1 /*

     2  * Copyright (c) 2014, 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.

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    23 

    24 /*

    25  * @test TestEagerReclaimHumongousRegionsClearMarkBits

    26  * @bug 8051973

    27  * @summary Test to make sure that eager reclaim of humongous objects correctly clears

    28  * mark bitmaps at reclaim.

    29  * @key gc

    30  * @library /testlibrary

    31  */

    32 

    33 import java.util.ArrayList;

    34 import java.util.LinkedList;

    35 import java.util.Random;

    36 

    37 import com.oracle.java.testlibrary.OutputAnalyzer;

    38 import com.oracle.java.testlibrary.ProcessTools;

    39 

    40 // An object that has a few references to other instances to slow down marking.

    41 class ObjectWithSomeRefs {

    42     public ObjectWithSomeRefs other1;

    43     public ObjectWithSomeRefs other2;

    44     public ObjectWithSomeRefs other3;

    45     public ObjectWithSomeRefs other4;

    46 }

    47 

    48 class ReclaimRegionFast {

    49     public static final long MAX_MILLIS_FOR_RUN = 50 * 1000; // The maximum runtime for the actual test.

    50 

    51     public static final int M = 1024*1024;

    52 

    53     public static LinkedList<Object> garbageList = new LinkedList<Object>();

    54 

    55     public static void genGarbage(Object large) {

    56         for (int i = 0; i < 64*1024; i++) {

    57             Object[] garbage = new Object[50];

    58             garbage[0] = large;

    59             garbageList.add(garbage);

    60         }

    61         garbageList.clear();

    62     }

    63 

    64     public static ArrayList<ObjectWithSomeRefs> longList = new ArrayList<ObjectWithSomeRefs>();

    65 

    66     public static void main(String[] args) {

    67 

    68         for (int i = 0; i < 16*1024; i++) {

    69              longList.add(new ObjectWithSomeRefs());

    70         }

    71 

    72         Random rnd = new Random();

    73         for (int i = 0; i < longList.size(); i++) {

    74              int len = longList.size();

    75              longList.get(i).other1 = longList.get(rnd.nextInt(len));

    76              longList.get(i).other2 = longList.get(rnd.nextInt(len));

    77              longList.get(i).other3 = longList.get(rnd.nextInt(len));

    78              longList.get(i).other4 = longList.get(rnd.nextInt(len));

    79         }

    80 

    81         int[] large1 = new int[M];

    82         int[] large2 = null;

    83         int[] large3 = null;

    84         int[] large4 = null;

    85 

    86         Object ref_from_stack = large1;

    87 

    88         long start_millis = System.currentTimeMillis();

    89 

    90         for (int i = 0; i < 20; i++) {

    91             long current_millis = System.currentTimeMillis();

    92             if ((current_millis - start_millis) > MAX_MILLIS_FOR_RUN) {

    93               System.out.println("Finishing test because maximum runtime exceeded");

    94               break;

    95             }

    96             // A set of large objects that will be reclaimed eagerly - and hopefully marked.

    97             large1 = new int[M - 20];

    98             large2 = new int[M - 20];

    99             large3 = new int[M - 20];

   100             large4 = new int[M - 20];

   101             genGarbage(large1);

   102             // Make sure that the compiler cannot completely remove

   103             // the allocation of the large object until here.

   104             System.out.println(large1 + " " + large2 + " " + large3 + " " + large4);

   105         }

   106 

   107         // Keep the reference to the first object alive.

   108         System.out.println(ref_from_stack);

   109     }

   110 }

   111 

   112 public class TestEagerReclaimHumongousRegionsClearMarkBits {

   113     public static void main(String[] args) throws Exception {

   114         ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(

   115             "-XX:+UseG1GC",

   116             "-Xms128M",

   117             "-Xmx128M",

   118             "-Xmn2M",

   119             "-XX:G1HeapRegionSize=1M",

   120             "-XX:InitiatingHeapOccupancyPercent=0", // Want to have as much as possible initial marks.

   121             "-XX:+PrintGC",

   122             "-XX:+VerifyAfterGC",

   123             "-XX:ConcGCThreads=1", // Want to make marking as slow as possible.

   124             "-XX:+IgnoreUnrecognizedVMOptions", // G1VerifyBitmaps is develop only.

   125             "-XX:+G1VerifyBitmaps",

   126             ReclaimRegionFast.class.getName());

   127         OutputAnalyzer output = new OutputAnalyzer(pb.start());

   128         output.shouldHaveExitValue(0);

   129     }

   130 }

   131