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import jdk.test.lib.process.OutputAnalyzer;
import jdk.test.lib.Platform;
import jdk.test.lib.process.ProcessTools;

/*
 * @test
 * @bug 8226416
 * @summary Test the MonitorUsedDeflationThreshold and NoAsyncDeflationProgressMax options.
 * @modules java.base/jdk.internal.misc
 * @library /test/lib
 * @run driver MonitorUsedDeflationThresholdTest
 */

public class MonitorUsedDeflationThresholdTest {
    public static final int DELAY_SECS = 10;
    public static int inflate_count = 0;
    public static Object[] monitors;

    public static void do_work(int count) {
        System.out.println("Recursion count=" + count);
        if (count > inflate_count) {
            System.out.println("Exceeded inflate_count=" + inflate_count);

            System.out.println("Delaying for " + DELAY_SECS + " secs.");
            try {
                Thread.sleep(DELAY_SECS * 1000);
            } catch (InterruptedException ie) {
                // ignore InterruptedException
            }
            System.out.println("Done delaying for " + DELAY_SECS + " secs.");
            return;
        }

        synchronized(monitors[count]) {
            try {
                monitors[count].wait(1);  // force inflation
            } catch (InterruptedException ie) {
                // ignore InterruptedException
            }
            do_work(count + 1);
        }
    }

    public static void usage() {
        System.err.println("Usage: java " +
                           "MonitorUsedDeflationThresholdTest inflate_count");
    }

    public static void main(String[] args) throws Exception {
        if (args.length == 0) {
            // Without args we invoke the test in a java sub-process:
            ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(
                // Test doesn't need much Java heap:
                "-Xmx100M",
                // AvgMonitorsPerThreadEstimate == 1 means we'll start with
                // an in_use_list_ceiling of <n-threads> plus a couple of
                // of monitors for threads that call Object.wait().
                "-XX:+UnlockDiagnosticVMOptions",
                "-XX:AvgMonitorsPerThreadEstimate=1",
                // Enable monitorinflation logging so we can see that
                // MonitorUsedDeflationThreshold and
                // NoAsyncDeflationProgressMaxoption are working.
                "-Xlog:monitorinflation=info",
                // Enable some safepoint logging for diagnostic purposes.
                "-Xlog:safepoint+cleanup=info",
                "-Xlog:safepoint+stats=debug",
                // Run the test with inflate_count == 33 since that
                // reproduced the bug with JDK13. Anything above the
                // in_use_list_ceiling will do the trick.
                "MonitorUsedDeflationThresholdTest", "33");

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

            // This mesg means:
            // - AvgMonitorsPerThreadEstimate == 1 reduced in_use_list_ceiling
            //   to a small number.
            // - and we crossed MonitorUsedDeflationThreshold:
            output_detail.shouldMatch("begin deflating: .*");
            System.out.println("Found beginning of a deflation cycle.");

            // This mesg means we hit NoAsyncDeflationProgressMax and
            // had to adjust the in_use_list_ceiling:
            String too_many = output_detail.firstMatch("Too many deflations without progress; .*", 0);
            if (too_many == null) {
                output_detail.reportDiagnosticSummary();
                throw new RuntimeException("Did not find too_many string in output.\n");
            }
            System.out.println("too_many='" + too_many + "'");

            System.out.println("PASSED.");
            return;
        }
        // else we are the exec'd java subprocess, so run the actual test:

        try {
            inflate_count = Integer.decode(args[0]);
        } catch (NumberFormatException nfe) {
            usage();
            throw new RuntimeException("ERROR: '" + args[0] +
                                       "': bad inflate_count.");
        }

        System.out.println("Hello from MonitorUsedDeflationThresholdTest!");
        System.out.println("inflate_count=" + inflate_count);

        monitors = new Object[inflate_count + 1];
        for (int i = 1; i <= inflate_count; i++) {
            monitors[i] = new Object();
        }
        do_work(1);
    }
}