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1 /* |
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2 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. |
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8 * |
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9 * This code is distributed in the hope that it will be useful, but WITHOUT |
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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12 * version 2 for more details (a copy is included in the LICENSE file that |
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13 * accompanied this code). |
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14 * |
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15 * You should have received a copy of the GNU General Public License version |
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16 * 2 along with this work; if not, write to the Free Software Foundation, |
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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18 * |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
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22 * |
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23 */ |
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24 |
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25 #ifndef SHARE_VM_MEMORY_BINARYTREEDICTIONARY_HPP |
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26 #define SHARE_VM_MEMORY_BINARYTREEDICTIONARY_HPP |
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27 |
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28 #include "memory/freeBlockDictionary.hpp" |
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29 #include "memory/freeList.hpp" |
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30 |
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31 /* |
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32 * A binary tree based search structure for free blocks. |
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33 * This is currently used in the Concurrent Mark&Sweep implementation, but |
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34 * will be used for free block management for metadata. |
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35 */ |
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36 |
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37 // A TreeList is a FreeList which can be used to maintain a |
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38 // binary tree of free lists. |
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39 |
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40 template <class Chunk> class TreeChunk; |
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41 template <class Chunk> class BinaryTreeDictionary; |
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42 template <class Chunk> class AscendTreeCensusClosure; |
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43 template <class Chunk> class DescendTreeCensusClosure; |
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44 template <class Chunk> class DescendTreeSearchClosure; |
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45 |
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46 template <class Chunk> |
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47 class TreeList: public FreeList<Chunk> { |
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48 friend class TreeChunk<Chunk>; |
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49 friend class BinaryTreeDictionary<Chunk>; |
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50 friend class AscendTreeCensusClosure<Chunk>; |
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51 friend class DescendTreeCensusClosure<Chunk>; |
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52 friend class DescendTreeSearchClosure<Chunk>; |
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53 |
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54 TreeList<Chunk>* _parent; |
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55 TreeList<Chunk>* _left; |
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56 TreeList<Chunk>* _right; |
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57 |
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58 protected: |
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59 TreeList<Chunk>* parent() const { return _parent; } |
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60 TreeList<Chunk>* left() const { return _left; } |
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61 TreeList<Chunk>* right() const { return _right; } |
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62 |
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63 // Wrapper on call to base class, to get the template to compile. |
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64 Chunk* head() const { return FreeList<Chunk>::head(); } |
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65 Chunk* tail() const { return FreeList<Chunk>::tail(); } |
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66 void set_head(Chunk* head) { FreeList<Chunk>::set_head(head); } |
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67 void set_tail(Chunk* tail) { FreeList<Chunk>::set_tail(tail); } |
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68 |
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69 size_t size() const { return FreeList<Chunk>::size(); } |
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70 |
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71 // Accessors for links in tree. |
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72 |
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73 void setLeft(TreeList<Chunk>* tl) { |
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74 _left = tl; |
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75 if (tl != NULL) |
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76 tl->setParent(this); |
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77 } |
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78 void setRight(TreeList<Chunk>* tl) { |
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79 _right = tl; |
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80 if (tl != NULL) |
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81 tl->setParent(this); |
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82 } |
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83 void setParent(TreeList<Chunk>* tl) { _parent = tl; } |
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84 |
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85 void clearLeft() { _left = NULL; } |
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86 void clearRight() { _right = NULL; } |
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87 void clearParent() { _parent = NULL; } |
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88 void initialize() { clearLeft(); clearRight(), clearParent(); } |
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89 |
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90 // For constructing a TreeList from a Tree chunk or |
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91 // address and size. |
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92 static TreeList<Chunk>* as_TreeList(TreeChunk<Chunk>* tc); |
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93 static TreeList<Chunk>* as_TreeList(HeapWord* addr, size_t size); |
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94 |
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95 // Returns the head of the free list as a pointer to a TreeChunk. |
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96 TreeChunk<Chunk>* head_as_TreeChunk(); |
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97 |
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98 // Returns the first available chunk in the free list as a pointer |
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99 // to a TreeChunk. |
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100 TreeChunk<Chunk>* first_available(); |
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101 |
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102 // Returns the block with the largest heap address amongst |
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103 // those in the list for this size; potentially slow and expensive, |
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104 // use with caution! |
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105 TreeChunk<Chunk>* largest_address(); |
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106 |
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107 // removeChunkReplaceIfNeeded() removes the given "tc" from the TreeList. |
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108 // If "tc" is the first chunk in the list, it is also the |
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109 // TreeList that is the node in the tree. removeChunkReplaceIfNeeded() |
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110 // returns the possibly replaced TreeList* for the node in |
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111 // the tree. It also updates the parent of the original |
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112 // node to point to the new node. |
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113 TreeList<Chunk>* removeChunkReplaceIfNeeded(TreeChunk<Chunk>* tc); |
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114 // See FreeList. |
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115 void returnChunkAtHead(TreeChunk<Chunk>* tc); |
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116 void returnChunkAtTail(TreeChunk<Chunk>* tc); |
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117 }; |
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118 |
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119 // A TreeChunk is a subclass of a Chunk that additionally |
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120 // maintains a pointer to the free list on which it is currently |
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121 // linked. |
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122 // A TreeChunk is also used as a node in the binary tree. This |
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123 // allows the binary tree to be maintained without any additional |
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124 // storage (the free chunks are used). In a binary tree the first |
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125 // chunk in the free list is also the tree node. Note that the |
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126 // TreeChunk has an embedded TreeList for this purpose. Because |
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127 // the first chunk in the list is distinguished in this fashion |
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128 // (also is the node in the tree), it is the last chunk to be found |
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129 // on the free list for a node in the tree and is only removed if |
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130 // it is the last chunk on the free list. |
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131 |
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132 template <class Chunk> |
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133 class TreeChunk : public Chunk { |
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134 friend class TreeList<Chunk>; |
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135 TreeList<Chunk>* _list; |
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136 TreeList<Chunk> _embedded_list; // if non-null, this chunk is on _list |
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137 protected: |
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138 TreeList<Chunk>* embedded_list() const { return (TreeList<Chunk>*) &_embedded_list; } |
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139 void set_embedded_list(TreeList<Chunk>* v) { _embedded_list = *v; } |
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140 public: |
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141 TreeList<Chunk>* list() { return _list; } |
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142 void set_list(TreeList<Chunk>* v) { _list = v; } |
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143 static TreeChunk<Chunk>* as_TreeChunk(Chunk* fc); |
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144 // Initialize fields in a TreeChunk that should be |
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145 // initialized when the TreeChunk is being added to |
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146 // a free list in the tree. |
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147 void initialize() { embedded_list()->initialize(); } |
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148 |
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149 Chunk* next() const { return Chunk::next(); } |
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150 Chunk* prev() const { return Chunk::prev(); } |
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151 size_t size() const volatile { return Chunk::size(); } |
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152 |
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153 // debugging |
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154 void verifyTreeChunkList() const; |
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155 }; |
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156 |
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157 |
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158 template <class Chunk> |
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159 class BinaryTreeDictionary: public FreeBlockDictionary<Chunk> { |
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160 friend class VMStructs; |
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161 bool _splay; |
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162 size_t _totalSize; |
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163 size_t _totalFreeBlocks; |
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164 TreeList<Chunk>* _root; |
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165 bool _adaptive_freelists; |
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166 |
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167 // private accessors |
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168 bool splay() const { return _splay; } |
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169 void set_splay(bool v) { _splay = v; } |
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170 void set_totalSize(size_t v) { _totalSize = v; } |
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171 virtual void inc_totalSize(size_t v); |
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172 virtual void dec_totalSize(size_t v); |
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173 size_t totalFreeBlocks() const { return _totalFreeBlocks; } |
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174 void set_totalFreeBlocks(size_t v) { _totalFreeBlocks = v; } |
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175 TreeList<Chunk>* root() const { return _root; } |
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176 void set_root(TreeList<Chunk>* v) { _root = v; } |
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177 bool adaptive_freelists() { return _adaptive_freelists; } |
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178 |
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179 // This field is added and can be set to point to the |
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180 // the Mutex used to synchronize access to the |
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181 // dictionary so that assertion checking can be done. |
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182 // For example it is set to point to _parDictionaryAllocLock. |
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183 NOT_PRODUCT(Mutex* _lock;) |
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184 |
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185 // Remove a chunk of size "size" or larger from the tree and |
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186 // return it. If the chunk |
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187 // is the last chunk of that size, remove the node for that size |
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188 // from the tree. |
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189 TreeChunk<Chunk>* getChunkFromTree(size_t size, enum FreeBlockDictionary<Chunk>::Dither dither, bool splay); |
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190 // Return a list of the specified size or NULL from the tree. |
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191 // The list is not removed from the tree. |
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192 TreeList<Chunk>* findList (size_t size) const; |
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193 // Remove this chunk from the tree. If the removal results |
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194 // in an empty list in the tree, remove the empty list. |
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195 TreeChunk<Chunk>* removeChunkFromTree(TreeChunk<Chunk>* tc); |
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196 // Remove the node in the trees starting at tl that has the |
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197 // minimum value and return it. Repair the tree as needed. |
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198 TreeList<Chunk>* removeTreeMinimum(TreeList<Chunk>* tl); |
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199 void semiSplayStep(TreeList<Chunk>* tl); |
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200 // Add this free chunk to the tree. |
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201 void insertChunkInTree(Chunk* freeChunk); |
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202 public: |
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203 |
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204 static const size_t min_tree_chunk_size = sizeof(TreeChunk<Chunk>)/HeapWordSize; |
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205 |
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206 void verifyTree() const; |
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207 // verify that the given chunk is in the tree. |
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208 bool verifyChunkInFreeLists(Chunk* tc) const; |
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209 private: |
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210 void verifyTreeHelper(TreeList<Chunk>* tl) const; |
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211 static size_t verifyPrevFreePtrs(TreeList<Chunk>* tl); |
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212 |
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213 // Returns the total number of chunks in the list. |
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214 size_t totalListLength(TreeList<Chunk>* tl) const; |
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215 // Returns the total number of words in the chunks in the tree |
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216 // starting at "tl". |
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217 size_t totalSizeInTree(TreeList<Chunk>* tl) const; |
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218 // Returns the sum of the square of the size of each block |
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219 // in the tree starting at "tl". |
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220 double sum_of_squared_block_sizes(TreeList<Chunk>* const tl) const; |
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221 // Returns the total number of free blocks in the tree starting |
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222 // at "tl". |
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223 size_t totalFreeBlocksInTree(TreeList<Chunk>* tl) const; |
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224 size_t numFreeBlocks() const; |
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225 size_t treeHeight() const; |
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226 size_t treeHeightHelper(TreeList<Chunk>* tl) const; |
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227 size_t totalNodesInTree(TreeList<Chunk>* tl) const; |
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228 size_t totalNodesHelper(TreeList<Chunk>* tl) const; |
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229 |
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230 public: |
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231 // Constructor |
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232 BinaryTreeDictionary(bool adaptive_freelists, bool splay = false); |
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233 BinaryTreeDictionary(MemRegion mr, bool adaptive_freelists, bool splay = false); |
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234 |
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235 // Public accessors |
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236 size_t totalSize() const { return _totalSize; } |
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237 |
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238 // Reset the dictionary to the initial conditions with |
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239 // a single free chunk. |
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240 void reset(MemRegion mr); |
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241 void reset(HeapWord* addr, size_t size); |
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242 // Reset the dictionary to be empty. |
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243 void reset(); |
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244 |
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245 // Return a chunk of size "size" or greater from |
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246 // the tree. |
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247 // want a better dynamic splay strategy for the future. |
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248 Chunk* getChunk(size_t size, enum FreeBlockDictionary<Chunk>::Dither dither) { |
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249 FreeBlockDictionary<Chunk>::verify_par_locked(); |
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250 Chunk* res = getChunkFromTree(size, dither, splay()); |
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251 assert(res == NULL || res->isFree(), |
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252 "Should be returning a free chunk"); |
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253 return res; |
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254 } |
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255 |
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256 void returnChunk(Chunk* chunk) { |
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257 FreeBlockDictionary<Chunk>::verify_par_locked(); |
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258 insertChunkInTree(chunk); |
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259 } |
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260 |
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261 void removeChunk(Chunk* chunk) { |
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262 FreeBlockDictionary<Chunk>::verify_par_locked(); |
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263 removeChunkFromTree((TreeChunk<Chunk>*)chunk); |
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264 assert(chunk->isFree(), "Should still be a free chunk"); |
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265 } |
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266 |
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267 size_t maxChunkSize() const; |
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268 size_t totalChunkSize(debug_only(const Mutex* lock)) const { |
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269 debug_only( |
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270 if (lock != NULL && lock->owned_by_self()) { |
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271 assert(totalSizeInTree(root()) == totalSize(), |
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272 "_totalSize inconsistency"); |
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273 } |
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274 ) |
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275 return totalSize(); |
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276 } |
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277 |
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278 size_t minSize() const { |
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279 return min_tree_chunk_size; |
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280 } |
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281 |
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282 double sum_of_squared_block_sizes() const { |
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283 return sum_of_squared_block_sizes(root()); |
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284 } |
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285 |
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286 Chunk* find_chunk_ends_at(HeapWord* target) const; |
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287 |
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288 // Find the list with size "size" in the binary tree and update |
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289 // the statistics in the list according to "split" (chunk was |
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290 // split or coalesce) and "birth" (chunk was added or removed). |
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291 void dictCensusUpdate(size_t size, bool split, bool birth); |
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292 // Return true if the dictionary is overpopulated (more chunks of |
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293 // this size than desired) for size "size". |
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294 bool coalDictOverPopulated(size_t size); |
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295 // Methods called at the beginning of a sweep to prepare the |
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296 // statistics for the sweep. |
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297 void beginSweepDictCensus(double coalSurplusPercent, |
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298 float inter_sweep_current, |
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299 float inter_sweep_estimate, |
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300 float intra_sweep_estimate); |
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301 // Methods called after the end of a sweep to modify the |
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302 // statistics for the sweep. |
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303 void endSweepDictCensus(double splitSurplusPercent); |
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304 // Return the largest free chunk in the tree. |
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305 Chunk* findLargestDict() const; |
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306 // Accessors for statistics |
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307 void setTreeSurplus(double splitSurplusPercent); |
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308 void setTreeHints(void); |
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309 // Reset statistics for all the lists in the tree. |
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310 void clearTreeCensus(void); |
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311 // Print the statistcis for all the lists in the tree. Also may |
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312 // print out summaries. |
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313 void printDictCensus(void) const; |
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314 void print_free_lists(outputStream* st) const; |
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315 |
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316 // For debugging. Returns the sum of the _returnedBytes for |
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317 // all lists in the tree. |
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318 size_t sumDictReturnedBytes() PRODUCT_RETURN0; |
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319 // Sets the _returnedBytes for all the lists in the tree to zero. |
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320 void initializeDictReturnedBytes() PRODUCT_RETURN; |
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321 // For debugging. Return the total number of chunks in the dictionary. |
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322 size_t totalCount() PRODUCT_RETURN0; |
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323 |
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324 void reportStatistics() const; |
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325 |
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326 void verify() const; |
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327 }; |
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328 |
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329 #endif // SHARE_VM_MEMORY_BINARYTREEDICTIONARY_HPP |