Mercurial > hg > truffle
annotate src/share/vm/runtime/vmThread.cpp @ 1490:f03d0a26bf83
6888954: argument formatting for assert() and friends
Reviewed-by: kvn, twisti, apetrusenko, never, dcubed
| author | jcoomes |
|---|---|
| date | Thu, 22 Apr 2010 13:23:15 -0700 |
| parents | cff162798819 |
| children | c18cbe5936b8 |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright 1998-2010 Sun Microsystems, Inc. All Rights Reserved. |
| 0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
| 19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
| 20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
| 21 * have any questions. | |
| 22 * | |
| 23 */ | |
| 24 | |
| 25 # include "incls/_precompiled.incl" | |
| 26 # include "incls/_vmThread.cpp.incl" | |
| 27 | |
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28 HS_DTRACE_PROBE_DECL3(hotspot, vmops__request, char *, uintptr_t, int); |
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29 HS_DTRACE_PROBE_DECL3(hotspot, vmops__begin, char *, uintptr_t, int); |
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30 HS_DTRACE_PROBE_DECL3(hotspot, vmops__end, char *, uintptr_t, int); |
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31 |
| 0 | 32 // Dummy VM operation to act as first element in our circular double-linked list |
| 33 class VM_Dummy: public VM_Operation { | |
| 34 VMOp_Type type() const { return VMOp_Dummy; } | |
| 35 void doit() {}; | |
| 36 }; | |
| 37 | |
| 38 VMOperationQueue::VMOperationQueue() { | |
| 39 // The queue is a circular doubled-linked list, which always contains | |
| 40 // one element (i.e., one element means empty). | |
| 41 for(int i = 0; i < nof_priorities; i++) { | |
| 42 _queue_length[i] = 0; | |
| 43 _queue_counter = 0; | |
| 44 _queue[i] = new VM_Dummy(); | |
| 45 _queue[i]->set_next(_queue[i]); | |
| 46 _queue[i]->set_prev(_queue[i]); | |
| 47 } | |
| 48 _drain_list = NULL; | |
| 49 } | |
| 50 | |
| 51 | |
| 52 bool VMOperationQueue::queue_empty(int prio) { | |
| 53 // It is empty if there is exactly one element | |
| 54 bool empty = (_queue[prio] == _queue[prio]->next()); | |
| 55 assert( (_queue_length[prio] == 0 && empty) || | |
| 56 (_queue_length[prio] > 0 && !empty), "sanity check"); | |
| 57 return _queue_length[prio] == 0; | |
| 58 } | |
| 59 | |
| 60 // Inserts an element to the right of the q element | |
| 61 void VMOperationQueue::insert(VM_Operation* q, VM_Operation* n) { | |
| 62 assert(q->next()->prev() == q && q->prev()->next() == q, "sanity check"); | |
| 63 n->set_prev(q); | |
| 64 n->set_next(q->next()); | |
| 65 q->next()->set_prev(n); | |
| 66 q->set_next(n); | |
| 67 } | |
| 68 | |
| 69 void VMOperationQueue::queue_add_front(int prio, VM_Operation *op) { | |
| 70 _queue_length[prio]++; | |
| 71 insert(_queue[prio]->next(), op); | |
| 72 } | |
| 73 | |
| 74 void VMOperationQueue::queue_add_back(int prio, VM_Operation *op) { | |
| 75 _queue_length[prio]++; | |
| 76 insert(_queue[prio]->prev(), op); | |
| 77 } | |
| 78 | |
| 79 | |
| 80 void VMOperationQueue::unlink(VM_Operation* q) { | |
| 81 assert(q->next()->prev() == q && q->prev()->next() == q, "sanity check"); | |
| 82 q->prev()->set_next(q->next()); | |
| 83 q->next()->set_prev(q->prev()); | |
| 84 } | |
| 85 | |
| 86 VM_Operation* VMOperationQueue::queue_remove_front(int prio) { | |
| 87 if (queue_empty(prio)) return NULL; | |
| 88 assert(_queue_length[prio] >= 0, "sanity check"); | |
| 89 _queue_length[prio]--; | |
| 90 VM_Operation* r = _queue[prio]->next(); | |
| 91 assert(r != _queue[prio], "cannot remove base element"); | |
| 92 unlink(r); | |
| 93 return r; | |
| 94 } | |
| 95 | |
| 96 VM_Operation* VMOperationQueue::queue_drain(int prio) { | |
| 97 if (queue_empty(prio)) return NULL; | |
| 98 DEBUG_ONLY(int length = _queue_length[prio];); | |
| 99 assert(length >= 0, "sanity check"); | |
| 100 _queue_length[prio] = 0; | |
| 101 VM_Operation* r = _queue[prio]->next(); | |
| 102 assert(r != _queue[prio], "cannot remove base element"); | |
| 103 // remove links to base element from head and tail | |
| 104 r->set_prev(NULL); | |
| 105 _queue[prio]->prev()->set_next(NULL); | |
| 106 // restore queue to empty state | |
| 107 _queue[prio]->set_next(_queue[prio]); | |
| 108 _queue[prio]->set_prev(_queue[prio]); | |
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109 assert(queue_empty(prio), "drain corrupted queue"); |
| 0 | 110 #ifdef DEBUG |
| 111 int len = 0; | |
| 112 VM_Operation* cur; | |
| 113 for(cur = r; cur != NULL; cur=cur->next()) len++; | |
| 114 assert(len == length, "drain lost some ops"); | |
| 115 #endif | |
| 116 return r; | |
| 117 } | |
| 118 | |
| 119 void VMOperationQueue::queue_oops_do(int queue, OopClosure* f) { | |
| 120 VM_Operation* cur = _queue[queue]; | |
| 121 cur = cur->next(); | |
| 122 while (cur != _queue[queue]) { | |
| 123 cur->oops_do(f); | |
| 124 cur = cur->next(); | |
| 125 } | |
| 126 } | |
| 127 | |
| 128 void VMOperationQueue::drain_list_oops_do(OopClosure* f) { | |
| 129 VM_Operation* cur = _drain_list; | |
| 130 while (cur != NULL) { | |
| 131 cur->oops_do(f); | |
| 132 cur = cur->next(); | |
| 133 } | |
| 134 } | |
| 135 | |
| 136 //----------------------------------------------------------------- | |
| 137 // High-level interface | |
| 138 bool VMOperationQueue::add(VM_Operation *op) { | |
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139 |
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140 HS_DTRACE_PROBE3(hotspot, vmops__request, op->name(), strlen(op->name()), |
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141 op->evaluation_mode()); |
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142 |
| 0 | 143 // Encapsulates VM queue policy. Currently, that |
| 144 // only involves putting them on the right list | |
| 145 if (op->evaluate_at_safepoint()) { | |
| 146 queue_add_back(SafepointPriority, op); | |
| 147 return true; | |
| 148 } | |
| 149 | |
| 150 queue_add_back(MediumPriority, op); | |
| 151 return true; | |
| 152 } | |
| 153 | |
| 154 VM_Operation* VMOperationQueue::remove_next() { | |
| 155 // Assuming VMOperation queue is two-level priority queue. If there are | |
| 156 // more than two priorities, we need a different scheduling algorithm. | |
| 157 assert(SafepointPriority == 0 && MediumPriority == 1 && nof_priorities == 2, | |
| 158 "current algorithm does not work"); | |
| 159 | |
| 160 // simple counter based scheduling to prevent starvation of lower priority | |
| 161 // queue. -- see 4390175 | |
| 162 int high_prio, low_prio; | |
| 163 if (_queue_counter++ < 10) { | |
| 164 high_prio = SafepointPriority; | |
| 165 low_prio = MediumPriority; | |
| 166 } else { | |
| 167 _queue_counter = 0; | |
| 168 high_prio = MediumPriority; | |
| 169 low_prio = SafepointPriority; | |
| 170 } | |
| 171 | |
| 172 return queue_remove_front(queue_empty(high_prio) ? low_prio : high_prio); | |
| 173 } | |
| 174 | |
| 175 void VMOperationQueue::oops_do(OopClosure* f) { | |
| 176 for(int i = 0; i < nof_priorities; i++) { | |
| 177 queue_oops_do(i, f); | |
| 178 } | |
| 179 drain_list_oops_do(f); | |
| 180 } | |
| 181 | |
| 182 | |
| 183 //------------------------------------------------------------------------------------------------------------------ | |
| 184 // Implementation of VMThread stuff | |
| 185 | |
| 186 bool VMThread::_should_terminate = false; | |
| 187 bool VMThread::_terminated = false; | |
| 188 Monitor* VMThread::_terminate_lock = NULL; | |
| 189 VMThread* VMThread::_vm_thread = NULL; | |
| 190 VM_Operation* VMThread::_cur_vm_operation = NULL; | |
| 191 VMOperationQueue* VMThread::_vm_queue = NULL; | |
| 192 PerfCounter* VMThread::_perf_accumulated_vm_operation_time = NULL; | |
| 193 | |
| 194 | |
| 195 void VMThread::create() { | |
| 196 assert(vm_thread() == NULL, "we can only allocate one VMThread"); | |
| 197 _vm_thread = new VMThread(); | |
| 198 | |
| 199 // Create VM operation queue | |
| 200 _vm_queue = new VMOperationQueue(); | |
| 201 guarantee(_vm_queue != NULL, "just checking"); | |
| 202 | |
| 203 _terminate_lock = new Monitor(Mutex::safepoint, "VMThread::_terminate_lock", true); | |
| 204 | |
| 205 if (UsePerfData) { | |
| 206 // jvmstat performance counters | |
| 207 Thread* THREAD = Thread::current(); | |
| 208 _perf_accumulated_vm_operation_time = | |
| 209 PerfDataManager::create_counter(SUN_THREADS, "vmOperationTime", | |
| 210 PerfData::U_Ticks, CHECK); | |
| 211 } | |
| 212 } | |
| 213 | |
| 214 | |
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215 VMThread::VMThread() : NamedThread() { |
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216 set_name("VM Thread"); |
| 0 | 217 } |
| 218 | |
| 219 void VMThread::destroy() { | |
| 220 if (_vm_thread != NULL) { | |
| 221 delete _vm_thread; | |
| 222 _vm_thread = NULL; // VM thread is gone | |
| 223 } | |
| 224 } | |
| 225 | |
| 226 void VMThread::run() { | |
| 227 assert(this == vm_thread(), "check"); | |
| 228 | |
| 229 this->initialize_thread_local_storage(); | |
| 230 this->record_stack_base_and_size(); | |
| 231 // Notify_lock wait checks on active_handles() to rewait in | |
| 232 // case of spurious wakeup, it should wait on the last | |
| 233 // value set prior to the notify | |
| 234 this->set_active_handles(JNIHandleBlock::allocate_block()); | |
| 235 | |
| 236 { | |
| 237 MutexLocker ml(Notify_lock); | |
| 238 Notify_lock->notify(); | |
| 239 } | |
| 240 // Notify_lock is destroyed by Threads::create_vm() | |
| 241 | |
| 242 int prio = (VMThreadPriority == -1) | |
| 243 ? os::java_to_os_priority[NearMaxPriority] | |
| 244 : VMThreadPriority; | |
| 245 // Note that I cannot call os::set_priority because it expects Java | |
| 246 // priorities and I am *explicitly* using OS priorities so that it's | |
| 247 // possible to set the VM thread priority higher than any Java thread. | |
| 248 os::set_native_priority( this, prio ); | |
| 249 | |
| 250 // Wait for VM_Operations until termination | |
| 251 this->loop(); | |
| 252 | |
| 253 // Note the intention to exit before safepointing. | |
| 254 // 6295565 This has the effect of waiting for any large tty | |
| 255 // outputs to finish. | |
| 256 if (xtty != NULL) { | |
| 257 ttyLocker ttyl; | |
| 258 xtty->begin_elem("destroy_vm"); | |
| 259 xtty->stamp(); | |
| 260 xtty->end_elem(); | |
| 261 assert(should_terminate(), "termination flag must be set"); | |
| 262 } | |
| 263 | |
| 264 // 4526887 let VM thread exit at Safepoint | |
| 265 SafepointSynchronize::begin(); | |
| 266 | |
| 267 if (VerifyBeforeExit) { | |
| 268 HandleMark hm(VMThread::vm_thread()); | |
| 269 // Among other things, this ensures that Eden top is correct. | |
| 270 Universe::heap()->prepare_for_verify(); | |
| 271 os::check_heap(); | |
| 272 Universe::verify(true, true); // Silent verification to not polute normal output | |
| 273 } | |
| 274 | |
| 275 CompileBroker::set_should_block(); | |
| 276 | |
| 277 // wait for threads (compiler threads or daemon threads) in the | |
| 278 // _thread_in_native state to block. | |
| 279 VM_Exit::wait_for_threads_in_native_to_block(); | |
| 280 | |
| 281 // signal other threads that VM process is gone | |
| 282 { | |
| 283 // Note: we must have the _no_safepoint_check_flag. Mutex::lock() allows | |
| 284 // VM thread to enter any lock at Safepoint as long as its _owner is NULL. | |
| 285 // If that happens after _terminate_lock->wait() has unset _owner | |
| 286 // but before it actually drops the lock and waits, the notification below | |
| 287 // may get lost and we will have a hang. To avoid this, we need to use | |
| 288 // Mutex::lock_without_safepoint_check(). | |
| 289 MutexLockerEx ml(_terminate_lock, Mutex::_no_safepoint_check_flag); | |
| 290 _terminated = true; | |
| 291 _terminate_lock->notify(); | |
| 292 } | |
| 293 | |
| 294 // Deletion must be done synchronously by the JNI DestroyJavaVM thread | |
| 295 // so that the VMThread deletion completes before the main thread frees | |
| 296 // up the CodeHeap. | |
| 297 | |
| 298 } | |
| 299 | |
| 300 | |
| 301 // Notify the VMThread that the last non-daemon JavaThread has terminated, | |
| 302 // and wait until operation is performed. | |
| 303 void VMThread::wait_for_vm_thread_exit() { | |
| 304 { MutexLocker mu(VMOperationQueue_lock); | |
| 305 _should_terminate = true; | |
| 306 VMOperationQueue_lock->notify(); | |
| 307 } | |
| 308 | |
| 309 // Note: VM thread leaves at Safepoint. We are not stopped by Safepoint | |
| 310 // because this thread has been removed from the threads list. But anything | |
| 311 // that could get blocked by Safepoint should not be used after this point, | |
| 312 // otherwise we will hang, since there is no one can end the safepoint. | |
| 313 | |
| 314 // Wait until VM thread is terminated | |
| 315 // Note: it should be OK to use Terminator_lock here. But this is called | |
| 316 // at a very delicate time (VM shutdown) and we are operating in non- VM | |
| 317 // thread at Safepoint. It's safer to not share lock with other threads. | |
| 318 { MutexLockerEx ml(_terminate_lock, Mutex::_no_safepoint_check_flag); | |
| 319 while(!VMThread::is_terminated()) { | |
| 320 _terminate_lock->wait(Mutex::_no_safepoint_check_flag); | |
| 321 } | |
| 322 } | |
| 323 } | |
| 324 | |
| 325 void VMThread::print_on(outputStream* st) const { | |
| 326 st->print("\"%s\" ", name()); | |
| 327 Thread::print_on(st); | |
| 328 st->cr(); | |
| 329 } | |
| 330 | |
| 331 void VMThread::evaluate_operation(VM_Operation* op) { | |
| 332 ResourceMark rm; | |
| 333 | |
| 334 { | |
| 335 PerfTraceTime vm_op_timer(perf_accumulated_vm_operation_time()); | |
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336 HS_DTRACE_PROBE3(hotspot, vmops__begin, op->name(), strlen(op->name()), |
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337 op->evaluation_mode()); |
| 0 | 338 op->evaluate(); |
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339 HS_DTRACE_PROBE3(hotspot, vmops__end, op->name(), strlen(op->name()), |
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340 op->evaluation_mode()); |
| 0 | 341 } |
| 342 | |
| 343 // Last access of info in _cur_vm_operation! | |
| 344 bool c_heap_allocated = op->is_cheap_allocated(); | |
| 345 | |
| 346 // Mark as completed | |
| 347 if (!op->evaluate_concurrently()) { | |
| 348 op->calling_thread()->increment_vm_operation_completed_count(); | |
| 349 } | |
| 350 // It is unsafe to access the _cur_vm_operation after the 'increment_vm_operation_completed_count' call, | |
| 351 // since if it is stack allocated the calling thread might have deallocated | |
| 352 if (c_heap_allocated) { | |
| 353 delete _cur_vm_operation; | |
| 354 } | |
| 355 } | |
| 356 | |
| 357 | |
| 358 void VMThread::loop() { | |
| 359 assert(_cur_vm_operation == NULL, "no current one should be executing"); | |
| 360 | |
| 361 while(true) { | |
| 362 VM_Operation* safepoint_ops = NULL; | |
| 363 // | |
| 364 // Wait for VM operation | |
| 365 // | |
| 366 // use no_safepoint_check to get lock without attempting to "sneak" | |
| 367 { MutexLockerEx mu_queue(VMOperationQueue_lock, | |
| 368 Mutex::_no_safepoint_check_flag); | |
| 369 | |
| 370 // Look for new operation | |
| 371 assert(_cur_vm_operation == NULL, "no current one should be executing"); | |
| 372 _cur_vm_operation = _vm_queue->remove_next(); | |
| 373 | |
| 374 // Stall time tracking code | |
| 375 if (PrintVMQWaitTime && _cur_vm_operation != NULL && | |
| 376 !_cur_vm_operation->evaluate_concurrently()) { | |
| 377 long stall = os::javaTimeMillis() - _cur_vm_operation->timestamp(); | |
| 378 if (stall > 0) | |
| 379 tty->print_cr("%s stall: %Ld", _cur_vm_operation->name(), stall); | |
| 380 } | |
| 381 | |
| 382 while (!should_terminate() && _cur_vm_operation == NULL) { | |
| 383 // wait with a timeout to guarantee safepoints at regular intervals | |
| 384 bool timedout = | |
| 385 VMOperationQueue_lock->wait(Mutex::_no_safepoint_check_flag, | |
| 386 GuaranteedSafepointInterval); | |
| 387 | |
| 388 // Support for self destruction | |
| 389 if ((SelfDestructTimer != 0) && !is_error_reported() && | |
| 390 (os::elapsedTime() > SelfDestructTimer * 60)) { | |
| 391 tty->print_cr("VM self-destructed"); | |
| 392 exit(-1); | |
| 393 } | |
| 394 | |
| 395 if (timedout && (SafepointALot || | |
| 396 SafepointSynchronize::is_cleanup_needed())) { | |
| 397 MutexUnlockerEx mul(VMOperationQueue_lock, | |
| 398 Mutex::_no_safepoint_check_flag); | |
| 399 // Force a safepoint since we have not had one for at least | |
| 400 // 'GuaranteedSafepointInterval' milliseconds. This will run all | |
| 401 // the clean-up processing that needs to be done regularly at a | |
| 402 // safepoint | |
| 403 SafepointSynchronize::begin(); | |
| 404 #ifdef ASSERT | |
| 405 if (GCALotAtAllSafepoints) InterfaceSupport::check_gc_alot(); | |
| 406 #endif | |
| 407 SafepointSynchronize::end(); | |
| 408 } | |
| 409 _cur_vm_operation = _vm_queue->remove_next(); | |
| 410 | |
| 411 // If we are at a safepoint we will evaluate all the operations that | |
| 412 // follow that also require a safepoint | |
| 413 if (_cur_vm_operation != NULL && | |
| 414 _cur_vm_operation->evaluate_at_safepoint()) { | |
| 415 safepoint_ops = _vm_queue->drain_at_safepoint_priority(); | |
| 416 } | |
| 417 } | |
| 418 | |
| 419 if (should_terminate()) break; | |
| 420 } // Release mu_queue_lock | |
| 421 | |
| 422 // | |
| 423 // Execute VM operation | |
| 424 // | |
| 425 { HandleMark hm(VMThread::vm_thread()); | |
| 426 | |
| 427 EventMark em("Executing VM operation: %s", vm_operation()->name()); | |
| 428 assert(_cur_vm_operation != NULL, "we should have found an operation to execute"); | |
| 429 | |
| 430 // Give the VM thread an extra quantum. Jobs tend to be bursty and this | |
| 431 // helps the VM thread to finish up the job. | |
| 432 // FIXME: When this is enabled and there are many threads, this can degrade | |
| 433 // performance significantly. | |
| 434 if( VMThreadHintNoPreempt ) | |
| 435 os::hint_no_preempt(); | |
| 436 | |
| 437 // If we are at a safepoint we will evaluate all the operations that | |
| 438 // follow that also require a safepoint | |
| 439 if (_cur_vm_operation->evaluate_at_safepoint()) { | |
| 440 | |
| 441 _vm_queue->set_drain_list(safepoint_ops); // ensure ops can be scanned | |
| 442 | |
| 443 SafepointSynchronize::begin(); | |
| 444 evaluate_operation(_cur_vm_operation); | |
| 445 // now process all queued safepoint ops, iteratively draining | |
| 446 // the queue until there are none left | |
| 447 do { | |
| 448 _cur_vm_operation = safepoint_ops; | |
| 449 if (_cur_vm_operation != NULL) { | |
| 450 do { | |
| 451 // evaluate_operation deletes the op object so we have | |
| 452 // to grab the next op now | |
| 453 VM_Operation* next = _cur_vm_operation->next(); | |
| 454 _vm_queue->set_drain_list(next); | |
| 455 evaluate_operation(_cur_vm_operation); | |
| 456 _cur_vm_operation = next; | |
| 457 if (PrintSafepointStatistics) { | |
| 458 SafepointSynchronize::inc_vmop_coalesced_count(); | |
| 459 } | |
| 460 } while (_cur_vm_operation != NULL); | |
| 461 } | |
| 462 // There is a chance that a thread enqueued a safepoint op | |
| 463 // since we released the op-queue lock and initiated the safepoint. | |
| 464 // So we drain the queue again if there is anything there, as an | |
| 465 // optimization to try and reduce the number of safepoints. | |
| 466 // As the safepoint synchronizes us with JavaThreads we will see | |
| 467 // any enqueue made by a JavaThread, but the peek will not | |
| 468 // necessarily detect a concurrent enqueue by a GC thread, but | |
| 469 // that simply means the op will wait for the next major cycle of the | |
| 470 // VMThread - just as it would if the GC thread lost the race for | |
| 471 // the lock. | |
| 472 if (_vm_queue->peek_at_safepoint_priority()) { | |
| 473 // must hold lock while draining queue | |
| 474 MutexLockerEx mu_queue(VMOperationQueue_lock, | |
| 475 Mutex::_no_safepoint_check_flag); | |
| 476 safepoint_ops = _vm_queue->drain_at_safepoint_priority(); | |
| 477 } else { | |
| 478 safepoint_ops = NULL; | |
| 479 } | |
| 480 } while(safepoint_ops != NULL); | |
| 481 | |
| 482 _vm_queue->set_drain_list(NULL); | |
| 483 | |
| 484 // Complete safepoint synchronization | |
| 485 SafepointSynchronize::end(); | |
| 486 | |
| 487 } else { // not a safepoint operation | |
| 488 if (TraceLongCompiles) { | |
| 489 elapsedTimer t; | |
| 490 t.start(); | |
| 491 evaluate_operation(_cur_vm_operation); | |
| 492 t.stop(); | |
| 493 double secs = t.seconds(); | |
| 494 if (secs * 1e3 > LongCompileThreshold) { | |
| 495 // XXX - _cur_vm_operation should not be accessed after | |
| 496 // the completed count has been incremented; the waiting | |
| 497 // thread may have already freed this memory. | |
| 498 tty->print_cr("vm %s: %3.7f secs]", _cur_vm_operation->name(), secs); | |
| 499 } | |
| 500 } else { | |
| 501 evaluate_operation(_cur_vm_operation); | |
| 502 } | |
| 503 | |
| 504 _cur_vm_operation = NULL; | |
| 505 } | |
| 506 } | |
| 507 | |
| 508 // | |
| 509 // Notify (potential) waiting Java thread(s) - lock without safepoint | |
| 510 // check so that sneaking is not possible | |
| 511 { MutexLockerEx mu(VMOperationRequest_lock, | |
| 512 Mutex::_no_safepoint_check_flag); | |
| 513 VMOperationRequest_lock->notify_all(); | |
| 514 } | |
| 515 | |
| 516 // | |
| 517 // We want to make sure that we get to a safepoint regularly. | |
| 518 // | |
| 519 if (SafepointALot || SafepointSynchronize::is_cleanup_needed()) { | |
| 520 long interval = SafepointSynchronize::last_non_safepoint_interval(); | |
| 521 bool max_time_exceeded = GuaranteedSafepointInterval != 0 && (interval > GuaranteedSafepointInterval); | |
| 522 if (SafepointALot || max_time_exceeded) { | |
| 523 HandleMark hm(VMThread::vm_thread()); | |
| 524 SafepointSynchronize::begin(); | |
| 525 SafepointSynchronize::end(); | |
| 526 } | |
| 527 } | |
| 528 } | |
| 529 } | |
| 530 | |
| 531 void VMThread::execute(VM_Operation* op) { | |
| 532 Thread* t = Thread::current(); | |
| 533 | |
| 534 if (!t->is_VM_thread()) { | |
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535 SkipGCALot sgcalot(t); // avoid re-entrant attempts to gc-a-lot |
| 0 | 536 // JavaThread or WatcherThread |
| 537 t->check_for_valid_safepoint_state(true); | |
| 538 | |
| 539 // New request from Java thread, evaluate prologue | |
| 540 if (!op->doit_prologue()) { | |
| 541 return; // op was cancelled | |
| 542 } | |
| 543 | |
| 544 // Setup VM_operations for execution | |
| 545 op->set_calling_thread(t, Thread::get_priority(t)); | |
| 546 | |
| 547 // It does not make sense to execute the epilogue, if the VM operation object is getting | |
| 548 // deallocated by the VM thread. | |
| 549 bool concurrent = op->evaluate_concurrently(); | |
| 550 bool execute_epilog = !op->is_cheap_allocated(); | |
| 551 assert(!concurrent || op->is_cheap_allocated(), "concurrent => cheap_allocated"); | |
| 552 | |
| 553 // Get ticket number for non-concurrent VM operations | |
| 554 int ticket = 0; | |
| 555 if (!concurrent) { | |
| 556 ticket = t->vm_operation_ticket(); | |
| 557 } | |
| 558 | |
| 559 // Add VM operation to list of waiting threads. We are guaranteed not to block while holding the | |
| 560 // VMOperationQueue_lock, so we can block without a safepoint check. This allows vm operation requests | |
| 561 // to be queued up during a safepoint synchronization. | |
| 562 { | |
| 563 VMOperationQueue_lock->lock_without_safepoint_check(); | |
| 564 bool ok = _vm_queue->add(op); | |
| 565 op->set_timestamp(os::javaTimeMillis()); | |
| 566 VMOperationQueue_lock->notify(); | |
| 567 VMOperationQueue_lock->unlock(); | |
| 568 // VM_Operation got skipped | |
| 569 if (!ok) { | |
| 570 assert(concurrent, "can only skip concurrent tasks"); | |
| 571 if (op->is_cheap_allocated()) delete op; | |
| 572 return; | |
| 573 } | |
| 574 } | |
| 575 | |
| 576 if (!concurrent) { | |
| 577 // Wait for completion of request (non-concurrent) | |
| 578 // Note: only a JavaThread triggers the safepoint check when locking | |
| 579 MutexLocker mu(VMOperationRequest_lock); | |
| 580 while(t->vm_operation_completed_count() < ticket) { | |
| 581 VMOperationRequest_lock->wait(!t->is_Java_thread()); | |
| 582 } | |
| 583 } | |
| 584 | |
| 585 if (execute_epilog) { | |
| 586 op->doit_epilogue(); | |
| 587 } | |
| 588 } else { | |
| 589 // invoked by VM thread; usually nested VM operation | |
| 590 assert(t->is_VM_thread(), "must be a VM thread"); | |
| 591 VM_Operation* prev_vm_operation = vm_operation(); | |
| 592 if (prev_vm_operation != NULL) { | |
| 593 // Check the VM operation allows nested VM operation. This normally not the case, e.g., the compiler | |
| 594 // does not allow nested scavenges or compiles. | |
| 595 if (!prev_vm_operation->allow_nested_vm_operations()) { | |
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596 fatal(err_msg("Nested VM operation %s requested by operation %s", |
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597 op->name(), vm_operation()->name())); |
| 0 | 598 } |
| 599 op->set_calling_thread(prev_vm_operation->calling_thread(), prev_vm_operation->priority()); | |
| 600 } | |
| 601 | |
| 602 EventMark em("Executing %s VM operation: %s", prev_vm_operation ? "nested" : "", op->name()); | |
| 603 | |
| 604 // Release all internal handles after operation is evaluated | |
| 605 HandleMark hm(t); | |
| 606 _cur_vm_operation = op; | |
| 607 | |
| 608 if (op->evaluate_at_safepoint() && !SafepointSynchronize::is_at_safepoint()) { | |
| 609 SafepointSynchronize::begin(); | |
| 610 op->evaluate(); | |
| 611 SafepointSynchronize::end(); | |
| 612 } else { | |
| 613 op->evaluate(); | |
| 614 } | |
| 615 | |
| 616 // Free memory if needed | |
| 617 if (op->is_cheap_allocated()) delete op; | |
| 618 | |
| 619 _cur_vm_operation = prev_vm_operation; | |
| 620 } | |
| 621 } | |
| 622 | |
| 623 | |
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624 void VMThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { |
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625 Thread::oops_do(f, cf); |
| 0 | 626 _vm_queue->oops_do(f); |
| 627 } | |
| 628 | |
| 629 //------------------------------------------------------------------------------------------------------------------ | |
| 630 #ifndef PRODUCT | |
| 631 | |
| 632 void VMOperationQueue::verify_queue(int prio) { | |
| 633 // Check that list is correctly linked | |
| 634 int length = _queue_length[prio]; | |
| 635 VM_Operation *cur = _queue[prio]; | |
| 636 int i; | |
| 637 | |
| 638 // Check forward links | |
| 639 for(i = 0; i < length; i++) { | |
| 640 cur = cur->next(); | |
| 641 assert(cur != _queue[prio], "list to short (forward)"); | |
| 642 } | |
| 643 assert(cur->next() == _queue[prio], "list to long (forward)"); | |
| 644 | |
| 645 // Check backwards links | |
| 646 cur = _queue[prio]; | |
| 647 for(i = 0; i < length; i++) { | |
| 648 cur = cur->prev(); | |
| 649 assert(cur != _queue[prio], "list to short (backwards)"); | |
| 650 } | |
| 651 assert(cur->prev() == _queue[prio], "list to long (backwards)"); | |
| 652 } | |
| 653 | |
| 654 #endif | |
| 655 | |
| 656 void VMThread::verify() { | |
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657 oops_do(&VerifyOopClosure::verify_oop, NULL); |
| 0 | 658 } |