Lease::~Lease() {
if (amOwner()) {
// Can happen, e.g., in exception scenarios.
pthread_mutex_unlock(&m_lock);
}
pthread_mutex_destroy(&m_lock);
}
void Lease::gremlinLock() {
if (amOwner()) {
TRACE(2, "Lease: gremlinLock dropping lease\n");
drop();
}
pthread_mutex_lock(&m_lock);
TRACE(2, "Lease: gremlin grabbed lock\n ");
m_held = true;
m_owner = gremlinize_threadid(pthread_self());
}
void Lease::drop(int64_t hintExpireDelay) {
assertx(amOwner());
TRACE(4, "thr%" PRIx64 ": dropping lease, called by %p,%p\n",
Process::GetThreadIdForTrace(), __builtin_return_address(0),
__builtin_return_address(1));
if (debug) {
popRank(RankWriteLease);
}
m_hintExpire = hintExpireDelay > 0 ?
Timer::GetCurrentTimeMicros() + hintExpireDelay : 0;
m_held.store(false, std::memory_order_release);
pthread_mutex_unlock(&m_lock);
}
void Lease::drop(int64 hintExpireDelay) {
assert(amOwner());
TRACE(4, "thr%lx: dropping lease, called by %p,%p\n",
pthread_self(), __builtin_return_address(0),
__builtin_return_address(1));
if (debug) {
popRank(RankWriteLease);
Translator::Get()->protectCode();
}
m_hintExpire = hintExpireDelay > 0 ?
Timer::GetCurrentTimeMicros() + hintExpireDelay : 0;
m_held = false;
pthread_mutex_unlock(&m_lock);
}
// acquire: also returns true if we are already the writer.
bool Lease::acquire(bool blocking /* = false */ ) {
if (amOwner()) {
return true;
}
if (!threadCanAcquire && !blocking) {
return false;
}
int64_t expire = m_hintExpire;
int64_t expireDiff = expire - Timer::GetCurrentTimeMicros();
if (!blocking && (m_held.load(std::memory_order_acquire) ||
(expireDiff > 0 && m_owner != pthread_self()))) {
return false;
}
checkRank(RankWriteLease);
auto const locked = blocking ? pthread_mutex_lock(&m_lock)
: pthread_mutex_trylock(&m_lock);
if (locked == 0) {
TRACE(4, "thr%" PRIx64 ": acquired lease, called by %p,%p\n",
Process::GetThreadIdForTrace(), __builtin_return_address(0),
__builtin_return_address(1));
if (debug) {
pushRank(RankWriteLease);
if (expire != 0 && m_owner != pthread_self()) {
m_hintGrabbed++;
TRACE(3,
"thr%" PRIx64 ": acquired hinted lease"
", expired %" PRId64 "us ago\n",
Process::GetThreadIdForTrace(), -expireDiff);
} else if (expire != 0 && m_owner == pthread_self()) {
m_hintKept++;
}
}
m_owner = pthread_self();
m_hintExpire = 0;
m_held.store(true, std::memory_order_release);
return true;
}
always_assert(!blocking && "Failed to acquire write lease in blocking mode");
return false;
}
// acquire: also returns true if we are already the writer.
bool Lease::acquire(bool blocking /* = false */ ) {
if (amOwner()) {
return true;
}
int64_t expire = m_hintExpire;
int64_t expireDiff = expire - Timer::GetCurrentTimeMicros();
if (!blocking && (m_held ||
(expireDiff > 0 && m_owner != pthread_self()))) {
return false;
}
checkRank(RankWriteLease);
if (0 == (blocking ?
pthread_mutex_lock(&m_lock) :
pthread_mutex_trylock(&m_lock))) {
TRACE(4, "thr%" PRIx64 ": acquired lease, called by %p,%p\n",
Process::GetThreadIdForTrace(), __builtin_return_address(0),
__builtin_return_address(1));
if (debug) {
pushRank(RankWriteLease);
if (expire != 0 && m_owner != pthread_self()) {
m_hintGrabbed++;
TRACE(3,
"thr%" PRIx64 ": acquired hinted lease"
", expired %" PRId64 "us ago\n",
Process::GetThreadIdForTrace(), -expireDiff);
} else if (expire != 0 && m_owner == pthread_self()) {
m_hintKept++;
}
tx64->unprotectCode();
}
m_owner = pthread_self();
m_hintExpire = 0;
m_held = true;
return true;
}
if (blocking) {
TRACE(3, "thr%" PRIx64 ": failed to acquired lease in blocking mode\n",
Process::GetThreadIdForTrace());
}
return false;
}
