Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/kern/kern_mutex.c
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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: releng/12.0/sys/kern/kern_mutex.c 340269 2018-11-08 22:39:38Z jhb $"); 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 LOCK_PROFILING 477 int contested = 0; 478 uint64_t waittime = 0; 479 #endif 480 #if defined(ADAPTIVE_MUTEXES) || defined(KDTRACE_HOOKS) 481 struct lock_delay_arg lda; 482 #endif 483 #ifdef KDTRACE_HOOKS 484 u_int sleep_cnt = 0; 485 int64_t sleep_time = 0; 486 int64_t all_time = 0; 487 #endif 488 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 489 int doing_lockprof; 490 #endif 491 492 td = curthread; 493 tid = (uintptr_t)td; 494 m = mtxlock2mtx(c); 495 496 #ifdef KDTRACE_HOOKS 497 if (LOCKSTAT_PROFILE_ENABLED(adaptive__acquire)) { 498 while (v == MTX_UNOWNED) { 499 if (_mtx_obtain_lock_fetch(m, &v, tid)) 500 goto out_lockstat; 501 } 502 doing_lockprof = 1; 503 all_time -= lockstat_nsecs(&m->lock_object); 504 } 505 #endif 506 #ifdef LOCK_PROFILING 507 doing_lockprof = 1; 508 #endif 509 510 if (SCHEDULER_STOPPED_TD(td)) 511 return; 512 513 #if defined(ADAPTIVE_MUTEXES) 514 lock_delay_arg_init(&lda, &mtx_delay); 515 #elif defined(KDTRACE_HOOKS) 516 lock_delay_arg_init(&lda, NULL); 517 #endif 518 519 if (__predict_false(v == MTX_UNOWNED)) 520 v = MTX_READ_VALUE(m); 521 522 if (__predict_false(lv_mtx_owner(v) == td)) { 523 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0 || 524 (opts & MTX_RECURSE) != 0, 525 ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n", 526 m->lock_object.lo_name, file, line)); 527 #if LOCK_DEBUG > 0 528 opts &= ~MTX_RECURSE; 529 #endif 530 m->mtx_recurse++; 531 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); 532 if (LOCK_LOG_TEST(&m->lock_object, opts)) 533 CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m); 534 return; 535 } 536 #if LOCK_DEBUG > 0 537 opts &= ~MTX_RECURSE; 538 #endif 539 540 #ifdef HWPMC_HOOKS 541 PMC_SOFT_CALL( , , lock, failed); 542 #endif 543 lock_profile_obtain_lock_failed(&m->lock_object, 544 &contested, &waittime); 545 if (LOCK_LOG_TEST(&m->lock_object, opts)) 546 CTR4(KTR_LOCK, 547 "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d", 548 m->lock_object.lo_name, (void *)m->mtx_lock, file, line); 549 550 for (;;) { 551 if (v == MTX_UNOWNED) { 552 if (_mtx_obtain_lock_fetch(m, &v, tid)) 553 break; 554 continue; 555 } 556 #ifdef KDTRACE_HOOKS 557 lda.spin_cnt++; 558 #endif 559 #ifdef ADAPTIVE_MUTEXES 560 /* 561 * If the owner is running on another CPU, spin until the 562 * owner stops running or the state of the lock changes. 563 */ 564 owner = lv_mtx_owner(v); 565 if (TD_IS_RUNNING(owner)) { 566 if (LOCK_LOG_TEST(&m->lock_object, 0)) 567 CTR3(KTR_LOCK, 568 "%s: spinning on %p held by %p", 569 __func__, m, owner); 570 KTR_STATE1(KTR_SCHED, "thread", 571 sched_tdname((struct thread *)tid), 572 "spinning", "lockname:\"%s\"", 573 m->lock_object.lo_name); 574 do { 575 lock_delay(&lda); 576 v = MTX_READ_VALUE(m); 577 owner = lv_mtx_owner(v); 578 } while (v != MTX_UNOWNED && TD_IS_RUNNING(owner)); 579 KTR_STATE0(KTR_SCHED, "thread", 580 sched_tdname((struct thread *)tid), 581 "running"); 582 continue; 583 } 584 #endif 585 586 ts = turnstile_trywait(&m->lock_object); 587 v = MTX_READ_VALUE(m); 588 retry_turnstile: 589 590 /* 591 * Check if the lock has been released while spinning for 592 * the turnstile chain lock. 593 */ 594 if (v == MTX_UNOWNED) { 595 turnstile_cancel(ts); 596 continue; 597 } 598 599 #ifdef ADAPTIVE_MUTEXES 600 /* 601 * The current lock owner might have started executing 602 * on another CPU (or the lock could have changed 603 * owners) while we were waiting on the turnstile 604 * chain lock. If so, drop the turnstile lock and try 605 * again. 606 */ 607 owner = lv_mtx_owner(v); 608 if (TD_IS_RUNNING(owner)) { 609 turnstile_cancel(ts); 610 continue; 611 } 612 #endif 613 614 /* 615 * If the mutex isn't already contested and a failure occurs 616 * setting the contested bit, the mutex was either released 617 * or the state of the MTX_RECURSED bit changed. 618 */ 619 if ((v & MTX_CONTESTED) == 0 && 620 !atomic_fcmpset_ptr(&m->mtx_lock, &v, v | MTX_CONTESTED)) { 621 goto retry_turnstile; 622 } 623 624 /* 625 * We definitely must sleep for this lock. 626 */ 627 mtx_assert(m, MA_NOTOWNED); 628 629 /* 630 * Block on the turnstile. 631 */ 632 #ifdef KDTRACE_HOOKS 633 sleep_time -= lockstat_nsecs(&m->lock_object); 634 #endif 635 #ifndef ADAPTIVE_MUTEXES 636 owner = mtx_owner(m); 637 #endif 638 MPASS(owner == mtx_owner(m)); 639 turnstile_wait(ts, owner, TS_EXCLUSIVE_QUEUE); 640 #ifdef KDTRACE_HOOKS 641 sleep_time += lockstat_nsecs(&m->lock_object); 642 sleep_cnt++; 643 #endif 644 v = MTX_READ_VALUE(m); 645 } 646 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 647 if (__predict_true(!doing_lockprof)) 648 return; 649 #endif 650 #ifdef KDTRACE_HOOKS 651 all_time += lockstat_nsecs(&m->lock_object); 652 if (sleep_time) 653 LOCKSTAT_RECORD1(adaptive__block, m, sleep_time); 654 655 /* 656 * Only record the loops spinning and not sleeping. 657 */ 658 if (lda.spin_cnt > sleep_cnt) 659 LOCKSTAT_RECORD1(adaptive__spin, m, all_time - sleep_time); 660 out_lockstat: 661 #endif 662 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire, m, contested, 663 waittime, file, line); 664 } 665 666 #ifdef SMP 667 /* 668 * _mtx_lock_spin_cookie: the tougher part of acquiring an MTX_SPIN lock. 669 * 670 * This is only called if we need to actually spin for the lock. Recursion 671 * is handled inline. 672 */ 673 #if LOCK_DEBUG > 0 674 void 675 _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v, int opts, 676 const char *file, int line) 677 #else 678 void 679 _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v) 680 #endif 681 { 682 struct mtx *m; 683 struct lock_delay_arg lda; 684 uintptr_t tid; 685 #ifdef LOCK_PROFILING 686 int contested = 0; 687 uint64_t waittime = 0; 688 #endif 689 #ifdef KDTRACE_HOOKS 690 int64_t spin_time = 0; 691 #endif 692 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 693 int doing_lockprof; 694 #endif 695 696 tid = (uintptr_t)curthread; 697 m = mtxlock2mtx(c); 698 699 #ifdef KDTRACE_HOOKS 700 if (LOCKSTAT_PROFILE_ENABLED(adaptive__acquire)) { 701 while (v == MTX_UNOWNED) { 702 if (_mtx_obtain_lock_fetch(m, &v, tid)) 703 goto out_lockstat; 704 } 705 doing_lockprof = 1; 706 spin_time -= lockstat_nsecs(&m->lock_object); 707 } 708 #endif 709 #ifdef LOCK_PROFILING 710 doing_lockprof = 1; 711 #endif 712 713 if (__predict_false(v == MTX_UNOWNED)) 714 v = MTX_READ_VALUE(m); 715 716 if (__predict_false(v == tid)) { 717 m->mtx_recurse++; 718 return; 719 } 720 721 if (SCHEDULER_STOPPED()) 722 return; 723 724 lock_delay_arg_init(&lda, &mtx_spin_delay); 725 726 if (LOCK_LOG_TEST(&m->lock_object, opts)) 727 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m); 728 KTR_STATE1(KTR_SCHED, "thread", sched_tdname((struct thread *)tid), 729 "spinning", "lockname:\"%s\"", m->lock_object.lo_name); 730 731 #ifdef HWPMC_HOOKS 732 PMC_SOFT_CALL( , , lock, failed); 733 #endif 734 lock_profile_obtain_lock_failed(&m->lock_object, &contested, &waittime); 735 736 for (;;) { 737 if (v == MTX_UNOWNED) { 738 if (_mtx_obtain_lock_fetch(m, &v, tid)) 739 break; 740 continue; 741 } 742 /* Give interrupts a chance while we spin. */ 743 spinlock_exit(); 744 do { 745 if (__predict_true(lda.spin_cnt < 10000000)) { 746 lock_delay(&lda); 747 } else { 748 _mtx_lock_indefinite_check(m, &lda); 749 } 750 v = MTX_READ_VALUE(m); 751 } while (v != MTX_UNOWNED); 752 spinlock_enter(); 753 } 754 755 if (LOCK_LOG_TEST(&m->lock_object, opts)) 756 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m); 757 KTR_STATE0(KTR_SCHED, "thread", sched_tdname((struct thread *)tid), 758 "running"); 759 760 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 761 if (__predict_true(!doing_lockprof)) 762 return; 763 #endif 764 #ifdef KDTRACE_HOOKS 765 spin_time += lockstat_nsecs(&m->lock_object); 766 if (lda.spin_cnt != 0) 767 LOCKSTAT_RECORD1(spin__spin, m, spin_time); 768 out_lockstat: 769 #endif 770 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, m, 771 contested, waittime, file, line); 772 } 773 #endif /* SMP */ 774 775 #ifdef INVARIANTS 776 static void 777 thread_lock_validate(struct mtx *m, int opts, const char *file, int line) 778 { 779 780 KASSERT(m->mtx_lock != MTX_DESTROYED, 781 ("thread_lock() of destroyed mutex @ %s:%d", file, line)); 782 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 783 ("thread_lock() of sleep mutex %s @ %s:%d", 784 m->lock_object.lo_name, file, line)); 785 if (mtx_owned(m)) 786 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0, 787 ("thread_lock: recursed on non-recursive mutex %s @ %s:%d\n", 788 m->lock_object.lo_name, file, line)); 789 WITNESS_CHECKORDER(&m->lock_object, 790 opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); 791 } 792 #else 793 #define thread_lock_validate(m, opts, file, line) do { } while (0) 794 #endif 795 796 #ifndef LOCK_PROFILING 797 #if LOCK_DEBUG > 0 798 void 799 _thread_lock(struct thread *td, int opts, const char *file, int line) 800 #else 801 void 802 _thread_lock(struct thread *td) 803 #endif 804 { 805 struct mtx *m; 806 uintptr_t tid, v; 807 808 tid = (uintptr_t)curthread; 809 810 if (__predict_false(LOCKSTAT_PROFILE_ENABLED(spin__acquire))) 811 goto slowpath_noirq; 812 spinlock_enter(); 813 m = td->td_lock; 814 thread_lock_validate(m, 0, file, line); 815 v = MTX_READ_VALUE(m); 816 if (__predict_true(v == MTX_UNOWNED)) { 817 if (__predict_false(!_mtx_obtain_lock(m, tid))) 818 goto slowpath_unlocked; 819 } else if (v == tid) { 820 m->mtx_recurse++; 821 } else 822 goto slowpath_unlocked; 823 if (__predict_true(m == td->td_lock)) { 824 WITNESS_LOCK(&m->lock_object, LOP_EXCLUSIVE, file, line); 825 return; 826 } 827 MPASS(m->mtx_recurse == 0); 828 _mtx_release_lock_quick(m); 829 slowpath_unlocked: 830 spinlock_exit(); 831 slowpath_noirq: 832 #if LOCK_DEBUG > 0 833 thread_lock_flags_(td, opts, file, line); 834 #else 835 thread_lock_flags_(td, 0, 0, 0); 836 #endif 837 } 838 #endif 839 840 void 841 thread_lock_flags_(struct thread *td, int opts, const char *file, int line) 842 { 843 struct mtx *m; 844 uintptr_t tid, v; 845 struct lock_delay_arg lda; 846 #ifdef LOCK_PROFILING 847 int contested = 0; 848 uint64_t waittime = 0; 849 #endif 850 #ifdef KDTRACE_HOOKS 851 int64_t spin_time = 0; 852 #endif 853 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 854 int doing_lockprof = 1; 855 #endif 856 857 tid = (uintptr_t)curthread; 858 859 if (SCHEDULER_STOPPED()) { 860 /* 861 * Ensure that spinlock sections are balanced even when the 862 * scheduler is stopped, since we may otherwise inadvertently 863 * re-enable interrupts while dumping core. 864 */ 865 spinlock_enter(); 866 return; 867 } 868 869 lock_delay_arg_init(&lda, &mtx_spin_delay); 870 871 #ifdef HWPMC_HOOKS 872 PMC_SOFT_CALL( , , lock, failed); 873 #endif 874 875 #ifdef LOCK_PROFILING 876 doing_lockprof = 1; 877 #elif defined(KDTRACE_HOOKS) 878 doing_lockprof = lockstat_enabled; 879 if (__predict_false(doing_lockprof)) 880 spin_time -= lockstat_nsecs(&td->td_lock->lock_object); 881 #endif 882 spinlock_enter(); 883 884 for (;;) { 885 retry: 886 m = td->td_lock; 887 thread_lock_validate(m, opts, file, line); 888 v = MTX_READ_VALUE(m); 889 for (;;) { 890 if (v == MTX_UNOWNED) { 891 if (_mtx_obtain_lock_fetch(m, &v, tid)) 892 break; 893 continue; 894 } 895 if (v == tid) { 896 m->mtx_recurse++; 897 MPASS(m == td->td_lock); 898 break; 899 } 900 lock_profile_obtain_lock_failed(&m->lock_object, 901 &contested, &waittime); 902 /* Give interrupts a chance while we spin. */ 903 spinlock_exit(); 904 do { 905 if (__predict_true(lda.spin_cnt < 10000000)) { 906 lock_delay(&lda); 907 } else { 908 _mtx_lock_indefinite_check(m, &lda); 909 } 910 if (m != td->td_lock) { 911 spinlock_enter(); 912 goto retry; 913 } 914 v = MTX_READ_VALUE(m); 915 } while (v != MTX_UNOWNED); 916 spinlock_enter(); 917 } 918 if (m == td->td_lock) 919 break; 920 MPASS(m->mtx_recurse == 0); 921 _mtx_release_lock_quick(m); 922 } 923 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, 924 line); 925 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 926 927 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 928 if (__predict_true(!doing_lockprof)) 929 return; 930 #endif 931 #ifdef KDTRACE_HOOKS 932 spin_time += lockstat_nsecs(&m->lock_object); 933 #endif 934 if (m->mtx_recurse == 0) 935 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, m, 936 contested, waittime, file, line); 937 #ifdef KDTRACE_HOOKS 938 if (lda.spin_cnt != 0) 939 LOCKSTAT_RECORD1(thread__spin, m, spin_time); 940 #endif 941 } 942 943 struct mtx * 944 thread_lock_block(struct thread *td) 945 { 946 struct mtx *lock; 947 948 THREAD_LOCK_ASSERT(td, MA_OWNED); 949 lock = td->td_lock; 950 td->td_lock = &blocked_lock; 951 mtx_unlock_spin(lock); 952 953 return (lock); 954 } 955 956 void 957 thread_lock_unblock(struct thread *td, struct mtx *new) 958 { 959 mtx_assert(new, MA_OWNED); 960 MPASS(td->td_lock == &blocked_lock); 961 atomic_store_rel_ptr((volatile void *)&td->td_lock, (uintptr_t)new); 962 } 963 964 void 965 thread_lock_set(struct thread *td, struct mtx *new) 966 { 967 struct mtx *lock; 968 969 mtx_assert(new, MA_OWNED); 970 THREAD_LOCK_ASSERT(td, MA_OWNED); 971 lock = td->td_lock; 972 td->td_lock = new; 973 mtx_unlock_spin(lock); 974 } 975 976 /* 977 * __mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock. 978 * 979 * We are only called here if the lock is recursed, contested (i.e. we 980 * need to wake up a blocked thread) or lockstat probe is active. 981 */ 982 #if LOCK_DEBUG > 0 983 void 984 __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v, int opts, 985 const char *file, int line) 986 #else 987 void 988 __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v) 989 #endif 990 { 991 struct mtx *m; 992 struct turnstile *ts; 993 uintptr_t tid; 994 995 if (SCHEDULER_STOPPED()) 996 return; 997 998 tid = (uintptr_t)curthread; 999 m = mtxlock2mtx(c); 1000 1001 if (__predict_false(v == tid)) 1002 v = MTX_READ_VALUE(m); 1003 1004 if (__predict_false(v & MTX_RECURSED)) { 1005 if (--(m->mtx_recurse) == 0) 1006 atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED); 1007 if (LOCK_LOG_TEST(&m->lock_object, opts)) 1008 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m); 1009 return; 1010 } 1011 1012 LOCKSTAT_PROFILE_RELEASE_LOCK(adaptive__release, m); 1013 if (v == tid && _mtx_release_lock(m, tid)) 1014 return; 1015 1016 /* 1017 * We have to lock the chain before the turnstile so this turnstile 1018 * can be removed from the hash list if it is empty. 1019 */ 1020 turnstile_chain_lock(&m->lock_object); 1021 _mtx_release_lock_quick(m); 1022 ts = turnstile_lookup(&m->lock_object); 1023 MPASS(ts != NULL); 1024 if (LOCK_LOG_TEST(&m->lock_object, opts)) 1025 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m); 1026 turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE); 1027 1028 /* 1029 * This turnstile is now no longer associated with the mutex. We can 1030 * unlock the chain lock so a new turnstile may take it's place. 1031 */ 1032 turnstile_unpend(ts); 1033 turnstile_chain_unlock(&m->lock_object); 1034 } 1035 1036 /* 1037 * All the unlocking of MTX_SPIN locks is done inline. 1038 * See the __mtx_unlock_spin() macro for the details. 1039 */ 1040 1041 /* 1042 * The backing function for the INVARIANTS-enabled mtx_assert() 1043 */ 1044 #ifdef INVARIANT_SUPPORT 1045 void 1046 __mtx_assert(const volatile uintptr_t *c, int what, const char *file, int line) 1047 { 1048 const struct mtx *m; 1049 1050 if (panicstr != NULL || dumping || SCHEDULER_STOPPED()) 1051 return; 1052 1053 m = mtxlock2mtx(c); 1054 1055 switch (what) { 1056 case MA_OWNED: 1057 case MA_OWNED | MA_RECURSED: 1058 case MA_OWNED | MA_NOTRECURSED: 1059 if (!mtx_owned(m)) 1060 panic("mutex %s not owned at %s:%d", 1061 m->lock_object.lo_name, file, line); 1062 if (mtx_recursed(m)) { 1063 if ((what & MA_NOTRECURSED) != 0) 1064 panic("mutex %s recursed at %s:%d", 1065 m->lock_object.lo_name, file, line); 1066 } else if ((what & MA_RECURSED) != 0) { 1067 panic("mutex %s unrecursed at %s:%d", 1068 m->lock_object.lo_name, file, line); 1069 } 1070 break; 1071 case MA_NOTOWNED: 1072 if (mtx_owned(m)) 1073 panic("mutex %s owned at %s:%d", 1074 m->lock_object.lo_name, file, line); 1075 break; 1076 default: 1077 panic("unknown mtx_assert at %s:%d", file, line); 1078 } 1079 } 1080 #endif 1081 1082 /* 1083 * General init routine used by the MTX_SYSINIT() macro. 1084 */ 1085 void 1086 mtx_sysinit(void *arg) 1087 { 1088 struct mtx_args *margs = arg; 1089 1090 mtx_init((struct mtx *)margs->ma_mtx, margs->ma_desc, NULL, 1091 margs->ma_opts); 1092 } 1093 1094 /* 1095 * Mutex initialization routine; initialize lock `m' of type contained in 1096 * `opts' with options contained in `opts' and name `name.' The optional 1097 * lock type `type' is used as a general lock category name for use with 1098 * witness. 1099 */ 1100 void 1101 _mtx_init(volatile uintptr_t *c, const char *name, const char *type, int opts) 1102 { 1103 struct mtx *m; 1104 struct lock_class *class; 1105 int flags; 1106 1107 m = mtxlock2mtx(c); 1108 1109 MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE | 1110 MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE | MTX_NEW)) == 0); 1111 ASSERT_ATOMIC_LOAD_PTR(m->mtx_lock, 1112 ("%s: mtx_lock not aligned for %s: %p", __func__, name, 1113 &m->mtx_lock)); 1114 1115 /* Determine lock class and lock flags. */ 1116 if (opts & MTX_SPIN) 1117 class = &lock_class_mtx_spin; 1118 else 1119 class = &lock_class_mtx_sleep; 1120 flags = 0; 1121 if (opts & MTX_QUIET) 1122 flags |= LO_QUIET; 1123 if (opts & MTX_RECURSE) 1124 flags |= LO_RECURSABLE; 1125 if ((opts & MTX_NOWITNESS) == 0) 1126 flags |= LO_WITNESS; 1127 if (opts & MTX_DUPOK) 1128 flags |= LO_DUPOK; 1129 if (opts & MTX_NOPROFILE) 1130 flags |= LO_NOPROFILE; 1131 if (opts & MTX_NEW) 1132 flags |= LO_NEW; 1133 1134 /* Initialize mutex. */ 1135 lock_init(&m->lock_object, class, name, type, flags); 1136 1137 m->mtx_lock = MTX_UNOWNED; 1138 m->mtx_recurse = 0; 1139 } 1140 1141 /* 1142 * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be 1143 * passed in as a flag here because if the corresponding mtx_init() was 1144 * called with MTX_QUIET set, then it will already be set in the mutex's 1145 * flags. 1146 */ 1147 void 1148 _mtx_destroy(volatile uintptr_t *c) 1149 { 1150 struct mtx *m; 1151 1152 m = mtxlock2mtx(c); 1153 1154 if (!mtx_owned(m)) 1155 MPASS(mtx_unowned(m)); 1156 else { 1157 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0); 1158 1159 /* Perform the non-mtx related part of mtx_unlock_spin(). */ 1160 if (LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin) 1161 spinlock_exit(); 1162 else 1163 TD_LOCKS_DEC(curthread); 1164 1165 lock_profile_release_lock(&m->lock_object); 1166 /* Tell witness this isn't locked to make it happy. */ 1167 WITNESS_UNLOCK(&m->lock_object, LOP_EXCLUSIVE, __FILE__, 1168 __LINE__); 1169 } 1170 1171 m->mtx_lock = MTX_DESTROYED; 1172 lock_destroy(&m->lock_object); 1173 } 1174 1175 /* 1176 * Intialize the mutex code and system mutexes. This is called from the MD 1177 * startup code prior to mi_startup(). The per-CPU data space needs to be 1178 * setup before this is called. 1179 */ 1180 void 1181 mutex_init(void) 1182 { 1183 1184 /* Setup turnstiles so that sleep mutexes work. */ 1185 init_turnstiles(); 1186 1187 /* 1188 * Initialize mutexes. 1189 */ 1190 mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE); 1191 mtx_init(&blocked_lock, "blocked lock", NULL, MTX_SPIN); 1192 blocked_lock.mtx_lock = 0xdeadc0de; /* Always blocked. */ 1193 mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK); 1194 mtx_init(&proc0.p_slock, "process slock", NULL, MTX_SPIN); 1195 mtx_init(&proc0.p_statmtx, "pstatl", NULL, MTX_SPIN); 1196 mtx_init(&proc0.p_itimmtx, "pitiml", NULL, MTX_SPIN); 1197 mtx_init(&proc0.p_profmtx, "pprofl", NULL, MTX_SPIN); 1198 mtx_init(&devmtx, "cdev", NULL, MTX_DEF); 1199 mtx_lock(&Giant); 1200 } 1201 1202 static void __noinline 1203 _mtx_lock_indefinite_check(struct mtx *m, struct lock_delay_arg *ldap) 1204 { 1205 struct thread *td; 1206 1207 ldap->spin_cnt++; 1208 if (ldap->spin_cnt < 60000000 || kdb_active || panicstr != NULL) 1209 cpu_lock_delay(); 1210 else { 1211 td = mtx_owner(m); 1212 1213 /* If the mutex is unlocked, try again. */ 1214 if (td == NULL) 1215 return; 1216 1217 printf( "spin lock %p (%s) held by %p (tid %d) too long\n", 1218 m, m->lock_object.lo_name, td, td->td_tid); 1219 #ifdef WITNESS 1220 witness_display_spinlock(&m->lock_object, td, printf); 1221 #endif 1222 panic("spin lock held too long"); 1223 } 1224 cpu_spinwait(); 1225 } 1226 1227 void 1228 mtx_spin_wait_unlocked(struct mtx *m) 1229 { 1230 struct lock_delay_arg lda; 1231 1232 KASSERT(m->mtx_lock != MTX_DESTROYED, 1233 ("%s() of destroyed mutex %p", __func__, m)); 1234 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 1235 ("%s() of sleep mutex %p (%s)", __func__, m, 1236 m->lock_object.lo_name)); 1237 KASSERT(!mtx_owned(m), ("%s() waiting on myself on lock %p (%s)", __func__, m, 1238 m->lock_object.lo_name)); 1239 1240 lda.spin_cnt = 0; 1241 1242 while (atomic_load_acq_ptr(&m->mtx_lock) != MTX_UNOWNED) { 1243 if (__predict_true(lda.spin_cnt < 10000000)) { 1244 cpu_spinwait(); 1245 lda.spin_cnt++; 1246 } else { 1247 _mtx_lock_indefinite_check(m, &lda); 1248 } 1249 } 1250 } 1251 1252 #ifdef DDB 1253 void 1254 db_show_mtx(const struct lock_object *lock) 1255 { 1256 struct thread *td; 1257 const struct mtx *m; 1258 1259 m = (const struct mtx *)lock; 1260 1261 db_printf(" flags: {"); 1262 if (LOCK_CLASS(lock) == &lock_class_mtx_spin) 1263 db_printf("SPIN"); 1264 else 1265 db_printf("DEF"); 1266 if (m->lock_object.lo_flags & LO_RECURSABLE) 1267 db_printf(", RECURSE"); 1268 if (m->lock_object.lo_flags & LO_DUPOK) 1269 db_printf(", DUPOK"); 1270 db_printf("}\n"); 1271 db_printf(" state: {"); 1272 if (mtx_unowned(m)) 1273 db_printf("UNOWNED"); 1274 else if (mtx_destroyed(m)) 1275 db_printf("DESTROYED"); 1276 else { 1277 db_printf("OWNED"); 1278 if (m->mtx_lock & MTX_CONTESTED) 1279 db_printf(", CONTESTED"); 1280 if (m->mtx_lock & MTX_RECURSED) 1281 db_printf(", RECURSED"); 1282 } 1283 db_printf("}\n"); 1284 if (!mtx_unowned(m) && !mtx_destroyed(m)) { 1285 td = mtx_owner(m); 1286 db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td, 1287 td->td_tid, td->td_proc->p_pid, td->td_name); 1288 if (mtx_recursed(m)) 1289 db_printf(" recursed: %d\n", m->mtx_recurse); 1290 } 1291 } 1292 #endif
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