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/cpu.h>
69 #include <fs/devfs/devfs_int.h>
72 #include <vm/vm_extern.h>
75 * Force MUTEX_WAKE_ALL for now.
76 * single thread wakeup needs fixes to avoid race conditions with
77 * priority inheritance.
79 #ifndef MUTEX_WAKE_ALL
80 #define MUTEX_WAKE_ALL
84 * Internal utility macros.
86 #define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED)
88 #define mtx_owner(m) ((struct thread *)((m)->mtx_lock & ~MTX_FLAGMASK))
91 static void db_show_mtx(struct lock_object *lock);
95 * Lock classes for sleep and spin mutexes.
97 struct lock_class lock_class_mtx_sleep = {
99 LC_SLEEPLOCK | LC_RECURSABLE,
104 struct lock_class lock_class_mtx_spin = {
106 LC_SPINLOCK | LC_RECURSABLE,
113 * System-wide mutexes
115 struct mtx sched_lock;
118 #ifdef MUTEX_PROFILING
119 SYSCTL_NODE(_debug, OID_AUTO, mutex, CTLFLAG_RD, NULL, "mutex debugging");
120 SYSCTL_NODE(_debug_mutex, OID_AUTO, prof, CTLFLAG_RD, NULL, "mutex profiling");
121 static int mutex_prof_enable = 0;
122 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, enable, CTLFLAG_RW,
123 &mutex_prof_enable, 0, "Enable tracing of mutex holdtime");
132 uintmax_t cnt_contest_holding;
133 uintmax_t cnt_contest_locking;
134 struct mutex_prof *next;
138 * mprof_buf is a static pool of profiling records to avoid possible
139 * reentrance of the memory allocation functions.
141 * Note: NUM_MPROF_BUFFERS must be smaller than MPROF_HASH_SIZE.
144 #define NUM_MPROF_BUFFERS MPROF_BUFFERS
146 #define NUM_MPROF_BUFFERS 1000
148 static struct mutex_prof mprof_buf[NUM_MPROF_BUFFERS];
149 static int first_free_mprof_buf;
150 #ifndef MPROF_HASH_SIZE
151 #define MPROF_HASH_SIZE 1009
153 #if NUM_MPROF_BUFFERS >= MPROF_HASH_SIZE
154 #error MPROF_BUFFERS must be larger than MPROF_HASH_SIZE
156 static struct mutex_prof *mprof_hash[MPROF_HASH_SIZE];
157 /* SWAG: sbuf size = avg stat. line size * number of locks */
158 #define MPROF_SBUF_SIZE 256 * 400
160 static int mutex_prof_acquisitions;
161 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, acquisitions, CTLFLAG_RD,
162 &mutex_prof_acquisitions, 0, "Number of mutex acquistions recorded");
163 static int mutex_prof_records;
164 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, records, CTLFLAG_RD,
165 &mutex_prof_records, 0, "Number of profiling records");
166 static int mutex_prof_maxrecords = NUM_MPROF_BUFFERS;
167 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, maxrecords, CTLFLAG_RD,
168 &mutex_prof_maxrecords, 0, "Maximum number of profiling records");
169 static int mutex_prof_rejected;
170 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, rejected, CTLFLAG_RD,
171 &mutex_prof_rejected, 0, "Number of rejected profiling records");
172 static int mutex_prof_hashsize = MPROF_HASH_SIZE;
173 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, hashsize, CTLFLAG_RD,
174 &mutex_prof_hashsize, 0, "Hash size");
175 static int mutex_prof_collisions = 0;
176 SYSCTL_INT(_debug_mutex_prof, OID_AUTO, collisions, CTLFLAG_RD,
177 &mutex_prof_collisions, 0, "Number of hash collisions");
180 * mprof_mtx protects the profiling buffers and the hash.
182 static struct mtx mprof_mtx;
183 MTX_SYSINIT(mprof, &mprof_mtx, "mutex profiling lock", MTX_SPIN | MTX_QUIET);
191 return (tv.tv_sec * (u_int64_t)1000000000 + tv.tv_nsec);
195 dump_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
199 static int multiplier = 1;
201 if (first_free_mprof_buf == 0)
202 return (SYSCTL_OUT(req, "No locking recorded",
203 sizeof("No locking recorded")));
206 sb = sbuf_new(NULL, NULL, MPROF_SBUF_SIZE * multiplier, SBUF_FIXEDLEN);
207 sbuf_printf(sb, "\n%6s %12s %11s %5s %12s %12s %s\n",
208 "max", "total", "count", "avg", "cnt_hold", "cnt_lock", "name");
210 * XXX this spinlock seems to be by far the largest perpetrator
211 * of spinlock latency (1.6 msec on an Athlon1600 was recorded
212 * even before I pessimized it further by moving the average
215 mtx_lock_spin(&mprof_mtx);
216 for (i = 0; i < first_free_mprof_buf; ++i) {
217 sbuf_printf(sb, "%6ju %12ju %11ju %5ju %12ju %12ju %s:%d (%s)\n",
218 mprof_buf[i].cnt_max / 1000,
219 mprof_buf[i].cnt_tot / 1000,
220 mprof_buf[i].cnt_cur,
221 mprof_buf[i].cnt_cur == 0 ? (uintmax_t)0 :
222 mprof_buf[i].cnt_tot / (mprof_buf[i].cnt_cur * 1000),
223 mprof_buf[i].cnt_contest_holding,
224 mprof_buf[i].cnt_contest_locking,
225 mprof_buf[i].file, mprof_buf[i].line, mprof_buf[i].name);
226 if (sbuf_overflowed(sb)) {
227 mtx_unlock_spin(&mprof_mtx);
233 mtx_unlock_spin(&mprof_mtx);
235 error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
239 SYSCTL_PROC(_debug_mutex_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD,
240 NULL, 0, dump_mutex_prof_stats, "A", "Mutex profiling statistics");
243 reset_mutex_prof_stats(SYSCTL_HANDLER_ARGS)
247 if (first_free_mprof_buf == 0)
251 error = sysctl_handle_int(oidp, &v, 0, req);
254 if (req->newptr == NULL)
259 mtx_lock_spin(&mprof_mtx);
260 bzero(mprof_buf, sizeof(*mprof_buf) * first_free_mprof_buf);
261 bzero(mprof_hash, sizeof(struct mtx *) * MPROF_HASH_SIZE);
262 first_free_mprof_buf = 0;
263 mtx_unlock_spin(&mprof_mtx);
266 SYSCTL_PROC(_debug_mutex_prof, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW,
267 NULL, 0, reset_mutex_prof_stats, "I", "Reset mutex profiling statistics");
271 * Function versions of the inlined __mtx_* macros. These are used by
272 * modules and can also be called from assembly language if needed.
275 _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line)
278 MPASS(curthread != NULL);
279 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_sleep,
280 ("mtx_lock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name,
282 WITNESS_CHECKORDER(&m->mtx_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE,
284 _get_sleep_lock(m, curthread, opts, file, line);
285 LOCK_LOG_LOCK("LOCK", &m->mtx_object, opts, m->mtx_recurse, file,
287 WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line);
288 #ifdef MUTEX_PROFILING
289 /* don't reset the timer when/if recursing */
290 if (m->mtx_acqtime == 0) {
291 m->mtx_filename = file;
292 m->mtx_lineno = line;
293 m->mtx_acqtime = mutex_prof_enable ? nanoseconds() : 0;
294 ++mutex_prof_acquisitions;
300 _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line)
303 MPASS(curthread != NULL);
304 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_sleep,
305 ("mtx_unlock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name,
307 WITNESS_UNLOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line);
308 LOCK_LOG_LOCK("UNLOCK", &m->mtx_object, opts, m->mtx_recurse, file,
310 mtx_assert(m, MA_OWNED);
311 #ifdef MUTEX_PROFILING
312 if (m->mtx_acqtime != 0) {
313 static const char *unknown = "(unknown)";
314 struct mutex_prof *mpp;
315 u_int64_t acqtime, now;
320 acqtime = m->mtx_acqtime;
324 for (p = m->mtx_filename;
325 p != NULL && strncmp(p, "../", 3) == 0; p += 3)
327 if (p == NULL || *p == '\0')
329 for (hash = m->mtx_lineno, q = p; *q != '\0'; ++q)
330 hash = (hash * 2 + *q) % MPROF_HASH_SIZE;
331 mtx_lock_spin(&mprof_mtx);
332 for (mpp = mprof_hash[hash]; mpp != NULL; mpp = mpp->next)
333 if (mpp->line == m->mtx_lineno &&
334 strcmp(mpp->file, p) == 0)
337 /* Just exit if we cannot get a trace buffer */
338 if (first_free_mprof_buf >= NUM_MPROF_BUFFERS) {
339 ++mutex_prof_rejected;
342 mpp = &mprof_buf[first_free_mprof_buf++];
343 mpp->name = mtx_name(m);
345 mpp->line = m->mtx_lineno;
346 mpp->next = mprof_hash[hash];
347 if (mprof_hash[hash] != NULL)
348 ++mutex_prof_collisions;
349 mprof_hash[hash] = mpp;
350 ++mutex_prof_records;
353 * Record if the mutex has been held longer now than ever
356 if (now - acqtime > mpp->cnt_max)
357 mpp->cnt_max = now - acqtime;
358 mpp->cnt_tot += now - acqtime;
361 * There's a small race, really we should cmpxchg
362 * 0 with the current value, but that would bill
363 * the contention to the wrong lock instance if
364 * it followed this also.
366 mpp->cnt_contest_holding += m->mtx_contest_holding;
367 m->mtx_contest_holding = 0;
368 mpp->cnt_contest_locking += m->mtx_contest_locking;
369 m->mtx_contest_locking = 0;
371 mtx_unlock_spin(&mprof_mtx);
375 _rel_sleep_lock(m, curthread, opts, file, line);
379 _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file, int line)
382 MPASS(curthread != NULL);
383 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_spin,
384 ("mtx_lock_spin() of sleep mutex %s @ %s:%d",
385 m->mtx_object.lo_name, file, line));
386 WITNESS_CHECKORDER(&m->mtx_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE,
388 _get_spin_lock(m, curthread, opts, file, line);
389 LOCK_LOG_LOCK("LOCK", &m->mtx_object, opts, m->mtx_recurse, file,
391 WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line);
395 _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file, int line)
398 MPASS(curthread != NULL);
399 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_spin,
400 ("mtx_unlock_spin() of sleep mutex %s @ %s:%d",
401 m->mtx_object.lo_name, file, line));
402 WITNESS_UNLOCK(&m->mtx_object, opts | LOP_EXCLUSIVE, file, line);
403 LOCK_LOG_LOCK("UNLOCK", &m->mtx_object, opts, m->mtx_recurse, file,
405 mtx_assert(m, MA_OWNED);
410 * The important part of mtx_trylock{,_flags}()
411 * Tries to acquire lock `m.' If this function is called on a mutex that
412 * is already owned, it will recursively acquire the lock.
415 _mtx_trylock(struct mtx *m, int opts, const char *file, int line)
419 MPASS(curthread != NULL);
420 KASSERT(LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_sleep,
421 ("mtx_trylock() of spin mutex %s @ %s:%d", m->mtx_object.lo_name,
424 if (mtx_owned(m) && (m->mtx_object.lo_flags & LO_RECURSABLE) != 0) {
426 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
429 rval = _obtain_lock(m, (uintptr_t)curthread);
431 LOCK_LOG_TRY("LOCK", &m->mtx_object, opts, rval, file, line);
433 WITNESS_LOCK(&m->mtx_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK,
440 * _mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock.
442 * We call this if the lock is either contested (i.e. we need to go to
443 * sleep waiting for it), or if we need to recurse on it.
446 _mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts, const char *file,
449 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES)
450 volatile struct thread *owner;
456 #ifdef MUTEX_PROFILING
461 KASSERT((m->mtx_object.lo_flags & LO_RECURSABLE) != 0,
462 ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n",
463 m->mtx_object.lo_name, file, line));
465 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
466 if (LOCK_LOG_TEST(&m->mtx_object, opts))
467 CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m);
471 if (LOCK_LOG_TEST(&m->mtx_object, opts))
473 "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d",
474 m->mtx_object.lo_name, (void *)m->mtx_lock, file, line);
476 #ifdef MUTEX_PROFILING
479 while (!_obtain_lock(m, tid)) {
480 #ifdef MUTEX_PROFILING
482 atomic_add_int(&m->mtx_contest_holding, 1);
484 turnstile_lock(&m->mtx_object);
488 * Check if the lock has been released while spinning for
489 * the turnstile chain lock.
491 if (v == MTX_UNOWNED) {
492 turnstile_release(&m->mtx_object);
497 #ifdef MUTEX_WAKE_ALL
498 MPASS(v != MTX_CONTESTED);
501 * The mutex was marked contested on release. This means that
502 * there are other threads blocked on it. Grab ownership of
503 * it and propagate its priority to the current thread if
506 if (v == MTX_CONTESTED) {
507 m->mtx_lock = tid | MTX_CONTESTED;
508 turnstile_claim(&m->mtx_object);
514 * If the mutex isn't already contested and a failure occurs
515 * setting the contested bit, the mutex was either released
516 * or the state of the MTX_RECURSED bit changed.
518 if ((v & MTX_CONTESTED) == 0 &&
519 !atomic_cmpset_ptr(&m->mtx_lock, v, v | MTX_CONTESTED)) {
520 turnstile_release(&m->mtx_object);
525 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES)
527 * If the current owner of the lock is executing on another
528 * CPU, spin instead of blocking.
530 owner = (struct thread *)(v & ~MTX_FLAGMASK);
531 #ifdef ADAPTIVE_GIANT
532 if (TD_IS_RUNNING(owner)) {
534 if (m != &Giant && TD_IS_RUNNING(owner)) {
536 turnstile_release(&m->mtx_object);
537 while (mtx_owner(m) == owner && TD_IS_RUNNING(owner)) {
542 #endif /* SMP && !NO_ADAPTIVE_MUTEXES */
545 * We definitely must sleep for this lock.
547 mtx_assert(m, MA_NOTOWNED);
552 "contention: %p at %s:%d wants %s, taken by %s:%d",
553 (void *)tid, file, line, m->mtx_object.lo_name,
554 WITNESS_FILE(&m->mtx_object),
555 WITNESS_LINE(&m->mtx_object));
561 * Block on the turnstile.
563 turnstile_wait(&m->mtx_object, mtx_owner(m),
570 "contention end: %s acquired by %p at %s:%d",
571 m->mtx_object.lo_name, (void *)tid, file, line);
574 #ifdef MUTEX_PROFILING
576 m->mtx_contest_locking++;
577 m->mtx_contest_holding = 0;
584 * _mtx_lock_spin: the tougher part of acquiring an MTX_SPIN lock.
586 * This is only called if we need to actually spin for the lock. Recursion
590 _mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts, const char *file,
595 if (LOCK_LOG_TEST(&m->mtx_object, opts))
596 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m);
598 while (!_obtain_lock(m, tid)) {
600 /* Give interrupts a chance while we spin. */
602 while (m->mtx_lock != MTX_UNOWNED) {
603 if (i++ < 10000000) {
609 else if (!kdb_active && !panicstr) {
610 printf("spin lock %s held by %p for > 5 seconds\n",
611 m->mtx_object.lo_name, (void *)m->mtx_lock);
613 witness_display_spinlock(&m->mtx_object,
616 panic("spin lock held too long");
623 if (LOCK_LOG_TEST(&m->mtx_object, opts))
624 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m);
631 * _mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock.
633 * We are only called here if the lock is recursed or contested (i.e. we
634 * need to wake up a blocked thread).
637 _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line)
639 struct turnstile *ts;
641 struct thread *td, *td1;
644 if (mtx_recursed(m)) {
645 if (--(m->mtx_recurse) == 0)
646 atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED);
647 if (LOCK_LOG_TEST(&m->mtx_object, opts))
648 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m);
652 turnstile_lock(&m->mtx_object);
653 ts = turnstile_lookup(&m->mtx_object);
654 if (LOCK_LOG_TEST(&m->mtx_object, opts))
655 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m);
657 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES)
659 _release_lock_quick(m);
660 if (LOCK_LOG_TEST(&m->mtx_object, opts))
661 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p no sleepers", m);
662 turnstile_release(&m->mtx_object);
670 td1 = turnstile_head(ts, TS_EXCLUSIVE_QUEUE);
672 #ifdef MUTEX_WAKE_ALL
673 turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE);
674 _release_lock_quick(m);
676 if (turnstile_signal(ts, TS_EXCLUSIVE_QUEUE)) {
677 _release_lock_quick(m);
678 if (LOCK_LOG_TEST(&m->mtx_object, opts))
679 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p not held", m);
681 m->mtx_lock = MTX_CONTESTED;
682 if (LOCK_LOG_TEST(&m->mtx_object, opts))
683 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p still contested",
687 turnstile_unpend(ts, TS_EXCLUSIVE_LOCK);
691 * XXX: This is just a hack until preemption is done. However,
692 * once preemption is done we need to either wrap the
693 * turnstile_signal() and release of the actual lock in an
694 * extra critical section or change the preemption code to
695 * always just set a flag and never do instant-preempts.
698 if (td->td_critnest > 0 || td1->td_priority >= td->td_priority)
700 mtx_lock_spin(&sched_lock);
701 if (!TD_IS_RUNNING(td1)) {
703 if (td->td_ithd != NULL) {
704 struct ithd *it = td->td_ithd;
706 if (it->it_interrupted) {
707 if (LOCK_LOG_TEST(&m->mtx_object, opts))
709 "_mtx_unlock_sleep: %p interrupted %p",
710 it, it->it_interrupted);
715 if (LOCK_LOG_TEST(&m->mtx_object, opts))
717 "_mtx_unlock_sleep: %p switching out lock=%p", m,
718 (void *)m->mtx_lock);
720 mi_switch(SW_INVOL, NULL);
721 if (LOCK_LOG_TEST(&m->mtx_object, opts))
722 CTR2(KTR_LOCK, "_mtx_unlock_sleep: %p resuming lock=%p",
723 m, (void *)m->mtx_lock);
725 mtx_unlock_spin(&sched_lock);
732 * All the unlocking of MTX_SPIN locks is done inline.
733 * See the _rel_spin_lock() macro for the details.
737 * The backing function for the INVARIANTS-enabled mtx_assert()
739 #ifdef INVARIANT_SUPPORT
741 _mtx_assert(struct mtx *m, int what, const char *file, int line)
744 if (panicstr != NULL || dumping)
748 case MA_OWNED | MA_RECURSED:
749 case MA_OWNED | MA_NOTRECURSED:
751 panic("mutex %s not owned at %s:%d",
752 m->mtx_object.lo_name, file, line);
753 if (mtx_recursed(m)) {
754 if ((what & MA_NOTRECURSED) != 0)
755 panic("mutex %s recursed at %s:%d",
756 m->mtx_object.lo_name, file, line);
757 } else if ((what & MA_RECURSED) != 0) {
758 panic("mutex %s unrecursed at %s:%d",
759 m->mtx_object.lo_name, file, line);
764 panic("mutex %s owned at %s:%d",
765 m->mtx_object.lo_name, file, line);
768 panic("unknown mtx_assert at %s:%d", file, line);
774 * The MUTEX_DEBUG-enabled mtx_validate()
776 * Most of these checks have been moved off into the LO_INITIALIZED flag
777 * maintained by the witness code.
781 void mtx_validate(struct mtx *);
784 mtx_validate(struct mtx *m)
788 * XXX: When kernacc() does not require Giant we can reenable this check
792 * Can't call kernacc() from early init386(), especially when
793 * initializing Giant mutex, because some stuff in kernacc()
794 * requires Giant itself.
797 if (!kernacc((caddr_t)m, sizeof(m),
798 VM_PROT_READ | VM_PROT_WRITE))
799 panic("Can't read and write to mutex %p", m);
805 * General init routine used by the MTX_SYSINIT() macro.
808 mtx_sysinit(void *arg)
810 struct mtx_args *margs = arg;
812 mtx_init(margs->ma_mtx, margs->ma_desc, NULL, margs->ma_opts);
816 * Mutex initialization routine; initialize lock `m' of type contained in
817 * `opts' with options contained in `opts' and name `name.' The optional
818 * lock type `type' is used as a general lock category name for use with
822 mtx_init(struct mtx *m, const char *name, const char *type, int opts)
824 struct lock_class *class;
827 MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE |
828 MTX_NOWITNESS | MTX_DUPOK)) == 0);
831 /* Diagnostic and error correction */
835 /* Determine lock class and lock flags. */
837 class = &lock_class_mtx_spin;
839 class = &lock_class_mtx_sleep;
841 if (opts & MTX_QUIET)
843 if (opts & MTX_RECURSE)
844 flags |= LO_RECURSABLE;
845 if ((opts & MTX_NOWITNESS) == 0)
847 if (opts & MTX_DUPOK)
850 /* Initialize mutex. */
851 m->mtx_lock = MTX_UNOWNED;
853 #ifdef MUTEX_PROFILING
855 m->mtx_filename = NULL;
857 m->mtx_contest_holding = 0;
858 m->mtx_contest_locking = 0;
861 lock_init(&m->mtx_object, class, name, type, flags);
865 * Remove lock `m' from all_mtx queue. We don't allow MTX_QUIET to be
866 * passed in as a flag here because if the corresponding mtx_init() was
867 * called with MTX_QUIET set, then it will already be set in the mutex's
871 mtx_destroy(struct mtx *m)
875 MPASS(mtx_unowned(m));
877 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0);
879 /* Perform the non-mtx related part of mtx_unlock_spin(). */
880 if (LOCK_CLASS(&m->mtx_object) == &lock_class_mtx_spin)
883 /* Tell witness this isn't locked to make it happy. */
884 WITNESS_UNLOCK(&m->mtx_object, LOP_EXCLUSIVE, __FILE__,
888 lock_destroy(&m->mtx_object);
892 * Intialize the mutex code and system mutexes. This is called from the MD
893 * startup code prior to mi_startup(). The per-CPU data space needs to be
894 * setup before this is called.
900 /* Setup turnstiles so that sleep mutexes work. */
904 * Initialize mutexes.
906 mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE);
907 mtx_init(&sched_lock, "sched lock", NULL, MTX_SPIN | MTX_RECURSE);
908 mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK);
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->mtx_object.lo_flags & LO_RECURSABLE)
928 db_printf(", RECURSE");
929 if (m->mtx_object.lo_flags & LO_DUPOK)
930 db_printf(", DUPOK");
932 db_printf(" state: {");
934 db_printf("UNOWNED");
937 if (m->mtx_lock & MTX_CONTESTED)
938 db_printf(", CONTESTED");
939 if (m->mtx_lock & MTX_RECURSED)
940 db_printf(", RECURSED");
943 if (!mtx_unowned(m)) {
945 db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td,
946 td->td_tid, td->td_proc->p_pid, td->td_proc->p_comm);
948 db_printf(" recursed: %d\n", m->mtx_recurse);