TestCapacityUntilGCWrapAround.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * 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
 * @key gc
 * @bug 8049831
 * @library /testlibrary /testlibrary/whitebox
 * @build TestCapacityUntilGCWrapAround
 * @run main ClassFileInstaller sun.hotspot.WhiteBox
 *                              sun.hotspot.WhiteBox$WhiteBoxPermission
 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI TestCapacityUntilGCWrapAround
 */

import sun.hotspot.WhiteBox;

import com.oracle.java.testlibrary.Asserts;
import com.oracle.java.testlibrary.Platform;

public class TestCapacityUntilGCWrapAround {
    private static long MB = 1024 * 1024;
    private static long GB = 1024 * MB;
    private static long MAX_UINT = 4 * GB - 1; // On 32-bit platforms

    public static void main(String[] args) {
        if (Platform.is32bit()) {
            WhiteBox wb = WhiteBox.getWhiteBox();

            long before = wb.metaspaceCapacityUntilGC();
            // Now force possible overflow of capacity_until_GC.
            long after = wb.incMetaspaceCapacityUntilGC(MAX_UINT);

            Asserts.assertGTE(after, before,
                              "Increasing with MAX_UINT should not cause wrap around: " + after + " < " + before);
            Asserts.assertLTE(after, MAX_UINT,
                              "Increasing with MAX_UINT should not cause value larger than MAX_UINT:" + after);
        }
    }
}