1 /*
2 * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "cds/cdsConfig.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/javaThreadStatus.hpp"
30 #include "gc/shared/barrierSet.hpp"
31 #include "jfr/jfrEvents.hpp"
32 #include "jvm.h"
33 #include "jvmtifiles/jvmtiEnv.hpp"
34 #include "logging/log.hpp"
35 #include "memory/allocation.inline.hpp"
36 #include "memory/iterator.hpp"
37 #include "memory/resourceArea.hpp"
38 #include "nmt/memTracker.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "runtime/atomic.hpp"
41 #include "runtime/handles.inline.hpp"
42 #include "runtime/javaThread.inline.hpp"
43 #include "runtime/nonJavaThread.hpp"
44 #include "runtime/orderAccess.hpp"
45 #include "runtime/osThread.hpp"
46 #include "runtime/safepoint.hpp"
47 #include "runtime/safepointMechanism.inline.hpp"
48 #include "runtime/thread.inline.hpp"
49 #include "runtime/threadSMR.inline.hpp"
50 #include "utilities/macros.hpp"
51 #include "utilities/spinYield.hpp"
52 #if INCLUDE_JFR
53 #include "jfr/jfr.hpp"
54 #endif
55
56 #ifndef USE_LIBRARY_BASED_TLS_ONLY
57 // Current thread is maintained as a thread-local variable
58 THREAD_LOCAL Thread* Thread::_thr_current = nullptr;
59 #endif
60
61 // ======= Thread ========
62 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
63 // JavaThread
64
65 DEBUG_ONLY(Thread* Thread::_starting_thread = nullptr;)
66
67 Thread::Thread() {
68
69 DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
70
71 // stack and get_thread
72 set_stack_base(nullptr);
73 set_stack_size(0);
74 set_lgrp_id(-1);
75 DEBUG_ONLY(clear_suspendible_thread();)
76 DEBUG_ONLY(clear_indirectly_suspendible_thread();)
77 DEBUG_ONLY(clear_indirectly_safepoint_thread();)
78
79 // allocated data structures
80 set_osthread(nullptr);
81 set_resource_area(new (mtThread)ResourceArea());
82 DEBUG_ONLY(_current_resource_mark = nullptr;)
83 set_handle_area(new (mtThread) HandleArea(nullptr));
84 set_metadata_handles(new (mtClass) GrowableArray<Metadata*>(30, mtClass));
85 set_last_handle_mark(nullptr);
86 DEBUG_ONLY(_missed_ic_stub_refill_verifier = nullptr);
87
88 // Initial value of zero ==> never claimed.
89 _threads_do_token = 0;
90 _threads_hazard_ptr = nullptr;
91 _threads_list_ptr = nullptr;
92 _nested_threads_hazard_ptr_cnt = 0;
93 _rcu_counter = 0;
94
95 // the handle mark links itself to last_handle_mark
96 new HandleMark(this);
97
98 // plain initialization
99 debug_only(_owned_locks = nullptr;)
100 NOT_PRODUCT(_skip_gcalot = false;)
101 _jvmti_env_iteration_count = 0;
102 set_allocated_bytes(0);
103 _current_pending_raw_monitor = nullptr;
104 _vm_error_callbacks = nullptr;
105
106 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
107 // If we are dumping, keep ihashes constant. Note that during dumping we only
108 // ever run one java thread, and no other thread should generate ihashes either,
109 // so using a constant seed should work fine.
110 _hashStateX = CDSConfig::is_dumping_static_archive() ? 0x12345678 : os::random();
111 _hashStateY = 842502087;
112 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
113 _hashStateW = 273326509;
114
115 // Many of the following fields are effectively final - immutable
116 // Note that nascent threads can't use the Native Monitor-Mutex
117 // construct until the _MutexEvent is initialized ...
118 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
119 // we might instead use a stack of ParkEvents that we could provision on-demand.
120 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
121 // and ::Release()
122 _ParkEvent = ParkEvent::Allocate(this);
123
124 #ifdef CHECK_UNHANDLED_OOPS
125 if (CheckUnhandledOops) {
126 _unhandled_oops = new UnhandledOops(this);
127 }
128 #endif // CHECK_UNHANDLED_OOPS
129
130 // Notify the barrier set that a thread is being created. The initial
131 // thread is created before the barrier set is available. The call to
132 // BarrierSet::on_thread_create() for this thread is therefore deferred
133 // to BarrierSet::set_barrier_set().
134 BarrierSet* const barrier_set = BarrierSet::barrier_set();
135 if (barrier_set != nullptr) {
136 barrier_set->on_thread_create(this);
137 } else {
138 // Only the main thread should be created before the barrier set
139 // and that happens just before Thread::current is set. No other thread
140 // can attach as the VM is not created yet, so they can't execute this code.
141 // If the main thread creates other threads before the barrier set that is an error.
142 assert(Thread::current_or_null() == nullptr, "creating thread before barrier set");
143 }
144
145 MACOS_AARCH64_ONLY(DEBUG_ONLY(_wx_init = false));
146
147 _profile_vm_locks = false;
148 _profile_vm_calls = false;
149 _profile_vm_ops = false;
150 _profile_rt_calls = false;
151 _profile_upcalls = false;
152
153 _all_bc_counter_value = 0;
154 _clinit_bc_counter_value = 0;
155
156 _current_rt_call_timer = nullptr;
157 }
158
159 void Thread::initialize_tlab() {
160 if (UseTLAB) {
161 tlab().initialize();
162 }
163 }
164
165 void Thread::initialize_thread_current() {
166 #ifndef USE_LIBRARY_BASED_TLS_ONLY
167 assert(_thr_current == nullptr, "Thread::current already initialized");
168 _thr_current = this;
169 #endif
170 assert(ThreadLocalStorage::thread() == nullptr, "ThreadLocalStorage::thread already initialized");
171 ThreadLocalStorage::set_thread(this);
172 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
173 }
174
175 void Thread::clear_thread_current() {
176 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
177 #ifndef USE_LIBRARY_BASED_TLS_ONLY
178 _thr_current = nullptr;
179 #endif
180 ThreadLocalStorage::set_thread(nullptr);
181 }
182
183 void Thread::record_stack_base_and_size() {
184 // Note: at this point, Thread object is not yet initialized. Do not rely on
185 // any members being initialized. Do not rely on Thread::current() being set.
186 // If possible, refrain from doing anything which may crash or assert since
187 // quite probably those crash dumps will be useless.
188 address base;
189 size_t size;
190 os::current_stack_base_and_size(&base, &size);
191 set_stack_base(base);
192 set_stack_size(size);
193
194 // Set stack limits after thread is initialized.
195 if (is_Java_thread()) {
196 JavaThread::cast(this)->stack_overflow_state()->initialize(stack_base(), stack_end());
197 }
198 }
199
200 void Thread::register_thread_stack_with_NMT() {
201 MemTracker::record_thread_stack(stack_end(), stack_size());
202 }
203
204 void Thread::unregister_thread_stack_with_NMT() {
205 MemTracker::release_thread_stack(stack_end(), stack_size());
206 }
207
208 void Thread::call_run() {
209 DEBUG_ONLY(_run_state = CALL_RUN;)
210
211 // At this point, Thread object should be fully initialized and
212 // Thread::current() should be set.
213
214 assert(Thread::current_or_null() != nullptr, "current thread is unset");
215 assert(Thread::current_or_null() == this, "current thread is wrong");
216
217 // Perform common initialization actions
218
219 MACOS_AARCH64_ONLY(this->init_wx());
220
221 register_thread_stack_with_NMT();
222
223 JFR_ONLY(Jfr::on_thread_start(this);)
224
225 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
226 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
227 os::current_thread_id(), p2i(stack_end()),
228 p2i(stack_base()), stack_size()/1024);
229
230 // Perform <ChildClass> initialization actions
231 DEBUG_ONLY(_run_state = PRE_RUN;)
232 this->pre_run();
233
234 // Invoke <ChildClass>::run()
235 DEBUG_ONLY(_run_state = RUN;)
236 this->run();
237 // Returned from <ChildClass>::run(). Thread finished.
238
239 // Perform common tear-down actions
240
241 assert(Thread::current_or_null() != nullptr, "current thread is unset");
242 assert(Thread::current_or_null() == this, "current thread is wrong");
243
244 // Perform <ChildClass> tear-down actions
245 DEBUG_ONLY(_run_state = POST_RUN;)
246 this->post_run();
247
248 // Note: at this point the thread object may already have deleted itself,
249 // so from here on do not dereference *this*. Not all thread types currently
250 // delete themselves when they terminate. But no thread should ever be deleted
251 // asynchronously with respect to its termination - that is what _run_state can
252 // be used to check.
253
254 assert(Thread::current_or_null() == nullptr, "current thread still present");
255 }
256
257 Thread::~Thread() {
258
259 // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
260 // get started due to errors etc. Any active thread should at least reach post_run
261 // before it is deleted (usually in post_run()).
262 assert(_run_state == PRE_CALL_RUN ||
263 _run_state == POST_RUN, "Active Thread deleted before post_run(): "
264 "_run_state=%d", (int)_run_state);
265
266 // Notify the barrier set that a thread is being destroyed. Note that a barrier
267 // set might not be available if we encountered errors during bootstrapping.
268 BarrierSet* const barrier_set = BarrierSet::barrier_set();
269 if (barrier_set != nullptr) {
270 barrier_set->on_thread_destroy(this);
271 }
272
273 // deallocate data structures
274 delete resource_area();
275 // since the handle marks are using the handle area, we have to deallocated the root
276 // handle mark before deallocating the thread's handle area,
277 assert(last_handle_mark() != nullptr, "check we have an element");
278 delete last_handle_mark();
279 assert(last_handle_mark() == nullptr, "check we have reached the end");
280
281 ParkEvent::Release(_ParkEvent);
282 // Set to null as a termination indicator for has_terminated().
283 Atomic::store(&_ParkEvent, (ParkEvent*)nullptr);
284
285 delete handle_area();
286 delete metadata_handles();
287
288 // osthread() can be null, if creation of thread failed.
289 if (osthread() != nullptr) os::free_thread(osthread());
290
291 // Clear Thread::current if thread is deleting itself and it has not
292 // already been done. This must be done before the memory is deallocated.
293 // Needed to ensure JNI correctly detects non-attached threads.
294 if (this == Thread::current_or_null()) {
295 Thread::clear_thread_current();
296 }
297
298 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
299 }
300
301 #ifdef ASSERT
302 // A JavaThread is considered dangling if it not handshake-safe with respect to
303 // the current thread, it is not on a ThreadsList, or not at safepoint.
304 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
305 assert(!thread->is_Java_thread() ||
306 JavaThread::cast(thread)->is_handshake_safe_for(Thread::current()) ||
307 !JavaThread::cast(thread)->on_thread_list() ||
308 SafepointSynchronize::is_at_safepoint() ||
309 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock(JavaThread::cast(thread)),
310 "possibility of dangling Thread pointer");
311 }
312 #endif
313
314 // Is the target JavaThread protected by the calling Thread or by some other
315 // mechanism?
316 //
317 bool Thread::is_JavaThread_protected(const JavaThread* target) {
318 Thread* current_thread = Thread::current();
319
320 // Do the simplest check first:
321 if (SafepointSynchronize::is_at_safepoint()) {
322 // The target is protected since JavaThreads cannot exit
323 // while we're at a safepoint.
324 return true;
325 }
326
327 // If the target hasn't been started yet then it is trivially
328 // "protected". We assume the caller is the thread that will do
329 // the starting.
330 if (target->osthread() == nullptr || target->osthread()->get_state() <= INITIALIZED) {
331 return true;
332 }
333
334 // Now make the simple checks based on who the caller is:
335 if (current_thread == target || Threads_lock->owner() == current_thread) {
336 // Target JavaThread is self or calling thread owns the Threads_lock.
337 // Second check is the same as Threads_lock->owner_is_self(),
338 // but we already have the current thread so check directly.
339 return true;
340 }
341
342 // Check the ThreadsLists associated with the calling thread (if any)
343 // to see if one of them protects the target JavaThread:
344 if (is_JavaThread_protected_by_TLH(target)) {
345 return true;
346 }
347
348 // Use this debug code with -XX:+UseNewCode to diagnose locations that
349 // are missing a ThreadsListHandle or other protection mechanism:
350 // guarantee(!UseNewCode, "current_thread=" INTPTR_FORMAT " is not protecting target="
351 // INTPTR_FORMAT, p2i(current_thread), p2i(target));
352
353 // Note: Since 'target' isn't protected by a TLH, the call to
354 // target->is_handshake_safe_for() may crash, but we have debug bits so
355 // we'll be able to figure out what protection mechanism is missing.
356 assert(target->is_handshake_safe_for(current_thread), "JavaThread=" INTPTR_FORMAT
357 " is not protected and not handshake safe.", p2i(target));
358
359 // The target JavaThread is not protected so it is not safe to query:
360 return false;
361 }
362
363 // Is the target JavaThread protected by a ThreadsListHandle (TLH) associated
364 // with the calling Thread?
365 //
366 bool Thread::is_JavaThread_protected_by_TLH(const JavaThread* target) {
367 Thread* current_thread = Thread::current();
368
369 // Check the ThreadsLists associated with the calling thread (if any)
370 // to see if one of them protects the target JavaThread:
371 for (SafeThreadsListPtr* stlp = current_thread->_threads_list_ptr;
372 stlp != nullptr; stlp = stlp->previous()) {
373 if (stlp->list()->includes(target)) {
374 // The target JavaThread is protected by this ThreadsList:
375 return true;
376 }
377 }
378
379 // The target JavaThread is not protected by a TLH so it is not safe to query:
380 return false;
381 }
382
383 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
384 debug_only(check_for_dangling_thread_pointer(thread);)
385 // Can return an error!
386 (void)os::set_priority(thread, priority);
387 }
388
389
390 void Thread::start(Thread* thread) {
391 // Start is different from resume in that its safety is guaranteed by context or
392 // being called from a Java method synchronized on the Thread object.
393 if (thread->is_Java_thread()) {
394 // Initialize the thread state to RUNNABLE before starting this thread.
395 // Can not set it after the thread started because we do not know the
396 // exact thread state at that time. It could be in MONITOR_WAIT or
397 // in SLEEPING or some other state.
398 java_lang_Thread::set_thread_status(JavaThread::cast(thread)->threadObj(),
399 JavaThreadStatus::RUNNABLE);
400 }
401 os::start_thread(thread);
402 }
403
404 // GC Support
405 bool Thread::claim_par_threads_do(uintx claim_token) {
406 uintx token = _threads_do_token;
407 if (token != claim_token) {
408 uintx res = Atomic::cmpxchg(&_threads_do_token, token, claim_token);
409 if (res == token) {
410 return true;
411 }
412 guarantee(res == claim_token, "invariant");
413 }
414 return false;
415 }
416
417 void Thread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
418 // Do oop for ThreadShadow
419 f->do_oop((oop*)&_pending_exception);
420 handle_area()->oops_do(f);
421 }
422
423 // If the caller is a NamedThread, then remember, in the current scope,
424 // the given JavaThread in its _processed_thread field.
425 class RememberProcessedThread: public StackObj {
426 NamedThread* _cur_thr;
427 public:
428 RememberProcessedThread(Thread* thread) {
429 Thread* self = Thread::current();
430 if (self->is_Named_thread()) {
431 _cur_thr = (NamedThread *)self;
432 assert(_cur_thr->processed_thread() == nullptr, "nesting not supported");
433 _cur_thr->set_processed_thread(thread);
434 } else {
435 _cur_thr = nullptr;
436 }
437 }
438
439 ~RememberProcessedThread() {
440 if (_cur_thr) {
441 assert(_cur_thr->processed_thread() != nullptr, "nesting not supported");
442 _cur_thr->set_processed_thread(nullptr);
443 }
444 }
445 };
446
447 void Thread::oops_do(OopClosure* f, NMethodClosure* cf) {
448 // Record JavaThread to GC thread
449 RememberProcessedThread rpt(this);
450 oops_do_no_frames(f, cf);
451 oops_do_frames(f, cf);
452 }
453
454 void Thread::metadata_handles_do(void f(Metadata*)) {
455 // Only walk the Handles in Thread.
456 if (metadata_handles() != nullptr) {
457 for (int i = 0; i< metadata_handles()->length(); i++) {
458 f(metadata_handles()->at(i));
459 }
460 }
461 }
462
463 void Thread::print_on(outputStream* st, bool print_extended_info) const {
464 // get_priority assumes osthread initialized
465 if (osthread() != nullptr) {
466 int os_prio;
467 if (os::get_native_priority(this, &os_prio) == OS_OK) {
468 st->print("os_prio=%d ", os_prio);
469 }
470
471 st->print("cpu=%.2fms ",
472 (double)os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
473 );
474 st->print("elapsed=%.2fs ",
475 (double)_statistical_info.getElapsedTime() / 1000.0
476 );
477 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
478 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
479 st->print("allocated=" SIZE_FORMAT "%s ",
480 byte_size_in_proper_unit(allocated_bytes),
481 proper_unit_for_byte_size(allocated_bytes)
482 );
483 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
484 }
485
486 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
487 if (!is_Java_thread() || !JavaThread::cast(this)->is_vthread_mounted()) {
488 osthread()->print_on(st);
489 }
490 }
491 ThreadsSMRSupport::print_info_on(this, st);
492 st->print(" ");
493 debug_only(if (WizardMode) print_owned_locks_on(st);)
494 }
495
496 void Thread::print() const { print_on(tty); }
497
498 // Thread::print_on_error() is called by fatal error handler. Don't use
499 // any lock or allocate memory.
500 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
501 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
502
503 st->print("%s \"%s\"", type_name(), name());
504
505 OSThread* os_thr = osthread();
506 if (os_thr != nullptr) {
507 st->fill_to(67);
508 if (os_thr->get_state() != ZOMBIE) {
509 // Use raw field members for stack base/size as this could be
510 // called before a thread has run enough to initialize them.
511 st->print(" [id=%d, stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")]",
512 osthread()->thread_id(), p2i(_stack_base - _stack_size), p2i(_stack_base),
513 PROPERFMTARGS(_stack_size));
514 } else {
515 st->print(" terminated");
516 }
517 } else {
518 st->print(" unknown state (no osThread)");
519 }
520 ThreadsSMRSupport::print_info_on(this, st);
521 }
522
523 void Thread::print_value_on(outputStream* st) const {
524 if (is_Named_thread()) {
525 st->print(" \"%s\" ", name());
526 }
527 st->print(INTPTR_FORMAT, p2i(this)); // print address
528 }
529
530 #ifdef ASSERT
531 void Thread::print_owned_locks_on(outputStream* st) const {
532 Mutex* cur = _owned_locks;
533 if (cur == nullptr) {
534 st->print(" (no locks) ");
535 } else {
536 st->print_cr(" Locks owned:");
537 while (cur) {
538 cur->print_on(st);
539 cur = cur->next();
540 }
541 }
542 }
543 #endif // ASSERT
544
545 bool Thread::set_as_starting_thread() {
546 assert(_starting_thread == nullptr, "already initialized: "
547 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
548 // NOTE: this must be called inside the main thread.
549 DEBUG_ONLY(_starting_thread = this;)
550 return os::create_main_thread(JavaThread::cast(this));
551 }
552
553 // Ad-hoc mutual exclusion primitives: SpinLock
554 //
555 // We employ SpinLocks _only for low-contention, fixed-length
556 // short-duration critical sections where we're concerned
557 // about native mutex_t or HotSpot Mutex:: latency.
558 //
559 // TODO-FIXME: ListLock should be of type SpinLock.
560 // We should make this a 1st-class type, integrated into the lock
561 // hierarchy as leaf-locks. Critically, the SpinLock structure
562 // should have sufficient padding to avoid false-sharing and excessive
563 // cache-coherency traffic.
564
565
566 typedef volatile int SpinLockT;
567
568 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
569 if (Atomic::cmpxchg(adr, 0, 1) == 0) {
570 return; // normal fast-path return
571 }
572
573 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
574 int ctr = 0;
575 int Yields = 0;
576 for (;;) {
577 while (*adr != 0) {
578 ++ctr;
579 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
580 if (Yields > 5) {
581 os::naked_short_sleep(1);
582 } else {
583 os::naked_yield();
584 ++Yields;
585 }
586 } else {
587 SpinPause();
588 }
589 }
590 if (Atomic::cmpxchg(adr, 0, 1) == 0) return;
591 }
592 }
593
594 void Thread::SpinRelease(volatile int * adr) {
595 assert(*adr != 0, "invariant");
596 OrderAccess::fence(); // guarantee at least release consistency.
597 // Roach-motel semantics.
598 // It's safe if subsequent LDs and STs float "up" into the critical section,
599 // but prior LDs and STs within the critical section can't be allowed
600 // to reorder or float past the ST that releases the lock.
601 // Loads and stores in the critical section - which appear in program
602 // order before the store that releases the lock - must also appear
603 // before the store that releases the lock in memory visibility order.
604 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
605 // the ST of 0 into the lock-word which releases the lock, so fence
606 // more than covers this on all platforms.
607 *adr = 0;
608 }
609
610 const char* ProfileVMCallContext::name(PerfTraceTime* t) {
611 return t->name();
612 }
613
614 int ProfileVMCallContext::_perf_nested_runtime_calls_count = 0;
615
616 void ProfileVMCallContext::notify_nested_rt_call(PerfTraceTime* outer_timer, PerfTraceTime* inner_timer) {
617 log_debug(init)("Nested runtime call: inner=%s outer=%s", inner_timer->name(), outer_timer->name());
618 Atomic::inc(&ProfileVMCallContext::_perf_nested_runtime_calls_count);
619 }
620