1 /*
2 * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoaderDataGraph.inline.hpp"
27 #include "classfile/dictionary.hpp"
28 #include "classfile/stringTable.hpp"
29 #include "classfile/symbolTable.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "code/codeCache.hpp"
32 #include "code/icBuffer.hpp"
33 #include "code/nmethod.hpp"
34 #include "code/pcDesc.hpp"
35 #include "code/scopeDesc.hpp"
36 #include "compiler/compilationPolicy.hpp"
37 #include "gc/shared/collectedHeap.hpp"
38 #include "gc/shared/gcLocker.hpp"
39 #include "gc/shared/oopStorage.hpp"
40 #include "gc/shared/strongRootsScope.hpp"
41 #include "gc/shared/workgroup.hpp"
42 #include "interpreter/interpreter.hpp"
43 #include "jfr/jfrEvents.hpp"
44 #include "logging/log.hpp"
45 #include "logging/logStream.hpp"
46 #include "memory/resourceArea.hpp"
47 #include "memory/universe.hpp"
48 #include "oops/oop.inline.hpp"
49 #include "oops/symbol.hpp"
50 #include "runtime/atomic.hpp"
51 #include "runtime/deoptimization.hpp"
52 #include "runtime/frame.inline.hpp"
53 #include "runtime/handles.inline.hpp"
54 #include "runtime/interfaceSupport.inline.hpp"
55 #include "runtime/mutexLocker.hpp"
56 #include "runtime/orderAccess.hpp"
57 #include "runtime/osThread.hpp"
58 #include "runtime/safepoint.hpp"
59 #include "runtime/safepointMechanism.inline.hpp"
60 #include "runtime/signature.hpp"
61 #include "runtime/stubCodeGenerator.hpp"
62 #include "runtime/stubRoutines.hpp"
63 #include "runtime/sweeper.hpp"
64 #include "runtime/synchronizer.hpp"
65 #include "runtime/thread.inline.hpp"
66 #include "runtime/threadSMR.hpp"
67 #include "runtime/timerTrace.hpp"
68 #include "services/runtimeService.hpp"
69 #include "utilities/events.hpp"
70 #include "utilities/macros.hpp"
71
72 static void post_safepoint_begin_event(EventSafepointBegin& event,
73 uint64_t safepoint_id,
74 int thread_count,
75 int critical_thread_count) {
76 if (event.should_commit()) {
77 event.set_safepointId(safepoint_id);
78 event.set_totalThreadCount(thread_count);
79 event.set_jniCriticalThreadCount(critical_thread_count);
80 event.commit();
81 }
82 }
83
84 static void post_safepoint_cleanup_event(EventSafepointCleanup& event, uint64_t safepoint_id) {
85 if (event.should_commit()) {
86 event.set_safepointId(safepoint_id);
87 event.commit();
88 }
89 }
90
91 static void post_safepoint_synchronize_event(EventSafepointStateSynchronization& event,
92 uint64_t safepoint_id,
93 int initial_number_of_threads,
94 int threads_waiting_to_block,
95 uint64_t iterations) {
96 if (event.should_commit()) {
97 event.set_safepointId(safepoint_id);
98 event.set_initialThreadCount(initial_number_of_threads);
99 event.set_runningThreadCount(threads_waiting_to_block);
100 event.set_iterations(iterations);
101 event.commit();
102 }
103 }
104
105 static void post_safepoint_cleanup_task_event(EventSafepointCleanupTask& event,
106 uint64_t safepoint_id,
107 const char* name) {
108 if (event.should_commit()) {
109 event.set_safepointId(safepoint_id);
110 event.set_name(name);
111 event.commit();
112 }
113 }
114
115 static void post_safepoint_end_event(EventSafepointEnd& event, uint64_t safepoint_id) {
116 if (event.should_commit()) {
117 event.set_safepointId(safepoint_id);
118 event.commit();
119 }
120 }
121
122 // SafepointCheck
123 SafepointStateTracker::SafepointStateTracker(uint64_t safepoint_id, bool at_safepoint)
124 : _safepoint_id(safepoint_id), _at_safepoint(at_safepoint) {}
125
126 bool SafepointStateTracker::safepoint_state_changed() {
127 return _safepoint_id != SafepointSynchronize::safepoint_id() ||
128 _at_safepoint != SafepointSynchronize::is_at_safepoint();
129 }
130
131 // --------------------------------------------------------------------------------------------------
132 // Implementation of Safepoint begin/end
133
134 SafepointSynchronize::SynchronizeState volatile SafepointSynchronize::_state = SafepointSynchronize::_not_synchronized;
135 int SafepointSynchronize::_waiting_to_block = 0;
136 volatile uint64_t SafepointSynchronize::_safepoint_counter = 0;
137 uint64_t SafepointSynchronize::_safepoint_id = 0;
138 const uint64_t SafepointSynchronize::InactiveSafepointCounter = 0;
139 int SafepointSynchronize::_current_jni_active_count = 0;
140
141 WaitBarrier* SafepointSynchronize::_wait_barrier;
142
143 static bool timeout_error_printed = false;
144
145 // Statistic related
146 static jlong _safepoint_begin_time = 0;
147 static volatile int _nof_threads_hit_polling_page = 0;
148
149 void SafepointSynchronize::init(Thread* vmthread) {
150 // WaitBarrier should never be destroyed since we will have
151 // threads waiting on it while exiting.
152 _wait_barrier = new WaitBarrier(vmthread);
153 SafepointTracing::init();
154 }
155
156 void SafepointSynchronize::increment_jni_active_count() {
157 assert(Thread::current()->is_VM_thread(), "Only VM thread may increment");
158 ++_current_jni_active_count;
159 }
160
161 void SafepointSynchronize::decrement_waiting_to_block() {
162 assert(_waiting_to_block > 0, "sanity check");
163 assert(Thread::current()->is_VM_thread(), "Only VM thread may decrement");
164 --_waiting_to_block;
165 }
166
167 bool SafepointSynchronize::thread_not_running(ThreadSafepointState *cur_state) {
168 if (!cur_state->is_running()) {
169 return true;
170 }
171 cur_state->examine_state_of_thread(SafepointSynchronize::safepoint_counter());
172 if (!cur_state->is_running()) {
173 return true;
174 }
175 LogTarget(Trace, safepoint) lt;
176 if (lt.is_enabled()) {
177 ResourceMark rm;
178 LogStream ls(lt);
179 cur_state->print_on(&ls);
180 }
181 return false;
182 }
183
184 #ifdef ASSERT
185 static void assert_list_is_valid(const ThreadSafepointState* tss_head, int still_running) {
186 int a = 0;
187 const ThreadSafepointState *tmp_tss = tss_head;
188 while (tmp_tss != NULL) {
189 ++a;
190 assert(tmp_tss->is_running(), "Illegal initial state");
191 tmp_tss = tmp_tss->get_next();
192 }
193 assert(a == still_running, "Must be the same");
194 }
195 #endif // ASSERT
196
197 static void back_off(int64_t start_time) {
198 // We start with fine-grained nanosleeping until a millisecond has
199 // passed, at which point we resort to plain naked_short_sleep.
200 if (os::javaTimeNanos() - start_time < NANOSECS_PER_MILLISEC) {
201 os::naked_short_nanosleep(10 * (NANOUNITS / MICROUNITS));
202 } else {
203 os::naked_short_sleep(1);
204 }
205 }
206
207 int SafepointSynchronize::synchronize_threads(jlong safepoint_limit_time, int nof_threads, int* initial_running)
208 {
209 JavaThreadIteratorWithHandle jtiwh;
210
211 #ifdef ASSERT
212 for (; JavaThread *cur = jtiwh.next(); ) {
213 assert(cur->safepoint_state()->is_running(), "Illegal initial state");
214 }
215 jtiwh.rewind();
216 #endif // ASSERT
217
218 // Iterate through all threads until it has been determined how to stop them all at a safepoint.
219 int still_running = nof_threads;
220 ThreadSafepointState *tss_head = NULL;
221 ThreadSafepointState **p_prev = &tss_head;
222 for (; JavaThread *cur = jtiwh.next(); ) {
223 ThreadSafepointState *cur_tss = cur->safepoint_state();
224 assert(cur_tss->get_next() == NULL, "Must be NULL");
225 if (thread_not_running(cur_tss)) {
226 --still_running;
227 } else {
228 *p_prev = cur_tss;
229 p_prev = cur_tss->next_ptr();
230 }
231 }
232 *p_prev = NULL;
233
234 DEBUG_ONLY(assert_list_is_valid(tss_head, still_running);)
235
236 *initial_running = still_running;
237
238 // If there is no thread still running, we are already done.
239 if (still_running <= 0) {
240 assert(tss_head == NULL, "Must be empty");
241 return 1;
242 }
243
244 int iterations = 1; // The first iteration is above.
245 int64_t start_time = os::javaTimeNanos();
246
247 do {
248 // Check if this has taken too long:
249 if (SafepointTimeout && safepoint_limit_time < os::javaTimeNanos()) {
250 print_safepoint_timeout();
251 }
252
253 p_prev = &tss_head;
254 ThreadSafepointState *cur_tss = tss_head;
255 while (cur_tss != NULL) {
256 assert(cur_tss->is_running(), "Illegal initial state");
257 if (thread_not_running(cur_tss)) {
258 --still_running;
259 *p_prev = NULL;
260 ThreadSafepointState *tmp = cur_tss;
261 cur_tss = cur_tss->get_next();
262 tmp->set_next(NULL);
263 } else {
264 *p_prev = cur_tss;
265 p_prev = cur_tss->next_ptr();
266 cur_tss = cur_tss->get_next();
267 }
268 }
269
270 DEBUG_ONLY(assert_list_is_valid(tss_head, still_running);)
271
272 if (still_running > 0) {
273 back_off(start_time);
274 }
275
276 iterations++;
277 } while (still_running > 0);
278
279 assert(tss_head == NULL, "Must be empty");
280
281 return iterations;
282 }
283
284 void SafepointSynchronize::arm_safepoint() {
285 // Begin the process of bringing the system to a safepoint.
286 // Java threads can be in several different states and are
287 // stopped by different mechanisms:
288 //
289 // 1. Running interpreted
290 // When executing branching/returning byte codes interpreter
291 // checks if the poll is armed, if so blocks in SS::block().
292 // 2. Running in native code
293 // When returning from the native code, a Java thread must check
294 // the safepoint _state to see if we must block. If the
295 // VM thread sees a Java thread in native, it does
296 // not wait for this thread to block. The order of the memory
297 // writes and reads of both the safepoint state and the Java
298 // threads state is critical. In order to guarantee that the
299 // memory writes are serialized with respect to each other,
300 // the VM thread issues a memory barrier instruction.
301 // 3. Running compiled Code
302 // Compiled code reads the local polling page that
303 // is set to fault if we are trying to get to a safepoint.
304 // 4. Blocked
305 // A thread which is blocked will not be allowed to return from the
306 // block condition until the safepoint operation is complete.
307 // 5. In VM or Transitioning between states
308 // If a Java thread is currently running in the VM or transitioning
309 // between states, the safepointing code will poll the thread state
310 // until the thread blocks itself when it attempts transitions to a
311 // new state or locking a safepoint checked monitor.
312
313 // We must never miss a thread with correct safepoint id, so we must make sure we arm
314 // the wait barrier for the next safepoint id/counter.
315 // Arming must be done after resetting _current_jni_active_count, _waiting_to_block.
316 _wait_barrier->arm(static_cast<int>(_safepoint_counter + 1));
317
318 assert((_safepoint_counter & 0x1) == 0, "must be even");
319 // The store to _safepoint_counter must happen after any stores in arming.
320 Atomic::release_store(&_safepoint_counter, _safepoint_counter + 1);
321
322 // We are synchronizing
323 OrderAccess::storestore(); // Ordered with _safepoint_counter
324 _state = _synchronizing;
325
326 // Arming the per thread poll while having _state != _not_synchronized means safepointing
327 log_trace(safepoint)("Setting thread local yield flag for threads");
328 OrderAccess::storestore(); // storestore, global state -> local state
329 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *cur = jtiwh.next(); ) {
330 // Make sure the threads start polling, it is time to yield.
331 SafepointMechanism::arm_local_poll(cur);
332 }
333
334 OrderAccess::fence(); // storestore|storeload, global state -> local state
335 }
336
337 // Roll all threads forward to a safepoint and suspend them all
338 void SafepointSynchronize::begin() {
339 assert(Thread::current()->is_VM_thread(), "Only VM thread may execute a safepoint");
340
341 EventSafepointBegin begin_event;
342 SafepointTracing::begin(VMThread::vm_op_type());
343
344 Universe::heap()->safepoint_synchronize_begin();
345
346 // By getting the Threads_lock, we assure that no threads are about to start or
347 // exit. It is released again in SafepointSynchronize::end().
348 Threads_lock->lock();
349
350 assert( _state == _not_synchronized, "trying to safepoint synchronize with wrong state");
351
352 int nof_threads = Threads::number_of_threads();
353
354 _nof_threads_hit_polling_page = 0;
355
356 log_debug(safepoint)("Safepoint synchronization initiated using %s wait barrier. (%d threads)", _wait_barrier->description(), nof_threads);
357
358 // Reset the count of active JNI critical threads
359 _current_jni_active_count = 0;
360
361 // Set number of threads to wait for
362 _waiting_to_block = nof_threads;
363
364 jlong safepoint_limit_time = 0;
365 if (SafepointTimeout) {
366 // Set the limit time, so that it can be compared to see if this has taken
367 // too long to complete.
368 safepoint_limit_time = SafepointTracing::start_of_safepoint() + (jlong)SafepointTimeoutDelay * (NANOUNITS / MILLIUNITS);
369 timeout_error_printed = false;
370 }
371
372 EventSafepointStateSynchronization sync_event;
373 int initial_running = 0;
374
375 // Arms the safepoint, _current_jni_active_count and _waiting_to_block must be set before.
376 arm_safepoint();
377
378 // Will spin until all threads are safe.
379 int iterations = synchronize_threads(safepoint_limit_time, nof_threads, &initial_running);
380 assert(_waiting_to_block == 0, "No thread should be running");
381
382 #ifndef PRODUCT
383 if (safepoint_limit_time != 0) {
384 jlong current_time = os::javaTimeNanos();
385 if (safepoint_limit_time < current_time) {
386 log_warning(safepoint)("# SafepointSynchronize: Finished after "
387 INT64_FORMAT_W(6) " ms",
388 (int64_t)(current_time - SafepointTracing::start_of_safepoint()) / (NANOUNITS / MILLIUNITS));
389 }
390 }
391 #endif
392
393 assert(Threads_lock->owned_by_self(), "must hold Threads_lock");
394
395 // Record state
396 _state = _synchronized;
397
398 OrderAccess::fence();
399
400 // Set the new id
401 ++_safepoint_id;
402
403 #ifdef ASSERT
404 // Make sure all the threads were visited.
405 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *cur = jtiwh.next(); ) {
406 assert(cur->was_visited_for_critical_count(_safepoint_counter), "missed a thread");
407 }
408 #endif // ASSERT
409
410 // Update the count of active JNI critical regions
411 GCLocker::set_jni_lock_count(_current_jni_active_count);
412
413 post_safepoint_synchronize_event(sync_event,
414 _safepoint_id,
415 initial_running,
416 _waiting_to_block, iterations);
417
418 SafepointTracing::synchronized(nof_threads, initial_running, _nof_threads_hit_polling_page);
419
420 // We do the safepoint cleanup first since a GC related safepoint
421 // needs cleanup to be completed before running the GC op.
422 EventSafepointCleanup cleanup_event;
423 do_cleanup_tasks();
424 post_safepoint_cleanup_event(cleanup_event, _safepoint_id);
425
426 post_safepoint_begin_event(begin_event, _safepoint_id, nof_threads, _current_jni_active_count);
427 SafepointTracing::cleanup();
428 }
429
430 void SafepointSynchronize::disarm_safepoint() {
431 uint64_t active_safepoint_counter = _safepoint_counter;
432 {
433 JavaThreadIteratorWithHandle jtiwh;
434 #ifdef ASSERT
435 // A pending_exception cannot be installed during a safepoint. The threads
436 // may install an async exception after they come back from a safepoint into
437 // pending_exception after they unblock. But that should happen later.
438 for (; JavaThread *cur = jtiwh.next(); ) {
439 assert (!(cur->has_pending_exception() &&
440 cur->safepoint_state()->is_at_poll_safepoint()),
441 "safepoint installed a pending exception");
442 }
443 #endif // ASSERT
444
445 OrderAccess::fence(); // keep read and write of _state from floating up
446 assert(_state == _synchronized, "must be synchronized before ending safepoint synchronization");
447
448 // Change state first to _not_synchronized.
449 // No threads should see _synchronized when running.
450 _state = _not_synchronized;
451
452 // Set the next dormant (even) safepoint id.
453 assert((_safepoint_counter & 0x1) == 1, "must be odd");
454 Atomic::release_store(&_safepoint_counter, _safepoint_counter + 1);
455
456 OrderAccess::fence(); // Keep the local state from floating up.
457
458 jtiwh.rewind();
459 for (; JavaThread *current = jtiwh.next(); ) {
460 // Clear the visited flag to ensure that the critical counts are collected properly.
461 DEBUG_ONLY(current->reset_visited_for_critical_count(active_safepoint_counter);)
462 ThreadSafepointState* cur_state = current->safepoint_state();
463 assert(!cur_state->is_running(), "Thread not suspended at safepoint");
464 cur_state->restart(); // TSS _running
465 assert(cur_state->is_running(), "safepoint state has not been reset");
466 }
467 } // ~JavaThreadIteratorWithHandle
468
469 // Release threads lock, so threads can be created/destroyed again.
470 Threads_lock->unlock();
471
472 // Wake threads after local state is correctly set.
473 _wait_barrier->disarm();
474 }
475
476 // Wake up all threads, so they are ready to resume execution after the safepoint
477 // operation has been carried out
478 void SafepointSynchronize::end() {
479 assert(Threads_lock->owned_by_self(), "must hold Threads_lock");
480 EventSafepointEnd event;
481 assert(Thread::current()->is_VM_thread(), "Only VM thread can execute a safepoint");
482
483 disarm_safepoint();
484
485 Universe::heap()->safepoint_synchronize_end();
486
487 SafepointTracing::end();
488
489 post_safepoint_end_event(event, safepoint_id());
490 }
491
492 bool SafepointSynchronize::is_cleanup_needed() {
493 // Need a safepoint if some inline cache buffers is non-empty
494 if (!InlineCacheBuffer::is_empty()) return true;
495 if (StringTable::needs_rehashing()) return true;
496 if (SymbolTable::needs_rehashing()) return true;
497 return false;
498 }
499
500 class ParallelSPCleanupTask : public AbstractGangTask {
501 private:
502 SubTasksDone _subtasks;
503 uint _num_workers;
504 public:
505 ParallelSPCleanupTask(uint num_workers) :
506 AbstractGangTask("Parallel Safepoint Cleanup"),
507 _subtasks(SafepointSynchronize::SAFEPOINT_CLEANUP_NUM_TASKS),
508 _num_workers(num_workers) {}
509
510 void work(uint worker_id) {
511 uint64_t safepoint_id = SafepointSynchronize::safepoint_id();
512
513 if (_subtasks.try_claim_task(SafepointSynchronize::SAFEPOINT_CLEANUP_DEFLATE_MONITORS)) {
514 const char* name = "deflating idle monitors";
515 EventSafepointCleanupTask event;
516 TraceTime timer(name, TRACETIME_LOG(Info, safepoint, cleanup));
517 ObjectSynchronizer::do_safepoint_work();
518
519 post_safepoint_cleanup_task_event(event, safepoint_id, name);
520 }
521
522 if (_subtasks.try_claim_task(SafepointSynchronize::SAFEPOINT_CLEANUP_UPDATE_INLINE_CACHES)) {
523 const char* name = "updating inline caches";
524 EventSafepointCleanupTask event;
525 TraceTime timer(name, TRACETIME_LOG(Info, safepoint, cleanup));
526 InlineCacheBuffer::update_inline_caches();
527
528 post_safepoint_cleanup_task_event(event, safepoint_id, name);
529 }
530
531 if (_subtasks.try_claim_task(SafepointSynchronize::SAFEPOINT_CLEANUP_COMPILATION_POLICY)) {
532 const char* name = "compilation policy safepoint handler";
533 EventSafepointCleanupTask event;
534 TraceTime timer(name, TRACETIME_LOG(Info, safepoint, cleanup));
535 CompilationPolicy::policy()->do_safepoint_work();
536
537 post_safepoint_cleanup_task_event(event, safepoint_id, name);
538 }
539
540 if (_subtasks.try_claim_task(SafepointSynchronize::SAFEPOINT_CLEANUP_SYMBOL_TABLE_REHASH)) {
541 if (SymbolTable::needs_rehashing()) {
542 const char* name = "rehashing symbol table";
543 EventSafepointCleanupTask event;
544 TraceTime timer(name, TRACETIME_LOG(Info, safepoint, cleanup));
545 SymbolTable::rehash_table();
546
547 post_safepoint_cleanup_task_event(event, safepoint_id, name);
548 }
549 }
550
551 if (_subtasks.try_claim_task(SafepointSynchronize::SAFEPOINT_CLEANUP_STRING_TABLE_REHASH)) {
552 if (StringTable::needs_rehashing()) {
553 const char* name = "rehashing string table";
554 EventSafepointCleanupTask event;
555 TraceTime timer(name, TRACETIME_LOG(Info, safepoint, cleanup));
556 StringTable::rehash_table();
557
558 post_safepoint_cleanup_task_event(event, safepoint_id, name);
559 }
560 }
561
562 if (_subtasks.try_claim_task(SafepointSynchronize::SAFEPOINT_CLEANUP_SYSTEM_DICTIONARY_RESIZE)) {
563 if (Dictionary::does_any_dictionary_needs_resizing()) {
564 const char* name = "resizing system dictionaries";
565 EventSafepointCleanupTask event;
566 TraceTime timer(name, TRACETIME_LOG(Info, safepoint, cleanup));
567 ClassLoaderDataGraph::resize_dictionaries();
568
569 post_safepoint_cleanup_task_event(event, safepoint_id, name);
570 }
571 }
572
573 if (_subtasks.try_claim_task(SafepointSynchronize::SAFEPOINT_CLEANUP_REQUEST_OOPSTORAGE_CLEANUP)) {
574 // Don't bother reporting event or time for this very short operation.
575 // To have any utility we'd also want to report whether needed.
576 OopStorage::trigger_cleanup_if_needed();
577 }
578
579 _subtasks.all_tasks_completed(_num_workers);
580 }
581 };
582
583 // Various cleaning tasks that should be done periodically at safepoints.
584 void SafepointSynchronize::do_cleanup_tasks() {
585
586 TraceTime timer("safepoint cleanup tasks", TRACETIME_LOG(Info, safepoint, cleanup));
587
588 CollectedHeap* heap = Universe::heap();
589 assert(heap != NULL, "heap not initialized yet?");
590 WorkGang* cleanup_workers = heap->get_safepoint_workers();
591 if (cleanup_workers != NULL) {
592 // Parallel cleanup using GC provided thread pool.
593 uint num_cleanup_workers = cleanup_workers->active_workers();
594 ParallelSPCleanupTask cleanup(num_cleanup_workers);
595 cleanup_workers->run_task(&cleanup);
596 } else {
597 // Serial cleanup using VMThread.
598 ParallelSPCleanupTask cleanup(1);
599 cleanup.work(0);
600 }
601
602 // Needs to be done single threaded by the VMThread. This walks
603 // the thread stacks looking for references to metadata before
604 // deciding to remove it from the metaspaces.
605 if (ClassLoaderDataGraph::should_clean_metaspaces_and_reset()) {
606 const char* name = "cleanup live ClassLoaderData metaspaces";
607 TraceTime timer(name, TRACETIME_LOG(Info, safepoint, cleanup));
608 ClassLoaderDataGraph::walk_metadata_and_clean_metaspaces();
609 }
610
611 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
612 }
613
614 // Methods for determining if a JavaThread is safepoint safe.
615
616 // False means unsafe with undetermined state.
617 // True means a determined state, but it may be an unsafe state.
618 // If called from a non-safepoint context safepoint_count MUST be InactiveSafepointCounter.
619 bool SafepointSynchronize::try_stable_load_state(JavaThreadState *state, JavaThread *thread, uint64_t safepoint_count) {
620 assert((safepoint_count != InactiveSafepointCounter &&
621 Thread::current() == (Thread*)VMThread::vm_thread() &&
622 SafepointSynchronize::_state != _not_synchronized)
623 || safepoint_count == InactiveSafepointCounter, "Invalid check");
624
625 // To handle the thread_blocked state on the backedge of the WaitBarrier from
626 // previous safepoint and reading the reset value (0/InactiveSafepointCounter) we
627 // re-read state after we read thread safepoint id. The JavaThread changes its
628 // thread state from thread_blocked before resetting safepoint id to 0.
629 // This guarantees the second read will be from an updated thread state. It can
630 // either be different state making this an unsafe state or it can see blocked
631 // again. When we see blocked twice with a 0 safepoint id, either:
632 // - It is normally blocked, e.g. on Mutex, TBIVM.
633 // - It was in SS:block(), looped around to SS:block() and is blocked on the WaitBarrier.
634 // - It was in SS:block() but now on a Mutex.
635 // All of these cases are safe.
636
637 *state = thread->thread_state();
638 OrderAccess::loadload();
639 uint64_t sid = thread->safepoint_state()->get_safepoint_id(); // Load acquire
640 if (sid != InactiveSafepointCounter && sid != safepoint_count) {
641 // In an old safepoint, state not relevant.
642 return false;
643 }
644 return *state == thread->thread_state();
645 }
646
647 static bool safepoint_safe_with(JavaThread *thread, JavaThreadState state) {
648 switch(state) {
649 case _thread_in_native:
650 // native threads are safe if they have no java stack or have walkable stack
651 return !thread->has_last_Java_frame() || thread->frame_anchor()->walkable();
652
653 case _thread_blocked:
654 // On wait_barrier or blocked.
655 // Blocked threads should already have walkable stack.
656 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "blocked and not walkable");
657 return true;
658
659 default:
660 return false;
661 }
662 }
663
664 bool SafepointSynchronize::handshake_safe(JavaThread *thread) {
665 if (thread->is_ext_suspended() || thread->is_terminated()) {
666 return true;
667 }
668 JavaThreadState stable_state;
669 if (try_stable_load_state(&stable_state, thread, InactiveSafepointCounter)) {
670 return safepoint_safe_with(thread, stable_state);
671 }
672 return false;
673 }
674
675 // See if the thread is running inside a lazy critical native and
676 // update the thread critical count if so. Also set a suspend flag to
677 // cause the native wrapper to return into the JVM to do the unlock
678 // once the native finishes.
679 static void check_for_lazy_critical_native(JavaThread *thread, JavaThreadState state) {
680 if (state == _thread_in_native &&
681 thread->has_last_Java_frame() &&
682 thread->frame_anchor()->walkable()) {
683 // This thread might be in a critical native nmethod so look at
684 // the top of the stack and increment the critical count if it
685 // is.
686 frame wrapper_frame = thread->last_frame();
687 CodeBlob* stub_cb = wrapper_frame.cb();
688 if (stub_cb != NULL &&
689 stub_cb->is_nmethod() &&
690 stub_cb->as_nmethod_or_null()->is_lazy_critical_native()) {
691 // A thread could potentially be in a critical native across
692 // more than one safepoint, so only update the critical state on
693 // the first one. When it returns it will perform the unlock.
694 if (!thread->do_critical_native_unlock()) {
695 #ifdef ASSERT
696 if (!thread->in_critical()) {
697 GCLocker::increment_debug_jni_lock_count();
698 }
699 #endif
700 thread->enter_critical();
701 // Make sure the native wrapper calls back on return to
702 // perform the needed critical unlock.
703 thread->set_critical_native_unlock();
704 }
705 }
706 }
707 }
708
709 // -------------------------------------------------------------------------------------------------------
710 // Implementation of Safepoint blocking point
711
712 void SafepointSynchronize::block(JavaThread *thread) {
713 assert(thread != NULL, "thread must be set");
714 assert(thread->is_Java_thread(), "not a Java thread");
715
716 // Threads shouldn't block if they are in the middle of printing, but...
717 ttyLocker::break_tty_lock_for_safepoint(os::current_thread_id());
718
719 // Only bail from the block() call if the thread is gone from the
720 // thread list; starting to exit should still block.
721 if (thread->is_terminated()) {
722 // block current thread if we come here from native code when VM is gone
723 thread->block_if_vm_exited();
724
725 // otherwise do nothing
726 return;
727 }
728
729 JavaThreadState state = thread->thread_state();
730 thread->frame_anchor()->make_walkable(thread);
731
732 uint64_t safepoint_id = SafepointSynchronize::safepoint_counter();
733 // Check that we have a valid thread_state at this point
734 switch(state) {
735 case _thread_in_vm_trans:
736 case _thread_in_Java: // From compiled code
737 case _thread_in_native_trans:
738 case _thread_blocked_trans:
739 case _thread_new_trans:
740
741 // We have no idea where the VMThread is, it might even be at next safepoint.
742 // So we can miss this poll, but stop at next.
743
744 // Load dependent store, it must not pass loading of safepoint_id.
745 thread->safepoint_state()->set_safepoint_id(safepoint_id); // Release store
746
747 // This part we can skip if we notice we miss or are in a future safepoint.
748 OrderAccess::storestore();
749 // Load in wait barrier should not float up
750 thread->set_thread_state_fence(_thread_blocked);
751
752 _wait_barrier->wait(static_cast<int>(safepoint_id));
753 assert(_state != _synchronized, "Can't be");
754
755 // If barrier is disarmed stop store from floating above loads in barrier.
756 OrderAccess::loadstore();
757 thread->set_thread_state(state);
758
759 // Then we reset the safepoint id to inactive.
760 thread->safepoint_state()->reset_safepoint_id(); // Release store
761
762 OrderAccess::fence();
763
764 break;
765
766 default:
767 fatal("Illegal threadstate encountered: %d", state);
768 }
769 guarantee(thread->safepoint_state()->get_safepoint_id() == InactiveSafepointCounter,
770 "The safepoint id should be set only in block path");
771
772 // Check for pending. async. exceptions or suspends - except if the
773 // thread was blocked inside the VM. has_special_runtime_exit_condition()
774 // is called last since it grabs a lock and we only want to do that when
775 // we must.
776 //
777 // Note: we never deliver an async exception at a polling point as the
778 // compiler may not have an exception handler for it. The polling
779 // code will notice the async and deoptimize and the exception will
780 // be delivered. (Polling at a return point is ok though). Sure is
781 // a lot of bother for a deprecated feature...
782 //
783 // We don't deliver an async exception if the thread state is
784 // _thread_in_native_trans so JNI functions won't be called with
785 // a surprising pending exception. If the thread state is going back to java,
786 // async exception is checked in check_special_condition_for_native_trans().
787
788 if (state != _thread_blocked_trans &&
789 state != _thread_in_vm_trans &&
790 thread->has_special_runtime_exit_condition()) {
791 thread->handle_special_runtime_exit_condition(
792 !thread->is_at_poll_safepoint() && (state != _thread_in_native_trans));
793 }
794
795 // cross_modify_fence is done by SafepointMechanism::block_if_requested_slow
796 // which is the only caller here.
797 }
798
799 // ------------------------------------------------------------------------------------------------------
800 // Exception handlers
801
802
803 void SafepointSynchronize::handle_polling_page_exception(JavaThread *thread) {
804 assert(thread->is_Java_thread(), "polling reference encountered by VM thread");
805 assert(thread->thread_state() == _thread_in_Java, "should come from Java code");
806
807 if (log_is_enabled(Info, safepoint, stats)) {
808 Atomic::inc(&_nof_threads_hit_polling_page);
809 }
810
811 ThreadSafepointState* state = thread->safepoint_state();
812
813 state->handle_polling_page_exception();
814 }
815
816
817 void SafepointSynchronize::print_safepoint_timeout() {
818 if (!timeout_error_printed) {
819 timeout_error_printed = true;
820 // Print out the thread info which didn't reach the safepoint for debugging
821 // purposes (useful when there are lots of threads in the debugger).
822 LogTarget(Warning, safepoint) lt;
823 if (lt.is_enabled()) {
824 ResourceMark rm;
825 LogStream ls(lt);
826
827 ls.cr();
828 ls.print_cr("# SafepointSynchronize::begin: Timeout detected:");
829 ls.print_cr("# SafepointSynchronize::begin: Timed out while spinning to reach a safepoint.");
830 ls.print_cr("# SafepointSynchronize::begin: Threads which did not reach the safepoint:");
831 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *cur_thread = jtiwh.next(); ) {
832 if (cur_thread->safepoint_state()->is_running()) {
833 ls.print("# ");
834 cur_thread->print_on(&ls);
835 ls.cr();
836 }
837 }
838 ls.print_cr("# SafepointSynchronize::begin: (End of list)");
839 }
840 }
841
842 // To debug the long safepoint, specify both AbortVMOnSafepointTimeout &
843 // ShowMessageBoxOnError.
844 if (AbortVMOnSafepointTimeout) {
845 // Send the blocking thread a signal to terminate and write an error file.
846 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *cur_thread = jtiwh.next(); ) {
847 if (cur_thread->safepoint_state()->is_running()) {
848 if (!os::signal_thread(cur_thread, SIGILL, "blocking a safepoint")) {
849 break; // Could not send signal. Report fatal error.
850 }
851 // Give cur_thread a chance to report the error and terminate the VM.
852 os::naked_sleep(3000);
853 }
854 }
855 fatal("Safepoint sync time longer than " INTX_FORMAT "ms detected when executing %s.",
856 SafepointTimeoutDelay, VMThread::vm_operation()->name());
857 }
858 }
859
860 // -------------------------------------------------------------------------------------------------------
861 // Implementation of ThreadSafepointState
862
863 ThreadSafepointState::ThreadSafepointState(JavaThread *thread)
864 : _at_poll_safepoint(false), _thread(thread), _safepoint_safe(false),
865 _safepoint_id(SafepointSynchronize::InactiveSafepointCounter), _next(NULL) {
866 }
867
868 void ThreadSafepointState::create(JavaThread *thread) {
869 ThreadSafepointState *state = new ThreadSafepointState(thread);
870 thread->set_safepoint_state(state);
871 }
872
873 void ThreadSafepointState::destroy(JavaThread *thread) {
874 if (thread->safepoint_state()) {
875 delete(thread->safepoint_state());
876 thread->set_safepoint_state(NULL);
877 }
878 }
879
880 uint64_t ThreadSafepointState::get_safepoint_id() const {
881 return Atomic::load_acquire(&_safepoint_id);
882 }
883
884 void ThreadSafepointState::reset_safepoint_id() {
885 Atomic::release_store(&_safepoint_id, SafepointSynchronize::InactiveSafepointCounter);
886 }
887
888 void ThreadSafepointState::set_safepoint_id(uint64_t safepoint_id) {
889 Atomic::release_store(&_safepoint_id, safepoint_id);
890 }
891
892 void ThreadSafepointState::examine_state_of_thread(uint64_t safepoint_count) {
893 assert(is_running(), "better be running or just have hit safepoint poll");
894
895 JavaThreadState stable_state;
896 if (!SafepointSynchronize::try_stable_load_state(&stable_state, _thread, safepoint_count)) {
897 // We could not get stable state of the JavaThread.
898 // Consider it running and just return.
899 return;
900 }
901
902 // Check for a thread that is suspended. Note that thread resume tries
903 // to grab the Threads_lock which we own here, so a thread cannot be
904 // resumed during safepoint synchronization.
905
906 // We check to see if this thread is suspended without locking to
907 // avoid deadlocking with a third thread that is waiting for this
908 // thread to be suspended. The third thread can notice the safepoint
909 // that we're trying to start at the beginning of its SR_lock->wait()
910 // call. If that happens, then the third thread will block on the
911 // safepoint while still holding the underlying SR_lock. We won't be
912 // able to get the SR_lock and we'll deadlock.
913 //
914 // We don't need to grab the SR_lock here for two reasons:
915 // 1) The suspend flags are both volatile and are set with an
916 // Atomic::cmpxchg() call so we should see the suspended
917 // state right away.
918 // 2) We're being called from the safepoint polling loop; if
919 // we don't see the suspended state on this iteration, then
920 // we'll come around again.
921 //
922 bool is_suspended = _thread->is_ext_suspended();
923 if (is_suspended) {
924 account_safe_thread();
925 return;
926 }
927
928 if (safepoint_safe_with(_thread, stable_state)) {
929 check_for_lazy_critical_native(_thread, stable_state);
930 account_safe_thread();
931 return;
932 }
933
934 // All other thread states will continue to run until they
935 // transition and self-block in state _blocked
936 // Safepoint polling in compiled code causes the Java threads to do the same.
937 // Note: new threads may require a malloc so they must be allowed to finish
938
939 assert(is_running(), "examine_state_of_thread on non-running thread");
940 return;
941 }
942
943 void ThreadSafepointState::account_safe_thread() {
944 SafepointSynchronize::decrement_waiting_to_block();
945 if (_thread->in_critical()) {
946 // Notice that this thread is in a critical section
947 SafepointSynchronize::increment_jni_active_count();
948 }
949 DEBUG_ONLY(_thread->set_visited_for_critical_count(SafepointSynchronize::safepoint_counter());)
950 assert(!_safepoint_safe, "Must be unsafe before safe");
951 _safepoint_safe = true;
952 }
953
954 void ThreadSafepointState::restart() {
955 assert(_safepoint_safe, "Must be safe before unsafe");
956 _safepoint_safe = false;
957 }
958
959 void ThreadSafepointState::print_on(outputStream *st) const {
960 const char *s = _safepoint_safe ? "_at_safepoint" : "_running";
961
962 st->print_cr("Thread: " INTPTR_FORMAT
963 " [0x%2x] State: %s _at_poll_safepoint %d",
964 p2i(_thread), _thread->osthread()->thread_id(), s, _at_poll_safepoint);
965
966 _thread->print_thread_state_on(st);
967 }
968
969 // ---------------------------------------------------------------------------------------------------------------------
970
971 // Block the thread at poll or poll return for safepoint/handshake.
972 void ThreadSafepointState::handle_polling_page_exception() {
973
974 // Step 1: Find the nmethod from the return address
975 address real_return_addr = thread()->saved_exception_pc();
976
977 CodeBlob *cb = CodeCache::find_blob(real_return_addr);
978 assert(cb != NULL && cb->is_compiled(), "return address should be in nmethod");
979 CompiledMethod* nm = (CompiledMethod*)cb;
980
981 // Find frame of caller
982 frame stub_fr = thread()->last_frame();
983 CodeBlob* stub_cb = stub_fr.cb();
984 assert(stub_cb->is_safepoint_stub(), "must be a safepoint stub");
985 RegisterMap map(thread(), true);
986 frame caller_fr = stub_fr.sender(&map);
987
988 // Should only be poll_return or poll
989 assert( nm->is_at_poll_or_poll_return(real_return_addr), "should not be at call" );
990
991 // This is a poll immediately before a return. The exception handling code
992 // has already had the effect of causing the return to occur, so the execution
993 // will continue immediately after the call. In addition, the oopmap at the
994 // return point does not mark the return value as an oop (if it is), so
995 // it needs a handle here to be updated.
996 if( nm->is_at_poll_return(real_return_addr) ) {
997 // See if return type is an oop.
998 bool return_oop = nm->method()->is_returning_oop();
999 Handle return_value;
1000 if (return_oop) {
1001 // The oop result has been saved on the stack together with all
1002 // the other registers. In order to preserve it over GCs we need
1003 // to keep it in a handle.
1004 oop result = caller_fr.saved_oop_result(&map);
1005 assert(oopDesc::is_oop_or_null(result), "must be oop");
1006 return_value = Handle(thread(), result);
1007 assert(Universe::heap()->is_in_or_null(result), "must be heap pointer");
1008 }
1009
1010 // Block the thread
1011 SafepointMechanism::block_if_requested(thread());
1012
1013 // restore oop result, if any
1014 if (return_oop) {
1015 caller_fr.set_saved_oop_result(&map, return_value());
1016 }
1017 }
1018
1019 // This is a safepoint poll. Verify the return address and block.
1020 else {
1021 set_at_poll_safepoint(true);
1022
1023 // verify the blob built the "return address" correctly
1024 assert(real_return_addr == caller_fr.pc(), "must match");
1025
1026 // Block the thread
1027 SafepointMechanism::block_if_requested(thread());
1028 set_at_poll_safepoint(false);
1029
1030 // If we have a pending async exception deoptimize the frame
1031 // as otherwise we may never deliver it.
1032 if (thread()->has_async_condition()) {
1033 ThreadInVMfromJavaNoAsyncException __tiv(thread());
1034 Deoptimization::deoptimize_frame(thread(), caller_fr.id());
1035 }
1036
1037 // If an exception has been installed we must check for a pending deoptimization
1038 // Deoptimize frame if exception has been thrown.
1039
1040 if (thread()->has_pending_exception() ) {
1041 RegisterMap map(thread(), true);
1042 frame caller_fr = stub_fr.sender(&map);
1043 if (caller_fr.is_deoptimized_frame()) {
1044 // The exception patch will destroy registers that are still
1045 // live and will be needed during deoptimization. Defer the
1046 // Async exception should have deferred the exception until the
1047 // next safepoint which will be detected when we get into
1048 // the interpreter so if we have an exception now things
1049 // are messed up.
1050
1051 fatal("Exception installed and deoptimization is pending");
1052 }
1053 }
1054 }
1055 }
1056
1057
1058 // -------------------------------------------------------------------------------------------------------
1059 // Implementation of SafepointTracing
1060
1061 jlong SafepointTracing::_last_safepoint_begin_time_ns = 0;
1062 jlong SafepointTracing::_last_safepoint_sync_time_ns = 0;
1063 jlong SafepointTracing::_last_safepoint_cleanup_time_ns = 0;
1064 jlong SafepointTracing::_last_safepoint_end_time_ns = 0;
1065 jlong SafepointTracing::_last_app_time_ns = 0;
1066 int SafepointTracing::_nof_threads = 0;
1067 int SafepointTracing::_nof_running = 0;
1068 int SafepointTracing::_page_trap = 0;
1069 VM_Operation::VMOp_Type SafepointTracing::_current_type;
1070 jlong SafepointTracing::_max_sync_time = 0;
1071 jlong SafepointTracing::_max_vmop_time = 0;
1072 uint64_t SafepointTracing::_op_count[VM_Operation::VMOp_Terminating] = {0};
1073
1074 void SafepointTracing::init() {
1075 // Application start
1076 _last_safepoint_end_time_ns = os::javaTimeNanos();
1077 }
1078
1079 // Helper method to print the header.
1080 static void print_header(outputStream* st) {
1081 // The number of spaces is significant here, and should match the format
1082 // specifiers in print_statistics().
1083
1084 st->print("VM Operation "
1085 "[ threads: total initial_running ]"
1086 "[ time: sync cleanup vmop total ]");
1087
1088 st->print_cr(" page_trap_count");
1089 }
1090
1091 // This prints a nice table. To get the statistics to not shift due to the logging uptime
1092 // decorator, use the option as: -Xlog:safepoint+stats:[outputfile]:none
1093 void SafepointTracing::statistics_log() {
1094 LogTarget(Info, safepoint, stats) lt;
1095 assert (lt.is_enabled(), "should only be called when printing statistics is enabled");
1096 LogStream ls(lt);
1097
1098 static int _cur_stat_index = 0;
1099
1100 // Print header every 30 entries
1101 if ((_cur_stat_index % 30) == 0) {
1102 print_header(&ls);
1103 _cur_stat_index = 1; // wrap
1104 } else {
1105 _cur_stat_index++;
1106 }
1107
1108 ls.print("%-28s [ "
1109 INT32_FORMAT_W(8) " " INT32_FORMAT_W(8) " "
1110 "]",
1111 VM_Operation::name(_current_type),
1112 _nof_threads,
1113 _nof_running);
1114 ls.print("[ "
1115 INT64_FORMAT_W(10) " " INT64_FORMAT_W(10) " "
1116 INT64_FORMAT_W(10) " " INT64_FORMAT_W(10) " ]",
1117 (int64_t)(_last_safepoint_sync_time_ns - _last_safepoint_begin_time_ns),
1118 (int64_t)(_last_safepoint_cleanup_time_ns - _last_safepoint_sync_time_ns),
1119 (int64_t)(_last_safepoint_end_time_ns - _last_safepoint_cleanup_time_ns),
1120 (int64_t)(_last_safepoint_end_time_ns - _last_safepoint_begin_time_ns));
1121
1122 ls.print_cr(INT32_FORMAT_W(16), _page_trap);
1123 }
1124
1125 // This method will be called when VM exits. This tries to summarize the sampling.
1126 // Current thread may already be deleted, so don't use ResourceMark.
1127 void SafepointTracing::statistics_exit_log() {
1128 if (!log_is_enabled(Info, safepoint, stats)) {
1129 return;
1130 }
1131 for (int index = 0; index < VM_Operation::VMOp_Terminating; index++) {
1132 if (_op_count[index] != 0) {
1133 log_info(safepoint, stats)("%-28s" UINT64_FORMAT_W(10), VM_Operation::name(index),
1134 _op_count[index]);
1135 }
1136 }
1137
1138 log_info(safepoint, stats)("Maximum sync time " INT64_FORMAT" ns",
1139 (int64_t)(_max_sync_time));
1140 log_info(safepoint, stats)("Maximum vm operation time (except for Exit VM operation) "
1141 INT64_FORMAT " ns",
1142 (int64_t)(_max_vmop_time));
1143 }
1144
1145 void SafepointTracing::begin(VM_Operation::VMOp_Type type) {
1146 _op_count[type]++;
1147 _current_type = type;
1148
1149 // update the time stamp to begin recording safepoint time
1150 _last_safepoint_begin_time_ns = os::javaTimeNanos();
1151 _last_safepoint_sync_time_ns = 0;
1152 _last_safepoint_cleanup_time_ns = 0;
1153
1154 _last_app_time_ns = _last_safepoint_begin_time_ns - _last_safepoint_end_time_ns;
1155 _last_safepoint_end_time_ns = 0;
1156
1157 RuntimeService::record_safepoint_begin(_last_app_time_ns);
1158 }
1159
1160 void SafepointTracing::synchronized(int nof_threads, int nof_running, int traps) {
1161 _last_safepoint_sync_time_ns = os::javaTimeNanos();
1162 _nof_threads = nof_threads;
1163 _nof_running = nof_running;
1164 _page_trap = traps;
1165 RuntimeService::record_safepoint_synchronized(_last_safepoint_sync_time_ns - _last_safepoint_begin_time_ns);
1166 }
1167
1168 void SafepointTracing::cleanup() {
1169 _last_safepoint_cleanup_time_ns = os::javaTimeNanos();
1170 }
1171
1172 void SafepointTracing::end() {
1173 _last_safepoint_end_time_ns = os::javaTimeNanos();
1174
1175 if (_max_sync_time < (_last_safepoint_sync_time_ns - _last_safepoint_begin_time_ns)) {
1176 _max_sync_time = _last_safepoint_sync_time_ns - _last_safepoint_begin_time_ns;
1177 }
1178 if (_max_vmop_time < (_last_safepoint_end_time_ns - _last_safepoint_sync_time_ns)) {
1179 _max_vmop_time = _last_safepoint_end_time_ns - _last_safepoint_sync_time_ns;
1180 }
1181 if (log_is_enabled(Info, safepoint, stats)) {
1182 statistics_log();
1183 }
1184
1185 log_info(safepoint)(
1186 "Safepoint \"%s\", "
1187 "Time since last: " JLONG_FORMAT " ns, "
1188 "Reaching safepoint: " JLONG_FORMAT " ns, "
1189 "At safepoint: " JLONG_FORMAT " ns, "
1190 "Total: " JLONG_FORMAT " ns",
1191 VM_Operation::name(_current_type),
1192 _last_app_time_ns,
1193 _last_safepoint_cleanup_time_ns - _last_safepoint_begin_time_ns,
1194 _last_safepoint_end_time_ns - _last_safepoint_cleanup_time_ns,
1195 _last_safepoint_end_time_ns - _last_safepoint_begin_time_ns
1196 );
1197
1198 RuntimeService::record_safepoint_end(_last_safepoint_end_time_ns - _last_safepoint_cleanup_time_ns);
1199 }