src/hotspot/share/gc/g1/g1HotCardCache.hpp

rev 56992 : imported patch 8227739-merge-scan-rs-update-rs-cost

*** 79,88 ****
--- 79,93 ----
  
    volatile size_t _hot_cache_par_claimed_idx;
  
    char _pad_after[DEFAULT_CACHE_LINE_SIZE];
  
+   // Records whether insertion overflowed the hot card cache at least once. This
+   // avoids the need for a separate atomic counter of how many valid entries are
+   // in the HCC.
+   bool _cache_wrapped_around;
+ 
    // The number of cached cards a thread claims when flushing the cache
    static const int ClaimChunkSize = 32;
  
   public:
    static bool default_use_cache() {
*** 130,145 ****
--- 135,155 ----
    }
  
    // Zeros the values in the card counts table for the given region
    void reset_card_counts(HeapRegion* hr);
  
+   // Number of entries in the HCC.
+   size_t num_entries() const {
+     return _cache_wrapped_around ? _hot_cache_size : _hot_cache_idx + 1;
+   }
   private:
    void reset_hot_cache_internal() {
      assert(_hot_cache != NULL, "Logic");
      _hot_cache_idx = 0;
      for (size_t i = 0; i < _hot_cache_size; i++) {
        _hot_cache[i] = NULL;
      }
+     _cache_wrapped_around = false;
    }
  };
  
  #endif // SHARE_GC_G1_G1HOTCARDCACHE_HPP