test/hotspot/jtreg/runtime/Metaspace/FragmentMetaspace.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
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 *
 * 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.
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/**
 * @test
 * @library /test/lib
 * @modules java.base/jdk.internal.misc
 * @modules java.compiler
 * @run main/othervm/timeout=200 -Xmx1g FragmentMetaspace
 */

import java.io.IOException;
import jdk.test.lib.classloader.GeneratingCompilingClassLoader;

/**
 * Test that tries to fragment the native memory used by class loaders.
 * This test creates class loaders that load classes of increasing size for every
 * iteration. By increasing the size of the class meta data needed for every iteration
 * we stress the subsystem for allocating native memory for meta data.
 */
public class FragmentMetaspace {

    public static Class<?> c;

    public static void main(String... args) {
        runGrowing(Long.valueOf(System.getProperty("time", "40000")),
            Integer.valueOf(System.getProperty("iterations", "100")));
        // try to clean up and unload classes to decrease
        // class verification time in debug vm
        System.gc();
    }

    private static void runGrowing(long time, int iterations) {
        long startTime = System.currentTimeMillis();
        for (int i = 0; System.currentTimeMillis() < startTime + time && i < iterations; ++i) {
            try {
                GeneratingCompilingClassLoader gcl = new GeneratingCompilingClassLoader();

                // getGeneratedClasses throws a RuntimeException in cases where
                // the javac exit code is not 0. If the original reason for the exception is
                // a "java.lang.OutOfMemoryError: Java heap space",
                // increase the heap size in the @run tag and rerun the test.
                // The heap can be exhausted by this test, but heap exhaustion
                // is not a failure mode of this test and should be ignored.
                c = gcl.getGeneratedClasses(i, 100)[0];
                c.newInstance();
                c = null;

                gcl = null;
            } catch (IOException | InstantiationException | IllegalAccessException ex) {
                throw new RuntimeException(ex);
            } catch (OutOfMemoryError oome) {
                System.out.println("javac failed with OOM; ignored.");
                return;
            }
        }
    }
}