ReleaseCommittedMemory.java

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/*
 * @test
 * @bug 8013120
 * @summary Release committed memory and make sure NMT handles it correctly
 * @key nmt regression
 * @library /testlibrary /testlibrary/whitebox
 * @build ReleaseCommittedMemory
 * @run main ClassFileInstaller sun.hotspot.WhiteBox
 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI -XX:NativeMemoryTracking=detail ReleaseCommittedMemory
 */

import sun.hotspot.WhiteBox;

public class ReleaseCommittedMemory {

  public static void main(String args[]) throws Exception {
    WhiteBox wb = WhiteBox.getWhiteBox();
    long reserveSize = 256 * 1024;
    long addr;

    addr = wb.NMTReserveMemory(reserveSize);
    wb.NMTCommitMemory(addr, 128*1024);
    wb.NMTReleaseMemory(addr, reserveSize);
  }
}