Method GetNextHiPriTask

source/task_scheduler.cpp:512–579

}

bool TaskScheduler::GetNextHiPriTask(TaskBundle *nextTask, std::vector<TaskBundle> *taskBuffer) {
	unsigned const currentThreadIndex = GetCurrentThreadIndex();
	ThreadLocalStorage &tls = m_tls[currentThreadIndex];

	bool result = false;

	// Try to pop from our own queue
	while (tls.HiPriTaskQueue.Pop(nextTask)) {
		if (TaskIsReadyToExecute(nextTask)) {
			result = true;
			// Break to cleanup
			goto cleanup; // NOLINT(cppcoreguidelines-avoid-goto)
		}

		// It's a ReadyTask whose fiber hasn't switched away yet
		// Add it to the buffer
		taskBuffer->emplace_back(*nextTask);
	}

	// Force a scope so the `goto cleanup` above doesn't skip initialization
	{
		// Ours is empty, try to steal from the others'
		const unsigned threadIndex = tls.HiPriLastSuccessfulSteal;
		for (unsigned i = 0; i < m_numThreads; ++i) {
			const unsigned threadIndexToStealFrom = (threadIndex + i) % m_numThreads;
			if (threadIndexToStealFrom == currentThreadIndex) {
				continue;
			}
			ThreadLocalStorage &otherTLS = m_tls[threadIndexToStealFrom];

			while (otherTLS.HiPriTaskQueue.Steal(nextTask)) {
				tls.HiPriLastSuccessfulSteal = threadIndexToStealFrom;

				if (TaskIsReadyToExecute(nextTask)) {
					result = true;
					// Break to cleanup
					goto cleanup;
				}

				// It's a ReadyTask whose fiber hasn't switched away yet
				// Add it to the buffer
				taskBuffer->emplace_back(*nextTask);
			}
		}
	}

cleanup:
	if (!taskBuffer->empty()) {
		// Re-push all the tasks we found that we're ready to execute
		// We (or another thread) will get them next round
		do {
			// Push them in the opposite order we popped them, to restore the order
			tls.HiPriTaskQueue.Push(taskBuffer->back());
			taskBuffer->pop_back();
		} while (!taskBuffer->empty());

		// If we're using Sleep mode, we need to wake up the other threads
		// They may have looked for tasks while we had them all in our temp buffer and thus not