1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include "opt_callout_profiling.h" 43 #include "opt_ddb.h" 44 #if defined(__arm__) 45 #include "opt_timer.h" 46 #endif 47 #include "opt_rss.h" 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/bus.h> 52 #include <sys/callout.h> 53 #include <sys/domainset.h> 54 #include <sys/file.h> 55 #include <sys/interrupt.h> 56 #include <sys/kernel.h> 57 #include <sys/ktr.h> 58 #include <sys/lock.h> 59 #include <sys/malloc.h> 60 #include <sys/mutex.h> 61 #include <sys/proc.h> 62 #include <sys/sdt.h> 63 #include <sys/sleepqueue.h> 64 #include <sys/sysctl.h> 65 #include <sys/smp.h> 66 67 #ifdef DDB 68 #include <ddb/ddb.h> 69 #include <ddb/db_sym.h> 70 #include <machine/_inttypes.h> 71 #endif 72 73 #ifdef SMP 74 #include <machine/cpu.h> 75 #endif 76 77 #ifndef NO_EVENTTIMERS 78 DPCPU_DECLARE(sbintime_t, hardclocktime); 79 #endif 80 81 SDT_PROVIDER_DEFINE(callout_execute); 82 SDT_PROBE_DEFINE1(callout_execute, , , callout__start, "struct callout *"); 83 SDT_PROBE_DEFINE1(callout_execute, , , callout__end, "struct callout *"); 84 85 #ifdef CALLOUT_PROFILING 86 static int avg_depth; 87 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, 88 "Average number of items examined per softclock call. Units = 1/1000"); 89 static int avg_gcalls; 90 SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, 91 "Average number of Giant callouts made per softclock call. Units = 1/1000"); 92 static int avg_lockcalls; 93 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0, 94 "Average number of lock callouts made per softclock call. Units = 1/1000"); 95 static int avg_mpcalls; 96 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, 97 "Average number of MP callouts made per softclock call. Units = 1/1000"); 98 static int avg_depth_dir; 99 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0, 100 "Average number of direct callouts examined per callout_process call. " 101 "Units = 1/1000"); 102 static int avg_lockcalls_dir; 103 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD, 104 &avg_lockcalls_dir, 0, "Average number of lock direct callouts made per " 105 "callout_process call. Units = 1/1000"); 106 static int avg_mpcalls_dir; 107 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir, 108 0, "Average number of MP direct callouts made per callout_process call. " 109 "Units = 1/1000"); 110 #endif 111 112 static int ncallout; 113 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &ncallout, 0, 114 "Number of entries in callwheel and size of timeout() preallocation"); 115 116 #ifdef RSS 117 static int pin_default_swi = 1; 118 static int pin_pcpu_swi = 1; 119 #else 120 static int pin_default_swi = 0; 121 static int pin_pcpu_swi = 0; 122 #endif 123 124 SYSCTL_INT(_kern, OID_AUTO, pin_default_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_default_swi, 125 0, "Pin the default (non-per-cpu) swi (shared with PCPU 0 swi)"); 126 SYSCTL_INT(_kern, OID_AUTO, pin_pcpu_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_pcpu_swi, 127 0, "Pin the per-CPU swis (except PCPU 0, which is also default"); 128 129 /* 130 * TODO: 131 * allocate more timeout table slots when table overflows. 132 */ 133 u_int callwheelsize, callwheelmask; 134 135 /* 136 * The callout cpu exec entities represent informations necessary for 137 * describing the state of callouts currently running on the CPU and the ones 138 * necessary for migrating callouts to the new callout cpu. In particular, 139 * the first entry of the array cc_exec_entity holds informations for callout 140 * running in SWI thread context, while the second one holds informations 141 * for callout running directly from hardware interrupt context. 142 * The cached informations are very important for deferring migration when 143 * the migrating callout is already running. 144 */ 145 struct cc_exec { 146 struct callout *cc_curr; 147 void (*cc_drain)(void *); 148 void *cc_last_func; 149 void *cc_last_arg; 150 #ifdef SMP 151 void (*ce_migration_func)(void *); 152 void *ce_migration_arg; 153 sbintime_t ce_migration_time; 154 sbintime_t ce_migration_prec; 155 int ce_migration_cpu; 156 #endif 157 bool cc_cancel; 158 bool cc_waiting; 159 }; 160 161 /* 162 * There is one struct callout_cpu per cpu, holding all relevant 163 * state for the callout processing thread on the individual CPU. 164 */ 165 struct callout_cpu { 166 struct mtx_padalign cc_lock; 167 struct cc_exec cc_exec_entity[2]; 168 struct callout *cc_next; 169 struct callout *cc_callout; 170 struct callout_list *cc_callwheel; 171 struct callout_tailq cc_expireq; 172 struct callout_slist cc_callfree; 173 sbintime_t cc_firstevent; 174 sbintime_t cc_lastscan; 175 void *cc_cookie; 176 u_int cc_bucket; 177 u_int cc_inited; 178 char cc_ktr_event_name[20]; 179 }; 180 181 #define callout_migrating(c) ((c)->c_iflags & CALLOUT_DFRMIGRATION) 182 183 #define cc_exec_curr(cc, dir) cc->cc_exec_entity[dir].cc_curr 184 #define cc_exec_last_func(cc, dir) cc->cc_exec_entity[dir].cc_last_func 185 #define cc_exec_last_arg(cc, dir) cc->cc_exec_entity[dir].cc_last_arg 186 #define cc_exec_drain(cc, dir) cc->cc_exec_entity[dir].cc_drain 187 #define cc_exec_next(cc) cc->cc_next 188 #define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel 189 #define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting 190 #ifdef SMP 191 #define cc_migration_func(cc, dir) cc->cc_exec_entity[dir].ce_migration_func 192 #define cc_migration_arg(cc, dir) cc->cc_exec_entity[dir].ce_migration_arg 193 #define cc_migration_cpu(cc, dir) cc->cc_exec_entity[dir].ce_migration_cpu 194 #define cc_migration_time(cc, dir) cc->cc_exec_entity[dir].ce_migration_time 195 #define cc_migration_prec(cc, dir) cc->cc_exec_entity[dir].ce_migration_prec 196 197 struct callout_cpu cc_cpu[MAXCPU]; 198 #define CPUBLOCK MAXCPU 199 #define CC_CPU(cpu) (&cc_cpu[(cpu)]) 200 #define CC_SELF() CC_CPU(PCPU_GET(cpuid)) 201 #else 202 struct callout_cpu cc_cpu; 203 #define CC_CPU(cpu) &cc_cpu 204 #define CC_SELF() &cc_cpu 205 #endif 206 #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) 207 #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) 208 #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) 209 210 static int timeout_cpu; 211 212 static void callout_cpu_init(struct callout_cpu *cc, int cpu); 213 static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, 214 #ifdef CALLOUT_PROFILING 215 int *mpcalls, int *lockcalls, int *gcalls, 216 #endif 217 int direct); 218 219 static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); 220 221 /** 222 * Locked by cc_lock: 223 * cc_curr - If a callout is in progress, it is cc_curr. 224 * If cc_curr is non-NULL, threads waiting in 225 * callout_drain() will be woken up as soon as the 226 * relevant callout completes. 227 * cc_cancel - Changing to 1 with both callout_lock and cc_lock held 228 * guarantees that the current callout will not run. 229 * The softclock() function sets this to 0 before it 230 * drops callout_lock to acquire c_lock, and it calls 231 * the handler only if curr_cancelled is still 0 after 232 * cc_lock is successfully acquired. 233 * cc_waiting - If a thread is waiting in callout_drain(), then 234 * callout_wait is nonzero. Set only when 235 * cc_curr is non-NULL. 236 */ 237 238 /* 239 * Resets the execution entity tied to a specific callout cpu. 240 */ 241 static void 242 cc_cce_cleanup(struct callout_cpu *cc, int direct) 243 { 244 245 cc_exec_curr(cc, direct) = NULL; 246 cc_exec_cancel(cc, direct) = false; 247 cc_exec_waiting(cc, direct) = false; 248 #ifdef SMP 249 cc_migration_cpu(cc, direct) = CPUBLOCK; 250 cc_migration_time(cc, direct) = 0; 251 cc_migration_prec(cc, direct) = 0; 252 cc_migration_func(cc, direct) = NULL; 253 cc_migration_arg(cc, direct) = NULL; 254 #endif 255 } 256 257 /* 258 * Checks if migration is requested by a specific callout cpu. 259 */ 260 static int 261 cc_cce_migrating(struct callout_cpu *cc, int direct) 262 { 263 264 #ifdef SMP 265 return (cc_migration_cpu(cc, direct) != CPUBLOCK); 266 #else 267 return (0); 268 #endif 269 } 270 271 /* 272 * Kernel low level callwheel initialization 273 * called on the BSP during kernel startup. 274 */ 275 static void 276 callout_callwheel_init(void *dummy) 277 { 278 struct callout_cpu *cc; 279 280 /* 281 * Calculate the size of the callout wheel and the preallocated 282 * timeout() structures. 283 * XXX: Clip callout to result of previous function of maxusers 284 * maximum 384. This is still huge, but acceptable. 285 */ 286 memset(CC_CPU(curcpu), 0, sizeof(cc_cpu)); 287 ncallout = imin(16 + maxproc + maxfiles, 18508); 288 TUNABLE_INT_FETCH("kern.ncallout", &ncallout); 289 290 /* 291 * Calculate callout wheel size, should be next power of two higher 292 * than 'ncallout'. 293 */ 294 callwheelsize = 1 << fls(ncallout); 295 callwheelmask = callwheelsize - 1; 296 297 /* 298 * Fetch whether we're pinning the swi's or not. 299 */ 300 TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi); 301 TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi); 302 303 /* 304 * Only BSP handles timeout(9) and receives a preallocation. 305 * 306 * XXX: Once all timeout(9) consumers are converted this can 307 * be removed. 308 */ 309 timeout_cpu = PCPU_GET(cpuid); 310 cc = CC_CPU(timeout_cpu); 311 cc->cc_callout = malloc(ncallout * sizeof(struct callout), 312 M_CALLOUT, M_WAITOK); 313 callout_cpu_init(cc, timeout_cpu); 314 } 315 SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); 316 317 /* 318 * Initialize the per-cpu callout structures. 319 */ 320 static void 321 callout_cpu_init(struct callout_cpu *cc, int cpu) 322 { 323 struct callout *c; 324 int i; 325 326 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); 327 SLIST_INIT(&cc->cc_callfree); 328 cc->cc_inited = 1; 329 cc->cc_callwheel = malloc_domainset(sizeof(struct callout_list) * 330 callwheelsize, M_CALLOUT, 331 DOMAINSET_PREF(pcpu_find(cpu)->pc_domain), M_WAITOK); 332 for (i = 0; i < callwheelsize; i++) 333 LIST_INIT(&cc->cc_callwheel[i]); 334 TAILQ_INIT(&cc->cc_expireq); 335 cc->cc_firstevent = SBT_MAX; 336 for (i = 0; i < 2; i++) 337 cc_cce_cleanup(cc, i); 338 snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name), 339 "callwheel cpu %d", cpu); 340 if (cc->cc_callout == NULL) /* Only BSP handles timeout(9) */ 341 return; 342 for (i = 0; i < ncallout; i++) { 343 c = &cc->cc_callout[i]; 344 callout_init(c, 0); 345 c->c_iflags = CALLOUT_LOCAL_ALLOC; 346 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 347 } 348 } 349 350 #ifdef SMP 351 /* 352 * Switches the cpu tied to a specific callout. 353 * The function expects a locked incoming callout cpu and returns with 354 * locked outcoming callout cpu. 355 */ 356 static struct callout_cpu * 357 callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu) 358 { 359 struct callout_cpu *new_cc; 360 361 MPASS(c != NULL && cc != NULL); 362 CC_LOCK_ASSERT(cc); 363 364 /* 365 * Avoid interrupts and preemption firing after the callout cpu 366 * is blocked in order to avoid deadlocks as the new thread 367 * may be willing to acquire the callout cpu lock. 368 */ 369 c->c_cpu = CPUBLOCK; 370 spinlock_enter(); 371 CC_UNLOCK(cc); 372 new_cc = CC_CPU(new_cpu); 373 CC_LOCK(new_cc); 374 spinlock_exit(); 375 c->c_cpu = new_cpu; 376 return (new_cc); 377 } 378 #endif 379 380 /* 381 * Start standard softclock thread. 382 */ 383 static void 384 start_softclock(void *dummy) 385 { 386 struct callout_cpu *cc; 387 char name[MAXCOMLEN]; 388 #ifdef SMP 389 int cpu; 390 struct intr_event *ie; 391 #endif 392 393 cc = CC_CPU(timeout_cpu); 394 snprintf(name, sizeof(name), "clock (%d)", timeout_cpu); 395 if (swi_add(&clk_intr_event, name, softclock, cc, SWI_CLOCK, 396 INTR_MPSAFE, &cc->cc_cookie)) 397 panic("died while creating standard software ithreads"); 398 if (pin_default_swi && 399 (intr_event_bind(clk_intr_event, timeout_cpu) != 0)) { 400 printf("%s: timeout clock couldn't be pinned to cpu %d\n", 401 __func__, 402 timeout_cpu); 403 } 404 405 #ifdef SMP 406 CPU_FOREACH(cpu) { 407 if (cpu == timeout_cpu) 408 continue; 409 cc = CC_CPU(cpu); 410 cc->cc_callout = NULL; /* Only BSP handles timeout(9). */ 411 callout_cpu_init(cc, cpu); 412 snprintf(name, sizeof(name), "clock (%d)", cpu); 413 ie = NULL; 414 if (swi_add(&ie, name, softclock, cc, SWI_CLOCK, 415 INTR_MPSAFE, &cc->cc_cookie)) 416 panic("died while creating standard software ithreads"); 417 if (pin_pcpu_swi && (intr_event_bind(ie, cpu) != 0)) { 418 printf("%s: per-cpu clock couldn't be pinned to " 419 "cpu %d\n", 420 __func__, 421 cpu); 422 } 423 } 424 #endif 425 } 426 SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); 427 428 #define CC_HASH_SHIFT 8 429 430 static inline u_int 431 callout_hash(sbintime_t sbt) 432 { 433 434 return (sbt >> (32 - CC_HASH_SHIFT)); 435 } 436 437 static inline u_int 438 callout_get_bucket(sbintime_t sbt) 439 { 440 441 return (callout_hash(sbt) & callwheelmask); 442 } 443 444 void 445 callout_process(sbintime_t now) 446 { 447 struct callout *tmp, *tmpn; 448 struct callout_cpu *cc; 449 struct callout_list *sc; 450 sbintime_t first, last, max, tmp_max; 451 uint32_t lookahead; 452 u_int firstb, lastb, nowb; 453 #ifdef CALLOUT_PROFILING 454 int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0; 455 #endif 456 457 cc = CC_SELF(); 458 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET); 459 460 /* Compute the buckets of the last scan and present times. */ 461 firstb = callout_hash(cc->cc_lastscan); 462 cc->cc_lastscan = now; 463 nowb = callout_hash(now); 464 465 /* Compute the last bucket and minimum time of the bucket after it. */ 466 if (nowb == firstb) 467 lookahead = (SBT_1S / 16); 468 else if (nowb - firstb == 1) 469 lookahead = (SBT_1S / 8); 470 else 471 lookahead = (SBT_1S / 2); 472 first = last = now; 473 first += (lookahead / 2); 474 last += lookahead; 475 last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); 476 lastb = callout_hash(last) - 1; 477 max = last; 478 479 /* 480 * Check if we wrapped around the entire wheel from the last scan. 481 * In case, we need to scan entirely the wheel for pending callouts. 482 */ 483 if (lastb - firstb >= callwheelsize) { 484 lastb = firstb + callwheelsize - 1; 485 if (nowb - firstb >= callwheelsize) 486 nowb = lastb; 487 } 488 489 /* Iterate callwheel from firstb to nowb and then up to lastb. */ 490 do { 491 sc = &cc->cc_callwheel[firstb & callwheelmask]; 492 tmp = LIST_FIRST(sc); 493 while (tmp != NULL) { 494 /* Run the callout if present time within allowed. */ 495 if (tmp->c_time <= now) { 496 /* 497 * Consumer told us the callout may be run 498 * directly from hardware interrupt context. 499 */ 500 if (tmp->c_iflags & CALLOUT_DIRECT) { 501 #ifdef CALLOUT_PROFILING 502 ++depth_dir; 503 #endif 504 cc_exec_next(cc) = 505 LIST_NEXT(tmp, c_links.le); 506 cc->cc_bucket = firstb & callwheelmask; 507 LIST_REMOVE(tmp, c_links.le); 508 softclock_call_cc(tmp, cc, 509 #ifdef CALLOUT_PROFILING 510 &mpcalls_dir, &lockcalls_dir, NULL, 511 #endif 512 1); 513 tmp = cc_exec_next(cc); 514 cc_exec_next(cc) = NULL; 515 } else { 516 tmpn = LIST_NEXT(tmp, c_links.le); 517 LIST_REMOVE(tmp, c_links.le); 518 TAILQ_INSERT_TAIL(&cc->cc_expireq, 519 tmp, c_links.tqe); 520 tmp->c_iflags |= CALLOUT_PROCESSED; 521 tmp = tmpn; 522 } 523 continue; 524 } 525 /* Skip events from distant future. */ 526 if (tmp->c_time >= max) 527 goto next; 528 /* 529 * Event minimal time is bigger than present maximal 530 * time, so it cannot be aggregated. 531 */ 532 if (tmp->c_time > last) { 533 lastb = nowb; 534 goto next; 535 } 536 /* Update first and last time, respecting this event. */ 537 if (tmp->c_time < first) 538 first = tmp->c_time; 539 tmp_max = tmp->c_time + tmp->c_precision; 540 if (tmp_max < last) 541 last = tmp_max; 542 next: 543 tmp = LIST_NEXT(tmp, c_links.le); 544 } 545 /* Proceed with the next bucket. */ 546 firstb++; 547 /* 548 * Stop if we looked after present time and found 549 * some event we can't execute at now. 550 * Stop if we looked far enough into the future. 551 */ 552 } while (((int)(firstb - lastb)) <= 0); 553 cc->cc_firstevent = last; 554 #ifndef NO_EVENTTIMERS 555 cpu_new_callout(curcpu, last, first); 556 #endif 557 #ifdef CALLOUT_PROFILING 558 avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8; 559 avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8; 560 avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8; 561 #endif 562 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 563 /* 564 * swi_sched acquires the thread lock, so we don't want to call it 565 * with cc_lock held; incorrect locking order. 566 */ 567 if (!TAILQ_EMPTY(&cc->cc_expireq)) 568 swi_sched(cc->cc_cookie, 0); 569 } 570 571 static struct callout_cpu * 572 callout_lock(struct callout *c) 573 { 574 struct callout_cpu *cc; 575 int cpu; 576 577 for (;;) { 578 cpu = c->c_cpu; 579 #ifdef SMP 580 if (cpu == CPUBLOCK) { 581 while (c->c_cpu == CPUBLOCK) 582 cpu_spinwait(); 583 continue; 584 } 585 #endif 586 cc = CC_CPU(cpu); 587 CC_LOCK(cc); 588 if (cpu == c->c_cpu) 589 break; 590 CC_UNLOCK(cc); 591 } 592 return (cc); 593 } 594 595 static void 596 callout_cc_add(struct callout *c, struct callout_cpu *cc, 597 sbintime_t sbt, sbintime_t precision, void (*func)(void *), 598 void *arg, int cpu, int flags) 599 { 600 int bucket; 601 602 CC_LOCK_ASSERT(cc); 603 if (sbt < cc->cc_lastscan) 604 sbt = cc->cc_lastscan; 605 c->c_arg = arg; 606 c->c_iflags |= CALLOUT_PENDING; 607 c->c_iflags &= ~CALLOUT_PROCESSED; 608 c->c_flags |= CALLOUT_ACTIVE; 609 if (flags & C_DIRECT_EXEC) 610 c->c_iflags |= CALLOUT_DIRECT; 611 c->c_func = func; 612 c->c_time = sbt; 613 c->c_precision = precision; 614 bucket = callout_get_bucket(c->c_time); 615 CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x", 616 c, (int)(c->c_precision >> 32), 617 (u_int)(c->c_precision & 0xffffffff)); 618 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); 619 if (cc->cc_bucket == bucket) 620 cc_exec_next(cc) = c; 621 #ifndef NO_EVENTTIMERS 622 /* 623 * Inform the eventtimers(4) subsystem there's a new callout 624 * that has been inserted, but only if really required. 625 */ 626 if (SBT_MAX - c->c_time < c->c_precision) 627 c->c_precision = SBT_MAX - c->c_time; 628 sbt = c->c_time + c->c_precision; 629 if (sbt < cc->cc_firstevent) { 630 cc->cc_firstevent = sbt; 631 cpu_new_callout(cpu, sbt, c->c_time); 632 } 633 #endif 634 } 635 636 static void 637 callout_cc_del(struct callout *c, struct callout_cpu *cc) 638 { 639 640 if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) == 0) 641 return; 642 c->c_func = NULL; 643 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 644 } 645 646 static void 647 softclock_call_cc(struct callout *c, struct callout_cpu *cc, 648 #ifdef CALLOUT_PROFILING 649 int *mpcalls, int *lockcalls, int *gcalls, 650 #endif 651 int direct) 652 { 653 struct rm_priotracker tracker; 654 void (*c_func)(void *); 655 void *c_arg; 656 struct lock_class *class; 657 struct lock_object *c_lock; 658 uintptr_t lock_status; 659 int c_iflags; 660 #ifdef SMP 661 struct callout_cpu *new_cc; 662 void (*new_func)(void *); 663 void *new_arg; 664 int flags, new_cpu; 665 sbintime_t new_prec, new_time; 666 #endif 667 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 668 sbintime_t sbt1, sbt2; 669 struct timespec ts2; 670 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 671 static timeout_t *lastfunc; 672 #endif 673 674 KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING, 675 ("softclock_call_cc: pend %p %x", c, c->c_iflags)); 676 KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE, 677 ("softclock_call_cc: act %p %x", c, c->c_flags)); 678 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; 679 lock_status = 0; 680 if (c->c_flags & CALLOUT_SHAREDLOCK) { 681 if (class == &lock_class_rm) 682 lock_status = (uintptr_t)&tracker; 683 else 684 lock_status = 1; 685 } 686 c_lock = c->c_lock; 687 c_func = c->c_func; 688 c_arg = c->c_arg; 689 c_iflags = c->c_iflags; 690 if (c->c_iflags & CALLOUT_LOCAL_ALLOC) 691 c->c_iflags = CALLOUT_LOCAL_ALLOC; 692 else 693 c->c_iflags &= ~CALLOUT_PENDING; 694 695 cc_exec_curr(cc, direct) = c; 696 cc_exec_last_func(cc, direct) = c_func; 697 cc_exec_last_arg(cc, direct) = c_arg; 698 cc_exec_cancel(cc, direct) = false; 699 cc_exec_drain(cc, direct) = NULL; 700 CC_UNLOCK(cc); 701 if (c_lock != NULL) { 702 class->lc_lock(c_lock, lock_status); 703 /* 704 * The callout may have been cancelled 705 * while we switched locks. 706 */ 707 if (cc_exec_cancel(cc, direct)) { 708 class->lc_unlock(c_lock); 709 goto skip; 710 } 711 /* The callout cannot be stopped now. */ 712 cc_exec_cancel(cc, direct) = true; 713 if (c_lock == &Giant.lock_object) { 714 #ifdef CALLOUT_PROFILING 715 (*gcalls)++; 716 #endif 717 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", 718 c, c_func, c_arg); 719 } else { 720 #ifdef CALLOUT_PROFILING 721 (*lockcalls)++; 722 #endif 723 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", 724 c, c_func, c_arg); 725 } 726 } else { 727 #ifdef CALLOUT_PROFILING 728 (*mpcalls)++; 729 #endif 730 CTR3(KTR_CALLOUT, "callout %p func %p arg %p", 731 c, c_func, c_arg); 732 } 733 KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running", 734 "func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct); 735 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 736 sbt1 = sbinuptime(); 737 #endif 738 THREAD_NO_SLEEPING(); 739 SDT_PROBE1(callout_execute, , , callout__start, c); 740 c_func(c_arg); 741 SDT_PROBE1(callout_execute, , , callout__end, c); 742 THREAD_SLEEPING_OK(); 743 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 744 sbt2 = sbinuptime(); 745 sbt2 -= sbt1; 746 if (sbt2 > maxdt) { 747 if (lastfunc != c_func || sbt2 > maxdt * 2) { 748 ts2 = sbttots(sbt2); 749 printf( 750 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 751 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); 752 } 753 maxdt = sbt2; 754 lastfunc = c_func; 755 } 756 #endif 757 KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle"); 758 CTR1(KTR_CALLOUT, "callout %p finished", c); 759 if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0) 760 class->lc_unlock(c_lock); 761 skip: 762 CC_LOCK(cc); 763 KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr")); 764 cc_exec_curr(cc, direct) = NULL; 765 if (cc_exec_drain(cc, direct)) { 766 void (*drain)(void *); 767 768 drain = cc_exec_drain(cc, direct); 769 cc_exec_drain(cc, direct) = NULL; 770 CC_UNLOCK(cc); 771 drain(c_arg); 772 CC_LOCK(cc); 773 } 774 if (cc_exec_waiting(cc, direct)) { 775 /* 776 * There is someone waiting for the 777 * callout to complete. 778 * If the callout was scheduled for 779 * migration just cancel it. 780 */ 781 if (cc_cce_migrating(cc, direct)) { 782 cc_cce_cleanup(cc, direct); 783 784 /* 785 * It should be assert here that the callout is not 786 * destroyed but that is not easy. 787 */ 788 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 789 } 790 cc_exec_waiting(cc, direct) = false; 791 CC_UNLOCK(cc); 792 wakeup(&cc_exec_waiting(cc, direct)); 793 CC_LOCK(cc); 794 } else if (cc_cce_migrating(cc, direct)) { 795 KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0, 796 ("Migrating legacy callout %p", c)); 797 #ifdef SMP 798 /* 799 * If the callout was scheduled for 800 * migration just perform it now. 801 */ 802 new_cpu = cc_migration_cpu(cc, direct); 803 new_time = cc_migration_time(cc, direct); 804 new_prec = cc_migration_prec(cc, direct); 805 new_func = cc_migration_func(cc, direct); 806 new_arg = cc_migration_arg(cc, direct); 807 cc_cce_cleanup(cc, direct); 808 809 /* 810 * It should be assert here that the callout is not destroyed 811 * but that is not easy. 812 * 813 * As first thing, handle deferred callout stops. 814 */ 815 if (!callout_migrating(c)) { 816 CTR3(KTR_CALLOUT, 817 "deferred cancelled %p func %p arg %p", 818 c, new_func, new_arg); 819 callout_cc_del(c, cc); 820 return; 821 } 822 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 823 824 new_cc = callout_cpu_switch(c, cc, new_cpu); 825 flags = (direct) ? C_DIRECT_EXEC : 0; 826 callout_cc_add(c, new_cc, new_time, new_prec, new_func, 827 new_arg, new_cpu, flags); 828 CC_UNLOCK(new_cc); 829 CC_LOCK(cc); 830 #else 831 panic("migration should not happen"); 832 #endif 833 } 834 /* 835 * If the current callout is locally allocated (from 836 * timeout(9)) then put it on the freelist. 837 * 838 * Note: we need to check the cached copy of c_iflags because 839 * if it was not local, then it's not safe to deref the 840 * callout pointer. 841 */ 842 KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0 || 843 c->c_iflags == CALLOUT_LOCAL_ALLOC, 844 ("corrupted callout")); 845 if (c_iflags & CALLOUT_LOCAL_ALLOC) 846 callout_cc_del(c, cc); 847 } 848 849 /* 850 * The callout mechanism is based on the work of Adam M. Costello and 851 * George Varghese, published in a technical report entitled "Redesigning 852 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 853 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 854 * used in this implementation was published by G. Varghese and T. Lauck in 855 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 856 * the Efficient Implementation of a Timer Facility" in the Proceedings of 857 * the 11th ACM Annual Symposium on Operating Systems Principles, 858 * Austin, Texas Nov 1987. 859 */ 860 861 /* 862 * Software (low priority) clock interrupt. 863 * Run periodic events from timeout queue. 864 */ 865 void 866 softclock(void *arg) 867 { 868 struct callout_cpu *cc; 869 struct callout *c; 870 #ifdef CALLOUT_PROFILING 871 int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0; 872 #endif 873 874 cc = (struct callout_cpu *)arg; 875 CC_LOCK(cc); 876 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { 877 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 878 softclock_call_cc(c, cc, 879 #ifdef CALLOUT_PROFILING 880 &mpcalls, &lockcalls, &gcalls, 881 #endif 882 0); 883 #ifdef CALLOUT_PROFILING 884 ++depth; 885 #endif 886 } 887 #ifdef CALLOUT_PROFILING 888 avg_depth += (depth * 1000 - avg_depth) >> 8; 889 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 890 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 891 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 892 #endif 893 CC_UNLOCK(cc); 894 } 895 896 /* 897 * timeout -- 898 * Execute a function after a specified length of time. 899 * 900 * untimeout -- 901 * Cancel previous timeout function call. 902 * 903 * callout_handle_init -- 904 * Initialize a handle so that using it with untimeout is benign. 905 * 906 * See AT&T BCI Driver Reference Manual for specification. This 907 * implementation differs from that one in that although an 908 * identification value is returned from timeout, the original 909 * arguments to timeout as well as the identifier are used to 910 * identify entries for untimeout. 911 */ 912 struct callout_handle 913 timeout(timeout_t *ftn, void *arg, int to_ticks) 914 { 915 struct callout_cpu *cc; 916 struct callout *new; 917 struct callout_handle handle; 918 919 cc = CC_CPU(timeout_cpu); 920 CC_LOCK(cc); 921 /* Fill in the next free callout structure. */ 922 new = SLIST_FIRST(&cc->cc_callfree); 923 if (new == NULL) 924 /* XXX Attempt to malloc first */ 925 panic("timeout table full"); 926 SLIST_REMOVE_HEAD(&cc->cc_callfree, c_links.sle); 927 callout_reset(new, to_ticks, ftn, arg); 928 handle.callout = new; 929 CC_UNLOCK(cc); 930 931 return (handle); 932 } 933 934 void 935 untimeout(timeout_t *ftn, void *arg, struct callout_handle handle) 936 { 937 struct callout_cpu *cc; 938 939 /* 940 * Check for a handle that was initialized 941 * by callout_handle_init, but never used 942 * for a real timeout. 943 */ 944 if (handle.callout == NULL) 945 return; 946 947 cc = callout_lock(handle.callout); 948 if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) 949 callout_stop(handle.callout); 950 CC_UNLOCK(cc); 951 } 952 953 void 954 callout_handle_init(struct callout_handle *handle) 955 { 956 handle->callout = NULL; 957 } 958 959 void 960 callout_when(sbintime_t sbt, sbintime_t precision, int flags, 961 sbintime_t *res, sbintime_t *prec_res) 962 { 963 sbintime_t to_sbt, to_pr; 964 965 if ((flags & (C_ABSOLUTE | C_PRECALC)) != 0) { 966 *res = sbt; 967 *prec_res = precision; 968 return; 969 } 970 if ((flags & C_HARDCLOCK) != 0 && sbt < tick_sbt) 971 sbt = tick_sbt; 972 if ((flags & C_HARDCLOCK) != 0 || 973 #ifdef NO_EVENTTIMERS 974 sbt >= sbt_timethreshold) { 975 to_sbt = getsbinuptime(); 976 977 /* Add safety belt for the case of hz > 1000. */ 978 to_sbt += tc_tick_sbt - tick_sbt; 979 #else 980 sbt >= sbt_tickthreshold) { 981 /* 982 * Obtain the time of the last hardclock() call on 983 * this CPU directly from the kern_clocksource.c. 984 * This value is per-CPU, but it is equal for all 985 * active ones. 986 */ 987 #ifdef __LP64__ 988 to_sbt = DPCPU_GET(hardclocktime); 989 #else 990 spinlock_enter(); 991 to_sbt = DPCPU_GET(hardclocktime); 992 spinlock_exit(); 993 #endif 994 #endif 995 if (cold && to_sbt == 0) 996 to_sbt = sbinuptime(); 997 if ((flags & C_HARDCLOCK) == 0) 998 to_sbt += tick_sbt; 999 } else 1000 to_sbt = sbinuptime(); 1001 if (SBT_MAX - to_sbt < sbt) 1002 to_sbt = SBT_MAX; 1003 else 1004 to_sbt += sbt; 1005 *res = to_sbt; 1006 to_pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : 1007 sbt >> C_PRELGET(flags)); 1008 *prec_res = to_pr > precision ? to_pr : precision; 1009 } 1010 1011 /* 1012 * New interface; clients allocate their own callout structures. 1013 * 1014 * callout_reset() - establish or change a timeout 1015 * callout_stop() - disestablish a timeout 1016 * callout_init() - initialize a callout structure so that it can 1017 * safely be passed to callout_reset() and callout_stop() 1018 * 1019 * <sys/callout.h> defines three convenience macros: 1020 * 1021 * callout_active() - returns truth if callout has not been stopped, 1022 * drained, or deactivated since the last time the callout was 1023 * reset. 1024 * callout_pending() - returns truth if callout is still waiting for timeout 1025 * callout_deactivate() - marks the callout as having been serviced 1026 */ 1027 int 1028 callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t prec, 1029 void (*ftn)(void *), void *arg, int cpu, int flags) 1030 { 1031 sbintime_t to_sbt, precision; 1032 struct callout_cpu *cc; 1033 int cancelled, direct; 1034 int ignore_cpu=0; 1035 1036 cancelled = 0; 1037 if (cpu == -1) { 1038 ignore_cpu = 1; 1039 } else if ((cpu >= MAXCPU) || 1040 ((CC_CPU(cpu))->cc_inited == 0)) { 1041 /* Invalid CPU spec */ 1042 panic("Invalid CPU in callout %d", cpu); 1043 } 1044 callout_when(sbt, prec, flags, &to_sbt, &precision); 1045 1046 /* 1047 * This flag used to be added by callout_cc_add, but the 1048 * first time you call this we could end up with the 1049 * wrong direct flag if we don't do it before we add. 1050 */ 1051 if (flags & C_DIRECT_EXEC) { 1052 direct = 1; 1053 } else { 1054 direct = 0; 1055 } 1056 KASSERT(!direct || c->c_lock == NULL, 1057 ("%s: direct callout %p has lock", __func__, c)); 1058 cc = callout_lock(c); 1059 /* 1060 * Don't allow migration of pre-allocated callouts lest they 1061 * become unbalanced or handle the case where the user does 1062 * not care. 1063 */ 1064 if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) || 1065 ignore_cpu) { 1066 cpu = c->c_cpu; 1067 } 1068 1069 if (cc_exec_curr(cc, direct) == c) { 1070 /* 1071 * We're being asked to reschedule a callout which is 1072 * currently in progress. If there is a lock then we 1073 * can cancel the callout if it has not really started. 1074 */ 1075 if (c->c_lock != NULL && !cc_exec_cancel(cc, direct)) 1076 cancelled = cc_exec_cancel(cc, direct) = true; 1077 if (cc_exec_waiting(cc, direct) || cc_exec_drain(cc, direct)) { 1078 /* 1079 * Someone has called callout_drain to kill this 1080 * callout. Don't reschedule. 1081 */ 1082 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 1083 cancelled ? "cancelled" : "failed to cancel", 1084 c, c->c_func, c->c_arg); 1085 CC_UNLOCK(cc); 1086 return (cancelled); 1087 } 1088 #ifdef SMP 1089 if (callout_migrating(c)) { 1090 /* 1091 * This only occurs when a second callout_reset_sbt_on 1092 * is made after a previous one moved it into 1093 * deferred migration (below). Note we do *not* change 1094 * the prev_cpu even though the previous target may 1095 * be different. 1096 */ 1097 cc_migration_cpu(cc, direct) = cpu; 1098 cc_migration_time(cc, direct) = to_sbt; 1099 cc_migration_prec(cc, direct) = precision; 1100 cc_migration_func(cc, direct) = ftn; 1101 cc_migration_arg(cc, direct) = arg; 1102 cancelled = 1; 1103 CC_UNLOCK(cc); 1104 return (cancelled); 1105 } 1106 #endif 1107 } 1108 if (c->c_iflags & CALLOUT_PENDING) { 1109 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1110 if (cc_exec_next(cc) == c) 1111 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1112 LIST_REMOVE(c, c_links.le); 1113 } else { 1114 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1115 } 1116 cancelled = 1; 1117 c->c_iflags &= ~ CALLOUT_PENDING; 1118 c->c_flags &= ~ CALLOUT_ACTIVE; 1119 } 1120 1121 #ifdef SMP 1122 /* 1123 * If the callout must migrate try to perform it immediately. 1124 * If the callout is currently running, just defer the migration 1125 * to a more appropriate moment. 1126 */ 1127 if (c->c_cpu != cpu) { 1128 if (cc_exec_curr(cc, direct) == c) { 1129 /* 1130 * Pending will have been removed since we are 1131 * actually executing the callout on another 1132 * CPU. That callout should be waiting on the 1133 * lock the caller holds. If we set both 1134 * active/and/pending after we return and the 1135 * lock on the executing callout proceeds, it 1136 * will then see pending is true and return. 1137 * At the return from the actual callout execution 1138 * the migration will occur in softclock_call_cc 1139 * and this new callout will be placed on the 1140 * new CPU via a call to callout_cpu_switch() which 1141 * will get the lock on the right CPU followed 1142 * by a call callout_cc_add() which will add it there. 1143 * (see above in softclock_call_cc()). 1144 */ 1145 cc_migration_cpu(cc, direct) = cpu; 1146 cc_migration_time(cc, direct) = to_sbt; 1147 cc_migration_prec(cc, direct) = precision; 1148 cc_migration_func(cc, direct) = ftn; 1149 cc_migration_arg(cc, direct) = arg; 1150 c->c_iflags |= (CALLOUT_DFRMIGRATION | CALLOUT_PENDING); 1151 c->c_flags |= CALLOUT_ACTIVE; 1152 CTR6(KTR_CALLOUT, 1153 "migration of %p func %p arg %p in %d.%08x to %u deferred", 1154 c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1155 (u_int)(to_sbt & 0xffffffff), cpu); 1156 CC_UNLOCK(cc); 1157 return (cancelled); 1158 } 1159 cc = callout_cpu_switch(c, cc, cpu); 1160 } 1161 #endif 1162 1163 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags); 1164 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", 1165 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1166 (u_int)(to_sbt & 0xffffffff)); 1167 CC_UNLOCK(cc); 1168 1169 return (cancelled); 1170 } 1171 1172 /* 1173 * Common idioms that can be optimized in the future. 1174 */ 1175 int 1176 callout_schedule_on(struct callout *c, int to_ticks, int cpu) 1177 { 1178 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 1179 } 1180 1181 int 1182 callout_schedule(struct callout *c, int to_ticks) 1183 { 1184 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 1185 } 1186 1187 int 1188 _callout_stop_safe(struct callout *c, int flags, void (*drain)(void *)) 1189 { 1190 struct callout_cpu *cc, *old_cc; 1191 struct lock_class *class; 1192 int direct, sq_locked, use_lock; 1193 int cancelled, not_on_a_list; 1194 1195 if ((flags & CS_DRAIN) != 0) 1196 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock, 1197 "calling %s", __func__); 1198 1199 /* 1200 * Some old subsystems don't hold Giant while running a callout_stop(), 1201 * so just discard this check for the moment. 1202 */ 1203 if ((flags & CS_DRAIN) == 0 && c->c_lock != NULL) { 1204 if (c->c_lock == &Giant.lock_object) 1205 use_lock = mtx_owned(&Giant); 1206 else { 1207 use_lock = 1; 1208 class = LOCK_CLASS(c->c_lock); 1209 class->lc_assert(c->c_lock, LA_XLOCKED); 1210 } 1211 } else 1212 use_lock = 0; 1213 if (c->c_iflags & CALLOUT_DIRECT) { 1214 direct = 1; 1215 } else { 1216 direct = 0; 1217 } 1218 sq_locked = 0; 1219 old_cc = NULL; 1220 again: 1221 cc = callout_lock(c); 1222 1223 if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) == 1224 (CALLOUT_DFRMIGRATION | CALLOUT_PENDING) && 1225 ((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) { 1226 /* 1227 * Special case where this slipped in while we 1228 * were migrating *as* the callout is about to 1229 * execute. The caller probably holds the lock 1230 * the callout wants. 1231 * 1232 * Get rid of the migration first. Then set 1233 * the flag that tells this code *not* to 1234 * try to remove it from any lists (its not 1235 * on one yet). When the callout wheel runs, 1236 * it will ignore this callout. 1237 */ 1238 c->c_iflags &= ~CALLOUT_PENDING; 1239 c->c_flags &= ~CALLOUT_ACTIVE; 1240 not_on_a_list = 1; 1241 } else { 1242 not_on_a_list = 0; 1243 } 1244 1245 /* 1246 * If the callout was migrating while the callout cpu lock was 1247 * dropped, just drop the sleepqueue lock and check the states 1248 * again. 1249 */ 1250 if (sq_locked != 0 && cc != old_cc) { 1251 #ifdef SMP 1252 CC_UNLOCK(cc); 1253 sleepq_release(&cc_exec_waiting(old_cc, direct)); 1254 sq_locked = 0; 1255 old_cc = NULL; 1256 goto again; 1257 #else 1258 panic("migration should not happen"); 1259 #endif 1260 } 1261 1262 /* 1263 * If the callout is running, try to stop it or drain it. 1264 */ 1265 if (cc_exec_curr(cc, direct) == c) { 1266 /* 1267 * Succeed we to stop it or not, we must clear the 1268 * active flag - this is what API users expect. If we're 1269 * draining and the callout is currently executing, first wait 1270 * until it finishes. 1271 */ 1272 if ((flags & CS_DRAIN) == 0) 1273 c->c_flags &= ~CALLOUT_ACTIVE; 1274 1275 if ((flags & CS_DRAIN) != 0) { 1276 /* 1277 * The current callout is running (or just 1278 * about to run) and blocking is allowed, so 1279 * just wait for the current invocation to 1280 * finish. 1281 */ 1282 while (cc_exec_curr(cc, direct) == c) { 1283 /* 1284 * Use direct calls to sleepqueue interface 1285 * instead of cv/msleep in order to avoid 1286 * a LOR between cc_lock and sleepqueue 1287 * chain spinlocks. This piece of code 1288 * emulates a msleep_spin() call actually. 1289 * 1290 * If we already have the sleepqueue chain 1291 * locked, then we can safely block. If we 1292 * don't already have it locked, however, 1293 * we have to drop the cc_lock to lock 1294 * it. This opens several races, so we 1295 * restart at the beginning once we have 1296 * both locks. If nothing has changed, then 1297 * we will end up back here with sq_locked 1298 * set. 1299 */ 1300 if (!sq_locked) { 1301 CC_UNLOCK(cc); 1302 sleepq_lock( 1303 &cc_exec_waiting(cc, direct)); 1304 sq_locked = 1; 1305 old_cc = cc; 1306 goto again; 1307 } 1308 1309 /* 1310 * Migration could be cancelled here, but 1311 * as long as it is still not sure when it 1312 * will be packed up, just let softclock() 1313 * take care of it. 1314 */ 1315 cc_exec_waiting(cc, direct) = true; 1316 DROP_GIANT(); 1317 CC_UNLOCK(cc); 1318 sleepq_add( 1319 &cc_exec_waiting(cc, direct), 1320 &cc->cc_lock.lock_object, "codrain", 1321 SLEEPQ_SLEEP, 0); 1322 sleepq_wait( 1323 &cc_exec_waiting(cc, direct), 1324 0); 1325 sq_locked = 0; 1326 old_cc = NULL; 1327 1328 /* Reacquire locks previously released. */ 1329 PICKUP_GIANT(); 1330 CC_LOCK(cc); 1331 } 1332 c->c_flags &= ~CALLOUT_ACTIVE; 1333 } else if (use_lock && 1334 !cc_exec_cancel(cc, direct) && (drain == NULL)) { 1335 1336 /* 1337 * The current callout is waiting for its 1338 * lock which we hold. Cancel the callout 1339 * and return. After our caller drops the 1340 * lock, the callout will be skipped in 1341 * softclock(). This *only* works with a 1342 * callout_stop() *not* callout_drain() or 1343 * callout_async_drain(). 1344 */ 1345 cc_exec_cancel(cc, direct) = true; 1346 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1347 c, c->c_func, c->c_arg); 1348 KASSERT(!cc_cce_migrating(cc, direct), 1349 ("callout wrongly scheduled for migration")); 1350 if (callout_migrating(c)) { 1351 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1352 #ifdef SMP 1353 cc_migration_cpu(cc, direct) = CPUBLOCK; 1354 cc_migration_time(cc, direct) = 0; 1355 cc_migration_prec(cc, direct) = 0; 1356 cc_migration_func(cc, direct) = NULL; 1357 cc_migration_arg(cc, direct) = NULL; 1358 #endif 1359 } 1360 CC_UNLOCK(cc); 1361 KASSERT(!sq_locked, ("sleepqueue chain locked")); 1362 return (1); 1363 } else if (callout_migrating(c)) { 1364 /* 1365 * The callout is currently being serviced 1366 * and the "next" callout is scheduled at 1367 * its completion with a migration. We remove 1368 * the migration flag so it *won't* get rescheduled, 1369 * but we can't stop the one thats running so 1370 * we return 0. 1371 */ 1372 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 1373 #ifdef SMP 1374 /* 1375 * We can't call cc_cce_cleanup here since 1376 * if we do it will remove .ce_curr and 1377 * its still running. This will prevent a 1378 * reschedule of the callout when the 1379 * execution completes. 1380 */ 1381 cc_migration_cpu(cc, direct) = CPUBLOCK; 1382 cc_migration_time(cc, direct) = 0; 1383 cc_migration_prec(cc, direct) = 0; 1384 cc_migration_func(cc, direct) = NULL; 1385 cc_migration_arg(cc, direct) = NULL; 1386 #endif 1387 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 1388 c, c->c_func, c->c_arg); 1389 if (drain) { 1390 cc_exec_drain(cc, direct) = drain; 1391 } 1392 CC_UNLOCK(cc); 1393 return ((flags & CS_EXECUTING) != 0); 1394 } 1395 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1396 c, c->c_func, c->c_arg); 1397 if (drain) { 1398 cc_exec_drain(cc, direct) = drain; 1399 } 1400 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 1401 cancelled = ((flags & CS_EXECUTING) != 0); 1402 } else 1403 cancelled = 1; 1404 1405 if (sq_locked) 1406 sleepq_release(&cc_exec_waiting(cc, direct)); 1407 1408 if ((c->c_iflags & CALLOUT_PENDING) == 0) { 1409 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1410 c, c->c_func, c->c_arg); 1411 /* 1412 * For not scheduled and not executing callout return 1413 * negative value. 1414 */ 1415 if (cc_exec_curr(cc, direct) != c) 1416 cancelled = -1; 1417 CC_UNLOCK(cc); 1418 return (cancelled); 1419 } 1420 1421 c->c_iflags &= ~CALLOUT_PENDING; 1422 c->c_flags &= ~CALLOUT_ACTIVE; 1423 1424 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1425 c, c->c_func, c->c_arg); 1426 if (not_on_a_list == 0) { 1427 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 1428 if (cc_exec_next(cc) == c) 1429 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1430 LIST_REMOVE(c, c_links.le); 1431 } else { 1432 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1433 } 1434 } 1435 callout_cc_del(c, cc); 1436 CC_UNLOCK(cc); 1437 return (cancelled); 1438 } 1439 1440 void 1441 callout_init(struct callout *c, int mpsafe) 1442 { 1443 bzero(c, sizeof *c); 1444 if (mpsafe) { 1445 c->c_lock = NULL; 1446 c->c_iflags = CALLOUT_RETURNUNLOCKED; 1447 } else { 1448 c->c_lock = &Giant.lock_object; 1449 c->c_iflags = 0; 1450 } 1451 c->c_cpu = timeout_cpu; 1452 } 1453 1454 void 1455 _callout_init_lock(struct callout *c, struct lock_object *lock, int flags) 1456 { 1457 bzero(c, sizeof *c); 1458 c->c_lock = lock; 1459 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1460 ("callout_init_lock: bad flags %d", flags)); 1461 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1462 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1463 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & 1464 (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class", 1465 __func__)); 1466 c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1467 c->c_cpu = timeout_cpu; 1468 } 1469 1470 #ifdef APM_FIXUP_CALLTODO 1471 /* 1472 * Adjust the kernel calltodo timeout list. This routine is used after 1473 * an APM resume to recalculate the calltodo timer list values with the 1474 * number of hz's we have been sleeping. The next hardclock() will detect 1475 * that there are fired timers and run softclock() to execute them. 1476 * 1477 * Please note, I have not done an exhaustive analysis of what code this 1478 * might break. I am motivated to have my select()'s and alarm()'s that 1479 * have expired during suspend firing upon resume so that the applications 1480 * which set the timer can do the maintanence the timer was for as close 1481 * as possible to the originally intended time. Testing this code for a 1482 * week showed that resuming from a suspend resulted in 22 to 25 timers 1483 * firing, which seemed independent on whether the suspend was 2 hours or 1484 * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu> 1485 */ 1486 void 1487 adjust_timeout_calltodo(struct timeval *time_change) 1488 { 1489 struct callout *p; 1490 unsigned long delta_ticks; 1491 1492 /* 1493 * How many ticks were we asleep? 1494 * (stolen from tvtohz()). 1495 */ 1496 1497 /* Don't do anything */ 1498 if (time_change->tv_sec < 0) 1499 return; 1500 else if (time_change->tv_sec <= LONG_MAX / 1000000) 1501 delta_ticks = howmany(time_change->tv_sec * 1000000 + 1502 time_change->tv_usec, tick) + 1; 1503 else if (time_change->tv_sec <= LONG_MAX / hz) 1504 delta_ticks = time_change->tv_sec * hz + 1505 howmany(time_change->tv_usec, tick) + 1; 1506 else 1507 delta_ticks = LONG_MAX; 1508 1509 if (delta_ticks > INT_MAX) 1510 delta_ticks = INT_MAX; 1511 1512 /* 1513 * Now rip through the timer calltodo list looking for timers 1514 * to expire. 1515 */ 1516 1517 /* don't collide with softclock() */ 1518 CC_LOCK(cc); 1519 for (p = calltodo.c_next; p != NULL; p = p->c_next) { 1520 p->c_time -= delta_ticks; 1521 1522 /* Break if the timer had more time on it than delta_ticks */ 1523 if (p->c_time > 0) 1524 break; 1525 1526 /* take back the ticks the timer didn't use (p->c_time <= 0) */ 1527 delta_ticks = -p->c_time; 1528 } 1529 CC_UNLOCK(cc); 1530 1531 return; 1532 } 1533 #endif /* APM_FIXUP_CALLTODO */ 1534 1535 static int 1536 flssbt(sbintime_t sbt) 1537 { 1538 1539 sbt += (uint64_t)sbt >> 1; 1540 if (sizeof(long) >= sizeof(sbintime_t)) 1541 return (flsl(sbt)); 1542 if (sbt >= SBT_1S) 1543 return (flsl(((uint64_t)sbt) >> 32) + 32); 1544 return (flsl(sbt)); 1545 } 1546 1547 /* 1548 * Dump immediate statistic snapshot of the scheduled callouts. 1549 */ 1550 static int 1551 sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1552 { 1553 struct callout *tmp; 1554 struct callout_cpu *cc; 1555 struct callout_list *sc; 1556 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; 1557 int ct[64], cpr[64], ccpbk[32]; 1558 int error, val, i, count, tcum, pcum, maxc, c, medc; 1559 #ifdef SMP 1560 int cpu; 1561 #endif 1562 1563 val = 0; 1564 error = sysctl_handle_int(oidp, &val, 0, req); 1565 if (error != 0 || req->newptr == NULL) 1566 return (error); 1567 count = maxc = 0; 1568 st = spr = maxt = maxpr = 0; 1569 bzero(ccpbk, sizeof(ccpbk)); 1570 bzero(ct, sizeof(ct)); 1571 bzero(cpr, sizeof(cpr)); 1572 now = sbinuptime(); 1573 #ifdef SMP 1574 CPU_FOREACH(cpu) { 1575 cc = CC_CPU(cpu); 1576 #else 1577 cc = CC_CPU(timeout_cpu); 1578 #endif 1579 CC_LOCK(cc); 1580 for (i = 0; i < callwheelsize; i++) { 1581 sc = &cc->cc_callwheel[i]; 1582 c = 0; 1583 LIST_FOREACH(tmp, sc, c_links.le) { 1584 c++; 1585 t = tmp->c_time - now; 1586 if (t < 0) 1587 t = 0; 1588 st += t / SBT_1US; 1589 spr += tmp->c_precision / SBT_1US; 1590 if (t > maxt) 1591 maxt = t; 1592 if (tmp->c_precision > maxpr) 1593 maxpr = tmp->c_precision; 1594 ct[flssbt(t)]++; 1595 cpr[flssbt(tmp->c_precision)]++; 1596 } 1597 if (c > maxc) 1598 maxc = c; 1599 ccpbk[fls(c + c / 2)]++; 1600 count += c; 1601 } 1602 CC_UNLOCK(cc); 1603 #ifdef SMP 1604 } 1605 #endif 1606 1607 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1608 tcum += ct[i]; 1609 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1610 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) 1611 pcum += cpr[i]; 1612 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1613 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1614 c += ccpbk[i]; 1615 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1616 1617 printf("Scheduled callouts statistic snapshot:\n"); 1618 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1619 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1620 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1621 medc, 1622 count / callwheelsize / mp_ncpus, 1623 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1624 maxc); 1625 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1626 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1627 (st / count) / 1000000, (st / count) % 1000000, 1628 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); 1629 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1630 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, 1631 (spr / count) / 1000000, (spr / count) % 1000000, 1632 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); 1633 printf(" Distribution: \tbuckets\t time\t tcum\t" 1634 " prec\t pcum\n"); 1635 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1636 if (ct[i] == 0 && cpr[i] == 0) 1637 continue; 1638 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1639 tcum += ct[i]; 1640 pcum += cpr[i]; 1641 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", 1642 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1643 i - 1 - (32 - CC_HASH_SHIFT), 1644 ct[i], tcum, cpr[i], pcum); 1645 } 1646 return (error); 1647 } 1648 SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1649 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1650 0, 0, sysctl_kern_callout_stat, "I", 1651 "Dump immediate statistic snapshot of the scheduled callouts"); 1652 1653 #ifdef DDB 1654 static void 1655 _show_callout(struct callout *c) 1656 { 1657 1658 db_printf("callout %p\n", c); 1659 #define C_DB_PRINTF(f, e) db_printf(" %s = " f "\n", #e, c->e); 1660 db_printf(" &c_links = %p\n", &(c->c_links)); 1661 C_DB_PRINTF("%" PRId64, c_time); 1662 C_DB_PRINTF("%" PRId64, c_precision); 1663 C_DB_PRINTF("%p", c_arg); 1664 C_DB_PRINTF("%p", c_func); 1665 C_DB_PRINTF("%p", c_lock); 1666 C_DB_PRINTF("%#x", c_flags); 1667 C_DB_PRINTF("%#x", c_iflags); 1668 C_DB_PRINTF("%d", c_cpu); 1669 #undef C_DB_PRINTF 1670 } 1671 1672 DB_SHOW_COMMAND(callout, db_show_callout) 1673 { 1674 1675 if (!have_addr) { 1676 db_printf("usage: show callout <struct callout *>\n"); 1677 return; 1678 } 1679 1680 _show_callout((struct callout *)addr); 1681 } 1682 1683 static void 1684 _show_last_callout(int cpu, int direct, const char *dirstr) 1685 { 1686 struct callout_cpu *cc; 1687 void *func, *arg; 1688 1689 cc = CC_CPU(cpu); 1690 func = cc_exec_last_func(cc, direct); 1691 arg = cc_exec_last_arg(cc, direct); 1692 db_printf("cpu %d last%s callout function: %p ", cpu, dirstr, func); 1693 db_printsym((db_expr_t)func, DB_STGY_ANY); 1694 db_printf("\ncpu %d last%s callout argument: %p\n", cpu, dirstr, arg); 1695 } 1696 1697 DB_SHOW_COMMAND(callout_last, db_show_callout_last) 1698 { 1699 int cpu, last; 1700 1701 if (have_addr) { 1702 if (addr < 0 || addr > mp_maxid || CPU_ABSENT(addr)) { 1703 db_printf("no such cpu: %d\n", (int)addr); 1704 return; 1705 } 1706 cpu = last = addr; 1707 } else { 1708 cpu = 0; 1709 last = mp_maxid; 1710 } 1711 1712 while (cpu <= last) { 1713 if (!CPU_ABSENT(cpu)) { 1714 _show_last_callout(cpu, 0, ""); 1715 _show_last_callout(cpu, 1, " direct"); 1716 } 1717 cpu++; 1718 } 1719 } 1720 #endif /* DDB */ 1721