TestSoftReferencesBehaviorOnOOME.java revision 8362:08b5dfe9bcb5 
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23
24/**
25 * @test TestSoftReferencesBehaviorOnOOME
26 * @key gc
27 * @summary Tests that all SoftReferences has been cleared at time of OOM.
28 * @library /testlibrary
29 * @modules java.base/sun.misc
30 *          java.management
31 * @build TestSoftReferencesBehaviorOnOOME
32 * @run main/othervm -Xmx128m TestSoftReferencesBehaviorOnOOME 512 2k
33 * @run main/othervm -Xmx128m TestSoftReferencesBehaviorOnOOME 128k 256k
34 * @run main/othervm -Xmx128m TestSoftReferencesBehaviorOnOOME 2k 32k
35 */
36import jdk.test.lib.Utils;
37import jdk.test.lib.Asserts;
38import java.lang.ref.SoftReference;
39import java.util.LinkedList;
40import java.util.Random;
41
42public class TestSoftReferencesBehaviorOnOOME {
43
44    /**
45     * Test generates a lot of soft references to objects with random payloads.
46     * Then it provokes OOME and checks that all SoftReferences has been gone
47     * @param args - [minSize] [maxSize] [freq]
48     *  where
49     *  - minSize - min size of random objects
50     *  - maxSize - max size of random objects
51     */
52    public static void main(String[] args) {
53        long minSize = DEFAULT_MIN_SIZE;
54        long maxSize = DEFAULT_MAX_SIZE;
55
56        if ( args.length >= 2) {
57            maxSize = getBytesCount(args[1]);
58        }
59
60        if ( args.length >= 1) {
61            minSize = getBytesCount(args[0]);
62        }
63
64        new TestSoftReferencesBehaviorOnOOME().softReferencesOom(minSize, maxSize);
65    }
66
67    /**
68     * Test that all SoftReferences has been cleared at time of OOM.
69     */
70    void softReferencesOom(long minSize, long maxSize) {
71        System.out.format( "minSize = %d, maxSize = %d%n", minSize, maxSize );
72
73        LinkedList<SoftReference> arrSoftRefs = new LinkedList();
74        staticRef = arrSoftRefs;
75        LinkedList arrObjects = new LinkedList();
76        staticRef = arrObjects;
77
78        long multiplier = maxSize - minSize;
79        long numberOfNotNulledObjects = 0;
80
81        try {
82
83            // Lets allocate as many as we can - taking size of all SoftRerefences
84            // by minimum. So it can provoke some GC but we surely will allocate enough.
85            long numSofts = (long) ((0.95 * Runtime.getRuntime().totalMemory()) / minSize);
86            System.out.println("num Soft: " + numSofts);
87
88            while (numSofts-- > 0) {
89                int allocationSize = ((int) (RND_GENERATOR.nextDouble() * multiplier))
90                            + (int)minSize;
91                arrSoftRefs.add(new SoftReference(new byte[allocationSize]));
92            }
93
94            System.out.println("free: " + Runtime.getRuntime().freeMemory());
95
96            // provoke OOME.
97            while (true) {
98                arrObjects.add(new byte[(int) Runtime.getRuntime().totalMemory()]);
99            }
100
101        } catch (OutOfMemoryError oome) {
102
103            // Clear allocated ballast, so we don't get another OOM.
104            staticRef = null;
105            arrObjects = null;
106            long oomSoftArraySize = arrSoftRefs.size();
107
108            for (SoftReference sr : arrSoftRefs) {
109                Object o = sr.get();
110
111                if (o != null) {
112                    numberOfNotNulledObjects++;
113                }
114            }
115
116            // Make sure we clear all refs before we return failure
117            arrSoftRefs = null;
118            Asserts.assertFalse(numberOfNotNulledObjects > 0,
119                    "" + numberOfNotNulledObjects + " out of "
120                    + oomSoftArraySize + " SoftReferences was not "
121                    + "null at time of OutOfMemoryError"
122            );
123        } finally {
124            Asserts.assertTrue(arrObjects == null, "OOME hasn't been provoked");
125            Asserts.assertTrue(arrSoftRefs == null, "OOME hasn't been provoked");
126        }
127    }
128
129    private static final long getBytesCount(String arg) {
130        String postfixes = "kMGT";
131        long mod = 1;
132
133        if (arg.trim().length() >= 2) {
134            mod = postfixes.indexOf(arg.trim().charAt(arg.length() - 1));
135
136            if (mod != -1) {
137                mod = (long) Math.pow(1024, mod+1);
138                arg = arg.substring(0, arg.length() - 1);
139            } else {
140                mod = 1; // 10^0
141            }
142        }
143
144        return Long.parseLong(arg) * mod;
145    }
146
147    private static final Random RND_GENERATOR = Utils.getRandomInstance();
148    private static final long DEFAULT_MIN_SIZE = 512;
149    private static final long DEFAULT_MAX_SIZE = 1024;
150    private static Object staticRef; // to prevent compile optimisations
151}
152