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_curr; 139 #ifdef SMP 140 void (*ce_migration_func)(void *); 141 void *ce_migration_arg; 142 int ce_migration_cpu; 143 sbintime_t ce_migration_time; 144 sbintime_t ce_migration_prec; 145 #endif 146 bool cc_cancel; 147 bool cc_waiting; 148 }; 149 150 /* 151 * There is one struct callout_cpu per cpu, holding all relevant 152 * state for the callout processing thread on the individual CPU. 153 */ 154 struct callout_cpu { 155 struct mtx_padalign cc_lock; 156 struct cc_exec cc_exec_entity[2]; 157 struct callout *cc_next; 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 u_int cc_inited; 167 char cc_ktr_event_name[20]; 168 }; 169 170 #define callout_migrating(c) ((c)->c_iflags & CALLOUT_DFRMIGRATION) 171 172 #define cc_exec_curr(cc, dir) cc->cc_exec_entity[dir].cc_curr 173 #define cc_exec_next(cc) cc->cc_next 174 #define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel 175 #define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting 176 #ifdef SMP 177 #define cc_migration_func(cc, dir) cc->cc_exec_entity[dir].ce_migration_func 178 #define cc_migration_arg(cc, dir) cc->cc_exec_entity[dir].ce_migration_arg 179 #define cc_migration_cpu(cc, dir) cc->cc_exec_entity[dir].ce_migration_cpu 180 #define cc_migration_time(cc, dir) cc->cc_exec_entity[dir].ce_migration_time 181 #define cc_migration_prec(cc, dir) cc->cc_exec_entity[dir].ce_migration_prec 182 183 struct callout_cpu cc_cpu[MAXCPU]; 184 #define CPUBLOCK MAXCPU 185 #define CC_CPU(cpu) (&cc_cpu[(cpu)]) 186 #define CC_SELF() CC_CPU(PCPU_GET(cpuid)) 187 #else 188 struct callout_cpu cc_cpu; 189 #define CC_CPU(cpu) &cc_cpu 190 #define CC_SELF() &cc_cpu 191 #endif 192 #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) 193 #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) 194 #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) 195 196 static int timeout_cpu; 197 198 static void callout_cpu_init(struct callout_cpu *cc, int cpu); 199 static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, 200 #ifdef CALLOUT_PROFILING 201 int *mpcalls, int *lockcalls, int *gcalls, 202 #endif 203 int direct); 204 205 static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); 206 207 /** 208 * Locked by cc_lock: 209 * cc_curr - If a callout is in progress, it is cc_curr. 210 * If cc_curr is non-NULL, threads waiting in 211 * callout_drain() will be woken up as soon as the 212 * relevant callout completes. 213 * cc_cancel - Changing to 1 with both callout_lock and cc_lock held 214 * guarantees that the current callout will not run. 215 * The softclock() function sets this to 0 before it 216 * drops callout_lock to acquire c_lock, and it calls 217 * the handler only if curr_cancelled is still 0 after 218 * cc_lock is successfully acquired. 219 * cc_waiting - If a thread is waiting in callout_drain(), then 220 * callout_wait is nonzero. Set only when 221 * cc_curr is non-NULL. 222 */ 223 224 /* 225 * Resets the execution entity tied to a specific callout cpu. 226 */ 227 static void 228 cc_cce_cleanup(struct callout_cpu *cc, int direct) 229 { 230 231 cc_exec_curr(cc, direct) = NULL; 232 cc_exec_cancel(cc, direct) = false; 233 cc_exec_waiting(cc, direct) = false; 234 #ifdef SMP 235 cc_migration_cpu(cc, direct) = CPUBLOCK; 236 cc_migration_time(cc, direct) = 0; 237 cc_migration_prec(cc, direct) = 0; 238 cc_migration_func(cc, direct) = NULL; 239 cc_migration_arg(cc, direct) = NULL; 240 #endif 241 } 242 243 /* 244 * Checks if migration is requested by a specific callout cpu. 245 */ 246 static int 247 cc_cce_migrating(struct callout_cpu *cc, int direct) 248 { 249 250 #ifdef SMP 251 return (cc_migration_cpu(cc, direct) != CPUBLOCK); 252 #else 253 return (0); 254 #endif 255 } 256 257 /* 258 * Kernel low level callwheel initialization 259 * called on cpu0 during kernel startup. 260 */ 261 static void 262 callout_callwheel_init(void *dummy) 263 { 264 struct callout_cpu *cc; 265 266 /* 267 * Calculate the size of the callout wheel and the preallocated 268 * timeout() structures. 269 * XXX: Clip callout to result of previous function of maxusers 270 * maximum 384. This is still huge, but acceptable. 271 */ 272 memset(CC_CPU(0), 0, sizeof(cc_cpu)); 273 ncallout = imin(16 + maxproc + maxfiles, 18508); 274 TUNABLE_INT_FETCH("kern.ncallout", &ncallout); 275 276 /* 277 * Calculate callout wheel size, should be next power of two higher 278 * than 'ncallout'. 279 */ 280 callwheelsize = 1 << fls(ncallout); 281 callwheelmask = callwheelsize - 1; 282 283 /* 284 * Fetch whether we're pinning the swi's or not. 285 */ 286 TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi); 287 TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi); 288 289 /* 290 * Only cpu0 handles timeout(9) and receives a preallocation. 291 * 292 * XXX: Once all timeout(9) consumers are converted this can 293 * be removed. 294 */ 295 timeout_cpu = PCPU_GET(cpuid); 296 cc = CC_CPU(timeout_cpu); 297 cc->cc_callout = malloc(ncallout * sizeof(struct callout), 298 M_CALLOUT, M_WAITOK); 299 callout_cpu_init(cc, timeout_cpu); 300 } 301 SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); 302 303 /* 304 * Initialize the per-cpu callout structures. 305 */ 306 static void 307 callout_cpu_init(struct callout_cpu *cc, int cpu) 308 { 309 struct callout *c; 310 int i; 311 312 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); 313 SLIST_INIT(&cc->cc_callfree); 314 cc->cc_inited = 1; 315 cc->cc_callwheel = malloc(sizeof(struct callout_list) * callwheelsize, 316 M_CALLOUT, M_WAITOK); 317 for (i = 0; i < callwheelsize; i++) 318 LIST_INIT(&cc->cc_callwheel[i]); 319 TAILQ_INIT(&cc->cc_expireq); 320 cc->cc_firstevent = SBT_MAX; 321 for (i = 0; i < 2; i++) 322 cc_cce_cleanup(cc, i); 323 snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name), 324 "callwheel cpu %d", cpu); 325 if (cc->cc_callout == NULL) /* Only cpu0 handles timeout(9) */ 326 return; 327 for (i = 0; i < ncallout; i++) { 328 c = &cc->cc_callout[i]; 329 callout_init(c, 0); 330 c->c_iflags = CALLOUT_LOCAL_ALLOC; 331 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 332 } 333 } 334 335 #ifdef SMP 336 /* 337 * Switches the cpu tied to a specific callout. 338 * The function expects a locked incoming callout cpu and returns with 339 * locked outcoming callout cpu. 340 */ 341 static struct callout_cpu * 342 callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu) 343 { 344 struct callout_cpu *new_cc; 345 346 MPASS(c != NULL && cc != NULL); 347 CC_LOCK_ASSERT(cc); 348 349 /* 350 * Avoid interrupts and preemption firing after the callout cpu 351 * is blocked in order to avoid deadlocks as the new thread 352 * may be willing to acquire the callout cpu lock. 353 */ 354 c->c_cpu = CPUBLOCK; 355 spinlock_enter(); 356 CC_UNLOCK(cc); 357 new_cc = CC_CPU(new_cpu); 358 CC_LOCK(new_cc); 359 spinlock_exit(); 360 c->c_cpu = new_cpu; 361 return (new_cc); 362 } 363 #endif 364 365 /* 366 * Start standard softclock thread. 367 */ 368 static void 369 start_softclock(void *dummy) 370 { 371 struct callout_cpu *cc; 372 char name[MAXCOMLEN]; 373 #ifdef SMP 374 int cpu; 375 struct intr_event *ie; 376 #endif 377 378 cc = CC_CPU(timeout_cpu); 379 snprintf(name, sizeof(name), "clock (%d)", timeout_cpu); 380 if (swi_add(&clk_intr_event, name, softclock, cc, SWI_CLOCK, 381 INTR_MPSAFE, &cc->cc_cookie)) 382 panic("died while creating standard software ithreads"); 383 if (pin_default_swi && 384 (intr_event_bind(clk_intr_event, timeout_cpu) != 0)) { 385 printf("%s: timeout clock couldn't be pinned to cpu %d\n", 386 __func__, 387 timeout_cpu); 388 } 389 390 #ifdef SMP 391 CPU_FOREACH(cpu) { 392 if (cpu == timeout_cpu) 393 continue; 394 cc = CC_CPU(cpu); 395 cc->cc_callout = NULL; /* Only cpu0 handles timeout(9). */ 396 callout_cpu_init(cc, cpu); 397 snprintf(name, sizeof(name), "clock (%d)", cpu); 398 ie = NULL; 399 if (swi_add(&ie, name, softclock, cc, SWI_CLOCK, 400 INTR_MPSAFE, &cc->cc_cookie)) 401 panic("died while creating standard software ithreads"); 402 if (pin_pcpu_swi && (intr_event_bind(ie, cpu) != 0)) { 403 printf("%s: per-cpu clock couldn't be pinned to " 404 "cpu %d\n", 405 __func__, 406 cpu); 407 } 408 } 409 #endif 410 } 411 SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); 412 413 #define CC_HASH_SHIFT 8 414 415 static inline u_int 416 callout_hash(sbintime_t sbt) 417 { 418 419 return (sbt >> (32 - CC_HASH_SHIFT)); 420 } 421 422 static inline u_int 423 callout_get_bucket(sbintime_t sbt) 424 { 425 426 return (callout_hash(sbt) & callwheelmask); 427 } 428 429 void 430 callout_process(sbintime_t now) 431 { 432 struct callout *tmp, *tmpn; 433 struct callout_cpu *cc; 434 struct callout_list *sc; 435 sbintime_t first, last, max, tmp_max; 436 uint32_t lookahead; 437 u_int firstb, lastb, nowb; 438 #ifdef CALLOUT_PROFILING 439 int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0; 440 #endif 441 442 cc = CC_SELF(); 443 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET); 444 445 /* Compute the buckets of the last scan and present times. */ 446 firstb = callout_hash(cc->cc_lastscan); 447 cc->cc_lastscan = now; 448 nowb = callout_hash(now); 449 450 /* Compute the last bucket and minimum time of the bucket after it. */ 451 if (nowb == firstb) 452 lookahead = (SBT_1S / 16); 453 else if (nowb - firstb == 1) 454 lookahead = (SBT_1S / 8); 455 else 456 lookahead = (SBT_1S / 2); 457 first = last = now; 458 first += (lookahead / 2); 459 last += lookahead; 460 last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); 461 lastb = callout_hash(last) - 1; 462 max = last; 463 464 /* 465 * Check if we wrapped around the entire wheel from the last scan. 466 * In case, we need to scan entirely the wheel for pending callouts. 467 */ 468 if (lastb - firstb >= callwheelsize) { 469 lastb = firstb + callwheelsize - 1; 470 if (nowb - firstb >= callwheelsize) 471 nowb = lastb; 472 } 473 474 /* Iterate callwheel from firstb to nowb and then up to lastb. */ 475 do { 476 sc = &cc->cc_callwheel[firstb & callwheelmask]; 477 tmp = LIST_FIRST(sc); 478 while (tmp != NULL) { 479 /* Run the callout if present time within allowed. */ 480 if (tmp->c_time <= now) { 481 /* 482 * Consumer told us the callout may be run 483 * directly from hardware interrupt context. 484 */ 485 if (tmp->c_iflags & CALLOUT_DIRECT) { 486 #ifdef CALLOUT_PROFILING 487 ++depth_dir; 488 #endif 489 cc_exec_next(cc) = 490 LIST_NEXT(tmp, c_links.le); 491 cc->cc_bucket = firstb & callwheelmask; 492 LIST_REMOVE(tmp, c_links.le); 493 softclock_call_cc(tmp, cc, 494 #ifdef CALLOUT_PROFILING 495 &mpcalls_dir, &lockcalls_dir, NULL, 496 #endif 497 1); 498 tmp = cc_exec_next(cc); 499 cc_exec_next(cc) = NULL; 500 } else { 501 tmpn = LIST_NEXT(tmp, c_links.le); 502 LIST_REMOVE(tmp, c_links.le); 503 TAILQ_INSERT_TAIL(&cc->cc_expireq, 504 tmp, c_links.tqe); 505 tmp->c_iflags |= CALLOUT_PROCESSED; 506 tmp = tmpn; 507 } 508 continue; 509 } 510 /* Skip events from distant future. */ 511 if (tmp->c_time >= max) 512 goto next; 513 /* 514 * Event minimal time is bigger than present maximal 515 * time, so it cannot be aggregated. 516 */ 517 if (tmp->c_time > last) { 518 lastb = nowb; 519 goto next; 520 } 521 /* Update first and last time, respecting this event. */ 522 if (tmp->c_time < first) 523 first = tmp->c_time; 524 tmp_max = tmp->c_time + tmp->c_precision; 525 if (tmp_max < last) 526 last = tmp_max; 527 next: 528 tmp = LIST_NEXT(tmp, c_links.le); 529 } 530 /* Proceed with the next bucket. */ 531 firstb++; 532 /* 533 * Stop if we looked after present time and found 534 * some event we can't execute at now. 535 * Stop if we looked far enough into the future. 536 */ 537 } while (((int)(firstb - lastb)) <= 0); 538 cc->cc_firstevent = last; 539 #ifndef NO_EVENTTIMERS 540 cpu_new_callout(curcpu, last, first); 541 #endif 542 #ifdef CALLOUT_PROFILING 543 avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8; 544 avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8; 545 avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8; 546 #endif 547 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 548 /* 549 * swi_sched acquires the thread lock, so we don't want to call it 550 * with cc_lock held; incorrect locking order. 551 */ 552 if (!TAILQ_EMPTY(&cc->cc_expireq)) 553 swi_sched(cc->cc_cookie, 0); 554 } 555 556 static struct callout_cpu * 557 callout_lock(struct callout *c) 558 { 559 struct callout_cpu *cc; 560 int cpu; 561 562 for (;;) { 563 cpu = c->c_cpu; 564 #ifdef SMP 565 if (cpu == CPUBLOCK) { 566 while (c->c_cpu == CPUBLOCK) 567 cpu_spinwait(); 568 continue; 569 } 570 #endif 571 cc = CC_CPU(cpu); 572 CC_LOCK(cc); 573 if (cpu == c->c_cpu) 574 break; 575 CC_UNLOCK(cc); 576 } 577 return (cc); 578 } 579 580 static void 581 callout_cc_add(struct callout *c, struct callout_cpu *cc, 582 sbintime_t sbt, sbintime_t precision, void (*func)(void *), 583 void *arg, int cpu, int flags) 584 { 585 int bucket; 586 587 CC_LOCK_ASSERT(cc); 588 if (sbt < cc->cc_lastscan) 589 sbt = cc->cc_lastscan; 590 c->c_arg = arg; 591 c->c_iflags |= CALLOUT_PENDING; 592 c->c_iflags &= ~CALLOUT_PROCESSED; 593 c->c_flags |= CALLOUT_ACTIVE; 594 if (flags & C_DIRECT_EXEC) 595 c->c_iflags |= CALLOUT_DIRECT; 596 c->c_func = func; 597 c->c_time = sbt; 598 c->c_precision = precision; 599 bucket = callout_get_bucket(c->c_time); 600 CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x", 601 c, (int)(c->c_precision >> 32), 602 (u_int)(c->c_precision & 0xffffffff)); 603 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); 604 if (cc->cc_bucket == bucket) 605 cc_exec_next(cc) = c; 606 #ifndef NO_EVENTTIMERS 607 /* 608 * Inform the eventtimers(4) subsystem there's a new callout 609 * that has been inserted, but only if really required. 610 */ 611 if (SBT_MAX - c->c_time < c->c_precision) 612 c->c_precision = SBT_MAX - c->c_time; 613 sbt = c->c_time + c->c_precision; 614 if (sbt < cc->cc_firstevent) { 615 cc->cc_firstevent = sbt; 616 cpu_new_callout(cpu, sbt, c->c_time); 617 } 618 #endif 619 } 620 621 static void 622 callout_cc_del(struct callout *c, struct callout_cpu *cc) 623 { 624 625 if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) == 0) 626 return; 627 c->c_func = NULL; 628 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 629 } 630 631 static void 632 softclock_call_cc(struct callout *c, struct callout_cpu *cc, 633 #ifdef CALLOUT_PROFILING 634 int *mpcalls, int *lockcalls, int *gcalls, 635 #endif 636 int direct) 637 { 638 struct rm_priotracker tracker; 639 void (*c_func)(void *); 640 void *c_arg; 641 struct lock_class *class; 642 struct lock_object *c_lock; 643 uintptr_t lock_status; 644 int c_iflags; 645 #ifdef SMP 646 struct callout_cpu *new_cc; 647 void (*new_func)(void *); 648 void *new_arg; 649 int flags, new_cpu; 650 sbintime_t new_prec, new_time; 651 #endif 652 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 653 sbintime_t sbt1, sbt2; 654 struct timespec ts2; 655 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 656 static timeout_t *lastfunc; 657 #endif 658 659 KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING, 660 ("softclock_call_cc: pend %p %x", c, c->c_iflags)); 661 KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE, 662 ("softclock_call_cc: act %p %x", c, c->c_flags)); 663 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; 664 lock_status = 0; 665 if (c->c_flags & CALLOUT_SHAREDLOCK) { 666 if (class == &lock_class_rm) 667 lock_status = (uintptr_t)&tracker; 668 else 669 lock_status = 1; 670 } 671 c_lock = c->c_lock; 672 c_func = c->c_func; 673 c_arg = c->c_arg; 674 c_iflags = c->c_iflags; 675 if (c->c_iflags & CALLOUT_LOCAL_ALLOC) 676 c->c_iflags = CALLOUT_LOCAL_ALLOC; 677 else 678 c->c_iflags &= ~CALLOUT_PENDING; 679 680 cc_exec_curr(cc, direct) = c; 681 cc_exec_cancel(cc, direct) = false; 682 CC_UNLOCK(cc); 683 if (c_lock != NULL) { 684 class->lc_lock(c_lock, lock_status); 685 /* 686 * The callout may have been cancelled 687 * while we switched locks. 688 */ 689 if (cc_exec_cancel(cc, direct)) { 690 class->lc_unlock(c_lock); 691 goto skip; 692 } 693 /* The callout cannot be stopped now. */ 694 cc_exec_cancel(cc, direct) = true; 695 if (c_lock == &Giant.lock_object) { 696 #ifdef CALLOUT_PROFILING 697 (*gcalls)++; 698 #endif 699 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", 700 c, c_func, c_arg); 701 } else { 702 #ifdef CALLOUT_PROFILING 703 (*lockcalls)++; 704 #endif 705 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", 706 c, c_func, c_arg); 707 } 708 } else { 709 #ifdef CALLOUT_PROFILING 710 (*mpcalls)++; 711 #endif 712 CTR3(KTR_CALLOUT, "callout %p func %p arg %p", 713 c, c_func, c_arg); 714 } 715 KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running", 716 "func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct); 717 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 718 sbt1 = sbinuptime(); 719 #endif 720 THREAD_NO_SLEEPING(); 721 SDT_PROBE1(callout_execute, kernel, , callout__start, c); 722 c_func(c_arg); 723 SDT_PROBE1(callout_execute, kernel, , callout__end, c); 724 THREAD_SLEEPING_OK(); 725 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 726 sbt2 = sbinuptime(); 727 sbt2 -= sbt1; 728 if (sbt2 > maxdt) { 729 if (lastfunc != c_func || sbt2 > maxdt * 2) { 730 ts2 = sbttots(sbt2); 731 printf( 732 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 733 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); 734 } 735 maxdt = sbt2; 736 lastfunc = c_func; 737 } 738 #endif 739 KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle"); 740 CTR1(KTR_CALLOUT, "callout %p finished", c); 741 if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0) 742 class->lc_unlock(c_lock); 743 skip: 744 CC_LOCK(cc); 745 KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr")); 746 cc_exec_curr(cc, direct) = NULL; 747 if (cc_exec_waiting(cc, direct)) { 748 /* 749 * There is someone waiting for the 750 * callout to complete. 751 * If the callout was scheduled for 752 * migration just cancel it. 753 */ 754 if (cc_cce_migrating(cc, direct)) { 755 cc_cce_cleanup(cc, direct); 756 757 /* 758 * It should be assert here that the callout is not 759 * destroyed but that is not easy. 760 */ 761 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 762 } 763 cc_exec_waiting(cc, direct) = false; 764 CC_UNLOCK(cc); 765 wakeup(&cc_exec_waiting(cc, direct)); 766 CC_LOCK(cc); 767 } else if (cc_cce_migrating(cc, direct)) { 768 KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0, 769 ("Migrating legacy callout %p", c)); 770 #ifdef SMP 771 /* 772 * If the callout was scheduled for 773 * migration just perform it now. 774 */ 775 new_cpu = cc_migration_cpu(cc, direct); 776 new_time = cc_migration_time(cc, direct); 777 new_prec = cc_migration_prec(cc, direct); 778 new_func = cc_migration_func(cc, direct); 779 new_arg = cc_migration_arg(cc, direct); 780 cc_cce_cleanup(cc, direct); 781 782 /* 783 * It should be assert here that the callout is not destroyed 784 * but that is not easy. 785 * 786 * As first thing, handle deferred callout stops. 787 */ 788 if (!callout_migrating(c)) { 789 CTR3(KTR_CALLOUT, 790 "deferred cancelled %p func %p arg %p", 791 c, new_func, new_arg); 792 callout_cc_del(c, cc); 793 return; 794 } 795 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 796 797 new_cc = callout_cpu_switch(c, cc, new_cpu); 798 flags = (direct) ? C_DIRECT_EXEC : 0; 799 callout_cc_add(c, new_cc, new_time, new_prec, new_func, 800 new_arg, new_cpu, flags); 801 CC_UNLOCK(new_cc); 802 CC_LOCK(cc); 803 #else 804 panic("migration should not happen"); 805 #endif 806 } 807 /* 808 * If the current callout is locally allocated (from 809 * timeout(9)) then put it on the freelist. 810 * 811 * Note: we need to check the cached copy of c_iflags because 812 * if it was not local, then it's not safe to deref the 813 * callout pointer. 814 */ 815 KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0 || 816 c->c_iflags == CALLOUT_LOCAL_ALLOC, 817 ("corrupted callout")); 818 if (c_iflags & CALLOUT_LOCAL_ALLOC) 819 callout_cc_del(c, cc); 820 } 821 822 /* 823 * The callout mechanism is based on the work of Adam M. Costello and 824 * George Varghese, published in a technical report entitled "Redesigning 825 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 826 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 827 * used in this implementation was published by G. Varghese and T. Lauck in 828 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 829 * the Efficient Implementation of a Timer Facility" in the Proceedings of 830 * the 11th ACM Annual Symposium on Operating Systems Principles, 831 * Austin, Texas Nov 1987. 832 */ 833 834 /* 835 * Software (low priority) clock interrupt. 836 * Run periodic events from timeout queue. 837 */ 838 void 839 softclock(void *arg) 840 { 841 struct callout_cpu *cc; 842 struct callout *c; 843 #ifdef CALLOUT_PROFILING 844 int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0; 845 #endif 846 847 cc = (struct callout_cpu *)arg; 848 CC_LOCK(cc); 849 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { 850 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 851 softclock_call_cc(c, cc, 852 #ifdef CALLOUT_PROFILING 853 &mpcalls, &lockcalls, &gcalls, 854 #endif 855 0); 856 #ifdef CALLOUT_PROFILING 857 ++depth; 858 #endif 859 } 860 #ifdef CALLOUT_PROFILING 861 avg_depth += (depth * 1000 - avg_depth) >> 8; 862 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 863 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 864 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 865 #endif 866 CC_UNLOCK(cc); 867 } 868 869 /* 870 * timeout -- 871 * Execute a function after a specified length of time. 872 * 873 * untimeout -- 874 * Cancel previous timeout function call. 875 * 876 * callout_handle_init -- 877 * Initialize a handle so that using it with untimeout is benign. 878 * 879 * See AT&T BCI Driver Reference Manual for specification. This 880 * implementation differs from that one in that although an 881 * identification value is returned from timeout, the original 882 * arguments to timeout as well as the identifier are used to 883 * identify entries for untimeout. 884 */ 885 struct callout_handle 886 timeout(timeout_t *ftn, void *arg, int to_ticks) 887 { 888 struct callout_cpu *cc; 889 struct callout *new; 890 struct callout_handle handle; 891 892 cc = CC_CPU(timeout_cpu); 893 CC_LOCK(cc); 894 /* Fill in the next free callout structure. */ 895 new = SLIST_FIRST(&cc->cc_callfree); 896 if (new == NULL) 897 /* XXX Attempt to malloc first */ 898 panic("timeout table full"); 899 SLIST_REMOVE_HEAD(&cc->cc_callfree, c_links.sle); 900 callout_reset(new, to_ticks, ftn, arg); 901 handle.callout = new; 902 CC_UNLOCK(cc); 903 904 return (handle); 905 } 906 907 void 908 untimeout(timeout_t *ftn, void *arg, struct callout_handle handle) 909 { 910 struct callout_cpu *cc; 911 912 /* 913 * Check for a handle that was initialized 914 * by callout_handle_init, but never used 915 * for a real timeout. 916 */ 917 if (handle.callout == NULL) 918 return; 919 920 cc = callout_lock(handle.callout); 921 if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) 922 callout_stop(handle.callout); 923 CC_UNLOCK(cc); 924 } 925 926 void 927 callout_handle_init(struct callout_handle *handle) 928 { 929 handle->callout = NULL; 930 } 931 932 /* 933 * New interface; clients allocate their own callout structures. 934 * 935 * callout_reset() - establish or change a timeout 936 * callout_stop() - disestablish a timeout 937 * callout_init() - initialize a callout structure so that it can 938 * safely be passed to callout_reset() and callout_stop() 939 * 940 * <sys/callout.h> defines three convenience macros: 941 * 942 * callout_active() - returns truth if callout has not been stopped, 943 * drained, or deactivated since the last time the callout was 944 * reset. 945 * callout_pending() - returns truth if callout is still waiting for timeout 946 * callout_deactivate() - marks the callout as having been serviced 947 */ 948 int 949 callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t precision, 950 void (*ftn)(void *), void *arg, int cpu, int flags) 951 { 952 sbintime_t to_sbt, pr; 953 struct callout_cpu *cc; 954 int cancelled, direct; 955 int ignore_cpu=0; 956 957 cancelled = 0; 958 if (cpu == -1) { 959 ignore_cpu = 1; 960 } else if ((cpu >= MAXCPU) || 961 ((CC_CPU(cpu))->cc_inited == 0)) { 962 /* Invalid CPU spec */ 963 panic("Invalid CPU in callout %d", cpu); 964 } 965 if (flags & C_ABSOLUTE) { 966 to_sbt = sbt; 967 } else { 968 if ((flags & C_HARDCLOCK) && (sbt < tick_sbt)) 969 sbt = tick_sbt; 970 if ((flags & C_HARDCLOCK) || 971 #ifdef NO_EVENTTIMERS 972 sbt >= sbt_timethreshold) { 973 to_sbt = getsbinuptime(); 974 975 /* Add safety belt for the case of hz > 1000. */ 976 to_sbt += tc_tick_sbt - tick_sbt; 977 #else 978 sbt >= sbt_tickthreshold) { 979 /* 980 * Obtain the time of the last hardclock() call on 981 * this CPU directly from the kern_clocksource.c. 982 * This value is per-CPU, but it is equal for all 983 * active ones. 984 */ 985 #ifdef __LP64__ 986 to_sbt = DPCPU_GET(hardclocktime); 987 #else 988 spinlock_enter(); 989 to_sbt = DPCPU_GET(hardclocktime); 990 spinlock_exit(); 991 #endif 992 #endif 993 if ((flags & C_HARDCLOCK) == 0) 994 to_sbt += tick_sbt; 995 } else 996 to_sbt = sbinuptime(); 997 if (SBT_MAX - to_sbt < sbt) 998 to_sbt = SBT_MAX; 999 else 1000 to_sbt += sbt; 1001 pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : 1002 sbt >> C_PRELGET(flags)); 1003 if (pr > precision) 1004 precision = pr; 1005 } 1006 /* 1007 * This flag used to be added by callout_cc_add, but the 1008 * first time you call this we could end up with the 1009 * wrong direct flag if we don't do it before we add. 1010 */ 1011 if (flags & C_DIRECT_EXEC) { 1012 direct = 1; 1013 } else { 1014 direct = 0; 1015 } 1016 KASSERT(!direct || c->c_lock == NULL, 1017 ("%s: direct callout %p has lock", __func__, c)); 1018 cc = callout_lock(c); 1019 /* 1020 * Don't allow migration of pre-allocated callouts lest they 1021 * become unbalanced or handle the case where the user does 1022 * not care. 1023 */ 1024 if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) || 1025 ignore_cpu) { 1026 cpu = c->c_cpu; 1027 } 1028 1029 if (cc_exec_curr(cc, direct) == c) { 1030 /* 1031 * We're being asked to reschedule a callout which is 1032 * currently in progress. If there is a lock then we 1033 * can cancel the callout if it has not really started. 1034 */ 1035 if (c->c_lock != NULL && !cc_exec_cancel(cc, direct)) 1036 cancelled = cc_exec_cancel(cc, direct) = true; 1037 if (cc_exec_waiting(cc, direct)) { 1038 /* 1039 * Someone has called callout_drain to kill this 1040 * callout. Don't reschedule. 1041 */ 1042 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 1043 cancelled ? "cancelled" : "failed to cancel", 1044 c, c->c_func, c->c_arg); 1045 CC_UNLOCK(cc); 1046 return (cancelled); 1047 } 1048 #ifdef SMP 1049 if (callout_migrating(c)) { 1050 /* 1051 * This only occurs when a second callout_reset_sbt_on 1052 * is made after a previous one moved it into 1053 * deferred migration (below). Note we do *not* change 1054 * the prev_cpu even though the previous target may 1055 * be different. 1056 */ 1057 cc_migration_cpu(cc, direct) = cpu; 1058 cc_migration_time(cc, direct) = to_sbt; 1059 cc_migration_prec(cc, direct) = precision; 1060 cc_migration_func(cc, direct) = ftn; 1061 cc_migration_arg(cc, direct) = arg; 1062 cancelled = 1; 1063 CC_UNLOCK(cc); 1064 return (cancelled); 1065 } 1066 #endif 1067 } 1068 if (c->c_iflags & CALLOUT_PENDING) { 1069 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1070 if (cc_exec_next(cc) == c) 1071 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1072 LIST_REMOVE(c, c_links.le); 1073 } else { 1074 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1075 } 1076 cancelled = 1; 1077 c->c_iflags &= ~ CALLOUT_PENDING; 1078 c->c_flags &= ~ CALLOUT_ACTIVE; 1079 } 1080 1081 #ifdef SMP 1082 /* 1083 * If the callout must migrate try to perform it immediately. 1084 * If the callout is currently running, just defer the migration 1085 * to a more appropriate moment. 1086 */ 1087 if (c->c_cpu != cpu) { 1088 if (cc_exec_curr(cc, direct) == c) { 1089 /* 1090 * Pending will have been removed since we are 1091 * actually executing the callout on another 1092 * CPU. That callout should be waiting on the 1093 * lock the caller holds. If we set both 1094 * active/and/pending after we return and the 1095 * lock on the executing callout proceeds, it 1096 * will then see pending is true and return. 1097 * At the return from the actual callout execution 1098 * the migration will occur in softclock_call_cc 1099 * and this new callout will be placed on the 1100 * new CPU via a call to callout_cpu_switch() which 1101 * will get the lock on the right CPU followed 1102 * by a call callout_cc_add() which will add it there. 1103 * (see above in softclock_call_cc()). 1104 */ 1105 cc_migration_cpu(cc, direct) = cpu; 1106 cc_migration_time(cc, direct) = to_sbt; 1107 cc_migration_prec(cc, direct) = precision; 1108 cc_migration_func(cc, direct) = ftn; 1109 cc_migration_arg(cc, direct) = arg; 1110 c->c_iflags |= (CALLOUT_DFRMIGRATION | CALLOUT_PENDING); 1111 c->c_flags |= CALLOUT_ACTIVE; 1112 CTR6(KTR_CALLOUT, 1113 "migration of %p func %p arg %p in %d.%08x to %u deferred", 1114 c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1115 (u_int)(to_sbt & 0xffffffff), cpu); 1116 CC_UNLOCK(cc); 1117 return (cancelled); 1118 } 1119 cc = callout_cpu_switch(c, cc, cpu); 1120 } 1121 #endif 1122 1123 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags); 1124 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", 1125 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1126 (u_int)(to_sbt & 0xffffffff)); 1127 CC_UNLOCK(cc); 1128 1129 return (cancelled); 1130 } 1131 1132 /* 1133 * Common idioms that can be optimized in the future. 1134 */ 1135 int 1136 callout_schedule_on(struct callout *c, int to_ticks, int cpu) 1137 { 1138 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 1139 } 1140 1141 int 1142 callout_schedule(struct callout *c, int to_ticks) 1143 { 1144 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 1145 } 1146 1147 int 1148 _callout_stop_safe(struct callout *c, int safe) 1149 { 1150 struct callout_cpu *cc, *old_cc; 1151 struct lock_class *class; 1152 int direct, sq_locked, use_lock; 1153 int not_on_a_list; 1154 1155 if (safe) 1156 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock, 1157 "calling %s", __func__); 1158 1159 /* 1160 * Some old subsystems don't hold Giant while running a callout_stop(), 1161 * so just discard this check for the moment. 1162 */ 1163 if (!safe && c->c_lock != NULL) { 1164 if (c->c_lock == &Giant.lock_object) 1165 use_lock = mtx_owned(&Giant); 1166 else { 1167 use_lock = 1; 1168 class = LOCK_CLASS(c->c_lock); 1169 class->lc_assert(c->c_lock, LA_XLOCKED); 1170 } 1171 } else 1172 use_lock = 0; 1173 if (c->c_iflags & CALLOUT_DIRECT) { 1174 direct = 1; 1175 } else { 1176 direct = 0; 1177 } 1178 sq_locked = 0; 1179 old_cc = NULL; 1180 again: 1181 cc = callout_lock(c); 1182 1183 if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) == 1184 (CALLOUT_DFRMIGRATION | CALLOUT_PENDING) && 1185 ((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) { 1186 /* 1187 * Special case where this slipped in while we 1188 * were migrating *as* the callout is about to 1189 * execute. The caller probably holds the lock 1190 * the callout wants. 1191 * 1192 * Get rid of the migration first. Then set 1193 * the flag that tells this code *not* to 1194 * try to remove it from any lists (its not 1195 * on one yet). When the callout wheel runs, 1196 * it will ignore this callout. 1197 */ 1198 c->c_iflags &= ~CALLOUT_PENDING; 1199 c->c_flags &= ~CALLOUT_ACTIVE; 1200 not_on_a_list = 1; 1201 } else { 1202 not_on_a_list = 0; 1203 } 1204 1205 /* 1206 * If the callout was migrating while the callout cpu lock was 1207 * dropped, just drop the sleepqueue lock and check the states 1208 * again. 1209 */ 1210 if (sq_locked != 0 && cc != old_cc) { 1211 #ifdef SMP 1212 CC_UNLOCK(cc); 1213 sleepq_release(&cc_exec_waiting(old_cc, direct)); 1214 sq_locked = 0; 1215 old_cc = NULL; 1216 goto again; 1217 #else 1218 panic("migration should not happen"); 1219 #endif 1220 } 1221 1222 /* 1223 * If the callout isn't pending, it's not on the queue, so 1224 * don't attempt to remove it from the queue. We can try to 1225 * stop it by other means however. 1226 */ 1227 if (!(c->c_iflags & CALLOUT_PENDING)) { 1228 c->c_flags &= ~CALLOUT_ACTIVE; 1229 1230 /* 1231 * If it wasn't on the queue and it isn't the current 1232 * callout, then we can't stop it, so just bail. 1233 */ 1234 if (cc_exec_curr(cc, direct) != c) { 1235 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1236 c, c->c_func, c->c_arg); 1237 CC_UNLOCK(cc); 1238 if (sq_locked) 1239 sleepq_release(&cc_exec_waiting(cc, direct)); 1240 return (0); 1241 } 1242 1243 if (safe) { 1244 /* 1245 * The current callout is running (or just 1246 * about to run) and blocking is allowed, so 1247 * just wait for the current invocation to 1248 * finish. 1249 */ 1250 while (cc_exec_curr(cc, direct) == c) { 1251 /* 1252 * Use direct calls to sleepqueue interface 1253 * instead of cv/msleep in order to avoid 1254 * a LOR between cc_lock and sleepqueue 1255 * chain spinlocks. This piece of code 1256 * emulates a msleep_spin() call actually. 1257 * 1258 * If we already have the sleepqueue chain 1259 * locked, then we can safely block. If we 1260 * don't already have it locked, however, 1261 * we have to drop the cc_lock to lock 1262 * it. This opens several races, so we 1263 * restart at the beginning once we have 1264 * both locks. If nothing has changed, then 1265 * we will end up back here with sq_locked 1266 * set. 1267 */ 1268 if (!sq_locked) { 1269 CC_UNLOCK(cc); 1270 sleepq_lock( 1271 &cc_exec_waiting(cc, direct)); 1272 sq_locked = 1; 1273 old_cc = cc; 1274 goto again; 1275 } 1276 1277 /* 1278 * Migration could be cancelled here, but 1279 * as long as it is still not sure when it 1280 * will be packed up, just let softclock() 1281 * take care of it. 1282 */ 1283 cc_exec_waiting(cc, direct) = true; 1284 DROP_GIANT(); 1285 CC_UNLOCK(cc); 1286 sleepq_add( 1287 &cc_exec_waiting(cc, direct), 1288 &cc->cc_lock.lock_object, "codrain", 1289 SLEEPQ_SLEEP, 0); 1290 sleepq_wait( 1291 &cc_exec_waiting(cc, direct), 1292 0); 1293 sq_locked = 0; 1294 old_cc = NULL; 1295 1296 /* Reacquire locks previously released. */ 1297 PICKUP_GIANT(); 1298 CC_LOCK(cc); 1299 } 1300 } else if (use_lock && 1301 !cc_exec_cancel(cc, direct)) { 1302 1303 /* 1304 * The current callout is waiting for its 1305 * lock which we hold. Cancel the callout 1306 * and return. After our caller drops the 1307 * lock, the callout will be skipped in 1308 * softclock(). 1309 */ 1310 cc_exec_cancel(cc, direct) = true; 1311 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1312 c, c->c_func, c->c_arg); 1313 KASSERT(!cc_cce_migrating(cc, direct), 1314 ("callout wrongly scheduled for migration")); 1315 if (callout_migrating(c)) { 1316 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1317 #ifdef SMP 1318 cc_migration_cpu(cc, direct) = CPUBLOCK; 1319 cc_migration_time(cc, direct) = 0; 1320 cc_migration_prec(cc, direct) = 0; 1321 cc_migration_func(cc, direct) = NULL; 1322 cc_migration_arg(cc, direct) = NULL; 1323 #endif 1324 } 1325 CC_UNLOCK(cc); 1326 KASSERT(!sq_locked, ("sleepqueue chain locked")); 1327 return (1); 1328 } else if (callout_migrating(c)) { 1329 /* 1330 * The callout is currently being serviced 1331 * and the "next" callout is scheduled at 1332 * its completion with a migration. We remove 1333 * the migration flag so it *won't* get rescheduled, 1334 * but we can't stop the one thats running so 1335 * we return 0. 1336 */ 1337 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1338 #ifdef SMP 1339 /* 1340 * We can't call cc_cce_cleanup here since 1341 * if we do it will remove .ce_curr and 1342 * its still running. This will prevent a 1343 * reschedule of the callout when the 1344 * execution completes. 1345 */ 1346 cc_migration_cpu(cc, direct) = CPUBLOCK; 1347 cc_migration_time(cc, direct) = 0; 1348 cc_migration_prec(cc, direct) = 0; 1349 cc_migration_func(cc, direct) = NULL; 1350 cc_migration_arg(cc, direct) = NULL; 1351 #endif 1352 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 1353 c, c->c_func, c->c_arg); 1354 CC_UNLOCK(cc); 1355 return (0); 1356 } 1357 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1358 c, c->c_func, c->c_arg); 1359 CC_UNLOCK(cc); 1360 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 1361 return (0); 1362 } 1363 if (sq_locked) 1364 sleepq_release(&cc_exec_waiting(cc, direct)); 1365 1366 c->c_iflags &= ~CALLOUT_PENDING; 1367 c->c_flags &= ~CALLOUT_ACTIVE; 1368 1369 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1370 c, c->c_func, c->c_arg); 1371 if (not_on_a_list == 0) { 1372 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1373 if (cc_exec_next(cc) == c) 1374 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1375 LIST_REMOVE(c, c_links.le); 1376 } else { 1377 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1378 } 1379 } 1380 callout_cc_del(c, cc); 1381 CC_UNLOCK(cc); 1382 return (1); 1383 } 1384 1385 void 1386 callout_init(struct callout *c, int mpsafe) 1387 { 1388 bzero(c, sizeof *c); 1389 if (mpsafe) { 1390 c->c_lock = NULL; 1391 c->c_iflags = CALLOUT_RETURNUNLOCKED; 1392 } else { 1393 c->c_lock = &Giant.lock_object; 1394 c->c_iflags = 0; 1395 } 1396 c->c_cpu = timeout_cpu; 1397 } 1398 1399 void 1400 _callout_init_lock(struct callout *c, struct lock_object *lock, int flags) 1401 { 1402 bzero(c, sizeof *c); 1403 c->c_lock = lock; 1404 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1405 ("callout_init_lock: bad flags %d", flags)); 1406 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1407 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1408 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & 1409 (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class", 1410 __func__)); 1411 c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1412 c->c_cpu = timeout_cpu; 1413 } 1414 1415 #ifdef APM_FIXUP_CALLTODO 1416 /* 1417 * Adjust the kernel calltodo timeout list. This routine is used after 1418 * an APM resume to recalculate the calltodo timer list values with the 1419 * number of hz's we have been sleeping. The next hardclock() will detect 1420 * that there are fired timers and run softclock() to execute them. 1421 * 1422 * Please note, I have not done an exhaustive analysis of what code this 1423 * might break. I am motivated to have my select()'s and alarm()'s that 1424 * have expired during suspend firing upon resume so that the applications 1425 * which set the timer can do the maintanence the timer was for as close 1426 * as possible to the originally intended time. Testing this code for a 1427 * week showed that resuming from a suspend resulted in 22 to 25 timers 1428 * firing, which seemed independant on whether the suspend was 2 hours or 1429 * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu> 1430 */ 1431 void 1432 adjust_timeout_calltodo(struct timeval *time_change) 1433 { 1434 register struct callout *p; 1435 unsigned long delta_ticks; 1436 1437 /* 1438 * How many ticks were we asleep? 1439 * (stolen from tvtohz()). 1440 */ 1441 1442 /* Don't do anything */ 1443 if (time_change->tv_sec < 0) 1444 return; 1445 else if (time_change->tv_sec <= LONG_MAX / 1000000) 1446 delta_ticks = (time_change->tv_sec * 1000000 + 1447 time_change->tv_usec + (tick - 1)) / tick + 1; 1448 else if (time_change->tv_sec <= LONG_MAX / hz) 1449 delta_ticks = time_change->tv_sec * hz + 1450 (time_change->tv_usec + (tick - 1)) / tick + 1; 1451 else 1452 delta_ticks = LONG_MAX; 1453 1454 if (delta_ticks > INT_MAX) 1455 delta_ticks = INT_MAX; 1456 1457 /* 1458 * Now rip through the timer calltodo list looking for timers 1459 * to expire. 1460 */ 1461 1462 /* don't collide with softclock() */ 1463 CC_LOCK(cc); 1464 for (p = calltodo.c_next; p != NULL; p = p->c_next) { 1465 p->c_time -= delta_ticks; 1466 1467 /* Break if the timer had more time on it than delta_ticks */ 1468 if (p->c_time > 0) 1469 break; 1470 1471 /* take back the ticks the timer didn't use (p->c_time <= 0) */ 1472 delta_ticks = -p->c_time; 1473 } 1474 CC_UNLOCK(cc); 1475 1476 return; 1477 } 1478 #endif /* APM_FIXUP_CALLTODO */ 1479 1480 static int 1481 flssbt(sbintime_t sbt) 1482 { 1483 1484 sbt += (uint64_t)sbt >> 1; 1485 if (sizeof(long) >= sizeof(sbintime_t)) 1486 return (flsl(sbt)); 1487 if (sbt >= SBT_1S) 1488 return (flsl(((uint64_t)sbt) >> 32) + 32); 1489 return (flsl(sbt)); 1490 } 1491 1492 /* 1493 * Dump immediate statistic snapshot of the scheduled callouts. 1494 */ 1495 static int 1496 sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1497 { 1498 struct callout *tmp; 1499 struct callout_cpu *cc; 1500 struct callout_list *sc; 1501 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; 1502 int ct[64], cpr[64], ccpbk[32]; 1503 int error, val, i, count, tcum, pcum, maxc, c, medc; 1504 #ifdef SMP 1505 int cpu; 1506 #endif 1507 1508 val = 0; 1509 error = sysctl_handle_int(oidp, &val, 0, req); 1510 if (error != 0 || req->newptr == NULL) 1511 return (error); 1512 count = maxc = 0; 1513 st = spr = maxt = maxpr = 0; 1514 bzero(ccpbk, sizeof(ccpbk)); 1515 bzero(ct, sizeof(ct)); 1516 bzero(cpr, sizeof(cpr)); 1517 now = sbinuptime(); 1518 #ifdef SMP 1519 CPU_FOREACH(cpu) { 1520 cc = CC_CPU(cpu); 1521 #else 1522 cc = CC_CPU(timeout_cpu); 1523 #endif 1524 CC_LOCK(cc); 1525 for (i = 0; i < callwheelsize; i++) { 1526 sc = &cc->cc_callwheel[i]; 1527 c = 0; 1528 LIST_FOREACH(tmp, sc, c_links.le) { 1529 c++; 1530 t = tmp->c_time - now; 1531 if (t < 0) 1532 t = 0; 1533 st += t / SBT_1US; 1534 spr += tmp->c_precision / SBT_1US; 1535 if (t > maxt) 1536 maxt = t; 1537 if (tmp->c_precision > maxpr) 1538 maxpr = tmp->c_precision; 1539 ct[flssbt(t)]++; 1540 cpr[flssbt(tmp->c_precision)]++; 1541 } 1542 if (c > maxc) 1543 maxc = c; 1544 ccpbk[fls(c + c / 2)]++; 1545 count += c; 1546 } 1547 CC_UNLOCK(cc); 1548 #ifdef SMP 1549 } 1550 #endif 1551 1552 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1553 tcum += ct[i]; 1554 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1555 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) 1556 pcum += cpr[i]; 1557 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1558 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1559 c += ccpbk[i]; 1560 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1561 1562 printf("Scheduled callouts statistic snapshot:\n"); 1563 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1564 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1565 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1566 medc, 1567 count / callwheelsize / mp_ncpus, 1568 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1569 maxc); 1570 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1571 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1572 (st / count) / 1000000, (st / count) % 1000000, 1573 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); 1574 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1575 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, 1576 (spr / count) / 1000000, (spr / count) % 1000000, 1577 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); 1578 printf(" Distribution: \tbuckets\t time\t tcum\t" 1579 " prec\t pcum\n"); 1580 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1581 if (ct[i] == 0 && cpr[i] == 0) 1582 continue; 1583 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1584 tcum += ct[i]; 1585 pcum += cpr[i]; 1586 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", 1587 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1588 i - 1 - (32 - CC_HASH_SHIFT), 1589 ct[i], tcum, cpr[i], pcum); 1590 } 1591 return (error); 1592 } 1593 SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1594 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1595 0, 0, sysctl_kern_callout_stat, "I", 1596 "Dump immediate statistic snapshot of the scheduled callouts"); 1597