/*
* Insert a rank that may be lower than the current rank in an
* appropriate position in the stack. This should only be used after a
* successful trylock of a lock with rank r.
*/
void insertRank(Rank r) {
assert(r != RankUnranked);
if (currentRank() <= r) {
pushRank(r);
return;
}
// Find the first real rank < r
int i;
for (i = tl_curRankDepth; i >= 0; i--) {
if (tl_rankStack[i] < r && tl_rankStack[i] != RankUnranked) {
break;
}
}
memmove(&tl_rankStack[i+1], &tl_rankStack[i],
sizeof(Rank) * (tl_curRankDepth - i));
tl_rankStack[i] = r;
}
// 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;
}
