src/hotspot/share/gc/shenandoah/shenandoahThreadLocalData.hpp

@@ -39,29 +39,55 @@
  private:
    char _gc_state;
    // Evacuation OOM state
    uint8_t                 _oom_scope_nesting_level;
    bool                    _oom_during_evac;
+   bool                    _plab_allows_promotion; // If false, no more promotion by this thread during this evacuation phase.
    SATBMarkQueue           _satb_mark_queue;
+ 
+   // Thread-local allocation buffer for object evacuations.
+   // In generational mode, it is exclusive to the young generation.
    PLAB* _gclab;
    size_t _gclab_size;
    double _paced_time;
  
+   // Thread-local allocation buffer only used in generational mode.
+   // Used both by mutator threads and by GC worker threads
+   // for evacuations within the old generation and
+   // for promotions from the young generation into the old generation.
+   PLAB* _plab;
+   size_t _plab_size;
+ 
+   size_t _plab_evacuated;
+   size_t _plab_promoted;
+   size_t _plab_preallocated_promoted;
+   bool   _plab_retries_enabled;
+ 
    ShenandoahThreadLocalData() :
      _gc_state(0),
      _oom_scope_nesting_level(0),
      _oom_during_evac(false),
      _satb_mark_queue(&ShenandoahBarrierSet::satb_mark_queue_set()),
      _gclab(NULL),
      _gclab_size(0),
-     _paced_time(0) {
+     _paced_time(0),
+     _plab(NULL),
+     _plab_size(0),
+     _plab_evacuated(0),
+     _plab_promoted(0),
+     _plab_preallocated_promoted(0),
+     _plab_retries_enabled(true) {
    }
  
    ~ShenandoahThreadLocalData() {
      if (_gclab != NULL) {
        delete _gclab;
      }
+     if (_plab != NULL) {
+       ShenandoahHeap::heap()->retire_plab(_plab);
+       delete _plab;
+     }
    }
  
    static ShenandoahThreadLocalData* data(Thread* thread) {
      assert(UseShenandoahGC, "Sanity");
      return thread->gc_data<ShenandoahThreadLocalData>();

@@ -95,10 +121,12 @@
    static void initialize_gclab(Thread* thread) {
      assert (thread->is_Java_thread() || thread->is_Worker_thread(), "Only Java and GC worker threads are allowed to get GCLABs");
      assert(data(thread)->_gclab == NULL, "Only initialize once");
      data(thread)->_gclab = new PLAB(PLAB::min_size());
      data(thread)->_gclab_size = 0;
+     data(thread)->_plab = new PLAB(PLAB::min_size());
+     data(thread)->_plab_size = 0;
    }
  
    static PLAB* gclab(Thread* thread) {
      return data(thread)->_gclab;
    }

@@ -109,10 +137,86 @@
  
    static void set_gclab_size(Thread* thread, size_t v) {
      data(thread)->_gclab_size = v;
    }
  
+   static PLAB* plab(Thread* thread) {
+     return data(thread)->_plab;
+   }
+ 
+   static size_t plab_size(Thread* thread) {
+     return data(thread)->_plab_size;
+   }
+ 
+   static void set_plab_size(Thread* thread, size_t v) {
+     data(thread)->_plab_size = v;
+   }
+ 
+   static void enable_plab_retries(Thread* thread) {
+     data(thread)->_plab_retries_enabled = true;
+   }
+ 
+   static void disable_plab_retries(Thread* thread) {
+     data(thread)->_plab_retries_enabled = false;
+   }
+ 
+   static bool plab_retries_enabled(Thread* thread) {
+     return data(thread)->_plab_retries_enabled;
+   }
+ 
+   static void enable_plab_promotions(Thread* thread) {
+     data(thread)->_plab_allows_promotion = true;
+   }
+ 
+   static void disable_plab_promotions(Thread* thread) {
+     data(thread)->_plab_allows_promotion = false;
+   }
+ 
+   static bool allow_plab_promotions(Thread* thread) {
+     return data(thread)->_plab_allows_promotion;
+   }
+ 
+   static void reset_plab_evacuated(Thread* thread) {
+     data(thread)->_plab_evacuated = 0;
+   }
+ 
+   static void add_to_plab_evacuated(Thread* thread, size_t increment) {
+     data(thread)->_plab_evacuated += increment;
+   }
+ 
+   static void subtract_from_plab_evacuated(Thread* thread, size_t increment) {
+     data(thread)->_plab_evacuated -= increment;
+   }
+ 
+   static size_t get_plab_evacuated(Thread* thread) {
+     return data(thread)->_plab_evacuated;
+   }
+ 
+   static void reset_plab_promoted(Thread* thread) {
+     data(thread)->_plab_promoted = 0;
+   }
+ 
+   static void add_to_plab_promoted(Thread* thread, size_t increment) {
+     data(thread)->_plab_promoted += increment;
+   }
+ 
+   static void subtract_from_plab_promoted(Thread* thread, size_t increment) {
+     data(thread)->_plab_promoted -= increment;
+   }
+ 
+   static size_t get_plab_promoted(Thread* thread) {
+     return data(thread)->_plab_promoted;
+   }
+ 
+   static void set_plab_preallocated_promoted(Thread* thread, size_t value) {
+     data(thread)->_plab_preallocated_promoted = value;
+   }
+ 
+   static size_t get_plab_preallocated_promoted(Thread* thread) {
+     return data(thread)->_plab_preallocated_promoted;
+   }
+ 
    static void add_paced_time(Thread* thread, double v) {
      data(thread)->_paced_time += v;
    }
  
    static double paced_time(Thread* thread) {