1 /*- 2 * Copyright (c) 2008 Attilio Rao <attilio@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice(s), this list of conditions and the following disclaimer as 10 * the first lines of this file unmodified other than the possible 11 * addition of one or more copyright notices. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice(s), this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 17 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 19 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY 20 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 21 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 22 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 23 * 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 SUCH 26 * DAMAGE. 27 */ 28 29 #include "opt_adaptive_lockmgrs.h" 30 #include "opt_ddb.h" 31 #include "opt_kdtrace.h" 32 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include <sys/param.h> 37 #include <sys/ktr.h> 38 #include <sys/linker_set.h> 39 #include <sys/lock.h> 40 #include <sys/lock_profile.h> 41 #include <sys/lockmgr.h> 42 #include <sys/mutex.h> 43 #include <sys/proc.h> 44 #include <sys/sleepqueue.h> 45 #ifdef DEBUG_LOCKS 46 #include <sys/stack.h> 47 #endif 48 #include <sys/sysctl.h> 49 #include <sys/systm.h> 50 51 #include <machine/cpu.h> 52 53 #ifdef DDB 54 #include <ddb/ddb.h> 55 #endif 56 57 CTASSERT(((LK_ADAPTIVE | LK_NOSHARE) & LO_CLASSFLAGS) == 58 (LK_ADAPTIVE | LK_NOSHARE)); 59 CTASSERT(LK_UNLOCKED == (LK_UNLOCKED & 60 ~(LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS))); 61 62 #define SQ_EXCLUSIVE_QUEUE 0 63 #define SQ_SHARED_QUEUE 1 64 65 #ifndef INVARIANTS 66 #define _lockmgr_assert(lk, what, file, line) 67 #define TD_LOCKS_INC(td) 68 #define TD_LOCKS_DEC(td) 69 #else 70 #define TD_LOCKS_INC(td) ((td)->td_locks++) 71 #define TD_LOCKS_DEC(td) ((td)->td_locks--) 72 #endif 73 #define TD_SLOCKS_INC(td) ((td)->td_lk_slocks++) 74 #define TD_SLOCKS_DEC(td) ((td)->td_lk_slocks--) 75 76 #ifndef DEBUG_LOCKS 77 #define STACK_PRINT(lk) 78 #define STACK_SAVE(lk) 79 #define STACK_ZERO(lk) 80 #else 81 #define STACK_PRINT(lk) stack_print_ddb(&(lk)->lk_stack) 82 #define STACK_SAVE(lk) stack_save(&(lk)->lk_stack) 83 #define STACK_ZERO(lk) stack_zero(&(lk)->lk_stack) 84 #endif 85 86 #define LOCK_LOG2(lk, string, arg1, arg2) \ 87 if (LOCK_LOG_TEST(&(lk)->lock_object, 0)) \ 88 CTR2(KTR_LOCK, (string), (arg1), (arg2)) 89 #define LOCK_LOG3(lk, string, arg1, arg2, arg3) \ 90 if (LOCK_LOG_TEST(&(lk)->lock_object, 0)) \ 91 CTR3(KTR_LOCK, (string), (arg1), (arg2), (arg3)) 92 93 #define GIANT_DECLARE \ 94 int _i = 0; \ 95 WITNESS_SAVE_DECL(Giant) 96 #define GIANT_RESTORE() do { \ 97 if (_i > 0) { \ 98 while (_i--) \ 99 mtx_lock(&Giant); \ 100 WITNESS_RESTORE(&Giant.lock_object, Giant); \ 101 } \ 102 } while (0) 103 #define GIANT_SAVE() do { \ 104 if (mtx_owned(&Giant)) { \ 105 WITNESS_SAVE(&Giant.lock_object, Giant); \ 106 while (mtx_owned(&Giant)) { \ 107 _i++; \ 108 mtx_unlock(&Giant); \ 109 } \ 110 } \ 111 } while (0) 112 113 #define LK_CAN_SHARE(x) \ 114 (((x) & LK_SHARE) && (((x) & LK_EXCLUSIVE_WAITERS) == 0 || \ 115 ((x) & LK_EXCLUSIVE_SPINNERS) == 0 || \ 116 curthread->td_lk_slocks || (curthread->td_pflags & TDP_DEADLKTREAT))) 117 #define LK_TRYOP(x) \ 118 ((x) & LK_NOWAIT) 119 120 #define LK_CAN_WITNESS(x) \ 121 (((x) & LK_NOWITNESS) == 0 && !LK_TRYOP(x)) 122 #define LK_TRYWIT(x) \ 123 (LK_TRYOP(x) ? LOP_TRYLOCK : 0) 124 125 #define LK_CAN_ADAPT(lk, f) \ 126 (((lk)->lock_object.lo_flags & LK_ADAPTIVE) != 0 && \ 127 ((f) & LK_SLEEPFAIL) == 0) 128 129 #define lockmgr_disowned(lk) \ 130 (((lk)->lk_lock & ~(LK_FLAGMASK & ~LK_SHARE)) == LK_KERNPROC) 131 132 #define lockmgr_xlocked(lk) \ 133 (((lk)->lk_lock & ~(LK_FLAGMASK & ~LK_SHARE)) == (uintptr_t)curthread) 134 135 static void assert_lockmgr(struct lock_object *lock, int how); 136 #ifdef DDB 137 static void db_show_lockmgr(struct lock_object *lock); 138 #endif 139 static void lock_lockmgr(struct lock_object *lock, int how); 140 #ifdef KDTRACE_HOOKS 141 static int owner_lockmgr(struct lock_object *lock, struct thread **owner); 142 #endif 143 static int unlock_lockmgr(struct lock_object *lock); 144 145 struct lock_class lock_class_lockmgr = { 146 .lc_name = "lockmgr", 147 .lc_flags = LC_RECURSABLE | LC_SLEEPABLE | LC_SLEEPLOCK | LC_UPGRADABLE, 148 .lc_assert = assert_lockmgr, 149 #ifdef DDB 150 .lc_ddb_show = db_show_lockmgr, 151 #endif 152 .lc_lock = lock_lockmgr, 153 .lc_unlock = unlock_lockmgr, 154 #ifdef KDTRACE_HOOKS 155 .lc_owner = owner_lockmgr, 156 #endif 157 }; 158 159 #ifdef ADAPTIVE_LOCKMGRS 160 static u_int alk_retries = 10; 161 static u_int alk_loops = 10000; 162 SYSCTL_NODE(_debug, OID_AUTO, lockmgr, CTLFLAG_RD, NULL, "lockmgr debugging"); 163 SYSCTL_UINT(_debug_lockmgr, OID_AUTO, retries, CTLFLAG_RW, &alk_retries, 0, ""); 164 SYSCTL_UINT(_debug_lockmgr, OID_AUTO, loops, CTLFLAG_RW, &alk_loops, 0, ""); 165 #endif 166 167 static __inline struct thread * 168 lockmgr_xholder(struct lock *lk) 169 { 170 uintptr_t x; 171 172 x = lk->lk_lock; 173 return ((x & LK_SHARE) ? NULL : (struct thread *)LK_HOLDER(x)); 174 } 175 176 /* 177 * It assumes sleepq_lock held and returns with this one unheld. 178 * It also assumes the generic interlock is sane and previously checked. 179 * If LK_INTERLOCK is specified the interlock is not reacquired after the 180 * sleep. 181 */ 182 static __inline int 183 sleeplk(struct lock *lk, u_int flags, struct lock_object *ilk, 184 const char *wmesg, int pri, int timo, int queue) 185 { 186 GIANT_DECLARE; 187 struct lock_class *class; 188 int catch, error; 189 190 class = (flags & LK_INTERLOCK) ? LOCK_CLASS(ilk) : NULL; 191 catch = pri & PCATCH; 192 pri &= PRIMASK; 193 error = 0; 194 195 LOCK_LOG3(lk, "%s: %p blocking on the %s sleepqueue", __func__, lk, 196 (queue == SQ_EXCLUSIVE_QUEUE) ? "exclusive" : "shared"); 197 198 if (flags & LK_INTERLOCK) 199 class->lc_unlock(ilk); 200 GIANT_SAVE(); 201 sleepq_add(&lk->lock_object, NULL, wmesg, SLEEPQ_LK | (catch ? 202 SLEEPQ_INTERRUPTIBLE : 0), queue); 203 if ((flags & LK_TIMELOCK) && timo) 204 sleepq_set_timeout(&lk->lock_object, timo); 205 206 /* 207 * Decisional switch for real sleeping. 208 */ 209 if ((flags & LK_TIMELOCK) && timo && catch) 210 error = sleepq_timedwait_sig(&lk->lock_object, pri); 211 else if ((flags & LK_TIMELOCK) && timo) 212 error = sleepq_timedwait(&lk->lock_object, pri); 213 else if (catch) 214 error = sleepq_wait_sig(&lk->lock_object, pri); 215 else 216 sleepq_wait(&lk->lock_object, pri); 217 GIANT_RESTORE(); 218 if ((flags & LK_SLEEPFAIL) && error == 0) 219 error = ENOLCK; 220 221 return (error); 222 } 223 224 static __inline int 225 wakeupshlk(struct lock *lk, const char *file, int line) 226 { 227 uintptr_t v, x; 228 int queue, wakeup_swapper; 229 230 TD_LOCKS_DEC(curthread); 231 TD_SLOCKS_DEC(curthread); 232 WITNESS_UNLOCK(&lk->lock_object, 0, file, line); 233 LOCK_LOG_LOCK("SUNLOCK", &lk->lock_object, 0, 0, file, line); 234 235 wakeup_swapper = 0; 236 for (;;) { 237 x = lk->lk_lock; 238 239 /* 240 * If there is more than one shared lock held, just drop one 241 * and return. 242 */ 243 if (LK_SHARERS(x) > 1) { 244 if (atomic_cmpset_ptr(&lk->lk_lock, x, 245 x - LK_ONE_SHARER)) 246 break; 247 continue; 248 } 249 250 /* 251 * If there are not waiters on the exclusive queue, drop the 252 * lock quickly. 253 */ 254 if ((x & LK_ALL_WAITERS) == 0) { 255 MPASS((x & ~LK_EXCLUSIVE_SPINNERS) == 256 LK_SHARERS_LOCK(1)); 257 if (atomic_cmpset_ptr(&lk->lk_lock, x, LK_UNLOCKED)) 258 break; 259 continue; 260 } 261 262 /* 263 * We should have a sharer with waiters, so enter the hard 264 * path in order to handle wakeups correctly. 265 */ 266 sleepq_lock(&lk->lock_object); 267 x = lk->lk_lock & (LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS); 268 v = LK_UNLOCKED; 269 270 /* 271 * If the lock has exclusive waiters, give them preference in 272 * order to avoid deadlock with shared runners up. 273 */ 274 if (x & LK_EXCLUSIVE_WAITERS) { 275 queue = SQ_EXCLUSIVE_QUEUE; 276 v |= (x & LK_SHARED_WAITERS); 277 } else { 278 MPASS((x & ~LK_EXCLUSIVE_SPINNERS) == 279 LK_SHARED_WAITERS); 280 queue = SQ_SHARED_QUEUE; 281 } 282 283 if (!atomic_cmpset_ptr(&lk->lk_lock, LK_SHARERS_LOCK(1) | x, 284 v)) { 285 sleepq_release(&lk->lock_object); 286 continue; 287 } 288 LOCK_LOG3(lk, "%s: %p waking up threads on the %s queue", 289 __func__, lk, queue == SQ_SHARED_QUEUE ? "shared" : 290 "exclusive"); 291 wakeup_swapper = sleepq_broadcast(&lk->lock_object, SLEEPQ_LK, 292 0, queue); 293 sleepq_release(&lk->lock_object); 294 break; 295 } 296 297 lock_profile_release_lock(&lk->lock_object); 298 return (wakeup_swapper); 299 } 300 301 static void 302 assert_lockmgr(struct lock_object *lock, int what) 303 { 304 305 panic("lockmgr locks do not support assertions"); 306 } 307 308 static void 309 lock_lockmgr(struct lock_object *lock, int how) 310 { 311 312 panic("lockmgr locks do not support sleep interlocking"); 313 } 314 315 static int 316 unlock_lockmgr(struct lock_object *lock) 317 { 318 319 panic("lockmgr locks do not support sleep interlocking"); 320 } 321 322 #ifdef KDTRACE_HOOKS 323 static int 324 owner_lockmgr(struct lock_object *lock, struct thread **owner) 325 { 326 327 panic("lockmgr locks do not support owner inquiring"); 328 } 329 #endif 330 331 void 332 lockinit(struct lock *lk, int pri, const char *wmesg, int timo, int flags) 333 { 334 int iflags; 335 336 MPASS((flags & ~LK_INIT_MASK) == 0); 337 338 iflags = LO_SLEEPABLE | LO_UPGRADABLE; 339 if (flags & LK_CANRECURSE) 340 iflags |= LO_RECURSABLE; 341 if ((flags & LK_NODUP) == 0) 342 iflags |= LO_DUPOK; 343 if (flags & LK_NOPROFILE) 344 iflags |= LO_NOPROFILE; 345 if ((flags & LK_NOWITNESS) == 0) 346 iflags |= LO_WITNESS; 347 if (flags & LK_QUIET) 348 iflags |= LO_QUIET; 349 iflags |= flags & (LK_ADAPTIVE | LK_NOSHARE); 350 351 lk->lk_lock = LK_UNLOCKED; 352 lk->lk_recurse = 0; 353 lk->lk_timo = timo; 354 lk->lk_pri = pri; 355 lock_init(&lk->lock_object, &lock_class_lockmgr, wmesg, NULL, iflags); 356 STACK_ZERO(lk); 357 } 358 359 void 360 lockdestroy(struct lock *lk) 361 { 362 363 KASSERT(lk->lk_lock == LK_UNLOCKED, ("lockmgr still held")); 364 KASSERT(lk->lk_recurse == 0, ("lockmgr still recursed")); 365 lock_destroy(&lk->lock_object); 366 } 367 368 int 369 __lockmgr_args(struct lock *lk, u_int flags, struct lock_object *ilk, 370 const char *wmesg, int pri, int timo, const char *file, int line) 371 { 372 GIANT_DECLARE; 373 struct lock_class *class; 374 const char *iwmesg; 375 uintptr_t tid, v, x; 376 u_int op; 377 int error, ipri, itimo, queue, wakeup_swapper; 378 #ifdef LOCK_PROFILING 379 uint64_t waittime = 0; 380 int contested = 0; 381 #endif 382 #ifdef ADAPTIVE_LOCKMGRS 383 volatile struct thread *owner; 384 u_int i, spintries = 0; 385 #endif 386 387 error = 0; 388 tid = (uintptr_t)curthread; 389 op = (flags & LK_TYPE_MASK); 390 iwmesg = (wmesg == LK_WMESG_DEFAULT) ? lk->lock_object.lo_name : wmesg; 391 ipri = (pri == LK_PRIO_DEFAULT) ? lk->lk_pri : pri; 392 itimo = (timo == LK_TIMO_DEFAULT) ? lk->lk_timo : timo; 393 394 MPASS((flags & ~LK_TOTAL_MASK) == 0); 395 KASSERT((op & (op - 1)) == 0, 396 ("%s: Invalid requested operation @ %s:%d", __func__, file, line)); 397 KASSERT((flags & (LK_NOWAIT | LK_SLEEPFAIL)) == 0 || 398 (op != LK_DOWNGRADE && op != LK_RELEASE), 399 ("%s: Invalid flags in regard of the operation desired @ %s:%d", 400 __func__, file, line)); 401 KASSERT((flags & LK_INTERLOCK) == 0 || ilk != NULL, 402 ("%s: LK_INTERLOCK passed without valid interlock @ %s:%d", 403 __func__, file, line)); 404 405 class = (flags & LK_INTERLOCK) ? LOCK_CLASS(ilk) : NULL; 406 if (panicstr != NULL) { 407 if (flags & LK_INTERLOCK) 408 class->lc_unlock(ilk); 409 return (0); 410 } 411 412 if (op == LK_SHARED && (lk->lock_object.lo_flags & LK_NOSHARE)) 413 op = LK_EXCLUSIVE; 414 415 wakeup_swapper = 0; 416 switch (op) { 417 case LK_SHARED: 418 if (LK_CAN_WITNESS(flags)) 419 WITNESS_CHECKORDER(&lk->lock_object, LOP_NEWORDER, 420 file, line, ilk); 421 for (;;) { 422 x = lk->lk_lock; 423 424 /* 425 * If no other thread has an exclusive lock, or 426 * no exclusive waiter is present, bump the count of 427 * sharers. Since we have to preserve the state of 428 * waiters, if we fail to acquire the shared lock 429 * loop back and retry. 430 */ 431 if (LK_CAN_SHARE(x)) { 432 if (atomic_cmpset_acq_ptr(&lk->lk_lock, x, 433 x + LK_ONE_SHARER)) 434 break; 435 continue; 436 } 437 lock_profile_obtain_lock_failed(&lk->lock_object, 438 &contested, &waittime); 439 440 /* 441 * If the lock is already held by curthread in 442 * exclusive way avoid a deadlock. 443 */ 444 if (LK_HOLDER(x) == tid) { 445 LOCK_LOG2(lk, 446 "%s: %p already held in exclusive mode", 447 __func__, lk); 448 error = EDEADLK; 449 break; 450 } 451 452 /* 453 * If the lock is expected to not sleep just give up 454 * and return. 455 */ 456 if (LK_TRYOP(flags)) { 457 LOCK_LOG2(lk, "%s: %p fails the try operation", 458 __func__, lk); 459 error = EBUSY; 460 break; 461 } 462 463 #ifdef ADAPTIVE_LOCKMGRS 464 /* 465 * If the owner is running on another CPU, spin until 466 * the owner stops running or the state of the lock 467 * changes. 468 */ 469 if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && 470 LK_HOLDER(x) != LK_KERNPROC) { 471 owner = (struct thread *)LK_HOLDER(x); 472 if (LOCK_LOG_TEST(&lk->lock_object, 0)) 473 CTR3(KTR_LOCK, 474 "%s: spinning on %p held by %p", 475 __func__, lk, owner); 476 477 /* 478 * If we are holding also an interlock drop it 479 * in order to avoid a deadlock if the lockmgr 480 * owner is adaptively spinning on the 481 * interlock itself. 482 */ 483 if (flags & LK_INTERLOCK) { 484 class->lc_unlock(ilk); 485 flags &= ~LK_INTERLOCK; 486 } 487 GIANT_SAVE(); 488 while (LK_HOLDER(lk->lk_lock) == 489 (uintptr_t)owner && TD_IS_RUNNING(owner)) 490 cpu_spinwait(); 491 } else if (LK_CAN_ADAPT(lk, flags) && 492 (x & LK_SHARE) !=0 && LK_SHARERS(x) && 493 spintries < alk_retries) { 494 if (flags & LK_INTERLOCK) { 495 class->lc_unlock(ilk); 496 flags &= ~LK_INTERLOCK; 497 } 498 GIANT_SAVE(); 499 spintries++; 500 for (i = 0; i < alk_loops; i++) { 501 if (LOCK_LOG_TEST(&lk->lock_object, 0)) 502 CTR4(KTR_LOCK, 503 "%s: shared spinning on %p with %u and %u", 504 __func__, lk, spintries, i); 505 x = lk->lk_lock; 506 if ((x & LK_SHARE) == 0 || 507 LK_CAN_SHARE(x) != 0) 508 break; 509 cpu_spinwait(); 510 } 511 if (i != alk_loops) 512 continue; 513 } 514 #endif 515 516 /* 517 * Acquire the sleepqueue chain lock because we 518 * probabilly will need to manipulate waiters flags. 519 */ 520 sleepq_lock(&lk->lock_object); 521 x = lk->lk_lock; 522 523 /* 524 * if the lock can be acquired in shared mode, try 525 * again. 526 */ 527 if (LK_CAN_SHARE(x)) { 528 sleepq_release(&lk->lock_object); 529 continue; 530 } 531 532 #ifdef ADAPTIVE_LOCKMGRS 533 /* 534 * The current lock owner might have started executing 535 * on another CPU (or the lock could have changed 536 * owner) while we were waiting on the turnstile 537 * chain lock. If so, drop the turnstile lock and try 538 * again. 539 */ 540 if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && 541 LK_HOLDER(x) != LK_KERNPROC) { 542 owner = (struct thread *)LK_HOLDER(x); 543 if (TD_IS_RUNNING(owner)) { 544 sleepq_release(&lk->lock_object); 545 continue; 546 } 547 } 548 #endif 549 550 /* 551 * Try to set the LK_SHARED_WAITERS flag. If we fail, 552 * loop back and retry. 553 */ 554 if ((x & LK_SHARED_WAITERS) == 0) { 555 if (!atomic_cmpset_acq_ptr(&lk->lk_lock, x, 556 x | LK_SHARED_WAITERS)) { 557 sleepq_release(&lk->lock_object); 558 continue; 559 } 560 LOCK_LOG2(lk, "%s: %p set shared waiters flag", 561 __func__, lk); 562 } 563 564 /* 565 * As far as we have been unable to acquire the 566 * shared lock and the shared waiters flag is set, 567 * we will sleep. 568 */ 569 error = sleeplk(lk, flags, ilk, iwmesg, ipri, itimo, 570 SQ_SHARED_QUEUE); 571 flags &= ~LK_INTERLOCK; 572 if (error) { 573 LOCK_LOG3(lk, 574 "%s: interrupted sleep for %p with %d", 575 __func__, lk, error); 576 break; 577 } 578 LOCK_LOG2(lk, "%s: %p resuming from the sleep queue", 579 __func__, lk); 580 } 581 if (error == 0) { 582 lock_profile_obtain_lock_success(&lk->lock_object, 583 contested, waittime, file, line); 584 LOCK_LOG_LOCK("SLOCK", &lk->lock_object, 0, 0, file, 585 line); 586 WITNESS_LOCK(&lk->lock_object, LK_TRYWIT(flags), file, 587 line); 588 TD_LOCKS_INC(curthread); 589 TD_SLOCKS_INC(curthread); 590 STACK_SAVE(lk); 591 } 592 break; 593 case LK_UPGRADE: 594 _lockmgr_assert(lk, KA_SLOCKED, file, line); 595 v = lk->lk_lock; 596 x = v & LK_ALL_WAITERS; 597 v &= LK_EXCLUSIVE_SPINNERS; 598 599 /* 600 * Try to switch from one shared lock to an exclusive one. 601 * We need to preserve waiters flags during the operation. 602 */ 603 if (atomic_cmpset_ptr(&lk->lk_lock, LK_SHARERS_LOCK(1) | x | v, 604 tid | x)) { 605 LOCK_LOG_LOCK("XUPGRADE", &lk->lock_object, 0, 0, file, 606 line); 607 WITNESS_UPGRADE(&lk->lock_object, LOP_EXCLUSIVE | 608 LK_TRYWIT(flags), file, line); 609 TD_SLOCKS_DEC(curthread); 610 break; 611 } 612 613 /* 614 * We have been unable to succeed in upgrading, so just 615 * give up the shared lock. 616 */ 617 wakeup_swapper |= wakeupshlk(lk, file, line); 618 619 /* FALLTHROUGH */ 620 case LK_EXCLUSIVE: 621 if (LK_CAN_WITNESS(flags)) 622 WITNESS_CHECKORDER(&lk->lock_object, LOP_NEWORDER | 623 LOP_EXCLUSIVE, file, line, ilk); 624 625 /* 626 * If curthread already holds the lock and this one is 627 * allowed to recurse, simply recurse on it. 628 */ 629 if (lockmgr_xlocked(lk)) { 630 if ((flags & LK_CANRECURSE) == 0 && 631 (lk->lock_object.lo_flags & LO_RECURSABLE) == 0) { 632 633 /* 634 * If the lock is expected to not panic just 635 * give up and return. 636 */ 637 if (LK_TRYOP(flags)) { 638 LOCK_LOG2(lk, 639 "%s: %p fails the try operation", 640 __func__, lk); 641 error = EBUSY; 642 break; 643 } 644 if (flags & LK_INTERLOCK) 645 class->lc_unlock(ilk); 646 panic("%s: recursing on non recursive lockmgr %s @ %s:%d\n", 647 __func__, iwmesg, file, line); 648 } 649 lk->lk_recurse++; 650 LOCK_LOG2(lk, "%s: %p recursing", __func__, lk); 651 LOCK_LOG_LOCK("XLOCK", &lk->lock_object, 0, 652 lk->lk_recurse, file, line); 653 WITNESS_LOCK(&lk->lock_object, LOP_EXCLUSIVE | 654 LK_TRYWIT(flags), file, line); 655 TD_LOCKS_INC(curthread); 656 break; 657 } 658 659 while (!atomic_cmpset_acq_ptr(&lk->lk_lock, LK_UNLOCKED, 660 tid)) { 661 lock_profile_obtain_lock_failed(&lk->lock_object, 662 &contested, &waittime); 663 664 /* 665 * If the lock is expected to not sleep just give up 666 * and return. 667 */ 668 if (LK_TRYOP(flags)) { 669 LOCK_LOG2(lk, "%s: %p fails the try operation", 670 __func__, lk); 671 error = EBUSY; 672 break; 673 } 674 675 #ifdef ADAPTIVE_LOCKMGRS 676 /* 677 * If the owner is running on another CPU, spin until 678 * the owner stops running or the state of the lock 679 * changes. 680 */ 681 x = lk->lk_lock; 682 if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && 683 LK_HOLDER(x) != LK_KERNPROC) { 684 owner = (struct thread *)LK_HOLDER(x); 685 if (LOCK_LOG_TEST(&lk->lock_object, 0)) 686 CTR3(KTR_LOCK, 687 "%s: spinning on %p held by %p", 688 __func__, lk, owner); 689 690 /* 691 * If we are holding also an interlock drop it 692 * in order to avoid a deadlock if the lockmgr 693 * owner is adaptively spinning on the 694 * interlock itself. 695 */ 696 if (flags & LK_INTERLOCK) { 697 class->lc_unlock(ilk); 698 flags &= ~LK_INTERLOCK; 699 } 700 GIANT_SAVE(); 701 while (LK_HOLDER(lk->lk_lock) == 702 (uintptr_t)owner && TD_IS_RUNNING(owner)) 703 cpu_spinwait(); 704 } else if (LK_CAN_ADAPT(lk, flags) && 705 (x & LK_SHARE) != 0 && LK_SHARERS(x) && 706 spintries < alk_retries) { 707 if ((x & LK_EXCLUSIVE_SPINNERS) == 0 && 708 !atomic_cmpset_ptr(&lk->lk_lock, x, 709 x | LK_EXCLUSIVE_SPINNERS)) 710 continue; 711 if (flags & LK_INTERLOCK) { 712 class->lc_unlock(ilk); 713 flags &= ~LK_INTERLOCK; 714 } 715 GIANT_SAVE(); 716 spintries++; 717 for (i = 0; i < alk_loops; i++) { 718 if (LOCK_LOG_TEST(&lk->lock_object, 0)) 719 CTR4(KTR_LOCK, 720 "%s: shared spinning on %p with %u and %u", 721 __func__, lk, spintries, i); 722 if ((lk->lk_lock & 723 LK_EXCLUSIVE_SPINNERS) == 0) 724 break; 725 cpu_spinwait(); 726 } 727 if (i != alk_loops) 728 continue; 729 } 730 #endif 731 732 /* 733 * Acquire the sleepqueue chain lock because we 734 * probabilly will need to manipulate waiters flags. 735 */ 736 sleepq_lock(&lk->lock_object); 737 x = lk->lk_lock; 738 739 /* 740 * if the lock has been released while we spun on 741 * the sleepqueue chain lock just try again. 742 */ 743 if (x == LK_UNLOCKED) { 744 sleepq_release(&lk->lock_object); 745 continue; 746 } 747 748 #ifdef ADAPTIVE_LOCKMGRS 749 /* 750 * The current lock owner might have started executing 751 * on another CPU (or the lock could have changed 752 * owner) while we were waiting on the turnstile 753 * chain lock. If so, drop the turnstile lock and try 754 * again. 755 */ 756 if (LK_CAN_ADAPT(lk, flags) && (x & LK_SHARE) == 0 && 757 LK_HOLDER(x) != LK_KERNPROC) { 758 owner = (struct thread *)LK_HOLDER(x); 759 if (TD_IS_RUNNING(owner)) { 760 sleepq_release(&lk->lock_object); 761 continue; 762 } 763 } 764 #endif 765 766 /* 767 * The lock can be in the state where there is a 768 * pending queue of waiters, but still no owner. 769 * This happens when the lock is contested and an 770 * owner is going to claim the lock. 771 * If curthread is the one successfully acquiring it 772 * claim lock ownership and return, preserving waiters 773 * flags. 774 */ 775 v = x & (LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS); 776 if ((x & ~v) == LK_UNLOCKED) { 777 v &= ~LK_EXCLUSIVE_SPINNERS; 778 if (atomic_cmpset_acq_ptr(&lk->lk_lock, x, 779 tid | v)) { 780 sleepq_release(&lk->lock_object); 781 LOCK_LOG2(lk, 782 "%s: %p claimed by a new writer", 783 __func__, lk); 784 break; 785 } 786 sleepq_release(&lk->lock_object); 787 continue; 788 } 789 790 /* 791 * Try to set the LK_EXCLUSIVE_WAITERS flag. If we 792 * fail, loop back and retry. 793 */ 794 if ((x & LK_EXCLUSIVE_WAITERS) == 0) { 795 if (!atomic_cmpset_ptr(&lk->lk_lock, x, 796 x | LK_EXCLUSIVE_WAITERS)) { 797 sleepq_release(&lk->lock_object); 798 continue; 799 } 800 LOCK_LOG2(lk, "%s: %p set excl waiters flag", 801 __func__, lk); 802 } 803 804 /* 805 * As far as we have been unable to acquire the 806 * exclusive lock and the exclusive waiters flag 807 * is set, we will sleep. 808 */ 809 error = sleeplk(lk, flags, ilk, iwmesg, ipri, itimo, 810 SQ_EXCLUSIVE_QUEUE); 811 flags &= ~LK_INTERLOCK; 812 if (error) { 813 LOCK_LOG3(lk, 814 "%s: interrupted sleep for %p with %d", 815 __func__, lk, error); 816 break; 817 } 818 LOCK_LOG2(lk, "%s: %p resuming from the sleep queue", 819 __func__, lk); 820 } 821 if (error == 0) { 822 lock_profile_obtain_lock_success(&lk->lock_object, 823 contested, waittime, file, line); 824 LOCK_LOG_LOCK("XLOCK", &lk->lock_object, 0, 825 lk->lk_recurse, file, line); 826 WITNESS_LOCK(&lk->lock_object, LOP_EXCLUSIVE | 827 LK_TRYWIT(flags), file, line); 828 TD_LOCKS_INC(curthread); 829 STACK_SAVE(lk); 830 } 831 break; 832 case LK_DOWNGRADE: 833 _lockmgr_assert(lk, KA_XLOCKED | KA_NOTRECURSED, file, line); 834 LOCK_LOG_LOCK("XDOWNGRADE", &lk->lock_object, 0, 0, file, line); 835 WITNESS_DOWNGRADE(&lk->lock_object, 0, file, line); 836 TD_SLOCKS_INC(curthread); 837 838 /* 839 * In order to preserve waiters flags, just spin. 840 */ 841 for (;;) { 842 x = lk->lk_lock; 843 MPASS((x & LK_EXCLUSIVE_SPINNERS) == 0); 844 x &= LK_ALL_WAITERS; 845 if (atomic_cmpset_rel_ptr(&lk->lk_lock, tid | x, 846 LK_SHARERS_LOCK(1) | x)) 847 break; 848 cpu_spinwait(); 849 } 850 break; 851 case LK_RELEASE: 852 _lockmgr_assert(lk, KA_LOCKED, file, line); 853 x = lk->lk_lock; 854 855 if ((x & LK_SHARE) == 0) { 856 857 /* 858 * As first option, treact the lock as if it has not 859 * any waiter. 860 * Fix-up the tid var if the lock has been disowned. 861 */ 862 if (LK_HOLDER(x) == LK_KERNPROC) 863 tid = LK_KERNPROC; 864 else { 865 WITNESS_UNLOCK(&lk->lock_object, LOP_EXCLUSIVE, 866 file, line); 867 TD_LOCKS_DEC(curthread); 868 } 869 LOCK_LOG_LOCK("XUNLOCK", &lk->lock_object, 0, 870 lk->lk_recurse, file, line); 871 872 /* 873 * The lock is held in exclusive mode. 874 * If the lock is recursed also, then unrecurse it. 875 */ 876 if (lockmgr_xlocked(lk) && lockmgr_recursed(lk)) { 877 LOCK_LOG2(lk, "%s: %p unrecursing", __func__, 878 lk); 879 lk->lk_recurse--; 880 break; 881 } 882 if (tid != LK_KERNPROC) 883 lock_profile_release_lock(&lk->lock_object); 884 885 if (atomic_cmpset_rel_ptr(&lk->lk_lock, tid, 886 LK_UNLOCKED)) 887 break; 888 889 sleepq_lock(&lk->lock_object); 890 x = lk->lk_lock; 891 v = LK_UNLOCKED; 892 893 /* 894 * If the lock has exclusive waiters, give them 895 * preference in order to avoid deadlock with 896 * shared runners up. 897 */ 898 MPASS((x & LK_EXCLUSIVE_SPINNERS) == 0); 899 if (x & LK_EXCLUSIVE_WAITERS) { 900 queue = SQ_EXCLUSIVE_QUEUE; 901 v |= (x & LK_SHARED_WAITERS); 902 } else { 903 MPASS((x & LK_ALL_WAITERS) == 904 LK_SHARED_WAITERS); 905 queue = SQ_SHARED_QUEUE; 906 } 907 908 LOCK_LOG3(lk, 909 "%s: %p waking up threads on the %s queue", 910 __func__, lk, queue == SQ_SHARED_QUEUE ? "shared" : 911 "exclusive"); 912 atomic_store_rel_ptr(&lk->lk_lock, v); 913 wakeup_swapper = sleepq_broadcast(&lk->lock_object, 914 SLEEPQ_LK, 0, queue); 915 sleepq_release(&lk->lock_object); 916 break; 917 } else 918 wakeup_swapper = wakeupshlk(lk, file, line); 919 break; 920 case LK_DRAIN: 921 if (LK_CAN_WITNESS(flags)) 922 WITNESS_CHECKORDER(&lk->lock_object, LOP_NEWORDER | 923 LOP_EXCLUSIVE, file, line, ilk); 924 925 /* 926 * Trying to drain a lock we already own will result in a 927 * deadlock. 928 */ 929 if (lockmgr_xlocked(lk)) { 930 if (flags & LK_INTERLOCK) 931 class->lc_unlock(ilk); 932 panic("%s: draining %s with the lock held @ %s:%d\n", 933 __func__, iwmesg, file, line); 934 } 935 936 while (!atomic_cmpset_acq_ptr(&lk->lk_lock, LK_UNLOCKED, tid)) { 937 lock_profile_obtain_lock_failed(&lk->lock_object, 938 &contested, &waittime); 939 940 /* 941 * If the lock is expected to not sleep just give up 942 * and return. 943 */ 944 if (LK_TRYOP(flags)) { 945 LOCK_LOG2(lk, "%s: %p fails the try operation", 946 __func__, lk); 947 error = EBUSY; 948 break; 949 } 950 951 /* 952 * Acquire the sleepqueue chain lock because we 953 * probabilly will need to manipulate waiters flags. 954 */ 955 sleepq_lock(&lk->lock_object); 956 x = lk->lk_lock; 957 958 /* 959 * if the lock has been released while we spun on 960 * the sleepqueue chain lock just try again. 961 */ 962 if (x == LK_UNLOCKED) { 963 sleepq_release(&lk->lock_object); 964 continue; 965 } 966 967 v = x & (LK_ALL_WAITERS | LK_EXCLUSIVE_SPINNERS); 968 if ((x & ~v) == LK_UNLOCKED) { 969 v = (x & ~LK_EXCLUSIVE_SPINNERS); 970 if (v & LK_EXCLUSIVE_WAITERS) { 971 queue = SQ_EXCLUSIVE_QUEUE; 972 v &= ~LK_EXCLUSIVE_WAITERS; 973 } else { 974 MPASS(v & LK_SHARED_WAITERS); 975 queue = SQ_SHARED_QUEUE; 976 v &= ~LK_SHARED_WAITERS; 977 } 978 if (!atomic_cmpset_ptr(&lk->lk_lock, x, v)) { 979 sleepq_release(&lk->lock_object); 980 continue; 981 } 982 LOCK_LOG3(lk, 983 "%s: %p waking up all threads on the %s queue", 984 __func__, lk, queue == SQ_SHARED_QUEUE ? 985 "shared" : "exclusive"); 986 wakeup_swapper |= sleepq_broadcast( 987 &lk->lock_object, SLEEPQ_LK, 0, queue); 988 989 /* 990 * If shared waiters have been woken up we need 991 * to wait for one of them to acquire the lock 992 * before to set the exclusive waiters in 993 * order to avoid a deadlock. 994 */ 995 if (queue == SQ_SHARED_QUEUE) { 996 for (v = lk->lk_lock; 997 (v & LK_SHARE) && !LK_SHARERS(v); 998 v = lk->lk_lock) 999 cpu_spinwait(); 1000 } 1001 } 1002 1003 /* 1004 * Try to set the LK_EXCLUSIVE_WAITERS flag. If we 1005 * fail, loop back and retry. 1006 */ 1007 if ((x & LK_EXCLUSIVE_WAITERS) == 0) { 1008 if (!atomic_cmpset_ptr(&lk->lk_lock, x, 1009 x | LK_EXCLUSIVE_WAITERS)) { 1010 sleepq_release(&lk->lock_object); 1011 continue; 1012 } 1013 LOCK_LOG2(lk, "%s: %p set drain waiters flag", 1014 __func__, lk); 1015 } 1016 1017 /* 1018 * As far as we have been unable to acquire the 1019 * exclusive lock and the exclusive waiters flag 1020 * is set, we will sleep. 1021 */ 1022 if (flags & LK_INTERLOCK) { 1023 class->lc_unlock(ilk); 1024 flags &= ~LK_INTERLOCK; 1025 } 1026 GIANT_SAVE(); 1027 sleepq_add(&lk->lock_object, NULL, iwmesg, SLEEPQ_LK, 1028 SQ_EXCLUSIVE_QUEUE); 1029 sleepq_wait(&lk->lock_object, ipri & PRIMASK); 1030 GIANT_RESTORE(); 1031 LOCK_LOG2(lk, "%s: %p resuming from the sleep queue", 1032 __func__, lk); 1033 } 1034 1035 if (error == 0) { 1036 lock_profile_obtain_lock_success(&lk->lock_object, 1037 contested, waittime, file, line); 1038 LOCK_LOG_LOCK("DRAIN", &lk->lock_object, 0, 1039 lk->lk_recurse, file, line); 1040 WITNESS_LOCK(&lk->lock_object, LOP_EXCLUSIVE | 1041 LK_TRYWIT(flags), file, line); 1042 TD_LOCKS_INC(curthread); 1043 STACK_SAVE(lk); 1044 } 1045 break; 1046 default: 1047 if (flags & LK_INTERLOCK) 1048 class->lc_unlock(ilk); 1049 panic("%s: unknown lockmgr request 0x%x\n", __func__, op); 1050 } 1051 1052 if (flags & LK_INTERLOCK) 1053 class->lc_unlock(ilk); 1054 if (wakeup_swapper) 1055 kick_proc0(); 1056 1057 return (error); 1058 } 1059 1060 void 1061 _lockmgr_disown(struct lock *lk, const char *file, int line) 1062 { 1063 uintptr_t tid, x; 1064 1065 tid = (uintptr_t)curthread; 1066 _lockmgr_assert(lk, KA_XLOCKED | KA_NOTRECURSED, file, line); 1067 1068 /* 1069 * If the owner is already LK_KERNPROC just skip the whole operation. 1070 */ 1071 if (LK_HOLDER(lk->lk_lock) != tid) 1072 return; 1073 lock_profile_release_lock(&lk->lock_object); 1074 LOCK_LOG_LOCK("XDISOWN", &lk->lock_object, 0, 0, file, line); 1075 WITNESS_UNLOCK(&lk->lock_object, LOP_EXCLUSIVE, file, line); 1076 TD_LOCKS_DEC(curthread); 1077 1078 /* 1079 * In order to preserve waiters flags, just spin. 1080 */ 1081 for (;;) { 1082 x = lk->lk_lock; 1083 MPASS((x & LK_EXCLUSIVE_SPINNERS) == 0); 1084 x &= LK_ALL_WAITERS; 1085 if (atomic_cmpset_rel_ptr(&lk->lk_lock, tid | x, 1086 LK_KERNPROC | x)) 1087 return; 1088 cpu_spinwait(); 1089 } 1090 } 1091 1092 void 1093 lockmgr_printinfo(struct lock *lk) 1094 { 1095 struct thread *td; 1096 uintptr_t x; 1097 1098 if (lk->lk_lock == LK_UNLOCKED) 1099 printf("lock type %s: UNLOCKED\n", lk->lock_object.lo_name); 1100 else if (lk->lk_lock & LK_SHARE) 1101 printf("lock type %s: SHARED (count %ju)\n", 1102 lk->lock_object.lo_name, 1103 (uintmax_t)LK_SHARERS(lk->lk_lock)); 1104 else { 1105 td = lockmgr_xholder(lk); 1106 printf("lock type %s: EXCL by thread %p (pid %d)\n", 1107 lk->lock_object.lo_name, td, td->td_proc->p_pid); 1108 } 1109 1110 x = lk->lk_lock; 1111 if (x & LK_EXCLUSIVE_WAITERS) 1112 printf(" with exclusive waiters pending\n"); 1113 if (x & LK_SHARED_WAITERS) 1114 printf(" with shared waiters pending\n"); 1115 if (x & LK_EXCLUSIVE_SPINNERS) 1116 printf(" with exclusive spinners pending\n"); 1117 1118 STACK_PRINT(lk); 1119 } 1120 1121 int 1122 lockstatus(struct lock *lk) 1123 { 1124 uintptr_t v, x; 1125 int ret; 1126 1127 ret = LK_SHARED; 1128 x = lk->lk_lock; 1129 v = LK_HOLDER(x); 1130 1131 if ((x & LK_SHARE) == 0) { 1132 if (v == (uintptr_t)curthread || v == LK_KERNPROC) 1133 ret = LK_EXCLUSIVE; 1134 else 1135 ret = LK_EXCLOTHER; 1136 } else if (x == LK_UNLOCKED) 1137 ret = 0; 1138 1139 return (ret); 1140 } 1141 1142 #ifdef INVARIANT_SUPPORT 1143 #ifndef INVARIANTS 1144 #undef _lockmgr_assert 1145 #endif 1146 1147 void 1148 _lockmgr_assert(struct lock *lk, int what, const char *file, int line) 1149 { 1150 int slocked = 0; 1151 1152 if (panicstr != NULL) 1153 return; 1154 switch (what) { 1155 case KA_SLOCKED: 1156 case KA_SLOCKED | KA_NOTRECURSED: 1157 case KA_SLOCKED | KA_RECURSED: 1158 slocked = 1; 1159 case KA_LOCKED: 1160 case KA_LOCKED | KA_NOTRECURSED: 1161 case KA_LOCKED | KA_RECURSED: 1162 #ifdef WITNESS 1163 1164 /* 1165 * We cannot trust WITNESS if the lock is held in exclusive 1166 * mode and a call to lockmgr_disown() happened. 1167 * Workaround this skipping the check if the lock is held in 1168 * exclusive mode even for the KA_LOCKED case. 1169 */ 1170 if (slocked || (lk->lk_lock & LK_SHARE)) { 1171 witness_assert(&lk->lock_object, what, file, line); 1172 break; 1173 } 1174 #endif 1175 if (lk->lk_lock == LK_UNLOCKED || 1176 ((lk->lk_lock & LK_SHARE) == 0 && (slocked || 1177 (!lockmgr_xlocked(lk) && !lockmgr_disowned(lk))))) 1178 panic("Lock %s not %slocked @ %s:%d\n", 1179 lk->lock_object.lo_name, slocked ? "share" : "", 1180 file, line); 1181 1182 if ((lk->lk_lock & LK_SHARE) == 0) { 1183 if (lockmgr_recursed(lk)) { 1184 if (what & KA_NOTRECURSED) 1185 panic("Lock %s recursed @ %s:%d\n", 1186 lk->lock_object.lo_name, file, 1187 line); 1188 } else if (what & KA_RECURSED) 1189 panic("Lock %s not recursed @ %s:%d\n", 1190 lk->lock_object.lo_name, file, line); 1191 } 1192 break; 1193 case KA_XLOCKED: 1194 case KA_XLOCKED | KA_NOTRECURSED: 1195 case KA_XLOCKED | KA_RECURSED: 1196 if (!lockmgr_xlocked(lk) && !lockmgr_disowned(lk)) 1197 panic("Lock %s not exclusively locked @ %s:%d\n", 1198 lk->lock_object.lo_name, file, line); 1199 if (lockmgr_recursed(lk)) { 1200 if (what & KA_NOTRECURSED) 1201 panic("Lock %s recursed @ %s:%d\n", 1202 lk->lock_object.lo_name, file, line); 1203 } else if (what & KA_RECURSED) 1204 panic("Lock %s not recursed @ %s:%d\n", 1205 lk->lock_object.lo_name, file, line); 1206 break; 1207 case KA_UNLOCKED: 1208 if (lockmgr_xlocked(lk) || lockmgr_disowned(lk)) 1209 panic("Lock %s exclusively locked @ %s:%d\n", 1210 lk->lock_object.lo_name, file, line); 1211 break; 1212 default: 1213 panic("Unknown lockmgr assertion: %d @ %s:%d\n", what, file, 1214 line); 1215 } 1216 } 1217 #endif 1218 1219 #ifdef DDB 1220 int 1221 lockmgr_chain(struct thread *td, struct thread **ownerp) 1222 { 1223 struct lock *lk; 1224 1225 lk = td->td_wchan; 1226 1227 if (LOCK_CLASS(&lk->lock_object) != &lock_class_lockmgr) 1228 return (0); 1229 db_printf("blocked on lockmgr %s", lk->lock_object.lo_name); 1230 if (lk->lk_lock & LK_SHARE) 1231 db_printf("SHARED (count %ju)\n", 1232 (uintmax_t)LK_SHARERS(lk->lk_lock)); 1233 else 1234 db_printf("EXCL\n"); 1235 *ownerp = lockmgr_xholder(lk); 1236 1237 return (1); 1238 } 1239 1240 static void 1241 db_show_lockmgr(struct lock_object *lock) 1242 { 1243 struct thread *td; 1244 struct lock *lk; 1245 1246 lk = (struct lock *)lock; 1247 1248 db_printf(" state: "); 1249 if (lk->lk_lock == LK_UNLOCKED) 1250 db_printf("UNLOCKED\n"); 1251 else if (lk->lk_lock & LK_SHARE) 1252 db_printf("SLOCK: %ju\n", (uintmax_t)LK_SHARERS(lk->lk_lock)); 1253 else { 1254 td = lockmgr_xholder(lk); 1255 if (td == (struct thread *)LK_KERNPROC) 1256 db_printf("XLOCK: LK_KERNPROC\n"); 1257 else 1258 db_printf("XLOCK: %p (tid %d, pid %d, \"%s\")\n", td, 1259 td->td_tid, td->td_proc->p_pid, 1260 td->td_proc->p_comm); 1261 if (lockmgr_recursed(lk)) 1262 db_printf(" recursed: %d\n", lk->lk_recurse); 1263 } 1264 db_printf(" waiters: "); 1265 switch (lk->lk_lock & LK_ALL_WAITERS) { 1266 case LK_SHARED_WAITERS: 1267 db_printf("shared\n"); 1268 break; 1269 case LK_EXCLUSIVE_WAITERS: 1270 db_printf("exclusive\n"); 1271 break; 1272 case LK_ALL_WAITERS: 1273 db_printf("shared and exclusive\n"); 1274 break; 1275 default: 1276 db_printf("none\n"); 1277 } 1278 db_printf(" spinners: "); 1279 if (lk->lk_lock & LK_EXCLUSIVE_SPINNERS) 1280 db_printf("exclusive\n"); 1281 else 1282 db_printf("none\n"); 1283 } 1284 #endif 1285