private Severity getContainerMemorySeverity(long taskMemMax) {
    return Severity.getSeverityAscending(
        taskMemMax, memoryLimits[0], memoryLimits[1], memoryLimits[2], memoryLimits[3]);
  }
This heuristic deals with the efficiency of container size
app/com/linkedin/drelephant/mapreduce/heuristics/GenericMemoryHeuristic.java