HADOOP-6279. Add Runtime::maxMemory to JVM metrics. Contributed by Todd Lipcon

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@823271 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -15,6 +15,9 @@ Trunk (unreleased changes)
     HADOOP-6283. Improve the exception messages thrown by
     FileUtil$HardLink.getLinkCount(..).  (szetszwo)
 
+    HADOOP-6279. Add Runtime::maxMemory to JVM metrics. (Todd Lipcon via
+    cdouglas)
+
   OPTIMIZATIONS
 
   BUG FIXES

src/java/org/apache/hadoop/metrics/jvm/JvmMetrics.java

@@ -104,10 +104,13 @@ public class JvmMetrics implements Updater {
                 memoryMXBean.getNonHeapMemoryUsage();
         MemoryUsage memHeap =
                 memoryMXBean.getHeapMemoryUsage();
+        Runtime runtime = Runtime.getRuntime();
+
         metrics.setMetric("memNonHeapUsedM", memNonHeap.getUsed()/M);
         metrics.setMetric("memNonHeapCommittedM", memNonHeap.getCommitted()/M);
         metrics.setMetric("memHeapUsedM", memHeap.getUsed()/M);
         metrics.setMetric("memHeapCommittedM", memHeap.getCommitted()/M);
+        metrics.setMetric("maxMemoryM", runtime.maxMemory()/M);
     }
     
     private void doGarbageCollectionUpdates() {