1 /*
2 * Copyright (c) 1997, 2017, 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/gcId.hpp"
37 #include "gc/shared/gcLocker.inline.hpp"
38 #include "gc/shared/workgroup.hpp"
39 #include "interpreter/interpreter.hpp"
40 #include "interpreter/linkResolver.hpp"
41 #include "interpreter/oopMapCache.hpp"
42 #include "jvmtifiles/jvmtiEnv.hpp"
43 #include "logging/log.hpp"
44 #include "logging/logConfiguration.hpp"
45 #include "logging/logStream.hpp"
46 #include "memory/metaspaceShared.hpp"
47 #include "memory/oopFactory.hpp"
48 #include "memory/resourceArea.hpp"
49 #include "memory/universe.inline.hpp"
50 #include "oops/instanceKlass.hpp"
51 #include "oops/objArrayOop.hpp"
52 #include "oops/oop.inline.hpp"
53 #include "oops/symbol.hpp"
54 #include "oops/verifyOopClosure.hpp"
55 #include "prims/jvm_misc.hpp"
56 #include "prims/jvmtiExport.hpp"
57 #include "prims/jvmtiThreadState.hpp"
58 #include "prims/privilegedStack.hpp"
59 #include "runtime/arguments.hpp"
60 #include "runtime/atomic.hpp"
61 #include "runtime/biasedLocking.hpp"
62 #include "runtime/commandLineFlagConstraintList.hpp"
63 #include "runtime/commandLineFlagWriteableList.hpp"
64 #include "runtime/commandLineFlagRangeList.hpp"
65 #include "runtime/deoptimization.hpp"
66 #include "runtime/frame.inline.hpp"
67 #include "runtime/globals.hpp"
68 #include "runtime/handshake.hpp"
69 #include "runtime/init.hpp"
70 #include "runtime/interfaceSupport.hpp"
71 #include "runtime/java.hpp"
72 #include "runtime/javaCalls.hpp"
73 #include "runtime/jniPeriodicChecker.hpp"
74 #include "runtime/memprofiler.hpp"
75 #include "runtime/mutexLocker.hpp"
76 #include "runtime/objectMonitor.hpp"
77 #include "runtime/orderAccess.inline.hpp"
78 #include "runtime/osThread.hpp"
79 #include "runtime/prefetch.inline.hpp"
80 #include "runtime/safepoint.hpp"
81 #include "runtime/safepointMechanism.inline.hpp"
82 #include "runtime/sharedRuntime.hpp"
83 #include "runtime/statSampler.hpp"
84 #include "runtime/stubRoutines.hpp"
85 #include "runtime/sweeper.hpp"
86 #include "runtime/task.hpp"
87 #include "runtime/thread.inline.hpp"
88 #include "runtime/threadCritical.hpp"
89 #include "runtime/threadSMR.inline.hpp"
90 #include "runtime/timer.hpp"
91 #include "runtime/timerTrace.hpp"
92 #include "runtime/vframe.hpp"
93 #include "runtime/vframeArray.hpp"
94 #include "runtime/vframe_hp.hpp"
95 #include "runtime/vmThread.hpp"
96 #include "runtime/vm_operations.hpp"
97 #include "runtime/vm_version.hpp"
98 #include "services/attachListener.hpp"
99 #include "services/management.hpp"
100 #include "services/memTracker.hpp"
101 #include "services/threadService.hpp"
102 #include "trace/traceMacros.hpp"
103 #include "trace/tracing.hpp"
104 #include "utilities/align.hpp"
105 #include "utilities/defaultStream.hpp"
106 #include "utilities/dtrace.hpp"
107 #include "utilities/events.hpp"
108 #include "utilities/macros.hpp"
109 #include "utilities/preserveException.hpp"
110 #include "utilities/vmError.hpp"
111 #if INCLUDE_ALL_GCS
112 #include "gc/cms/concurrentMarkSweepThread.hpp"
113 #include "gc/g1/concurrentMarkThread.inline.hpp"
114 #include "gc/parallel/pcTasks.hpp"
115 #endif // INCLUDE_ALL_GCS
116 #if INCLUDE_JVMCI
117 #include "jvmci/jvmciCompiler.hpp"
118 #include "jvmci/jvmciRuntime.hpp"
119 #include "logging/logHandle.hpp"
120 #endif
121 #ifdef COMPILER1
122 #include "c1/c1_Compiler.hpp"
123 #endif
124 #ifdef COMPILER2
125 #include "opto/c2compiler.hpp"
126 #include "opto/idealGraphPrinter.hpp"
127 #endif
128 #if INCLUDE_RTM_OPT
129 #include "runtime/rtmLocking.hpp"
130 #endif
131
132 // Initialization after module runtime initialization
133 void universe_post_module_init(); // must happen after call_initPhase2
134
135 #ifdef DTRACE_ENABLED
136
137 // Only bother with this argument setup if dtrace is available
138
139 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
140 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
141
142 #define DTRACE_THREAD_PROBE(probe, javathread) \
143 { \
144 ResourceMark rm(this); \
145 int len = 0; \
146 const char* name = (javathread)->get_thread_name(); \
147 len = strlen(name); \
148 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
149 (char *) name, len, \
150 java_lang_Thread::thread_id((javathread)->threadObj()), \
151 (uintptr_t) (javathread)->osthread()->thread_id(), \
152 java_lang_Thread::is_daemon((javathread)->threadObj())); \
153 }
154
155 #else // ndef DTRACE_ENABLED
156
157 #define DTRACE_THREAD_PROBE(probe, javathread)
158
159 #endif // ndef DTRACE_ENABLED
160
161 #ifndef USE_LIBRARY_BASED_TLS_ONLY
162 // Current thread is maintained as a thread-local variable
163 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
164 #endif
165 // Class hierarchy
166 // - Thread
167 // - VMThread
168 // - WatcherThread
169 // - ConcurrentMarkSweepThread
170 // - JavaThread
171 // - CompilerThread
172
173 // ======= Thread ========
174 // Support for forcing alignment of thread objects for biased locking
175 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
176 if (UseBiasedLocking) {
177 const int alignment = markOopDesc::biased_lock_alignment;
178 size_t aligned_size = size + (alignment - sizeof(intptr_t));
179 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
180 : AllocateHeap(aligned_size, flags, CURRENT_PC,
181 AllocFailStrategy::RETURN_NULL);
182 void* aligned_addr = align_up(real_malloc_addr, alignment);
183 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
184 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
185 "JavaThread alignment code overflowed allocated storage");
186 if (aligned_addr != real_malloc_addr) {
187 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
188 p2i(real_malloc_addr),
189 p2i(aligned_addr));
190 }
191 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
192 return aligned_addr;
193 } else {
194 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
195 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
196 }
197 }
198
199 void Thread::operator delete(void* p) {
200 if (UseBiasedLocking) {
201 FreeHeap(((Thread*) p)->_real_malloc_address);
202 } else {
203 FreeHeap(p);
204 }
205 }
206
207 void JavaThread::smr_delete() {
208 if (_on_thread_list) {
209 ThreadsSMRSupport::smr_delete(this);
210 } else {
211 delete this;
212 }
213 }
214
215 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
216 // JavaThread
217
218
219 Thread::Thread() {
220 // stack and get_thread
221 set_stack_base(NULL);
222 set_stack_size(0);
223 set_self_raw_id(0);
224 set_lgrp_id(-1);
225 DEBUG_ONLY(clear_suspendible_thread();)
226
227 // allocated data structures
228 set_osthread(NULL);
229 set_resource_area(new (mtThread)ResourceArea());
230 DEBUG_ONLY(_current_resource_mark = NULL;)
231 set_handle_area(new (mtThread) HandleArea(NULL));
232 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
233 set_active_handles(NULL);
234 set_free_handle_block(NULL);
235 set_last_handle_mark(NULL);
236
237 // This initial value ==> never claimed.
238 _oops_do_parity = 0;
239 _threads_hazard_ptr = NULL;
240 _nested_threads_hazard_ptr = NULL;
241 _nested_threads_hazard_ptr_cnt = 0;
242
243 // the handle mark links itself to last_handle_mark
244 new HandleMark(this);
245
246 // plain initialization
247 debug_only(_owned_locks = NULL;)
248 debug_only(_allow_allocation_count = 0;)
249 NOT_PRODUCT(_allow_safepoint_count = 0;)
250 NOT_PRODUCT(_skip_gcalot = false;)
251 _jvmti_env_iteration_count = 0;
252 set_allocated_bytes(0);
253 _vm_operation_started_count = 0;
254 _vm_operation_completed_count = 0;
255 _current_pending_monitor = NULL;
256 _current_pending_monitor_is_from_java = true;
257 _current_waiting_monitor = NULL;
258 _num_nested_signal = 0;
259 omFreeList = NULL;
260 omFreeCount = 0;
261 omFreeProvision = 32;
262 omInUseList = NULL;
263 omInUseCount = 0;
264
265 #ifdef ASSERT
266 _visited_for_critical_count = false;
267 #endif
268
269 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
270 Monitor::_safepoint_check_sometimes);
271 _suspend_flags = 0;
272
273 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
274 _hashStateX = os::random();
275 _hashStateY = 842502087;
276 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
277 _hashStateW = 273326509;
278
279 _OnTrap = 0;
280 _schedctl = NULL;
281 _Stalled = 0;
282 _TypeTag = 0x2BAD;
283
284 // Many of the following fields are effectively final - immutable
285 // Note that nascent threads can't use the Native Monitor-Mutex
286 // construct until the _MutexEvent is initialized ...
287 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
288 // we might instead use a stack of ParkEvents that we could provision on-demand.
289 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
290 // and ::Release()
291 _ParkEvent = ParkEvent::Allocate(this);
292 _SleepEvent = ParkEvent::Allocate(this);
293 _MutexEvent = ParkEvent::Allocate(this);
294 _MuxEvent = ParkEvent::Allocate(this);
295
296 #ifdef CHECK_UNHANDLED_OOPS
297 if (CheckUnhandledOops) {
298 _unhandled_oops = new UnhandledOops(this);
299 }
300 #endif // CHECK_UNHANDLED_OOPS
301 #ifdef ASSERT
302 if (UseBiasedLocking) {
303 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
304 assert(this == _real_malloc_address ||
305 this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment),
306 "bug in forced alignment of thread objects");
307 }
308 #endif // ASSERT
309
310 _oom_during_evac = 0;
311 #ifdef INCLUDE_ALL_GCS
312 _gclab = NULL;
313 #endif
314 }
315
316 void Thread::set_oom_during_evac(bool oom) {
317 if (oom) {
318 _oom_during_evac |= 1;
319 } else {
320 _oom_during_evac &= ~1;
321 }
322 }
323
324 bool Thread::is_oom_during_evac() const {
325 return (_oom_during_evac & 1) == 1;
326 }
327
328 #ifdef ASSERT
329 void Thread::set_evac_allowed(bool evac_allowed) {
330 if (evac_allowed) {
331 _oom_during_evac |= 2;
332 } else {
333 _oom_during_evac &= ~2;
334 }
335 }
336
337 bool Thread::is_evac_allowed() const {
338 return (_oom_during_evac & 2) == 2;
339 }
340 #endif
341
342 void Thread::initialize_thread_current() {
343 #ifndef USE_LIBRARY_BASED_TLS_ONLY
344 assert(_thr_current == NULL, "Thread::current already initialized");
345 _thr_current = this;
346 #endif
347 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
348 ThreadLocalStorage::set_thread(this);
349 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
350 }
351
352 void Thread::clear_thread_current() {
353 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
354 #ifndef USE_LIBRARY_BASED_TLS_ONLY
355 _thr_current = NULL;
356 #endif
357 ThreadLocalStorage::set_thread(NULL);
358 }
359
360 void Thread::record_stack_base_and_size() {
361 set_stack_base(os::current_stack_base());
362 set_stack_size(os::current_stack_size());
363 // CR 7190089: on Solaris, primordial thread's stack is adjusted
364 // in initialize_thread(). Without the adjustment, stack size is
365 // incorrect if stack is set to unlimited (ulimit -s unlimited).
366 // So far, only Solaris has real implementation of initialize_thread().
367 //
368 // set up any platform-specific state.
369 os::initialize_thread(this);
370
371 // Set stack limits after thread is initialized.
372 if (is_Java_thread()) {
373 ((JavaThread*) this)->set_stack_overflow_limit();
374 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
375 }
376 #if INCLUDE_NMT
377 // record thread's native stack, stack grows downward
378 MemTracker::record_thread_stack(stack_end(), stack_size());
379 #endif // INCLUDE_NMT
380 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
381 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
382 os::current_thread_id(), p2i(stack_base() - stack_size()),
383 p2i(stack_base()), stack_size()/1024);
384 }
385
386
387 Thread::~Thread() {
388 EVENT_THREAD_DESTRUCT(this);
389
390 // stack_base can be NULL if the thread is never started or exited before
391 // record_stack_base_and_size called. Although, we would like to ensure
392 // that all started threads do call record_stack_base_and_size(), there is
393 // not proper way to enforce that.
394 #if INCLUDE_NMT
395 if (_stack_base != NULL) {
396 MemTracker::release_thread_stack(stack_end(), stack_size());
397 #ifdef ASSERT
398 set_stack_base(NULL);
399 #endif
400 }
401 #endif // INCLUDE_NMT
402
403 // deallocate data structures
404 delete resource_area();
405 // since the handle marks are using the handle area, we have to deallocated the root
406 // handle mark before deallocating the thread's handle area,
407 assert(last_handle_mark() != NULL, "check we have an element");
408 delete last_handle_mark();
409 assert(last_handle_mark() == NULL, "check we have reached the end");
410
411 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
412 // We NULL out the fields for good hygiene.
413 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
414 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
415 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
416 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
417
418 delete handle_area();
419 delete metadata_handles();
420
421 // SR_handler uses this as a termination indicator -
422 // needs to happen before os::free_thread()
423 delete _SR_lock;
424 _SR_lock = NULL;
425
426 // osthread() can be NULL, if creation of thread failed.
427 if (osthread() != NULL) os::free_thread(osthread());
428
429 // clear Thread::current if thread is deleting itself.
430 // Needed to ensure JNI correctly detects non-attached threads.
431 if (this == Thread::current()) {
432 clear_thread_current();
433 }
434
435 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
436 }
437
438 // NOTE: dummy function for assertion purpose.
439 void Thread::run() {
440 ShouldNotReachHere();
441 }
442
443 #ifdef ASSERT
444 // A JavaThread is considered "dangling" if it is not the current
445 // thread, has been added the Threads list, the system is not at a
446 // safepoint and the Thread is not "protected".
447 //
448 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
449 assert(!thread->is_Java_thread() || Thread::current() == thread ||
450 !((JavaThread *) thread)->on_thread_list() ||
451 SafepointSynchronize::is_at_safepoint() ||
452 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
453 "possibility of dangling Thread pointer");
454 }
455 #endif
456
457 ThreadPriority Thread::get_priority(const Thread* const thread) {
458 ThreadPriority priority;
459 // Can return an error!
460 (void)os::get_priority(thread, priority);
461 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
462 return priority;
463 }
464
465 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
466 debug_only(check_for_dangling_thread_pointer(thread);)
467 // Can return an error!
468 (void)os::set_priority(thread, priority);
469 }
470
471
472 void Thread::start(Thread* thread) {
473 // Start is different from resume in that its safety is guaranteed by context or
474 // being called from a Java method synchronized on the Thread object.
475 if (!DisableStartThread) {
476 if (thread->is_Java_thread()) {
477 // Initialize the thread state to RUNNABLE before starting this thread.
478 // Can not set it after the thread started because we do not know the
479 // exact thread state at that time. It could be in MONITOR_WAIT or
480 // in SLEEPING or some other state.
481 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
482 java_lang_Thread::RUNNABLE);
483 }
484 os::start_thread(thread);
485 }
486 }
487
488 // Enqueue a VM_Operation to do the job for us - sometime later
489 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
490 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
491 VMThread::execute(vm_stop);
492 }
493
494
495 // Check if an external suspend request has completed (or has been
496 // cancelled). Returns true if the thread is externally suspended and
497 // false otherwise.
498 //
499 // The bits parameter returns information about the code path through
500 // the routine. Useful for debugging:
501 //
502 // set in is_ext_suspend_completed():
503 // 0x00000001 - routine was entered
504 // 0x00000010 - routine return false at end
505 // 0x00000100 - thread exited (return false)
506 // 0x00000200 - suspend request cancelled (return false)
507 // 0x00000400 - thread suspended (return true)
508 // 0x00001000 - thread is in a suspend equivalent state (return true)
509 // 0x00002000 - thread is native and walkable (return true)
510 // 0x00004000 - thread is native_trans and walkable (needed retry)
511 //
512 // set in wait_for_ext_suspend_completion():
513 // 0x00010000 - routine was entered
514 // 0x00020000 - suspend request cancelled before loop (return false)
515 // 0x00040000 - thread suspended before loop (return true)
516 // 0x00080000 - suspend request cancelled in loop (return false)
517 // 0x00100000 - thread suspended in loop (return true)
518 // 0x00200000 - suspend not completed during retry loop (return false)
519
520 // Helper class for tracing suspend wait debug bits.
521 //
522 // 0x00000100 indicates that the target thread exited before it could
523 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
524 // 0x00080000 each indicate a cancelled suspend request so they don't
525 // count as wait failures either.
526 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
527
528 class TraceSuspendDebugBits : public StackObj {
529 private:
530 JavaThread * jt;
531 bool is_wait;
532 bool called_by_wait; // meaningful when !is_wait
533 uint32_t * bits;
534
535 public:
536 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
537 uint32_t *_bits) {
538 jt = _jt;
539 is_wait = _is_wait;
540 called_by_wait = _called_by_wait;
541 bits = _bits;
542 }
543
544 ~TraceSuspendDebugBits() {
545 if (!is_wait) {
546 #if 1
547 // By default, don't trace bits for is_ext_suspend_completed() calls.
548 // That trace is very chatty.
549 return;
550 #else
551 if (!called_by_wait) {
552 // If tracing for is_ext_suspend_completed() is enabled, then only
553 // trace calls to it from wait_for_ext_suspend_completion()
554 return;
555 }
556 #endif
557 }
558
559 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
560 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
561 MutexLocker ml(Threads_lock); // needed for get_thread_name()
562 ResourceMark rm;
563
564 tty->print_cr(
565 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
566 jt->get_thread_name(), *bits);
567
568 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
569 }
570 }
571 }
572 };
573 #undef DEBUG_FALSE_BITS
574
575
576 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
577 uint32_t *bits) {
578 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
579
580 bool did_trans_retry = false; // only do thread_in_native_trans retry once
581 bool do_trans_retry; // flag to force the retry
582
583 *bits |= 0x00000001;
584
585 do {
586 do_trans_retry = false;
587
588 if (is_exiting()) {
589 // Thread is in the process of exiting. This is always checked
590 // first to reduce the risk of dereferencing a freed JavaThread.
591 *bits |= 0x00000100;
592 return false;
593 }
594
595 if (!is_external_suspend()) {
596 // Suspend request is cancelled. This is always checked before
597 // is_ext_suspended() to reduce the risk of a rogue resume
598 // confusing the thread that made the suspend request.
599 *bits |= 0x00000200;
600 return false;
601 }
602
603 if (is_ext_suspended()) {
604 // thread is suspended
605 *bits |= 0x00000400;
606 return true;
607 }
608
609 // Now that we no longer do hard suspends of threads running
610 // native code, the target thread can be changing thread state
611 // while we are in this routine:
612 //
613 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
614 //
615 // We save a copy of the thread state as observed at this moment
616 // and make our decision about suspend completeness based on the
617 // copy. This closes the race where the thread state is seen as
618 // _thread_in_native_trans in the if-thread_blocked check, but is
619 // seen as _thread_blocked in if-thread_in_native_trans check.
620 JavaThreadState save_state = thread_state();
621
622 if (save_state == _thread_blocked && is_suspend_equivalent()) {
623 // If the thread's state is _thread_blocked and this blocking
624 // condition is known to be equivalent to a suspend, then we can
625 // consider the thread to be externally suspended. This means that
626 // the code that sets _thread_blocked has been modified to do
627 // self-suspension if the blocking condition releases. We also
628 // used to check for CONDVAR_WAIT here, but that is now covered by
629 // the _thread_blocked with self-suspension check.
630 //
631 // Return true since we wouldn't be here unless there was still an
632 // external suspend request.
633 *bits |= 0x00001000;
634 return true;
635 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
636 // Threads running native code will self-suspend on native==>VM/Java
637 // transitions. If its stack is walkable (should always be the case
638 // unless this function is called before the actual java_suspend()
639 // call), then the wait is done.
640 *bits |= 0x00002000;
641 return true;
642 } else if (!called_by_wait && !did_trans_retry &&
643 save_state == _thread_in_native_trans &&
644 frame_anchor()->walkable()) {
645 // The thread is transitioning from thread_in_native to another
646 // thread state. check_safepoint_and_suspend_for_native_trans()
647 // will force the thread to self-suspend. If it hasn't gotten
648 // there yet we may have caught the thread in-between the native
649 // code check above and the self-suspend. Lucky us. If we were
650 // called by wait_for_ext_suspend_completion(), then it
651 // will be doing the retries so we don't have to.
652 //
653 // Since we use the saved thread state in the if-statement above,
654 // there is a chance that the thread has already transitioned to
655 // _thread_blocked by the time we get here. In that case, we will
656 // make a single unnecessary pass through the logic below. This
657 // doesn't hurt anything since we still do the trans retry.
658
659 *bits |= 0x00004000;
660
661 // Once the thread leaves thread_in_native_trans for another
662 // thread state, we break out of this retry loop. We shouldn't
663 // need this flag to prevent us from getting back here, but
664 // sometimes paranoia is good.
665 did_trans_retry = true;
666
667 // We wait for the thread to transition to a more usable state.
668 for (int i = 1; i <= SuspendRetryCount; i++) {
669 // We used to do an "os::yield_all(i)" call here with the intention
670 // that yielding would increase on each retry. However, the parameter
671 // is ignored on Linux which means the yield didn't scale up. Waiting
672 // on the SR_lock below provides a much more predictable scale up for
673 // the delay. It also provides a simple/direct point to check for any
674 // safepoint requests from the VMThread
675
676 // temporarily drops SR_lock while doing wait with safepoint check
677 // (if we're a JavaThread - the WatcherThread can also call this)
678 // and increase delay with each retry
679 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
680
681 // check the actual thread state instead of what we saved above
682 if (thread_state() != _thread_in_native_trans) {
683 // the thread has transitioned to another thread state so
684 // try all the checks (except this one) one more time.
685 do_trans_retry = true;
686 break;
687 }
688 } // end retry loop
689
690
691 }
692 } while (do_trans_retry);
693
694 *bits |= 0x00000010;
695 return false;
696 }
697
698 // Wait for an external suspend request to complete (or be cancelled).
699 // Returns true if the thread is externally suspended and false otherwise.
700 //
701 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
702 uint32_t *bits) {
703 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
704 false /* !called_by_wait */, bits);
705
706 // local flag copies to minimize SR_lock hold time
707 bool is_suspended;
708 bool pending;
709 uint32_t reset_bits;
710
711 // set a marker so is_ext_suspend_completed() knows we are the caller
712 *bits |= 0x00010000;
713
714 // We use reset_bits to reinitialize the bits value at the top of
715 // each retry loop. This allows the caller to make use of any
716 // unused bits for their own marking purposes.
717 reset_bits = *bits;
718
719 {
720 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
721 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
722 delay, bits);
723 pending = is_external_suspend();
724 }
725 // must release SR_lock to allow suspension to complete
726
727 if (!pending) {
728 // A cancelled suspend request is the only false return from
729 // is_ext_suspend_completed() that keeps us from entering the
730 // retry loop.
731 *bits |= 0x00020000;
732 return false;
733 }
734
735 if (is_suspended) {
736 *bits |= 0x00040000;
737 return true;
738 }
739
740 for (int i = 1; i <= retries; i++) {
741 *bits = reset_bits; // reinit to only track last retry
742
743 // We used to do an "os::yield_all(i)" call here with the intention
744 // that yielding would increase on each retry. However, the parameter
745 // is ignored on Linux which means the yield didn't scale up. Waiting
746 // on the SR_lock below provides a much more predictable scale up for
747 // the delay. It also provides a simple/direct point to check for any
748 // safepoint requests from the VMThread
749
750 {
751 MutexLocker ml(SR_lock());
752 // wait with safepoint check (if we're a JavaThread - the WatcherThread
753 // can also call this) and increase delay with each retry
754 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
755
756 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
757 delay, bits);
758
759 // It is possible for the external suspend request to be cancelled
760 // (by a resume) before the actual suspend operation is completed.
761 // Refresh our local copy to see if we still need to wait.
762 pending = is_external_suspend();
763 }
764
765 if (!pending) {
766 // A cancelled suspend request is the only false return from
767 // is_ext_suspend_completed() that keeps us from staying in the
768 // retry loop.
769 *bits |= 0x00080000;
770 return false;
771 }
772
773 if (is_suspended) {
774 *bits |= 0x00100000;
775 return true;
776 }
777 } // end retry loop
778
779 // thread did not suspend after all our retries
780 *bits |= 0x00200000;
781 return false;
782 }
783
784 // Called from API entry points which perform stack walking. If the
785 // associated JavaThread is the current thread, then wait_for_suspend
786 // is not used. Otherwise, it determines if we should wait for the
787 // "other" thread to complete external suspension. (NOTE: in future
788 // releases the suspension mechanism should be reimplemented so this
789 // is not necessary.)
790 //
791 bool
792 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
793 if (this != JavaThread::current()) {
794 // "other" threads require special handling.
795 if (wait_for_suspend) {
796 // We are allowed to wait for the external suspend to complete
797 // so give the other thread a chance to get suspended.
798 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
799 SuspendRetryDelay, bits)) {
800 // Didn't make it so let the caller know.
801 return false;
802 }
803 }
804 // We aren't allowed to wait for the external suspend to complete
805 // so if the other thread isn't externally suspended we need to
806 // let the caller know.
807 else if (!is_ext_suspend_completed_with_lock(bits)) {
808 return false;
809 }
810 }
811
812 return true;
813 }
814
815 #ifndef PRODUCT
816 void JavaThread::record_jump(address target, address instr, const char* file,
817 int line) {
818
819 // This should not need to be atomic as the only way for simultaneous
820 // updates is via interrupts. Even then this should be rare or non-existent
821 // and we don't care that much anyway.
822
823 int index = _jmp_ring_index;
824 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
825 _jmp_ring[index]._target = (intptr_t) target;
826 _jmp_ring[index]._instruction = (intptr_t) instr;
827 _jmp_ring[index]._file = file;
828 _jmp_ring[index]._line = line;
829 }
830 #endif // PRODUCT
831
832 void Thread::interrupt(Thread* thread) {
833 debug_only(check_for_dangling_thread_pointer(thread);)
834 os::interrupt(thread);
835 }
836
837 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
838 debug_only(check_for_dangling_thread_pointer(thread);)
839 // Note: If clear_interrupted==false, this simply fetches and
840 // returns the value of the field osthread()->interrupted().
841 return os::is_interrupted(thread, clear_interrupted);
842 }
843
844
845 // GC Support
846 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
847 int thread_parity = _oops_do_parity;
848 if (thread_parity != strong_roots_parity) {
849 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
850 if (res == thread_parity) {
851 return true;
852 } else {
853 guarantee(res == strong_roots_parity, "Or else what?");
854 return false;
855 }
856 }
857 return false;
858 }
859
860 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
861 active_handles()->oops_do(f);
862 // Do oop for ThreadShadow
863 f->do_oop((oop*)&_pending_exception);
864 handle_area()->oops_do(f);
865
866 if (MonitorInUseLists) {
867 // When using thread local monitor lists, we scan them here,
868 // and the remaining global monitors in ObjectSynchronizer::oops_do().
869 VM_Operation* op = VMThread::vm_operation();
870 if (op != NULL && op->deflates_idle_monitors()) {
871 DeflateMonitorCounters counters; // Dummy for now.
872 ObjectSynchronizer::deflate_thread_local_monitors(this, &counters, f);
873 } else {
874 ObjectSynchronizer::thread_local_used_oops_do(this, f);
875 }
876 }
877 }
878
879 void Thread::metadata_handles_do(void f(Metadata*)) {
880 // Only walk the Handles in Thread.
881 if (metadata_handles() != NULL) {
882 for (int i = 0; i< metadata_handles()->length(); i++) {
883 f(metadata_handles()->at(i));
884 }
885 }
886 }
887
888 void Thread::print_on(outputStream* st) const {
889 // get_priority assumes osthread initialized
890 if (osthread() != NULL) {
891 int os_prio;
892 if (os::get_native_priority(this, &os_prio) == OS_OK) {
893 st->print("os_prio=%d ", os_prio);
894 }
895 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
896 ext().print_on(st);
897 osthread()->print_on(st);
898 }
899 if (_threads_hazard_ptr != NULL) {
900 st->print("_threads_hazard_ptr=" INTPTR_FORMAT, p2i(_threads_hazard_ptr));
901 }
902 if (_nested_threads_hazard_ptr != NULL) {
903 print_nested_threads_hazard_ptrs_on(st);
904 }
905 st->print(" ");
906 debug_only(if (WizardMode) print_owned_locks_on(st);)
907 }
908
909 void Thread::print_nested_threads_hazard_ptrs_on(outputStream* st) const {
910 assert(_nested_threads_hazard_ptr != NULL, "must be set to print");
911
912 if (EnableThreadSMRStatistics) {
913 st->print(", _nested_threads_hazard_ptr_cnt=%u", _nested_threads_hazard_ptr_cnt);
914 }
915 st->print(", _nested_threads_hazard_ptrs=");
916 for (NestedThreadsList* node = _nested_threads_hazard_ptr; node != NULL;
917 node = node->next()) {
918 if (node != _nested_threads_hazard_ptr) {
919 // First node does not need a comma-space separator.
920 st->print(", ");
921 }
922 st->print(INTPTR_FORMAT, p2i(node->t_list()));
923 }
924 }
925
926 // Thread::print_on_error() is called by fatal error handler. Don't use
927 // any lock or allocate memory.
928 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
929 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
930
931 if (is_VM_thread()) { st->print("VMThread"); }
932 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
933 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
934 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
935 else { st->print("Thread"); }
936
937 if (is_Named_thread()) {
938 st->print(" \"%s\"", name());
939 }
940
941 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
942 p2i(stack_end()), p2i(stack_base()));
943
944 if (osthread()) {
945 st->print(" [id=%d]", osthread()->thread_id());
946 }
947
948 if (_threads_hazard_ptr != NULL) {
949 st->print(" _threads_hazard_ptr=" INTPTR_FORMAT, p2i(_threads_hazard_ptr));
950 }
951 if (_nested_threads_hazard_ptr != NULL) {
952 print_nested_threads_hazard_ptrs_on(st);
953 }
954 }
955
956 void Thread::print_value_on(outputStream* st) const {
957 if (is_Named_thread()) {
958 st->print(" \"%s\" ", name());
959 }
960 st->print(INTPTR_FORMAT, p2i(this)); // print address
961 }
962
963 #ifdef ASSERT
964 void Thread::print_owned_locks_on(outputStream* st) const {
965 Monitor *cur = _owned_locks;
966 if (cur == NULL) {
967 st->print(" (no locks) ");
968 } else {
969 st->print_cr(" Locks owned:");
970 while (cur) {
971 cur->print_on(st);
972 cur = cur->next();
973 }
974 }
975 }
976
977 static int ref_use_count = 0;
978
979 bool Thread::owns_locks_but_compiled_lock() const {
980 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
981 if (cur != Compile_lock) return true;
982 }
983 return false;
984 }
985
986
987 #endif
988
989 #ifndef PRODUCT
990
991 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially
992 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that
993 // no threads which allow_vm_block's are held
994 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
995 // Check if current thread is allowed to block at a safepoint
996 if (!(_allow_safepoint_count == 0)) {
997 fatal("Possible safepoint reached by thread that does not allow it");
998 }
999 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
1000 fatal("LEAF method calling lock?");
1001 }
1002
1003 #ifdef ASSERT
1004 if (potential_vm_operation && is_Java_thread()
1005 && !Universe::is_bootstrapping()) {
1006 // Make sure we do not hold any locks that the VM thread also uses.
1007 // This could potentially lead to deadlocks
1008 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
1009 // Threads_lock is special, since the safepoint synchronization will not start before this is
1010 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
1011 // since it is used to transfer control between JavaThreads and the VMThread
1012 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
1013 if ((cur->allow_vm_block() &&
1014 cur != Threads_lock &&
1015 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
1016 cur != VMOperationRequest_lock &&
1017 cur != VMOperationQueue_lock) ||
1018 cur->rank() == Mutex::special) {
1019 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
1020 }
1021 }
1022 }
1023
1024 if (GCALotAtAllSafepoints) {
1025 // We could enter a safepoint here and thus have a gc
1026 InterfaceSupport::check_gc_alot();
1027 }
1028 #endif
1029 }
1030 #endif
1031
1032 bool Thread::is_in_stack(address adr) const {
1033 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
1034 address end = os::current_stack_pointer();
1035 // Allow non Java threads to call this without stack_base
1036 if (_stack_base == NULL) return true;
1037 if (stack_base() >= adr && adr >= end) return true;
1038
1039 return false;
1040 }
1041
1042 bool Thread::is_in_usable_stack(address adr) const {
1043 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1044 size_t usable_stack_size = _stack_size - stack_guard_size;
1045
1046 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1047 }
1048
1049
1050 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1051 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1052 // used for compilation in the future. If that change is made, the need for these methods
1053 // should be revisited, and they should be removed if possible.
1054
1055 bool Thread::is_lock_owned(address adr) const {
1056 return on_local_stack(adr);
1057 }
1058
1059 bool Thread::set_as_starting_thread() {
1060 // NOTE: this must be called inside the main thread.
1061 return os::create_main_thread((JavaThread*)this);
1062 }
1063
1064 static void initialize_class(Symbol* class_name, TRAPS) {
1065 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1066 InstanceKlass::cast(klass)->initialize(CHECK);
1067 }
1068
1069
1070 // Creates the initial ThreadGroup
1071 static Handle create_initial_thread_group(TRAPS) {
1072 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1073 InstanceKlass* ik = InstanceKlass::cast(k);
1074
1075 Handle system_instance = ik->allocate_instance_handle(CHECK_NH);
1076 {
1077 JavaValue result(T_VOID);
1078 JavaCalls::call_special(&result,
1079 system_instance,
1080 ik,
1081 vmSymbols::object_initializer_name(),
1082 vmSymbols::void_method_signature(),
1083 CHECK_NH);
1084 }
1085 Universe::set_system_thread_group(system_instance());
1086
1087 Handle main_instance = ik->allocate_instance_handle(CHECK_NH);
1088 {
1089 JavaValue result(T_VOID);
1090 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1091 JavaCalls::call_special(&result,
1092 main_instance,
1093 ik,
1094 vmSymbols::object_initializer_name(),
1095 vmSymbols::threadgroup_string_void_signature(),
1096 system_instance,
1097 string,
1098 CHECK_NH);
1099 }
1100 return main_instance;
1101 }
1102
1103 // Creates the initial Thread
1104 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1105 TRAPS) {
1106 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1107 InstanceKlass* ik = InstanceKlass::cast(k);
1108 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1109
1110 java_lang_Thread::set_thread(thread_oop(), thread);
1111 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1112 thread->set_threadObj(thread_oop());
1113
1114 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1115
1116 JavaValue result(T_VOID);
1117 JavaCalls::call_special(&result, thread_oop,
1118 ik,
1119 vmSymbols::object_initializer_name(),
1120 vmSymbols::threadgroup_string_void_signature(),
1121 thread_group,
1122 string,
1123 CHECK_NULL);
1124 return thread_oop();
1125 }
1126
1127 char java_runtime_name[128] = "";
1128 char java_runtime_version[128] = "";
1129
1130 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1131 static const char* get_java_runtime_name(TRAPS) {
1132 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1133 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1134 fieldDescriptor fd;
1135 bool found = k != NULL &&
1136 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1137 vmSymbols::string_signature(), &fd);
1138 if (found) {
1139 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1140 if (name_oop == NULL) {
1141 return NULL;
1142 }
1143 const char* name = java_lang_String::as_utf8_string(name_oop,
1144 java_runtime_name,
1145 sizeof(java_runtime_name));
1146 return name;
1147 } else {
1148 return NULL;
1149 }
1150 }
1151
1152 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1153 static const char* get_java_runtime_version(TRAPS) {
1154 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1155 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1156 fieldDescriptor fd;
1157 bool found = k != NULL &&
1158 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1159 vmSymbols::string_signature(), &fd);
1160 if (found) {
1161 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1162 if (name_oop == NULL) {
1163 return NULL;
1164 }
1165 const char* name = java_lang_String::as_utf8_string(name_oop,
1166 java_runtime_version,
1167 sizeof(java_runtime_version));
1168 return name;
1169 } else {
1170 return NULL;
1171 }
1172 }
1173
1174 // General purpose hook into Java code, run once when the VM is initialized.
1175 // The Java library method itself may be changed independently from the VM.
1176 static void call_postVMInitHook(TRAPS) {
1177 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1178 if (klass != NULL) {
1179 JavaValue result(T_VOID);
1180 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1181 vmSymbols::void_method_signature(),
1182 CHECK);
1183 }
1184 }
1185
1186 static void reset_vm_info_property(TRAPS) {
1187 // the vm info string
1188 ResourceMark rm(THREAD);
1189 const char *vm_info = VM_Version::vm_info_string();
1190
1191 // java.lang.System class
1192 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1193
1194 // setProperty arguments
1195 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1196 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1197
1198 // return value
1199 JavaValue r(T_OBJECT);
1200
1201 // public static String setProperty(String key, String value);
1202 JavaCalls::call_static(&r,
1203 klass,
1204 vmSymbols::setProperty_name(),
1205 vmSymbols::string_string_string_signature(),
1206 key_str,
1207 value_str,
1208 CHECK);
1209 }
1210
1211
1212 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1213 bool daemon, TRAPS) {
1214 assert(thread_group.not_null(), "thread group should be specified");
1215 assert(threadObj() == NULL, "should only create Java thread object once");
1216
1217 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1218 InstanceKlass* ik = InstanceKlass::cast(k);
1219 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1220
1221 java_lang_Thread::set_thread(thread_oop(), this);
1222 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1223 set_threadObj(thread_oop());
1224
1225 JavaValue result(T_VOID);
1226 if (thread_name != NULL) {
1227 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1228 // Thread gets assigned specified name and null target
1229 JavaCalls::call_special(&result,
1230 thread_oop,
1231 ik,
1232 vmSymbols::object_initializer_name(),
1233 vmSymbols::threadgroup_string_void_signature(),
1234 thread_group, // Argument 1
1235 name, // Argument 2
1236 THREAD);
1237 } else {
1238 // Thread gets assigned name "Thread-nnn" and null target
1239 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1240 JavaCalls::call_special(&result,
1241 thread_oop,
1242 ik,
1243 vmSymbols::object_initializer_name(),
1244 vmSymbols::threadgroup_runnable_void_signature(),
1245 thread_group, // Argument 1
1246 Handle(), // Argument 2
1247 THREAD);
1248 }
1249
1250
1251 if (daemon) {
1252 java_lang_Thread::set_daemon(thread_oop());
1253 }
1254
1255 if (HAS_PENDING_EXCEPTION) {
1256 return;
1257 }
1258
1259 Klass* group = SystemDictionary::ThreadGroup_klass();
1260 Handle threadObj(THREAD, this->threadObj());
1261
1262 JavaCalls::call_special(&result,
1263 thread_group,
1264 group,
1265 vmSymbols::add_method_name(),
1266 vmSymbols::thread_void_signature(),
1267 threadObj, // Arg 1
1268 THREAD);
1269 }
1270
1271 // NamedThread -- non-JavaThread subclasses with multiple
1272 // uniquely named instances should derive from this.
1273 NamedThread::NamedThread() : Thread() {
1274 _name = NULL;
1275 _processed_thread = NULL;
1276 _gc_id = GCId::undefined();
1277 }
1278
1279 NamedThread::~NamedThread() {
1280 if (_name != NULL) {
1281 FREE_C_HEAP_ARRAY(char, _name);
1282 _name = NULL;
1283 }
1284 }
1285
1286 void NamedThread::set_name(const char* format, ...) {
1287 guarantee(_name == NULL, "Only get to set name once.");
1288 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1289 guarantee(_name != NULL, "alloc failure");
1290 va_list ap;
1291 va_start(ap, format);
1292 jio_vsnprintf(_name, max_name_len, format, ap);
1293 va_end(ap);
1294 }
1295
1296 void NamedThread::initialize_named_thread() {
1297 set_native_thread_name(name());
1298 }
1299
1300 void NamedThread::print_on(outputStream* st) const {
1301 st->print("\"%s\" ", name());
1302 Thread::print_on(st);
1303 st->cr();
1304 }
1305
1306
1307 // ======= WatcherThread ========
1308
1309 // The watcher thread exists to simulate timer interrupts. It should
1310 // be replaced by an abstraction over whatever native support for
1311 // timer interrupts exists on the platform.
1312
1313 WatcherThread* WatcherThread::_watcher_thread = NULL;
1314 bool WatcherThread::_startable = false;
1315 volatile bool WatcherThread::_should_terminate = false;
1316
1317 WatcherThread::WatcherThread() : Thread() {
1318 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1319 if (os::create_thread(this, os::watcher_thread)) {
1320 _watcher_thread = this;
1321
1322 // Set the watcher thread to the highest OS priority which should not be
1323 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1324 // is created. The only normal thread using this priority is the reference
1325 // handler thread, which runs for very short intervals only.
1326 // If the VMThread's priority is not lower than the WatcherThread profiling
1327 // will be inaccurate.
1328 os::set_priority(this, MaxPriority);
1329 if (!DisableStartThread) {
1330 os::start_thread(this);
1331 }
1332 }
1333 }
1334
1335 int WatcherThread::sleep() const {
1336 // The WatcherThread does not participate in the safepoint protocol
1337 // for the PeriodicTask_lock because it is not a JavaThread.
1338 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1339
1340 if (_should_terminate) {
1341 // check for termination before we do any housekeeping or wait
1342 return 0; // we did not sleep.
1343 }
1344
1345 // remaining will be zero if there are no tasks,
1346 // causing the WatcherThread to sleep until a task is
1347 // enrolled
1348 int remaining = PeriodicTask::time_to_wait();
1349 int time_slept = 0;
1350
1351 // we expect this to timeout - we only ever get unparked when
1352 // we should terminate or when a new task has been enrolled
1353 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1354
1355 jlong time_before_loop = os::javaTimeNanos();
1356
1357 while (true) {
1358 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1359 remaining);
1360 jlong now = os::javaTimeNanos();
1361
1362 if (remaining == 0) {
1363 // if we didn't have any tasks we could have waited for a long time
1364 // consider the time_slept zero and reset time_before_loop
1365 time_slept = 0;
1366 time_before_loop = now;
1367 } else {
1368 // need to recalculate since we might have new tasks in _tasks
1369 time_slept = (int) ((now - time_before_loop) / 1000000);
1370 }
1371
1372 // Change to task list or spurious wakeup of some kind
1373 if (timedout || _should_terminate) {
1374 break;
1375 }
1376
1377 remaining = PeriodicTask::time_to_wait();
1378 if (remaining == 0) {
1379 // Last task was just disenrolled so loop around and wait until
1380 // another task gets enrolled
1381 continue;
1382 }
1383
1384 remaining -= time_slept;
1385 if (remaining <= 0) {
1386 break;
1387 }
1388 }
1389
1390 return time_slept;
1391 }
1392
1393 void WatcherThread::run() {
1394 assert(this == watcher_thread(), "just checking");
1395
1396 this->record_stack_base_and_size();
1397 this->set_native_thread_name(this->name());
1398 this->set_active_handles(JNIHandleBlock::allocate_block());
1399 while (true) {
1400 assert(watcher_thread() == Thread::current(), "thread consistency check");
1401 assert(watcher_thread() == this, "thread consistency check");
1402
1403 // Calculate how long it'll be until the next PeriodicTask work
1404 // should be done, and sleep that amount of time.
1405 int time_waited = sleep();
1406
1407 if (VMError::is_error_reported()) {
1408 // A fatal error has happened, the error handler(VMError::report_and_die)
1409 // should abort JVM after creating an error log file. However in some
1410 // rare cases, the error handler itself might deadlock. Here periodically
1411 // check for error reporting timeouts, and if it happens, just proceed to
1412 // abort the VM.
1413
1414 // This code is in WatcherThread because WatcherThread wakes up
1415 // periodically so the fatal error handler doesn't need to do anything;
1416 // also because the WatcherThread is less likely to crash than other
1417 // threads.
1418
1419 for (;;) {
1420 // Note: we use naked sleep in this loop because we want to avoid using
1421 // any kind of VM infrastructure which may be broken at this point.
1422 if (VMError::check_timeout()) {
1423 // We hit error reporting timeout. Error reporting was interrupted and
1424 // will be wrapping things up now (closing files etc). Give it some more
1425 // time, then quit the VM.
1426 os::naked_short_sleep(200);
1427 // Print a message to stderr.
1428 fdStream err(defaultStream::output_fd());
1429 err.print_raw_cr("# [ timer expired, abort... ]");
1430 // skip atexit/vm_exit/vm_abort hooks
1431 os::die();
1432 }
1433
1434 // Wait a second, then recheck for timeout.
1435 os::naked_short_sleep(999);
1436 }
1437 }
1438
1439 if (_should_terminate) {
1440 // check for termination before posting the next tick
1441 break;
1442 }
1443
1444 PeriodicTask::real_time_tick(time_waited);
1445 }
1446
1447 // Signal that it is terminated
1448 {
1449 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1450 _watcher_thread = NULL;
1451 Terminator_lock->notify();
1452 }
1453 }
1454
1455 void WatcherThread::start() {
1456 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1457
1458 if (watcher_thread() == NULL && _startable) {
1459 _should_terminate = false;
1460 // Create the single instance of WatcherThread
1461 new WatcherThread();
1462 }
1463 }
1464
1465 void WatcherThread::make_startable() {
1466 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1467 _startable = true;
1468 }
1469
1470 void WatcherThread::stop() {
1471 {
1472 // Follow normal safepoint aware lock enter protocol since the
1473 // WatcherThread is stopped by another JavaThread.
1474 MutexLocker ml(PeriodicTask_lock);
1475 _should_terminate = true;
1476
1477 WatcherThread* watcher = watcher_thread();
1478 if (watcher != NULL) {
1479 // unpark the WatcherThread so it can see that it should terminate
1480 watcher->unpark();
1481 }
1482 }
1483
1484 MutexLocker mu(Terminator_lock);
1485
1486 while (watcher_thread() != NULL) {
1487 // This wait should make safepoint checks, wait without a timeout,
1488 // and wait as a suspend-equivalent condition.
1489 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1490 Mutex::_as_suspend_equivalent_flag);
1491 }
1492 }
1493
1494 void WatcherThread::unpark() {
1495 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1496 PeriodicTask_lock->notify();
1497 }
1498
1499 void WatcherThread::print_on(outputStream* st) const {
1500 st->print("\"%s\" ", name());
1501 Thread::print_on(st);
1502 st->cr();
1503 }
1504
1505 // ======= JavaThread ========
1506
1507 #if INCLUDE_JVMCI
1508
1509 jlong* JavaThread::_jvmci_old_thread_counters;
1510
1511 bool jvmci_counters_include(JavaThread* thread) {
1512 oop threadObj = thread->threadObj();
1513 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1514 }
1515
1516 void JavaThread::collect_counters(typeArrayOop array) {
1517 if (JVMCICounterSize > 0) {
1518 MutexLocker tl(Threads_lock);
1519 JavaThreadIteratorWithHandle jtiwh;
1520 for (int i = 0; i < array->length(); i++) {
1521 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1522 }
1523 for (; JavaThread *tp = jtiwh.next(); ) {
1524 if (jvmci_counters_include(tp)) {
1525 for (int i = 0; i < array->length(); i++) {
1526 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1527 }
1528 }
1529 }
1530 }
1531 }
1532
1533 #endif // INCLUDE_JVMCI
1534
1535 // A JavaThread is a normal Java thread
1536
1537 void JavaThread::initialize() {
1538 // Initialize fields
1539
1540 set_saved_exception_pc(NULL);
1541 set_threadObj(NULL);
1542 _anchor.clear();
1543 set_entry_point(NULL);
1544 set_jni_functions(jni_functions());
1545 set_callee_target(NULL);
1546 set_vm_result(NULL);
1547 set_vm_result_2(NULL);
1548 set_vframe_array_head(NULL);
1549 set_vframe_array_last(NULL);
1550 set_deferred_locals(NULL);
1551 set_deopt_mark(NULL);
1552 set_deopt_compiled_method(NULL);
1553 clear_must_deopt_id();
1554 set_monitor_chunks(NULL);
1555 set_next(NULL);
1556 _on_thread_list = false;
1557 set_thread_state(_thread_new);
1558 _terminated = _not_terminated;
1559 _privileged_stack_top = NULL;
1560 _array_for_gc = NULL;
1561 _suspend_equivalent = false;
1562 _in_deopt_handler = 0;
1563 _doing_unsafe_access = false;
1564 _stack_guard_state = stack_guard_unused;
1565 #if INCLUDE_JVMCI
1566 _pending_monitorenter = false;
1567 _pending_deoptimization = -1;
1568 _pending_failed_speculation = NULL;
1569 _pending_transfer_to_interpreter = false;
1570 _adjusting_comp_level = false;
1571 _jvmci._alternate_call_target = NULL;
1572 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1573 if (JVMCICounterSize > 0) {
1574 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1575 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1576 } else {
1577 _jvmci_counters = NULL;
1578 }
1579 #endif // INCLUDE_JVMCI
1580 _reserved_stack_activation = NULL; // stack base not known yet
1581 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1582 _exception_pc = 0;
1583 _exception_handler_pc = 0;
1584 _is_method_handle_return = 0;
1585 _jvmti_thread_state= NULL;
1586 _should_post_on_exceptions_flag = JNI_FALSE;
1587 _jvmti_get_loaded_classes_closure = NULL;
1588 _interp_only_mode = 0;
1589 _special_runtime_exit_condition = _no_async_condition;
1590 _pending_async_exception = NULL;
1591 _thread_stat = NULL;
1592 _thread_stat = new ThreadStatistics();
1593 _blocked_on_compilation = false;
1594 _jni_active_critical = 0;
1595 _pending_jni_exception_check_fn = NULL;
1596 _do_not_unlock_if_synchronized = false;
1597 _cached_monitor_info = NULL;
1598 _parker = Parker::Allocate(this);
1599
1600 #ifndef PRODUCT
1601 _jmp_ring_index = 0;
1602 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1603 record_jump(NULL, NULL, NULL, 0);
1604 }
1605 #endif // PRODUCT
1606
1607 // Setup safepoint state info for this thread
1608 ThreadSafepointState::create(this);
1609
1610 debug_only(_java_call_counter = 0);
1611
1612 // JVMTI PopFrame support
1613 _popframe_condition = popframe_inactive;
1614 _popframe_preserved_args = NULL;
1615 _popframe_preserved_args_size = 0;
1616 _frames_to_pop_failed_realloc = 0;
1617
1618 if (SafepointMechanism::uses_thread_local_poll()) {
1619 SafepointMechanism::initialize_header(this);
1620 }
1621
1622 pd_initialize();
1623 }
1624
1625 #if INCLUDE_ALL_GCS
1626 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1627 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1628 char JavaThread::_gc_state_global = 0;
1629 #endif // INCLUDE_ALL_GCS
1630
1631 JavaThread::JavaThread(bool is_attaching_via_jni) :
1632 Thread()
1633 #if INCLUDE_ALL_GCS
1634 , _satb_mark_queue(&_satb_mark_queue_set),
1635 _dirty_card_queue(&_dirty_card_queue_set),
1636 _gc_state(_gc_state_global)
1637 #endif // INCLUDE_ALL_GCS
1638 {
1639 initialize();
1640 if (is_attaching_via_jni) {
1641 _jni_attach_state = _attaching_via_jni;
1642 } else {
1643 _jni_attach_state = _not_attaching_via_jni;
1644 }
1645 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1646 }
1647
1648 bool JavaThread::reguard_stack(address cur_sp) {
1649 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1650 && _stack_guard_state != stack_guard_reserved_disabled) {
1651 return true; // Stack already guarded or guard pages not needed.
1652 }
1653
1654 if (register_stack_overflow()) {
1655 // For those architectures which have separate register and
1656 // memory stacks, we must check the register stack to see if
1657 // it has overflowed.
1658 return false;
1659 }
1660
1661 // Java code never executes within the yellow zone: the latter is only
1662 // there to provoke an exception during stack banging. If java code
1663 // is executing there, either StackShadowPages should be larger, or
1664 // some exception code in c1, c2 or the interpreter isn't unwinding
1665 // when it should.
1666 guarantee(cur_sp > stack_reserved_zone_base(),
1667 "not enough space to reguard - increase StackShadowPages");
1668 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1669 enable_stack_yellow_reserved_zone();
1670 if (reserved_stack_activation() != stack_base()) {
1671 set_reserved_stack_activation(stack_base());
1672 }
1673 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1674 set_reserved_stack_activation(stack_base());
1675 enable_stack_reserved_zone();
1676 }
1677 return true;
1678 }
1679
1680 bool JavaThread::reguard_stack(void) {
1681 return reguard_stack(os::current_stack_pointer());
1682 }
1683
1684
1685 void JavaThread::block_if_vm_exited() {
1686 if (_terminated == _vm_exited) {
1687 // _vm_exited is set at safepoint, and Threads_lock is never released
1688 // we will block here forever
1689 Threads_lock->lock_without_safepoint_check();
1690 ShouldNotReachHere();
1691 }
1692 }
1693
1694
1695 // Remove this ifdef when C1 is ported to the compiler interface.
1696 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1697 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1698
1699 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1700 Thread()
1701 #if INCLUDE_ALL_GCS
1702 , _satb_mark_queue(&_satb_mark_queue_set),
1703 _dirty_card_queue(&_dirty_card_queue_set),
1704 _gc_state(_gc_state_global)
1705 #endif // INCLUDE_ALL_GCS
1706 {
1707 initialize();
1708 _jni_attach_state = _not_attaching_via_jni;
1709 set_entry_point(entry_point);
1710 // Create the native thread itself.
1711 // %note runtime_23
1712 os::ThreadType thr_type = os::java_thread;
1713 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1714 os::java_thread;
1715 os::create_thread(this, thr_type, stack_sz);
1716 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1717 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1718 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1719 // the exception consists of creating the exception object & initializing it, initialization
1720 // will leave the VM via a JavaCall and then all locks must be unlocked).
1721 //
1722 // The thread is still suspended when we reach here. Thread must be explicit started
1723 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1724 // by calling Threads:add. The reason why this is not done here, is because the thread
1725 // object must be fully initialized (take a look at JVM_Start)
1726 }
1727
1728 JavaThread::~JavaThread() {
1729
1730 // JSR166 -- return the parker to the free list
1731 Parker::Release(_parker);
1732 _parker = NULL;
1733
1734 // Free any remaining previous UnrollBlock
1735 vframeArray* old_array = vframe_array_last();
1736
1737 if (old_array != NULL) {
1738 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1739 old_array->set_unroll_block(NULL);
1740 delete old_info;
1741 delete old_array;
1742 }
1743
1744 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1745 if (deferred != NULL) {
1746 // This can only happen if thread is destroyed before deoptimization occurs.
1747 assert(deferred->length() != 0, "empty array!");
1748 do {
1749 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1750 deferred->remove_at(0);
1751 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1752 delete dlv;
1753 } while (deferred->length() != 0);
1754 delete deferred;
1755 }
1756
1757 // All Java related clean up happens in exit
1758 ThreadSafepointState::destroy(this);
1759 if (_thread_stat != NULL) delete _thread_stat;
1760
1761 #if INCLUDE_JVMCI
1762 if (JVMCICounterSize > 0) {
1763 if (jvmci_counters_include(this)) {
1764 for (int i = 0; i < JVMCICounterSize; i++) {
1765 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1766 }
1767 }
1768 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1769 }
1770 #endif // INCLUDE_JVMCI
1771 }
1772
1773
1774 // The first routine called by a new Java thread
1775 void JavaThread::run() {
1776 // initialize thread-local alloc buffer related fields
1777 this->initialize_tlab();
1778
1779 // used to test validity of stack trace backs
1780 this->record_base_of_stack_pointer();
1781
1782 // Record real stack base and size.
1783 this->record_stack_base_and_size();
1784
1785 this->create_stack_guard_pages();
1786
1787 this->cache_global_variables();
1788
1789 // Thread is now sufficient initialized to be handled by the safepoint code as being
1790 // in the VM. Change thread state from _thread_new to _thread_in_vm
1791 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1792
1793 assert(JavaThread::current() == this, "sanity check");
1794 assert(!Thread::current()->owns_locks(), "sanity check");
1795
1796 DTRACE_THREAD_PROBE(start, this);
1797
1798 // This operation might block. We call that after all safepoint checks for a new thread has
1799 // been completed.
1800 this->set_active_handles(JNIHandleBlock::allocate_block());
1801
1802 if (JvmtiExport::should_post_thread_life()) {
1803 JvmtiExport::post_thread_start(this);
1804 }
1805
1806 EventThreadStart event;
1807 if (event.should_commit()) {
1808 event.set_thread(THREAD_TRACE_ID(this));
1809 event.commit();
1810 }
1811
1812 // We call another function to do the rest so we are sure that the stack addresses used
1813 // from there will be lower than the stack base just computed
1814 thread_main_inner();
1815
1816 // Note, thread is no longer valid at this point!
1817 }
1818
1819
1820 void JavaThread::thread_main_inner() {
1821 assert(JavaThread::current() == this, "sanity check");
1822 assert(this->threadObj() != NULL, "just checking");
1823
1824 // Execute thread entry point unless this thread has a pending exception
1825 // or has been stopped before starting.
1826 // Note: Due to JVM_StopThread we can have pending exceptions already!
1827 if (!this->has_pending_exception() &&
1828 !java_lang_Thread::is_stillborn(this->threadObj())) {
1829 {
1830 ResourceMark rm(this);
1831 this->set_native_thread_name(this->get_thread_name());
1832 }
1833 HandleMark hm(this);
1834 this->entry_point()(this, this);
1835 }
1836
1837 DTRACE_THREAD_PROBE(stop, this);
1838
1839 this->exit(false);
1840 this->smr_delete();
1841 }
1842
1843
1844 static void ensure_join(JavaThread* thread) {
1845 // We do not need to grab the Threads_lock, since we are operating on ourself.
1846 Handle threadObj(thread, thread->threadObj());
1847 assert(threadObj.not_null(), "java thread object must exist");
1848 ObjectLocker lock(threadObj, thread);
1849 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1850 thread->clear_pending_exception();
1851 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1852 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1853 // Clear the native thread instance - this makes isAlive return false and allows the join()
1854 // to complete once we've done the notify_all below
1855 java_lang_Thread::set_thread(threadObj(), NULL);
1856 lock.notify_all(thread);
1857 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1858 thread->clear_pending_exception();
1859 }
1860
1861
1862 // For any new cleanup additions, please check to see if they need to be applied to
1863 // cleanup_failed_attach_current_thread as well.
1864 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1865 assert(this == JavaThread::current(), "thread consistency check");
1866
1867 elapsedTimer _timer_exit_phase1;
1868 elapsedTimer _timer_exit_phase2;
1869 elapsedTimer _timer_exit_phase3;
1870 elapsedTimer _timer_exit_phase4;
1871
1872 if (log_is_enabled(Debug, os, thread, timer)) {
1873 _timer_exit_phase1.start();
1874 }
1875
1876 HandleMark hm(this);
1877 Handle uncaught_exception(this, this->pending_exception());
1878 this->clear_pending_exception();
1879 Handle threadObj(this, this->threadObj());
1880 assert(threadObj.not_null(), "Java thread object should be created");
1881
1882 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1883 {
1884 EXCEPTION_MARK;
1885
1886 CLEAR_PENDING_EXCEPTION;
1887 }
1888 if (!destroy_vm) {
1889 if (uncaught_exception.not_null()) {
1890 EXCEPTION_MARK;
1891 // Call method Thread.dispatchUncaughtException().
1892 Klass* thread_klass = SystemDictionary::Thread_klass();
1893 JavaValue result(T_VOID);
1894 JavaCalls::call_virtual(&result,
1895 threadObj, thread_klass,
1896 vmSymbols::dispatchUncaughtException_name(),
1897 vmSymbols::throwable_void_signature(),
1898 uncaught_exception,
1899 THREAD);
1900 if (HAS_PENDING_EXCEPTION) {
1901 ResourceMark rm(this);
1902 jio_fprintf(defaultStream::error_stream(),
1903 "\nException: %s thrown from the UncaughtExceptionHandler"
1904 " in thread \"%s\"\n",
1905 pending_exception()->klass()->external_name(),
1906 get_thread_name());
1907 CLEAR_PENDING_EXCEPTION;
1908 }
1909 }
1910
1911 // Called before the java thread exit since we want to read info
1912 // from java_lang_Thread object
1913 EventThreadEnd event;
1914 if (event.should_commit()) {
1915 event.set_thread(THREAD_TRACE_ID(this));
1916 event.commit();
1917 }
1918
1919 // Call after last event on thread
1920 EVENT_THREAD_EXIT(this);
1921
1922 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1923 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1924 // is deprecated anyhow.
1925 if (!is_Compiler_thread()) {
1926 int count = 3;
1927 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1928 EXCEPTION_MARK;
1929 JavaValue result(T_VOID);
1930 Klass* thread_klass = SystemDictionary::Thread_klass();
1931 JavaCalls::call_virtual(&result,
1932 threadObj, thread_klass,
1933 vmSymbols::exit_method_name(),
1934 vmSymbols::void_method_signature(),
1935 THREAD);
1936 CLEAR_PENDING_EXCEPTION;
1937 }
1938 }
1939 // notify JVMTI
1940 if (JvmtiExport::should_post_thread_life()) {
1941 JvmtiExport::post_thread_end(this);
1942 }
1943
1944 // We have notified the agents that we are exiting, before we go on,
1945 // we must check for a pending external suspend request and honor it
1946 // in order to not surprise the thread that made the suspend request.
1947 while (true) {
1948 {
1949 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1950 if (!is_external_suspend()) {
1951 set_terminated(_thread_exiting);
1952 ThreadService::current_thread_exiting(this);
1953 break;
1954 }
1955 // Implied else:
1956 // Things get a little tricky here. We have a pending external
1957 // suspend request, but we are holding the SR_lock so we
1958 // can't just self-suspend. So we temporarily drop the lock
1959 // and then self-suspend.
1960 }
1961
1962 ThreadBlockInVM tbivm(this);
1963 java_suspend_self();
1964
1965 // We're done with this suspend request, but we have to loop around
1966 // and check again. Eventually we will get SR_lock without a pending
1967 // external suspend request and will be able to mark ourselves as
1968 // exiting.
1969 }
1970 // no more external suspends are allowed at this point
1971 } else {
1972 // before_exit() has already posted JVMTI THREAD_END events
1973 }
1974
1975 if (log_is_enabled(Debug, os, thread, timer)) {
1976 _timer_exit_phase1.stop();
1977 _timer_exit_phase2.start();
1978 }
1979 // Notify waiters on thread object. This has to be done after exit() is called
1980 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1981 // group should have the destroyed bit set before waiters are notified).
1982 ensure_join(this);
1983 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1984
1985 if (log_is_enabled(Debug, os, thread, timer)) {
1986 _timer_exit_phase2.stop();
1987 _timer_exit_phase3.start();
1988 }
1989 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1990 // held by this thread must be released. The spec does not distinguish
1991 // between JNI-acquired and regular Java monitors. We can only see
1992 // regular Java monitors here if monitor enter-exit matching is broken.
1993 //
1994 // Optionally release any monitors for regular JavaThread exits. This
1995 // is provided as a work around for any bugs in monitor enter-exit
1996 // matching. This can be expensive so it is not enabled by default.
1997 //
1998 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1999 // ObjectSynchronizer::release_monitors_owned_by_thread().
2000 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) {
2001 // Sanity check even though JNI DetachCurrentThread() would have
2002 // returned JNI_ERR if there was a Java frame. JavaThread exit
2003 // should be done executing Java code by the time we get here.
2004 assert(!this->has_last_Java_frame(),
2005 "should not have a Java frame when detaching or exiting");
2006 ObjectSynchronizer::release_monitors_owned_by_thread(this);
2007 assert(!this->has_pending_exception(), "release_monitors should have cleared");
2008 }
2009
2010 // These things needs to be done while we are still a Java Thread. Make sure that thread
2011 // is in a consistent state, in case GC happens
2012 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
2013
2014 if (active_handles() != NULL) {
2015 JNIHandleBlock* block = active_handles();
2016 set_active_handles(NULL);
2017 JNIHandleBlock::release_block(block);
2018 }
2019
2020 if (free_handle_block() != NULL) {
2021 JNIHandleBlock* block = free_handle_block();
2022 set_free_handle_block(NULL);
2023 JNIHandleBlock::release_block(block);
2024 }
2025
2026 // These have to be removed while this is still a valid thread.
2027 remove_stack_guard_pages();
2028
2029 if (UseTLAB) {
2030 tlab().make_parsable(true); // retire TLAB
2031 }
2032
2033 if (JvmtiEnv::environments_might_exist()) {
2034 JvmtiExport::cleanup_thread(this);
2035 }
2036
2037 // We must flush any deferred card marks before removing a thread from
2038 // the list of active threads.
2039 Universe::heap()->flush_deferred_store_barrier(this);
2040 assert(deferred_card_mark().is_empty(), "Should have been flushed");
2041
2042 #if INCLUDE_ALL_GCS
2043 // We must flush the G1-related buffers before removing a thread
2044 // from the list of active threads. We must do this after any deferred
2045 // card marks have been flushed (above) so that any entries that are
2046 // added to the thread's dirty card queue as a result are not lost.
2047 if (UseG1GC || (UseShenandoahGC && (ShenandoahSATBBarrier || ShenandoahKeepAliveBarrier || ShenandoahStoreValEnqueueBarrier))) {
2048 flush_barrier_queues();
2049 }
2050 if (UseShenandoahGC && gclab() != NULL) {
2051 ShenandoahHeap::heap()->finalize_mutator_gclab(this);
2052 }
2053 #endif // INCLUDE_ALL_GCS
2054
2055 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2056 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2057 os::current_thread_id());
2058
2059 if (log_is_enabled(Debug, os, thread, timer)) {
2060 _timer_exit_phase3.stop();
2061 _timer_exit_phase4.start();
2062 }
2063 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2064 Threads::remove(this);
2065
2066 if (log_is_enabled(Debug, os, thread, timer)) {
2067 _timer_exit_phase4.stop();
2068 ResourceMark rm(this);
2069 log_debug(os, thread, timer)("name='%s'"
2070 ", exit-phase1=" JLONG_FORMAT
2071 ", exit-phase2=" JLONG_FORMAT
2072 ", exit-phase3=" JLONG_FORMAT
2073 ", exit-phase4=" JLONG_FORMAT,
2074 get_thread_name(),
2075 _timer_exit_phase1.milliseconds(),
2076 _timer_exit_phase2.milliseconds(),
2077 _timer_exit_phase3.milliseconds(),
2078 _timer_exit_phase4.milliseconds());
2079 }
2080 }
2081
2082 #if INCLUDE_ALL_GCS
2083 // Flush G1-related queues.
2084 void JavaThread::flush_barrier_queues() {
2085 satb_mark_queue().flush();
2086 dirty_card_queue().flush();
2087 }
2088
2089 void JavaThread::initialize_queues() {
2090 assert(!SafepointSynchronize::is_at_safepoint(),
2091 "we should not be at a safepoint");
2092
2093 SATBMarkQueue& satb_queue = satb_mark_queue();
2094 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
2095 // The SATB queue should have been constructed with its active
2096 // field set to false.
2097 assert(!satb_queue.is_active(), "SATB queue should not be active");
2098 assert(satb_queue.is_empty(), "SATB queue should be empty");
2099 // If we are creating the thread during a marking cycle, we should
2100 // set the active field of the SATB queue to true.
2101 if (satb_queue_set.is_active()) {
2102 satb_queue.set_active(true);
2103 }
2104
2105 DirtyCardQueue& dirty_queue = dirty_card_queue();
2106 // The dirty card queue should have been constructed with its
2107 // active field set to true.
2108 assert(dirty_queue.is_active(), "dirty card queue should be active");
2109
2110 _gc_state = _gc_state_global;
2111
2112 if (UseShenandoahGC) {
2113 ShenandoahHeap::heap()->initialize_gclab(this);
2114 }
2115 }
2116 #endif // INCLUDE_ALL_GCS
2117
2118 void JavaThread::cleanup_failed_attach_current_thread() {
2119 if (active_handles() != NULL) {
2120 JNIHandleBlock* block = active_handles();
2121 set_active_handles(NULL);
2122 JNIHandleBlock::release_block(block);
2123 }
2124
2125 if (free_handle_block() != NULL) {
2126 JNIHandleBlock* block = free_handle_block();
2127 set_free_handle_block(NULL);
2128 JNIHandleBlock::release_block(block);
2129 }
2130
2131 // These have to be removed while this is still a valid thread.
2132 remove_stack_guard_pages();
2133
2134 if (UseTLAB) {
2135 tlab().make_parsable(true); // retire TLAB, if any
2136 }
2137
2138 #if INCLUDE_ALL_GCS
2139 if (UseG1GC || (UseShenandoahGC && (ShenandoahSATBBarrier || ShenandoahKeepAliveBarrier || ShenandoahStoreValEnqueueBarrier))) {
2140 flush_barrier_queues();
2141 }
2142 if (UseShenandoahGC && gclab() != NULL) {
2143 gclab()->flush_and_retire_stats(ShenandoahHeap::heap()->mutator_gclab_stats());
2144 }
2145 #endif // INCLUDE_ALL_GCS
2146
2147 Threads::remove(this);
2148 this->smr_delete();
2149 }
2150
2151
2152
2153
2154 JavaThread* JavaThread::active() {
2155 Thread* thread = Thread::current();
2156 if (thread->is_Java_thread()) {
2157 return (JavaThread*) thread;
2158 } else {
2159 assert(thread->is_VM_thread(), "this must be a vm thread");
2160 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2161 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2162 assert(ret->is_Java_thread(), "must be a Java thread");
2163 return ret;
2164 }
2165 }
2166
2167 bool JavaThread::is_lock_owned(address adr) const {
2168 if (Thread::is_lock_owned(adr)) return true;
2169
2170 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2171 if (chunk->contains(adr)) return true;
2172 }
2173
2174 return false;
2175 }
2176
2177
2178 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2179 chunk->set_next(monitor_chunks());
2180 set_monitor_chunks(chunk);
2181 }
2182
2183 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2184 guarantee(monitor_chunks() != NULL, "must be non empty");
2185 if (monitor_chunks() == chunk) {
2186 set_monitor_chunks(chunk->next());
2187 } else {
2188 MonitorChunk* prev = monitor_chunks();
2189 while (prev->next() != chunk) prev = prev->next();
2190 prev->set_next(chunk->next());
2191 }
2192 }
2193
2194 // JVM support.
2195
2196 // Note: this function shouldn't block if it's called in
2197 // _thread_in_native_trans state (such as from
2198 // check_special_condition_for_native_trans()).
2199 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2200
2201 if (has_last_Java_frame() && has_async_condition()) {
2202 // If we are at a polling page safepoint (not a poll return)
2203 // then we must defer async exception because live registers
2204 // will be clobbered by the exception path. Poll return is
2205 // ok because the call we a returning from already collides
2206 // with exception handling registers and so there is no issue.
2207 // (The exception handling path kills call result registers but
2208 // this is ok since the exception kills the result anyway).
2209
2210 if (is_at_poll_safepoint()) {
2211 // if the code we are returning to has deoptimized we must defer
2212 // the exception otherwise live registers get clobbered on the
2213 // exception path before deoptimization is able to retrieve them.
2214 //
2215 RegisterMap map(this, false);
2216 frame caller_fr = last_frame().sender(&map);
2217 assert(caller_fr.is_compiled_frame(), "what?");
2218 if (caller_fr.is_deoptimized_frame()) {
2219 log_info(exceptions)("deferred async exception at compiled safepoint");
2220 return;
2221 }
2222 }
2223 }
2224
2225 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2226 if (condition == _no_async_condition) {
2227 // Conditions have changed since has_special_runtime_exit_condition()
2228 // was called:
2229 // - if we were here only because of an external suspend request,
2230 // then that was taken care of above (or cancelled) so we are done
2231 // - if we were here because of another async request, then it has
2232 // been cleared between the has_special_runtime_exit_condition()
2233 // and now so again we are done
2234 return;
2235 }
2236
2237 // Check for pending async. exception
2238 if (_pending_async_exception != NULL) {
2239 // Only overwrite an already pending exception, if it is not a threadDeath.
2240 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2241
2242 // We cannot call Exceptions::_throw(...) here because we cannot block
2243 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2244
2245 LogTarget(Info, exceptions) lt;
2246 if (lt.is_enabled()) {
2247 ResourceMark rm;
2248 LogStream ls(lt);
2249 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2250 if (has_last_Java_frame()) {
2251 frame f = last_frame();
2252 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2253 }
2254 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2255 }
2256 _pending_async_exception = NULL;
2257 clear_has_async_exception();
2258 }
2259 }
2260
2261 if (check_unsafe_error &&
2262 condition == _async_unsafe_access_error && !has_pending_exception()) {
2263 condition = _no_async_condition; // done
2264 switch (thread_state()) {
2265 case _thread_in_vm: {
2266 JavaThread* THREAD = this;
2267 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2268 }
2269 case _thread_in_native: {
2270 ThreadInVMfromNative tiv(this);
2271 JavaThread* THREAD = this;
2272 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2273 }
2274 case _thread_in_Java: {
2275 ThreadInVMfromJava tiv(this);
2276 JavaThread* THREAD = this;
2277 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2278 }
2279 default:
2280 ShouldNotReachHere();
2281 }
2282 }
2283
2284 assert(condition == _no_async_condition || has_pending_exception() ||
2285 (!check_unsafe_error && condition == _async_unsafe_access_error),
2286 "must have handled the async condition, if no exception");
2287 }
2288
2289 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2290 //
2291 // Check for pending external suspend. Internal suspend requests do
2292 // not use handle_special_runtime_exit_condition().
2293 // If JNIEnv proxies are allowed, don't self-suspend if the target
2294 // thread is not the current thread. In older versions of jdbx, jdbx
2295 // threads could call into the VM with another thread's JNIEnv so we
2296 // can be here operating on behalf of a suspended thread (4432884).
2297 bool do_self_suspend = is_external_suspend_with_lock();
2298 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2299 //
2300 // Because thread is external suspended the safepoint code will count
2301 // thread as at a safepoint. This can be odd because we can be here
2302 // as _thread_in_Java which would normally transition to _thread_blocked
2303 // at a safepoint. We would like to mark the thread as _thread_blocked
2304 // before calling java_suspend_self like all other callers of it but
2305 // we must then observe proper safepoint protocol. (We can't leave
2306 // _thread_blocked with a safepoint in progress). However we can be
2307 // here as _thread_in_native_trans so we can't use a normal transition
2308 // constructor/destructor pair because they assert on that type of
2309 // transition. We could do something like:
2310 //
2311 // JavaThreadState state = thread_state();
2312 // set_thread_state(_thread_in_vm);
2313 // {
2314 // ThreadBlockInVM tbivm(this);
2315 // java_suspend_self()
2316 // }
2317 // set_thread_state(_thread_in_vm_trans);
2318 // if (safepoint) block;
2319 // set_thread_state(state);
2320 //
2321 // but that is pretty messy. Instead we just go with the way the
2322 // code has worked before and note that this is the only path to
2323 // java_suspend_self that doesn't put the thread in _thread_blocked
2324 // mode.
2325
2326 frame_anchor()->make_walkable(this);
2327 java_suspend_self();
2328
2329 // We might be here for reasons in addition to the self-suspend request
2330 // so check for other async requests.
2331 }
2332
2333 if (check_asyncs) {
2334 check_and_handle_async_exceptions();
2335 }
2336 #if INCLUDE_TRACE
2337 if (is_trace_suspend()) {
2338 TRACE_SUSPEND_THREAD(this);
2339 }
2340 #endif
2341 }
2342
2343 void JavaThread::send_thread_stop(oop java_throwable) {
2344 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2345 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2346 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2347
2348 // Do not throw asynchronous exceptions against the compiler thread
2349 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2350 if (!can_call_java()) return;
2351
2352 {
2353 // Actually throw the Throwable against the target Thread - however
2354 // only if there is no thread death exception installed already.
2355 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2356 // If the topmost frame is a runtime stub, then we are calling into
2357 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2358 // must deoptimize the caller before continuing, as the compiled exception handler table
2359 // may not be valid
2360 if (has_last_Java_frame()) {
2361 frame f = last_frame();
2362 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2363 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2364 RegisterMap reg_map(this, UseBiasedLocking);
2365 frame compiled_frame = f.sender(®_map);
2366 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2367 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2368 }
2369 }
2370 }
2371
2372 // Set async. pending exception in thread.
2373 set_pending_async_exception(java_throwable);
2374
2375 if (log_is_enabled(Info, exceptions)) {
2376 ResourceMark rm;
2377 log_info(exceptions)("Pending Async. exception installed of type: %s",
2378 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2379 }
2380 // for AbortVMOnException flag
2381 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2382 }
2383 }
2384
2385
2386 // Interrupt thread so it will wake up from a potential wait()
2387 Thread::interrupt(this);
2388 }
2389
2390 // External suspension mechanism.
2391 //
2392 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2393 // to any VM_locks and it is at a transition
2394 // Self-suspension will happen on the transition out of the vm.
2395 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2396 //
2397 // Guarantees on return:
2398 // + Target thread will not execute any new bytecode (that's why we need to
2399 // force a safepoint)
2400 // + Target thread will not enter any new monitors
2401 //
2402 void JavaThread::java_suspend() {
2403 ThreadsListHandle tlh;
2404 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2405 return;
2406 }
2407
2408 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2409 if (!is_external_suspend()) {
2410 // a racing resume has cancelled us; bail out now
2411 return;
2412 }
2413
2414 // suspend is done
2415 uint32_t debug_bits = 0;
2416 // Warning: is_ext_suspend_completed() may temporarily drop the
2417 // SR_lock to allow the thread to reach a stable thread state if
2418 // it is currently in a transient thread state.
2419 if (is_ext_suspend_completed(false /* !called_by_wait */,
2420 SuspendRetryDelay, &debug_bits)) {
2421 return;
2422 }
2423 }
2424
2425 VM_ThreadSuspend vm_suspend;
2426 VMThread::execute(&vm_suspend);
2427 }
2428
2429 // Part II of external suspension.
2430 // A JavaThread self suspends when it detects a pending external suspend
2431 // request. This is usually on transitions. It is also done in places
2432 // where continuing to the next transition would surprise the caller,
2433 // e.g., monitor entry.
2434 //
2435 // Returns the number of times that the thread self-suspended.
2436 //
2437 // Note: DO NOT call java_suspend_self() when you just want to block current
2438 // thread. java_suspend_self() is the second stage of cooperative
2439 // suspension for external suspend requests and should only be used
2440 // to complete an external suspend request.
2441 //
2442 int JavaThread::java_suspend_self() {
2443 int ret = 0;
2444
2445 // we are in the process of exiting so don't suspend
2446 if (is_exiting()) {
2447 clear_external_suspend();
2448 return ret;
2449 }
2450
2451 assert(_anchor.walkable() ||
2452 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2453 "must have walkable stack");
2454
2455 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2456
2457 assert(!this->is_ext_suspended(),
2458 "a thread trying to self-suspend should not already be suspended");
2459
2460 if (this->is_suspend_equivalent()) {
2461 // If we are self-suspending as a result of the lifting of a
2462 // suspend equivalent condition, then the suspend_equivalent
2463 // flag is not cleared until we set the ext_suspended flag so
2464 // that wait_for_ext_suspend_completion() returns consistent
2465 // results.
2466 this->clear_suspend_equivalent();
2467 }
2468
2469 // A racing resume may have cancelled us before we grabbed SR_lock
2470 // above. Or another external suspend request could be waiting for us
2471 // by the time we return from SR_lock()->wait(). The thread
2472 // that requested the suspension may already be trying to walk our
2473 // stack and if we return now, we can change the stack out from under
2474 // it. This would be a "bad thing (TM)" and cause the stack walker
2475 // to crash. We stay self-suspended until there are no more pending
2476 // external suspend requests.
2477 while (is_external_suspend()) {
2478 ret++;
2479 this->set_ext_suspended();
2480
2481 // _ext_suspended flag is cleared by java_resume()
2482 while (is_ext_suspended()) {
2483 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2484 }
2485 }
2486
2487 return ret;
2488 }
2489
2490 #ifdef ASSERT
2491 // verify the JavaThread has not yet been published in the Threads::list, and
2492 // hence doesn't need protection from concurrent access at this stage
2493 void JavaThread::verify_not_published() {
2494 ThreadsListHandle tlh;
2495 assert(!tlh.includes(this), "JavaThread shouldn't have been published yet!");
2496 }
2497 #endif
2498
2499 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2500 // progress or when _suspend_flags is non-zero.
2501 // Current thread needs to self-suspend if there is a suspend request and/or
2502 // block if a safepoint is in progress.
2503 // Async exception ISN'T checked.
2504 // Note only the ThreadInVMfromNative transition can call this function
2505 // directly and when thread state is _thread_in_native_trans
2506 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2507 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2508
2509 JavaThread *curJT = JavaThread::current();
2510 bool do_self_suspend = thread->is_external_suspend();
2511
2512 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2513
2514 // If JNIEnv proxies are allowed, don't self-suspend if the target
2515 // thread is not the current thread. In older versions of jdbx, jdbx
2516 // threads could call into the VM with another thread's JNIEnv so we
2517 // can be here operating on behalf of a suspended thread (4432884).
2518 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2519 JavaThreadState state = thread->thread_state();
2520
2521 // We mark this thread_blocked state as a suspend-equivalent so
2522 // that a caller to is_ext_suspend_completed() won't be confused.
2523 // The suspend-equivalent state is cleared by java_suspend_self().
2524 thread->set_suspend_equivalent();
2525
2526 // If the safepoint code sees the _thread_in_native_trans state, it will
2527 // wait until the thread changes to other thread state. There is no
2528 // guarantee on how soon we can obtain the SR_lock and complete the
2529 // self-suspend request. It would be a bad idea to let safepoint wait for
2530 // too long. Temporarily change the state to _thread_blocked to
2531 // let the VM thread know that this thread is ready for GC. The problem
2532 // of changing thread state is that safepoint could happen just after
2533 // java_suspend_self() returns after being resumed, and VM thread will
2534 // see the _thread_blocked state. We must check for safepoint
2535 // after restoring the state and make sure we won't leave while a safepoint
2536 // is in progress.
2537 thread->set_thread_state(_thread_blocked);
2538 thread->java_suspend_self();
2539 thread->set_thread_state(state);
2540
2541 InterfaceSupport::serialize_thread_state_with_handler(thread);
2542 }
2543
2544 SafepointMechanism::block_if_requested(curJT);
2545
2546 if (thread->is_deopt_suspend()) {
2547 thread->clear_deopt_suspend();
2548 RegisterMap map(thread, false);
2549 frame f = thread->last_frame();
2550 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2551 f = f.sender(&map);
2552 }
2553 if (f.id() == thread->must_deopt_id()) {
2554 thread->clear_must_deopt_id();
2555 f.deoptimize(thread);
2556 } else {
2557 fatal("missed deoptimization!");
2558 }
2559 }
2560 #if INCLUDE_TRACE
2561 if (thread->is_trace_suspend()) {
2562 TRACE_SUSPEND_THREAD(thread);
2563 }
2564 #endif
2565 }
2566
2567 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2568 // progress or when _suspend_flags is non-zero.
2569 // Current thread needs to self-suspend if there is a suspend request and/or
2570 // block if a safepoint is in progress.
2571 // Also check for pending async exception (not including unsafe access error).
2572 // Note only the native==>VM/Java barriers can call this function and when
2573 // thread state is _thread_in_native_trans.
2574 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2575 check_safepoint_and_suspend_for_native_trans(thread);
2576
2577 if (thread->has_async_exception()) {
2578 // We are in _thread_in_native_trans state, don't handle unsafe
2579 // access error since that may block.
2580 thread->check_and_handle_async_exceptions(false);
2581 }
2582 }
2583
2584 // This is a variant of the normal
2585 // check_special_condition_for_native_trans with slightly different
2586 // semantics for use by critical native wrappers. It does all the
2587 // normal checks but also performs the transition back into
2588 // thread_in_Java state. This is required so that critical natives
2589 // can potentially block and perform a GC if they are the last thread
2590 // exiting the GCLocker.
2591 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2592 check_special_condition_for_native_trans(thread);
2593
2594 // Finish the transition
2595 thread->set_thread_state(_thread_in_Java);
2596
2597 if (thread->do_critical_native_unlock()) {
2598 ThreadInVMfromJavaNoAsyncException tiv(thread);
2599 GCLocker::unlock_critical(thread);
2600 thread->clear_critical_native_unlock();
2601 }
2602 }
2603
2604 // We need to guarantee the Threads_lock here, since resumes are not
2605 // allowed during safepoint synchronization
2606 // Can only resume from an external suspension
2607 void JavaThread::java_resume() {
2608 assert_locked_or_safepoint(Threads_lock);
2609
2610 // Sanity check: thread is gone, has started exiting or the thread
2611 // was not externally suspended.
2612 ThreadsListHandle tlh;
2613 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2614 return;
2615 }
2616
2617 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2618
2619 clear_external_suspend();
2620
2621 if (is_ext_suspended()) {
2622 clear_ext_suspended();
2623 SR_lock()->notify_all();
2624 }
2625 }
2626
2627 size_t JavaThread::_stack_red_zone_size = 0;
2628 size_t JavaThread::_stack_yellow_zone_size = 0;
2629 size_t JavaThread::_stack_reserved_zone_size = 0;
2630 size_t JavaThread::_stack_shadow_zone_size = 0;
2631
2632 void JavaThread::create_stack_guard_pages() {
2633 if (!os::uses_stack_guard_pages() ||
2634 _stack_guard_state != stack_guard_unused ||
2635 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2636 log_info(os, thread)("Stack guard page creation for thread "
2637 UINTX_FORMAT " disabled", os::current_thread_id());
2638 return;
2639 }
2640 address low_addr = stack_end();
2641 size_t len = stack_guard_zone_size();
2642
2643 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2644 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2645
2646 int must_commit = os::must_commit_stack_guard_pages();
2647 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2648
2649 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2650 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2651 return;
2652 }
2653
2654 if (os::guard_memory((char *) low_addr, len)) {
2655 _stack_guard_state = stack_guard_enabled;
2656 } else {
2657 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2658 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2659 if (os::uncommit_memory((char *) low_addr, len)) {
2660 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2661 }
2662 return;
2663 }
2664
2665 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2666 PTR_FORMAT "-" PTR_FORMAT ".",
2667 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2668 }
2669
2670 void JavaThread::remove_stack_guard_pages() {
2671 assert(Thread::current() == this, "from different thread");
2672 if (_stack_guard_state == stack_guard_unused) return;
2673 address low_addr = stack_end();
2674 size_t len = stack_guard_zone_size();
2675
2676 if (os::must_commit_stack_guard_pages()) {
2677 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2678 _stack_guard_state = stack_guard_unused;
2679 } else {
2680 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2681 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2682 return;
2683 }
2684 } else {
2685 if (_stack_guard_state == stack_guard_unused) return;
2686 if (os::unguard_memory((char *) low_addr, len)) {
2687 _stack_guard_state = stack_guard_unused;
2688 } else {
2689 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2690 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2691 return;
2692 }
2693 }
2694
2695 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2696 PTR_FORMAT "-" PTR_FORMAT ".",
2697 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2698 }
2699
2700 void JavaThread::enable_stack_reserved_zone() {
2701 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2702 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2703
2704 // The base notation is from the stack's point of view, growing downward.
2705 // We need to adjust it to work correctly with guard_memory()
2706 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2707
2708 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2709 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2710
2711 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2712 _stack_guard_state = stack_guard_enabled;
2713 } else {
2714 warning("Attempt to guard stack reserved zone failed.");
2715 }
2716 enable_register_stack_guard();
2717 }
2718
2719 void JavaThread::disable_stack_reserved_zone() {
2720 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2721 assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled");
2722
2723 // Simply return if called for a thread that does not use guard pages.
2724 if (_stack_guard_state == stack_guard_unused) return;
2725
2726 // The base notation is from the stack's point of view, growing downward.
2727 // We need to adjust it to work correctly with guard_memory()
2728 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2729
2730 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2731 _stack_guard_state = stack_guard_reserved_disabled;
2732 } else {
2733 warning("Attempt to unguard stack reserved zone failed.");
2734 }
2735 disable_register_stack_guard();
2736 }
2737
2738 void JavaThread::enable_stack_yellow_reserved_zone() {
2739 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2740 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2741
2742 // The base notation is from the stacks point of view, growing downward.
2743 // We need to adjust it to work correctly with guard_memory()
2744 address base = stack_red_zone_base();
2745
2746 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2747 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2748
2749 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2750 _stack_guard_state = stack_guard_enabled;
2751 } else {
2752 warning("Attempt to guard stack yellow zone failed.");
2753 }
2754 enable_register_stack_guard();
2755 }
2756
2757 void JavaThread::disable_stack_yellow_reserved_zone() {
2758 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2759 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2760
2761 // Simply return if called for a thread that does not use guard pages.
2762 if (_stack_guard_state == stack_guard_unused) return;
2763
2764 // The base notation is from the stacks point of view, growing downward.
2765 // We need to adjust it to work correctly with guard_memory()
2766 address base = stack_red_zone_base();
2767
2768 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2769 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2770 } else {
2771 warning("Attempt to unguard stack yellow zone failed.");
2772 }
2773 disable_register_stack_guard();
2774 }
2775
2776 void JavaThread::enable_stack_red_zone() {
2777 // The base notation is from the stacks point of view, growing downward.
2778 // We need to adjust it to work correctly with guard_memory()
2779 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2780 address base = stack_red_zone_base() - stack_red_zone_size();
2781
2782 guarantee(base < stack_base(), "Error calculating stack red zone");
2783 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2784
2785 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2786 warning("Attempt to guard stack red zone failed.");
2787 }
2788 }
2789
2790 void JavaThread::disable_stack_red_zone() {
2791 // The base notation is from the stacks point of view, growing downward.
2792 // We need to adjust it to work correctly with guard_memory()
2793 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2794 address base = stack_red_zone_base() - stack_red_zone_size();
2795 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2796 warning("Attempt to unguard stack red zone failed.");
2797 }
2798 }
2799
2800 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2801 // ignore is there is no stack
2802 if (!has_last_Java_frame()) return;
2803 // traverse the stack frames. Starts from top frame.
2804 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2805 frame* fr = fst.current();
2806 f(fr, fst.register_map());
2807 }
2808 }
2809
2810
2811 #ifndef PRODUCT
2812 // Deoptimization
2813 // Function for testing deoptimization
2814 void JavaThread::deoptimize() {
2815 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2816 StackFrameStream fst(this, UseBiasedLocking);
2817 bool deopt = false; // Dump stack only if a deopt actually happens.
2818 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2819 // Iterate over all frames in the thread and deoptimize
2820 for (; !fst.is_done(); fst.next()) {
2821 if (fst.current()->can_be_deoptimized()) {
2822
2823 if (only_at) {
2824 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2825 // consists of comma or carriage return separated numbers so
2826 // search for the current bci in that string.
2827 address pc = fst.current()->pc();
2828 nmethod* nm = (nmethod*) fst.current()->cb();
2829 ScopeDesc* sd = nm->scope_desc_at(pc);
2830 char buffer[8];
2831 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2832 size_t len = strlen(buffer);
2833 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2834 while (found != NULL) {
2835 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2836 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2837 // Check that the bci found is bracketed by terminators.
2838 break;
2839 }
2840 found = strstr(found + 1, buffer);
2841 }
2842 if (!found) {
2843 continue;
2844 }
2845 }
2846
2847 if (DebugDeoptimization && !deopt) {
2848 deopt = true; // One-time only print before deopt
2849 tty->print_cr("[BEFORE Deoptimization]");
2850 trace_frames();
2851 trace_stack();
2852 }
2853 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2854 }
2855 }
2856
2857 if (DebugDeoptimization && deopt) {
2858 tty->print_cr("[AFTER Deoptimization]");
2859 trace_frames();
2860 }
2861 }
2862
2863
2864 // Make zombies
2865 void JavaThread::make_zombies() {
2866 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2867 if (fst.current()->can_be_deoptimized()) {
2868 // it is a Java nmethod
2869 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2870 nm->make_not_entrant();
2871 }
2872 }
2873 }
2874 #endif // PRODUCT
2875
2876
2877 void JavaThread::deoptimized_wrt_marked_nmethods() {
2878 if (!has_last_Java_frame()) return;
2879 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2880 StackFrameStream fst(this, UseBiasedLocking);
2881 for (; !fst.is_done(); fst.next()) {
2882 if (fst.current()->should_be_deoptimized()) {
2883 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2884 }
2885 }
2886 }
2887
2888
2889 // If the caller is a NamedThread, then remember, in the current scope,
2890 // the given JavaThread in its _processed_thread field.
2891 class RememberProcessedThread: public StackObj {
2892 NamedThread* _cur_thr;
2893 public:
2894 RememberProcessedThread(JavaThread* jthr) {
2895 Thread* thread = Thread::current();
2896 if (thread->is_Named_thread()) {
2897 _cur_thr = (NamedThread *)thread;
2898 _cur_thr->set_processed_thread(jthr);
2899 } else {
2900 _cur_thr = NULL;
2901 }
2902 }
2903
2904 ~RememberProcessedThread() {
2905 if (_cur_thr) {
2906 _cur_thr->set_processed_thread(NULL);
2907 }
2908 }
2909 };
2910
2911 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2912 // Verify that the deferred card marks have been flushed.
2913 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2914
2915 // Traverse the GCHandles
2916 Thread::oops_do(f, cf);
2917
2918 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);)
2919
2920 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2921 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2922
2923 if (has_last_Java_frame()) {
2924 // Record JavaThread to GC thread
2925 RememberProcessedThread rpt(this);
2926
2927 // Traverse the privileged stack
2928 if (_privileged_stack_top != NULL) {
2929 _privileged_stack_top->oops_do(f);
2930 }
2931
2932 // traverse the registered growable array
2933 if (_array_for_gc != NULL) {
2934 for (int index = 0; index < _array_for_gc->length(); index++) {
2935 f->do_oop(_array_for_gc->adr_at(index));
2936 }
2937 }
2938
2939 // Traverse the monitor chunks
2940 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2941 chunk->oops_do(f);
2942 }
2943
2944 // Traverse the execution stack
2945 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2946 fst.current()->oops_do(f, cf, fst.register_map());
2947 }
2948 }
2949
2950 // callee_target is never live across a gc point so NULL it here should
2951 // it still contain a methdOop.
2952
2953 set_callee_target(NULL);
2954
2955 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2956 // If we have deferred set_locals there might be oops waiting to be
2957 // written
2958 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2959 if (list != NULL) {
2960 for (int i = 0; i < list->length(); i++) {
2961 list->at(i)->oops_do(f);
2962 }
2963 }
2964
2965 // Traverse instance variables at the end since the GC may be moving things
2966 // around using this function
2967 f->do_oop((oop*) &_threadObj);
2968 f->do_oop((oop*) &_vm_result);
2969 f->do_oop((oop*) &_exception_oop);
2970 f->do_oop((oop*) &_pending_async_exception);
2971
2972 if (jvmti_thread_state() != NULL) {
2973 jvmti_thread_state()->oops_do(f);
2974 }
2975 }
2976
2977 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2978 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2979 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2980
2981 if (has_last_Java_frame()) {
2982 // Traverse the execution stack
2983 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2984 fst.current()->nmethods_do(cf);
2985 }
2986 }
2987 }
2988
2989 void JavaThread::metadata_do(void f(Metadata*)) {
2990 if (has_last_Java_frame()) {
2991 // Traverse the execution stack to call f() on the methods in the stack
2992 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2993 fst.current()->metadata_do(f);
2994 }
2995 } else if (is_Compiler_thread()) {
2996 // need to walk ciMetadata in current compile tasks to keep alive.
2997 CompilerThread* ct = (CompilerThread*)this;
2998 if (ct->env() != NULL) {
2999 ct->env()->metadata_do(f);
3000 }
3001 CompileTask* task = ct->task();
3002 if (task != NULL) {
3003 task->metadata_do(f);
3004 }
3005 }
3006 }
3007
3008 // Printing
3009 const char* _get_thread_state_name(JavaThreadState _thread_state) {
3010 switch (_thread_state) {
3011 case _thread_uninitialized: return "_thread_uninitialized";
3012 case _thread_new: return "_thread_new";
3013 case _thread_new_trans: return "_thread_new_trans";
3014 case _thread_in_native: return "_thread_in_native";
3015 case _thread_in_native_trans: return "_thread_in_native_trans";
3016 case _thread_in_vm: return "_thread_in_vm";
3017 case _thread_in_vm_trans: return "_thread_in_vm_trans";
3018 case _thread_in_Java: return "_thread_in_Java";
3019 case _thread_in_Java_trans: return "_thread_in_Java_trans";
3020 case _thread_blocked: return "_thread_blocked";
3021 case _thread_blocked_trans: return "_thread_blocked_trans";
3022 default: return "unknown thread state";
3023 }
3024 }
3025
3026 #ifndef PRODUCT
3027 void JavaThread::print_thread_state_on(outputStream *st) const {
3028 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
3029 };
3030 void JavaThread::print_thread_state() const {
3031 print_thread_state_on(tty);
3032 }
3033 #endif // PRODUCT
3034
3035 // Called by Threads::print() for VM_PrintThreads operation
3036 void JavaThread::print_on(outputStream *st) const {
3037 st->print_raw("\"");
3038 st->print_raw(get_thread_name());
3039 st->print_raw("\" ");
3040 oop thread_oop = threadObj();
3041 if (thread_oop != NULL) {
3042 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
3043 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
3044 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
3045 }
3046 Thread::print_on(st);
3047 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
3048 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
3049 if (thread_oop != NULL) {
3050 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
3051 }
3052 #ifndef PRODUCT
3053 print_thread_state_on(st);
3054 _safepoint_state->print_on(st);
3055 #endif // PRODUCT
3056 if (is_Compiler_thread()) {
3057 CompileTask *task = ((CompilerThread*)this)->task();
3058 if (task != NULL) {
3059 st->print(" Compiling: ");
3060 task->print(st, NULL, true, false);
3061 } else {
3062 st->print(" No compile task");
3063 }
3064 st->cr();
3065 }
3066 }
3067
3068 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
3069 st->print("%s", get_thread_name_string(buf, buflen));
3070 }
3071
3072 // Called by fatal error handler. The difference between this and
3073 // JavaThread::print() is that we can't grab lock or allocate memory.
3074 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
3075 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
3076 oop thread_obj = threadObj();
3077 if (thread_obj != NULL) {
3078 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
3079 }
3080 st->print(" [");
3081 st->print("%s", _get_thread_state_name(_thread_state));
3082 if (osthread()) {
3083 st->print(", id=%d", osthread()->thread_id());
3084 }
3085 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
3086 p2i(stack_end()), p2i(stack_base()));
3087 st->print("]");
3088
3089 if (_threads_hazard_ptr != NULL) {
3090 st->print(" _threads_hazard_ptr=" INTPTR_FORMAT, p2i(_threads_hazard_ptr));
3091 }
3092 if (_nested_threads_hazard_ptr != NULL) {
3093 print_nested_threads_hazard_ptrs_on(st);
3094 }
3095 return;
3096 }
3097
3098 // Verification
3099
3100 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3101
3102 void JavaThread::verify() {
3103 // Verify oops in the thread.
3104 oops_do(&VerifyOopClosure::verify_oop, NULL);
3105
3106 // Verify the stack frames.
3107 frames_do(frame_verify);
3108 }
3109
3110 // CR 6300358 (sub-CR 2137150)
3111 // Most callers of this method assume that it can't return NULL but a
3112 // thread may not have a name whilst it is in the process of attaching to
3113 // the VM - see CR 6412693, and there are places where a JavaThread can be
3114 // seen prior to having it's threadObj set (eg JNI attaching threads and
3115 // if vm exit occurs during initialization). These cases can all be accounted
3116 // for such that this method never returns NULL.
3117 const char* JavaThread::get_thread_name() const {
3118 #ifdef ASSERT
3119 // early safepoints can hit while current thread does not yet have TLS
3120 if (!SafepointSynchronize::is_at_safepoint()) {
3121 Thread *cur = Thread::current();
3122 if (!(cur->is_Java_thread() && cur == this)) {
3123 // Current JavaThreads are allowed to get their own name without
3124 // the Threads_lock.
3125 assert_locked_or_safepoint(Threads_lock);
3126 }
3127 }
3128 #endif // ASSERT
3129 return get_thread_name_string();
3130 }
3131
3132 // Returns a non-NULL representation of this thread's name, or a suitable
3133 // descriptive string if there is no set name
3134 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3135 const char* name_str;
3136 oop thread_obj = threadObj();
3137 if (thread_obj != NULL) {
3138 oop name = java_lang_Thread::name(thread_obj);
3139 if (name != NULL) {
3140 if (buf == NULL) {
3141 name_str = java_lang_String::as_utf8_string(name);
3142 } else {
3143 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3144 }
3145 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3146 name_str = "<no-name - thread is attaching>";
3147 } else {
3148 name_str = Thread::name();
3149 }
3150 } else {
3151 name_str = Thread::name();
3152 }
3153 assert(name_str != NULL, "unexpected NULL thread name");
3154 return name_str;
3155 }
3156
3157
3158 const char* JavaThread::get_threadgroup_name() const {
3159 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3160 oop thread_obj = threadObj();
3161 if (thread_obj != NULL) {
3162 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3163 if (thread_group != NULL) {
3164 // ThreadGroup.name can be null
3165 return java_lang_ThreadGroup::name(thread_group);
3166 }
3167 }
3168 return NULL;
3169 }
3170
3171 const char* JavaThread::get_parent_name() const {
3172 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3173 oop thread_obj = threadObj();
3174 if (thread_obj != NULL) {
3175 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3176 if (thread_group != NULL) {
3177 oop parent = java_lang_ThreadGroup::parent(thread_group);
3178 if (parent != NULL) {
3179 // ThreadGroup.name can be null
3180 return java_lang_ThreadGroup::name(parent);
3181 }
3182 }
3183 }
3184 return NULL;
3185 }
3186
3187 ThreadPriority JavaThread::java_priority() const {
3188 oop thr_oop = threadObj();
3189 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3190 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3191 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3192 return priority;
3193 }
3194
3195 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3196
3197 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3198 // Link Java Thread object <-> C++ Thread
3199
3200 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3201 // and put it into a new Handle. The Handle "thread_oop" can then
3202 // be used to pass the C++ thread object to other methods.
3203
3204 // Set the Java level thread object (jthread) field of the
3205 // new thread (a JavaThread *) to C++ thread object using the
3206 // "thread_oop" handle.
3207
3208 // Set the thread field (a JavaThread *) of the
3209 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3210
3211 Handle thread_oop(Thread::current(),
3212 JNIHandles::resolve_non_null(jni_thread));
3213 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3214 "must be initialized");
3215 set_threadObj(thread_oop());
3216 java_lang_Thread::set_thread(thread_oop(), this);
3217
3218 if (prio == NoPriority) {
3219 prio = java_lang_Thread::priority(thread_oop());
3220 assert(prio != NoPriority, "A valid priority should be present");
3221 }
3222
3223 // Push the Java priority down to the native thread; needs Threads_lock
3224 Thread::set_priority(this, prio);
3225
3226 prepare_ext();
3227
3228 // Add the new thread to the Threads list and set it in motion.
3229 // We must have threads lock in order to call Threads::add.
3230 // It is crucial that we do not block before the thread is
3231 // added to the Threads list for if a GC happens, then the java_thread oop
3232 // will not be visited by GC.
3233 Threads::add(this);
3234 }
3235
3236 oop JavaThread::current_park_blocker() {
3237 // Support for JSR-166 locks
3238 oop thread_oop = threadObj();
3239 if (thread_oop != NULL &&
3240 JDK_Version::current().supports_thread_park_blocker()) {
3241 return java_lang_Thread::park_blocker(thread_oop);
3242 }
3243 return NULL;
3244 }
3245
3246
3247 void JavaThread::print_stack_on(outputStream* st) {
3248 if (!has_last_Java_frame()) return;
3249 ResourceMark rm;
3250 HandleMark hm;
3251
3252 RegisterMap reg_map(this);
3253 vframe* start_vf = last_java_vframe(®_map);
3254 int count = 0;
3255 for (vframe* f = start_vf; f; f = f->sender()) {
3256 if (f->is_java_frame()) {
3257 javaVFrame* jvf = javaVFrame::cast(f);
3258 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3259
3260 // Print out lock information
3261 if (JavaMonitorsInStackTrace) {
3262 jvf->print_lock_info_on(st, count);
3263 }
3264 } else {
3265 // Ignore non-Java frames
3266 }
3267
3268 // Bail-out case for too deep stacks
3269 count++;
3270 if (MaxJavaStackTraceDepth == count) return;
3271 }
3272 }
3273
3274
3275 // JVMTI PopFrame support
3276 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3277 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3278 if (in_bytes(size_in_bytes) != 0) {
3279 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3280 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3281 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3282 }
3283 }
3284
3285 void* JavaThread::popframe_preserved_args() {
3286 return _popframe_preserved_args;
3287 }
3288
3289 ByteSize JavaThread::popframe_preserved_args_size() {
3290 return in_ByteSize(_popframe_preserved_args_size);
3291 }
3292
3293 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3294 int sz = in_bytes(popframe_preserved_args_size());
3295 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3296 return in_WordSize(sz / wordSize);
3297 }
3298
3299 void JavaThread::popframe_free_preserved_args() {
3300 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3301 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3302 _popframe_preserved_args = NULL;
3303 _popframe_preserved_args_size = 0;
3304 }
3305
3306 #ifndef PRODUCT
3307
3308 void JavaThread::trace_frames() {
3309 tty->print_cr("[Describe stack]");
3310 int frame_no = 1;
3311 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3312 tty->print(" %d. ", frame_no++);
3313 fst.current()->print_value_on(tty, this);
3314 tty->cr();
3315 }
3316 }
3317
3318 class PrintAndVerifyOopClosure: public OopClosure {
3319 protected:
3320 template <class T> inline void do_oop_work(T* p) {
3321 oop obj = oopDesc::load_decode_heap_oop(p);
3322 if (obj == NULL) return;
3323 tty->print(INTPTR_FORMAT ": ", p2i(p));
3324 if (oopDesc::is_oop_or_null(obj)) {
3325 if (obj->is_objArray()) {
3326 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3327 } else {
3328 obj->print();
3329 }
3330 } else {
3331 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3332 }
3333 tty->cr();
3334 }
3335 public:
3336 virtual void do_oop(oop* p) { do_oop_work(p); }
3337 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3338 };
3339
3340
3341 static void oops_print(frame* f, const RegisterMap *map) {
3342 PrintAndVerifyOopClosure print;
3343 f->print_value();
3344 f->oops_do(&print, NULL, (RegisterMap*)map);
3345 }
3346
3347 // Print our all the locations that contain oops and whether they are
3348 // valid or not. This useful when trying to find the oldest frame
3349 // where an oop has gone bad since the frame walk is from youngest to
3350 // oldest.
3351 void JavaThread::trace_oops() {
3352 tty->print_cr("[Trace oops]");
3353 frames_do(oops_print);
3354 }
3355
3356
3357 #ifdef ASSERT
3358 // Print or validate the layout of stack frames
3359 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3360 ResourceMark rm;
3361 PRESERVE_EXCEPTION_MARK;
3362 FrameValues values;
3363 int frame_no = 0;
3364 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3365 fst.current()->describe(values, ++frame_no);
3366 if (depth == frame_no) break;
3367 }
3368 if (validate_only) {
3369 values.validate();
3370 } else {
3371 tty->print_cr("[Describe stack layout]");
3372 values.print(this);
3373 }
3374 }
3375 #endif
3376
3377 void JavaThread::trace_stack_from(vframe* start_vf) {
3378 ResourceMark rm;
3379 int vframe_no = 1;
3380 for (vframe* f = start_vf; f; f = f->sender()) {
3381 if (f->is_java_frame()) {
3382 javaVFrame::cast(f)->print_activation(vframe_no++);
3383 } else {
3384 f->print();
3385 }
3386 if (vframe_no > StackPrintLimit) {
3387 tty->print_cr("...<more frames>...");
3388 return;
3389 }
3390 }
3391 }
3392
3393
3394 void JavaThread::trace_stack() {
3395 if (!has_last_Java_frame()) return;
3396 ResourceMark rm;
3397 HandleMark hm;
3398 RegisterMap reg_map(this);
3399 trace_stack_from(last_java_vframe(®_map));
3400 }
3401
3402
3403 #endif // PRODUCT
3404
3405
3406 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3407 assert(reg_map != NULL, "a map must be given");
3408 frame f = last_frame();
3409 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3410 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3411 }
3412 return NULL;
3413 }
3414
3415
3416 Klass* JavaThread::security_get_caller_class(int depth) {
3417 vframeStream vfst(this);
3418 vfst.security_get_caller_frame(depth);
3419 if (!vfst.at_end()) {
3420 return vfst.method()->method_holder();
3421 }
3422 return NULL;
3423 }
3424
3425 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3426 assert(thread->is_Compiler_thread(), "must be compiler thread");
3427 CompileBroker::compiler_thread_loop();
3428 }
3429
3430 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3431 NMethodSweeper::sweeper_loop();
3432 }
3433
3434 // Create a CompilerThread
3435 CompilerThread::CompilerThread(CompileQueue* queue,
3436 CompilerCounters* counters)
3437 : JavaThread(&compiler_thread_entry) {
3438 _env = NULL;
3439 _log = NULL;
3440 _task = NULL;
3441 _queue = queue;
3442 _counters = counters;
3443 _buffer_blob = NULL;
3444 _compiler = NULL;
3445
3446 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3447 resource_area()->bias_to(mtCompiler);
3448
3449 #ifndef PRODUCT
3450 _ideal_graph_printer = NULL;
3451 #endif
3452 }
3453
3454 bool CompilerThread::can_call_java() const {
3455 return _compiler != NULL && _compiler->is_jvmci();
3456 }
3457
3458 // Create sweeper thread
3459 CodeCacheSweeperThread::CodeCacheSweeperThread()
3460 : JavaThread(&sweeper_thread_entry) {
3461 _scanned_compiled_method = NULL;
3462 }
3463
3464 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3465 JavaThread::oops_do(f, cf);
3466 if (_scanned_compiled_method != NULL && cf != NULL) {
3467 // Safepoints can occur when the sweeper is scanning an nmethod so
3468 // process it here to make sure it isn't unloaded in the middle of
3469 // a scan.
3470 cf->do_code_blob(_scanned_compiled_method);
3471 }
3472 }
3473
3474 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3475 JavaThread::nmethods_do(cf);
3476 if (_scanned_compiled_method != NULL && cf != NULL) {
3477 // Safepoints can occur when the sweeper is scanning an nmethod so
3478 // process it here to make sure it isn't unloaded in the middle of
3479 // a scan.
3480 cf->do_code_blob(_scanned_compiled_method);
3481 }
3482 }
3483
3484
3485 // ======= Threads ========
3486
3487 // The Threads class links together all active threads, and provides
3488 // operations over all threads. It is protected by the Threads_lock,
3489 // which is also used in other global contexts like safepointing.
3490 // ThreadsListHandles are used to safely perform operations on one
3491 // or more threads without the risk of the thread exiting during the
3492 // operation.
3493 //
3494 // Note: The Threads_lock is currently more widely used than we
3495 // would like. We are actively migrating Threads_lock uses to other
3496 // mechanisms in order to reduce Threads_lock contention.
3497
3498 JavaThread* Threads::_thread_list = NULL;
3499 int Threads::_number_of_threads = 0;
3500 int Threads::_number_of_non_daemon_threads = 0;
3501 int Threads::_return_code = 0;
3502 int Threads::_thread_claim_parity = 0;
3503 size_t JavaThread::_stack_size_at_create = 0;
3504
3505 #ifdef ASSERT
3506 bool Threads::_vm_complete = false;
3507 #endif
3508
3509 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3510 Prefetch::read((void*)addr, prefetch_interval);
3511 return *addr;
3512 }
3513
3514 // Possibly the ugliest for loop the world has seen. C++ does not allow
3515 // multiple types in the declaration section of the for loop. In this case
3516 // we are only dealing with pointers and hence can cast them. It looks ugly
3517 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3518 #define DO_JAVA_THREADS(LIST, X) \
3519 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3520 *MACRO_list = (JavaThread*)(LIST), \
3521 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3522 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3523 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3524 MACRO_current_p != MACRO_end; \
3525 MACRO_current_p++, \
3526 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3527
3528 // All JavaThreads
3529 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3530
3531 void Threads::java_threads_do(ThreadClosure* tc) {
3532 assert_locked_or_safepoint(Threads_lock);
3533 ALL_JAVA_THREADS(p) {
3534 tc->do_thread(p);
3535 }
3536 }
3537
3538 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3539 void Threads::threads_do(ThreadClosure* tc) {
3540 assert_locked_or_safepoint(Threads_lock);
3541 // ALL_JAVA_THREADS iterates through all JavaThreads
3542 ALL_JAVA_THREADS(p) {
3543 tc->do_thread(p);
3544 }
3545 // Someday we could have a table or list of all non-JavaThreads.
3546 // For now, just manually iterate through them.
3547 tc->do_thread(VMThread::vm_thread());
3548 Universe::heap()->gc_threads_do(tc);
3549 WatcherThread *wt = WatcherThread::watcher_thread();
3550 // Strictly speaking, the following NULL check isn't sufficient to make sure
3551 // the data for WatcherThread is still valid upon being examined. However,
3552 // considering that WatchThread terminates when the VM is on the way to
3553 // exit at safepoint, the chance of the above is extremely small. The right
3554 // way to prevent termination of WatcherThread would be to acquire
3555 // Terminator_lock, but we can't do that without violating the lock rank
3556 // checking in some cases.
3557 if (wt != NULL) {
3558 tc->do_thread(wt);
3559 }
3560
3561 // If CompilerThreads ever become non-JavaThreads, add them here
3562 }
3563
3564 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3565 int cp = Threads::thread_claim_parity();
3566 ALL_JAVA_THREADS(p) {
3567 if (p->claim_oops_do(is_par, cp)) {
3568 tc->do_thread(p);
3569 }
3570 }
3571 VMThread* vmt = VMThread::vm_thread();
3572 if (vmt->claim_oops_do(is_par, cp)) {
3573 tc->do_thread(vmt);
3574 }
3575 }
3576
3577 // The system initialization in the library has three phases.
3578 //
3579 // Phase 1: java.lang.System class initialization
3580 // java.lang.System is a primordial class loaded and initialized
3581 // by the VM early during startup. java.lang.System.<clinit>
3582 // only does registerNatives and keeps the rest of the class
3583 // initialization work later until thread initialization completes.
3584 //
3585 // System.initPhase1 initializes the system properties, the static
3586 // fields in, out, and err. Set up java signal handlers, OS-specific
3587 // system settings, and thread group of the main thread.
3588 static void call_initPhase1(TRAPS) {
3589 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3590 JavaValue result(T_VOID);
3591 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3592 vmSymbols::void_method_signature(), CHECK);
3593 }
3594
3595 // Phase 2. Module system initialization
3596 // This will initialize the module system. Only java.base classes
3597 // can be loaded until phase 2 completes.
3598 //
3599 // Call System.initPhase2 after the compiler initialization and jsr292
3600 // classes get initialized because module initialization runs a lot of java
3601 // code, that for performance reasons, should be compiled. Also, this will
3602 // enable the startup code to use lambda and other language features in this
3603 // phase and onward.
3604 //
3605 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3606 static void call_initPhase2(TRAPS) {
3607 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3608
3609 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3610
3611 JavaValue result(T_INT);
3612 JavaCallArguments args;
3613 args.push_int(DisplayVMOutputToStderr);
3614 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3615 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3616 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3617 if (result.get_jint() != JNI_OK) {
3618 vm_exit_during_initialization(); // no message or exception
3619 }
3620
3621 universe_post_module_init();
3622 }
3623
3624 // Phase 3. final setup - set security manager, system class loader and TCCL
3625 //
3626 // This will instantiate and set the security manager, set the system class
3627 // loader as well as the thread context class loader. The security manager
3628 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3629 // other modules or the application's classpath.
3630 static void call_initPhase3(TRAPS) {
3631 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3632 JavaValue result(T_VOID);
3633 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3634 vmSymbols::void_method_signature(), CHECK);
3635 }
3636
3637 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3638 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3639
3640 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3641 create_vm_init_libraries();
3642 }
3643
3644 initialize_class(vmSymbols::java_lang_String(), CHECK);
3645
3646 // Inject CompactStrings value after the static initializers for String ran.
3647 java_lang_String::set_compact_strings(CompactStrings);
3648
3649 // Initialize java_lang.System (needed before creating the thread)
3650 initialize_class(vmSymbols::java_lang_System(), CHECK);
3651 // The VM creates & returns objects of this class. Make sure it's initialized.
3652 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3653 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3654 Handle thread_group = create_initial_thread_group(CHECK);
3655 Universe::set_main_thread_group(thread_group());
3656 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3657 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3658 main_thread->set_threadObj(thread_object);
3659 // Set thread status to running since main thread has
3660 // been started and running.
3661 java_lang_Thread::set_thread_status(thread_object,
3662 java_lang_Thread::RUNNABLE);
3663
3664 // The VM creates objects of this class.
3665 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3666
3667 // The VM preresolves methods to these classes. Make sure that they get initialized
3668 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3669 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3670
3671 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3672 call_initPhase1(CHECK);
3673
3674 // get the Java runtime name after java.lang.System is initialized
3675 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3676 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3677
3678 // an instance of OutOfMemory exception has been allocated earlier
3679 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3680 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3681 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3682 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3683 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3684 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3685 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3686 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3687 }
3688
3689 void Threads::initialize_jsr292_core_classes(TRAPS) {
3690 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3691
3692 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3693 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3694 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3695 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3696 }
3697
3698 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3699 extern void JDK_Version_init();
3700
3701 // Preinitialize version info.
3702 VM_Version::early_initialize();
3703
3704 // Check version
3705 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3706
3707 // Initialize library-based TLS
3708 ThreadLocalStorage::init();
3709
3710 // Initialize the output stream module
3711 ostream_init();
3712
3713 // Process java launcher properties.
3714 Arguments::process_sun_java_launcher_properties(args);
3715
3716 // Initialize the os module
3717 os::init();
3718
3719 // Record VM creation timing statistics
3720 TraceVmCreationTime create_vm_timer;
3721 create_vm_timer.start();
3722
3723 // Initialize system properties.
3724 Arguments::init_system_properties();
3725
3726 // So that JDK version can be used as a discriminator when parsing arguments
3727 JDK_Version_init();
3728
3729 // Update/Initialize System properties after JDK version number is known
3730 Arguments::init_version_specific_system_properties();
3731
3732 // Make sure to initialize log configuration *before* parsing arguments
3733 LogConfiguration::initialize(create_vm_timer.begin_time());
3734
3735 // Parse arguments
3736 // Note: this internally calls os::init_container_support()
3737 jint parse_result = Arguments::parse(args);
3738 if (parse_result != JNI_OK) return parse_result;
3739
3740 os::init_before_ergo();
3741
3742 jint ergo_result = Arguments::apply_ergo();
3743 if (ergo_result != JNI_OK) return ergo_result;
3744
3745 // Final check of all ranges after ergonomics which may change values.
3746 if (!CommandLineFlagRangeList::check_ranges()) {
3747 return JNI_EINVAL;
3748 }
3749
3750 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3751 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3752 if (!constraint_result) {
3753 return JNI_EINVAL;
3754 }
3755
3756 CommandLineFlagWriteableList::mark_startup();
3757
3758 if (PauseAtStartup) {
3759 os::pause();
3760 }
3761
3762 HOTSPOT_VM_INIT_BEGIN();
3763
3764 // Timing (must come after argument parsing)
3765 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3766
3767 // Initialize the os module after parsing the args
3768 jint os_init_2_result = os::init_2();
3769 if (os_init_2_result != JNI_OK) return os_init_2_result;
3770
3771 SafepointMechanism::initialize();
3772
3773 jint adjust_after_os_result = Arguments::adjust_after_os();
3774 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3775
3776 // Initialize output stream logging
3777 ostream_init_log();
3778
3779 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3780 // Must be before create_vm_init_agents()
3781 if (Arguments::init_libraries_at_startup()) {
3782 convert_vm_init_libraries_to_agents();
3783 }
3784
3785 // Launch -agentlib/-agentpath and converted -Xrun agents
3786 if (Arguments::init_agents_at_startup()) {
3787 create_vm_init_agents();
3788 }
3789
3790 // Initialize Threads state
3791 _thread_list = NULL;
3792 _number_of_threads = 0;
3793 _number_of_non_daemon_threads = 0;
3794
3795 // Initialize global data structures and create system classes in heap
3796 vm_init_globals();
3797
3798 #if INCLUDE_JVMCI
3799 if (JVMCICounterSize > 0) {
3800 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3801 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3802 } else {
3803 JavaThread::_jvmci_old_thread_counters = NULL;
3804 }
3805 #endif // INCLUDE_JVMCI
3806
3807 // Attach the main thread to this os thread
3808 JavaThread* main_thread = new JavaThread();
3809 main_thread->set_thread_state(_thread_in_vm);
3810 main_thread->initialize_thread_current();
3811 // must do this before set_active_handles
3812 main_thread->record_stack_base_and_size();
3813 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3814
3815 if (!main_thread->set_as_starting_thread()) {
3816 vm_shutdown_during_initialization(
3817 "Failed necessary internal allocation. Out of swap space");
3818 main_thread->smr_delete();
3819 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3820 return JNI_ENOMEM;
3821 }
3822
3823 // Enable guard page *after* os::create_main_thread(), otherwise it would
3824 // crash Linux VM, see notes in os_linux.cpp.
3825 main_thread->create_stack_guard_pages();
3826
3827 // Initialize Java-Level synchronization subsystem
3828 ObjectMonitor::Initialize();
3829
3830 // Initialize global modules
3831 jint status = init_globals();
3832 if (status != JNI_OK) {
3833 main_thread->smr_delete();
3834 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3835 return status;
3836 }
3837
3838 if (TRACE_INITIALIZE() != JNI_OK) {
3839 vm_exit_during_initialization("Failed to initialize tracing backend");
3840 }
3841
3842 // Should be done after the heap is fully created
3843 main_thread->cache_global_variables();
3844
3845 HandleMark hm;
3846
3847 { MutexLocker mu(Threads_lock);
3848 Threads::add(main_thread);
3849 }
3850
3851 // Any JVMTI raw monitors entered in onload will transition into
3852 // real raw monitor. VM is setup enough here for raw monitor enter.
3853 JvmtiExport::transition_pending_onload_raw_monitors();
3854
3855 // Create the VMThread
3856 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3857
3858 VMThread::create();
3859 Thread* vmthread = VMThread::vm_thread();
3860
3861 if (!os::create_thread(vmthread, os::vm_thread)) {
3862 vm_exit_during_initialization("Cannot create VM thread. "
3863 "Out of system resources.");
3864 }
3865
3866 // Wait for the VM thread to become ready, and VMThread::run to initialize
3867 // Monitors can have spurious returns, must always check another state flag
3868 {
3869 MutexLocker ml(Notify_lock);
3870 os::start_thread(vmthread);
3871 while (vmthread->active_handles() == NULL) {
3872 Notify_lock->wait();
3873 }
3874 }
3875 }
3876
3877 assert(Universe::is_fully_initialized(), "not initialized");
3878 if (VerifyDuringStartup) {
3879 // Make sure we're starting with a clean slate.
3880 VM_Verify verify_op;
3881 VMThread::execute(&verify_op);
3882 }
3883
3884 Thread* THREAD = Thread::current();
3885
3886 // Always call even when there are not JVMTI environments yet, since environments
3887 // may be attached late and JVMTI must track phases of VM execution
3888 JvmtiExport::enter_early_start_phase();
3889
3890 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3891 JvmtiExport::post_early_vm_start();
3892
3893 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3894
3895 // We need this for ClassDataSharing - the initial vm.info property is set
3896 // with the default value of CDS "sharing" which may be reset through
3897 // command line options.
3898 reset_vm_info_property(CHECK_JNI_ERR);
3899
3900 quicken_jni_functions();
3901
3902 // No more stub generation allowed after that point.
3903 StubCodeDesc::freeze();
3904
3905 // Set flag that basic initialization has completed. Used by exceptions and various
3906 // debug stuff, that does not work until all basic classes have been initialized.
3907 set_init_completed();
3908
3909 LogConfiguration::post_initialize();
3910 Metaspace::post_initialize();
3911
3912 HOTSPOT_VM_INIT_END();
3913
3914 // record VM initialization completion time
3915 #if INCLUDE_MANAGEMENT
3916 Management::record_vm_init_completed();
3917 #endif // INCLUDE_MANAGEMENT
3918
3919 // Signal Dispatcher needs to be started before VMInit event is posted
3920 os::signal_init(CHECK_JNI_ERR);
3921
3922 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3923 if (!DisableAttachMechanism) {
3924 AttachListener::vm_start();
3925 if (StartAttachListener || AttachListener::init_at_startup()) {
3926 AttachListener::init();
3927 }
3928 }
3929
3930 // Launch -Xrun agents
3931 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3932 // back-end can launch with -Xdebug -Xrunjdwp.
3933 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3934 create_vm_init_libraries();
3935 }
3936
3937 if (CleanChunkPoolAsync) {
3938 Chunk::start_chunk_pool_cleaner_task();
3939 }
3940
3941 // initialize compiler(s)
3942 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3943 CompileBroker::compilation_init(CHECK_JNI_ERR);
3944 #endif
3945
3946 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3947 // It is done after compilers are initialized, because otherwise compilations of
3948 // signature polymorphic MH intrinsics can be missed
3949 // (see SystemDictionary::find_method_handle_intrinsic).
3950 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3951
3952 // This will initialize the module system. Only java.base classes can be
3953 // loaded until phase 2 completes
3954 call_initPhase2(CHECK_JNI_ERR);
3955
3956 // Always call even when there are not JVMTI environments yet, since environments
3957 // may be attached late and JVMTI must track phases of VM execution
3958 JvmtiExport::enter_start_phase();
3959
3960 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3961 JvmtiExport::post_vm_start();
3962
3963 // Final system initialization including security manager and system class loader
3964 call_initPhase3(CHECK_JNI_ERR);
3965
3966 // cache the system and platform class loaders
3967 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
3968
3969 #if INCLUDE_JVMCI
3970 if (EnableJVMCI) {
3971 // Initialize JVMCI eagerly if JVMCIPrintProperties is enabled.
3972 // The JVMCI Java initialization code will read this flag and
3973 // do the printing if it's set.
3974 bool init = JVMCIPrintProperties;
3975
3976 if (!init) {
3977 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
3978 // compilations via JVMCI will not actually block until JVMCI is initialized.
3979 init = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
3980 }
3981
3982 if (init) {
3983 JVMCIRuntime::force_initialization(CHECK_JNI_ERR);
3984 }
3985 }
3986 #endif
3987
3988 // Always call even when there are not JVMTI environments yet, since environments
3989 // may be attached late and JVMTI must track phases of VM execution
3990 JvmtiExport::enter_live_phase();
3991
3992 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3993 JvmtiExport::post_vm_initialized();
3994
3995 if (TRACE_START() != JNI_OK) {
3996 vm_exit_during_initialization("Failed to start tracing backend.");
3997 }
3998
3999 #if INCLUDE_MANAGEMENT
4000 Management::initialize(THREAD);
4001
4002 if (HAS_PENDING_EXCEPTION) {
4003 // management agent fails to start possibly due to
4004 // configuration problem and is responsible for printing
4005 // stack trace if appropriate. Simply exit VM.
4006 vm_exit(1);
4007 }
4008 #endif // INCLUDE_MANAGEMENT
4009
4010 if (MemProfiling) MemProfiler::engage();
4011 StatSampler::engage();
4012 if (CheckJNICalls) JniPeriodicChecker::engage();
4013
4014 BiasedLocking::init();
4015
4016 #if INCLUDE_RTM_OPT
4017 RTMLockingCounters::init();
4018 #endif
4019
4020 if (JDK_Version::current().post_vm_init_hook_enabled()) {
4021 call_postVMInitHook(THREAD);
4022 // The Java side of PostVMInitHook.run must deal with all
4023 // exceptions and provide means of diagnosis.
4024 if (HAS_PENDING_EXCEPTION) {
4025 CLEAR_PENDING_EXCEPTION;
4026 }
4027 }
4028
4029 {
4030 MutexLocker ml(PeriodicTask_lock);
4031 // Make sure the WatcherThread can be started by WatcherThread::start()
4032 // or by dynamic enrollment.
4033 WatcherThread::make_startable();
4034 // Start up the WatcherThread if there are any periodic tasks
4035 // NOTE: All PeriodicTasks should be registered by now. If they
4036 // aren't, late joiners might appear to start slowly (we might
4037 // take a while to process their first tick).
4038 if (PeriodicTask::num_tasks() > 0) {
4039 WatcherThread::start();
4040 }
4041 }
4042
4043 create_vm_timer.end();
4044 #ifdef ASSERT
4045 _vm_complete = true;
4046 #endif
4047
4048 if (DumpSharedSpaces) {
4049 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
4050 ShouldNotReachHere();
4051 }
4052
4053 return JNI_OK;
4054 }
4055
4056 // type for the Agent_OnLoad and JVM_OnLoad entry points
4057 extern "C" {
4058 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
4059 }
4060 // Find a command line agent library and return its entry point for
4061 // -agentlib: -agentpath: -Xrun
4062 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
4063 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
4064 const char *on_load_symbols[],
4065 size_t num_symbol_entries) {
4066 OnLoadEntry_t on_load_entry = NULL;
4067 void *library = NULL;
4068
4069 if (!agent->valid()) {
4070 char buffer[JVM_MAXPATHLEN];
4071 char ebuf[1024] = "";
4072 const char *name = agent->name();
4073 const char *msg = "Could not find agent library ";
4074
4075 // First check to see if agent is statically linked into executable
4076 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
4077 library = agent->os_lib();
4078 } else if (agent->is_absolute_path()) {
4079 library = os::dll_load(name, ebuf, sizeof ebuf);
4080 if (library == NULL) {
4081 const char *sub_msg = " in absolute path, with error: ";
4082 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4083 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4084 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4085 // If we can't find the agent, exit.
4086 vm_exit_during_initialization(buf, NULL);
4087 FREE_C_HEAP_ARRAY(char, buf);
4088 }
4089 } else {
4090 // Try to load the agent from the standard dll directory
4091 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
4092 name)) {
4093 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4094 }
4095 if (library == NULL) { // Try the library path directory.
4096 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
4097 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4098 }
4099 if (library == NULL) {
4100 const char *sub_msg = " on the library path, with error: ";
4101 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4102 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4103 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4104 // If we can't find the agent, exit.
4105 vm_exit_during_initialization(buf, NULL);
4106 FREE_C_HEAP_ARRAY(char, buf);
4107 }
4108 }
4109 }
4110 agent->set_os_lib(library);
4111 agent->set_valid();
4112 }
4113
4114 // Find the OnLoad function.
4115 on_load_entry =
4116 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4117 false,
4118 on_load_symbols,
4119 num_symbol_entries));
4120 return on_load_entry;
4121 }
4122
4123 // Find the JVM_OnLoad entry point
4124 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4125 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4126 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4127 }
4128
4129 // Find the Agent_OnLoad entry point
4130 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4131 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4132 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4133 }
4134
4135 // For backwards compatibility with -Xrun
4136 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4137 // treated like -agentpath:
4138 // Must be called before agent libraries are created
4139 void Threads::convert_vm_init_libraries_to_agents() {
4140 AgentLibrary* agent;
4141 AgentLibrary* next;
4142
4143 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4144 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4145 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4146
4147 // If there is an JVM_OnLoad function it will get called later,
4148 // otherwise see if there is an Agent_OnLoad
4149 if (on_load_entry == NULL) {
4150 on_load_entry = lookup_agent_on_load(agent);
4151 if (on_load_entry != NULL) {
4152 // switch it to the agent list -- so that Agent_OnLoad will be called,
4153 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4154 Arguments::convert_library_to_agent(agent);
4155 } else {
4156 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4157 }
4158 }
4159 }
4160 }
4161
4162 // Create agents for -agentlib: -agentpath: and converted -Xrun
4163 // Invokes Agent_OnLoad
4164 // Called very early -- before JavaThreads exist
4165 void Threads::create_vm_init_agents() {
4166 extern struct JavaVM_ main_vm;
4167 AgentLibrary* agent;
4168
4169 JvmtiExport::enter_onload_phase();
4170
4171 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4172 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4173
4174 if (on_load_entry != NULL) {
4175 // Invoke the Agent_OnLoad function
4176 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4177 if (err != JNI_OK) {
4178 vm_exit_during_initialization("agent library failed to init", agent->name());
4179 }
4180 } else {
4181 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4182 }
4183 }
4184 JvmtiExport::enter_primordial_phase();
4185 }
4186
4187 extern "C" {
4188 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4189 }
4190
4191 void Threads::shutdown_vm_agents() {
4192 // Send any Agent_OnUnload notifications
4193 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4194 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4195 extern struct JavaVM_ main_vm;
4196 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4197
4198 // Find the Agent_OnUnload function.
4199 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4200 os::find_agent_function(agent,
4201 false,
4202 on_unload_symbols,
4203 num_symbol_entries));
4204
4205 // Invoke the Agent_OnUnload function
4206 if (unload_entry != NULL) {
4207 JavaThread* thread = JavaThread::current();
4208 ThreadToNativeFromVM ttn(thread);
4209 HandleMark hm(thread);
4210 (*unload_entry)(&main_vm);
4211 }
4212 }
4213 }
4214
4215 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4216 // Invokes JVM_OnLoad
4217 void Threads::create_vm_init_libraries() {
4218 extern struct JavaVM_ main_vm;
4219 AgentLibrary* agent;
4220
4221 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4222 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4223
4224 if (on_load_entry != NULL) {
4225 // Invoke the JVM_OnLoad function
4226 JavaThread* thread = JavaThread::current();
4227 ThreadToNativeFromVM ttn(thread);
4228 HandleMark hm(thread);
4229 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4230 if (err != JNI_OK) {
4231 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4232 }
4233 } else {
4234 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4235 }
4236 }
4237 }
4238
4239
4240 // Last thread running calls java.lang.Shutdown.shutdown()
4241 void JavaThread::invoke_shutdown_hooks() {
4242 HandleMark hm(this);
4243
4244 // We could get here with a pending exception, if so clear it now.
4245 if (this->has_pending_exception()) {
4246 this->clear_pending_exception();
4247 }
4248
4249 EXCEPTION_MARK;
4250 Klass* shutdown_klass =
4251 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4252 THREAD);
4253 if (shutdown_klass != NULL) {
4254 // SystemDictionary::resolve_or_null will return null if there was
4255 // an exception. If we cannot load the Shutdown class, just don't
4256 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4257 // and finalizers (if runFinalizersOnExit is set) won't be run.
4258 // Note that if a shutdown hook was registered or runFinalizersOnExit
4259 // was called, the Shutdown class would have already been loaded
4260 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
4261 JavaValue result(T_VOID);
4262 JavaCalls::call_static(&result,
4263 shutdown_klass,
4264 vmSymbols::shutdown_method_name(),
4265 vmSymbols::void_method_signature(),
4266 THREAD);
4267 }
4268 CLEAR_PENDING_EXCEPTION;
4269 }
4270
4271 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4272 // the program falls off the end of main(). Another VM exit path is through
4273 // vm_exit() when the program calls System.exit() to return a value or when
4274 // there is a serious error in VM. The two shutdown paths are not exactly
4275 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4276 // and VM_Exit op at VM level.
4277 //
4278 // Shutdown sequence:
4279 // + Shutdown native memory tracking if it is on
4280 // + Wait until we are the last non-daemon thread to execute
4281 // <-- every thing is still working at this moment -->
4282 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4283 // shutdown hooks, run finalizers if finalization-on-exit
4284 // + Call before_exit(), prepare for VM exit
4285 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4286 // currently the only user of this mechanism is File.deleteOnExit())
4287 // > stop StatSampler, watcher thread, CMS threads,
4288 // post thread end and vm death events to JVMTI,
4289 // stop signal thread
4290 // + Call JavaThread::exit(), it will:
4291 // > release JNI handle blocks, remove stack guard pages
4292 // > remove this thread from Threads list
4293 // <-- no more Java code from this thread after this point -->
4294 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4295 // the compiler threads at safepoint
4296 // <-- do not use anything that could get blocked by Safepoint -->
4297 // + Disable tracing at JNI/JVM barriers
4298 // + Set _vm_exited flag for threads that are still running native code
4299 // + Delete this thread
4300 // + Call exit_globals()
4301 // > deletes tty
4302 // > deletes PerfMemory resources
4303 // + Return to caller
4304
4305 bool Threads::destroy_vm() {
4306 JavaThread* thread = JavaThread::current();
4307
4308 #ifdef ASSERT
4309 _vm_complete = false;
4310 #endif
4311 // Wait until we are the last non-daemon thread to execute
4312 { MutexLocker nu(Threads_lock);
4313 while (Threads::number_of_non_daemon_threads() > 1)
4314 // This wait should make safepoint checks, wait without a timeout,
4315 // and wait as a suspend-equivalent condition.
4316 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4317 Mutex::_as_suspend_equivalent_flag);
4318 }
4319
4320 // Hang forever on exit if we are reporting an error.
4321 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4322 os::infinite_sleep();
4323 }
4324 os::wait_for_keypress_at_exit();
4325
4326 // run Java level shutdown hooks
4327 thread->invoke_shutdown_hooks();
4328
4329 before_exit(thread);
4330
4331 thread->exit(true);
4332
4333 // Stop VM thread.
4334 {
4335 // 4945125 The vm thread comes to a safepoint during exit.
4336 // GC vm_operations can get caught at the safepoint, and the
4337 // heap is unparseable if they are caught. Grab the Heap_lock
4338 // to prevent this. The GC vm_operations will not be able to
4339 // queue until after the vm thread is dead. After this point,
4340 // we'll never emerge out of the safepoint before the VM exits.
4341
4342 MutexLocker ml(Heap_lock);
4343
4344 VMThread::wait_for_vm_thread_exit();
4345 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4346 VMThread::destroy();
4347 }
4348
4349 // clean up ideal graph printers
4350 #if defined(COMPILER2) && !defined(PRODUCT)
4351 IdealGraphPrinter::clean_up();
4352 #endif
4353
4354 // Now, all Java threads are gone except daemon threads. Daemon threads
4355 // running Java code or in VM are stopped by the Safepoint. However,
4356 // daemon threads executing native code are still running. But they
4357 // will be stopped at native=>Java/VM barriers. Note that we can't
4358 // simply kill or suspend them, as it is inherently deadlock-prone.
4359
4360 VM_Exit::set_vm_exited();
4361
4362 notify_vm_shutdown();
4363
4364 // We are after VM_Exit::set_vm_exited() so we can't call
4365 // thread->smr_delete() or we will block on the Threads_lock.
4366 // Deleting the shutdown thread here is safe because another
4367 // JavaThread cannot have an active ThreadsListHandle for
4368 // this JavaThread.
4369 delete thread;
4370
4371 #if INCLUDE_JVMCI
4372 if (JVMCICounterSize > 0) {
4373 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4374 }
4375 #endif
4376
4377 // exit_globals() will delete tty
4378 exit_globals();
4379
4380 LogConfiguration::finalize();
4381
4382 return true;
4383 }
4384
4385
4386 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4387 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4388 return is_supported_jni_version(version);
4389 }
4390
4391
4392 jboolean Threads::is_supported_jni_version(jint version) {
4393 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4394 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4395 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4396 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4397 if (version == JNI_VERSION_9) return JNI_TRUE;
4398 if (version == JNI_VERSION_10) return JNI_TRUE;
4399 return JNI_FALSE;
4400 }
4401
4402
4403 void Threads::add(JavaThread* p, bool force_daemon) {
4404 // The threads lock must be owned at this point
4405 assert_locked_or_safepoint(Threads_lock);
4406
4407 // See the comment for this method in thread.hpp for its purpose and
4408 // why it is called here.
4409 p->initialize_queues();
4410 p->set_next(_thread_list);
4411 _thread_list = p;
4412
4413 // Once a JavaThread is added to the Threads list, smr_delete() has
4414 // to be used to delete it. Otherwise we can just delete it directly.
4415 p->set_on_thread_list();
4416
4417 _number_of_threads++;
4418 oop threadObj = p->threadObj();
4419 bool daemon = true;
4420 // Bootstrapping problem: threadObj can be null for initial
4421 // JavaThread (or for threads attached via JNI)
4422 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4423 _number_of_non_daemon_threads++;
4424 daemon = false;
4425 }
4426
4427 ThreadService::add_thread(p, daemon);
4428
4429 // Maintain fast thread list
4430 ThreadsSMRSupport::add_thread(p);
4431
4432 // Possible GC point.
4433 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4434 }
4435
4436 void Threads::remove(JavaThread* p) {
4437
4438 // Reclaim the objectmonitors from the omInUseList and omFreeList of the moribund thread.
4439 ObjectSynchronizer::omFlush(p);
4440
4441 // Extra scope needed for Thread_lock, so we can check
4442 // that we do not remove thread without safepoint code notice
4443 { MutexLocker ml(Threads_lock);
4444
4445 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4446
4447 // Maintain fast thread list
4448 ThreadsSMRSupport::remove_thread(p);
4449
4450 JavaThread* current = _thread_list;
4451 JavaThread* prev = NULL;
4452
4453 while (current != p) {
4454 prev = current;
4455 current = current->next();
4456 }
4457
4458 if (prev) {
4459 prev->set_next(current->next());
4460 } else {
4461 _thread_list = p->next();
4462 }
4463
4464 _number_of_threads--;
4465 oop threadObj = p->threadObj();
4466 bool daemon = true;
4467 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4468 _number_of_non_daemon_threads--;
4469 daemon = false;
4470
4471 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4472 // on destroy_vm will wake up.
4473 if (number_of_non_daemon_threads() == 1) {
4474 Threads_lock->notify_all();
4475 }
4476 }
4477 ThreadService::remove_thread(p, daemon);
4478
4479 // Make sure that safepoint code disregard this thread. This is needed since
4480 // the thread might mess around with locks after this point. This can cause it
4481 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4482 // of this thread since it is removed from the queue.
4483 p->set_terminated_value();
4484 } // unlock Threads_lock
4485
4486 // Since Events::log uses a lock, we grab it outside the Threads_lock
4487 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4488 }
4489
4490 // Operations on the Threads list for GC. These are not explicitly locked,
4491 // but the garbage collector must provide a safe context for them to run.
4492 // In particular, these things should never be called when the Threads_lock
4493 // is held by some other thread. (Note: the Safepoint abstraction also
4494 // uses the Threads_lock to guarantee this property. It also makes sure that
4495 // all threads gets blocked when exiting or starting).
4496
4497 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4498 ALL_JAVA_THREADS(p) {
4499 p->oops_do(f, cf);
4500 }
4501 VMThread::vm_thread()->oops_do(f, cf);
4502 }
4503
4504 void Threads::change_thread_claim_parity() {
4505 // Set the new claim parity.
4506 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4507 "Not in range.");
4508 _thread_claim_parity++;
4509 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4510 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4511 "Not in range.");
4512 }
4513
4514 #ifdef ASSERT
4515 void Threads::assert_all_threads_claimed() {
4516 ALL_JAVA_THREADS(p) {
4517 const int thread_parity = p->oops_do_parity();
4518 assert((thread_parity == _thread_claim_parity),
4519 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4520 }
4521 VMThread* vmt = VMThread::vm_thread();
4522 const int thread_parity = vmt->oops_do_parity();
4523 assert((thread_parity == _thread_claim_parity),
4524 "VMThread " PTR_FORMAT " has incorrect parity %d != %d", p2i(vmt), thread_parity, _thread_claim_parity);
4525 }
4526 #endif // ASSERT
4527
4528 class ParallelOopsDoThreadClosure : public ThreadClosure {
4529 private:
4530 OopClosure* _f;
4531 CodeBlobClosure* _cf;
4532 CodeBlobClosure* _nmethods_cl;
4533 ThreadClosure* _thread_cl;
4534 public:
4535 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf, CodeBlobClosure* nmethods_cl, ThreadClosure* thread_cl) :
4536 _f(f), _cf(cf), _nmethods_cl(nmethods_cl), _thread_cl(thread_cl) {}
4537 void do_thread(Thread* t) {
4538 t->oops_do(_f, _cf);
4539 if (_thread_cl != NULL) {
4540 _thread_cl->do_thread(t);
4541 }
4542 if (_nmethods_cl != NULL && t->is_Java_thread() && !t->is_Code_cache_sweeper_thread()) {
4543 ((JavaThread*)t)->nmethods_do(_nmethods_cl);
4544 }
4545 }
4546 };
4547
4548 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf, CodeBlobClosure* nmethods_cl,
4549 ThreadClosure* thread_cl) {
4550 ParallelOopsDoThreadClosure tc(f, cf, nmethods_cl, thread_cl);
4551 possibly_parallel_threads_do(is_par, &tc);
4552 }
4553
4554 #if INCLUDE_ALL_GCS
4555 // Used by ParallelScavenge
4556 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4557 ALL_JAVA_THREADS(p) {
4558 q->enqueue(new ThreadRootsTask(p));
4559 }
4560 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4561 }
4562
4563 // Used by Parallel Old
4564 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4565 ALL_JAVA_THREADS(p) {
4566 q->enqueue(new ThreadRootsMarkingTask(p));
4567 }
4568 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4569 }
4570
4571 void JavaThread::set_gc_state(char in_prog) {
4572 _gc_state = in_prog;
4573 }
4574
4575 void JavaThread::set_gc_state_all_threads(char in_prog) {
4576 assert_locked_or_safepoint(Threads_lock);
4577 _gc_state_global = in_prog;
4578 ALL_JAVA_THREADS(t) {
4579 t->set_gc_state(in_prog);
4580 }
4581 }
4582
4583 #endif // INCLUDE_ALL_GCS
4584
4585 void Threads::nmethods_do(CodeBlobClosure* cf) {
4586 ALL_JAVA_THREADS(p) {
4587 // This is used by the code cache sweeper to mark nmethods that are active
4588 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4589 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4590 if(!p->is_Code_cache_sweeper_thread()) {
4591 p->nmethods_do(cf);
4592 }
4593 }
4594 }
4595
4596 void Threads::metadata_do(void f(Metadata*)) {
4597 ALL_JAVA_THREADS(p) {
4598 p->metadata_do(f);
4599 }
4600 }
4601
4602 class ThreadHandlesClosure : public ThreadClosure {
4603 void (*_f)(Metadata*);
4604 public:
4605 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4606 virtual void do_thread(Thread* thread) {
4607 thread->metadata_handles_do(_f);
4608 }
4609 };
4610
4611 void Threads::metadata_handles_do(void f(Metadata*)) {
4612 // Only walk the Handles in Thread.
4613 ThreadHandlesClosure handles_closure(f);
4614 threads_do(&handles_closure);
4615 }
4616
4617 void Threads::deoptimized_wrt_marked_nmethods() {
4618 ALL_JAVA_THREADS(p) {
4619 p->deoptimized_wrt_marked_nmethods();
4620 }
4621 }
4622
4623
4624 // Get count Java threads that are waiting to enter the specified monitor.
4625 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4626 int count,
4627 address monitor) {
4628 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4629
4630 int i = 0;
4631 DO_JAVA_THREADS(t_list, p) {
4632 if (!p->can_call_java()) continue;
4633
4634 address pending = (address)p->current_pending_monitor();
4635 if (pending == monitor) { // found a match
4636 if (i < count) result->append(p); // save the first count matches
4637 i++;
4638 }
4639 }
4640
4641 return result;
4642 }
4643
4644
4645 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4646 address owner) {
4647 // NULL owner means not locked so we can skip the search
4648 if (owner == NULL) return NULL;
4649
4650 DO_JAVA_THREADS(t_list, p) {
4651 // first, see if owner is the address of a Java thread
4652 if (owner == (address)p) return p;
4653 }
4654
4655 // Cannot assert on lack of success here since this function may be
4656 // used by code that is trying to report useful problem information
4657 // like deadlock detection.
4658 if (UseHeavyMonitors) return NULL;
4659
4660 // If we didn't find a matching Java thread and we didn't force use of
4661 // heavyweight monitors, then the owner is the stack address of the
4662 // Lock Word in the owning Java thread's stack.
4663 //
4664 JavaThread* the_owner = NULL;
4665 DO_JAVA_THREADS(t_list, q) {
4666 if (q->is_lock_owned(owner)) {
4667 the_owner = q;
4668 break;
4669 }
4670 }
4671
4672 // cannot assert on lack of success here; see above comment
4673 return the_owner;
4674 }
4675
4676 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4677 void Threads::print_on(outputStream* st, bool print_stacks,
4678 bool internal_format, bool print_concurrent_locks) {
4679 char buf[32];
4680 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4681
4682 st->print_cr("Full thread dump %s (%s %s):",
4683 Abstract_VM_Version::vm_name(),
4684 Abstract_VM_Version::vm_release(),
4685 Abstract_VM_Version::vm_info_string());
4686 st->cr();
4687
4688 #if INCLUDE_SERVICES
4689 // Dump concurrent locks
4690 ConcurrentLocksDump concurrent_locks;
4691 if (print_concurrent_locks) {
4692 concurrent_locks.dump_at_safepoint();
4693 }
4694 #endif // INCLUDE_SERVICES
4695
4696 ThreadsSMRSupport::print_info_on(st);
4697 st->cr();
4698
4699 ALL_JAVA_THREADS(p) {
4700 ResourceMark rm;
4701 p->print_on(st);
4702 if (print_stacks) {
4703 if (internal_format) {
4704 p->trace_stack();
4705 } else {
4706 p->print_stack_on(st);
4707 }
4708 }
4709 st->cr();
4710 #if INCLUDE_SERVICES
4711 if (print_concurrent_locks) {
4712 concurrent_locks.print_locks_on(p, st);
4713 }
4714 #endif // INCLUDE_SERVICES
4715 }
4716
4717 VMThread::vm_thread()->print_on(st);
4718 st->cr();
4719 Universe::heap()->print_gc_threads_on(st);
4720 WatcherThread* wt = WatcherThread::watcher_thread();
4721 if (wt != NULL) {
4722 wt->print_on(st);
4723 st->cr();
4724 }
4725
4726 st->flush();
4727 }
4728
4729 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4730 int buflen, bool* found_current) {
4731 if (this_thread != NULL) {
4732 bool is_current = (current == this_thread);
4733 *found_current = *found_current || is_current;
4734 st->print("%s", is_current ? "=>" : " ");
4735
4736 st->print(PTR_FORMAT, p2i(this_thread));
4737 st->print(" ");
4738 this_thread->print_on_error(st, buf, buflen);
4739 st->cr();
4740 }
4741 }
4742
4743 class PrintOnErrorClosure : public ThreadClosure {
4744 outputStream* _st;
4745 Thread* _current;
4746 char* _buf;
4747 int _buflen;
4748 bool* _found_current;
4749 public:
4750 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4751 int buflen, bool* found_current) :
4752 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4753
4754 virtual void do_thread(Thread* thread) {
4755 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4756 }
4757 };
4758
4759 // Threads::print_on_error() is called by fatal error handler. It's possible
4760 // that VM is not at safepoint and/or current thread is inside signal handler.
4761 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4762 // memory (even in resource area), it might deadlock the error handler.
4763 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4764 int buflen) {
4765 ThreadsSMRSupport::print_info_on(st);
4766 st->cr();
4767
4768 bool found_current = false;
4769 st->print_cr("Java Threads: ( => current thread )");
4770 ALL_JAVA_THREADS(thread) {
4771 print_on_error(thread, st, current, buf, buflen, &found_current);
4772 }
4773 st->cr();
4774
4775 st->print_cr("Other Threads:");
4776 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4777 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4778
4779 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4780 Universe::heap()->gc_threads_do(&print_closure);
4781
4782 if (!found_current) {
4783 st->cr();
4784 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4785 current->print_on_error(st, buf, buflen);
4786 st->cr();
4787 }
4788 st->cr();
4789
4790 st->print_cr("Threads with active compile tasks:");
4791 print_threads_compiling(st, buf, buflen);
4792 }
4793
4794 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) {
4795 ALL_JAVA_THREADS(thread) {
4796 if (thread->is_Compiler_thread()) {
4797 CompilerThread* ct = (CompilerThread*) thread;
4798
4799 // Keep task in local variable for NULL check.
4800 // ct->_task might be set to NULL by concurring compiler thread
4801 // because it completed the compilation. The task is never freed,
4802 // though, just returned to a free list.
4803 CompileTask* task = ct->task();
4804 if (task != NULL) {
4805 thread->print_name_on_error(st, buf, buflen);
4806 task->print(st, NULL, true, true);
4807 }
4808 }
4809 }
4810 }
4811
4812
4813 // Internal SpinLock and Mutex
4814 // Based on ParkEvent
4815
4816 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4817 //
4818 // We employ SpinLocks _only for low-contention, fixed-length
4819 // short-duration critical sections where we're concerned
4820 // about native mutex_t or HotSpot Mutex:: latency.
4821 // The mux construct provides a spin-then-block mutual exclusion
4822 // mechanism.
4823 //
4824 // Testing has shown that contention on the ListLock guarding gFreeList
4825 // is common. If we implement ListLock as a simple SpinLock it's common
4826 // for the JVM to devolve to yielding with little progress. This is true
4827 // despite the fact that the critical sections protected by ListLock are
4828 // extremely short.
4829 //
4830 // TODO-FIXME: ListLock should be of type SpinLock.
4831 // We should make this a 1st-class type, integrated into the lock
4832 // hierarchy as leaf-locks. Critically, the SpinLock structure
4833 // should have sufficient padding to avoid false-sharing and excessive
4834 // cache-coherency traffic.
4835
4836
4837 typedef volatile int SpinLockT;
4838
4839 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4840 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4841 return; // normal fast-path return
4842 }
4843
4844 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4845 TEVENT(SpinAcquire - ctx);
4846 int ctr = 0;
4847 int Yields = 0;
4848 for (;;) {
4849 while (*adr != 0) {
4850 ++ctr;
4851 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4852 if (Yields > 5) {
4853 os::naked_short_sleep(1);
4854 } else {
4855 os::naked_yield();
4856 ++Yields;
4857 }
4858 } else {
4859 SpinPause();
4860 }
4861 }
4862 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4863 }
4864 }
4865
4866 void Thread::SpinRelease(volatile int * adr) {
4867 assert(*adr != 0, "invariant");
4868 OrderAccess::fence(); // guarantee at least release consistency.
4869 // Roach-motel semantics.
4870 // It's safe if subsequent LDs and STs float "up" into the critical section,
4871 // but prior LDs and STs within the critical section can't be allowed
4872 // to reorder or float past the ST that releases the lock.
4873 // Loads and stores in the critical section - which appear in program
4874 // order before the store that releases the lock - must also appear
4875 // before the store that releases the lock in memory visibility order.
4876 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4877 // the ST of 0 into the lock-word which releases the lock, so fence
4878 // more than covers this on all platforms.
4879 *adr = 0;
4880 }
4881
4882 // muxAcquire and muxRelease:
4883 //
4884 // * muxAcquire and muxRelease support a single-word lock-word construct.
4885 // The LSB of the word is set IFF the lock is held.
4886 // The remainder of the word points to the head of a singly-linked list
4887 // of threads blocked on the lock.
4888 //
4889 // * The current implementation of muxAcquire-muxRelease uses its own
4890 // dedicated Thread._MuxEvent instance. If we're interested in
4891 // minimizing the peak number of extant ParkEvent instances then
4892 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4893 // as certain invariants were satisfied. Specifically, care would need
4894 // to be taken with regards to consuming unpark() "permits".
4895 // A safe rule of thumb is that a thread would never call muxAcquire()
4896 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4897 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4898 // consume an unpark() permit intended for monitorenter, for instance.
4899 // One way around this would be to widen the restricted-range semaphore
4900 // implemented in park(). Another alternative would be to provide
4901 // multiple instances of the PlatformEvent() for each thread. One
4902 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4903 //
4904 // * Usage:
4905 // -- Only as leaf locks
4906 // -- for short-term locking only as muxAcquire does not perform
4907 // thread state transitions.
4908 //
4909 // Alternatives:
4910 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4911 // but with parking or spin-then-park instead of pure spinning.
4912 // * Use Taura-Oyama-Yonenzawa locks.
4913 // * It's possible to construct a 1-0 lock if we encode the lockword as
4914 // (List,LockByte). Acquire will CAS the full lockword while Release
4915 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4916 // acquiring threads use timers (ParkTimed) to detect and recover from
4917 // the stranding window. Thread/Node structures must be aligned on 256-byte
4918 // boundaries by using placement-new.
4919 // * Augment MCS with advisory back-link fields maintained with CAS().
4920 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4921 // The validity of the backlinks must be ratified before we trust the value.
4922 // If the backlinks are invalid the exiting thread must back-track through the
4923 // the forward links, which are always trustworthy.
4924 // * Add a successor indication. The LockWord is currently encoded as
4925 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4926 // to provide the usual futile-wakeup optimization.
4927 // See RTStt for details.
4928 // * Consider schedctl.sc_nopreempt to cover the critical section.
4929 //
4930
4931
4932 const intptr_t LOCKBIT = 1;
4933
4934 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4935 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4936 if (w == 0) return;
4937 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4938 return;
4939 }
4940
4941 TEVENT(muxAcquire - Contention);
4942 ParkEvent * const Self = Thread::current()->_MuxEvent;
4943 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4944 for (;;) {
4945 int its = (os::is_MP() ? 100 : 0) + 1;
4946
4947 // Optional spin phase: spin-then-park strategy
4948 while (--its >= 0) {
4949 w = *Lock;
4950 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4951 return;
4952 }
4953 }
4954
4955 Self->reset();
4956 Self->OnList = intptr_t(Lock);
4957 // The following fence() isn't _strictly necessary as the subsequent
4958 // CAS() both serializes execution and ratifies the fetched *Lock value.
4959 OrderAccess::fence();
4960 for (;;) {
4961 w = *Lock;
4962 if ((w & LOCKBIT) == 0) {
4963 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4964 Self->OnList = 0; // hygiene - allows stronger asserts
4965 return;
4966 }
4967 continue; // Interference -- *Lock changed -- Just retry
4968 }
4969 assert(w & LOCKBIT, "invariant");
4970 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4971 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4972 }
4973
4974 while (Self->OnList != 0) {
4975 Self->park();
4976 }
4977 }
4978 }
4979
4980 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4981 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4982 if (w == 0) return;
4983 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4984 return;
4985 }
4986
4987 TEVENT(muxAcquire - Contention);
4988 ParkEvent * ReleaseAfter = NULL;
4989 if (ev == NULL) {
4990 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4991 }
4992 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4993 for (;;) {
4994 guarantee(ev->OnList == 0, "invariant");
4995 int its = (os::is_MP() ? 100 : 0) + 1;
4996
4997 // Optional spin phase: spin-then-park strategy
4998 while (--its >= 0) {
4999 w = *Lock;
5000 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
5001 if (ReleaseAfter != NULL) {
5002 ParkEvent::Release(ReleaseAfter);
5003 }
5004 return;
5005 }
5006 }
5007
5008 ev->reset();
5009 ev->OnList = intptr_t(Lock);
5010 // The following fence() isn't _strictly necessary as the subsequent
5011 // CAS() both serializes execution and ratifies the fetched *Lock value.
5012 OrderAccess::fence();
5013 for (;;) {
5014 w = *Lock;
5015 if ((w & LOCKBIT) == 0) {
5016 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
5017 ev->OnList = 0;
5018 // We call ::Release while holding the outer lock, thus
5019 // artificially lengthening the critical section.
5020 // Consider deferring the ::Release() until the subsequent unlock(),
5021 // after we've dropped the outer lock.
5022 if (ReleaseAfter != NULL) {
5023 ParkEvent::Release(ReleaseAfter);
5024 }
5025 return;
5026 }
5027 continue; // Interference -- *Lock changed -- Just retry
5028 }
5029 assert(w & LOCKBIT, "invariant");
5030 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
5031 if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
5032 }
5033
5034 while (ev->OnList != 0) {
5035 ev->park();
5036 }
5037 }
5038 }
5039
5040 // Release() must extract a successor from the list and then wake that thread.
5041 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
5042 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
5043 // Release() would :
5044 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
5045 // (B) Extract a successor from the private list "in-hand"
5046 // (C) attempt to CAS() the residual back into *Lock over null.
5047 // If there were any newly arrived threads and the CAS() would fail.
5048 // In that case Release() would detach the RATs, re-merge the list in-hand
5049 // with the RATs and repeat as needed. Alternately, Release() might
5050 // detach and extract a successor, but then pass the residual list to the wakee.
5051 // The wakee would be responsible for reattaching and remerging before it
5052 // competed for the lock.
5053 //
5054 // Both "pop" and DMR are immune from ABA corruption -- there can be
5055 // multiple concurrent pushers, but only one popper or detacher.
5056 // This implementation pops from the head of the list. This is unfair,
5057 // but tends to provide excellent throughput as hot threads remain hot.
5058 // (We wake recently run threads first).
5059 //
5060 // All paths through muxRelease() will execute a CAS.
5061 // Release consistency -- We depend on the CAS in muxRelease() to provide full
5062 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
5063 // executed within the critical section are complete and globally visible before the
5064 // store (CAS) to the lock-word that releases the lock becomes globally visible.
5065 void Thread::muxRelease(volatile intptr_t * Lock) {
5066 for (;;) {
5067 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
5068 assert(w & LOCKBIT, "invariant");
5069 if (w == LOCKBIT) return;
5070 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
5071 assert(List != NULL, "invariant");
5072 assert(List->OnList == intptr_t(Lock), "invariant");
5073 ParkEvent * const nxt = List->ListNext;
5074 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
5075
5076 // The following CAS() releases the lock and pops the head element.
5077 // The CAS() also ratifies the previously fetched lock-word value.
5078 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
5079 continue;
5080 }
5081 List->OnList = 0;
5082 OrderAccess::fence();
5083 List->unpark();
5084 return;
5085 }
5086 }
5087
5088
5089 void Threads::verify() {
5090 ALL_JAVA_THREADS(p) {
5091 p->verify();
5092 }
5093 VMThread* thread = VMThread::vm_thread();
5094 if (thread != NULL) thread->verify();
5095 }