1 /*
   2  * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package utils;
  24 
  25 import java.lang.management.ManagementFactory;
  26 import java.lang.management.MemoryPoolMXBean;
  27 import java.lang.management.MemoryUsage;
  28 import java.util.ArrayList;
  29 import java.util.List;
  30 
  31 /**
  32  *
  33  * Utilities to provoke GC in various ways
  34  */
  35 public class GcProvokerImpl implements GcProvoker {
  36 
  37     private static List<Object> eatenMetaspace;
  38     private static List<Object> eatenMemory;
  39 
  40     static List<Object> eatHeapMemory(float targetUsage) {
  41         long maxMemory = Runtime.getRuntime().maxMemory();
  42         // uses fixed small objects to avoid Humongous objects allocation in G1
  43         int memoryChunk = 2048;
  44         List<Object> list = new ArrayList<>();
  45         long used = 0;
  46         long target = (long) (maxMemory * targetUsage);
  47         while (used < target) {
  48             try {
  49                 list.add(new byte[memoryChunk]);
  50                 used += memoryChunk;
  51             } catch (OutOfMemoryError e) {
  52                 list = null;
  53                 throw new RuntimeException("Unexpected OOME '" + e.getMessage() + "' while eating " + targetUsage + " of heap memory.");
  54             }
  55         }
  56         return list;
  57     }
  58 
  59     @Override
  60     public void provokeGc() {
  61         for (int i = 0; i < 3; i++) {
  62             long edenSize = Pools.getEdenCommittedSize();
  63             long heapSize = Pools.getHeapCommittedSize();
  64             float targetPercent = ((float) edenSize) / (heapSize);
  65             if ((targetPercent < 0) || (targetPercent > 1.0)) {
  66                 throw new RuntimeException("Error in the percent calculation" + " (eden size: " + edenSize + ", heap size: " + heapSize + ", calculated eden percent: " + targetPercent + ")");
  67             }
  68             eatHeapMemory(targetPercent);
  69             eatHeapMemory(targetPercent);
  70             System.gc();
  71         }
  72     }
  73 
  74     @Override
  75     public void eatMetaspaceAndHeap(float targetMemoryUsagePercent) {
  76         // Metaspace should be filled before Java Heap to prevent unexpected OOME
  77         // in the Java Heap while filling Metaspace
  78         eatenMetaspace = eatMetaspace(targetMemoryUsagePercent);
  79         eatenMemory = eatHeapMemory(targetMemoryUsagePercent);
  80     }
  81 
  82     private static List<Object> eatMetaspace(float targetUsage) {
  83         List<Object> list = new ArrayList<>();
  84         final String metaspacePoolName = "Metaspace";
  85         MemoryPoolMXBean metaspacePool = null;
  86         for (MemoryPoolMXBean pool : ManagementFactory.getMemoryPoolMXBeans()) {
  87             if (pool.getName().contains(metaspacePoolName)) {
  88                 metaspacePool = pool;
  89                 break;
  90             }
  91         }
  92         if (metaspacePool == null) {
  93             throw new RuntimeException("MXBean for Metaspace pool wasn't found");
  94         }
  95         float currentUsage;
  96         GeneratedClassProducer gp = new GeneratedClassProducer();
  97         do {
  98             try {
  99                 list.add(gp.create(0));
 100             } catch (OutOfMemoryError oome) {
 101                 list = null;
 102                 throw new RuntimeException("Unexpected OOME '" + oome.getMessage() + "' while eating " + targetUsage + " of Metaspace.");
 103             }
 104             MemoryUsage memoryUsage = metaspacePool.getUsage();
 105             currentUsage = (((float) memoryUsage.getUsed()) / memoryUsage.getMax());
 106         } while (currentUsage < targetUsage);
 107         return list;
 108     }
 109 
 110     public GcProvokerImpl() {
 111     }
 112 
 113 }