--- old/src/hotspot/share/runtime/synchronizer.hpp	2019-08-28 15:04:46.674955759 -0400
+++ new/src/hotspot/share/runtime/synchronizer.hpp	2019-08-28 15:04:46.506955765 -0400
@@ -35,14 +35,20 @@
 class ObjectMonitorHandle;
 class ThreadsList;
 
-typedef PaddedEnd<ObjectMonitor, DEFAULT_CACHE_LINE_SIZE> PaddedObjectMonitor;
+#ifndef OM_CACHE_LINE_SIZE
+// Use DEFAULT_CACHE_LINE_SIZE if not already specified for
+// the current build platform.
+#define OM_CACHE_LINE_SIZE DEFAULT_CACHE_LINE_SIZE
+#endif
+
+typedef PaddedEnd<ObjectMonitor, OM_CACHE_LINE_SIZE> PaddedObjectMonitor;
 
 struct DeflateMonitorCounters {
-  int n_in_use;              // currently associated with objects
-  int n_in_circulation;      // extant
-  int n_scavenged;           // reclaimed (global and per-thread)
-  int per_thread_scavenged;  // per-thread scavenge total
-  double per_thread_times;   // per-thread scavenge times
+  volatile int n_in_use;              // currently associated with objects
+  volatile int n_in_circulation;      // extant
+  volatile int n_scavenged;           // reclaimed (global and per-thread)
+  volatile int per_thread_scavenged;  // per-thread scavenge total
+           double per_thread_times;   // per-thread scavenge times
 };
 
 class ObjectSynchronizer : AllStatic {
@@ -142,19 +148,21 @@
   // An adaptive profile-based deflation policy could be used if needed
   static void deflate_idle_monitors(DeflateMonitorCounters* counters);
   static void deflate_global_idle_monitors_using_JT();
-  static void deflate_per_thread_idle_monitors_using_JT();
-  static void deflate_common_idle_monitors_using_JT(bool is_global, JavaThread* self);
+  static void deflate_per_thread_idle_monitors_using_JT(JavaThread* target);
+  static void deflate_common_idle_monitors_using_JT(bool is_global, JavaThread* target);
   static void deflate_thread_local_monitors(Thread* thread, DeflateMonitorCounters* counters);
   static void prepare_deflate_idle_monitors(DeflateMonitorCounters* counters);
   static void finish_deflate_idle_monitors(DeflateMonitorCounters* counters);
 
   // For a given monitor list: global or per-thread, deflate idle monitors
-  static int deflate_monitor_list(ObjectMonitor** list_p,
+  static int deflate_monitor_list(ObjectMonitor* volatile * list_p,
+                                  int volatile * count_p,
                                   ObjectMonitor** free_head_p,
                                   ObjectMonitor** free_tail_p);
   // For a given in-use monitor list: global or per-thread, deflate idle
   // monitors using a JavaThread.
-  static int deflate_monitor_list_using_JT(ObjectMonitor** list_p,
+  static int deflate_monitor_list_using_JT(ObjectMonitor* volatile * list_p,
+                                           int volatile * count_p,
                                            ObjectMonitor** free_head_p,
                                            ObjectMonitor** free_tail_p,
                                            ObjectMonitor** saved_mid_in_use_p);
@@ -191,11 +199,11 @@
   static void chk_per_thread_free_list_and_count(JavaThread *jt,
                                                  outputStream * out,
                                                  int *error_cnt_p);
-  static void log_in_use_monitor_details(outputStream * out, bool on_exit);
+  static void log_in_use_monitor_details(outputStream * out);
   static int  log_monitor_list_counts(outputStream * out);
   static int  verify_objmon_isinpool(ObjectMonitor *addr) PRODUCT_RETURN0;
 
-  static void do_safepoint_work(DeflateMonitorCounters* _counters);
+  static void do_safepoint_work(DeflateMonitorCounters* counters);
 
  private:
   friend class SynchronizerTest;
@@ -203,21 +211,17 @@
   enum { _BLOCKSIZE = 128 };
   // global list of blocks of monitors
   static PaddedObjectMonitor* volatile g_block_list;
-  // global monitor free list
-  static ObjectMonitor* volatile g_free_list;
-  // global monitor in-use list, for moribund threads,
-  // monitors they inflated need to be scanned for deflation
-  static ObjectMonitor* volatile g_om_in_use_list;
-  // count of entries in g_om_in_use_list
-  static int g_om_in_use_count;
   static volatile bool _is_async_deflation_requested;
   static volatile bool _is_special_deflation_requested;
   static jlong         _last_async_deflation_time_ns;
 
+  // Function to prepend new blocks to the appropriate lists:
+  static void prepend_block_to_lists(PaddedObjectMonitor* new_blk);
+
   // Process oops in all global used monitors (i.e. moribund thread's monitors)
   static void global_used_oops_do(OopClosure* f);
   // Process oops in monitors on the given list
-  static void list_oops_do(ObjectMonitor* list, OopClosure* f);
+  static void list_oops_do(ObjectMonitor* list, int count, OopClosure* f);
 
   // Support for SynchronizerTest access to GVars fields:
   static u_char* get_gvars_addr();