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1 /* |
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2 * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. |
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8 * |
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9 * This code is distributed in the hope that it will be useful, but WITHOUT |
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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12 * version 2 for more details (a copy is included in the LICENSE file that |
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13 * accompanied this code). |
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14 * |
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15 * You should have received a copy of the GNU General Public License version |
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16 * 2 along with this work; if not, write to the Free Software Foundation, |
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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18 * |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
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22 * |
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23 */ |
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24 |
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25 #include "precompiled.hpp" |
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26 #include "gc_implementation/shared/collectorCounters.hpp" |
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27 #include "gc_implementation/shared/parGCAllocBuffer.hpp" |
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28 #include "memory/allocation.inline.hpp" |
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29 #include "memory/blockOffsetTable.inline.hpp" |
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30 #include "memory/generation.inline.hpp" |
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31 #include "memory/generationSpec.hpp" |
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32 #include "memory/space.hpp" |
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33 #include "memory/tenuredGeneration.hpp" |
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34 #include "oops/oop.inline.hpp" |
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35 #include "runtime/java.hpp" |
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36 #include "utilities/macros.hpp" |
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37 |
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38 TenuredGeneration::TenuredGeneration(ReservedSpace rs, |
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39 size_t initial_byte_size, int level, |
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40 GenRemSet* remset) : |
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41 OneContigSpaceCardGeneration(rs, initial_byte_size, |
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42 level, remset, NULL) |
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43 { |
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44 HeapWord* bottom = (HeapWord*) _virtual_space.low(); |
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45 HeapWord* end = (HeapWord*) _virtual_space.high(); |
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46 _the_space = new TenuredSpace(_bts, MemRegion(bottom, end)); |
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47 _the_space->reset_saved_mark(); |
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48 _shrink_factor = 0; |
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49 _capacity_at_prologue = 0; |
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50 |
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51 _gc_stats = new GCStats(); |
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52 |
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53 // initialize performance counters |
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54 |
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55 const char* gen_name = "old"; |
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56 |
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57 // Generation Counters -- generation 1, 1 subspace |
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58 _gen_counters = new GenerationCounters(gen_name, 1, 1, &_virtual_space); |
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59 |
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60 _gc_counters = new CollectorCounters("MSC", 1); |
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61 |
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62 _space_counters = new CSpaceCounters(gen_name, 0, |
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63 _virtual_space.reserved_size(), |
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64 _the_space, _gen_counters); |
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65 #if INCLUDE_ALL_GCS |
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66 if (UseParNewGC) { |
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67 typedef ParGCAllocBufferWithBOT* ParGCAllocBufferWithBOTPtr; |
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68 _alloc_buffers = NEW_C_HEAP_ARRAY(ParGCAllocBufferWithBOTPtr, |
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69 ParallelGCThreads, mtGC); |
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70 if (_alloc_buffers == NULL) |
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71 vm_exit_during_initialization("Could not allocate alloc_buffers"); |
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72 for (uint i = 0; i < ParallelGCThreads; i++) { |
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73 _alloc_buffers[i] = |
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74 new ParGCAllocBufferWithBOT(OldPLABSize, _bts); |
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75 if (_alloc_buffers[i] == NULL) |
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76 vm_exit_during_initialization("Could not allocate alloc_buffers"); |
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77 } |
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78 } else { |
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79 _alloc_buffers = NULL; |
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80 } |
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81 #endif // INCLUDE_ALL_GCS |
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82 } |
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83 |
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84 |
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85 const char* TenuredGeneration::name() const { |
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86 return "tenured generation"; |
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87 } |
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88 |
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89 void TenuredGeneration::gc_prologue(bool full) { |
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90 _capacity_at_prologue = capacity(); |
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91 _used_at_prologue = used(); |
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92 if (VerifyBeforeGC) { |
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93 verify_alloc_buffers_clean(); |
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94 } |
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95 } |
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96 |
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97 void TenuredGeneration::gc_epilogue(bool full) { |
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98 if (VerifyAfterGC) { |
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99 verify_alloc_buffers_clean(); |
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100 } |
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101 OneContigSpaceCardGeneration::gc_epilogue(full); |
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102 } |
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103 |
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104 |
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105 bool TenuredGeneration::should_collect(bool full, |
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106 size_t size, |
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107 bool is_tlab) { |
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108 // This should be one big conditional or (||), but I want to be able to tell |
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109 // why it returns what it returns (without re-evaluating the conditionals |
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110 // in case they aren't idempotent), so I'm doing it this way. |
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111 // DeMorgan says it's okay. |
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112 bool result = false; |
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113 if (!result && full) { |
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114 result = true; |
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115 if (PrintGC && Verbose) { |
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116 gclog_or_tty->print_cr("TenuredGeneration::should_collect: because" |
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117 " full"); |
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118 } |
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119 } |
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120 if (!result && should_allocate(size, is_tlab)) { |
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121 result = true; |
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122 if (PrintGC && Verbose) { |
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123 gclog_or_tty->print_cr("TenuredGeneration::should_collect: because" |
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124 " should_allocate(" SIZE_FORMAT ")", |
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125 size); |
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126 } |
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127 } |
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128 // If we don't have very much free space. |
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129 // XXX: 10000 should be a percentage of the capacity!!! |
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130 if (!result && free() < 10000) { |
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131 result = true; |
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132 if (PrintGC && Verbose) { |
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133 gclog_or_tty->print_cr("TenuredGeneration::should_collect: because" |
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134 " free(): " SIZE_FORMAT, |
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135 free()); |
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136 } |
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137 } |
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138 // If we had to expand to accomodate promotions from younger generations |
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139 if (!result && _capacity_at_prologue < capacity()) { |
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140 result = true; |
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141 if (PrintGC && Verbose) { |
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142 gclog_or_tty->print_cr("TenuredGeneration::should_collect: because" |
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143 "_capacity_at_prologue: " SIZE_FORMAT " < capacity(): " SIZE_FORMAT, |
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144 _capacity_at_prologue, capacity()); |
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145 } |
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146 } |
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147 return result; |
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148 } |
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149 |
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150 void TenuredGeneration::collect(bool full, |
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151 bool clear_all_soft_refs, |
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152 size_t size, |
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153 bool is_tlab) { |
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154 retire_alloc_buffers_before_full_gc(); |
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155 OneContigSpaceCardGeneration::collect(full, clear_all_soft_refs, |
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156 size, is_tlab); |
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157 } |
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158 |
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159 void TenuredGeneration::compute_new_size() { |
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160 assert_locked_or_safepoint(Heap_lock); |
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161 |
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162 // Compute some numbers about the state of the heap. |
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163 const size_t used_after_gc = used(); |
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164 const size_t capacity_after_gc = capacity(); |
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165 |
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166 CardGeneration::compute_new_size(); |
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167 |
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168 assert(used() == used_after_gc && used_after_gc <= capacity(), |
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169 err_msg("used: " SIZE_FORMAT " used_after_gc: " SIZE_FORMAT |
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170 " capacity: " SIZE_FORMAT, used(), used_after_gc, capacity())); |
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171 } |
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172 void TenuredGeneration::update_gc_stats(int current_level, |
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173 bool full) { |
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174 // If the next lower level(s) has been collected, gather any statistics |
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175 // that are of interest at this point. |
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176 if (!full && (current_level + 1) == level()) { |
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177 // Calculate size of data promoted from the younger generations |
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178 // before doing the collection. |
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179 size_t used_before_gc = used(); |
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180 |
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181 // If the younger gen collections were skipped, then the |
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182 // number of promoted bytes will be 0 and adding it to the |
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183 // average will incorrectly lessen the average. It is, however, |
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184 // also possible that no promotion was needed. |
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185 if (used_before_gc >= _used_at_prologue) { |
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186 size_t promoted_in_bytes = used_before_gc - _used_at_prologue; |
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187 gc_stats()->avg_promoted()->sample(promoted_in_bytes); |
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188 } |
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189 } |
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190 } |
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191 |
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192 void TenuredGeneration::update_counters() { |
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193 if (UsePerfData) { |
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194 _space_counters->update_all(); |
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195 _gen_counters->update_all(); |
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196 } |
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197 } |
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198 |
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199 |
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200 #if INCLUDE_ALL_GCS |
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201 oop TenuredGeneration::par_promote(int thread_num, |
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202 oop old, markOop m, size_t word_sz) { |
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203 |
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204 ParGCAllocBufferWithBOT* buf = _alloc_buffers[thread_num]; |
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205 HeapWord* obj_ptr = buf->allocate(word_sz); |
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206 bool is_lab = true; |
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207 if (obj_ptr == NULL) { |
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208 #ifndef PRODUCT |
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209 if (Universe::heap()->promotion_should_fail()) { |
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210 return NULL; |
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211 } |
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212 #endif // #ifndef PRODUCT |
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213 |
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214 // Slow path: |
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215 if (word_sz * 100 < ParallelGCBufferWastePct * buf->word_sz()) { |
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216 // Is small enough; abandon this buffer and start a new one. |
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217 size_t buf_size = buf->word_sz(); |
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218 HeapWord* buf_space = |
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219 TenuredGeneration::par_allocate(buf_size, false); |
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220 if (buf_space == NULL) { |
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221 buf_space = expand_and_allocate(buf_size, false, true /* parallel*/); |
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222 } |
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223 if (buf_space != NULL) { |
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224 buf->retire(false, false); |
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225 buf->set_buf(buf_space); |
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226 obj_ptr = buf->allocate(word_sz); |
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227 assert(obj_ptr != NULL, "Buffer was definitely big enough..."); |
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228 } |
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229 }; |
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230 // Otherwise, buffer allocation failed; try allocating object |
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231 // individually. |
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232 if (obj_ptr == NULL) { |
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233 obj_ptr = TenuredGeneration::par_allocate(word_sz, false); |
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234 if (obj_ptr == NULL) { |
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235 obj_ptr = expand_and_allocate(word_sz, false, true /* parallel */); |
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236 } |
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237 } |
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238 if (obj_ptr == NULL) return NULL; |
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239 } |
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240 assert(obj_ptr != NULL, "program logic"); |
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241 Copy::aligned_disjoint_words((HeapWord*)old, obj_ptr, word_sz); |
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242 oop obj = oop(obj_ptr); |
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243 // Restore the mark word copied above. |
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244 obj->set_mark(m); |
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245 return obj; |
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246 } |
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247 |
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248 void TenuredGeneration::par_promote_alloc_undo(int thread_num, |
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249 HeapWord* obj, |
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250 size_t word_sz) { |
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251 ParGCAllocBufferWithBOT* buf = _alloc_buffers[thread_num]; |
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252 if (buf->contains(obj)) { |
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253 guarantee(buf->contains(obj + word_sz - 1), |
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254 "should contain whole object"); |
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255 buf->undo_allocation(obj, word_sz); |
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256 } else { |
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257 CollectedHeap::fill_with_object(obj, word_sz); |
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258 } |
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259 } |
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260 |
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261 void TenuredGeneration::par_promote_alloc_done(int thread_num) { |
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262 ParGCAllocBufferWithBOT* buf = _alloc_buffers[thread_num]; |
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263 buf->retire(true, ParallelGCRetainPLAB); |
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264 } |
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265 |
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266 void TenuredGeneration::retire_alloc_buffers_before_full_gc() { |
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267 if (UseParNewGC) { |
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268 for (uint i = 0; i < ParallelGCThreads; i++) { |
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269 _alloc_buffers[i]->retire(true /*end_of_gc*/, false /*retain*/); |
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270 } |
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271 } |
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272 } |
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273 |
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274 // Verify that any retained parallel allocation buffers do not |
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275 // intersect with dirty cards. |
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276 void TenuredGeneration::verify_alloc_buffers_clean() { |
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277 if (UseParNewGC) { |
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278 for (uint i = 0; i < ParallelGCThreads; i++) { |
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279 _rs->verify_aligned_region_empty(_alloc_buffers[i]->range()); |
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280 } |
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281 } |
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282 } |
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283 |
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284 #else // INCLUDE_ALL_GCS |
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285 void TenuredGeneration::retire_alloc_buffers_before_full_gc() {} |
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286 void TenuredGeneration::verify_alloc_buffers_clean() {} |
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287 #endif // INCLUDE_ALL_GCS |
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288 |
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289 bool TenuredGeneration::promotion_attempt_is_safe(size_t max_promotion_in_bytes) const { |
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290 size_t available = max_contiguous_available(); |
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291 size_t av_promo = (size_t)gc_stats()->avg_promoted()->padded_average(); |
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292 bool res = (available >= av_promo) || (available >= max_promotion_in_bytes); |
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293 if (PrintGC && Verbose) { |
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294 gclog_or_tty->print_cr( |
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295 "Tenured: promo attempt is%s safe: available("SIZE_FORMAT") %s av_promo("SIZE_FORMAT")," |
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296 "max_promo("SIZE_FORMAT")", |
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297 res? "":" not", available, res? ">=":"<", |
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298 av_promo, max_promotion_in_bytes); |
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299 } |
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300 return res; |
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301 } |