1/*
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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_PARALLEL_ADJOININGGENERATIONS_HPP
26#define SHARE_GC_PARALLEL_ADJOININGGENERATIONS_HPP
27
28#include "gc/parallel/adjoiningVirtualSpaces.hpp"
29#include "gc/parallel/asPSOldGen.hpp"
30#include "gc/parallel/asPSYoungGen.hpp"
31
32
33// Contains two generations that both use an AdjoiningVirtualSpaces.
34// The two generations are adjacent in the reserved space for the
35// heap. Each generation has a virtual space and shrinking and
36// expanding of the generations can still be down with that
37// virtual space as was previously done. If expanding of reserved
38// size of a generation is required, the adjacent generation
39// must be shrunk. Adjusting the boundary between the generations
40// is called for in this class.
41
42class AdjoiningGenerations : public CHeapObj<mtGC> {
43 friend class VMStructs;
44 private:
45 // Move boundary up to expand old gen. Checks are made to
46 // determine if the move can be done with specified limits.
47 void request_old_gen_expansion(size_t desired_change_in_bytes);
48 // Move boundary down to expand young gen.
49 bool request_young_gen_expansion(size_t desired_change_in_bytes);
50
51 protected:
52 AdjoiningGenerations();
53 // The young generation and old generation, respectively
54 PSYoungGen* _young_gen;
55 PSOldGen* _old_gen;
56
57 // The spaces used by the two generations.
58 AdjoiningVirtualSpaces* _virtual_spaces;
59
60 public:
61 AdjoiningGenerations(ReservedSpace rs);
62
63 // Accessors
64 PSYoungGen* young_gen() { return _young_gen; }
65 PSOldGen* old_gen() { return _old_gen; }
66
67 AdjoiningVirtualSpaces* virtual_spaces() { return _virtual_spaces; }
68
69 // Additional space is needed in the old generation. Check
70 // the available space and attempt to move the boundary if more space
71 // is needed. The growth is not guaranteed to occur.
72 void adjust_boundary_for_old_gen_needs(size_t desired_change_in_bytes);
73 // Similarly for a growth of the young generation.
74 void adjust_boundary_for_young_gen_needs(size_t eden_size, size_t survivor_size);
75
76 // Return the total byte size of the reserved space
77 // for the adjoining generations.
78 virtual size_t reserved_byte_size();
79
80 // Return new AdjoiningGenerations instance based on arguments (specifically - whether heap is heterogeneous).
81 static AdjoiningGenerations* create_adjoining_generations(ReservedSpace rs);
82};
83#endif // SHARE_GC_PARALLEL_ADJOININGGENERATIONS_HPP
84