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 /* 180 * Treat LA_LOCKED as if LA_XLOCKED was asserted. 181 * 182 * Some callers of lc_assert uses LA_LOCKED to indicate that either 183 * a shared lock or write lock was held, while other callers uses 184 * the more strict LA_XLOCKED (used as MA_OWNED). 185 * 186 * Mutex is the only lock class that can not be shared, as a result, 187 * we can reasonably consider the caller really intends to assert 188 * LA_XLOCKED when they are asserting LA_LOCKED on a mutex object. 189 */ 190 if (what & LA_LOCKED) { 191 what &= ~LA_LOCKED; 192 what |= LA_XLOCKED; 193 } 194 mtx_assert((const struct mtx *)lock, what); 195 } 196 197 void 198 lock_mtx(struct lock_object *lock, uintptr_t how) 199 { 200 201 mtx_lock((struct mtx *)lock); 202 } 203 204 void 205 lock_spin(struct lock_object *lock, uintptr_t how) 206 { 207 208 panic("spin locks can only use msleep_spin"); 209 } 210 211 uintptr_t 212 unlock_mtx(struct lock_object *lock) 213 { 214 struct mtx *m; 215 216 m = (struct mtx *)lock; 217 mtx_assert(m, MA_OWNED | MA_NOTRECURSED); 218 mtx_unlock(m); 219 return (0); 220 } 221 222 uintptr_t 223 unlock_spin(struct lock_object *lock) 224 { 225 226 panic("spin locks can only use msleep_spin"); 227 } 228 229 #ifdef KDTRACE_HOOKS 230 int 231 owner_mtx(const struct lock_object *lock, struct thread **owner) 232 { 233 const struct mtx *m; 234 uintptr_t x; 235 236 m = (const struct mtx *)lock; 237 x = m->mtx_lock; 238 *owner = (struct thread *)(x & ~MTX_FLAGMASK); 239 return (*owner != NULL); 240 } 241 #endif 242 243 /* 244 * Function versions of the inlined __mtx_* macros. These are used by 245 * modules and can also be called from assembly language if needed. 246 */ 247 void 248 __mtx_lock_flags(volatile uintptr_t *c, int opts, const char *file, int line) 249 { 250 struct mtx *m; 251 uintptr_t tid, v; 252 253 m = mtxlock2mtx(c); 254 255 KASSERT(kdb_active != 0 || SCHEDULER_STOPPED() || 256 !TD_IS_IDLETHREAD(curthread), 257 ("mtx_lock() by idle thread %p on sleep mutex %s @ %s:%d", 258 curthread, m->lock_object.lo_name, file, line)); 259 KASSERT(m->mtx_lock != MTX_DESTROYED, 260 ("mtx_lock() of destroyed mutex @ %s:%d", file, line)); 261 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, 262 ("mtx_lock() of spin mutex %s @ %s:%d", m->lock_object.lo_name, 263 file, line)); 264 WITNESS_CHECKORDER(&m->lock_object, (opts & ~MTX_RECURSE) | 265 LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); 266 267 tid = (uintptr_t)curthread; 268 v = MTX_UNOWNED; 269 if (!_mtx_obtain_lock_fetch(m, &v, tid)) 270 _mtx_lock_sleep(m, v, opts, file, line); 271 else 272 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire, 273 m, 0, 0, file, line); 274 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, 275 line); 276 WITNESS_LOCK(&m->lock_object, (opts & ~MTX_RECURSE) | LOP_EXCLUSIVE, 277 file, line); 278 TD_LOCKS_INC(curthread); 279 } 280 281 void 282 __mtx_unlock_flags(volatile uintptr_t *c, int opts, const char *file, int line) 283 { 284 struct mtx *m; 285 286 m = mtxlock2mtx(c); 287 288 KASSERT(m->mtx_lock != MTX_DESTROYED, 289 ("mtx_unlock() of destroyed mutex @ %s:%d", file, line)); 290 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, 291 ("mtx_unlock() of spin mutex %s @ %s:%d", m->lock_object.lo_name, 292 file, line)); 293 WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 294 LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file, 295 line); 296 mtx_assert(m, MA_OWNED); 297 298 #ifdef LOCK_PROFILING 299 __mtx_unlock_sleep(c, (uintptr_t)curthread, opts, file, line); 300 #else 301 __mtx_unlock(m, curthread, opts, file, line); 302 #endif 303 TD_LOCKS_DEC(curthread); 304 } 305 306 void 307 __mtx_lock_spin_flags(volatile uintptr_t *c, int opts, const char *file, 308 int line) 309 { 310 struct mtx *m; 311 #ifdef SMP 312 uintptr_t tid, v; 313 #endif 314 315 m = mtxlock2mtx(c); 316 317 KASSERT(m->mtx_lock != MTX_DESTROYED, 318 ("mtx_lock_spin() of destroyed mutex @ %s:%d", file, line)); 319 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 320 ("mtx_lock_spin() of sleep mutex %s @ %s:%d", 321 m->lock_object.lo_name, file, line)); 322 if (mtx_owned(m)) 323 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0 || 324 (opts & MTX_RECURSE) != 0, 325 ("mtx_lock_spin: recursed on non-recursive mutex %s @ %s:%d\n", 326 m->lock_object.lo_name, file, line)); 327 opts &= ~MTX_RECURSE; 328 WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE, 329 file, line, NULL); 330 #ifdef SMP 331 spinlock_enter(); 332 tid = (uintptr_t)curthread; 333 v = MTX_UNOWNED; 334 if (!_mtx_obtain_lock_fetch(m, &v, tid)) 335 _mtx_lock_spin(m, v, opts, file, line); 336 else 337 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, 338 m, 0, 0, file, line); 339 #else 340 __mtx_lock_spin(m, curthread, opts, file, line); 341 #endif 342 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, 343 line); 344 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 345 } 346 347 int 348 __mtx_trylock_spin_flags(volatile uintptr_t *c, int opts, const char *file, 349 int line) 350 { 351 struct mtx *m; 352 353 if (SCHEDULER_STOPPED()) 354 return (1); 355 356 m = mtxlock2mtx(c); 357 358 KASSERT(m->mtx_lock != MTX_DESTROYED, 359 ("mtx_trylock_spin() of destroyed mutex @ %s:%d", file, line)); 360 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 361 ("mtx_trylock_spin() of sleep mutex %s @ %s:%d", 362 m->lock_object.lo_name, file, line)); 363 KASSERT((opts & MTX_RECURSE) == 0, 364 ("mtx_trylock_spin: unsupp. opt MTX_RECURSE on mutex %s @ %s:%d\n", 365 m->lock_object.lo_name, file, line)); 366 if (__mtx_trylock_spin(m, curthread, opts, file, line)) { 367 LOCK_LOG_TRY("LOCK", &m->lock_object, opts, 1, file, line); 368 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 369 return (1); 370 } 371 LOCK_LOG_TRY("LOCK", &m->lock_object, opts, 0, file, line); 372 return (0); 373 } 374 375 void 376 __mtx_unlock_spin_flags(volatile uintptr_t *c, int opts, const char *file, 377 int line) 378 { 379 struct mtx *m; 380 381 m = mtxlock2mtx(c); 382 383 KASSERT(m->mtx_lock != MTX_DESTROYED, 384 ("mtx_unlock_spin() of destroyed mutex @ %s:%d", file, line)); 385 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 386 ("mtx_unlock_spin() of sleep mutex %s @ %s:%d", 387 m->lock_object.lo_name, file, line)); 388 WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 389 LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file, 390 line); 391 mtx_assert(m, MA_OWNED); 392 393 __mtx_unlock_spin(m); 394 } 395 396 /* 397 * The important part of mtx_trylock{,_flags}() 398 * Tries to acquire lock `m.' If this function is called on a mutex that 399 * is already owned, it will recursively acquire the lock. 400 */ 401 int 402 _mtx_trylock_flags_int(struct mtx *m, int opts LOCK_FILE_LINE_ARG_DEF) 403 { 404 struct thread *td; 405 uintptr_t tid, v; 406 #ifdef LOCK_PROFILING 407 uint64_t waittime = 0; 408 int contested = 0; 409 #endif 410 int rval; 411 bool recursed; 412 413 td = curthread; 414 tid = (uintptr_t)td; 415 if (SCHEDULER_STOPPED_TD(td)) 416 return (1); 417 418 KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(td), 419 ("mtx_trylock() by idle thread %p on sleep mutex %s @ %s:%d", 420 curthread, m->lock_object.lo_name, file, line)); 421 KASSERT(m->mtx_lock != MTX_DESTROYED, 422 ("mtx_trylock() of destroyed mutex @ %s:%d", file, line)); 423 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep, 424 ("mtx_trylock() of spin mutex %s @ %s:%d", m->lock_object.lo_name, 425 file, line)); 426 427 rval = 1; 428 recursed = false; 429 v = MTX_UNOWNED; 430 for (;;) { 431 if (_mtx_obtain_lock_fetch(m, &v, tid)) 432 break; 433 if (v == MTX_UNOWNED) 434 continue; 435 if (v == tid && 436 ((m->lock_object.lo_flags & LO_RECURSABLE) != 0 || 437 (opts & MTX_RECURSE) != 0)) { 438 m->mtx_recurse++; 439 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); 440 recursed = true; 441 break; 442 } 443 rval = 0; 444 break; 445 } 446 447 opts &= ~MTX_RECURSE; 448 449 LOCK_LOG_TRY("LOCK", &m->lock_object, opts, rval, file, line); 450 if (rval) { 451 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK, 452 file, line); 453 TD_LOCKS_INC(curthread); 454 if (!recursed) 455 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire, 456 m, contested, waittime, file, line); 457 } 458 459 return (rval); 460 } 461 462 int 463 _mtx_trylock_flags_(volatile uintptr_t *c, int opts, const char *file, int line) 464 { 465 struct mtx *m; 466 467 m = mtxlock2mtx(c); 468 return (_mtx_trylock_flags_int(m, opts LOCK_FILE_LINE_ARG)); 469 } 470 471 /* 472 * __mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock. 473 * 474 * We call this if the lock is either contested (i.e. we need to go to 475 * sleep waiting for it), or if we need to recurse on it. 476 */ 477 #if LOCK_DEBUG > 0 478 void 479 __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v, int opts, const char *file, 480 int line) 481 #else 482 void 483 __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v) 484 #endif 485 { 486 struct thread *td; 487 struct mtx *m; 488 struct turnstile *ts; 489 uintptr_t tid; 490 struct thread *owner; 491 #ifdef LOCK_PROFILING 492 int contested = 0; 493 uint64_t waittime = 0; 494 #endif 495 #if defined(ADAPTIVE_MUTEXES) || defined(KDTRACE_HOOKS) 496 struct lock_delay_arg lda; 497 #endif 498 #ifdef KDTRACE_HOOKS 499 u_int sleep_cnt = 0; 500 int64_t sleep_time = 0; 501 int64_t all_time = 0; 502 #endif 503 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 504 int doing_lockprof = 0; 505 #endif 506 507 td = curthread; 508 tid = (uintptr_t)td; 509 m = mtxlock2mtx(c); 510 511 #ifdef KDTRACE_HOOKS 512 if (LOCKSTAT_PROFILE_ENABLED(adaptive__acquire)) { 513 while (v == MTX_UNOWNED) { 514 if (_mtx_obtain_lock_fetch(m, &v, tid)) 515 goto out_lockstat; 516 } 517 doing_lockprof = 1; 518 all_time -= lockstat_nsecs(&m->lock_object); 519 } 520 #endif 521 #ifdef LOCK_PROFILING 522 doing_lockprof = 1; 523 #endif 524 525 if (SCHEDULER_STOPPED_TD(td)) 526 return; 527 528 #if defined(ADAPTIVE_MUTEXES) 529 lock_delay_arg_init(&lda, &mtx_delay); 530 #elif defined(KDTRACE_HOOKS) 531 lock_delay_arg_init(&lda, NULL); 532 #endif 533 534 if (__predict_false(v == MTX_UNOWNED)) 535 v = MTX_READ_VALUE(m); 536 537 if (__predict_false(lv_mtx_owner(v) == td)) { 538 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0 || 539 (opts & MTX_RECURSE) != 0, 540 ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n", 541 m->lock_object.lo_name, file, line)); 542 #if LOCK_DEBUG > 0 543 opts &= ~MTX_RECURSE; 544 #endif 545 m->mtx_recurse++; 546 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); 547 if (LOCK_LOG_TEST(&m->lock_object, opts)) 548 CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m); 549 return; 550 } 551 #if LOCK_DEBUG > 0 552 opts &= ~MTX_RECURSE; 553 #endif 554 555 #ifdef HWPMC_HOOKS 556 PMC_SOFT_CALL( , , lock, failed); 557 #endif 558 lock_profile_obtain_lock_failed(&m->lock_object, 559 &contested, &waittime); 560 if (LOCK_LOG_TEST(&m->lock_object, opts)) 561 CTR4(KTR_LOCK, 562 "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d", 563 m->lock_object.lo_name, (void *)m->mtx_lock, file, line); 564 565 for (;;) { 566 if (v == MTX_UNOWNED) { 567 if (_mtx_obtain_lock_fetch(m, &v, tid)) 568 break; 569 continue; 570 } 571 #ifdef KDTRACE_HOOKS 572 lda.spin_cnt++; 573 #endif 574 #ifdef ADAPTIVE_MUTEXES 575 /* 576 * If the owner is running on another CPU, spin until the 577 * owner stops running or the state of the lock changes. 578 */ 579 owner = lv_mtx_owner(v); 580 if (TD_IS_RUNNING(owner)) { 581 if (LOCK_LOG_TEST(&m->lock_object, 0)) 582 CTR3(KTR_LOCK, 583 "%s: spinning on %p held by %p", 584 __func__, m, owner); 585 KTR_STATE1(KTR_SCHED, "thread", 586 sched_tdname((struct thread *)tid), 587 "spinning", "lockname:\"%s\"", 588 m->lock_object.lo_name); 589 do { 590 lock_delay(&lda); 591 v = MTX_READ_VALUE(m); 592 owner = lv_mtx_owner(v); 593 } while (v != MTX_UNOWNED && TD_IS_RUNNING(owner)); 594 KTR_STATE0(KTR_SCHED, "thread", 595 sched_tdname((struct thread *)tid), 596 "running"); 597 continue; 598 } 599 #endif 600 601 ts = turnstile_trywait(&m->lock_object); 602 v = MTX_READ_VALUE(m); 603 retry_turnstile: 604 605 /* 606 * Check if the lock has been released while spinning for 607 * the turnstile chain lock. 608 */ 609 if (v == MTX_UNOWNED) { 610 turnstile_cancel(ts); 611 continue; 612 } 613 614 #ifdef ADAPTIVE_MUTEXES 615 /* 616 * The current lock owner might have started executing 617 * on another CPU (or the lock could have changed 618 * owners) while we were waiting on the turnstile 619 * chain lock. If so, drop the turnstile lock and try 620 * again. 621 */ 622 owner = lv_mtx_owner(v); 623 if (TD_IS_RUNNING(owner)) { 624 turnstile_cancel(ts); 625 continue; 626 } 627 #endif 628 629 /* 630 * If the mutex isn't already contested and a failure occurs 631 * setting the contested bit, the mutex was either released 632 * or the state of the MTX_RECURSED bit changed. 633 */ 634 if ((v & MTX_CONTESTED) == 0 && 635 !atomic_fcmpset_ptr(&m->mtx_lock, &v, v | MTX_CONTESTED)) { 636 goto retry_turnstile; 637 } 638 639 /* 640 * We definitely must sleep for this lock. 641 */ 642 mtx_assert(m, MA_NOTOWNED); 643 644 /* 645 * Block on the turnstile. 646 */ 647 #ifdef KDTRACE_HOOKS 648 sleep_time -= lockstat_nsecs(&m->lock_object); 649 #endif 650 #ifndef ADAPTIVE_MUTEXES 651 owner = mtx_owner(m); 652 #endif 653 MPASS(owner == mtx_owner(m)); 654 turnstile_wait(ts, owner, TS_EXCLUSIVE_QUEUE); 655 #ifdef KDTRACE_HOOKS 656 sleep_time += lockstat_nsecs(&m->lock_object); 657 sleep_cnt++; 658 #endif 659 v = MTX_READ_VALUE(m); 660 } 661 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 662 if (__predict_true(!doing_lockprof)) 663 return; 664 #endif 665 #ifdef KDTRACE_HOOKS 666 all_time += lockstat_nsecs(&m->lock_object); 667 if (sleep_time) 668 LOCKSTAT_RECORD1(adaptive__block, m, sleep_time); 669 670 /* 671 * Only record the loops spinning and not sleeping. 672 */ 673 if (lda.spin_cnt > sleep_cnt) 674 LOCKSTAT_RECORD1(adaptive__spin, m, all_time - sleep_time); 675 out_lockstat: 676 #endif 677 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire, m, contested, 678 waittime, file, line); 679 } 680 681 #ifdef SMP 682 /* 683 * _mtx_lock_spin_cookie: the tougher part of acquiring an MTX_SPIN lock. 684 * 685 * This is only called if we need to actually spin for the lock. Recursion 686 * is handled inline. 687 */ 688 #if LOCK_DEBUG > 0 689 void 690 _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v, int opts, 691 const char *file, int line) 692 #else 693 void 694 _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v) 695 #endif 696 { 697 struct mtx *m; 698 struct lock_delay_arg lda; 699 uintptr_t tid; 700 #ifdef LOCK_PROFILING 701 int contested = 0; 702 uint64_t waittime = 0; 703 #endif 704 #ifdef KDTRACE_HOOKS 705 int64_t spin_time = 0; 706 #endif 707 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 708 int doing_lockprof = 0; 709 #endif 710 711 tid = (uintptr_t)curthread; 712 m = mtxlock2mtx(c); 713 714 #ifdef KDTRACE_HOOKS 715 if (LOCKSTAT_PROFILE_ENABLED(adaptive__acquire)) { 716 while (v == MTX_UNOWNED) { 717 if (_mtx_obtain_lock_fetch(m, &v, tid)) 718 goto out_lockstat; 719 } 720 doing_lockprof = 1; 721 spin_time -= lockstat_nsecs(&m->lock_object); 722 } 723 #endif 724 #ifdef LOCK_PROFILING 725 doing_lockprof = 1; 726 #endif 727 728 if (__predict_false(v == MTX_UNOWNED)) 729 v = MTX_READ_VALUE(m); 730 731 if (__predict_false(v == tid)) { 732 m->mtx_recurse++; 733 return; 734 } 735 736 if (SCHEDULER_STOPPED()) 737 return; 738 739 lock_delay_arg_init(&lda, &mtx_spin_delay); 740 741 if (LOCK_LOG_TEST(&m->lock_object, opts)) 742 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m); 743 KTR_STATE1(KTR_SCHED, "thread", sched_tdname((struct thread *)tid), 744 "spinning", "lockname:\"%s\"", m->lock_object.lo_name); 745 746 #ifdef HWPMC_HOOKS 747 PMC_SOFT_CALL( , , lock, failed); 748 #endif 749 lock_profile_obtain_lock_failed(&m->lock_object, &contested, &waittime); 750 751 for (;;) { 752 if (v == MTX_UNOWNED) { 753 if (_mtx_obtain_lock_fetch(m, &v, tid)) 754 break; 755 continue; 756 } 757 /* Give interrupts a chance while we spin. */ 758 spinlock_exit(); 759 do { 760 if (__predict_true(lda.spin_cnt < 10000000)) { 761 lock_delay(&lda); 762 } else { 763 _mtx_lock_indefinite_check(m, &lda); 764 } 765 v = MTX_READ_VALUE(m); 766 } while (v != MTX_UNOWNED); 767 spinlock_enter(); 768 } 769 770 if (LOCK_LOG_TEST(&m->lock_object, opts)) 771 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m); 772 KTR_STATE0(KTR_SCHED, "thread", sched_tdname((struct thread *)tid), 773 "running"); 774 775 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 776 if (__predict_true(!doing_lockprof)) 777 return; 778 #endif 779 #ifdef KDTRACE_HOOKS 780 spin_time += lockstat_nsecs(&m->lock_object); 781 if (lda.spin_cnt != 0) 782 LOCKSTAT_RECORD1(spin__spin, m, spin_time); 783 out_lockstat: 784 #endif 785 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, m, 786 contested, waittime, file, line); 787 } 788 #endif /* SMP */ 789 790 #ifdef INVARIANTS 791 static void 792 thread_lock_validate(struct mtx *m, int opts, const char *file, int line) 793 { 794 795 KASSERT(m->mtx_lock != MTX_DESTROYED, 796 ("thread_lock() of destroyed mutex @ %s:%d", file, line)); 797 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 798 ("thread_lock() of sleep mutex %s @ %s:%d", 799 m->lock_object.lo_name, file, line)); 800 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) == 0, 801 ("thread_lock: got a recursive mutex %s @ %s:%d\n", 802 m->lock_object.lo_name, file, line)); 803 WITNESS_CHECKORDER(&m->lock_object, 804 opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); 805 } 806 #else 807 #define thread_lock_validate(m, opts, file, line) do { } while (0) 808 #endif 809 810 #ifndef LOCK_PROFILING 811 #if LOCK_DEBUG > 0 812 void 813 _thread_lock(struct thread *td, int opts, const char *file, int line) 814 #else 815 void 816 _thread_lock(struct thread *td) 817 #endif 818 { 819 struct mtx *m; 820 uintptr_t tid; 821 822 tid = (uintptr_t)curthread; 823 824 if (__predict_false(LOCKSTAT_PROFILE_ENABLED(spin__acquire))) 825 goto slowpath_noirq; 826 spinlock_enter(); 827 m = td->td_lock; 828 thread_lock_validate(m, 0, file, line); 829 if (__predict_false(m == &blocked_lock)) 830 goto slowpath_unlocked; 831 if (__predict_false(!_mtx_obtain_lock(m, tid))) 832 goto slowpath_unlocked; 833 if (__predict_true(m == td->td_lock)) { 834 WITNESS_LOCK(&m->lock_object, LOP_EXCLUSIVE, file, line); 835 return; 836 } 837 _mtx_release_lock_quick(m); 838 slowpath_unlocked: 839 spinlock_exit(); 840 slowpath_noirq: 841 #if LOCK_DEBUG > 0 842 thread_lock_flags_(td, opts, file, line); 843 #else 844 thread_lock_flags_(td, 0, 0, 0); 845 #endif 846 } 847 #endif 848 849 void 850 thread_lock_flags_(struct thread *td, int opts, const char *file, int line) 851 { 852 struct mtx *m; 853 uintptr_t tid, v; 854 struct lock_delay_arg lda; 855 #ifdef LOCK_PROFILING 856 int contested = 0; 857 uint64_t waittime = 0; 858 #endif 859 #ifdef KDTRACE_HOOKS 860 int64_t spin_time = 0; 861 #endif 862 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 863 int doing_lockprof = 1; 864 #endif 865 866 tid = (uintptr_t)curthread; 867 868 if (SCHEDULER_STOPPED()) { 869 /* 870 * Ensure that spinlock sections are balanced even when the 871 * scheduler is stopped, since we may otherwise inadvertently 872 * re-enable interrupts while dumping core. 873 */ 874 spinlock_enter(); 875 return; 876 } 877 878 lock_delay_arg_init(&lda, &mtx_spin_delay); 879 880 #ifdef HWPMC_HOOKS 881 PMC_SOFT_CALL( , , lock, failed); 882 #endif 883 884 #ifdef LOCK_PROFILING 885 doing_lockprof = 1; 886 #elif defined(KDTRACE_HOOKS) 887 doing_lockprof = lockstat_enabled; 888 if (__predict_false(doing_lockprof)) 889 spin_time -= lockstat_nsecs(&td->td_lock->lock_object); 890 #endif 891 spinlock_enter(); 892 893 for (;;) { 894 retry: 895 m = td->td_lock; 896 thread_lock_validate(m, opts, file, line); 897 v = MTX_READ_VALUE(m); 898 for (;;) { 899 if (v == MTX_UNOWNED) { 900 if (_mtx_obtain_lock_fetch(m, &v, tid)) 901 break; 902 continue; 903 } 904 MPASS(v != tid); 905 lock_profile_obtain_lock_failed(&m->lock_object, 906 &contested, &waittime); 907 /* Give interrupts a chance while we spin. */ 908 spinlock_exit(); 909 do { 910 if (__predict_true(lda.spin_cnt < 10000000)) { 911 lock_delay(&lda); 912 } else { 913 _mtx_lock_indefinite_check(m, &lda); 914 } 915 if (m != td->td_lock) { 916 spinlock_enter(); 917 goto retry; 918 } 919 v = MTX_READ_VALUE(m); 920 } while (v != MTX_UNOWNED); 921 spinlock_enter(); 922 } 923 if (m == td->td_lock) 924 break; 925 _mtx_release_lock_quick(m); 926 } 927 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, 928 line); 929 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 930 931 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 932 if (__predict_true(!doing_lockprof)) 933 return; 934 #endif 935 #ifdef KDTRACE_HOOKS 936 spin_time += lockstat_nsecs(&m->lock_object); 937 #endif 938 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, m, contested, 939 waittime, file, line); 940 #ifdef KDTRACE_HOOKS 941 if (lda.spin_cnt != 0) 942 LOCKSTAT_RECORD1(thread__spin, m, spin_time); 943 #endif 944 } 945 946 struct mtx * 947 thread_lock_block(struct thread *td) 948 { 949 struct mtx *lock; 950 951 lock = td->td_lock; 952 mtx_assert(lock, MA_OWNED); 953 td->td_lock = &blocked_lock; 954 955 return (lock); 956 } 957 958 void 959 thread_lock_unblock(struct thread *td, struct mtx *new) 960 { 961 962 mtx_assert(new, MA_OWNED); 963 KASSERT(td->td_lock == &blocked_lock, 964 ("thread %p lock %p not blocked_lock %p", 965 td, td->td_lock, &blocked_lock)); 966 atomic_store_rel_ptr((volatile void *)&td->td_lock, (uintptr_t)new); 967 } 968 969 void 970 thread_lock_block_wait(struct thread *td) 971 { 972 973 while (td->td_lock == &blocked_lock) 974 cpu_spinwait(); 975 976 /* Acquire fence to be certain that all thread state is visible. */ 977 atomic_thread_fence_acq(); 978 } 979 980 void 981 thread_lock_set(struct thread *td, struct mtx *new) 982 { 983 struct mtx *lock; 984 985 mtx_assert(new, MA_OWNED); 986 lock = td->td_lock; 987 mtx_assert(lock, MA_OWNED); 988 td->td_lock = new; 989 mtx_unlock_spin(lock); 990 } 991 992 /* 993 * __mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock. 994 * 995 * We are only called here if the lock is recursed, contested (i.e. we 996 * need to wake up a blocked thread) or lockstat probe is active. 997 */ 998 #if LOCK_DEBUG > 0 999 void 1000 __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v, int opts, 1001 const char *file, int line) 1002 #else 1003 void 1004 __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v) 1005 #endif 1006 { 1007 struct mtx *m; 1008 struct turnstile *ts; 1009 uintptr_t tid; 1010 1011 if (SCHEDULER_STOPPED()) 1012 return; 1013 1014 tid = (uintptr_t)curthread; 1015 m = mtxlock2mtx(c); 1016 1017 if (__predict_false(v == tid)) 1018 v = MTX_READ_VALUE(m); 1019 1020 if (__predict_false(v & MTX_RECURSED)) { 1021 if (--(m->mtx_recurse) == 0) 1022 atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED); 1023 if (LOCK_LOG_TEST(&m->lock_object, opts)) 1024 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m); 1025 return; 1026 } 1027 1028 LOCKSTAT_PROFILE_RELEASE_LOCK(adaptive__release, m); 1029 if (v == tid && _mtx_release_lock(m, tid)) 1030 return; 1031 1032 /* 1033 * We have to lock the chain before the turnstile so this turnstile 1034 * can be removed from the hash list if it is empty. 1035 */ 1036 turnstile_chain_lock(&m->lock_object); 1037 _mtx_release_lock_quick(m); 1038 ts = turnstile_lookup(&m->lock_object); 1039 MPASS(ts != NULL); 1040 if (LOCK_LOG_TEST(&m->lock_object, opts)) 1041 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m); 1042 turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE); 1043 1044 /* 1045 * This turnstile is now no longer associated with the mutex. We can 1046 * unlock the chain lock so a new turnstile may take it's place. 1047 */ 1048 turnstile_unpend(ts); 1049 turnstile_chain_unlock(&m->lock_object); 1050 } 1051 1052 /* 1053 * All the unlocking of MTX_SPIN locks is done inline. 1054 * See the __mtx_unlock_spin() macro for the details. 1055 */ 1056 1057 /* 1058 * The backing function for the INVARIANTS-enabled mtx_assert() 1059 */ 1060 #ifdef INVARIANT_SUPPORT 1061 void 1062 __mtx_assert(const volatile uintptr_t *c, int what, const char *file, int line) 1063 { 1064 const struct mtx *m; 1065 1066 if (panicstr != NULL || dumping || SCHEDULER_STOPPED()) 1067 return; 1068 1069 m = mtxlock2mtx(c); 1070 1071 switch (what) { 1072 case MA_OWNED: 1073 case MA_OWNED | MA_RECURSED: 1074 case MA_OWNED | MA_NOTRECURSED: 1075 if (!mtx_owned(m)) 1076 panic("mutex %s not owned at %s:%d", 1077 m->lock_object.lo_name, file, line); 1078 if (mtx_recursed(m)) { 1079 if ((what & MA_NOTRECURSED) != 0) 1080 panic("mutex %s recursed at %s:%d", 1081 m->lock_object.lo_name, file, line); 1082 } else if ((what & MA_RECURSED) != 0) { 1083 panic("mutex %s unrecursed at %s:%d", 1084 m->lock_object.lo_name, file, line); 1085 } 1086 break; 1087 case MA_NOTOWNED: 1088 if (mtx_owned(m)) 1089 panic("mutex %s owned at %s:%d", 1090 m->lock_object.lo_name, file, line); 1091 break; 1092 default: 1093 panic("unknown mtx_assert at %s:%d", file, line); 1094 } 1095 } 1096 #endif 1097 1098 /* 1099 * General init routine used by the MTX_SYSINIT() macro. 1100 */ 1101 void 1102 mtx_sysinit(void *arg) 1103 { 1104 struct mtx_args *margs = arg; 1105 1106 mtx_init((struct mtx *)margs->ma_mtx, margs->ma_desc, NULL, 1107 margs->ma_opts); 1108 } 1109 1110 /* 1111 * Mutex initialization routine; initialize lock `m' of type contained in 1112 * `opts' with options contained in `opts' and name `name.' The optional 1113 * lock type `type' is used as a general lock category name for use with 1114 * witness. 1115 */ 1116 void 1117 _mtx_init(volatile uintptr_t *c, const char *name, const char *type, int opts) 1118 { 1119 struct mtx *m; 1120 struct lock_class *class; 1121 int flags; 1122 1123 m = mtxlock2mtx(c); 1124 1125 MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE | 1126 MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE | MTX_NEW)) == 0); 1127 ASSERT_ATOMIC_LOAD_PTR(m->mtx_lock, 1128 ("%s: mtx_lock not aligned for %s: %p", __func__, name, 1129 &m->mtx_lock)); 1130 1131 /* Determine lock class and lock flags. */ 1132 if (opts & MTX_SPIN) 1133 class = &lock_class_mtx_spin; 1134 else 1135 class = &lock_class_mtx_sleep; 1136 flags = 0; 1137 if (opts & MTX_QUIET) 1138 flags |= LO_QUIET; 1139 if (opts & MTX_RECURSE) 1140 flags |= LO_RECURSABLE; 1141 if ((opts & MTX_NOWITNESS) == 0) 1142 flags |= LO_WITNESS; 1143 if (opts & MTX_DUPOK) 1144 flags |= LO_DUPOK; 1145 if (opts & MTX_NOPROFILE) 1146 flags |= LO_NOPROFILE; 1147 if (opts & MTX_NEW) 1148 flags |= LO_NEW; 1149 1150 /* Initialize mutex. */ 1151 lock_init(&m->lock_object, class, name, type, flags); 1152 1153 m->mtx_lock = MTX_UNOWNED; 1154 m->mtx_recurse = 0; 1155 } 1156 1157 /* 1158 * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be 1159 * passed in as a flag here because if the corresponding mtx_init() was 1160 * called with MTX_QUIET set, then it will already be set in the mutex's 1161 * flags. 1162 */ 1163 void 1164 _mtx_destroy(volatile uintptr_t *c) 1165 { 1166 struct mtx *m; 1167 1168 m = mtxlock2mtx(c); 1169 1170 if (!mtx_owned(m)) 1171 MPASS(mtx_unowned(m)); 1172 else { 1173 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0); 1174 1175 /* Perform the non-mtx related part of mtx_unlock_spin(). */ 1176 if (LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin) 1177 spinlock_exit(); 1178 else 1179 TD_LOCKS_DEC(curthread); 1180 1181 lock_profile_release_lock(&m->lock_object); 1182 /* Tell witness this isn't locked to make it happy. */ 1183 WITNESS_UNLOCK(&m->lock_object, LOP_EXCLUSIVE, __FILE__, 1184 __LINE__); 1185 } 1186 1187 m->mtx_lock = MTX_DESTROYED; 1188 lock_destroy(&m->lock_object); 1189 } 1190 1191 /* 1192 * Intialize the mutex code and system mutexes. This is called from the MD 1193 * startup code prior to mi_startup(). The per-CPU data space needs to be 1194 * setup before this is called. 1195 */ 1196 void 1197 mutex_init(void) 1198 { 1199 1200 /* Setup turnstiles so that sleep mutexes work. */ 1201 init_turnstiles(); 1202 1203 /* 1204 * Initialize mutexes. 1205 */ 1206 mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE); 1207 mtx_init(&blocked_lock, "blocked lock", NULL, MTX_SPIN); 1208 blocked_lock.mtx_lock = 0xdeadc0de; /* Always blocked. */ 1209 mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK); 1210 mtx_init(&proc0.p_slock, "process slock", NULL, MTX_SPIN); 1211 mtx_init(&proc0.p_statmtx, "pstatl", NULL, MTX_SPIN); 1212 mtx_init(&proc0.p_itimmtx, "pitiml", NULL, MTX_SPIN); 1213 mtx_init(&proc0.p_profmtx, "pprofl", NULL, MTX_SPIN); 1214 mtx_init(&devmtx, "cdev", NULL, MTX_DEF); 1215 mtx_lock(&Giant); 1216 } 1217 1218 static void __noinline 1219 _mtx_lock_indefinite_check(struct mtx *m, struct lock_delay_arg *ldap) 1220 { 1221 struct thread *td; 1222 1223 ldap->spin_cnt++; 1224 if (ldap->spin_cnt < 60000000 || kdb_active || panicstr != NULL) 1225 cpu_lock_delay(); 1226 else { 1227 td = mtx_owner(m); 1228 1229 /* If the mutex is unlocked, try again. */ 1230 if (td == NULL) 1231 return; 1232 1233 printf( "spin lock %p (%s) held by %p (tid %d) too long\n", 1234 m, m->lock_object.lo_name, td, td->td_tid); 1235 #ifdef WITNESS 1236 witness_display_spinlock(&m->lock_object, td, printf); 1237 #endif 1238 panic("spin lock held too long"); 1239 } 1240 cpu_spinwait(); 1241 } 1242 1243 void 1244 mtx_spin_wait_unlocked(struct mtx *m) 1245 { 1246 struct lock_delay_arg lda; 1247 1248 KASSERT(m->mtx_lock != MTX_DESTROYED, 1249 ("%s() of destroyed mutex %p", __func__, m)); 1250 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 1251 ("%s() of sleep mutex %p (%s)", __func__, m, 1252 m->lock_object.lo_name)); 1253 KASSERT(!mtx_owned(m), ("%s() waiting on myself on lock %p (%s)", __func__, m, 1254 m->lock_object.lo_name)); 1255 1256 lda.spin_cnt = 0; 1257 1258 while (atomic_load_acq_ptr(&m->mtx_lock) != MTX_UNOWNED) { 1259 if (__predict_true(lda.spin_cnt < 10000000)) { 1260 cpu_spinwait(); 1261 lda.spin_cnt++; 1262 } else { 1263 _mtx_lock_indefinite_check(m, &lda); 1264 } 1265 } 1266 } 1267 1268 #ifdef DDB 1269 void 1270 db_show_mtx(const struct lock_object *lock) 1271 { 1272 struct thread *td; 1273 const struct mtx *m; 1274 1275 m = (const struct mtx *)lock; 1276 1277 db_printf(" flags: {"); 1278 if (LOCK_CLASS(lock) == &lock_class_mtx_spin) 1279 db_printf("SPIN"); 1280 else 1281 db_printf("DEF"); 1282 if (m->lock_object.lo_flags & LO_RECURSABLE) 1283 db_printf(", RECURSE"); 1284 if (m->lock_object.lo_flags & LO_DUPOK) 1285 db_printf(", DUPOK"); 1286 db_printf("}\n"); 1287 db_printf(" state: {"); 1288 if (mtx_unowned(m)) 1289 db_printf("UNOWNED"); 1290 else if (mtx_destroyed(m)) 1291 db_printf("DESTROYED"); 1292 else { 1293 db_printf("OWNED"); 1294 if (m->mtx_lock & MTX_CONTESTED) 1295 db_printf(", CONTESTED"); 1296 if (m->mtx_lock & MTX_RECURSED) 1297 db_printf(", RECURSED"); 1298 } 1299 db_printf("}\n"); 1300 if (!mtx_unowned(m) && !mtx_destroyed(m)) { 1301 td = mtx_owner(m); 1302 db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td, 1303 td->td_tid, td->td_proc->p_pid, td->td_name); 1304 if (mtx_recursed(m)) 1305 db_printf(" recursed: %d\n", m->mtx_recurse); 1306 } 1307 } 1308 #endif 1309