1 /* |
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2 * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. |
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8 * |
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9 * This code is distributed in the hope that it will be useful, but WITHOUT |
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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12 * version 2 for more details (a copy is included in the LICENSE file that |
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13 * accompanied this code). |
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14 * |
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15 * You should have received a copy of the GNU General Public License version |
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16 * 2 along with this work; if not, write to the Free Software Foundation, |
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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18 * |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
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22 * |
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23 */ |
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24 |
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25 #ifndef SHARE_VM_GC_G1_SATBMARKQUEUE_HPP |
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26 #define SHARE_VM_GC_G1_SATBMARKQUEUE_HPP |
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27 |
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28 #include "gc/g1/ptrQueue.hpp" |
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29 #include "memory/allocation.hpp" |
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30 |
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31 class JavaThread; |
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32 class SATBMarkQueueSet; |
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33 |
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34 // Base class for processing the contents of a SATB buffer. |
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35 class SATBBufferClosure : public StackObj { |
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36 protected: |
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37 ~SATBBufferClosure() { } |
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38 |
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39 public: |
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40 // Process the SATB entries in the designated buffer range. |
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41 virtual void do_buffer(void** buffer, size_t size) = 0; |
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42 }; |
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43 |
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44 // A PtrQueue whose elements are (possibly stale) pointers to object heads. |
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45 class SATBMarkQueue: public PtrQueue { |
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46 friend class SATBMarkQueueSet; |
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47 |
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48 private: |
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49 // Filter out unwanted entries from the buffer. |
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50 inline void filter(); |
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51 |
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52 // Removes entries from the buffer that are no longer needed. |
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53 template<typename Filter> |
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54 inline void apply_filter(Filter filter_out); |
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55 |
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56 public: |
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57 SATBMarkQueue(SATBMarkQueueSet* qset, bool permanent = false); |
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58 |
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59 // Process queue entries and free resources. |
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60 void flush(); |
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61 |
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62 // Apply cl to the active part of the buffer. |
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63 // Prerequisite: Must be at a safepoint. |
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64 void apply_closure_and_empty(SATBBufferClosure* cl); |
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65 |
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66 // Overrides PtrQueue::should_enqueue_buffer(). See the method's |
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67 // definition for more information. |
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68 virtual bool should_enqueue_buffer(); |
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69 |
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70 #ifndef PRODUCT |
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71 // Helpful for debugging |
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72 void print(const char* name); |
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73 #endif // PRODUCT |
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74 |
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75 // Compiler support. |
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76 static ByteSize byte_offset_of_index() { |
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77 return PtrQueue::byte_offset_of_index<SATBMarkQueue>(); |
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78 } |
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79 using PtrQueue::byte_width_of_index; |
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80 |
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81 static ByteSize byte_offset_of_buf() { |
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82 return PtrQueue::byte_offset_of_buf<SATBMarkQueue>(); |
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83 } |
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84 using PtrQueue::byte_width_of_buf; |
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85 |
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86 static ByteSize byte_offset_of_active() { |
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87 return PtrQueue::byte_offset_of_active<SATBMarkQueue>(); |
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88 } |
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89 using PtrQueue::byte_width_of_active; |
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90 |
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91 }; |
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92 |
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93 class SATBMarkQueueSet: public PtrQueueSet { |
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94 SATBMarkQueue _shared_satb_queue; |
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95 size_t _buffer_enqueue_threshold; |
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96 |
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97 #ifdef ASSERT |
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98 void dump_active_states(bool expected_active); |
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99 void verify_active_states(bool expected_active); |
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100 #endif // ASSERT |
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101 |
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102 protected: |
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103 SATBMarkQueueSet(); |
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104 ~SATBMarkQueueSet() {} |
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105 |
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106 template<typename Filter> |
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107 void apply_filter(Filter filter, SATBMarkQueue* queue) { |
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108 queue->apply_filter(filter); |
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109 } |
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110 |
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111 void initialize(Monitor* cbl_mon, Mutex* fl_lock, |
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112 int process_completed_threshold, |
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113 uint buffer_enqueue_threshold_percentage, |
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114 Mutex* lock); |
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115 |
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116 public: |
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117 virtual SATBMarkQueue& satb_queue_for_thread(JavaThread* const t) const = 0; |
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118 |
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119 // Apply "set_active(active)" to all SATB queues in the set. It should be |
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120 // called only with the world stopped. The method will assert that the |
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121 // SATB queues of all threads it visits, as well as the SATB queue |
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122 // set itself, has an active value same as expected_active. |
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123 void set_active_all_threads(bool active, bool expected_active); |
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124 |
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125 size_t buffer_enqueue_threshold() const { return _buffer_enqueue_threshold; } |
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126 virtual void filter(SATBMarkQueue* queue) = 0; |
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127 |
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128 // Filter all the currently-active SATB buffers. |
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129 void filter_thread_buffers(); |
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130 |
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131 // If there exists some completed buffer, pop and process it, and |
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132 // return true. Otherwise return false. Processing a buffer |
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133 // consists of applying the closure to the active range of the |
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134 // buffer; the leading entries may be excluded due to filtering. |
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135 bool apply_closure_to_completed_buffer(SATBBufferClosure* cl); |
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136 |
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137 #ifndef PRODUCT |
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138 // Helpful for debugging |
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139 void print_all(const char* msg); |
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140 #endif // PRODUCT |
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141 |
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142 SATBMarkQueue* shared_satb_queue() { return &_shared_satb_queue; } |
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143 |
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144 // If a marking is being abandoned, reset any unprocessed log buffers. |
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145 void abandon_partial_marking(); |
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146 }; |
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147 |
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148 inline void SATBMarkQueue::filter() { |
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149 static_cast<SATBMarkQueueSet*>(qset())->filter(this); |
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150 } |
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151 |
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152 // Removes entries from the buffer that are no longer needed, as |
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153 // determined by filter. If e is a void* entry in the buffer, |
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154 // filter_out(e) must be a valid expression whose value is convertible |
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155 // to bool. Entries are removed (filtered out) if the result is true, |
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156 // retained if false. |
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157 template<typename Filter> |
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158 inline void SATBMarkQueue::apply_filter(Filter filter_out) { |
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159 void** buf = this->_buf; |
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160 |
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161 if (buf == NULL) { |
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162 // nothing to do |
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163 return; |
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164 } |
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165 |
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166 // Two-fingered compaction toward the end. |
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167 void** src = &buf[this->index()]; |
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168 void** dst = &buf[this->capacity()]; |
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169 assert(src <= dst, "invariant"); |
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170 for ( ; src < dst; ++src) { |
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171 // Search low to high for an entry to keep. |
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172 void* entry = *src; |
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173 if (!filter_out(entry)) { |
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174 // Found keeper. Search high to low for an entry to discard. |
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175 while (src < --dst) { |
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176 if (filter_out(*dst)) { |
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177 *dst = entry; // Replace discard with keeper. |
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178 break; |
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179 } |
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180 } |
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181 // If discard search failed (src == dst), the outer loop will also end. |
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182 } |
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183 } |
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184 // dst points to the lowest retained entry, or the end of the buffer |
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185 // if all the entries were filtered out. |
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186 this->set_index(dst - buf); |
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187 } |
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188 |
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189 #endif // SHARE_VM_GC_G1_SATBMARKQUEUE_HPP |
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