annotate src/share/vm/gc_interface/collectedHeap.cpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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children ba764ed4b6f2
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1 /*
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2 * Copyright 2001-2007 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/_collectedHeap.cpp.incl"
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27
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28
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29 #ifdef ASSERT
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30 int CollectedHeap::_fire_out_of_memory_count = 0;
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31 #endif
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32
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33 // Memory state functions.
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34
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35 CollectedHeap::CollectedHeap() :
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36 _reserved(), _barrier_set(NULL), _is_gc_active(false),
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37 _total_collections(0), _total_full_collections(0),
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38 _max_heap_capacity(0),
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39 _gc_cause(GCCause::_no_gc), _gc_lastcause(GCCause::_no_gc) {
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40 NOT_PRODUCT(_promotion_failure_alot_count = 0;)
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41 NOT_PRODUCT(_promotion_failure_alot_gc_number = 0;)
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42
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43 if (UsePerfData) {
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44 EXCEPTION_MARK;
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45
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46 // create the gc cause jvmstat counters
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47 _perf_gc_cause = PerfDataManager::create_string_variable(SUN_GC, "cause",
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48 80, GCCause::to_string(_gc_cause), CHECK);
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49
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50 _perf_gc_lastcause =
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51 PerfDataManager::create_string_variable(SUN_GC, "lastCause",
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52 80, GCCause::to_string(_gc_lastcause), CHECK);
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53 }
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54 }
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55
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56
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57 #ifndef PRODUCT
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58 void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
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59 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
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60 for (size_t slot = 0; slot < size; slot += 1) {
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61 assert((*(intptr_t*) (addr + slot)) != ((intptr_t) badHeapWordVal),
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62 "Found badHeapWordValue in post-allocation check");
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63 }
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64 }
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65 }
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66
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67 void CollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, size_t size)
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68 {
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69 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
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70 for (size_t slot = 0; slot < size; slot += 1) {
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71 assert((*(intptr_t*) (addr + slot)) == ((intptr_t) badHeapWordVal),
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72 "Found non badHeapWordValue in pre-allocation check");
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73 }
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74 }
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75 }
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76 #endif // PRODUCT
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77
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78 #ifdef ASSERT
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79 void CollectedHeap::check_for_valid_allocation_state() {
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80 Thread *thread = Thread::current();
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81 // How to choose between a pending exception and a potential
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82 // OutOfMemoryError? Don't allow pending exceptions.
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83 // This is a VM policy failure, so how do we exhaustively test it?
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84 assert(!thread->has_pending_exception(),
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85 "shouldn't be allocating with pending exception");
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86 if (StrictSafepointChecks) {
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87 assert(thread->allow_allocation(),
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88 "Allocation done by thread for which allocation is blocked "
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89 "by No_Allocation_Verifier!");
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90 // Allocation of an oop can always invoke a safepoint,
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91 // hence, the true argument
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92 thread->check_for_valid_safepoint_state(true);
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93 }
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94 }
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95 #endif
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96
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97 HeapWord* CollectedHeap::allocate_from_tlab_slow(Thread* thread, size_t size) {
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98
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99 // Retain tlab and allocate object in shared space if
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100 // the amount free in the tlab is too large to discard.
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101 if (thread->tlab().free() > thread->tlab().refill_waste_limit()) {
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102 thread->tlab().record_slow_allocation(size);
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103 return NULL;
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104 }
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105
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106 // Discard tlab and allocate a new one.
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107 // To minimize fragmentation, the last TLAB may be smaller than the rest.
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108 size_t new_tlab_size = thread->tlab().compute_size(size);
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109
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110 thread->tlab().clear_before_allocation();
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111
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112 if (new_tlab_size == 0) {
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113 return NULL;
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114 }
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115
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116 // Allocate a new TLAB...
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117 HeapWord* obj = Universe::heap()->allocate_new_tlab(new_tlab_size);
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118 if (obj == NULL) {
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119 return NULL;
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120 }
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121 if (ZeroTLAB) {
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122 // ..and clear it.
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123 Copy::zero_to_words(obj, new_tlab_size);
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124 } else {
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125 // ...and clear just the allocated object.
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126 Copy::zero_to_words(obj, size);
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127 }
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128 thread->tlab().fill(obj, obj + size, new_tlab_size);
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129 return obj;
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130 }
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131
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132 oop CollectedHeap::new_store_barrier(oop new_obj) {
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133 // %%% This needs refactoring. (It was imported from the server compiler.)
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134 guarantee(can_elide_tlab_store_barriers(), "store barrier elision not supported");
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135 BarrierSet* bs = this->barrier_set();
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136 assert(bs->has_write_region_opt(), "Barrier set does not have write_region");
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137 int new_size = new_obj->size();
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138 bs->write_region(MemRegion((HeapWord*)new_obj, new_size));
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139 return new_obj;
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140 }
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141
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142 bool CollectedHeap::can_elide_permanent_oop_store_barriers() const {
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143 // %%% This needs refactoring. (It was gating logic from the server compiler.)
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144 guarantee(kind() < CollectedHeap::G1CollectedHeap, "");
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145 return !UseConcMarkSweepGC;
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146 }
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147
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148
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149 HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
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150 guarantee(false, "thread-local allocation buffers not supported");
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151 return NULL;
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152 }
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153
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154 void CollectedHeap::fill_all_tlabs(bool retire) {
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155 assert(UseTLAB, "should not reach here");
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156 // See note in ensure_parsability() below.
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157 assert(SafepointSynchronize::is_at_safepoint() ||
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158 !is_init_completed(),
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159 "should only fill tlabs at safepoint");
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160 // The main thread starts allocating via a TLAB even before it
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161 // has added itself to the threads list at vm boot-up.
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162 assert(Threads::first() != NULL,
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163 "Attempt to fill tlabs before main thread has been added"
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164 " to threads list is doomed to failure!");
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165 for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
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166 thread->tlab().make_parsable(retire);
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167 }
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168 }
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169
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170 void CollectedHeap::ensure_parsability(bool retire_tlabs) {
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171 // The second disjunct in the assertion below makes a concession
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172 // for the start-up verification done while the VM is being
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173 // created. Callers be careful that you know that mutators
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174 // aren't going to interfere -- for instance, this is permissible
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175 // if we are still single-threaded and have either not yet
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176 // started allocating (nothing much to verify) or we have
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177 // started allocating but are now a full-fledged JavaThread
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178 // (and have thus made our TLAB's) available for filling.
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179 assert(SafepointSynchronize::is_at_safepoint() ||
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180 !is_init_completed(),
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181 "Should only be called at a safepoint or at start-up"
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182 " otherwise concurrent mutator activity may make heap "
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183 " unparsable again");
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184 if (UseTLAB) {
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185 fill_all_tlabs(retire_tlabs);
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186 }
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187 }
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188
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189 void CollectedHeap::accumulate_statistics_all_tlabs() {
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190 if (UseTLAB) {
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191 assert(SafepointSynchronize::is_at_safepoint() ||
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192 !is_init_completed(),
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193 "should only accumulate statistics on tlabs at safepoint");
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194
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195 ThreadLocalAllocBuffer::accumulate_statistics_before_gc();
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196 }
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197 }
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198
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199 void CollectedHeap::resize_all_tlabs() {
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200 if (UseTLAB) {
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201 assert(SafepointSynchronize::is_at_safepoint() ||
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202 !is_init_completed(),
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203 "should only resize tlabs at safepoint");
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204
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205 ThreadLocalAllocBuffer::resize_all_tlabs();
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206 }
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207 }