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