1 /*
2 * Copyright (c) 1997, 2018, 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 "jvm.h"
27 #include "classfile/classLoader.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/moduleEntry.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "classfile/vmSymbols.hpp"
32 #include "code/codeCache.hpp"
33 #include "code/scopeDesc.hpp"
34 #include "compiler/compileBroker.hpp"
35 #include "compiler/compileTask.hpp"
36 #include "gc/shared/barrierSet.hpp"
37 #include "gc/shared/gcId.hpp"
38 #include "gc/shared/gcLocker.inline.hpp"
39 #include "gc/shared/workgroup.hpp"
40 #include "interpreter/interpreter.hpp"
41 #include "interpreter/linkResolver.hpp"
42 #include "interpreter/oopMapCache.hpp"
43 #include "jfr/jfrEvents.hpp"
44 #include "jfr/support/jfrThreadId.hpp"
45 #include "jvmtifiles/jvmtiEnv.hpp"
46 #include "logging/log.hpp"
47 #include "logging/logConfiguration.hpp"
48 #include "logging/logStream.hpp"
49 #include "memory/allocation.inline.hpp"
50 #include "memory/metaspaceShared.hpp"
51 #include "memory/oopFactory.hpp"
52 #include "memory/resourceArea.hpp"
53 #include "memory/universe.hpp"
54 #include "oops/access.inline.hpp"
55 #include "oops/instanceKlass.hpp"
56 #include "oops/objArrayOop.hpp"
57 #include "oops/oop.inline.hpp"
58 #include "oops/symbol.hpp"
59 #include "oops/typeArrayOop.inline.hpp"
60 #include "oops/verifyOopClosure.hpp"
61 #include "prims/jvm_misc.hpp"
62 #include "prims/jvmtiExport.hpp"
63 #include "prims/jvmtiThreadState.hpp"
64 #include "prims/privilegedStack.hpp"
65 #include "runtime/arguments.hpp"
66 #include "runtime/atomic.hpp"
67 #include "runtime/biasedLocking.hpp"
68 #include "runtime/flags/jvmFlagConstraintList.hpp"
69 #include "runtime/flags/jvmFlagRangeList.hpp"
70 #include "runtime/flags/jvmFlagWriteableList.hpp"
71 #include "runtime/deoptimization.hpp"
72 #include "runtime/frame.inline.hpp"
73 #include "runtime/handshake.hpp"
74 #include "runtime/init.hpp"
75 #include "runtime/interfaceSupport.inline.hpp"
76 #include "runtime/java.hpp"
77 #include "runtime/javaCalls.hpp"
78 #include "runtime/jniHandles.inline.hpp"
79 #include "runtime/jniPeriodicChecker.hpp"
80 #include "runtime/memprofiler.hpp"
81 #include "runtime/mutexLocker.hpp"
82 #include "runtime/objectMonitor.hpp"
83 #include "runtime/orderAccess.hpp"
84 #include "runtime/osThread.hpp"
85 #include "runtime/prefetch.inline.hpp"
86 #include "runtime/safepoint.hpp"
87 #include "runtime/safepointMechanism.inline.hpp"
88 #include "runtime/sharedRuntime.hpp"
89 #include "runtime/statSampler.hpp"
90 #include "runtime/stubRoutines.hpp"
91 #include "runtime/sweeper.hpp"
92 #include "runtime/task.hpp"
93 #include "runtime/thread.inline.hpp"
94 #include "runtime/threadCritical.hpp"
95 #include "runtime/threadSMR.inline.hpp"
96 #include "runtime/threadStatisticalInfo.hpp"
97 #include "runtime/timer.hpp"
98 #include "runtime/timerTrace.hpp"
99 #include "runtime/vframe.inline.hpp"
100 #include "runtime/vframeArray.hpp"
101 #include "runtime/vframe_hp.hpp"
102 #include "runtime/vmThread.hpp"
103 #include "runtime/vm_operations.hpp"
104 #include "runtime/vm_version.hpp"
105 #include "services/attachListener.hpp"
106 #include "services/management.hpp"
107 #include "services/memTracker.hpp"
108 #include "services/threadService.hpp"
109 #include "utilities/align.hpp"
110 #include "utilities/copy.hpp"
111 #include "utilities/defaultStream.hpp"
112 #include "utilities/dtrace.hpp"
113 #include "utilities/events.hpp"
114 #include "utilities/macros.hpp"
115 #include "utilities/preserveException.hpp"
116 #include "utilities/vmError.hpp"
117 #if INCLUDE_JVMCI
118 #include "jvmci/jvmciCompiler.hpp"
119 #include "jvmci/jvmciRuntime.hpp"
120 #include "logging/logHandle.hpp"
121 #endif
122 #ifdef COMPILER1
123 #include "c1/c1_Compiler.hpp"
124 #endif
125 #ifdef COMPILER2
126 #include "opto/c2compiler.hpp"
127 #include "opto/idealGraphPrinter.hpp"
128 #endif
129 #if INCLUDE_RTM_OPT
130 #include "runtime/rtmLocking.hpp"
131 #endif
132 #if INCLUDE_JFR
133 #include "jfr/jfr.hpp"
134 #endif
135
136 // Initialization after module runtime initialization
137 void universe_post_module_init(); // must happen after call_initPhase2
138
139 #ifdef DTRACE_ENABLED
140
141 // Only bother with this argument setup if dtrace is available
142
143 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
144 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
145
146 #define DTRACE_THREAD_PROBE(probe, javathread) \
147 { \
148 ResourceMark rm(this); \
149 int len = 0; \
150 const char* name = (javathread)->get_thread_name(); \
151 len = strlen(name); \
152 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
153 (char *) name, len, \
154 java_lang_Thread::thread_id((javathread)->threadObj()), \
155 (uintptr_t) (javathread)->osthread()->thread_id(), \
156 java_lang_Thread::is_daemon((javathread)->threadObj())); \
157 }
158
159 #else // ndef DTRACE_ENABLED
160
161 #define DTRACE_THREAD_PROBE(probe, javathread)
162
163 #endif // ndef DTRACE_ENABLED
164
165 #ifndef USE_LIBRARY_BASED_TLS_ONLY
166 // Current thread is maintained as a thread-local variable
167 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
168 #endif
169 // Class hierarchy
170 // - Thread
171 // - VMThread
172 // - WatcherThread
173 // - ConcurrentMarkSweepThread
174 // - JavaThread
175 // - CompilerThread
176
177 // ======= Thread ========
178 // Support for forcing alignment of thread objects for biased locking
179 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
180 if (UseBiasedLocking) {
181 const int alignment = markOopDesc::biased_lock_alignment;
182 size_t aligned_size = size + (alignment - sizeof(intptr_t));
183 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
184 : AllocateHeap(aligned_size, flags, CURRENT_PC,
185 AllocFailStrategy::RETURN_NULL);
186 void* aligned_addr = align_up(real_malloc_addr, alignment);
187 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
188 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
189 "JavaThread alignment code overflowed allocated storage");
190 if (aligned_addr != real_malloc_addr) {
191 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
192 p2i(real_malloc_addr),
193 p2i(aligned_addr));
194 }
195 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
196 return aligned_addr;
197 } else {
198 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
199 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
200 }
201 }
202
203 void Thread::operator delete(void* p) {
204 if (UseBiasedLocking) {
205 FreeHeap(((Thread*) p)->_real_malloc_address);
206 } else {
207 FreeHeap(p);
208 }
209 }
210
211 void JavaThread::smr_delete() {
212 if (_on_thread_list) {
213 ThreadsSMRSupport::smr_delete(this);
214 } else {
215 delete this;
216 }
217 }
218
219 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
220 // JavaThread
221
222
223 Thread::Thread() {
224 // stack and get_thread
225 set_stack_base(NULL);
226 set_stack_size(0);
227 set_self_raw_id(0);
228 set_lgrp_id(-1);
229 DEBUG_ONLY(clear_suspendible_thread();)
230
231 // allocated data structures
232 set_osthread(NULL);
233 set_resource_area(new (mtThread)ResourceArea());
234 DEBUG_ONLY(_current_resource_mark = NULL;)
235 set_handle_area(new (mtThread) HandleArea(NULL));
236 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
237 set_active_handles(NULL);
238 set_free_handle_block(NULL);
239 set_last_handle_mark(NULL);
240
241 // This initial value ==> never claimed.
242 _oops_do_parity = 0;
243 _threads_hazard_ptr = NULL;
244 _threads_list_ptr = NULL;
245 _nested_threads_hazard_ptr_cnt = 0;
246 _rcu_counter = 0;
247
248 // the handle mark links itself to last_handle_mark
249 new HandleMark(this);
250
251 // plain initialization
252 debug_only(_owned_locks = NULL;)
253 debug_only(_allow_allocation_count = 0;)
254 NOT_PRODUCT(_allow_safepoint_count = 0;)
255 NOT_PRODUCT(_skip_gcalot = false;)
256 _jvmti_env_iteration_count = 0;
257 set_allocated_bytes(0);
258 _vm_operation_started_count = 0;
259 _vm_operation_completed_count = 0;
260 _current_pending_monitor = NULL;
261 _current_pending_monitor_is_from_java = true;
262 _current_waiting_monitor = NULL;
263 _num_nested_signal = 0;
264 omFreeList = NULL;
265 omFreeCount = 0;
266 omFreeProvision = 32;
267 omInUseList = NULL;
268 omInUseCount = 0;
269
270 #ifdef ASSERT
271 _visited_for_critical_count = false;
272 #endif
273
274 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
275 Monitor::_safepoint_check_sometimes);
276 _suspend_flags = 0;
277
278 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
279 _hashStateX = os::random();
280 _hashStateY = 842502087;
281 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
282 _hashStateW = 273326509;
283
284 _OnTrap = 0;
285 _schedctl = NULL;
286 _Stalled = 0;
287 _TypeTag = 0x2BAD;
288
289 // Many of the following fields are effectively final - immutable
290 // Note that nascent threads can't use the Native Monitor-Mutex
291 // construct until the _MutexEvent is initialized ...
292 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
293 // we might instead use a stack of ParkEvents that we could provision on-demand.
294 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
295 // and ::Release()
296 _ParkEvent = ParkEvent::Allocate(this);
297 _SleepEvent = ParkEvent::Allocate(this);
298 _MutexEvent = ParkEvent::Allocate(this);
299 _MuxEvent = ParkEvent::Allocate(this);
300
301 #ifdef CHECK_UNHANDLED_OOPS
302 if (CheckUnhandledOops) {
303 _unhandled_oops = new UnhandledOops(this);
304 }
305 #endif // CHECK_UNHANDLED_OOPS
306 #ifdef ASSERT
307 if (UseBiasedLocking) {
308 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
309 assert(this == _real_malloc_address ||
310 this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment),
311 "bug in forced alignment of thread objects");
312 }
313 #endif // ASSERT
314
315 // Notify the barrier set that a thread is being created. Note that the
316 // main thread is created before a barrier set is available. The call to
317 // BarrierSet::on_thread_create() for the main thread is therefore deferred
318 // until it calls BarrierSet::set_barrier_set().
319 BarrierSet* const barrier_set = BarrierSet::barrier_set();
320 if (barrier_set != NULL) {
321 barrier_set->on_thread_create(this);
322 }
323 }
324
325 void Thread::initialize_thread_current() {
326 #ifndef USE_LIBRARY_BASED_TLS_ONLY
327 assert(_thr_current == NULL, "Thread::current already initialized");
328 _thr_current = this;
329 #endif
330 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
331 ThreadLocalStorage::set_thread(this);
332 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
333 }
334
335 void Thread::clear_thread_current() {
336 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
337 #ifndef USE_LIBRARY_BASED_TLS_ONLY
338 _thr_current = NULL;
339 #endif
340 ThreadLocalStorage::set_thread(NULL);
341 }
342
343 void Thread::record_stack_base_and_size() {
344 set_stack_base(os::current_stack_base());
345 set_stack_size(os::current_stack_size());
346 // CR 7190089: on Solaris, primordial thread's stack is adjusted
347 // in initialize_thread(). Without the adjustment, stack size is
348 // incorrect if stack is set to unlimited (ulimit -s unlimited).
349 // So far, only Solaris has real implementation of initialize_thread().
350 //
351 // set up any platform-specific state.
352 os::initialize_thread(this);
353
354 // Set stack limits after thread is initialized.
355 if (is_Java_thread()) {
356 ((JavaThread*) this)->set_stack_overflow_limit();
357 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
358 }
359 #if INCLUDE_NMT
360 // record thread's native stack, stack grows downward
361 MemTracker::record_thread_stack(stack_end(), stack_size());
362 #endif // INCLUDE_NMT
363 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
364 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
365 os::current_thread_id(), p2i(stack_base() - stack_size()),
366 p2i(stack_base()), stack_size()/1024);
367 }
368
369
370 Thread::~Thread() {
371 JFR_ONLY(Jfr::on_thread_destruct(this);)
372
373 // Notify the barrier set that a thread is being destroyed. Note that a barrier
374 // set might not be available if we encountered errors during bootstrapping.
375 BarrierSet* const barrier_set = BarrierSet::barrier_set();
376 if (barrier_set != NULL) {
377 barrier_set->on_thread_destroy(this);
378 }
379
380
381 // stack_base can be NULL if the thread is never started or exited before
382 // record_stack_base_and_size called. Although, we would like to ensure
383 // that all started threads do call record_stack_base_and_size(), there is
384 // not proper way to enforce that.
385 #if INCLUDE_NMT
386 if (_stack_base != NULL) {
387 MemTracker::release_thread_stack(stack_end(), stack_size());
388 #ifdef ASSERT
389 set_stack_base(NULL);
390 #endif
391 }
392 #endif // INCLUDE_NMT
393
394 // deallocate data structures
395 delete resource_area();
396 // since the handle marks are using the handle area, we have to deallocated the root
397 // handle mark before deallocating the thread's handle area,
398 assert(last_handle_mark() != NULL, "check we have an element");
399 delete last_handle_mark();
400 assert(last_handle_mark() == NULL, "check we have reached the end");
401
402 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
403 // We NULL out the fields for good hygiene.
404 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
405 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
406 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
407 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
408
409 delete handle_area();
410 delete metadata_handles();
411
412 // SR_handler uses this as a termination indicator -
413 // needs to happen before os::free_thread()
414 delete _SR_lock;
415 _SR_lock = NULL;
416
417 // osthread() can be NULL, if creation of thread failed.
418 if (osthread() != NULL) os::free_thread(osthread());
419
420 // clear Thread::current if thread is deleting itself.
421 // Needed to ensure JNI correctly detects non-attached threads.
422 if (this == Thread::current()) {
423 clear_thread_current();
424 }
425
426 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
427 }
428
429 // NOTE: dummy function for assertion purpose.
430 void Thread::run() {
431 ShouldNotReachHere();
432 }
433
434 #ifdef ASSERT
435 // A JavaThread is considered "dangling" if it is not the current
436 // thread, has been added the Threads list, the system is not at a
437 // safepoint and the Thread is not "protected".
438 //
439 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
440 assert(!thread->is_Java_thread() || Thread::current() == thread ||
441 !((JavaThread *) thread)->on_thread_list() ||
442 SafepointSynchronize::is_at_safepoint() ||
443 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
444 "possibility of dangling Thread pointer");
445 }
446 #endif
447
448 ThreadPriority Thread::get_priority(const Thread* const thread) {
449 ThreadPriority priority;
450 // Can return an error!
451 (void)os::get_priority(thread, priority);
452 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
453 return priority;
454 }
455
456 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
457 debug_only(check_for_dangling_thread_pointer(thread);)
458 // Can return an error!
459 (void)os::set_priority(thread, priority);
460 }
461
462
463 void Thread::start(Thread* thread) {
464 // Start is different from resume in that its safety is guaranteed by context or
465 // being called from a Java method synchronized on the Thread object.
466 if (!DisableStartThread) {
467 if (thread->is_Java_thread()) {
468 // Initialize the thread state to RUNNABLE before starting this thread.
469 // Can not set it after the thread started because we do not know the
470 // exact thread state at that time. It could be in MONITOR_WAIT or
471 // in SLEEPING or some other state.
472 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
473 java_lang_Thread::RUNNABLE);
474 }
475 os::start_thread(thread);
476 }
477 }
478
479 // Enqueue a VM_Operation to do the job for us - sometime later
480 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
481 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
482 VMThread::execute(vm_stop);
483 }
484
485
486 // Check if an external suspend request has completed (or has been
487 // cancelled). Returns true if the thread is externally suspended and
488 // false otherwise.
489 //
490 // The bits parameter returns information about the code path through
491 // the routine. Useful for debugging:
492 //
493 // set in is_ext_suspend_completed():
494 // 0x00000001 - routine was entered
495 // 0x00000010 - routine return false at end
496 // 0x00000100 - thread exited (return false)
497 // 0x00000200 - suspend request cancelled (return false)
498 // 0x00000400 - thread suspended (return true)
499 // 0x00001000 - thread is in a suspend equivalent state (return true)
500 // 0x00002000 - thread is native and walkable (return true)
501 // 0x00004000 - thread is native_trans and walkable (needed retry)
502 //
503 // set in wait_for_ext_suspend_completion():
504 // 0x00010000 - routine was entered
505 // 0x00020000 - suspend request cancelled before loop (return false)
506 // 0x00040000 - thread suspended before loop (return true)
507 // 0x00080000 - suspend request cancelled in loop (return false)
508 // 0x00100000 - thread suspended in loop (return true)
509 // 0x00200000 - suspend not completed during retry loop (return false)
510
511 // Helper class for tracing suspend wait debug bits.
512 //
513 // 0x00000100 indicates that the target thread exited before it could
514 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
515 // 0x00080000 each indicate a cancelled suspend request so they don't
516 // count as wait failures either.
517 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
518
519 class TraceSuspendDebugBits : public StackObj {
520 private:
521 JavaThread * jt;
522 bool is_wait;
523 bool called_by_wait; // meaningful when !is_wait
524 uint32_t * bits;
525
526 public:
527 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
528 uint32_t *_bits) {
529 jt = _jt;
530 is_wait = _is_wait;
531 called_by_wait = _called_by_wait;
532 bits = _bits;
533 }
534
535 ~TraceSuspendDebugBits() {
536 if (!is_wait) {
537 #if 1
538 // By default, don't trace bits for is_ext_suspend_completed() calls.
539 // That trace is very chatty.
540 return;
541 #else
542 if (!called_by_wait) {
543 // If tracing for is_ext_suspend_completed() is enabled, then only
544 // trace calls to it from wait_for_ext_suspend_completion()
545 return;
546 }
547 #endif
548 }
549
550 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
551 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
552 MutexLocker ml(Threads_lock); // needed for get_thread_name()
553 ResourceMark rm;
554
555 tty->print_cr(
556 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
557 jt->get_thread_name(), *bits);
558
559 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
560 }
561 }
562 }
563 };
564 #undef DEBUG_FALSE_BITS
565
566
567 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
568 uint32_t *bits) {
569 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
570
571 bool did_trans_retry = false; // only do thread_in_native_trans retry once
572 bool do_trans_retry; // flag to force the retry
573
574 *bits |= 0x00000001;
575
576 do {
577 do_trans_retry = false;
578
579 if (is_exiting()) {
580 // Thread is in the process of exiting. This is always checked
581 // first to reduce the risk of dereferencing a freed JavaThread.
582 *bits |= 0x00000100;
583 return false;
584 }
585
586 if (!is_external_suspend()) {
587 // Suspend request is cancelled. This is always checked before
588 // is_ext_suspended() to reduce the risk of a rogue resume
589 // confusing the thread that made the suspend request.
590 *bits |= 0x00000200;
591 return false;
592 }
593
594 if (is_ext_suspended()) {
595 // thread is suspended
596 *bits |= 0x00000400;
597 return true;
598 }
599
600 // Now that we no longer do hard suspends of threads running
601 // native code, the target thread can be changing thread state
602 // while we are in this routine:
603 //
604 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
605 //
606 // We save a copy of the thread state as observed at this moment
607 // and make our decision about suspend completeness based on the
608 // copy. This closes the race where the thread state is seen as
609 // _thread_in_native_trans in the if-thread_blocked check, but is
610 // seen as _thread_blocked in if-thread_in_native_trans check.
611 JavaThreadState save_state = thread_state();
612
613 if (save_state == _thread_blocked && is_suspend_equivalent()) {
614 // If the thread's state is _thread_blocked and this blocking
615 // condition is known to be equivalent to a suspend, then we can
616 // consider the thread to be externally suspended. This means that
617 // the code that sets _thread_blocked has been modified to do
618 // self-suspension if the blocking condition releases. We also
619 // used to check for CONDVAR_WAIT here, but that is now covered by
620 // the _thread_blocked with self-suspension check.
621 //
622 // Return true since we wouldn't be here unless there was still an
623 // external suspend request.
624 *bits |= 0x00001000;
625 return true;
626 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
627 // Threads running native code will self-suspend on native==>VM/Java
628 // transitions. If its stack is walkable (should always be the case
629 // unless this function is called before the actual java_suspend()
630 // call), then the wait is done.
631 *bits |= 0x00002000;
632 return true;
633 } else if (!called_by_wait && !did_trans_retry &&
634 save_state == _thread_in_native_trans &&
635 frame_anchor()->walkable()) {
636 // The thread is transitioning from thread_in_native to another
637 // thread state. check_safepoint_and_suspend_for_native_trans()
638 // will force the thread to self-suspend. If it hasn't gotten
639 // there yet we may have caught the thread in-between the native
640 // code check above and the self-suspend. Lucky us. If we were
641 // called by wait_for_ext_suspend_completion(), then it
642 // will be doing the retries so we don't have to.
643 //
644 // Since we use the saved thread state in the if-statement above,
645 // there is a chance that the thread has already transitioned to
646 // _thread_blocked by the time we get here. In that case, we will
647 // make a single unnecessary pass through the logic below. This
648 // doesn't hurt anything since we still do the trans retry.
649
650 *bits |= 0x00004000;
651
652 // Once the thread leaves thread_in_native_trans for another
653 // thread state, we break out of this retry loop. We shouldn't
654 // need this flag to prevent us from getting back here, but
655 // sometimes paranoia is good.
656 did_trans_retry = true;
657
658 // We wait for the thread to transition to a more usable state.
659 for (int i = 1; i <= SuspendRetryCount; i++) {
660 // We used to do an "os::yield_all(i)" call here with the intention
661 // that yielding would increase on each retry. However, the parameter
662 // is ignored on Linux which means the yield didn't scale up. Waiting
663 // on the SR_lock below provides a much more predictable scale up for
664 // the delay. It also provides a simple/direct point to check for any
665 // safepoint requests from the VMThread
666
667 // temporarily drops SR_lock while doing wait with safepoint check
668 // (if we're a JavaThread - the WatcherThread can also call this)
669 // and increase delay with each retry
670 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
671
672 // check the actual thread state instead of what we saved above
673 if (thread_state() != _thread_in_native_trans) {
674 // the thread has transitioned to another thread state so
675 // try all the checks (except this one) one more time.
676 do_trans_retry = true;
677 break;
678 }
679 } // end retry loop
680
681
682 }
683 } while (do_trans_retry);
684
685 *bits |= 0x00000010;
686 return false;
687 }
688
689 // Wait for an external suspend request to complete (or be cancelled).
690 // Returns true if the thread is externally suspended and false otherwise.
691 //
692 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
693 uint32_t *bits) {
694 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
695 false /* !called_by_wait */, bits);
696
697 // local flag copies to minimize SR_lock hold time
698 bool is_suspended;
699 bool pending;
700 uint32_t reset_bits;
701
702 // set a marker so is_ext_suspend_completed() knows we are the caller
703 *bits |= 0x00010000;
704
705 // We use reset_bits to reinitialize the bits value at the top of
706 // each retry loop. This allows the caller to make use of any
707 // unused bits for their own marking purposes.
708 reset_bits = *bits;
709
710 {
711 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
712 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
713 delay, bits);
714 pending = is_external_suspend();
715 }
716 // must release SR_lock to allow suspension to complete
717
718 if (!pending) {
719 // A cancelled suspend request is the only false return from
720 // is_ext_suspend_completed() that keeps us from entering the
721 // retry loop.
722 *bits |= 0x00020000;
723 return false;
724 }
725
726 if (is_suspended) {
727 *bits |= 0x00040000;
728 return true;
729 }
730
731 for (int i = 1; i <= retries; i++) {
732 *bits = reset_bits; // reinit to only track last retry
733
734 // We used to do an "os::yield_all(i)" call here with the intention
735 // that yielding would increase on each retry. However, the parameter
736 // is ignored on Linux which means the yield didn't scale up. Waiting
737 // on the SR_lock below provides a much more predictable scale up for
738 // the delay. It also provides a simple/direct point to check for any
739 // safepoint requests from the VMThread
740
741 {
742 MutexLocker ml(SR_lock());
743 // wait with safepoint check (if we're a JavaThread - the WatcherThread
744 // can also call this) and increase delay with each retry
745 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
746
747 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
748 delay, bits);
749
750 // It is possible for the external suspend request to be cancelled
751 // (by a resume) before the actual suspend operation is completed.
752 // Refresh our local copy to see if we still need to wait.
753 pending = is_external_suspend();
754 }
755
756 if (!pending) {
757 // A cancelled suspend request is the only false return from
758 // is_ext_suspend_completed() that keeps us from staying in the
759 // retry loop.
760 *bits |= 0x00080000;
761 return false;
762 }
763
764 if (is_suspended) {
765 *bits |= 0x00100000;
766 return true;
767 }
768 } // end retry loop
769
770 // thread did not suspend after all our retries
771 *bits |= 0x00200000;
772 return false;
773 }
774
775 // Called from API entry points which perform stack walking. If the
776 // associated JavaThread is the current thread, then wait_for_suspend
777 // is not used. Otherwise, it determines if we should wait for the
778 // "other" thread to complete external suspension. (NOTE: in future
779 // releases the suspension mechanism should be reimplemented so this
780 // is not necessary.)
781 //
782 bool
783 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
784 if (this != JavaThread::current()) {
785 // "other" threads require special handling.
786 if (wait_for_suspend) {
787 // We are allowed to wait for the external suspend to complete
788 // so give the other thread a chance to get suspended.
789 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
790 SuspendRetryDelay, bits)) {
791 // Didn't make it so let the caller know.
792 return false;
793 }
794 }
795 // We aren't allowed to wait for the external suspend to complete
796 // so if the other thread isn't externally suspended we need to
797 // let the caller know.
798 else if (!is_ext_suspend_completed_with_lock(bits)) {
799 return false;
800 }
801 }
802
803 return true;
804 }
805
806 #ifndef PRODUCT
807 void JavaThread::record_jump(address target, address instr, const char* file,
808 int line) {
809
810 // This should not need to be atomic as the only way for simultaneous
811 // updates is via interrupts. Even then this should be rare or non-existent
812 // and we don't care that much anyway.
813
814 int index = _jmp_ring_index;
815 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
816 _jmp_ring[index]._target = (intptr_t) target;
817 _jmp_ring[index]._instruction = (intptr_t) instr;
818 _jmp_ring[index]._file = file;
819 _jmp_ring[index]._line = line;
820 }
821 #endif // PRODUCT
822
823 void Thread::interrupt(Thread* thread) {
824 debug_only(check_for_dangling_thread_pointer(thread);)
825 os::interrupt(thread);
826 }
827
828 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
829 debug_only(check_for_dangling_thread_pointer(thread);)
830 // Note: If clear_interrupted==false, this simply fetches and
831 // returns the value of the field osthread()->interrupted().
832 return os::is_interrupted(thread, clear_interrupted);
833 }
834
835
836 // GC Support
837 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
838 int thread_parity = _oops_do_parity;
839 if (thread_parity != strong_roots_parity) {
840 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
841 if (res == thread_parity) {
842 return true;
843 } else {
844 guarantee(res == strong_roots_parity, "Or else what?");
845 return false;
846 }
847 }
848 return false;
849 }
850
851 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
852 active_handles()->oops_do(f);
853 // Do oop for ThreadShadow
854 f->do_oop((oop*)&_pending_exception);
855 handle_area()->oops_do(f);
856
857 if (MonitorInUseLists) {
858 // When using thread local monitor lists, we scan them here,
859 // and the remaining global monitors in ObjectSynchronizer::oops_do().
860 ObjectSynchronizer::thread_local_used_oops_do(this, f);
861 }
862 }
863
864 void Thread::metadata_handles_do(void f(Metadata*)) {
865 // Only walk the Handles in Thread.
866 if (metadata_handles() != NULL) {
867 for (int i = 0; i< metadata_handles()->length(); i++) {
868 f(metadata_handles()->at(i));
869 }
870 }
871 }
872
873 void Thread::print_on(outputStream* st, bool print_extended_info) const {
874 // get_priority assumes osthread initialized
875 if (osthread() != NULL) {
876 int os_prio;
877 if (os::get_native_priority(this, &os_prio) == OS_OK) {
878 st->print("os_prio=%d ", os_prio);
879 }
880
881 st->print("cpu=%.2fms ",
882 os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
883 );
884 st->print("elapsed=%.2fs ",
885 _statistical_info.getElapsedTime() / 1000.0
886 );
887 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
888 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
889 st->print("allocated=" SIZE_FORMAT "%s ",
890 byte_size_in_proper_unit(allocated_bytes),
891 proper_unit_for_byte_size(allocated_bytes)
892 );
893 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
894 }
895
896 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
897 osthread()->print_on(st);
898 }
899 ThreadsSMRSupport::print_info_on(this, st);
900 st->print(" ");
901 debug_only(if (WizardMode) print_owned_locks_on(st);)
902 }
903
904 // Thread::print_on_error() is called by fatal error handler. Don't use
905 // any lock or allocate memory.
906 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
907 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
908
909 if (is_VM_thread()) { st->print("VMThread"); }
910 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
911 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
912 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
913 else { st->print("Thread"); }
914
915 if (is_Named_thread()) {
916 st->print(" \"%s\"", name());
917 }
918
919 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
920 p2i(stack_end()), p2i(stack_base()));
921
922 if (osthread()) {
923 st->print(" [id=%d]", osthread()->thread_id());
924 }
925
926 ThreadsSMRSupport::print_info_on(this, st);
927 }
928
929 void Thread::print_value_on(outputStream* st) const {
930 if (is_Named_thread()) {
931 st->print(" \"%s\" ", name());
932 }
933 st->print(INTPTR_FORMAT, p2i(this)); // print address
934 }
935
936 #ifdef ASSERT
937 void Thread::print_owned_locks_on(outputStream* st) const {
938 Monitor *cur = _owned_locks;
939 if (cur == NULL) {
940 st->print(" (no locks) ");
941 } else {
942 st->print_cr(" Locks owned:");
943 while (cur) {
944 cur->print_on(st);
945 cur = cur->next();
946 }
947 }
948 }
949
950 static int ref_use_count = 0;
951
952 bool Thread::owns_locks_but_compiled_lock() const {
953 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
954 if (cur != Compile_lock) return true;
955 }
956 return false;
957 }
958
959
960 #endif
961
962 #ifndef PRODUCT
963
964 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially
965 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that
966 // no threads which allow_vm_block's are held
967 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
968 // Check if current thread is allowed to block at a safepoint
969 if (!(_allow_safepoint_count == 0)) {
970 fatal("Possible safepoint reached by thread that does not allow it");
971 }
972 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
973 fatal("LEAF method calling lock?");
974 }
975
976 #ifdef ASSERT
977 if (potential_vm_operation && is_Java_thread()
978 && !Universe::is_bootstrapping()) {
979 // Make sure we do not hold any locks that the VM thread also uses.
980 // This could potentially lead to deadlocks
981 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
982 // Threads_lock is special, since the safepoint synchronization will not start before this is
983 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
984 // since it is used to transfer control between JavaThreads and the VMThread
985 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
986 if ((cur->allow_vm_block() &&
987 cur != Threads_lock &&
988 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
989 cur != VMOperationRequest_lock &&
990 cur != VMOperationQueue_lock) ||
991 cur->rank() == Mutex::special) {
992 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
993 }
994 }
995 }
996
997 if (GCALotAtAllSafepoints) {
998 // We could enter a safepoint here and thus have a gc
999 InterfaceSupport::check_gc_alot();
1000 }
1001 #endif
1002 }
1003 #endif
1004
1005 bool Thread::is_in_stack(address adr) const {
1006 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
1007 address end = os::current_stack_pointer();
1008 // Allow non Java threads to call this without stack_base
1009 if (_stack_base == NULL) return true;
1010 if (stack_base() >= adr && adr >= end) return true;
1011
1012 return false;
1013 }
1014
1015 bool Thread::is_in_usable_stack(address adr) const {
1016 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1017 size_t usable_stack_size = _stack_size - stack_guard_size;
1018
1019 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1020 }
1021
1022
1023 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1024 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1025 // used for compilation in the future. If that change is made, the need for these methods
1026 // should be revisited, and they should be removed if possible.
1027
1028 bool Thread::is_lock_owned(address adr) const {
1029 return on_local_stack(adr);
1030 }
1031
1032 bool Thread::set_as_starting_thread() {
1033 // NOTE: this must be called inside the main thread.
1034 return os::create_main_thread((JavaThread*)this);
1035 }
1036
1037 static void initialize_class(Symbol* class_name, TRAPS) {
1038 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1039 InstanceKlass::cast(klass)->initialize(CHECK);
1040 }
1041
1042
1043 // Creates the initial ThreadGroup
1044 static Handle create_initial_thread_group(TRAPS) {
1045 Handle system_instance = JavaCalls::construct_new_instance(
1046 SystemDictionary::ThreadGroup_klass(),
1047 vmSymbols::void_method_signature(),
1048 CHECK_NH);
1049 Universe::set_system_thread_group(system_instance());
1050
1051 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1052 Handle main_instance = JavaCalls::construct_new_instance(
1053 SystemDictionary::ThreadGroup_klass(),
1054 vmSymbols::threadgroup_string_void_signature(),
1055 system_instance,
1056 string,
1057 CHECK_NH);
1058 return main_instance;
1059 }
1060
1061 // Creates the initial Thread
1062 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1063 TRAPS) {
1064 InstanceKlass* ik = SystemDictionary::Thread_klass();
1065 assert(ik->is_initialized(), "must be");
1066 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1067
1068 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1069 // constructor calls Thread.current(), which must be set here for the
1070 // initial thread.
1071 java_lang_Thread::set_thread(thread_oop(), thread);
1072 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1073 thread->set_threadObj(thread_oop());
1074
1075 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1076
1077 JavaValue result(T_VOID);
1078 JavaCalls::call_special(&result, thread_oop,
1079 ik,
1080 vmSymbols::object_initializer_name(),
1081 vmSymbols::threadgroup_string_void_signature(),
1082 thread_group,
1083 string,
1084 CHECK_NULL);
1085 return thread_oop();
1086 }
1087
1088 char java_runtime_name[128] = "";
1089 char java_runtime_version[128] = "";
1090
1091 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1092 static const char* get_java_runtime_name(TRAPS) {
1093 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1094 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1095 fieldDescriptor fd;
1096 bool found = k != NULL &&
1097 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1098 vmSymbols::string_signature(), &fd);
1099 if (found) {
1100 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1101 if (name_oop == NULL) {
1102 return NULL;
1103 }
1104 const char* name = java_lang_String::as_utf8_string(name_oop,
1105 java_runtime_name,
1106 sizeof(java_runtime_name));
1107 return name;
1108 } else {
1109 return NULL;
1110 }
1111 }
1112
1113 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1114 static const char* get_java_runtime_version(TRAPS) {
1115 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1116 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1117 fieldDescriptor fd;
1118 bool found = k != NULL &&
1119 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1120 vmSymbols::string_signature(), &fd);
1121 if (found) {
1122 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1123 if (name_oop == NULL) {
1124 return NULL;
1125 }
1126 const char* name = java_lang_String::as_utf8_string(name_oop,
1127 java_runtime_version,
1128 sizeof(java_runtime_version));
1129 return name;
1130 } else {
1131 return NULL;
1132 }
1133 }
1134
1135 // General purpose hook into Java code, run once when the VM is initialized.
1136 // The Java library method itself may be changed independently from the VM.
1137 static void call_postVMInitHook(TRAPS) {
1138 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1139 if (klass != NULL) {
1140 JavaValue result(T_VOID);
1141 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1142 vmSymbols::void_method_signature(),
1143 CHECK);
1144 }
1145 }
1146
1147 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1148 bool daemon, TRAPS) {
1149 assert(thread_group.not_null(), "thread group should be specified");
1150 assert(threadObj() == NULL, "should only create Java thread object once");
1151
1152 InstanceKlass* ik = SystemDictionary::Thread_klass();
1153 assert(ik->is_initialized(), "must be");
1154 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1155
1156 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
1157 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
1158 // constructor calls Thread.current(), which must be set here.
1159 java_lang_Thread::set_thread(thread_oop(), this);
1160 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1161 set_threadObj(thread_oop());
1162
1163 JavaValue result(T_VOID);
1164 if (thread_name != NULL) {
1165 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1166 // Thread gets assigned specified name and null target
1167 JavaCalls::call_special(&result,
1168 thread_oop,
1169 ik,
1170 vmSymbols::object_initializer_name(),
1171 vmSymbols::threadgroup_string_void_signature(),
1172 thread_group,
1173 name,
1174 THREAD);
1175 } else {
1176 // Thread gets assigned name "Thread-nnn" and null target
1177 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1178 JavaCalls::call_special(&result,
1179 thread_oop,
1180 ik,
1181 vmSymbols::object_initializer_name(),
1182 vmSymbols::threadgroup_runnable_void_signature(),
1183 thread_group,
1184 Handle(),
1185 THREAD);
1186 }
1187
1188
1189 if (daemon) {
1190 java_lang_Thread::set_daemon(thread_oop());
1191 }
1192
1193 if (HAS_PENDING_EXCEPTION) {
1194 return;
1195 }
1196
1197 Klass* group = SystemDictionary::ThreadGroup_klass();
1198 Handle threadObj(THREAD, this->threadObj());
1199
1200 JavaCalls::call_special(&result,
1201 thread_group,
1202 group,
1203 vmSymbols::add_method_name(),
1204 vmSymbols::thread_void_signature(),
1205 threadObj, // Arg 1
1206 THREAD);
1207 }
1208
1209 // NamedThread -- non-JavaThread subclasses with multiple
1210 // uniquely named instances should derive from this.
1211 NamedThread::NamedThread() : Thread() {
1212 _name = NULL;
1213 _processed_thread = NULL;
1214 _gc_id = GCId::undefined();
1215 }
1216
1217 NamedThread::~NamedThread() {
1218 if (_name != NULL) {
1219 FREE_C_HEAP_ARRAY(char, _name);
1220 _name = NULL;
1221 }
1222 }
1223
1224 void NamedThread::set_name(const char* format, ...) {
1225 guarantee(_name == NULL, "Only get to set name once.");
1226 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1227 guarantee(_name != NULL, "alloc failure");
1228 va_list ap;
1229 va_start(ap, format);
1230 jio_vsnprintf(_name, max_name_len, format, ap);
1231 va_end(ap);
1232 }
1233
1234 void NamedThread::initialize_named_thread() {
1235 set_native_thread_name(name());
1236 }
1237
1238 void NamedThread::print_on(outputStream* st) const {
1239 st->print("\"%s\" ", name());
1240 Thread::print_on(st);
1241 st->cr();
1242 }
1243
1244
1245 // ======= WatcherThread ========
1246
1247 // The watcher thread exists to simulate timer interrupts. It should
1248 // be replaced by an abstraction over whatever native support for
1249 // timer interrupts exists on the platform.
1250
1251 WatcherThread* WatcherThread::_watcher_thread = NULL;
1252 bool WatcherThread::_startable = false;
1253 volatile bool WatcherThread::_should_terminate = false;
1254
1255 WatcherThread::WatcherThread() : Thread() {
1256 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1257 if (os::create_thread(this, os::watcher_thread)) {
1258 _watcher_thread = this;
1259
1260 // Set the watcher thread to the highest OS priority which should not be
1261 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1262 // is created. The only normal thread using this priority is the reference
1263 // handler thread, which runs for very short intervals only.
1264 // If the VMThread's priority is not lower than the WatcherThread profiling
1265 // will be inaccurate.
1266 os::set_priority(this, MaxPriority);
1267 if (!DisableStartThread) {
1268 os::start_thread(this);
1269 }
1270 }
1271 }
1272
1273 int WatcherThread::sleep() const {
1274 // The WatcherThread does not participate in the safepoint protocol
1275 // for the PeriodicTask_lock because it is not a JavaThread.
1276 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1277
1278 if (_should_terminate) {
1279 // check for termination before we do any housekeeping or wait
1280 return 0; // we did not sleep.
1281 }
1282
1283 // remaining will be zero if there are no tasks,
1284 // causing the WatcherThread to sleep until a task is
1285 // enrolled
1286 int remaining = PeriodicTask::time_to_wait();
1287 int time_slept = 0;
1288
1289 // we expect this to timeout - we only ever get unparked when
1290 // we should terminate or when a new task has been enrolled
1291 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1292
1293 jlong time_before_loop = os::javaTimeNanos();
1294
1295 while (true) {
1296 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1297 remaining);
1298 jlong now = os::javaTimeNanos();
1299
1300 if (remaining == 0) {
1301 // if we didn't have any tasks we could have waited for a long time
1302 // consider the time_slept zero and reset time_before_loop
1303 time_slept = 0;
1304 time_before_loop = now;
1305 } else {
1306 // need to recalculate since we might have new tasks in _tasks
1307 time_slept = (int) ((now - time_before_loop) / 1000000);
1308 }
1309
1310 // Change to task list or spurious wakeup of some kind
1311 if (timedout || _should_terminate) {
1312 break;
1313 }
1314
1315 remaining = PeriodicTask::time_to_wait();
1316 if (remaining == 0) {
1317 // Last task was just disenrolled so loop around and wait until
1318 // another task gets enrolled
1319 continue;
1320 }
1321
1322 remaining -= time_slept;
1323 if (remaining <= 0) {
1324 break;
1325 }
1326 }
1327
1328 return time_slept;
1329 }
1330
1331 void WatcherThread::run() {
1332 assert(this == watcher_thread(), "just checking");
1333
1334 this->record_stack_base_and_size();
1335 this->set_native_thread_name(this->name());
1336 this->set_active_handles(JNIHandleBlock::allocate_block());
1337 while (true) {
1338 assert(watcher_thread() == Thread::current(), "thread consistency check");
1339 assert(watcher_thread() == this, "thread consistency check");
1340
1341 // Calculate how long it'll be until the next PeriodicTask work
1342 // should be done, and sleep that amount of time.
1343 int time_waited = sleep();
1344
1345 if (VMError::is_error_reported()) {
1346 // A fatal error has happened, the error handler(VMError::report_and_die)
1347 // should abort JVM after creating an error log file. However in some
1348 // rare cases, the error handler itself might deadlock. Here periodically
1349 // check for error reporting timeouts, and if it happens, just proceed to
1350 // abort the VM.
1351
1352 // This code is in WatcherThread because WatcherThread wakes up
1353 // periodically so the fatal error handler doesn't need to do anything;
1354 // also because the WatcherThread is less likely to crash than other
1355 // threads.
1356
1357 for (;;) {
1358 // Note: we use naked sleep in this loop because we want to avoid using
1359 // any kind of VM infrastructure which may be broken at this point.
1360 if (VMError::check_timeout()) {
1361 // We hit error reporting timeout. Error reporting was interrupted and
1362 // will be wrapping things up now (closing files etc). Give it some more
1363 // time, then quit the VM.
1364 os::naked_short_sleep(200);
1365 // Print a message to stderr.
1366 fdStream err(defaultStream::output_fd());
1367 err.print_raw_cr("# [ timer expired, abort... ]");
1368 // skip atexit/vm_exit/vm_abort hooks
1369 os::die();
1370 }
1371
1372 // Wait a second, then recheck for timeout.
1373 os::naked_short_sleep(999);
1374 }
1375 }
1376
1377 if (_should_terminate) {
1378 // check for termination before posting the next tick
1379 break;
1380 }
1381
1382 PeriodicTask::real_time_tick(time_waited);
1383 }
1384
1385 // Signal that it is terminated
1386 {
1387 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1388 _watcher_thread = NULL;
1389 Terminator_lock->notify();
1390 }
1391 }
1392
1393 void WatcherThread::start() {
1394 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1395
1396 if (watcher_thread() == NULL && _startable) {
1397 _should_terminate = false;
1398 // Create the single instance of WatcherThread
1399 new WatcherThread();
1400 }
1401 }
1402
1403 void WatcherThread::make_startable() {
1404 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1405 _startable = true;
1406 }
1407
1408 void WatcherThread::stop() {
1409 {
1410 // Follow normal safepoint aware lock enter protocol since the
1411 // WatcherThread is stopped by another JavaThread.
1412 MutexLocker ml(PeriodicTask_lock);
1413 _should_terminate = true;
1414
1415 WatcherThread* watcher = watcher_thread();
1416 if (watcher != NULL) {
1417 // unpark the WatcherThread so it can see that it should terminate
1418 watcher->unpark();
1419 }
1420 }
1421
1422 MutexLocker mu(Terminator_lock);
1423
1424 while (watcher_thread() != NULL) {
1425 // This wait should make safepoint checks, wait without a timeout,
1426 // and wait as a suspend-equivalent condition.
1427 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1428 Mutex::_as_suspend_equivalent_flag);
1429 }
1430 }
1431
1432 void WatcherThread::unpark() {
1433 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1434 PeriodicTask_lock->notify();
1435 }
1436
1437 void WatcherThread::print_on(outputStream* st) const {
1438 st->print("\"%s\" ", name());
1439 Thread::print_on(st);
1440 st->cr();
1441 }
1442
1443 // ======= JavaThread ========
1444
1445 #if INCLUDE_JVMCI
1446
1447 jlong* JavaThread::_jvmci_old_thread_counters;
1448
1449 bool jvmci_counters_include(JavaThread* thread) {
1450 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1451 }
1452
1453 void JavaThread::collect_counters(typeArrayOop array) {
1454 if (JVMCICounterSize > 0) {
1455 JavaThreadIteratorWithHandle jtiwh;
1456 for (int i = 0; i < array->length(); i++) {
1457 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1458 }
1459 for (; JavaThread *tp = jtiwh.next(); ) {
1460 if (jvmci_counters_include(tp)) {
1461 for (int i = 0; i < array->length(); i++) {
1462 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1463 }
1464 }
1465 }
1466 }
1467 }
1468
1469 #endif // INCLUDE_JVMCI
1470
1471 // A JavaThread is a normal Java thread
1472
1473 void JavaThread::initialize() {
1474 // Initialize fields
1475
1476 set_saved_exception_pc(NULL);
1477 set_threadObj(NULL);
1478 _anchor.clear();
1479 set_entry_point(NULL);
1480 set_jni_functions(jni_functions());
1481 set_callee_target(NULL);
1482 set_vm_result(NULL);
1483 set_vm_result_2(NULL);
1484 set_vframe_array_head(NULL);
1485 set_vframe_array_last(NULL);
1486 set_deferred_locals(NULL);
1487 set_deopt_mark(NULL);
1488 set_deopt_compiled_method(NULL);
1489 clear_must_deopt_id();
1490 set_monitor_chunks(NULL);
1491 set_next(NULL);
1492 _on_thread_list = false;
1493 set_thread_state(_thread_new);
1494 _terminated = _not_terminated;
1495 _privileged_stack_top = NULL;
1496 _array_for_gc = NULL;
1497 _suspend_equivalent = false;
1498 _in_deopt_handler = 0;
1499 _doing_unsafe_access = false;
1500 _stack_guard_state = stack_guard_unused;
1501 #if INCLUDE_JVMCI
1502 _pending_monitorenter = false;
1503 _pending_deoptimization = -1;
1504 _pending_failed_speculation = NULL;
1505 _pending_transfer_to_interpreter = false;
1506 _adjusting_comp_level = false;
1507 _jvmci._alternate_call_target = NULL;
1508 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1509 if (JVMCICounterSize > 0) {
1510 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1511 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1512 } else {
1513 _jvmci_counters = NULL;
1514 }
1515 #endif // INCLUDE_JVMCI
1516 _reserved_stack_activation = NULL; // stack base not known yet
1517 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1518 _exception_pc = 0;
1519 _exception_handler_pc = 0;
1520 _is_method_handle_return = 0;
1521 _jvmti_thread_state= NULL;
1522 _should_post_on_exceptions_flag = JNI_FALSE;
1523 _jvmti_get_loaded_classes_closure = NULL;
1524 _interp_only_mode = 0;
1525 _special_runtime_exit_condition = _no_async_condition;
1526 _pending_async_exception = NULL;
1527 _thread_stat = NULL;
1528 _thread_stat = new ThreadStatistics();
1529 _blocked_on_compilation = false;
1530 _jni_active_critical = 0;
1531 _pending_jni_exception_check_fn = NULL;
1532 _do_not_unlock_if_synchronized = false;
1533 _cached_monitor_info = NULL;
1534 _parker = Parker::Allocate(this);
1535
1536 #ifndef PRODUCT
1537 _jmp_ring_index = 0;
1538 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1539 record_jump(NULL, NULL, NULL, 0);
1540 }
1541 #endif // PRODUCT
1542
1543 // Setup safepoint state info for this thread
1544 ThreadSafepointState::create(this);
1545
1546 debug_only(_java_call_counter = 0);
1547
1548 // JVMTI PopFrame support
1549 _popframe_condition = popframe_inactive;
1550 _popframe_preserved_args = NULL;
1551 _popframe_preserved_args_size = 0;
1552 _frames_to_pop_failed_realloc = 0;
1553
1554 if (SafepointMechanism::uses_thread_local_poll()) {
1555 SafepointMechanism::initialize_header(this);
1556 }
1557
1558 pd_initialize();
1559 }
1560
1561 JavaThread::JavaThread(bool is_attaching_via_jni) :
1562 Thread() {
1563 initialize();
1564 if (is_attaching_via_jni) {
1565 _jni_attach_state = _attaching_via_jni;
1566 } else {
1567 _jni_attach_state = _not_attaching_via_jni;
1568 }
1569 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1570 }
1571
1572 bool JavaThread::reguard_stack(address cur_sp) {
1573 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1574 && _stack_guard_state != stack_guard_reserved_disabled) {
1575 return true; // Stack already guarded or guard pages not needed.
1576 }
1577
1578 if (register_stack_overflow()) {
1579 // For those architectures which have separate register and
1580 // memory stacks, we must check the register stack to see if
1581 // it has overflowed.
1582 return false;
1583 }
1584
1585 // Java code never executes within the yellow zone: the latter is only
1586 // there to provoke an exception during stack banging. If java code
1587 // is executing there, either StackShadowPages should be larger, or
1588 // some exception code in c1, c2 or the interpreter isn't unwinding
1589 // when it should.
1590 guarantee(cur_sp > stack_reserved_zone_base(),
1591 "not enough space to reguard - increase StackShadowPages");
1592 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1593 enable_stack_yellow_reserved_zone();
1594 if (reserved_stack_activation() != stack_base()) {
1595 set_reserved_stack_activation(stack_base());
1596 }
1597 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1598 set_reserved_stack_activation(stack_base());
1599 enable_stack_reserved_zone();
1600 }
1601 return true;
1602 }
1603
1604 bool JavaThread::reguard_stack(void) {
1605 return reguard_stack(os::current_stack_pointer());
1606 }
1607
1608
1609 void JavaThread::block_if_vm_exited() {
1610 if (_terminated == _vm_exited) {
1611 // _vm_exited is set at safepoint, and Threads_lock is never released
1612 // we will block here forever
1613 Threads_lock->lock_without_safepoint_check();
1614 ShouldNotReachHere();
1615 }
1616 }
1617
1618
1619 // Remove this ifdef when C1 is ported to the compiler interface.
1620 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1621 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1622
1623 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1624 Thread() {
1625 initialize();
1626 _jni_attach_state = _not_attaching_via_jni;
1627 set_entry_point(entry_point);
1628 // Create the native thread itself.
1629 // %note runtime_23
1630 os::ThreadType thr_type = os::java_thread;
1631 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1632 os::java_thread;
1633 os::create_thread(this, thr_type, stack_sz);
1634 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1635 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1636 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1637 // the exception consists of creating the exception object & initializing it, initialization
1638 // will leave the VM via a JavaCall and then all locks must be unlocked).
1639 //
1640 // The thread is still suspended when we reach here. Thread must be explicit started
1641 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1642 // by calling Threads:add. The reason why this is not done here, is because the thread
1643 // object must be fully initialized (take a look at JVM_Start)
1644 }
1645
1646 JavaThread::~JavaThread() {
1647
1648 // JSR166 -- return the parker to the free list
1649 Parker::Release(_parker);
1650 _parker = NULL;
1651
1652 // Free any remaining previous UnrollBlock
1653 vframeArray* old_array = vframe_array_last();
1654
1655 if (old_array != NULL) {
1656 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1657 old_array->set_unroll_block(NULL);
1658 delete old_info;
1659 delete old_array;
1660 }
1661
1662 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1663 if (deferred != NULL) {
1664 // This can only happen if thread is destroyed before deoptimization occurs.
1665 assert(deferred->length() != 0, "empty array!");
1666 do {
1667 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1668 deferred->remove_at(0);
1669 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1670 delete dlv;
1671 } while (deferred->length() != 0);
1672 delete deferred;
1673 }
1674
1675 // All Java related clean up happens in exit
1676 ThreadSafepointState::destroy(this);
1677 if (_thread_stat != NULL) delete _thread_stat;
1678
1679 #if INCLUDE_JVMCI
1680 if (JVMCICounterSize > 0) {
1681 if (jvmci_counters_include(this)) {
1682 for (int i = 0; i < JVMCICounterSize; i++) {
1683 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1684 }
1685 }
1686 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1687 }
1688 #endif // INCLUDE_JVMCI
1689 }
1690
1691
1692 // The first routine called by a new Java thread
1693 void JavaThread::run() {
1694 // initialize thread-local alloc buffer related fields
1695 this->initialize_tlab();
1696
1697 // used to test validity of stack trace backs
1698 this->record_base_of_stack_pointer();
1699
1700 // Record real stack base and size.
1701 this->record_stack_base_and_size();
1702
1703 this->create_stack_guard_pages();
1704
1705 this->cache_global_variables();
1706
1707 // Thread is now sufficient initialized to be handled by the safepoint code as being
1708 // in the VM. Change thread state from _thread_new to _thread_in_vm
1709 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1710
1711 assert(JavaThread::current() == this, "sanity check");
1712 assert(!Thread::current()->owns_locks(), "sanity check");
1713
1714 DTRACE_THREAD_PROBE(start, this);
1715
1716 // This operation might block. We call that after all safepoint checks for a new thread has
1717 // been completed.
1718 this->set_active_handles(JNIHandleBlock::allocate_block());
1719
1720 if (JvmtiExport::should_post_thread_life()) {
1721 JvmtiExport::post_thread_start(this);
1722 }
1723
1724 EventThreadStart event;
1725 if (event.should_commit()) {
1726 event.set_thread(JFR_THREAD_ID(this));
1727 event.commit();
1728 }
1729
1730 // We call another function to do the rest so we are sure that the stack addresses used
1731 // from there will be lower than the stack base just computed
1732 thread_main_inner();
1733
1734 // Note, thread is no longer valid at this point!
1735 }
1736
1737
1738 void JavaThread::thread_main_inner() {
1739 assert(JavaThread::current() == this, "sanity check");
1740 assert(this->threadObj() != NULL, "just checking");
1741
1742 // Execute thread entry point unless this thread has a pending exception
1743 // or has been stopped before starting.
1744 // Note: Due to JVM_StopThread we can have pending exceptions already!
1745 if (!this->has_pending_exception() &&
1746 !java_lang_Thread::is_stillborn(this->threadObj())) {
1747 {
1748 ResourceMark rm(this);
1749 this->set_native_thread_name(this->get_thread_name());
1750 }
1751 HandleMark hm(this);
1752 this->entry_point()(this, this);
1753 }
1754
1755 DTRACE_THREAD_PROBE(stop, this);
1756
1757 this->exit(false);
1758 this->smr_delete();
1759 }
1760
1761
1762 static void ensure_join(JavaThread* thread) {
1763 // We do not need to grab the Threads_lock, since we are operating on ourself.
1764 Handle threadObj(thread, thread->threadObj());
1765 assert(threadObj.not_null(), "java thread object must exist");
1766 ObjectLocker lock(threadObj, thread);
1767 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1768 thread->clear_pending_exception();
1769 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1770 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1771 // Clear the native thread instance - this makes isAlive return false and allows the join()
1772 // to complete once we've done the notify_all below
1773 java_lang_Thread::set_thread(threadObj(), NULL);
1774 lock.notify_all(thread);
1775 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1776 thread->clear_pending_exception();
1777 }
1778
1779
1780 // For any new cleanup additions, please check to see if they need to be applied to
1781 // cleanup_failed_attach_current_thread as well.
1782 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1783 assert(this == JavaThread::current(), "thread consistency check");
1784
1785 elapsedTimer _timer_exit_phase1;
1786 elapsedTimer _timer_exit_phase2;
1787 elapsedTimer _timer_exit_phase3;
1788 elapsedTimer _timer_exit_phase4;
1789
1790 if (log_is_enabled(Debug, os, thread, timer)) {
1791 _timer_exit_phase1.start();
1792 }
1793
1794 HandleMark hm(this);
1795 Handle uncaught_exception(this, this->pending_exception());
1796 this->clear_pending_exception();
1797 Handle threadObj(this, this->threadObj());
1798 assert(threadObj.not_null(), "Java thread object should be created");
1799
1800 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1801 {
1802 EXCEPTION_MARK;
1803
1804 CLEAR_PENDING_EXCEPTION;
1805 }
1806 if (!destroy_vm) {
1807 if (uncaught_exception.not_null()) {
1808 EXCEPTION_MARK;
1809 // Call method Thread.dispatchUncaughtException().
1810 Klass* thread_klass = SystemDictionary::Thread_klass();
1811 JavaValue result(T_VOID);
1812 JavaCalls::call_virtual(&result,
1813 threadObj, thread_klass,
1814 vmSymbols::dispatchUncaughtException_name(),
1815 vmSymbols::throwable_void_signature(),
1816 uncaught_exception,
1817 THREAD);
1818 if (HAS_PENDING_EXCEPTION) {
1819 ResourceMark rm(this);
1820 jio_fprintf(defaultStream::error_stream(),
1821 "\nException: %s thrown from the UncaughtExceptionHandler"
1822 " in thread \"%s\"\n",
1823 pending_exception()->klass()->external_name(),
1824 get_thread_name());
1825 CLEAR_PENDING_EXCEPTION;
1826 }
1827 }
1828
1829 // Called before the java thread exit since we want to read info
1830 // from java_lang_Thread object
1831 EventThreadEnd event;
1832 if (event.should_commit()) {
1833 event.set_thread(JFR_THREAD_ID(this));
1834 event.commit();
1835 }
1836
1837 // Call after last event on thread
1838 JFR_ONLY(Jfr::on_thread_exit(this);)
1839
1840 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1841 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1842 // is deprecated anyhow.
1843 if (!is_Compiler_thread()) {
1844 int count = 3;
1845 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1846 EXCEPTION_MARK;
1847 JavaValue result(T_VOID);
1848 Klass* thread_klass = SystemDictionary::Thread_klass();
1849 JavaCalls::call_virtual(&result,
1850 threadObj, thread_klass,
1851 vmSymbols::exit_method_name(),
1852 vmSymbols::void_method_signature(),
1853 THREAD);
1854 CLEAR_PENDING_EXCEPTION;
1855 }
1856 }
1857 // notify JVMTI
1858 if (JvmtiExport::should_post_thread_life()) {
1859 JvmtiExport::post_thread_end(this);
1860 }
1861
1862 // We have notified the agents that we are exiting, before we go on,
1863 // we must check for a pending external suspend request and honor it
1864 // in order to not surprise the thread that made the suspend request.
1865 while (true) {
1866 {
1867 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1868 if (!is_external_suspend()) {
1869 set_terminated(_thread_exiting);
1870 ThreadService::current_thread_exiting(this);
1871 break;
1872 }
1873 // Implied else:
1874 // Things get a little tricky here. We have a pending external
1875 // suspend request, but we are holding the SR_lock so we
1876 // can't just self-suspend. So we temporarily drop the lock
1877 // and then self-suspend.
1878 }
1879
1880 ThreadBlockInVM tbivm(this);
1881 java_suspend_self();
1882
1883 // We're done with this suspend request, but we have to loop around
1884 // and check again. Eventually we will get SR_lock without a pending
1885 // external suspend request and will be able to mark ourselves as
1886 // exiting.
1887 }
1888 // no more external suspends are allowed at this point
1889 } else {
1890 // before_exit() has already posted JVMTI THREAD_END events
1891 }
1892
1893 if (log_is_enabled(Debug, os, thread, timer)) {
1894 _timer_exit_phase1.stop();
1895 _timer_exit_phase2.start();
1896 }
1897 // Notify waiters on thread object. This has to be done after exit() is called
1898 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1899 // group should have the destroyed bit set before waiters are notified).
1900 ensure_join(this);
1901 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1902
1903 if (log_is_enabled(Debug, os, thread, timer)) {
1904 _timer_exit_phase2.stop();
1905 _timer_exit_phase3.start();
1906 }
1907 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1908 // held by this thread must be released. The spec does not distinguish
1909 // between JNI-acquired and regular Java monitors. We can only see
1910 // regular Java monitors here if monitor enter-exit matching is broken.
1911 //
1912 // Optionally release any monitors for regular JavaThread exits. This
1913 // is provided as a work around for any bugs in monitor enter-exit
1914 // matching. This can be expensive so it is not enabled by default.
1915 //
1916 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1917 // ObjectSynchronizer::release_monitors_owned_by_thread().
1918 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) {
1919 // Sanity check even though JNI DetachCurrentThread() would have
1920 // returned JNI_ERR if there was a Java frame. JavaThread exit
1921 // should be done executing Java code by the time we get here.
1922 assert(!this->has_last_Java_frame(),
1923 "should not have a Java frame when detaching or exiting");
1924 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1925 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1926 }
1927
1928 // These things needs to be done while we are still a Java Thread. Make sure that thread
1929 // is in a consistent state, in case GC happens
1930 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1931
1932 if (active_handles() != NULL) {
1933 JNIHandleBlock* block = active_handles();
1934 set_active_handles(NULL);
1935 JNIHandleBlock::release_block(block);
1936 }
1937
1938 if (free_handle_block() != NULL) {
1939 JNIHandleBlock* block = free_handle_block();
1940 set_free_handle_block(NULL);
1941 JNIHandleBlock::release_block(block);
1942 }
1943
1944 // These have to be removed while this is still a valid thread.
1945 remove_stack_guard_pages();
1946
1947 if (UseTLAB) {
1948 tlab().make_parsable(true); // retire TLAB
1949 }
1950
1951 if (JvmtiEnv::environments_might_exist()) {
1952 JvmtiExport::cleanup_thread(this);
1953 }
1954
1955 // We must flush any deferred card marks and other various GC barrier
1956 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
1957 // before removing a thread from the list of active threads.
1958 BarrierSet::barrier_set()->on_thread_detach(this);
1959
1960 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
1961 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
1962 os::current_thread_id());
1963
1964 if (log_is_enabled(Debug, os, thread, timer)) {
1965 _timer_exit_phase3.stop();
1966 _timer_exit_phase4.start();
1967 }
1968 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1969 Threads::remove(this);
1970
1971 if (log_is_enabled(Debug, os, thread, timer)) {
1972 _timer_exit_phase4.stop();
1973 ResourceMark rm(this);
1974 log_debug(os, thread, timer)("name='%s'"
1975 ", exit-phase1=" JLONG_FORMAT
1976 ", exit-phase2=" JLONG_FORMAT
1977 ", exit-phase3=" JLONG_FORMAT
1978 ", exit-phase4=" JLONG_FORMAT,
1979 get_thread_name(),
1980 _timer_exit_phase1.milliseconds(),
1981 _timer_exit_phase2.milliseconds(),
1982 _timer_exit_phase3.milliseconds(),
1983 _timer_exit_phase4.milliseconds());
1984 }
1985 }
1986
1987 void JavaThread::cleanup_failed_attach_current_thread() {
1988 if (active_handles() != NULL) {
1989 JNIHandleBlock* block = active_handles();
1990 set_active_handles(NULL);
1991 JNIHandleBlock::release_block(block);
1992 }
1993
1994 if (free_handle_block() != NULL) {
1995 JNIHandleBlock* block = free_handle_block();
1996 set_free_handle_block(NULL);
1997 JNIHandleBlock::release_block(block);
1998 }
1999
2000 // These have to be removed while this is still a valid thread.
2001 remove_stack_guard_pages();
2002
2003 if (UseTLAB) {
2004 tlab().make_parsable(true); // retire TLAB, if any
2005 }
2006
2007 BarrierSet::barrier_set()->on_thread_detach(this);
2008
2009 Threads::remove(this);
2010 this->smr_delete();
2011 }
2012
2013 JavaThread* JavaThread::active() {
2014 Thread* thread = Thread::current();
2015 if (thread->is_Java_thread()) {
2016 return (JavaThread*) thread;
2017 } else {
2018 assert(thread->is_VM_thread(), "this must be a vm thread");
2019 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2020 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2021 assert(ret->is_Java_thread(), "must be a Java thread");
2022 return ret;
2023 }
2024 }
2025
2026 bool JavaThread::is_lock_owned(address adr) const {
2027 if (Thread::is_lock_owned(adr)) return true;
2028
2029 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2030 if (chunk->contains(adr)) return true;
2031 }
2032
2033 return false;
2034 }
2035
2036
2037 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2038 chunk->set_next(monitor_chunks());
2039 set_monitor_chunks(chunk);
2040 }
2041
2042 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2043 guarantee(monitor_chunks() != NULL, "must be non empty");
2044 if (monitor_chunks() == chunk) {
2045 set_monitor_chunks(chunk->next());
2046 } else {
2047 MonitorChunk* prev = monitor_chunks();
2048 while (prev->next() != chunk) prev = prev->next();
2049 prev->set_next(chunk->next());
2050 }
2051 }
2052
2053 // JVM support.
2054
2055 // Note: this function shouldn't block if it's called in
2056 // _thread_in_native_trans state (such as from
2057 // check_special_condition_for_native_trans()).
2058 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2059
2060 if (has_last_Java_frame() && has_async_condition()) {
2061 // If we are at a polling page safepoint (not a poll return)
2062 // then we must defer async exception because live registers
2063 // will be clobbered by the exception path. Poll return is
2064 // ok because the call we a returning from already collides
2065 // with exception handling registers and so there is no issue.
2066 // (The exception handling path kills call result registers but
2067 // this is ok since the exception kills the result anyway).
2068
2069 if (is_at_poll_safepoint()) {
2070 // if the code we are returning to has deoptimized we must defer
2071 // the exception otherwise live registers get clobbered on the
2072 // exception path before deoptimization is able to retrieve them.
2073 //
2074 RegisterMap map(this, false);
2075 frame caller_fr = last_frame().sender(&map);
2076 assert(caller_fr.is_compiled_frame(), "what?");
2077 if (caller_fr.is_deoptimized_frame()) {
2078 log_info(exceptions)("deferred async exception at compiled safepoint");
2079 return;
2080 }
2081 }
2082 }
2083
2084 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2085 if (condition == _no_async_condition) {
2086 // Conditions have changed since has_special_runtime_exit_condition()
2087 // was called:
2088 // - if we were here only because of an external suspend request,
2089 // then that was taken care of above (or cancelled) so we are done
2090 // - if we were here because of another async request, then it has
2091 // been cleared between the has_special_runtime_exit_condition()
2092 // and now so again we are done
2093 return;
2094 }
2095
2096 // Check for pending async. exception
2097 if (_pending_async_exception != NULL) {
2098 // Only overwrite an already pending exception, if it is not a threadDeath.
2099 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2100
2101 // We cannot call Exceptions::_throw(...) here because we cannot block
2102 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2103
2104 LogTarget(Info, exceptions) lt;
2105 if (lt.is_enabled()) {
2106 ResourceMark rm;
2107 LogStream ls(lt);
2108 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2109 if (has_last_Java_frame()) {
2110 frame f = last_frame();
2111 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2112 }
2113 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2114 }
2115 _pending_async_exception = NULL;
2116 clear_has_async_exception();
2117 }
2118 }
2119
2120 if (check_unsafe_error &&
2121 condition == _async_unsafe_access_error && !has_pending_exception()) {
2122 condition = _no_async_condition; // done
2123 switch (thread_state()) {
2124 case _thread_in_vm: {
2125 JavaThread* THREAD = this;
2126 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2127 }
2128 case _thread_in_native: {
2129 ThreadInVMfromNative tiv(this);
2130 JavaThread* THREAD = this;
2131 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2132 }
2133 case _thread_in_Java: {
2134 ThreadInVMfromJava tiv(this);
2135 JavaThread* THREAD = this;
2136 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2137 }
2138 default:
2139 ShouldNotReachHere();
2140 }
2141 }
2142
2143 assert(condition == _no_async_condition || has_pending_exception() ||
2144 (!check_unsafe_error && condition == _async_unsafe_access_error),
2145 "must have handled the async condition, if no exception");
2146 }
2147
2148 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2149 //
2150 // Check for pending external suspend. Internal suspend requests do
2151 // not use handle_special_runtime_exit_condition().
2152 // If JNIEnv proxies are allowed, don't self-suspend if the target
2153 // thread is not the current thread. In older versions of jdbx, jdbx
2154 // threads could call into the VM with another thread's JNIEnv so we
2155 // can be here operating on behalf of a suspended thread (4432884).
2156 bool do_self_suspend = is_external_suspend_with_lock();
2157 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2158 //
2159 // Because thread is external suspended the safepoint code will count
2160 // thread as at a safepoint. This can be odd because we can be here
2161 // as _thread_in_Java which would normally transition to _thread_blocked
2162 // at a safepoint. We would like to mark the thread as _thread_blocked
2163 // before calling java_suspend_self like all other callers of it but
2164 // we must then observe proper safepoint protocol. (We can't leave
2165 // _thread_blocked with a safepoint in progress). However we can be
2166 // here as _thread_in_native_trans so we can't use a normal transition
2167 // constructor/destructor pair because they assert on that type of
2168 // transition. We could do something like:
2169 //
2170 // JavaThreadState state = thread_state();
2171 // set_thread_state(_thread_in_vm);
2172 // {
2173 // ThreadBlockInVM tbivm(this);
2174 // java_suspend_self()
2175 // }
2176 // set_thread_state(_thread_in_vm_trans);
2177 // if (safepoint) block;
2178 // set_thread_state(state);
2179 //
2180 // but that is pretty messy. Instead we just go with the way the
2181 // code has worked before and note that this is the only path to
2182 // java_suspend_self that doesn't put the thread in _thread_blocked
2183 // mode.
2184
2185 frame_anchor()->make_walkable(this);
2186 java_suspend_self();
2187
2188 // We might be here for reasons in addition to the self-suspend request
2189 // so check for other async requests.
2190 }
2191
2192 if (check_asyncs) {
2193 check_and_handle_async_exceptions();
2194 }
2195
2196 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
2197 }
2198
2199 void JavaThread::send_thread_stop(oop java_throwable) {
2200 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2201 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2202 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2203
2204 // Do not throw asynchronous exceptions against the compiler thread
2205 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2206 if (!can_call_java()) return;
2207
2208 {
2209 // Actually throw the Throwable against the target Thread - however
2210 // only if there is no thread death exception installed already.
2211 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2212 // If the topmost frame is a runtime stub, then we are calling into
2213 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2214 // must deoptimize the caller before continuing, as the compiled exception handler table
2215 // may not be valid
2216 if (has_last_Java_frame()) {
2217 frame f = last_frame();
2218 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2219 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2220 RegisterMap reg_map(this, UseBiasedLocking);
2221 frame compiled_frame = f.sender(®_map);
2222 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2223 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2224 }
2225 }
2226 }
2227
2228 // Set async. pending exception in thread.
2229 set_pending_async_exception(java_throwable);
2230
2231 if (log_is_enabled(Info, exceptions)) {
2232 ResourceMark rm;
2233 log_info(exceptions)("Pending Async. exception installed of type: %s",
2234 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2235 }
2236 // for AbortVMOnException flag
2237 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2238 }
2239 }
2240
2241
2242 // Interrupt thread so it will wake up from a potential wait()
2243 Thread::interrupt(this);
2244 }
2245
2246 // External suspension mechanism.
2247 //
2248 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2249 // to any VM_locks and it is at a transition
2250 // Self-suspension will happen on the transition out of the vm.
2251 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2252 //
2253 // Guarantees on return:
2254 // + Target thread will not execute any new bytecode (that's why we need to
2255 // force a safepoint)
2256 // + Target thread will not enter any new monitors
2257 //
2258 void JavaThread::java_suspend() {
2259 ThreadsListHandle tlh;
2260 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2261 return;
2262 }
2263
2264 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2265 if (!is_external_suspend()) {
2266 // a racing resume has cancelled us; bail out now
2267 return;
2268 }
2269
2270 // suspend is done
2271 uint32_t debug_bits = 0;
2272 // Warning: is_ext_suspend_completed() may temporarily drop the
2273 // SR_lock to allow the thread to reach a stable thread state if
2274 // it is currently in a transient thread state.
2275 if (is_ext_suspend_completed(false /* !called_by_wait */,
2276 SuspendRetryDelay, &debug_bits)) {
2277 return;
2278 }
2279 }
2280
2281 VM_ThreadSuspend vm_suspend;
2282 VMThread::execute(&vm_suspend);
2283 }
2284
2285 // Part II of external suspension.
2286 // A JavaThread self suspends when it detects a pending external suspend
2287 // request. This is usually on transitions. It is also done in places
2288 // where continuing to the next transition would surprise the caller,
2289 // e.g., monitor entry.
2290 //
2291 // Returns the number of times that the thread self-suspended.
2292 //
2293 // Note: DO NOT call java_suspend_self() when you just want to block current
2294 // thread. java_suspend_self() is the second stage of cooperative
2295 // suspension for external suspend requests and should only be used
2296 // to complete an external suspend request.
2297 //
2298 int JavaThread::java_suspend_self() {
2299 int ret = 0;
2300
2301 // we are in the process of exiting so don't suspend
2302 if (is_exiting()) {
2303 clear_external_suspend();
2304 return ret;
2305 }
2306
2307 assert(_anchor.walkable() ||
2308 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2309 "must have walkable stack");
2310
2311 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2312
2313 assert(!this->is_ext_suspended(),
2314 "a thread trying to self-suspend should not already be suspended");
2315
2316 if (this->is_suspend_equivalent()) {
2317 // If we are self-suspending as a result of the lifting of a
2318 // suspend equivalent condition, then the suspend_equivalent
2319 // flag is not cleared until we set the ext_suspended flag so
2320 // that wait_for_ext_suspend_completion() returns consistent
2321 // results.
2322 this->clear_suspend_equivalent();
2323 }
2324
2325 // A racing resume may have cancelled us before we grabbed SR_lock
2326 // above. Or another external suspend request could be waiting for us
2327 // by the time we return from SR_lock()->wait(). The thread
2328 // that requested the suspension may already be trying to walk our
2329 // stack and if we return now, we can change the stack out from under
2330 // it. This would be a "bad thing (TM)" and cause the stack walker
2331 // to crash. We stay self-suspended until there are no more pending
2332 // external suspend requests.
2333 while (is_external_suspend()) {
2334 ret++;
2335 this->set_ext_suspended();
2336
2337 // _ext_suspended flag is cleared by java_resume()
2338 while (is_ext_suspended()) {
2339 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2340 }
2341 }
2342
2343 return ret;
2344 }
2345
2346 #ifdef ASSERT
2347 // Verify the JavaThread has not yet been published in the Threads::list, and
2348 // hence doesn't need protection from concurrent access at this stage.
2349 void JavaThread::verify_not_published() {
2350 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2351 // since an unpublished JavaThread doesn't participate in the
2352 // Thread-SMR protocol for keeping a ThreadsList alive.
2353 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2354 }
2355 #endif
2356
2357 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2358 // progress or when _suspend_flags is non-zero.
2359 // Current thread needs to self-suspend if there is a suspend request and/or
2360 // block if a safepoint is in progress.
2361 // Async exception ISN'T checked.
2362 // Note only the ThreadInVMfromNative transition can call this function
2363 // directly and when thread state is _thread_in_native_trans
2364 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2365 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2366
2367 JavaThread *curJT = JavaThread::current();
2368 bool do_self_suspend = thread->is_external_suspend();
2369
2370 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2371
2372 // If JNIEnv proxies are allowed, don't self-suspend if the target
2373 // thread is not the current thread. In older versions of jdbx, jdbx
2374 // threads could call into the VM with another thread's JNIEnv so we
2375 // can be here operating on behalf of a suspended thread (4432884).
2376 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2377 JavaThreadState state = thread->thread_state();
2378
2379 // We mark this thread_blocked state as a suspend-equivalent so
2380 // that a caller to is_ext_suspend_completed() won't be confused.
2381 // The suspend-equivalent state is cleared by java_suspend_self().
2382 thread->set_suspend_equivalent();
2383
2384 // If the safepoint code sees the _thread_in_native_trans state, it will
2385 // wait until the thread changes to other thread state. There is no
2386 // guarantee on how soon we can obtain the SR_lock and complete the
2387 // self-suspend request. It would be a bad idea to let safepoint wait for
2388 // too long. Temporarily change the state to _thread_blocked to
2389 // let the VM thread know that this thread is ready for GC. The problem
2390 // of changing thread state is that safepoint could happen just after
2391 // java_suspend_self() returns after being resumed, and VM thread will
2392 // see the _thread_blocked state. We must check for safepoint
2393 // after restoring the state and make sure we won't leave while a safepoint
2394 // is in progress.
2395 thread->set_thread_state(_thread_blocked);
2396 thread->java_suspend_self();
2397 thread->set_thread_state(state);
2398
2399 InterfaceSupport::serialize_thread_state_with_handler(thread);
2400 }
2401
2402 SafepointMechanism::block_if_requested(curJT);
2403
2404 if (thread->is_deopt_suspend()) {
2405 thread->clear_deopt_suspend();
2406 RegisterMap map(thread, false);
2407 frame f = thread->last_frame();
2408 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2409 f = f.sender(&map);
2410 }
2411 if (f.id() == thread->must_deopt_id()) {
2412 thread->clear_must_deopt_id();
2413 f.deoptimize(thread);
2414 } else {
2415 fatal("missed deoptimization!");
2416 }
2417 }
2418
2419 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
2420 }
2421
2422 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2423 // progress or when _suspend_flags is non-zero.
2424 // Current thread needs to self-suspend if there is a suspend request and/or
2425 // block if a safepoint is in progress.
2426 // Also check for pending async exception (not including unsafe access error).
2427 // Note only the native==>VM/Java barriers can call this function and when
2428 // thread state is _thread_in_native_trans.
2429 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2430 check_safepoint_and_suspend_for_native_trans(thread);
2431
2432 if (thread->has_async_exception()) {
2433 // We are in _thread_in_native_trans state, don't handle unsafe
2434 // access error since that may block.
2435 thread->check_and_handle_async_exceptions(false);
2436 }
2437 }
2438
2439 // This is a variant of the normal
2440 // check_special_condition_for_native_trans with slightly different
2441 // semantics for use by critical native wrappers. It does all the
2442 // normal checks but also performs the transition back into
2443 // thread_in_Java state. This is required so that critical natives
2444 // can potentially block and perform a GC if they are the last thread
2445 // exiting the GCLocker.
2446 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2447 check_special_condition_for_native_trans(thread);
2448
2449 // Finish the transition
2450 thread->set_thread_state(_thread_in_Java);
2451
2452 if (thread->do_critical_native_unlock()) {
2453 ThreadInVMfromJavaNoAsyncException tiv(thread);
2454 GCLocker::unlock_critical(thread);
2455 thread->clear_critical_native_unlock();
2456 }
2457 }
2458
2459 // We need to guarantee the Threads_lock here, since resumes are not
2460 // allowed during safepoint synchronization
2461 // Can only resume from an external suspension
2462 void JavaThread::java_resume() {
2463 assert_locked_or_safepoint(Threads_lock);
2464
2465 // Sanity check: thread is gone, has started exiting or the thread
2466 // was not externally suspended.
2467 ThreadsListHandle tlh;
2468 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2469 return;
2470 }
2471
2472 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2473
2474 clear_external_suspend();
2475
2476 if (is_ext_suspended()) {
2477 clear_ext_suspended();
2478 SR_lock()->notify_all();
2479 }
2480 }
2481
2482 size_t JavaThread::_stack_red_zone_size = 0;
2483 size_t JavaThread::_stack_yellow_zone_size = 0;
2484 size_t JavaThread::_stack_reserved_zone_size = 0;
2485 size_t JavaThread::_stack_shadow_zone_size = 0;
2486
2487 void JavaThread::create_stack_guard_pages() {
2488 if (!os::uses_stack_guard_pages() ||
2489 _stack_guard_state != stack_guard_unused ||
2490 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2491 log_info(os, thread)("Stack guard page creation for thread "
2492 UINTX_FORMAT " disabled", os::current_thread_id());
2493 return;
2494 }
2495 address low_addr = stack_end();
2496 size_t len = stack_guard_zone_size();
2497
2498 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2499 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2500
2501 int must_commit = os::must_commit_stack_guard_pages();
2502 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2503
2504 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2505 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2506 return;
2507 }
2508
2509 if (os::guard_memory((char *) low_addr, len)) {
2510 _stack_guard_state = stack_guard_enabled;
2511 } else {
2512 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2513 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2514 if (os::uncommit_memory((char *) low_addr, len)) {
2515 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2516 }
2517 return;
2518 }
2519
2520 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2521 PTR_FORMAT "-" PTR_FORMAT ".",
2522 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2523 }
2524
2525 void JavaThread::remove_stack_guard_pages() {
2526 assert(Thread::current() == this, "from different thread");
2527 if (_stack_guard_state == stack_guard_unused) return;
2528 address low_addr = stack_end();
2529 size_t len = stack_guard_zone_size();
2530
2531 if (os::must_commit_stack_guard_pages()) {
2532 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2533 _stack_guard_state = stack_guard_unused;
2534 } else {
2535 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2536 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2537 return;
2538 }
2539 } else {
2540 if (_stack_guard_state == stack_guard_unused) return;
2541 if (os::unguard_memory((char *) low_addr, len)) {
2542 _stack_guard_state = stack_guard_unused;
2543 } else {
2544 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2545 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2546 return;
2547 }
2548 }
2549
2550 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2551 PTR_FORMAT "-" PTR_FORMAT ".",
2552 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2553 }
2554
2555 void JavaThread::enable_stack_reserved_zone() {
2556 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2557 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2558
2559 // The base notation is from the stack's point of view, growing downward.
2560 // We need to adjust it to work correctly with guard_memory()
2561 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2562
2563 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2564 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2565
2566 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2567 _stack_guard_state = stack_guard_enabled;
2568 } else {
2569 warning("Attempt to guard stack reserved zone failed.");
2570 }
2571 enable_register_stack_guard();
2572 }
2573
2574 void JavaThread::disable_stack_reserved_zone() {
2575 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2576 assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled");
2577
2578 // Simply return if called for a thread that does not use guard pages.
2579 if (_stack_guard_state == stack_guard_unused) return;
2580
2581 // The base notation is from the stack's point of view, growing downward.
2582 // We need to adjust it to work correctly with guard_memory()
2583 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2584
2585 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2586 _stack_guard_state = stack_guard_reserved_disabled;
2587 } else {
2588 warning("Attempt to unguard stack reserved zone failed.");
2589 }
2590 disable_register_stack_guard();
2591 }
2592
2593 void JavaThread::enable_stack_yellow_reserved_zone() {
2594 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2595 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2596
2597 // The base notation is from the stacks point of view, growing downward.
2598 // We need to adjust it to work correctly with guard_memory()
2599 address base = stack_red_zone_base();
2600
2601 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2602 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2603
2604 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2605 _stack_guard_state = stack_guard_enabled;
2606 } else {
2607 warning("Attempt to guard stack yellow zone failed.");
2608 }
2609 enable_register_stack_guard();
2610 }
2611
2612 void JavaThread::disable_stack_yellow_reserved_zone() {
2613 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2614 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2615
2616 // Simply return if called for a thread that does not use guard pages.
2617 if (_stack_guard_state == stack_guard_unused) return;
2618
2619 // The base notation is from the stacks point of view, growing downward.
2620 // We need to adjust it to work correctly with guard_memory()
2621 address base = stack_red_zone_base();
2622
2623 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2624 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2625 } else {
2626 warning("Attempt to unguard stack yellow zone failed.");
2627 }
2628 disable_register_stack_guard();
2629 }
2630
2631 void JavaThread::enable_stack_red_zone() {
2632 // The base notation is from the stacks point of view, growing downward.
2633 // We need to adjust it to work correctly with guard_memory()
2634 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2635 address base = stack_red_zone_base() - stack_red_zone_size();
2636
2637 guarantee(base < stack_base(), "Error calculating stack red zone");
2638 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2639
2640 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2641 warning("Attempt to guard stack red zone failed.");
2642 }
2643 }
2644
2645 void JavaThread::disable_stack_red_zone() {
2646 // The base notation is from the stacks point of view, growing downward.
2647 // We need to adjust it to work correctly with guard_memory()
2648 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2649 address base = stack_red_zone_base() - stack_red_zone_size();
2650 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2651 warning("Attempt to unguard stack red zone failed.");
2652 }
2653 }
2654
2655 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2656 // ignore is there is no stack
2657 if (!has_last_Java_frame()) return;
2658 // traverse the stack frames. Starts from top frame.
2659 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2660 frame* fr = fst.current();
2661 f(fr, fst.register_map());
2662 }
2663 }
2664
2665
2666 #ifndef PRODUCT
2667 // Deoptimization
2668 // Function for testing deoptimization
2669 void JavaThread::deoptimize() {
2670 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2671 StackFrameStream fst(this, UseBiasedLocking);
2672 bool deopt = false; // Dump stack only if a deopt actually happens.
2673 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2674 // Iterate over all frames in the thread and deoptimize
2675 for (; !fst.is_done(); fst.next()) {
2676 if (fst.current()->can_be_deoptimized()) {
2677
2678 if (only_at) {
2679 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2680 // consists of comma or carriage return separated numbers so
2681 // search for the current bci in that string.
2682 address pc = fst.current()->pc();
2683 nmethod* nm = (nmethod*) fst.current()->cb();
2684 ScopeDesc* sd = nm->scope_desc_at(pc);
2685 char buffer[8];
2686 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2687 size_t len = strlen(buffer);
2688 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2689 while (found != NULL) {
2690 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2691 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2692 // Check that the bci found is bracketed by terminators.
2693 break;
2694 }
2695 found = strstr(found + 1, buffer);
2696 }
2697 if (!found) {
2698 continue;
2699 }
2700 }
2701
2702 if (DebugDeoptimization && !deopt) {
2703 deopt = true; // One-time only print before deopt
2704 tty->print_cr("[BEFORE Deoptimization]");
2705 trace_frames();
2706 trace_stack();
2707 }
2708 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2709 }
2710 }
2711
2712 if (DebugDeoptimization && deopt) {
2713 tty->print_cr("[AFTER Deoptimization]");
2714 trace_frames();
2715 }
2716 }
2717
2718
2719 // Make zombies
2720 void JavaThread::make_zombies() {
2721 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2722 if (fst.current()->can_be_deoptimized()) {
2723 // it is a Java nmethod
2724 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2725 nm->make_not_entrant();
2726 }
2727 }
2728 }
2729 #endif // PRODUCT
2730
2731
2732 void JavaThread::deoptimized_wrt_marked_nmethods() {
2733 if (!has_last_Java_frame()) return;
2734 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2735 StackFrameStream fst(this, UseBiasedLocking);
2736 for (; !fst.is_done(); fst.next()) {
2737 if (fst.current()->should_be_deoptimized()) {
2738 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2739 }
2740 }
2741 }
2742
2743
2744 // If the caller is a NamedThread, then remember, in the current scope,
2745 // the given JavaThread in its _processed_thread field.
2746 class RememberProcessedThread: public StackObj {
2747 NamedThread* _cur_thr;
2748 public:
2749 RememberProcessedThread(JavaThread* jthr) {
2750 Thread* thread = Thread::current();
2751 if (thread->is_Named_thread()) {
2752 _cur_thr = (NamedThread *)thread;
2753 _cur_thr->set_processed_thread(jthr);
2754 } else {
2755 _cur_thr = NULL;
2756 }
2757 }
2758
2759 ~RememberProcessedThread() {
2760 if (_cur_thr) {
2761 _cur_thr->set_processed_thread(NULL);
2762 }
2763 }
2764 };
2765
2766 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2767 // Verify that the deferred card marks have been flushed.
2768 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2769
2770 // Traverse the GCHandles
2771 Thread::oops_do(f, cf);
2772
2773 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);)
2774
2775 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2776 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2777
2778 if (has_last_Java_frame()) {
2779 // Record JavaThread to GC thread
2780 RememberProcessedThread rpt(this);
2781
2782 // Traverse the privileged stack
2783 if (_privileged_stack_top != NULL) {
2784 _privileged_stack_top->oops_do(f);
2785 }
2786
2787 // traverse the registered growable array
2788 if (_array_for_gc != NULL) {
2789 for (int index = 0; index < _array_for_gc->length(); index++) {
2790 f->do_oop(_array_for_gc->adr_at(index));
2791 }
2792 }
2793
2794 // Traverse the monitor chunks
2795 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2796 chunk->oops_do(f);
2797 }
2798
2799 // Traverse the execution stack
2800 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2801 fst.current()->oops_do(f, cf, fst.register_map());
2802 }
2803 }
2804
2805 // callee_target is never live across a gc point so NULL it here should
2806 // it still contain a methdOop.
2807
2808 set_callee_target(NULL);
2809
2810 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2811 // If we have deferred set_locals there might be oops waiting to be
2812 // written
2813 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2814 if (list != NULL) {
2815 for (int i = 0; i < list->length(); i++) {
2816 list->at(i)->oops_do(f);
2817 }
2818 }
2819
2820 // Traverse instance variables at the end since the GC may be moving things
2821 // around using this function
2822 f->do_oop((oop*) &_threadObj);
2823 f->do_oop((oop*) &_vm_result);
2824 f->do_oop((oop*) &_exception_oop);
2825 f->do_oop((oop*) &_pending_async_exception);
2826
2827 if (jvmti_thread_state() != NULL) {
2828 jvmti_thread_state()->oops_do(f);
2829 }
2830 }
2831
2832 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2833 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2834 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2835
2836 if (has_last_Java_frame()) {
2837 // Traverse the execution stack
2838 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2839 fst.current()->nmethods_do(cf);
2840 }
2841 }
2842 }
2843
2844 void JavaThread::metadata_do(void f(Metadata*)) {
2845 if (has_last_Java_frame()) {
2846 // Traverse the execution stack to call f() on the methods in the stack
2847 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2848 fst.current()->metadata_do(f);
2849 }
2850 } else if (is_Compiler_thread()) {
2851 // need to walk ciMetadata in current compile tasks to keep alive.
2852 CompilerThread* ct = (CompilerThread*)this;
2853 if (ct->env() != NULL) {
2854 ct->env()->metadata_do(f);
2855 }
2856 CompileTask* task = ct->task();
2857 if (task != NULL) {
2858 task->metadata_do(f);
2859 }
2860 }
2861 }
2862
2863 // Printing
2864 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2865 switch (_thread_state) {
2866 case _thread_uninitialized: return "_thread_uninitialized";
2867 case _thread_new: return "_thread_new";
2868 case _thread_new_trans: return "_thread_new_trans";
2869 case _thread_in_native: return "_thread_in_native";
2870 case _thread_in_native_trans: return "_thread_in_native_trans";
2871 case _thread_in_vm: return "_thread_in_vm";
2872 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2873 case _thread_in_Java: return "_thread_in_Java";
2874 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2875 case _thread_blocked: return "_thread_blocked";
2876 case _thread_blocked_trans: return "_thread_blocked_trans";
2877 default: return "unknown thread state";
2878 }
2879 }
2880
2881 #ifndef PRODUCT
2882 void JavaThread::print_thread_state_on(outputStream *st) const {
2883 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2884 };
2885 void JavaThread::print_thread_state() const {
2886 print_thread_state_on(tty);
2887 }
2888 #endif // PRODUCT
2889
2890 // Called by Threads::print() for VM_PrintThreads operation
2891 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
2892 st->print_raw("\"");
2893 st->print_raw(get_thread_name());
2894 st->print_raw("\" ");
2895 oop thread_oop = threadObj();
2896 if (thread_oop != NULL) {
2897 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
2898 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2899 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2900 }
2901 Thread::print_on(st, print_extended_info);
2902 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2903 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2904 if (thread_oop != NULL) {
2905 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2906 }
2907 #ifndef PRODUCT
2908 print_thread_state_on(st);
2909 _safepoint_state->print_on(st);
2910 #endif // PRODUCT
2911 if (is_Compiler_thread()) {
2912 CompileTask *task = ((CompilerThread*)this)->task();
2913 if (task != NULL) {
2914 st->print(" Compiling: ");
2915 task->print(st, NULL, true, false);
2916 } else {
2917 st->print(" No compile task");
2918 }
2919 st->cr();
2920 }
2921 }
2922
2923 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
2924 st->print("%s", get_thread_name_string(buf, buflen));
2925 }
2926
2927 // Called by fatal error handler. The difference between this and
2928 // JavaThread::print() is that we can't grab lock or allocate memory.
2929 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2930 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2931 oop thread_obj = threadObj();
2932 if (thread_obj != NULL) {
2933 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2934 }
2935 st->print(" [");
2936 st->print("%s", _get_thread_state_name(_thread_state));
2937 if (osthread()) {
2938 st->print(", id=%d", osthread()->thread_id());
2939 }
2940 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2941 p2i(stack_end()), p2i(stack_base()));
2942 st->print("]");
2943
2944 ThreadsSMRSupport::print_info_on(this, st);
2945 return;
2946 }
2947
2948 // Verification
2949
2950 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2951
2952 void JavaThread::verify() {
2953 // Verify oops in the thread.
2954 oops_do(&VerifyOopClosure::verify_oop, NULL);
2955
2956 // Verify the stack frames.
2957 frames_do(frame_verify);
2958 }
2959
2960 // CR 6300358 (sub-CR 2137150)
2961 // Most callers of this method assume that it can't return NULL but a
2962 // thread may not have a name whilst it is in the process of attaching to
2963 // the VM - see CR 6412693, and there are places where a JavaThread can be
2964 // seen prior to having it's threadObj set (eg JNI attaching threads and
2965 // if vm exit occurs during initialization). These cases can all be accounted
2966 // for such that this method never returns NULL.
2967 const char* JavaThread::get_thread_name() const {
2968 #ifdef ASSERT
2969 // early safepoints can hit while current thread does not yet have TLS
2970 if (!SafepointSynchronize::is_at_safepoint()) {
2971 Thread *cur = Thread::current();
2972 if (!(cur->is_Java_thread() && cur == this)) {
2973 // Current JavaThreads are allowed to get their own name without
2974 // the Threads_lock.
2975 assert_locked_or_safepoint(Threads_lock);
2976 }
2977 }
2978 #endif // ASSERT
2979 return get_thread_name_string();
2980 }
2981
2982 // Returns a non-NULL representation of this thread's name, or a suitable
2983 // descriptive string if there is no set name
2984 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2985 const char* name_str;
2986 oop thread_obj = threadObj();
2987 if (thread_obj != NULL) {
2988 oop name = java_lang_Thread::name(thread_obj);
2989 if (name != NULL) {
2990 if (buf == NULL) {
2991 name_str = java_lang_String::as_utf8_string(name);
2992 } else {
2993 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2994 }
2995 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2996 name_str = "<no-name - thread is attaching>";
2997 } else {
2998 name_str = Thread::name();
2999 }
3000 } else {
3001 name_str = Thread::name();
3002 }
3003 assert(name_str != NULL, "unexpected NULL thread name");
3004 return name_str;
3005 }
3006
3007
3008 const char* JavaThread::get_threadgroup_name() const {
3009 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3010 oop thread_obj = threadObj();
3011 if (thread_obj != NULL) {
3012 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3013 if (thread_group != NULL) {
3014 // ThreadGroup.name can be null
3015 return java_lang_ThreadGroup::name(thread_group);
3016 }
3017 }
3018 return NULL;
3019 }
3020
3021 const char* JavaThread::get_parent_name() const {
3022 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3023 oop thread_obj = threadObj();
3024 if (thread_obj != NULL) {
3025 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3026 if (thread_group != NULL) {
3027 oop parent = java_lang_ThreadGroup::parent(thread_group);
3028 if (parent != NULL) {
3029 // ThreadGroup.name can be null
3030 return java_lang_ThreadGroup::name(parent);
3031 }
3032 }
3033 }
3034 return NULL;
3035 }
3036
3037 ThreadPriority JavaThread::java_priority() const {
3038 oop thr_oop = threadObj();
3039 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3040 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3041 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3042 return priority;
3043 }
3044
3045 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3046
3047 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3048 // Link Java Thread object <-> C++ Thread
3049
3050 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3051 // and put it into a new Handle. The Handle "thread_oop" can then
3052 // be used to pass the C++ thread object to other methods.
3053
3054 // Set the Java level thread object (jthread) field of the
3055 // new thread (a JavaThread *) to C++ thread object using the
3056 // "thread_oop" handle.
3057
3058 // Set the thread field (a JavaThread *) of the
3059 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3060
3061 Handle thread_oop(Thread::current(),
3062 JNIHandles::resolve_non_null(jni_thread));
3063 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3064 "must be initialized");
3065 set_threadObj(thread_oop());
3066 java_lang_Thread::set_thread(thread_oop(), this);
3067
3068 if (prio == NoPriority) {
3069 prio = java_lang_Thread::priority(thread_oop());
3070 assert(prio != NoPriority, "A valid priority should be present");
3071 }
3072
3073 // Push the Java priority down to the native thread; needs Threads_lock
3074 Thread::set_priority(this, prio);
3075
3076 // Add the new thread to the Threads list and set it in motion.
3077 // We must have threads lock in order to call Threads::add.
3078 // It is crucial that we do not block before the thread is
3079 // added to the Threads list for if a GC happens, then the java_thread oop
3080 // will not be visited by GC.
3081 Threads::add(this);
3082 }
3083
3084 oop JavaThread::current_park_blocker() {
3085 // Support for JSR-166 locks
3086 oop thread_oop = threadObj();
3087 if (thread_oop != NULL &&
3088 JDK_Version::current().supports_thread_park_blocker()) {
3089 return java_lang_Thread::park_blocker(thread_oop);
3090 }
3091 return NULL;
3092 }
3093
3094
3095 void JavaThread::print_stack_on(outputStream* st) {
3096 if (!has_last_Java_frame()) return;
3097 ResourceMark rm;
3098 HandleMark hm;
3099
3100 RegisterMap reg_map(this);
3101 vframe* start_vf = last_java_vframe(®_map);
3102 int count = 0;
3103 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3104 if (f->is_java_frame()) {
3105 javaVFrame* jvf = javaVFrame::cast(f);
3106 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3107
3108 // Print out lock information
3109 if (JavaMonitorsInStackTrace) {
3110 jvf->print_lock_info_on(st, count);
3111 }
3112 } else {
3113 // Ignore non-Java frames
3114 }
3115
3116 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3117 count++;
3118 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3119 }
3120 }
3121
3122
3123 // JVMTI PopFrame support
3124 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3125 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3126 if (in_bytes(size_in_bytes) != 0) {
3127 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3128 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3129 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3130 }
3131 }
3132
3133 void* JavaThread::popframe_preserved_args() {
3134 return _popframe_preserved_args;
3135 }
3136
3137 ByteSize JavaThread::popframe_preserved_args_size() {
3138 return in_ByteSize(_popframe_preserved_args_size);
3139 }
3140
3141 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3142 int sz = in_bytes(popframe_preserved_args_size());
3143 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3144 return in_WordSize(sz / wordSize);
3145 }
3146
3147 void JavaThread::popframe_free_preserved_args() {
3148 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3149 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3150 _popframe_preserved_args = NULL;
3151 _popframe_preserved_args_size = 0;
3152 }
3153
3154 #ifndef PRODUCT
3155
3156 void JavaThread::trace_frames() {
3157 tty->print_cr("[Describe stack]");
3158 int frame_no = 1;
3159 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3160 tty->print(" %d. ", frame_no++);
3161 fst.current()->print_value_on(tty, this);
3162 tty->cr();
3163 }
3164 }
3165
3166 class PrintAndVerifyOopClosure: public OopClosure {
3167 protected:
3168 template <class T> inline void do_oop_work(T* p) {
3169 oop obj = RawAccess<>::oop_load(p);
3170 if (obj == NULL) return;
3171 tty->print(INTPTR_FORMAT ": ", p2i(p));
3172 if (oopDesc::is_oop_or_null(obj)) {
3173 if (obj->is_objArray()) {
3174 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3175 } else {
3176 obj->print();
3177 }
3178 } else {
3179 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3180 }
3181 tty->cr();
3182 }
3183 public:
3184 virtual void do_oop(oop* p) { do_oop_work(p); }
3185 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3186 };
3187
3188
3189 static void oops_print(frame* f, const RegisterMap *map) {
3190 PrintAndVerifyOopClosure print;
3191 f->print_value();
3192 f->oops_do(&print, NULL, (RegisterMap*)map);
3193 }
3194
3195 // Print our all the locations that contain oops and whether they are
3196 // valid or not. This useful when trying to find the oldest frame
3197 // where an oop has gone bad since the frame walk is from youngest to
3198 // oldest.
3199 void JavaThread::trace_oops() {
3200 tty->print_cr("[Trace oops]");
3201 frames_do(oops_print);
3202 }
3203
3204
3205 #ifdef ASSERT
3206 // Print or validate the layout of stack frames
3207 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3208 ResourceMark rm;
3209 PRESERVE_EXCEPTION_MARK;
3210 FrameValues values;
3211 int frame_no = 0;
3212 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3213 fst.current()->describe(values, ++frame_no);
3214 if (depth == frame_no) break;
3215 }
3216 if (validate_only) {
3217 values.validate();
3218 } else {
3219 tty->print_cr("[Describe stack layout]");
3220 values.print(this);
3221 }
3222 }
3223 #endif
3224
3225 void JavaThread::trace_stack_from(vframe* start_vf) {
3226 ResourceMark rm;
3227 int vframe_no = 1;
3228 for (vframe* f = start_vf; f; f = f->sender()) {
3229 if (f->is_java_frame()) {
3230 javaVFrame::cast(f)->print_activation(vframe_no++);
3231 } else {
3232 f->print();
3233 }
3234 if (vframe_no > StackPrintLimit) {
3235 tty->print_cr("...<more frames>...");
3236 return;
3237 }
3238 }
3239 }
3240
3241
3242 void JavaThread::trace_stack() {
3243 if (!has_last_Java_frame()) return;
3244 ResourceMark rm;
3245 HandleMark hm;
3246 RegisterMap reg_map(this);
3247 trace_stack_from(last_java_vframe(®_map));
3248 }
3249
3250
3251 #endif // PRODUCT
3252
3253
3254 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3255 assert(reg_map != NULL, "a map must be given");
3256 frame f = last_frame();
3257 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3258 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3259 }
3260 return NULL;
3261 }
3262
3263
3264 Klass* JavaThread::security_get_caller_class(int depth) {
3265 vframeStream vfst(this);
3266 vfst.security_get_caller_frame(depth);
3267 if (!vfst.at_end()) {
3268 return vfst.method()->method_holder();
3269 }
3270 return NULL;
3271 }
3272
3273 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3274 assert(thread->is_Compiler_thread(), "must be compiler thread");
3275 CompileBroker::compiler_thread_loop();
3276 }
3277
3278 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3279 NMethodSweeper::sweeper_loop();
3280 }
3281
3282 // Create a CompilerThread
3283 CompilerThread::CompilerThread(CompileQueue* queue,
3284 CompilerCounters* counters)
3285 : JavaThread(&compiler_thread_entry) {
3286 _env = NULL;
3287 _log = NULL;
3288 _task = NULL;
3289 _queue = queue;
3290 _counters = counters;
3291 _buffer_blob = NULL;
3292 _compiler = NULL;
3293
3294 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3295 resource_area()->bias_to(mtCompiler);
3296
3297 #ifndef PRODUCT
3298 _ideal_graph_printer = NULL;
3299 #endif
3300 }
3301
3302 CompilerThread::~CompilerThread() {
3303 // Delete objects which were allocated on heap.
3304 delete _counters;
3305 }
3306
3307 bool CompilerThread::can_call_java() const {
3308 return _compiler != NULL && _compiler->is_jvmci();
3309 }
3310
3311 // Create sweeper thread
3312 CodeCacheSweeperThread::CodeCacheSweeperThread()
3313 : JavaThread(&sweeper_thread_entry) {
3314 _scanned_compiled_method = NULL;
3315 }
3316
3317 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3318 JavaThread::oops_do(f, cf);
3319 if (_scanned_compiled_method != NULL && cf != NULL) {
3320 // Safepoints can occur when the sweeper is scanning an nmethod so
3321 // process it here to make sure it isn't unloaded in the middle of
3322 // a scan.
3323 cf->do_code_blob(_scanned_compiled_method);
3324 }
3325 }
3326
3327 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3328 JavaThread::nmethods_do(cf);
3329 if (_scanned_compiled_method != NULL && cf != NULL) {
3330 // Safepoints can occur when the sweeper is scanning an nmethod so
3331 // process it here to make sure it isn't unloaded in the middle of
3332 // a scan.
3333 cf->do_code_blob(_scanned_compiled_method);
3334 }
3335 }
3336
3337
3338 // ======= Threads ========
3339
3340 // The Threads class links together all active threads, and provides
3341 // operations over all threads. It is protected by the Threads_lock,
3342 // which is also used in other global contexts like safepointing.
3343 // ThreadsListHandles are used to safely perform operations on one
3344 // or more threads without the risk of the thread exiting during the
3345 // operation.
3346 //
3347 // Note: The Threads_lock is currently more widely used than we
3348 // would like. We are actively migrating Threads_lock uses to other
3349 // mechanisms in order to reduce Threads_lock contention.
3350
3351 JavaThread* Threads::_thread_list = NULL;
3352 int Threads::_number_of_threads = 0;
3353 int Threads::_number_of_non_daemon_threads = 0;
3354 int Threads::_return_code = 0;
3355 int Threads::_thread_claim_parity = 0;
3356 size_t JavaThread::_stack_size_at_create = 0;
3357
3358 #ifdef ASSERT
3359 bool Threads::_vm_complete = false;
3360 #endif
3361
3362 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3363 Prefetch::read((void*)addr, prefetch_interval);
3364 return *addr;
3365 }
3366
3367 // Possibly the ugliest for loop the world has seen. C++ does not allow
3368 // multiple types in the declaration section of the for loop. In this case
3369 // we are only dealing with pointers and hence can cast them. It looks ugly
3370 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3371 #define DO_JAVA_THREADS(LIST, X) \
3372 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3373 *MACRO_list = (JavaThread*)(LIST), \
3374 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3375 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3376 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3377 MACRO_current_p != MACRO_end; \
3378 MACRO_current_p++, \
3379 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3380
3381 // All JavaThreads
3382 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3383
3384 // All non-JavaThreads (i.e., every non-JavaThread in the system).
3385 void Threads::non_java_threads_do(ThreadClosure* tc) {
3386 // Someday we could have a table or list of all non-JavaThreads.
3387 // For now, just manually iterate through them.
3388 tc->do_thread(VMThread::vm_thread());
3389 if (Universe::heap() != NULL) {
3390 Universe::heap()->gc_threads_do(tc);
3391 }
3392 WatcherThread *wt = WatcherThread::watcher_thread();
3393 // Strictly speaking, the following NULL check isn't sufficient to make sure
3394 // the data for WatcherThread is still valid upon being examined. However,
3395 // considering that WatchThread terminates when the VM is on the way to
3396 // exit at safepoint, the chance of the above is extremely small. The right
3397 // way to prevent termination of WatcherThread would be to acquire
3398 // Terminator_lock, but we can't do that without violating the lock rank
3399 // checking in some cases.
3400 if (wt != NULL) {
3401 tc->do_thread(wt);
3402 }
3403
3404 #if INCLUDE_JFR
3405 Thread* sampler_thread = Jfr::sampler_thread();
3406 if (sampler_thread != NULL) {
3407 tc->do_thread(sampler_thread);
3408 }
3409
3410 #endif
3411
3412 // If CompilerThreads ever become non-JavaThreads, add them here
3413 }
3414
3415 // All JavaThreads
3416 void Threads::java_threads_do(ThreadClosure* tc) {
3417 assert_locked_or_safepoint(Threads_lock);
3418 // ALL_JAVA_THREADS iterates through all JavaThreads.
3419 ALL_JAVA_THREADS(p) {
3420 tc->do_thread(p);
3421 }
3422 }
3423
3424 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) {
3425 assert_locked_or_safepoint(Threads_lock);
3426 java_threads_do(tc);
3427 tc->do_thread(VMThread::vm_thread());
3428 }
3429
3430 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3431 void Threads::threads_do(ThreadClosure* tc) {
3432 assert_locked_or_safepoint(Threads_lock);
3433 java_threads_do(tc);
3434 non_java_threads_do(tc);
3435 }
3436
3437 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3438 int cp = Threads::thread_claim_parity();
3439 ALL_JAVA_THREADS(p) {
3440 if (p->claim_oops_do(is_par, cp)) {
3441 tc->do_thread(p);
3442 }
3443 }
3444 VMThread* vmt = VMThread::vm_thread();
3445 if (vmt->claim_oops_do(is_par, cp)) {
3446 tc->do_thread(vmt);
3447 }
3448 }
3449
3450 // The system initialization in the library has three phases.
3451 //
3452 // Phase 1: java.lang.System class initialization
3453 // java.lang.System is a primordial class loaded and initialized
3454 // by the VM early during startup. java.lang.System.<clinit>
3455 // only does registerNatives and keeps the rest of the class
3456 // initialization work later until thread initialization completes.
3457 //
3458 // System.initPhase1 initializes the system properties, the static
3459 // fields in, out, and err. Set up java signal handlers, OS-specific
3460 // system settings, and thread group of the main thread.
3461 static void call_initPhase1(TRAPS) {
3462 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3463 JavaValue result(T_VOID);
3464 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3465 vmSymbols::void_method_signature(), CHECK);
3466 }
3467
3468 // Phase 2. Module system initialization
3469 // This will initialize the module system. Only java.base classes
3470 // can be loaded until phase 2 completes.
3471 //
3472 // Call System.initPhase2 after the compiler initialization and jsr292
3473 // classes get initialized because module initialization runs a lot of java
3474 // code, that for performance reasons, should be compiled. Also, this will
3475 // enable the startup code to use lambda and other language features in this
3476 // phase and onward.
3477 //
3478 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3479 static void call_initPhase2(TRAPS) {
3480 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3481
3482 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3483
3484 JavaValue result(T_INT);
3485 JavaCallArguments args;
3486 args.push_int(DisplayVMOutputToStderr);
3487 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3488 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3489 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3490 if (result.get_jint() != JNI_OK) {
3491 vm_exit_during_initialization(); // no message or exception
3492 }
3493
3494 universe_post_module_init();
3495 }
3496
3497 // Phase 3. final setup - set security manager, system class loader and TCCL
3498 //
3499 // This will instantiate and set the security manager, set the system class
3500 // loader as well as the thread context class loader. The security manager
3501 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3502 // other modules or the application's classpath.
3503 static void call_initPhase3(TRAPS) {
3504 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3505 JavaValue result(T_VOID);
3506 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3507 vmSymbols::void_method_signature(), CHECK);
3508 }
3509
3510 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3511 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3512
3513 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3514 create_vm_init_libraries();
3515 }
3516
3517 initialize_class(vmSymbols::java_lang_String(), CHECK);
3518
3519 // Inject CompactStrings value after the static initializers for String ran.
3520 java_lang_String::set_compact_strings(CompactStrings);
3521
3522 // Initialize java_lang.System (needed before creating the thread)
3523 initialize_class(vmSymbols::java_lang_System(), CHECK);
3524 // The VM creates & returns objects of this class. Make sure it's initialized.
3525 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3526 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3527 Handle thread_group = create_initial_thread_group(CHECK);
3528 Universe::set_main_thread_group(thread_group());
3529 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3530 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3531 main_thread->set_threadObj(thread_object);
3532 // Set thread status to running since main thread has
3533 // been started and running.
3534 java_lang_Thread::set_thread_status(thread_object,
3535 java_lang_Thread::RUNNABLE);
3536
3537 // The VM creates objects of this class.
3538 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3539
3540 // The VM preresolves methods to these classes. Make sure that they get initialized
3541 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3542 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3543
3544 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3545 call_initPhase1(CHECK);
3546
3547 // get the Java runtime name after java.lang.System is initialized
3548 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3549 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3550
3551 // an instance of OutOfMemory exception has been allocated earlier
3552 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3553 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3554 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3555 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3556 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3557 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3558 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3559 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3560 }
3561
3562 void Threads::initialize_jsr292_core_classes(TRAPS) {
3563 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3564
3565 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3566 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3567 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3568 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3569 }
3570
3571 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3572 extern void JDK_Version_init();
3573
3574 // Preinitialize version info.
3575 VM_Version::early_initialize();
3576
3577 // Check version
3578 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3579
3580 // Initialize library-based TLS
3581 ThreadLocalStorage::init();
3582
3583 // Initialize the output stream module
3584 ostream_init();
3585
3586 // Process java launcher properties.
3587 Arguments::process_sun_java_launcher_properties(args);
3588
3589 // Initialize the os module
3590 os::init();
3591
3592 // Record VM creation timing statistics
3593 TraceVmCreationTime create_vm_timer;
3594 create_vm_timer.start();
3595
3596 // Initialize system properties.
3597 Arguments::init_system_properties();
3598
3599 // So that JDK version can be used as a discriminator when parsing arguments
3600 JDK_Version_init();
3601
3602 // Update/Initialize System properties after JDK version number is known
3603 Arguments::init_version_specific_system_properties();
3604
3605 // Make sure to initialize log configuration *before* parsing arguments
3606 LogConfiguration::initialize(create_vm_timer.begin_time());
3607
3608 // Parse arguments
3609 // Note: this internally calls os::init_container_support()
3610 jint parse_result = Arguments::parse(args);
3611 if (parse_result != JNI_OK) return parse_result;
3612
3613 os::init_before_ergo();
3614
3615 jint ergo_result = Arguments::apply_ergo();
3616 if (ergo_result != JNI_OK) return ergo_result;
3617
3618 // Final check of all ranges after ergonomics which may change values.
3619 if (!JVMFlagRangeList::check_ranges()) {
3620 return JNI_EINVAL;
3621 }
3622
3623 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3624 bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo);
3625 if (!constraint_result) {
3626 return JNI_EINVAL;
3627 }
3628
3629 JVMFlagWriteableList::mark_startup();
3630
3631 if (PauseAtStartup) {
3632 os::pause();
3633 }
3634
3635 HOTSPOT_VM_INIT_BEGIN();
3636
3637 // Timing (must come after argument parsing)
3638 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3639
3640 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
3641 // Initialize assert poison page mechanism.
3642 if (ShowRegistersOnAssert) {
3643 initialize_assert_poison();
3644 }
3645 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
3646
3647 // Initialize the os module after parsing the args
3648 jint os_init_2_result = os::init_2();
3649 if (os_init_2_result != JNI_OK) return os_init_2_result;
3650
3651 SafepointMechanism::initialize();
3652
3653 jint adjust_after_os_result = Arguments::adjust_after_os();
3654 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3655
3656 // Initialize output stream logging
3657 ostream_init_log();
3658
3659 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3660 // Must be before create_vm_init_agents()
3661 if (Arguments::init_libraries_at_startup()) {
3662 convert_vm_init_libraries_to_agents();
3663 }
3664
3665 // Launch -agentlib/-agentpath and converted -Xrun agents
3666 if (Arguments::init_agents_at_startup()) {
3667 create_vm_init_agents();
3668 }
3669
3670 // Initialize Threads state
3671 _thread_list = NULL;
3672 _number_of_threads = 0;
3673 _number_of_non_daemon_threads = 0;
3674
3675 // Initialize global data structures and create system classes in heap
3676 vm_init_globals();
3677
3678 #if INCLUDE_JVMCI
3679 if (JVMCICounterSize > 0) {
3680 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3681 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3682 } else {
3683 JavaThread::_jvmci_old_thread_counters = NULL;
3684 }
3685 #endif // INCLUDE_JVMCI
3686
3687 // Attach the main thread to this os thread
3688 JavaThread* main_thread = new JavaThread();
3689 main_thread->set_thread_state(_thread_in_vm);
3690 main_thread->initialize_thread_current();
3691 // must do this before set_active_handles
3692 main_thread->record_stack_base_and_size();
3693 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3694
3695 if (!main_thread->set_as_starting_thread()) {
3696 vm_shutdown_during_initialization(
3697 "Failed necessary internal allocation. Out of swap space");
3698 main_thread->smr_delete();
3699 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3700 return JNI_ENOMEM;
3701 }
3702
3703 // Enable guard page *after* os::create_main_thread(), otherwise it would
3704 // crash Linux VM, see notes in os_linux.cpp.
3705 main_thread->create_stack_guard_pages();
3706
3707 // Initialize Java-Level synchronization subsystem
3708 ObjectMonitor::Initialize();
3709
3710 // Initialize global modules
3711 jint status = init_globals();
3712 if (status != JNI_OK) {
3713 main_thread->smr_delete();
3714 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3715 return status;
3716 }
3717
3718 JFR_ONLY(Jfr::on_vm_init();)
3719
3720 // Should be done after the heap is fully created
3721 main_thread->cache_global_variables();
3722
3723 HandleMark hm;
3724
3725 { MutexLocker mu(Threads_lock);
3726 Threads::add(main_thread);
3727 }
3728
3729 // Any JVMTI raw monitors entered in onload will transition into
3730 // real raw monitor. VM is setup enough here for raw monitor enter.
3731 JvmtiExport::transition_pending_onload_raw_monitors();
3732
3733 // Create the VMThread
3734 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3735
3736 VMThread::create();
3737 Thread* vmthread = VMThread::vm_thread();
3738
3739 if (!os::create_thread(vmthread, os::vm_thread)) {
3740 vm_exit_during_initialization("Cannot create VM thread. "
3741 "Out of system resources.");
3742 }
3743
3744 // Wait for the VM thread to become ready, and VMThread::run to initialize
3745 // Monitors can have spurious returns, must always check another state flag
3746 {
3747 MutexLocker ml(Notify_lock);
3748 os::start_thread(vmthread);
3749 while (vmthread->active_handles() == NULL) {
3750 Notify_lock->wait();
3751 }
3752 }
3753 }
3754
3755 assert(Universe::is_fully_initialized(), "not initialized");
3756 if (VerifyDuringStartup) {
3757 // Make sure we're starting with a clean slate.
3758 VM_Verify verify_op;
3759 VMThread::execute(&verify_op);
3760 }
3761
3762 // We need this to update the java.vm.info property in case any flags used
3763 // to initially define it have been changed. This is needed for both CDS and
3764 // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info
3765 // is initially computed. See Abstract_VM_Version::vm_info_string().
3766 // This update must happen before we initialize the java classes, but
3767 // after any initialization logic that might modify the flags.
3768 Arguments::update_vm_info_property(VM_Version::vm_info_string());
3769
3770 Thread* THREAD = Thread::current();
3771
3772 // Always call even when there are not JVMTI environments yet, since environments
3773 // may be attached late and JVMTI must track phases of VM execution
3774 JvmtiExport::enter_early_start_phase();
3775
3776 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3777 JvmtiExport::post_early_vm_start();
3778
3779 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3780
3781 quicken_jni_functions();
3782
3783 // No more stub generation allowed after that point.
3784 StubCodeDesc::freeze();
3785
3786 // Set flag that basic initialization has completed. Used by exceptions and various
3787 // debug stuff, that does not work until all basic classes have been initialized.
3788 set_init_completed();
3789
3790 LogConfiguration::post_initialize();
3791 Metaspace::post_initialize();
3792
3793 HOTSPOT_VM_INIT_END();
3794
3795 // record VM initialization completion time
3796 #if INCLUDE_MANAGEMENT
3797 Management::record_vm_init_completed();
3798 #endif // INCLUDE_MANAGEMENT
3799
3800 // Signal Dispatcher needs to be started before VMInit event is posted
3801 os::initialize_jdk_signal_support(CHECK_JNI_ERR);
3802
3803 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3804 if (!DisableAttachMechanism) {
3805 AttachListener::vm_start();
3806 if (StartAttachListener || AttachListener::init_at_startup()) {
3807 AttachListener::init();
3808 }
3809 }
3810
3811 // Launch -Xrun agents
3812 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3813 // back-end can launch with -Xdebug -Xrunjdwp.
3814 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3815 create_vm_init_libraries();
3816 }
3817
3818 if (CleanChunkPoolAsync) {
3819 Chunk::start_chunk_pool_cleaner_task();
3820 }
3821
3822 // initialize compiler(s)
3823 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3824 #if INCLUDE_JVMCI
3825 bool force_JVMCI_intialization = false;
3826 if (EnableJVMCI) {
3827 // Initialize JVMCI eagerly when it is explicitly requested.
3828 // Or when JVMCIPrintProperties is enabled.
3829 // The JVMCI Java initialization code will read this flag and
3830 // do the printing if it's set.
3831 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties;
3832
3833 if (!force_JVMCI_intialization) {
3834 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
3835 // compilations via JVMCI will not actually block until JVMCI is initialized.
3836 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
3837 }
3838 }
3839 #endif
3840 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
3841 // Postpone completion of compiler initialization to after JVMCI
3842 // is initialized to avoid timeouts of blocking compilations.
3843 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
3844 CompileBroker::compilation_init_phase2();
3845 }
3846 #endif
3847
3848 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3849 // It is done after compilers are initialized, because otherwise compilations of
3850 // signature polymorphic MH intrinsics can be missed
3851 // (see SystemDictionary::find_method_handle_intrinsic).
3852 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3853
3854 // This will initialize the module system. Only java.base classes can be
3855 // loaded until phase 2 completes
3856 call_initPhase2(CHECK_JNI_ERR);
3857
3858 // Always call even when there are not JVMTI environments yet, since environments
3859 // may be attached late and JVMTI must track phases of VM execution
3860 JvmtiExport::enter_start_phase();
3861
3862 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3863 JvmtiExport::post_vm_start();
3864
3865 // Final system initialization including security manager and system class loader
3866 call_initPhase3(CHECK_JNI_ERR);
3867
3868 // cache the system and platform class loaders
3869 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
3870
3871 #if INCLUDE_CDS
3872 if (DumpSharedSpaces) {
3873 // capture the module path info from the ModuleEntryTable
3874 ClassLoader::initialize_module_path(THREAD);
3875 }
3876 #endif
3877
3878 #if INCLUDE_JVMCI
3879 if (force_JVMCI_intialization) {
3880 JVMCIRuntime::force_initialization(CHECK_JNI_ERR);
3881 CompileBroker::compilation_init_phase2();
3882 }
3883 #endif
3884
3885 // Always call even when there are not JVMTI environments yet, since environments
3886 // may be attached late and JVMTI must track phases of VM execution
3887 JvmtiExport::enter_live_phase();
3888
3889 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3890 JvmtiExport::post_vm_initialized();
3891
3892 JFR_ONLY(Jfr::on_vm_start();)
3893
3894 #if INCLUDE_MANAGEMENT
3895 Management::initialize(THREAD);
3896
3897 if (HAS_PENDING_EXCEPTION) {
3898 // management agent fails to start possibly due to
3899 // configuration problem and is responsible for printing
3900 // stack trace if appropriate. Simply exit VM.
3901 vm_exit(1);
3902 }
3903 #endif // INCLUDE_MANAGEMENT
3904
3905 if (MemProfiling) MemProfiler::engage();
3906 StatSampler::engage();
3907 if (CheckJNICalls) JniPeriodicChecker::engage();
3908
3909 BiasedLocking::init();
3910
3911 #if INCLUDE_RTM_OPT
3912 RTMLockingCounters::init();
3913 #endif
3914
3915 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3916 call_postVMInitHook(THREAD);
3917 // The Java side of PostVMInitHook.run must deal with all
3918 // exceptions and provide means of diagnosis.
3919 if (HAS_PENDING_EXCEPTION) {
3920 CLEAR_PENDING_EXCEPTION;
3921 }
3922 }
3923
3924 {
3925 MutexLocker ml(PeriodicTask_lock);
3926 // Make sure the WatcherThread can be started by WatcherThread::start()
3927 // or by dynamic enrollment.
3928 WatcherThread::make_startable();
3929 // Start up the WatcherThread if there are any periodic tasks
3930 // NOTE: All PeriodicTasks should be registered by now. If they
3931 // aren't, late joiners might appear to start slowly (we might
3932 // take a while to process their first tick).
3933 if (PeriodicTask::num_tasks() > 0) {
3934 WatcherThread::start();
3935 }
3936 }
3937
3938 create_vm_timer.end();
3939 #ifdef ASSERT
3940 _vm_complete = true;
3941 #endif
3942
3943 if (DumpSharedSpaces) {
3944 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3945 ShouldNotReachHere();
3946 }
3947
3948 return JNI_OK;
3949 }
3950
3951 // type for the Agent_OnLoad and JVM_OnLoad entry points
3952 extern "C" {
3953 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3954 }
3955 // Find a command line agent library and return its entry point for
3956 // -agentlib: -agentpath: -Xrun
3957 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3958 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3959 const char *on_load_symbols[],
3960 size_t num_symbol_entries) {
3961 OnLoadEntry_t on_load_entry = NULL;
3962 void *library = NULL;
3963
3964 if (!agent->valid()) {
3965 char buffer[JVM_MAXPATHLEN];
3966 char ebuf[1024] = "";
3967 const char *name = agent->name();
3968 const char *msg = "Could not find agent library ";
3969
3970 // First check to see if agent is statically linked into executable
3971 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3972 library = agent->os_lib();
3973 } else if (agent->is_absolute_path()) {
3974 library = os::dll_load(name, ebuf, sizeof ebuf);
3975 if (library == NULL) {
3976 const char *sub_msg = " in absolute path, with error: ";
3977 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3978 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3979 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3980 // If we can't find the agent, exit.
3981 vm_exit_during_initialization(buf, NULL);
3982 FREE_C_HEAP_ARRAY(char, buf);
3983 }
3984 } else {
3985 // Try to load the agent from the standard dll directory
3986 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3987 name)) {
3988 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3989 }
3990 if (library == NULL) { // Try the library path directory.
3991 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
3992 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3993 }
3994 if (library == NULL) {
3995 const char *sub_msg = " on the library path, with error: ";
3996 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
3997
3998 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
3999 strlen(ebuf) + strlen(sub_msg2) + 1;
4000 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4001 if (!agent->is_instrument_lib()) {
4002 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4003 } else {
4004 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4005 }
4006 // If we can't find the agent, exit.
4007 vm_exit_during_initialization(buf, NULL);
4008 FREE_C_HEAP_ARRAY(char, buf);
4009 }
4010 }
4011 }
4012 agent->set_os_lib(library);
4013 agent->set_valid();
4014 }
4015
4016 // Find the OnLoad function.
4017 on_load_entry =
4018 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4019 false,
4020 on_load_symbols,
4021 num_symbol_entries));
4022 return on_load_entry;
4023 }
4024
4025 // Find the JVM_OnLoad entry point
4026 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4027 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4028 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4029 }
4030
4031 // Find the Agent_OnLoad entry point
4032 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4033 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4034 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4035 }
4036
4037 // For backwards compatibility with -Xrun
4038 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4039 // treated like -agentpath:
4040 // Must be called before agent libraries are created
4041 void Threads::convert_vm_init_libraries_to_agents() {
4042 AgentLibrary* agent;
4043 AgentLibrary* next;
4044
4045 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4046 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4047 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4048
4049 // If there is an JVM_OnLoad function it will get called later,
4050 // otherwise see if there is an Agent_OnLoad
4051 if (on_load_entry == NULL) {
4052 on_load_entry = lookup_agent_on_load(agent);
4053 if (on_load_entry != NULL) {
4054 // switch it to the agent list -- so that Agent_OnLoad will be called,
4055 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4056 Arguments::convert_library_to_agent(agent);
4057 } else {
4058 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4059 }
4060 }
4061 }
4062 }
4063
4064 // Create agents for -agentlib: -agentpath: and converted -Xrun
4065 // Invokes Agent_OnLoad
4066 // Called very early -- before JavaThreads exist
4067 void Threads::create_vm_init_agents() {
4068 extern struct JavaVM_ main_vm;
4069 AgentLibrary* agent;
4070
4071 JvmtiExport::enter_onload_phase();
4072
4073 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4074 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4075
4076 if (on_load_entry != NULL) {
4077 // Invoke the Agent_OnLoad function
4078 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4079 if (err != JNI_OK) {
4080 vm_exit_during_initialization("agent library failed to init", agent->name());
4081 }
4082 } else {
4083 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4084 }
4085 }
4086 JvmtiExport::enter_primordial_phase();
4087 }
4088
4089 extern "C" {
4090 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4091 }
4092
4093 void Threads::shutdown_vm_agents() {
4094 // Send any Agent_OnUnload notifications
4095 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4096 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4097 extern struct JavaVM_ main_vm;
4098 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4099
4100 // Find the Agent_OnUnload function.
4101 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4102 os::find_agent_function(agent,
4103 false,
4104 on_unload_symbols,
4105 num_symbol_entries));
4106
4107 // Invoke the Agent_OnUnload function
4108 if (unload_entry != NULL) {
4109 JavaThread* thread = JavaThread::current();
4110 ThreadToNativeFromVM ttn(thread);
4111 HandleMark hm(thread);
4112 (*unload_entry)(&main_vm);
4113 }
4114 }
4115 }
4116
4117 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4118 // Invokes JVM_OnLoad
4119 void Threads::create_vm_init_libraries() {
4120 extern struct JavaVM_ main_vm;
4121 AgentLibrary* agent;
4122
4123 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4124 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4125
4126 if (on_load_entry != NULL) {
4127 // Invoke the JVM_OnLoad function
4128 JavaThread* thread = JavaThread::current();
4129 ThreadToNativeFromVM ttn(thread);
4130 HandleMark hm(thread);
4131 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4132 if (err != JNI_OK) {
4133 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4134 }
4135 } else {
4136 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4137 }
4138 }
4139 }
4140
4141
4142 // Last thread running calls java.lang.Shutdown.shutdown()
4143 void JavaThread::invoke_shutdown_hooks() {
4144 HandleMark hm(this);
4145
4146 // We could get here with a pending exception, if so clear it now.
4147 if (this->has_pending_exception()) {
4148 this->clear_pending_exception();
4149 }
4150
4151 EXCEPTION_MARK;
4152 Klass* shutdown_klass =
4153 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4154 THREAD);
4155 if (shutdown_klass != NULL) {
4156 // SystemDictionary::resolve_or_null will return null if there was
4157 // an exception. If we cannot load the Shutdown class, just don't
4158 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4159 // won't be run. Note that if a shutdown hook was registered,
4160 // the Shutdown class would have already been loaded
4161 // (Runtime.addShutdownHook will load it).
4162 JavaValue result(T_VOID);
4163 JavaCalls::call_static(&result,
4164 shutdown_klass,
4165 vmSymbols::shutdown_method_name(),
4166 vmSymbols::void_method_signature(),
4167 THREAD);
4168 }
4169 CLEAR_PENDING_EXCEPTION;
4170 }
4171
4172 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4173 // the program falls off the end of main(). Another VM exit path is through
4174 // vm_exit() when the program calls System.exit() to return a value or when
4175 // there is a serious error in VM. The two shutdown paths are not exactly
4176 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4177 // and VM_Exit op at VM level.
4178 //
4179 // Shutdown sequence:
4180 // + Shutdown native memory tracking if it is on
4181 // + Wait until we are the last non-daemon thread to execute
4182 // <-- every thing is still working at this moment -->
4183 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4184 // shutdown hooks
4185 // + Call before_exit(), prepare for VM exit
4186 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4187 // currently the only user of this mechanism is File.deleteOnExit())
4188 // > stop StatSampler, watcher thread, CMS threads,
4189 // post thread end and vm death events to JVMTI,
4190 // stop signal thread
4191 // + Call JavaThread::exit(), it will:
4192 // > release JNI handle blocks, remove stack guard pages
4193 // > remove this thread from Threads list
4194 // <-- no more Java code from this thread after this point -->
4195 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4196 // the compiler threads at safepoint
4197 // <-- do not use anything that could get blocked by Safepoint -->
4198 // + Disable tracing at JNI/JVM barriers
4199 // + Set _vm_exited flag for threads that are still running native code
4200 // + Delete this thread
4201 // + Call exit_globals()
4202 // > deletes tty
4203 // > deletes PerfMemory resources
4204 // + Return to caller
4205
4206 bool Threads::destroy_vm() {
4207 JavaThread* thread = JavaThread::current();
4208
4209 #ifdef ASSERT
4210 _vm_complete = false;
4211 #endif
4212 // Wait until we are the last non-daemon thread to execute
4213 { MutexLocker nu(Threads_lock);
4214 while (Threads::number_of_non_daemon_threads() > 1)
4215 // This wait should make safepoint checks, wait without a timeout,
4216 // and wait as a suspend-equivalent condition.
4217 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4218 Mutex::_as_suspend_equivalent_flag);
4219 }
4220
4221 EventShutdown e;
4222 if (e.should_commit()) {
4223 e.set_reason("No remaining non-daemon Java threads");
4224 e.commit();
4225 }
4226
4227 // Hang forever on exit if we are reporting an error.
4228 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4229 os::infinite_sleep();
4230 }
4231 os::wait_for_keypress_at_exit();
4232
4233 // run Java level shutdown hooks
4234 thread->invoke_shutdown_hooks();
4235
4236 before_exit(thread);
4237
4238 thread->exit(true);
4239 // thread will never call smr_delete, instead of implicit cancel
4240 // in wait_for_vm_thread_exit we do it explicit.
4241 thread->cancel_handshake();
4242
4243 // Stop VM thread.
4244 {
4245 // 4945125 The vm thread comes to a safepoint during exit.
4246 // GC vm_operations can get caught at the safepoint, and the
4247 // heap is unparseable if they are caught. Grab the Heap_lock
4248 // to prevent this. The GC vm_operations will not be able to
4249 // queue until after the vm thread is dead. After this point,
4250 // we'll never emerge out of the safepoint before the VM exits.
4251
4252 MutexLocker ml(Heap_lock);
4253
4254 VMThread::wait_for_vm_thread_exit();
4255 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4256 VMThread::destroy();
4257 }
4258
4259 // Now, all Java threads are gone except daemon threads. Daemon threads
4260 // running Java code or in VM are stopped by the Safepoint. However,
4261 // daemon threads executing native code are still running. But they
4262 // will be stopped at native=>Java/VM barriers. Note that we can't
4263 // simply kill or suspend them, as it is inherently deadlock-prone.
4264
4265 VM_Exit::set_vm_exited();
4266
4267 // Clean up ideal graph printers after the VMThread has started
4268 // the final safepoint which will block all the Compiler threads.
4269 // Note that this Thread has already logically exited so the
4270 // clean_up() function's use of a JavaThreadIteratorWithHandle
4271 // would be a problem except set_vm_exited() has remembered the
4272 // shutdown thread which is granted a policy exception.
4273 #if defined(COMPILER2) && !defined(PRODUCT)
4274 IdealGraphPrinter::clean_up();
4275 #endif
4276
4277 notify_vm_shutdown();
4278
4279 // We are after VM_Exit::set_vm_exited() so we can't call
4280 // thread->smr_delete() or we will block on the Threads_lock.
4281 // Deleting the shutdown thread here is safe because another
4282 // JavaThread cannot have an active ThreadsListHandle for
4283 // this JavaThread.
4284 delete thread;
4285
4286 #if INCLUDE_JVMCI
4287 if (JVMCICounterSize > 0) {
4288 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4289 }
4290 #endif
4291
4292 // exit_globals() will delete tty
4293 exit_globals();
4294
4295 LogConfiguration::finalize();
4296
4297 return true;
4298 }
4299
4300
4301 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4302 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4303 return is_supported_jni_version(version);
4304 }
4305
4306
4307 jboolean Threads::is_supported_jni_version(jint version) {
4308 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4309 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4310 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4311 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4312 if (version == JNI_VERSION_9) return JNI_TRUE;
4313 if (version == JNI_VERSION_10) return JNI_TRUE;
4314 return JNI_FALSE;
4315 }
4316
4317
4318 void Threads::add(JavaThread* p, bool force_daemon) {
4319 // The threads lock must be owned at this point
4320 assert_locked_or_safepoint(Threads_lock);
4321
4322 BarrierSet::barrier_set()->on_thread_attach(p);
4323
4324 p->set_next(_thread_list);
4325 _thread_list = p;
4326
4327 // Once a JavaThread is added to the Threads list, smr_delete() has
4328 // to be used to delete it. Otherwise we can just delete it directly.
4329 p->set_on_thread_list();
4330
4331 _number_of_threads++;
4332 oop threadObj = p->threadObj();
4333 bool daemon = true;
4334 // Bootstrapping problem: threadObj can be null for initial
4335 // JavaThread (or for threads attached via JNI)
4336 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4337 _number_of_non_daemon_threads++;
4338 daemon = false;
4339 }
4340
4341 ThreadService::add_thread(p, daemon);
4342
4343 // Maintain fast thread list
4344 ThreadsSMRSupport::add_thread(p);
4345
4346 // Possible GC point.
4347 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4348 }
4349
4350 void Threads::remove(JavaThread* p) {
4351
4352 // Reclaim the objectmonitors from the omInUseList and omFreeList of the moribund thread.
4353 ObjectSynchronizer::omFlush(p);
4354
4355 // Extra scope needed for Thread_lock, so we can check
4356 // that we do not remove thread without safepoint code notice
4357 { MutexLocker ml(Threads_lock);
4358
4359 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4360
4361 // Maintain fast thread list
4362 ThreadsSMRSupport::remove_thread(p);
4363
4364 JavaThread* current = _thread_list;
4365 JavaThread* prev = NULL;
4366
4367 while (current != p) {
4368 prev = current;
4369 current = current->next();
4370 }
4371
4372 if (prev) {
4373 prev->set_next(current->next());
4374 } else {
4375 _thread_list = p->next();
4376 }
4377
4378 _number_of_threads--;
4379 oop threadObj = p->threadObj();
4380 bool daemon = true;
4381 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4382 _number_of_non_daemon_threads--;
4383 daemon = false;
4384
4385 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4386 // on destroy_vm will wake up.
4387 if (number_of_non_daemon_threads() == 1) {
4388 Threads_lock->notify_all();
4389 }
4390 }
4391 ThreadService::remove_thread(p, daemon);
4392
4393 // Make sure that safepoint code disregard this thread. This is needed since
4394 // the thread might mess around with locks after this point. This can cause it
4395 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4396 // of this thread since it is removed from the queue.
4397 p->set_terminated_value();
4398 } // unlock Threads_lock
4399
4400 // Since Events::log uses a lock, we grab it outside the Threads_lock
4401 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4402 }
4403
4404 // Operations on the Threads list for GC. These are not explicitly locked,
4405 // but the garbage collector must provide a safe context for them to run.
4406 // In particular, these things should never be called when the Threads_lock
4407 // is held by some other thread. (Note: the Safepoint abstraction also
4408 // uses the Threads_lock to guarantee this property. It also makes sure that
4409 // all threads gets blocked when exiting or starting).
4410
4411 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4412 ALL_JAVA_THREADS(p) {
4413 p->oops_do(f, cf);
4414 }
4415 VMThread::vm_thread()->oops_do(f, cf);
4416 }
4417
4418 void Threads::change_thread_claim_parity() {
4419 // Set the new claim parity.
4420 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4421 "Not in range.");
4422 _thread_claim_parity++;
4423 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4424 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4425 "Not in range.");
4426 }
4427
4428 #ifdef ASSERT
4429 void Threads::assert_all_threads_claimed() {
4430 ALL_JAVA_THREADS(p) {
4431 const int thread_parity = p->oops_do_parity();
4432 assert((thread_parity == _thread_claim_parity),
4433 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4434 }
4435 VMThread* vmt = VMThread::vm_thread();
4436 const int thread_parity = vmt->oops_do_parity();
4437 assert((thread_parity == _thread_claim_parity),
4438 "VMThread " PTR_FORMAT " has incorrect parity %d != %d", p2i(vmt), thread_parity, _thread_claim_parity);
4439 }
4440 #endif // ASSERT
4441
4442 class ParallelOopsDoThreadClosure : public ThreadClosure {
4443 private:
4444 OopClosure* _f;
4445 CodeBlobClosure* _cf;
4446 public:
4447 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4448 void do_thread(Thread* t) {
4449 t->oops_do(_f, _cf);
4450 }
4451 };
4452
4453 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4454 ParallelOopsDoThreadClosure tc(f, cf);
4455 possibly_parallel_threads_do(is_par, &tc);
4456 }
4457
4458 void Threads::nmethods_do(CodeBlobClosure* cf) {
4459 ALL_JAVA_THREADS(p) {
4460 // This is used by the code cache sweeper to mark nmethods that are active
4461 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4462 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4463 if(!p->is_Code_cache_sweeper_thread()) {
4464 p->nmethods_do(cf);
4465 }
4466 }
4467 }
4468
4469 void Threads::metadata_do(void f(Metadata*)) {
4470 ALL_JAVA_THREADS(p) {
4471 p->metadata_do(f);
4472 }
4473 }
4474
4475 class ThreadHandlesClosure : public ThreadClosure {
4476 void (*_f)(Metadata*);
4477 public:
4478 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4479 virtual void do_thread(Thread* thread) {
4480 thread->metadata_handles_do(_f);
4481 }
4482 };
4483
4484 void Threads::metadata_handles_do(void f(Metadata*)) {
4485 // Only walk the Handles in Thread.
4486 ThreadHandlesClosure handles_closure(f);
4487 threads_do(&handles_closure);
4488 }
4489
4490 void Threads::deoptimized_wrt_marked_nmethods() {
4491 ALL_JAVA_THREADS(p) {
4492 p->deoptimized_wrt_marked_nmethods();
4493 }
4494 }
4495
4496
4497 // Get count Java threads that are waiting to enter the specified monitor.
4498 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4499 int count,
4500 address monitor) {
4501 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4502
4503 int i = 0;
4504 DO_JAVA_THREADS(t_list, p) {
4505 if (!p->can_call_java()) continue;
4506
4507 address pending = (address)p->current_pending_monitor();
4508 if (pending == monitor) { // found a match
4509 if (i < count) result->append(p); // save the first count matches
4510 i++;
4511 }
4512 }
4513
4514 return result;
4515 }
4516
4517
4518 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4519 address owner) {
4520 // NULL owner means not locked so we can skip the search
4521 if (owner == NULL) return NULL;
4522
4523 DO_JAVA_THREADS(t_list, p) {
4524 // first, see if owner is the address of a Java thread
4525 if (owner == (address)p) return p;
4526 }
4527
4528 // Cannot assert on lack of success here since this function may be
4529 // used by code that is trying to report useful problem information
4530 // like deadlock detection.
4531 if (UseHeavyMonitors) return NULL;
4532
4533 // If we didn't find a matching Java thread and we didn't force use of
4534 // heavyweight monitors, then the owner is the stack address of the
4535 // Lock Word in the owning Java thread's stack.
4536 //
4537 JavaThread* the_owner = NULL;
4538 DO_JAVA_THREADS(t_list, q) {
4539 if (q->is_lock_owned(owner)) {
4540 the_owner = q;
4541 break;
4542 }
4543 }
4544
4545 // cannot assert on lack of success here; see above comment
4546 return the_owner;
4547 }
4548
4549 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4550 void Threads::print_on(outputStream* st, bool print_stacks,
4551 bool internal_format, bool print_concurrent_locks,
4552 bool print_extended_info) {
4553 char buf[32];
4554 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4555
4556 st->print_cr("Full thread dump %s (%s %s):",
4557 Abstract_VM_Version::vm_name(),
4558 Abstract_VM_Version::vm_release(),
4559 Abstract_VM_Version::vm_info_string());
4560 st->cr();
4561
4562 #if INCLUDE_SERVICES
4563 // Dump concurrent locks
4564 ConcurrentLocksDump concurrent_locks;
4565 if (print_concurrent_locks) {
4566 concurrent_locks.dump_at_safepoint();
4567 }
4568 #endif // INCLUDE_SERVICES
4569
4570 ThreadsSMRSupport::print_info_on(st);
4571 st->cr();
4572
4573 ALL_JAVA_THREADS(p) {
4574 ResourceMark rm;
4575 p->print_on(st, print_extended_info);
4576 if (print_stacks) {
4577 if (internal_format) {
4578 p->trace_stack();
4579 } else {
4580 p->print_stack_on(st);
4581 }
4582 }
4583 st->cr();
4584 #if INCLUDE_SERVICES
4585 if (print_concurrent_locks) {
4586 concurrent_locks.print_locks_on(p, st);
4587 }
4588 #endif // INCLUDE_SERVICES
4589 }
4590
4591 VMThread::vm_thread()->print_on(st);
4592 st->cr();
4593 Universe::heap()->print_gc_threads_on(st);
4594 WatcherThread* wt = WatcherThread::watcher_thread();
4595 if (wt != NULL) {
4596 wt->print_on(st);
4597 st->cr();
4598 }
4599
4600 st->flush();
4601 }
4602
4603 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4604 int buflen, bool* found_current) {
4605 if (this_thread != NULL) {
4606 bool is_current = (current == this_thread);
4607 *found_current = *found_current || is_current;
4608 st->print("%s", is_current ? "=>" : " ");
4609
4610 st->print(PTR_FORMAT, p2i(this_thread));
4611 st->print(" ");
4612 this_thread->print_on_error(st, buf, buflen);
4613 st->cr();
4614 }
4615 }
4616
4617 class PrintOnErrorClosure : public ThreadClosure {
4618 outputStream* _st;
4619 Thread* _current;
4620 char* _buf;
4621 int _buflen;
4622 bool* _found_current;
4623 public:
4624 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4625 int buflen, bool* found_current) :
4626 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4627
4628 virtual void do_thread(Thread* thread) {
4629 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4630 }
4631 };
4632
4633 // Threads::print_on_error() is called by fatal error handler. It's possible
4634 // that VM is not at safepoint and/or current thread is inside signal handler.
4635 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4636 // memory (even in resource area), it might deadlock the error handler.
4637 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4638 int buflen) {
4639 ThreadsSMRSupport::print_info_on(st);
4640 st->cr();
4641
4642 bool found_current = false;
4643 st->print_cr("Java Threads: ( => current thread )");
4644 ALL_JAVA_THREADS(thread) {
4645 print_on_error(thread, st, current, buf, buflen, &found_current);
4646 }
4647 st->cr();
4648
4649 st->print_cr("Other Threads:");
4650 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4651 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4652
4653 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4654 Universe::heap()->gc_threads_do(&print_closure);
4655
4656 if (!found_current) {
4657 st->cr();
4658 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4659 current->print_on_error(st, buf, buflen);
4660 st->cr();
4661 }
4662 st->cr();
4663
4664 st->print_cr("Threads with active compile tasks:");
4665 print_threads_compiling(st, buf, buflen);
4666 }
4667
4668 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) {
4669 ALL_JAVA_THREADS(thread) {
4670 if (thread->is_Compiler_thread()) {
4671 CompilerThread* ct = (CompilerThread*) thread;
4672
4673 // Keep task in local variable for NULL check.
4674 // ct->_task might be set to NULL by concurring compiler thread
4675 // because it completed the compilation. The task is never freed,
4676 // though, just returned to a free list.
4677 CompileTask* task = ct->task();
4678 if (task != NULL) {
4679 thread->print_name_on_error(st, buf, buflen);
4680 task->print(st, NULL, true, true);
4681 }
4682 }
4683 }
4684 }
4685
4686
4687 // Internal SpinLock and Mutex
4688 // Based on ParkEvent
4689
4690 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4691 //
4692 // We employ SpinLocks _only for low-contention, fixed-length
4693 // short-duration critical sections where we're concerned
4694 // about native mutex_t or HotSpot Mutex:: latency.
4695 // The mux construct provides a spin-then-block mutual exclusion
4696 // mechanism.
4697 //
4698 // Testing has shown that contention on the ListLock guarding gFreeList
4699 // is common. If we implement ListLock as a simple SpinLock it's common
4700 // for the JVM to devolve to yielding with little progress. This is true
4701 // despite the fact that the critical sections protected by ListLock are
4702 // extremely short.
4703 //
4704 // TODO-FIXME: ListLock should be of type SpinLock.
4705 // We should make this a 1st-class type, integrated into the lock
4706 // hierarchy as leaf-locks. Critically, the SpinLock structure
4707 // should have sufficient padding to avoid false-sharing and excessive
4708 // cache-coherency traffic.
4709
4710
4711 typedef volatile int SpinLockT;
4712
4713 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4714 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4715 return; // normal fast-path return
4716 }
4717
4718 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4719 TEVENT(SpinAcquire - ctx);
4720 int ctr = 0;
4721 int Yields = 0;
4722 for (;;) {
4723 while (*adr != 0) {
4724 ++ctr;
4725 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4726 if (Yields > 5) {
4727 os::naked_short_sleep(1);
4728 } else {
4729 os::naked_yield();
4730 ++Yields;
4731 }
4732 } else {
4733 SpinPause();
4734 }
4735 }
4736 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4737 }
4738 }
4739
4740 void Thread::SpinRelease(volatile int * adr) {
4741 assert(*adr != 0, "invariant");
4742 OrderAccess::fence(); // guarantee at least release consistency.
4743 // Roach-motel semantics.
4744 // It's safe if subsequent LDs and STs float "up" into the critical section,
4745 // but prior LDs and STs within the critical section can't be allowed
4746 // to reorder or float past the ST that releases the lock.
4747 // Loads and stores in the critical section - which appear in program
4748 // order before the store that releases the lock - must also appear
4749 // before the store that releases the lock in memory visibility order.
4750 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4751 // the ST of 0 into the lock-word which releases the lock, so fence
4752 // more than covers this on all platforms.
4753 *adr = 0;
4754 }
4755
4756 // muxAcquire and muxRelease:
4757 //
4758 // * muxAcquire and muxRelease support a single-word lock-word construct.
4759 // The LSB of the word is set IFF the lock is held.
4760 // The remainder of the word points to the head of a singly-linked list
4761 // of threads blocked on the lock.
4762 //
4763 // * The current implementation of muxAcquire-muxRelease uses its own
4764 // dedicated Thread._MuxEvent instance. If we're interested in
4765 // minimizing the peak number of extant ParkEvent instances then
4766 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4767 // as certain invariants were satisfied. Specifically, care would need
4768 // to be taken with regards to consuming unpark() "permits".
4769 // A safe rule of thumb is that a thread would never call muxAcquire()
4770 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4771 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4772 // consume an unpark() permit intended for monitorenter, for instance.
4773 // One way around this would be to widen the restricted-range semaphore
4774 // implemented in park(). Another alternative would be to provide
4775 // multiple instances of the PlatformEvent() for each thread. One
4776 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4777 //
4778 // * Usage:
4779 // -- Only as leaf locks
4780 // -- for short-term locking only as muxAcquire does not perform
4781 // thread state transitions.
4782 //
4783 // Alternatives:
4784 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4785 // but with parking or spin-then-park instead of pure spinning.
4786 // * Use Taura-Oyama-Yonenzawa locks.
4787 // * It's possible to construct a 1-0 lock if we encode the lockword as
4788 // (List,LockByte). Acquire will CAS the full lockword while Release
4789 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4790 // acquiring threads use timers (ParkTimed) to detect and recover from
4791 // the stranding window. Thread/Node structures must be aligned on 256-byte
4792 // boundaries by using placement-new.
4793 // * Augment MCS with advisory back-link fields maintained with CAS().
4794 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4795 // The validity of the backlinks must be ratified before we trust the value.
4796 // If the backlinks are invalid the exiting thread must back-track through the
4797 // the forward links, which are always trustworthy.
4798 // * Add a successor indication. The LockWord is currently encoded as
4799 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4800 // to provide the usual futile-wakeup optimization.
4801 // See RTStt for details.
4802 // * Consider schedctl.sc_nopreempt to cover the critical section.
4803 //
4804
4805
4806 const intptr_t LOCKBIT = 1;
4807
4808 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4809 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4810 if (w == 0) return;
4811 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4812 return;
4813 }
4814
4815 TEVENT(muxAcquire - Contention);
4816 ParkEvent * const Self = Thread::current()->_MuxEvent;
4817 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4818 for (;;) {
4819 int its = (os::is_MP() ? 100 : 0) + 1;
4820
4821 // Optional spin phase: spin-then-park strategy
4822 while (--its >= 0) {
4823 w = *Lock;
4824 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4825 return;
4826 }
4827 }
4828
4829 Self->reset();
4830 Self->OnList = intptr_t(Lock);
4831 // The following fence() isn't _strictly necessary as the subsequent
4832 // CAS() both serializes execution and ratifies the fetched *Lock value.
4833 OrderAccess::fence();
4834 for (;;) {
4835 w = *Lock;
4836 if ((w & LOCKBIT) == 0) {
4837 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4838 Self->OnList = 0; // hygiene - allows stronger asserts
4839 return;
4840 }
4841 continue; // Interference -- *Lock changed -- Just retry
4842 }
4843 assert(w & LOCKBIT, "invariant");
4844 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4845 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4846 }
4847
4848 while (Self->OnList != 0) {
4849 Self->park();
4850 }
4851 }
4852 }
4853
4854 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4855 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4856 if (w == 0) return;
4857 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4858 return;
4859 }
4860
4861 TEVENT(muxAcquire - Contention);
4862 ParkEvent * ReleaseAfter = NULL;
4863 if (ev == NULL) {
4864 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4865 }
4866 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4867 for (;;) {
4868 guarantee(ev->OnList == 0, "invariant");
4869 int its = (os::is_MP() ? 100 : 0) + 1;
4870
4871 // Optional spin phase: spin-then-park strategy
4872 while (--its >= 0) {
4873 w = *Lock;
4874 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4875 if (ReleaseAfter != NULL) {
4876 ParkEvent::Release(ReleaseAfter);
4877 }
4878 return;
4879 }
4880 }
4881
4882 ev->reset();
4883 ev->OnList = intptr_t(Lock);
4884 // The following fence() isn't _strictly necessary as the subsequent
4885 // CAS() both serializes execution and ratifies the fetched *Lock value.
4886 OrderAccess::fence();
4887 for (;;) {
4888 w = *Lock;
4889 if ((w & LOCKBIT) == 0) {
4890 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4891 ev->OnList = 0;
4892 // We call ::Release while holding the outer lock, thus
4893 // artificially lengthening the critical section.
4894 // Consider deferring the ::Release() until the subsequent unlock(),
4895 // after we've dropped the outer lock.
4896 if (ReleaseAfter != NULL) {
4897 ParkEvent::Release(ReleaseAfter);
4898 }
4899 return;
4900 }
4901 continue; // Interference -- *Lock changed -- Just retry
4902 }
4903 assert(w & LOCKBIT, "invariant");
4904 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4905 if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4906 }
4907
4908 while (ev->OnList != 0) {
4909 ev->park();
4910 }
4911 }
4912 }
4913
4914 // Release() must extract a successor from the list and then wake that thread.
4915 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4916 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4917 // Release() would :
4918 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4919 // (B) Extract a successor from the private list "in-hand"
4920 // (C) attempt to CAS() the residual back into *Lock over null.
4921 // If there were any newly arrived threads and the CAS() would fail.
4922 // In that case Release() would detach the RATs, re-merge the list in-hand
4923 // with the RATs and repeat as needed. Alternately, Release() might
4924 // detach and extract a successor, but then pass the residual list to the wakee.
4925 // The wakee would be responsible for reattaching and remerging before it
4926 // competed for the lock.
4927 //
4928 // Both "pop" and DMR are immune from ABA corruption -- there can be
4929 // multiple concurrent pushers, but only one popper or detacher.
4930 // This implementation pops from the head of the list. This is unfair,
4931 // but tends to provide excellent throughput as hot threads remain hot.
4932 // (We wake recently run threads first).
4933 //
4934 // All paths through muxRelease() will execute a CAS.
4935 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4936 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4937 // executed within the critical section are complete and globally visible before the
4938 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4939 void Thread::muxRelease(volatile intptr_t * Lock) {
4940 for (;;) {
4941 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
4942 assert(w & LOCKBIT, "invariant");
4943 if (w == LOCKBIT) return;
4944 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4945 assert(List != NULL, "invariant");
4946 assert(List->OnList == intptr_t(Lock), "invariant");
4947 ParkEvent * const nxt = List->ListNext;
4948 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4949
4950 // The following CAS() releases the lock and pops the head element.
4951 // The CAS() also ratifies the previously fetched lock-word value.
4952 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
4953 continue;
4954 }
4955 List->OnList = 0;
4956 OrderAccess::fence();
4957 List->unpark();
4958 return;
4959 }
4960 }
4961
4962
4963 void Threads::verify() {
4964 ALL_JAVA_THREADS(p) {
4965 p->verify();
4966 }
4967 VMThread* thread = VMThread::vm_thread();
4968 if (thread != NULL) thread->verify();
4969 }