2 * Copyright (c) 1998 Berkeley Software Design, Inc. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
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
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
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 $
33 * Machine independent bits of mutex implementation.
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
39 #include "opt_adaptive_mutexes.h"
41 #include "opt_global.h"
42 #include "opt_hwpmc_hooks.h"
43 #include "opt_kdtrace.h"
44 #include "opt_sched.h"
46 #include <sys/param.h>
47 #include <sys/systm.h>
51 #include <sys/kernel.h>
54 #include <sys/malloc.h>
55 #include <sys/mutex.h>
57 #include <sys/resourcevar.h>
58 #include <sys/sched.h>
60 #include <sys/sysctl.h>
61 #include <sys/turnstile.h>
62 #include <sys/vmmeter.h>
63 #include <sys/lock_profile.h>
65 #include <machine/atomic.h>
66 #include <machine/bus.h>
67 #include <machine/cpu.h>
71 #include <fs/devfs/devfs_int.h>
74 #include <vm/vm_extern.h>
76 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES)
77 #define ADAPTIVE_MUTEXES
81 #include <sys/pmckern.h>
82 PMC_SOFT_DEFINE( , , lock, failed);
86 * Internal utility macros.
88 #define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED)
90 #define mtx_destroyed(m) ((m)->mtx_lock == MTX_DESTROYED)
92 #define mtx_owner(m) ((struct thread *)((m)->mtx_lock & ~MTX_FLAGMASK))
94 static void assert_mtx(struct lock_object *lock, int what);
96 static void db_show_mtx(struct lock_object *lock);
98 static void lock_mtx(struct lock_object *lock, int how);
99 static void lock_spin(struct lock_object *lock, int how);
101 static int owner_mtx(struct lock_object *lock, struct thread **owner);
103 static int unlock_mtx(struct lock_object *lock);
104 static int unlock_spin(struct lock_object *lock);
107 * Lock classes for sleep and spin mutexes.
109 struct lock_class lock_class_mtx_sleep = {
110 .lc_name = "sleep mutex",
111 .lc_flags = LC_SLEEPLOCK | LC_RECURSABLE,
112 .lc_assert = assert_mtx,
114 .lc_ddb_show = db_show_mtx,
117 .lc_unlock = unlock_mtx,
119 .lc_owner = owner_mtx,
122 struct lock_class lock_class_mtx_spin = {
123 .lc_name = "spin mutex",
124 .lc_flags = LC_SPINLOCK | LC_RECURSABLE,
125 .lc_assert = assert_mtx,
127 .lc_ddb_show = db_show_mtx,
129 .lc_lock = lock_spin,
130 .lc_unlock = unlock_spin,
132 .lc_owner = owner_mtx,
137 * System-wide mutexes
139 struct mtx blocked_lock;
143 assert_mtx(struct lock_object *lock, int what)
146 mtx_assert((struct mtx *)lock, what);
150 lock_mtx(struct lock_object *lock, int how)
153 mtx_lock((struct mtx *)lock);
157 lock_spin(struct lock_object *lock, int how)
160 panic("spin locks can only use msleep_spin");
164 unlock_mtx(struct lock_object *lock)
168 m = (struct mtx *)lock;
169 mtx_assert(m, MA_OWNED | MA_NOTRECURSED);
175 unlock_spin(struct lock_object *lock)
178 panic("spin locks can only use msleep_spin");
183 owner_mtx(struct lock_object *lock, struct thread **owner)
185 struct mtx *m = (struct mtx *)lock;
187 *owner = mtx_owner(m);
188 return (mtx_unowned(m) == 0);
193 * Function versions of the inlined __mtx_* macros. These are used by
194 * modules and can also be called from assembly language if needed.
197 _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line)
200 if (SCHEDULER_STOPPED())
202 KASSERT(m->mtx_lock != MTX_DESTROYED,
203 ("mtx_lock() of destroyed mutex @ %s:%d", file, line));
204 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
205 ("mtx_lock() of spin mutex %s @ %s:%d", m->lock_object.lo_name,
207 WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE,
210 __mtx_lock(m, curthread, opts, file, line);
211 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file,
213 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
214 curthread->td_locks++;
218 _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
221 if (SCHEDULER_STOPPED())
223 KASSERT(m->mtx_lock != MTX_DESTROYED,
224 ("mtx_unlock() of destroyed mutex @ %s:%d", file, line));
225 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
226 ("mtx_unlock() of spin mutex %s @ %s:%d", m->lock_object.lo_name,
228 curthread->td_locks--;
229 WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
230 LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file,
232 mtx_assert(m, MA_OWNED);
234 if (m->mtx_recurse == 0)
235 LOCKSTAT_PROFILE_RELEASE_LOCK(LS_MTX_UNLOCK_RELEASE, m);
236 __mtx_unlock(m, curthread, opts, file, line);
240 _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file, int line)
243 if (SCHEDULER_STOPPED())
245 KASSERT(m->mtx_lock != MTX_DESTROYED,
246 ("mtx_lock_spin() of destroyed mutex @ %s:%d", file, line));
247 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
248 ("mtx_lock_spin() of sleep mutex %s @ %s:%d",
249 m->lock_object.lo_name, file, line));
251 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0,
252 ("mtx_lock_spin: recursed on non-recursive mutex %s @ %s:%d\n",
253 m->lock_object.lo_name, file, line));
254 WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE,
256 __mtx_lock_spin(m, curthread, opts, file, line);
257 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file,
259 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
263 _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file, int line)
266 if (SCHEDULER_STOPPED())
268 KASSERT(m->mtx_lock != MTX_DESTROYED,
269 ("mtx_unlock_spin() of destroyed mutex @ %s:%d", file, line));
270 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
271 ("mtx_unlock_spin() of sleep mutex %s @ %s:%d",
272 m->lock_object.lo_name, file, line));
273 WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
274 LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file,
276 mtx_assert(m, MA_OWNED);
278 __mtx_unlock_spin(m);
282 * The important part of mtx_trylock{,_flags}()
283 * Tries to acquire lock `m.' If this function is called on a mutex that
284 * is already owned, it will recursively acquire the lock.
287 _mtx_trylock(struct mtx *m, int opts, const char *file, int line)
289 #ifdef LOCK_PROFILING
290 uint64_t waittime = 0;
295 if (SCHEDULER_STOPPED())
298 KASSERT(m->mtx_lock != MTX_DESTROYED,
299 ("mtx_trylock() of destroyed mutex @ %s:%d", file, line));
300 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
301 ("mtx_trylock() of spin mutex %s @ %s:%d", m->lock_object.lo_name,
304 if (mtx_owned(m) && (m->lock_object.lo_flags & LO_RECURSABLE) != 0) {
306 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
309 rval = _mtx_obtain_lock(m, (uintptr_t)curthread);
311 LOCK_LOG_TRY("LOCK", &m->lock_object, opts, rval, file, line);
313 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK,
315 curthread->td_locks++;
316 if (m->mtx_recurse == 0)
317 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_LOCK_ACQUIRE,
318 m, contested, waittime, file, line);
326 * _mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock.
328 * We call this if the lock is either contested (i.e. we need to go to
329 * sleep waiting for it), or if we need to recurse on it.
332 _mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts, const char *file,
335 struct turnstile *ts;
337 #ifdef ADAPTIVE_MUTEXES
338 volatile struct thread *owner;
343 #ifdef LOCK_PROFILING
345 uint64_t waittime = 0;
348 uint64_t spin_cnt = 0;
349 uint64_t sleep_cnt = 0;
350 int64_t sleep_time = 0;
353 if (SCHEDULER_STOPPED())
357 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0,
358 ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n",
359 m->lock_object.lo_name, file, line));
361 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
362 if (LOCK_LOG_TEST(&m->lock_object, opts))
363 CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m);
368 PMC_SOFT_CALL( , , lock, failed);
370 lock_profile_obtain_lock_failed(&m->lock_object,
371 &contested, &waittime);
372 if (LOCK_LOG_TEST(&m->lock_object, opts))
374 "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d",
375 m->lock_object.lo_name, (void *)m->mtx_lock, file, line);
377 while (!_mtx_obtain_lock(m, tid)) {
381 #ifdef ADAPTIVE_MUTEXES
383 * If the owner is running on another CPU, spin until the
384 * owner stops running or the state of the lock changes.
387 if (v != MTX_UNOWNED) {
388 owner = (struct thread *)(v & ~MTX_FLAGMASK);
389 if (TD_IS_RUNNING(owner)) {
390 if (LOCK_LOG_TEST(&m->lock_object, 0))
392 "%s: spinning on %p held by %p",
394 while (mtx_owner(m) == owner &&
395 TD_IS_RUNNING(owner)) {
406 ts = turnstile_trywait(&m->lock_object);
410 * Check if the lock has been released while spinning for
411 * the turnstile chain lock.
413 if (v == MTX_UNOWNED) {
414 turnstile_cancel(ts);
418 #ifdef ADAPTIVE_MUTEXES
420 * The current lock owner might have started executing
421 * on another CPU (or the lock could have changed
422 * owners) while we were waiting on the turnstile
423 * chain lock. If so, drop the turnstile lock and try
426 owner = (struct thread *)(v & ~MTX_FLAGMASK);
427 if (TD_IS_RUNNING(owner)) {
428 turnstile_cancel(ts);
434 * If the mutex isn't already contested and a failure occurs
435 * setting the contested bit, the mutex was either released
436 * or the state of the MTX_RECURSED bit changed.
438 if ((v & MTX_CONTESTED) == 0 &&
439 !atomic_cmpset_ptr(&m->mtx_lock, v, v | MTX_CONTESTED)) {
440 turnstile_cancel(ts);
445 * We definitely must sleep for this lock.
447 mtx_assert(m, MA_NOTOWNED);
452 "contention: %p at %s:%d wants %s, taken by %s:%d",
453 (void *)tid, file, line, m->lock_object.lo_name,
454 WITNESS_FILE(&m->lock_object),
455 WITNESS_LINE(&m->lock_object));
461 * Block on the turnstile.
464 sleep_time -= lockstat_nsecs();
466 turnstile_wait(ts, mtx_owner(m), TS_EXCLUSIVE_QUEUE);
468 sleep_time += lockstat_nsecs();
475 "contention end: %s acquired by %p at %s:%d",
476 m->lock_object.lo_name, (void *)tid, file, line);
479 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_LOCK_ACQUIRE, m, contested,
480 waittime, file, line);
483 LOCKSTAT_RECORD1(LS_MTX_LOCK_BLOCK, m, sleep_time);
486 * Only record the loops spinning and not sleeping.
488 if (spin_cnt > sleep_cnt)
489 LOCKSTAT_RECORD1(LS_MTX_LOCK_SPIN, m, (spin_cnt - sleep_cnt));
494 _mtx_lock_spin_failed(struct mtx *m)
500 /* If the mutex is unlocked, try again. */
504 printf( "spin lock %p (%s) held by %p (tid %d) too long\n",
505 m, m->lock_object.lo_name, td, td->td_tid);
507 witness_display_spinlock(&m->lock_object, td, printf);
509 panic("spin lock held too long");
514 * _mtx_lock_spin: the tougher part of acquiring an MTX_SPIN lock.
516 * This is only called if we need to actually spin for the lock. Recursion
520 _mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts, const char *file,
524 #ifdef LOCK_PROFILING
526 uint64_t waittime = 0;
529 if (SCHEDULER_STOPPED())
532 if (LOCK_LOG_TEST(&m->lock_object, opts))
533 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m);
536 PMC_SOFT_CALL( , , lock, failed);
538 lock_profile_obtain_lock_failed(&m->lock_object, &contested, &waittime);
539 while (!_mtx_obtain_lock(m, tid)) {
541 /* Give interrupts a chance while we spin. */
543 while (m->mtx_lock != MTX_UNOWNED) {
544 if (i++ < 10000000) {
548 if (i < 60000000 || kdb_active || panicstr != NULL)
551 _mtx_lock_spin_failed(m);
557 if (LOCK_LOG_TEST(&m->lock_object, opts))
558 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m);
560 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE, m,
561 contested, waittime, (file), (line));
562 LOCKSTAT_RECORD1(LS_MTX_SPIN_LOCK_SPIN, m, i);
567 _thread_lock_flags(struct thread *td, int opts, const char *file, int line)
572 #ifdef LOCK_PROFILING
574 uint64_t waittime = 0;
577 uint64_t spin_cnt = 0;
581 tid = (uintptr_t)curthread;
583 if (SCHEDULER_STOPPED())
590 KASSERT(m->mtx_lock != MTX_DESTROYED,
591 ("thread_lock() of destroyed mutex @ %s:%d", file, line));
592 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
593 ("thread_lock() of sleep mutex %s @ %s:%d",
594 m->lock_object.lo_name, file, line));
596 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0,
597 ("thread_lock: recursed on non-recursive mutex %s @ %s:%d\n",
598 m->lock_object.lo_name, file, line));
599 WITNESS_CHECKORDER(&m->lock_object,
600 opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL);
601 while (!_mtx_obtain_lock(m, tid)) {
605 if (m->mtx_lock == tid) {
610 PMC_SOFT_CALL( , , lock, failed);
612 lock_profile_obtain_lock_failed(&m->lock_object,
613 &contested, &waittime);
614 /* Give interrupts a chance while we spin. */
616 while (m->mtx_lock != MTX_UNOWNED) {
619 else if (i < 60000000 ||
620 kdb_active || panicstr != NULL)
623 _mtx_lock_spin_failed(m);
625 if (m != td->td_lock)
630 if (m == td->td_lock)
632 __mtx_unlock_spin(m); /* does spinlock_exit() */
637 if (m->mtx_recurse == 0)
638 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE,
639 m, contested, waittime, (file), (line));
640 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file,
642 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
643 LOCKSTAT_RECORD1(LS_THREAD_LOCK_SPIN, m, spin_cnt);
647 thread_lock_block(struct thread *td)
651 THREAD_LOCK_ASSERT(td, MA_OWNED);
653 td->td_lock = &blocked_lock;
654 mtx_unlock_spin(lock);
660 thread_lock_unblock(struct thread *td, struct mtx *new)
662 mtx_assert(new, MA_OWNED);
663 MPASS(td->td_lock == &blocked_lock);
664 atomic_store_rel_ptr((volatile void *)&td->td_lock, (uintptr_t)new);
668 thread_lock_set(struct thread *td, struct mtx *new)
672 mtx_assert(new, MA_OWNED);
673 THREAD_LOCK_ASSERT(td, MA_OWNED);
676 mtx_unlock_spin(lock);
680 * _mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock.
682 * We are only called here if the lock is recursed or contested (i.e. we
683 * need to wake up a blocked thread).
686 _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line)
688 struct turnstile *ts;
690 if (SCHEDULER_STOPPED())
693 if (mtx_recursed(m)) {
694 if (--(m->mtx_recurse) == 0)
695 atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED);
696 if (LOCK_LOG_TEST(&m->lock_object, opts))
697 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m);
702 * We have to lock the chain before the turnstile so this turnstile
703 * can be removed from the hash list if it is empty.
705 turnstile_chain_lock(&m->lock_object);
706 ts = turnstile_lookup(&m->lock_object);
707 if (LOCK_LOG_TEST(&m->lock_object, opts))
708 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m);
710 turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE);
711 _mtx_release_lock_quick(m);
714 * This turnstile is now no longer associated with the mutex. We can
715 * unlock the chain lock so a new turnstile may take it's place.
717 turnstile_unpend(ts, TS_EXCLUSIVE_LOCK);
718 turnstile_chain_unlock(&m->lock_object);
722 * All the unlocking of MTX_SPIN locks is done inline.
723 * See the __mtx_unlock_spin() macro for the details.
727 * The backing function for the INVARIANTS-enabled mtx_assert()
729 #ifdef INVARIANT_SUPPORT
731 _mtx_assert(struct mtx *m, int what, const char *file, int line)
734 if (panicstr != NULL || dumping)
738 case MA_OWNED | MA_RECURSED:
739 case MA_OWNED | MA_NOTRECURSED:
741 panic("mutex %s not owned at %s:%d",
742 m->lock_object.lo_name, file, line);
743 if (mtx_recursed(m)) {
744 if ((what & MA_NOTRECURSED) != 0)
745 panic("mutex %s recursed at %s:%d",
746 m->lock_object.lo_name, file, line);
747 } else if ((what & MA_RECURSED) != 0) {
748 panic("mutex %s unrecursed at %s:%d",
749 m->lock_object.lo_name, file, line);
754 panic("mutex %s owned at %s:%d",
755 m->lock_object.lo_name, file, line);
758 panic("unknown mtx_assert at %s:%d", file, line);
764 * The MUTEX_DEBUG-enabled mtx_validate()
766 * Most of these checks have been moved off into the LO_INITIALIZED flag
767 * maintained by the witness code.
771 void mtx_validate(struct mtx *);
774 mtx_validate(struct mtx *m)
778 * XXX: When kernacc() does not require Giant we can reenable this check
782 * Can't call kernacc() from early init386(), especially when
783 * initializing Giant mutex, because some stuff in kernacc()
784 * requires Giant itself.
787 if (!kernacc((caddr_t)m, sizeof(m),
788 VM_PROT_READ | VM_PROT_WRITE))
789 panic("Can't read and write to mutex %p", m);
795 * General init routine used by the MTX_SYSINIT() macro.
798 mtx_sysinit(void *arg)
800 struct mtx_args *margs = arg;
802 mtx_init(margs->ma_mtx, margs->ma_desc, NULL, margs->ma_opts);
806 * Mutex initialization routine; initialize lock `m' of type contained in
807 * `opts' with options contained in `opts' and name `name.' The optional
808 * lock type `type' is used as a general lock category name for use with
812 mtx_init(struct mtx *m, const char *name, const char *type, int opts)
814 struct lock_class *class;
817 MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE |
818 MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE)) == 0);
819 ASSERT_ATOMIC_LOAD_PTR(m->mtx_lock,
820 ("%s: mtx_lock not aligned for %s: %p", __func__, name,
824 /* Diagnostic and error correction */
828 /* Determine lock class and lock flags. */
830 class = &lock_class_mtx_spin;
832 class = &lock_class_mtx_sleep;
834 if (opts & MTX_QUIET)
836 if (opts & MTX_RECURSE)
837 flags |= LO_RECURSABLE;
838 if ((opts & MTX_NOWITNESS) == 0)
840 if (opts & MTX_DUPOK)
842 if (opts & MTX_NOPROFILE)
843 flags |= LO_NOPROFILE;
845 /* Initialize mutex. */
846 m->mtx_lock = MTX_UNOWNED;
849 lock_init(&m->lock_object, class, name, type, flags);
853 * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be
854 * passed in as a flag here because if the corresponding mtx_init() was
855 * called with MTX_QUIET set, then it will already be set in the mutex's
859 mtx_destroy(struct mtx *m)
863 MPASS(mtx_unowned(m));
865 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0);
867 /* Perform the non-mtx related part of mtx_unlock_spin(). */
868 if (LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin)
871 curthread->td_locks--;
873 lock_profile_release_lock(&m->lock_object);
874 /* Tell witness this isn't locked to make it happy. */
875 WITNESS_UNLOCK(&m->lock_object, LOP_EXCLUSIVE, __FILE__,
879 m->mtx_lock = MTX_DESTROYED;
880 lock_destroy(&m->lock_object);
884 * Intialize the mutex code and system mutexes. This is called from the MD
885 * startup code prior to mi_startup(). The per-CPU data space needs to be
886 * setup before this is called.
892 /* Setup turnstiles so that sleep mutexes work. */
896 * Initialize mutexes.
898 mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE);
899 mtx_init(&blocked_lock, "blocked lock", NULL, MTX_SPIN);
900 blocked_lock.mtx_lock = 0xdeadc0de; /* Always blocked. */
901 mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK);
902 mtx_init(&proc0.p_slock, "process slock", NULL, MTX_SPIN | MTX_RECURSE);
903 mtx_init(&devmtx, "cdev", NULL, MTX_DEF);
909 db_show_mtx(struct lock_object *lock)
914 m = (struct mtx *)lock;
916 db_printf(" flags: {");
917 if (LOCK_CLASS(lock) == &lock_class_mtx_spin)
921 if (m->lock_object.lo_flags & LO_RECURSABLE)
922 db_printf(", RECURSE");
923 if (m->lock_object.lo_flags & LO_DUPOK)
924 db_printf(", DUPOK");
926 db_printf(" state: {");
928 db_printf("UNOWNED");
929 else if (mtx_destroyed(m))
930 db_printf("DESTROYED");
933 if (m->mtx_lock & MTX_CONTESTED)
934 db_printf(", CONTESTED");
935 if (m->mtx_lock & MTX_RECURSED)
936 db_printf(", RECURSED");
939 if (!mtx_unowned(m) && !mtx_destroyed(m)) {
941 db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td,
942 td->td_tid, td->td_proc->p_pid, td->td_name);
944 db_printf(" recursed: %d\n", m->mtx_recurse);