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1 /* |
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2 * Copyright (c) 1997, 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 "classfile/systemDictionary.hpp" |
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27 #include "classfile/vmSymbols.hpp" |
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28 #include "gc_implementation/shared/liveRange.hpp" |
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29 #include "gc_implementation/shared/markSweep.hpp" |
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30 #include "gc_implementation/shared/spaceDecorator.hpp" |
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31 #include "memory/blockOffsetTable.inline.hpp" |
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32 #include "memory/defNewGeneration.hpp" |
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33 #include "memory/genCollectedHeap.hpp" |
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34 #include "memory/space.hpp" |
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35 #include "memory/space.inline.hpp" |
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36 #include "memory/universe.inline.hpp" |
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37 #include "oops/oop.inline.hpp" |
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38 #include "oops/oop.inline2.hpp" |
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39 #include "runtime/java.hpp" |
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40 #include "runtime/safepoint.hpp" |
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41 #include "utilities/copy.hpp" |
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42 #include "utilities/globalDefinitions.hpp" |
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43 #include "utilities/macros.hpp" |
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44 |
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45 void SpaceMemRegionOopsIterClosure::do_oop(oop* p) { SpaceMemRegionOopsIterClosure::do_oop_work(p); } |
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46 void SpaceMemRegionOopsIterClosure::do_oop(narrowOop* p) { SpaceMemRegionOopsIterClosure::do_oop_work(p); } |
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47 |
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48 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC |
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49 |
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50 HeapWord* DirtyCardToOopClosure::get_actual_top(HeapWord* top, |
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51 HeapWord* top_obj) { |
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52 if (top_obj != NULL) { |
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53 if (_sp->block_is_obj(top_obj)) { |
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54 if (_precision == CardTableModRefBS::ObjHeadPreciseArray) { |
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55 if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) { |
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56 // An arrayOop is starting on the dirty card - since we do exact |
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57 // store checks for objArrays we are done. |
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58 } else { |
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59 // Otherwise, it is possible that the object starting on the dirty |
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60 // card spans the entire card, and that the store happened on a |
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61 // later card. Figure out where the object ends. |
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62 // Use the block_size() method of the space over which |
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63 // the iteration is being done. That space (e.g. CMS) may have |
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64 // specific requirements on object sizes which will |
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65 // be reflected in the block_size() method. |
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66 top = top_obj + oop(top_obj)->size(); |
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67 } |
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68 } |
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69 } else { |
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70 top = top_obj; |
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71 } |
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72 } else { |
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73 assert(top == _sp->end(), "only case where top_obj == NULL"); |
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74 } |
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75 return top; |
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76 } |
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77 |
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78 void DirtyCardToOopClosure::walk_mem_region(MemRegion mr, |
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79 HeapWord* bottom, |
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80 HeapWord* top) { |
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81 // 1. Blocks may or may not be objects. |
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82 // 2. Even when a block_is_obj(), it may not entirely |
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83 // occupy the block if the block quantum is larger than |
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84 // the object size. |
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85 // We can and should try to optimize by calling the non-MemRegion |
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86 // version of oop_iterate() for all but the extremal objects |
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87 // (for which we need to call the MemRegion version of |
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88 // oop_iterate()) To be done post-beta XXX |
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89 for (; bottom < top; bottom += _sp->block_size(bottom)) { |
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90 // As in the case of contiguous space above, we'd like to |
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91 // just use the value returned by oop_iterate to increment the |
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92 // current pointer; unfortunately, that won't work in CMS because |
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93 // we'd need an interface change (it seems) to have the space |
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94 // "adjust the object size" (for instance pad it up to its |
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95 // block alignment or minimum block size restrictions. XXX |
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96 if (_sp->block_is_obj(bottom) && |
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97 !_sp->obj_allocated_since_save_marks(oop(bottom))) { |
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98 oop(bottom)->oop_iterate(_cl, mr); |
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99 } |
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100 } |
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101 } |
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102 |
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103 // We get called with "mr" representing the dirty region |
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104 // that we want to process. Because of imprecise marking, |
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105 // we may need to extend the incoming "mr" to the right, |
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106 // and scan more. However, because we may already have |
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107 // scanned some of that extended region, we may need to |
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108 // trim its right-end back some so we do not scan what |
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109 // we (or another worker thread) may already have scanned |
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110 // or planning to scan. |
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111 void DirtyCardToOopClosure::do_MemRegion(MemRegion mr) { |
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112 |
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113 // Some collectors need to do special things whenever their dirty |
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114 // cards are processed. For instance, CMS must remember mutator updates |
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115 // (i.e. dirty cards) so as to re-scan mutated objects. |
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116 // Such work can be piggy-backed here on dirty card scanning, so as to make |
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117 // it slightly more efficient than doing a complete non-detructive pre-scan |
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118 // of the card table. |
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119 MemRegionClosure* pCl = _sp->preconsumptionDirtyCardClosure(); |
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120 if (pCl != NULL) { |
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121 pCl->do_MemRegion(mr); |
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122 } |
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123 |
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124 HeapWord* bottom = mr.start(); |
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125 HeapWord* last = mr.last(); |
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126 HeapWord* top = mr.end(); |
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127 HeapWord* bottom_obj; |
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128 HeapWord* top_obj; |
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129 |
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130 assert(_precision == CardTableModRefBS::ObjHeadPreciseArray || |
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131 _precision == CardTableModRefBS::Precise, |
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132 "Only ones we deal with for now."); |
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133 |
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134 assert(_precision != CardTableModRefBS::ObjHeadPreciseArray || |
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135 _cl->idempotent() || _last_bottom == NULL || |
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136 top <= _last_bottom, |
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137 "Not decreasing"); |
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138 NOT_PRODUCT(_last_bottom = mr.start()); |
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139 |
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140 bottom_obj = _sp->block_start(bottom); |
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141 top_obj = _sp->block_start(last); |
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142 |
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143 assert(bottom_obj <= bottom, "just checking"); |
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144 assert(top_obj <= top, "just checking"); |
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145 |
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146 // Given what we think is the top of the memory region and |
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147 // the start of the object at the top, get the actual |
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148 // value of the top. |
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149 top = get_actual_top(top, top_obj); |
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150 |
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151 // If the previous call did some part of this region, don't redo. |
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152 if (_precision == CardTableModRefBS::ObjHeadPreciseArray && |
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153 _min_done != NULL && |
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154 _min_done < top) { |
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155 top = _min_done; |
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156 } |
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157 |
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158 // Top may have been reset, and in fact may be below bottom, |
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159 // e.g. the dirty card region is entirely in a now free object |
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160 // -- something that could happen with a concurrent sweeper. |
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161 bottom = MIN2(bottom, top); |
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162 MemRegion extended_mr = MemRegion(bottom, top); |
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163 assert(bottom <= top && |
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164 (_precision != CardTableModRefBS::ObjHeadPreciseArray || |
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165 _min_done == NULL || |
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166 top <= _min_done), |
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167 "overlap!"); |
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168 |
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169 // Walk the region if it is not empty; otherwise there is nothing to do. |
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170 if (!extended_mr.is_empty()) { |
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171 walk_mem_region(extended_mr, bottom_obj, top); |
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172 } |
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173 |
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174 // An idempotent closure might be applied in any order, so we don't |
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175 // record a _min_done for it. |
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176 if (!_cl->idempotent()) { |
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177 _min_done = bottom; |
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178 } else { |
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179 assert(_min_done == _last_explicit_min_done, |
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180 "Don't update _min_done for idempotent cl"); |
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181 } |
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182 } |
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183 |
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184 DirtyCardToOopClosure* Space::new_dcto_cl(ExtendedOopClosure* cl, |
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185 CardTableModRefBS::PrecisionStyle precision, |
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186 HeapWord* boundary) { |
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187 return new DirtyCardToOopClosure(this, cl, precision, boundary); |
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188 } |
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189 |
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190 HeapWord* ContiguousSpaceDCTOC::get_actual_top(HeapWord* top, |
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191 HeapWord* top_obj) { |
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192 if (top_obj != NULL && top_obj < (_sp->toContiguousSpace())->top()) { |
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193 if (_precision == CardTableModRefBS::ObjHeadPreciseArray) { |
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194 if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) { |
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195 // An arrayOop is starting on the dirty card - since we do exact |
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196 // store checks for objArrays we are done. |
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197 } else { |
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198 // Otherwise, it is possible that the object starting on the dirty |
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199 // card spans the entire card, and that the store happened on a |
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200 // later card. Figure out where the object ends. |
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201 assert(_sp->block_size(top_obj) == (size_t) oop(top_obj)->size(), |
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202 "Block size and object size mismatch"); |
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203 top = top_obj + oop(top_obj)->size(); |
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204 } |
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205 } |
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206 } else { |
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207 top = (_sp->toContiguousSpace())->top(); |
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208 } |
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209 return top; |
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210 } |
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211 |
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212 void Filtering_DCTOC::walk_mem_region(MemRegion mr, |
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213 HeapWord* bottom, |
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214 HeapWord* top) { |
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215 // Note that this assumption won't hold if we have a concurrent |
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216 // collector in this space, which may have freed up objects after |
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217 // they were dirtied and before the stop-the-world GC that is |
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218 // examining cards here. |
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219 assert(bottom < top, "ought to be at least one obj on a dirty card."); |
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220 |
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221 if (_boundary != NULL) { |
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222 // We have a boundary outside of which we don't want to look |
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223 // at objects, so create a filtering closure around the |
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224 // oop closure before walking the region. |
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225 FilteringClosure filter(_boundary, _cl); |
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226 walk_mem_region_with_cl(mr, bottom, top, &filter); |
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227 } else { |
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228 // No boundary, simply walk the heap with the oop closure. |
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229 walk_mem_region_with_cl(mr, bottom, top, _cl); |
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230 } |
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231 |
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232 } |
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233 |
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234 // We must replicate this so that the static type of "FilteringClosure" |
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235 // (see above) is apparent at the oop_iterate calls. |
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236 #define ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(ClosureType) \ |
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237 void ContiguousSpaceDCTOC::walk_mem_region_with_cl(MemRegion mr, \ |
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238 HeapWord* bottom, \ |
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239 HeapWord* top, \ |
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240 ClosureType* cl) { \ |
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241 bottom += oop(bottom)->oop_iterate(cl, mr); \ |
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242 if (bottom < top) { \ |
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243 HeapWord* next_obj = bottom + oop(bottom)->size(); \ |
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244 while (next_obj < top) { \ |
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245 /* Bottom lies entirely below top, so we can call the */ \ |
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246 /* non-memRegion version of oop_iterate below. */ \ |
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247 oop(bottom)->oop_iterate(cl); \ |
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248 bottom = next_obj; \ |
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249 next_obj = bottom + oop(bottom)->size(); \ |
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250 } \ |
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251 /* Last object. */ \ |
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252 oop(bottom)->oop_iterate(cl, mr); \ |
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253 } \ |
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254 } |
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255 |
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256 // (There are only two of these, rather than N, because the split is due |
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257 // only to the introduction of the FilteringClosure, a local part of the |
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258 // impl of this abstraction.) |
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259 ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(ExtendedOopClosure) |
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260 ContiguousSpaceDCTOC__walk_mem_region_with_cl_DEFN(FilteringClosure) |
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261 |
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262 DirtyCardToOopClosure* |
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263 ContiguousSpace::new_dcto_cl(ExtendedOopClosure* cl, |
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264 CardTableModRefBS::PrecisionStyle precision, |
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265 HeapWord* boundary) { |
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266 return new ContiguousSpaceDCTOC(this, cl, precision, boundary); |
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267 } |
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268 |
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269 void Space::initialize(MemRegion mr, |
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270 bool clear_space, |
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271 bool mangle_space) { |
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272 HeapWord* bottom = mr.start(); |
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273 HeapWord* end = mr.end(); |
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274 assert(Universe::on_page_boundary(bottom) && Universe::on_page_boundary(end), |
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275 "invalid space boundaries"); |
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276 set_bottom(bottom); |
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277 set_end(end); |
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278 if (clear_space) clear(mangle_space); |
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279 } |
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280 |
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281 void Space::clear(bool mangle_space) { |
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282 if (ZapUnusedHeapArea && mangle_space) { |
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283 mangle_unused_area(); |
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284 } |
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285 } |
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286 |
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287 ContiguousSpace::ContiguousSpace(): CompactibleSpace(), _top(NULL), |
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288 _concurrent_iteration_safe_limit(NULL) { |
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289 _mangler = new GenSpaceMangler(this); |
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290 } |
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291 |
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292 ContiguousSpace::~ContiguousSpace() { |
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293 delete _mangler; |
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294 } |
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295 |
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296 void ContiguousSpace::initialize(MemRegion mr, |
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297 bool clear_space, |
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298 bool mangle_space) |
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299 { |
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300 CompactibleSpace::initialize(mr, clear_space, mangle_space); |
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301 set_concurrent_iteration_safe_limit(top()); |
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302 } |
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303 |
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304 void ContiguousSpace::clear(bool mangle_space) { |
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305 set_top(bottom()); |
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306 set_saved_mark(); |
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307 CompactibleSpace::clear(mangle_space); |
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308 } |
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309 |
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310 bool ContiguousSpace::is_in(const void* p) const { |
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311 return _bottom <= p && p < _top; |
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312 } |
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313 |
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314 bool ContiguousSpace::is_free_block(const HeapWord* p) const { |
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315 return p >= _top; |
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316 } |
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317 |
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318 void OffsetTableContigSpace::clear(bool mangle_space) { |
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319 ContiguousSpace::clear(mangle_space); |
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320 _offsets.initialize_threshold(); |
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321 } |
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322 |
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323 void OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) { |
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324 Space::set_bottom(new_bottom); |
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325 _offsets.set_bottom(new_bottom); |
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326 } |
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327 |
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328 void OffsetTableContigSpace::set_end(HeapWord* new_end) { |
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329 // Space should not advertize an increase in size |
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330 // until after the underlying offest table has been enlarged. |
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331 _offsets.resize(pointer_delta(new_end, bottom())); |
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332 Space::set_end(new_end); |
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333 } |
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334 |
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335 #ifndef PRODUCT |
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336 |
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337 void ContiguousSpace::set_top_for_allocations(HeapWord* v) { |
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338 mangler()->set_top_for_allocations(v); |
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339 } |
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340 void ContiguousSpace::set_top_for_allocations() { |
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341 mangler()->set_top_for_allocations(top()); |
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342 } |
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343 void ContiguousSpace::check_mangled_unused_area(HeapWord* limit) { |
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344 mangler()->check_mangled_unused_area(limit); |
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345 } |
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346 |
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347 void ContiguousSpace::check_mangled_unused_area_complete() { |
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348 mangler()->check_mangled_unused_area_complete(); |
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349 } |
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350 |
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351 // Mangled only the unused space that has not previously |
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352 // been mangled and that has not been allocated since being |
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353 // mangled. |
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354 void ContiguousSpace::mangle_unused_area() { |
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355 mangler()->mangle_unused_area(); |
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356 } |
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357 void ContiguousSpace::mangle_unused_area_complete() { |
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358 mangler()->mangle_unused_area_complete(); |
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359 } |
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360 void ContiguousSpace::mangle_region(MemRegion mr) { |
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361 // Although this method uses SpaceMangler::mangle_region() which |
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362 // is not specific to a space, the when the ContiguousSpace version |
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363 // is called, it is always with regard to a space and this |
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364 // bounds checking is appropriate. |
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365 MemRegion space_mr(bottom(), end()); |
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366 assert(space_mr.contains(mr), "Mangling outside space"); |
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367 SpaceMangler::mangle_region(mr); |
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368 } |
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369 #endif // NOT_PRODUCT |
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370 |
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371 void CompactibleSpace::initialize(MemRegion mr, |
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372 bool clear_space, |
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373 bool mangle_space) { |
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374 Space::initialize(mr, clear_space, mangle_space); |
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375 set_compaction_top(bottom()); |
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376 _next_compaction_space = NULL; |
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377 } |
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378 |
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379 void CompactibleSpace::clear(bool mangle_space) { |
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380 Space::clear(mangle_space); |
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381 _compaction_top = bottom(); |
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382 } |
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383 |
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384 HeapWord* CompactibleSpace::forward(oop q, size_t size, |
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385 CompactPoint* cp, HeapWord* compact_top) { |
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386 // q is alive |
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387 // First check if we should switch compaction space |
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388 assert(this == cp->space, "'this' should be current compaction space."); |
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389 size_t compaction_max_size = pointer_delta(end(), compact_top); |
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390 while (size > compaction_max_size) { |
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391 // switch to next compaction space |
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392 cp->space->set_compaction_top(compact_top); |
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393 cp->space = cp->space->next_compaction_space(); |
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394 if (cp->space == NULL) { |
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395 cp->gen = GenCollectedHeap::heap()->prev_gen(cp->gen); |
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396 assert(cp->gen != NULL, "compaction must succeed"); |
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397 cp->space = cp->gen->first_compaction_space(); |
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398 assert(cp->space != NULL, "generation must have a first compaction space"); |
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399 } |
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400 compact_top = cp->space->bottom(); |
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401 cp->space->set_compaction_top(compact_top); |
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402 cp->threshold = cp->space->initialize_threshold(); |
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403 compaction_max_size = pointer_delta(cp->space->end(), compact_top); |
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404 } |
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405 |
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406 // store the forwarding pointer into the mark word |
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407 if ((HeapWord*)q != compact_top) { |
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408 q->forward_to(oop(compact_top)); |
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409 assert(q->is_gc_marked(), "encoding the pointer should preserve the mark"); |
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410 } else { |
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411 // if the object isn't moving we can just set the mark to the default |
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412 // mark and handle it specially later on. |
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413 q->init_mark(); |
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414 assert(q->forwardee() == NULL, "should be forwarded to NULL"); |
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415 } |
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416 |
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417 compact_top += size; |
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418 |
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419 // we need to update the offset table so that the beginnings of objects can be |
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420 // found during scavenge. Note that we are updating the offset table based on |
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421 // where the object will be once the compaction phase finishes. |
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422 if (compact_top > cp->threshold) |
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423 cp->threshold = |
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424 cp->space->cross_threshold(compact_top - size, compact_top); |
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425 return compact_top; |
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426 } |
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427 |
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428 |
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429 bool CompactibleSpace::insert_deadspace(size_t& allowed_deadspace_words, |
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430 HeapWord* q, size_t deadlength) { |
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431 if (allowed_deadspace_words >= deadlength) { |
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432 allowed_deadspace_words -= deadlength; |
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433 CollectedHeap::fill_with_object(q, deadlength); |
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434 oop(q)->set_mark(oop(q)->mark()->set_marked()); |
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435 assert((int) deadlength == oop(q)->size(), "bad filler object size"); |
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436 // Recall that we required "q == compaction_top". |
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437 return true; |
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438 } else { |
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439 allowed_deadspace_words = 0; |
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440 return false; |
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441 } |
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442 } |
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443 |
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444 #define block_is_always_obj(q) true |
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445 #define obj_size(q) oop(q)->size() |
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446 #define adjust_obj_size(s) s |
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447 |
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448 void CompactibleSpace::prepare_for_compaction(CompactPoint* cp) { |
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449 SCAN_AND_FORWARD(cp, end, block_is_obj, block_size); |
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450 } |
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451 |
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452 // Faster object search. |
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453 void ContiguousSpace::prepare_for_compaction(CompactPoint* cp) { |
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454 SCAN_AND_FORWARD(cp, top, block_is_always_obj, obj_size); |
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455 } |
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456 |
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457 void Space::adjust_pointers() { |
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458 // adjust all the interior pointers to point at the new locations of objects |
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459 // Used by MarkSweep::mark_sweep_phase3() |
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460 |
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461 // First check to see if there is any work to be done. |
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462 if (used() == 0) { |
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463 return; // Nothing to do. |
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464 } |
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465 |
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466 // Otherwise... |
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467 HeapWord* q = bottom(); |
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468 HeapWord* t = end(); |
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469 |
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470 debug_only(HeapWord* prev_q = NULL); |
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471 while (q < t) { |
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472 if (oop(q)->is_gc_marked()) { |
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473 // q is alive |
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474 |
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475 // point all the oops to the new location |
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476 size_t size = oop(q)->adjust_pointers(); |
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477 |
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478 debug_only(prev_q = q); |
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479 |
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480 q += size; |
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481 } else { |
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482 // q is not a live object. But we're not in a compactible space, |
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483 // So we don't have live ranges. |
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484 debug_only(prev_q = q); |
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485 q += block_size(q); |
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486 assert(q > prev_q, "we should be moving forward through memory"); |
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487 } |
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488 } |
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489 assert(q == t, "just checking"); |
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490 } |
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491 |
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492 void CompactibleSpace::adjust_pointers() { |
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493 // Check first is there is any work to do. |
|
494 if (used() == 0) { |
|
495 return; // Nothing to do. |
|
496 } |
|
497 |
|
498 SCAN_AND_ADJUST_POINTERS(adjust_obj_size); |
|
499 } |
|
500 |
|
501 void CompactibleSpace::compact() { |
|
502 SCAN_AND_COMPACT(obj_size); |
|
503 } |
|
504 |
|
505 void Space::print_short() const { print_short_on(tty); } |
|
506 |
|
507 void Space::print_short_on(outputStream* st) const { |
|
508 st->print(" space " SIZE_FORMAT "K, %3d%% used", capacity() / K, |
|
509 (int) ((double) used() * 100 / capacity())); |
|
510 } |
|
511 |
|
512 void Space::print() const { print_on(tty); } |
|
513 |
|
514 void Space::print_on(outputStream* st) const { |
|
515 print_short_on(st); |
|
516 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ")", |
|
517 bottom(), end()); |
|
518 } |
|
519 |
|
520 void ContiguousSpace::print_on(outputStream* st) const { |
|
521 print_short_on(st); |
|
522 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")", |
|
523 bottom(), top(), end()); |
|
524 } |
|
525 |
|
526 void OffsetTableContigSpace::print_on(outputStream* st) const { |
|
527 print_short_on(st); |
|
528 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " |
|
529 INTPTR_FORMAT ", " INTPTR_FORMAT ")", |
|
530 bottom(), top(), _offsets.threshold(), end()); |
|
531 } |
|
532 |
|
533 void ContiguousSpace::verify() const { |
|
534 HeapWord* p = bottom(); |
|
535 HeapWord* t = top(); |
|
536 HeapWord* prev_p = NULL; |
|
537 while (p < t) { |
|
538 oop(p)->verify(); |
|
539 prev_p = p; |
|
540 p += oop(p)->size(); |
|
541 } |
|
542 guarantee(p == top(), "end of last object must match end of space"); |
|
543 if (top() != end()) { |
|
544 guarantee(top() == block_start_const(end()-1) && |
|
545 top() == block_start_const(top()), |
|
546 "top should be start of unallocated block, if it exists"); |
|
547 } |
|
548 } |
|
549 |
|
550 void Space::oop_iterate(ExtendedOopClosure* blk) { |
|
551 ObjectToOopClosure blk2(blk); |
|
552 object_iterate(&blk2); |
|
553 } |
|
554 |
|
555 HeapWord* Space::object_iterate_careful(ObjectClosureCareful* cl) { |
|
556 guarantee(false, "NYI"); |
|
557 return bottom(); |
|
558 } |
|
559 |
|
560 HeapWord* Space::object_iterate_careful_m(MemRegion mr, |
|
561 ObjectClosureCareful* cl) { |
|
562 guarantee(false, "NYI"); |
|
563 return bottom(); |
|
564 } |
|
565 |
|
566 |
|
567 void Space::object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl) { |
|
568 assert(!mr.is_empty(), "Should be non-empty"); |
|
569 // We use MemRegion(bottom(), end()) rather than used_region() below |
|
570 // because the two are not necessarily equal for some kinds of |
|
571 // spaces, in particular, certain kinds of free list spaces. |
|
572 // We could use the more complicated but more precise: |
|
573 // MemRegion(used_region().start(), round_to(used_region().end(), CardSize)) |
|
574 // but the slight imprecision seems acceptable in the assertion check. |
|
575 assert(MemRegion(bottom(), end()).contains(mr), |
|
576 "Should be within used space"); |
|
577 HeapWord* prev = cl->previous(); // max address from last time |
|
578 if (prev >= mr.end()) { // nothing to do |
|
579 return; |
|
580 } |
|
581 // This assert will not work when we go from cms space to perm |
|
582 // space, and use same closure. Easy fix deferred for later. XXX YSR |
|
583 // assert(prev == NULL || contains(prev), "Should be within space"); |
|
584 |
|
585 bool last_was_obj_array = false; |
|
586 HeapWord *blk_start_addr, *region_start_addr; |
|
587 if (prev > mr.start()) { |
|
588 region_start_addr = prev; |
|
589 blk_start_addr = prev; |
|
590 // The previous invocation may have pushed "prev" beyond the |
|
591 // last allocated block yet there may be still be blocks |
|
592 // in this region due to a particular coalescing policy. |
|
593 // Relax the assertion so that the case where the unallocated |
|
594 // block is maintained and "prev" is beyond the unallocated |
|
595 // block does not cause the assertion to fire. |
|
596 assert((BlockOffsetArrayUseUnallocatedBlock && |
|
597 (!is_in(prev))) || |
|
598 (blk_start_addr == block_start(region_start_addr)), "invariant"); |
|
599 } else { |
|
600 region_start_addr = mr.start(); |
|
601 blk_start_addr = block_start(region_start_addr); |
|
602 } |
|
603 HeapWord* region_end_addr = mr.end(); |
|
604 MemRegion derived_mr(region_start_addr, region_end_addr); |
|
605 while (blk_start_addr < region_end_addr) { |
|
606 const size_t size = block_size(blk_start_addr); |
|
607 if (block_is_obj(blk_start_addr)) { |
|
608 last_was_obj_array = cl->do_object_bm(oop(blk_start_addr), derived_mr); |
|
609 } else { |
|
610 last_was_obj_array = false; |
|
611 } |
|
612 blk_start_addr += size; |
|
613 } |
|
614 if (!last_was_obj_array) { |
|
615 assert((bottom() <= blk_start_addr) && (blk_start_addr <= end()), |
|
616 "Should be within (closed) used space"); |
|
617 assert(blk_start_addr > prev, "Invariant"); |
|
618 cl->set_previous(blk_start_addr); // min address for next time |
|
619 } |
|
620 } |
|
621 |
|
622 bool Space::obj_is_alive(const HeapWord* p) const { |
|
623 assert (block_is_obj(p), "The address should point to an object"); |
|
624 return true; |
|
625 } |
|
626 |
|
627 void ContiguousSpace::object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl) { |
|
628 assert(!mr.is_empty(), "Should be non-empty"); |
|
629 assert(used_region().contains(mr), "Should be within used space"); |
|
630 HeapWord* prev = cl->previous(); // max address from last time |
|
631 if (prev >= mr.end()) { // nothing to do |
|
632 return; |
|
633 } |
|
634 // See comment above (in more general method above) in case you |
|
635 // happen to use this method. |
|
636 assert(prev == NULL || is_in_reserved(prev), "Should be within space"); |
|
637 |
|
638 bool last_was_obj_array = false; |
|
639 HeapWord *obj_start_addr, *region_start_addr; |
|
640 if (prev > mr.start()) { |
|
641 region_start_addr = prev; |
|
642 obj_start_addr = prev; |
|
643 assert(obj_start_addr == block_start(region_start_addr), "invariant"); |
|
644 } else { |
|
645 region_start_addr = mr.start(); |
|
646 obj_start_addr = block_start(region_start_addr); |
|
647 } |
|
648 HeapWord* region_end_addr = mr.end(); |
|
649 MemRegion derived_mr(region_start_addr, region_end_addr); |
|
650 while (obj_start_addr < region_end_addr) { |
|
651 oop obj = oop(obj_start_addr); |
|
652 const size_t size = obj->size(); |
|
653 last_was_obj_array = cl->do_object_bm(obj, derived_mr); |
|
654 obj_start_addr += size; |
|
655 } |
|
656 if (!last_was_obj_array) { |
|
657 assert((bottom() <= obj_start_addr) && (obj_start_addr <= end()), |
|
658 "Should be within (closed) used space"); |
|
659 assert(obj_start_addr > prev, "Invariant"); |
|
660 cl->set_previous(obj_start_addr); // min address for next time |
|
661 } |
|
662 } |
|
663 |
|
664 #if INCLUDE_ALL_GCS |
|
665 #define ContigSpace_PAR_OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \ |
|
666 \ |
|
667 void ContiguousSpace::par_oop_iterate(MemRegion mr, OopClosureType* blk) {\ |
|
668 HeapWord* obj_addr = mr.start(); \ |
|
669 HeapWord* t = mr.end(); \ |
|
670 while (obj_addr < t) { \ |
|
671 assert(oop(obj_addr)->is_oop(), "Should be an oop"); \ |
|
672 obj_addr += oop(obj_addr)->oop_iterate(blk); \ |
|
673 } \ |
|
674 } |
|
675 |
|
676 ALL_PAR_OOP_ITERATE_CLOSURES(ContigSpace_PAR_OOP_ITERATE_DEFN) |
|
677 |
|
678 #undef ContigSpace_PAR_OOP_ITERATE_DEFN |
|
679 #endif // INCLUDE_ALL_GCS |
|
680 |
|
681 void ContiguousSpace::oop_iterate(ExtendedOopClosure* blk) { |
|
682 if (is_empty()) return; |
|
683 HeapWord* obj_addr = bottom(); |
|
684 HeapWord* t = top(); |
|
685 // Could call objects iterate, but this is easier. |
|
686 while (obj_addr < t) { |
|
687 obj_addr += oop(obj_addr)->oop_iterate(blk); |
|
688 } |
|
689 } |
|
690 |
|
691 void ContiguousSpace::oop_iterate(MemRegion mr, ExtendedOopClosure* blk) { |
|
692 if (is_empty()) { |
|
693 return; |
|
694 } |
|
695 MemRegion cur = MemRegion(bottom(), top()); |
|
696 mr = mr.intersection(cur); |
|
697 if (mr.is_empty()) { |
|
698 return; |
|
699 } |
|
700 if (mr.equals(cur)) { |
|
701 oop_iterate(blk); |
|
702 return; |
|
703 } |
|
704 assert(mr.end() <= top(), "just took an intersection above"); |
|
705 HeapWord* obj_addr = block_start(mr.start()); |
|
706 HeapWord* t = mr.end(); |
|
707 |
|
708 // Handle first object specially. |
|
709 oop obj = oop(obj_addr); |
|
710 SpaceMemRegionOopsIterClosure smr_blk(blk, mr); |
|
711 obj_addr += obj->oop_iterate(&smr_blk); |
|
712 while (obj_addr < t) { |
|
713 oop obj = oop(obj_addr); |
|
714 assert(obj->is_oop(), "expected an oop"); |
|
715 obj_addr += obj->size(); |
|
716 // If "obj_addr" is not greater than top, then the |
|
717 // entire object "obj" is within the region. |
|
718 if (obj_addr <= t) { |
|
719 obj->oop_iterate(blk); |
|
720 } else { |
|
721 // "obj" extends beyond end of region |
|
722 obj->oop_iterate(&smr_blk); |
|
723 break; |
|
724 } |
|
725 }; |
|
726 } |
|
727 |
|
728 void ContiguousSpace::object_iterate(ObjectClosure* blk) { |
|
729 if (is_empty()) return; |
|
730 WaterMark bm = bottom_mark(); |
|
731 object_iterate_from(bm, blk); |
|
732 } |
|
733 |
|
734 // For a continguous space object_iterate() and safe_object_iterate() |
|
735 // are the same. |
|
736 void ContiguousSpace::safe_object_iterate(ObjectClosure* blk) { |
|
737 object_iterate(blk); |
|
738 } |
|
739 |
|
740 void ContiguousSpace::object_iterate_from(WaterMark mark, ObjectClosure* blk) { |
|
741 assert(mark.space() == this, "Mark does not match space"); |
|
742 HeapWord* p = mark.point(); |
|
743 while (p < top()) { |
|
744 blk->do_object(oop(p)); |
|
745 p += oop(p)->size(); |
|
746 } |
|
747 } |
|
748 |
|
749 HeapWord* |
|
750 ContiguousSpace::object_iterate_careful(ObjectClosureCareful* blk) { |
|
751 HeapWord * limit = concurrent_iteration_safe_limit(); |
|
752 assert(limit <= top(), "sanity check"); |
|
753 for (HeapWord* p = bottom(); p < limit;) { |
|
754 size_t size = blk->do_object_careful(oop(p)); |
|
755 if (size == 0) { |
|
756 return p; // failed at p |
|
757 } else { |
|
758 p += size; |
|
759 } |
|
760 } |
|
761 return NULL; // all done |
|
762 } |
|
763 |
|
764 #define ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \ |
|
765 \ |
|
766 void ContiguousSpace:: \ |
|
767 oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk) { \ |
|
768 HeapWord* t; \ |
|
769 HeapWord* p = saved_mark_word(); \ |
|
770 assert(p != NULL, "expected saved mark"); \ |
|
771 \ |
|
772 const intx interval = PrefetchScanIntervalInBytes; \ |
|
773 do { \ |
|
774 t = top(); \ |
|
775 while (p < t) { \ |
|
776 Prefetch::write(p, interval); \ |
|
777 debug_only(HeapWord* prev = p); \ |
|
778 oop m = oop(p); \ |
|
779 p += m->oop_iterate(blk); \ |
|
780 } \ |
|
781 } while (t < top()); \ |
|
782 \ |
|
783 set_saved_mark_word(p); \ |
|
784 } |
|
785 |
|
786 ALL_SINCE_SAVE_MARKS_CLOSURES(ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN) |
|
787 |
|
788 #undef ContigSpace_OOP_SINCE_SAVE_MARKS_DEFN |
|
789 |
|
790 // Very general, slow implementation. |
|
791 HeapWord* ContiguousSpace::block_start_const(const void* p) const { |
|
792 assert(MemRegion(bottom(), end()).contains(p), |
|
793 err_msg("p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")", |
|
794 p, bottom(), end())); |
|
795 if (p >= top()) { |
|
796 return top(); |
|
797 } else { |
|
798 HeapWord* last = bottom(); |
|
799 HeapWord* cur = last; |
|
800 while (cur <= p) { |
|
801 last = cur; |
|
802 cur += oop(cur)->size(); |
|
803 } |
|
804 assert(oop(last)->is_oop(), |
|
805 err_msg(PTR_FORMAT " should be an object start", last)); |
|
806 return last; |
|
807 } |
|
808 } |
|
809 |
|
810 size_t ContiguousSpace::block_size(const HeapWord* p) const { |
|
811 assert(MemRegion(bottom(), end()).contains(p), |
|
812 err_msg("p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")", |
|
813 p, bottom(), end())); |
|
814 HeapWord* current_top = top(); |
|
815 assert(p <= current_top, |
|
816 err_msg("p > current top - p: " PTR_FORMAT ", current top: " PTR_FORMAT, |
|
817 p, current_top)); |
|
818 assert(p == current_top || oop(p)->is_oop(), |
|
819 err_msg("p (" PTR_FORMAT ") is not a block start - " |
|
820 "current_top: " PTR_FORMAT ", is_oop: %s", |
|
821 p, current_top, BOOL_TO_STR(oop(p)->is_oop()))); |
|
822 if (p < current_top) { |
|
823 return oop(p)->size(); |
|
824 } else { |
|
825 assert(p == current_top, "just checking"); |
|
826 return pointer_delta(end(), (HeapWord*) p); |
|
827 } |
|
828 } |
|
829 |
|
830 // This version requires locking. |
|
831 inline HeapWord* ContiguousSpace::allocate_impl(size_t size, |
|
832 HeapWord* const end_value) { |
|
833 // In G1 there are places where a GC worker can allocates into a |
|
834 // region using this serial allocation code without being prone to a |
|
835 // race with other GC workers (we ensure that no other GC worker can |
|
836 // access the same region at the same time). So the assert below is |
|
837 // too strong in the case of G1. |
|
838 assert(Heap_lock->owned_by_self() || |
|
839 (SafepointSynchronize::is_at_safepoint() && |
|
840 (Thread::current()->is_VM_thread() || UseG1GC)), |
|
841 "not locked"); |
|
842 HeapWord* obj = top(); |
|
843 if (pointer_delta(end_value, obj) >= size) { |
|
844 HeapWord* new_top = obj + size; |
|
845 set_top(new_top); |
|
846 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment"); |
|
847 return obj; |
|
848 } else { |
|
849 return NULL; |
|
850 } |
|
851 } |
|
852 |
|
853 // This version is lock-free. |
|
854 inline HeapWord* ContiguousSpace::par_allocate_impl(size_t size, |
|
855 HeapWord* const end_value) { |
|
856 do { |
|
857 HeapWord* obj = top(); |
|
858 if (pointer_delta(end_value, obj) >= size) { |
|
859 HeapWord* new_top = obj + size; |
|
860 HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj); |
|
861 // result can be one of two: |
|
862 // the old top value: the exchange succeeded |
|
863 // otherwise: the new value of the top is returned. |
|
864 if (result == obj) { |
|
865 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment"); |
|
866 return obj; |
|
867 } |
|
868 } else { |
|
869 return NULL; |
|
870 } |
|
871 } while (true); |
|
872 } |
|
873 |
|
874 // Requires locking. |
|
875 HeapWord* ContiguousSpace::allocate(size_t size) { |
|
876 return allocate_impl(size, end()); |
|
877 } |
|
878 |
|
879 // Lock-free. |
|
880 HeapWord* ContiguousSpace::par_allocate(size_t size) { |
|
881 return par_allocate_impl(size, end()); |
|
882 } |
|
883 |
|
884 void ContiguousSpace::allocate_temporary_filler(int factor) { |
|
885 // allocate temporary type array decreasing free size with factor 'factor' |
|
886 assert(factor >= 0, "just checking"); |
|
887 size_t size = pointer_delta(end(), top()); |
|
888 |
|
889 // if space is full, return |
|
890 if (size == 0) return; |
|
891 |
|
892 if (factor > 0) { |
|
893 size -= size/factor; |
|
894 } |
|
895 size = align_object_size(size); |
|
896 |
|
897 const size_t array_header_size = typeArrayOopDesc::header_size(T_INT); |
|
898 if (size >= (size_t)align_object_size(array_header_size)) { |
|
899 size_t length = (size - array_header_size) * (HeapWordSize / sizeof(jint)); |
|
900 // allocate uninitialized int array |
|
901 typeArrayOop t = (typeArrayOop) allocate(size); |
|
902 assert(t != NULL, "allocation should succeed"); |
|
903 t->set_mark(markOopDesc::prototype()); |
|
904 t->set_klass(Universe::intArrayKlassObj()); |
|
905 t->set_length((int)length); |
|
906 } else { |
|
907 assert(size == CollectedHeap::min_fill_size(), |
|
908 "size for smallest fake object doesn't match"); |
|
909 instanceOop obj = (instanceOop) allocate(size); |
|
910 obj->set_mark(markOopDesc::prototype()); |
|
911 obj->set_klass_gap(0); |
|
912 obj->set_klass(SystemDictionary::Object_klass()); |
|
913 } |
|
914 } |
|
915 |
|
916 void EdenSpace::clear(bool mangle_space) { |
|
917 ContiguousSpace::clear(mangle_space); |
|
918 set_soft_end(end()); |
|
919 } |
|
920 |
|
921 // Requires locking. |
|
922 HeapWord* EdenSpace::allocate(size_t size) { |
|
923 return allocate_impl(size, soft_end()); |
|
924 } |
|
925 |
|
926 // Lock-free. |
|
927 HeapWord* EdenSpace::par_allocate(size_t size) { |
|
928 return par_allocate_impl(size, soft_end()); |
|
929 } |
|
930 |
|
931 HeapWord* ConcEdenSpace::par_allocate(size_t size) |
|
932 { |
|
933 do { |
|
934 // The invariant is top() should be read before end() because |
|
935 // top() can't be greater than end(), so if an update of _soft_end |
|
936 // occurs between 'end_val = end();' and 'top_val = top();' top() |
|
937 // also can grow up to the new end() and the condition |
|
938 // 'top_val > end_val' is true. To ensure the loading order |
|
939 // OrderAccess::loadload() is required after top() read. |
|
940 HeapWord* obj = top(); |
|
941 OrderAccess::loadload(); |
|
942 if (pointer_delta(*soft_end_addr(), obj) >= size) { |
|
943 HeapWord* new_top = obj + size; |
|
944 HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj); |
|
945 // result can be one of two: |
|
946 // the old top value: the exchange succeeded |
|
947 // otherwise: the new value of the top is returned. |
|
948 if (result == obj) { |
|
949 assert(is_aligned(obj) && is_aligned(new_top), "checking alignment"); |
|
950 return obj; |
|
951 } |
|
952 } else { |
|
953 return NULL; |
|
954 } |
|
955 } while (true); |
|
956 } |
|
957 |
|
958 |
|
959 HeapWord* OffsetTableContigSpace::initialize_threshold() { |
|
960 return _offsets.initialize_threshold(); |
|
961 } |
|
962 |
|
963 HeapWord* OffsetTableContigSpace::cross_threshold(HeapWord* start, HeapWord* end) { |
|
964 _offsets.alloc_block(start, end); |
|
965 return _offsets.threshold(); |
|
966 } |
|
967 |
|
968 OffsetTableContigSpace::OffsetTableContigSpace(BlockOffsetSharedArray* sharedOffsetArray, |
|
969 MemRegion mr) : |
|
970 _offsets(sharedOffsetArray, mr), |
|
971 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true) |
|
972 { |
|
973 _offsets.set_contig_space(this); |
|
974 initialize(mr, SpaceDecorator::Clear, SpaceDecorator::Mangle); |
|
975 } |
|
976 |
|
977 #define OBJ_SAMPLE_INTERVAL 0 |
|
978 #define BLOCK_SAMPLE_INTERVAL 100 |
|
979 |
|
980 void OffsetTableContigSpace::verify() const { |
|
981 HeapWord* p = bottom(); |
|
982 HeapWord* prev_p = NULL; |
|
983 int objs = 0; |
|
984 int blocks = 0; |
|
985 |
|
986 if (VerifyObjectStartArray) { |
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987 _offsets.verify(); |
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988 } |
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989 |
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990 while (p < top()) { |
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991 size_t size = oop(p)->size(); |
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992 // For a sampling of objects in the space, find it using the |
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993 // block offset table. |
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994 if (blocks == BLOCK_SAMPLE_INTERVAL) { |
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995 guarantee(p == block_start_const(p + (size/2)), |
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996 "check offset computation"); |
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997 blocks = 0; |
|
998 } else { |
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999 blocks++; |
|
1000 } |
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1001 |
|
1002 if (objs == OBJ_SAMPLE_INTERVAL) { |
|
1003 oop(p)->verify(); |
|
1004 objs = 0; |
|
1005 } else { |
|
1006 objs++; |
|
1007 } |
|
1008 prev_p = p; |
|
1009 p += size; |
|
1010 } |
|
1011 guarantee(p == top(), "end of last object must match end of space"); |
|
1012 } |
|
1013 |
|
1014 |
|
1015 size_t TenuredSpace::allowed_dead_ratio() const { |
|
1016 return MarkSweepDeadRatio; |
|
1017 } |