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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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,
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package jdk.jfr.event.oldobject;

import java.io.IOException;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;

import jdk.jfr.Recording;
import jdk.jfr.consumer.RecordedEvent;
import jdk.jfr.consumer.RecordingFile;
import jdk.jfr.internal.test.WhiteBox;
import jdk.test.lib.jfr.EventNames;
import jdk.test.lib.jfr.Events;

/**
 * @test
 * @key jfr
 * @requires vm.hasJFR
 * @requires vm.gc == "null"
 * @library /test/lib /test/jdk
 * @modules jdk.jfr/jdk.jfr.internal.test
 * @run main/othervm -XX:TLABSize=2k jdk.jfr.event.oldobject.TestLastKnownHeapUsage
 */
public class TestLastKnownHeapUsage {

    public final static List<Object> heap = new ArrayList<>();

    public static void main(String[] args) throws Exception {
        WhiteBox.setWriteAllObjectSamples(true);
        long last = 0;
        for (int i = 1; i <= 5; i++) {
            long heapUsage = recordOldObjects(i);
            System.out.println("Recording: " + i + " heapUsage=" + heapUsage);
            if (heapUsage < last) {
                throw new Exception("Unexpect decrease of heap usage");
            }
        }
    }

    private static long recordOldObjects(int index) throws IOException {
        try (Recording r = new Recording()) {
            r.enable(EventNames.OldObjectSample).withStackTrace().with("cutoff", "infinity");
            r.start();
            System.gc();
            for (int i = 0; i < 20; i++) {
                heap.add(new byte[1_000_000]);
            }
            System.gc();
            r.stop();
            Path p = Paths.get("recording-" + index + ".jfr");
            r.dump(p);
            List<RecordedEvent> events = RecordingFile.readAllEvents(p);
            Events.hasEvents(events);
            long max = 0;
            for (RecordedEvent e : RecordingFile.readAllEvents(p)) {
                long heapUsage = Events.assertField(e, "lastKnownHeapUsage").atLeast(0L).below(1_000_000_000L).getValue();
                max = Math.max(max, heapUsage);
            }
            return max;
        }
    }
}