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1 /*
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2 * Copyright 1997-2005 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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20 * CA 95054 USA or visit www.sun.com if you need additional information or
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21 * have any questions.
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22 *
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23 */
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24
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25 #include "incls/_precompiled.incl"
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26 #include "incls/_markSweep.cpp.incl"
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27
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28 GrowableArray<oop>* MarkSweep::_marking_stack = NULL;
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29 GrowableArray<Klass*>* MarkSweep::_revisit_klass_stack = NULL;
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30
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31 GrowableArray<oop>* MarkSweep::_preserved_oop_stack = NULL;
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32 GrowableArray<markOop>* MarkSweep::_preserved_mark_stack= NULL;
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33 size_t MarkSweep::_preserved_count = 0;
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34 size_t MarkSweep::_preserved_count_max = 0;
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35 PreservedMark* MarkSweep::_preserved_marks = NULL;
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36 ReferenceProcessor* MarkSweep::_ref_processor = NULL;
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37
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38 #ifdef VALIDATE_MARK_SWEEP
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39 GrowableArray<oop*>* MarkSweep::_root_refs_stack = NULL;
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40 GrowableArray<oop> * MarkSweep::_live_oops = NULL;
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41 GrowableArray<oop> * MarkSweep::_live_oops_moved_to = NULL;
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42 GrowableArray<size_t>* MarkSweep::_live_oops_size = NULL;
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43 size_t MarkSweep::_live_oops_index = 0;
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44 size_t MarkSweep::_live_oops_index_at_perm = 0;
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45 GrowableArray<oop*>* MarkSweep::_other_refs_stack = NULL;
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46 GrowableArray<oop*>* MarkSweep::_adjusted_pointers = NULL;
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47 bool MarkSweep::_pointer_tracking = false;
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48 bool MarkSweep::_root_tracking = true;
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49
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50 GrowableArray<HeapWord*>* MarkSweep::_cur_gc_live_oops = NULL;
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51 GrowableArray<HeapWord*>* MarkSweep::_cur_gc_live_oops_moved_to = NULL;
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52 GrowableArray<size_t> * MarkSweep::_cur_gc_live_oops_size = NULL;
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53 GrowableArray<HeapWord*>* MarkSweep::_last_gc_live_oops = NULL;
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54 GrowableArray<HeapWord*>* MarkSweep::_last_gc_live_oops_moved_to = NULL;
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55 GrowableArray<size_t> * MarkSweep::_last_gc_live_oops_size = NULL;
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56 #endif
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57
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58 void MarkSweep::revisit_weak_klass_link(Klass* k) {
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59 _revisit_klass_stack->push(k);
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60 }
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61
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62
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63 void MarkSweep::follow_weak_klass_links() {
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64 // All klasses on the revisit stack are marked at this point.
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65 // Update and follow all subklass, sibling and implementor links.
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66 for (int i = 0; i < _revisit_klass_stack->length(); i++) {
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67 _revisit_klass_stack->at(i)->follow_weak_klass_links(&is_alive,&keep_alive);
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68 }
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69 follow_stack();
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70 }
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71
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72
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73 void MarkSweep::mark_and_follow(oop* p) {
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74 assert(Universe::heap()->is_in_reserved(p),
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75 "we should only be traversing objects here");
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76 oop m = *p;
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77 if (m != NULL && !m->mark()->is_marked()) {
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78 mark_object(m);
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79 m->follow_contents(); // Follow contents of the marked object
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80 }
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81 }
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82
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83 void MarkSweep::_mark_and_push(oop* p) {
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84 // Push marked object, contents will be followed later
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85 oop m = *p;
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86 mark_object(m);
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87 _marking_stack->push(m);
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88 }
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89
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90 MarkSweep::MarkAndPushClosure MarkSweep::mark_and_push_closure;
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91
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92 void MarkSweep::follow_root(oop* p) {
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93 assert(!Universe::heap()->is_in_reserved(p),
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94 "roots shouldn't be things within the heap");
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95 #ifdef VALIDATE_MARK_SWEEP
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96 if (ValidateMarkSweep) {
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97 guarantee(!_root_refs_stack->contains(p), "should only be in here once");
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98 _root_refs_stack->push(p);
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99 }
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100 #endif
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101 oop m = *p;
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102 if (m != NULL && !m->mark()->is_marked()) {
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103 mark_object(m);
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104 m->follow_contents(); // Follow contents of the marked object
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105 }
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106 follow_stack();
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107 }
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108
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109 MarkSweep::FollowRootClosure MarkSweep::follow_root_closure;
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110
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111 void MarkSweep::follow_stack() {
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112 while (!_marking_stack->is_empty()) {
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113 oop obj = _marking_stack->pop();
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114 assert (obj->is_gc_marked(), "p must be marked");
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115 obj->follow_contents();
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116 }
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117 }
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118
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119 MarkSweep::FollowStackClosure MarkSweep::follow_stack_closure;
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120
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121
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122 // We preserve the mark which should be replaced at the end and the location that it
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123 // will go. Note that the object that this markOop belongs to isn't currently at that
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124 // address but it will be after phase4
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125 void MarkSweep::preserve_mark(oop obj, markOop mark) {
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126 // we try to store preserved marks in the to space of the new generation since this
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127 // is storage which should be available. Most of the time this should be sufficient
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128 // space for the marks we need to preserve but if it isn't we fall back in using
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129 // GrowableArrays to keep track of the overflow.
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130 if (_preserved_count < _preserved_count_max) {
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131 _preserved_marks[_preserved_count++].init(obj, mark);
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132 } else {
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133 if (_preserved_mark_stack == NULL) {
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134 _preserved_mark_stack = new (ResourceObj::C_HEAP) GrowableArray<markOop>(40, true);
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135 _preserved_oop_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(40, true);
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136 }
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137 _preserved_mark_stack->push(mark);
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138 _preserved_oop_stack->push(obj);
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139 }
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140 }
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141
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142 MarkSweep::AdjustPointerClosure MarkSweep::adjust_root_pointer_closure(true);
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143 MarkSweep::AdjustPointerClosure MarkSweep::adjust_pointer_closure(false);
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144
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145 void MarkSweep::adjust_marks() {
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146 assert(_preserved_oop_stack == NULL ||
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147 _preserved_oop_stack->length() == _preserved_mark_stack->length(),
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148 "inconsistent preserved oop stacks");
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149
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150 // adjust the oops we saved earlier
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151 for (size_t i = 0; i < _preserved_count; i++) {
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152 _preserved_marks[i].adjust_pointer();
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153 }
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154
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155 // deal with the overflow stack
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156 if (_preserved_oop_stack) {
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157 for (int i = 0; i < _preserved_oop_stack->length(); i++) {
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158 oop* p = _preserved_oop_stack->adr_at(i);
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159 adjust_pointer(p);
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160 }
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161 }
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162 }
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163
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164 void MarkSweep::restore_marks() {
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165 assert(_preserved_oop_stack == NULL ||
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166 _preserved_oop_stack->length() == _preserved_mark_stack->length(),
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167 "inconsistent preserved oop stacks");
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168 if (PrintGC && Verbose) {
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169 gclog_or_tty->print_cr("Restoring %d marks", _preserved_count +
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170 (_preserved_oop_stack ? _preserved_oop_stack->length() : 0));
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171 }
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172
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173 // restore the marks we saved earlier
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174 for (size_t i = 0; i < _preserved_count; i++) {
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175 _preserved_marks[i].restore();
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176 }
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177
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178 // deal with the overflow
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179 if (_preserved_oop_stack) {
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180 for (int i = 0; i < _preserved_oop_stack->length(); i++) {
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181 oop obj = _preserved_oop_stack->at(i);
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182 markOop mark = _preserved_mark_stack->at(i);
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183 obj->set_mark(mark);
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184 }
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185 }
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186 }
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187
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188 #ifdef VALIDATE_MARK_SWEEP
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189
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190 void MarkSweep::track_adjusted_pointer(oop* p, oop newobj, bool isroot) {
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191 if (!ValidateMarkSweep)
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192 return;
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193
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194 if (!isroot) {
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195 if (_pointer_tracking) {
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196 guarantee(_adjusted_pointers->contains(p), "should have seen this pointer");
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197 _adjusted_pointers->remove(p);
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198 }
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199 } else {
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200 ptrdiff_t index = _root_refs_stack->find(p);
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201 if (index != -1) {
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202 int l = _root_refs_stack->length();
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203 if (l > 0 && l - 1 != index) {
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204 oop* last = _root_refs_stack->pop();
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205 assert(last != p, "should be different");
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206 _root_refs_stack->at_put(index, last);
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207 } else {
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208 _root_refs_stack->remove(p);
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209 }
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210 }
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211 }
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212 }
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213
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214
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215 void MarkSweep::check_adjust_pointer(oop* p) {
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216 _adjusted_pointers->push(p);
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217 }
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218
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219
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220 class AdjusterTracker: public OopClosure {
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221 public:
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222 AdjusterTracker() {};
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223 void do_oop(oop* o) { MarkSweep::check_adjust_pointer(o); }
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224 };
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225
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226
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227 void MarkSweep::track_interior_pointers(oop obj) {
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228 if (ValidateMarkSweep) {
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229 _adjusted_pointers->clear();
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230 _pointer_tracking = true;
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231
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232 AdjusterTracker checker;
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233 obj->oop_iterate(&checker);
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234 }
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235 }
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236
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237
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238 void MarkSweep::check_interior_pointers() {
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239 if (ValidateMarkSweep) {
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240 _pointer_tracking = false;
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241 guarantee(_adjusted_pointers->length() == 0, "should have processed the same pointers");
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242 }
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243 }
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244
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245
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246 void MarkSweep::reset_live_oop_tracking(bool at_perm) {
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247 if (ValidateMarkSweep) {
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248 guarantee((size_t)_live_oops->length() == _live_oops_index, "should be at end of live oops");
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249 _live_oops_index = at_perm ? _live_oops_index_at_perm : 0;
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250 }
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251 }
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252
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253
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254 void MarkSweep::register_live_oop(oop p, size_t size) {
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255 if (ValidateMarkSweep) {
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256 _live_oops->push(p);
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257 _live_oops_size->push(size);
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258 _live_oops_index++;
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259 }
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260 }
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261
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262 void MarkSweep::validate_live_oop(oop p, size_t size) {
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263 if (ValidateMarkSweep) {
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264 oop obj = _live_oops->at((int)_live_oops_index);
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265 guarantee(obj == p, "should be the same object");
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266 guarantee(_live_oops_size->at((int)_live_oops_index) == size, "should be the same size");
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267 _live_oops_index++;
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268 }
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269 }
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270
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271 void MarkSweep::live_oop_moved_to(HeapWord* q, size_t size,
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272 HeapWord* compaction_top) {
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273 assert(oop(q)->forwardee() == NULL || oop(q)->forwardee() == oop(compaction_top),
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274 "should be moved to forwarded location");
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275 if (ValidateMarkSweep) {
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276 MarkSweep::validate_live_oop(oop(q), size);
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277 _live_oops_moved_to->push(oop(compaction_top));
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278 }
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279 if (RecordMarkSweepCompaction) {
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280 _cur_gc_live_oops->push(q);
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281 _cur_gc_live_oops_moved_to->push(compaction_top);
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282 _cur_gc_live_oops_size->push(size);
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283 }
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284 }
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285
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286
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287 void MarkSweep::compaction_complete() {
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288 if (RecordMarkSweepCompaction) {
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289 GrowableArray<HeapWord*>* _tmp_live_oops = _cur_gc_live_oops;
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290 GrowableArray<HeapWord*>* _tmp_live_oops_moved_to = _cur_gc_live_oops_moved_to;
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291 GrowableArray<size_t> * _tmp_live_oops_size = _cur_gc_live_oops_size;
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292
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293 _cur_gc_live_oops = _last_gc_live_oops;
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294 _cur_gc_live_oops_moved_to = _last_gc_live_oops_moved_to;
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295 _cur_gc_live_oops_size = _last_gc_live_oops_size;
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296 _last_gc_live_oops = _tmp_live_oops;
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297 _last_gc_live_oops_moved_to = _tmp_live_oops_moved_to;
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298 _last_gc_live_oops_size = _tmp_live_oops_size;
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299 }
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300 }
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301
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302
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303 void MarkSweep::print_new_location_of_heap_address(HeapWord* q) {
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304 if (!RecordMarkSweepCompaction) {
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305 tty->print_cr("Requires RecordMarkSweepCompaction to be enabled");
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306 return;
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307 }
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308
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309 if (_last_gc_live_oops == NULL) {
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310 tty->print_cr("No compaction information gathered yet");
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311 return;
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312 }
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313
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314 for (int i = 0; i < _last_gc_live_oops->length(); i++) {
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315 HeapWord* old_oop = _last_gc_live_oops->at(i);
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316 size_t sz = _last_gc_live_oops_size->at(i);
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317 if (old_oop <= q && q < (old_oop + sz)) {
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318 HeapWord* new_oop = _last_gc_live_oops_moved_to->at(i);
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319 size_t offset = (q - old_oop);
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320 tty->print_cr("Address " PTR_FORMAT, q);
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321 tty->print_cr(" Was in oop " PTR_FORMAT ", size %d, at offset %d", old_oop, sz, offset);
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322 tty->print_cr(" Now in oop " PTR_FORMAT ", actual address " PTR_FORMAT, new_oop, new_oop + offset);
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323 return;
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324 }
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325 }
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326
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327 tty->print_cr("Address " PTR_FORMAT " not found in live oop information from last GC", q);
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328 }
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329 #endif //VALIDATE_MARK_SWEEP
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330
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331 MarkSweep::IsAliveClosure MarkSweep::is_alive;
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332
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333 void MarkSweep::KeepAliveClosure::do_oop(oop* p) {
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334 #ifdef VALIDATE_MARK_SWEEP
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335 if (ValidateMarkSweep) {
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336 if (!Universe::heap()->is_in_reserved(p)) {
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337 _root_refs_stack->push(p);
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338 } else {
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339 _other_refs_stack->push(p);
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340 }
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341 }
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342 #endif
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343 mark_and_push(p);
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344 }
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345
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346 MarkSweep::KeepAliveClosure MarkSweep::keep_alive;
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347
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348 void marksweep_init() { /* empty */ }
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349
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350 #ifndef PRODUCT
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351
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352 void MarkSweep::trace(const char* msg) {
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353 if (TraceMarkSweep)
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354 gclog_or_tty->print("%s", msg);
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355 }
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356
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357 #endif
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