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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/_ptrQueue.cpp.incl" |
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27 |
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28 PtrQueue::PtrQueue(PtrQueueSet* qset_, bool perm) : |
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29 _qset(qset_), _buf(NULL), _index(0), _active(false), |
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30 _perm(perm), _lock(NULL) |
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31 {} |
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32 |
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33 PtrQueue::~PtrQueue() { |
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34 if (!_perm && _buf != NULL) { |
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35 if (_index == _sz) { |
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36 // No work to do. |
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37 qset()->deallocate_buffer(_buf); |
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38 } else { |
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39 // We must NULL out the unused entries, then enqueue. |
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40 for (size_t i = 0; i < _index; i += oopSize) { |
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41 _buf[byte_index_to_index((int)i)] = NULL; |
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42 } |
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43 qset()->enqueue_complete_buffer(_buf); |
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44 _buf = NULL; |
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45 } |
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46 } |
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47 } |
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48 |
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49 |
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50 static int byte_index_to_index(int ind) { |
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51 assert((ind % oopSize) == 0, "Invariant."); |
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52 return ind / oopSize; |
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53 } |
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54 |
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55 static int index_to_byte_index(int byte_ind) { |
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56 return byte_ind * oopSize; |
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57 } |
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58 |
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59 void PtrQueue::enqueue_known_active(void* ptr) { |
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60 assert(0 <= _index && _index <= _sz, "Invariant."); |
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61 assert(_index == 0 || _buf != NULL, "invariant"); |
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62 |
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63 while (_index == 0) { |
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64 handle_zero_index(); |
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65 } |
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66 assert(_index > 0, "postcondition"); |
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67 |
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68 _index -= oopSize; |
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69 _buf[byte_index_to_index((int)_index)] = ptr; |
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70 assert(0 <= _index && _index <= _sz, "Invariant."); |
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71 } |
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72 |
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73 void PtrQueue::locking_enqueue_completed_buffer(void** buf) { |
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74 assert(_lock->owned_by_self(), "Required."); |
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75 _lock->unlock(); |
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76 qset()->enqueue_complete_buffer(buf); |
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77 // We must relock only because the caller will unlock, for the normal |
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78 // case. |
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79 _lock->lock_without_safepoint_check(); |
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80 } |
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81 |
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82 |
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83 PtrQueueSet::PtrQueueSet(bool notify_when_complete) : |
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84 _max_completed_queue(0), |
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85 _cbl_mon(NULL), _fl_lock(NULL), |
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86 _notify_when_complete(notify_when_complete), |
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87 _sz(0), |
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88 _completed_buffers_head(NULL), |
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89 _completed_buffers_tail(NULL), |
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90 _n_completed_buffers(0), |
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91 _process_completed_threshold(0), _process_completed(false), |
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92 _buf_free_list(NULL), _buf_free_list_sz(0) |
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93 {} |
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94 |
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95 void** PtrQueueSet::allocate_buffer() { |
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96 assert(_sz > 0, "Didn't set a buffer size."); |
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97 MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag); |
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98 if (_buf_free_list != NULL) { |
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99 void** res = _buf_free_list; |
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100 _buf_free_list = (void**)_buf_free_list[0]; |
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101 _buf_free_list_sz--; |
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102 // Just override the next pointer with NULL, just in case we scan this part |
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103 // of the buffer. |
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104 res[0] = NULL; |
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105 return res; |
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106 } else { |
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107 return NEW_C_HEAP_ARRAY(void*, _sz); |
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108 } |
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109 } |
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110 |
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111 void PtrQueueSet::deallocate_buffer(void** buf) { |
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112 assert(_sz > 0, "Didn't set a buffer size."); |
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113 MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag); |
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114 buf[0] = (void*)_buf_free_list; |
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115 _buf_free_list = buf; |
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116 _buf_free_list_sz++; |
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117 } |
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118 |
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119 void PtrQueueSet::reduce_free_list() { |
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120 // For now we'll adopt the strategy of deleting half. |
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121 MutexLockerEx x(_fl_lock, Mutex::_no_safepoint_check_flag); |
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122 size_t n = _buf_free_list_sz / 2; |
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123 while (n > 0) { |
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124 assert(_buf_free_list != NULL, "_buf_free_list_sz must be wrong."); |
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125 void** head = _buf_free_list; |
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126 _buf_free_list = (void**)_buf_free_list[0]; |
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127 FREE_C_HEAP_ARRAY(void*,head); |
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128 n--; |
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129 } |
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130 } |
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131 |
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132 void PtrQueueSet::enqueue_complete_buffer(void** buf, size_t index, bool ignore_max_completed) { |
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133 // I use explicit locking here because there's a bailout in the middle. |
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134 _cbl_mon->lock_without_safepoint_check(); |
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135 |
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136 Thread* thread = Thread::current(); |
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137 assert( ignore_max_completed || |
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138 thread->is_Java_thread() || |
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139 SafepointSynchronize::is_at_safepoint(), |
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140 "invariant" ); |
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141 ignore_max_completed = ignore_max_completed || !thread->is_Java_thread(); |
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142 |
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143 if (!ignore_max_completed && _max_completed_queue > 0 && |
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144 _n_completed_buffers >= (size_t) _max_completed_queue) { |
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145 _cbl_mon->unlock(); |
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146 bool b = mut_process_buffer(buf); |
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147 if (b) { |
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148 deallocate_buffer(buf); |
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149 return; |
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150 } |
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151 |
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152 // Otherwise, go ahead and enqueue the buffer. Must reaquire the lock. |
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153 _cbl_mon->lock_without_safepoint_check(); |
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154 } |
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155 |
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156 // Here we still hold the _cbl_mon. |
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157 CompletedBufferNode* cbn = new CompletedBufferNode; |
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158 cbn->buf = buf; |
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159 cbn->next = NULL; |
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160 cbn->index = index; |
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161 if (_completed_buffers_tail == NULL) { |
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162 assert(_completed_buffers_head == NULL, "Well-formedness"); |
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163 _completed_buffers_head = cbn; |
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164 _completed_buffers_tail = cbn; |
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165 } else { |
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166 _completed_buffers_tail->next = cbn; |
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167 _completed_buffers_tail = cbn; |
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168 } |
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169 _n_completed_buffers++; |
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170 |
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171 if (!_process_completed && |
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172 _n_completed_buffers == _process_completed_threshold) { |
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173 _process_completed = true; |
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174 if (_notify_when_complete) |
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175 _cbl_mon->notify_all(); |
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176 } |
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177 debug_only(assert_completed_buffer_list_len_correct_locked()); |
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178 _cbl_mon->unlock(); |
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179 } |
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180 |
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181 int PtrQueueSet::completed_buffers_list_length() { |
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182 int n = 0; |
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183 CompletedBufferNode* cbn = _completed_buffers_head; |
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184 while (cbn != NULL) { |
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185 n++; |
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186 cbn = cbn->next; |
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187 } |
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188 return n; |
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189 } |
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190 |
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191 void PtrQueueSet::assert_completed_buffer_list_len_correct() { |
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192 MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag); |
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193 assert_completed_buffer_list_len_correct_locked(); |
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194 } |
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195 |
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196 void PtrQueueSet::assert_completed_buffer_list_len_correct_locked() { |
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197 guarantee((size_t)completed_buffers_list_length() == _n_completed_buffers, |
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198 "Completed buffer length is wrong."); |
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199 } |
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200 |
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201 void PtrQueueSet::set_buffer_size(size_t sz) { |
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202 assert(_sz == 0 && sz > 0, "Should be called only once."); |
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203 _sz = sz * oopSize; |
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204 } |
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205 |
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206 void PtrQueueSet::set_process_completed_threshold(size_t sz) { |
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207 _process_completed_threshold = sz; |
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208 } |