1 /*- 2 * Copyright (c) 1982, 1986, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include "opt_callout_profiling.h" 41 #include "opt_kdtrace.h" 42 #if defined(__arm__) 43 #include "opt_timer.h" 44 #endif 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/bus.h> 49 #include <sys/callout.h> 50 #include <sys/file.h> 51 #include <sys/interrupt.h> 52 #include <sys/kernel.h> 53 #include <sys/ktr.h> 54 #include <sys/lock.h> 55 #include <sys/malloc.h> 56 #include <sys/mutex.h> 57 #include <sys/proc.h> 58 #include <sys/sdt.h> 59 #include <sys/sleepqueue.h> 60 #include <sys/sysctl.h> 61 #include <sys/smp.h> 62 63 #ifdef SMP 64 #include <machine/cpu.h> 65 #endif 66 67 #ifndef NO_EVENTTIMERS 68 DPCPU_DECLARE(sbintime_t, hardclocktime); 69 #endif 70 71 SDT_PROVIDER_DEFINE(callout_execute); 72 SDT_PROBE_DEFINE(callout_execute, kernel, , callout_start, callout-start); 73 SDT_PROBE_ARGTYPE(callout_execute, kernel, , callout_start, 0, 74 "struct callout *"); 75 SDT_PROBE_DEFINE(callout_execute, kernel, , callout_end, callout-end); 76 SDT_PROBE_ARGTYPE(callout_execute, kernel, , callout_end, 0, 77 "struct callout *"); 78 79 #ifdef CALLOUT_PROFILING 80 static int avg_depth; 81 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, 82 "Average number of items examined per softclock call. Units = 1/1000"); 83 static int avg_gcalls; 84 SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, 85 "Average number of Giant callouts made per softclock call. Units = 1/1000"); 86 static int avg_lockcalls; 87 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0, 88 "Average number of lock callouts made per softclock call. Units = 1/1000"); 89 static int avg_mpcalls; 90 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, 91 "Average number of MP callouts made per softclock call. Units = 1/1000"); 92 static int avg_depth_dir; 93 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0, 94 "Average number of direct callouts examined per callout_process call. " 95 "Units = 1/1000"); 96 static int avg_lockcalls_dir; 97 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD, 98 &avg_lockcalls_dir, 0, "Average number of lock direct callouts made per " 99 "callout_process call. Units = 1/1000"); 100 static int avg_mpcalls_dir; 101 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir, 102 0, "Average number of MP direct callouts made per callout_process call. " 103 "Units = 1/1000"); 104 #endif 105 106 static int ncallout; 107 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN, &ncallout, 0, 108 "Number of entries in callwheel and size of timeout() preallocation"); 109 110 /* 111 * TODO: 112 * allocate more timeout table slots when table overflows. 113 */ 114 u_int callwheelsize, callwheelmask; 115 116 /* 117 * The callout cpu exec entities represent informations necessary for 118 * describing the state of callouts currently running on the CPU and the ones 119 * necessary for migrating callouts to the new callout cpu. In particular, 120 * the first entry of the array cc_exec_entity holds informations for callout 121 * running in SWI thread context, while the second one holds informations 122 * for callout running directly from hardware interrupt context. 123 * The cached informations are very important for deferring migration when 124 * the migrating callout is already running. 125 */ 126 struct cc_exec { 127 struct callout *cc_next; 128 struct callout *cc_curr; 129 #ifdef SMP 130 void (*ce_migration_func)(void *); 131 void *ce_migration_arg; 132 int ce_migration_cpu; 133 sbintime_t ce_migration_time; 134 sbintime_t ce_migration_prec; 135 #endif 136 bool cc_cancel; 137 bool cc_waiting; 138 }; 139 140 /* 141 * There is one struct callout_cpu per cpu, holding all relevant 142 * state for the callout processing thread on the individual CPU. 143 */ 144 struct callout_cpu { 145 struct mtx_padalign cc_lock; 146 struct cc_exec cc_exec_entity[2]; 147 struct callout *cc_callout; 148 struct callout_list *cc_callwheel; 149 struct callout_tailq cc_expireq; 150 struct callout_slist cc_callfree; 151 sbintime_t cc_firstevent; 152 sbintime_t cc_lastscan; 153 void *cc_cookie; 154 u_int cc_bucket; 155 }; 156 157 #define cc_exec_curr cc_exec_entity[0].cc_curr 158 #define cc_exec_next cc_exec_entity[0].cc_next 159 #define cc_exec_cancel cc_exec_entity[0].cc_cancel 160 #define cc_exec_waiting cc_exec_entity[0].cc_waiting 161 #define cc_exec_curr_dir cc_exec_entity[1].cc_curr 162 #define cc_exec_next_dir cc_exec_entity[1].cc_next 163 #define cc_exec_cancel_dir cc_exec_entity[1].cc_cancel 164 #define cc_exec_waiting_dir cc_exec_entity[1].cc_waiting 165 166 #ifdef SMP 167 #define cc_migration_func cc_exec_entity[0].ce_migration_func 168 #define cc_migration_arg cc_exec_entity[0].ce_migration_arg 169 #define cc_migration_cpu cc_exec_entity[0].ce_migration_cpu 170 #define cc_migration_time cc_exec_entity[0].ce_migration_time 171 #define cc_migration_prec cc_exec_entity[0].ce_migration_prec 172 #define cc_migration_func_dir cc_exec_entity[1].ce_migration_func 173 #define cc_migration_arg_dir cc_exec_entity[1].ce_migration_arg 174 #define cc_migration_cpu_dir cc_exec_entity[1].ce_migration_cpu 175 #define cc_migration_time_dir cc_exec_entity[1].ce_migration_time 176 #define cc_migration_prec_dir cc_exec_entity[1].ce_migration_prec 177 178 struct callout_cpu cc_cpu[MAXCPU]; 179 #define CPUBLOCK MAXCPU 180 #define CC_CPU(cpu) (&cc_cpu[(cpu)]) 181 #define CC_SELF() CC_CPU(PCPU_GET(cpuid)) 182 #else 183 struct callout_cpu cc_cpu; 184 #define CC_CPU(cpu) &cc_cpu 185 #define CC_SELF() &cc_cpu 186 #endif 187 #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) 188 #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) 189 #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) 190 191 static int timeout_cpu; 192 193 static void callout_cpu_init(struct callout_cpu *cc); 194 static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, 195 #ifdef CALLOUT_PROFILING 196 int *mpcalls, int *lockcalls, int *gcalls, 197 #endif 198 int direct); 199 200 static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); 201 202 /** 203 * Locked by cc_lock: 204 * cc_curr - If a callout is in progress, it is cc_curr. 205 * If cc_curr is non-NULL, threads waiting in 206 * callout_drain() will be woken up as soon as the 207 * relevant callout completes. 208 * cc_cancel - Changing to 1 with both callout_lock and cc_lock held 209 * guarantees that the current callout will not run. 210 * The softclock() function sets this to 0 before it 211 * drops callout_lock to acquire c_lock, and it calls 212 * the handler only if curr_cancelled is still 0 after 213 * cc_lock is successfully acquired. 214 * cc_waiting - If a thread is waiting in callout_drain(), then 215 * callout_wait is nonzero. Set only when 216 * cc_curr is non-NULL. 217 */ 218 219 /* 220 * Resets the execution entity tied to a specific callout cpu. 221 */ 222 static void 223 cc_cce_cleanup(struct callout_cpu *cc, int direct) 224 { 225 226 cc->cc_exec_entity[direct].cc_curr = NULL; 227 cc->cc_exec_entity[direct].cc_next = NULL; 228 cc->cc_exec_entity[direct].cc_cancel = false; 229 cc->cc_exec_entity[direct].cc_waiting = false; 230 #ifdef SMP 231 cc->cc_exec_entity[direct].ce_migration_cpu = CPUBLOCK; 232 cc->cc_exec_entity[direct].ce_migration_time = 0; 233 cc->cc_exec_entity[direct].ce_migration_prec = 0; 234 cc->cc_exec_entity[direct].ce_migration_func = NULL; 235 cc->cc_exec_entity[direct].ce_migration_arg = NULL; 236 #endif 237 } 238 239 /* 240 * Checks if migration is requested by a specific callout cpu. 241 */ 242 static int 243 cc_cce_migrating(struct callout_cpu *cc, int direct) 244 { 245 246 #ifdef SMP 247 return (cc->cc_exec_entity[direct].ce_migration_cpu != CPUBLOCK); 248 #else 249 return (0); 250 #endif 251 } 252 253 /* 254 * Kernel low level callwheel initialization 255 * called on cpu0 during kernel startup. 256 */ 257 static void 258 callout_callwheel_init(void *dummy) 259 { 260 struct callout_cpu *cc; 261 262 /* 263 * Calculate the size of the callout wheel and the preallocated 264 * timeout() structures. 265 * XXX: Clip callout to result of previous function of maxusers 266 * maximum 384. This is still huge, but acceptable. 267 */ 268 ncallout = imin(16 + maxproc + maxfiles, 18508); 269 TUNABLE_INT_FETCH("kern.ncallout", &ncallout); 270 271 /* 272 * Calculate callout wheel size, should be next power of two higher 273 * than 'ncallout'. 274 */ 275 callwheelsize = 1 << fls(ncallout); 276 callwheelmask = callwheelsize - 1; 277 278 /* 279 * Only cpu0 handles timeout(9) and receives a preallocation. 280 * 281 * XXX: Once all timeout(9) consumers are converted this can 282 * be removed. 283 */ 284 timeout_cpu = PCPU_GET(cpuid); 285 cc = CC_CPU(timeout_cpu); 286 cc->cc_callout = malloc(ncallout * sizeof(struct callout), 287 M_CALLOUT, M_WAITOK); 288 callout_cpu_init(cc); 289 } 290 SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); 291 292 /* 293 * Initialize the per-cpu callout structures. 294 */ 295 static void 296 callout_cpu_init(struct callout_cpu *cc) 297 { 298 struct callout *c; 299 int i; 300 301 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); 302 SLIST_INIT(&cc->cc_callfree); 303 cc->cc_callwheel = malloc(sizeof(struct callout_list) * callwheelsize, 304 M_CALLOUT, M_WAITOK); 305 for (i = 0; i < callwheelsize; i++) 306 LIST_INIT(&cc->cc_callwheel[i]); 307 TAILQ_INIT(&cc->cc_expireq); 308 cc->cc_firstevent = INT64_MAX; 309 for (i = 0; i < 2; i++) 310 cc_cce_cleanup(cc, i); 311 if (cc->cc_callout == NULL) /* Only cpu0 handles timeout(9) */ 312 return; 313 for (i = 0; i < ncallout; i++) { 314 c = &cc->cc_callout[i]; 315 callout_init(c, 0); 316 c->c_flags = CALLOUT_LOCAL_ALLOC; 317 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 318 } 319 } 320 321 #ifdef SMP 322 /* 323 * Switches the cpu tied to a specific callout. 324 * The function expects a locked incoming callout cpu and returns with 325 * locked outcoming callout cpu. 326 */ 327 static struct callout_cpu * 328 callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu) 329 { 330 struct callout_cpu *new_cc; 331 332 MPASS(c != NULL && cc != NULL); 333 CC_LOCK_ASSERT(cc); 334 335 /* 336 * Avoid interrupts and preemption firing after the callout cpu 337 * is blocked in order to avoid deadlocks as the new thread 338 * may be willing to acquire the callout cpu lock. 339 */ 340 c->c_cpu = CPUBLOCK; 341 spinlock_enter(); 342 CC_UNLOCK(cc); 343 new_cc = CC_CPU(new_cpu); 344 CC_LOCK(new_cc); 345 spinlock_exit(); 346 c->c_cpu = new_cpu; 347 return (new_cc); 348 } 349 #endif 350 351 /* 352 * Start standard softclock thread. 353 */ 354 static void 355 start_softclock(void *dummy) 356 { 357 struct callout_cpu *cc; 358 #ifdef SMP 359 int cpu; 360 #endif 361 362 cc = CC_CPU(timeout_cpu); 363 if (swi_add(&clk_intr_event, "clock", softclock, cc, SWI_CLOCK, 364 INTR_MPSAFE, &cc->cc_cookie)) 365 panic("died while creating standard software ithreads"); 366 #ifdef SMP 367 CPU_FOREACH(cpu) { 368 if (cpu == timeout_cpu) 369 continue; 370 cc = CC_CPU(cpu); 371 cc->cc_callout = NULL; /* Only cpu0 handles timeout(9). */ 372 callout_cpu_init(cc); 373 if (swi_add(NULL, "clock", softclock, cc, SWI_CLOCK, 374 INTR_MPSAFE, &cc->cc_cookie)) 375 panic("died while creating standard software ithreads"); 376 } 377 #endif 378 } 379 SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL); 380 381 #define CC_HASH_SHIFT 8 382 383 static inline u_int 384 callout_hash(sbintime_t sbt) 385 { 386 387 return (sbt >> (32 - CC_HASH_SHIFT)); 388 } 389 390 static inline u_int 391 callout_get_bucket(sbintime_t sbt) 392 { 393 394 return (callout_hash(sbt) & callwheelmask); 395 } 396 397 void 398 callout_process(sbintime_t now) 399 { 400 struct callout *tmp, *tmpn; 401 struct callout_cpu *cc; 402 struct callout_list *sc; 403 sbintime_t first, last, max, tmp_max; 404 uint32_t lookahead; 405 u_int firstb, lastb, nowb; 406 #ifdef CALLOUT_PROFILING 407 int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0; 408 #endif 409 410 cc = CC_SELF(); 411 mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET); 412 413 /* Compute the buckets of the last scan and present times. */ 414 firstb = callout_hash(cc->cc_lastscan); 415 cc->cc_lastscan = now; 416 nowb = callout_hash(now); 417 418 /* Compute the last bucket and minimum time of the bucket after it. */ 419 if (nowb == firstb) 420 lookahead = (SBT_1S / 16); 421 else if (nowb - firstb == 1) 422 lookahead = (SBT_1S / 8); 423 else 424 lookahead = (SBT_1S / 2); 425 first = last = now; 426 first += (lookahead / 2); 427 last += lookahead; 428 last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT)); 429 lastb = callout_hash(last) - 1; 430 max = last; 431 432 /* 433 * Check if we wrapped around the entire wheel from the last scan. 434 * In case, we need to scan entirely the wheel for pending callouts. 435 */ 436 if (lastb - firstb >= callwheelsize) { 437 lastb = firstb + callwheelsize - 1; 438 if (nowb - firstb >= callwheelsize) 439 nowb = lastb; 440 } 441 442 /* Iterate callwheel from firstb to nowb and then up to lastb. */ 443 do { 444 sc = &cc->cc_callwheel[firstb & callwheelmask]; 445 tmp = LIST_FIRST(sc); 446 while (tmp != NULL) { 447 /* Run the callout if present time within allowed. */ 448 if (tmp->c_time <= now) { 449 /* 450 * Consumer told us the callout may be run 451 * directly from hardware interrupt context. 452 */ 453 if (tmp->c_flags & CALLOUT_DIRECT) { 454 #ifdef CALLOUT_PROFILING 455 ++depth_dir; 456 #endif 457 cc->cc_exec_next_dir = 458 LIST_NEXT(tmp, c_links.le); 459 cc->cc_bucket = firstb & callwheelmask; 460 LIST_REMOVE(tmp, c_links.le); 461 softclock_call_cc(tmp, cc, 462 #ifdef CALLOUT_PROFILING 463 &mpcalls_dir, &lockcalls_dir, NULL, 464 #endif 465 1); 466 tmp = cc->cc_exec_next_dir; 467 } else { 468 tmpn = LIST_NEXT(tmp, c_links.le); 469 LIST_REMOVE(tmp, c_links.le); 470 TAILQ_INSERT_TAIL(&cc->cc_expireq, 471 tmp, c_links.tqe); 472 tmp->c_flags |= CALLOUT_PROCESSED; 473 tmp = tmpn; 474 } 475 continue; 476 } 477 /* Skip events from distant future. */ 478 if (tmp->c_time >= max) 479 goto next; 480 /* 481 * Event minimal time is bigger than present maximal 482 * time, so it cannot be aggregated. 483 */ 484 if (tmp->c_time > last) { 485 lastb = nowb; 486 goto next; 487 } 488 /* Update first and last time, respecting this event. */ 489 if (tmp->c_time < first) 490 first = tmp->c_time; 491 tmp_max = tmp->c_time + tmp->c_precision; 492 if (tmp_max < last) 493 last = tmp_max; 494 next: 495 tmp = LIST_NEXT(tmp, c_links.le); 496 } 497 /* Proceed with the next bucket. */ 498 firstb++; 499 /* 500 * Stop if we looked after present time and found 501 * some event we can't execute at now. 502 * Stop if we looked far enough into the future. 503 */ 504 } while (((int)(firstb - lastb)) <= 0); 505 cc->cc_firstevent = last; 506 #ifndef NO_EVENTTIMERS 507 cpu_new_callout(curcpu, last, first); 508 #endif 509 #ifdef CALLOUT_PROFILING 510 avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8; 511 avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8; 512 avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8; 513 #endif 514 mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET); 515 /* 516 * swi_sched acquires the thread lock, so we don't want to call it 517 * with cc_lock held; incorrect locking order. 518 */ 519 if (!TAILQ_EMPTY(&cc->cc_expireq)) 520 swi_sched(cc->cc_cookie, 0); 521 } 522 523 static struct callout_cpu * 524 callout_lock(struct callout *c) 525 { 526 struct callout_cpu *cc; 527 int cpu; 528 529 for (;;) { 530 cpu = c->c_cpu; 531 #ifdef SMP 532 if (cpu == CPUBLOCK) { 533 while (c->c_cpu == CPUBLOCK) 534 cpu_spinwait(); 535 continue; 536 } 537 #endif 538 cc = CC_CPU(cpu); 539 CC_LOCK(cc); 540 if (cpu == c->c_cpu) 541 break; 542 CC_UNLOCK(cc); 543 } 544 return (cc); 545 } 546 547 static void 548 callout_cc_add(struct callout *c, struct callout_cpu *cc, 549 sbintime_t sbt, sbintime_t precision, void (*func)(void *), 550 void *arg, int cpu, int flags) 551 { 552 int bucket; 553 554 CC_LOCK_ASSERT(cc); 555 if (sbt < cc->cc_lastscan) 556 sbt = cc->cc_lastscan; 557 c->c_arg = arg; 558 c->c_flags |= (CALLOUT_ACTIVE | CALLOUT_PENDING); 559 if (flags & C_DIRECT_EXEC) 560 c->c_flags |= CALLOUT_DIRECT; 561 c->c_flags &= ~CALLOUT_PROCESSED; 562 c->c_func = func; 563 c->c_time = sbt; 564 c->c_precision = precision; 565 bucket = callout_get_bucket(c->c_time); 566 CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x", 567 c, (int)(c->c_precision >> 32), 568 (u_int)(c->c_precision & 0xffffffff)); 569 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); 570 if (cc->cc_bucket == bucket) 571 cc->cc_exec_next_dir = c; 572 #ifndef NO_EVENTTIMERS 573 /* 574 * Inform the eventtimers(4) subsystem there's a new callout 575 * that has been inserted, but only if really required. 576 */ 577 sbt = c->c_time + c->c_precision; 578 if (sbt < cc->cc_firstevent) { 579 cc->cc_firstevent = sbt; 580 cpu_new_callout(cpu, sbt, c->c_time); 581 } 582 #endif 583 } 584 585 static void 586 callout_cc_del(struct callout *c, struct callout_cpu *cc) 587 { 588 589 if ((c->c_flags & CALLOUT_LOCAL_ALLOC) == 0) 590 return; 591 c->c_func = NULL; 592 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 593 } 594 595 static void 596 softclock_call_cc(struct callout *c, struct callout_cpu *cc, 597 #ifdef CALLOUT_PROFILING 598 int *mpcalls, int *lockcalls, int *gcalls, 599 #endif 600 int direct) 601 { 602 void (*c_func)(void *); 603 void *c_arg; 604 struct lock_class *class; 605 struct lock_object *c_lock; 606 int c_flags, sharedlock; 607 #ifdef SMP 608 struct callout_cpu *new_cc; 609 void (*new_func)(void *); 610 void *new_arg; 611 int flags, new_cpu; 612 sbintime_t new_prec, new_time; 613 #endif 614 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 615 sbintime_t sbt1, sbt2; 616 struct timespec ts2; 617 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 618 static timeout_t *lastfunc; 619 #endif 620 621 KASSERT((c->c_flags & (CALLOUT_PENDING | CALLOUT_ACTIVE)) == 622 (CALLOUT_PENDING | CALLOUT_ACTIVE), 623 ("softclock_call_cc: pend|act %p %x", c, c->c_flags)); 624 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; 625 sharedlock = (c->c_flags & CALLOUT_SHAREDLOCK) ? 0 : 1; 626 c_lock = c->c_lock; 627 c_func = c->c_func; 628 c_arg = c->c_arg; 629 c_flags = c->c_flags; 630 if (c->c_flags & CALLOUT_LOCAL_ALLOC) 631 c->c_flags = CALLOUT_LOCAL_ALLOC; 632 else 633 c->c_flags &= ~CALLOUT_PENDING; 634 cc->cc_exec_entity[direct].cc_curr = c; 635 cc->cc_exec_entity[direct].cc_cancel = false; 636 CC_UNLOCK(cc); 637 if (c_lock != NULL) { 638 class->lc_lock(c_lock, sharedlock); 639 /* 640 * The callout may have been cancelled 641 * while we switched locks. 642 */ 643 if (cc->cc_exec_entity[direct].cc_cancel) { 644 class->lc_unlock(c_lock); 645 goto skip; 646 } 647 /* The callout cannot be stopped now. */ 648 cc->cc_exec_entity[direct].cc_cancel = true; 649 if (c_lock == &Giant.lock_object) { 650 #ifdef CALLOUT_PROFILING 651 (*gcalls)++; 652 #endif 653 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", 654 c, c_func, c_arg); 655 } else { 656 #ifdef CALLOUT_PROFILING 657 (*lockcalls)++; 658 #endif 659 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", 660 c, c_func, c_arg); 661 } 662 } else { 663 #ifdef CALLOUT_PROFILING 664 (*mpcalls)++; 665 #endif 666 CTR3(KTR_CALLOUT, "callout %p func %p arg %p", 667 c, c_func, c_arg); 668 } 669 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 670 sbt1 = sbinuptime(); 671 #endif 672 THREAD_NO_SLEEPING(); 673 SDT_PROBE(callout_execute, kernel, , callout_start, c, 0, 0, 0, 0); 674 c_func(c_arg); 675 SDT_PROBE(callout_execute, kernel, , callout_end, c, 0, 0, 0, 0); 676 THREAD_SLEEPING_OK(); 677 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 678 sbt2 = sbinuptime(); 679 sbt2 -= sbt1; 680 if (sbt2 > maxdt) { 681 if (lastfunc != c_func || sbt2 > maxdt * 2) { 682 ts2 = sbttots(sbt2); 683 printf( 684 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 685 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); 686 } 687 maxdt = sbt2; 688 lastfunc = c_func; 689 } 690 #endif 691 CTR1(KTR_CALLOUT, "callout %p finished", c); 692 if ((c_flags & CALLOUT_RETURNUNLOCKED) == 0) 693 class->lc_unlock(c_lock); 694 skip: 695 CC_LOCK(cc); 696 KASSERT(cc->cc_exec_entity[direct].cc_curr == c, ("mishandled cc_curr")); 697 cc->cc_exec_entity[direct].cc_curr = NULL; 698 if (cc->cc_exec_entity[direct].cc_waiting) { 699 /* 700 * There is someone waiting for the 701 * callout to complete. 702 * If the callout was scheduled for 703 * migration just cancel it. 704 */ 705 if (cc_cce_migrating(cc, direct)) { 706 cc_cce_cleanup(cc, direct); 707 708 /* 709 * It should be assert here that the callout is not 710 * destroyed but that is not easy. 711 */ 712 c->c_flags &= ~CALLOUT_DFRMIGRATION; 713 } 714 cc->cc_exec_entity[direct].cc_waiting = false; 715 CC_UNLOCK(cc); 716 wakeup(&cc->cc_exec_entity[direct].cc_waiting); 717 CC_LOCK(cc); 718 } else if (cc_cce_migrating(cc, direct)) { 719 KASSERT((c_flags & CALLOUT_LOCAL_ALLOC) == 0, 720 ("Migrating legacy callout %p", c)); 721 #ifdef SMP 722 /* 723 * If the callout was scheduled for 724 * migration just perform it now. 725 */ 726 new_cpu = cc->cc_exec_entity[direct].ce_migration_cpu; 727 new_time = cc->cc_exec_entity[direct].ce_migration_time; 728 new_prec = cc->cc_exec_entity[direct].ce_migration_prec; 729 new_func = cc->cc_exec_entity[direct].ce_migration_func; 730 new_arg = cc->cc_exec_entity[direct].ce_migration_arg; 731 cc_cce_cleanup(cc, direct); 732 733 /* 734 * It should be assert here that the callout is not destroyed 735 * but that is not easy. 736 * 737 * As first thing, handle deferred callout stops. 738 */ 739 if ((c->c_flags & CALLOUT_DFRMIGRATION) == 0) { 740 CTR3(KTR_CALLOUT, 741 "deferred cancelled %p func %p arg %p", 742 c, new_func, new_arg); 743 callout_cc_del(c, cc); 744 return; 745 } 746 c->c_flags &= ~CALLOUT_DFRMIGRATION; 747 748 new_cc = callout_cpu_switch(c, cc, new_cpu); 749 flags = (direct) ? C_DIRECT_EXEC : 0; 750 callout_cc_add(c, new_cc, new_time, new_prec, new_func, 751 new_arg, new_cpu, flags); 752 CC_UNLOCK(new_cc); 753 CC_LOCK(cc); 754 #else 755 panic("migration should not happen"); 756 #endif 757 } 758 /* 759 * If the current callout is locally allocated (from 760 * timeout(9)) then put it on the freelist. 761 * 762 * Note: we need to check the cached copy of c_flags because 763 * if it was not local, then it's not safe to deref the 764 * callout pointer. 765 */ 766 KASSERT((c_flags & CALLOUT_LOCAL_ALLOC) == 0 || 767 c->c_flags == CALLOUT_LOCAL_ALLOC, 768 ("corrupted callout")); 769 if (c_flags & CALLOUT_LOCAL_ALLOC) 770 callout_cc_del(c, cc); 771 } 772 773 /* 774 * The callout mechanism is based on the work of Adam M. Costello and 775 * George Varghese, published in a technical report entitled "Redesigning 776 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 777 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 778 * used in this implementation was published by G. Varghese and T. Lauck in 779 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 780 * the Efficient Implementation of a Timer Facility" in the Proceedings of 781 * the 11th ACM Annual Symposium on Operating Systems Principles, 782 * Austin, Texas Nov 1987. 783 */ 784 785 /* 786 * Software (low priority) clock interrupt. 787 * Run periodic events from timeout queue. 788 */ 789 void 790 softclock(void *arg) 791 { 792 struct callout_cpu *cc; 793 struct callout *c; 794 #ifdef CALLOUT_PROFILING 795 int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0; 796 #endif 797 798 cc = (struct callout_cpu *)arg; 799 CC_LOCK(cc); 800 while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) { 801 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 802 softclock_call_cc(c, cc, 803 #ifdef CALLOUT_PROFILING 804 &mpcalls, &lockcalls, &gcalls, 805 #endif 806 0); 807 #ifdef CALLOUT_PROFILING 808 ++depth; 809 #endif 810 } 811 #ifdef CALLOUT_PROFILING 812 avg_depth += (depth * 1000 - avg_depth) >> 8; 813 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 814 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 815 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 816 #endif 817 CC_UNLOCK(cc); 818 } 819 820 /* 821 * timeout -- 822 * Execute a function after a specified length of time. 823 * 824 * untimeout -- 825 * Cancel previous timeout function call. 826 * 827 * callout_handle_init -- 828 * Initialize a handle so that using it with untimeout is benign. 829 * 830 * See AT&T BCI Driver Reference Manual for specification. This 831 * implementation differs from that one in that although an 832 * identification value is returned from timeout, the original 833 * arguments to timeout as well as the identifier are used to 834 * identify entries for untimeout. 835 */ 836 struct callout_handle 837 timeout(ftn, arg, to_ticks) 838 timeout_t *ftn; 839 void *arg; 840 int to_ticks; 841 { 842 struct callout_cpu *cc; 843 struct callout *new; 844 struct callout_handle handle; 845 846 cc = CC_CPU(timeout_cpu); 847 CC_LOCK(cc); 848 /* Fill in the next free callout structure. */ 849 new = SLIST_FIRST(&cc->cc_callfree); 850 if (new == NULL) 851 /* XXX Attempt to malloc first */ 852 panic("timeout table full"); 853 SLIST_REMOVE_HEAD(&cc->cc_callfree, c_links.sle); 854 callout_reset(new, to_ticks, ftn, arg); 855 handle.callout = new; 856 CC_UNLOCK(cc); 857 858 return (handle); 859 } 860 861 void 862 untimeout(ftn, arg, handle) 863 timeout_t *ftn; 864 void *arg; 865 struct callout_handle handle; 866 { 867 struct callout_cpu *cc; 868 869 /* 870 * Check for a handle that was initialized 871 * by callout_handle_init, but never used 872 * for a real timeout. 873 */ 874 if (handle.callout == NULL) 875 return; 876 877 cc = callout_lock(handle.callout); 878 if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) 879 callout_stop(handle.callout); 880 CC_UNLOCK(cc); 881 } 882 883 void 884 callout_handle_init(struct callout_handle *handle) 885 { 886 handle->callout = NULL; 887 } 888 889 /* 890 * New interface; clients allocate their own callout structures. 891 * 892 * callout_reset() - establish or change a timeout 893 * callout_stop() - disestablish a timeout 894 * callout_init() - initialize a callout structure so that it can 895 * safely be passed to callout_reset() and callout_stop() 896 * 897 * <sys/callout.h> defines three convenience macros: 898 * 899 * callout_active() - returns truth if callout has not been stopped, 900 * drained, or deactivated since the last time the callout was 901 * reset. 902 * callout_pending() - returns truth if callout is still waiting for timeout 903 * callout_deactivate() - marks the callout as having been serviced 904 */ 905 int 906 callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t precision, 907 void (*ftn)(void *), void *arg, int cpu, int flags) 908 { 909 sbintime_t to_sbt, pr; 910 struct callout_cpu *cc; 911 int cancelled, direct; 912 913 cancelled = 0; 914 if (flags & C_ABSOLUTE) { 915 to_sbt = sbt; 916 } else { 917 if ((flags & C_HARDCLOCK) && (sbt < tick_sbt)) 918 sbt = tick_sbt; 919 if ((flags & C_HARDCLOCK) || 920 #ifdef NO_EVENTTIMERS 921 sbt >= sbt_timethreshold) { 922 to_sbt = getsbinuptime(); 923 924 /* Add safety belt for the case of hz > 1000. */ 925 to_sbt += tc_tick_sbt - tick_sbt; 926 #else 927 sbt >= sbt_tickthreshold) { 928 /* 929 * Obtain the time of the last hardclock() call on 930 * this CPU directly from the kern_clocksource.c. 931 * This value is per-CPU, but it is equal for all 932 * active ones. 933 */ 934 #ifdef __LP64__ 935 to_sbt = DPCPU_GET(hardclocktime); 936 #else 937 spinlock_enter(); 938 to_sbt = DPCPU_GET(hardclocktime); 939 spinlock_exit(); 940 #endif 941 #endif 942 if ((flags & C_HARDCLOCK) == 0) 943 to_sbt += tick_sbt; 944 } else 945 to_sbt = sbinuptime(); 946 to_sbt += sbt; 947 pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : 948 sbt >> C_PRELGET(flags)); 949 if (pr > precision) 950 precision = pr; 951 } 952 /* 953 * Don't allow migration of pre-allocated callouts lest they 954 * become unbalanced. 955 */ 956 if (c->c_flags & CALLOUT_LOCAL_ALLOC) 957 cpu = c->c_cpu; 958 direct = (c->c_flags & CALLOUT_DIRECT) != 0; 959 KASSERT(!direct || c->c_lock == NULL, 960 ("%s: direct callout %p has lock", __func__, c)); 961 cc = callout_lock(c); 962 if (cc->cc_exec_entity[direct].cc_curr == c) { 963 /* 964 * We're being asked to reschedule a callout which is 965 * currently in progress. If there is a lock then we 966 * can cancel the callout if it has not really started. 967 */ 968 if (c->c_lock != NULL && !cc->cc_exec_entity[direct].cc_cancel) 969 cancelled = cc->cc_exec_entity[direct].cc_cancel = true; 970 if (cc->cc_exec_entity[direct].cc_waiting) { 971 /* 972 * Someone has called callout_drain to kill this 973 * callout. Don't reschedule. 974 */ 975 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 976 cancelled ? "cancelled" : "failed to cancel", 977 c, c->c_func, c->c_arg); 978 CC_UNLOCK(cc); 979 return (cancelled); 980 } 981 } 982 if (c->c_flags & CALLOUT_PENDING) { 983 if ((c->c_flags & CALLOUT_PROCESSED) == 0) { 984 if (cc->cc_exec_next_dir == c) 985 cc->cc_exec_next_dir = LIST_NEXT(c, c_links.le); 986 LIST_REMOVE(c, c_links.le); 987 } else 988 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 989 cancelled = 1; 990 c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING); 991 } 992 993 #ifdef SMP 994 /* 995 * If the callout must migrate try to perform it immediately. 996 * If the callout is currently running, just defer the migration 997 * to a more appropriate moment. 998 */ 999 if (c->c_cpu != cpu) { 1000 if (cc->cc_exec_entity[direct].cc_curr == c) { 1001 cc->cc_exec_entity[direct].ce_migration_cpu = cpu; 1002 cc->cc_exec_entity[direct].ce_migration_time 1003 = to_sbt; 1004 cc->cc_exec_entity[direct].ce_migration_prec 1005 = precision; 1006 cc->cc_exec_entity[direct].ce_migration_func = ftn; 1007 cc->cc_exec_entity[direct].ce_migration_arg = arg; 1008 c->c_flags |= CALLOUT_DFRMIGRATION; 1009 CTR6(KTR_CALLOUT, 1010 "migration of %p func %p arg %p in %d.%08x to %u deferred", 1011 c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1012 (u_int)(to_sbt & 0xffffffff), cpu); 1013 CC_UNLOCK(cc); 1014 return (cancelled); 1015 } 1016 cc = callout_cpu_switch(c, cc, cpu); 1017 } 1018 #endif 1019 1020 callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags); 1021 CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x", 1022 cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32), 1023 (u_int)(to_sbt & 0xffffffff)); 1024 CC_UNLOCK(cc); 1025 1026 return (cancelled); 1027 } 1028 1029 /* 1030 * Common idioms that can be optimized in the future. 1031 */ 1032 int 1033 callout_schedule_on(struct callout *c, int to_ticks, int cpu) 1034 { 1035 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 1036 } 1037 1038 int 1039 callout_schedule(struct callout *c, int to_ticks) 1040 { 1041 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 1042 } 1043 1044 int 1045 _callout_stop_safe(c, safe) 1046 struct callout *c; 1047 int safe; 1048 { 1049 struct callout_cpu *cc, *old_cc; 1050 struct lock_class *class; 1051 int direct, sq_locked, use_lock; 1052 1053 /* 1054 * Some old subsystems don't hold Giant while running a callout_stop(), 1055 * so just discard this check for the moment. 1056 */ 1057 if (!safe && c->c_lock != NULL) { 1058 if (c->c_lock == &Giant.lock_object) 1059 use_lock = mtx_owned(&Giant); 1060 else { 1061 use_lock = 1; 1062 class = LOCK_CLASS(c->c_lock); 1063 class->lc_assert(c->c_lock, LA_XLOCKED); 1064 } 1065 } else 1066 use_lock = 0; 1067 direct = (c->c_flags & CALLOUT_DIRECT) != 0; 1068 sq_locked = 0; 1069 old_cc = NULL; 1070 again: 1071 cc = callout_lock(c); 1072 1073 /* 1074 * If the callout was migrating while the callout cpu lock was 1075 * dropped, just drop the sleepqueue lock and check the states 1076 * again. 1077 */ 1078 if (sq_locked != 0 && cc != old_cc) { 1079 #ifdef SMP 1080 CC_UNLOCK(cc); 1081 sleepq_release(&old_cc->cc_exec_entity[direct].cc_waiting); 1082 sq_locked = 0; 1083 old_cc = NULL; 1084 goto again; 1085 #else 1086 panic("migration should not happen"); 1087 #endif 1088 } 1089 1090 /* 1091 * If the callout isn't pending, it's not on the queue, so 1092 * don't attempt to remove it from the queue. We can try to 1093 * stop it by other means however. 1094 */ 1095 if (!(c->c_flags & CALLOUT_PENDING)) { 1096 c->c_flags &= ~CALLOUT_ACTIVE; 1097 1098 /* 1099 * If it wasn't on the queue and it isn't the current 1100 * callout, then we can't stop it, so just bail. 1101 */ 1102 if (cc->cc_exec_entity[direct].cc_curr != c) { 1103 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1104 c, c->c_func, c->c_arg); 1105 CC_UNLOCK(cc); 1106 if (sq_locked) 1107 sleepq_release( 1108 &cc->cc_exec_entity[direct].cc_waiting); 1109 return (0); 1110 } 1111 1112 if (safe) { 1113 /* 1114 * The current callout is running (or just 1115 * about to run) and blocking is allowed, so 1116 * just wait for the current invocation to 1117 * finish. 1118 */ 1119 while (cc->cc_exec_entity[direct].cc_curr == c) { 1120 /* 1121 * Use direct calls to sleepqueue interface 1122 * instead of cv/msleep in order to avoid 1123 * a LOR between cc_lock and sleepqueue 1124 * chain spinlocks. This piece of code 1125 * emulates a msleep_spin() call actually. 1126 * 1127 * If we already have the sleepqueue chain 1128 * locked, then we can safely block. If we 1129 * don't already have it locked, however, 1130 * we have to drop the cc_lock to lock 1131 * it. This opens several races, so we 1132 * restart at the beginning once we have 1133 * both locks. If nothing has changed, then 1134 * we will end up back here with sq_locked 1135 * set. 1136 */ 1137 if (!sq_locked) { 1138 CC_UNLOCK(cc); 1139 sleepq_lock( 1140 &cc->cc_exec_entity[direct].cc_waiting); 1141 sq_locked = 1; 1142 old_cc = cc; 1143 goto again; 1144 } 1145 1146 /* 1147 * Migration could be cancelled here, but 1148 * as long as it is still not sure when it 1149 * will be packed up, just let softclock() 1150 * take care of it. 1151 */ 1152 cc->cc_exec_entity[direct].cc_waiting = true; 1153 DROP_GIANT(); 1154 CC_UNLOCK(cc); 1155 sleepq_add( 1156 &cc->cc_exec_entity[direct].cc_waiting, 1157 &cc->cc_lock.lock_object, "codrain", 1158 SLEEPQ_SLEEP, 0); 1159 sleepq_wait( 1160 &cc->cc_exec_entity[direct].cc_waiting, 1161 0); 1162 sq_locked = 0; 1163 old_cc = NULL; 1164 1165 /* Reacquire locks previously released. */ 1166 PICKUP_GIANT(); 1167 CC_LOCK(cc); 1168 } 1169 } else if (use_lock && 1170 !cc->cc_exec_entity[direct].cc_cancel) { 1171 /* 1172 * The current callout is waiting for its 1173 * lock which we hold. Cancel the callout 1174 * and return. After our caller drops the 1175 * lock, the callout will be skipped in 1176 * softclock(). 1177 */ 1178 cc->cc_exec_entity[direct].cc_cancel = true; 1179 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1180 c, c->c_func, c->c_arg); 1181 KASSERT(!cc_cce_migrating(cc, direct), 1182 ("callout wrongly scheduled for migration")); 1183 CC_UNLOCK(cc); 1184 KASSERT(!sq_locked, ("sleepqueue chain locked")); 1185 return (1); 1186 } else if ((c->c_flags & CALLOUT_DFRMIGRATION) != 0) { 1187 c->c_flags &= ~CALLOUT_DFRMIGRATION; 1188 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 1189 c, c->c_func, c->c_arg); 1190 CC_UNLOCK(cc); 1191 return (1); 1192 } 1193 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 1194 c, c->c_func, c->c_arg); 1195 CC_UNLOCK(cc); 1196 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 1197 return (0); 1198 } 1199 if (sq_locked) 1200 sleepq_release(&cc->cc_exec_entity[direct].cc_waiting); 1201 1202 c->c_flags &= ~(CALLOUT_ACTIVE | CALLOUT_PENDING); 1203 1204 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 1205 c, c->c_func, c->c_arg); 1206 if ((c->c_flags & CALLOUT_PROCESSED) == 0) { 1207 if (cc->cc_exec_next_dir == c) 1208 cc->cc_exec_next_dir = LIST_NEXT(c, c_links.le); 1209 LIST_REMOVE(c, c_links.le); 1210 } else 1211 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1212 callout_cc_del(c, cc); 1213 1214 CC_UNLOCK(cc); 1215 return (1); 1216 } 1217 1218 void 1219 callout_init(c, mpsafe) 1220 struct callout *c; 1221 int mpsafe; 1222 { 1223 bzero(c, sizeof *c); 1224 if (mpsafe) { 1225 c->c_lock = NULL; 1226 c->c_flags = CALLOUT_RETURNUNLOCKED; 1227 } else { 1228 c->c_lock = &Giant.lock_object; 1229 c->c_flags = 0; 1230 } 1231 c->c_cpu = timeout_cpu; 1232 } 1233 1234 void 1235 _callout_init_lock(c, lock, flags) 1236 struct callout *c; 1237 struct lock_object *lock; 1238 int flags; 1239 { 1240 bzero(c, sizeof *c); 1241 c->c_lock = lock; 1242 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1243 ("callout_init_lock: bad flags %d", flags)); 1244 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1245 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1246 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & 1247 (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class", 1248 __func__)); 1249 c->c_flags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1250 c->c_cpu = timeout_cpu; 1251 } 1252 1253 #ifdef APM_FIXUP_CALLTODO 1254 /* 1255 * Adjust the kernel calltodo timeout list. This routine is used after 1256 * an APM resume to recalculate the calltodo timer list values with the 1257 * number of hz's we have been sleeping. The next hardclock() will detect 1258 * that there are fired timers and run softclock() to execute them. 1259 * 1260 * Please note, I have not done an exhaustive analysis of what code this 1261 * might break. I am motivated to have my select()'s and alarm()'s that 1262 * have expired during suspend firing upon resume so that the applications 1263 * which set the timer can do the maintanence the timer was for as close 1264 * as possible to the originally intended time. Testing this code for a 1265 * week showed that resuming from a suspend resulted in 22 to 25 timers 1266 * firing, which seemed independant on whether the suspend was 2 hours or 1267 * 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu> 1268 */ 1269 void 1270 adjust_timeout_calltodo(time_change) 1271 struct timeval *time_change; 1272 { 1273 register struct callout *p; 1274 unsigned long delta_ticks; 1275 1276 /* 1277 * How many ticks were we asleep? 1278 * (stolen from tvtohz()). 1279 */ 1280 1281 /* Don't do anything */ 1282 if (time_change->tv_sec < 0) 1283 return; 1284 else if (time_change->tv_sec <= LONG_MAX / 1000000) 1285 delta_ticks = (time_change->tv_sec * 1000000 + 1286 time_change->tv_usec + (tick - 1)) / tick + 1; 1287 else if (time_change->tv_sec <= LONG_MAX / hz) 1288 delta_ticks = time_change->tv_sec * hz + 1289 (time_change->tv_usec + (tick - 1)) / tick + 1; 1290 else 1291 delta_ticks = LONG_MAX; 1292 1293 if (delta_ticks > INT_MAX) 1294 delta_ticks = INT_MAX; 1295 1296 /* 1297 * Now rip through the timer calltodo list looking for timers 1298 * to expire. 1299 */ 1300 1301 /* don't collide with softclock() */ 1302 CC_LOCK(cc); 1303 for (p = calltodo.c_next; p != NULL; p = p->c_next) { 1304 p->c_time -= delta_ticks; 1305 1306 /* Break if the timer had more time on it than delta_ticks */ 1307 if (p->c_time > 0) 1308 break; 1309 1310 /* take back the ticks the timer didn't use (p->c_time <= 0) */ 1311 delta_ticks = -p->c_time; 1312 } 1313 CC_UNLOCK(cc); 1314 1315 return; 1316 } 1317 #endif /* APM_FIXUP_CALLTODO */ 1318 1319 static int 1320 flssbt(sbintime_t sbt) 1321 { 1322 1323 sbt += (uint64_t)sbt >> 1; 1324 if (sizeof(long) >= sizeof(sbintime_t)) 1325 return (flsl(sbt)); 1326 if (sbt >= SBT_1S) 1327 return (flsl(((uint64_t)sbt) >> 32) + 32); 1328 return (flsl(sbt)); 1329 } 1330 1331 /* 1332 * Dump immediate statistic snapshot of the scheduled callouts. 1333 */ 1334 static int 1335 sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1336 { 1337 struct callout *tmp; 1338 struct callout_cpu *cc; 1339 struct callout_list *sc; 1340 sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t; 1341 int ct[64], cpr[64], ccpbk[32]; 1342 int error, val, i, count, tcum, pcum, maxc, c, medc; 1343 #ifdef SMP 1344 int cpu; 1345 #endif 1346 1347 val = 0; 1348 error = sysctl_handle_int(oidp, &val, 0, req); 1349 if (error != 0 || req->newptr == NULL) 1350 return (error); 1351 count = maxc = 0; 1352 st = spr = maxt = maxpr = 0; 1353 bzero(ccpbk, sizeof(ccpbk)); 1354 bzero(ct, sizeof(ct)); 1355 bzero(cpr, sizeof(cpr)); 1356 now = sbinuptime(); 1357 #ifdef SMP 1358 CPU_FOREACH(cpu) { 1359 cc = CC_CPU(cpu); 1360 #else 1361 cc = CC_CPU(timeout_cpu); 1362 #endif 1363 CC_LOCK(cc); 1364 for (i = 0; i < callwheelsize; i++) { 1365 sc = &cc->cc_callwheel[i]; 1366 c = 0; 1367 LIST_FOREACH(tmp, sc, c_links.le) { 1368 c++; 1369 t = tmp->c_time - now; 1370 if (t < 0) 1371 t = 0; 1372 st += t / SBT_1US; 1373 spr += tmp->c_precision / SBT_1US; 1374 if (t > maxt) 1375 maxt = t; 1376 if (tmp->c_precision > maxpr) 1377 maxpr = tmp->c_precision; 1378 ct[flssbt(t)]++; 1379 cpr[flssbt(tmp->c_precision)]++; 1380 } 1381 if (c > maxc) 1382 maxc = c; 1383 ccpbk[fls(c + c / 2)]++; 1384 count += c; 1385 } 1386 CC_UNLOCK(cc); 1387 #ifdef SMP 1388 } 1389 #endif 1390 1391 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1392 tcum += ct[i]; 1393 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1394 for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++) 1395 pcum += cpr[i]; 1396 medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1397 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1398 c += ccpbk[i]; 1399 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1400 1401 printf("Scheduled callouts statistic snapshot:\n"); 1402 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1403 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1404 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1405 medc, 1406 count / callwheelsize / mp_ncpus, 1407 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1408 maxc); 1409 printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1410 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1411 (st / count) / 1000000, (st / count) % 1000000, 1412 maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32); 1413 printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n", 1414 medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32, 1415 (spr / count) / 1000000, (spr / count) % 1000000, 1416 maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32); 1417 printf(" Distribution: \tbuckets\t time\t tcum\t" 1418 " prec\t pcum\n"); 1419 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1420 if (ct[i] == 0 && cpr[i] == 0) 1421 continue; 1422 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1423 tcum += ct[i]; 1424 pcum += cpr[i]; 1425 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n", 1426 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1427 i - 1 - (32 - CC_HASH_SHIFT), 1428 ct[i], tcum, cpr[i], pcum); 1429 } 1430 return (error); 1431 } 1432 SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1433 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1434 0, 0, sysctl_kern_callout_stat, "I", 1435 "Dump immediate statistic snapshot of the scheduled callouts"); 1436