); 946 spinlock_exit(); 947 #endif 948 #endif 949 if ((flags & C_HARDCLOCK) == 0) 950 to_sbt += tick_sbt; 951 } else 952 to_sbt = sbinuptime(); 953 if (INT64_MAX - to_sbt < sbt) 954 to_sbt = INT64_MAX; 955 else 956 to_sbt += sbt; 957 pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : 958 sbt >> C_PRELGET(flags)); 959 if (pr > precision) 960 precision = pr; 961 } 962 /* 963 * Don't allow migration of pre-allocated callouts lest they 964 * become unbalanced. 965 */ 966 if (c->c_flags & CALLOUT_LOCAL_ALLOC) 967 cpu = c->c_cpu; 968 direct = (c->c_flags & CALLOUT_DIRECT) != 0; 969 KASSERT(!direct || c->c_lock == NULL, 970 ("%s: direct callout %p has lock", __func__, c)); 971 cc = callout_lock(c); 972 if (cc->cc_exec_entity[direct].cc_curr == c) { 973 /* 974 * We're being asked to reschedule a callout which is 975 * currently in progress. If there is a lock then we 976 * can cancel the callout if it has not really started. 977 */ 978 if (c->c_lock != NULL && !cc->cc_exec_entity[direct].cc_cancel) 979 cancelled = cc->cc_exec_entity[direct].cc_cancel = true; 980 if (cc->cc_exec_entity[direct].cc_waiting) { 981 /* 982 * Someone has called callout_drain to kill this 983 * callout. Don't reschedule. 984 */ 985 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 986 cancelled ? "cancelled" : "failed to cancel", 987 c, c->c_func, c->c_arg); 988 CC_UNLOCK(cc); 989 return (cancelled); 990 } 991 } 992 if (c->c_flags & CALLOUT_PENDING) { 993 if ((c->c_flags & CALLOUT_PROCESSED) == 0) { 994 if (cc->cc_exec_next_dir == c) 995 cc->cc_exec_next_dir = LIST_NEXT(c, c_links.le); 996 LIST_REMOVE(c, c_links.le); 997 } else 998 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 999 cancelled = 1; 1000 c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING); 1001 } 1002 1003 #ifdef SMP 1004 /* 1005 * If the callout must migrate try to perform it immediately. 1006 * If the callout is currently running, just defer the migration 1007 * to a more appropriate moment. 1008 */ 1009 if (c->c_cpu != cpu) { 1010 if (cc->cc_exec_entity[direct].cc_curr == c) { 1011 cc->cc_exec_entity[direct].ce_migration_cpu = cpu; 1012 cc->cc_exec_entity[direct].ce_migration_time 1013 = to_sbt; 1014 cc->cc_exec_entity[direct].ce_migration_prec 1015 = precision; 1016 cc->cc_exec_entity[direct].ce_migration_func = ftn; 1017 cc->cc_exec_entity[direct].ce_migration_arg = arg; 1018 c->c_flags |= CALLOUT_DFRMIGRATION; 1019 CTR6(KTR_CALLOUT, 1020 "migration of %p func %p arg %p in %d.%08x to %u deferred", 1021 c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1022 (u_int)(to_sbt & 0xffffffff), cpu); 1023 CC_UNLOCK(cc); 1024 return (cancelled); 1025 } 1026 cc = callout_cpu_switch(c, cc, cpu); 1027 } 1028 #endif 1029 1030 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags); 1031 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", 1032 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1033 (u_int)(to_sbt & 0xffffffff)); 1034 CC_UNLOCK(cc); 1035 1036 return (cancelled); 1037 } 1038 1039 /* 1040 * Common idioms that can be optimized in the future. 1041 */ 1042 int 1043 callout_schedule_on(struct callout *c, int to_ticks, int cpu) 1044 { 1045 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 1046 } 1047 1048 int 1049 callout_schedule(struct callout *c, int to_ticks) 1050 { 1051 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 1052 } 1053 1054 int 1055 _callout_stop_safe(c, safe) 1056 struct callout *c; 1057 int safe; 1058 { 1059 struct callout_cpu *cc, *old_cc; 1060 struct lock_class *class; 1061 int direct, sq_locked, use_lock; 1062 1063 /* 1064 * Some old subsystems don't hold Giant while running a callout_stop(), 1065 * so just discard this check for the moment. 1066 */ 1067 if (!safe && c->c_lock != NULL) { 1068 if (c->c_lock == &Giant.lock_object) 1069 use_lock = mtx_owned(&Giant); 1070 else { 1071 use_lock = 1; 1072 class = LOCK_CLASS(c->c_lock); 1073 class->lc_assert(c->c_lock, LA_XLOCKED); 1074 } 1075 } else 1076 use_lock = 0; 1077 direct = (c->c_flags & CALLOUT_DIRECT) != 0; 1078 sq_locked = 0; 1079 old_cc = NULL; 1080 again: 1081 cc = callout_lock(c); 1082 1083 /* 1084 * If the callout was migrating while the callout cpu lock was 1085 * dropped, just drop the sleepqueue lock and check the states 1086 * again. 1087 */ 1088 if (sq_locked != 0 && cc != old_cc) { 1089 #ifdef SMP 1090 CC_UNLOCK(cc); 1091 sleepq_release(&old_cc->cc_exec_entity[direct].cc_waiting); 1092 sq_locked = 0; 1093 old_cc = NULL; 1094 goto again; 1095 #else 1096 panic("migration should not happen"); 1097 #endif 1098 } 1099 1100 /* 1101 * If the callout isn't pending, it's not on the queue, so 1102 * don't attempt to remove it from the queue. We can try to 1103 * stop it by other means however. 1104 */ 1105 if (!(c->c_flags & CALLOUT_PENDING)) { 1106 c->c_flags &= ~CALLOUT_ACTIVE; 1107 1108 /* 1109 * If it wasn't on the queue and it isn't the current 1110 * callout, then we can't stop it, so just bail. 1111 */ 1112 if (cc->cc_exec_entity[direct].cc_curr != c) { 1113 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1114 c, c->c_func, c->c_arg); 1115 CC_UNLOCK(cc); 1116 if (sq_locked) 1117 sleepq_release( 1118 &cc->cc_exec_entity[direct].cc_waiting); 1119 return (0); 1120 } 1121 1122 if (safe) { 1123 /* 1124 * The current callout is running (or just 1125 * about to run) and blocking is allowed, so 1126 * just wait for the current invocation to 1127 * finish. 1128 */ 1129 while (cc->cc_exec_entity[direct].cc_curr == c) { 1130 /* 1131 * Use direct calls to sleepqueue interface 1132 * instead of cv/msleep in order to avoid 1133 * a LOR between cc_lock and sleepqueue 1134 * chain spinlocks. This piece of code 1135 * emulates a msleep_spin() call actually. 1136 * 1137 * If we already have the sleepqueue chain 1138 * locked, then we can safely block. If we 1139 * don't already have it locked, however, 1140 * we have to drop the cc_lock to lock 1141 * it. This opens several races, so we 1142 * restart at the beginning once we have 1143 * both locks. If nothing has changed, then 1144 * we will end up back here with sq_locked 1145 * set. 1146 */ 1147 if (!sq_locked) { 1148 CC_UNLOCK(cc); 1149 sleepq_lock( 1150 &cc->cc_exec_entity[direct].cc_waiting); 1151 sq_locked = 1; 1152 old_cc = cc; 1153 goto again; 1154 } 1155 1156 /* 1157 * Migration could be cancelled here, but 1158 * as long as it is still not sure when it 1159 * will be packed up, just let softclock() 1160 * take care of it. 1161 */ 1162 cc->cc_exec_entity[direct].cc_waiting = true; 1163 DROP_GIANT(); 1164 CC_UNLOCK(cc); 1165 sleepq_add( 1166 &cc->cc_exec_entity[direct].cc_waiting, 1167 &cc->cc_lock.lock_object, "codrain", 1168 SLEEPQ_SLEEP, 0); 1169 sleepq_wait( 1170 &cc->cc_exec_entity[direct].cc_waiting, 1171 0); 1172 sq_locked = 0; 1173 old_cc = NULL; 1174 1175 /* Reacquire locks previously released. */ 1176 PICKUP_GIANT(); 1177 CC_LOCK(cc); 1178 } 1179 } else if (use_lock && 1180 !cc->cc_exec_entity[direct].cc_cancel) { 1181 /* 1182 * The current callout is waiting for its 1183 * lock which we hold. Cancel the callout 1184 * and return. After our caller drops the 1185 * lock, the callout will be skipped in 1186 * softclock(). 1187 */ 1188 cc->cc_exec_entity[direct].cc_cancel = true; 1189 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1190 c, c->c_func, c->c_arg); 1191 KASSERT(!cc_cce_migrating(cc, direct), 1192 ("callout wrongly scheduled for migration")); 1193 CC_UNLOCK(cc); 1194 KASSERT(!sq_locked, ("sleepqueue chain locked")); 1195 return (1); 1196 } else if ((c->c_flags & CALLOUT_DFRMIGRATION) != 0) { 1197 c->c_flags &= ~CALLOUT_DFRMIGRATION; 1198 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 1199 c, c->c_func, c->c_arg); 1200 CC_UNLOCK(cc); 1201 return (1); 1202 } 1203 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1204 c, c->c_func, c->c_arg); 1205 CC_UNLOCK(cc); 1206 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 1207 return (0); 1208 } 1209 if (sq_locked) 1210 sleepq_release(&cc->cc_exec_entity[direct].cc_waiting); 1211 1212 c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING); 1213 1214 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1215 c, c->c_func, c->c_arg); 1216 if ((c->c_flags & CALLOUT_PROCESSED) == 0) { 1217 if (cc->cc_exec_next_dir == c) 1218 cc->cc_exec_next_dir = LIST_NEXT(c, c_links.le); 1219 LIST_REMOVE(c, c_links.le); 1220 } else 1221 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1222 callout_cc_del(c, cc); 1223 1224 CC_UNLOCK(cc); 1225 return (1); 1226 } 1227 1228 void 1229 callout_init(c, mpsafe) 1230 struct callout *c; 1231 int mpsafe; 1232 { 1233 bzero(c, sizeof *c); 1234 if (mpsafe) { 1235 c->c_lock = NULL; 1236 c->c_flags = CALLOUT_RETURNUNLOCKED; 1237 } else { 1238 c->c_lock = &Giant.lock_object; 1239 c->c_flags = 0; 1240 } 1241 c->c_cpu = timeout_cpu; 1242 } 1243 1244 void 1245 _callout_init_lock(c, lock, flags) 1246 struct callout *c; 1247 struct lock_object *lock; 1248 int flags; 1249 { 1250 bzero(c, sizeof *c); 1251 c->c_lock = lock; 1252 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1253 ("callout_init_lock: bad flags %d", flags)); 1254 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1255 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1256 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & 1257 (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class", 1258 __func__)); 1259 c->c_flags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1260 c->c_cpu = timeout_cpu; 1261 } 1262 1263 #ifdef APM_FIXUP_CALLTODO 1264 /* 1265 * Adjust the kernel calltodo timeout list. This routine is used after 1266 * an APM resume to recalculate the calltodo timer list values with the 1267 * number of hz's we have been sleeping. The next hardclock() will detect 1268 * that there are fired timers and run softclock() to execute them. 1269 * 1270 * Please note, I have not done an exhaustive analysis of what code this 1271 * might break. I am motivated to have my select()'s and alarm()'s that 1272 * have expired during suspend firing upon resume so that the applications 1273 * which set the timer can do the maintanence the timer was for as close 1274 * as possible to the originally intended time. Testing this code for a 1275 * week showed that resuming from a suspend resulted in 22 to 25 timers 1276 * firing, which seemed independant on whether the suspend was 2 hours or 1277 * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu> 1278 */ 1279 void 1280 adjust_timeout_calltodo(time_change) 1281 struct timeval *time_change; 1282 { 1283 register struct callout *p; 1284 unsigned long delta_ticks; 1285 1286 /* 1287 * How many ticks were we asleep? 1288 * (stolen from tvtohz()). 1289 */ 1290 1291 /* Don't do anything */ 1292 if (time_change->tv_sec < 0) 1293 return; 1294 else if (time_change->tv_sec <= LONG_MAX / 1000000) 1295 delta_ticks = (time_change->tv_sec * 1000000 + 1296 time_change->tv_usec + (tick - 1)) / tick + 1; 1297 else if (time_change->tv_sec <= LONG_MAX / hz) 1298 delta_ticks = time_change->tv_sec * hz + 1299 (time_change->tv_usec + (tick - 1)) / tick + 1; 1300 else 1301 delta_ticks = LONG_MAX; 1302 1303 if (delta_ticks > INT_MAX) 1304 delta_ticks = INT_MAX; 1305 1306 /* 1307 * Now rip through the timer calltodo list looking for timers 1308 * to expire. 1309 */ 1310 1311 /* don't collide with softclock() */ 1312 CC_LOCK(cc); 1313 for (p = calltodo.c_next; p != NULL; p = p->c_next) { 1314 p->c_time -= delta_ticks; 1315 1316 /* Break if the timer had more time on it than delta_ticks */ 1317 if (p->c_time > 0) 1318 break; 1319 1320 /* take back the ticks the timer didn't use (p->c_time <= 0) */ 1321 delta_ticks = -p->c_time; 1322 } 1323 CC_UNLOCK(cc); 1324 1325 return; 1326 } 1327 #endif /* APM_FIXUP_CALLTODO */ 1328 1329 static int 1330 flssbt(sbintime_t sbt) 1331 { 1332 1333 sbt += (uint64_t)sbt >> 1; 1334 if (sizeof(long) >= sizeof(sbintime_t)) 1335 return (flsl(sbt)); 1336 if (sbt >= SBT_1S) 1337 return (flsl(((uint64_t)sbt) >> 32) + 32); 1338 return (flsl(sbt)); 1339 } 1340 1341 /* 1342 * Dump immediate statistic snapshot of the scheduled callouts. 1343 */ 1344 static int 1345 sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1346 { 1347 struct callout *tmp; 1348 struct callout_cpu *cc; 1349 struct callout_list *sc; 1350 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; 1351 int ct[64], cpr[64], ccpbk[32]; 1352 int error, val, i, count, tcum, pcum, maxc, c, medc; 1353 #ifdef SMP 1354 int cpu; 1355 #endif 1356 1357 val = 0; 1358 error = sysctl_handle_int(oidp, &val, 0, req); 1359 if (error != 0 || req->newptr == NULL) 1360 return (error); 1361 count = maxc = 0; 1362 st = spr = maxt = maxpr = 0; 1363 bzero(ccpbk, sizeof(ccpbk)); 1364 bzero(ct, sizeof(ct)); 1365 bzero(cpr, sizeof(cpr)); 1366 now = sbinuptime(); 1367 #ifdef SMP 1368 CPU_FOREACH(cpu) { 1369 cc = CC_CPU(cpu); 1370 #else 1371 cc = CC_CPU(timeout_cpu); 1372 #endif 1373 CC_LOCK(cc); 1374 for (i = 0; i < callwheelsize; i++) { 1375 sc = &cc->cc_callwheel[i]; 1376 c = 0; 1377 LIST_FOREACH(tmp, sc, c_links.le) { 1378 c++; 1379 t = tmp->c_time - now; 1380 if (t < 0) 1381 t = 0; 1382 st += t / SBT_1US; 1383 spr += tmp->c_precision / SBT_1US; 1384 if (t > maxt) 1385 maxt = t; 1386 if (tmp->c_precision > maxpr) 1387 maxpr = tmp->c_precision; 1388 ct[flssbt(t)]++; 1389 cpr[flssbt(tmp->c_precision)]++; 1390 } 1391 if (c > maxc) 1392 maxc = c; 1393 ccpbk[fls(c + c / 2)]++; 1394 count += c; 1395 } 1396 CC_UNLOCK(cc); 1397 #ifdef SMP 1398 } 1399 #endif 1400 1401 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1402 tcum += ct[i]; 1403 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1404 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) 1405 pcum += cpr[i]; 1406 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1407 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1408 c += ccpbk[i]; 1409 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1410 1411 printf("Scheduled callouts statistic snapshot:\n"); 1412 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1413 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1414 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1415 medc, 1416 count / callwheelsize / mp_ncpus, 1417 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1418 maxc); 1419 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1420 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1421 (st / count) / 1000000, (st / count) % 1000000, 1422 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); 1423 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1424 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, 1425 (spr / count) / 1000000, (spr / count) % 1000000, 1426 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); 1427 printf(" Distribution: \tbuckets\t time\t tcum\t" 1428 " prec\t pcum\n"); 1429 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1430 if (ct[i] == 0 && cpr[i] == 0) 1431 continue; 1432 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1433 tcum += ct[i]; 1434 pcum += cpr[i]; 1435 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", 1436 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1437 i - 1 - (32 - CC_HASH_SHIFT), 1438 ct[i], tcum, cpr[i], pcum); 1439 } 1440 return (error); 1441 } 1442 SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1443 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1444 0, 0, sysctl_kern_callout_stat, "I", 1445 "Dump immediate statistic snapshot of the scheduled callouts"); 1446