src/hotspot/share/memory/heap.hpp

rev 54914 : 8223444: Improve CodeHeap Free Space Management
Reviewed-by:

@@ -49,10 +49,12 @@
   };
 
  public:
   // Initialization
   void initialize(size_t length)                 { _header._length = length; set_used(); }
+  // Merging/splitting
+  void set_length(size_t length)                 { _header._length = length; }
 
   // Accessors
   void* allocated_space() const                  { return (void*)(this + 1); }
   size_t length() const                          { return _header._length; }
 

@@ -69,13 +71,10 @@
 
  public:
   // Initialization
   void initialize(size_t length)             { HeapBlock::initialize(length); _link= NULL; }
 
-  // Merging
-  void set_length(size_t l)                  { _header._length = l; }
-
   // Accessors
   FreeBlock* link() const                    { return _link; }
   void set_link(FreeBlock* link)             { _link = link; }
 };
 

@@ -113,29 +112,32 @@
 
   size_t   segment_for(void* p) const            { return ((char*)p - _memory.low()) >> _log2_segment_size; }
   bool     is_segment_unused(int val) const      { return val == free_sentinel; }
   HeapBlock* block_at(size_t i) const            { return (HeapBlock*)(_memory.low() + (i << _log2_segment_size)); }
 
+  // These methods take segment map indices as range boundaries
   void  mark_segmap_as_free(size_t beg, size_t end);
   void  mark_segmap_as_used(size_t beg, size_t end);
+  void invalidate(size_t beg, size_t end, size_t header_bytes);
+  void clear(size_t beg, size_t end);
+  void clear();                                 // clears all heap contents
 
   // Freelist management helpers
   FreeBlock* following_block(FreeBlock* b);
   void insert_after(FreeBlock* a, FreeBlock* b);
   bool merge_right (FreeBlock* a);
 
   // Toplevel freelist management
   void add_to_freelist(HeapBlock* b);
-  FreeBlock* search_freelist(size_t length);
+  HeapBlock* search_freelist(size_t length);
 
   // Iteration helpers
   void*      next_used(HeapBlock* b) const;
   HeapBlock* block_start(void* p) const;
 
   // to perform additional actions on creation of executable code
   void on_code_mapping(char* base, size_t size);
-  void clear();                                 // clears all heap contents
 
  public:
   CodeHeap(const char* name, const int code_blob_type);
 
   // Heap extents

@@ -178,10 +180,11 @@
   static size_t header_size();                   // returns the header size for each heap block
 
   size_t segment_size()         const { return _segment_size; }  // for CodeHeapState
   HeapBlock* first_block() const;                                // for CodeHeapState
   HeapBlock* next_block(HeapBlock* b) const;                     // for CodeHeapState
+  HeapBlock* split_block(HeapBlock* b, size_t split_seg);        // split one block into two
 
   FreeBlock* freelist()         const { return _freelist; }      // for CodeHeapState
 
   size_t allocated_in_freelist() const           { return _freelist_segments * CodeCacheSegmentSize; }
   int    freelist_length()       const           { return _freelist_length; } // number of elements in the freelist