Mercurial > hg > truffle
annotate src/share/vm/runtime/vmThread.cpp @ 1144:9b9c1ee9b3f6
Merge
author | iveresov |
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date | Wed, 06 Jan 2010 22:21:39 -0800 |
parents | 547f81740344 |
children | 8859772195c6 |
rev | line source |
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0 | 1 /* |
844 | 2 * Copyright 1998-2009 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 | |
28 // Dummy VM operation to act as first element in our circular double-linked list | |
29 class VM_Dummy: public VM_Operation { | |
30 VMOp_Type type() const { return VMOp_Dummy; } | |
31 void doit() {}; | |
32 }; | |
33 | |
34 VMOperationQueue::VMOperationQueue() { | |
35 // The queue is a circular doubled-linked list, which always contains | |
36 // one element (i.e., one element means empty). | |
37 for(int i = 0; i < nof_priorities; i++) { | |
38 _queue_length[i] = 0; | |
39 _queue_counter = 0; | |
40 _queue[i] = new VM_Dummy(); | |
41 _queue[i]->set_next(_queue[i]); | |
42 _queue[i]->set_prev(_queue[i]); | |
43 } | |
44 _drain_list = NULL; | |
45 } | |
46 | |
47 | |
48 bool VMOperationQueue::queue_empty(int prio) { | |
49 // It is empty if there is exactly one element | |
50 bool empty = (_queue[prio] == _queue[prio]->next()); | |
51 assert( (_queue_length[prio] == 0 && empty) || | |
52 (_queue_length[prio] > 0 && !empty), "sanity check"); | |
53 return _queue_length[prio] == 0; | |
54 } | |
55 | |
56 // Inserts an element to the right of the q element | |
57 void VMOperationQueue::insert(VM_Operation* q, VM_Operation* n) { | |
58 assert(q->next()->prev() == q && q->prev()->next() == q, "sanity check"); | |
59 n->set_prev(q); | |
60 n->set_next(q->next()); | |
61 q->next()->set_prev(n); | |
62 q->set_next(n); | |
63 } | |
64 | |
65 void VMOperationQueue::queue_add_front(int prio, VM_Operation *op) { | |
66 _queue_length[prio]++; | |
67 insert(_queue[prio]->next(), op); | |
68 } | |
69 | |
70 void VMOperationQueue::queue_add_back(int prio, VM_Operation *op) { | |
71 _queue_length[prio]++; | |
72 insert(_queue[prio]->prev(), op); | |
73 } | |
74 | |
75 | |
76 void VMOperationQueue::unlink(VM_Operation* q) { | |
77 assert(q->next()->prev() == q && q->prev()->next() == q, "sanity check"); | |
78 q->prev()->set_next(q->next()); | |
79 q->next()->set_prev(q->prev()); | |
80 } | |
81 | |
82 VM_Operation* VMOperationQueue::queue_remove_front(int prio) { | |
83 if (queue_empty(prio)) return NULL; | |
84 assert(_queue_length[prio] >= 0, "sanity check"); | |
85 _queue_length[prio]--; | |
86 VM_Operation* r = _queue[prio]->next(); | |
87 assert(r != _queue[prio], "cannot remove base element"); | |
88 unlink(r); | |
89 return r; | |
90 } | |
91 | |
92 VM_Operation* VMOperationQueue::queue_drain(int prio) { | |
93 if (queue_empty(prio)) return NULL; | |
94 DEBUG_ONLY(int length = _queue_length[prio];); | |
95 assert(length >= 0, "sanity check"); | |
96 _queue_length[prio] = 0; | |
97 VM_Operation* r = _queue[prio]->next(); | |
98 assert(r != _queue[prio], "cannot remove base element"); | |
99 // remove links to base element from head and tail | |
100 r->set_prev(NULL); | |
101 _queue[prio]->prev()->set_next(NULL); | |
102 // restore queue to empty state | |
103 _queue[prio]->set_next(_queue[prio]); | |
104 _queue[prio]->set_prev(_queue[prio]); | |
105 assert(queue_empty(prio), "drain corrupted queue") | |
106 #ifdef DEBUG | |
107 int len = 0; | |
108 VM_Operation* cur; | |
109 for(cur = r; cur != NULL; cur=cur->next()) len++; | |
110 assert(len == length, "drain lost some ops"); | |
111 #endif | |
112 return r; | |
113 } | |
114 | |
115 void VMOperationQueue::queue_oops_do(int queue, OopClosure* f) { | |
116 VM_Operation* cur = _queue[queue]; | |
117 cur = cur->next(); | |
118 while (cur != _queue[queue]) { | |
119 cur->oops_do(f); | |
120 cur = cur->next(); | |
121 } | |
122 } | |
123 | |
124 void VMOperationQueue::drain_list_oops_do(OopClosure* f) { | |
125 VM_Operation* cur = _drain_list; | |
126 while (cur != NULL) { | |
127 cur->oops_do(f); | |
128 cur = cur->next(); | |
129 } | |
130 } | |
131 | |
132 //----------------------------------------------------------------- | |
133 // High-level interface | |
134 bool VMOperationQueue::add(VM_Operation *op) { | |
135 // Encapsulates VM queue policy. Currently, that | |
136 // only involves putting them on the right list | |
137 if (op->evaluate_at_safepoint()) { | |
138 queue_add_back(SafepointPriority, op); | |
139 return true; | |
140 } | |
141 | |
142 queue_add_back(MediumPriority, op); | |
143 return true; | |
144 } | |
145 | |
146 VM_Operation* VMOperationQueue::remove_next() { | |
147 // Assuming VMOperation queue is two-level priority queue. If there are | |
148 // more than two priorities, we need a different scheduling algorithm. | |
149 assert(SafepointPriority == 0 && MediumPriority == 1 && nof_priorities == 2, | |
150 "current algorithm does not work"); | |
151 | |
152 // simple counter based scheduling to prevent starvation of lower priority | |
153 // queue. -- see 4390175 | |
154 int high_prio, low_prio; | |
155 if (_queue_counter++ < 10) { | |
156 high_prio = SafepointPriority; | |
157 low_prio = MediumPriority; | |
158 } else { | |
159 _queue_counter = 0; | |
160 high_prio = MediumPriority; | |
161 low_prio = SafepointPriority; | |
162 } | |
163 | |
164 return queue_remove_front(queue_empty(high_prio) ? low_prio : high_prio); | |
165 } | |
166 | |
167 void VMOperationQueue::oops_do(OopClosure* f) { | |
168 for(int i = 0; i < nof_priorities; i++) { | |
169 queue_oops_do(i, f); | |
170 } | |
171 drain_list_oops_do(f); | |
172 } | |
173 | |
174 | |
175 //------------------------------------------------------------------------------------------------------------------ | |
176 // Implementation of VMThread stuff | |
177 | |
178 bool VMThread::_should_terminate = false; | |
179 bool VMThread::_terminated = false; | |
180 Monitor* VMThread::_terminate_lock = NULL; | |
181 VMThread* VMThread::_vm_thread = NULL; | |
182 VM_Operation* VMThread::_cur_vm_operation = NULL; | |
183 VMOperationQueue* VMThread::_vm_queue = NULL; | |
184 PerfCounter* VMThread::_perf_accumulated_vm_operation_time = NULL; | |
185 | |
186 | |
187 void VMThread::create() { | |
188 assert(vm_thread() == NULL, "we can only allocate one VMThread"); | |
189 _vm_thread = new VMThread(); | |
190 | |
191 // Create VM operation queue | |
192 _vm_queue = new VMOperationQueue(); | |
193 guarantee(_vm_queue != NULL, "just checking"); | |
194 | |
195 _terminate_lock = new Monitor(Mutex::safepoint, "VMThread::_terminate_lock", true); | |
196 | |
197 if (UsePerfData) { | |
198 // jvmstat performance counters | |
199 Thread* THREAD = Thread::current(); | |
200 _perf_accumulated_vm_operation_time = | |
201 PerfDataManager::create_counter(SUN_THREADS, "vmOperationTime", | |
202 PerfData::U_Ticks, CHECK); | |
203 } | |
204 } | |
205 | |
206 | |
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207 VMThread::VMThread() : NamedThread() { |
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208 set_name("VM Thread"); |
0 | 209 } |
210 | |
211 void VMThread::destroy() { | |
212 if (_vm_thread != NULL) { | |
213 delete _vm_thread; | |
214 _vm_thread = NULL; // VM thread is gone | |
215 } | |
216 } | |
217 | |
218 void VMThread::run() { | |
219 assert(this == vm_thread(), "check"); | |
220 | |
221 this->initialize_thread_local_storage(); | |
222 this->record_stack_base_and_size(); | |
223 // Notify_lock wait checks on active_handles() to rewait in | |
224 // case of spurious wakeup, it should wait on the last | |
225 // value set prior to the notify | |
226 this->set_active_handles(JNIHandleBlock::allocate_block()); | |
227 | |
228 { | |
229 MutexLocker ml(Notify_lock); | |
230 Notify_lock->notify(); | |
231 } | |
232 // Notify_lock is destroyed by Threads::create_vm() | |
233 | |
234 int prio = (VMThreadPriority == -1) | |
235 ? os::java_to_os_priority[NearMaxPriority] | |
236 : VMThreadPriority; | |
237 // Note that I cannot call os::set_priority because it expects Java | |
238 // priorities and I am *explicitly* using OS priorities so that it's | |
239 // possible to set the VM thread priority higher than any Java thread. | |
240 os::set_native_priority( this, prio ); | |
241 | |
242 // Wait for VM_Operations until termination | |
243 this->loop(); | |
244 | |
245 // Note the intention to exit before safepointing. | |
246 // 6295565 This has the effect of waiting for any large tty | |
247 // outputs to finish. | |
248 if (xtty != NULL) { | |
249 ttyLocker ttyl; | |
250 xtty->begin_elem("destroy_vm"); | |
251 xtty->stamp(); | |
252 xtty->end_elem(); | |
253 assert(should_terminate(), "termination flag must be set"); | |
254 } | |
255 | |
256 // 4526887 let VM thread exit at Safepoint | |
257 SafepointSynchronize::begin(); | |
258 | |
259 if (VerifyBeforeExit) { | |
260 HandleMark hm(VMThread::vm_thread()); | |
261 // Among other things, this ensures that Eden top is correct. | |
262 Universe::heap()->prepare_for_verify(); | |
263 os::check_heap(); | |
264 Universe::verify(true, true); // Silent verification to not polute normal output | |
265 } | |
266 | |
267 CompileBroker::set_should_block(); | |
268 | |
269 // wait for threads (compiler threads or daemon threads) in the | |
270 // _thread_in_native state to block. | |
271 VM_Exit::wait_for_threads_in_native_to_block(); | |
272 | |
273 // signal other threads that VM process is gone | |
274 { | |
275 // Note: we must have the _no_safepoint_check_flag. Mutex::lock() allows | |
276 // VM thread to enter any lock at Safepoint as long as its _owner is NULL. | |
277 // If that happens after _terminate_lock->wait() has unset _owner | |
278 // but before it actually drops the lock and waits, the notification below | |
279 // may get lost and we will have a hang. To avoid this, we need to use | |
280 // Mutex::lock_without_safepoint_check(). | |
281 MutexLockerEx ml(_terminate_lock, Mutex::_no_safepoint_check_flag); | |
282 _terminated = true; | |
283 _terminate_lock->notify(); | |
284 } | |
285 | |
286 // Deletion must be done synchronously by the JNI DestroyJavaVM thread | |
287 // so that the VMThread deletion completes before the main thread frees | |
288 // up the CodeHeap. | |
289 | |
290 } | |
291 | |
292 | |
293 // Notify the VMThread that the last non-daemon JavaThread has terminated, | |
294 // and wait until operation is performed. | |
295 void VMThread::wait_for_vm_thread_exit() { | |
296 { MutexLocker mu(VMOperationQueue_lock); | |
297 _should_terminate = true; | |
298 VMOperationQueue_lock->notify(); | |
299 } | |
300 | |
301 // Note: VM thread leaves at Safepoint. We are not stopped by Safepoint | |
302 // because this thread has been removed from the threads list. But anything | |
303 // that could get blocked by Safepoint should not be used after this point, | |
304 // otherwise we will hang, since there is no one can end the safepoint. | |
305 | |
306 // Wait until VM thread is terminated | |
307 // Note: it should be OK to use Terminator_lock here. But this is called | |
308 // at a very delicate time (VM shutdown) and we are operating in non- VM | |
309 // thread at Safepoint. It's safer to not share lock with other threads. | |
310 { MutexLockerEx ml(_terminate_lock, Mutex::_no_safepoint_check_flag); | |
311 while(!VMThread::is_terminated()) { | |
312 _terminate_lock->wait(Mutex::_no_safepoint_check_flag); | |
313 } | |
314 } | |
315 } | |
316 | |
317 void VMThread::print_on(outputStream* st) const { | |
318 st->print("\"%s\" ", name()); | |
319 Thread::print_on(st); | |
320 st->cr(); | |
321 } | |
322 | |
323 void VMThread::evaluate_operation(VM_Operation* op) { | |
324 ResourceMark rm; | |
325 | |
326 { | |
327 PerfTraceTime vm_op_timer(perf_accumulated_vm_operation_time()); | |
328 op->evaluate(); | |
329 } | |
330 | |
331 // Last access of info in _cur_vm_operation! | |
332 bool c_heap_allocated = op->is_cheap_allocated(); | |
333 | |
334 // Mark as completed | |
335 if (!op->evaluate_concurrently()) { | |
336 op->calling_thread()->increment_vm_operation_completed_count(); | |
337 } | |
338 // It is unsafe to access the _cur_vm_operation after the 'increment_vm_operation_completed_count' call, | |
339 // since if it is stack allocated the calling thread might have deallocated | |
340 if (c_heap_allocated) { | |
341 delete _cur_vm_operation; | |
342 } | |
343 } | |
344 | |
345 | |
346 void VMThread::loop() { | |
347 assert(_cur_vm_operation == NULL, "no current one should be executing"); | |
348 | |
349 while(true) { | |
350 VM_Operation* safepoint_ops = NULL; | |
351 // | |
352 // Wait for VM operation | |
353 // | |
354 // use no_safepoint_check to get lock without attempting to "sneak" | |
355 { MutexLockerEx mu_queue(VMOperationQueue_lock, | |
356 Mutex::_no_safepoint_check_flag); | |
357 | |
358 // Look for new operation | |
359 assert(_cur_vm_operation == NULL, "no current one should be executing"); | |
360 _cur_vm_operation = _vm_queue->remove_next(); | |
361 | |
362 // Stall time tracking code | |
363 if (PrintVMQWaitTime && _cur_vm_operation != NULL && | |
364 !_cur_vm_operation->evaluate_concurrently()) { | |
365 long stall = os::javaTimeMillis() - _cur_vm_operation->timestamp(); | |
366 if (stall > 0) | |
367 tty->print_cr("%s stall: %Ld", _cur_vm_operation->name(), stall); | |
368 } | |
369 | |
370 while (!should_terminate() && _cur_vm_operation == NULL) { | |
371 // wait with a timeout to guarantee safepoints at regular intervals | |
372 bool timedout = | |
373 VMOperationQueue_lock->wait(Mutex::_no_safepoint_check_flag, | |
374 GuaranteedSafepointInterval); | |
375 | |
376 // Support for self destruction | |
377 if ((SelfDestructTimer != 0) && !is_error_reported() && | |
378 (os::elapsedTime() > SelfDestructTimer * 60)) { | |
379 tty->print_cr("VM self-destructed"); | |
380 exit(-1); | |
381 } | |
382 | |
383 if (timedout && (SafepointALot || | |
384 SafepointSynchronize::is_cleanup_needed())) { | |
385 MutexUnlockerEx mul(VMOperationQueue_lock, | |
386 Mutex::_no_safepoint_check_flag); | |
387 // Force a safepoint since we have not had one for at least | |
388 // 'GuaranteedSafepointInterval' milliseconds. This will run all | |
389 // the clean-up processing that needs to be done regularly at a | |
390 // safepoint | |
391 SafepointSynchronize::begin(); | |
392 #ifdef ASSERT | |
393 if (GCALotAtAllSafepoints) InterfaceSupport::check_gc_alot(); | |
394 #endif | |
395 SafepointSynchronize::end(); | |
396 } | |
397 _cur_vm_operation = _vm_queue->remove_next(); | |
398 | |
399 // If we are at a safepoint we will evaluate all the operations that | |
400 // follow that also require a safepoint | |
401 if (_cur_vm_operation != NULL && | |
402 _cur_vm_operation->evaluate_at_safepoint()) { | |
403 safepoint_ops = _vm_queue->drain_at_safepoint_priority(); | |
404 } | |
405 } | |
406 | |
407 if (should_terminate()) break; | |
408 } // Release mu_queue_lock | |
409 | |
410 // | |
411 // Execute VM operation | |
412 // | |
413 { HandleMark hm(VMThread::vm_thread()); | |
414 | |
415 EventMark em("Executing VM operation: %s", vm_operation()->name()); | |
416 assert(_cur_vm_operation != NULL, "we should have found an operation to execute"); | |
417 | |
418 // Give the VM thread an extra quantum. Jobs tend to be bursty and this | |
419 // helps the VM thread to finish up the job. | |
420 // FIXME: When this is enabled and there are many threads, this can degrade | |
421 // performance significantly. | |
422 if( VMThreadHintNoPreempt ) | |
423 os::hint_no_preempt(); | |
424 | |
425 // If we are at a safepoint we will evaluate all the operations that | |
426 // follow that also require a safepoint | |
427 if (_cur_vm_operation->evaluate_at_safepoint()) { | |
428 | |
429 if (PrintGCApplicationConcurrentTime) { | |
430 gclog_or_tty->print_cr("Application time: %3.7f seconds", | |
431 RuntimeService::last_application_time_sec()); | |
432 } | |
433 | |
434 _vm_queue->set_drain_list(safepoint_ops); // ensure ops can be scanned | |
435 | |
436 SafepointSynchronize::begin(); | |
437 evaluate_operation(_cur_vm_operation); | |
438 // now process all queued safepoint ops, iteratively draining | |
439 // the queue until there are none left | |
440 do { | |
441 _cur_vm_operation = safepoint_ops; | |
442 if (_cur_vm_operation != NULL) { | |
443 do { | |
444 // evaluate_operation deletes the op object so we have | |
445 // to grab the next op now | |
446 VM_Operation* next = _cur_vm_operation->next(); | |
447 _vm_queue->set_drain_list(next); | |
448 evaluate_operation(_cur_vm_operation); | |
449 _cur_vm_operation = next; | |
450 if (PrintSafepointStatistics) { | |
451 SafepointSynchronize::inc_vmop_coalesced_count(); | |
452 } | |
453 } while (_cur_vm_operation != NULL); | |
454 } | |
455 // There is a chance that a thread enqueued a safepoint op | |
456 // since we released the op-queue lock and initiated the safepoint. | |
457 // So we drain the queue again if there is anything there, as an | |
458 // optimization to try and reduce the number of safepoints. | |
459 // As the safepoint synchronizes us with JavaThreads we will see | |
460 // any enqueue made by a JavaThread, but the peek will not | |
461 // necessarily detect a concurrent enqueue by a GC thread, but | |
462 // that simply means the op will wait for the next major cycle of the | |
463 // VMThread - just as it would if the GC thread lost the race for | |
464 // the lock. | |
465 if (_vm_queue->peek_at_safepoint_priority()) { | |
466 // must hold lock while draining queue | |
467 MutexLockerEx mu_queue(VMOperationQueue_lock, | |
468 Mutex::_no_safepoint_check_flag); | |
469 safepoint_ops = _vm_queue->drain_at_safepoint_priority(); | |
470 } else { | |
471 safepoint_ops = NULL; | |
472 } | |
473 } while(safepoint_ops != NULL); | |
474 | |
475 _vm_queue->set_drain_list(NULL); | |
476 | |
477 // Complete safepoint synchronization | |
478 SafepointSynchronize::end(); | |
479 | |
480 if (PrintGCApplicationStoppedTime) { | |
481 gclog_or_tty->print_cr("Total time for which application threads " | |
482 "were stopped: %3.7f seconds", | |
483 RuntimeService::last_safepoint_time_sec()); | |
484 } | |
485 | |
486 } else { // not a safepoint operation | |
487 if (TraceLongCompiles) { | |
488 elapsedTimer t; | |
489 t.start(); | |
490 evaluate_operation(_cur_vm_operation); | |
491 t.stop(); | |
492 double secs = t.seconds(); | |
493 if (secs * 1e3 > LongCompileThreshold) { | |
494 // XXX - _cur_vm_operation should not be accessed after | |
495 // the completed count has been incremented; the waiting | |
496 // thread may have already freed this memory. | |
497 tty->print_cr("vm %s: %3.7f secs]", _cur_vm_operation->name(), secs); | |
498 } | |
499 } else { | |
500 evaluate_operation(_cur_vm_operation); | |
501 } | |
502 | |
503 _cur_vm_operation = NULL; | |
504 } | |
505 } | |
506 | |
507 // | |
508 // Notify (potential) waiting Java thread(s) - lock without safepoint | |
509 // check so that sneaking is not possible | |
510 { MutexLockerEx mu(VMOperationRequest_lock, | |
511 Mutex::_no_safepoint_check_flag); | |
512 VMOperationRequest_lock->notify_all(); | |
513 } | |
514 | |
515 // | |
516 // We want to make sure that we get to a safepoint regularly. | |
517 // | |
518 if (SafepointALot || SafepointSynchronize::is_cleanup_needed()) { | |
519 long interval = SafepointSynchronize::last_non_safepoint_interval(); | |
520 bool max_time_exceeded = GuaranteedSafepointInterval != 0 && (interval > GuaranteedSafepointInterval); | |
521 if (SafepointALot || max_time_exceeded) { | |
522 HandleMark hm(VMThread::vm_thread()); | |
523 SafepointSynchronize::begin(); | |
524 SafepointSynchronize::end(); | |
525 } | |
526 } | |
527 } | |
528 } | |
529 | |
530 void VMThread::execute(VM_Operation* op) { | |
531 Thread* t = Thread::current(); | |
532 | |
533 if (!t->is_VM_thread()) { | |
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534 SkipGCALot sgcalot(t); // avoid re-entrant attempts to gc-a-lot |
0 | 535 // JavaThread or WatcherThread |
536 t->check_for_valid_safepoint_state(true); | |
537 | |
538 // New request from Java thread, evaluate prologue | |
539 if (!op->doit_prologue()) { | |
540 return; // op was cancelled | |
541 } | |
542 | |
543 // Setup VM_operations for execution | |
544 op->set_calling_thread(t, Thread::get_priority(t)); | |
545 | |
546 // It does not make sense to execute the epilogue, if the VM operation object is getting | |
547 // deallocated by the VM thread. | |
548 bool concurrent = op->evaluate_concurrently(); | |
549 bool execute_epilog = !op->is_cheap_allocated(); | |
550 assert(!concurrent || op->is_cheap_allocated(), "concurrent => cheap_allocated"); | |
551 | |
552 // Get ticket number for non-concurrent VM operations | |
553 int ticket = 0; | |
554 if (!concurrent) { | |
555 ticket = t->vm_operation_ticket(); | |
556 } | |
557 | |
558 // Add VM operation to list of waiting threads. We are guaranteed not to block while holding the | |
559 // VMOperationQueue_lock, so we can block without a safepoint check. This allows vm operation requests | |
560 // to be queued up during a safepoint synchronization. | |
561 { | |
562 VMOperationQueue_lock->lock_without_safepoint_check(); | |
563 bool ok = _vm_queue->add(op); | |
564 op->set_timestamp(os::javaTimeMillis()); | |
565 VMOperationQueue_lock->notify(); | |
566 VMOperationQueue_lock->unlock(); | |
567 // VM_Operation got skipped | |
568 if (!ok) { | |
569 assert(concurrent, "can only skip concurrent tasks"); | |
570 if (op->is_cheap_allocated()) delete op; | |
571 return; | |
572 } | |
573 } | |
574 | |
575 if (!concurrent) { | |
576 // Wait for completion of request (non-concurrent) | |
577 // Note: only a JavaThread triggers the safepoint check when locking | |
578 MutexLocker mu(VMOperationRequest_lock); | |
579 while(t->vm_operation_completed_count() < ticket) { | |
580 VMOperationRequest_lock->wait(!t->is_Java_thread()); | |
581 } | |
582 } | |
583 | |
584 if (execute_epilog) { | |
585 op->doit_epilogue(); | |
586 } | |
587 } else { | |
588 // invoked by VM thread; usually nested VM operation | |
589 assert(t->is_VM_thread(), "must be a VM thread"); | |
590 VM_Operation* prev_vm_operation = vm_operation(); | |
591 if (prev_vm_operation != NULL) { | |
592 // Check the VM operation allows nested VM operation. This normally not the case, e.g., the compiler | |
593 // does not allow nested scavenges or compiles. | |
594 if (!prev_vm_operation->allow_nested_vm_operations()) { | |
595 fatal2("Nested VM operation %s requested by operation %s", op->name(), vm_operation()->name()); | |
596 } | |
597 op->set_calling_thread(prev_vm_operation->calling_thread(), prev_vm_operation->priority()); | |
598 } | |
599 | |
600 EventMark em("Executing %s VM operation: %s", prev_vm_operation ? "nested" : "", op->name()); | |
601 | |
602 // Release all internal handles after operation is evaluated | |
603 HandleMark hm(t); | |
604 _cur_vm_operation = op; | |
605 | |
606 if (op->evaluate_at_safepoint() && !SafepointSynchronize::is_at_safepoint()) { | |
607 SafepointSynchronize::begin(); | |
608 op->evaluate(); | |
609 SafepointSynchronize::end(); | |
610 } else { | |
611 op->evaluate(); | |
612 } | |
613 | |
614 // Free memory if needed | |
615 if (op->is_cheap_allocated()) delete op; | |
616 | |
617 _cur_vm_operation = prev_vm_operation; | |
618 } | |
619 } | |
620 | |
621 | |
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622 void VMThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { |
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623 Thread::oops_do(f, cf); |
0 | 624 _vm_queue->oops_do(f); |
625 } | |
626 | |
627 //------------------------------------------------------------------------------------------------------------------ | |
628 #ifndef PRODUCT | |
629 | |
630 void VMOperationQueue::verify_queue(int prio) { | |
631 // Check that list is correctly linked | |
632 int length = _queue_length[prio]; | |
633 VM_Operation *cur = _queue[prio]; | |
634 int i; | |
635 | |
636 // Check forward links | |
637 for(i = 0; i < length; i++) { | |
638 cur = cur->next(); | |
639 assert(cur != _queue[prio], "list to short (forward)"); | |
640 } | |
641 assert(cur->next() == _queue[prio], "list to long (forward)"); | |
642 | |
643 // Check backwards links | |
644 cur = _queue[prio]; | |
645 for(i = 0; i < length; i++) { | |
646 cur = cur->prev(); | |
647 assert(cur != _queue[prio], "list to short (backwards)"); | |
648 } | |
649 assert(cur->prev() == _queue[prio], "list to long (backwards)"); | |
650 } | |
651 | |
652 #endif | |
653 | |
654 void VMThread::verify() { | |
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655 oops_do(&VerifyOopClosure::verify_oop, NULL); |
0 | 656 } |