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src/hotspot/share/runtime/synchronizer.hpp

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rev 58110 : v2.09a with 8235795, 8235931 and 8236035 extracted; rebased to jdk-14+28; merge with 8236035.patch.cr1; merge with 8235795.patch.cr1; merge with 8236035.patch.cr2; merge with 8235795.patch.cr2; merge with 8235795.patch.cr3.

@@ -30,10 +30,11 @@
 #include "runtime/basicLock.hpp"
 #include "runtime/handles.hpp"
 #include "runtime/perfData.hpp"
 
 class ObjectMonitor;
+class ObjectMonitorHandle;
 class ThreadsList;
 
 #ifndef OM_CACHE_LINE_SIZE
 // Use DEFAULT_CACHE_LINE_SIZE if not already specified for
 // the current build platform.

@@ -41,14 +42,14 @@
 #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
+  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 {
   friend class VMStructs;

@@ -106,13 +107,14 @@
   static void om_release(Thread* self, ObjectMonitor* m,
                          bool FromPerThreadAlloc);
   static void om_flush(Thread* self);
 
   // Inflate light weight monitor to heavy weight monitor
-  static ObjectMonitor* inflate(Thread* self, oop obj, const InflateCause cause);
+  static void inflate(ObjectMonitorHandle* omh_p, Thread* self, oop obj,
+                      const InflateCause cause);
   // This version is only for internal use
-  static void inflate_helper(oop obj);
+  static void inflate_helper(ObjectMonitorHandle* omh_p, oop obj);
   static const char* inflate_cause_name(const InflateCause cause);
 
   // Returns the identity hash value for an oop
   // NOTE: It may cause monitor inflation
   static intptr_t identity_hash_value_for(Handle obj);

@@ -130,34 +132,56 @@
 
   // GC: we current use aggressive monitor deflation policy
   // Basically we deflate all monitors that are not busy.
   // An adaptive profile-based deflation policy could be used if needed
   static void deflate_idle_monitors(DeflateMonitorCounters* counters);
+  static void deflate_idle_monitors_using_JT();
+  static void deflate_global_idle_monitors_using_JT();
+  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,
                                   int* 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,
+                                           int* count_p,
+                                           ObjectMonitor** free_head_p,
+                                           ObjectMonitor** free_tail_p,
+                                           ObjectMonitor** saved_mid_in_use_p);
   static bool deflate_monitor(ObjectMonitor* mid, oop obj,
                               ObjectMonitor** free_head_p,
                               ObjectMonitor** free_tail_p);
-  static bool is_cleanup_needed();
+  static bool deflate_monitor_using_JT(ObjectMonitor* mid,
+                                       ObjectMonitor** free_head_p,
+                                       ObjectMonitor** free_tail_p);
+  static bool is_async_deflation_needed();
   static bool needs_monitor_scavenge();
+  static bool is_safepoint_deflation_needed();
+  static bool is_async_deflation_requested() { return _is_async_deflation_requested; }
+  static bool is_special_deflation_requested() { return _is_special_deflation_requested; }
+  static void set_is_async_deflation_requested(bool new_value) { _is_async_deflation_requested = new_value; }
+  static void set_is_special_deflation_requested(bool new_value) { _is_special_deflation_requested = new_value; }
+  static jlong time_since_last_async_deflation_ms();
   static void oops_do(OopClosure* f);
   // Process oops in thread local used monitors
   static void thread_local_used_oops_do(Thread* thread, OopClosure* f);
 
   // debugging
   static void audit_and_print_stats(bool on_exit);
   static void chk_free_entry(JavaThread* jt, ObjectMonitor* n,
                              outputStream * out, int *error_cnt_p);
   static void chk_global_free_list_and_count(outputStream * out,
                                              int *error_cnt_p);
+  static void chk_global_wait_list_and_count(outputStream * out,
+                                             int *error_cnt_p);
   static void chk_global_in_use_list_and_count(outputStream * out,
                                                int *error_cnt_p);
   static void chk_in_use_entry(JavaThread* jt, ObjectMonitor* n,
                                outputStream * out, int *error_cnt_p);
   static void chk_per_thread_in_use_list_and_count(JavaThread *jt,

@@ -168,16 +192,21 @@
                                                  int *error_cnt_p);
   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);
+
  private:
   friend class SynchronizerTest;
 
   enum { _BLOCKSIZE = 128 };
   // global list of blocks of monitors
   static PaddedObjectMonitor* g_block_list;
+  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)
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