The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_mutex.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 1998 Berkeley Software Design, Inc. All rights reserved.
    3  *
    4  * Redistribution and use in source and binary forms, with or without
    5  * modification, are permitted provided that the following conditions
    6  * are met:
    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
   14  *    written permission.
   15  *
   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
   26  * SUCH DAMAGE.
   27  *
   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 $
   30  */
   31 
   32 /*
   33  * Machine independent bits of mutex implementation.
   34  */
   35 
   36 #include <sys/cdefs.h>
   37 __FBSDID("$FreeBSD$");
   38 
   39 #include "opt_adaptive_mutexes.h"
   40 #include "opt_ddb.h"
   41 #include "opt_hwpmc_hooks.h"
   42 #include "opt_sched.h"
   43 
   44 #include <sys/param.h>
   45 #include <sys/systm.h>
   46 #include <sys/bus.h>
   47 #include <sys/conf.h>
   48 #include <sys/kdb.h>
   49 #include <sys/kernel.h>
   50 #include <sys/ktr.h>
   51 #include <sys/lock.h>
   52 #include <sys/malloc.h>
   53 #include <sys/mutex.h>
   54 #include <sys/proc.h>
   55 #include <sys/resourcevar.h>
   56 #include <sys/sched.h>
   57 #include <sys/sbuf.h>
   58 #include <sys/smp.h>
   59 #include <sys/sysctl.h>
   60 #include <sys/turnstile.h>
   61 #include <sys/vmmeter.h>
   62 #include <sys/lock_profile.h>
   63 
   64 #include <machine/atomic.h>
   65 #include <machine/bus.h>
   66 #include <machine/cpu.h>
   67 
   68 #include <ddb/ddb.h>
   69 
   70 #include <fs/devfs/devfs_int.h>
   71 
   72 #include <vm/vm.h>
   73 #include <vm/vm_extern.h>
   74 
   75 #if defined(SMP) && !defined(NO_ADAPTIVE_MUTEXES)
   76 #define ADAPTIVE_MUTEXES
   77 #endif
   78 
   79 #ifdef HWPMC_HOOKS
   80 #include <sys/pmckern.h>
   81 PMC_SOFT_DEFINE( , , lock, failed);
   82 #endif
   83 
   84 /*
   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.
   87  */
   88 #define mtxlock2mtx(c)  (__containerof(c, struct mtx, mtx_lock))
   89 
   90 /*
   91  * Internal utility macros.
   92  */
   93 #define mtx_unowned(m)  ((m)->mtx_lock == MTX_UNOWNED)
   94 
   95 #define mtx_destroyed(m) ((m)->mtx_lock == MTX_DESTROYED)
   96 
   97 static void     assert_mtx(const struct lock_object *lock, int what);
   98 #ifdef DDB
   99 static void     db_show_mtx(const struct lock_object *lock);
  100 #endif
  101 static void     lock_mtx(struct lock_object *lock, uintptr_t how);
  102 static void     lock_spin(struct lock_object *lock, uintptr_t how);
  103 #ifdef KDTRACE_HOOKS
  104 static int      owner_mtx(const struct lock_object *lock,
  105                     struct thread **owner);
  106 #endif
  107 static uintptr_t unlock_mtx(struct lock_object *lock);
  108 static uintptr_t unlock_spin(struct lock_object *lock);
  109 
  110 /*
  111  * Lock classes for sleep and spin mutexes.
  112  */
  113 struct lock_class lock_class_mtx_sleep = {
  114         .lc_name = "sleep mutex",
  115         .lc_flags = LC_SLEEPLOCK | LC_RECURSABLE,
  116         .lc_assert = assert_mtx,
  117 #ifdef DDB
  118         .lc_ddb_show = db_show_mtx,
  119 #endif
  120         .lc_lock = lock_mtx,
  121         .lc_unlock = unlock_mtx,
  122 #ifdef KDTRACE_HOOKS
  123         .lc_owner = owner_mtx,
  124 #endif
  125 };
  126 struct lock_class lock_class_mtx_spin = {
  127         .lc_name = "spin mutex",
  128         .lc_flags = LC_SPINLOCK | LC_RECURSABLE,
  129         .lc_assert = assert_mtx,
  130 #ifdef DDB
  131         .lc_ddb_show = db_show_mtx,
  132 #endif
  133         .lc_lock = lock_spin,
  134         .lc_unlock = unlock_spin,
  135 #ifdef KDTRACE_HOOKS
  136         .lc_owner = owner_mtx,
  137 #endif
  138 };
  139 
  140 #ifdef ADAPTIVE_MUTEXES
  141 static SYSCTL_NODE(_debug, OID_AUTO, mtx, CTLFLAG_RD, NULL, "mtx debugging");
  142 
  143 static struct lock_delay_config __read_frequently mtx_delay;
  144 
  145 SYSCTL_INT(_debug_mtx, OID_AUTO, delay_base, CTLFLAG_RW, &mtx_delay.base,
  146     0, "");
  147 SYSCTL_INT(_debug_mtx, OID_AUTO, delay_max, CTLFLAG_RW, &mtx_delay.max,
  148     0, "");
  149 
  150 LOCK_DELAY_SYSINIT_DEFAULT(mtx_delay);
  151 #endif
  152 
  153 static SYSCTL_NODE(_debug, OID_AUTO, mtx_spin, CTLFLAG_RD, NULL,
  154     "mtx spin debugging");
  155 
  156 static struct lock_delay_config __read_frequently mtx_spin_delay;
  157 
  158 SYSCTL_INT(_debug_mtx_spin, OID_AUTO, delay_base, CTLFLAG_RW,
  159     &mtx_spin_delay.base, 0, "");
  160 SYSCTL_INT(_debug_mtx_spin, OID_AUTO, delay_max, CTLFLAG_RW,
  161     &mtx_spin_delay.max, 0, "");
  162 
  163 LOCK_DELAY_SYSINIT_DEFAULT(mtx_spin_delay);
  164 
  165 /*
  166  * System-wide mutexes
  167  */
  168 struct mtx blocked_lock;
  169 struct mtx Giant;
  170 
  171 static void _mtx_lock_indefinite_check(struct mtx *, struct lock_delay_arg *);
  172 
  173 void
  174 assert_mtx(const struct lock_object *lock, int what)
  175 {
  176 
  177         mtx_assert((const struct mtx *)lock, what);
  178 }
  179 
  180 void
  181 lock_mtx(struct lock_object *lock, uintptr_t how)
  182 {
  183 
  184         mtx_lock((struct mtx *)lock);
  185 }
  186 
  187 void
  188 lock_spin(struct lock_object *lock, uintptr_t how)
  189 {
  190 
  191         panic("spin locks can only use msleep_spin");
  192 }
  193 
  194 uintptr_t
  195 unlock_mtx(struct lock_object *lock)
  196 {
  197         struct mtx *m;
  198 
  199         m = (struct mtx *)lock;
  200         mtx_assert(m, MA_OWNED | MA_NOTRECURSED);
  201         mtx_unlock(m);
  202         return (0);
  203 }
  204 
  205 uintptr_t
  206 unlock_spin(struct lock_object *lock)
  207 {
  208 
  209         panic("spin locks can only use msleep_spin");
  210 }
  211 
  212 #ifdef KDTRACE_HOOKS
  213 int
  214 owner_mtx(const struct lock_object *lock, struct thread **owner)
  215 {
  216         const struct mtx *m;
  217         uintptr_t x;
  218 
  219         m = (const struct mtx *)lock;
  220         x = m->mtx_lock;
  221         *owner = (struct thread *)(x & ~MTX_FLAGMASK);
  222         return (*owner != NULL);
  223 }
  224 #endif
  225 
  226 /*
  227  * Function versions of the inlined __mtx_* macros.  These are used by
  228  * modules and can also be called from assembly language if needed.
  229  */
  230 void
  231 __mtx_lock_flags(volatile uintptr_t *c, int opts, const char *file, int line)
  232 {
  233         struct mtx *m;
  234         uintptr_t tid, v;
  235 
  236         m = mtxlock2mtx(c);
  237 
  238         KASSERT(kdb_active != 0 || SCHEDULER_STOPPED() ||
  239             !TD_IS_IDLETHREAD(curthread),
  240             ("mtx_lock() by idle thread %p on sleep mutex %s @ %s:%d",
  241             curthread, m->lock_object.lo_name, file, line));
  242         KASSERT(m->mtx_lock != MTX_DESTROYED,
  243             ("mtx_lock() of destroyed mutex @ %s:%d", file, line));
  244         KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
  245             ("mtx_lock() of spin mutex %s @ %s:%d", m->lock_object.lo_name,
  246             file, line));
  247         WITNESS_CHECKORDER(&m->lock_object, (opts & ~MTX_RECURSE) |
  248             LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL);
  249 
  250         tid = (uintptr_t)curthread;
  251         v = MTX_UNOWNED;
  252         if (!_mtx_obtain_lock_fetch(m, &v, tid))
  253                 _mtx_lock_sleep(m, v, opts, file, line);
  254         else
  255                 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire,
  256                     m, 0, 0, file, line);
  257         LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file,
  258             line);
  259         WITNESS_LOCK(&m->lock_object, (opts & ~MTX_RECURSE) | LOP_EXCLUSIVE,
  260             file, line);
  261         TD_LOCKS_INC(curthread);
  262 }
  263 
  264 void
  265 __mtx_unlock_flags(volatile uintptr_t *c, int opts, const char *file, int line)
  266 {
  267         struct mtx *m;
  268 
  269         m = mtxlock2mtx(c);
  270 
  271         KASSERT(m->mtx_lock != MTX_DESTROYED,
  272             ("mtx_unlock() of destroyed mutex @ %s:%d", file, line));
  273         KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
  274             ("mtx_unlock() of spin mutex %s @ %s:%d", m->lock_object.lo_name,
  275             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,
  278             line);
  279         mtx_assert(m, MA_OWNED);
  280 
  281 #ifdef LOCK_PROFILING
  282         __mtx_unlock_sleep(c, (uintptr_t)curthread, opts, file, line);
  283 #else
  284         __mtx_unlock(m, curthread, opts, file, line);
  285 #endif
  286         TD_LOCKS_DEC(curthread);
  287 }
  288 
  289 void
  290 __mtx_lock_spin_flags(volatile uintptr_t *c, int opts, const char *file,
  291     int line)
  292 {
  293         struct mtx *m;
  294 #ifdef SMP
  295         uintptr_t tid, v;
  296 #endif
  297 
  298         m = mtxlock2mtx(c);
  299 
  300         KASSERT(m->mtx_lock != MTX_DESTROYED,
  301             ("mtx_lock_spin() of destroyed mutex @ %s:%d", file, line));
  302         KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
  303             ("mtx_lock_spin() of sleep mutex %s @ %s:%d",
  304             m->lock_object.lo_name, file, line));
  305         if (mtx_owned(m))
  306                 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0 ||
  307                     (opts & MTX_RECURSE) != 0,
  308             ("mtx_lock_spin: recursed on non-recursive mutex %s @ %s:%d\n",
  309                     m->lock_object.lo_name, file, line));
  310         opts &= ~MTX_RECURSE;
  311         WITNESS_CHECKORDER(&m->lock_object, opts | LOP_NEWORDER | LOP_EXCLUSIVE,
  312             file, line, NULL);
  313 #ifdef SMP
  314         spinlock_enter();
  315         tid = (uintptr_t)curthread;
  316         v = MTX_UNOWNED;
  317         if (!_mtx_obtain_lock_fetch(m, &v, tid))
  318                 _mtx_lock_spin(m, v, opts, file, line);
  319         else
  320                 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire,
  321                     m, 0, 0, file, line);
  322 #else
  323         __mtx_lock_spin(m, curthread, opts, file, line);
  324 #endif
  325         LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file,
  326             line);
  327         WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
  328 }
  329 
  330 int
  331 __mtx_trylock_spin_flags(volatile uintptr_t *c, int opts, const char *file,
  332     int line)
  333 {
  334         struct mtx *m;
  335 
  336         if (SCHEDULER_STOPPED())
  337                 return (1);
  338 
  339         m = mtxlock2mtx(c);
  340 
  341         KASSERT(m->mtx_lock != MTX_DESTROYED,
  342             ("mtx_trylock_spin() of destroyed mutex @ %s:%d", file, line));
  343         KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
  344             ("mtx_trylock_spin() of sleep mutex %s @ %s:%d",
  345             m->lock_object.lo_name, file, line));
  346         KASSERT((opts & MTX_RECURSE) == 0,
  347             ("mtx_trylock_spin: unsupp. opt MTX_RECURSE on mutex %s @ %s:%d\n",
  348             m->lock_object.lo_name, file, line));
  349         if (__mtx_trylock_spin(m, curthread, opts, file, line)) {
  350                 LOCK_LOG_TRY("LOCK", &m->lock_object, opts, 1, file, line);
  351                 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
  352                 return (1);
  353         }
  354         LOCK_LOG_TRY("LOCK", &m->lock_object, opts, 0, file, line);
  355         return (0);
  356 }
  357 
  358 void
  359 __mtx_unlock_spin_flags(volatile uintptr_t *c, int opts, const char *file,
  360     int line)
  361 {
  362         struct mtx *m;
  363 
  364         m = mtxlock2mtx(c);
  365 
  366         KASSERT(m->mtx_lock != MTX_DESTROYED,
  367             ("mtx_unlock_spin() of destroyed mutex @ %s:%d", file, line));
  368         KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
  369             ("mtx_unlock_spin() of sleep mutex %s @ %s:%d",
  370             m->lock_object.lo_name, file, line));
  371         WITNESS_UNLOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
  372         LOCK_LOG_LOCK("UNLOCK", &m->lock_object, opts, m->mtx_recurse, file,
  373             line);
  374         mtx_assert(m, MA_OWNED);
  375 
  376         __mtx_unlock_spin(m);
  377 }
  378 
  379 /*
  380  * The important part of mtx_trylock{,_flags}()
  381  * Tries to acquire lock `m.'  If this function is called on a mutex that
  382  * is already owned, it will recursively acquire the lock.
  383  */
  384 int
  385 _mtx_trylock_flags_int(struct mtx *m, int opts LOCK_FILE_LINE_ARG_DEF)
  386 {
  387         struct thread *td;
  388         uintptr_t tid, v;
  389 #ifdef LOCK_PROFILING
  390         uint64_t waittime = 0;
  391         int contested = 0;
  392 #endif
  393         int rval;
  394         bool recursed;
  395 
  396         td = curthread;
  397         tid = (uintptr_t)td;
  398         if (SCHEDULER_STOPPED_TD(td))
  399                 return (1);
  400 
  401         KASSERT(kdb_active != 0 || !TD_IS_IDLETHREAD(td),
  402             ("mtx_trylock() by idle thread %p on sleep mutex %s @ %s:%d",
  403             curthread, m->lock_object.lo_name, file, line));
  404         KASSERT(m->mtx_lock != MTX_DESTROYED,
  405             ("mtx_trylock() of destroyed mutex @ %s:%d", file, line));
  406         KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
  407             ("mtx_trylock() of spin mutex %s @ %s:%d", m->lock_object.lo_name,
  408             file, line));
  409 
  410         rval = 1;
  411         recursed = false;
  412         v = MTX_UNOWNED;
  413         for (;;) {
  414                 if (_mtx_obtain_lock_fetch(m, &v, tid))
  415                         break;
  416                 if (v == MTX_UNOWNED)
  417                         continue;
  418                 if (v == tid &&
  419                     ((m->lock_object.lo_flags & LO_RECURSABLE) != 0 ||
  420                     (opts & MTX_RECURSE) != 0)) {
  421                         m->mtx_recurse++;
  422                         atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
  423                         recursed = true;
  424                         break;
  425                 }
  426                 rval = 0;
  427                 break;
  428         }
  429 
  430         opts &= ~MTX_RECURSE;
  431 
  432         LOCK_LOG_TRY("LOCK", &m->lock_object, opts, rval, file, line);
  433         if (rval) {
  434                 WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE | LOP_TRYLOCK,
  435                     file, line);
  436                 TD_LOCKS_INC(curthread);
  437                 if (!recursed)
  438                         LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire,
  439                             m, contested, waittime, file, line);
  440         }
  441 
  442         return (rval);
  443 }
  444 
  445 int
  446 _mtx_trylock_flags_(volatile uintptr_t *c, int opts, const char *file, int line)
  447 {
  448         struct mtx *m;
  449 
  450         m = mtxlock2mtx(c);
  451         return (_mtx_trylock_flags_int(m, opts LOCK_FILE_LINE_ARG));
  452 }
  453 
  454 /*
  455  * __mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock.
  456  *
  457  * We call this if the lock is either contested (i.e. we need to go to
  458  * sleep waiting for it), or if we need to recurse on it.
  459  */
  460 #if LOCK_DEBUG > 0
  461 void
  462 __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v, int opts, const char *file,
  463     int line)
  464 #else
  465 void
  466 __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v)
  467 #endif
  468 {
  469         struct thread *td;
  470         struct mtx *m;
  471         struct turnstile *ts;
  472         uintptr_t tid;
  473         struct thread *owner;
  474 #ifdef LOCK_PROFILING
  475         int contested = 0;
  476         uint64_t waittime = 0;
  477 #endif
  478 #if defined(ADAPTIVE_MUTEXES) || defined(KDTRACE_HOOKS)
  479         struct lock_delay_arg lda;
  480 #endif
  481 #ifdef KDTRACE_HOOKS
  482         u_int sleep_cnt = 0;
  483         int64_t sleep_time = 0;
  484         int64_t all_time = 0;
  485 #endif
  486 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING)
  487         int doing_lockprof;
  488 #endif
  489 
  490         td = curthread;
  491         tid = (uintptr_t)td;
  492         m = mtxlock2mtx(c);
  493 
  494 #ifdef KDTRACE_HOOKS
  495         if (LOCKSTAT_PROFILE_ENABLED(adaptive__acquire)) {
  496                 while (v == MTX_UNOWNED) {
  497                         if (_mtx_obtain_lock_fetch(m, &v, tid))
  498                                 goto out_lockstat;
  499                 }
  500                 doing_lockprof = 1;
  501                 all_time -= lockstat_nsecs(&m->lock_object);
  502         }
  503 #endif
  504 #ifdef LOCK_PROFILING
  505         doing_lockprof = 1;
  506 #endif
  507 
  508         if (SCHEDULER_STOPPED_TD(td))
  509                 return;
  510 
  511 #if defined(ADAPTIVE_MUTEXES)
  512         lock_delay_arg_init(&lda, &mtx_delay);
  513 #elif defined(KDTRACE_HOOKS)
  514         lock_delay_arg_init(&lda, NULL);
  515 #endif
  516 
  517         if (__predict_false(v == MTX_UNOWNED))
  518                 v = MTX_READ_VALUE(m);
  519 
  520         if (__predict_false(lv_mtx_owner(v) == td)) {
  521                 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0 ||
  522                     (opts & MTX_RECURSE) != 0,
  523             ("_mtx_lock_sleep: recursed on non-recursive mutex %s @ %s:%d\n",
  524                     m->lock_object.lo_name, file, line));
  525 #if LOCK_DEBUG > 0
  526                 opts &= ~MTX_RECURSE;
  527 #endif
  528                 m->mtx_recurse++;
  529                 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED);
  530                 if (LOCK_LOG_TEST(&m->lock_object, opts))
  531                         CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recursing", m);
  532                 return;
  533         }
  534 #if LOCK_DEBUG > 0
  535         opts &= ~MTX_RECURSE;
  536 #endif
  537 
  538 #ifdef HWPMC_HOOKS
  539         PMC_SOFT_CALL( , , lock, failed);
  540 #endif
  541         lock_profile_obtain_lock_failed(&m->lock_object,
  542                     &contested, &waittime);
  543         if (LOCK_LOG_TEST(&m->lock_object, opts))
  544                 CTR4(KTR_LOCK,
  545                     "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d",
  546                     m->lock_object.lo_name, (void *)m->mtx_lock, file, line);
  547 
  548         for (;;) {
  549                 if (v == MTX_UNOWNED) {
  550                         if (_mtx_obtain_lock_fetch(m, &v, tid))
  551                                 break;
  552                         continue;
  553                 }
  554 #ifdef KDTRACE_HOOKS
  555                 lda.spin_cnt++;
  556 #endif
  557 #ifdef ADAPTIVE_MUTEXES
  558                 /*
  559                  * If the owner is running on another CPU, spin until the
  560                  * owner stops running or the state of the lock changes.
  561                  */
  562                 owner = lv_mtx_owner(v);
  563                 if (TD_IS_RUNNING(owner)) {
  564                         if (LOCK_LOG_TEST(&m->lock_object, 0))
  565                                 CTR3(KTR_LOCK,
  566                                     "%s: spinning on %p held by %p",
  567                                     __func__, m, owner);
  568                         KTR_STATE1(KTR_SCHED, "thread",
  569                             sched_tdname((struct thread *)tid),
  570                             "spinning", "lockname:\"%s\"",
  571                             m->lock_object.lo_name);
  572                         do {
  573                                 lock_delay(&lda);
  574                                 v = MTX_READ_VALUE(m);
  575                                 owner = lv_mtx_owner(v);
  576                         } while (v != MTX_UNOWNED && TD_IS_RUNNING(owner));
  577                         KTR_STATE0(KTR_SCHED, "thread",
  578                             sched_tdname((struct thread *)tid),
  579                             "running");
  580                         continue;
  581                 }
  582 #endif
  583 
  584                 ts = turnstile_trywait(&m->lock_object);
  585                 v = MTX_READ_VALUE(m);
  586 retry_turnstile:
  587 
  588                 /*
  589                  * Check if the lock has been released while spinning for
  590                  * the turnstile chain lock.
  591                  */
  592                 if (v == MTX_UNOWNED) {
  593                         turnstile_cancel(ts);
  594                         continue;
  595                 }
  596 
  597 #ifdef ADAPTIVE_MUTEXES
  598                 /*
  599                  * The current lock owner might have started executing
  600                  * on another CPU (or the lock could have changed
  601                  * owners) while we were waiting on the turnstile
  602                  * chain lock.  If so, drop the turnstile lock and try
  603                  * again.
  604                  */
  605                 owner = lv_mtx_owner(v);
  606                 if (TD_IS_RUNNING(owner)) {
  607                         turnstile_cancel(ts);
  608                         continue;
  609                 }
  610 #endif
  611 
  612                 /*
  613                  * If the mutex isn't already contested and a failure occurs
  614                  * setting the contested bit, the mutex was either released
  615                  * or the state of the MTX_RECURSED bit changed.
  616                  */
  617                 if ((v & MTX_CONTESTED) == 0 &&
  618                     !atomic_fcmpset_ptr(&m->mtx_lock, &v, v | MTX_CONTESTED)) {
  619                         goto retry_turnstile;
  620                 }
  621 
  622                 /*
  623                  * We definitely must sleep for this lock.
  624                  */
  625                 mtx_assert(m, MA_NOTOWNED);
  626 
  627                 /*
  628                  * Block on the turnstile.
  629                  */
  630 #ifdef KDTRACE_HOOKS
  631                 sleep_time -= lockstat_nsecs(&m->lock_object);
  632 #endif
  633 #ifndef ADAPTIVE_MUTEXES
  634                 owner = mtx_owner(m);
  635 #endif
  636                 MPASS(owner == mtx_owner(m));
  637                 turnstile_wait(ts, owner, TS_EXCLUSIVE_QUEUE);
  638 #ifdef KDTRACE_HOOKS
  639                 sleep_time += lockstat_nsecs(&m->lock_object);
  640                 sleep_cnt++;
  641 #endif
  642                 v = MTX_READ_VALUE(m);
  643         }
  644 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING)
  645         if (__predict_true(!doing_lockprof))
  646                 return;
  647 #endif
  648 #ifdef KDTRACE_HOOKS
  649         all_time += lockstat_nsecs(&m->lock_object);
  650         if (sleep_time)
  651                 LOCKSTAT_RECORD1(adaptive__block, m, sleep_time);
  652 
  653         /*
  654          * Only record the loops spinning and not sleeping.
  655          */
  656         if (lda.spin_cnt > sleep_cnt)
  657                 LOCKSTAT_RECORD1(adaptive__spin, m, all_time - sleep_time);
  658 out_lockstat:
  659 #endif
  660         LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(adaptive__acquire, m, contested,
  661             waittime, file, line);
  662 }
  663 
  664 #ifdef SMP
  665 /*
  666  * _mtx_lock_spin_cookie: the tougher part of acquiring an MTX_SPIN lock.
  667  *
  668  * This is only called if we need to actually spin for the lock. Recursion
  669  * is handled inline.
  670  */
  671 #if LOCK_DEBUG > 0
  672 void
  673 _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v, int opts,
  674     const char *file, int line)
  675 #else
  676 void
  677 _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t v)
  678 #endif
  679 {
  680         struct mtx *m;
  681         struct lock_delay_arg lda;
  682         uintptr_t tid;
  683 #ifdef LOCK_PROFILING
  684         int contested = 0;
  685         uint64_t waittime = 0;
  686 #endif
  687 #ifdef KDTRACE_HOOKS
  688         int64_t spin_time = 0;
  689 #endif
  690 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING)
  691         int doing_lockprof;
  692 #endif
  693 
  694         tid = (uintptr_t)curthread;
  695         m = mtxlock2mtx(c);
  696 
  697 #ifdef KDTRACE_HOOKS
  698         if (LOCKSTAT_PROFILE_ENABLED(adaptive__acquire)) {
  699                 while (v == MTX_UNOWNED) {
  700                         if (_mtx_obtain_lock_fetch(m, &v, tid))
  701                                 goto out_lockstat;
  702                 }
  703                 doing_lockprof = 1;
  704                 spin_time -= lockstat_nsecs(&m->lock_object);
  705         }
  706 #endif
  707 #ifdef LOCK_PROFILING
  708         doing_lockprof = 1;
  709 #endif
  710 
  711         if (__predict_false(v == MTX_UNOWNED))
  712                 v = MTX_READ_VALUE(m);
  713 
  714         if (__predict_false(v == tid)) {
  715                 m->mtx_recurse++;
  716                 return;
  717         }
  718 
  719         if (SCHEDULER_STOPPED())
  720                 return;
  721 
  722         lock_delay_arg_init(&lda, &mtx_spin_delay);
  723 
  724         if (LOCK_LOG_TEST(&m->lock_object, opts))
  725                 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spinning", m);
  726         KTR_STATE1(KTR_SCHED, "thread", sched_tdname((struct thread *)tid),
  727             "spinning", "lockname:\"%s\"", m->lock_object.lo_name);
  728 
  729 #ifdef HWPMC_HOOKS
  730         PMC_SOFT_CALL( , , lock, failed);
  731 #endif
  732         lock_profile_obtain_lock_failed(&m->lock_object, &contested, &waittime);
  733 
  734         for (;;) {
  735                 if (v == MTX_UNOWNED) {
  736                         if (_mtx_obtain_lock_fetch(m, &v, tid))
  737                                 break;
  738                         continue;
  739                 }
  740                 /* Give interrupts a chance while we spin. */
  741                 spinlock_exit();
  742                 do {
  743                         if (__predict_true(lda.spin_cnt < 10000000)) {
  744                                 lock_delay(&lda);
  745                         } else {
  746                                 _mtx_lock_indefinite_check(m, &lda);
  747                         }
  748                         v = MTX_READ_VALUE(m);
  749                 } while (v != MTX_UNOWNED);
  750                 spinlock_enter();
  751         }
  752 
  753         if (LOCK_LOG_TEST(&m->lock_object, opts))
  754                 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m);
  755         KTR_STATE0(KTR_SCHED, "thread", sched_tdname((struct thread *)tid),
  756             "running");
  757 
  758 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING)
  759         if (__predict_true(!doing_lockprof))
  760                 return;
  761 #endif
  762 #ifdef KDTRACE_HOOKS
  763         spin_time += lockstat_nsecs(&m->lock_object);
  764         if (lda.spin_cnt != 0)
  765                 LOCKSTAT_RECORD1(spin__spin, m, spin_time);
  766 out_lockstat:
  767 #endif
  768         LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, m,
  769             contested, waittime, file, line);
  770 }
  771 #endif /* SMP */
  772 
  773 #ifdef INVARIANTS
  774 static void
  775 thread_lock_validate(struct mtx *m, int opts, const char *file, int line)
  776 {
  777 
  778         KASSERT(m->mtx_lock != MTX_DESTROYED,
  779             ("thread_lock() of destroyed mutex @ %s:%d", file, line));
  780         KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
  781             ("thread_lock() of sleep mutex %s @ %s:%d",
  782             m->lock_object.lo_name, file, line));
  783         if (mtx_owned(m))
  784                 KASSERT((m->lock_object.lo_flags & LO_RECURSABLE) != 0,
  785                     ("thread_lock: recursed on non-recursive mutex %s @ %s:%d\n",
  786                     m->lock_object.lo_name, file, line));
  787         WITNESS_CHECKORDER(&m->lock_object,
  788             opts | LOP_NEWORDER | LOP_EXCLUSIVE, file, line, NULL);
  789 }
  790 #else
  791 #define thread_lock_validate(m, opts, file, line) do { } while (0)
  792 #endif
  793 
  794 #ifndef LOCK_PROFILING
  795 #if LOCK_DEBUG > 0
  796 void
  797 _thread_lock(struct thread *td, int opts, const char *file, int line)
  798 #else
  799 void
  800 _thread_lock(struct thread *td)
  801 #endif
  802 {
  803         struct mtx *m;
  804         uintptr_t tid, v;
  805 
  806         tid = (uintptr_t)curthread;
  807 
  808         if (__predict_false(LOCKSTAT_PROFILE_ENABLED(spin__acquire)))
  809                 goto slowpath_noirq;
  810         spinlock_enter();
  811         m = td->td_lock;
  812         thread_lock_validate(m, 0, file, line);
  813         v = MTX_READ_VALUE(m);
  814         if (__predict_true(v == MTX_UNOWNED)) {
  815                 if (__predict_false(!_mtx_obtain_lock(m, tid)))
  816                         goto slowpath_unlocked;
  817         } else if (v == tid) {
  818                 m->mtx_recurse++;
  819         } else
  820                 goto slowpath_unlocked;
  821         if (__predict_true(m == td->td_lock)) {
  822                 WITNESS_LOCK(&m->lock_object, LOP_EXCLUSIVE, file, line);
  823                 return;
  824         }
  825         MPASS(m->mtx_recurse == 0);
  826         _mtx_release_lock_quick(m);
  827 slowpath_unlocked:
  828         spinlock_exit();
  829 slowpath_noirq:
  830 #if LOCK_DEBUG > 0
  831         thread_lock_flags_(td, opts, file, line);
  832 #else
  833         thread_lock_flags_(td, 0, 0, 0);
  834 #endif
  835 }
  836 #endif
  837 
  838 void
  839 thread_lock_flags_(struct thread *td, int opts, const char *file, int line)
  840 {
  841         struct mtx *m;
  842         uintptr_t tid, v;
  843         struct lock_delay_arg lda;
  844 #ifdef LOCK_PROFILING
  845         int contested = 0;
  846         uint64_t waittime = 0;
  847 #endif
  848 #ifdef KDTRACE_HOOKS
  849         int64_t spin_time = 0;
  850 #endif
  851 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING)
  852         int doing_lockprof = 1;
  853 #endif
  854 
  855         tid = (uintptr_t)curthread;
  856 
  857         if (SCHEDULER_STOPPED()) {
  858                 /*
  859                  * Ensure that spinlock sections are balanced even when the
  860                  * scheduler is stopped, since we may otherwise inadvertently
  861                  * re-enable interrupts while dumping core.
  862                  */
  863                 spinlock_enter();
  864                 return;
  865         }
  866 
  867         lock_delay_arg_init(&lda, &mtx_spin_delay);
  868 
  869 #ifdef HWPMC_HOOKS
  870         PMC_SOFT_CALL( , , lock, failed);
  871 #endif
  872 
  873 #ifdef LOCK_PROFILING
  874         doing_lockprof = 1;
  875 #elif defined(KDTRACE_HOOKS)
  876         doing_lockprof = lockstat_enabled;
  877         if (__predict_false(doing_lockprof))
  878                 spin_time -= lockstat_nsecs(&td->td_lock->lock_object);
  879 #endif
  880         spinlock_enter();
  881 
  882         for (;;) {
  883 retry:
  884                 m = td->td_lock;
  885                 thread_lock_validate(m, opts, file, line);
  886                 v = MTX_READ_VALUE(m);
  887                 for (;;) {
  888                         if (v == MTX_UNOWNED) {
  889                                 if (_mtx_obtain_lock_fetch(m, &v, tid))
  890                                         break;
  891                                 continue;
  892                         }
  893                         if (v == tid) {
  894                                 m->mtx_recurse++;
  895                                 MPASS(m == td->td_lock);
  896                                 break;
  897                         }
  898                         lock_profile_obtain_lock_failed(&m->lock_object,
  899                             &contested, &waittime);
  900                         /* Give interrupts a chance while we spin. */
  901                         spinlock_exit();
  902                         do {
  903                                 if (__predict_true(lda.spin_cnt < 10000000)) {
  904                                         lock_delay(&lda);
  905                                 } else {
  906                                         _mtx_lock_indefinite_check(m, &lda);
  907                                 }
  908                                 if (m != td->td_lock) {
  909                                         spinlock_enter();
  910                                         goto retry;
  911                                 }
  912                                 v = MTX_READ_VALUE(m);
  913                         } while (v != MTX_UNOWNED);
  914                         spinlock_enter();
  915                 }
  916                 if (m == td->td_lock)
  917                         break;
  918                 MPASS(m->mtx_recurse == 0);
  919                 _mtx_release_lock_quick(m);
  920         }
  921         LOCK_LOG_LOCK("LOCK", &m->lock_object, opts, m->mtx_recurse, file,
  922             line);
  923         WITNESS_LOCK(&m->lock_object, opts | LOP_EXCLUSIVE, file, line);
  924 
  925 #if defined(KDTRACE_HOOKS) || defined(LOCK_PROFILING)
  926         if (__predict_true(!doing_lockprof))
  927                 return;
  928 #endif
  929 #ifdef KDTRACE_HOOKS
  930         spin_time += lockstat_nsecs(&m->lock_object);
  931 #endif
  932         if (m->mtx_recurse == 0)
  933                 LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(spin__acquire, m,
  934                     contested, waittime, file, line);
  935 #ifdef KDTRACE_HOOKS
  936         if (lda.spin_cnt != 0)
  937                 LOCKSTAT_RECORD1(thread__spin, m, spin_time);
  938 #endif
  939 }
  940 
  941 struct mtx *
  942 thread_lock_block(struct thread *td)
  943 {
  944         struct mtx *lock;
  945 
  946         THREAD_LOCK_ASSERT(td, MA_OWNED);
  947         lock = td->td_lock;
  948         td->td_lock = &blocked_lock;
  949         mtx_unlock_spin(lock);
  950 
  951         return (lock);
  952 }
  953 
  954 void
  955 thread_lock_unblock(struct thread *td, struct mtx *new)
  956 {
  957         mtx_assert(new, MA_OWNED);
  958         MPASS(td->td_lock == &blocked_lock);
  959         atomic_store_rel_ptr((volatile void *)&td->td_lock, (uintptr_t)new);
  960 }
  961 
  962 void
  963 thread_lock_set(struct thread *td, struct mtx *new)
  964 {
  965         struct mtx *lock;
  966 
  967         mtx_assert(new, MA_OWNED);
  968         THREAD_LOCK_ASSERT(td, MA_OWNED);
  969         lock = td->td_lock;
  970         td->td_lock = new;
  971         mtx_unlock_spin(lock);
  972 }
  973 
  974 /*
  975  * __mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock.
  976  *
  977  * We are only called here if the lock is recursed, contested (i.e. we
  978  * need to wake up a blocked thread) or lockstat probe is active.
  979  */
  980 #if LOCK_DEBUG > 0
  981 void
  982 __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v, int opts,
  983     const char *file, int line)
  984 #else
  985 void
  986 __mtx_unlock_sleep(volatile uintptr_t *c, uintptr_t v)
  987 #endif
  988 {
  989         struct mtx *m;
  990         struct turnstile *ts;
  991         uintptr_t tid;
  992 
  993         if (SCHEDULER_STOPPED())
  994                 return;
  995 
  996         tid = (uintptr_t)curthread;
  997         m = mtxlock2mtx(c);
  998 
  999         if (__predict_false(v == tid))
 1000                 v = MTX_READ_VALUE(m);
 1001 
 1002         if (__predict_false(v & MTX_RECURSED)) {
 1003                 if (--(m->mtx_recurse) == 0)
 1004                         atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED);
 1005                 if (LOCK_LOG_TEST(&m->lock_object, opts))
 1006                         CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m);
 1007                 return;
 1008         }
 1009 
 1010         LOCKSTAT_PROFILE_RELEASE_LOCK(adaptive__release, m);
 1011         if (v == tid && _mtx_release_lock(m, tid))
 1012                 return;
 1013 
 1014         /*
 1015          * We have to lock the chain before the turnstile so this turnstile
 1016          * can be removed from the hash list if it is empty.
 1017          */
 1018         turnstile_chain_lock(&m->lock_object);
 1019         _mtx_release_lock_quick(m);
 1020         ts = turnstile_lookup(&m->lock_object);
 1021         MPASS(ts != NULL);
 1022         if (LOCK_LOG_TEST(&m->lock_object, opts))
 1023                 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m);
 1024         turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE);
 1025 
 1026         /*
 1027          * This turnstile is now no longer associated with the mutex.  We can
 1028          * unlock the chain lock so a new turnstile may take it's place.
 1029          */
 1030         turnstile_unpend(ts, TS_EXCLUSIVE_LOCK);
 1031         turnstile_chain_unlock(&m->lock_object);
 1032 }
 1033 
 1034 /*
 1035  * All the unlocking of MTX_SPIN locks is done inline.
 1036  * See the __mtx_unlock_spin() macro for the details.
 1037  */
 1038 
 1039 /*
 1040  * The backing function for the INVARIANTS-enabled mtx_assert()
 1041  */
 1042 #ifdef INVARIANT_SUPPORT
 1043 void
 1044 __mtx_assert(const volatile uintptr_t *c, int what, const char *file, int line)
 1045 {
 1046         const struct mtx *m;
 1047 
 1048         if (panicstr != NULL || dumping || SCHEDULER_STOPPED())
 1049                 return;
 1050 
 1051         m = mtxlock2mtx(c);
 1052 
 1053         switch (what) {
 1054         case MA_OWNED:
 1055         case MA_OWNED | MA_RECURSED:
 1056         case MA_OWNED | MA_NOTRECURSED:
 1057                 if (!mtx_owned(m))
 1058                         panic("mutex %s not owned at %s:%d",
 1059                             m->lock_object.lo_name, file, line);
 1060                 if (mtx_recursed(m)) {
 1061                         if ((what & MA_NOTRECURSED) != 0)
 1062                                 panic("mutex %s recursed at %s:%d",
 1063                                     m->lock_object.lo_name, file, line);
 1064                 } else if ((what & MA_RECURSED) != 0) {
 1065                         panic("mutex %s unrecursed at %s:%d",
 1066                             m->lock_object.lo_name, file, line);
 1067                 }
 1068                 break;
 1069         case MA_NOTOWNED:
 1070                 if (mtx_owned(m))
 1071                         panic("mutex %s owned at %s:%d",
 1072                             m->lock_object.lo_name, file, line);
 1073                 break;
 1074         default:
 1075                 panic("unknown mtx_assert at %s:%d", file, line);
 1076         }
 1077 }
 1078 #endif
 1079 
 1080 /*
 1081  * General init routine used by the MTX_SYSINIT() macro.
 1082  */
 1083 void
 1084 mtx_sysinit(void *arg)
 1085 {
 1086         struct mtx_args *margs = arg;
 1087 
 1088         mtx_init((struct mtx *)margs->ma_mtx, margs->ma_desc, NULL,
 1089             margs->ma_opts);
 1090 }
 1091 
 1092 /*
 1093  * Mutex initialization routine; initialize lock `m' of type contained in
 1094  * `opts' with options contained in `opts' and name `name.'  The optional
 1095  * lock type `type' is used as a general lock category name for use with
 1096  * witness.
 1097  */
 1098 void
 1099 _mtx_init(volatile uintptr_t *c, const char *name, const char *type, int opts)
 1100 {
 1101         struct mtx *m;
 1102         struct lock_class *class;
 1103         int flags;
 1104 
 1105         m = mtxlock2mtx(c);
 1106 
 1107         MPASS((opts & ~(MTX_SPIN | MTX_QUIET | MTX_RECURSE |
 1108             MTX_NOWITNESS | MTX_DUPOK | MTX_NOPROFILE | MTX_NEW)) == 0);
 1109         ASSERT_ATOMIC_LOAD_PTR(m->mtx_lock,
 1110             ("%s: mtx_lock not aligned for %s: %p", __func__, name,
 1111             &m->mtx_lock));
 1112 
 1113         /* Determine lock class and lock flags. */
 1114         if (opts & MTX_SPIN)
 1115                 class = &lock_class_mtx_spin;
 1116         else
 1117                 class = &lock_class_mtx_sleep;
 1118         flags = 0;
 1119         if (opts & MTX_QUIET)
 1120                 flags |= LO_QUIET;
 1121         if (opts & MTX_RECURSE)
 1122                 flags |= LO_RECURSABLE;
 1123         if ((opts & MTX_NOWITNESS) == 0)
 1124                 flags |= LO_WITNESS;
 1125         if (opts & MTX_DUPOK)
 1126                 flags |= LO_DUPOK;
 1127         if (opts & MTX_NOPROFILE)
 1128                 flags |= LO_NOPROFILE;
 1129         if (opts & MTX_NEW)
 1130                 flags |= LO_NEW;
 1131 
 1132         /* Initialize mutex. */
 1133         lock_init(&m->lock_object, class, name, type, flags);
 1134 
 1135         m->mtx_lock = MTX_UNOWNED;
 1136         m->mtx_recurse = 0;
 1137 }
 1138 
 1139 /*
 1140  * Remove lock `m' from all_mtx queue.  We don't allow MTX_QUIET to be
 1141  * passed in as a flag here because if the corresponding mtx_init() was
 1142  * called with MTX_QUIET set, then it will already be set in the mutex's
 1143  * flags.
 1144  */
 1145 void
 1146 _mtx_destroy(volatile uintptr_t *c)
 1147 {
 1148         struct mtx *m;
 1149 
 1150         m = mtxlock2mtx(c);
 1151 
 1152         if (!mtx_owned(m))
 1153                 MPASS(mtx_unowned(m));
 1154         else {
 1155                 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0);
 1156 
 1157                 /* Perform the non-mtx related part of mtx_unlock_spin(). */
 1158                 if (LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin)
 1159                         spinlock_exit();
 1160                 else
 1161                         TD_LOCKS_DEC(curthread);
 1162 
 1163                 lock_profile_release_lock(&m->lock_object);
 1164                 /* Tell witness this isn't locked to make it happy. */
 1165                 WITNESS_UNLOCK(&m->lock_object, LOP_EXCLUSIVE, __FILE__,
 1166                     __LINE__);
 1167         }
 1168 
 1169         m->mtx_lock = MTX_DESTROYED;
 1170         lock_destroy(&m->lock_object);
 1171 }
 1172 
 1173 /*
 1174  * Intialize the mutex code and system mutexes.  This is called from the MD
 1175  * startup code prior to mi_startup().  The per-CPU data space needs to be
 1176  * setup before this is called.
 1177  */
 1178 void
 1179 mutex_init(void)
 1180 {
 1181 
 1182         /* Setup turnstiles so that sleep mutexes work. */
 1183         init_turnstiles();
 1184 
 1185         /*
 1186          * Initialize mutexes.
 1187          */
 1188         mtx_init(&Giant, "Giant", NULL, MTX_DEF | MTX_RECURSE);
 1189         mtx_init(&blocked_lock, "blocked lock", NULL, MTX_SPIN);
 1190         blocked_lock.mtx_lock = 0xdeadc0de;     /* Always blocked. */
 1191         mtx_init(&proc0.p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK);
 1192         mtx_init(&proc0.p_slock, "process slock", NULL, MTX_SPIN);
 1193         mtx_init(&proc0.p_statmtx, "pstatl", NULL, MTX_SPIN);
 1194         mtx_init(&proc0.p_itimmtx, "pitiml", NULL, MTX_SPIN);
 1195         mtx_init(&proc0.p_profmtx, "pprofl", NULL, MTX_SPIN);
 1196         mtx_init(&devmtx, "cdev", NULL, MTX_DEF);
 1197         mtx_lock(&Giant);
 1198 }
 1199 
 1200 static void __noinline
 1201 _mtx_lock_indefinite_check(struct mtx *m, struct lock_delay_arg *ldap)
 1202 {
 1203         struct thread *td;
 1204 
 1205         ldap->spin_cnt++;
 1206         if (ldap->spin_cnt < 60000000 || kdb_active || panicstr != NULL)
 1207                 cpu_lock_delay();
 1208         else {
 1209                 td = mtx_owner(m);
 1210 
 1211                 /* If the mutex is unlocked, try again. */
 1212                 if (td == NULL)
 1213                         return;
 1214 
 1215                 printf( "spin lock %p (%s) held by %p (tid %d) too long\n",
 1216                     m, m->lock_object.lo_name, td, td->td_tid);
 1217 #ifdef WITNESS
 1218                 witness_display_spinlock(&m->lock_object, td, printf);
 1219 #endif
 1220                 panic("spin lock held too long");
 1221         }
 1222         cpu_spinwait();
 1223 }
 1224 
 1225 #ifdef DDB
 1226 void
 1227 db_show_mtx(const struct lock_object *lock)
 1228 {
 1229         struct thread *td;
 1230         const struct mtx *m;
 1231 
 1232         m = (const struct mtx *)lock;
 1233 
 1234         db_printf(" flags: {");
 1235         if (LOCK_CLASS(lock) == &lock_class_mtx_spin)
 1236                 db_printf("SPIN");
 1237         else
 1238                 db_printf("DEF");
 1239         if (m->lock_object.lo_flags & LO_RECURSABLE)
 1240                 db_printf(", RECURSE");
 1241         if (m->lock_object.lo_flags & LO_DUPOK)
 1242                 db_printf(", DUPOK");
 1243         db_printf("}\n");
 1244         db_printf(" state: {");
 1245         if (mtx_unowned(m))
 1246                 db_printf("UNOWNED");
 1247         else if (mtx_destroyed(m))
 1248                 db_printf("DESTROYED");
 1249         else {
 1250                 db_printf("OWNED");
 1251                 if (m->mtx_lock & MTX_CONTESTED)
 1252                         db_printf(", CONTESTED");
 1253                 if (m->mtx_lock & MTX_RECURSED)
 1254                         db_printf(", RECURSED");
 1255         }
 1256         db_printf("}\n");
 1257         if (!mtx_unowned(m) && !mtx_destroyed(m)) {
 1258                 td = mtx_owner(m);
 1259                 db_printf(" owner: %p (tid %d, pid %d, \"%s\")\n", td,
 1260                     td->td_tid, td->td_proc->p_pid, td->td_name);
 1261                 if (mtx_recursed(m))
 1262                         db_printf(" recursed: %d\n", m->mtx_recurse);
 1263         }
 1264 }
 1265 #endif

Cache object: 6cbeb41d004680dfd2840995c260da75


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.