//
// Tries to wakeup a waiting upgrader and/or all the waiting readers.
//
private bool TryWakeupUpgraderAndReaders() {
//
// Initialize the wakeup list and the released flag.
//
WaitNodeQueue wl = new WaitNodeQueue();
bool released = false;
//
// If the upgraders wait queue isn't empty, try to wakeup a
// waiting upgrader to enter the lock in upgradeable read mode.
//
if (!upQueue.IsEmpty) {
do {
WaitNode w = upQueue.Dequeue();
if (w.TryLock()) {
//
// Make the locked waiter as the current upgrader and
// add its wait node to the wake up list.
//
upgrader = w.tid;
wl.AddToWakeList(w);
released = true;
break;
}
} while (!upQueue.IsEmpty);
}
//
// Even when the r/w lock state changes to the upgrade read mode,
// all the waiting readers can enter the read lock.
//
while (!rdQueue.IsEmpty) {
WaitNode w = rdQueue.Dequeue();
if (w.TryLock()) {
//
// Account for one more active reader, add the respective
// entry to the reader owners table and add the waiting reader
// to the wake up list.
//
readers++;
rdCounts.Add(w.tid);
wl.AddToWakeList(w);
released = true;
}
}
//
// If no thread was released, return false holding the
// spinlock; otherwise, release the spinlock, unpark all
// threads inserted in the wake up list and return true.
//
if (!released) {
return false;
}
slock.Exit();
wl.UnparkAll();
return true;
}
//
// Tries to wakeup a waiting upgrader and/or all the waiting readers.
//
private bool TryWakeupUpgraderAndReaders()
{
//
// Initialize the wakeup list and the released flag.
//
WaitNodeQueue wl = new WaitNodeQueue();
bool released = false;
//
// If the upgraders wait queue isn't empty, try to wakeup a
// waiting upgrader to enter the lock in upgradeable read mode.
//
if (!upQueue.IsEmpty)
{
do
{
WaitNode w = upQueue.Dequeue();
if (w.TryLock())
{
//
// Make the locked waiter as the current upgrader and
// add its wait node to the wake up list.
//
upgrader = w.tid;
wl.AddToWakeList(w);
released = true;
break;
}
} while (!upQueue.IsEmpty);
}
//
// Even when the r/w lock state changes to the upgrade read mode,
// all the waiting readers can enter the read lock.
//
while (!rdQueue.IsEmpty)
{
WaitNode w = rdQueue.Dequeue();
if (w.TryLock())
{
//
// Account for one more active reader, add the respective
// entry to the reader owners table and add the waiting reader
// to the wake up list.
//
readers++;
rdCounts.Add(w.tid);
wl.AddToWakeList(w);
released = true;
}
}
//
// If no thread was released, return false holding the
// spinlock; otherwise, release the spinlock, unpark all
// threads inserted in the wake up list and return true.
//
if (!released)
{
return(false);
}
slock.Exit();
wl.UnparkAll();
return(true);
}
