src/hotspot/share/runtime/serviceThread.cpp

rev 56044 : imported patch 8230184.patch
rev 56046 : v2.00 -> v2.05 (CR5/v2.05/8-for-jdk13) patches combined into one; merge with 8229212.patch; merge with jdk-14+11; merge with 8230184.patch.
rev 56049 : Merge the remainder of the lock-free monitor list changes from v2.06 with v2.06a and v2.06b after running the changes through the edit scripts; merge pieces from dcubed.monitor_deflate_conc.v2.06d in dcubed.monitor_deflate_conc.v2.06[ac]; merge pieces from dcubed.monitor_deflate_conc.v2.06e into dcubed.monitor_deflate_conc.v2.06c; merge with jdk-14+11; test work around for test/jdk/tools/jlink/multireleasejar/JLinkMultiReleaseJarTest.java should not been needed anymore.

@@ -107,10 +107,11 @@
     bool stringtable_work = false;
     bool symboltable_work = false;
     bool resolved_method_table_work = false;
     bool protection_domain_table_work = false;
     bool oopstorage_work = false;
+    bool deflate_idle_monitors = false;
     JvmtiDeferredEvent jvmti_event;
     {
       // Need state transition ThreadBlockInVM so that this thread
       // will be handled by safepoint correctly when this thread is
       // notified at a safepoint.

@@ -132,14 +133,18 @@
               (has_dcmd_notification_event = DCmdFactory::has_pending_jmx_notification()) |
               (stringtable_work = StringTable::has_work()) |
               (symboltable_work = SymbolTable::has_work()) |
               (resolved_method_table_work = ResolvedMethodTable::has_work()) |
               (protection_domain_table_work = SystemDictionary::pd_cache_table()->has_work()) |
-              (oopstorage_work = OopStorage::has_cleanup_work_and_reset())
+              (oopstorage_work = OopStorage::has_cleanup_work_and_reset()) |
+              (deflate_idle_monitors = ObjectSynchronizer::is_async_deflation_needed())
              ) == 0) {
         // Wait until notified that there is some work to do.
-        ml.wait();
+        // If AsyncDeflateIdleMonitors, then we wait for
+        // GuaranteedSafepointInterval so that is_async_deflation_needed()
+        // is checked at the same interval.
+        ml.wait(AsyncDeflateIdleMonitors ? GuaranteedSafepointInterval : 0);
       }
 
       if (has_jvmti_events) {
         jvmti_event = JvmtiDeferredEventQueue::dequeue();
       }

@@ -178,10 +183,31 @@
     }
 
     if (oopstorage_work) {
       cleanup_oopstorages(oopstorages, oopstorage_count);
     }
+
+    if (deflate_idle_monitors) {
+      // Deflate any global idle monitors.
+      ObjectSynchronizer::deflate_global_idle_monitors_using_JT();
+
+      int count = 0;
+      for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
+        if (jt->om_in_use_count > 0 && !jt->is_exiting()) {
+          // This JavaThread is using ObjectMonitors so deflate any that
+          // are idle unless this JavaThread is exiting; do not race with
+          // ObjectSynchronizer::om_flush().
+          ObjectSynchronizer::deflate_per_thread_idle_monitors_using_JT(jt);
+          count++;
+        }
+      }
+      if (count > 0) {
+        log_debug(monitorinflation)("did async deflation of idle monitors for %d thread(s).", count);
+      }
+      // The ServiceThread's async deflation request has been processed.
+      ObjectSynchronizer::set_is_async_deflation_requested(false);
+    }
   }
 }
 
 bool ServiceThread::is_service_thread(Thread* thread) {
   return thread == _instance;