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_mprof.h"
42 #include "opt_mutex_wake_all.h"
43 #include "opt_sched.h"
45 #include <sys/param.h>
46 #include <sys/systm.h>
49 #include <sys/kernel.h>
52 #include <sys/malloc.h>
53 #include <sys/mutex.h>
55 #include <sys/resourcevar.h>
56 #include <sys/sched.h>
58 #include <sys/sysctl.h>
59 #include <sys/turnstile.h>
60 #include <sys/vmmeter.h>
62 #include <machine/atomic.h>
63 #include <machine/bus.h>
64 #include <machine/clock.h>
65 #include <machine/cpu.h>
70 #include <vm/vm_extern.h>
73 * Force MUTEX_WAKE_ALL for now.
74 * single thread wakeup needs fixes to avoid race conditions with
75 * priority inheritance.
77 #ifndef MUTEX_WAKE_ALL
78 #define MUTEX_WAKE_ALL
82 * Internal utility macros.
84 #define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED)
86 #define mtx_owner(m) (mtx_unowned((m)) ? NULL \
87 : (struct thread *)((m)->mtx_lock & MTX_FLAGMASK))
90 * Lock classes for sleep and spin mutexes.
92 struct lock_class lock_class_mtx_sleep = {
94 LC_SLEEPLOCK | LC_RECURSABLE
96 struct lock_class lock_class_mtx_spin = {
98 LC_SPINLOCK | LC_RECURSABLE
102 * System-wide mutexes
104 struct mtx sched_lock;
107 #ifdef MUTEX_PROFILING
108 SYSCTL_NODE(_debug, OID_AUTO, mutex, CTLFLAG_RD, NULL, "mutex debugging");
109 SYSCTL_NODE(_debug_mutex, OID_AUTO, prof, CTLFLAG_RD, NULL, "mutex profiling");
110 static int mutex_prof_enable = 0;
111 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, enable, CTLFLAG_RW,
112 &mutex_prof_enable, 0, "Enable tracing of mutex holdtime");
121 uintmax_t cnt_contest_holding;
122 uintmax_t cnt_contest_locking;
123 struct mutex_prof *next;
127 * mprof_buf is a static pool of profiling records to avoid possible
128 * reentrance of the memory allocation functions.
130 * Note: NUM_MPROF_BUFFERS must be smaller than MPROF_HASH_SIZE.
133 #define NUM_MPROF_BUFFERS MPROF_BUFFERS
135 #define NUM_MPROF_BUFFERS 1000
137 static struct mutex_prof mprof_buf[NUM_MPROF_BUFFERS];
138 static int first_free_mprof_buf;
139 #ifndef MPROF_HASH_SIZE
140 #define MPROF_HASH_SIZE 1009
142 #if NUM_MPROF_BUFFERS >= MPROF_HASH_SIZE
143 #error MPROF_BUFFERS must be larger than MPROF_HASH_SIZE
145 static struct mutex_prof *mprof_hash[MPROF_HASH_SIZE];
146 /* SWAG: sbuf size = avg stat. line size * number of locks */
147 #define MPROF_SBUF_SIZE 256 * 400
149 static int mutex_prof_acquisitions;
150 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, acquisitions, CTLFLAG_RD,
151 &mutex_prof_acquisitions, 0, "Number of mutex acquistions recorded");
152 static int mutex_prof_records;
153 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, records, CTLFLAG_RD,
154 &mutex_prof_records, 0, "Number of profiling records");
155 static int mutex_prof_maxrecords = NUM_MPROF_BUFFERS;
156 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, maxrecords, CTLFLAG_RD,
157 &mutex_prof_maxrecords, 0, "Maximum number of profiling records");
158 static int mutex_prof_rejected;
159 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, rejected, CTLFLAG_RD,
160 &mutex_prof_rejected, 0, "Number of rejected profiling records");
161 static int mutex_prof_hashsize = MPROF_HASH_SIZE;
162 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, hashsize, CTLFLAG_RD,
163 &mutex_prof_hashsize, 0, "Hash size");
164 static int mutex_prof_collisions = 0;
165 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, collisions, CTLFLAG_RD,
166 &mutex_prof_collisions, 0, "Number of hash collisions");
169 * mprof_mtx protects the profiling buffers and the hash.
171 static struct mtx mprof_mtx;
172 MTX_SYSINIT(mprof, &mprof_mtx, "mutex profiling lock", MTX_SPIN | MTX_QUIET);
180 return (tv.tv_sec * (u_int64_t)1000000000 + tv.tv_nsec);
184 dump_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
188 static int multiplier = 1;
190 if (first_free_mprof_buf == 0)
191 return (SYSCTL_OUT(req, "No locking recorded",
192 sizeof("No locking recorded")));
195 sb = sbuf_new(NULL, NULL, MPROF_SBUF_SIZE * multiplier, SBUF_FIXEDLEN);
196 sbuf_printf(sb, "\n%6s %12s %11s %5s %12s %12s %s\n",
197 "max", "total", "count", "avg", "cnt_hold", "cnt_lock", "name");
199 * XXX this spinlock seems to be by far the largest perpetrator
200 * of spinlock latency (1.6 msec on an Athlon1600 was recorded
201 * even before I pessimized it further by moving the average
204 mtx_lock_spin(&mprof_mtx);
205 for (i = 0; i < first_free_mprof_buf; ++i) {
206 sbuf_printf(sb, "%6ju %12ju %11ju %5ju %12ju %12ju %s:%d (%s)\n",
207 mprof_buf[i].cnt_max / 1000,
208 mprof_buf[i].cnt_tot / 1000,
209 mprof_buf[i].cnt_cur,
210 mprof_buf[i].cnt_cur == 0 ? (uintmax_t)0 :
211 mprof_buf[i].cnt_tot / (mprof_buf[i].cnt_cur * 1000),
212 mprof_buf[i].cnt_contest_holding,
213 mprof_buf[i].cnt_contest_locking,
214 mprof_buf[i].file, mprof_buf[i].line, mprof_buf[i].name);
215 if (sbuf_overflowed(sb)) {
216 mtx_unlock_spin(&mprof_mtx);
222 mtx_unlock_spin(&mprof_mtx);
224 error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
228 SYSCTL_PROC(_debug_mutex_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD,
229 NULL, 0, dump_mutex_prof_stats, "A", "Mutex profiling statistics");
232 reset_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
236 if (first_free_mprof_buf == 0)
240 error = sysctl_handle_int(oidp, &v, 0, req);
243 if (req->newptr == NULL)
248 mtx_lock_spin(&mprof_mtx);
249 bzero(mprof_buf, sizeof(*mprof_buf) * first_free_mprof_buf);
250 bzero(mprof_hash, sizeof(struct mtx *) * MPROF_HASH_SIZE);
251 first_free_mprof_buf = 0;
252 mtx_unlock_spin(&mprof_mtx);
255 SYSCTL_PROC(_debug_mutex_prof, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW,
256 NULL, 0, reset_mutex_prof_stats, "I", "Reset mutex profiling statistics");
260 * Function versions of the inlined __mtx_* macros. These are used by
261 * modules and can also be called from assembly language if needed.
264 _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line)
267 MPASS(curthread != NULL);
268 KASSERT(m->mtx_object.lo_class == &lock_class_mtx_sleep,
269 ("mtx_lock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name,
271 WITNESS_CHECKORDER(&m->mtx_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE,
273 _get_sleep_lock(m, curthread, opts, file, line);
274 LOCK_LOG_LOCK("LOCK", &m->mtx_object, opts, m->mtx_recurse, file,
276 WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line);
277 #ifdef MUTEX_PROFILING
278 /* don't reset the timer when/if recursing */
279 if (m->mtx_acqtime == 0) {
280 m->mtx_filename = file;
281 m->mtx_lineno = line;
282 m->mtx_acqtime = mutex_prof_enable ? nanoseconds() : 0;
283 ++mutex_prof_acquisitions;
289 _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
292 MPASS(curthread != NULL);
293 KASSERT(m->mtx_object.lo_class == &lock_class_mtx_sleep,
294 ("mtx_unlock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name,
296 WITNESS_UNLOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line);
297 LOCK_LOG_LOCK("UNLOCK", &m->mtx_object, opts, m->mtx_recurse, file,
299 mtx_assert(m, MA_OWNED);
300 #ifdef MUTEX_PROFILING
301 if (m->mtx_acqtime != 0) {
302 static const char *unknown = "(unknown)";
303 struct mutex_prof *mpp;
304 u_int64_t acqtime, now;
309 acqtime = m->mtx_acqtime;
313 for (p = m->mtx_filename;
314 p != NULL && strncmp(p, "../", 3) == 0; p += 3)
316 if (p == NULL || *p == '\0')
318 for (hash = m->mtx_lineno, q = p; *q != '\0'; ++q)
319 hash = (hash * 2 + *q) % MPROF_HASH_SIZE;
320 mtx_lock_spin(&mprof_mtx);
321 for (mpp = mprof_hash[hash]; mpp != NULL; mpp = mpp->next)
322 if (mpp->line == m->mtx_lineno &&
323 strcmp(mpp->file, p) == 0)
326 /* Just exit if we cannot get a trace buffer */
327 if (first_free_mprof_buf >= NUM_MPROF_BUFFERS) {
328 ++mutex_prof_rejected;
331 mpp = &mprof_buf[first_free_mprof_buf++];
332 mpp->name = mtx_name(m);
334 mpp->line = m->mtx_lineno;
335 mpp->next = mprof_hash[hash];
336 if (mprof_hash[hash] != NULL)
337 ++mutex_prof_collisions;
338 mprof_hash[hash] = mpp;
339 ++mutex_prof_records;
342 * Record if the mutex has been held longer now than ever
345 if (now - acqtime > mpp->cnt_max)
346 mpp->cnt_max = now - acqtime;
347 mpp->cnt_tot += now - acqtime;
350 * There's a small race, really we should cmpxchg
351 * 0 with the current value, but that would bill
352 * the contention to the wrong lock instance if
353 * it followed this also.
355 mpp->cnt_contest_holding += m->mtx_contest_holding;
356 m->mtx_contest_holding = 0;
357 mpp->cnt_contest_locking += m->mtx_contest_locking;
358 m->mtx_contest_locking = 0;
360 mtx_unlock_spin(&mprof_mtx);
364 _rel_sleep_lock(m, curthread, opts, file, line);
368 _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file, int line)
371 MPASS(curthread != NULL);
372 KASSERT(m->mtx_object.lo_class == &lock_class_mtx_spin,
373 ("mtx_lock_spin() of sleep mutex %s @ %s:%d",
374 m->mtx_object.lo_name, file, line));
375 WITNESS_CHECKORDER(&m->mtx_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE,
377 _get_spin_lock(m, curthread, opts, file, line);
378 LOCK_LOG_LOCK("LOCK", &m->mtx_object, opts, m->mtx_recurse, file,
380 WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line);
384 _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file, int line)
387 MPASS(curthread != NULL);
388 KASSERT(m->mtx_object.lo_class == &lock_class_mtx_spin,
389 ("mtx_unlock_spin() of sleep mutex %s @ %s:%d",
390 m->mtx_object.lo_name, file, line));
391 WITNESS_UNLOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line);
392 LOCK_LOG_LOCK("UNLOCK", &m->mtx_object, opts, m->mtx_recurse, file,
394 mtx_assert(m, MA_OWNED);
399 * The important part of mtx_trylock{,_flags}()
400 * Tries to acquire lock `m.' If this function is called on a mutex that
401 * is already owned, it will recursively acquire the lock.
404 _mtx_trylock(struct mtx *m, int opts, const char *file, int line)
408 MPASS(curthread != NULL);
410 if (mtx_owned(m) && (m->mtx_object.lo_flags & LO_RECURSABLE) != 0) {
412 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
415 rval = _obtain_lock(m, curthread);
417 LOCK_LOG_TRY("LOCK", &m->mtx_object, opts, rval, file, line);
419 WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK,
426 * _mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock.
428 * We call this if the lock is either contested (i.e. we need to go to
429 * sleep waiting for it), or if we need to recurse on it.
432 _mtx_lock_sleep(struct mtx *m, struct thread *td, int opts, const char *file,
435 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES)
436 struct thread *owner;
442 #ifdef MUTEX_PROFILING
447 KASSERT((m->mtx_object.lo_flags & LO_RECURSABLE) != 0,
448 ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n",
449 m->mtx_object.lo_name, file, line));
451 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
452 if (LOCK_LOG_TEST(&m->mtx_object, opts))
453 CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m);
457 if (LOCK_LOG_TEST(&m->mtx_object, opts))
459 "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d",
460 m->mtx_object.lo_name, (void *)m->mtx_lock, file, line);
462 #ifdef MUTEX_PROFILING
465 while (!_obtain_lock(m, td)) {
466 #ifdef MUTEX_PROFILING
468 atomic_add_int(&m->mtx_contest_holding, 1);
470 turnstile_lock(&m->mtx_object);
474 * Check if the lock has been released while spinning for
475 * the turnstile chain lock.
477 if (v == MTX_UNOWNED) {
478 turnstile_release(&m->mtx_object);
483 #ifdef MUTEX_WAKE_ALL
484 MPASS(v != MTX_CONTESTED);
487 * The mutex was marked contested on release. This means that
488 * there are other threads blocked on it. Grab ownership of
489 * it and propagate its priority to the current thread if
492 if (v == MTX_CONTESTED) {
493 m->mtx_lock = (uintptr_t)td | MTX_CONTESTED;
494 turnstile_claim(&m->mtx_object);
500 * If the mutex isn't already contested and a failure occurs
501 * setting the contested bit, the mutex was either released
502 * or the state of the MTX_RECURSED bit changed.
504 if ((v & MTX_CONTESTED) == 0 &&
505 !atomic_cmpset_ptr(&m->mtx_lock, (void *)v,
506 (void *)(v | MTX_CONTESTED))) {
507 turnstile_release(&m->mtx_object);
512 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES)
514 * If the current owner of the lock is executing on another
515 * CPU, spin instead of blocking.
517 owner = (struct thread *)(v & MTX_FLAGMASK);
518 #ifdef ADAPTIVE_GIANT
519 if (TD_IS_RUNNING(owner)) {
521 if (m != &Giant && TD_IS_RUNNING(owner)) {
523 turnstile_release(&m->mtx_object);
524 while (mtx_owner(m) == owner && TD_IS_RUNNING(owner)) {
529 #endif /* SMP && !NO_ADAPTIVE_MUTEXES */
532 * We definitely must sleep for this lock.
534 mtx_assert(m, MA_NOTOWNED);
539 "contention: %p at %s:%d wants %s, taken by %s:%d",
540 td, file, line, m->mtx_object.lo_name,
541 WITNESS_FILE(&m->mtx_object),
542 WITNESS_LINE(&m->mtx_object));
548 * Block on the turnstile.
550 turnstile_wait(&m->mtx_object, mtx_owner(m));
556 "contention end: %s acquired by %p at %s:%d",
557 m->mtx_object.lo_name, td, file, line);
560 #ifdef MUTEX_PROFILING
562 m->mtx_contest_locking++;
563 m->mtx_contest_holding = 0;
570 * _mtx_lock_spin: the tougher part of acquiring an MTX_SPIN lock.
572 * This is only called if we need to actually spin for the lock. Recursion
576 _mtx_lock_spin(struct mtx *m, struct thread *td, int opts, const char *file,
581 if (LOCK_LOG_TEST(&m->mtx_object, opts))
582 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m);
585 if (_obtain_lock(m, td))
588 /* Give interrupts a chance while we spin. */
590 while (m->mtx_lock != MTX_UNOWNED) {
591 if (i++ < 10000000) {
597 else if (!kdb_active) {
598 printf("spin lock %s held by %p for > 5 seconds\n",
599 m->mtx_object.lo_name, (void *)m->mtx_lock);
601 witness_display_spinlock(&m->mtx_object,
604 panic("spin lock held too long");
611 if (LOCK_LOG_TEST(&m->mtx_object, opts))
612 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m);
619 * _mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock.
621 * We are only called here if the lock is recursed or contested (i.e. we
622 * need to wake up a blocked thread).
625 _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line)
627 struct turnstile *ts;
629 struct thread *td, *td1;
632 if (mtx_recursed(m)) {
633 if (--(m->mtx_recurse) == 0)
634 atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED);
635 if (LOCK_LOG_TEST(&m->mtx_object, opts))
636 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m);
640 turnstile_lock(&m->mtx_object);
641 ts = turnstile_lookup(&m->mtx_object);
642 if (LOCK_LOG_TEST(&m->mtx_object, opts))
643 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m);
645 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES)
647 _release_lock_quick(m);
648 if (LOCK_LOG_TEST(&m->mtx_object, opts))
649 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p no sleepers", m);
650 turnstile_release(&m->mtx_object);
658 td1 = turnstile_head(ts);
660 #ifdef MUTEX_WAKE_ALL
661 turnstile_broadcast(ts);
662 _release_lock_quick(m);
664 if (turnstile_signal(ts)) {
665 _release_lock_quick(m);
666 if (LOCK_LOG_TEST(&m->mtx_object, opts))
667 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p not held", m);
669 m->mtx_lock = MTX_CONTESTED;
670 if (LOCK_LOG_TEST(&m->mtx_object, opts))
671 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p still contested",
675 turnstile_unpend(ts);
679 * XXX: This is just a hack until preemption is done. However,
680 * once preemption is done we need to either wrap the
681 * turnstile_signal() and release of the actual lock in an
682 * extra critical section or change the preemption code to
683 * always just set a flag and never do instant-preempts.
686 if (td->td_critnest > 0 || td1->td_priority >= td->td_priority)
688 mtx_lock_spin(&sched_lock);
689 if (!TD_IS_RUNNING(td1)) {
691 if (td->td_ithd != NULL) {
692 struct ithd *it = td->td_ithd;
694 if (it->it_interrupted) {
695 if (LOCK_LOG_TEST(&m->mtx_object, opts))
697 "_mtx_unlock_sleep: %p interrupted %p",
698 it, it->it_interrupted);
703 if (LOCK_LOG_TEST(&m->mtx_object, opts))
705 "_mtx_unlock_sleep: %p switching out lock=%p", m,
706 (void *)m->mtx_lock);
708 mi_switch(SW_INVOL, NULL);
709 if (LOCK_LOG_TEST(&m->mtx_object, opts))
710 CTR2(KTR_LOCK, "_mtx_unlock_sleep: %p resuming lock=%p",
711 m, (void *)m->mtx_lock);
713 mtx_unlock_spin(&sched_lock);
720 * All the unlocking of MTX_SPIN locks is done inline.
721 * See the _rel_spin_lock() macro for the details.
725 * The backing function for the INVARIANTS-enabled mtx_assert()
727 #ifdef INVARIANT_SUPPORT
729 _mtx_assert(struct mtx *m, int what, const char *file, int line)
732 if (panicstr != NULL)
736 case MA_OWNED | MA_RECURSED:
737 case MA_OWNED | MA_NOTRECURSED:
739 panic("mutex %s not owned at %s:%d",
740 m->mtx_object.lo_name, file, line);
741 if (mtx_recursed(m)) {
742 if ((what & MA_NOTRECURSED) != 0)
743 panic("mutex %s recursed at %s:%d",
744 m->mtx_object.lo_name, file, line);
745 } else if ((what & MA_RECURSED) != 0) {
746 panic("mutex %s unrecursed at %s:%d",
747 m->mtx_object.lo_name, file, line);
752 panic("mutex %s owned at %s:%d",
753 m->mtx_object.lo_name, file, line);
756 panic("unknown mtx_assert at %s:%d", file, line);
762 * The MUTEX_DEBUG-enabled mtx_validate()
764 * Most of these checks have been moved off into the LO_INITIALIZED flag
765 * maintained by the witness code.
769 void mtx_validate(struct mtx *);
772 mtx_validate(struct mtx *m)
776 * XXX: When kernacc() does not require Giant we can reenable this check
780 * XXX - When kernacc() is fixed on the alpha to handle K0_SEG memory properly
781 * we can re-enable the kernacc() checks.
785 * Can't call kernacc() from early init386(), especially when
786 * initializing Giant mutex, because some stuff in kernacc()
787 * requires Giant itself.
790 if (!kernacc((caddr_t)m, sizeof(m),
791 VM_PROT_READ | VM_PROT_WRITE))
792 panic("Can't read and write to mutex %p", m);
799 * General init routine used by the MTX_SYSINIT() macro.
802 mtx_sysinit(void *arg)
804 struct mtx_args *margs = arg;
806 mtx_init(margs->ma_mtx, margs->ma_desc, NULL, margs->ma_opts);
810 * Mutex initialization routine; initialize lock `m' of type contained in
811 * `opts' with options contained in `opts' and name `name.' The optional
812 * lock type `type' is used as a general lock category name for use with
816 mtx_init(struct mtx *m, const char *name, const char *type, int opts)
818 struct lock_object *lock;
820 MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE |
821 MTX_NOWITNESS | MTX_DUPOK)) == 0);
824 /* Diagnostic and error correction */
828 lock = &m->mtx_object;
829 KASSERT((lock->lo_flags & LO_INITIALIZED) == 0,
830 ("mutex \"%s\" %p already initialized", name, m));
831 bzero(m, sizeof(*m));
833 lock->lo_class = &lock_class_mtx_spin;
835 lock->lo_class = &lock_class_mtx_sleep;
836 lock->lo_name = name;
837 lock->lo_type = type != NULL ? type : name;
838 if (opts & MTX_QUIET)
839 lock->lo_flags = LO_QUIET;
840 if (opts & MTX_RECURSE)
841 lock->lo_flags |= LO_RECURSABLE;
842 if ((opts & MTX_NOWITNESS) == 0)
843 lock->lo_flags |= LO_WITNESS;
844 if (opts & MTX_DUPOK)
845 lock->lo_flags |= LO_DUPOK;
847 m->mtx_lock = MTX_UNOWNED;
849 LOCK_LOG_INIT(lock, opts);
855 * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be
856 * passed in as a flag here because if the corresponding mtx_init() was
857 * called with MTX_QUIET set, then it will already be set in the mutex's
861 mtx_destroy(struct mtx *m)
864 LOCK_LOG_DESTROY(&m->mtx_object, 0);
867 MPASS(mtx_unowned(m));
869 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0);
871 /* Tell witness this isn't locked to make it happy. */
872 WITNESS_UNLOCK(&m->mtx_object, LOP_EXCLUSIVE, __FILE__,
876 WITNESS_DESTROY(&m->mtx_object);
880 * Intialize the mutex code and system mutexes. This is called from the MD
881 * startup code prior to mi_startup(). The per-CPU data space needs to be
882 * setup before this is called.
888 /* Setup thread0 so that mutexes work. */
889 LIST_INIT(&thread0.td_contested);
891 /* Setup turnstiles so that sleep mutexes work. */
895 * Initialize mutexes.
897 mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE);
898 mtx_init(&sched_lock, "sched lock", NULL, MTX_SPIN | MTX_RECURSE);
899 mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK);