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unlock if double lock succeeds but queues not empty

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This commit is contained in:
Stephen Birarda 2015-08-28 10:35:29 -07:00
parent ac3a1d54b1
commit 54cd430be9
1 changed files with 51 additions and 46 deletions
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97
libraries/networking/src/udt/SendQueue.cpp
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@ -347,60 +347,65 @@ void SendQueue::run() {
// To confirm that the queue of packets and the NAKs list are still both empty we'll need to use the DoubleLock
DoubleLock doubleLock(_packetsLock, _naksLock);
// The packets queue and loss list mutexes are now both locked - check if they're still both empty
if (doubleLock.try_lock() && _packets.empty() && _naks.getLength() == 0) {
if (doubleLock.try_lock()) {
// The packets queue and loss list mutexes are now both locked - check if they're still both empty
if (uint32_t(_lastACKSequenceNumber) == uint32_t(_currentSequenceNumber)) {
// we've sent the client as much data as we have (and they've ACKed it)
// either wait for new data to send or 5 seconds before cleaning up the queue
static const auto EMPTY_QUEUES_INACTIVE_TIMEOUT = std::chrono::seconds(5);
// use our condition_variable_any to wait
auto cvStatus = _emptyCondition.wait_for(doubleLock, EMPTY_QUEUES_INACTIVE_TIMEOUT);
// we have the double lock again - Make sure to unlock it
doubleLock.unlock();
if (cvStatus == std::cv_status::timeout) {
qDebug() << "SendQueue to" << _destination << "has been empty for"
if (_packets.empty() && _naks.getLength() == 0) {
if (uint32_t(_lastACKSequenceNumber) == uint32_t(_currentSequenceNumber)) {
// we've sent the client as much data as we have (and they've ACKed it)
// either wait for new data to send or 5 seconds before cleaning up the queue
static const auto EMPTY_QUEUES_INACTIVE_TIMEOUT = std::chrono::seconds(5);
// use our condition_variable_any to wait
auto cvStatus = _emptyCondition.wait_for(doubleLock, EMPTY_QUEUES_INACTIVE_TIMEOUT);
// we have the double lock again - Make sure to unlock it
doubleLock.unlock();
if (cvStatus == std::cv_status::timeout) {
qDebug() << "SendQueue to" << _destination << "has been empty for"
<< EMPTY_QUEUES_INACTIVE_TIMEOUT.count()
<< "seconds and receiver has ACKed all packets."
<< "The queue is considered inactive and will be stopped.";
// this queue is inactive - emit that signal and stop the while
emit queueInactive();
_isRunning = false;
return;
}
} else {
// We think the client is still waiting for data (based on the sequence number gap)
// Let's wait either for a response from the client or until the estimated timeout
auto waitDuration = std::chrono::microseconds(_estimatedTimeout);
// use our condition_variable_any to wait
auto cvStatus = _emptyCondition.wait_for(doubleLock, waitDuration);
if (cvStatus == std::cv_status::timeout) {
// increase the number of timeouts
++_timeoutExpiryCount;
if (SequenceNumber(_lastACKSequenceNumber) < _currentSequenceNumber) {
// after a timeout if we still have sent packets that the client hasn't ACKed we
// add them to the loss list
// Note that thanks to the DoubleLock we have the _naksLock right now
_naks.append(SequenceNumber(_lastACKSequenceNumber) + 1, _currentSequenceNumber);
// this queue is inactive - emit that signal and stop the while
emit queueInactive();
_isRunning = false;
return;
}
} else {
// We think the client is still waiting for data (based on the sequence number gap)
// Let's wait either for a response from the client or until the estimated timeout
auto waitDuration = std::chrono::microseconds(_estimatedTimeout);
// use our condition_variable_any to wait
auto cvStatus = _emptyCondition.wait_for(doubleLock, waitDuration);
if (cvStatus == std::cv_status::timeout) {
// increase the number of timeouts
++_timeoutExpiryCount;
if (SequenceNumber(_lastACKSequenceNumber) < _currentSequenceNumber) {
// after a timeout if we still have sent packets that the client hasn't ACKed we
// add them to the loss list
// Note that thanks to the DoubleLock we have the _naksLock right now
_naks.append(SequenceNumber(_lastACKSequenceNumber) + 1, _currentSequenceNumber);
}
}
// we have the double lock again - Make sure to unlock it
doubleLock.unlock();
// skip to the next iteration
continue;
}
// we have the double lock again - Make sure to unlock it
doubleLock.unlock();
// skip to the next iteration
continue;
}
// we got the try_lock but failed the other conditionals so we need to unlock
doubleLock.unlock();
}
}
}