jdk-24/test/hotspot/jtreg/gc/nvdimm/TestYoungObjectsOnDram.java

/*
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 * 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
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 * questions.
 */

package gc.nvdimm;

/*
 * @test TestYoungObjectsOnDram
 * @summary Check that objects in young generation reside in dram.
 * @requires vm.gc=="null" & os.family != "aix"
 * @requires test.vm.gc.nvdimm
 * @library /test/lib
 * @build sun.hotspot.WhiteBox
 * @run driver ClassFileInstaller sun.hotspot.WhiteBox
 *                                sun.hotspot.WhiteBox$WhiteBoxPermission
 * @run driver gc.nvdimm.TestYoungObjectsOnDram
 */

import jdk.test.lib.process.OutputAnalyzer;
import jdk.test.lib.process.ProcessTools;
import jdk.test.lib.Asserts;
import sun.hotspot.WhiteBox;

import java.util.ArrayList;
import java.util.Collections;

/**
 * Test spawns YoungObjectTest in a separate VM and expects that it
 * completes without a RuntimeException.
 */
public class TestYoungObjectsOnDram {

    public static final int ALLOCATION_SIZE = 100;
    private static String[] commonFlags;

    public static void main(String args[]) throws Exception {
        commonFlags = new String[] {
            "-Xbootclasspath/a:.",
            "-XX:+UnlockExperimentalVMOptions",
            "-XX:+UnlockDiagnosticVMOptions",
            "-XX:+WhiteBoxAPI",
            "-XX:AllocateOldGenAt=" + System.getProperty("test.dir", "."),
            "-XX:SurvivorRatio=1", // Survivor-to-eden ratio is 1:1
            "-Xms10M", "-Xmx10M",
            "-XX:InitialTenuringThreshold=15" // avoid promotion of objects to Old Gen
        };
        runTest("-XX:+UseG1GC");
        runTest("-XX:+UseParallelGC");
    }

    private static void runTest(String... extraFlags) throws Exception {
        ArrayList<String> flags = new ArrayList<>();
        Collections.addAll(flags, commonFlags);
        Collections.addAll(flags, extraFlags);
        flags.add(YoungObjectTest.class.getName());

        ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(true,
                flags.toArray(String[]::new));

        OutputAnalyzer output = new OutputAnalyzer(pb.start());
        System.out.println(output.getStdout());
        output.shouldHaveExitValue(0);
    }
}

/**
 * This class tests that newly created object is in Young generation and resides in DRAM.
 * The necessary condition for this test is running in VM with the following flags:
 * -XX:AllocateOldGenAt=, -XX:InitialTenuringThreshold=15, -XX:SurvivorRatio=1
 */
class YoungObjectTest {
    private static final WhiteBox WB = WhiteBox.getWhiteBox();

    private static void validateYoungObject(Object o) {
        Asserts.assertTrue(!WB.isObjectInOldGen(o),
                "Object is supposed to be in YoungGen");

        long youngObj_addr = WB.getObjectAddress(o);
        long dram_heap_start = WB.dramReservedStart();
        long dram_heap_end = WB.dramReservedEnd();

        Asserts.assertTrue(youngObj_addr >= dram_heap_start && youngObj_addr <= dram_heap_end,
                "Young object does not reside in DRAM");
    }

    public static void main(String args[]) throws Exception {
        // allocate an object
        byte[] youngObj = new byte[TestYoungObjectsOnDram.ALLOCATION_SIZE];
        validateYoungObject(youngObj);

        // Start a Young GC and check that object is still in DRAM.
        // We have used -XX:InitialTenuringThreshold=15 to invoke this test
        WB.youngGC();
        validateYoungObject(youngObj);
    }
}