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1 /* |
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2 * Copyright (c) 2001, 2014, 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 #include "precompiled.hpp" |
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26 #include "memory/freeBlockDictionary.hpp" |
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27 #include "memory/freeList.hpp" |
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28 #include "memory/metachunk.hpp" |
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29 #include "memory/sharedHeap.hpp" |
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30 #include "runtime/globals.hpp" |
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31 #include "runtime/mutex.hpp" |
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32 #include "runtime/vmThread.hpp" |
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33 #include "utilities/macros.hpp" |
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34 |
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35 #if INCLUDE_ALL_GCS |
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36 #include "gc_implementation/concurrentMarkSweep/freeChunk.hpp" |
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37 #include "gc_implementation/g1/g1CodeCacheRemSet.hpp" |
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38 #endif // INCLUDE_ALL_GCS |
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39 |
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40 // Free list. A FreeList is used to access a linked list of chunks |
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41 // of space in the heap. The head and tail are maintained so that |
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42 // items can be (as in the current implementation) added at the |
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43 // at the tail of the list and removed from the head of the list to |
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44 // maintain a FIFO queue. |
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45 |
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46 template <class Chunk> |
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47 FreeList<Chunk>::FreeList() : |
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48 _head(NULL), _tail(NULL) |
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49 #ifdef ASSERT |
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50 , _protecting_lock(NULL) |
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51 #endif |
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52 { |
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53 _size = 0; |
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54 _count = 0; |
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55 } |
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56 |
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57 template <class Chunk> |
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58 void FreeList<Chunk>::link_head(Chunk* v) { |
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59 assert_proper_lock_protection(); |
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60 set_head(v); |
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61 // If this method is not used (just set the head instead), |
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62 // this check can be avoided. |
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63 if (v != NULL) { |
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64 v->link_prev(NULL); |
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65 } |
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66 } |
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67 |
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68 |
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69 |
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70 template <class Chunk> |
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71 void FreeList<Chunk>::reset() { |
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72 // Don't set the _size to 0 because this method is |
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73 // used with a existing list that has a size but which has |
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74 // been emptied. |
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75 // Don't clear the _protecting_lock of an existing list. |
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76 set_count(0); |
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77 set_head(NULL); |
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78 set_tail(NULL); |
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79 } |
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80 |
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81 template <class Chunk> |
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82 void FreeList<Chunk>::initialize() { |
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83 #ifdef ASSERT |
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84 // Needed early because it might be checked in other initializing code. |
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85 set_protecting_lock(NULL); |
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86 #endif |
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87 reset(); |
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88 set_size(0); |
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89 } |
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90 |
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91 template <class Chunk_t> |
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92 Chunk_t* FreeList<Chunk_t>::get_chunk_at_head() { |
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93 assert_proper_lock_protection(); |
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94 assert(head() == NULL || head()->prev() == NULL, "list invariant"); |
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95 assert(tail() == NULL || tail()->next() == NULL, "list invariant"); |
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96 Chunk_t* fc = head(); |
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97 if (fc != NULL) { |
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98 Chunk_t* nextFC = fc->next(); |
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99 if (nextFC != NULL) { |
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100 // The chunk fc being removed has a "next". Set the "next" to the |
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101 // "prev" of fc. |
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102 nextFC->link_prev(NULL); |
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103 } else { // removed tail of list |
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104 link_tail(NULL); |
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105 } |
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106 link_head(nextFC); |
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107 decrement_count(); |
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108 } |
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109 assert(head() == NULL || head()->prev() == NULL, "list invariant"); |
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110 assert(tail() == NULL || tail()->next() == NULL, "list invariant"); |
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111 return fc; |
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112 } |
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113 |
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114 |
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115 template <class Chunk> |
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116 void FreeList<Chunk>::getFirstNChunksFromList(size_t n, FreeList<Chunk>* fl) { |
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117 assert_proper_lock_protection(); |
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118 assert(fl->count() == 0, "Precondition"); |
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119 if (count() > 0) { |
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120 int k = 1; |
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121 fl->set_head(head()); n--; |
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122 Chunk* tl = head(); |
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123 while (tl->next() != NULL && n > 0) { |
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124 tl = tl->next(); n--; k++; |
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125 } |
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126 assert(tl != NULL, "Loop Inv."); |
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127 |
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128 // First, fix up the list we took from. |
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129 Chunk* new_head = tl->next(); |
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130 set_head(new_head); |
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131 set_count(count() - k); |
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132 if (new_head == NULL) { |
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133 set_tail(NULL); |
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134 } else { |
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135 new_head->link_prev(NULL); |
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136 } |
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137 // Now we can fix up the tail. |
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138 tl->link_next(NULL); |
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139 // And return the result. |
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140 fl->set_tail(tl); |
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141 fl->set_count(k); |
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142 } |
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143 } |
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144 |
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145 // Remove this chunk from the list |
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146 template <class Chunk> |
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147 void FreeList<Chunk>::remove_chunk(Chunk*fc) { |
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148 assert_proper_lock_protection(); |
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149 assert(head() != NULL, "Remove from empty list"); |
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150 assert(fc != NULL, "Remove a NULL chunk"); |
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151 assert(size() == fc->size(), "Wrong list"); |
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152 assert(head() == NULL || head()->prev() == NULL, "list invariant"); |
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153 assert(tail() == NULL || tail()->next() == NULL, "list invariant"); |
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154 |
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155 Chunk* prevFC = fc->prev(); |
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156 Chunk* nextFC = fc->next(); |
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157 if (nextFC != NULL) { |
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158 // The chunk fc being removed has a "next". Set the "next" to the |
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159 // "prev" of fc. |
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160 nextFC->link_prev(prevFC); |
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161 } else { // removed tail of list |
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162 link_tail(prevFC); |
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163 } |
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164 if (prevFC == NULL) { // removed head of list |
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165 link_head(nextFC); |
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166 assert(nextFC == NULL || nextFC->prev() == NULL, |
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167 "Prev of head should be NULL"); |
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168 } else { |
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169 prevFC->link_next(nextFC); |
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170 assert(tail() != prevFC || prevFC->next() == NULL, |
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171 "Next of tail should be NULL"); |
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172 } |
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173 decrement_count(); |
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174 assert(((head() == NULL) + (tail() == NULL) + (count() == 0)) % 3 == 0, |
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175 "H/T/C Inconsistency"); |
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176 // clear next and prev fields of fc, debug only |
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177 NOT_PRODUCT( |
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178 fc->link_prev(NULL); |
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179 fc->link_next(NULL); |
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180 ) |
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181 assert(fc->is_free(), "Should still be a free chunk"); |
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182 assert(head() == NULL || head()->prev() == NULL, "list invariant"); |
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183 assert(tail() == NULL || tail()->next() == NULL, "list invariant"); |
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184 assert(head() == NULL || head()->size() == size(), "wrong item on list"); |
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185 assert(tail() == NULL || tail()->size() == size(), "wrong item on list"); |
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186 } |
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187 |
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188 // Add this chunk at the head of the list. |
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189 template <class Chunk> |
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190 void FreeList<Chunk>::return_chunk_at_head(Chunk* chunk, bool record_return) { |
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191 assert_proper_lock_protection(); |
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192 assert(chunk != NULL, "insert a NULL chunk"); |
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193 assert(size() == chunk->size(), "Wrong size"); |
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194 assert(head() == NULL || head()->prev() == NULL, "list invariant"); |
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195 assert(tail() == NULL || tail()->next() == NULL, "list invariant"); |
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196 |
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197 Chunk* oldHead = head(); |
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198 assert(chunk != oldHead, "double insertion"); |
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199 chunk->link_after(oldHead); |
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200 link_head(chunk); |
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201 if (oldHead == NULL) { // only chunk in list |
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202 assert(tail() == NULL, "inconsistent FreeList"); |
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203 link_tail(chunk); |
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204 } |
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205 increment_count(); // of # of chunks in list |
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206 assert(head() == NULL || head()->prev() == NULL, "list invariant"); |
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207 assert(tail() == NULL || tail()->next() == NULL, "list invariant"); |
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208 assert(head() == NULL || head()->size() == size(), "wrong item on list"); |
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209 assert(tail() == NULL || tail()->size() == size(), "wrong item on list"); |
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210 } |
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211 |
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212 template <class Chunk> |
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213 void FreeList<Chunk>::return_chunk_at_head(Chunk* chunk) { |
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214 assert_proper_lock_protection(); |
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215 return_chunk_at_head(chunk, true); |
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216 } |
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217 |
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218 // Add this chunk at the tail of the list. |
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219 template <class Chunk> |
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220 void FreeList<Chunk>::return_chunk_at_tail(Chunk* chunk, bool record_return) { |
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221 assert_proper_lock_protection(); |
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222 assert(head() == NULL || head()->prev() == NULL, "list invariant"); |
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223 assert(tail() == NULL || tail()->next() == NULL, "list invariant"); |
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224 assert(chunk != NULL, "insert a NULL chunk"); |
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225 assert(size() == chunk->size(), "wrong size"); |
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226 |
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227 Chunk* oldTail = tail(); |
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228 assert(chunk != oldTail, "double insertion"); |
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229 if (oldTail != NULL) { |
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230 oldTail->link_after(chunk); |
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231 } else { // only chunk in list |
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232 assert(head() == NULL, "inconsistent FreeList"); |
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233 link_head(chunk); |
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234 } |
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235 link_tail(chunk); |
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236 increment_count(); // of # of chunks in list |
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237 assert(head() == NULL || head()->prev() == NULL, "list invariant"); |
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238 assert(tail() == NULL || tail()->next() == NULL, "list invariant"); |
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239 assert(head() == NULL || head()->size() == size(), "wrong item on list"); |
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240 assert(tail() == NULL || tail()->size() == size(), "wrong item on list"); |
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241 } |
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242 |
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243 template <class Chunk> |
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244 void FreeList<Chunk>::return_chunk_at_tail(Chunk* chunk) { |
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245 return_chunk_at_tail(chunk, true); |
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246 } |
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247 |
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248 template <class Chunk> |
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249 void FreeList<Chunk>::prepend(FreeList<Chunk>* fl) { |
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250 assert_proper_lock_protection(); |
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251 if (fl->count() > 0) { |
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252 if (count() == 0) { |
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253 set_head(fl->head()); |
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254 set_tail(fl->tail()); |
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255 set_count(fl->count()); |
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256 } else { |
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257 // Both are non-empty. |
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258 Chunk* fl_tail = fl->tail(); |
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259 Chunk* this_head = head(); |
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260 assert(fl_tail->next() == NULL, "Well-formedness of fl"); |
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261 fl_tail->link_next(this_head); |
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262 this_head->link_prev(fl_tail); |
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263 set_head(fl->head()); |
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264 set_count(count() + fl->count()); |
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265 } |
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266 fl->set_head(NULL); |
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267 fl->set_tail(NULL); |
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268 fl->set_count(0); |
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269 } |
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270 } |
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271 |
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272 // verify_chunk_in_free_lists() is used to verify that an item is in this free list. |
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273 // It is used as a debugging aid. |
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274 template <class Chunk> |
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275 bool FreeList<Chunk>::verify_chunk_in_free_list(Chunk* fc) const { |
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276 // This is an internal consistency check, not part of the check that the |
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277 // chunk is in the free lists. |
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278 guarantee(fc->size() == size(), "Wrong list is being searched"); |
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279 Chunk* curFC = head(); |
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280 while (curFC) { |
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281 // This is an internal consistency check. |
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282 guarantee(size() == curFC->size(), "Chunk is in wrong list."); |
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283 if (fc == curFC) { |
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284 return true; |
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285 } |
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286 curFC = curFC->next(); |
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287 } |
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288 return false; |
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289 } |
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290 |
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291 #ifndef PRODUCT |
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292 template <class Chunk> |
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293 void FreeList<Chunk>::assert_proper_lock_protection_work() const { |
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294 assert(protecting_lock() != NULL, "Don't call this directly"); |
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295 assert(ParallelGCThreads > 0, "Don't call this directly"); |
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296 Thread* thr = Thread::current(); |
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297 if (thr->is_VM_thread() || thr->is_ConcurrentGC_thread()) { |
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298 // assert that we are holding the freelist lock |
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299 } else if (thr->is_GC_task_thread()) { |
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300 assert(protecting_lock()->owned_by_self(), "FreeList RACE DETECTED"); |
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301 } else if (thr->is_Java_thread()) { |
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302 assert(!SafepointSynchronize::is_at_safepoint(), "Should not be executing"); |
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303 } else { |
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304 ShouldNotReachHere(); // unaccounted thread type? |
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305 } |
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306 } |
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307 #endif |
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308 |
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309 // Print the "label line" for free list stats. |
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310 template <class Chunk> |
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311 void FreeList<Chunk>::print_labels_on(outputStream* st, const char* c) { |
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312 st->print("%16s\t", c); |
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313 st->print("%14s\t" "%14s\t" "%14s\t" "%14s\t" "%14s\t" |
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314 "%14s\t" "%14s\t" "%14s\t" "%14s\t" "%14s\t" "\n", |
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315 "bfrsurp", "surplus", "desired", "prvSwep", "bfrSwep", |
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316 "count", "cBirths", "cDeaths", "sBirths", "sDeaths"); |
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317 } |
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318 |
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319 // Print the AllocationStats for the given free list. If the second argument |
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320 // to the call is a non-null string, it is printed in the first column; |
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321 // otherwise, if the argument is null (the default), then the size of the |
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322 // (free list) block is printed in the first column. |
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323 template <class Chunk_t> |
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324 void FreeList<Chunk_t>::print_on(outputStream* st, const char* c) const { |
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325 if (c != NULL) { |
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326 st->print("%16s", c); |
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327 } else { |
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328 st->print(SIZE_FORMAT_W(16), size()); |
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329 } |
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330 } |
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331 |
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332 template class FreeList<Metablock>; |
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333 template class FreeList<Metachunk>; |
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334 #if INCLUDE_ALL_GCS |
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335 template class FreeList<FreeChunk>; |
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336 template class FreeList<G1CodeRootChunk>; |
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337 #endif // INCLUDE_ALL_GCS |