FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_mutex.c
1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1998 Berkeley Software Design, Inc. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Berkeley Software Design Inc's name may not be used to endorse or
15 * promote products derived from this software without specific prior
16 * written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 * from BSDI $Id: mutex_witness.c,v 1.1.2.20 2000/04/27 03:10:27 cp Exp $
31 * and BSDI $Id: synch_machdep.c,v 2.3.2.39 2000/04/27 03:10:25 cp Exp $
32 */
33
34 /*
35 * Machine independent bits of mutex implementation.
36 */
37
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40
41 #include "opt_adaptive_mutexes.h"
42 #include "opt_ddb.h"
43 #include "opt_hwpmc_hooks.h"
44 #include "opt_sched.h"
45
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/bus.h>
49 #include <sys/conf.h>
50 #include <sys/kdb.h>
51 #include <sys/kernel.h>
52 #include <sys/ktr.h>
53 #include <sys/lock.h>
54 #include <sys/malloc.h>
55 #include <sys/mutex.h>
56 #include <sys/proc.h>
57 #include <sys/resourcevar.h>
58 #include <sys/sched.h>
59 #include <sys/sbuf.h>
60 #include <sys/smp.h>
61 #include <sys/sysctl.h>
62 #include <sys/turnstile.h>
63 #include <sys/vmmeter.h>
64 #include <sys/lock_profile.h>
65
66 #include <machine/atomic.h>
67 #include <machine/bus.h>
68 #include <machine/cpu.h>
69
70 #include <ddb/ddb.h>
71
72 #include <fs/devfs/devfs_int.h>
73
74 #include <vm/vm.h>
75 #include <vm/vm_extern.h>
76
77 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES)
78 #define ADAPTIVE_MUTEXES
79 #endif
80
81 #ifdef HWPMC_HOOKS
82 #include <sys/pmckern.h>
83 PMC_SOFT_DEFINE( , , lock, failed);
84 #endif
85
86 /*
87 * Return the mutex address when the lock cookie address is provided.
88 * This functionality assumes that struct mtx* have a member named mtx_lock.
89 */
90 #define mtxlock2mtx(c) (__containerof(c, struct mtx, mtx_lock))
91
92 /*
93 * Internal utility macros.
94 */
95 #define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED)
96
97 #define mtx_destroyed(m) ((m)->mtx_lock == MTX_DESTROYED)
98
99 static void assert_mtx(const struct lock_object *lock, int what);
100 #ifdef DDB
101 static void db_show_mtx(const struct lock_object *lock);
102 #endif
103 static void lock_mtx(struct lock_object *lock, uintptr_t how);
104 static void lock_spin(struct lock_object *lock, uintptr_t how);
105 #ifdef KDTRACE_HOOKS
106 static int owner_mtx(const struct lock_object *lock,
107 struct thread **owner);
108 #endif
109 static uintptr_t unlock_mtx(struct lock_object *lock);
110 static uintptr_t unlock_spin(struct lock_object *lock);
111
112 /*
113 * Lock classes for sleep and spin mutexes.
114 */
115 struct lock_class lock_class_mtx_sleep = {
116 .lc_name = "sleep mutex",
117 .lc_flags = LC_SLEEPLOCK | LC_RECURSABLE,
118 .lc_assert = assert_mtx,
119 #ifdef DDB
120 .lc_ddb_show = db_show_mtx,
121 #endif
122 .lc_lock = lock_mtx,
123 .lc_unlock = unlock_mtx,
124 #ifdef KDTRACE_HOOKS
125 .lc_owner = owner_mtx,
126 #endif
127 };
128 struct lock_class lock_class_mtx_spin = {
129 .lc_name = "spin mutex",
130 .lc_flags = LC_SPINLOCK | LC_RECURSABLE,
131 .lc_assert = assert_mtx,
132 #ifdef DDB
133 .lc_ddb_show = db_show_mtx,
134 #endif
135 .lc_lock = lock_spin,
136 .lc_unlock = unlock_spin,
137 #ifdef KDTRACE_HOOKS
138 .lc_owner = owner_mtx,
139 #endif
140 };
141
142 #ifdef ADAPTIVE_MUTEXES
143 static SYSCTL_NODE(_debug, OID_AUTO, mtx, CTLFLAG_RD, NULL, "mtx debugging");
144
145 static struct lock_delay_config __read_frequently mtx_delay;
146
147 SYSCTL_INT(_debug_mtx, OID_AUTO, delay_base, CTLFLAG_RW, &mtx_delay.base,
148 0, "");
149 SYSCTL_INT(_debug_mtx, OID_AUTO, delay_max, CTLFLAG_RW, &mtx_delay.max,
150 0, "");
151
152 LOCK_DELAY_SYSINIT_DEFAULT(mtx_delay);
153 #endif
154
155 static SYSCTL_NODE(_debug, OID_AUTO, mtx_spin, CTLFLAG_RD, NULL,
156 "mtx spin debugging");
157
158 static struct lock_delay_config __read_frequently mtx_spin_delay;
159
160 SYSCTL_INT(_debug_mtx_spin, OID_AUTO, delay_base, CTLFLAG_RW,
161 &mtx_spin_delay.base, 0, "");
162 SYSCTL_INT(_debug_mtx_spin, OID_AUTO, delay_max, CTLFLAG_RW,
163 &mtx_spin_delay.max, 0, "");
164
165 LOCK_DELAY_SYSINIT_DEFAULT(mtx_spin_delay);
166
167 /*
168 * System-wide mutexes
169 */
170 struct mtx blocked_lock;
171 struct mtx __exclusive_cache_line Giant;
172
173 static void _mtx_lock_indefinite_check(struct mtx *, struct lock_delay_arg *);
174
175 void
176 assert_mtx(const struct lock_object *lock, int what)
177 {
178
179 /*
180 * Treat LA_LOCKED as if LA_XLOCKED was asserted.
181 *
182 * Some callers of lc_assert uses LA_LOCKED to indicate that either
183 * a shared lock or write lock was held, while other callers uses
184 * the more strict LA_XLOCKED (used as MA_OWNED).
185 *
186 * Mutex is the only lock class that can not be shared, as a result,
187 * we can reasonably consider the caller really intends to assert
188 * LA_XLOCKED when they are asserting LA_LOCKED on a mutex object.
189 */
190 if (what & LA_LOCKED) {
191 what &= ~LA_LOCKED;
192 what |= LA_XLOCKED;
193 }
194 mtx_assert((const struct mtx *)lock, what);
195 }
196
197 void
198 lock_mtx(struct lock_object *lock, uintptr_t how)
199 {
200
201 mtx_lock((struct mtx *)lock);
202 }
203
204 void
205 lock_spin(struct lock_object *lock, uintptr_t how)
206 {
207
208 panic("spin locks can only use msleep_spin");
209 }
210
211 uintptr_t
212 unlock_mtx(struct lock_object *lock)
213 {
214 struct mtx *m;
215
216 m = (struct mtx *)lock;
217 mtx_assert(m, MA_OWNED | MA_NOTRECURSED);
218 mtx_unlock(m);
219 return (0);
220 }
221
222 uintptr_t
223 unlock_spin(struct lock_object *lock)
224 {
225
226 panic("spin locks can only use msleep_spin");
227 }
228
229 #ifdef KDTRACE_HOOKS
230 int
231 owner_mtx(const struct lock_object *lock, struct thread **owner)
232 {
233 const struct mtx *m;
234 uintptr_t x;
235
236 m = (const struct mtx *)lock;
237 x = m->mtx_lock;
238 *owner = (struct thread *)(x & ~MTX_FLAGMASK);
239 return (*owner != NULL);
240 }
241 #endif
242
243 /*
244 * Function versions of the inlined __mtx_* macros. These are used by
245 * modules and can also be called from assembly language if needed.
246 */
247 void
248 __mtx_lock_flags(volatile uintptr_t *c, int opts, const char *file, int line)
249 {
250 struct mtx *m;
251 uintptr_t tid, v;
252
253 m = mtxlock2mtx(c);
254
255 KASSERT(kdb_active != 0 || SCHEDULER_STOPPED() ||
256 !TD_IS_IDLETHREAD(curthread),
257 ("mtx_lock() by idle thread %p on sleep mutex %s @ %s:%d",
258 curthread, m->lock_object.lo_name, file, line));
259 KASSERT(m->mtx_lock != MTX_DESTROYED,
260 ("mtx_lock() of destroyed mutex @ %s:%d", file, line));
261 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
262 ("mtx_lock() of spin mutex %s @ %s:%d", m->lock_object.lo_name,
263 file, line));
264 WITNESS_CHECKORDER(&m->lock_object, (opts & ~MTX_RECURSE) |
265 LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL);
266
267 tid = (uintptr_t)curthread;
268 v = MTX_UNOWNED;
269 if (!_mtx_obtain_lock_fetch(m, &v, tid))
270 _mtx_lock_sleep(m, v, opts, file, line);
271 else
272 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire,
273 m, 0, 0, file, line);
274 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file,
275 line);
276 WITNESS_LOCK(&m->lock_object, (opts & ~MTX_RECURSE) | LOP_EXCLUSIVE,
277 file, line);
278 TD_LOCKS_INC(curthread);
279 }
280
281 void
282 __mtx_unlock_flags(volatile uintptr_t *c, int opts, const char *file, int line)
283 {
284 struct mtx *m;
285
286 m = mtxlock2mtx(c);
287
288 KASSERT(m->mtx_lock != MTX_DESTROYED,
289 ("mtx_unlock() of destroyed mutex @ %s:%d", file, line));
290 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
291 ("mtx_unlock() of spin mutex %s @ %s:%d", m->lock_object.lo_name,
292 file, line));
293 WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
294 LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file,
295 line);
296 mtx_assert(m, MA_OWNED);
297
298 #ifdef LOCK_PROFILING
299 __mtx_unlock_sleep(c, (uintptr_t)curthread, opts, file, line);
300 #else
301 __mtx_unlock(m, curthread, opts, file, line);
302 #endif
303 TD_LOCKS_DEC(curthread);
304 }
305
306 void
307 __mtx_lock_spin_flags(volatile uintptr_t *c, int opts, const char *file,
308 int line)
309 {
310 struct mtx *m;
311 #ifdef SMP
312 uintptr_t tid, v;
313 #endif
314
315 m = mtxlock2mtx(c);
316
317 KASSERT(m->mtx_lock != MTX_DESTROYED,
318 ("mtx_lock_spin() of destroyed mutex @ %s:%d", file, line));
319 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
320 ("mtx_lock_spin() of sleep mutex %s @ %s:%d",
321 m->lock_object.lo_name, file, line));
322 if (mtx_owned(m))
323 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0 ||
324 (opts & MTX_RECURSE) != 0,
325 ("mtx_lock_spin: recursed on non-recursive mutex %s @ %s:%d\n",
326 m->lock_object.lo_name, file, line));
327 opts &= ~MTX_RECURSE;
328 WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE,
329 file, line, NULL);
330 #ifdef SMP
331 spinlock_enter();
332 tid = (uintptr_t)curthread;
333 v = MTX_UNOWNED;
334 if (!_mtx_obtain_lock_fetch(m, &v, tid))
335 _mtx_lock_spin(m, v, opts, file, line);
336 else
337 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire,
338 m, 0, 0, file, line);
339 #else
340 __mtx_lock_spin(m, curthread, opts, file, line);
341 #endif
342 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file,
343 line);
344 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
345 }
346
347 int
348 __mtx_trylock_spin_flags(volatile uintptr_t *c, int opts, const char *file,
349 int line)
350 {
351 struct mtx *m;
352
353 if (SCHEDULER_STOPPED())
354 return (1);
355
356 m = mtxlock2mtx(c);
357
358 KASSERT(m->mtx_lock != MTX_DESTROYED,
359 ("mtx_trylock_spin() of destroyed mutex @ %s:%d", file, line));
360 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
361 ("mtx_trylock_spin() of sleep mutex %s @ %s:%d",
362 m->lock_object.lo_name, file, line));
363 KASSERT((opts & MTX_RECURSE) == 0,
364 ("mtx_trylock_spin: unsupp. opt MTX_RECURSE on mutex %s @ %s:%d\n",
365 m->lock_object.lo_name, file, line));
366 if (__mtx_trylock_spin(m, curthread, opts, file, line)) {
367 LOCK_LOG_TRY("LOCK", &m->lock_object, opts, 1, file, line);
368 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
369 return (1);
370 }
371 LOCK_LOG_TRY("LOCK", &m->lock_object, opts, 0, file, line);
372 return (0);
373 }
374
375 void
376 __mtx_unlock_spin_flags(volatile uintptr_t *c, int opts, const char *file,
377 int line)
378 {
379 struct mtx *m;
380
381 m = mtxlock2mtx(c);
382
383 KASSERT(m->mtx_lock != MTX_DESTROYED,
384 ("mtx_unlock_spin() of destroyed mutex @ %s:%d", file, line));
385 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
386 ("mtx_unlock_spin() of sleep mutex %s @ %s:%d",
387 m->lock_object.lo_name, file, line));
388 WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
389 LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file,
390 line);
391 mtx_assert(m, MA_OWNED);
392
393 __mtx_unlock_spin(m);
394 }
395
396 /*
397 * The important part of mtx_trylock{,_flags}()
398 * Tries to acquire lock `m.' If this function is called on a mutex that
399 * is already owned, it will recursively acquire the lock.
400 */
401 int
402 _mtx_trylock_flags_int(struct mtx *m, int opts LOCK_FILE_LINE_ARG_DEF)
403 {
404 struct thread *td;
405 uintptr_t tid, v;
406 #ifdef LOCK_PROFILING
407 uint64_t waittime = 0;
408 int contested = 0;
409 #endif
410 int rval;
411 bool recursed;
412
413 td = curthread;
414 tid = (uintptr_t)td;
415 if (SCHEDULER_STOPPED_TD(td))
416 return (1);
417
418 KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(td),
419 ("mtx_trylock() by idle thread %p on sleep mutex %s @ %s:%d",
420 curthread, m->lock_object.lo_name, file, line));
421 KASSERT(m->mtx_lock != MTX_DESTROYED,
422 ("mtx_trylock() of destroyed mutex @ %s:%d", file, line));
423 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
424 ("mtx_trylock() of spin mutex %s @ %s:%d", m->lock_object.lo_name,
425 file, line));
426
427 rval = 1;
428 recursed = false;
429 v = MTX_UNOWNED;
430 for (;;) {
431 if (_mtx_obtain_lock_fetch(m, &v, tid))
432 break;
433 if (v == MTX_UNOWNED)
434 continue;
435 if (v == tid &&
436 ((m->lock_object.lo_flags & LO_RECURSABLE) != 0 ||
437 (opts & MTX_RECURSE) != 0)) {
438 m->mtx_recurse++;
439 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
440 recursed = true;
441 break;
442 }
443 rval = 0;
444 break;
445 }
446
447 opts &= ~MTX_RECURSE;
448
449 LOCK_LOG_TRY("LOCK", &m->lock_object, opts, rval, file, line);
450 if (rval) {
451 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK,
452 file, line);
453 TD_LOCKS_INC(curthread);
454 if (!recursed)
455 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire,
456 m, contested, waittime, file, line);
457 }
458
459 return (rval);
460 }
461
462 int
463 _mtx_trylock_flags_(volatile uintptr_t *c, int opts, const char *file, int line)
464 {
465 struct mtx *m;
466
467 m = mtxlock2mtx(c);
468 return (_mtx_trylock_flags_int(m, opts LOCK_FILE_LINE_ARG));
469 }
470
471 /*
472 * __mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock.
473 *
474 * We call this if the lock is either contested (i.e. we need to go to
475 * sleep waiting for it), or if we need to recurse on it.
476 */
477 #if LOCK_DEBUG > 0
478 void
479 __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v, int opts, const char *file,
480 int line)
481 #else
482 void
483 __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v)
484 #endif
485 {
486 struct thread *td;
487 struct mtx *m;
488 struct turnstile *ts;
489 uintptr_t tid;
490 struct thread *owner;
491 #ifdef LOCK_PROFILING
492 int contested = 0;
493 uint64_t waittime = 0;
494 #endif
495 #if defined(ADAPTIVE_MUTEXES) || defined(KDTRACE_HOOKS)
496 struct lock_delay_arg lda;
497 #endif
498 #ifdef KDTRACE_HOOKS
499 u_int sleep_cnt = 0;
500 int64_t sleep_time = 0;
501 int64_t all_time = 0;
502 #endif
503 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING)
504 int doing_lockprof = 0;
505 #endif
506
507 td = curthread;
508 tid = (uintptr_t)td;
509 m = mtxlock2mtx(c);
510
511 #ifdef KDTRACE_HOOKS
512 if (LOCKSTAT_PROFILE_ENABLED(adaptive__acquire)) {
513 while (v == MTX_UNOWNED) {
514 if (_mtx_obtain_lock_fetch(m, &v, tid))
515 goto out_lockstat;
516 }
517 doing_lockprof = 1;
518 all_time -= lockstat_nsecs(&m->lock_object);
519 }
520 #endif
521 #ifdef LOCK_PROFILING
522 doing_lockprof = 1;
523 #endif
524
525 if (SCHEDULER_STOPPED_TD(td))
526 return;
527
528 #if defined(ADAPTIVE_MUTEXES)
529 lock_delay_arg_init(&lda, &mtx_delay);
530 #elif defined(KDTRACE_HOOKS)
531 lock_delay_arg_init(&lda, NULL);
532 #endif
533
534 if (__predict_false(v == MTX_UNOWNED))
535 v = MTX_READ_VALUE(m);
536
537 if (__predict_false(lv_mtx_owner(v) == td)) {
538 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0 ||
539 (opts & MTX_RECURSE) != 0,
540 ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n",
541 m->lock_object.lo_name, file, line));
542 #if LOCK_DEBUG > 0
543 opts &= ~MTX_RECURSE;
544 #endif
545 m->mtx_recurse++;
546 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
547 if (LOCK_LOG_TEST(&m->lock_object, opts))
548 CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m);
549 return;
550 }
551 #if LOCK_DEBUG > 0
552 opts &= ~MTX_RECURSE;
553 #endif
554
555 #ifdef HWPMC_HOOKS
556 PMC_SOFT_CALL( , , lock, failed);
557 #endif
558 lock_profile_obtain_lock_failed(&m->lock_object,
559 &contested, &waittime);
560 if (LOCK_LOG_TEST(&m->lock_object, opts))
561 CTR4(KTR_LOCK,
562 "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d",
563 m->lock_object.lo_name, (void *)m->mtx_lock, file, line);
564
565 for (;;) {
566 if (v == MTX_UNOWNED) {
567 if (_mtx_obtain_lock_fetch(m, &v, tid))
568 break;
569 continue;
570 }
571 #ifdef KDTRACE_HOOKS
572 lda.spin_cnt++;
573 #endif
574 #ifdef ADAPTIVE_MUTEXES
575 /*
576 * If the owner is running on another CPU, spin until the
577 * owner stops running or the state of the lock changes.
578 */
579 owner = lv_mtx_owner(v);
580 if (TD_IS_RUNNING(owner)) {
581 if (LOCK_LOG_TEST(&m->lock_object, 0))
582 CTR3(KTR_LOCK,
583 "%s: spinning on %p held by %p",
584 __func__, m, owner);
585 KTR_STATE1(KTR_SCHED, "thread",
586 sched_tdname((struct thread *)tid),
587 "spinning", "lockname:\"%s\"",
588 m->lock_object.lo_name);
589 do {
590 lock_delay(&lda);
591 v = MTX_READ_VALUE(m);
592 owner = lv_mtx_owner(v);
593 } while (v != MTX_UNOWNED && TD_IS_RUNNING(owner));
594 KTR_STATE0(KTR_SCHED, "thread",
595 sched_tdname((struct thread *)tid),
596 "running");
597 continue;
598 }
599 #endif
600
601 ts = turnstile_trywait(&m->lock_object);
602 v = MTX_READ_VALUE(m);
603 retry_turnstile:
604
605 /*
606 * Check if the lock has been released while spinning for
607 * the turnstile chain lock.
608 */
609 if (v == MTX_UNOWNED) {
610 turnstile_cancel(ts);
611 continue;
612 }
613
614 #ifdef ADAPTIVE_MUTEXES
615 /*
616 * The current lock owner might have started executing
617 * on another CPU (or the lock could have changed
618 * owners) while we were waiting on the turnstile
619 * chain lock. If so, drop the turnstile lock and try
620 * again.
621 */
622 owner = lv_mtx_owner(v);
623 if (TD_IS_RUNNING(owner)) {
624 turnstile_cancel(ts);
625 continue;
626 }
627 #endif
628
629 /*
630 * If the mutex isn't already contested and a failure occurs
631 * setting the contested bit, the mutex was either released
632 * or the state of the MTX_RECURSED bit changed.
633 */
634 if ((v & MTX_CONTESTED) == 0 &&
635 !atomic_fcmpset_ptr(&m->mtx_lock, &v, v | MTX_CONTESTED)) {
636 goto retry_turnstile;
637 }
638
639 /*
640 * We definitely must sleep for this lock.
641 */
642 mtx_assert(m, MA_NOTOWNED);
643
644 /*
645 * Block on the turnstile.
646 */
647 #ifdef KDTRACE_HOOKS
648 sleep_time -= lockstat_nsecs(&m->lock_object);
649 #endif
650 #ifndef ADAPTIVE_MUTEXES
651 owner = mtx_owner(m);
652 #endif
653 MPASS(owner == mtx_owner(m));
654 turnstile_wait(ts, owner, TS_EXCLUSIVE_QUEUE);
655 #ifdef KDTRACE_HOOKS
656 sleep_time += lockstat_nsecs(&m->lock_object);
657 sleep_cnt++;
658 #endif
659 v = MTX_READ_VALUE(m);
660 }
661 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING)
662 if (__predict_true(!doing_lockprof))
663 return;
664 #endif
665 #ifdef KDTRACE_HOOKS
666 all_time += lockstat_nsecs(&m->lock_object);
667 if (sleep_time)
668 LOCKSTAT_RECORD1(adaptive__block, m, sleep_time);
669
670 /*
671 * Only record the loops spinning and not sleeping.
672 */
673 if (lda.spin_cnt > sleep_cnt)
674 LOCKSTAT_RECORD1(adaptive__spin, m, all_time - sleep_time);
675 out_lockstat:
676 #endif
677 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire, m, contested,
678 waittime, file, line);
679 }
680
681 #ifdef SMP
682 /*
683 * _mtx_lock_spin_cookie: the tougher part of acquiring an MTX_SPIN lock.
684 *
685 * This is only called if we need to actually spin for the lock. Recursion
686 * is handled inline.
687 */
688 #if LOCK_DEBUG > 0
689 void
690 _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v, int opts,
691 const char *file, int line)
692 #else
693 void
694 _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v)
695 #endif
696 {
697 struct mtx *m;
698 struct lock_delay_arg lda;
699 uintptr_t tid;
700 #ifdef LOCK_PROFILING
701 int contested = 0;
702 uint64_t waittime = 0;
703 #endif
704 #ifdef KDTRACE_HOOKS
705 int64_t spin_time = 0;
706 #endif
707 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING)
708 int doing_lockprof = 0;
709 #endif
710
711 tid = (uintptr_t)curthread;
712 m = mtxlock2mtx(c);
713
714 #ifdef KDTRACE_HOOKS
715 if (LOCKSTAT_PROFILE_ENABLED(adaptive__acquire)) {
716 while (v == MTX_UNOWNED) {
717 if (_mtx_obtain_lock_fetch(m, &v, tid))
718 goto out_lockstat;
719 }
720 doing_lockprof = 1;
721 spin_time -= lockstat_nsecs(&m->lock_object);
722 }
723 #endif
724 #ifdef LOCK_PROFILING
725 doing_lockprof = 1;
726 #endif
727
728 if (__predict_false(v == MTX_UNOWNED))
729 v = MTX_READ_VALUE(m);
730
731 if (__predict_false(v == tid)) {
732 m->mtx_recurse++;
733 return;
734 }
735
736 if (SCHEDULER_STOPPED())
737 return;
738
739 lock_delay_arg_init(&lda, &mtx_spin_delay);
740
741 if (LOCK_LOG_TEST(&m->lock_object, opts))
742 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m);
743 KTR_STATE1(KTR_SCHED, "thread", sched_tdname((struct thread *)tid),
744 "spinning", "lockname:\"%s\"", m->lock_object.lo_name);
745
746 #ifdef HWPMC_HOOKS
747 PMC_SOFT_CALL( , , lock, failed);
748 #endif
749 lock_profile_obtain_lock_failed(&m->lock_object, &contested, &waittime);
750
751 for (;;) {
752 if (v == MTX_UNOWNED) {
753 if (_mtx_obtain_lock_fetch(m, &v, tid))
754 break;
755 continue;
756 }
757 /* Give interrupts a chance while we spin. */
758 spinlock_exit();
759 do {
760 if (__predict_true(lda.spin_cnt < 10000000)) {
761 lock_delay(&lda);
762 } else {
763 _mtx_lock_indefinite_check(m, &lda);
764 }
765 v = MTX_READ_VALUE(m);
766 } while (v != MTX_UNOWNED);
767 spinlock_enter();
768 }
769
770 if (LOCK_LOG_TEST(&m->lock_object, opts))
771 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m);
772 KTR_STATE0(KTR_SCHED, "thread", sched_tdname((struct thread *)tid),
773 "running");
774
775 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING)
776 if (__predict_true(!doing_lockprof))
777 return;
778 #endif
779 #ifdef KDTRACE_HOOKS
780 spin_time += lockstat_nsecs(&m->lock_object);
781 if (lda.spin_cnt != 0)
782 LOCKSTAT_RECORD1(spin__spin, m, spin_time);
783 out_lockstat:
784 #endif
785 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, m,
786 contested, waittime, file, line);
787 }
788 #endif /* SMP */
789
790 #ifdef INVARIANTS
791 static void
792 thread_lock_validate(struct mtx *m, int opts, const char *file, int line)
793 {
794
795 KASSERT(m->mtx_lock != MTX_DESTROYED,
796 ("thread_lock() of destroyed mutex @ %s:%d", file, line));
797 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
798 ("thread_lock() of sleep mutex %s @ %s:%d",
799 m->lock_object.lo_name, file, line));
800 if (mtx_owned(m))
801 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0,
802 ("thread_lock: recursed on non-recursive mutex %s @ %s:%d\n",
803 m->lock_object.lo_name, file, line));
804 WITNESS_CHECKORDER(&m->lock_object,
805 opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL);
806 }
807 #else
808 #define thread_lock_validate(m, opts, file, line) do { } while (0)
809 #endif
810
811 #ifndef LOCK_PROFILING
812 #if LOCK_DEBUG > 0
813 void
814 _thread_lock(struct thread *td, int opts, const char *file, int line)
815 #else
816 void
817 _thread_lock(struct thread *td)
818 #endif
819 {
820 struct mtx *m;
821 uintptr_t tid, v;
822
823 tid = (uintptr_t)curthread;
824
825 if (__predict_false(LOCKSTAT_PROFILE_ENABLED(spin__acquire)))
826 goto slowpath_noirq;
827 spinlock_enter();
828 m = td->td_lock;
829 thread_lock_validate(m, 0, file, line);
830 v = MTX_READ_VALUE(m);
831 if (__predict_true(v == MTX_UNOWNED)) {
832 if (__predict_false(!_mtx_obtain_lock(m, tid)))
833 goto slowpath_unlocked;
834 } else if (v == tid) {
835 m->mtx_recurse++;
836 } else
837 goto slowpath_unlocked;
838 if (__predict_true(m == td->td_lock)) {
839 WITNESS_LOCK(&m->lock_object, LOP_EXCLUSIVE, file, line);
840 return;
841 }
842 MPASS(m->mtx_recurse == 0);
843 _mtx_release_lock_quick(m);
844 slowpath_unlocked:
845 spinlock_exit();
846 slowpath_noirq:
847 #if LOCK_DEBUG > 0
848 thread_lock_flags_(td, opts, file, line);
849 #else
850 thread_lock_flags_(td, 0, 0, 0);
851 #endif
852 }
853 #endif
854
855 void
856 thread_lock_flags_(struct thread *td, int opts, const char *file, int line)
857 {
858 struct mtx *m;
859 uintptr_t tid, v;
860 struct lock_delay_arg lda;
861 #ifdef LOCK_PROFILING
862 int contested = 0;
863 uint64_t waittime = 0;
864 #endif
865 #ifdef KDTRACE_HOOKS
866 int64_t spin_time = 0;
867 #endif
868 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING)
869 int doing_lockprof = 1;
870 #endif
871
872 tid = (uintptr_t)curthread;
873
874 if (SCHEDULER_STOPPED()) {
875 /*
876 * Ensure that spinlock sections are balanced even when the
877 * scheduler is stopped, since we may otherwise inadvertently
878 * re-enable interrupts while dumping core.
879 */
880 spinlock_enter();
881 return;
882 }
883
884 lock_delay_arg_init(&lda, &mtx_spin_delay);
885
886 #ifdef HWPMC_HOOKS
887 PMC_SOFT_CALL( , , lock, failed);
888 #endif
889
890 #ifdef LOCK_PROFILING
891 doing_lockprof = 1;
892 #elif defined(KDTRACE_HOOKS)
893 doing_lockprof = lockstat_enabled;
894 if (__predict_false(doing_lockprof))
895 spin_time -= lockstat_nsecs(&td->td_lock->lock_object);
896 #endif
897 spinlock_enter();
898
899 for (;;) {
900 retry:
901 m = td->td_lock;
902 thread_lock_validate(m, opts, file, line);
903 v = MTX_READ_VALUE(m);
904 for (;;) {
905 if (v == MTX_UNOWNED) {
906 if (_mtx_obtain_lock_fetch(m, &v, tid))
907 break;
908 continue;
909 }
910 if (v == tid) {
911 m->mtx_recurse++;
912 MPASS(m == td->td_lock);
913 break;
914 }
915 lock_profile_obtain_lock_failed(&m->lock_object,
916 &contested, &waittime);
917 /* Give interrupts a chance while we spin. */
918 spinlock_exit();
919 do {
920 if (__predict_true(lda.spin_cnt < 10000000)) {
921 lock_delay(&lda);
922 } else {
923 _mtx_lock_indefinite_check(m, &lda);
924 }
925 if (m != td->td_lock) {
926 spinlock_enter();
927 goto retry;
928 }
929 v = MTX_READ_VALUE(m);
930 } while (v != MTX_UNOWNED);
931 spinlock_enter();
932 }
933 if (m == td->td_lock)
934 break;
935 MPASS(m->mtx_recurse == 0);
936 _mtx_release_lock_quick(m);
937 }
938 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file,
939 line);
940 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
941
942 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING)
943 if (__predict_true(!doing_lockprof))
944 return;
945 #endif
946 #ifdef KDTRACE_HOOKS
947 spin_time += lockstat_nsecs(&m->lock_object);
948 #endif
949 if (m->mtx_recurse == 0)
950 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, m,
951 contested, waittime, file, line);
952 #ifdef KDTRACE_HOOKS
953 if (lda.spin_cnt != 0)
954 LOCKSTAT_RECORD1(thread__spin, m, spin_time);
955 #endif
956 }
957
958 struct mtx *
959 thread_lock_block(struct thread *td)
960 {
961 struct mtx *lock;
962
963 THREAD_LOCK_ASSERT(td, MA_OWNED);
964 lock = td->td_lock;
965 td->td_lock = &blocked_lock;
966 mtx_unlock_spin(lock);
967
968 return (lock);
969 }
970
971 void
972 thread_lock_unblock(struct thread *td, struct mtx *new)
973 {
974 mtx_assert(new, MA_OWNED);
975 MPASS(td->td_lock == &blocked_lock);
976 atomic_store_rel_ptr((volatile void *)&td->td_lock, (uintptr_t)new);
977 }
978
979 void
980 thread_lock_set(struct thread *td, struct mtx *new)
981 {
982 struct mtx *lock;
983
984 mtx_assert(new, MA_OWNED);
985 THREAD_LOCK_ASSERT(td, MA_OWNED);
986 lock = td->td_lock;
987 td->td_lock = new;
988 mtx_unlock_spin(lock);
989 }
990
991 /*
992 * __mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock.
993 *
994 * We are only called here if the lock is recursed, contested (i.e. we
995 * need to wake up a blocked thread) or lockstat probe is active.
996 */
997 #if LOCK_DEBUG > 0
998 void
999 __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v, int opts,
1000 const char *file, int line)
1001 #else
1002 void
1003 __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v)
1004 #endif
1005 {
1006 struct mtx *m;
1007 struct turnstile *ts;
1008 uintptr_t tid;
1009
1010 if (SCHEDULER_STOPPED())
1011 return;
1012
1013 tid = (uintptr_t)curthread;
1014 m = mtxlock2mtx(c);
1015
1016 if (__predict_false(v == tid))
1017 v = MTX_READ_VALUE(m);
1018
1019 if (__predict_false(v & MTX_RECURSED)) {
1020 if (--(m->mtx_recurse) == 0)
1021 atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED);
1022 if (LOCK_LOG_TEST(&m->lock_object, opts))
1023 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m);
1024 return;
1025 }
1026
1027 LOCKSTAT_PROFILE_RELEASE_LOCK(adaptive__release, m);
1028 if (v == tid && _mtx_release_lock(m, tid))
1029 return;
1030
1031 /*
1032 * We have to lock the chain before the turnstile so this turnstile
1033 * can be removed from the hash list if it is empty.
1034 */
1035 turnstile_chain_lock(&m->lock_object);
1036 _mtx_release_lock_quick(m);
1037 ts = turnstile_lookup(&m->lock_object);
1038 MPASS(ts != NULL);
1039 if (LOCK_LOG_TEST(&m->lock_object, opts))
1040 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m);
1041 turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE);
1042
1043 /*
1044 * This turnstile is now no longer associated with the mutex. We can
1045 * unlock the chain lock so a new turnstile may take it's place.
1046 */
1047 turnstile_unpend(ts);
1048 turnstile_chain_unlock(&m->lock_object);
1049 }
1050
1051 /*
1052 * All the unlocking of MTX_SPIN locks is done inline.
1053 * See the __mtx_unlock_spin() macro for the details.
1054 */
1055
1056 /*
1057 * The backing function for the INVARIANTS-enabled mtx_assert()
1058 */
1059 #ifdef INVARIANT_SUPPORT
1060 void
1061 __mtx_assert(const volatile uintptr_t *c, int what, const char *file, int line)
1062 {
1063 const struct mtx *m;
1064
1065 if (panicstr != NULL || dumping || SCHEDULER_STOPPED())
1066 return;
1067
1068 m = mtxlock2mtx(c);
1069
1070 switch (what) {
1071 case MA_OWNED:
1072 case MA_OWNED | MA_RECURSED:
1073 case MA_OWNED | MA_NOTRECURSED:
1074 if (!mtx_owned(m))
1075 panic("mutex %s not owned at %s:%d",
1076 m->lock_object.lo_name, file, line);
1077 if (mtx_recursed(m)) {
1078 if ((what & MA_NOTRECURSED) != 0)
1079 panic("mutex %s recursed at %s:%d",
1080 m->lock_object.lo_name, file, line);
1081 } else if ((what & MA_RECURSED) != 0) {
1082 panic("mutex %s unrecursed at %s:%d",
1083 m->lock_object.lo_name, file, line);
1084 }
1085 break;
1086 case MA_NOTOWNED:
1087 if (mtx_owned(m))
1088 panic("mutex %s owned at %s:%d",
1089 m->lock_object.lo_name, file, line);
1090 break;
1091 default:
1092 panic("unknown mtx_assert at %s:%d", file, line);
1093 }
1094 }
1095 #endif
1096
1097 /*
1098 * General init routine used by the MTX_SYSINIT() macro.
1099 */
1100 void
1101 mtx_sysinit(void *arg)
1102 {
1103 struct mtx_args *margs = arg;
1104
1105 mtx_init((struct mtx *)margs->ma_mtx, margs->ma_desc, NULL,
1106 margs->ma_opts);
1107 }
1108
1109 /*
1110 * Mutex initialization routine; initialize lock `m' of type contained in
1111 * `opts' with options contained in `opts' and name `name.' The optional
1112 * lock type `type' is used as a general lock category name for use with
1113 * witness.
1114 */
1115 void
1116 _mtx_init(volatile uintptr_t *c, const char *name, const char *type, int opts)
1117 {
1118 struct mtx *m;
1119 struct lock_class *class;
1120 int flags;
1121
1122 m = mtxlock2mtx(c);
1123
1124 MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE |
1125 MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE | MTX_NEW)) == 0);
1126 ASSERT_ATOMIC_LOAD_PTR(m->mtx_lock,
1127 ("%s: mtx_lock not aligned for %s: %p", __func__, name,
1128 &m->mtx_lock));
1129
1130 /* Determine lock class and lock flags. */
1131 if (opts & MTX_SPIN)
1132 class = &lock_class_mtx_spin;
1133 else
1134 class = &lock_class_mtx_sleep;
1135 flags = 0;
1136 if (opts & MTX_QUIET)
1137 flags |= LO_QUIET;
1138 if (opts & MTX_RECURSE)
1139 flags |= LO_RECURSABLE;
1140 if ((opts & MTX_NOWITNESS) == 0)
1141 flags |= LO_WITNESS;
1142 if (opts & MTX_DUPOK)
1143 flags |= LO_DUPOK;
1144 if (opts & MTX_NOPROFILE)
1145 flags |= LO_NOPROFILE;
1146 if (opts & MTX_NEW)
1147 flags |= LO_NEW;
1148
1149 /* Initialize mutex. */
1150 lock_init(&m->lock_object, class, name, type, flags);
1151
1152 m->mtx_lock = MTX_UNOWNED;
1153 m->mtx_recurse = 0;
1154 }
1155
1156 /*
1157 * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be
1158 * passed in as a flag here because if the corresponding mtx_init() was
1159 * called with MTX_QUIET set, then it will already be set in the mutex's
1160 * flags.
1161 */
1162 void
1163 _mtx_destroy(volatile uintptr_t *c)
1164 {
1165 struct mtx *m;
1166
1167 m = mtxlock2mtx(c);
1168
1169 if (!mtx_owned(m))
1170 MPASS(mtx_unowned(m));
1171 else {
1172 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0);
1173
1174 /* Perform the non-mtx related part of mtx_unlock_spin(). */
1175 if (LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin)
1176 spinlock_exit();
1177 else
1178 TD_LOCKS_DEC(curthread);
1179
1180 lock_profile_release_lock(&m->lock_object);
1181 /* Tell witness this isn't locked to make it happy. */
1182 WITNESS_UNLOCK(&m->lock_object, LOP_EXCLUSIVE, __FILE__,
1183 __LINE__);
1184 }
1185
1186 m->mtx_lock = MTX_DESTROYED;
1187 lock_destroy(&m->lock_object);
1188 }
1189
1190 /*
1191 * Intialize the mutex code and system mutexes. This is called from the MD
1192 * startup code prior to mi_startup(). The per-CPU data space needs to be
1193 * setup before this is called.
1194 */
1195 void
1196 mutex_init(void)
1197 {
1198
1199 /* Setup turnstiles so that sleep mutexes work. */
1200 init_turnstiles();
1201
1202 /*
1203 * Initialize mutexes.
1204 */
1205 mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE);
1206 mtx_init(&blocked_lock, "blocked lock", NULL, MTX_SPIN);
1207 blocked_lock.mtx_lock = 0xdeadc0de; /* Always blocked. */
1208 mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK);
1209 mtx_init(&proc0.p_slock, "process slock", NULL, MTX_SPIN);
1210 mtx_init(&proc0.p_statmtx, "pstatl", NULL, MTX_SPIN);
1211 mtx_init(&proc0.p_itimmtx, "pitiml", NULL, MTX_SPIN);
1212 mtx_init(&proc0.p_profmtx, "pprofl", NULL, MTX_SPIN);
1213 mtx_init(&devmtx, "cdev", NULL, MTX_DEF);
1214 mtx_lock(&Giant);
1215 }
1216
1217 static void __noinline
1218 _mtx_lock_indefinite_check(struct mtx *m, struct lock_delay_arg *ldap)
1219 {
1220 struct thread *td;
1221
1222 ldap->spin_cnt++;
1223 if (ldap->spin_cnt < 60000000 || kdb_active || panicstr != NULL)
1224 cpu_lock_delay();
1225 else {
1226 td = mtx_owner(m);
1227
1228 /* If the mutex is unlocked, try again. */
1229 if (td == NULL)
1230 return;
1231
1232 printf( "spin lock %p (%s) held by %p (tid %d) too long\n",
1233 m, m->lock_object.lo_name, td, td->td_tid);
1234 #ifdef WITNESS
1235 witness_display_spinlock(&m->lock_object, td, printf);
1236 #endif
1237 panic("spin lock held too long");
1238 }
1239 cpu_spinwait();
1240 }
1241
1242 void
1243 mtx_spin_wait_unlocked(struct mtx *m)
1244 {
1245 struct lock_delay_arg lda;
1246
1247 KASSERT(m->mtx_lock != MTX_DESTROYED,
1248 ("%s() of destroyed mutex %p", __func__, m));
1249 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
1250 ("%s() of sleep mutex %p (%s)", __func__, m,
1251 m->lock_object.lo_name));
1252 KASSERT(!mtx_owned(m), ("%s() waiting on myself on lock %p (%s)", __func__, m,
1253 m->lock_object.lo_name));
1254
1255 lda.spin_cnt = 0;
1256
1257 while (atomic_load_acq_ptr(&m->mtx_lock) != MTX_UNOWNED) {
1258 if (__predict_true(lda.spin_cnt < 10000000)) {
1259 cpu_spinwait();
1260 lda.spin_cnt++;
1261 } else {
1262 _mtx_lock_indefinite_check(m, &lda);
1263 }
1264 }
1265 }
1266
1267 #ifdef DDB
1268 void
1269 db_show_mtx(const struct lock_object *lock)
1270 {
1271 struct thread *td;
1272 const struct mtx *m;
1273
1274 m = (const struct mtx *)lock;
1275
1276 db_printf(" flags: {");
1277 if (LOCK_CLASS(lock) == &lock_class_mtx_spin)
1278 db_printf("SPIN");
1279 else
1280 db_printf("DEF");
1281 if (m->lock_object.lo_flags & LO_RECURSABLE)
1282 db_printf(", RECURSE");
1283 if (m->lock_object.lo_flags & LO_DUPOK)
1284 db_printf(", DUPOK");
1285 db_printf("}\n");
1286 db_printf(" state: {");
1287 if (mtx_unowned(m))
1288 db_printf("UNOWNED");
1289 else if (mtx_destroyed(m))
1290 db_printf("DESTROYED");
1291 else {
1292 db_printf("OWNED");
1293 if (m->mtx_lock & MTX_CONTESTED)
1294 db_printf(", CONTESTED");
1295 if (m->mtx_lock & MTX_RECURSED)
1296 db_printf(", RECURSED");
1297 }
1298 db_printf("}\n");
1299 if (!mtx_unowned(m) && !mtx_destroyed(m)) {
1300 td = mtx_owner(m);
1301 db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td,
1302 td->td_tid, td->td_proc->p_pid, td->td_name);
1303 if (mtx_recursed(m))
1304 db_printf(" recursed: %d\n", m->mtx_recurse);
1305 }
1306 }
1307 #endif
Cache object: 78a80ee157909c16faf3abea385c3a52
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