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(MemTag mem_tag) {
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 (mem_tag) ResourceArea(mem_tag));
82 DEBUG_ONLY(_current_resource_mark = nullptr;)
83 set_handle_area(new (mem_tag) HandleArea(mem_tag, nullptr));
84 set_metadata_handles(new (mtClass) GrowableArray<Metadata*>(30, mtClass));
85 set_last_handle_mark(nullptr);
86
87 // Initial value of zero ==> never claimed.
88 _threads_do_token = 0;
89 _threads_hazard_ptr = nullptr;
90 _threads_list_ptr = nullptr;
91 _nested_threads_hazard_ptr_cnt = 0;
92 _rcu_counter = 0;
93
94 // the handle mark links itself to last_handle_mark
95 new HandleMark(this);
96
97 // plain initialization
98 debug_only(_owned_locks = nullptr;)
99 NOT_PRODUCT(_skip_gcalot = false;)
100 _jvmti_env_iteration_count = 0;
101 set_allocated_bytes(0);
102 _current_pending_raw_monitor = nullptr;
103 _vm_error_callbacks = nullptr;
104
105 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
106 // If we are dumping, keep ihashes constant. Note that during dumping we only
107 // ever run one java thread, and no other thread should generate ihashes either,
108 // so using a constant seed should work fine.
109 _hashStateX = CDSConfig::is_dumping_static_archive() ? 0x12345678 : os::random();
110 _hashStateY = 842502087;
111 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
112 _hashStateW = 273326509;
113
114 // Many of the following fields are effectively final - immutable
115 // Note that nascent threads can't use the Native Monitor-Mutex
116 // construct until the _MutexEvent is initialized ...
117 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
118 // we might instead use a stack of ParkEvents that we could provision on-demand.
119 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
120 // and ::Release()
121 _ParkEvent = ParkEvent::Allocate(this);
122
123 #ifdef CHECK_UNHANDLED_OOPS
124 if (CheckUnhandledOops) {
125 _unhandled_oops = new UnhandledOops(this);
126 }
127 #endif // CHECK_UNHANDLED_OOPS
128
129 // Notify the barrier set that a thread is being created. The initial
130 // thread is created before the barrier set is available. The call to
131 // BarrierSet::on_thread_create() for this thread is therefore deferred
132 // to BarrierSet::set_barrier_set().
133 BarrierSet* const barrier_set = BarrierSet::barrier_set();
134 if (barrier_set != nullptr) {
135 barrier_set->on_thread_create(this);
136 } else {
137 // Only the main thread should be created before the barrier set
138 // and that happens just before Thread::current is set. No other thread
139 // can attach as the VM is not created yet, so they can't execute this code.
140 // If the main thread creates other threads before the barrier set that is an error.
141 assert(Thread::current_or_null() == nullptr, "creating thread before barrier set");
142 }
143
144 MACOS_AARCH64_ONLY(DEBUG_ONLY(_wx_init = false));
145
146 _profile_vm_locks = false;
147 _profile_vm_calls = false;
148 _profile_vm_ops = false;
149 _profile_rt_calls = false;
150 _profile_upcalls = false;
151
152 _all_bc_counter_value = 0;
153 _clinit_bc_counter_value = 0;
154
155 _current_rt_call_timer = nullptr;
156 }
157
158 #ifdef ASSERT
159 address Thread::stack_base() const {
160 // Note: can't report Thread::name() here as that can require a ResourceMark which we
161 // can't use because this gets called too early in the thread initialization.
162 assert(_stack_base != nullptr, "Stack base not yet set for thread id:%d (0 if not set)",
163 osthread() != nullptr ? osthread()->thread_id() : 0);
164 return _stack_base;
165 }
166 #endif
167
168 void Thread::initialize_tlab() {
169 if (UseTLAB) {
170 tlab().initialize();
171 }
172 }
173
174 void Thread::initialize_thread_current() {
175 #ifndef USE_LIBRARY_BASED_TLS_ONLY
176 assert(_thr_current == nullptr, "Thread::current already initialized");
177 _thr_current = this;
178 #endif
179 assert(ThreadLocalStorage::thread() == nullptr, "ThreadLocalStorage::thread already initialized");
180 ThreadLocalStorage::set_thread(this);
181 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
182 }
183
184 void Thread::clear_thread_current() {
185 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
186 #ifndef USE_LIBRARY_BASED_TLS_ONLY
187 _thr_current = nullptr;
188 #endif
189 ThreadLocalStorage::set_thread(nullptr);
190 }
191
192 void Thread::record_stack_base_and_size() {
193 // Note: at this point, Thread object is not yet initialized. Do not rely on
194 // any members being initialized. Do not rely on Thread::current() being set.
195 // If possible, refrain from doing anything which may crash or assert since
196 // quite probably those crash dumps will be useless.
197 address base;
198 size_t size;
199 os::current_stack_base_and_size(&base, &size);
200 set_stack_base(base);
201 set_stack_size(size);
202
203 // Set stack limits after thread is initialized.
204 if (is_Java_thread()) {
205 JavaThread::cast(this)->stack_overflow_state()->initialize(stack_base(), stack_end());
206 }
207 }
208
209 void Thread::register_thread_stack_with_NMT() {
210 MemTracker::record_thread_stack(stack_end(), stack_size());
211 }
212
213 void Thread::unregister_thread_stack_with_NMT() {
214 MemTracker::release_thread_stack(stack_end(), stack_size());
215 }
216
217 void Thread::call_run() {
218 DEBUG_ONLY(_run_state = CALL_RUN;)
219
220 // At this point, Thread object should be fully initialized and
221 // Thread::current() should be set.
222
223 assert(Thread::current_or_null() != nullptr, "current thread is unset");
224 assert(Thread::current_or_null() == this, "current thread is wrong");
225
226 // Perform common initialization actions
227
228 MACOS_AARCH64_ONLY(this->init_wx());
229
230 register_thread_stack_with_NMT();
231
232 JFR_ONLY(Jfr::on_thread_start(this);)
233
234 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
235 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
236 os::current_thread_id(), p2i(stack_end()),
237 p2i(stack_base()), stack_size()/1024);
238
239 // Perform <ChildClass> initialization actions
240 DEBUG_ONLY(_run_state = PRE_RUN;)
241 this->pre_run();
242
243 // Invoke <ChildClass>::run()
244 DEBUG_ONLY(_run_state = RUN;)
245 this->run();
246 // Returned from <ChildClass>::run(). Thread finished.
247
248 // Perform common tear-down actions
249
250 assert(Thread::current_or_null() != nullptr, "current thread is unset");
251 assert(Thread::current_or_null() == this, "current thread is wrong");
252
253 // Perform <ChildClass> tear-down actions
254 DEBUG_ONLY(_run_state = POST_RUN;)
255 this->post_run();
256
257 // Note: at this point the thread object may already have deleted itself,
258 // so from here on do not dereference *this*. Not all thread types currently
259 // delete themselves when they terminate. But no thread should ever be deleted
260 // asynchronously with respect to its termination - that is what _run_state can
261 // be used to check.
262
263 assert(Thread::current_or_null() == nullptr, "current thread still present");
264 }
265
266 Thread::~Thread() {
267
268 // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
269 // get started due to errors etc. Any active thread should at least reach post_run
270 // before it is deleted (usually in post_run()).
271 assert(_run_state == PRE_CALL_RUN ||
272 _run_state == POST_RUN, "Active Thread deleted before post_run(): "
273 "_run_state=%d", (int)_run_state);
274
275 // Notify the barrier set that a thread is being destroyed. Note that a barrier
276 // set might not be available if we encountered errors during bootstrapping.
277 BarrierSet* const barrier_set = BarrierSet::barrier_set();
278 if (barrier_set != nullptr) {
279 barrier_set->on_thread_destroy(this);
280 }
281
282 // deallocate data structures
283 delete resource_area();
284 // since the handle marks are using the handle area, we have to deallocated the root
285 // handle mark before deallocating the thread's handle area,
286 assert(last_handle_mark() != nullptr, "check we have an element");
287 delete last_handle_mark();
288 assert(last_handle_mark() == nullptr, "check we have reached the end");
289
290 ParkEvent::Release(_ParkEvent);
291 // Set to null as a termination indicator for has_terminated().
292 Atomic::store(&_ParkEvent, (ParkEvent*)nullptr);
293
294 delete handle_area();
295 delete metadata_handles();
296
297 // osthread() can be null, if creation of thread failed.
298 if (osthread() != nullptr) os::free_thread(osthread());
299
300 // Clear Thread::current if thread is deleting itself and it has not
301 // already been done. This must be done before the memory is deallocated.
302 // Needed to ensure JNI correctly detects non-attached threads.
303 if (this == Thread::current_or_null()) {
304 Thread::clear_thread_current();
305 }
306
307 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
308 }
309
310 #ifdef ASSERT
311 // A JavaThread is considered dangling if it not handshake-safe with respect to
312 // the current thread, it is not on a ThreadsList, or not at safepoint.
313 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
314 assert(!thread->is_Java_thread() ||
315 JavaThread::cast(thread)->is_handshake_safe_for(Thread::current()) ||
316 !JavaThread::cast(thread)->on_thread_list() ||
317 SafepointSynchronize::is_at_safepoint() ||
318 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock(JavaThread::cast(thread)),
319 "possibility of dangling Thread pointer");
320 }
321 #endif
322
323 // Is the target JavaThread protected by the calling Thread or by some other
324 // mechanism?
325 //
326 bool Thread::is_JavaThread_protected(const JavaThread* target) {
327 Thread* current_thread = Thread::current();
328
329 // Do the simplest check first:
330 if (SafepointSynchronize::is_at_safepoint()) {
331 // The target is protected since JavaThreads cannot exit
332 // while we're at a safepoint.
333 return true;
334 }
335
336 // If the target hasn't been started yet then it is trivially
337 // "protected". We assume the caller is the thread that will do
338 // the starting.
339 if (target->osthread() == nullptr || target->osthread()->get_state() <= INITIALIZED) {
340 return true;
341 }
342
343 // Now make the simple checks based on who the caller is:
344 if (current_thread == target || Threads_lock->owner() == current_thread) {
345 // Target JavaThread is self or calling thread owns the Threads_lock.
346 // Second check is the same as Threads_lock->owner_is_self(),
347 // but we already have the current thread so check directly.
348 return true;
349 }
350
351 // Check the ThreadsLists associated with the calling thread (if any)
352 // to see if one of them protects the target JavaThread:
353 if (is_JavaThread_protected_by_TLH(target)) {
354 return true;
355 }
356
357 // Use this debug code with -XX:+UseNewCode to diagnose locations that
358 // are missing a ThreadsListHandle or other protection mechanism:
359 // guarantee(!UseNewCode, "current_thread=" INTPTR_FORMAT " is not protecting target="
360 // INTPTR_FORMAT, p2i(current_thread), p2i(target));
361
362 // Note: Since 'target' isn't protected by a TLH, the call to
363 // target->is_handshake_safe_for() may crash, but we have debug bits so
364 // we'll be able to figure out what protection mechanism is missing.
365 assert(target->is_handshake_safe_for(current_thread), "JavaThread=" INTPTR_FORMAT
366 " is not protected and not handshake safe.", p2i(target));
367
368 // The target JavaThread is not protected so it is not safe to query:
369 return false;
370 }
371
372 // Is the target JavaThread protected by a ThreadsListHandle (TLH) associated
373 // with the calling Thread?
374 //
375 bool Thread::is_JavaThread_protected_by_TLH(const JavaThread* target) {
376 Thread* current_thread = Thread::current();
377
378 // Check the ThreadsLists associated with the calling thread (if any)
379 // to see if one of them protects the target JavaThread:
380 for (SafeThreadsListPtr* stlp = current_thread->_threads_list_ptr;
381 stlp != nullptr; stlp = stlp->previous()) {
382 if (stlp->list()->includes(target)) {
383 // The target JavaThread is protected by this ThreadsList:
384 return true;
385 }
386 }
387
388 // The target JavaThread is not protected by a TLH so it is not safe to query:
389 return false;
390 }
391
392 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
393 debug_only(check_for_dangling_thread_pointer(thread);)
394 // Can return an error!
395 (void)os::set_priority(thread, priority);
396 }
397
398
399 void Thread::start(Thread* thread) {
400 // Start is different from resume in that its safety is guaranteed by context or
401 // being called from a Java method synchronized on the Thread object.
402 if (thread->is_Java_thread()) {
403 // Initialize the thread state to RUNNABLE before starting this thread.
404 // Can not set it after the thread started because we do not know the
405 // exact thread state at that time. It could be in MONITOR_WAIT or
406 // in SLEEPING or some other state.
407 java_lang_Thread::set_thread_status(JavaThread::cast(thread)->threadObj(),
408 JavaThreadStatus::RUNNABLE);
409 }
410 os::start_thread(thread);
411 }
412
413 // GC Support
414 bool Thread::claim_par_threads_do(uintx claim_token) {
415 uintx token = _threads_do_token;
416 if (token != claim_token) {
417 uintx res = Atomic::cmpxchg(&_threads_do_token, token, claim_token);
418 if (res == token) {
419 return true;
420 }
421 guarantee(res == claim_token, "invariant");
422 }
423 return false;
424 }
425
426 void Thread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
427 // Do oop for ThreadShadow
428 f->do_oop((oop*)&_pending_exception);
429 handle_area()->oops_do(f);
430 }
431
432 // If the caller is a NamedThread, then remember, in the current scope,
433 // the given JavaThread in its _processed_thread field.
434 class RememberProcessedThread: public StackObj {
435 NamedThread* _cur_thr;
436 public:
437 RememberProcessedThread(Thread* thread) {
438 Thread* self = Thread::current();
439 if (self->is_Named_thread()) {
440 _cur_thr = (NamedThread *)self;
441 assert(_cur_thr->processed_thread() == nullptr, "nesting not supported");
442 _cur_thr->set_processed_thread(thread);
443 } else {
444 _cur_thr = nullptr;
445 }
446 }
447
448 ~RememberProcessedThread() {
449 if (_cur_thr) {
450 assert(_cur_thr->processed_thread() != nullptr, "nesting not supported");
451 _cur_thr->set_processed_thread(nullptr);
452 }
453 }
454 };
455
456 void Thread::oops_do(OopClosure* f, NMethodClosure* cf) {
457 // Record JavaThread to GC thread
458 RememberProcessedThread rpt(this);
459 oops_do_no_frames(f, cf);
460 oops_do_frames(f, cf);
461 }
462
463 void Thread::metadata_handles_do(void f(Metadata*)) {
464 // Only walk the Handles in Thread.
465 if (metadata_handles() != nullptr) {
466 for (int i = 0; i< metadata_handles()->length(); i++) {
467 f(metadata_handles()->at(i));
468 }
469 }
470 }
471
472 void Thread::print_on(outputStream* st, bool print_extended_info) const {
473 // get_priority assumes osthread initialized
474 if (osthread() != nullptr) {
475 int os_prio;
476 if (os::get_native_priority(this, &os_prio) == OS_OK) {
477 st->print("os_prio=%d ", os_prio);
478 }
479
480 st->print("cpu=%.2fms ",
481 (double)os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
482 );
483 st->print("elapsed=%.2fs ",
484 (double)_statistical_info.getElapsedTime() / 1000.0
485 );
486 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
487 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
488 st->print("allocated=" SIZE_FORMAT "%s ",
489 byte_size_in_proper_unit(allocated_bytes),
490 proper_unit_for_byte_size(allocated_bytes)
491 );
492 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
493 }
494
495 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
496 if (!is_Java_thread() || !JavaThread::cast(this)->is_vthread_mounted()) {
497 osthread()->print_on(st);
498 }
499 }
500 ThreadsSMRSupport::print_info_on(this, st);
501 st->print(" ");
502 debug_only(if (WizardMode) print_owned_locks_on(st);)
503 }
504
505 void Thread::print() const { print_on(tty); }
506
507 // Thread::print_on_error() is called by fatal error handler. Don't use
508 // any lock or allocate memory.
509 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
510 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
511
512 st->print("%s \"%s\"", type_name(), name());
513
514 OSThread* os_thr = osthread();
515 if (os_thr != nullptr) {
516 st->fill_to(67);
517 if (os_thr->get_state() != ZOMBIE) {
518 // Use raw field members for stack base/size as this could be
519 // called before a thread has run enough to initialize them.
520 st->print(" [id=%d, stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")]",
521 osthread()->thread_id(), p2i(_stack_base - _stack_size), p2i(_stack_base),
522 PROPERFMTARGS(_stack_size));
523 } else {
524 st->print(" terminated");
525 }
526 } else {
527 st->print(" unknown state (no osThread)");
528 }
529 ThreadsSMRSupport::print_info_on(this, st);
530 }
531
532 void Thread::print_value_on(outputStream* st) const {
533 if (is_Named_thread()) {
534 st->print(" \"%s\" ", name());
535 }
536 st->print(INTPTR_FORMAT, p2i(this)); // print address
537 }
538
539 #ifdef ASSERT
540 void Thread::print_owned_locks_on(outputStream* st) const {
541 Mutex* cur = _owned_locks;
542 if (cur == nullptr) {
543 st->print(" (no locks) ");
544 } else {
545 st->print_cr(" Locks owned:");
546 while (cur) {
547 cur->print_on(st);
548 cur = cur->next();
549 }
550 }
551 }
552 #endif // ASSERT
553
554 bool Thread::set_as_starting_thread() {
555 assert(_starting_thread == nullptr, "already initialized: "
556 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
557 // NOTE: this must be called inside the main thread.
558 DEBUG_ONLY(_starting_thread = this;)
559 return os::create_main_thread(JavaThread::cast(this));
560 }
561
562 // Ad-hoc mutual exclusion primitives: SpinLock
563 //
564 // We employ SpinLocks _only for low-contention, fixed-length
565 // short-duration critical sections where we're concerned
566 // about native mutex_t or HotSpot Mutex:: latency.
567 //
568 // TODO-FIXME: ListLock should be of type SpinLock.
569 // We should make this a 1st-class type, integrated into the lock
570 // hierarchy as leaf-locks. Critically, the SpinLock structure
571 // should have sufficient padding to avoid false-sharing and excessive
572 // cache-coherency traffic.
573
574
575 typedef volatile int SpinLockT;
576
577 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
578 if (Atomic::cmpxchg(adr, 0, 1) == 0) {
579 return; // normal fast-path return
580 }
581
582 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
583 int ctr = 0;
584 int Yields = 0;
585 for (;;) {
586 while (*adr != 0) {
587 ++ctr;
588 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
589 if (Yields > 5) {
590 os::naked_short_sleep(1);
591 } else {
592 os::naked_yield();
593 ++Yields;
594 }
595 } else {
596 SpinPause();
597 }
598 }
599 if (Atomic::cmpxchg(adr, 0, 1) == 0) return;
600 }
601 }
602
603 void Thread::SpinRelease(volatile int * adr) {
604 assert(*adr != 0, "invariant");
605 OrderAccess::fence(); // guarantee at least release consistency.
606 // Roach-motel semantics.
607 // It's safe if subsequent LDs and STs float "up" into the critical section,
608 // but prior LDs and STs within the critical section can't be allowed
609 // to reorder or float past the ST that releases the lock.
610 // Loads and stores in the critical section - which appear in program
611 // order before the store that releases the lock - must also appear
612 // before the store that releases the lock in memory visibility order.
613 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
614 // the ST of 0 into the lock-word which releases the lock, so fence
615 // more than covers this on all platforms.
616 *adr = 0;
617 }
618
619 const char* ProfileVMCallContext::name(PerfTraceTime* t) {
620 return t->name();
621 }
622
623 int ProfileVMCallContext::_perf_nested_runtime_calls_count = 0;
624
625 void ProfileVMCallContext::notify_nested_rt_call(PerfTraceTime* outer_timer, PerfTraceTime* inner_timer) {
626 log_debug(init)("Nested runtime call: inner=%s outer=%s", inner_timer->name(), outer_timer->name());
627 Atomic::inc(&ProfileVMCallContext::_perf_nested_runtime_calls_count);
628 }
629