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

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 *

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

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 *

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

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/*

 * @test TestPLABSizeBounds

 * @bug 8134857

 * @summary Regression test to ensure that G1 supports PLAB sizes of half a region size.

 * @requires vm.gc=="G1" | vm.gc=="null"

 * @key gc

 * @library /testlibrary

 * @modules java.base/sun.misc

 *          java.management

 */

import java.util.ArrayList;

import jdk.test.lib.OutputAnalyzer;

import jdk.test.lib.Platform;

import jdk.test.lib.ProcessTools;

public class TestPLABSizeBounds {

    public static final int M = 1024 * 1024;

    /**

     * Starts the VM with the given region size and the given PLAB size arguments. The VM start should

     * succeed if shouldSucceed is true, otherwise it should fail.

     *

     * @param regionSize The region size the VM should be started with in bytes.

     * @param plabSize The young and old gen PLAB sizes the VM should be started with in machine words.

     * @param shouldSucceed The expected result of the VM invocation.

     */

    public static void runTest(int regionSize, int plabSize, boolean shouldSucceed) throws Exception {

        ArrayList<String> testArguments = new ArrayList<String>();

        testArguments.add("-XX:+UseG1GC");

        testArguments.add("-Xmx256M");

        testArguments.add("-XX:G1HeapRegionSize=" + regionSize);

        testArguments.add("-XX:YoungPLABSize=" + plabSize);

        testArguments.add("-XX:OldPLABSize=" + plabSize);

        testArguments.add(GCTest.class.getName());

        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(testArguments.toArray(new String[0]));

        OutputAnalyzer output = new OutputAnalyzer(pb.start());

        if (shouldSucceed) {

            output.shouldHaveExitValue(0);

        } else {

            output.shouldHaveExitValue(1);

        }

    }

    public static void runRegionTest(int regionSize) throws Exception {

        final int regionSizeInBytes = regionSize * M;

        final int wordSize = Platform.is32bit() ? 4 : 8;

        runTest(regionSizeInBytes, (regionSizeInBytes / wordSize) / 2 - 1, true);

        runTest(regionSizeInBytes, (regionSizeInBytes / wordSize) / 2, true);

        runTest(regionSizeInBytes, (regionSizeInBytes / wordSize) / 2 + 1, false);

    }

    public static void main(String[] args) throws Exception {

        runRegionTest(1);

        runRegionTest(2);

        runRegionTest(4);

        runRegionTest(8);

        runRegionTest(16);

        runRegionTest(32);

    }

    static class GCTest {

        public static void main(String [] args) {

            System.out.println("Test completed.");

        }

    }

}