g1RegionToSpaceMapper.hpp revision 8413:92457dfb91bd 
1/*
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24
25#ifndef SHARE_VM_GC_G1_G1REGIONTOSPACEMAPPER_HPP
26#define SHARE_VM_GC_G1_G1REGIONTOSPACEMAPPER_HPP
27
28#include "gc/g1/g1PageBasedVirtualSpace.hpp"
29#include "memory/allocation.hpp"
30#include "utilities/debug.hpp"
31
32class G1MappingChangedListener VALUE_OBJ_CLASS_SPEC {
33 public:
34  // Fired after commit of the memory, i.e. the memory this listener is registered
35  // for can be accessed.
36  // Zero_filled indicates that the memory can be considered as filled with zero bytes
37  // when called.
38  virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled) = 0;
39};
40
41// Maps region based commit/uncommit requests to the underlying page sized virtual
42// space.
43class G1RegionToSpaceMapper : public CHeapObj<mtGC> {
44 private:
45  G1MappingChangedListener* _listener;
46 protected:
47  // Backing storage.
48  G1PageBasedVirtualSpace _storage;
49
50  size_t _region_granularity;
51  // Mapping management
52  BitMap _commit_map;
53
54  G1RegionToSpaceMapper(ReservedSpace rs, size_t used_size, size_t page_size, size_t region_granularity, MemoryType type);
55
56  void fire_on_commit(uint start_idx, size_t num_regions, bool zero_filled);
57 public:
58  MemRegion reserved() { return _storage.reserved(); }
59
60  size_t reserved_size() { return _storage.reserved_size(); }
61  size_t committed_size() { return _storage.committed_size(); }
62
63  void set_mapping_changed_listener(G1MappingChangedListener* listener) { _listener = listener; }
64
65  virtual ~G1RegionToSpaceMapper() {
66    _commit_map.resize(0, /* in_resource_area */ false);
67  }
68
69  bool is_committed(uintptr_t idx) const {
70    return _commit_map.at(idx);
71  }
72
73  virtual void commit_regions(uint start_idx, size_t num_regions = 1) = 0;
74  virtual void uncommit_regions(uint start_idx, size_t num_regions = 1) = 0;
75
76  // Creates an appropriate G1RegionToSpaceMapper for the given parameters.
77  // The actual space to be used within the given reservation is given by actual_size.
78  // This is because some OSes need to round up the reservation size to guarantee
79  // alignment of page_size.
80  // The byte_translation_factor defines how many bytes in a region correspond to
81  // a single byte in the data structure this mapper is for.
82  // Eg. in the card table, this value corresponds to the size a single card
83  // table entry corresponds to in the heap.
84  static G1RegionToSpaceMapper* create_mapper(ReservedSpace rs,
85                                              size_t actual_size,
86                                              size_t page_size,
87                                              size_t region_granularity,
88                                              size_t byte_translation_factor,
89                                              MemoryType type);
90};
91
92#endif /* SHARE_VM_GC_G1_G1REGIONTOSPACEMAPPER_HPP */
93