22 * |
22 * |
23 */ |
23 */ |
24 #ifndef SHARE_VM_MEMORY_METACHUNK_HPP |
24 #ifndef SHARE_VM_MEMORY_METACHUNK_HPP |
25 #define SHARE_VM_MEMORY_METACHUNK_HPP |
25 #define SHARE_VM_MEMORY_METACHUNK_HPP |
26 |
26 |
27 // Metachunk - Quantum of allocation from a Virtualspace |
27 #include "memory/allocation.hpp" |
28 // Metachunks are reused (when freed are put on a global freelist) and |
28 #include "utilities/debug.hpp" |
29 // have no permanent association to a SpaceManager. |
29 #include "utilities/globalDefinitions.hpp" |
30 |
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31 // +--------------+ <- end |
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32 // | | --+ ---+ |
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33 // | | | free | |
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34 // | | | | |
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35 // | | | | capacity |
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36 // | | | | |
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37 // | | <- top --+ | |
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38 // | | ---+ | |
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39 // | | | used | |
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40 // | | | | |
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41 // | | | | |
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42 // +--------------+ <- bottom ---+ ---+ |
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43 |
30 |
44 class VirtualSpaceNode; |
31 class VirtualSpaceNode; |
45 |
32 |
46 class Metachunk VALUE_OBJ_CLASS_SPEC { |
33 // Super class of Metablock and Metachunk to allow them to |
47 // link to support lists of chunks |
34 // be put on the FreeList and in the BinaryTreeDictionary. |
48 Metachunk* _next; |
35 template <class T> |
49 Metachunk* _prev; |
36 class Metabase VALUE_OBJ_CLASS_SPEC { |
50 VirtualSpaceNode* _container; |
37 size_t _word_size; |
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38 T* _next; |
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39 T* _prev; |
51 |
40 |
52 MetaWord* _bottom; |
41 protected: |
53 MetaWord* _end; |
42 Metabase(size_t word_size) : _word_size(word_size), _next(NULL), _prev(NULL) {} |
54 MetaWord* _top; |
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55 size_t _word_size; |
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56 // Used in a guarantee() so included in the Product builds |
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57 // even through it is only for debugging. |
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58 bool _is_free; |
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59 |
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60 // Metachunks are allocated out of a MetadataVirtualSpace and |
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61 // and use some of its space to describe itself (plus alignment |
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62 // considerations). Metadata is allocated in the rest of the chunk. |
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63 // This size is the overhead of maintaining the Metachunk within |
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64 // the space. |
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65 static size_t _overhead; |
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66 |
43 |
67 public: |
44 public: |
68 Metachunk(size_t word_size , VirtualSpaceNode* container); |
45 T* next() const { return _next; } |
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46 T* prev() const { return _prev; } |
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47 void set_next(T* v) { _next = v; assert(v != this, "Boom");} |
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48 void set_prev(T* v) { _prev = v; assert(v != this, "Boom");} |
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49 void clear_next() { set_next(NULL); } |
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50 void clear_prev() { set_prev(NULL); } |
69 |
51 |
70 // Used to add a Metachunk to a list of Metachunks |
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71 void set_next(Metachunk* v) { _next = v; assert(v != this, "Boom");} |
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72 void set_prev(Metachunk* v) { _prev = v; assert(v != this, "Boom");} |
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73 void set_container(VirtualSpaceNode* v) { _container = v; } |
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74 |
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75 MetaWord* allocate(size_t word_size); |
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76 |
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77 // Accessors |
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78 Metachunk* next() const { return _next; } |
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79 Metachunk* prev() const { return _prev; } |
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80 VirtualSpaceNode* container() const { return _container; } |
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81 MetaWord* bottom() const { return _bottom; } |
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82 MetaWord* end() const { return _end; } |
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83 MetaWord* top() const { return _top; } |
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84 size_t word_size() const { return _word_size; } |
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85 size_t size() const volatile { return _word_size; } |
52 size_t size() const volatile { return _word_size; } |
86 void set_size(size_t v) { _word_size = v; } |
53 void set_size(size_t v) { _word_size = v; } |
87 bool is_free() { return _is_free; } |
54 |
88 void set_is_free(bool v) { _is_free = v; } |
55 void link_next(T* ptr) { set_next(ptr); } |
89 static size_t overhead() { return _overhead; } |
56 void link_prev(T* ptr) { set_prev(ptr); } |
90 void clear_next() { set_next(NULL); } |
57 void link_after(T* ptr) { |
91 void link_prev(Metachunk* ptr) { set_prev(ptr); } |
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92 uintptr_t* end() { return ((uintptr_t*) this) + size(); } |
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93 bool cantCoalesce() const { return false; } |
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94 void link_next(Metachunk* ptr) { set_next(ptr); } |
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95 void link_after(Metachunk* ptr){ |
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96 link_next(ptr); |
58 link_next(ptr); |
97 if (ptr != NULL) ptr->link_prev(this); |
59 if (ptr != NULL) ptr->link_prev((T*)this); |
98 } |
60 } |
99 |
61 |
100 // Reset top to bottom so chunk can be reused. |
62 uintptr_t* end() const { return ((uintptr_t*) this) + size(); } |
101 void reset_empty() { _top = (_bottom + _overhead); _next = NULL; _prev = NULL; } |
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102 bool is_empty() { return _top == (_bottom + _overhead); } |
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103 |
63 |
104 // used (has been allocated) |
64 bool cantCoalesce() const { return false; } |
105 // free (available for future allocations) |
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106 // capacity (total size of chunk) |
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107 size_t used_word_size() const; |
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108 size_t free_word_size() const; |
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109 size_t capacity_word_size()const; |
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110 |
65 |
111 // Debug support |
66 // Debug support |
112 #ifdef ASSERT |
67 #ifdef ASSERT |
113 void* prev_addr() const { return (void*)&_prev; } |
68 void* prev_addr() const { return (void*)&_prev; } |
114 void* next_addr() const { return (void*)&_next; } |
69 void* next_addr() const { return (void*)&_next; } |
115 void* size_addr() const { return (void*)&_word_size; } |
70 void* size_addr() const { return (void*)&_word_size; } |
116 #endif |
71 #endif |
117 bool verify_chunk_in_free_list(Metachunk* tc) const { return true; } |
72 bool verify_chunk_in_free_list(T* tc) const { return true; } |
118 bool verify_par_locked() { return true; } |
73 bool verify_par_locked() { return true; } |
119 |
74 |
120 void assert_is_mangled() const {/* Don't check "\*/} |
75 void assert_is_mangled() const {/* Don't check "\*/} |
121 |
76 |
122 NOT_PRODUCT(void mangle();) |
77 bool is_free() { return true; } |
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78 }; |
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79 |
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80 // Metachunk - Quantum of allocation from a Virtualspace |
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81 // Metachunks are reused (when freed are put on a global freelist) and |
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82 // have no permanent association to a SpaceManager. |
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83 |
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84 // +--------------+ <- end --+ --+ |
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85 // | | | | |
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86 // | | | free | |
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87 // | | | | |
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88 // | | | | size | capacity |
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89 // | | | | |
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90 // | | <- top -- + | |
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91 // | | | | |
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92 // | | | used | |
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93 // | | | | |
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94 // | | | | |
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95 // +--------------+ <- bottom --+ --+ |
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96 |
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97 class Metachunk : public Metabase<Metachunk> { |
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98 friend class TestMetachunk; |
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99 // The VirtualSpaceNode containing this chunk. |
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100 VirtualSpaceNode* _container; |
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101 |
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102 // Current allocation top. |
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103 MetaWord* _top; |
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104 |
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105 DEBUG_ONLY(bool _is_tagged_free;) |
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106 |
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107 MetaWord* initial_top() const { return (MetaWord*)this + overhead(); } |
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108 MetaWord* top() const { return _top; } |
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109 |
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110 public: |
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111 // Metachunks are allocated out of a MetadataVirtualSpace and |
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112 // and use some of its space to describe itself (plus alignment |
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113 // considerations). Metadata is allocated in the rest of the chunk. |
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114 // This size is the overhead of maintaining the Metachunk within |
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115 // the space. |
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116 |
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117 // Alignment of each allocation in the chunks. |
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118 static size_t object_alignment(); |
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119 |
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120 // Size of the Metachunk header, including alignment. |
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121 static size_t overhead(); |
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122 |
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123 Metachunk(size_t word_size , VirtualSpaceNode* container); |
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124 |
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125 MetaWord* allocate(size_t word_size); |
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126 |
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127 VirtualSpaceNode* container() const { return _container; } |
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128 |
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129 MetaWord* bottom() const { return (MetaWord*) this; } |
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130 |
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131 // Reset top to bottom so chunk can be reused. |
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132 void reset_empty() { _top = initial_top(); clear_next(); clear_prev(); } |
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133 bool is_empty() { return _top == initial_top(); } |
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134 |
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135 // used (has been allocated) |
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136 // free (available for future allocations) |
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137 size_t word_size() const { return size(); } |
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138 size_t used_word_size() const; |
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139 size_t free_word_size() const; |
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140 |
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141 #ifdef ASSERT |
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142 void mangle(); |
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143 bool is_tagged_free() { return _is_tagged_free; } |
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144 void set_is_tagged_free(bool v) { _is_tagged_free = v; } |
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145 #endif |
123 |
146 |
124 void print_on(outputStream* st) const; |
147 void print_on(outputStream* st) const; |
125 void verify(); |
148 void verify(); |
126 }; |
149 }; |
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150 |
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151 // Metablock is the unit of allocation from a Chunk. |
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152 // |
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153 // A Metablock may be reused by its SpaceManager but are never moved between |
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154 // SpaceManagers. There is no explicit link to the Metachunk |
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155 // from which it was allocated. Metablock may be deallocated and |
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156 // put on a freelist but the space is never freed, rather |
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157 // the Metachunk it is a part of will be deallocated when it's |
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158 // associated class loader is collected. |
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159 |
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160 class Metablock : public Metabase<Metablock> { |
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161 friend class VMStructs; |
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162 public: |
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163 Metablock(size_t word_size) : Metabase<Metablock>(word_size) {} |
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164 }; |
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165 |
127 #endif // SHARE_VM_MEMORY_METACHUNK_HPP |
166 #endif // SHARE_VM_MEMORY_METACHUNK_HPP |