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