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_sched.h"
45 #include <sys/param.h>
46 #include <sys/systm.h>
50 #include <sys/kernel.h>
53 #include <sys/malloc.h>
54 #include <sys/mutex.h>
56 #include <sys/resourcevar.h>
57 #include <sys/sched.h>
59 #include <sys/sysctl.h>
60 #include <sys/turnstile.h>
61 #include <sys/vmmeter.h>
62 #include <sys/lock_profile.h>
64 #include <machine/atomic.h>
65 #include <machine/bus.h>
66 #include <machine/cpu.h>
70 #include <fs/devfs/devfs_int.h>
73 #include <vm/vm_extern.h>
75 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES)
76 #define ADAPTIVE_MUTEXES
80 #include <sys/pmckern.h>
81 PMC_SOFT_DEFINE( , , lock, failed);
85 * Return the mutex address when the lock cookie address is provided.
86 * This functionality assumes that struct mtx* have a member named mtx_lock.
88 #define mtxlock2mtx(c) (__containerof(c, struct mtx, mtx_lock))
91 * Internal utility macros.
93 #define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED)
95 #define mtx_destroyed(m) ((m)->mtx_lock == MTX_DESTROYED)
97 #define mtx_owner(m) ((struct thread *)((m)->mtx_lock & ~MTX_FLAGMASK))
99 static void assert_mtx(const struct lock_object *lock, int what);
101 static void db_show_mtx(const struct lock_object *lock);
103 static void lock_mtx(struct lock_object *lock, uintptr_t how);
104 static void lock_spin(struct lock_object *lock, uintptr_t how);
106 static int owner_mtx(const struct lock_object *lock,
107 struct thread **owner);
109 static uintptr_t unlock_mtx(struct lock_object *lock);
110 static uintptr_t unlock_spin(struct lock_object *lock);
113 * Lock classes for sleep and spin mutexes.
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,
120 .lc_ddb_show = db_show_mtx,
123 .lc_unlock = unlock_mtx,
125 .lc_owner = owner_mtx,
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,
133 .lc_ddb_show = db_show_mtx,
135 .lc_lock = lock_spin,
136 .lc_unlock = unlock_spin,
138 .lc_owner = owner_mtx,
143 * System-wide mutexes
145 struct mtx blocked_lock;
149 assert_mtx(const struct lock_object *lock, int what)
152 mtx_assert((const struct mtx *)lock, what);
156 lock_mtx(struct lock_object *lock, uintptr_t how)
159 mtx_lock((struct mtx *)lock);
163 lock_spin(struct lock_object *lock, uintptr_t how)
166 panic("spin locks can only use msleep_spin");
170 unlock_mtx(struct lock_object *lock)
174 m = (struct mtx *)lock;
175 mtx_assert(m, MA_OWNED | MA_NOTRECURSED);
181 unlock_spin(struct lock_object *lock)
184 panic("spin locks can only use msleep_spin");
189 owner_mtx(const struct lock_object *lock, struct thread **owner)
191 const struct mtx *m = (const struct mtx *)lock;
193 *owner = mtx_owner(m);
194 return (mtx_unowned(m) == 0);
199 * Function versions of the inlined __mtx_* macros. These are used by
200 * modules and can also be called from assembly language if needed.
203 __mtx_lock_flags(volatile uintptr_t *c, int opts, const char *file, int line)
207 if (SCHEDULER_STOPPED())
212 KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(curthread),
213 ("mtx_lock() by idle thread %p on sleep mutex %s @ %s:%d",
214 curthread, m->lock_object.lo_name, file, line));
215 KASSERT(m->mtx_lock != MTX_DESTROYED,
216 ("mtx_lock() of destroyed mutex @ %s:%d", file, line));
217 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
218 ("mtx_lock() of spin mutex %s @ %s:%d", m->lock_object.lo_name,
220 WITNESS_CHECKORDER(&m->lock_object, (opts & ~MTX_RECURSE) |
221 LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL);
223 __mtx_lock(m, curthread, opts, file, line);
224 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file,
226 WITNESS_LOCK(&m->lock_object, (opts & ~MTX_RECURSE) | LOP_EXCLUSIVE,
228 curthread->td_locks++;
232 __mtx_unlock_flags(volatile uintptr_t *c, int opts, const char *file, int line)
236 if (SCHEDULER_STOPPED())
241 KASSERT(m->mtx_lock != MTX_DESTROYED,
242 ("mtx_unlock() of destroyed mutex @ %s:%d", file, line));
243 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
244 ("mtx_unlock() of spin mutex %s @ %s:%d", m->lock_object.lo_name,
246 WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
247 LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file,
249 mtx_assert(m, MA_OWNED);
251 __mtx_unlock(m, curthread, opts, file, line);
252 curthread->td_locks--;
256 __mtx_lock_spin_flags(volatile uintptr_t *c, int opts, const char *file,
261 if (SCHEDULER_STOPPED())
266 KASSERT(m->mtx_lock != MTX_DESTROYED,
267 ("mtx_lock_spin() of destroyed mutex @ %s:%d", file, line));
268 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
269 ("mtx_lock_spin() of sleep mutex %s @ %s:%d",
270 m->lock_object.lo_name, file, line));
272 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0 ||
273 (opts & MTX_RECURSE) != 0,
274 ("mtx_lock_spin: recursed on non-recursive mutex %s @ %s:%d\n",
275 m->lock_object.lo_name, file, line));
276 opts &= ~MTX_RECURSE;
277 WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE,
279 __mtx_lock_spin(m, curthread, opts, file, line);
280 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file,
282 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
286 __mtx_unlock_spin_flags(volatile uintptr_t *c, int opts, const char *file,
291 if (SCHEDULER_STOPPED())
296 KASSERT(m->mtx_lock != MTX_DESTROYED,
297 ("mtx_unlock_spin() of destroyed mutex @ %s:%d", file, line));
298 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
299 ("mtx_unlock_spin() of sleep mutex %s @ %s:%d",
300 m->lock_object.lo_name, file, line));
301 WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
302 LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file,
304 mtx_assert(m, MA_OWNED);
306 __mtx_unlock_spin(m);
310 * The important part of mtx_trylock{,_flags}()
311 * Tries to acquire lock `m.' If this function is called on a mutex that
312 * is already owned, it will recursively acquire the lock.
315 _mtx_trylock_flags_(volatile uintptr_t *c, int opts, const char *file, int line)
318 #ifdef LOCK_PROFILING
319 uint64_t waittime = 0;
324 if (SCHEDULER_STOPPED())
329 KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(curthread),
330 ("mtx_trylock() by idle thread %p on sleep mutex %s @ %s:%d",
331 curthread, m->lock_object.lo_name, file, line));
332 KASSERT(m->mtx_lock != MTX_DESTROYED,
333 ("mtx_trylock() of destroyed mutex @ %s:%d", file, line));
334 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
335 ("mtx_trylock() of spin mutex %s @ %s:%d", m->lock_object.lo_name,
338 if (mtx_owned(m) && ((m->lock_object.lo_flags & LO_RECURSABLE) != 0 ||
339 (opts & MTX_RECURSE) != 0)) {
341 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
344 rval = _mtx_obtain_lock(m, (uintptr_t)curthread);
345 opts &= ~MTX_RECURSE;
347 LOCK_LOG_TRY("LOCK", &m->lock_object, opts, rval, file, line);
349 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK,
351 curthread->td_locks++;
352 if (m->mtx_recurse == 0)
353 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_LOCK_ACQUIRE,
354 m, contested, waittime, file, line);
362 * __mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock.
364 * We call this if the lock is either contested (i.e. we need to go to
365 * sleep waiting for it), or if we need to recurse on it.
368 __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t tid, int opts,
369 const char *file, int line)
372 struct turnstile *ts;
374 #ifdef ADAPTIVE_MUTEXES
375 volatile struct thread *owner;
380 #ifdef LOCK_PROFILING
382 uint64_t waittime = 0;
385 uint64_t spin_cnt = 0;
386 uint64_t sleep_cnt = 0;
387 int64_t sleep_time = 0;
390 if (SCHEDULER_STOPPED())
396 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0 ||
397 (opts & MTX_RECURSE) != 0,
398 ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n",
399 m->lock_object.lo_name, file, line));
400 opts &= ~MTX_RECURSE;
402 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
403 if (LOCK_LOG_TEST(&m->lock_object, opts))
404 CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m);
407 opts &= ~MTX_RECURSE;
410 PMC_SOFT_CALL( , , lock, failed);
412 lock_profile_obtain_lock_failed(&m->lock_object,
413 &contested, &waittime);
414 if (LOCK_LOG_TEST(&m->lock_object, opts))
416 "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d",
417 m->lock_object.lo_name, (void *)m->mtx_lock, file, line);
419 while (!_mtx_obtain_lock(m, tid)) {
423 #ifdef ADAPTIVE_MUTEXES
425 * If the owner is running on another CPU, spin until the
426 * owner stops running or the state of the lock changes.
429 if (v != MTX_UNOWNED) {
430 owner = (struct thread *)(v & ~MTX_FLAGMASK);
431 if (TD_IS_RUNNING(owner)) {
432 if (LOCK_LOG_TEST(&m->lock_object, 0))
434 "%s: spinning on %p held by %p",
436 while (mtx_owner(m) == owner &&
437 TD_IS_RUNNING(owner)) {
448 ts = turnstile_trywait(&m->lock_object);
452 * Check if the lock has been released while spinning for
453 * the turnstile chain lock.
455 if (v == MTX_UNOWNED) {
456 turnstile_cancel(ts);
460 #ifdef ADAPTIVE_MUTEXES
462 * The current lock owner might have started executing
463 * on another CPU (or the lock could have changed
464 * owners) while we were waiting on the turnstile
465 * chain lock. If so, drop the turnstile lock and try
468 owner = (struct thread *)(v & ~MTX_FLAGMASK);
469 if (TD_IS_RUNNING(owner)) {
470 turnstile_cancel(ts);
476 * If the mutex isn't already contested and a failure occurs
477 * setting the contested bit, the mutex was either released
478 * or the state of the MTX_RECURSED bit changed.
480 if ((v & MTX_CONTESTED) == 0 &&
481 !atomic_cmpset_ptr(&m->mtx_lock, v, v | MTX_CONTESTED)) {
482 turnstile_cancel(ts);
487 * We definitely must sleep for this lock.
489 mtx_assert(m, MA_NOTOWNED);
494 "contention: %p at %s:%d wants %s, taken by %s:%d",
495 (void *)tid, file, line, m->lock_object.lo_name,
496 WITNESS_FILE(&m->lock_object),
497 WITNESS_LINE(&m->lock_object));
503 * Block on the turnstile.
506 sleep_time -= lockstat_nsecs();
508 turnstile_wait(ts, mtx_owner(m), TS_EXCLUSIVE_QUEUE);
510 sleep_time += lockstat_nsecs();
517 "contention end: %s acquired by %p at %s:%d",
518 m->lock_object.lo_name, (void *)tid, file, line);
521 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_LOCK_ACQUIRE, m, contested,
522 waittime, file, line);
525 LOCKSTAT_RECORD1(LS_MTX_LOCK_BLOCK, m, sleep_time);
528 * Only record the loops spinning and not sleeping.
530 if (spin_cnt > sleep_cnt)
531 LOCKSTAT_RECORD1(LS_MTX_LOCK_SPIN, m, (spin_cnt - sleep_cnt));
536 _mtx_lock_spin_failed(struct mtx *m)
542 /* If the mutex is unlocked, try again. */
546 printf( "spin lock %p (%s) held by %p (tid %d) too long\n",
547 m, m->lock_object.lo_name, td, td->td_tid);
549 witness_display_spinlock(&m->lock_object, td, printf);
551 panic("spin lock held too long");
556 * _mtx_lock_spin_cookie: the tougher part of acquiring an MTX_SPIN lock.
558 * This is only called if we need to actually spin for the lock. Recursion
562 _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t tid, int opts,
563 const char *file, int line)
567 #ifdef LOCK_PROFILING
569 uint64_t waittime = 0;
572 if (SCHEDULER_STOPPED())
577 if (LOCK_LOG_TEST(&m->lock_object, opts))
578 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m);
581 PMC_SOFT_CALL( , , lock, failed);
583 lock_profile_obtain_lock_failed(&m->lock_object, &contested, &waittime);
584 while (!_mtx_obtain_lock(m, tid)) {
586 /* Give interrupts a chance while we spin. */
588 while (m->mtx_lock != MTX_UNOWNED) {
589 if (i++ < 10000000) {
593 if (i < 60000000 || kdb_active || panicstr != NULL)
596 _mtx_lock_spin_failed(m);
602 if (LOCK_LOG_TEST(&m->lock_object, opts))
603 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m);
605 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE, m,
606 contested, waittime, (file), (line));
607 LOCKSTAT_RECORD1(LS_MTX_SPIN_LOCK_SPIN, m, i);
612 thread_lock_flags_(struct thread *td, int opts, const char *file, int line)
617 #ifdef LOCK_PROFILING
619 uint64_t waittime = 0;
622 uint64_t spin_cnt = 0;
626 tid = (uintptr_t)curthread;
628 if (SCHEDULER_STOPPED())
635 KASSERT(m->mtx_lock != MTX_DESTROYED,
636 ("thread_lock() of destroyed mutex @ %s:%d", file, line));
637 KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
638 ("thread_lock() of sleep mutex %s @ %s:%d",
639 m->lock_object.lo_name, file, line));
641 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0,
642 ("thread_lock: recursed on non-recursive mutex %s @ %s:%d\n",
643 m->lock_object.lo_name, file, line));
644 WITNESS_CHECKORDER(&m->lock_object,
645 opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL);
646 while (!_mtx_obtain_lock(m, tid)) {
650 if (m->mtx_lock == tid) {
655 PMC_SOFT_CALL( , , lock, failed);
657 lock_profile_obtain_lock_failed(&m->lock_object,
658 &contested, &waittime);
659 /* Give interrupts a chance while we spin. */
661 while (m->mtx_lock != MTX_UNOWNED) {
664 else if (i < 60000000 ||
665 kdb_active || panicstr != NULL)
668 _mtx_lock_spin_failed(m);
670 if (m != td->td_lock)
675 if (m == td->td_lock)
677 __mtx_unlock_spin(m); /* does spinlock_exit() */
682 if (m->mtx_recurse == 0)
683 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE,
684 m, contested, waittime, (file), (line));
685 LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file,
687 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
688 LOCKSTAT_RECORD1(LS_THREAD_LOCK_SPIN, m, spin_cnt);
692 thread_lock_block(struct thread *td)
696 THREAD_LOCK_ASSERT(td, MA_OWNED);
698 td->td_lock = &blocked_lock;
699 mtx_unlock_spin(lock);
705 thread_lock_unblock(struct thread *td, struct mtx *new)
707 mtx_assert(new, MA_OWNED);
708 MPASS(td->td_lock == &blocked_lock);
709 atomic_store_rel_ptr((volatile void *)&td->td_lock, (uintptr_t)new);
713 thread_lock_set(struct thread *td, struct mtx *new)
717 mtx_assert(new, MA_OWNED);
718 THREAD_LOCK_ASSERT(td, MA_OWNED);
721 mtx_unlock_spin(lock);
725 * __mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock.
727 * We are only called here if the lock is recursed or contested (i.e. we
728 * need to wake up a blocked thread).
731 __mtx_unlock_sleep(volatile uintptr_t *c, int opts, const char *file, int line)
734 struct turnstile *ts;
736 if (SCHEDULER_STOPPED())
741 if (mtx_recursed(m)) {
742 if (--(m->mtx_recurse) == 0)
743 atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED);
744 if (LOCK_LOG_TEST(&m->lock_object, opts))
745 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m);
750 * We have to lock the chain before the turnstile so this turnstile
751 * can be removed from the hash list if it is empty.
753 turnstile_chain_lock(&m->lock_object);
754 ts = turnstile_lookup(&m->lock_object);
755 if (LOCK_LOG_TEST(&m->lock_object, opts))
756 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m);
758 turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE);
759 _mtx_release_lock_quick(m);
762 * This turnstile is now no longer associated with the mutex. We can
763 * unlock the chain lock so a new turnstile may take it's place.
765 turnstile_unpend(ts, TS_EXCLUSIVE_LOCK);
766 turnstile_chain_unlock(&m->lock_object);
770 * All the unlocking of MTX_SPIN locks is done inline.
771 * See the __mtx_unlock_spin() macro for the details.
775 * The backing function for the INVARIANTS-enabled mtx_assert()
777 #ifdef INVARIANT_SUPPORT
779 __mtx_assert(const volatile uintptr_t *c, int what, const char *file, int line)
783 if (panicstr != NULL || dumping)
790 case MA_OWNED | MA_RECURSED:
791 case MA_OWNED | MA_NOTRECURSED:
793 panic("mutex %s not owned at %s:%d",
794 m->lock_object.lo_name, file, line);
795 if (mtx_recursed(m)) {
796 if ((what & MA_NOTRECURSED) != 0)
797 panic("mutex %s recursed at %s:%d",
798 m->lock_object.lo_name, file, line);
799 } else if ((what & MA_RECURSED) != 0) {
800 panic("mutex %s unrecursed at %s:%d",
801 m->lock_object.lo_name, file, line);
806 panic("mutex %s owned at %s:%d",
807 m->lock_object.lo_name, file, line);
810 panic("unknown mtx_assert at %s:%d", file, line);
816 * The MUTEX_DEBUG-enabled mtx_validate()
818 * Most of these checks have been moved off into the LO_INITIALIZED flag
819 * maintained by the witness code.
823 void mtx_validate(struct mtx *);
826 mtx_validate(struct mtx *m)
830 * XXX: When kernacc() does not require Giant we can reenable this check
834 * Can't call kernacc() from early init386(), especially when
835 * initializing Giant mutex, because some stuff in kernacc()
836 * requires Giant itself.
839 if (!kernacc((caddr_t)m, sizeof(m),
840 VM_PROT_READ | VM_PROT_WRITE))
841 panic("Can't read and write to mutex %p", m);
847 * General init routine used by the MTX_SYSINIT() macro.
850 mtx_sysinit(void *arg)
852 struct mtx_args *margs = arg;
854 mtx_init((struct mtx *)margs->ma_mtx, margs->ma_desc, NULL,
859 * Mutex initialization routine; initialize lock `m' of type contained in
860 * `opts' with options contained in `opts' and name `name.' The optional
861 * lock type `type' is used as a general lock category name for use with
865 _mtx_init(volatile uintptr_t *c, const char *name, const char *type, int opts)
868 struct lock_class *class;
873 MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE |
874 MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE)) == 0);
875 ASSERT_ATOMIC_LOAD_PTR(m->mtx_lock,
876 ("%s: mtx_lock not aligned for %s: %p", __func__, name,
880 /* Diagnostic and error correction */
884 /* Determine lock class and lock flags. */
886 class = &lock_class_mtx_spin;
888 class = &lock_class_mtx_sleep;
890 if (opts & MTX_QUIET)
892 if (opts & MTX_RECURSE)
893 flags |= LO_RECURSABLE;
894 if ((opts & MTX_NOWITNESS) == 0)
896 if (opts & MTX_DUPOK)
898 if (opts & MTX_NOPROFILE)
899 flags |= LO_NOPROFILE;
901 /* Initialize mutex. */
902 lock_init(&m->lock_object, class, name, type, flags);
904 m->mtx_lock = MTX_UNOWNED;
909 * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be
910 * passed in as a flag here because if the corresponding mtx_init() was
911 * called with MTX_QUIET set, then it will already be set in the mutex's
915 _mtx_destroy(volatile uintptr_t *c)
922 MPASS(mtx_unowned(m));
924 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0);
926 /* Perform the non-mtx related part of mtx_unlock_spin(). */
927 if (LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin)
930 curthread->td_locks--;
932 lock_profile_release_lock(&m->lock_object);
933 /* Tell witness this isn't locked to make it happy. */
934 WITNESS_UNLOCK(&m->lock_object, LOP_EXCLUSIVE, __FILE__,
938 m->mtx_lock = MTX_DESTROYED;
939 lock_destroy(&m->lock_object);
943 * Intialize the mutex code and system mutexes. This is called from the MD
944 * startup code prior to mi_startup(). The per-CPU data space needs to be
945 * setup before this is called.
951 /* Setup turnstiles so that sleep mutexes work. */
955 * Initialize mutexes.
957 mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE);
958 mtx_init(&blocked_lock, "blocked lock", NULL, MTX_SPIN);
959 blocked_lock.mtx_lock = 0xdeadc0de; /* Always blocked. */
960 mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK);
961 mtx_init(&proc0.p_slock, "process slock", NULL, MTX_SPIN | MTX_RECURSE);
962 mtx_init(&devmtx, "cdev", NULL, MTX_DEF);
968 db_show_mtx(const struct lock_object *lock)
973 m = (const struct mtx *)lock;
975 db_printf(" flags: {");
976 if (LOCK_CLASS(lock) == &lock_class_mtx_spin)
980 if (m->lock_object.lo_flags & LO_RECURSABLE)
981 db_printf(", RECURSE");
982 if (m->lock_object.lo_flags & LO_DUPOK)
983 db_printf(", DUPOK");
985 db_printf(" state: {");
987 db_printf("UNOWNED");
988 else if (mtx_destroyed(m))
989 db_printf("DESTROYED");
992 if (m->mtx_lock & MTX_CONTESTED)
993 db_printf(", CONTESTED");
994 if (m->mtx_lock & MTX_RECURSED)
995 db_printf(", RECURSED");
998 if (!mtx_unowned(m) && !mtx_destroyed(m)) {
1000 db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td,
1001 td->td_tid, td->td_proc->p_pid, td->td_name);
1002 if (mtx_recursed(m))
1003 db_printf(" recursed: %d\n", m->mtx_recurse);