1 /* |
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2 * Copyright (c) 2001, 2013, 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_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP |
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26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP |
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27 |
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28 #include "gc_implementation/g1/g1BiasedArray.hpp" |
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29 #include "gc_implementation/g1/g1RegionToSpaceMapper.hpp" |
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30 #include "gc_implementation/g1/heapRegionSet.hpp" |
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31 |
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32 class HeapRegion; |
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33 class HeapRegionClosure; |
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34 class FreeRegionList; |
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35 |
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36 class G1HeapRegionTable : public G1BiasedMappedArray<HeapRegion*> { |
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37 protected: |
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38 virtual HeapRegion* default_value() const { return NULL; } |
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39 }; |
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40 |
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41 // This class keeps track of the actual heap memory, auxiliary data |
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42 // and its metadata (i.e., HeapRegion instances) and the list of free regions. |
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43 // |
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44 // This allows maximum flexibility for deciding what to commit or uncommit given |
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45 // a request from outside. |
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46 // |
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47 // HeapRegions are kept in the _regions array in address order. A region's |
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48 // index in the array corresponds to its index in the heap (i.e., 0 is the |
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49 // region at the bottom of the heap, 1 is the one after it, etc.). Two |
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50 // regions that are consecutive in the array should also be adjacent in the |
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51 // address space (i.e., region(i).end() == region(i+1).bottom(). |
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52 // |
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53 // We create a HeapRegion when we commit the region's address space |
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54 // for the first time. When we uncommit the address space of a |
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55 // region we retain the HeapRegion to be able to re-use it in the |
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56 // future (in case we recommit it). |
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57 // |
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58 // We keep track of three lengths: |
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59 // |
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60 // * _num_committed (returned by length()) is the number of currently |
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61 // committed regions. These may not be contiguous. |
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62 // * _allocated_heapregions_length (not exposed outside this class) is the |
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63 // number of regions+1 for which we have HeapRegions. |
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64 // * max_length() returns the maximum number of regions the heap can have. |
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65 // |
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66 |
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67 class HeapRegionSeq: public CHeapObj<mtGC> { |
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68 friend class VMStructs; |
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69 |
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70 G1HeapRegionTable _regions; |
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71 |
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72 G1RegionToSpaceMapper* _heap_mapper; |
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73 G1RegionToSpaceMapper* _prev_bitmap_mapper; |
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74 G1RegionToSpaceMapper* _next_bitmap_mapper; |
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75 G1RegionToSpaceMapper* _bot_mapper; |
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76 G1RegionToSpaceMapper* _cardtable_mapper; |
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77 G1RegionToSpaceMapper* _card_counts_mapper; |
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78 |
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79 FreeRegionList _free_list; |
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80 |
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81 // Each bit in this bitmap indicates that the corresponding region is available |
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82 // for allocation. |
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83 BitMap _available_map; |
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84 |
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85 // The number of regions committed in the heap. |
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86 uint _num_committed; |
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87 |
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88 // Internal only. The highest heap region +1 we allocated a HeapRegion instance for. |
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89 uint _allocated_heapregions_length; |
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90 |
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91 HeapWord* heap_bottom() const { return _regions.bottom_address_mapped(); } |
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92 HeapWord* heap_end() const {return _regions.end_address_mapped(); } |
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93 |
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94 void make_regions_available(uint index, uint num_regions = 1); |
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95 |
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96 // Pass down commit calls to the VirtualSpace. |
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97 void commit_regions(uint index, size_t num_regions = 1); |
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98 void uncommit_regions(uint index, size_t num_regions = 1); |
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99 |
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100 // Notify other data structures about change in the heap layout. |
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101 void update_committed_space(HeapWord* old_end, HeapWord* new_end); |
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102 // Calculate the starting region for each worker during parallel iteration so |
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103 // that they do not all start from the same region. |
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104 uint start_region_for_worker(uint worker_i, uint num_workers, uint num_regions) const; |
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105 |
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106 // Find a contiguous set of empty or uncommitted regions of length num and return |
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107 // the index of the first region or G1_NO_HRS_INDEX if the search was unsuccessful. |
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108 // If only_empty is true, only empty regions are considered. |
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109 // Searches from bottom to top of the heap, doing a first-fit. |
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110 uint find_contiguous(size_t num, bool only_empty); |
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111 // Finds the next sequence of unavailable regions starting from start_idx. Returns the |
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112 // length of the sequence found. If this result is zero, no such sequence could be found, |
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113 // otherwise res_idx indicates the start index of these regions. |
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114 uint find_unavailable_from_idx(uint start_idx, uint* res_idx) const; |
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115 // Finds the next sequence of empty regions starting from start_idx, going backwards in |
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116 // the heap. Returns the length of the sequence found. If this value is zero, no |
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117 // sequence could be found, otherwise res_idx contains the start index of this range. |
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118 uint find_empty_from_idx_reverse(uint start_idx, uint* res_idx) const; |
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119 // Allocate a new HeapRegion for the given index. |
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120 HeapRegion* new_heap_region(uint hrs_index); |
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121 #ifdef ASSERT |
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122 public: |
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123 bool is_free(HeapRegion* hr) const; |
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124 #endif |
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125 // Returns whether the given region is available for allocation. |
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126 bool is_available(uint region) const; |
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127 |
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128 public: |
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129 // Empty constructor, we'll initialize it with the initialize() method. |
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130 HeapRegionSeq() : _regions(), _heap_mapper(NULL), _num_committed(0), |
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131 _next_bitmap_mapper(NULL), _prev_bitmap_mapper(NULL), _bot_mapper(NULL), |
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132 _allocated_heapregions_length(0), _available_map(), |
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133 _free_list("Free list", new MasterFreeRegionListMtSafeChecker()) |
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134 { } |
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135 |
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136 void initialize(G1RegionToSpaceMapper* heap_storage, |
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137 G1RegionToSpaceMapper* prev_bitmap, |
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138 G1RegionToSpaceMapper* next_bitmap, |
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139 G1RegionToSpaceMapper* bot, |
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140 G1RegionToSpaceMapper* cardtable, |
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141 G1RegionToSpaceMapper* card_counts); |
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142 |
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143 // Return the "dummy" region used for G1AllocRegion. This is currently a hardwired |
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144 // new HeapRegion that owns HeapRegion at index 0. Since at the moment we commit |
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145 // the heap from the lowest address, this region (and its associated data |
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146 // structures) are available and we do not need to check further. |
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147 HeapRegion* get_dummy_region() { return new_heap_region(0); } |
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148 |
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149 // Return the HeapRegion at the given index. Assume that the index |
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150 // is valid. |
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151 inline HeapRegion* at(uint index) const; |
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152 |
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153 // If addr is within the committed space return its corresponding |
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154 // HeapRegion, otherwise return NULL. |
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155 inline HeapRegion* addr_to_region(HeapWord* addr) const; |
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156 |
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157 // Insert the given region into the free region list. |
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158 inline void insert_into_free_list(HeapRegion* hr); |
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159 |
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160 // Insert the given region list into the global free region list. |
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161 void insert_list_into_free_list(FreeRegionList* list) { |
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162 _free_list.add_ordered(list); |
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163 } |
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164 |
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165 HeapRegion* allocate_free_region(bool is_old) { |
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166 HeapRegion* hr = _free_list.remove_region(is_old); |
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167 |
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168 if (hr != NULL) { |
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169 assert(hr->next() == NULL, "Single region should not have next"); |
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170 assert(is_available(hr->hrs_index()), "Must be committed"); |
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171 } |
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172 return hr; |
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173 } |
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174 |
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175 inline void allocate_free_regions_starting_at(uint first, uint num_regions); |
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176 |
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177 // Remove all regions from the free list. |
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178 void remove_all_free_regions() { |
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179 _free_list.remove_all(); |
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180 } |
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181 |
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182 // Return the number of committed free regions in the heap. |
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183 uint num_free_regions() const { |
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184 return _free_list.length(); |
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185 } |
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186 |
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187 size_t total_capacity_bytes() const { |
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188 return num_free_regions() * HeapRegion::GrainBytes; |
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189 } |
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190 |
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191 // Return the number of available (uncommitted) regions. |
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192 uint available() const { return max_length() - length(); } |
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193 |
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194 // Return the number of regions that have been committed in the heap. |
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195 uint length() const { return _num_committed; } |
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196 |
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197 // Return the maximum number of regions in the heap. |
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198 uint max_length() const { return (uint)_regions.length(); } |
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199 |
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200 MemRegion reserved() const { return MemRegion(heap_bottom(), heap_end()); } |
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201 |
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202 // Expand the sequence to reflect that the heap has grown. Either create new |
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203 // HeapRegions, or re-use existing ones. Returns the number of regions the |
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204 // sequence was expanded by. If a HeapRegion allocation fails, the resulting |
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205 // number of regions might be smaller than what's desired. |
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206 uint expand_by(uint num_regions); |
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207 |
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208 // Makes sure that the regions from start to start+num_regions-1 are available |
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209 // for allocation. Returns the number of regions that were committed to achieve |
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210 // this. |
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211 uint expand_at(uint start, uint num_regions); |
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212 |
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213 // Find a contiguous set of empty regions of length num. Returns the start index of |
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214 // that set, or G1_NO_HRS_INDEX. |
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215 uint find_contiguous_only_empty(size_t num) { return find_contiguous(num, true); } |
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216 // Find a contiguous set of empty or unavailable regions of length num. Returns the |
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217 // start index of that set, or G1_NO_HRS_INDEX. |
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218 uint find_contiguous_empty_or_unavailable(size_t num) { return find_contiguous(num, false); } |
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219 |
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220 HeapRegion* next_region_in_heap(const HeapRegion* r) const; |
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221 |
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222 // Apply blk->doHeapRegion() on all committed regions in address order, |
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223 // terminating the iteration early if doHeapRegion() returns true. |
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224 void iterate(HeapRegionClosure* blk) const; |
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225 |
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226 void par_iterate(HeapRegionClosure* blk, uint worker_id, uint no_of_par_workers, jint claim_value) const; |
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227 |
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228 // Uncommit up to num_regions_to_remove regions that are completely free. |
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229 // Return the actual number of uncommitted regions. |
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230 uint shrink_by(uint num_regions_to_remove); |
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231 |
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232 void verify(); |
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233 |
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234 // Do some sanity checking. |
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235 void verify_optional() PRODUCT_RETURN; |
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236 }; |
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237 |
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238 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP |
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