jdk

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/*
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 * Copyright (c) 2014, 2020, Oracle and/or its affiliates. All rights reserved.
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
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 * This code is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License version 2 only, as
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 * published by the Free Software Foundation.
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 *
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * accompanied this code).
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 *
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 * You should have received a copy of the GNU General Public License version
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 *
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * or visit www.oracle.com if you need additional information or have any
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 * questions.
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 */
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package gc;
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/**
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 * @test TestSoftReferencesBehaviorOnOOME
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 * @key randomness
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 * @summary Tests that all SoftReferences has been cleared at time of OOM.
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 * @requires vm.gc != "Z"
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 * @requires vm.gc != "Shenandoah"
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 * @library /test/lib
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 * @modules java.base/jdk.internal.misc
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 * @run main/othervm -Xmx128m gc.TestSoftReferencesBehaviorOnOOME 512 2k
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 * @run main/othervm -Xmx128m gc.TestSoftReferencesBehaviorOnOOME 128k 256k
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 * @run main/othervm -Xmx128m gc.TestSoftReferencesBehaviorOnOOME 2k 32k
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 */
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import jdk.test.lib.Utils;
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import jdk.test.lib.Asserts;
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import java.lang.ref.SoftReference;
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import java.util.LinkedList;
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import java.util.Random;
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public class TestSoftReferencesBehaviorOnOOME {
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    /**
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     * Test generates a lot of soft references to objects with random payloads.
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     * Then it provokes OOME and checks that all SoftReferences has been gone
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     * @param args - [minSize] [maxSize] [freq]
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     *  where
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     *  - minSize - min size of random objects
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     *  - maxSize - max size of random objects
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     */
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    public static void main(String[] args) {
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        long minSize = DEFAULT_MIN_SIZE;
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        long maxSize = DEFAULT_MAX_SIZE;
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        if ( args.length >= 2) {
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            maxSize = getBytesCount(args[1]);
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        }
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        if ( args.length >= 1) {
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            minSize = getBytesCount(args[0]);
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        }
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        new TestSoftReferencesBehaviorOnOOME().softReferencesOom(minSize, maxSize);
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    }
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    /**
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     * Test that all SoftReferences has been cleared at time of OOM.
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     */
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    void softReferencesOom(long minSize, long maxSize) {
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        System.out.format( "minSize = %d, maxSize = %d%n", minSize, maxSize );
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        LinkedList<SoftReference<byte[]>> arrSoftRefs = new LinkedList<>();
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        staticRef = arrSoftRefs;
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        LinkedList<byte[]> arrObjects = new LinkedList<>();
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        staticRef = arrObjects;
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        long multiplier = maxSize - minSize;
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        long numberOfNotNulledObjects = 0;
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        try {
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            // Lets allocate as many as we can - taking size of all SoftRerefences
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            // by minimum. So it can provoke some GC but we surely will allocate enough.
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            long numSofts = (long) ((0.95 * Runtime.getRuntime().totalMemory()) / minSize);
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            System.out.println("num Soft: " + numSofts);
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            while (numSofts-- > 0) {
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                int allocationSize = ((int) (RND_GENERATOR.nextDouble() * multiplier))
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                            + (int)minSize;
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                arrSoftRefs.add(new SoftReference<byte[]>(new byte[allocationSize]));
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            }
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            System.out.println("free: " + Runtime.getRuntime().freeMemory());
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            // provoke OOME.
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            while (true) {
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                arrObjects.add(new byte[(int) Runtime.getRuntime().totalMemory()]);
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            }
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        } catch (OutOfMemoryError oome) {
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            // Clear allocated ballast, so we don't get another OOM.
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            staticRef = null;
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            arrObjects = null;
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            long oomSoftArraySize = arrSoftRefs.size();
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            for (SoftReference<byte[]> sr : arrSoftRefs) {
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                Object o = sr.get();
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                if (o != null) {
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                    numberOfNotNulledObjects++;
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                }
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            }
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            // Make sure we clear all refs before we return failure
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            arrSoftRefs = null;
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            Asserts.assertFalse(numberOfNotNulledObjects > 0,
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                    "" + numberOfNotNulledObjects + " out of "
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                    + oomSoftArraySize + " SoftReferences was not "
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                    + "null at time of OutOfMemoryError"
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            );
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        } finally {
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            Asserts.assertTrue(arrObjects == null, "OOME hasn't been provoked");
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            Asserts.assertTrue(arrSoftRefs == null, "OOME hasn't been provoked");
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        }
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    }
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    private static final long getBytesCount(String arg) {
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        String postfixes = "kMGT";
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        long mod = 1;
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        if (arg.trim().length() >= 2) {
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            mod = postfixes.indexOf(arg.trim().charAt(arg.length() - 1));
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            if (mod != -1) {
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                mod = (long) Math.pow(1024, mod+1);
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                arg = arg.substring(0, arg.length() - 1);
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            } else {
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                mod = 1; // 10^0
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            }
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        }
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        return Long.parseLong(arg) * mod;
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    }
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    private static final Random RND_GENERATOR = Utils.getRandomInstance();
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    private static final long DEFAULT_MIN_SIZE = 512;
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    private static final long DEFAULT_MAX_SIZE = 1024;
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    private static Object staticRef; // to prevent compile optimisations
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}
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