kern_mutex.c revision 167365
1/*- 2 * Copyright (c) 1998 Berkeley Software Design, Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. Berkeley Software Design Inc's name may not be used to endorse or 13 * promote products derived from this software without specific prior 14 * written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * from BSDI $Id: mutex_witness.c,v 1.1.2.20 2000/04/27 03:10:27 cp Exp $ 29 * and BSDI $Id: synch_machdep.c,v 2.3.2.39 2000/04/27 03:10:25 cp Exp $ 30 */ 31 32/* 33 * Machine independent bits of mutex implementation. 34 */ 35 36#include <sys/cdefs.h> 37__FBSDID("$FreeBSD: head/sys/kern/kern_mutex.c 167365 2007-03-09 16:04:44Z jhb $"); 38 39#include "opt_adaptive_mutexes.h" 40#include "opt_ddb.h" 41#include "opt_global.h" 42#include "opt_mutex_wake_all.h" 43#include "opt_sched.h" 44 45#include <sys/param.h> 46#include <sys/systm.h> 47#include <sys/bus.h> 48#include <sys/conf.h> 49#include <sys/kdb.h> 50#include <sys/kernel.h> 51#include <sys/ktr.h> 52#include <sys/lock.h> 53#include <sys/malloc.h> 54#include <sys/mutex.h> 55#include <sys/proc.h> 56#include <sys/resourcevar.h> 57#include <sys/sched.h> 58#include <sys/sbuf.h> 59#include <sys/sysctl.h> 60#include <sys/turnstile.h> 61#include <sys/vmmeter.h> 62#include <sys/lock_profile.h> 63 64#include <machine/atomic.h> 65#include <machine/bus.h> 66#include <machine/cpu.h> 67 68#include <ddb/ddb.h> 69 70#include <fs/devfs/devfs_int.h> 71 72#include <vm/vm.h> 73#include <vm/vm_extern.h> 74 75/* 76 * Force MUTEX_WAKE_ALL for now. 77 * single thread wakeup needs fixes to avoid race conditions with 78 * priority inheritance. 79 */ 80#ifndef MUTEX_WAKE_ALL 81#define MUTEX_WAKE_ALL 82#endif 83 84/* 85 * Internal utility macros. 86 */ 87#define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED) 88 89#define mtx_owner(m) ((struct thread *)((m)->mtx_lock & ~MTX_FLAGMASK)) 90 91#ifdef DDB 92static void db_show_mtx(struct lock_object *lock); 93#endif 94 95/* 96 * Lock classes for sleep and spin mutexes. 97 */ 98struct lock_class lock_class_mtx_sleep = { 99 .lc_name = "sleep mutex", 100 .lc_flags = LC_SLEEPLOCK | LC_RECURSABLE, 101#ifdef DDB 102 .lc_ddb_show = db_show_mtx, 103#endif 104}; 105struct lock_class lock_class_mtx_spin = { 106 .lc_name = "spin mutex", 107 .lc_flags = LC_SPINLOCK | LC_RECURSABLE, 108#ifdef DDB 109 .lc_ddb_show = db_show_mtx, 110#endif 111}; 112 113/* 114 * System-wide mutexes 115 */ 116struct mtx sched_lock; 117struct mtx Giant; 118 119#ifdef LOCK_PROFILING 120static inline void lock_profile_init(void) 121{ 122 int i; 123 /* Initialize the mutex profiling locks */ 124 for (i = 0; i < LPROF_LOCK_SIZE; i++) { 125 mtx_init(&lprof_locks[i], "mprof lock", 126 NULL, MTX_SPIN|MTX_QUIET|MTX_NOPROFILE); 127 } 128} 129#else 130static inline void lock_profile_init(void) {;} 131#endif 132 133/* 134 * Function versions of the inlined __mtx_* macros. These are used by 135 * modules and can also be called from assembly language if needed. 136 */ 137void 138_mtx_lock_flags(struct mtx *m, int opts, const char *file, int line) 139{ 140 141 MPASS(curthread != NULL); 142 KASSERT(m->mtx_lock != MTX_DESTROYED, 143 ("mtx_lock() of destroyed mutex @ %s:%d", file, line)); 144 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_sleep, 145 ("mtx_lock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name, 146 file, line)); 147 WITNESS_CHECKORDER(&m->mtx_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE, 148 file, line); 149 150 _get_sleep_lock(m, curthread, opts, file, line); 151 LOCK_LOG_LOCK("LOCK", &m->mtx_object, opts, m->mtx_recurse, file, 152 line); 153 WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line); 154 curthread->td_locks++; 155} 156 157void 158_mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line) 159{ 160 MPASS(curthread != NULL); 161 KASSERT(m->mtx_lock != MTX_DESTROYED, 162 ("mtx_unlock() of destroyed mutex @ %s:%d", file, line)); 163 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_sleep, 164 ("mtx_unlock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name, 165 file, line)); 166 curthread->td_locks--; 167 WITNESS_UNLOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line); 168 LOCK_LOG_LOCK("UNLOCK", &m->mtx_object, opts, m->mtx_recurse, file, 169 line); 170 mtx_assert(m, MA_OWNED); 171 172 lock_profile_release_lock(&m->mtx_object); 173 _rel_sleep_lock(m, curthread, opts, file, line); 174} 175 176void 177_mtx_lock_spin_flags(struct mtx *m, int opts, const char *file, int line) 178{ 179 180 MPASS(curthread != NULL); 181 KASSERT(m->mtx_lock != MTX_DESTROYED, 182 ("mtx_lock_spin() of destroyed mutex @ %s:%d", file, line)); 183 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_spin, 184 ("mtx_lock_spin() of sleep mutex %s @ %s:%d", 185 m->mtx_object.lo_name, file, line)); 186 WITNESS_CHECKORDER(&m->mtx_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE, 187 file, line); 188 _get_spin_lock(m, curthread, opts, file, line); 189 LOCK_LOG_LOCK("LOCK", &m->mtx_object, opts, m->mtx_recurse, file, 190 line); 191 WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line); 192} 193 194void 195_mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file, int line) 196{ 197 198 MPASS(curthread != NULL); 199 KASSERT(m->mtx_lock != MTX_DESTROYED, 200 ("mtx_unlock_spin() of destroyed mutex @ %s:%d", file, line)); 201 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_spin, 202 ("mtx_unlock_spin() of sleep mutex %s @ %s:%d", 203 m->mtx_object.lo_name, file, line)); 204 WITNESS_UNLOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line); 205 LOCK_LOG_LOCK("UNLOCK", &m->mtx_object, opts, m->mtx_recurse, file, 206 line); 207 mtx_assert(m, MA_OWNED); 208 209 lock_profile_release_lock(&m->mtx_object); 210 _rel_spin_lock(m); 211} 212 213/* 214 * The important part of mtx_trylock{,_flags}() 215 * Tries to acquire lock `m.' If this function is called on a mutex that 216 * is already owned, it will recursively acquire the lock. 217 */ 218int 219_mtx_trylock(struct mtx *m, int opts, const char *file, int line) 220{ 221 int rval, contested = 0; 222 uint64_t waittime = 0; 223 224 MPASS(curthread != NULL); 225 KASSERT(m->mtx_lock != MTX_DESTROYED, 226 ("mtx_trylock() of destroyed mutex @ %s:%d", file, line)); 227 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_sleep, 228 ("mtx_trylock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name, 229 file, line)); 230 231 if (mtx_owned(m) && (m->mtx_object.lo_flags & LO_RECURSABLE) != 0) { 232 m->mtx_recurse++; 233 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); 234 rval = 1; 235 } else 236 rval = _obtain_lock(m, (uintptr_t)curthread); 237 238 LOCK_LOG_TRY("LOCK", &m->mtx_object, opts, rval, file, line); 239 if (rval) { 240 WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK, 241 file, line); 242 curthread->td_locks++; 243 if (m->mtx_recurse == 0) 244 lock_profile_obtain_lock_success(&m->mtx_object, contested, 245 waittime, file, line); 246 247 } 248 249 return (rval); 250} 251 252/* 253 * _mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock. 254 * 255 * We call this if the lock is either contested (i.e. we need to go to 256 * sleep waiting for it), or if we need to recurse on it. 257 */ 258void 259_mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts, const char *file, 260 int line) 261{ 262#if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES) 263 volatile struct thread *owner; 264#endif 265#ifdef KTR 266 int cont_logged = 0; 267#endif 268 uintptr_t v; 269 270 if (mtx_owned(m)) { 271 KASSERT((m->mtx_object.lo_flags & LO_RECURSABLE) != 0, 272 ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n", 273 m->mtx_object.lo_name, file, line)); 274 m->mtx_recurse++; 275 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); 276 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 277 CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m); 278 return; 279 } 280 281 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 282 CTR4(KTR_LOCK, 283 "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d", 284 m->mtx_object.lo_name, (void *)m->mtx_lock, file, line); 285 286 while (!_obtain_lock(m, tid)) { 287 turnstile_lock(&m->mtx_object); 288 v = m->mtx_lock; 289 290 /* 291 * Check if the lock has been released while spinning for 292 * the turnstile chain lock. 293 */ 294 if (v == MTX_UNOWNED) { 295 turnstile_release(&m->mtx_object); 296 cpu_spinwait(); 297 continue; 298 } 299 300#ifdef MUTEX_WAKE_ALL 301 MPASS(v != MTX_CONTESTED); 302#else 303 /* 304 * The mutex was marked contested on release. This means that 305 * there are other threads blocked on it. Grab ownership of 306 * it and propagate its priority to the current thread if 307 * necessary. 308 */ 309 if (v == MTX_CONTESTED) { 310 m->mtx_lock = tid | MTX_CONTESTED; 311 turnstile_claim(&m->mtx_object); 312 break; 313 } 314#endif 315 316 /* 317 * If the mutex isn't already contested and a failure occurs 318 * setting the contested bit, the mutex was either released 319 * or the state of the MTX_RECURSED bit changed. 320 */ 321 if ((v & MTX_CONTESTED) == 0 && 322 !atomic_cmpset_ptr(&m->mtx_lock, v, v | MTX_CONTESTED)) { 323 turnstile_release(&m->mtx_object); 324 cpu_spinwait(); 325 continue; 326 } 327 328#if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES) 329 /* 330 * If the current owner of the lock is executing on another 331 * CPU, spin instead of blocking. 332 */ 333 owner = (struct thread *)(v & ~MTX_FLAGMASK); 334#ifdef ADAPTIVE_GIANT 335 if (TD_IS_RUNNING(owner)) 336#else 337 if (m != &Giant && TD_IS_RUNNING(owner)) 338#endif 339 { 340 turnstile_release(&m->mtx_object); 341 while (mtx_owner(m) == owner && TD_IS_RUNNING(owner)) { 342 cpu_spinwait(); 343 } 344 continue; 345 } 346#endif /* SMP && !NO_ADAPTIVE_MUTEXES */ 347 348 /* 349 * We definitely must sleep for this lock. 350 */ 351 mtx_assert(m, MA_NOTOWNED); 352 353#ifdef KTR 354 if (!cont_logged) { 355 CTR6(KTR_CONTENTION, 356 "contention: %p at %s:%d wants %s, taken by %s:%d", 357 (void *)tid, file, line, m->mtx_object.lo_name, 358 WITNESS_FILE(&m->mtx_object), 359 WITNESS_LINE(&m->mtx_object)); 360 cont_logged = 1; 361 } 362#endif 363 364 /* 365 * Block on the turnstile. 366 */ 367 turnstile_wait(&m->mtx_object, mtx_owner(m), 368 TS_EXCLUSIVE_QUEUE); 369 } 370#ifdef KTR 371 if (cont_logged) { 372 CTR4(KTR_CONTENTION, 373 "contention end: %s acquired by %p at %s:%d", 374 m->mtx_object.lo_name, (void *)tid, file, line); 375 } 376#endif 377 return; 378} 379 380#ifdef SMP 381/* 382 * _mtx_lock_spin: the tougher part of acquiring an MTX_SPIN lock. 383 * 384 * This is only called if we need to actually spin for the lock. Recursion 385 * is handled inline. 386 */ 387void 388_mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts, const char *file, 389 int line) 390{ 391 int i = 0; 392 struct thread *td; 393 394 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 395 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m); 396 397 while (!_obtain_lock(m, tid)) { 398 399 /* Give interrupts a chance while we spin. */ 400 spinlock_exit(); 401 while (m->mtx_lock != MTX_UNOWNED) { 402 if (i++ < 10000000) { 403 cpu_spinwait(); 404 continue; 405 } 406 if (i < 60000000 || kdb_active || panicstr != NULL) 407 DELAY(1); 408 else { 409 td = mtx_owner(m); 410 411 /* If the mutex is unlocked, try again. */ 412 if (td == NULL) 413 continue; 414 printf( 415 "spin lock %p (%s) held by %p (tid %d) too long\n", 416 m, m->mtx_object.lo_name, td, td->td_tid); 417#ifdef WITNESS 418 witness_display_spinlock(&m->mtx_object, td); 419#endif 420 panic("spin lock held too long"); 421 } 422 cpu_spinwait(); 423 } 424 spinlock_enter(); 425 } 426 427 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 428 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m); 429 430 return; 431} 432#endif /* SMP */ 433 434/* 435 * _mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock. 436 * 437 * We are only called here if the lock is recursed or contested (i.e. we 438 * need to wake up a blocked thread). 439 */ 440void 441_mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line) 442{ 443 struct turnstile *ts; 444#ifndef PREEMPTION 445 struct thread *td, *td1; 446#endif 447 448 if (mtx_recursed(m)) { 449 if (--(m->mtx_recurse) == 0) 450 atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED); 451 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 452 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m); 453 return; 454 } 455 456 turnstile_lock(&m->mtx_object); 457 ts = turnstile_lookup(&m->mtx_object); 458 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 459 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m); 460 461#if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES) 462 if (ts == NULL) { 463 _release_lock_quick(m); 464 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 465 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p no sleepers", m); 466 turnstile_release(&m->mtx_object); 467 return; 468 } 469#else 470 MPASS(ts != NULL); 471#endif 472#ifndef PREEMPTION 473 /* XXX */ 474 td1 = turnstile_head(ts, TS_EXCLUSIVE_QUEUE); 475#endif 476#ifdef MUTEX_WAKE_ALL 477 turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE); 478 _release_lock_quick(m); 479#else 480 if (turnstile_signal(ts, TS_EXCLUSIVE_QUEUE)) { 481 _release_lock_quick(m); 482 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 483 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p not held", m); 484 } else { 485 m->mtx_lock = MTX_CONTESTED; 486 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 487 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p still contested", 488 m); 489 } 490#endif 491 turnstile_unpend(ts, TS_EXCLUSIVE_LOCK); 492 493#ifndef PREEMPTION 494 /* 495 * XXX: This is just a hack until preemption is done. However, 496 * once preemption is done we need to either wrap the 497 * turnstile_signal() and release of the actual lock in an 498 * extra critical section or change the preemption code to 499 * always just set a flag and never do instant-preempts. 500 */ 501 td = curthread; 502 if (td->td_critnest > 0 || td1->td_priority >= td->td_priority) 503 return; 504 mtx_lock_spin(&sched_lock); 505 if (!TD_IS_RUNNING(td1)) { 506#ifdef notyet 507 if (td->td_ithd != NULL) { 508 struct ithd *it = td->td_ithd; 509 510 if (it->it_interrupted) { 511 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 512 CTR2(KTR_LOCK, 513 "_mtx_unlock_sleep: %p interrupted %p", 514 it, it->it_interrupted); 515 intr_thd_fixup(it); 516 } 517 } 518#endif 519 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 520 CTR2(KTR_LOCK, 521 "_mtx_unlock_sleep: %p switching out lock=%p", m, 522 (void *)m->mtx_lock); 523 524 mi_switch(SW_INVOL, NULL); 525 if (LOCK_LOG_TEST(&m->mtx_object, opts)) 526 CTR2(KTR_LOCK, "_mtx_unlock_sleep: %p resuming lock=%p", 527 m, (void *)m->mtx_lock); 528 } 529 mtx_unlock_spin(&sched_lock); 530#endif 531 532 return; 533} 534 535/* 536 * All the unlocking of MTX_SPIN locks is done inline. 537 * See the _rel_spin_lock() macro for the details. 538 */ 539 540/* 541 * The backing function for the INVARIANTS-enabled mtx_assert() 542 */ 543#ifdef INVARIANT_SUPPORT 544void 545_mtx_assert(struct mtx *m, int what, const char *file, int line) 546{ 547 548 if (panicstr != NULL || dumping) 549 return; 550 switch (what) { 551 case MA_OWNED: 552 case MA_OWNED | MA_RECURSED: 553 case MA_OWNED | MA_NOTRECURSED: 554 if (!mtx_owned(m)) 555 panic("mutex %s not owned at %s:%d", 556 m->mtx_object.lo_name, file, line); 557 if (mtx_recursed(m)) { 558 if ((what & MA_NOTRECURSED) != 0) 559 panic("mutex %s recursed at %s:%d", 560 m->mtx_object.lo_name, file, line); 561 } else if ((what & MA_RECURSED) != 0) { 562 panic("mutex %s unrecursed at %s:%d", 563 m->mtx_object.lo_name, file, line); 564 } 565 break; 566 case MA_NOTOWNED: 567 if (mtx_owned(m)) 568 panic("mutex %s owned at %s:%d", 569 m->mtx_object.lo_name, file, line); 570 break; 571 default: 572 panic("unknown mtx_assert at %s:%d", file, line); 573 } 574} 575#endif 576 577/* 578 * The MUTEX_DEBUG-enabled mtx_validate() 579 * 580 * Most of these checks have been moved off into the LO_INITIALIZED flag 581 * maintained by the witness code. 582 */ 583#ifdef MUTEX_DEBUG 584 585void mtx_validate(struct mtx *); 586 587void 588mtx_validate(struct mtx *m) 589{ 590 591/* 592 * XXX: When kernacc() does not require Giant we can reenable this check 593 */ 594#ifdef notyet 595 /* 596 * Can't call kernacc() from early init386(), especially when 597 * initializing Giant mutex, because some stuff in kernacc() 598 * requires Giant itself. 599 */ 600 if (!cold) 601 if (!kernacc((caddr_t)m, sizeof(m), 602 VM_PROT_READ | VM_PROT_WRITE)) 603 panic("Can't read and write to mutex %p", m); 604#endif 605} 606#endif 607 608/* 609 * General init routine used by the MTX_SYSINIT() macro. 610 */ 611void 612mtx_sysinit(void *arg) 613{ 614 struct mtx_args *margs = arg; 615 616 mtx_init(margs->ma_mtx, margs->ma_desc, NULL, margs->ma_opts); 617} 618 619/* 620 * Mutex initialization routine; initialize lock `m' of type contained in 621 * `opts' with options contained in `opts' and name `name.' The optional 622 * lock type `type' is used as a general lock category name for use with 623 * witness. 624 */ 625void 626mtx_init(struct mtx *m, const char *name, const char *type, int opts) 627{ 628 struct lock_class *class; 629 int flags; 630 631 MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE | 632 MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE)) == 0); 633 634#ifdef MUTEX_DEBUG 635 /* Diagnostic and error correction */ 636 mtx_validate(m); 637#endif 638 639 /* Determine lock class and lock flags. */ 640 if (opts & MTX_SPIN) 641 class = &lock_class_mtx_spin; 642 else 643 class = &lock_class_mtx_sleep; 644 flags = 0; 645 if (opts & MTX_QUIET) 646 flags |= LO_QUIET; 647 if (opts & MTX_RECURSE) 648 flags |= LO_RECURSABLE; 649 if ((opts & MTX_NOWITNESS) == 0) 650 flags |= LO_WITNESS; 651 if (opts & MTX_DUPOK) 652 flags |= LO_DUPOK; 653 if (opts & MTX_NOPROFILE) 654 flags |= LO_NOPROFILE; 655 656 /* Initialize mutex. */ 657 m->mtx_lock = MTX_UNOWNED; 658 m->mtx_recurse = 0; 659 660 lock_profile_object_init(&m->mtx_object, class, name); 661 lock_init(&m->mtx_object, class, name, type, flags); 662} 663 664/* 665 * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be 666 * passed in as a flag here because if the corresponding mtx_init() was 667 * called with MTX_QUIET set, then it will already be set in the mutex's 668 * flags. 669 */ 670void 671mtx_destroy(struct mtx *m) 672{ 673 674 if (!mtx_owned(m)) 675 MPASS(mtx_unowned(m)); 676 else { 677 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0); 678 679 /* Perform the non-mtx related part of mtx_unlock_spin(). */ 680 if (LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_spin) 681 spinlock_exit(); 682 else 683 curthread->td_locks--; 684 685 /* Tell witness this isn't locked to make it happy. */ 686 WITNESS_UNLOCK(&m->mtx_object, LOP_EXCLUSIVE, __FILE__, 687 __LINE__); 688 } 689 690 m->mtx_lock = MTX_DESTROYED; 691 lock_profile_object_destroy(&m->mtx_object); 692 lock_destroy(&m->mtx_object); 693} 694 695/* 696 * Intialize the mutex code and system mutexes. This is called from the MD 697 * startup code prior to mi_startup(). The per-CPU data space needs to be 698 * setup before this is called. 699 */ 700void 701mutex_init(void) 702{ 703 704 /* Setup turnstiles so that sleep mutexes work. */ 705 init_turnstiles(); 706 707 /* 708 * Initialize mutexes. 709 */ 710 mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE); 711 mtx_init(&sched_lock, "sched lock", NULL, MTX_SPIN | MTX_RECURSE); 712 mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK); 713 mtx_init(&devmtx, "cdev", NULL, MTX_DEF); 714 mtx_lock(&Giant); 715 716 lock_profile_init(); 717} 718 719#ifdef DDB 720void 721db_show_mtx(struct lock_object *lock) 722{ 723 struct thread *td; 724 struct mtx *m; 725 726 m = (struct mtx *)lock; 727 728 db_printf(" flags: {"); 729 if (LOCK_CLASS(lock) == &lock_class_mtx_spin) 730 db_printf("SPIN"); 731 else 732 db_printf("DEF"); 733 if (m->mtx_object.lo_flags & LO_RECURSABLE) 734 db_printf(", RECURSE"); 735 if (m->mtx_object.lo_flags & LO_DUPOK) 736 db_printf(", DUPOK"); 737 db_printf("}\n"); 738 db_printf(" state: {"); 739 if (mtx_unowned(m)) 740 db_printf("UNOWNED"); 741 else { 742 db_printf("OWNED"); 743 if (m->mtx_lock & MTX_CONTESTED) 744 db_printf(", CONTESTED"); 745 if (m->mtx_lock & MTX_RECURSED) 746 db_printf(", RECURSED"); 747 } 748 db_printf("}\n"); 749 if (!mtx_unowned(m)) { 750 td = mtx_owner(m); 751 db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td, 752 td->td_tid, td->td_proc->p_pid, td->td_proc->p_comm); 753 if (mtx_recursed(m)) 754 db_printf(" recursed: %d\n", m->mtx_recurse); 755 } 756} 757#endif 758