/*

 * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

package gc.g1.humongousObjects;

import gc.testlibrary.Helpers;

import jdk.test.lib.Asserts;

import jdk.test.lib.Utils;

import sun.hotspot.WhiteBox;

import java.io.PrintStream;

import java.math.BigInteger;

import java.util.ArrayList;

import java.util.List;

import java.util.Random;

import java.util.stream.Collectors;

/**

 * @test TestHumongousMovement

 * @summary Checks that Humongous objects are not moved during GC

 * @requires vm.gc.G1

 * @modules java.base/jdk.internal.misc

 * @modules java.management

 * @build sun.hotspot.WhiteBox

 * @run driver ClassFileInstaller sun.hotspot.WhiteBox

 *      sun.hotspot.WhiteBox$WhiteBoxPermission

 * @run main/othervm -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -Xbootclasspath/a:.

 *                   -XX:G1HeapRegionSize=1M -Xms200m -Xmx200m -XX:InitiatingHeapOccupancyPercent=100

 *                   -Xlog:gc=info:file=TestHumongousMovement.log

 *                   gc.g1.humongousObjects.TestHumongousMovement

 */

public class TestHumongousMovement {

    private static class AllocationData {

        private final byte[] allocation;

        public final BigInteger objectAddress;

        public AllocationData(byte[] byteArray) {

            allocation = byteArray;

            objectAddress = new BigInteger(Long.toUnsignedString((WB.getObjectAddress(allocation))));

        }

        public boolean isAddressChanged() {

            return !new BigInteger(Long.toUnsignedString((WB.getObjectAddress(allocation)))).equals(objectAddress);

        }

        public void printDetails(PrintStream out) {

            BigInteger objectAddressAfterGC =

                    new BigInteger(Long.toUnsignedString((WB.getObjectAddress(allocation))));

            out.println(String.format("Object stored address = %d\nObject address after GC = %d\n"

                            + "They are %sequals", objectAddress,

                    objectAddressAfterGC, !objectAddress.equals(objectAddressAfterGC) ? "not " : ""));

        }

    }

    private static final WhiteBox WB = WhiteBox.getWhiteBox();

    // How many allocated humongous objects should be deleted

    private static final double HUMONGOUS_OBJECTS_DELETED_FACTOR = 0.5D;

    // How many of free g1 regions should be used for humongous allocations

    private static final double ALLOCATED_HUMONGOUS_REGIONS_FACTOR = 0.25D;

    public static void main(String[] args) {

        int g1RegionSize = WB.g1RegionSize();

        int byteArrayMemoryOverhead = Helpers.detectByteArrayAllocationOverhead();

        System.out.println("Total " + WB.g1NumMaxRegions() + " regions");

        System.out.println("Total " + WB.g1NumFreeRegions() + " free regions");

        int regionsToAllocate = (int) (WB.g1NumFreeRegions() * ALLOCATED_HUMONGOUS_REGIONS_FACTOR);

        // Sanity check

        Asserts.assertGreaterThan(regionsToAllocate, 0, "Test Bug: no regions to allocate");

        System.out.println("Allocating " + regionsToAllocate + " humongous objects, each 90% of g1 region size");

        List<AllocationData> allocations = new ArrayList<>();

        // 90 % of maximum byte[] that takes one region

        int hSize = (int) ((g1RegionSize - byteArrayMemoryOverhead) * 0.9);

        // Sanity check

        Asserts.assertGreaterThan(hSize, g1RegionSize / 2, "Test Bug: allocation size is not humongous");

        for (int i = 0; i < regionsToAllocate; ++i) {

            allocations.add(new AllocationData(new byte[hSize]));

        }

        Random rnd = Utils.getRandomInstance();

        int toDelete = (int) (allocations.size() * HUMONGOUS_OBJECTS_DELETED_FACTOR);

        for (int i = 0; i < toDelete; ++i) {

            allocations.remove(rnd.nextInt(allocations.size()));

        }

        WB.fullGC();

        List<AllocationData> movedObjects = allocations.stream()

                .filter(AllocationData::isAddressChanged)

                .collect(Collectors.toList());

        if (movedObjects.size() > 0) {

            System.out.println("Test failed - some humongous objects moved after Full GC");

            movedObjects.stream().forEach(a -> a.printDetails(System.out));

            throw new Error("Test failed - some humongous objects moved after Full GC");

        } else {

            System.out.println("Passed");

        }

    }

}