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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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24
25#ifndef SHARE_GC_SHARED_CARDGENERATION_HPP
26#define SHARE_GC_SHARED_CARDGENERATION_HPP
27
28// Class CardGeneration is a generation that is covered by a card table,
29// and uses a card-size block-offset array to implement block_start.
30
31#include "gc/shared/generation.hpp"
32
33class BlockOffsetSharedArray;
34class CardTableRS;
35class CompactibleSpace;
36
37class CardGeneration: public Generation {
38 friend class VMStructs;
39 protected:
40 // This is shared with other generations.
41 CardTableRS* _rs;
42 // This is local to this generation.
43 BlockOffsetSharedArray* _bts;
44
45 // Current shrinking effect: this damps shrinking when the heap gets empty.
46 size_t _shrink_factor;
47
48 size_t _min_heap_delta_bytes; // Minimum amount to expand.
49
50 // Some statistics from before gc started.
51 // These are gathered in the gc_prologue (and should_collect)
52 // to control growing/shrinking policy in spite of promotions.
53 size_t _capacity_at_prologue;
54 size_t _used_at_prologue;
55
56 CardGeneration(ReservedSpace rs, size_t initial_byte_size, CardTableRS* remset);
57
58 virtual void assert_correct_size_change_locking() = 0;
59
60 virtual CompactibleSpace* space() const = 0;
61
62 public:
63
64 // Attempt to expand the generation by "bytes". Expand by at a
65 // minimum "expand_bytes". Return true if some amount (not
66 // necessarily the full "bytes") was done.
67 virtual bool expand(size_t bytes, size_t expand_bytes);
68
69 // Shrink generation with specified size
70 virtual void shrink(size_t bytes);
71
72 virtual void compute_new_size();
73
74 virtual void clear_remembered_set();
75
76 virtual void invalidate_remembered_set();
77
78 virtual void prepare_for_verify();
79
80 // Grow generation with specified size (returns false if unable to grow)
81 bool grow_by(size_t bytes);
82 // Grow generation to reserved size.
83 bool grow_to_reserved();
84
85 size_t capacity() const;
86 size_t used() const;
87 size_t free() const;
88 MemRegion used_region() const;
89
90 void space_iterate(SpaceClosure* blk, bool usedOnly = false);
91
92 void younger_refs_iterate(OopsInGenClosure* blk, uint n_threads);
93
94 bool is_in(const void* p) const;
95
96 CompactibleSpace* first_compaction_space() const;
97};
98
99#endif // SHARE_GC_SHARED_CARDGENERATION_HPP
100