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 * Copyright (c) 2010 Kip Macy. All rights reserved. 11 * Copyright (c) 2013 Patrick Kelsey. All rights reserved. 12 * Copyright (C) 2017-2021 THL A29 Limited, a Tencent company. 13 * All rights reserved. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 40 * 41 * Derived in part from libplebnet's pn_kern_timeout.c and libuinet's uinet_timecounter.c. 42 * 43 */ 44 45 #include <sys/cdefs.h> 46 __FBSDID("$FreeBSD$"); 47 48 #include "opt_callout_profiling.h" 49 #include "opt_ddb.h" 50 #if defined(__arm__) 51 #include "opt_timer.h" 52 #endif 53 #include "opt_rss.h" 54 55 #include <sys/param.h> 56 #include <sys/systm.h> 57 #include <sys/bus.h> 58 #include <sys/callout.h> 59 #include <sys/file.h> 60 #include <sys/interrupt.h> 61 #include <sys/kernel.h> 62 #include <sys/ktr.h> 63 #include <sys/lock.h> 64 #include <sys/malloc.h> 65 #include <sys/mutex.h> 66 #include <sys/proc.h> 67 #include <sys/sdt.h> 68 #include <sys/sleepqueue.h> 69 #include <sys/sysctl.h> 70 #include <sys/smp.h> 71 #include <sys/timetc.h> 72 73 SDT_PROVIDER_DEFINE(callout_execute); 74 SDT_PROBE_DEFINE1(callout_execute, , , callout__start, "struct callout *"); 75 SDT_PROBE_DEFINE1(callout_execute, , , callout__end, "struct callout *"); 76 77 #ifdef CALLOUT_PROFILING 78 static int avg_depth; 79 SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0, 80 "Average number of items examined per softclock call. Units = 1/1000"); 81 static int avg_gcalls; 82 SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0, 83 "Average number of Giant callouts made per softclock call. Units = 1/1000"); 84 static int avg_lockcalls; 85 SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0, 86 "Average number of lock callouts made per softclock call. Units = 1/1000"); 87 static int avg_mpcalls; 88 SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0, 89 "Average number of MP callouts made per softclock call. Units = 1/1000"); 90 #endif 91 92 static int ncallout; 93 SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &ncallout, 0, 94 "Number of entries in callwheel and size of timeout() preallocation"); 95 96 #ifdef RSS 97 static int pin_default_swi = 1; 98 static int pin_pcpu_swi = 1; 99 #else 100 static int pin_default_swi = 0; 101 static int pin_pcpu_swi = 0; 102 #endif 103 104 SYSCTL_INT(_kern, OID_AUTO, pin_default_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_default_swi, 105 0, "Pin the default (non-per-cpu) swi (shared with PCPU 0 swi)"); 106 SYSCTL_INT(_kern, OID_AUTO, pin_pcpu_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_pcpu_swi, 107 0, "Pin the per-CPU swis (except PCPU 0, which is also default"); 108 109 #define sleepq_lock(w) do {} while(0) 110 #define sleepq_release(w) do {} while(0) 111 #define sleepq_add(a, b, c, d, e) do {} while(0) 112 #define sleepq_wait(w, p) do {} while(0) 113 114 #define CC_HASH_SHIFT 8 115 116 /* 117 * TODO: 118 * allocate more timeout table slots when table overflows. 119 */ 120 u_int callwheelsize, callwheelmask; 121 122 /* 123 * The callout cpu exec entities represent informations necessary for 124 * describing the state of callouts currently running on the CPU and the ones 125 * necessary for migrating callouts to the new callout cpu. In particular, 126 * the first entry of the array cc_exec_entity holds informations for callout 127 * running in SWI thread context, while the second one holds informations 128 * for callout running directly from hardware interrupt context. 129 * The cached informations are very important for deferring migration when 130 * the migrating callout is already running. 131 */ 132 struct cc_exec { 133 struct callout *cc_curr; 134 void (*cc_drain)(void *); 135 bool cc_cancel; 136 bool cc_waiting; 137 }; 138 139 /* 140 * There is one struct callout_cpu per cpu, holding all relevant 141 * state for the callout processing thread on the individual CPU. 142 */ 143 struct callout_cpu { 144 struct mtx_padalign cc_lock; 145 struct cc_exec cc_exec_entity[2]; 146 struct callout *cc_next; 147 struct callout *cc_callout; 148 struct callout_list *cc_callwheel; 149 struct callout_tailq cc_expireq; 150 struct callout_slist cc_callfree; 151 int cc_softticks; 152 void *cc_cookie; 153 u_int cc_bucket; 154 u_int cc_inited; 155 char cc_ktr_event_name[20]; 156 }; 157 158 #define callout_migrating(c) ((c)->c_iflags & CALLOUT_DFRMIGRATION) 159 160 #define cc_exec_curr(cc, dir) cc->cc_exec_entity[dir].cc_curr 161 #define cc_exec_drain(cc, dir) cc->cc_exec_entity[dir].cc_drain 162 #define cc_exec_next(cc) cc->cc_next 163 #define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel 164 #define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting 165 struct callout_cpu cc_cpu; 166 #define CC_CPU(cpu) &cc_cpu 167 #define CC_SELF() &cc_cpu 168 #define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock) 169 #define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock) 170 #define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED) 171 172 static int timeout_cpu; 173 174 static void callout_cpu_init(struct callout_cpu *cc, int cpu); 175 static void softclock_call_cc(struct callout *c, struct callout_cpu *cc, 176 #ifdef CALLOUT_PROFILING 177 int *mpcalls, int *lockcalls, int *gcalls, 178 #endif 179 int direct); 180 181 static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures"); 182 183 /** 184 * Locked by cc_lock: 185 * cc_curr - If a callout is in progress, it is cc_curr. 186 * If cc_curr is non-NULL, threads waiting in 187 * callout_drain() will be woken up as soon as the 188 * relevant callout completes. 189 * cc_cancel - Changing to 1 with both callout_lock and cc_lock held 190 * guarantees that the current callout will not run. 191 * The softclock() function sets this to 0 before it 192 * drops callout_lock to acquire c_lock, and it calls 193 * the handler only if curr_cancelled is still 0 after 194 * cc_lock is successfully acquired. 195 * cc_waiting - If a thread is waiting in callout_drain(), then 196 * callout_wait is nonzero. Set only when 197 * cc_curr is non-NULL. 198 */ 199 200 /* 201 * Resets the execution entity tied to a specific callout cpu. 202 */ 203 static void 204 cc_cce_cleanup(struct callout_cpu *cc, int direct) 205 { 206 cc_exec_curr(cc, direct) = NULL; 207 cc_exec_cancel(cc, direct) = false; 208 cc_exec_waiting(cc, direct) = false; 209 } 210 211 /* 212 * Checks if migration is requested by a specific callout cpu. 213 */ 214 static int 215 cc_cce_migrating(struct callout_cpu *cc, int direct) 216 { 217 return (0); 218 } 219 220 /* 221 * Kernel low level callwheel initialization 222 * called on cpu0 during kernel startup. 223 */ 224 static void 225 callout_callwheel_init(void *dummy) 226 { 227 struct callout_cpu *cc; 228 229 /* 230 * Calculate the size of the callout wheel and the preallocated 231 * timeout() structures. 232 * XXX: Clip callout to result of previous function of maxusers 233 * maximum 384. This is still huge, but acceptable. 234 */ 235 memset(CC_CPU(0), 0, sizeof(cc_cpu)); 236 ncallout = imin(16 + maxproc + maxfiles, 18508); 237 TUNABLE_INT_FETCH("kern.ncallout", &ncallout); 238 239 /* 240 * Calculate callout wheel size, should be next power of two higher 241 * than 'ncallout'. 242 */ 243 callwheelsize = 1 << fls(ncallout); 244 callwheelmask = callwheelsize - 1; 245 246 /* 247 * Fetch whether we're pinning the swi's or not. 248 */ 249 TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi); 250 TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi); 251 252 /* 253 * Only cpu0 handles timeout(9) and receives a preallocation. 254 * 255 * XXX: Once all timeout(9) consumers are converted this can 256 * be removed. 257 */ 258 timeout_cpu = PCPU_GET(cpuid); 259 cc = CC_CPU(timeout_cpu); 260 cc->cc_callout = malloc(ncallout * sizeof(struct callout), 261 M_CALLOUT, M_WAITOK); 262 callout_cpu_init(cc, timeout_cpu); 263 } 264 SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL); 265 266 /* 267 * Initialize the per-cpu callout structures. 268 */ 269 static void 270 callout_cpu_init(struct callout_cpu *cc, int cpu) 271 { 272 struct callout *c; 273 int i; 274 275 mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE); 276 SLIST_INIT(&cc->cc_callfree); 277 cc->cc_inited = 1; 278 cc->cc_callwheel = malloc(sizeof(struct callout_list) * callwheelsize, 279 M_CALLOUT, M_WAITOK); 280 for (i = 0; i < callwheelsize; i++) 281 LIST_INIT(&cc->cc_callwheel[i]); 282 TAILQ_INIT(&cc->cc_expireq); 283 for (i = 0; i < 2; i++) 284 cc_cce_cleanup(cc, i); 285 snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name), 286 "callwheel cpu %d", cpu); 287 if (cc->cc_callout == NULL) /* Only cpu0 handles timeout(9) */ 288 return; 289 for (i = 0; i < ncallout; i++) { 290 c = &cc->cc_callout[i]; 291 callout_init(c, 0); 292 c->c_iflags = CALLOUT_LOCAL_ALLOC; 293 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 294 } 295 } 296 297 static inline u_int 298 callout_get_bucket(int to_ticks) 299 { 300 return (to_ticks & callwheelmask); 301 } 302 303 void 304 callout_tick(void) 305 { 306 struct callout_cpu *cc; 307 int need_softclock; 308 int bucket; 309 310 /* 311 * Process callouts at a very low cpu priority, so we don't keep the 312 * relatively high clock interrupt priority any longer than necessary. 313 */ 314 need_softclock = 0; 315 cc = CC_SELF(); 316 mtx_lock(&cc->cc_lock); 317 for (; (cc->cc_softticks - ticks) < 0; cc->cc_softticks++) { 318 bucket = cc->cc_softticks & callwheelmask; 319 if (!LIST_EMPTY(&cc->cc_callwheel[bucket])) { 320 need_softclock = 1; 321 break; 322 } 323 } 324 mtx_unlock(&cc->cc_lock); 325 /* 326 * swi_sched acquires the thread lock, so we don't want to call it 327 * with cc_lock held; incorrect locking order. 328 */ 329 if (need_softclock) 330 softclock(cc); 331 } 332 333 static struct callout_cpu * 334 callout_lock(struct callout *c) 335 { 336 struct callout_cpu *cc; 337 int cpu; 338 339 for (;;) { 340 cpu = c->c_cpu; 341 cc = CC_CPU(cpu); 342 CC_LOCK(cc); 343 if (cpu == c->c_cpu) 344 break; 345 CC_UNLOCK(cc); 346 } 347 return (cc); 348 } 349 350 static void 351 callout_cc_add(struct callout *c, struct callout_cpu *cc, 352 int to_ticks, void (*func)(void *), void *arg, int cpu, int flags) 353 { 354 int bucket; 355 356 CC_LOCK_ASSERT(cc); 357 358 c->c_arg = arg; 359 c->c_iflags |= CALLOUT_PENDING; 360 c->c_iflags &= ~CALLOUT_PROCESSED; 361 c->c_flags |= CALLOUT_ACTIVE; 362 if (flags & C_DIRECT_EXEC) 363 c->c_iflags |= CALLOUT_DIRECT; 364 c->c_func = func; 365 c->c_time = ticks + to_ticks; 366 bucket = callout_get_bucket(c->c_time); 367 LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le); 368 if (cc->cc_bucket == bucket) 369 cc_exec_next(cc) = c; 370 } 371 372 static void 373 callout_cc_del(struct callout *c, struct callout_cpu *cc) 374 { 375 376 if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) == 0) 377 return; 378 c->c_func = NULL; 379 SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle); 380 } 381 382 static void 383 softclock_call_cc(struct callout *c, struct callout_cpu *cc, 384 #ifdef CALLOUT_PROFILING 385 int *mpcalls, int *lockcalls, int *gcalls, 386 #endif 387 int direct) 388 { 389 struct rm_priotracker tracker; 390 void (*c_func)(void *); 391 void *c_arg; 392 struct lock_class *class; 393 struct lock_object *c_lock; 394 uintptr_t lock_status; 395 int c_iflags; 396 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 397 sbintime_t sbt1, sbt2; 398 struct timespec ts2; 399 static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */ 400 static timeout_t *lastfunc; 401 #endif 402 403 KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING, 404 ("softclock_call_cc: pend %p %x", c, c->c_iflags)); 405 KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE, 406 ("softclock_call_cc: act %p %x", c, c->c_flags)); 407 class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL; 408 lock_status = 0; 409 if (c->c_flags & CALLOUT_SHAREDLOCK) { 410 if (class == &lock_class_rm) 411 lock_status = (uintptr_t)&tracker; 412 else 413 lock_status = 1; 414 } 415 c_lock = c->c_lock; 416 c_func = c->c_func; 417 c_arg = c->c_arg; 418 c_iflags = c->c_iflags; 419 if (c->c_iflags & CALLOUT_LOCAL_ALLOC) 420 c->c_iflags = CALLOUT_LOCAL_ALLOC; 421 else 422 c->c_iflags &= ~CALLOUT_PENDING; 423 424 cc_exec_curr(cc, direct) = c; 425 cc_exec_cancel(cc, direct) = false; 426 cc_exec_drain(cc, direct) = NULL; 427 CC_UNLOCK(cc); 428 if (c_lock != NULL) { 429 class->lc_lock(c_lock, lock_status); 430 /* 431 * The callout may have been cancelled 432 * while we switched locks. 433 */ 434 if (cc_exec_cancel(cc, direct)) { 435 class->lc_unlock(c_lock); 436 goto skip; 437 } 438 /* The callout cannot be stopped now. */ 439 cc_exec_cancel(cc, direct) = true; 440 if (c_lock == &Giant.lock_object) { 441 #ifdef CALLOUT_PROFILING 442 (*gcalls)++; 443 #endif 444 CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p", 445 c, c_func, c_arg); 446 } else { 447 #ifdef CALLOUT_PROFILING 448 (*lockcalls)++; 449 #endif 450 CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p", 451 c, c_func, c_arg); 452 } 453 } else { 454 #ifdef CALLOUT_PROFILING 455 (*mpcalls)++; 456 #endif 457 CTR3(KTR_CALLOUT, "callout %p func %p arg %p", 458 c, c_func, c_arg); 459 } 460 KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running", 461 "func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct); 462 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 463 sbt1 = sbinuptime(); 464 #endif 465 THREAD_NO_SLEEPING(); 466 SDT_PROBE1(callout_execute, , , callout__start, c); 467 c_func(c_arg); 468 SDT_PROBE1(callout_execute, , , callout__end, c); 469 THREAD_SLEEPING_OK(); 470 #if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING) 471 sbt2 = sbinuptime(); 472 sbt2 -= sbt1; 473 if (sbt2 > maxdt) { 474 if (lastfunc != c_func || sbt2 > maxdt * 2) { 475 ts2 = sbttots(sbt2); 476 printf( 477 "Expensive timeout(9) function: %p(%p) %jd.%09ld s\n", 478 c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec); 479 } 480 maxdt = sbt2; 481 lastfunc = c_func; 482 } 483 #endif 484 KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle"); 485 CTR1(KTR_CALLOUT, "callout %p finished", c); 486 if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0) 487 class->lc_unlock(c_lock); 488 skip: 489 CC_LOCK(cc); 490 KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr")); 491 cc_exec_curr(cc, direct) = NULL; 492 if (cc_exec_drain(cc, direct)) { 493 void (*drain)(void *); 494 495 drain = cc_exec_drain(cc, direct); 496 cc_exec_drain(cc, direct) = NULL; 497 CC_UNLOCK(cc); 498 drain(c_arg); 499 CC_LOCK(cc); 500 } 501 if (cc_exec_waiting(cc, direct)) { 502 /* 503 * There is someone waiting for the 504 * callout to complete. 505 * If the callout was scheduled for 506 * migration just cancel it. 507 */ 508 if (cc_cce_migrating(cc, direct)) { 509 cc_cce_cleanup(cc, direct); 510 511 /* 512 * It should be assert here that the callout is not 513 * destroyed but that is not easy. 514 */ 515 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 516 } 517 cc_exec_waiting(cc, direct) = false; 518 CC_UNLOCK(cc); 519 wakeup(&cc_exec_waiting(cc, direct)); 520 CC_LOCK(cc); 521 } else if (cc_cce_migrating(cc, direct)) { 522 KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0, 523 ("Migrating legacy callout %p", c)); 524 panic("migration should not happen"); 525 } 526 /* 527 * If the current callout is locally allocated (from 528 * timeout(9)) then put it on the freelist. 529 * 530 * Note: we need to check the cached copy of c_iflags because 531 * if it was not local, then it's not safe to deref the 532 * callout pointer. 533 */ 534 KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0 || 535 c->c_iflags == CALLOUT_LOCAL_ALLOC, 536 ("corrupted callout")); 537 if (c_iflags & CALLOUT_LOCAL_ALLOC) 538 callout_cc_del(c, cc); 539 } 540 541 /* 542 * The callout mechanism is based on the work of Adam M. Costello and 543 * George Varghese, published in a technical report entitled "Redesigning 544 * the BSD Callout and Timer Facilities" and modified slightly for inclusion 545 * in FreeBSD by Justin T. Gibbs. The original work on the data structures 546 * used in this implementation was published by G. Varghese and T. Lauck in 547 * the paper "Hashed and Hierarchical Timing Wheels: Data Structures for 548 * the Efficient Implementation of a Timer Facility" in the Proceedings of 549 * the 11th ACM Annual Symposium on Operating Systems Principles, 550 * Austin, Texas Nov 1987. 551 */ 552 553 /* 554 * Software (low priority) clock interrupt. 555 * Run periodic events from timeout queue. 556 */ 557 void 558 softclock(void *arg) 559 { 560 struct callout *c; 561 struct callout_cpu *cc; 562 struct callout_list *sc; 563 int curticks; 564 #ifdef CALLOUT_PROFILING 565 int depth = 0, gcalls = 0, mpcalls = 0, lockcalls = 0; 566 #endif 567 568 cc = (struct callout_cpu *)arg; 569 CC_LOCK(cc); 570 571 while (cc->cc_softticks != ticks) { 572 /* 573 * cc_softticks may be modified by hard clock, so cache 574 * it while we work on a given bucket. 575 */ 576 curticks = cc->cc_softticks; 577 cc->cc_softticks++; 578 sc = &cc->cc_callwheel[curticks & callwheelmask]; 579 c = LIST_FIRST(sc); 580 while (c) { 581 #ifdef CALLOUT_PROFILING 582 depth++; 583 #endif 584 if (c->c_time != curticks) { 585 c = LIST_NEXT(c, c_links.le); 586 } else { 587 cc_exec_next(cc) = 588 LIST_NEXT(c, c_links.le); 589 cc->cc_bucket = callout_get_bucket(curticks); 590 LIST_REMOVE(c, c_links.le); 591 softclock_call_cc(c, cc, 592 #ifdef CALLOUT_PROFILING 593 &mpcalls, &lockcalls, &gcalls, 594 #endif 595 1); 596 c = cc_exec_next(cc); 597 cc_exec_next(cc) = NULL; 598 } 599 } 600 } 601 602 #ifdef CALLOUT_PROFILING 603 avg_depth += (depth * 1000 - avg_depth) >> 8; 604 avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8; 605 avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8; 606 avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8; 607 #endif 608 CC_UNLOCK(cc); 609 } 610 611 #if 0 612 /* 613 * timeout -- 614 * Execute a function after a specified length of time. 615 * 616 * untimeout -- 617 * Cancel previous timeout function call. 618 * 619 * callout_handle_init -- 620 * Initialize a handle so that using it with untimeout is benign. 621 * 622 * See AT&T BCI Driver Reference Manual for specification. This 623 * implementation differs from that one in that although an 624 * identification value is returned from timeout, the original 625 * arguments to timeout as well as the identifier are used to 626 * identify entries for untimeout. 627 */ 628 struct callout_handle 629 timeout(timeout_t *ftn, void *arg, int to_ticks) 630 { 631 struct callout_cpu *cc; 632 struct callout *new; 633 struct callout_handle handle; 634 635 cc = CC_CPU(timeout_cpu); 636 CC_LOCK(cc); 637 /* Fill in the next free callout structure. */ 638 new = SLIST_FIRST(&cc->cc_callfree); 639 if (new == NULL) 640 /* XXX Attempt to malloc first */ 641 panic("timeout table full"); 642 SLIST_REMOVE_HEAD(&cc->cc_callfree, c_links.sle); 643 callout_reset(new, to_ticks, ftn, arg); 644 handle.callout = new; 645 CC_UNLOCK(cc); 646 647 return (handle); 648 } 649 650 void 651 untimeout(timeout_t *ftn, void *arg, struct callout_handle handle) 652 { 653 struct callout_cpu *cc; 654 655 /* 656 * Check for a handle that was initialized 657 * by callout_handle_init, but never used 658 * for a real timeout. 659 */ 660 if (handle.callout == NULL) 661 return; 662 663 cc = callout_lock(handle.callout); 664 if (handle.callout->c_func == ftn && handle.callout->c_arg == arg) 665 callout_stop(handle.callout); 666 CC_UNLOCK(cc); 667 } 668 669 void 670 callout_handle_init(struct callout_handle *handle) 671 { 672 handle->callout = NULL; 673 } 674 #endif 675 676 /* 677 * New interface; clients allocate their own callout structures. 678 * 679 * callout_reset() - establish or change a timeout 680 * callout_stop() - disestablish a timeout 681 * callout_init() - initialize a callout structure so that it can 682 * safely be passed to callout_reset() and callout_stop() 683 * 684 * <sys/callout.h> defines three convenience macros: 685 * 686 * callout_active() - returns truth if callout has not been stopped, 687 * drained, or deactivated since the last time the callout was 688 * reset. 689 * callout_pending() - returns truth if callout is still waiting for timeout 690 * callout_deactivate() - marks the callout as having been serviced 691 */ 692 int 693 callout_reset_tick_on(struct callout *c, int to_ticks, 694 void (*ftn)(void *), void *arg, int cpu, int flags) 695 { 696 struct callout_cpu *cc; 697 int cancelled, direct; 698 int ignore_cpu=0; 699 700 cancelled = 0; 701 if (cpu == -1) { 702 ignore_cpu = 1; 703 } else if ((cpu >= MAXCPU) || 704 ((CC_CPU(cpu))->cc_inited == 0)) { 705 /* Invalid CPU spec */ 706 panic("Invalid CPU in callout %d", cpu); 707 } 708 709 /* 710 * This flag used to be added by callout_cc_add, but the 711 * first time you call this we could end up with the 712 * wrong direct flag if we don't do it before we add. 713 */ 714 if (flags & C_DIRECT_EXEC) { 715 direct = 1; 716 } else { 717 direct = 0; 718 } 719 KASSERT(!direct || c->c_lock == NULL, 720 ("%s: direct callout %p has lock", __func__, c)); 721 cc = callout_lock(c); 722 /* 723 * Don't allow migration of pre-allocated callouts lest they 724 * become unbalanced or handle the case where the user does 725 * not care. 726 */ 727 if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) || 728 ignore_cpu) { 729 cpu = c->c_cpu; 730 } 731 732 if (cc_exec_curr(cc, direct) == c) { 733 /* 734 * We're being asked to reschedule a callout which is 735 * currently in progress. If there is a lock then we 736 * can cancel the callout if it has not really started. 737 */ 738 if (c->c_lock != NULL && !cc_exec_cancel(cc, direct)) 739 cancelled = cc_exec_cancel(cc, direct) = true; 740 if (cc_exec_waiting(cc, direct)) { 741 /* 742 * Someone has called callout_drain to kill this 743 * callout. Don't reschedule. 744 */ 745 CTR4(KTR_CALLOUT, "%s %p func %p arg %p", 746 cancelled ? "cancelled" : "failed to cancel", 747 c, c->c_func, c->c_arg); 748 CC_UNLOCK(cc); 749 return (cancelled); 750 } 751 } 752 if (c->c_iflags & CALLOUT_PENDING) { 753 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 754 if (cc_exec_next(cc) == c) 755 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 756 LIST_REMOVE(c, c_links.le); 757 } else { 758 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 759 } 760 cancelled = 1; 761 c->c_iflags &= ~ CALLOUT_PENDING; 762 c->c_flags &= ~ CALLOUT_ACTIVE; 763 } 764 765 if (to_ticks <= 0) 766 to_ticks = 1; 767 768 callout_cc_add(c, cc, to_ticks, ftn, arg, cpu, flags); 769 CTR5(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d", 770 cancelled ? "re" : "", c, c->c_func, c->c_arg, to_ticks); 771 CC_UNLOCK(cc); 772 773 return (cancelled); 774 } 775 776 /* 777 * Common idioms that can be optimized in the future. 778 */ 779 int 780 callout_schedule_on(struct callout *c, int to_ticks, int cpu) 781 { 782 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu); 783 } 784 785 int 786 callout_schedule(struct callout *c, int to_ticks) 787 { 788 return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu); 789 } 790 791 int 792 _callout_stop_safe(struct callout *c, int flags, void (*drain)(void *)) 793 { 794 struct callout_cpu *cc, *old_cc; 795 struct lock_class *class; 796 int direct, sq_locked, use_lock; 797 int cancelled, not_on_a_list; 798 799 if ((flags & CS_DRAIN) != 0) 800 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock, 801 "calling %s", __func__); 802 803 /* 804 * Some old subsystems don't hold Giant while running a callout_stop(), 805 * so just discard this check for the moment. 806 */ 807 if ((flags & CS_DRAIN) == 0 && c->c_lock != NULL) { 808 if (c->c_lock == &Giant.lock_object) 809 use_lock = mtx_owned(&Giant); 810 else { 811 use_lock = 1; 812 class = LOCK_CLASS(c->c_lock); 813 class->lc_assert(c->c_lock, LA_XLOCKED); 814 } 815 } else 816 use_lock = 0; 817 if (c->c_iflags & CALLOUT_DIRECT) { 818 direct = 1; 819 } else { 820 direct = 0; 821 } 822 sq_locked = 0; 823 old_cc = NULL; 824 again: 825 cc = callout_lock(c); 826 827 if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) == 828 (CALLOUT_DFRMIGRATION | CALLOUT_PENDING) && 829 ((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) { 830 /* 831 * Special case where this slipped in while we 832 * were migrating *as* the callout is about to 833 * execute. The caller probably holds the lock 834 * the callout wants. 835 * 836 * Get rid of the migration first. Then set 837 * the flag that tells this code *not* to 838 * try to remove it from any lists (its not 839 * on one yet). When the callout wheel runs, 840 * it will ignore this callout. 841 */ 842 c->c_iflags &= ~CALLOUT_PENDING; 843 c->c_flags &= ~CALLOUT_ACTIVE; 844 not_on_a_list = 1; 845 } else { 846 not_on_a_list = 0; 847 } 848 849 /* 850 * If the callout was migrating while the callout cpu lock was 851 * dropped, just drop the sleepqueue lock and check the states 852 * again. 853 */ 854 if (sq_locked != 0 && cc != old_cc) { 855 panic("migration should not happen"); 856 } 857 858 /* 859 * If the callout is running, try to stop it or drain it. 860 */ 861 if (cc_exec_curr(cc, direct) == c) { 862 /* 863 * Succeed we to stop it or not, we must clear the 864 * active flag - this is what API users expect. 865 */ 866 c->c_flags &= ~CALLOUT_ACTIVE; 867 868 if ((flags & CS_DRAIN) != 0) { 869 /* 870 * The current callout is running (or just 871 * about to run) and blocking is allowed, so 872 * just wait for the current invocation to 873 * finish. 874 */ 875 while (cc_exec_curr(cc, direct) == c) { 876 /* 877 * Use direct calls to sleepqueue interface 878 * instead of cv/msleep in order to avoid 879 * a LOR between cc_lock and sleepqueue 880 * chain spinlocks. This piece of code 881 * emulates a msleep_spin() call actually. 882 * 883 * If we already have the sleepqueue chain 884 * locked, then we can safely block. If we 885 * don't already have it locked, however, 886 * we have to drop the cc_lock to lock 887 * it. This opens several races, so we 888 * restart at the beginning once we have 889 * both locks. If nothing has changed, then 890 * we will end up back here with sq_locked 891 * set. 892 */ 893 if (!sq_locked) { 894 CC_UNLOCK(cc); 895 sleepq_lock( 896 &cc_exec_waiting(cc, direct)); 897 sq_locked = 1; 898 old_cc = cc; 899 goto again; 900 } 901 902 /* 903 * Migration could be cancelled here, but 904 * as long as it is still not sure when it 905 * will be packed up, just let softclock() 906 * take care of it. 907 */ 908 cc_exec_waiting(cc, direct) = true; 909 DROP_GIANT(); 910 CC_UNLOCK(cc); 911 sleepq_add( 912 &cc_exec_waiting(cc, direct), 913 &cc->cc_lock.lock_object, "codrain", 914 SLEEPQ_SLEEP, 0); 915 sleepq_wait( 916 &cc_exec_waiting(cc, direct), 917 0); 918 sq_locked = 0; 919 old_cc = NULL; 920 921 /* Reacquire locks previously released. */ 922 PICKUP_GIANT(); 923 CC_LOCK(cc); 924 } 925 } else if (use_lock && 926 !cc_exec_cancel(cc, direct) && (drain == NULL)) { 927 928 /* 929 * The current callout is waiting for its 930 * lock which we hold. Cancel the callout 931 * and return. After our caller drops the 932 * lock, the callout will be skipped in 933 * softclock(). This *only* works with a 934 * callout_stop() *not* callout_drain() or 935 * callout_async_drain(). 936 */ 937 cc_exec_cancel(cc, direct) = true; 938 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 939 c, c->c_func, c->c_arg); 940 KASSERT(!cc_cce_migrating(cc, direct), 941 ("callout wrongly scheduled for migration")); 942 if (callout_migrating(c)) { 943 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 944 } 945 CC_UNLOCK(cc); 946 KASSERT(!sq_locked, ("sleepqueue chain locked")); 947 return (1); 948 } else if (callout_migrating(c)) { 949 /* 950 * The callout is currently being serviced 951 * and the "next" callout is scheduled at 952 * its completion with a migration. We remove 953 * the migration flag so it *won't* get rescheduled, 954 * but we can't stop the one thats running so 955 * we return 0. 956 */ 957 c->c_iflags &= ~CALLOUT_DFRMIGRATION; 958 CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p", 959 c, c->c_func, c->c_arg); 960 if (drain) { 961 cc_exec_drain(cc, direct) = drain; 962 } 963 CC_UNLOCK(cc); 964 return ((flags & CS_EXECUTING) != 0); 965 } 966 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 967 c, c->c_func, c->c_arg); 968 if (drain) { 969 cc_exec_drain(cc, direct) = drain; 970 } 971 KASSERT(!sq_locked, ("sleepqueue chain still locked")); 972 cancelled = ((flags & CS_EXECUTING) != 0); 973 } else 974 cancelled = 1; 975 976 if (sq_locked) 977 sleepq_release(&cc_exec_waiting(cc, direct)); 978 979 if ((c->c_iflags & CALLOUT_PENDING) == 0) { 980 CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p", 981 c, c->c_func, c->c_arg); 982 /* 983 * For not scheduled and not executing callout return 984 * negative value. 985 */ 986 if (cc_exec_curr(cc, direct) != c) 987 cancelled = -1; 988 CC_UNLOCK(cc); 989 return (cancelled); 990 } 991 992 c->c_iflags &= ~CALLOUT_PENDING; 993 c->c_flags &= ~CALLOUT_ACTIVE; 994 995 CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p", 996 c, c->c_func, c->c_arg); 997 if (not_on_a_list == 0) { 998 if ((c->c_iflags & CALLOUT_PROCESSED) == 0) { 999 if (cc_exec_next(cc) == c) 1000 cc_exec_next(cc) = LIST_NEXT(c, c_links.le); 1001 LIST_REMOVE(c, c_links.le); 1002 } else { 1003 TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe); 1004 } 1005 } 1006 callout_cc_del(c, cc); 1007 CC_UNLOCK(cc); 1008 return (cancelled); 1009 } 1010 1011 void 1012 callout_init(struct callout *c, int mpsafe) 1013 { 1014 bzero(c, sizeof *c); 1015 if (mpsafe) { 1016 c->c_lock = NULL; 1017 c->c_iflags = CALLOUT_RETURNUNLOCKED; 1018 } else { 1019 c->c_lock = &Giant.lock_object; 1020 c->c_iflags = 0; 1021 } 1022 c->c_cpu = timeout_cpu; 1023 } 1024 1025 void 1026 _callout_init_lock(struct callout *c, struct lock_object *lock, int flags) 1027 { 1028 bzero(c, sizeof *c); 1029 c->c_lock = lock; 1030 KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0, 1031 ("callout_init_lock: bad flags %d", flags)); 1032 KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0, 1033 ("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock")); 1034 KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags & 1035 (LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class", 1036 __func__)); 1037 c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK); 1038 c->c_cpu = timeout_cpu; 1039 } 1040 1041 #ifdef APM_FIXUP_CALLTODO 1042 /* 1043 * Adjust the kernel calltodo timeout list. This routine is used after 1044 * an APM resume to recalculate the calltodo timer list values with the 1045 * number of hz's we have been sleeping. The next hardclock() will detect 1046 * that there are fired timers and run softclock() to execute them. 1047 * 1048 * Please note, I have not done an exhaustive analysis of what code this 1049 * might break. I am motivated to have my select()'s and alarm()'s that 1050 * have expired during suspend firing upon resume so that the applications 1051 * which set the timer can do the maintanence the timer was for as close 1052 * as possible to the originally intended time. Testing this code for a 1053 * week showed that resuming from a suspend resulted in 22 to 25 timers 1054 * firing, which seemed independent on whether the suspend was 2 hours or 1055 * 2 days. Your milage may vary. - Ken Key <[email protected]> 1056 */ 1057 void 1058 adjust_timeout_calltodo(struct timeval *time_change) 1059 { 1060 register struct callout *p; 1061 unsigned long delta_ticks; 1062 1063 /* 1064 * How many ticks were we asleep? 1065 * (stolen from tvtohz()). 1066 */ 1067 1068 /* Don't do anything */ 1069 if (time_change->tv_sec < 0) 1070 return; 1071 else if (time_change->tv_sec <= LONG_MAX / 1000000) 1072 delta_ticks = howmany(time_change->tv_sec * 1000000 + 1073 time_change->tv_usec, tick) + 1; 1074 else if (time_change->tv_sec <= LONG_MAX / hz) 1075 delta_ticks = time_change->tv_sec * hz + 1076 howmany(time_change->tv_usec, tick) + 1; 1077 else 1078 delta_ticks = LONG_MAX; 1079 1080 if (delta_ticks > INT_MAX) 1081 delta_ticks = INT_MAX; 1082 1083 /* 1084 * Now rip through the timer calltodo list looking for timers 1085 * to expire. 1086 */ 1087 1088 /* don't collide with softclock() */ 1089 CC_LOCK(cc); 1090 for (p = calltodo.c_next; p != NULL; p = p->c_next) { 1091 p->c_time -= delta_ticks; 1092 1093 /* Break if the timer had more time on it than delta_ticks */ 1094 if (p->c_time > 0) 1095 break; 1096 1097 /* take back the ticks the timer didn't use (p->c_time <= 0) */ 1098 delta_ticks = -p->c_time; 1099 } 1100 CC_UNLOCK(cc); 1101 1102 return; 1103 } 1104 #endif /* APM_FIXUP_CALLTODO */ 1105 1106 static int 1107 flssbt(sbintime_t sbt) 1108 { 1109 1110 sbt += (uint64_t)sbt >> 1; 1111 if (sizeof(long) >= sizeof(sbintime_t)) 1112 return (flsl(sbt)); 1113 if (sbt >= SBT_1S) 1114 return (flsl(((uint64_t)sbt) >> 32) + 32); 1115 return (flsl(sbt)); 1116 } 1117 1118 /* 1119 * Dump immediate statistic snapshot of the scheduled callouts. 1120 */ 1121 static int 1122 sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS) 1123 { 1124 struct callout *tmp; 1125 struct callout_cpu *cc; 1126 struct callout_list *sc; 1127 int st, maxt, tick, now; 1128 sbintime_t medt; 1129 int ct[64], ccpbk[32]; 1130 int error, val, i, count, tcum, pcum, maxc, c, medc; 1131 1132 val = 0; 1133 error = sysctl_handle_int(oidp, &val, 0, req); 1134 if (error != 0 || req->newptr == NULL) 1135 return (error); 1136 count = maxc = 0; 1137 st = maxt = 0; 1138 bzero(ccpbk, sizeof(ccpbk)); 1139 bzero(ct, sizeof(ct)); 1140 now = ticks; 1141 1142 cc = CC_CPU(timeout_cpu); 1143 CC_LOCK(cc); 1144 for (i = 0; i < callwheelsize; i++) { 1145 sc = &cc->cc_callwheel[i]; 1146 c = 0; 1147 LIST_FOREACH(tmp, sc, c_links.le) { 1148 c++; 1149 tick = tmp->c_time - now; 1150 if (tick < 0) 1151 tick = 0; 1152 st += tick*(1000/hz); 1153 if (tick > maxt) 1154 maxt = tick; 1155 ct[flssbt(tick)]++; 1156 } 1157 if (c > maxc) 1158 maxc = c; 1159 ccpbk[fls(c + c / 2)]++; 1160 count += c; 1161 } 1162 CC_UNLOCK(cc); 1163 1164 for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++) 1165 tcum += ct[i]; 1166 medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0; 1167 for (i = 0, c = 0; i < 32 && c < count / 2; i++) 1168 c += ccpbk[i]; 1169 medc = (i >= 2) ? (1 << (i - 2)) : 0; 1170 1171 printf("Scheduled callouts statistic snapshot:\n"); 1172 printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n", 1173 count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT); 1174 printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n", 1175 medc, 1176 count / callwheelsize / mp_ncpus, 1177 (uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000, 1178 maxc); 1179 printf(" Time: med %5jd.%06jds avg %6d.%06ds max %ds\n", 1180 medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32, 1181 st / count / 1000, (st / count) % 1000, maxt); 1182 printf(" Distribution: \tbuckets\t time\t tcum\n"); 1183 for (i = 0, tcum = pcum = 0; i < 64; i++) { 1184 if (ct[i] == 0) 1185 continue; 1186 sbintime_t t; 1187 t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0; 1188 tcum += ct[i]; 1189 printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\n", 1190 t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32, 1191 i - 1 - (32 - CC_HASH_SHIFT), ct[i], tcum); 1192 } 1193 return (error); 1194 } 1195 SYSCTL_PROC(_kern, OID_AUTO, callout_stat, 1196 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 1197 0, 0, sysctl_kern_callout_stat, "I", 1198 "Dump immediate statistic snapshot of the scheduled callouts"); 1199 1200 #ifdef FSTACK 1201 void ff_hardclock(void); 1202 1203 void 1204 ff_hardclock(void) 1205 { 1206 atomic_add_int(&ticks, 1); 1207 callout_tick(); 1208 tc_ticktock(1); 1209 cpu_tick_calibration(); 1210 1211 #ifdef DEVICE_POLLING 1212 hardclock_device_poll(); /* this is very short and quick */ 1213 #endif /* DEVICE_POLLING */ 1214 } 1215 1216 static unsigned int 1217 ff_tc_get_timecount(struct timecounter *tc) 1218 { 1219 uint64_t ns; 1220 ns = ff_get_tsc_ns(); 1221 return ((ns * tc->tc_frequency) / ff_NSEC_PER_SEC); 1222 } 1223 1224 static struct timecounter ff_timecounter = { 1225 ff_tc_get_timecount, 0, ~0u, 100, "ff_clock", 1 1226 }; 1227 1228 static void 1229 ff_tc_init(void) 1230 { 1231 ff_timecounter.tc_frequency = hz; 1232 tc_init(&ff_timecounter); 1233 } 1234 SYSINIT(ff_tc, SI_SUB_SMP, SI_ORDER_ANY, ff_tc_init, NULL); 1235 #endif 1236