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