hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp

rev 7369 : 8061715: gc/g1/TestShrinkAuxiliaryData15.java fails with java.lang.RuntimeException: heap decommit failed - after > before
Summary: added WhiteBox methods to count regions and exact aux data sizes
Reviewed-by: jwilhelm, brutisso

@@ -231,11 +231,10 @@
   HeapRegionSet _old_set;
 
   // It keeps track of the humongous regions.
   HeapRegionSet _humongous_set;
 
-  void clear_humongous_is_live_table();
   void eagerly_reclaim_humongous_regions();
 
   // The number of regions we could create by expansion.
   uint _expansion_regions;
 

@@ -301,26 +300,30 @@
   void abandon_gc_alloc_regions();
 
   // Helper for monitoring and management support.
   G1MonitoringSupport* _g1mm;
 
-  // Records whether the region at the given index is kept live by roots or
-  // references from the young generation.
-  class HumongousIsLiveBiasedMappedArray : public G1BiasedMappedArray<bool> {
+  // Records whether the region at the given index is (still) a
+  // candidate for eager reclaim.  Only valid for humongous start
+  // regions; other regions have unspecified values.  Humongous start
+  // regions are initialized at start of collection pause, with
+  // candidates removed from the set as they are found reachable from
+  // roots or the young generation.
+  class HumongousReclaimCandidates : public G1BiasedMappedArray<bool> {
    protected:
     bool default_value() const { return false; }
    public:
     void clear() { G1BiasedMappedArray<bool>::clear(); }
-    void set_live(uint region) {
-      set_by_index(region, true);
+    void set_candidate(uint region, bool value) {
+      set_by_index(region, value);
     }
-    bool is_live(uint region) {
+    bool is_candidate(uint region) {
       return get_by_index(region);
     }
   };
 
-  HumongousIsLiveBiasedMappedArray _humongous_is_live;
+  HumongousReclaimCandidates _humongous_reclaim_candidates;
   // Stores whether during humongous object registration we found candidate regions.
   // If not, we can skip a few steps.
   bool _has_humongous_reclaim_candidates;
 
   volatile unsigned _gc_time_stamp;

@@ -653,19 +656,19 @@
 
   // Do anything common to GC's.
   virtual void gc_prologue(bool full);
   virtual void gc_epilogue(bool full);
 
-  inline void set_humongous_is_live(oop obj);
+  // Modify the reclaim candidate set and test for presence.
+  // These are only valid for starts_humongous regions.
+  inline void set_humongous_reclaim_candidate(uint region, bool value);
+  inline bool is_humongous_reclaim_candidate(uint region);
 
-  bool humongous_is_live(uint region) {
-    return _humongous_is_live.is_live(region);
-  }
+  // Remove from the reclaim candidate set.  Also remove from the
+  // collection set so that later encounters avoid the slow path.
+  inline void set_humongous_is_live(oop obj);
 
-  // Returns whether the given region (which must be a humongous (start) region)
-  // is to be considered conservatively live regardless of any other conditions.
-  bool humongous_region_is_always_live(uint index);
   // Register the given region to be part of the collection set.
   inline void register_humongous_region_with_in_cset_fast_test(uint index);
   // Register regions with humongous objects (actually on the start region) in
   // the in_cset_fast_test table.
   void register_humongous_regions_with_in_cset_fast_test();

@@ -1104,10 +1107,14 @@
   uint max_regions() const { return _hrm.max_length(); }
 
   // The number of regions that are completely free.
   uint num_free_regions() const { return _hrm.num_free_regions(); }
 
+  MemoryUsage get_auxiliary_data_memory_usage() const {
+    return _hrm.get_auxiliary_data_memory_usage();
+  }
+
   // The number of regions that are not completely free.
   uint num_used_regions() const { return num_regions() - num_free_regions(); }
 
   void verify_not_dirty_region(HeapRegion* hr) PRODUCT_RETURN;
   void verify_dirty_region(HeapRegion* hr) PRODUCT_RETURN;