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 }