8226416: MonitorUsedDeflationThreshold can cause repeated async deflation requests

Reviewed-by: dholmes, coleenp

test/hotspot/jtreg/runtime/Monitor/MonitorUsedDeflationThresholdTest.java

@@ -0,0 +1,135 @@
+/*
+ * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ * 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
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+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);
+    }
+}