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>
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>
63 #include <machine/atomic.h>
64 #include <machine/bus.h>
65 #include <machine/clock.h>
66 #include <machine/cpu.h>
70 #include <fs/devfs/devfs_int.h>
73 #include <vm/vm_extern.h>
76 * Force MUTEX_WAKE_ALL for now.
77 * single thread wakeup needs fixes to avoid race conditions with
78 * priority inheritance.
80 #ifndef MUTEX_WAKE_ALL
81 #define MUTEX_WAKE_ALL
85 * Internal utility macros.
87 #define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED)
89 #define mtx_owner(m) (mtx_unowned((m)) ? NULL \
90 : (struct thread *)((m)->mtx_lock & MTX_FLAGMASK))
93 static void db_show_mtx(struct lock_object *lock);
97 * Lock classes for sleep and spin mutexes.
99 struct lock_class lock_class_mtx_sleep = {
101 LC_SLEEPLOCK | LC_RECURSABLE,
106 struct lock_class lock_class_mtx_spin = {
108 LC_SPINLOCK | LC_RECURSABLE,
115 * System-wide mutexes
117 struct mtx sched_lock;
120 #ifdef MUTEX_PROFILING
121 SYSCTL_NODE(_debug, OID_AUTO, mutex, CTLFLAG_RD, NULL, "mutex debugging");
122 SYSCTL_NODE(_debug_mutex, OID_AUTO, prof, CTLFLAG_RD, NULL, "mutex profiling");
123 static int mutex_prof_enable = 0;
124 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, enable, CTLFLAG_RW,
125 &mutex_prof_enable, 0, "Enable tracing of mutex holdtime");
134 uintmax_t cnt_contest_holding;
135 uintmax_t cnt_contest_locking;
136 struct mutex_prof *next;
140 * mprof_buf is a static pool of profiling records to avoid possible
141 * reentrance of the memory allocation functions.
143 * Note: NUM_MPROF_BUFFERS must be smaller than MPROF_HASH_SIZE.
146 #define NUM_MPROF_BUFFERS MPROF_BUFFERS
148 #define NUM_MPROF_BUFFERS 1000
150 static struct mutex_prof mprof_buf[NUM_MPROF_BUFFERS];
151 static int first_free_mprof_buf;
152 #ifndef MPROF_HASH_SIZE
153 #define MPROF_HASH_SIZE 1009
155 #if NUM_MPROF_BUFFERS >= MPROF_HASH_SIZE
156 #error MPROF_BUFFERS must be larger than MPROF_HASH_SIZE
158 static struct mutex_prof *mprof_hash[MPROF_HASH_SIZE];
159 /* SWAG: sbuf size = avg stat. line size * number of locks */
160 #define MPROF_SBUF_SIZE 256 * 400
162 static int mutex_prof_acquisitions;
163 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, acquisitions, CTLFLAG_RD,
164 &mutex_prof_acquisitions, 0, "Number of mutex acquistions recorded");
165 static int mutex_prof_records;
166 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, records, CTLFLAG_RD,
167 &mutex_prof_records, 0, "Number of profiling records");
168 static int mutex_prof_maxrecords = NUM_MPROF_BUFFERS;
169 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, maxrecords, CTLFLAG_RD,
170 &mutex_prof_maxrecords, 0, "Maximum number of profiling records");
171 static int mutex_prof_rejected;
172 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, rejected, CTLFLAG_RD,
173 &mutex_prof_rejected, 0, "Number of rejected profiling records");
174 static int mutex_prof_hashsize = MPROF_HASH_SIZE;
175 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, hashsize, CTLFLAG_RD,
176 &mutex_prof_hashsize, 0, "Hash size");
177 static int mutex_prof_collisions = 0;
178 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, collisions, CTLFLAG_RD,
179 &mutex_prof_collisions, 0, "Number of hash collisions");
182 * mprof_mtx protects the profiling buffers and the hash.
184 static struct mtx mprof_mtx;
185 MTX_SYSINIT(mprof, &mprof_mtx, "mutex profiling lock", MTX_SPIN | MTX_QUIET);
193 return (tv.tv_sec * (u_int64_t)1000000000 + tv.tv_nsec);
197 dump_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
201 static int multiplier = 1;
203 if (first_free_mprof_buf == 0)
204 return (SYSCTL_OUT(req, "No locking recorded",
205 sizeof("No locking recorded")));
208 sb = sbuf_new(NULL, NULL, MPROF_SBUF_SIZE * multiplier, SBUF_FIXEDLEN);
209 sbuf_printf(sb, "\n%6s %12s %11s %5s %12s %12s %s\n",
210 "max", "total", "count", "avg", "cnt_hold", "cnt_lock", "name");
212 * XXX this spinlock seems to be by far the largest perpetrator
213 * of spinlock latency (1.6 msec on an Athlon1600 was recorded
214 * even before I pessimized it further by moving the average
217 mtx_lock_spin(&mprof_mtx);
218 for (i = 0; i < first_free_mprof_buf; ++i) {
219 sbuf_printf(sb, "%6ju %12ju %11ju %5ju %12ju %12ju %s:%d (%s)\n",
220 mprof_buf[i].cnt_max / 1000,
221 mprof_buf[i].cnt_tot / 1000,
222 mprof_buf[i].cnt_cur,
223 mprof_buf[i].cnt_cur == 0 ? (uintmax_t)0 :
224 mprof_buf[i].cnt_tot / (mprof_buf[i].cnt_cur * 1000),
225 mprof_buf[i].cnt_contest_holding,
226 mprof_buf[i].cnt_contest_locking,
227 mprof_buf[i].file, mprof_buf[i].line, mprof_buf[i].name);
228 if (sbuf_overflowed(sb)) {
229 mtx_unlock_spin(&mprof_mtx);
235 mtx_unlock_spin(&mprof_mtx);
237 error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
241 SYSCTL_PROC(_debug_mutex_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD,
242 NULL, 0, dump_mutex_prof_stats, "A", "Mutex profiling statistics");
245 reset_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
249 if (first_free_mprof_buf == 0)
253 error = sysctl_handle_int(oidp, &v, 0, req);
256 if (req->newptr == NULL)
261 mtx_lock_spin(&mprof_mtx);
262 bzero(mprof_buf, sizeof(*mprof_buf) * first_free_mprof_buf);
263 bzero(mprof_hash, sizeof(struct mtx *) * MPROF_HASH_SIZE);
264 first_free_mprof_buf = 0;
265 mtx_unlock_spin(&mprof_mtx);
268 SYSCTL_PROC(_debug_mutex_prof, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW,
269 NULL, 0, reset_mutex_prof_stats, "I", "Reset mutex profiling statistics");
273 * Function versions of the inlined __mtx_* macros. These are used by
274 * modules and can also be called from assembly language if needed.
277 _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line)
280 MPASS(curthread != NULL);
281 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_sleep,
282 ("mtx_lock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name,
284 WITNESS_CHECKORDER(&m->mtx_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE,
286 _get_sleep_lock(m, curthread, opts, file, line);
287 LOCK_LOG_LOCK("LOCK", &m->mtx_object, opts, m->mtx_recurse, file,
289 WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line);
290 #ifdef MUTEX_PROFILING
291 /* don't reset the timer when/if recursing */
292 if (m->mtx_acqtime == 0) {
293 m->mtx_filename = file;
294 m->mtx_lineno = line;
295 m->mtx_acqtime = mutex_prof_enable ? nanoseconds() : 0;
296 ++mutex_prof_acquisitions;
302 _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
305 MPASS(curthread != NULL);
306 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_sleep,
307 ("mtx_unlock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name,
309 WITNESS_UNLOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line);
310 LOCK_LOG_LOCK("UNLOCK", &m->mtx_object, opts, m->mtx_recurse, file,
312 mtx_assert(m, MA_OWNED);
313 #ifdef MUTEX_PROFILING
314 if (m->mtx_acqtime != 0) {
315 static const char *unknown = "(unknown)";
316 struct mutex_prof *mpp;
317 u_int64_t acqtime, now;
322 acqtime = m->mtx_acqtime;
326 for (p = m->mtx_filename;
327 p != NULL && strncmp(p, "../", 3) == 0; p += 3)
329 if (p == NULL || *p == '\0')
331 for (hash = m->mtx_lineno, q = p; *q != '\0'; ++q)
332 hash = (hash * 2 + *q) % MPROF_HASH_SIZE;
333 mtx_lock_spin(&mprof_mtx);
334 for (mpp = mprof_hash[hash]; mpp != NULL; mpp = mpp->next)
335 if (mpp->line == m->mtx_lineno &&
336 strcmp(mpp->file, p) == 0)
339 /* Just exit if we cannot get a trace buffer */
340 if (first_free_mprof_buf >= NUM_MPROF_BUFFERS) {
341 ++mutex_prof_rejected;
344 mpp = &mprof_buf[first_free_mprof_buf++];
345 mpp->name = mtx_name(m);
347 mpp->line = m->mtx_lineno;
348 mpp->next = mprof_hash[hash];
349 if (mprof_hash[hash] != NULL)
350 ++mutex_prof_collisions;
351 mprof_hash[hash] = mpp;
352 ++mutex_prof_records;
355 * Record if the mutex has been held longer now than ever
358 if (now - acqtime > mpp->cnt_max)
359 mpp->cnt_max = now - acqtime;
360 mpp->cnt_tot += now - acqtime;
363 * There's a small race, really we should cmpxchg
364 * 0 with the current value, but that would bill
365 * the contention to the wrong lock instance if
366 * it followed this also.
368 mpp->cnt_contest_holding += m->mtx_contest_holding;
369 m->mtx_contest_holding = 0;
370 mpp->cnt_contest_locking += m->mtx_contest_locking;
371 m->mtx_contest_locking = 0;
373 mtx_unlock_spin(&mprof_mtx);
377 _rel_sleep_lock(m, curthread, opts, file, line);
381 _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file, int line)
384 MPASS(curthread != NULL);
385 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_spin,
386 ("mtx_lock_spin() of sleep mutex %s @ %s:%d",
387 m->mtx_object.lo_name, file, line));
388 WITNESS_CHECKORDER(&m->mtx_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE,
390 _get_spin_lock(m, curthread, opts, file, line);
391 LOCK_LOG_LOCK("LOCK", &m->mtx_object, opts, m->mtx_recurse, file,
393 WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line);
397 _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file, int line)
400 MPASS(curthread != NULL);
401 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_spin,
402 ("mtx_unlock_spin() of sleep mutex %s @ %s:%d",
403 m->mtx_object.lo_name, file, line));
404 WITNESS_UNLOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line);
405 LOCK_LOG_LOCK("UNLOCK", &m->mtx_object, opts, m->mtx_recurse, file,
407 mtx_assert(m, MA_OWNED);
412 * The important part of mtx_trylock{,_flags}()
413 * Tries to acquire lock `m.' If this function is called on a mutex that
414 * is already owned, it will recursively acquire the lock.
417 _mtx_trylock(struct mtx *m, int opts, const char *file, int line)
421 MPASS(curthread != NULL);
422 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_sleep,
423 ("mtx_trylock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name,
426 if (mtx_owned(m) && (m->mtx_object.lo_flags & LO_RECURSABLE) != 0) {
428 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
431 rval = _obtain_lock(m, (uintptr_t)curthread);
433 LOCK_LOG_TRY("LOCK", &m->mtx_object, opts, rval, file, line);
435 WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK,
442 * _mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock.
444 * We call this if the lock is either contested (i.e. we need to go to
445 * sleep waiting for it), or if we need to recurse on it.
448 _mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts, const char *file,
451 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES)
452 struct thread *owner;
458 #ifdef MUTEX_PROFILING
463 KASSERT((m->mtx_object.lo_flags & LO_RECURSABLE) != 0,
464 ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n",
465 m->mtx_object.lo_name, file, line));
467 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
468 if (LOCK_LOG_TEST(&m->mtx_object, opts))
469 CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m);
473 if (LOCK_LOG_TEST(&m->mtx_object, opts))
475 "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d",
476 m->mtx_object.lo_name, (void *)m->mtx_lock, file, line);
478 #ifdef MUTEX_PROFILING
481 while (!_obtain_lock(m, tid)) {
482 #ifdef MUTEX_PROFILING
484 atomic_add_int(&m->mtx_contest_holding, 1);
486 turnstile_lock(&m->mtx_object);
490 * Check if the lock has been released while spinning for
491 * the turnstile chain lock.
493 if (v == MTX_UNOWNED) {
494 turnstile_release(&m->mtx_object);
499 #ifdef MUTEX_WAKE_ALL
500 MPASS(v != MTX_CONTESTED);
503 * The mutex was marked contested on release. This means that
504 * there are other threads blocked on it. Grab ownership of
505 * it and propagate its priority to the current thread if
508 if (v == MTX_CONTESTED) {
509 m->mtx_lock = tid | MTX_CONTESTED;
510 turnstile_claim(&m->mtx_object);
516 * If the mutex isn't already contested and a failure occurs
517 * setting the contested bit, the mutex was either released
518 * or the state of the MTX_RECURSED bit changed.
520 if ((v & MTX_CONTESTED) == 0 &&
521 !atomic_cmpset_ptr(&m->mtx_lock, v, v | MTX_CONTESTED)) {
522 turnstile_release(&m->mtx_object);
527 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES)
529 * If the current owner of the lock is executing on another
530 * CPU, spin instead of blocking.
532 owner = (struct thread *)(v & MTX_FLAGMASK);
533 #ifdef ADAPTIVE_GIANT
534 if (TD_IS_RUNNING(owner)) {
536 if (m != &Giant && TD_IS_RUNNING(owner)) {
538 turnstile_release(&m->mtx_object);
539 while (mtx_owner(m) == owner && TD_IS_RUNNING(owner)) {
544 #endif /* SMP && !NO_ADAPTIVE_MUTEXES */
547 * We definitely must sleep for this lock.
549 mtx_assert(m, MA_NOTOWNED);
554 "contention: %p at %s:%d wants %s, taken by %s:%d",
555 (void *)tid, file, line, m->mtx_object.lo_name,
556 WITNESS_FILE(&m->mtx_object),
557 WITNESS_LINE(&m->mtx_object));
563 * Block on the turnstile.
565 turnstile_wait(&m->mtx_object, mtx_owner(m),
572 "contention end: %s acquired by %p at %s:%d",
573 m->mtx_object.lo_name, (void *)tid, file, line);
576 #ifdef MUTEX_PROFILING
578 m->mtx_contest_locking++;
579 m->mtx_contest_holding = 0;
586 * _mtx_lock_spin: the tougher part of acquiring an MTX_SPIN lock.
588 * This is only called if we need to actually spin for the lock. Recursion
592 _mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts, const char *file,
597 if (LOCK_LOG_TEST(&m->mtx_object, opts))
598 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m);
601 if (_obtain_lock(m, tid))
604 /* Give interrupts a chance while we spin. */
606 while (m->mtx_lock != MTX_UNOWNED) {
607 if (i++ < 10000000) {
613 else if (!kdb_active && !panicstr) {
614 printf("spin lock %s held by %p for > 5 seconds\n",
615 m->mtx_object.lo_name, (void *)m->mtx_lock);
617 witness_display_spinlock(&m->mtx_object,
620 panic("spin lock held too long");
627 if (LOCK_LOG_TEST(&m->mtx_object, opts))
628 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m);
635 * _mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock.
637 * We are only called here if the lock is recursed or contested (i.e. we
638 * need to wake up a blocked thread).
641 _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line)
643 struct turnstile *ts;
645 struct thread *td, *td1;
648 if (mtx_recursed(m)) {
649 if (--(m->mtx_recurse) == 0)
650 atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED);
651 if (LOCK_LOG_TEST(&m->mtx_object, opts))
652 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m);
656 turnstile_lock(&m->mtx_object);
657 ts = turnstile_lookup(&m->mtx_object);
658 if (LOCK_LOG_TEST(&m->mtx_object, opts))
659 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m);
661 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES)
663 _release_lock_quick(m);
664 if (LOCK_LOG_TEST(&m->mtx_object, opts))
665 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p no sleepers", m);
666 turnstile_release(&m->mtx_object);
674 td1 = turnstile_head(ts, TS_EXCLUSIVE_QUEUE);
676 #ifdef MUTEX_WAKE_ALL
677 turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE);
678 _release_lock_quick(m);
680 if (turnstile_signal(ts, TS_EXCLUSIVE_QUEUE)) {
681 _release_lock_quick(m);
682 if (LOCK_LOG_TEST(&m->mtx_object, opts))
683 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p not held", m);
685 m->mtx_lock = MTX_CONTESTED;
686 if (LOCK_LOG_TEST(&m->mtx_object, opts))
687 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p still contested",
691 turnstile_unpend(ts, TS_EXCLUSIVE_LOCK);
695 * XXX: This is just a hack until preemption is done. However,
696 * once preemption is done we need to either wrap the
697 * turnstile_signal() and release of the actual lock in an
698 * extra critical section or change the preemption code to
699 * always just set a flag and never do instant-preempts.
702 if (td->td_critnest > 0 || td1->td_priority >= td->td_priority)
704 mtx_lock_spin(&sched_lock);
705 if (!TD_IS_RUNNING(td1)) {
707 if (td->td_ithd != NULL) {
708 struct ithd *it = td->td_ithd;
710 if (it->it_interrupted) {
711 if (LOCK_LOG_TEST(&m->mtx_object, opts))
713 "_mtx_unlock_sleep: %p interrupted %p",
714 it, it->it_interrupted);
719 if (LOCK_LOG_TEST(&m->mtx_object, opts))
721 "_mtx_unlock_sleep: %p switching out lock=%p", m,
722 (void *)m->mtx_lock);
724 mi_switch(SW_INVOL, NULL);
725 if (LOCK_LOG_TEST(&m->mtx_object, opts))
726 CTR2(KTR_LOCK, "_mtx_unlock_sleep: %p resuming lock=%p",
727 m, (void *)m->mtx_lock);
729 mtx_unlock_spin(&sched_lock);
736 * All the unlocking of MTX_SPIN locks is done inline.
737 * See the _rel_spin_lock() macro for the details.
741 * The backing function for the INVARIANTS-enabled mtx_assert()
743 #ifdef INVARIANT_SUPPORT
745 _mtx_assert(struct mtx *m, int what, const char *file, int line)
748 if (panicstr != NULL || dumping)
752 case MA_OWNED | MA_RECURSED:
753 case MA_OWNED | MA_NOTRECURSED:
755 panic("mutex %s not owned at %s:%d",
756 m->mtx_object.lo_name, file, line);
757 if (mtx_recursed(m)) {
758 if ((what & MA_NOTRECURSED) != 0)
759 panic("mutex %s recursed at %s:%d",
760 m->mtx_object.lo_name, file, line);
761 } else if ((what & MA_RECURSED) != 0) {
762 panic("mutex %s unrecursed at %s:%d",
763 m->mtx_object.lo_name, file, line);
768 panic("mutex %s owned at %s:%d",
769 m->mtx_object.lo_name, file, line);
772 panic("unknown mtx_assert at %s:%d", file, line);
778 * The MUTEX_DEBUG-enabled mtx_validate()
780 * Most of these checks have been moved off into the LO_INITIALIZED flag
781 * maintained by the witness code.
785 void mtx_validate(struct mtx *);
788 mtx_validate(struct mtx *m)
792 * XXX: When kernacc() does not require Giant we can reenable this check
796 * XXX - When kernacc() is fixed on the alpha to handle K0_SEG memory properly
797 * we can re-enable the kernacc() checks.
801 * Can't call kernacc() from early init386(), especially when
802 * initializing Giant mutex, because some stuff in kernacc()
803 * requires Giant itself.
806 if (!kernacc((caddr_t)m, sizeof(m),
807 VM_PROT_READ | VM_PROT_WRITE))
808 panic("Can't read and write to mutex %p", m);
815 * General init routine used by the MTX_SYSINIT() macro.
818 mtx_sysinit(void *arg)
820 struct mtx_args *margs = arg;
822 mtx_init(margs->ma_mtx, margs->ma_desc, NULL, margs->ma_opts);
826 * Mutex initialization routine; initialize lock `m' of type contained in
827 * `opts' with options contained in `opts' and name `name.' The optional
828 * lock type `type' is used as a general lock category name for use with
832 mtx_init(struct mtx *m, const char *name, const char *type, int opts)
834 struct lock_class *class;
837 MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE |
838 MTX_NOWITNESS | MTX_DUPOK)) == 0);
841 /* Diagnostic and error correction */
845 /* Determine lock class and lock flags. */
847 class = &lock_class_mtx_spin;
849 class = &lock_class_mtx_sleep;
851 if (opts & MTX_QUIET)
853 if (opts & MTX_RECURSE)
854 flags |= LO_RECURSABLE;
855 if ((opts & MTX_NOWITNESS) == 0)
857 if (opts & MTX_DUPOK)
860 /* Initialize mutex. */
861 m->mtx_lock = MTX_UNOWNED;
863 #ifdef MUTEX_PROFILING
865 m->mtx_filename = NULL;
867 m->mtx_contest_holding = 0;
868 m->mtx_contest_locking = 0;
871 lock_init(&m->mtx_object, class, name, type, flags);
875 * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be
876 * passed in as a flag here because if the corresponding mtx_init() was
877 * called with MTX_QUIET set, then it will already be set in the mutex's
881 mtx_destroy(struct mtx *m)
885 MPASS(mtx_unowned(m));
887 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0);
889 /* Perform the non-mtx related part of mtx_unlock_spin(). */
890 if (LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_spin)
893 /* Tell witness this isn't locked to make it happy. */
894 WITNESS_UNLOCK(&m->mtx_object, LOP_EXCLUSIVE, __FILE__,
898 lock_destroy(&m->mtx_object);
902 * Intialize the mutex code and system mutexes. This is called from the MD
903 * startup code prior to mi_startup(). The per-CPU data space needs to be
904 * setup before this is called.
910 /* Setup turnstiles so that sleep mutexes work. */
914 * Initialize mutexes.
916 mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE);
917 mtx_init(&sched_lock, "sched lock", NULL, MTX_SPIN | MTX_RECURSE);
918 mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK);
919 mtx_init(&devmtx, "cdev", NULL, MTX_DEF);
925 db_show_mtx(struct lock_object *lock)
930 m = (struct mtx *)lock;
932 db_printf(" flags: {");
933 if (LOCK_CLASS(lock) == &lock_class_mtx_spin)
937 if (m->mtx_object.lo_flags & LO_RECURSABLE)
938 db_printf(", RECURSE");
939 if (m->mtx_object.lo_flags & LO_DUPOK)
940 db_printf(", DUPOK");
942 db_printf(" state: {");
944 db_printf("UNOWNED");
947 if (m->mtx_lock & MTX_CONTESTED)
948 db_printf(", CONTESTED");
949 if (m->mtx_lock & MTX_RECURSED)
950 db_printf(", RECURSED");
953 if (!mtx_unowned(m)) {
955 db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td,
956 td->td_tid, td->td_proc->p_pid, td->td_proc->p_comm);
958 db_printf(" recursed: %d\n", m->mtx_recurse);