public boolean shouldKickNewTaskOnHost(long timeOnQueue, HostState host) {
synchronized (hostAvailSlots) {
if (hostAvailSlots.containsKey(host.getHostUuid())
&& hostAvailSlots.get(host.getHostUuid()) <= 1) {
if (host.getMaxTaskSlots() == 1) {
// If a host has only one slot to begin with, allow tasks to kick there.
return true;
}
// Otherwise, don't let new tasks take the last slot for a set period
return timeOnQueue > SPAWN_QUEUE_NEW_TASK_LAST_SLOT_DELAY;
}
return true;
}
}
/**
* Out of a list of possible hosts to run a task, find the best one.
*
* @param inputHosts The legal hosts for a task
* @param requireAvailableSlot Whether to require at least one available slot
* @return One of the hosts, if one with free slots is found; null otherwise
*/
public HostState findBestHostToRunTask(List<HostState> inputHosts, boolean requireAvailableSlot) {
if (inputHosts == null || inputHosts.isEmpty()) {
return null;
}
synchronized (hostAvailSlots) {
HostState bestHost = Collections.min(inputHosts, hostStateComparator);
if (bestHost != null) {
if (!requireAvailableSlot
|| hostAvailSlots.containsKey(bestHost.getHostUuid())
&& hostAvailSlots.get(bestHost.getHostUuid()) > 0) {
return bestHost;
}
}
return null;
}
}
/**
* Update the available slots for each host if it has been sufficiently long since the last
* update.
*
* @param hosts The hosts to input
*/
public void updateAllHostAvailSlots(List<HostState> hosts) {
synchronized (hostAvailSlots) {
if (JitterClock.globalTime() - lastAvailSlotsUpdate < SPAWN_QUEUE_AVAIL_REFRESH) {
return;
}
hostAvailSlots.clear();
for (HostState host : hosts) {
String hostID = host.getHostUuid();
if (hostID != null) {
hostAvailSlots.put(hostID, host.getAvailableTaskSlots());
}
}
}
lastAvailSlotsUpdate = JitterClock.globalTime();
if (log.isTraceEnabled()) {
log.trace("[SpawnQueuesByPriority] Host Avail Slots: " + hostAvailSlots);
}
}
@Override
public int compare(HostState o1, HostState o2) {
int hostAvailSlots1 =
hostAvailSlots.containsKey(o1.getHostUuid())
? hostAvailSlots.get(o1.getHostUuid())
: 0;
int hostAvailSlots2 =
hostAvailSlots.containsKey(o2.getHostUuid())
? hostAvailSlots.get(o2.getHostUuid())
: 0;
if (hostAvailSlots1 != hostAvailSlots2) {
return Integer.compare(
-hostAvailSlots1,
-hostAvailSlots2); // Return hosts with large number of slots first
} else {
return Double.compare(
o1.getMeanActiveTasks(),
o2.getMeanActiveTasks()); // Return hosts with small meanActiveTask value first
}
}