1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1998 Berkeley Software Design, Inc. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Berkeley Software Design Inc's name may not be used to endorse or 15 * promote products derived from this software without specific prior 16 * written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * from BSDI $Id: mutex_witness.c,v 1.1.2.20 2000/04/27 03:10:27 cp Exp $ 31 * and BSDI $Id: synch_machdep.c,v 2.3.2.39 2000/04/27 03:10:25 cp Exp $ 32 */ 33 34 /* 35 * Machine independent bits of mutex implementation. 36 */ 37 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 #include "opt_adaptive_mutexes.h" 42 #include "opt_ddb.h" 43 #include "opt_hwpmc_hooks.h" 44 #include "opt_sched.h" 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/bus.h> 49 #include <sys/conf.h> 50 #include <sys/kdb.h> 51 #include <sys/kernel.h> 52 #include <sys/ktr.h> 53 #include <sys/lock.h> 54 #include <sys/malloc.h> 55 #include <sys/mutex.h> 56 #include <sys/proc.h> 57 #include <sys/resourcevar.h> 58 #include <sys/sched.h> 59 #include <sys/sbuf.h> 60 #include <sys/smp.h> 61 #include <sys/sysctl.h> 62 #include <sys/turnstile.h> 63 #include <sys/vmmeter.h> 64 #include <sys/lock_profile.h> 65 66 #include <machine/atomic.h> 67 #include <machine/bus.h> 68 #include <machine/cpu.h> 69 70 #include <ddb/ddb.h> 71 72 #include <fs/devfs/devfs_int.h> 73 74 #include <vm/vm.h> 75 #include <vm/vm_extern.h> 76 77 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES) 78 #define ADAPTIVE_MUTEXES 79 #endif 80 81 #ifdef HWPMC_HOOKS 82 #include <sys/pmckern.h> 83 PMC_SOFT_DEFINE( , , lock, failed); 84 #endif 85 86 /* 87 * Return the mutex address when the lock cookie address is provided. 88 * This functionality assumes that struct mtx* have a member named mtx_lock. 89 */ 90 #define mtxlock2mtx(c) (__containerof(c, struct mtx, mtx_lock)) 91 92 /* 93 * Internal utility macros. 94 */ 95 #define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED) 96 97 #define mtx_destroyed(m) ((m)->mtx_lock == MTX_DESTROYED) 98 99 static void assert_mtx(const struct lock_object *lock, int what); 100 #ifdef DDB 101 static void db_show_mtx(const struct lock_object *lock); 102 #endif 103 static void lock_mtx(struct lock_object *lock, uintptr_t how); 104 static void lock_spin(struct lock_object *lock, uintptr_t how); 105 #ifdef KDTRACE_HOOKS 106 static int owner_mtx(const struct lock_object *lock, 107 struct thread **owner); 108 #endif 109 static uintptr_t unlock_mtx(struct lock_object *lock); 110 static uintptr_t unlock_spin(struct lock_object *lock); 111 112 /* 113 * Lock classes for sleep and spin mutexes. 114 */ 115 struct lock_class lock_class_mtx_sleep = { 116 .lc_name = "sleep mutex", 117 .lc_flags = LC_SLEEPLOCK | LC_RECURSABLE, 118 .lc_assert = assert_mtx, 119 #ifdef DDB 120 .lc_ddb_show = db_show_mtx, 121 #endif 122 .lc_lock = lock_mtx, 123 .lc_unlock = unlock_mtx, 124 #ifdef KDTRACE_HOOKS 125 .lc_owner = owner_mtx, 126 #endif 127 }; 128 struct lock_class lock_class_mtx_spin = { 129 .lc_name = "spin mutex", 130 .lc_flags = LC_SPINLOCK | LC_RECURSABLE, 131 .lc_assert = assert_mtx, 132 #ifdef DDB 133 .lc_ddb_show = db_show_mtx, 134 #endif 135 .lc_lock = lock_spin, 136 .lc_unlock = unlock_spin, 137 #ifdef KDTRACE_HOOKS 138 .lc_owner = owner_mtx, 139 #endif 140 }; 141 142 #ifdef ADAPTIVE_MUTEXES 143 static SYSCTL_NODE(_debug, OID_AUTO, mtx, CTLFLAG_RD, NULL, "mtx debugging"); 144 145 static struct lock_delay_config __read_frequently mtx_delay; 146 147 SYSCTL_INT(_debug_mtx, OID_AUTO, delay_base, CTLFLAG_RW, &mtx_delay.base, 148 0, ""); 149 SYSCTL_INT(_debug_mtx, OID_AUTO, delay_max, CTLFLAG_RW, &mtx_delay.max, 150 0, ""); 151 152 LOCK_DELAY_SYSINIT_DEFAULT(mtx_delay); 153 #endif 154 155 static SYSCTL_NODE(_debug, OID_AUTO, mtx_spin, CTLFLAG_RD, NULL, 156 "mtx spin debugging"); 157 158 static struct lock_delay_config __read_frequently mtx_spin_delay; 159 160 SYSCTL_INT(_debug_mtx_spin, OID_AUTO, delay_base, CTLFLAG_RW, 161 &mtx_spin_delay.base, 0, ""); 162 SYSCTL_INT(_debug_mtx_spin, OID_AUTO, delay_max, CTLFLAG_RW, 163 &mtx_spin_delay.max, 0, ""); 164 165 LOCK_DELAY_SYSINIT_DEFAULT(mtx_spin_delay); 166 167 /* 168 * System-wide mutexes 169 */ 170 struct mtx blocked_lock; 171 struct mtx __exclusive_cache_line Giant; 172 173 static void _mtx_lock_indefinite_check(struct mtx *, struct lock_delay_arg *); 174 175 void 176 assert_mtx(const struct lock_object *lock, int what) 177 { 178 179 mtx_assert((const struct mtx *)lock, what); 180 } 181 182 void 183 lock_mtx(struct lock_object *lock, uintptr_t how) 184 { 185 186 mtx_lock((struct mtx *)lock); 187 } 188 189 void 190 lock_spin(struct lock_object *lock, uintptr_t how) 191 { 192 193 panic("spin locks can only use msleep_spin"); 194 } 195 196 uintptr_t 197 unlock_mtx(struct lock_object *lock) 198 { 199 struct mtx *m; 200 201 m = (struct mtx *)lock; 202 mtx_assert(m, MA_OWNED | MA_NOTRECURSED); 203 mtx_unlock(m); 204 return (0); 205 } 206 207 uintptr_t 208 unlock_spin(struct lock_object *lock) 209 { 210 211 panic("spin locks can only use msleep_spin"); 212 } 213 214 #ifdef KDTRACE_HOOKS 215 int 216 owner_mtx(const struct lock_object *lock, struct thread **owner) 217 { 218 const struct mtx *m; 219 uintptr_t x; 220 221 m = (const struct mtx *)lock; 222 x = m->mtx_lock; 223 *owner = (struct thread *)(x & ~MTX_FLAGMASK); 224 return (*owner != NULL); 225 } 226 #endif 227 228 /* 229 * Function versions of the inlined __mtx_* macros. These are used by 230 * modules and can also be called from assembly language if needed. 231 */ 232 void 233 __mtx_lock_flags(volatile uintptr_t *c, int opts, const char *file, int line) 234 { 235 struct mtx *m; 236 uintptr_t tid, v; 237 238 m = mtxlock2mtx(c); 239 240 KASSERT(kdb_active != 0 || SCHEDULER_STOPPED() || 241 !TD_IS_IDLETHREAD(curthread), 242 ("mtx_lock() by idle thread %p on sleep mutex %s @ %s:%d", 243 curthread, m->lock_object.lo_name, file, line)); 244 KASSERT(m->mtx_lock != MTX_DESTROYED, 245 ("mtx_lock() of destroyed mutex @ %s:%d", file, line)); 246 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, 247 ("mtx_lock() of spin mutex %s @ %s:%d", m->lock_object.lo_name, 248 file, line)); 249 WITNESS_CHECKORDER(&m->lock_object, (opts & ~MTX_RECURSE) | 250 LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); 251 252 tid = (uintptr_t)curthread; 253 v = MTX_UNOWNED; 254 if (!_mtx_obtain_lock_fetch(m, &v, tid)) 255 _mtx_lock_sleep(m, v, opts, file, line); 256 else 257 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire, 258 m, 0, 0, file, line); 259 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, 260 line); 261 WITNESS_LOCK(&m->lock_object, (opts & ~MTX_RECURSE) | LOP_EXCLUSIVE, 262 file, line); 263 TD_LOCKS_INC(curthread); 264 } 265 266 void 267 __mtx_unlock_flags(volatile uintptr_t *c, int opts, const char *file, int line) 268 { 269 struct mtx *m; 270 271 m = mtxlock2mtx(c); 272 273 KASSERT(m->mtx_lock != MTX_DESTROYED, 274 ("mtx_unlock() of destroyed mutex @ %s:%d", file, line)); 275 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, 276 ("mtx_unlock() of spin mutex %s @ %s:%d", m->lock_object.lo_name, 277 file, line)); 278 WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 279 LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file, 280 line); 281 mtx_assert(m, MA_OWNED); 282 283 #ifdef LOCK_PROFILING 284 __mtx_unlock_sleep(c, (uintptr_t)curthread, opts, file, line); 285 #else 286 __mtx_unlock(m, curthread, opts, file, line); 287 #endif 288 TD_LOCKS_DEC(curthread); 289 } 290 291 void 292 __mtx_lock_spin_flags(volatile uintptr_t *c, int opts, const char *file, 293 int line) 294 { 295 struct mtx *m; 296 #ifdef SMP 297 uintptr_t tid, v; 298 #endif 299 300 m = mtxlock2mtx(c); 301 302 KASSERT(m->mtx_lock != MTX_DESTROYED, 303 ("mtx_lock_spin() of destroyed mutex @ %s:%d", file, line)); 304 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 305 ("mtx_lock_spin() of sleep mutex %s @ %s:%d", 306 m->lock_object.lo_name, file, line)); 307 if (mtx_owned(m)) 308 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0 || 309 (opts & MTX_RECURSE) != 0, 310 ("mtx_lock_spin: recursed on non-recursive mutex %s @ %s:%d\n", 311 m->lock_object.lo_name, file, line)); 312 opts &= ~MTX_RECURSE; 313 WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE, 314 file, line, NULL); 315 #ifdef SMP 316 spinlock_enter(); 317 tid = (uintptr_t)curthread; 318 v = MTX_UNOWNED; 319 if (!_mtx_obtain_lock_fetch(m, &v, tid)) 320 _mtx_lock_spin(m, v, opts, file, line); 321 else 322 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, 323 m, 0, 0, file, line); 324 #else 325 __mtx_lock_spin(m, curthread, opts, file, line); 326 #endif 327 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, 328 line); 329 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 330 } 331 332 int 333 __mtx_trylock_spin_flags(volatile uintptr_t *c, int opts, const char *file, 334 int line) 335 { 336 struct mtx *m; 337 338 if (SCHEDULER_STOPPED()) 339 return (1); 340 341 m = mtxlock2mtx(c); 342 343 KASSERT(m->mtx_lock != MTX_DESTROYED, 344 ("mtx_trylock_spin() of destroyed mutex @ %s:%d", file, line)); 345 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 346 ("mtx_trylock_spin() of sleep mutex %s @ %s:%d", 347 m->lock_object.lo_name, file, line)); 348 KASSERT((opts & MTX_RECURSE) == 0, 349 ("mtx_trylock_spin: unsupp. opt MTX_RECURSE on mutex %s @ %s:%d\n", 350 m->lock_object.lo_name, file, line)); 351 if (__mtx_trylock_spin(m, curthread, opts, file, line)) { 352 LOCK_LOG_TRY("LOCK", &m->lock_object, opts, 1, file, line); 353 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 354 return (1); 355 } 356 LOCK_LOG_TRY("LOCK", &m->lock_object, opts, 0, file, line); 357 return (0); 358 } 359 360 void 361 __mtx_unlock_spin_flags(volatile uintptr_t *c, int opts, const char *file, 362 int line) 363 { 364 struct mtx *m; 365 366 m = mtxlock2mtx(c); 367 368 KASSERT(m->mtx_lock != MTX_DESTROYED, 369 ("mtx_unlock_spin() of destroyed mutex @ %s:%d", file, line)); 370 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 371 ("mtx_unlock_spin() of sleep mutex %s @ %s:%d", 372 m->lock_object.lo_name, file, line)); 373 WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 374 LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file, 375 line); 376 mtx_assert(m, MA_OWNED); 377 378 __mtx_unlock_spin(m); 379 } 380 381 /* 382 * The important part of mtx_trylock{,_flags}() 383 * Tries to acquire lock `m.' If this function is called on a mutex that 384 * is already owned, it will recursively acquire the lock. 385 */ 386 int 387 _mtx_trylock_flags_int(struct mtx *m, int opts LOCK_FILE_LINE_ARG_DEF) 388 { 389 struct thread *td; 390 uintptr_t tid, v; 391 #ifdef LOCK_PROFILING 392 uint64_t waittime = 0; 393 int contested = 0; 394 #endif 395 int rval; 396 bool recursed; 397 398 td = curthread; 399 tid = (uintptr_t)td; 400 if (SCHEDULER_STOPPED_TD(td)) 401 return (1); 402 403 KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(td), 404 ("mtx_trylock() by idle thread %p on sleep mutex %s @ %s:%d", 405 curthread, m->lock_object.lo_name, file, line)); 406 KASSERT(m->mtx_lock != MTX_DESTROYED, 407 ("mtx_trylock() of destroyed mutex @ %s:%d", file, line)); 408 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, 409 ("mtx_trylock() of spin mutex %s @ %s:%d", m->lock_object.lo_name, 410 file, line)); 411 412 rval = 1; 413 recursed = false; 414 v = MTX_UNOWNED; 415 for (;;) { 416 if (_mtx_obtain_lock_fetch(m, &v, tid)) 417 break; 418 if (v == MTX_UNOWNED) 419 continue; 420 if (v == tid && 421 ((m->lock_object.lo_flags & LO_RECURSABLE) != 0 || 422 (opts & MTX_RECURSE) != 0)) { 423 m->mtx_recurse++; 424 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); 425 recursed = true; 426 break; 427 } 428 rval = 0; 429 break; 430 } 431 432 opts &= ~MTX_RECURSE; 433 434 LOCK_LOG_TRY("LOCK", &m->lock_object, opts, rval, file, line); 435 if (rval) { 436 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK, 437 file, line); 438 TD_LOCKS_INC(curthread); 439 if (!recursed) 440 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire, 441 m, contested, waittime, file, line); 442 } 443 444 return (rval); 445 } 446 447 int 448 _mtx_trylock_flags_(volatile uintptr_t *c, int opts, const char *file, int line) 449 { 450 struct mtx *m; 451 452 m = mtxlock2mtx(c); 453 return (_mtx_trylock_flags_int(m, opts LOCK_FILE_LINE_ARG)); 454 } 455 456 /* 457 * __mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock. 458 * 459 * We call this if the lock is either contested (i.e. we need to go to 460 * sleep waiting for it), or if we need to recurse on it. 461 */ 462 #if LOCK_DEBUG > 0 463 void 464 __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v, int opts, const char *file, 465 int line) 466 #else 467 void 468 __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v) 469 #endif 470 { 471 struct thread *td; 472 struct mtx *m; 473 struct turnstile *ts; 474 uintptr_t tid; 475 struct thread *owner; 476 #ifdef KTR 477 int cont_logged = 0; 478 #endif 479 #ifdef LOCK_PROFILING 480 int contested = 0; 481 uint64_t waittime = 0; 482 #endif 483 #if defined(ADAPTIVE_MUTEXES) || defined(KDTRACE_HOOKS) 484 struct lock_delay_arg lda; 485 #endif 486 #ifdef KDTRACE_HOOKS 487 u_int sleep_cnt = 0; 488 int64_t sleep_time = 0; 489 int64_t all_time = 0; 490 #endif 491 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 492 int doing_lockprof; 493 #endif 494 495 td = curthread; 496 tid = (uintptr_t)td; 497 m = mtxlock2mtx(c); 498 499 #ifdef KDTRACE_HOOKS 500 if (LOCKSTAT_PROFILE_ENABLED(adaptive__acquire)) { 501 while (v == MTX_UNOWNED) { 502 if (_mtx_obtain_lock_fetch(m, &v, tid)) 503 goto out_lockstat; 504 } 505 doing_lockprof = 1; 506 all_time -= lockstat_nsecs(&m->lock_object); 507 } 508 #endif 509 #ifdef LOCK_PROFILING 510 doing_lockprof = 1; 511 #endif 512 513 if (SCHEDULER_STOPPED_TD(td)) 514 return; 515 516 #if defined(ADAPTIVE_MUTEXES) 517 lock_delay_arg_init(&lda, &mtx_delay); 518 #elif defined(KDTRACE_HOOKS) 519 lock_delay_arg_init(&lda, NULL); 520 #endif 521 522 if (__predict_false(v == MTX_UNOWNED)) 523 v = MTX_READ_VALUE(m); 524 525 if (__predict_false(lv_mtx_owner(v) == td)) { 526 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0 || 527 (opts & MTX_RECURSE) != 0, 528 ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n", 529 m->lock_object.lo_name, file, line)); 530 #if LOCK_DEBUG > 0 531 opts &= ~MTX_RECURSE; 532 #endif 533 m->mtx_recurse++; 534 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); 535 if (LOCK_LOG_TEST(&m->lock_object, opts)) 536 CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m); 537 return; 538 } 539 #if LOCK_DEBUG > 0 540 opts &= ~MTX_RECURSE; 541 #endif 542 543 #ifdef HWPMC_HOOKS 544 PMC_SOFT_CALL( , , lock, failed); 545 #endif 546 lock_profile_obtain_lock_failed(&m->lock_object, 547 &contested, &waittime); 548 if (LOCK_LOG_TEST(&m->lock_object, opts)) 549 CTR4(KTR_LOCK, 550 "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d", 551 m->lock_object.lo_name, (void *)m->mtx_lock, file, line); 552 553 for (;;) { 554 if (v == MTX_UNOWNED) { 555 if (_mtx_obtain_lock_fetch(m, &v, tid)) 556 break; 557 continue; 558 } 559 #ifdef KDTRACE_HOOKS 560 lda.spin_cnt++; 561 #endif 562 #ifdef ADAPTIVE_MUTEXES 563 /* 564 * If the owner is running on another CPU, spin until the 565 * owner stops running or the state of the lock changes. 566 */ 567 owner = lv_mtx_owner(v); 568 if (TD_IS_RUNNING(owner)) { 569 if (LOCK_LOG_TEST(&m->lock_object, 0)) 570 CTR3(KTR_LOCK, 571 "%s: spinning on %p held by %p", 572 __func__, m, owner); 573 KTR_STATE1(KTR_SCHED, "thread", 574 sched_tdname((struct thread *)tid), 575 "spinning", "lockname:\"%s\"", 576 m->lock_object.lo_name); 577 do { 578 lock_delay(&lda); 579 v = MTX_READ_VALUE(m); 580 owner = lv_mtx_owner(v); 581 } while (v != MTX_UNOWNED && TD_IS_RUNNING(owner)); 582 KTR_STATE0(KTR_SCHED, "thread", 583 sched_tdname((struct thread *)tid), 584 "running"); 585 continue; 586 } 587 #endif 588 589 ts = turnstile_trywait(&m->lock_object); 590 v = MTX_READ_VALUE(m); 591 retry_turnstile: 592 593 /* 594 * Check if the lock has been released while spinning for 595 * the turnstile chain lock. 596 */ 597 if (v == MTX_UNOWNED) { 598 turnstile_cancel(ts); 599 continue; 600 } 601 602 #ifdef ADAPTIVE_MUTEXES 603 /* 604 * The current lock owner might have started executing 605 * on another CPU (or the lock could have changed 606 * owners) while we were waiting on the turnstile 607 * chain lock. If so, drop the turnstile lock and try 608 * again. 609 */ 610 owner = lv_mtx_owner(v); 611 if (TD_IS_RUNNING(owner)) { 612 turnstile_cancel(ts); 613 continue; 614 } 615 #endif 616 617 /* 618 * If the mutex isn't already contested and a failure occurs 619 * setting the contested bit, the mutex was either released 620 * or the state of the MTX_RECURSED bit changed. 621 */ 622 if ((v & MTX_CONTESTED) == 0 && 623 !atomic_fcmpset_ptr(&m->mtx_lock, &v, v | MTX_CONTESTED)) { 624 goto retry_turnstile; 625 } 626 627 /* 628 * We definitely must sleep for this lock. 629 */ 630 mtx_assert(m, MA_NOTOWNED); 631 632 #ifdef KTR 633 if (!cont_logged) { 634 CTR6(KTR_CONTENTION, 635 "contention: %p at %s:%d wants %s, taken by %s:%d", 636 (void *)tid, file, line, m->lock_object.lo_name, 637 WITNESS_FILE(&m->lock_object), 638 WITNESS_LINE(&m->lock_object)); 639 cont_logged = 1; 640 } 641 #endif 642 643 /* 644 * Block on the turnstile. 645 */ 646 #ifdef KDTRACE_HOOKS 647 sleep_time -= lockstat_nsecs(&m->lock_object); 648 #endif 649 #ifndef ADAPTIVE_MUTEXES 650 owner = mtx_owner(m); 651 #endif 652 MPASS(owner == mtx_owner(m)); 653 turnstile_wait(ts, owner, TS_EXCLUSIVE_QUEUE); 654 #ifdef KDTRACE_HOOKS 655 sleep_time += lockstat_nsecs(&m->lock_object); 656 sleep_cnt++; 657 #endif 658 v = MTX_READ_VALUE(m); 659 } 660 #ifdef KTR 661 if (cont_logged) { 662 CTR4(KTR_CONTENTION, 663 "contention end: %s acquired by %p at %s:%d", 664 m->lock_object.lo_name, (void *)tid, file, line); 665 } 666 #endif 667 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 668 if (__predict_true(!doing_lockprof)) 669 return; 670 #endif 671 #ifdef KDTRACE_HOOKS 672 all_time += lockstat_nsecs(&m->lock_object); 673 if (sleep_time) 674 LOCKSTAT_RECORD1(adaptive__block, m, sleep_time); 675 676 /* 677 * Only record the loops spinning and not sleeping. 678 */ 679 if (lda.spin_cnt > sleep_cnt) 680 LOCKSTAT_RECORD1(adaptive__spin, m, all_time - sleep_time); 681 out_lockstat: 682 #endif 683 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire, m, contested, 684 waittime, file, line); 685 } 686 687 #ifdef SMP 688 /* 689 * _mtx_lock_spin_cookie: the tougher part of acquiring an MTX_SPIN lock. 690 * 691 * This is only called if we need to actually spin for the lock. Recursion 692 * is handled inline. 693 */ 694 #if LOCK_DEBUG > 0 695 void 696 _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v, int opts, 697 const char *file, int line) 698 #else 699 void 700 _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v) 701 #endif 702 { 703 struct mtx *m; 704 struct lock_delay_arg lda; 705 uintptr_t tid; 706 #ifdef LOCK_PROFILING 707 int contested = 0; 708 uint64_t waittime = 0; 709 #endif 710 #ifdef KDTRACE_HOOKS 711 int64_t spin_time = 0; 712 #endif 713 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 714 int doing_lockprof; 715 #endif 716 717 tid = (uintptr_t)curthread; 718 m = mtxlock2mtx(c); 719 720 #ifdef KDTRACE_HOOKS 721 if (LOCKSTAT_PROFILE_ENABLED(adaptive__acquire)) { 722 while (v == MTX_UNOWNED) { 723 if (_mtx_obtain_lock_fetch(m, &v, tid)) 724 goto out_lockstat; 725 } 726 doing_lockprof = 1; 727 spin_time -= lockstat_nsecs(&m->lock_object); 728 } 729 #endif 730 #ifdef LOCK_PROFILING 731 doing_lockprof = 1; 732 #endif 733 734 if (__predict_false(v == MTX_UNOWNED)) 735 v = MTX_READ_VALUE(m); 736 737 if (__predict_false(v == tid)) { 738 m->mtx_recurse++; 739 return; 740 } 741 742 if (SCHEDULER_STOPPED()) 743 return; 744 745 lock_delay_arg_init(&lda, &mtx_spin_delay); 746 747 if (LOCK_LOG_TEST(&m->lock_object, opts)) 748 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m); 749 KTR_STATE1(KTR_SCHED, "thread", sched_tdname((struct thread *)tid), 750 "spinning", "lockname:\"%s\"", m->lock_object.lo_name); 751 752 #ifdef HWPMC_HOOKS 753 PMC_SOFT_CALL( , , lock, failed); 754 #endif 755 lock_profile_obtain_lock_failed(&m->lock_object, &contested, &waittime); 756 757 for (;;) { 758 if (v == MTX_UNOWNED) { 759 if (_mtx_obtain_lock_fetch(m, &v, tid)) 760 break; 761 continue; 762 } 763 /* Give interrupts a chance while we spin. */ 764 spinlock_exit(); 765 do { 766 if (__predict_true(lda.spin_cnt < 10000000)) { 767 lock_delay(&lda); 768 } else { 769 _mtx_lock_indefinite_check(m, &lda); 770 } 771 v = MTX_READ_VALUE(m); 772 } while (v != MTX_UNOWNED); 773 spinlock_enter(); 774 } 775 776 if (LOCK_LOG_TEST(&m->lock_object, opts)) 777 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m); 778 KTR_STATE0(KTR_SCHED, "thread", sched_tdname((struct thread *)tid), 779 "running"); 780 781 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 782 if (__predict_true(!doing_lockprof)) 783 return; 784 #endif 785 #ifdef KDTRACE_HOOKS 786 spin_time += lockstat_nsecs(&m->lock_object); 787 if (lda.spin_cnt != 0) 788 LOCKSTAT_RECORD1(spin__spin, m, spin_time); 789 out_lockstat: 790 #endif 791 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, m, 792 contested, waittime, file, line); 793 } 794 #endif /* SMP */ 795 796 #ifdef INVARIANTS 797 static void 798 thread_lock_validate(struct mtx *m, int opts, const char *file, int line) 799 { 800 801 KASSERT(m->mtx_lock != MTX_DESTROYED, 802 ("thread_lock() of destroyed mutex @ %s:%d", file, line)); 803 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 804 ("thread_lock() of sleep mutex %s @ %s:%d", 805 m->lock_object.lo_name, file, line)); 806 if (mtx_owned(m)) 807 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0, 808 ("thread_lock: recursed on non-recursive mutex %s @ %s:%d\n", 809 m->lock_object.lo_name, file, line)); 810 WITNESS_CHECKORDER(&m->lock_object, 811 opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); 812 } 813 #else 814 #define thread_lock_validate(m, opts, file, line) do { } while (0) 815 #endif 816 817 #ifndef LOCK_PROFILING 818 #if LOCK_DEBUG > 0 819 void 820 _thread_lock(struct thread *td, int opts, const char *file, int line) 821 #else 822 void 823 _thread_lock(struct thread *td) 824 #endif 825 { 826 struct mtx *m; 827 uintptr_t tid, v; 828 829 tid = (uintptr_t)curthread; 830 831 if (__predict_false(LOCKSTAT_PROFILE_ENABLED(spin__acquire))) 832 goto slowpath_noirq; 833 spinlock_enter(); 834 m = td->td_lock; 835 thread_lock_validate(m, 0, file, line); 836 v = MTX_READ_VALUE(m); 837 if (__predict_true(v == MTX_UNOWNED)) { 838 if (__predict_false(!_mtx_obtain_lock(m, tid))) 839 goto slowpath_unlocked; 840 } else if (v == tid) { 841 m->mtx_recurse++; 842 } else 843 goto slowpath_unlocked; 844 if (__predict_true(m == td->td_lock)) { 845 WITNESS_LOCK(&m->lock_object, LOP_EXCLUSIVE, file, line); 846 return; 847 } 848 MPASS(m->mtx_recurse == 0); 849 _mtx_release_lock_quick(m); 850 slowpath_unlocked: 851 spinlock_exit(); 852 slowpath_noirq: 853 #if LOCK_DEBUG > 0 854 thread_lock_flags_(td, opts, file, line); 855 #else 856 thread_lock_flags_(td, 0, 0, 0); 857 #endif 858 } 859 #endif 860 861 void 862 thread_lock_flags_(struct thread *td, int opts, const char *file, int line) 863 { 864 struct mtx *m; 865 uintptr_t tid, v; 866 struct lock_delay_arg lda; 867 #ifdef LOCK_PROFILING 868 int contested = 0; 869 uint64_t waittime = 0; 870 #endif 871 #ifdef KDTRACE_HOOKS 872 int64_t spin_time = 0; 873 #endif 874 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 875 int doing_lockprof = 1; 876 #endif 877 878 tid = (uintptr_t)curthread; 879 880 if (SCHEDULER_STOPPED()) { 881 /* 882 * Ensure that spinlock sections are balanced even when the 883 * scheduler is stopped, since we may otherwise inadvertently 884 * re-enable interrupts while dumping core. 885 */ 886 spinlock_enter(); 887 return; 888 } 889 890 lock_delay_arg_init(&lda, &mtx_spin_delay); 891 892 #ifdef HWPMC_HOOKS 893 PMC_SOFT_CALL( , , lock, failed); 894 #endif 895 896 #ifdef LOCK_PROFILING 897 doing_lockprof = 1; 898 #elif defined(KDTRACE_HOOKS) 899 doing_lockprof = lockstat_enabled; 900 if (__predict_false(doing_lockprof)) 901 spin_time -= lockstat_nsecs(&td->td_lock->lock_object); 902 #endif 903 spinlock_enter(); 904 905 for (;;) { 906 retry: 907 m = td->td_lock; 908 thread_lock_validate(m, opts, file, line); 909 v = MTX_READ_VALUE(m); 910 for (;;) { 911 if (v == MTX_UNOWNED) { 912 if (_mtx_obtain_lock_fetch(m, &v, tid)) 913 break; 914 continue; 915 } 916 if (v == tid) { 917 m->mtx_recurse++; 918 MPASS(m == td->td_lock); 919 break; 920 } 921 lock_profile_obtain_lock_failed(&m->lock_object, 922 &contested, &waittime); 923 /* Give interrupts a chance while we spin. */ 924 spinlock_exit(); 925 do { 926 if (__predict_true(lda.spin_cnt < 10000000)) { 927 lock_delay(&lda); 928 } else { 929 _mtx_lock_indefinite_check(m, &lda); 930 } 931 if (m != td->td_lock) { 932 spinlock_enter(); 933 goto retry; 934 } 935 v = MTX_READ_VALUE(m); 936 } while (v != MTX_UNOWNED); 937 spinlock_enter(); 938 } 939 if (m == td->td_lock) 940 break; 941 MPASS(m->mtx_recurse == 0); 942 _mtx_release_lock_quick(m); 943 } 944 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, 945 line); 946 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 947 948 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 949 if (__predict_true(!doing_lockprof)) 950 return; 951 #endif 952 #ifdef KDTRACE_HOOKS 953 spin_time += lockstat_nsecs(&m->lock_object); 954 #endif 955 if (m->mtx_recurse == 0) 956 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, m, 957 contested, waittime, file, line); 958 #ifdef KDTRACE_HOOKS 959 if (lda.spin_cnt != 0) 960 LOCKSTAT_RECORD1(thread__spin, m, spin_time); 961 #endif 962 } 963 964 struct mtx * 965 thread_lock_block(struct thread *td) 966 { 967 struct mtx *lock; 968 969 THREAD_LOCK_ASSERT(td, MA_OWNED); 970 lock = td->td_lock; 971 td->td_lock = &blocked_lock; 972 mtx_unlock_spin(lock); 973 974 return (lock); 975 } 976 977 void 978 thread_lock_unblock(struct thread *td, struct mtx *new) 979 { 980 mtx_assert(new, MA_OWNED); 981 MPASS(td->td_lock == &blocked_lock); 982 atomic_store_rel_ptr((volatile void *)&td->td_lock, (uintptr_t)new); 983 } 984 985 void 986 thread_lock_set(struct thread *td, struct mtx *new) 987 { 988 struct mtx *lock; 989 990 mtx_assert(new, MA_OWNED); 991 THREAD_LOCK_ASSERT(td, MA_OWNED); 992 lock = td->td_lock; 993 td->td_lock = new; 994 mtx_unlock_spin(lock); 995 } 996 997 /* 998 * __mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock. 999 * 1000 * We are only called here if the lock is recursed, contested (i.e. we 1001 * need to wake up a blocked thread) or lockstat probe is active. 1002 */ 1003 #if LOCK_DEBUG > 0 1004 void 1005 __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v, int opts, 1006 const char *file, int line) 1007 #else 1008 void 1009 __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v) 1010 #endif 1011 { 1012 struct mtx *m; 1013 struct turnstile *ts; 1014 uintptr_t tid; 1015 1016 if (SCHEDULER_STOPPED()) 1017 return; 1018 1019 tid = (uintptr_t)curthread; 1020 m = mtxlock2mtx(c); 1021 1022 if (__predict_false(v == tid)) 1023 v = MTX_READ_VALUE(m); 1024 1025 if (__predict_false(v & MTX_RECURSED)) { 1026 if (--(m->mtx_recurse) == 0) 1027 atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED); 1028 if (LOCK_LOG_TEST(&m->lock_object, opts)) 1029 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m); 1030 return; 1031 } 1032 1033 LOCKSTAT_PROFILE_RELEASE_LOCK(adaptive__release, m); 1034 if (v == tid && _mtx_release_lock(m, tid)) 1035 return; 1036 1037 /* 1038 * We have to lock the chain before the turnstile so this turnstile 1039 * can be removed from the hash list if it is empty. 1040 */ 1041 turnstile_chain_lock(&m->lock_object); 1042 _mtx_release_lock_quick(m); 1043 ts = turnstile_lookup(&m->lock_object); 1044 MPASS(ts != NULL); 1045 if (LOCK_LOG_TEST(&m->lock_object, opts)) 1046 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m); 1047 turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE); 1048 1049 /* 1050 * This turnstile is now no longer associated with the mutex. We can 1051 * unlock the chain lock so a new turnstile may take it's place. 1052 */ 1053 turnstile_unpend(ts, TS_EXCLUSIVE_LOCK); 1054 turnstile_chain_unlock(&m->lock_object); 1055 } 1056 1057 /* 1058 * All the unlocking of MTX_SPIN locks is done inline. 1059 * See the __mtx_unlock_spin() macro for the details. 1060 */ 1061 1062 /* 1063 * The backing function for the INVARIANTS-enabled mtx_assert() 1064 */ 1065 #ifdef INVARIANT_SUPPORT 1066 void 1067 __mtx_assert(const volatile uintptr_t *c, int what, const char *file, int line) 1068 { 1069 const struct mtx *m; 1070 1071 if (panicstr != NULL || dumping || SCHEDULER_STOPPED()) 1072 return; 1073 1074 m = mtxlock2mtx(c); 1075 1076 switch (what) { 1077 case MA_OWNED: 1078 case MA_OWNED | MA_RECURSED: 1079 case MA_OWNED | MA_NOTRECURSED: 1080 if (!mtx_owned(m)) 1081 panic("mutex %s not owned at %s:%d", 1082 m->lock_object.lo_name, file, line); 1083 if (mtx_recursed(m)) { 1084 if ((what & MA_NOTRECURSED) != 0) 1085 panic("mutex %s recursed at %s:%d", 1086 m->lock_object.lo_name, file, line); 1087 } else if ((what & MA_RECURSED) != 0) { 1088 panic("mutex %s unrecursed at %s:%d", 1089 m->lock_object.lo_name, file, line); 1090 } 1091 break; 1092 case MA_NOTOWNED: 1093 if (mtx_owned(m)) 1094 panic("mutex %s owned at %s:%d", 1095 m->lock_object.lo_name, file, line); 1096 break; 1097 default: 1098 panic("unknown mtx_assert at %s:%d", file, line); 1099 } 1100 } 1101 #endif 1102 1103 /* 1104 * General init routine used by the MTX_SYSINIT() macro. 1105 */ 1106 void 1107 mtx_sysinit(void *arg) 1108 { 1109 struct mtx_args *margs = arg; 1110 1111 mtx_init((struct mtx *)margs->ma_mtx, margs->ma_desc, NULL, 1112 margs->ma_opts); 1113 } 1114 1115 /* 1116 * Mutex initialization routine; initialize lock `m' of type contained in 1117 * `opts' with options contained in `opts' and name `name.' The optional 1118 * lock type `type' is used as a general lock category name for use with 1119 * witness. 1120 */ 1121 void 1122 _mtx_init(volatile uintptr_t *c, const char *name, const char *type, int opts) 1123 { 1124 struct mtx *m; 1125 struct lock_class *class; 1126 int flags; 1127 1128 m = mtxlock2mtx(c); 1129 1130 MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE | 1131 MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE | MTX_NEW)) == 0); 1132 ASSERT_ATOMIC_LOAD_PTR(m->mtx_lock, 1133 ("%s: mtx_lock not aligned for %s: %p", __func__, name, 1134 &m->mtx_lock)); 1135 1136 /* Determine lock class and lock flags. */ 1137 if (opts & MTX_SPIN) 1138 class = &lock_class_mtx_spin; 1139 else 1140 class = &lock_class_mtx_sleep; 1141 flags = 0; 1142 if (opts & MTX_QUIET) 1143 flags |= LO_QUIET; 1144 if (opts & MTX_RECURSE) 1145 flags |= LO_RECURSABLE; 1146 if ((opts & MTX_NOWITNESS) == 0) 1147 flags |= LO_WITNESS; 1148 if (opts & MTX_DUPOK) 1149 flags |= LO_DUPOK; 1150 if (opts & MTX_NOPROFILE) 1151 flags |= LO_NOPROFILE; 1152 if (opts & MTX_NEW) 1153 flags |= LO_NEW; 1154 1155 /* Initialize mutex. */ 1156 lock_init(&m->lock_object, class, name, type, flags); 1157 1158 m->mtx_lock = MTX_UNOWNED; 1159 m->mtx_recurse = 0; 1160 } 1161 1162 /* 1163 * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be 1164 * passed in as a flag here because if the corresponding mtx_init() was 1165 * called with MTX_QUIET set, then it will already be set in the mutex's 1166 * flags. 1167 */ 1168 void 1169 _mtx_destroy(volatile uintptr_t *c) 1170 { 1171 struct mtx *m; 1172 1173 m = mtxlock2mtx(c); 1174 1175 if (!mtx_owned(m)) 1176 MPASS(mtx_unowned(m)); 1177 else { 1178 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0); 1179 1180 /* Perform the non-mtx related part of mtx_unlock_spin(). */ 1181 if (LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin) 1182 spinlock_exit(); 1183 else 1184 TD_LOCKS_DEC(curthread); 1185 1186 lock_profile_release_lock(&m->lock_object); 1187 /* Tell witness this isn't locked to make it happy. */ 1188 WITNESS_UNLOCK(&m->lock_object, LOP_EXCLUSIVE, __FILE__, 1189 __LINE__); 1190 } 1191 1192 m->mtx_lock = MTX_DESTROYED; 1193 lock_destroy(&m->lock_object); 1194 } 1195 1196 /* 1197 * Intialize the mutex code and system mutexes. This is called from the MD 1198 * startup code prior to mi_startup(). The per-CPU data space needs to be 1199 * setup before this is called. 1200 */ 1201 void 1202 mutex_init(void) 1203 { 1204 1205 /* Setup turnstiles so that sleep mutexes work. */ 1206 init_turnstiles(); 1207 1208 /* 1209 * Initialize mutexes. 1210 */ 1211 mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE); 1212 mtx_init(&blocked_lock, "blocked lock", NULL, MTX_SPIN); 1213 blocked_lock.mtx_lock = 0xdeadc0de; /* Always blocked. */ 1214 mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK); 1215 mtx_init(&proc0.p_slock, "process slock", NULL, MTX_SPIN); 1216 mtx_init(&proc0.p_statmtx, "pstatl", NULL, MTX_SPIN); 1217 mtx_init(&proc0.p_itimmtx, "pitiml", NULL, MTX_SPIN); 1218 mtx_init(&proc0.p_profmtx, "pprofl", NULL, MTX_SPIN); 1219 mtx_init(&devmtx, "cdev", NULL, MTX_DEF); 1220 mtx_lock(&Giant); 1221 } 1222 1223 static void __noinline 1224 _mtx_lock_indefinite_check(struct mtx *m, struct lock_delay_arg *ldap) 1225 { 1226 struct thread *td; 1227 1228 ldap->spin_cnt++; 1229 if (ldap->spin_cnt < 60000000 || kdb_active || panicstr != NULL) 1230 DELAY(1); 1231 else { 1232 td = mtx_owner(m); 1233 1234 /* If the mutex is unlocked, try again. */ 1235 if (td == NULL) 1236 return; 1237 1238 printf( "spin lock %p (%s) held by %p (tid %d) too long\n", 1239 m, m->lock_object.lo_name, td, td->td_tid); 1240 #ifdef WITNESS 1241 witness_display_spinlock(&m->lock_object, td, printf); 1242 #endif 1243 panic("spin lock held too long"); 1244 } 1245 cpu_spinwait(); 1246 } 1247 1248 void 1249 mtx_spin_wait_unlocked(struct mtx *m) 1250 { 1251 struct lock_delay_arg lda; 1252 1253 KASSERT(m->mtx_lock != MTX_DESTROYED, 1254 ("%s() of destroyed mutex %p", __func__, m)); 1255 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 1256 ("%s() of sleep mutex %p (%s)", __func__, m, 1257 m->lock_object.lo_name)); 1258 KASSERT(!mtx_owned(m), ("%s() waiting on myself on lock %p (%s)", __func__, m, 1259 m->lock_object.lo_name)); 1260 1261 lda.spin_cnt = 0; 1262 1263 while (atomic_load_acq_ptr(&m->mtx_lock) != MTX_UNOWNED) { 1264 if (__predict_true(lda.spin_cnt < 10000000)) { 1265 cpu_spinwait(); 1266 lda.spin_cnt++; 1267 } else { 1268 _mtx_lock_indefinite_check(m, &lda); 1269 } 1270 } 1271 } 1272 1273 #ifdef DDB 1274 void 1275 db_show_mtx(const struct lock_object *lock) 1276 { 1277 struct thread *td; 1278 const struct mtx *m; 1279 1280 m = (const struct mtx *)lock; 1281 1282 db_printf(" flags: {"); 1283 if (LOCK_CLASS(lock) == &lock_class_mtx_spin) 1284 db_printf("SPIN"); 1285 else 1286 db_printf("DEF"); 1287 if (m->lock_object.lo_flags & LO_RECURSABLE) 1288 db_printf(", RECURSE"); 1289 if (m->lock_object.lo_flags & LO_DUPOK) 1290 db_printf(", DUPOK"); 1291 db_printf("}\n"); 1292 db_printf(" state: {"); 1293 if (mtx_unowned(m)) 1294 db_printf("UNOWNED"); 1295 else if (mtx_destroyed(m)) 1296 db_printf("DESTROYED"); 1297 else { 1298 db_printf("OWNED"); 1299 if (m->mtx_lock & MTX_CONTESTED) 1300 db_printf(", CONTESTED"); 1301 if (m->mtx_lock & MTX_RECURSED) 1302 db_printf(", RECURSED"); 1303 } 1304 db_printf("}\n"); 1305 if (!mtx_unowned(m) && !mtx_destroyed(m)) { 1306 td = mtx_owner(m); 1307 db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td, 1308 td->td_tid, td->td_proc->p_pid, td->td_name); 1309 if (mtx_recursed(m)) 1310 db_printf(" recursed: %d\n", m->mtx_recurse); 1311 } 1312 } 1313 #endif 1314