test/serviceability/tmtools/jstat/utils/GcProvoker.java

rev 12309 : Rev 01

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.

@@ -20,36 +20,138 @@
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */
 package utils;
 
+import java.lang.management.ManagementFactory;
+import java.lang.management.MemoryPoolMXBean;
+import java.lang.management.MemoryUsage;
+import java.util.ArrayList;
+import java.util.List;
+
 /**
- * This is an interface used to provoke GC and perform other GC-related
+ * This is an class used to provoke GC and perform other GC-related
  * procedures
  *
  */
-public interface GcProvoker {
+public class GcProvoker{
+
+    // Uses fixed small objects to avoid Humongous objects allocation in G1
+    public static final int MEMORY_CHUNK = 2048;
+    public static final float ALLOCATION_TOLERANCE = 0.05f;
+
+    public static List<Object> allocatedMetaspace;
+    public static List<Object> allocatedMemory;
+    
+    private final Runtime runtime;
+
+    private List<Object> allocateHeap(float targetUsage) {
+        long maxMemory = runtime.maxMemory();
+        List<Object> list = new ArrayList<>();
+        long used = 0;
+        long target = (long) (maxMemory * targetUsage);
+        while (used < target) {
+            try {
+                list.add(new byte[MEMORY_CHUNK]);
+                used += MEMORY_CHUNK;
+            } catch (OutOfMemoryError e) {
+                list = null;
+                throw new RuntimeException("Unexpected OOME '" + e.getMessage() + "' while eating " + targetUsage + " of heap memory.");
+            }
+        }
+        return list;
+    }
+    
+    private List<Object> allocateAvailableHeap(float targetUsage) {
+        // Calculates size of free memory after allocation with small tolerance.
+        long minFreeMemory = (long) ((1.0 - (targetUsage + ALLOCATION_TOLERANCE)) * runtime.maxMemory());
+        List<Object> list = new ArrayList<>();
+        do {
+            try {
+                list.add(new byte[MEMORY_CHUNK]);
+            } catch (OutOfMemoryError e) {
+                list = null;
+                throw new RuntimeException("Unexpected OOME '" + e.getMessage() + "' while eating " + targetUsage + " of heap memory.");
+            }
+        } while (runtime.freeMemory() > minFreeMemory);
+        return list;
+    }
 
     /**
-     * The default implementation
-     *
-     * @return the default GC provoker
+     * This method provokes a GC
      */
-    public static GcProvoker createGcProvoker() {
-        return new GcProvokerImpl();
+    public void provokeGc() {
+        for (int i = 0; i < 3; i++) {
+            long edenSize = Pools.getEdenCommittedSize();
+            long heapSize = Pools.getHeapCommittedSize();
+            float targetPercent = ((float) edenSize) / (heapSize);
+            if ((targetPercent < 0) || (targetPercent > 1.0)) {
+                throw new RuntimeException("Error in the percent calculation" + " (eden size: " + edenSize + ", heap size: " + heapSize + ", calculated eden percent: " + targetPercent + ")");
+            }
+            allocateHeap(targetPercent);
+            allocateHeap(targetPercent);
+            System.gc();
+        }
     }
 
     /**
-     * This method provokes a GC
+     * Allocates heap and metaspace upon exit not less than targetMemoryUsagePercent percents 
+     * of heap and metaspace have been consumed.
+     *
+     * @param targetMemoryUsagePercent how many percent of heap and metaspace to
+     * allocate
      */
-    public void provokeGc();
+
+    public void allocateMetaspaceAndHeap(float targetMemoryUsagePercent) {
+        // Metaspace should be filled before Java Heap to prevent unexpected OOME
+        // in the Java Heap while filling Metaspace
+        allocatedMetaspace = eatMetaspace(targetMemoryUsagePercent);
+        allocatedMemory = allocateHeap(targetMemoryUsagePercent);
+    }
 
     /**
-     * Eats heap and metaspace Upon exit targetMemoryUsagePercent percents of
-     * heap and metaspace is have been eaten
+     * Allocates heap and metaspace upon exit targetMemoryUsagePercent percents 
+     * of heap and metaspace have been consumed.
      *
      * @param targetMemoryUsagePercent how many percent of heap and metaspace to
-     * eat
+     * allocate
      */
-    public void eatMetaspaceAndHeap(float targetMemoryUsagePercent);
+    public void allocateAvailableMetaspaceAndHeap(float targetMemoryUsagePercent) {
+        // Metaspace should be filled before Java Heap to prevent unexpected OOME
+        // in the Java Heap while filling Metaspace
+        allocatedMetaspace = eatMetaspace(targetMemoryUsagePercent);
+        allocatedMemory = allocateAvailableHeap(targetMemoryUsagePercent);
+    }
+
+    private List<Object> eatMetaspace(float targetUsage) {
+        List<Object> list = new ArrayList<>();
+        final String metaspacePoolName = "Metaspace";
+        MemoryPoolMXBean metaspacePool = null;
+        for (MemoryPoolMXBean pool : ManagementFactory.getMemoryPoolMXBeans()) {
+            if (pool.getName().contains(metaspacePoolName)) {
+                metaspacePool = pool;
+                break;
+            }
+        }
+        if (metaspacePool == null) {
+            throw new RuntimeException("MXBean for Metaspace pool wasn't found");
+        }
+        float currentUsage;
+        GeneratedClassProducer gp = new GeneratedClassProducer();
+        do {
+            try {
+                list.add(gp.create(0));
+            } catch (OutOfMemoryError oome) {
+                list = null;
+                throw new RuntimeException("Unexpected OOME '" + oome.getMessage() + "' while eating " + targetUsage + " of Metaspace.");
+            }
+            MemoryUsage memoryUsage = metaspacePool.getUsage();
+            currentUsage = (((float) memoryUsage.getUsed()) / memoryUsage.getMax());
+        } while (currentUsage < targetUsage);
+        return list;
+    }
+
+    public GcProvoker() {
+        runtime = Runtime.getRuntime();
+    }
 
 }