void
mutex_destroy(kmutex_t *mp)
{
mutex_impl_t *lp = (mutex_impl_t *)mp;
if (lp->m_owner == 0 && !MUTEX_HAS_WAITERS(lp)) {
MUTEX_DESTROY(lp);
} else if (MUTEX_TYPE_SPIN(lp)) {
LOCKSTAT_RECORD0(LS_MUTEX_DESTROY_RELEASE, lp);
MUTEX_DESTROY(lp);
} else if (MUTEX_TYPE_ADAPTIVE(lp)) {
LOCKSTAT_RECORD0(LS_MUTEX_DESTROY_RELEASE, lp);
if (MUTEX_OWNER(lp) != curthread)
mutex_panic("mutex_destroy: not owner", lp);
if (MUTEX_HAS_WAITERS(lp)) {
turnstile_t *ts = turnstile_lookup(lp);
turnstile_exit(lp);
if (ts != NULL)
mutex_panic("mutex_destroy: has waiters", lp);
}
MUTEX_DESTROY(lp);
} else {
mutex_panic("mutex_destroy: bad mutex", lp);
}
}
/** \brief Release the acquired mutex
*
* \b os_mutexUnlock calls \b pthread_mutex_unlock to release
* the posix \b mutex.
*/
void os_mutexUnlock (os_mutex *mutex)
{
assert (mutex != NULL);
#ifdef OSPL_STRICT_MEM
assert (mutex->signature == OS_MUTEX_MAGIC_SIG);
#endif
if (mutex->name[0] != '\0') {
STATUS status;
SEM_ID id;
#if 1
/* NB: id lookup in cache is for debugging reasons */
id = get_mutex (mutex);
#else
id = pa_ldvoidp (&mutex->info.id);
#endif
cas_mutex_info_id (mutex, id, 0);
status = semGive (id);
if (status != OK) {
mutex_panic("unlock: semGive failed", status);
}
} else {
int res = pthread_mutex_unlock (&mutex->info.posix_mutex);
if (res != 0) {
mutex_panic ("unlock: semGive failed", res);
}
}
}
static SEM_ID get_mutex (os_mutex *mutex)
{
SEM_ID result;
int options;
semTake (cache_lock, WAIT_FOREVER);
result = (SEM_ID) ut_get (cache, mutex);
if (!result)
{
/* In single process mode only "private" variables are required */
options = (SEM_Q_PRIORITY | SEM_DELETE_SAFE);
/* Set option for priority inheritance if feature is enabled */
if (ospl_mtx_prio_inherit) {
options = options | SEM_INVERSION_SAFE;
}
result = semOpen(mutex->name, SEM_TYPE_MUTEX, SEM_EMPTY, options, 0, NULL);
if (result) {
(void) ut_tableInsert ((ut_table) cache, mutex, result);
} else {
mutex_panic ("get_mutex", 0);
}
}
semGive (cache_lock);
return result;
}
/** \brief Destroy the mutex
*
* \b os_mutexDestroy calls \b pthread_mutex_destroy to destroy the
* posix \b mutex.
*/
void os_mutexDestroy (os_mutex *mutex)
{
assert (mutex != NULL);
#ifdef OSPL_STRICT_MEM
assert (mutex->signature == OS_MUTEX_MAGIC_SIG);
#endif
if (mutex->name[0] != '\0') {
SEM_ID id;
/* shared mutex */
id = ut_get (cache, mutex);
cas_mutex_info_id (mutex, 0, invalid_sem_id);
if (id) {
semClose (id);
semTake(cache_lock, WAIT_FOREVER);
ut_remove (cache, mutex);
semGive(cache_lock);
}
} else {
int res = pthread_mutex_destroy (&mutex->info.posix_mutex);
if (res != 0) {
mutex_panic ("pthread_mutex_destroy failed", res);
}
}
#ifdef OSPL_STRICT_MEM
mutex->signature = 0;
#endif
}
os_result os_mutexInit (os_mutex *mutex, const os_mutexAttr *mutexAttr)
{
os_mutexAttr defAttr;
os_result rv;
int options;
SEM_ID id;
assert (mutex != NULL);
#ifdef OSPL_STRICT_MEM
assert (mutex->signature != OS_MUTEX_MAGIC_SIG);
#endif
if(!mutexAttr) {
os_mutexAttrInit(&defAttr);
mutexAttr = &defAttr;
}
options = (SEM_Q_PRIORITY | SEM_DELETE_SAFE);
/* Set option for priority inheritance if feature is enabled */
if (ospl_mtx_prio_inherit) {
options = options | SEM_INVERSION_SAFE;
}
if (mutexAttr->scopeAttr == OS_SCOPE_SHARED) {
/* create named mutex using shared address as unique name */
snprintf (mutex->name, sizeof (mutex->name), "/%lu", (os_uint32) mutex);
id = semOpen (mutex->name, SEM_TYPE_MUTEX, SEM_EMPTY, options, OM_CREATE|OM_EXCL, NULL);
/* As it may exist from a previous run. remove leftover semaphore object */
if (id != NULL) {
/* a fresh one, initialise it and cache the SEM_ID */
pa_st32 ((void *) &mutex->info.id, 0);
semTake (cache_lock, WAIT_FOREVER);
(void) ut_tableInsert ((ut_table) cache, mutex, id);
semGive (cache_lock);
} else {
/* re-using an old one: it should have been destroyed and hence should have a marker in info.id */
id = get_mutex (mutex);
if (id != NULL) {
semTake (id, WAIT_FOREVER);
semGive (id);
/*cas_mutex_info_id ((void*)&mutex->info.id, invalid_sem_id, 0);*/
} else {
mutex_panic ("init: attempt to reuse semaphore currently in use", 0);
}
}
rv = (id != NULL) ? os_resultSuccess : os_resultFail;
} else {
int result;
mutex->name[0] = '\0';
/* TODO attrs */
result = pthread_mutex_init(&mutex->info.posix_mutex, NULL);
rv = (result == 0) ? os_resultSuccess : os_resultFail;
}
#ifdef OSPL_STRICT_MEM
mutex->signature = OS_MUTEX_MAGIC_SIG;
#endif
return rv;
}
static void cas_mutex_info_id (os_mutex *mutex, SEM_ID expected, SEM_ID id)
{
SEM_ID cached_id;
do {
cached_id = pa_ldvoidp ((void*) &mutex->info.id);
if (cached_id != expected) {
mutex_panic ("sem id mismatch in cas_mutex_info_id", 0);
}
} while (!pa_casvoidp ((void*) &mutex->info.id, expected, id));
}
/** \brief Try to acquire the mutex, immediately return if the mutex
* is already acquired by another thread
*
* \b os_mutexTryLock calls \b pthread_mutex_trylock to acquire
* the posix \b mutex.
*/
os_result os_mutexTryLock (os_mutex *mutex)
{
os_result rv = os_resultFail;
assert (mutex != NULL);
#ifdef OSPL_STRICT_MEM
assert (mutex->signature == OS_MUTEX_MAGIC_SIG);
#endif
if (mutex->name[0] != '\0') {
STATUS result;
SEM_ID id;
id = get_mutex (mutex);
result = semTake(id, NO_WAIT);
if (result == OK) {
cas_mutex_info_id (mutex, 0, id);
rv = os_resultSuccess;
} else {
if (os_getErrno() == S_objLib_OBJ_UNAVAILABLE) {
rv = os_resultBusy;
} else {
mutex_panic ("trylock: semTake failed", result);
}
}
} else {
int res = pthread_mutex_trylock (&mutex->info.posix_mutex);
if (res == 0) {
rv = os_resultSuccess;
} else if (res == EBUSY) {
rv = os_resultBusy;
} else {
mutex_panic ("pthread_mutex_trylock failed", res);
}
}
return rv;
}
/*
* mutex_vector_tryenter() is called from the assembly mutex_tryenter()
* routine if the lock is held or is not of type MUTEX_ADAPTIVE.
*/
int
mutex_vector_tryenter(mutex_impl_t *lp)
{
int s;
if (MUTEX_TYPE_ADAPTIVE(lp))
return (0); /* we already tried in assembly */
if (!MUTEX_TYPE_SPIN(lp)) {
mutex_panic("mutex_tryenter: bad mutex", lp);
return (0);
}
s = splr(lp->m_spin.m_minspl);
if (lock_try(&lp->m_spin.m_spinlock)) {
lp->m_spin.m_oldspl = (ushort_t)s;
return (1);
}
splx(s);
return (0);
}
/*
* mutex_vector_exit() is called from mutex_exit() if the lock is not
* adaptive, has waiters, or is not owned by the current thread (panic).
*/
void
mutex_vector_exit(mutex_impl_t *lp)
{
turnstile_t *ts;
if (MUTEX_TYPE_SPIN(lp)) {
lock_clear_splx(&lp->m_spin.m_spinlock, lp->m_spin.m_oldspl);
return;
}
if (MUTEX_OWNER(lp) != curthread) {
mutex_panic("mutex_exit: not owner", lp);
return;
}
ts = turnstile_lookup(lp);
MUTEX_CLEAR_LOCK_AND_WAITERS(lp);
if (ts == NULL)
turnstile_exit(lp);
else
turnstile_wakeup(ts, TS_WRITER_Q, ts->ts_waiters, NULL);
LOCKSTAT_RECORD0(LS_MUTEX_EXIT_RELEASE, lp);
}
void os_mutexLock (os_mutex *mutex)
{
if (os_mutexLock_s (mutex) != os_resultSuccess) {
mutex_panic ("mutexLock failed", 0);
}
}
/*
* mutex_vector_enter() is called from the assembly mutex_enter() routine
* if the lock is held or is not of type MUTEX_ADAPTIVE.
*/
void
mutex_vector_enter(mutex_impl_t *lp)
{
kthread_id_t owner;
hrtime_t sleep_time = 0; /* how long we slept */
uint_t spin_count = 0; /* how many times we spun */
cpu_t *cpup, *last_cpu;
extern cpu_t *cpu_list;
turnstile_t *ts;
volatile mutex_impl_t *vlp = (volatile mutex_impl_t *)lp;
int backoff; /* current backoff */
int backctr; /* ctr for backoff */
int sleep_count = 0;
ASSERT_STACK_ALIGNED();
if (MUTEX_TYPE_SPIN(lp)) {
lock_set_spl(&lp->m_spin.m_spinlock, lp->m_spin.m_minspl,
&lp->m_spin.m_oldspl);
return;
}
if (!MUTEX_TYPE_ADAPTIVE(lp)) {
mutex_panic("mutex_enter: bad mutex", lp);
return;
}
/*
* Adaptive mutexes must not be acquired from above LOCK_LEVEL.
* We can migrate after loading CPU but before checking CPU_ON_INTR,
* so we must verify by disabling preemption and loading CPU again.
*/
cpup = CPU;
if (CPU_ON_INTR(cpup) && !panicstr) {
kpreempt_disable();
if (CPU_ON_INTR(CPU))
mutex_panic("mutex_enter: adaptive at high PIL", lp);
kpreempt_enable();
}
CPU_STATS_ADDQ(cpup, sys, mutex_adenters, 1);
if (&plat_lock_delay) {
backoff = 0;
} else {
backoff = BACKOFF_BASE;
}
for (;;) {
spin:
spin_count++;
/*
* Add an exponential backoff delay before trying again
* to touch the mutex data structure.
* the spin_count test and call to nulldev are to prevent
* the compiler optimizer from eliminating the delay loop.
*/
if (&plat_lock_delay) {
plat_lock_delay(&backoff);
} else {
for (backctr = backoff; backctr; backctr--) {
if (!spin_count) (void) nulldev();
}; /* delay */
backoff = backoff << 1; /* double it */
if (backoff > BACKOFF_CAP) {
backoff = BACKOFF_CAP;
}
SMT_PAUSE();
}
if (panicstr)
return;
if ((owner = MUTEX_OWNER(vlp)) == NULL) {
if (mutex_adaptive_tryenter(lp))
break;
continue;
}
if (owner == curthread)
mutex_panic("recursive mutex_enter", lp);
/*
* If lock is held but owner is not yet set, spin.
* (Only relevant for platforms that don't have cas.)
*/
if (owner == MUTEX_NO_OWNER)
continue;
/*
* When searching the other CPUs, start with the one where
* we last saw the owner thread. If owner is running, spin.
*
* We must disable preemption at this point to guarantee
* that the list doesn't change while we traverse it
* without the cpu_lock mutex. While preemption is
* disabled, we must revalidate our cached cpu pointer.
*/
kpreempt_disable();
if (cpup->cpu_next == NULL)
cpup = cpu_list;
last_cpu = cpup; /* mark end of search */
do {
if (cpup->cpu_thread == owner) {
kpreempt_enable();
goto spin;
}
} while ((cpup = cpup->cpu_next) != last_cpu);
kpreempt_enable();
/*
* The owner appears not to be running, so block.
* See the Big Theory Statement for memory ordering issues.
*/
ts = turnstile_lookup(lp);
MUTEX_SET_WAITERS(lp);
membar_enter();
/*
* Recheck whether owner is running after waiters bit hits
* global visibility (above). If owner is running, spin.
*
* Since we are at ipl DISP_LEVEL, kernel preemption is
* disabled, however we still need to revalidate our cached
* cpu pointer to make sure the cpu hasn't been deleted.
*/
if (cpup->cpu_next == NULL)
last_cpu = cpup = cpu_list;
do {
if (cpup->cpu_thread == owner) {
turnstile_exit(lp);
goto spin;
}
} while ((cpup = cpup->cpu_next) != last_cpu);
membar_consumer();
/*
* If owner and waiters bit are unchanged, block.
*/
if (MUTEX_OWNER(vlp) == owner && MUTEX_HAS_WAITERS(vlp)) {
sleep_time -= gethrtime();
(void) turnstile_block(ts, TS_WRITER_Q, lp,
&mutex_sobj_ops, NULL, NULL);
sleep_time += gethrtime();
sleep_count++;
} else {
turnstile_exit(lp);
}
}
ASSERT(MUTEX_OWNER(lp) == curthread);
if (sleep_time != 0) {
/*
* Note, sleep time is the sum of all the sleeping we
* did.
*/
LOCKSTAT_RECORD(LS_MUTEX_ENTER_BLOCK, lp, sleep_time);
}
/*
* We do not count a sleep as a spin.
*/
if (spin_count > sleep_count)
LOCKSTAT_RECORD(LS_MUTEX_ENTER_SPIN, lp,
spin_count - sleep_count);
LOCKSTAT_RECORD0(LS_MUTEX_ENTER_ACQUIRE, lp);
}
