Thu, 21 Aug 2014 16:44:41 +0200
8055098: WB API should be extended to provide information about size and age of object.
Summary: Extend the WhiteBox API to provide information about the size and age of objects. Further add a mechanism to trigger a young GC.
Reviewed-by: tschatzl, sjohanss
Contributed-by: Leonid Mesnik <leonid.mesnik@oracle.com>
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1REGIONTOSPACEMAPPER_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1REGIONTOSPACEMAPPER_HPP
28 #include "gc_implementation/g1/g1PageBasedVirtualSpace.hpp"
29 #include "memory/allocation.hpp"
30 #include "utilities/debug.hpp"
32 class 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 virtual void on_commit(uint start_idx, size_t num_regions) = 0;
37 };
39 // Maps region based commit/uncommit requests to the underlying page sized virtual
40 // space.
41 class G1RegionToSpaceMapper : public CHeapObj<mtGC> {
42 private:
43 G1MappingChangedListener* _listener;
44 protected:
45 // Backing storage.
46 G1PageBasedVirtualSpace _storage;
47 size_t _commit_granularity;
48 size_t _region_granularity;
49 // Mapping management
50 BitMap _commit_map;
52 G1RegionToSpaceMapper(ReservedSpace rs, size_t commit_granularity, size_t region_granularity, MemoryType type);
54 void fire_on_commit(uint start_idx, size_t num_regions);
55 public:
56 MemRegion reserved() { return _storage.reserved(); }
58 void set_mapping_changed_listener(G1MappingChangedListener* listener) { _listener = listener; }
60 virtual ~G1RegionToSpaceMapper() {
61 _commit_map.resize(0, /* in_resource_area */ false);
62 }
64 bool is_committed(uintptr_t idx) const {
65 return _commit_map.at(idx);
66 }
68 virtual void commit_regions(uintptr_t start_idx, size_t num_regions = 1) = 0;
69 virtual void uncommit_regions(uintptr_t start_idx, size_t num_regions = 1) = 0;
71 // Creates an appropriate G1RegionToSpaceMapper for the given parameters.
72 // The byte_translation_factor defines how many bytes in a region correspond to
73 // a single byte in the data structure this mapper is for.
74 // Eg. in the card table, this value corresponds to the size a single card
75 // table entry corresponds to.
76 static G1RegionToSpaceMapper* create_mapper(ReservedSpace rs,
77 size_t os_commit_granularity,
78 size_t region_granularity,
79 size_t byte_translation_factor,
80 MemoryType type);
81 };
83 #endif /* SHARE_VM_GC_IMPLEMENTATION_G1_G1REGIONTOSPACEMAPPER_HPP */