SharedPtr<Thread> AddressArbiter::ResumeHighestPriorityThread(VAddr address) {
// Determine which threads are waiting on this address, those should be considered for wakeup.
auto matches_start = std::stable_partition(
waiting_threads.begin(), waiting_threads.end(), [address](const auto& thread) {
ASSERT_MSG(thread->status == ThreadStatus::WaitArb,
"Inconsistent AddressArbiter state");
return thread->wait_address != address;
});
// Iterate through threads, find highest priority thread that is waiting to be arbitrated.
// Note: The real kernel will pick the first thread in the list if more than one have the
// same highest priority value. Lower priority values mean higher priority.
auto itr = std::min_element(matches_start, waiting_threads.end(),
[](const auto& lhs, const auto& rhs) {
return lhs->current_priority < rhs->current_priority;
});
if (itr == waiting_threads.end())
return nullptr;
auto thread = *itr;
thread->ResumeFromWait();
waiting_threads.erase(itr);
return thread;
}
void Thread::ReleaseWaitObject(WaitObject* wait_object) {
if (status != THREADSTATUS_WAIT_SYNCH || wait_objects.empty()) {
LOG_CRITICAL(Kernel, "thread is not waiting on any objects!");
return;
}
// Remove this thread from the waiting object's thread list
wait_object->RemoveWaitingThread(this);
unsigned index = 0;
bool wait_all_failed = false; // Will be set to true if any object is unavailable
// Iterate through all waiting objects to check availability...
for (auto itr = wait_objects.begin(); itr != wait_objects.end(); ++itr) {
if ((*itr)->ShouldWait())
wait_all_failed = true;
// The output should be the last index of wait_object
if (*itr == wait_object)
index = itr - wait_objects.begin();
}
// If we are waiting on all objects...
if (wait_all) {
// Resume the thread only if all are available...
if (!wait_all_failed) {
SetWaitSynchronizationResult(RESULT_SUCCESS);
SetWaitSynchronizationOutput(-1);
ResumeFromWait();
}
} else {
// Otherwise, resume
SetWaitSynchronizationResult(RESULT_SUCCESS);
if (wait_set_output)
SetWaitSynchronizationOutput(index);
ResumeFromWait();
}
}