1 /*

     2  * Copyright (c) 2015, 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         float used = 0;

    46         while (used < targetUsage * maxMemory) {

    47             try {

    48                 list.add(new byte[memoryChunk]);

    49                 used += memoryChunk;

    50             } catch (OutOfMemoryError e) {

    51                 list = null;

    52                 throw new RuntimeException("Unexpected OOME while eating " + targetUsage + " of heap memory.");

    53             }

    54         }

    55         return list;

    56     }

    57 

    58     @Override

    59     public void provokeGc() {

    60         for (int i = 0; i < 3; i++) {

    61             long edenSize = Pools.getEdenCommittedSize();

    62             long heapSize = Pools.getHeapCommittedSize();

    63             float targetPercent = ((float) edenSize) / (heapSize);

    64             if ((targetPercent <= 0) || (targetPercent > 1.0)) {

    65                 throw new RuntimeException("Error in the percent calculation" + " (eden size: " + edenSize + ", heap size: " + heapSize + ", calculated eden percent: " + targetPercent + ")");

    66             }

    67             eatHeapMemory(targetPercent);

    68             eatHeapMemory(targetPercent);

    69             System.gc();

    70         }

    71     }

    72 

    73     @Override

    74     public void eatMetaspaceAndHeap(float targetMemoryUsagePercent) {

    75         eatenMemory = eatHeapMemory(targetMemoryUsagePercent);

    76         eatenMetaspace = eatMetaspace(targetMemoryUsagePercent);

    77     }

    78 

    79     private static List<Object> eatMetaspace(float targetUsage) {

    80         List<Object> list = new ArrayList<>();

    81         final String metaspacePoolName = "Metaspace";

    82         MemoryPoolMXBean metaspacePool = null;

    83         for (MemoryPoolMXBean pool : ManagementFactory.getMemoryPoolMXBeans()) {

    84             if (pool.getName().contains(metaspacePoolName)) {

    85                 metaspacePool = pool;

    86                 break;

    87             }

    88         }

    89         if (metaspacePool == null) {

    90             throw new RuntimeException("MXBean for Metaspace pool wasn't found");

    91         }

    92         float currentUsage;

    93         GeneratedClassProducer gp = new GeneratedClassProducer();

    94         do {

    95             try {

    96                 list.add(gp.create(0));

    97             } catch (OutOfMemoryError oome) {

    98                 list = null;

    99                 throw new RuntimeException("Unexpected OOME while eating " + targetUsage + " of Metaspace.");

   100             }

   101             MemoryUsage memoryUsage = metaspacePool.getUsage();

   102             currentUsage = (((float) memoryUsage.getUsed()) / memoryUsage.getMax());

   103         } while (currentUsage < targetUsage);

   104         return list;

   105     }

   106 

   107     public GcProvokerImpl() {

   108     }

   109 

   110 }