public void registerTaskRequest(String[] requestedHosts, String[] requestedRacks) {
    numRequestedAllocations.incrementAndGet();
    // TODO Change after HIVE-9987. For now, there's no rack matching.
    if (requestedHosts != null && requestedHosts.length != 0) {
      numRequestsWithLocation.incrementAndGet();
    } else {
      numRequestsWithoutLocation.incrementAndGet();
    }
  }
Update DAG metrics caused by an incoming allocate Task call.
Updated metrics should use Atomics here to avoid using a lock on the caller.
@param requestedHosts
@param requestedRacks
llap-tez/src/java/org/apache/hadoop/hive/llap/tezplugins/scheduler/StatsPerDag.java