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(kdb_active != 0 || !TD_IS_IDLETHREAD(curthread),
203 ("mtx_lock() by idle thread %p on sleep mutex %s @ %s:%d",
204 curthread, m->lock_object.lo_name, file, line));
205 KASSERT(m->mtx_lock != MTX_DESTROYED,
206 ("mtx_lock() of destroyed mutex @ %s:%d", file, line));
207 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
208 ("mtx_lock() of spin mutex %s @ %s:%d", m->lock_object.lo_name,
210 WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE,
213 __mtx_lock(m, curthread, opts, file, line);
214 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file,
216 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
217 curthread->td_locks++;
221 _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
224 if (SCHEDULER_STOPPED())
226 KASSERT(m->mtx_lock != MTX_DESTROYED,
227 ("mtx_unlock() of destroyed mutex @ %s:%d", file, line));
228 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
229 ("mtx_unlock() of spin mutex %s @ %s:%d", m->lock_object.lo_name,
231 curthread->td_locks--;
232 WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
233 LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file,
235 mtx_assert(m, MA_OWNED);
237 if (m->mtx_recurse == 0)
238 LOCKSTAT_PROFILE_RELEASE_LOCK(LS_MTX_UNLOCK_RELEASE, m);
239 __mtx_unlock(m, curthread, opts, file, line);
243 _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file, int line)
246 if (SCHEDULER_STOPPED())
248 KASSERT(m->mtx_lock != MTX_DESTROYED,
249 ("mtx_lock_spin() of destroyed mutex @ %s:%d", file, line));
250 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
251 ("mtx_lock_spin() of sleep mutex %s @ %s:%d",
252 m->lock_object.lo_name, file, line));
254 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0,
255 ("mtx_lock_spin: recursed on non-recursive mutex %s @ %s:%d\n",
256 m->lock_object.lo_name, file, line));
257 WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE,
259 __mtx_lock_spin(m, curthread, opts, file, line);
260 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file,
262 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
266 _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file, int line)
269 if (SCHEDULER_STOPPED())
271 KASSERT(m->mtx_lock != MTX_DESTROYED,
272 ("mtx_unlock_spin() of destroyed mutex @ %s:%d", file, line));
273 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
274 ("mtx_unlock_spin() of sleep mutex %s @ %s:%d",
275 m->lock_object.lo_name, file, line));
276 WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
277 LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file,
279 mtx_assert(m, MA_OWNED);
281 __mtx_unlock_spin(m);
285 * The important part of mtx_trylock{,_flags}()
286 * Tries to acquire lock `m.' If this function is called on a mutex that
287 * is already owned, it will recursively acquire the lock.
290 _mtx_trylock(struct mtx *m, int opts, const char *file, int line)
292 #ifdef LOCK_PROFILING
293 uint64_t waittime = 0;
298 if (SCHEDULER_STOPPED())
301 KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(curthread),
302 ("mtx_trylock() by idle thread %p on sleep mutex %s @ %s:%d",
303 curthread, m->lock_object.lo_name, file, line));
304 KASSERT(m->mtx_lock != MTX_DESTROYED,
305 ("mtx_trylock() of destroyed mutex @ %s:%d", file, line));
306 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
307 ("mtx_trylock() of spin mutex %s @ %s:%d", m->lock_object.lo_name,
310 if (mtx_owned(m) && (m->lock_object.lo_flags & LO_RECURSABLE) != 0) {
312 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
315 rval = _mtx_obtain_lock(m, (uintptr_t)curthread);
317 LOCK_LOG_TRY("LOCK", &m->lock_object, opts, rval, file, line);
319 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK,
321 curthread->td_locks++;
322 if (m->mtx_recurse == 0)
323 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_LOCK_ACQUIRE,
324 m, contested, waittime, file, line);
332 * _mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock.
334 * We call this if the lock is either contested (i.e. we need to go to
335 * sleep waiting for it), or if we need to recurse on it.
338 _mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts, const char *file,
341 struct turnstile *ts;
343 #ifdef ADAPTIVE_MUTEXES
344 volatile struct thread *owner;
349 #ifdef LOCK_PROFILING
351 uint64_t waittime = 0;
354 uint64_t spin_cnt = 0;
355 uint64_t sleep_cnt = 0;
356 int64_t sleep_time = 0;
359 if (SCHEDULER_STOPPED())
363 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0,
364 ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n",
365 m->lock_object.lo_name, file, line));
367 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
368 if (LOCK_LOG_TEST(&m->lock_object, opts))
369 CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m);
374 PMC_SOFT_CALL( , , lock, failed);
376 lock_profile_obtain_lock_failed(&m->lock_object,
377 &contested, &waittime);
378 if (LOCK_LOG_TEST(&m->lock_object, opts))
380 "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d",
381 m->lock_object.lo_name, (void *)m->mtx_lock, file, line);
383 while (!_mtx_obtain_lock(m, tid)) {
387 #ifdef ADAPTIVE_MUTEXES
389 * If the owner is running on another CPU, spin until the
390 * owner stops running or the state of the lock changes.
393 if (v != MTX_UNOWNED) {
394 owner = (struct thread *)(v & ~MTX_FLAGMASK);
395 if (TD_IS_RUNNING(owner)) {
396 if (LOCK_LOG_TEST(&m->lock_object, 0))
398 "%s: spinning on %p held by %p",
400 while (mtx_owner(m) == owner &&
401 TD_IS_RUNNING(owner)) {
412 ts = turnstile_trywait(&m->lock_object);
416 * Check if the lock has been released while spinning for
417 * the turnstile chain lock.
419 if (v == MTX_UNOWNED) {
420 turnstile_cancel(ts);
424 #ifdef ADAPTIVE_MUTEXES
426 * The current lock owner might have started executing
427 * on another CPU (or the lock could have changed
428 * owners) while we were waiting on the turnstile
429 * chain lock. If so, drop the turnstile lock and try
432 owner = (struct thread *)(v & ~MTX_FLAGMASK);
433 if (TD_IS_RUNNING(owner)) {
434 turnstile_cancel(ts);
440 * If the mutex isn't already contested and a failure occurs
441 * setting the contested bit, the mutex was either released
442 * or the state of the MTX_RECURSED bit changed.
444 if ((v & MTX_CONTESTED) == 0 &&
445 !atomic_cmpset_ptr(&m->mtx_lock, v, v | MTX_CONTESTED)) {
446 turnstile_cancel(ts);
451 * We definitely must sleep for this lock.
453 mtx_assert(m, MA_NOTOWNED);
458 "contention: %p at %s:%d wants %s, taken by %s:%d",
459 (void *)tid, file, line, m->lock_object.lo_name,
460 WITNESS_FILE(&m->lock_object),
461 WITNESS_LINE(&m->lock_object));
467 * Block on the turnstile.
470 sleep_time -= lockstat_nsecs();
472 turnstile_wait(ts, mtx_owner(m), TS_EXCLUSIVE_QUEUE);
474 sleep_time += lockstat_nsecs();
481 "contention end: %s acquired by %p at %s:%d",
482 m->lock_object.lo_name, (void *)tid, file, line);
485 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_LOCK_ACQUIRE, m, contested,
486 waittime, file, line);
489 LOCKSTAT_RECORD1(LS_MTX_LOCK_BLOCK, m, sleep_time);
492 * Only record the loops spinning and not sleeping.
494 if (spin_cnt > sleep_cnt)
495 LOCKSTAT_RECORD1(LS_MTX_LOCK_SPIN, m, (spin_cnt - sleep_cnt));
500 _mtx_lock_spin_failed(struct mtx *m)
506 /* If the mutex is unlocked, try again. */
510 printf( "spin lock %p (%s) held by %p (tid %d) too long\n",
511 m, m->lock_object.lo_name, td, td->td_tid);
513 witness_display_spinlock(&m->lock_object, td, printf);
515 panic("spin lock held too long");
520 * _mtx_lock_spin: the tougher part of acquiring an MTX_SPIN lock.
522 * This is only called if we need to actually spin for the lock. Recursion
526 _mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts, const char *file,
530 #ifdef LOCK_PROFILING
532 uint64_t waittime = 0;
535 if (SCHEDULER_STOPPED())
538 if (LOCK_LOG_TEST(&m->lock_object, opts))
539 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m);
542 PMC_SOFT_CALL( , , lock, failed);
544 lock_profile_obtain_lock_failed(&m->lock_object, &contested, &waittime);
545 while (!_mtx_obtain_lock(m, tid)) {
547 /* Give interrupts a chance while we spin. */
549 while (m->mtx_lock != MTX_UNOWNED) {
550 if (i++ < 10000000) {
554 if (i < 60000000 || kdb_active || panicstr != NULL)
557 _mtx_lock_spin_failed(m);
563 if (LOCK_LOG_TEST(&m->lock_object, opts))
564 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m);
566 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE, m,
567 contested, waittime, (file), (line));
568 LOCKSTAT_RECORD1(LS_MTX_SPIN_LOCK_SPIN, m, i);
573 _thread_lock_flags(struct thread *td, int opts, const char *file, int line)
578 #ifdef LOCK_PROFILING
580 uint64_t waittime = 0;
583 uint64_t spin_cnt = 0;
587 tid = (uintptr_t)curthread;
589 if (SCHEDULER_STOPPED())
596 KASSERT(m->mtx_lock != MTX_DESTROYED,
597 ("thread_lock() of destroyed mutex @ %s:%d", file, line));
598 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
599 ("thread_lock() of sleep mutex %s @ %s:%d",
600 m->lock_object.lo_name, file, line));
602 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0,
603 ("thread_lock: recursed on non-recursive mutex %s @ %s:%d\n",
604 m->lock_object.lo_name, file, line));
605 WITNESS_CHECKORDER(&m->lock_object,
606 opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL);
607 while (!_mtx_obtain_lock(m, tid)) {
611 if (m->mtx_lock == tid) {
616 PMC_SOFT_CALL( , , lock, failed);
618 lock_profile_obtain_lock_failed(&m->lock_object,
619 &contested, &waittime);
620 /* Give interrupts a chance while we spin. */
622 while (m->mtx_lock != MTX_UNOWNED) {
625 else if (i < 60000000 ||
626 kdb_active || panicstr != NULL)
629 _mtx_lock_spin_failed(m);
631 if (m != td->td_lock)
636 if (m == td->td_lock)
638 __mtx_unlock_spin(m); /* does spinlock_exit() */
643 if (m->mtx_recurse == 0)
644 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE,
645 m, contested, waittime, (file), (line));
646 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file,
648 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
649 LOCKSTAT_RECORD1(LS_THREAD_LOCK_SPIN, m, spin_cnt);
653 thread_lock_block(struct thread *td)
657 THREAD_LOCK_ASSERT(td, MA_OWNED);
659 td->td_lock = &blocked_lock;
660 mtx_unlock_spin(lock);
666 thread_lock_unblock(struct thread *td, struct mtx *new)
668 mtx_assert(new, MA_OWNED);
669 MPASS(td->td_lock == &blocked_lock);
670 atomic_store_rel_ptr((volatile void *)&td->td_lock, (uintptr_t)new);
674 thread_lock_set(struct thread *td, struct mtx *new)
678 mtx_assert(new, MA_OWNED);
679 THREAD_LOCK_ASSERT(td, MA_OWNED);
682 mtx_unlock_spin(lock);
686 * _mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock.
688 * We are only called here if the lock is recursed or contested (i.e. we
689 * need to wake up a blocked thread).
692 _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line)
694 struct turnstile *ts;
696 if (SCHEDULER_STOPPED())
699 if (mtx_recursed(m)) {
700 if (--(m->mtx_recurse) == 0)
701 atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED);
702 if (LOCK_LOG_TEST(&m->lock_object, opts))
703 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m);
708 * We have to lock the chain before the turnstile so this turnstile
709 * can be removed from the hash list if it is empty.
711 turnstile_chain_lock(&m->lock_object);
712 ts = turnstile_lookup(&m->lock_object);
713 if (LOCK_LOG_TEST(&m->lock_object, opts))
714 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m);
716 turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE);
717 _mtx_release_lock_quick(m);
720 * This turnstile is now no longer associated with the mutex. We can
721 * unlock the chain lock so a new turnstile may take it's place.
723 turnstile_unpend(ts, TS_EXCLUSIVE_LOCK);
724 turnstile_chain_unlock(&m->lock_object);
728 * All the unlocking of MTX_SPIN locks is done inline.
729 * See the __mtx_unlock_spin() macro for the details.
733 * The backing function for the INVARIANTS-enabled mtx_assert()
735 #ifdef INVARIANT_SUPPORT
737 _mtx_assert(struct mtx *m, int what, const char *file, int line)
740 if (panicstr != NULL || dumping)
744 case MA_OWNED | MA_RECURSED:
745 case MA_OWNED | MA_NOTRECURSED:
747 panic("mutex %s not owned at %s:%d",
748 m->lock_object.lo_name, file, line);
749 if (mtx_recursed(m)) {
750 if ((what & MA_NOTRECURSED) != 0)
751 panic("mutex %s recursed at %s:%d",
752 m->lock_object.lo_name, file, line);
753 } else if ((what & MA_RECURSED) != 0) {
754 panic("mutex %s unrecursed at %s:%d",
755 m->lock_object.lo_name, file, line);
760 panic("mutex %s owned at %s:%d",
761 m->lock_object.lo_name, file, line);
764 panic("unknown mtx_assert at %s:%d", file, line);
770 * The MUTEX_DEBUG-enabled mtx_validate()
772 * Most of these checks have been moved off into the LO_INITIALIZED flag
773 * maintained by the witness code.
777 void mtx_validate(struct mtx *);
780 mtx_validate(struct mtx *m)
784 * XXX: When kernacc() does not require Giant we can reenable this check
788 * Can't call kernacc() from early init386(), especially when
789 * initializing Giant mutex, because some stuff in kernacc()
790 * requires Giant itself.
793 if (!kernacc((caddr_t)m, sizeof(m),
794 VM_PROT_READ | VM_PROT_WRITE))
795 panic("Can't read and write to mutex %p", m);
801 * General init routine used by the MTX_SYSINIT() macro.
804 mtx_sysinit(void *arg)
806 struct mtx_args *margs = arg;
808 mtx_init(margs->ma_mtx, margs->ma_desc, NULL, margs->ma_opts);
812 * Mutex initialization routine; initialize lock `m' of type contained in
813 * `opts' with options contained in `opts' and name `name.' The optional
814 * lock type `type' is used as a general lock category name for use with
818 mtx_init(struct mtx *m, const char *name, const char *type, int opts)
820 struct lock_class *class;
823 MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE |
824 MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE)) == 0);
825 ASSERT_ATOMIC_LOAD_PTR(m->mtx_lock,
826 ("%s: mtx_lock not aligned for %s: %p", __func__, name,
830 /* Diagnostic and error correction */
834 /* Determine lock class and lock flags. */
836 class = &lock_class_mtx_spin;
838 class = &lock_class_mtx_sleep;
840 if (opts & MTX_QUIET)
842 if (opts & MTX_RECURSE)
843 flags |= LO_RECURSABLE;
844 if ((opts & MTX_NOWITNESS) == 0)
846 if (opts & MTX_DUPOK)
848 if (opts & MTX_NOPROFILE)
849 flags |= LO_NOPROFILE;
851 /* Initialize mutex. */
852 m->mtx_lock = MTX_UNOWNED;
855 lock_init(&m->lock_object, class, name, type, flags);
859 * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be
860 * passed in as a flag here because if the corresponding mtx_init() was
861 * called with MTX_QUIET set, then it will already be set in the mutex's
865 mtx_destroy(struct mtx *m)
869 MPASS(mtx_unowned(m));
871 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0);
873 /* Perform the non-mtx related part of mtx_unlock_spin(). */
874 if (LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin)
877 curthread->td_locks--;
879 lock_profile_release_lock(&m->lock_object);
880 /* Tell witness this isn't locked to make it happy. */
881 WITNESS_UNLOCK(&m->lock_object, LOP_EXCLUSIVE, __FILE__,
885 m->mtx_lock = MTX_DESTROYED;
886 lock_destroy(&m->lock_object);
890 * Intialize the mutex code and system mutexes. This is called from the MD
891 * startup code prior to mi_startup(). The per-CPU data space needs to be
892 * setup before this is called.
898 /* Setup turnstiles so that sleep mutexes work. */
902 * Initialize mutexes.
904 mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE);
905 mtx_init(&blocked_lock, "blocked lock", NULL, MTX_SPIN);
906 blocked_lock.mtx_lock = 0xdeadc0de; /* Always blocked. */
907 mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK);
908 mtx_init(&proc0.p_slock, "process slock", NULL, MTX_SPIN | MTX_RECURSE);
909 mtx_init(&devmtx, "cdev", NULL, MTX_DEF);
915 db_show_mtx(struct lock_object *lock)
920 m = (struct mtx *)lock;
922 db_printf(" flags: {");
923 if (LOCK_CLASS(lock) == &lock_class_mtx_spin)
927 if (m->lock_object.lo_flags & LO_RECURSABLE)
928 db_printf(", RECURSE");
929 if (m->lock_object.lo_flags & LO_DUPOK)
930 db_printf(", DUPOK");
932 db_printf(" state: {");
934 db_printf("UNOWNED");
935 else if (mtx_destroyed(m))
936 db_printf("DESTROYED");
939 if (m->mtx_lock & MTX_CONTESTED)
940 db_printf(", CONTESTED");
941 if (m->mtx_lock & MTX_RECURSED)
942 db_printf(", RECURSED");
945 if (!mtx_unowned(m) && !mtx_destroyed(m)) {
947 db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td,
948 td->td_tid, td->td_proc->p_pid, td->td_name);
950 db_printf(" recursed: %d\n", m->mtx_recurse);