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