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 td = curthread; 495 tid = (uintptr_t)td; 496 if (SCHEDULER_STOPPED_TD(td)) 497 return; 498 499 #if defined(ADAPTIVE_MUTEXES) 500 lock_delay_arg_init(&lda, &mtx_delay); 501 #elif defined(KDTRACE_HOOKS) 502 lock_delay_arg_init(&lda, NULL); 503 #endif 504 m = mtxlock2mtx(c); 505 if (__predict_false(v == MTX_UNOWNED)) 506 v = MTX_READ_VALUE(m); 507 508 if (__predict_false(lv_mtx_owner(v) == td)) { 509 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0 || 510 (opts & MTX_RECURSE) != 0, 511 ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n", 512 m->lock_object.lo_name, file, line)); 513 #if LOCK_DEBUG > 0 514 opts &= ~MTX_RECURSE; 515 #endif 516 m->mtx_recurse++; 517 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); 518 if (LOCK_LOG_TEST(&m->lock_object, opts)) 519 CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m); 520 return; 521 } 522 #if LOCK_DEBUG > 0 523 opts &= ~MTX_RECURSE; 524 #endif 525 526 #ifdef HWPMC_HOOKS 527 PMC_SOFT_CALL( , , lock, failed); 528 #endif 529 lock_profile_obtain_lock_failed(&m->lock_object, 530 &contested, &waittime); 531 if (LOCK_LOG_TEST(&m->lock_object, opts)) 532 CTR4(KTR_LOCK, 533 "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d", 534 m->lock_object.lo_name, (void *)m->mtx_lock, file, line); 535 #ifdef LOCK_PROFILING 536 doing_lockprof = 1; 537 #elif defined(KDTRACE_HOOKS) 538 doing_lockprof = lockstat_enabled; 539 if (__predict_false(doing_lockprof)) 540 all_time -= lockstat_nsecs(&m->lock_object); 541 #endif 542 543 for (;;) { 544 if (v == MTX_UNOWNED) { 545 if (_mtx_obtain_lock_fetch(m, &v, tid)) 546 break; 547 continue; 548 } 549 #ifdef KDTRACE_HOOKS 550 lda.spin_cnt++; 551 #endif 552 #ifdef ADAPTIVE_MUTEXES 553 /* 554 * If the owner is running on another CPU, spin until the 555 * owner stops running or the state of the lock changes. 556 */ 557 owner = lv_mtx_owner(v); 558 if (TD_IS_RUNNING(owner)) { 559 if (LOCK_LOG_TEST(&m->lock_object, 0)) 560 CTR3(KTR_LOCK, 561 "%s: spinning on %p held by %p", 562 __func__, m, owner); 563 KTR_STATE1(KTR_SCHED, "thread", 564 sched_tdname((struct thread *)tid), 565 "spinning", "lockname:\"%s\"", 566 m->lock_object.lo_name); 567 do { 568 lock_delay(&lda); 569 v = MTX_READ_VALUE(m); 570 owner = lv_mtx_owner(v); 571 } while (v != MTX_UNOWNED && TD_IS_RUNNING(owner)); 572 KTR_STATE0(KTR_SCHED, "thread", 573 sched_tdname((struct thread *)tid), 574 "running"); 575 continue; 576 } 577 #endif 578 579 ts = turnstile_trywait(&m->lock_object); 580 v = MTX_READ_VALUE(m); 581 582 /* 583 * Check if the lock has been released while spinning for 584 * the turnstile chain lock. 585 */ 586 if (v == MTX_UNOWNED) { 587 turnstile_cancel(ts); 588 continue; 589 } 590 591 #ifdef ADAPTIVE_MUTEXES 592 /* 593 * The current lock owner might have started executing 594 * on another CPU (or the lock could have changed 595 * owners) while we were waiting on the turnstile 596 * chain lock. If so, drop the turnstile lock and try 597 * again. 598 */ 599 owner = lv_mtx_owner(v); 600 if (TD_IS_RUNNING(owner)) { 601 turnstile_cancel(ts); 602 continue; 603 } 604 #endif 605 606 /* 607 * If the mutex isn't already contested and a failure occurs 608 * setting the contested bit, the mutex was either released 609 * or the state of the MTX_RECURSED bit changed. 610 */ 611 if ((v & MTX_CONTESTED) == 0 && 612 !atomic_cmpset_ptr(&m->mtx_lock, v, v | MTX_CONTESTED)) { 613 turnstile_cancel(ts); 614 v = MTX_READ_VALUE(m); 615 continue; 616 } 617 618 /* 619 * We definitely must sleep for this lock. 620 */ 621 mtx_assert(m, MA_NOTOWNED); 622 623 #ifdef KTR 624 if (!cont_logged) { 625 CTR6(KTR_CONTENTION, 626 "contention: %p at %s:%d wants %s, taken by %s:%d", 627 (void *)tid, file, line, m->lock_object.lo_name, 628 WITNESS_FILE(&m->lock_object), 629 WITNESS_LINE(&m->lock_object)); 630 cont_logged = 1; 631 } 632 #endif 633 634 /* 635 * Block on the turnstile. 636 */ 637 #ifdef KDTRACE_HOOKS 638 sleep_time -= lockstat_nsecs(&m->lock_object); 639 #endif 640 #ifndef ADAPTIVE_MUTEXES 641 owner = mtx_owner(m); 642 #endif 643 MPASS(owner == mtx_owner(m)); 644 turnstile_wait(ts, owner, TS_EXCLUSIVE_QUEUE); 645 #ifdef KDTRACE_HOOKS 646 sleep_time += lockstat_nsecs(&m->lock_object); 647 sleep_cnt++; 648 #endif 649 v = MTX_READ_VALUE(m); 650 } 651 #ifdef KTR 652 if (cont_logged) { 653 CTR4(KTR_CONTENTION, 654 "contention end: %s acquired by %p at %s:%d", 655 m->lock_object.lo_name, (void *)tid, file, line); 656 } 657 #endif 658 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 659 if (__predict_true(!doing_lockprof)) 660 return; 661 #endif 662 #ifdef KDTRACE_HOOKS 663 all_time += lockstat_nsecs(&m->lock_object); 664 #endif 665 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire, m, contested, 666 waittime, file, line); 667 #ifdef KDTRACE_HOOKS 668 if (sleep_time) 669 LOCKSTAT_RECORD1(adaptive__block, m, sleep_time); 670 671 /* 672 * Only record the loops spinning and not sleeping. 673 */ 674 if (lda.spin_cnt > sleep_cnt) 675 LOCKSTAT_RECORD1(adaptive__spin, m, all_time - sleep_time); 676 #endif 677 } 678 679 #ifdef SMP 680 /* 681 * _mtx_lock_spin_cookie: the tougher part of acquiring an MTX_SPIN lock. 682 * 683 * This is only called if we need to actually spin for the lock. Recursion 684 * is handled inline. 685 */ 686 #if LOCK_DEBUG > 0 687 void 688 _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v, int opts, 689 const char *file, int line) 690 #else 691 void 692 _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v) 693 #endif 694 { 695 struct mtx *m; 696 struct lock_delay_arg lda; 697 uintptr_t tid; 698 #ifdef LOCK_PROFILING 699 int contested = 0; 700 uint64_t waittime = 0; 701 #endif 702 #ifdef KDTRACE_HOOKS 703 int64_t spin_time = 0; 704 #endif 705 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 706 int doing_lockprof; 707 #endif 708 709 tid = (uintptr_t)curthread; 710 m = mtxlock2mtx(c); 711 712 if (__predict_false(v == MTX_UNOWNED)) 713 v = MTX_READ_VALUE(m); 714 715 if (__predict_false(v == tid)) { 716 m->mtx_recurse++; 717 return; 718 } 719 720 if (SCHEDULER_STOPPED()) 721 return; 722 723 lock_delay_arg_init(&lda, &mtx_spin_delay); 724 725 if (LOCK_LOG_TEST(&m->lock_object, opts)) 726 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m); 727 KTR_STATE1(KTR_SCHED, "thread", sched_tdname((struct thread *)tid), 728 "spinning", "lockname:\"%s\"", m->lock_object.lo_name); 729 730 #ifdef HWPMC_HOOKS 731 PMC_SOFT_CALL( , , lock, failed); 732 #endif 733 lock_profile_obtain_lock_failed(&m->lock_object, &contested, &waittime); 734 #ifdef LOCK_PROFILING 735 doing_lockprof = 1; 736 #elif defined(KDTRACE_HOOKS) 737 doing_lockprof = lockstat_enabled; 738 if (__predict_false(doing_lockprof)) 739 spin_time -= lockstat_nsecs(&m->lock_object); 740 #endif 741 for (;;) { 742 if (v == MTX_UNOWNED) { 743 if (_mtx_obtain_lock_fetch(m, &v, tid)) 744 break; 745 continue; 746 } 747 /* Give interrupts a chance while we spin. */ 748 spinlock_exit(); 749 do { 750 if (__predict_true(lda.spin_cnt < 10000000)) { 751 lock_delay(&lda); 752 } else { 753 _mtx_lock_indefinite_check(m, &lda); 754 } 755 v = MTX_READ_VALUE(m); 756 } while (v != MTX_UNOWNED); 757 spinlock_enter(); 758 } 759 760 if (LOCK_LOG_TEST(&m->lock_object, opts)) 761 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m); 762 KTR_STATE0(KTR_SCHED, "thread", sched_tdname((struct thread *)tid), 763 "running"); 764 765 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 766 if (__predict_true(!doing_lockprof)) 767 return; 768 #endif 769 #ifdef KDTRACE_HOOKS 770 spin_time += lockstat_nsecs(&m->lock_object); 771 #endif 772 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, m, 773 contested, waittime, file, line); 774 #ifdef KDTRACE_HOOKS 775 if (lda.spin_cnt != 0) 776 LOCKSTAT_RECORD1(spin__spin, m, spin_time); 777 #endif 778 } 779 #endif /* SMP */ 780 781 #ifdef INVARIANTS 782 static void 783 thread_lock_validate(struct mtx *m, int opts, const char *file, int line) 784 { 785 786 KASSERT(m->mtx_lock != MTX_DESTROYED, 787 ("thread_lock() of destroyed mutex @ %s:%d", file, line)); 788 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin, 789 ("thread_lock() of sleep mutex %s @ %s:%d", 790 m->lock_object.lo_name, file, line)); 791 if (mtx_owned(m)) 792 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0, 793 ("thread_lock: recursed on non-recursive mutex %s @ %s:%d\n", 794 m->lock_object.lo_name, file, line)); 795 WITNESS_CHECKORDER(&m->lock_object, 796 opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL); 797 } 798 #else 799 #define thread_lock_validate(m, opts, file, line) do { } while (0) 800 #endif 801 802 #ifndef LOCK_PROFILING 803 #if LOCK_DEBUG > 0 804 void 805 _thread_lock(struct thread *td, int opts, const char *file, int line) 806 #else 807 void 808 _thread_lock(struct thread *td) 809 #endif 810 { 811 struct mtx *m; 812 uintptr_t tid, v; 813 814 tid = (uintptr_t)curthread; 815 816 if (__predict_false(LOCKSTAT_PROFILE_ENABLED(spin__acquire))) 817 goto slowpath_noirq; 818 spinlock_enter(); 819 m = td->td_lock; 820 thread_lock_validate(m, 0, file, line); 821 v = MTX_READ_VALUE(m); 822 if (__predict_true(v == MTX_UNOWNED)) { 823 if (__predict_false(!_mtx_obtain_lock(m, tid))) 824 goto slowpath_unlocked; 825 } else if (v == tid) { 826 m->mtx_recurse++; 827 } else 828 goto slowpath_unlocked; 829 if (__predict_true(m == td->td_lock)) { 830 WITNESS_LOCK(&m->lock_object, LOP_EXCLUSIVE, file, line); 831 return; 832 } 833 if (m->mtx_recurse != 0) 834 m->mtx_recurse--; 835 else 836 _mtx_release_lock_quick(m); 837 slowpath_unlocked: 838 spinlock_exit(); 839 slowpath_noirq: 840 #if LOCK_DEBUG > 0 841 thread_lock_flags_(td, opts, file, line); 842 #else 843 thread_lock_flags_(td, 0, 0, 0); 844 #endif 845 } 846 #endif 847 848 void 849 thread_lock_flags_(struct thread *td, int opts, const char *file, int line) 850 { 851 struct mtx *m; 852 uintptr_t tid, v; 853 struct lock_delay_arg lda; 854 #ifdef LOCK_PROFILING 855 int contested = 0; 856 uint64_t waittime = 0; 857 #endif 858 #ifdef KDTRACE_HOOKS 859 int64_t spin_time = 0; 860 #endif 861 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 862 int doing_lockprof = 1; 863 #endif 864 865 tid = (uintptr_t)curthread; 866 867 if (SCHEDULER_STOPPED()) { 868 /* 869 * Ensure that spinlock sections are balanced even when the 870 * scheduler is stopped, since we may otherwise inadvertently 871 * re-enable interrupts while dumping core. 872 */ 873 spinlock_enter(); 874 return; 875 } 876 877 lock_delay_arg_init(&lda, &mtx_spin_delay); 878 879 #ifdef HWPMC_HOOKS 880 PMC_SOFT_CALL( , , lock, failed); 881 #endif 882 883 #ifdef LOCK_PROFILING 884 doing_lockprof = 1; 885 #elif defined(KDTRACE_HOOKS) 886 doing_lockprof = lockstat_enabled; 887 if (__predict_false(doing_lockprof)) 888 spin_time -= lockstat_nsecs(&td->td_lock->lock_object); 889 #endif 890 for (;;) { 891 retry: 892 spinlock_enter(); 893 m = td->td_lock; 894 thread_lock_validate(m, opts, file, line); 895 v = MTX_READ_VALUE(m); 896 for (;;) { 897 if (v == MTX_UNOWNED) { 898 if (_mtx_obtain_lock_fetch(m, &v, tid)) 899 break; 900 continue; 901 } 902 if (v == tid) { 903 m->mtx_recurse++; 904 break; 905 } 906 lock_profile_obtain_lock_failed(&m->lock_object, 907 &contested, &waittime); 908 /* Give interrupts a chance while we spin. */ 909 spinlock_exit(); 910 do { 911 if (__predict_true(lda.spin_cnt < 10000000)) { 912 lock_delay(&lda); 913 } else { 914 _mtx_lock_indefinite_check(m, &lda); 915 } 916 if (m != td->td_lock) 917 goto retry; 918 v = MTX_READ_VALUE(m); 919 } while (v != MTX_UNOWNED); 920 spinlock_enter(); 921 } 922 if (m == td->td_lock) 923 break; 924 __mtx_unlock_spin(m); /* does spinlock_exit() */ 925 } 926 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file, 927 line); 928 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line); 929 930 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING) 931 if (__predict_true(!doing_lockprof)) 932 return; 933 #endif 934 #ifdef KDTRACE_HOOKS 935 spin_time += lockstat_nsecs(&m->lock_object); 936 #endif 937 if (m->mtx_recurse == 0) 938 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, m, 939 contested, 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 THREAD_LOCK_ASSERT(td, MA_OWNED); 952 lock = td->td_lock; 953 td->td_lock = &blocked_lock; 954 mtx_unlock_spin(lock); 955 956 return (lock); 957 } 958 959 void 960 thread_lock_unblock(struct thread *td, struct mtx *new) 961 { 962 mtx_assert(new, MA_OWNED); 963 MPASS(td->td_lock == &blocked_lock); 964 atomic_store_rel_ptr((volatile void *)&td->td_lock, (uintptr_t)new); 965 } 966 967 void 968 thread_lock_set(struct thread *td, struct mtx *new) 969 { 970 struct mtx *lock; 971 972 mtx_assert(new, MA_OWNED); 973 THREAD_LOCK_ASSERT(td, MA_OWNED); 974 lock = td->td_lock; 975 td->td_lock = new; 976 mtx_unlock_spin(lock); 977 } 978 979 /* 980 * __mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock. 981 * 982 * We are only called here if the lock is recursed, contested (i.e. we 983 * need to wake up a blocked thread) or lockstat probe is active. 984 */ 985 #if LOCK_DEBUG > 0 986 void 987 __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v, int opts, 988 const char *file, int line) 989 #else 990 void 991 __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v) 992 #endif 993 { 994 struct mtx *m; 995 struct turnstile *ts; 996 uintptr_t tid; 997 998 if (SCHEDULER_STOPPED()) 999 return; 1000 1001 tid = (uintptr_t)curthread; 1002 m = mtxlock2mtx(c); 1003 1004 if (__predict_false(v == tid)) 1005 v = MTX_READ_VALUE(m); 1006 1007 if (__predict_false(v & MTX_RECURSED)) { 1008 if (--(m->mtx_recurse) == 0) 1009 atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED); 1010 if (LOCK_LOG_TEST(&m->lock_object, opts)) 1011 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m); 1012 return; 1013 } 1014 1015 LOCKSTAT_PROFILE_RELEASE_LOCK(adaptive__release, m); 1016 if (v == tid && _mtx_release_lock(m, tid)) 1017 return; 1018 1019 /* 1020 * We have to lock the chain before the turnstile so this turnstile 1021 * can be removed from the hash list if it is empty. 1022 */ 1023 turnstile_chain_lock(&m->lock_object); 1024 _mtx_release_lock_quick(m); 1025 ts = turnstile_lookup(&m->lock_object); 1026 MPASS(ts != NULL); 1027 if (LOCK_LOG_TEST(&m->lock_object, opts)) 1028 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m); 1029 turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE); 1030 1031 /* 1032 * This turnstile is now no longer associated with the mutex. We can 1033 * unlock the chain lock so a new turnstile may take it's place. 1034 */ 1035 turnstile_unpend(ts, TS_EXCLUSIVE_LOCK); 1036 turnstile_chain_unlock(&m->lock_object); 1037 } 1038 1039 /* 1040 * All the unlocking of MTX_SPIN locks is done inline. 1041 * See the __mtx_unlock_spin() macro for the details. 1042 */ 1043 1044 /* 1045 * The backing function for the INVARIANTS-enabled mtx_assert() 1046 */ 1047 #ifdef INVARIANT_SUPPORT 1048 void 1049 __mtx_assert(const volatile uintptr_t *c, int what, const char *file, int line) 1050 { 1051 const struct mtx *m; 1052 1053 if (panicstr != NULL || dumping || SCHEDULER_STOPPED()) 1054 return; 1055 1056 m = mtxlock2mtx(c); 1057 1058 switch (what) { 1059 case MA_OWNED: 1060 case MA_OWNED | MA_RECURSED: 1061 case MA_OWNED | MA_NOTRECURSED: 1062 if (!mtx_owned(m)) 1063 panic("mutex %s not owned at %s:%d", 1064 m->lock_object.lo_name, file, line); 1065 if (mtx_recursed(m)) { 1066 if ((what & MA_NOTRECURSED) != 0) 1067 panic("mutex %s recursed at %s:%d", 1068 m->lock_object.lo_name, file, line); 1069 } else if ((what & MA_RECURSED) != 0) { 1070 panic("mutex %s unrecursed at %s:%d", 1071 m->lock_object.lo_name, file, line); 1072 } 1073 break; 1074 case MA_NOTOWNED: 1075 if (mtx_owned(m)) 1076 panic("mutex %s owned at %s:%d", 1077 m->lock_object.lo_name, file, line); 1078 break; 1079 default: 1080 panic("unknown mtx_assert at %s:%d", file, line); 1081 } 1082 } 1083 #endif 1084 1085 /* 1086 * General init routine used by the MTX_SYSINIT() macro. 1087 */ 1088 void 1089 mtx_sysinit(void *arg) 1090 { 1091 struct mtx_args *margs = arg; 1092 1093 mtx_init((struct mtx *)margs->ma_mtx, margs->ma_desc, NULL, 1094 margs->ma_opts); 1095 } 1096 1097 /* 1098 * Mutex initialization routine; initialize lock `m' of type contained in 1099 * `opts' with options contained in `opts' and name `name.' The optional 1100 * lock type `type' is used as a general lock category name for use with 1101 * witness. 1102 */ 1103 void 1104 _mtx_init(volatile uintptr_t *c, const char *name, const char *type, int opts) 1105 { 1106 struct mtx *m; 1107 struct lock_class *class; 1108 int flags; 1109 1110 m = mtxlock2mtx(c); 1111 1112 MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE | 1113 MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE | MTX_NEW)) == 0); 1114 ASSERT_ATOMIC_LOAD_PTR(m->mtx_lock, 1115 ("%s: mtx_lock not aligned for %s: %p", __func__, name, 1116 &m->mtx_lock)); 1117 1118 /* Determine lock class and lock flags. */ 1119 if (opts & MTX_SPIN) 1120 class = &lock_class_mtx_spin; 1121 else 1122 class = &lock_class_mtx_sleep; 1123 flags = 0; 1124 if (opts & MTX_QUIET) 1125 flags |= LO_QUIET; 1126 if (opts & MTX_RECURSE) 1127 flags |= LO_RECURSABLE; 1128 if ((opts & MTX_NOWITNESS) == 0) 1129 flags |= LO_WITNESS; 1130 if (opts & MTX_DUPOK) 1131 flags |= LO_DUPOK; 1132 if (opts & MTX_NOPROFILE) 1133 flags |= LO_NOPROFILE; 1134 if (opts & MTX_NEW) 1135 flags |= LO_NEW; 1136 1137 /* Initialize mutex. */ 1138 lock_init(&m->lock_object, class, name, type, flags); 1139 1140 m->mtx_lock = MTX_UNOWNED; 1141 m->mtx_recurse = 0; 1142 } 1143 1144 /* 1145 * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be 1146 * passed in as a flag here because if the corresponding mtx_init() was 1147 * called with MTX_QUIET set, then it will already be set in the mutex's 1148 * flags. 1149 */ 1150 void 1151 _mtx_destroy(volatile uintptr_t *c) 1152 { 1153 struct mtx *m; 1154 1155 m = mtxlock2mtx(c); 1156 1157 if (!mtx_owned(m)) 1158 MPASS(mtx_unowned(m)); 1159 else { 1160 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0); 1161 1162 /* Perform the non-mtx related part of mtx_unlock_spin(). */ 1163 if (LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin) 1164 spinlock_exit(); 1165 else 1166 TD_LOCKS_DEC(curthread); 1167 1168 lock_profile_release_lock(&m->lock_object); 1169 /* Tell witness this isn't locked to make it happy. */ 1170 WITNESS_UNLOCK(&m->lock_object, LOP_EXCLUSIVE, __FILE__, 1171 __LINE__); 1172 } 1173 1174 m->mtx_lock = MTX_DESTROYED; 1175 lock_destroy(&m->lock_object); 1176 } 1177 1178 /* 1179 * Intialize the mutex code and system mutexes. This is called from the MD 1180 * startup code prior to mi_startup(). The per-CPU data space needs to be 1181 * setup before this is called. 1182 */ 1183 void 1184 mutex_init(void) 1185 { 1186 1187 /* Setup turnstiles so that sleep mutexes work. */ 1188 init_turnstiles(); 1189 1190 /* 1191 * Initialize mutexes. 1192 */ 1193 mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE); 1194 mtx_init(&blocked_lock, "blocked lock", NULL, MTX_SPIN); 1195 blocked_lock.mtx_lock = 0xdeadc0de; /* Always blocked. */ 1196 mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK); 1197 mtx_init(&proc0.p_slock, "process slock", NULL, MTX_SPIN); 1198 mtx_init(&proc0.p_statmtx, "pstatl", NULL, MTX_SPIN); 1199 mtx_init(&proc0.p_itimmtx, "pitiml", NULL, MTX_SPIN); 1200 mtx_init(&proc0.p_profmtx, "pprofl", NULL, MTX_SPIN); 1201 mtx_init(&devmtx, "cdev", NULL, MTX_DEF); 1202 mtx_lock(&Giant); 1203 } 1204 1205 static void __noinline 1206 _mtx_lock_indefinite_check(struct mtx *m, struct lock_delay_arg *ldap) 1207 { 1208 struct thread *td; 1209 1210 ldap->spin_cnt++; 1211 if (ldap->spin_cnt < 60000000 || kdb_active || panicstr != NULL) 1212 DELAY(1); 1213 else { 1214 td = mtx_owner(m); 1215 1216 /* If the mutex is unlocked, try again. */ 1217 if (td == NULL) 1218 return; 1219 1220 printf( "spin lock %p (%s) held by %p (tid %d) too long\n", 1221 m, m->lock_object.lo_name, td, td->td_tid); 1222 #ifdef WITNESS 1223 witness_display_spinlock(&m->lock_object, td, printf); 1224 #endif 1225 panic("spin lock held too long"); 1226 } 1227 cpu_spinwait(); 1228 } 1229 1230 #ifdef DDB 1231 void 1232 db_show_mtx(const struct lock_object *lock) 1233 { 1234 struct thread *td; 1235 const struct mtx *m; 1236 1237 m = (const struct mtx *)lock; 1238 1239 db_printf(" flags: {"); 1240 if (LOCK_CLASS(lock) == &lock_class_mtx_spin) 1241 db_printf("SPIN"); 1242 else 1243 db_printf("DEF"); 1244 if (m->lock_object.lo_flags & LO_RECURSABLE) 1245 db_printf(", RECURSE"); 1246 if (m->lock_object.lo_flags & LO_DUPOK) 1247 db_printf(", DUPOK"); 1248 db_printf("}\n"); 1249 db_printf(" state: {"); 1250 if (mtx_unowned(m)) 1251 db_printf("UNOWNED"); 1252 else if (mtx_destroyed(m)) 1253 db_printf("DESTROYED"); 1254 else { 1255 db_printf("OWNED"); 1256 if (m->mtx_lock & MTX_CONTESTED) 1257 db_printf(", CONTESTED"); 1258 if (m->mtx_lock & MTX_RECURSED) 1259 db_printf(", RECURSED"); 1260 } 1261 db_printf("}\n"); 1262 if (!mtx_unowned(m) && !mtx_destroyed(m)) { 1263 td = mtx_owner(m); 1264 db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td, 1265 td->td_tid, td->td_proc->p_pid, td->td_name); 1266 if (mtx_recursed(m)) 1267 db_printf(" recursed: %d\n", m->mtx_recurse); 1268 } 1269 } 1270 #endif 1271