private Severity getMemoryRatioSeverity(double ratio) {
    return Severity.getSeverityDescending(
            ratio, memoryRatioLimits[0], memoryRatioLimits[1], memoryRatioLimits[2], memoryRatioLimits[3]);
  }
Analyzes mapper memory allocation and requirements
app/com/linkedin/drelephant/tez/heuristics/GenericMemoryHeuristic.java