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src/hotspot/share/runtime/objectMonitor.hpp

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rev 56634 : imported patch 8230876.patch
rev 56635 : 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; merge with 8230876.patch; merge with jdk-14+15; merge with jdk-14+18.
rev 56637 : Add OM_CACHE_LINE_SIZE so that ObjectMonitor cache line sizes can be experimented with independently of DEFAULT_CACHE_LINE_SIZE; for SPARC and X64 configs that use 128 for DEFAULT_CACHE_LINE_SIZE, we are experimenting with 64; move _previous_owner_tid and _allocation_state fields to share the cache line with ObjectMonitor::_header; put ObjectMonitor::_ref_count on its own cache line after _owner; add 'int* count_p' parameter to deflate_monitor_list() and deflate_monitor_list_using_JT() and push counter updates down to where the ObjectMonitors are actually removed from the in-use lists; monitors_iterate() async deflation check should use negative ref_count; add 'JavaThread* target' param to deflate_per_thread_idle_monitors_using_JT() add deflate_common_idle_monitors_using_JT() to make it clear which JavaThread* is the target of the work and which is the calling JavaThread* (self); g_free_list, g_om_in_use_list and g_om_in_use_count are now static to synchronizer.cpp (reduce scope); add more diagnostic info to some assert()'s; minor code cleanups and code motion; save_om_ptr() should detect a race with a deflating thread that is bailing out and cause a retry when the ref_count field is not positive; merge with jdk-14+11; add special GC support for TestHumongousClassLoader.java; merge with 8230184.patch; merge with jdk-14+14; merge with jdk-14+18.
rev 56638 : 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; merge with jdk-14+18.
rev 56639 : loosen a couple more counter checks due to races observed in testing; simplify om_release() extraction of mid since list head or cur_mid_in_use is marked; simplify deflate_monitor_list() extraction of mid since there are no parallel deleters due to the safepoint; simplify deflate_monitor_list_using_JT() extraction of mid since list head or cur_mid_in_use is marked; prepend_block_to_lists() - simplify based on David H's comments; does not need load_acquire() or release_store() because of the cmpxchg(); prepend_to_common() - simplify to use mark_next_loop() for m and use mark_list_head() and release_store() for the non-empty list case; add more debugging for "Non-balanced monitor enter/exit" failure mode; fix race in inflate() in the "CASE: neutral" code path; install_displaced_markword_in_object() does not need to clear the header field since that is handled when the ObjectMonitor is moved from the global free list; LSuccess should clear boxReg to set ICC.ZF=1 to avoid depending on existing boxReg contents; update fast_unlock() to detect when object no longer refers to the same ObjectMonitor and take fast path exit instead; clarify fast_lock() code where we detect when object no longer refers to the same ObjectMonitor; add/update comments for movptr() calls where we move a literal into an Address; remove set_owner(); refactor setting of owner field into set_owner_from(2 versions), set_owner_from_BasicLock(), and try_set_owner_from(); the new functions include monitorinflation+owner logging; extract debug code from v2.06 and v2.07 and move to v2.07.debug; change 'jccb' -> 'jcc' and 'jmpb' -> 'jmp' as needed; checkpoint initial version of MacroAssembler::inc_om_ref_count(); update LP64 MacroAssembler::fast_lock() and fast_unlock() to use inc_om_ref_count(); fast_lock() return flag setting logic can use 'testptr(tmpReg, tmpReg)' instead of 'cmpptr(tmpReg, 0)' since that's more efficient; fast_unlock() LSuccess return flag setting logic can use 'testl (boxReg, 0)' instead of 'xorptr(boxReg, boxReg)' since that's more efficient; cleanup "fast-path" vs "fast path" and "slow-path" vs "slow path"; update MacroAssembler::rtm_inflated_locking() to use inc_om_ref_count(); update MacroAssembler::fast_lock() to preserve the flags before decrementing ref_count and restore the flags afterwards; this is more clean than depending on the contents of rax/tmpReg; coleenp CR - refactor async monitor deflation work from ServiceThread::service_thread_entry() to ObjectSynchronizer::deflate_idle_monitors_using_JT(); rehn,eosterlund CR - add support for HandshakeAfterDeflateIdleMonitors for platforms that don't have ObjectMonitor ref_count support implemented in C2 fast_lock() and fast_unlock().

@@ -189,11 +189,10 @@
   volatile jint  _waiters;          // number of waiting threads
  private:
   volatile int _WaitSetLock;        // protects Wait Queue - simple spinlock
 
  public:
-  volatile int visit_marker;
   static void Initialize();
 
   // Only perform a PerfData operation if the PerfData object has been
   // allocated and if the PerfDataManager has not freed the PerfData
   // objects which can happen at normal VM shutdown.

@@ -224,10 +223,11 @@
   // TODO-FIXME: the "offset" routines should return a type of off_t instead of int ...
   // ByteSize would also be an appropriate type.
   static int header_offset_in_bytes()      { return offset_of(ObjectMonitor, _header); }
   static int object_offset_in_bytes()      { return offset_of(ObjectMonitor, _object); }
   static int owner_offset_in_bytes()       { return offset_of(ObjectMonitor, _owner); }
+  static int ref_count_offset_in_bytes()   { return offset_of(ObjectMonitor, _ref_count); }
   static int recursions_offset_in_bytes()  { return offset_of(ObjectMonitor, _recursions); }
   static int cxq_offset_in_bytes()         { return offset_of(ObjectMonitor, _cxq); }
   static int succ_offset_in_bytes()        { return offset_of(ObjectMonitor, _succ); }
   static int EntryList_offset_in_bytes()   { return offset_of(ObjectMonitor, _EntryList); }
 

@@ -270,11 +270,19 @@
   intptr_t  is_entered(Thread* current) const;
 
   void*     owner() const;  // Returns NULL if DEFLATER_MARKER is observed.
   // Returns true if owner field == DEFLATER_MARKER and false otherwise.
   bool      owner_is_DEFLATER_MARKER();
-  void      set_owner(void* owner);
+  // Set _owner field to new_value; current value must match old_value.
+  void      set_owner_from(void* new_value, void* old_value);
+  // Set _owner field to new_value; current value must match old_value1 or old_value2.
+  void      set_owner_from(void* new_value, void* old_value1, void* old_value2);
+  // Set _owner field to self; current value must match basic_lock_p.
+  void      set_owner_from_BasicLock(Thread* self, void* basic_lock_p);
+  // Try to set _owner field to new_value if the current value matches
+  // old_value. Otherwise, does not change the _owner field.
+  void*     try_set_owner_from(void* new_value, void* old_value);
 
   jint      waiters() const;
 
   jint      contentions() const;
   intptr_t  recursions() const                                         { return _recursions; }

@@ -337,10 +345,11 @@
   void      wait(jlong millis, bool interruptable, TRAPS);
   void      notify(TRAPS);
   void      notifyAll(TRAPS);
 
   void      print() const;
+  void      print_debug_style_on(outputStream* st) const;
   void      print_on(outputStream* st) const;
 
 // Use the following at your own risk
   intptr_t  complete_exit(TRAPS);
   void      reenter(intptr_t recursions, TRAPS);
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