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