TestEagerReclaimHumongousRegions.java revision 9727:f944761a3ce3 
1/*
2 * Copyright (c) 2014, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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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
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22 */
23
24/*
25 * @test TestEagerReclaimHumongousRegions
26 * @bug 8027959
27 * @summary Test to make sure that eager reclaim of humongous objects work. We simply try to fill
28 * up the heap with humongous objects that should be eagerly reclaimable to avoid Full GC.
29 * @key gc
30 * @library /testlibrary
31 * @modules java.base/sun.misc
32 *          java.management
33 */
34
35import java.util.regex.Pattern;
36import java.util.regex.Matcher;
37import java.util.LinkedList;
38
39import jdk.test.lib.OutputAnalyzer;
40import jdk.test.lib.ProcessTools;
41import jdk.test.lib.Asserts;
42
43class ReclaimRegionFast {
44    public static final int M = 1024*1024;
45
46    public static LinkedList<Object> garbageList = new LinkedList<Object>();
47
48    public static void genGarbage() {
49        for (int i = 0; i < 32*1024; i++) {
50            garbageList.add(new int[100]);
51        }
52        garbageList.clear();
53    }
54
55    // A large object referenced by a static.
56    static int[] filler = new int[10 * M];
57
58    public static void main(String[] args) {
59
60        int[] large = new int[M];
61
62        Object ref_from_stack = large;
63
64        for (int i = 0; i < 100; i++) {
65            // A large object that will be reclaimed eagerly.
66            large = new int[6*M];
67            genGarbage();
68            // Make sure that the compiler cannot completely remove
69            // the allocation of the large object until here.
70            System.out.println(large);
71        }
72
73        // Keep the reference to the first object alive.
74        System.out.println(ref_from_stack);
75    }
76}
77
78public class TestEagerReclaimHumongousRegions {
79    public static void main(String[] args) throws Exception {
80        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
81            "-XX:+UseG1GC",
82            "-Xms128M",
83            "-Xmx128M",
84            "-Xmn16M",
85            "-Xlog:gc",
86            ReclaimRegionFast.class.getName());
87
88        Pattern p = Pattern.compile("Full GC");
89
90        OutputAnalyzer output = new OutputAnalyzer(pb.start());
91
92        int found = 0;
93        Matcher m = p.matcher(output.getStdout());
94        while (m.find()) { found++; }
95        System.out.println("Issued " + found + " Full GCs");
96        Asserts.assertLT(found, 10, "Found that " + found + " Full GCs were issued. This is larger than the bound. Eager reclaim seems to not work at all");
97
98        output.shouldHaveExitValue(0);
99    }
100}
101