1 /*

     2  * Copyright (c) 2012, 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 

    24 /*

    25  * @test Humongous.java

    26  * @bug 7168848

    27  * @summary G1: humongous object allocations should initiate marking cycles when necessary

    28  * @run main/othervm -Xms100m -Xmx100m -XX:+PrintGC -XX:G1HeapRegionSize=1m -XX:+UseG1GC  HumongousAlloc

    29  *

    30  */

    31 import java.lang.management.GarbageCollectorMXBean;

    32 import java.lang.management.ManagementFactory;

    33 import java.util.List;

    34 

    35 public class HumongousAlloc {

    36 

    37     public static byte[] dummy;

    38     private static int sleepFreq = 40;

    39     private static int sleepTime = 1000;

    40     private static double size = 0.75;

    41     private static int iterations = 50;

    42     private static int MB = 1024 * 1024;

    43 

    44     public static void allocate(int size, int sleepTime, int sleepFreq) throws InterruptedException {

    45         System.out.println("Will allocate objects of size: " + size

    46                 + " bytes and sleep for " + sleepTime

    47                 + " ms after every " + sleepFreq + "th allocation.");

    48         int count = 0;

    49         while (count < iterations) {

    50             for (int i = 0; i < sleepFreq; i++) {

    51                 dummy = new byte[size - 16];

    52             }

    53             Thread.sleep(sleepTime);

    54             count++;

    55         }

    56     }

    57 

    58     public static void main(String[] args) throws InterruptedException {

    59         allocate((int) (size * MB), sleepTime, sleepFreq);

    60         List<GarbageCollectorMXBean> collectors = ManagementFactory.getGarbageCollectorMXBeans();

    61         for (GarbageCollectorMXBean collector : collectors) {

    62             if (collector.getName().contains("G1 Old")) {

    63                long count = collector.getCollectionCount();

    64                 if (count > 0) {

    65                     throw new RuntimeException("Failed: FullGCs should not have happened. The number of FullGC run is " + count);

    66                 }

    67                 else {

    68                     System.out.println("Passed.");

    69                 }

    70             }

    71         }

    72     }

    73 }

    74