8291418: adjust monitor deflation logging and deflate_idle_monitors use

Reviewed-by: dholmes, stuefe, pchilanomate

Author: Daniel D. Daugherty

src/hotspot/share/runtime/synchronizer.cpp

@@ -1497,6 +1497,8 @@ size_t ObjectSynchronizer::deflate_idle_monitors(ObjectMonitorsHashtable* table)
 
   // Deflate some idle ObjectMonitors.
   size_t deflated_count = deflate_monitor_list(current, ls, &timer, table);
+  size_t unlinked_count = 0;
+  size_t deleted_count = 0;
   if (deflated_count > 0 || is_final_audit()) {
     // There are ObjectMonitors that have been deflated or this is the
     // final audit and all the remaining ObjectMonitors have been
@@ -1506,8 +1508,7 @@ size_t ObjectSynchronizer::deflate_idle_monitors(ObjectMonitorsHashtable* table)
     // Unlink deflated ObjectMonitors from the in-use list.
     ResourceMark rm;
     GrowableArray<ObjectMonitor*> delete_list((int)deflated_count);
-    size_t unlinked_count = _in_use_list.unlink_deflated(current, ls, &timer,
-                                                         &delete_list);
+    unlinked_count = _in_use_list.unlink_deflated(current, ls, &timer, &delete_list);
     if (current->is_Java_thread()) {
       if (ls != NULL) {
         timer.stop();
@@ -1533,7 +1534,6 @@ size_t ObjectSynchronizer::deflate_idle_monitors(ObjectMonitorsHashtable* table)
 
     // After the handshake, safely free the ObjectMonitors that were
     // deflated in this cycle.
-    size_t deleted_count = 0;
     for (ObjectMonitor* monitor: delete_list) {
       delete monitor;
       deleted_count++;
@@ -1544,13 +1544,14 @@ size_t ObjectSynchronizer::deflate_idle_monitors(ObjectMonitorsHashtable* table)
                           deleted_count, ls, &timer);
       }
     }
+    assert(unlinked_count == deleted_count, "must be");
   }
 
   if (ls != NULL) {
     timer.stop();
-    if (deflated_count != 0 || log_is_enabled(Debug, monitorinflation)) {
-      ls->print_cr("deflated " SIZE_FORMAT " monitors in %3.7f secs",
-                   deflated_count, timer.seconds());
+    if (deflated_count != 0 || unlinked_count != 0 || log_is_enabled(Debug, monitorinflation)) {
+      ls->print_cr("deflated_count=" SIZE_FORMAT ", {unlinked,deleted}_count=" SIZE_FORMAT " monitors in %3.7f secs",
+                   deflated_count, unlinked_count, timer.seconds());
     }
     ls->print_cr("end deflating: in_use_list stats: ceiling=" SIZE_FORMAT ", count=" SIZE_FORMAT ", max=" SIZE_FORMAT,
                  in_use_list_ceiling(), _in_use_list.count(), _in_use_list.max());
@@ -1659,17 +1660,18 @@ void ObjectSynchronizer::do_final_audit_and_print_stats() {
     return;
   }
   set_is_final_audit();
+  log_info(monitorinflation)("Starting the final audit.");
 
   if (log_is_enabled(Info, monitorinflation)) {
-    // Do a deflation in order to reduce the in-use monitor population
+    // Do deflations in order to reduce the in-use monitor population
     // that is reported by ObjectSynchronizer::log_in_use_monitor_details()
     // which is called by ObjectSynchronizer::audit_and_print_stats().
-    while (ObjectSynchronizer::deflate_idle_monitors(/* ObjectMonitorsHashtable is not needed here */ nullptr) >= (size_t)MonitorDeflationMax) {
+    while (deflate_idle_monitors(/* ObjectMonitorsHashtable is not needed here */ nullptr) > 0) {
       ; // empty
     }
     // The other audit_and_print_stats() call is done at the Debug
     // level at a safepoint in SafepointSynchronize::do_cleanup_tasks.
-    ObjectSynchronizer::audit_and_print_stats(true /* on_exit */);
+    audit_and_print_stats(true /* on_exit */);
   }
 }
 

src/hotspot/share/runtime/vmOperations.cpp

@@ -287,7 +287,7 @@ void VM_ThreadDump::doit() {
     // when there are a lot of inflated monitors. So we deflate idle monitors and
     // gather information about owned monitors at the same time.
     tablep = &table;
-    while (ObjectSynchronizer::deflate_idle_monitors(tablep) >= (size_t)MonitorDeflationMax) {
+    while (ObjectSynchronizer::deflate_idle_monitors(tablep) > 0) {
       ; /* empty */
     }
   }