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1 /* |
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2 * Copyright (c) 2001, 2014, 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 "memory/allocation.hpp" |
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27 #include "memory/allocation.inline.hpp" |
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28 #include "runtime/os.hpp" |
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29 #include "utilities/workgroup.hpp" |
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30 |
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31 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC |
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32 |
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33 // Definitions of WorkGang methods. |
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34 |
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35 AbstractWorkGang::AbstractWorkGang(const char* name, |
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36 bool are_GC_task_threads, |
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37 bool are_ConcurrentGC_threads) : |
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38 _name(name), |
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39 _are_GC_task_threads(are_GC_task_threads), |
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40 _are_ConcurrentGC_threads(are_ConcurrentGC_threads) { |
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41 |
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42 assert(!(are_GC_task_threads && are_ConcurrentGC_threads), |
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43 "They cannot both be STW GC and Concurrent threads" ); |
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44 |
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45 // Other initialization. |
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46 _monitor = new Monitor(/* priority */ Mutex::leaf, |
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47 /* name */ "WorkGroup monitor", |
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48 /* allow_vm_block */ are_GC_task_threads); |
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49 assert(monitor() != NULL, "Failed to allocate monitor"); |
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50 _terminate = false; |
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51 _task = NULL; |
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52 _sequence_number = 0; |
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53 _started_workers = 0; |
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54 _finished_workers = 0; |
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55 } |
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56 |
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57 WorkGang::WorkGang(const char* name, |
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58 uint workers, |
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59 bool are_GC_task_threads, |
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60 bool are_ConcurrentGC_threads) : |
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61 AbstractWorkGang(name, are_GC_task_threads, are_ConcurrentGC_threads) { |
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62 _total_workers = workers; |
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63 } |
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64 |
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65 GangWorker* WorkGang::allocate_worker(uint which) { |
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66 GangWorker* new_worker = new GangWorker(this, which); |
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67 return new_worker; |
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68 } |
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69 |
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70 // The current implementation will exit if the allocation |
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71 // of any worker fails. Still, return a boolean so that |
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72 // a future implementation can possibly do a partial |
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73 // initialization of the workers and report such to the |
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74 // caller. |
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75 bool WorkGang::initialize_workers() { |
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76 |
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77 if (TraceWorkGang) { |
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78 tty->print_cr("Constructing work gang %s with %d threads", |
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79 name(), |
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80 total_workers()); |
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81 } |
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82 _gang_workers = NEW_C_HEAP_ARRAY(GangWorker*, total_workers(), mtInternal); |
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83 if (gang_workers() == NULL) { |
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84 vm_exit_out_of_memory(0, OOM_MALLOC_ERROR, "Cannot create GangWorker array."); |
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85 return false; |
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86 } |
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87 os::ThreadType worker_type; |
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88 if (are_ConcurrentGC_threads()) { |
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89 worker_type = os::cgc_thread; |
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90 } else { |
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91 worker_type = os::pgc_thread; |
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92 } |
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93 for (uint worker = 0; worker < total_workers(); worker += 1) { |
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94 GangWorker* new_worker = allocate_worker(worker); |
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95 assert(new_worker != NULL, "Failed to allocate GangWorker"); |
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96 _gang_workers[worker] = new_worker; |
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97 if (new_worker == NULL || !os::create_thread(new_worker, worker_type)) { |
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98 vm_exit_out_of_memory(0, OOM_MALLOC_ERROR, |
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99 "Cannot create worker GC thread. Out of system resources."); |
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100 return false; |
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101 } |
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102 if (!DisableStartThread) { |
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103 os::start_thread(new_worker); |
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104 } |
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105 } |
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106 return true; |
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107 } |
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108 |
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109 AbstractWorkGang::~AbstractWorkGang() { |
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110 if (TraceWorkGang) { |
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111 tty->print_cr("Destructing work gang %s", name()); |
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112 } |
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113 stop(); // stop all the workers |
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114 for (uint worker = 0; worker < total_workers(); worker += 1) { |
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115 delete gang_worker(worker); |
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116 } |
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117 delete gang_workers(); |
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118 delete monitor(); |
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119 } |
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120 |
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121 GangWorker* AbstractWorkGang::gang_worker(uint i) const { |
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122 // Array index bounds checking. |
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123 GangWorker* result = NULL; |
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124 assert(gang_workers() != NULL, "No workers for indexing"); |
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125 assert(((i >= 0) && (i < total_workers())), "Worker index out of bounds"); |
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126 result = _gang_workers[i]; |
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127 assert(result != NULL, "Indexing to null worker"); |
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128 return result; |
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129 } |
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130 |
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131 void WorkGang::run_task(AbstractGangTask* task) { |
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132 run_task(task, total_workers()); |
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133 } |
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134 |
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135 void WorkGang::run_task(AbstractGangTask* task, uint no_of_parallel_workers) { |
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136 task->set_for_termination(no_of_parallel_workers); |
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137 |
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138 // This thread is executed by the VM thread which does not block |
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139 // on ordinary MutexLocker's. |
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140 MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag); |
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141 if (TraceWorkGang) { |
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142 tty->print_cr("Running work gang %s task %s", name(), task->name()); |
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143 } |
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144 // Tell all the workers to run a task. |
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145 assert(task != NULL, "Running a null task"); |
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146 // Initialize. |
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147 _task = task; |
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148 _sequence_number += 1; |
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149 _started_workers = 0; |
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150 _finished_workers = 0; |
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151 // Tell the workers to get to work. |
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152 monitor()->notify_all(); |
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153 // Wait for them to be finished |
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154 while (finished_workers() < no_of_parallel_workers) { |
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155 if (TraceWorkGang) { |
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156 tty->print_cr("Waiting in work gang %s: %d/%d finished sequence %d", |
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157 name(), finished_workers(), no_of_parallel_workers, |
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158 _sequence_number); |
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159 } |
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160 monitor()->wait(/* no_safepoint_check */ true); |
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161 } |
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162 _task = NULL; |
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163 if (TraceWorkGang) { |
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164 tty->print_cr("\nFinished work gang %s: %d/%d sequence %d", |
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165 name(), finished_workers(), no_of_parallel_workers, |
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166 _sequence_number); |
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167 Thread* me = Thread::current(); |
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168 tty->print_cr(" T: 0x%x VM_thread: %d", me, me->is_VM_thread()); |
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169 } |
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170 } |
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171 |
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172 void FlexibleWorkGang::run_task(AbstractGangTask* task) { |
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173 // If active_workers() is passed, _finished_workers |
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174 // must only be incremented for workers that find non_null |
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175 // work (as opposed to all those that just check that the |
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176 // task is not null). |
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177 WorkGang::run_task(task, (uint) active_workers()); |
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178 } |
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179 |
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180 void AbstractWorkGang::stop() { |
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181 // Tell all workers to terminate, then wait for them to become inactive. |
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182 MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag); |
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183 if (TraceWorkGang) { |
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184 tty->print_cr("Stopping work gang %s task %s", name(), task()->name()); |
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185 } |
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186 _task = NULL; |
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187 _terminate = true; |
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188 monitor()->notify_all(); |
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189 while (finished_workers() < active_workers()) { |
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190 if (TraceWorkGang) { |
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191 tty->print_cr("Waiting in work gang %s: %d/%d finished", |
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192 name(), finished_workers(), active_workers()); |
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193 } |
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194 monitor()->wait(/* no_safepoint_check */ true); |
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195 } |
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196 } |
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197 |
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198 void AbstractWorkGang::internal_worker_poll(WorkData* data) const { |
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199 assert(monitor()->owned_by_self(), "worker_poll is an internal method"); |
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200 assert(data != NULL, "worker data is null"); |
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201 data->set_terminate(terminate()); |
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202 data->set_task(task()); |
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203 data->set_sequence_number(sequence_number()); |
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204 } |
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205 |
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206 void AbstractWorkGang::internal_note_start() { |
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207 assert(monitor()->owned_by_self(), "note_finish is an internal method"); |
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208 _started_workers += 1; |
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209 } |
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210 |
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211 void AbstractWorkGang::internal_note_finish() { |
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212 assert(monitor()->owned_by_self(), "note_finish is an internal method"); |
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213 _finished_workers += 1; |
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214 } |
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215 |
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216 void AbstractWorkGang::print_worker_threads_on(outputStream* st) const { |
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217 uint num_thr = total_workers(); |
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218 for (uint i = 0; i < num_thr; i++) { |
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219 gang_worker(i)->print_on(st); |
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220 st->cr(); |
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221 } |
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222 } |
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223 |
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224 void AbstractWorkGang::threads_do(ThreadClosure* tc) const { |
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225 assert(tc != NULL, "Null ThreadClosure"); |
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226 uint num_thr = total_workers(); |
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227 for (uint i = 0; i < num_thr; i++) { |
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228 tc->do_thread(gang_worker(i)); |
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229 } |
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230 } |
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231 |
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232 // GangWorker methods. |
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233 |
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234 GangWorker::GangWorker(AbstractWorkGang* gang, uint id) { |
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235 _gang = gang; |
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236 set_id(id); |
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237 set_name("Gang worker#%d (%s)", id, gang->name()); |
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238 } |
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239 |
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240 void GangWorker::run() { |
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241 initialize(); |
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242 loop(); |
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243 } |
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244 |
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245 void GangWorker::initialize() { |
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246 this->initialize_thread_local_storage(); |
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247 this->record_stack_base_and_size(); |
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248 assert(_gang != NULL, "No gang to run in"); |
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249 os::set_priority(this, NearMaxPriority); |
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250 if (TraceWorkGang) { |
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251 tty->print_cr("Running gang worker for gang %s id %d", |
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252 gang()->name(), id()); |
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253 } |
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254 // The VM thread should not execute here because MutexLocker's are used |
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255 // as (opposed to MutexLockerEx's). |
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256 assert(!Thread::current()->is_VM_thread(), "VM thread should not be part" |
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257 " of a work gang"); |
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258 } |
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259 |
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260 void GangWorker::loop() { |
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261 int previous_sequence_number = 0; |
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262 Monitor* gang_monitor = gang()->monitor(); |
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263 for ( ; /* !terminate() */; ) { |
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264 WorkData data; |
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265 int part; // Initialized below. |
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266 { |
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267 // Grab the gang mutex. |
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268 MutexLocker ml(gang_monitor); |
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269 // Wait for something to do. |
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270 // Polling outside the while { wait } avoids missed notifies |
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271 // in the outer loop. |
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272 gang()->internal_worker_poll(&data); |
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273 if (TraceWorkGang) { |
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274 tty->print("Polled outside for work in gang %s worker %d", |
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275 gang()->name(), id()); |
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276 tty->print(" terminate: %s", |
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277 data.terminate() ? "true" : "false"); |
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278 tty->print(" sequence: %d (prev: %d)", |
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279 data.sequence_number(), previous_sequence_number); |
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280 if (data.task() != NULL) { |
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281 tty->print(" task: %s", data.task()->name()); |
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282 } else { |
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283 tty->print(" task: NULL"); |
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284 } |
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285 tty->cr(); |
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286 } |
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287 for ( ; /* break or return */; ) { |
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288 // Terminate if requested. |
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289 if (data.terminate()) { |
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290 gang()->internal_note_finish(); |
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291 gang_monitor->notify_all(); |
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292 return; |
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293 } |
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294 // Check for new work. |
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295 if ((data.task() != NULL) && |
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296 (data.sequence_number() != previous_sequence_number)) { |
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297 if (gang()->needs_more_workers()) { |
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298 gang()->internal_note_start(); |
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299 gang_monitor->notify_all(); |
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300 part = gang()->started_workers() - 1; |
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301 break; |
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302 } |
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303 } |
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304 // Nothing to do. |
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305 gang_monitor->wait(/* no_safepoint_check */ true); |
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306 gang()->internal_worker_poll(&data); |
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307 if (TraceWorkGang) { |
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308 tty->print("Polled inside for work in gang %s worker %d", |
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309 gang()->name(), id()); |
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310 tty->print(" terminate: %s", |
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311 data.terminate() ? "true" : "false"); |
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312 tty->print(" sequence: %d (prev: %d)", |
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313 data.sequence_number(), previous_sequence_number); |
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314 if (data.task() != NULL) { |
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315 tty->print(" task: %s", data.task()->name()); |
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316 } else { |
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317 tty->print(" task: NULL"); |
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318 } |
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319 tty->cr(); |
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320 } |
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321 } |
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322 // Drop gang mutex. |
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323 } |
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324 if (TraceWorkGang) { |
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325 tty->print("Work for work gang %s id %d task %s part %d", |
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326 gang()->name(), id(), data.task()->name(), part); |
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327 } |
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328 assert(data.task() != NULL, "Got null task"); |
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329 data.task()->work(part); |
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330 { |
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331 if (TraceWorkGang) { |
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332 tty->print("Finish for work gang %s id %d task %s part %d", |
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333 gang()->name(), id(), data.task()->name(), part); |
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334 } |
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335 // Grab the gang mutex. |
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336 MutexLocker ml(gang_monitor); |
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337 gang()->internal_note_finish(); |
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338 // Tell the gang you are done. |
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339 gang_monitor->notify_all(); |
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340 // Drop the gang mutex. |
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341 } |
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342 previous_sequence_number = data.sequence_number(); |
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343 } |
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344 } |
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345 |
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346 bool GangWorker::is_GC_task_thread() const { |
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347 return gang()->are_GC_task_threads(); |
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348 } |
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349 |
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350 bool GangWorker::is_ConcurrentGC_thread() const { |
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351 return gang()->are_ConcurrentGC_threads(); |
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352 } |
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353 |
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354 void GangWorker::print_on(outputStream* st) const { |
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355 st->print("\"%s\" ", name()); |
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356 Thread::print_on(st); |
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357 st->cr(); |
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358 } |
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359 |
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360 // Printing methods |
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361 |
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362 const char* AbstractWorkGang::name() const { |
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363 return _name; |
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364 } |
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365 |
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366 #ifndef PRODUCT |
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367 |
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368 const char* AbstractGangTask::name() const { |
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369 return _name; |
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370 } |
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371 |
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372 #endif /* PRODUCT */ |
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373 |
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374 // FlexibleWorkGang |
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375 |
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376 |
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377 // *** WorkGangBarrierSync |
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378 |
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379 WorkGangBarrierSync::WorkGangBarrierSync() |
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380 : _monitor(Mutex::safepoint, "work gang barrier sync", true), |
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381 _n_workers(0), _n_completed(0), _should_reset(false), _aborted(false) { |
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382 } |
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383 |
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384 WorkGangBarrierSync::WorkGangBarrierSync(uint n_workers, const char* name) |
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385 : _monitor(Mutex::safepoint, name, true), |
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386 _n_workers(n_workers), _n_completed(0), _should_reset(false), _aborted(false) { |
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387 } |
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388 |
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389 void WorkGangBarrierSync::set_n_workers(uint n_workers) { |
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390 _n_workers = n_workers; |
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391 _n_completed = 0; |
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392 _should_reset = false; |
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393 _aborted = false; |
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394 } |
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395 |
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396 bool WorkGangBarrierSync::enter() { |
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397 MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag); |
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398 if (should_reset()) { |
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399 // The should_reset() was set and we are the first worker to enter |
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400 // the sync barrier. We will zero the n_completed() count which |
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401 // effectively resets the barrier. |
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402 zero_completed(); |
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403 set_should_reset(false); |
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404 } |
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405 inc_completed(); |
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406 if (n_completed() == n_workers()) { |
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407 // At this point we would like to reset the barrier to be ready in |
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408 // case it is used again. However, we cannot set n_completed() to |
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409 // 0, even after the notify_all(), given that some other workers |
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410 // might still be waiting for n_completed() to become == |
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411 // n_workers(). So, if we set n_completed() to 0, those workers |
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412 // will get stuck (as they will wake up, see that n_completed() != |
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413 // n_workers() and go back to sleep). Instead, we raise the |
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414 // should_reset() flag and the barrier will be reset the first |
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415 // time a worker enters it again. |
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416 set_should_reset(true); |
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417 monitor()->notify_all(); |
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418 } else { |
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419 while (n_completed() != n_workers() && !aborted()) { |
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420 monitor()->wait(/* no_safepoint_check */ true); |
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421 } |
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422 } |
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423 return !aborted(); |
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424 } |
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425 |
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426 void WorkGangBarrierSync::abort() { |
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427 MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag); |
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428 set_aborted(); |
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429 monitor()->notify_all(); |
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430 } |
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431 |
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432 // SubTasksDone functions. |
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433 |
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434 SubTasksDone::SubTasksDone(uint n) : |
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435 _n_tasks(n), _n_threads(1), _tasks(NULL) { |
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436 _tasks = NEW_C_HEAP_ARRAY(uint, n, mtInternal); |
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437 guarantee(_tasks != NULL, "alloc failure"); |
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438 clear(); |
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439 } |
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440 |
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441 bool SubTasksDone::valid() { |
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442 return _tasks != NULL; |
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443 } |
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444 |
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445 void SubTasksDone::set_n_threads(uint t) { |
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446 assert(_claimed == 0 || _threads_completed == _n_threads, |
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447 "should not be called while tasks are being processed!"); |
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448 _n_threads = (t == 0 ? 1 : t); |
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449 } |
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450 |
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451 void SubTasksDone::clear() { |
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452 for (uint i = 0; i < _n_tasks; i++) { |
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453 _tasks[i] = 0; |
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454 } |
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455 _threads_completed = 0; |
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456 #ifdef ASSERT |
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457 _claimed = 0; |
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458 #endif |
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459 } |
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460 |
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461 bool SubTasksDone::is_task_claimed(uint t) { |
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462 assert(0 <= t && t < _n_tasks, "bad task id."); |
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463 uint old = _tasks[t]; |
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464 if (old == 0) { |
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465 old = Atomic::cmpxchg(1, &_tasks[t], 0); |
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466 } |
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467 assert(_tasks[t] == 1, "What else?"); |
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468 bool res = old != 0; |
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469 #ifdef ASSERT |
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470 if (!res) { |
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471 assert(_claimed < _n_tasks, "Too many tasks claimed; missing clear?"); |
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472 Atomic::inc((volatile jint*) &_claimed); |
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473 } |
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474 #endif |
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475 return res; |
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476 } |
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477 |
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478 void SubTasksDone::all_tasks_completed() { |
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479 jint observed = _threads_completed; |
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480 jint old; |
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481 do { |
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482 old = observed; |
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483 observed = Atomic::cmpxchg(old+1, &_threads_completed, old); |
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484 } while (observed != old); |
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485 // If this was the last thread checking in, clear the tasks. |
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486 if (observed+1 == (jint)_n_threads) clear(); |
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487 } |
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488 |
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489 |
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490 SubTasksDone::~SubTasksDone() { |
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491 if (_tasks != NULL) FREE_C_HEAP_ARRAY(jint, _tasks, mtInternal); |
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492 } |
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493 |
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494 // *** SequentialSubTasksDone |
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495 |
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496 void SequentialSubTasksDone::clear() { |
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497 _n_tasks = _n_claimed = 0; |
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498 _n_threads = _n_completed = 0; |
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499 } |
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500 |
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501 bool SequentialSubTasksDone::valid() { |
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502 return _n_threads > 0; |
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503 } |
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504 |
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505 bool SequentialSubTasksDone::is_task_claimed(uint& t) { |
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506 uint* n_claimed_ptr = &_n_claimed; |
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507 t = *n_claimed_ptr; |
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508 while (t < _n_tasks) { |
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509 jint res = Atomic::cmpxchg(t+1, n_claimed_ptr, t); |
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510 if (res == (jint)t) { |
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511 return false; |
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512 } |
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513 t = *n_claimed_ptr; |
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514 } |
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515 return true; |
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516 } |
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517 |
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518 bool SequentialSubTasksDone::all_tasks_completed() { |
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519 uint* n_completed_ptr = &_n_completed; |
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520 uint complete = *n_completed_ptr; |
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521 while (true) { |
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522 uint res = Atomic::cmpxchg(complete+1, n_completed_ptr, complete); |
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523 if (res == complete) { |
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524 break; |
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525 } |
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526 complete = res; |
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527 } |
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528 if (complete+1 == _n_threads) { |
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529 clear(); |
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530 return true; |
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531 } |
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532 return false; |
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533 } |
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534 |
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535 bool FreeIdSet::_stat_init = false; |
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536 FreeIdSet* FreeIdSet::_sets[NSets]; |
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537 bool FreeIdSet::_safepoint; |
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538 |
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539 FreeIdSet::FreeIdSet(int sz, Monitor* mon) : |
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540 _sz(sz), _mon(mon), _hd(0), _waiters(0), _index(-1), _claimed(0) |
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541 { |
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542 _ids = NEW_C_HEAP_ARRAY(int, sz, mtInternal); |
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543 for (int i = 0; i < sz; i++) _ids[i] = i+1; |
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544 _ids[sz-1] = end_of_list; // end of list. |
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545 if (_stat_init) { |
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546 for (int j = 0; j < NSets; j++) _sets[j] = NULL; |
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547 _stat_init = true; |
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548 } |
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549 // Add to sets. (This should happen while the system is still single-threaded.) |
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550 for (int j = 0; j < NSets; j++) { |
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551 if (_sets[j] == NULL) { |
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552 _sets[j] = this; |
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553 _index = j; |
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554 break; |
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555 } |
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556 } |
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557 guarantee(_index != -1, "Too many FreeIdSets in use!"); |
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558 } |
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559 |
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560 FreeIdSet::~FreeIdSet() { |
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561 _sets[_index] = NULL; |
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562 FREE_C_HEAP_ARRAY(int, _ids, mtInternal); |
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563 } |
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564 |
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565 void FreeIdSet::set_safepoint(bool b) { |
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566 _safepoint = b; |
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567 if (b) { |
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568 for (int j = 0; j < NSets; j++) { |
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569 if (_sets[j] != NULL && _sets[j]->_waiters > 0) { |
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570 Monitor* mon = _sets[j]->_mon; |
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571 mon->lock_without_safepoint_check(); |
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572 mon->notify_all(); |
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573 mon->unlock(); |
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574 } |
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575 } |
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576 } |
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577 } |
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578 |
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579 #define FID_STATS 0 |
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580 |
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581 int FreeIdSet::claim_par_id() { |
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582 #if FID_STATS |
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583 thread_t tslf = thr_self(); |
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584 tty->print("claim_par_id[%d]: sz = %d, claimed = %d\n", tslf, _sz, _claimed); |
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585 #endif |
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586 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); |
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587 while (!_safepoint && _hd == end_of_list) { |
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588 _waiters++; |
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589 #if FID_STATS |
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590 if (_waiters > 5) { |
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591 tty->print("claim_par_id waiting[%d]: %d waiters, %d claimed.\n", |
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592 tslf, _waiters, _claimed); |
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593 } |
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594 #endif |
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595 _mon->wait(Mutex::_no_safepoint_check_flag); |
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596 _waiters--; |
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597 } |
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598 if (_hd == end_of_list) { |
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599 #if FID_STATS |
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600 tty->print("claim_par_id[%d]: returning EOL.\n", tslf); |
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601 #endif |
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602 return -1; |
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603 } else { |
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604 int res = _hd; |
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605 _hd = _ids[res]; |
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606 _ids[res] = claimed; // For debugging. |
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607 _claimed++; |
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608 #if FID_STATS |
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609 tty->print("claim_par_id[%d]: returning %d, claimed = %d.\n", |
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610 tslf, res, _claimed); |
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611 #endif |
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612 return res; |
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613 } |
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614 } |
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615 |
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616 bool FreeIdSet::claim_perm_id(int i) { |
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617 assert(0 <= i && i < _sz, "Out of range."); |
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618 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); |
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619 int prev = end_of_list; |
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620 int cur = _hd; |
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621 while (cur != end_of_list) { |
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622 if (cur == i) { |
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623 if (prev == end_of_list) { |
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624 _hd = _ids[cur]; |
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625 } else { |
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626 _ids[prev] = _ids[cur]; |
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627 } |
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628 _ids[cur] = claimed; |
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629 _claimed++; |
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630 return true; |
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631 } else { |
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632 prev = cur; |
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633 cur = _ids[cur]; |
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634 } |
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635 } |
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636 return false; |
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637 |
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638 } |
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639 |
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640 void FreeIdSet::release_par_id(int id) { |
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641 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); |
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642 assert(_ids[id] == claimed, "Precondition."); |
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643 _ids[id] = _hd; |
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644 _hd = id; |
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645 _claimed--; |
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646 #if FID_STATS |
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647 tty->print("[%d] release_par_id(%d), waiters =%d, claimed = %d.\n", |
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648 thr_self(), id, _waiters, _claimed); |
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649 #endif |
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650 if (_waiters > 0) |
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651 // Notify all would be safer, but this is OK, right? |
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652 _mon->notify_all(); |
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653 } |