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src/share/vm/memory/virtualspace.hpp

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  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_RUNTIME_VIRTUALSPACE_HPP
  26 #define SHARE_VM_RUNTIME_VIRTUALSPACE_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 
  30 // ReservedSpace is a data structure for reserving a contiguous address range.
  31 
  32 class ReservedSpace VALUE_OBJ_CLASS_SPEC {
  33   friend class VMStructs;
  34  protected:
  35   char*  _base;
  36   size_t _size;
  37   size_t _noaccess_prefix;
  38   size_t _alignment;
  39   bool   _special;

  40  private:
  41   bool   _executable;
  42 
  43   // ReservedSpace
  44   ReservedSpace(char* base, size_t size, size_t alignment, bool special,
  45                 bool executable);
  46  protected:
  47   void initialize(size_t size, size_t alignment, bool large,
  48                   char* requested_address,
  49                   bool executable);
  50 
  51  public:
  52   // Constructor
  53   ReservedSpace();
  54   // Initialize the reserved space with the given size. If preferred_page_size
  55   // is set, use this as minimum page size/alignment. This may waste some space
  56   // if the given size is not aligned to that value, as the reservation will be
  57   // aligned up to the final alignment in this case.
  58   ReservedSpace(size_t size, size_t preferred_page_size = 0);
  59   ReservedSpace(size_t size, size_t alignment, bool large,


  94 }
  95 
  96 ReservedSpace ReservedSpace::last_part(size_t partition_size)
  97 {
  98   return last_part(partition_size, alignment());
  99 }
 100 
 101 // Class encapsulating behavior specific of memory space reserved for Java heap.
 102 class ReservedHeapSpace : public ReservedSpace {
 103  private:
 104   void try_reserve_heap(size_t size, size_t alignment, bool large,
 105                         char *requested_address);
 106   void try_reserve_range(char *highest_start, char *lowest_start,
 107                          size_t attach_point_alignment, char *aligned_HBMA,
 108                          char *upper_bound, size_t size, size_t alignment, bool large);
 109   void initialize_compressed_heap(const size_t size, size_t alignment, bool large);
 110   // Create protection page at the beginning of the space.
 111   void establish_noaccess_prefix();
 112  public:
 113   // Constructor. Tries to find a heap that is good for compressed oops.
 114   ReservedHeapSpace(size_t size, size_t forced_base_alignment, bool large);
 115   // Returns the base to be used for compression, i.e. so that null can be
 116   // encoded safely and implicit null checks can work.
 117   char *compressed_oop_base() { return _base - _noaccess_prefix; }
 118 };
 119 
 120 // Class encapsulating behavior specific memory space for Code
 121 class ReservedCodeSpace : public ReservedSpace {
 122  public:
 123   // Constructor
 124   ReservedCodeSpace(size_t r_size, size_t rs_align, bool large);
 125 };
 126 
 127 // VirtualSpace is data structure for committing a previously reserved address range in smaller chunks.
 128 
 129 class VirtualSpace VALUE_OBJ_CLASS_SPEC {
 130   friend class VMStructs;
 131  private:
 132   // Reserved area
 133   char* _low_boundary;
 134   char* _high_boundary;




  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_RUNTIME_VIRTUALSPACE_HPP
  26 #define SHARE_VM_RUNTIME_VIRTUALSPACE_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 
  30 // ReservedSpace is a data structure for reserving a contiguous address range.
  31 
  32 class ReservedSpace VALUE_OBJ_CLASS_SPEC {
  33   friend class VMStructs;
  34  protected:
  35   char*  _base;
  36   size_t _size;
  37   size_t _noaccess_prefix;
  38   size_t _alignment;
  39   bool   _special;
  40   const char* _backingFileDir = NULL;
  41  private:
  42   bool   _executable;
  43 
  44   // ReservedSpace
  45   ReservedSpace(char* base, size_t size, size_t alignment, bool special,
  46                 bool executable);
  47  protected:
  48   void initialize(size_t size, size_t alignment, bool large,
  49                   char* requested_address,
  50                   bool executable);
  51 
  52  public:
  53   // Constructor
  54   ReservedSpace();
  55   // Initialize the reserved space with the given size. If preferred_page_size
  56   // is set, use this as minimum page size/alignment. This may waste some space
  57   // if the given size is not aligned to that value, as the reservation will be
  58   // aligned up to the final alignment in this case.
  59   ReservedSpace(size_t size, size_t preferred_page_size = 0);
  60   ReservedSpace(size_t size, size_t alignment, bool large,


  95 }
  96 
  97 ReservedSpace ReservedSpace::last_part(size_t partition_size)
  98 {
  99   return last_part(partition_size, alignment());
 100 }
 101 
 102 // Class encapsulating behavior specific of memory space reserved for Java heap.
 103 class ReservedHeapSpace : public ReservedSpace {
 104  private:
 105   void try_reserve_heap(size_t size, size_t alignment, bool large,
 106                         char *requested_address);
 107   void try_reserve_range(char *highest_start, char *lowest_start,
 108                          size_t attach_point_alignment, char *aligned_HBMA,
 109                          char *upper_bound, size_t size, size_t alignment, bool large);
 110   void initialize_compressed_heap(const size_t size, size_t alignment, bool large);
 111   // Create protection page at the beginning of the space.
 112   void establish_noaccess_prefix();
 113  public:
 114   // Constructor. Tries to find a heap that is good for compressed oops.
 115   ReservedHeapSpace(size_t size, size_t forced_base_alignment, bool large, const char* backingFSforHeap=NULL);
 116   // Returns the base to be used for compression, i.e. so that null can be
 117   // encoded safely and implicit null checks can work.
 118   char *compressed_oop_base() { return _base - _noaccess_prefix; }
 119 };
 120 
 121 // Class encapsulating behavior specific memory space for Code
 122 class ReservedCodeSpace : public ReservedSpace {
 123  public:
 124   // Constructor
 125   ReservedCodeSpace(size_t r_size, size_t rs_align, bool large);
 126 };
 127 
 128 // VirtualSpace is data structure for committing a previously reserved address range in smaller chunks.
 129 
 130 class VirtualSpace VALUE_OBJ_CLASS_SPEC {
 131   friend class VMStructs;
 132  private:
 133   // Reserved area
 134   char* _low_boundary;
 135   char* _high_boundary;


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