1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "classfile/classLoader.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/moduleEntry.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "classfile/vmSymbols.hpp"
32 #include "code/codeCache.hpp"
33 #include "code/scopeDesc.hpp"
34 #include "compiler/compileBroker.hpp"
35 #include "compiler/compileTask.hpp"
36 #include "gc/shared/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/allocation.inline.hpp"
47 #include "memory/metaspaceShared.hpp"
48 #include "memory/oopFactory.hpp"
49 #include "memory/resourceArea.hpp"
50 #include "memory/universe.hpp"
51 #include "oops/access.inline.hpp"
52 #include "oops/instanceKlass.hpp"
53 #include "oops/objArrayOop.hpp"
54 #include "oops/oop.inline.hpp"
55 #include "oops/symbol.hpp"
56 #include "oops/typeArrayOop.inline.hpp"
57 #include "oops/verifyOopClosure.hpp"
58 #include "prims/jvm_misc.hpp"
59 #include "prims/jvmtiExport.hpp"
60 #include "prims/jvmtiThreadState.hpp"
61 #include "prims/privilegedStack.hpp"
62 #include "runtime/arguments.hpp"
63 #include "runtime/atomic.hpp"
64 #include "runtime/biasedLocking.hpp"
65 #include "runtime/commandLineFlagConstraintList.hpp"
66 #include "runtime/commandLineFlagWriteableList.hpp"
67 #include "runtime/commandLineFlagRangeList.hpp"
68 #include "runtime/deoptimization.hpp"
69 #include "runtime/frame.inline.hpp"
70 #include "runtime/globals.hpp"
71 #include "runtime/handshake.hpp"
72 #include "runtime/init.hpp"
73 #include "runtime/interfaceSupport.inline.hpp"
74 #include "runtime/java.hpp"
75 #include "runtime/javaCalls.hpp"
76 #include "runtime/jniHandles.inline.hpp"
77 #include "runtime/jniPeriodicChecker.hpp"
78 #include "runtime/memprofiler.hpp"
79 #include "runtime/mutexLocker.hpp"
80 #include "runtime/objectMonitor.hpp"
81 #include "runtime/orderAccess.inline.hpp"
82 #include "runtime/osThread.hpp"
83 #include "runtime/prefetch.inline.hpp"
84 #include "runtime/safepoint.hpp"
85 #include "runtime/safepointMechanism.inline.hpp"
86 #include "runtime/sharedRuntime.hpp"
87 #include "runtime/statSampler.hpp"
88 #include "runtime/stubRoutines.hpp"
89 #include "runtime/sweeper.hpp"
90 #include "runtime/task.hpp"
91 #include "runtime/thread.inline.hpp"
92 #include "runtime/threadCritical.hpp"
93 #include "runtime/threadSMR.inline.hpp"
94 #include "runtime/timer.hpp"
95 #include "runtime/timerTrace.hpp"
96 #include "runtime/vframe.inline.hpp"
97 #include "runtime/vframeArray.hpp"
98 #include "runtime/vframe_hp.hpp"
99 #include "runtime/vmThread.hpp"
100 #include "runtime/vm_operations.hpp"
101 #include "runtime/vm_version.hpp"
102 #include "services/attachListener.hpp"
103 #include "services/management.hpp"
104 #include "services/memTracker.hpp"
105 #include "services/threadService.hpp"
106 #include "trace/traceMacros.hpp"
107 #include "trace/tracing.hpp"
108 #include "trace/tracingExport.hpp"
109 #include "utilities/align.hpp"
110 #include "utilities/defaultStream.hpp"
111 #include "utilities/dtrace.hpp"
112 #include "utilities/events.hpp"
113 #include "utilities/macros.hpp"
114 #include "utilities/preserveException.hpp"
115 #include "utilities/vmError.hpp"
116 #if INCLUDE_ALL_GCS
117 #include "gc/cms/concurrentMarkSweepThread.hpp"
118 #include "gc/g1/concurrentMarkThread.inline.hpp"
119 #include "gc/parallel/pcTasks.hpp"
120 #endif // INCLUDE_ALL_GCS
121 #if INCLUDE_JVMCI
122 #include "jvmci/jvmciCompiler.hpp"
123 #include "jvmci/jvmciRuntime.hpp"
124 #include "logging/logHandle.hpp"
125 #endif
126 #ifdef COMPILER1
127 #include "c1/c1_Compiler.hpp"
128 #endif
129 #ifdef COMPILER2
130 #include "opto/c2compiler.hpp"
131 #include "opto/idealGraphPrinter.hpp"
132 #endif
133 #if INCLUDE_RTM_OPT
134 #include "runtime/rtmLocking.hpp"
135 #endif
136
137 // Initialization after module runtime initialization
138 void universe_post_module_init(); // must happen after call_initPhase2
139
140 #ifdef DTRACE_ENABLED
141
142 // Only bother with this argument setup if dtrace is available
143
144 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
145 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
146
147 #define DTRACE_THREAD_PROBE(probe, javathread) \
148 { \
149 ResourceMark rm(this); \
150 int len = 0; \
151 const char* name = (javathread)->get_thread_name(); \
152 len = strlen(name); \
153 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
154 (char *) name, len, \
155 java_lang_Thread::thread_id((javathread)->threadObj()), \
156 (uintptr_t) (javathread)->osthread()->thread_id(), \
157 java_lang_Thread::is_daemon((javathread)->threadObj())); \
158 }
159
160 #else // ndef DTRACE_ENABLED
161
162 #define DTRACE_THREAD_PROBE(probe, javathread)
163
164 #endif // ndef DTRACE_ENABLED
165
166 #ifndef USE_LIBRARY_BASED_TLS_ONLY
167 // Current thread is maintained as a thread-local variable
168 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
169 #endif
170 // Class hierarchy
171 // - Thread
172 // - VMThread
173 // - WatcherThread
174 // - ConcurrentMarkSweepThread
175 // - JavaThread
176 // - CompilerThread
177
178 // ======= Thread ========
179 // Support for forcing alignment of thread objects for biased locking
180 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
181 if (UseBiasedLocking) {
182 const int alignment = markOopDesc::biased_lock_alignment;
183 size_t aligned_size = size + (alignment - sizeof(intptr_t));
184 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
185 : AllocateHeap(aligned_size, flags, CURRENT_PC,
186 AllocFailStrategy::RETURN_NULL);
187 void* aligned_addr = align_up(real_malloc_addr, alignment);
188 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
189 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
190 "JavaThread alignment code overflowed allocated storage");
191 if (aligned_addr != real_malloc_addr) {
192 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
193 p2i(real_malloc_addr),
194 p2i(aligned_addr));
195 }
196 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
197 return aligned_addr;
198 } else {
199 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
200 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
201 }
202 }
203
204 void Thread::operator delete(void* p) {
205 if (UseBiasedLocking) {
206 FreeHeap(((Thread*) p)->_real_malloc_address);
207 } else {
208 FreeHeap(p);
209 }
210 }
211
212 void JavaThread::smr_delete() {
213 if (_on_thread_list) {
214 ThreadsSMRSupport::smr_delete(this);
215 } else {
216 delete this;
217 }
218 }
219
220 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
221 // JavaThread
222
223
224 Thread::Thread() {
225 // stack and get_thread
226 set_stack_base(NULL);
227 set_stack_size(0);
228 set_self_raw_id(0);
229 set_lgrp_id(-1);
230 DEBUG_ONLY(clear_suspendible_thread();)
231
232 // allocated data structures
233 set_osthread(NULL);
234 set_resource_area(new (mtThread)ResourceArea());
235 DEBUG_ONLY(_current_resource_mark = NULL;)
236 set_handle_area(new (mtThread) HandleArea(NULL));
237 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
238 set_active_handles(NULL);
239 set_free_handle_block(NULL);
240 set_last_handle_mark(NULL);
241
242 // This initial value ==> never claimed.
243 _oops_do_parity = 0;
244 _threads_hazard_ptr = NULL;
245 _nested_threads_hazard_ptr = NULL;
246 _nested_threads_hazard_ptr_cnt = 0;
247
248 // the handle mark links itself to last_handle_mark
249 new HandleMark(this);
250
251 // plain initialization
252 debug_only(_owned_locks = NULL;)
253 debug_only(_allow_allocation_count = 0;)
254 NOT_PRODUCT(_allow_safepoint_count = 0;)
255 NOT_PRODUCT(_skip_gcalot = false;)
256 _jvmti_env_iteration_count = 0;
257 set_allocated_bytes(0);
258 _vm_operation_started_count = 0;
259 _vm_operation_completed_count = 0;
260 _current_pending_monitor = NULL;
261 _current_pending_monitor_is_from_java = true;
262 _current_waiting_monitor = NULL;
263 _num_nested_signal = 0;
264 omFreeList = NULL;
265 omFreeCount = 0;
266 omFreeProvision = 32;
267 omInUseList = NULL;
268 omInUseCount = 0;
269
270 #ifdef ASSERT
271 _visited_for_critical_count = false;
272 #endif
273
274 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
275 Monitor::_safepoint_check_sometimes);
276 _suspend_flags = 0;
277
278 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
279 _hashStateX = os::random();
280 _hashStateY = 842502087;
281 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
282 _hashStateW = 273326509;
283
284 _OnTrap = 0;
285 _schedctl = NULL;
286 _Stalled = 0;
287 _TypeTag = 0x2BAD;
288
289 // Many of the following fields are effectively final - immutable
290 // Note that nascent threads can't use the Native Monitor-Mutex
291 // construct until the _MutexEvent is initialized ...
292 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
293 // we might instead use a stack of ParkEvents that we could provision on-demand.
294 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
295 // and ::Release()
296 _ParkEvent = ParkEvent::Allocate(this);
297 _SleepEvent = ParkEvent::Allocate(this);
298 _MutexEvent = ParkEvent::Allocate(this);
299 _MuxEvent = ParkEvent::Allocate(this);
300
301 #ifdef CHECK_UNHANDLED_OOPS
302 if (CheckUnhandledOops) {
303 _unhandled_oops = new UnhandledOops(this);
304 }
305 #endif // CHECK_UNHANDLED_OOPS
306 #ifdef ASSERT
307 if (UseBiasedLocking) {
308 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
309 assert(this == _real_malloc_address ||
310 this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment),
311 "bug in forced alignment of thread objects");
312 }
313 #endif // ASSERT
314 }
315
316 void Thread::initialize_thread_current() {
317 #ifndef USE_LIBRARY_BASED_TLS_ONLY
318 assert(_thr_current == NULL, "Thread::current already initialized");
319 _thr_current = this;
320 #endif
321 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
322 ThreadLocalStorage::set_thread(this);
323 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
324 }
325
326 void Thread::clear_thread_current() {
327 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
328 #ifndef USE_LIBRARY_BASED_TLS_ONLY
329 _thr_current = NULL;
330 #endif
331 ThreadLocalStorage::set_thread(NULL);
332 }
333
334 void Thread::record_stack_base_and_size() {
335 set_stack_base(os::current_stack_base());
336 set_stack_size(os::current_stack_size());
337 // CR 7190089: on Solaris, primordial thread's stack is adjusted
338 // in initialize_thread(). Without the adjustment, stack size is
339 // incorrect if stack is set to unlimited (ulimit -s unlimited).
340 // So far, only Solaris has real implementation of initialize_thread().
341 //
342 // set up any platform-specific state.
343 os::initialize_thread(this);
344
345 // Set stack limits after thread is initialized.
346 if (is_Java_thread()) {
347 ((JavaThread*) this)->set_stack_overflow_limit();
348 ((JavaThread*) this)->set_reserved_stack_activation(stack_base());
349 }
350 #if INCLUDE_NMT
351 // record thread's native stack, stack grows downward
352 MemTracker::record_thread_stack(stack_end(), stack_size());
353 #endif // INCLUDE_NMT
354 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
355 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
356 os::current_thread_id(), p2i(stack_base() - stack_size()),
357 p2i(stack_base()), stack_size()/1024);
358 }
359
360
361 Thread::~Thread() {
362 EVENT_THREAD_DESTRUCT(this);
363
364 // stack_base can be NULL if the thread is never started or exited before
365 // record_stack_base_and_size called. Although, we would like to ensure
366 // that all started threads do call record_stack_base_and_size(), there is
367 // not proper way to enforce that.
368 #if INCLUDE_NMT
369 if (_stack_base != NULL) {
370 MemTracker::release_thread_stack(stack_end(), stack_size());
371 #ifdef ASSERT
372 set_stack_base(NULL);
373 #endif
374 }
375 #endif // INCLUDE_NMT
376
377 // deallocate data structures
378 delete resource_area();
379 // since the handle marks are using the handle area, we have to deallocated the root
380 // handle mark before deallocating the thread's handle area,
381 assert(last_handle_mark() != NULL, "check we have an element");
382 delete last_handle_mark();
383 assert(last_handle_mark() == NULL, "check we have reached the end");
384
385 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
386 // We NULL out the fields for good hygiene.
387 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
388 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
389 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
390 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
391
392 delete handle_area();
393 delete metadata_handles();
394
395 // SR_handler uses this as a termination indicator -
396 // needs to happen before os::free_thread()
397 delete _SR_lock;
398 _SR_lock = NULL;
399
400 // osthread() can be NULL, if creation of thread failed.
401 if (osthread() != NULL) os::free_thread(osthread());
402
403 // clear Thread::current if thread is deleting itself.
404 // Needed to ensure JNI correctly detects non-attached threads.
405 if (this == Thread::current()) {
406 clear_thread_current();
407 }
408
409 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
410 }
411
412 // NOTE: dummy function for assertion purpose.
413 void Thread::run() {
414 ShouldNotReachHere();
415 }
416
417 #ifdef ASSERT
418 // A JavaThread is considered "dangling" if it is not the current
419 // thread, has been added the Threads list, the system is not at a
420 // safepoint and the Thread is not "protected".
421 //
422 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
423 assert(!thread->is_Java_thread() || Thread::current() == thread ||
424 !((JavaThread *) thread)->on_thread_list() ||
425 SafepointSynchronize::is_at_safepoint() ||
426 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread),
427 "possibility of dangling Thread pointer");
428 }
429 #endif
430
431 ThreadPriority Thread::get_priority(const Thread* const thread) {
432 ThreadPriority priority;
433 // Can return an error!
434 (void)os::get_priority(thread, priority);
435 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
436 return priority;
437 }
438
439 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
440 debug_only(check_for_dangling_thread_pointer(thread);)
441 // Can return an error!
442 (void)os::set_priority(thread, priority);
443 }
444
445
446 void Thread::start(Thread* thread) {
447 // Start is different from resume in that its safety is guaranteed by context or
448 // being called from a Java method synchronized on the Thread object.
449 if (!DisableStartThread) {
450 if (thread->is_Java_thread()) {
451 // Initialize the thread state to RUNNABLE before starting this thread.
452 // Can not set it after the thread started because we do not know the
453 // exact thread state at that time. It could be in MONITOR_WAIT or
454 // in SLEEPING or some other state.
455 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
456 java_lang_Thread::RUNNABLE);
457 }
458 os::start_thread(thread);
459 }
460 }
461
462 // Enqueue a VM_Operation to do the job for us - sometime later
463 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
464 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
465 VMThread::execute(vm_stop);
466 }
467
468
469 // Check if an external suspend request has completed (or has been
470 // cancelled). Returns true if the thread is externally suspended and
471 // false otherwise.
472 //
473 // The bits parameter returns information about the code path through
474 // the routine. Useful for debugging:
475 //
476 // set in is_ext_suspend_completed():
477 // 0x00000001 - routine was entered
478 // 0x00000010 - routine return false at end
479 // 0x00000100 - thread exited (return false)
480 // 0x00000200 - suspend request cancelled (return false)
481 // 0x00000400 - thread suspended (return true)
482 // 0x00001000 - thread is in a suspend equivalent state (return true)
483 // 0x00002000 - thread is native and walkable (return true)
484 // 0x00004000 - thread is native_trans and walkable (needed retry)
485 //
486 // set in wait_for_ext_suspend_completion():
487 // 0x00010000 - routine was entered
488 // 0x00020000 - suspend request cancelled before loop (return false)
489 // 0x00040000 - thread suspended before loop (return true)
490 // 0x00080000 - suspend request cancelled in loop (return false)
491 // 0x00100000 - thread suspended in loop (return true)
492 // 0x00200000 - suspend not completed during retry loop (return false)
493
494 // Helper class for tracing suspend wait debug bits.
495 //
496 // 0x00000100 indicates that the target thread exited before it could
497 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
498 // 0x00080000 each indicate a cancelled suspend request so they don't
499 // count as wait failures either.
500 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
501
502 class TraceSuspendDebugBits : public StackObj {
503 private:
504 JavaThread * jt;
505 bool is_wait;
506 bool called_by_wait; // meaningful when !is_wait
507 uint32_t * bits;
508
509 public:
510 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
511 uint32_t *_bits) {
512 jt = _jt;
513 is_wait = _is_wait;
514 called_by_wait = _called_by_wait;
515 bits = _bits;
516 }
517
518 ~TraceSuspendDebugBits() {
519 if (!is_wait) {
520 #if 1
521 // By default, don't trace bits for is_ext_suspend_completed() calls.
522 // That trace is very chatty.
523 return;
524 #else
525 if (!called_by_wait) {
526 // If tracing for is_ext_suspend_completed() is enabled, then only
527 // trace calls to it from wait_for_ext_suspend_completion()
528 return;
529 }
530 #endif
531 }
532
533 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
534 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
535 MutexLocker ml(Threads_lock); // needed for get_thread_name()
536 ResourceMark rm;
537
538 tty->print_cr(
539 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
540 jt->get_thread_name(), *bits);
541
542 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
543 }
544 }
545 }
546 };
547 #undef DEBUG_FALSE_BITS
548
549
550 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
551 uint32_t *bits) {
552 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
553
554 bool did_trans_retry = false; // only do thread_in_native_trans retry once
555 bool do_trans_retry; // flag to force the retry
556
557 *bits |= 0x00000001;
558
559 do {
560 do_trans_retry = false;
561
562 if (is_exiting()) {
563 // Thread is in the process of exiting. This is always checked
564 // first to reduce the risk of dereferencing a freed JavaThread.
565 *bits |= 0x00000100;
566 return false;
567 }
568
569 if (!is_external_suspend()) {
570 // Suspend request is cancelled. This is always checked before
571 // is_ext_suspended() to reduce the risk of a rogue resume
572 // confusing the thread that made the suspend request.
573 *bits |= 0x00000200;
574 return false;
575 }
576
577 if (is_ext_suspended()) {
578 // thread is suspended
579 *bits |= 0x00000400;
580 return true;
581 }
582
583 // Now that we no longer do hard suspends of threads running
584 // native code, the target thread can be changing thread state
585 // while we are in this routine:
586 //
587 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
588 //
589 // We save a copy of the thread state as observed at this moment
590 // and make our decision about suspend completeness based on the
591 // copy. This closes the race where the thread state is seen as
592 // _thread_in_native_trans in the if-thread_blocked check, but is
593 // seen as _thread_blocked in if-thread_in_native_trans check.
594 JavaThreadState save_state = thread_state();
595
596 if (save_state == _thread_blocked && is_suspend_equivalent()) {
597 // If the thread's state is _thread_blocked and this blocking
598 // condition is known to be equivalent to a suspend, then we can
599 // consider the thread to be externally suspended. This means that
600 // the code that sets _thread_blocked has been modified to do
601 // self-suspension if the blocking condition releases. We also
602 // used to check for CONDVAR_WAIT here, but that is now covered by
603 // the _thread_blocked with self-suspension check.
604 //
605 // Return true since we wouldn't be here unless there was still an
606 // external suspend request.
607 *bits |= 0x00001000;
608 return true;
609 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
610 // Threads running native code will self-suspend on native==>VM/Java
611 // transitions. If its stack is walkable (should always be the case
612 // unless this function is called before the actual java_suspend()
613 // call), then the wait is done.
614 *bits |= 0x00002000;
615 return true;
616 } else if (!called_by_wait && !did_trans_retry &&
617 save_state == _thread_in_native_trans &&
618 frame_anchor()->walkable()) {
619 // The thread is transitioning from thread_in_native to another
620 // thread state. check_safepoint_and_suspend_for_native_trans()
621 // will force the thread to self-suspend. If it hasn't gotten
622 // there yet we may have caught the thread in-between the native
623 // code check above and the self-suspend. Lucky us. If we were
624 // called by wait_for_ext_suspend_completion(), then it
625 // will be doing the retries so we don't have to.
626 //
627 // Since we use the saved thread state in the if-statement above,
628 // there is a chance that the thread has already transitioned to
629 // _thread_blocked by the time we get here. In that case, we will
630 // make a single unnecessary pass through the logic below. This
631 // doesn't hurt anything since we still do the trans retry.
632
633 *bits |= 0x00004000;
634
635 // Once the thread leaves thread_in_native_trans for another
636 // thread state, we break out of this retry loop. We shouldn't
637 // need this flag to prevent us from getting back here, but
638 // sometimes paranoia is good.
639 did_trans_retry = true;
640
641 // We wait for the thread to transition to a more usable state.
642 for (int i = 1; i <= SuspendRetryCount; i++) {
643 // We used to do an "os::yield_all(i)" call here with the intention
644 // that yielding would increase on each retry. However, the parameter
645 // is ignored on Linux which means the yield didn't scale up. Waiting
646 // on the SR_lock below provides a much more predictable scale up for
647 // the delay. It also provides a simple/direct point to check for any
648 // safepoint requests from the VMThread
649
650 // temporarily drops SR_lock while doing wait with safepoint check
651 // (if we're a JavaThread - the WatcherThread can also call this)
652 // and increase delay with each retry
653 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
654
655 // check the actual thread state instead of what we saved above
656 if (thread_state() != _thread_in_native_trans) {
657 // the thread has transitioned to another thread state so
658 // try all the checks (except this one) one more time.
659 do_trans_retry = true;
660 break;
661 }
662 } // end retry loop
663
664
665 }
666 } while (do_trans_retry);
667
668 *bits |= 0x00000010;
669 return false;
670 }
671
672 // Wait for an external suspend request to complete (or be cancelled).
673 // Returns true if the thread is externally suspended and false otherwise.
674 //
675 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
676 uint32_t *bits) {
677 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
678 false /* !called_by_wait */, bits);
679
680 // local flag copies to minimize SR_lock hold time
681 bool is_suspended;
682 bool pending;
683 uint32_t reset_bits;
684
685 // set a marker so is_ext_suspend_completed() knows we are the caller
686 *bits |= 0x00010000;
687
688 // We use reset_bits to reinitialize the bits value at the top of
689 // each retry loop. This allows the caller to make use of any
690 // unused bits for their own marking purposes.
691 reset_bits = *bits;
692
693 {
694 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
695 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
696 delay, bits);
697 pending = is_external_suspend();
698 }
699 // must release SR_lock to allow suspension to complete
700
701 if (!pending) {
702 // A cancelled suspend request is the only false return from
703 // is_ext_suspend_completed() that keeps us from entering the
704 // retry loop.
705 *bits |= 0x00020000;
706 return false;
707 }
708
709 if (is_suspended) {
710 *bits |= 0x00040000;
711 return true;
712 }
713
714 for (int i = 1; i <= retries; i++) {
715 *bits = reset_bits; // reinit to only track last retry
716
717 // We used to do an "os::yield_all(i)" call here with the intention
718 // that yielding would increase on each retry. However, the parameter
719 // is ignored on Linux which means the yield didn't scale up. Waiting
720 // on the SR_lock below provides a much more predictable scale up for
721 // the delay. It also provides a simple/direct point to check for any
722 // safepoint requests from the VMThread
723
724 {
725 MutexLocker ml(SR_lock());
726 // wait with safepoint check (if we're a JavaThread - the WatcherThread
727 // can also call this) and increase delay with each retry
728 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
729
730 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
731 delay, bits);
732
733 // It is possible for the external suspend request to be cancelled
734 // (by a resume) before the actual suspend operation is completed.
735 // Refresh our local copy to see if we still need to wait.
736 pending = is_external_suspend();
737 }
738
739 if (!pending) {
740 // A cancelled suspend request is the only false return from
741 // is_ext_suspend_completed() that keeps us from staying in the
742 // retry loop.
743 *bits |= 0x00080000;
744 return false;
745 }
746
747 if (is_suspended) {
748 *bits |= 0x00100000;
749 return true;
750 }
751 } // end retry loop
752
753 // thread did not suspend after all our retries
754 *bits |= 0x00200000;
755 return false;
756 }
757
758 // Called from API entry points which perform stack walking. If the
759 // associated JavaThread is the current thread, then wait_for_suspend
760 // is not used. Otherwise, it determines if we should wait for the
761 // "other" thread to complete external suspension. (NOTE: in future
762 // releases the suspension mechanism should be reimplemented so this
763 // is not necessary.)
764 //
765 bool
766 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) {
767 if (this != JavaThread::current()) {
768 // "other" threads require special handling.
769 if (wait_for_suspend) {
770 // We are allowed to wait for the external suspend to complete
771 // so give the other thread a chance to get suspended.
772 if (!wait_for_ext_suspend_completion(SuspendRetryCount,
773 SuspendRetryDelay, bits)) {
774 // Didn't make it so let the caller know.
775 return false;
776 }
777 }
778 // We aren't allowed to wait for the external suspend to complete
779 // so if the other thread isn't externally suspended we need to
780 // let the caller know.
781 else if (!is_ext_suspend_completed_with_lock(bits)) {
782 return false;
783 }
784 }
785
786 return true;
787 }
788
789 #ifndef PRODUCT
790 void JavaThread::record_jump(address target, address instr, const char* file,
791 int line) {
792
793 // This should not need to be atomic as the only way for simultaneous
794 // updates is via interrupts. Even then this should be rare or non-existent
795 // and we don't care that much anyway.
796
797 int index = _jmp_ring_index;
798 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
799 _jmp_ring[index]._target = (intptr_t) target;
800 _jmp_ring[index]._instruction = (intptr_t) instr;
801 _jmp_ring[index]._file = file;
802 _jmp_ring[index]._line = line;
803 }
804 #endif // PRODUCT
805
806 void Thread::interrupt(Thread* thread) {
807 debug_only(check_for_dangling_thread_pointer(thread);)
808 os::interrupt(thread);
809 }
810
811 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
812 debug_only(check_for_dangling_thread_pointer(thread);)
813 // Note: If clear_interrupted==false, this simply fetches and
814 // returns the value of the field osthread()->interrupted().
815 return os::is_interrupted(thread, clear_interrupted);
816 }
817
818
819 // GC Support
820 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
821 int thread_parity = _oops_do_parity;
822 if (thread_parity != strong_roots_parity) {
823 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
824 if (res == thread_parity) {
825 return true;
826 } else {
827 guarantee(res == strong_roots_parity, "Or else what?");
828 return false;
829 }
830 }
831 return false;
832 }
833
834 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
835 active_handles()->oops_do(f);
836 // Do oop for ThreadShadow
837 f->do_oop((oop*)&_pending_exception);
838 handle_area()->oops_do(f);
839
840 if (MonitorInUseLists) {
841 // When using thread local monitor lists, we scan them here,
842 // and the remaining global monitors in ObjectSynchronizer::oops_do().
843 ObjectSynchronizer::thread_local_used_oops_do(this, f);
844 }
845 }
846
847 void Thread::metadata_handles_do(void f(Metadata*)) {
848 // Only walk the Handles in Thread.
849 if (metadata_handles() != NULL) {
850 for (int i = 0; i< metadata_handles()->length(); i++) {
851 f(metadata_handles()->at(i));
852 }
853 }
854 }
855
856 void Thread::print_on(outputStream* st) const {
857 // get_priority assumes osthread initialized
858 if (osthread() != NULL) {
859 int os_prio;
860 if (os::get_native_priority(this, &os_prio) == OS_OK) {
861 st->print("os_prio=%d ", os_prio);
862 }
863 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
864 osthread()->print_on(st);
865 }
866 if (_threads_hazard_ptr != NULL) {
867 st->print("_threads_hazard_ptr=" INTPTR_FORMAT, p2i(_threads_hazard_ptr));
868 }
869 if (_nested_threads_hazard_ptr != NULL) {
870 print_nested_threads_hazard_ptrs_on(st);
871 }
872 st->print(" ");
873 debug_only(if (WizardMode) print_owned_locks_on(st);)
874 }
875
876 void Thread::print_nested_threads_hazard_ptrs_on(outputStream* st) const {
877 assert(_nested_threads_hazard_ptr != NULL, "must be set to print");
878
879 if (EnableThreadSMRStatistics) {
880 st->print(", _nested_threads_hazard_ptr_cnt=%u", _nested_threads_hazard_ptr_cnt);
881 }
882 st->print(", _nested_threads_hazard_ptrs=");
883 for (NestedThreadsList* node = _nested_threads_hazard_ptr; node != NULL;
884 node = node->next()) {
885 if (node != _nested_threads_hazard_ptr) {
886 // First node does not need a comma-space separator.
887 st->print(", ");
888 }
889 st->print(INTPTR_FORMAT, p2i(node->t_list()));
890 }
891 }
892
893 // Thread::print_on_error() is called by fatal error handler. Don't use
894 // any lock or allocate memory.
895 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
896 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
897
898 if (is_VM_thread()) { st->print("VMThread"); }
899 else if (is_GC_task_thread()) { st->print("GCTaskThread"); }
900 else if (is_Watcher_thread()) { st->print("WatcherThread"); }
901 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); }
902 else { st->print("Thread"); }
903
904 if (is_Named_thread()) {
905 st->print(" \"%s\"", name());
906 }
907
908 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
909 p2i(stack_end()), p2i(stack_base()));
910
911 if (osthread()) {
912 st->print(" [id=%d]", osthread()->thread_id());
913 }
914
915 if (_threads_hazard_ptr != NULL) {
916 st->print(" _threads_hazard_ptr=" INTPTR_FORMAT, p2i(_threads_hazard_ptr));
917 }
918 if (_nested_threads_hazard_ptr != NULL) {
919 print_nested_threads_hazard_ptrs_on(st);
920 }
921 }
922
923 void Thread::print_value_on(outputStream* st) const {
924 if (is_Named_thread()) {
925 st->print(" \"%s\" ", name());
926 }
927 st->print(INTPTR_FORMAT, p2i(this)); // print address
928 }
929
930 #ifdef ASSERT
931 void Thread::print_owned_locks_on(outputStream* st) const {
932 Monitor *cur = _owned_locks;
933 if (cur == NULL) {
934 st->print(" (no locks) ");
935 } else {
936 st->print_cr(" Locks owned:");
937 while (cur) {
938 cur->print_on(st);
939 cur = cur->next();
940 }
941 }
942 }
943
944 static int ref_use_count = 0;
945
946 bool Thread::owns_locks_but_compiled_lock() const {
947 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
948 if (cur != Compile_lock) return true;
949 }
950 return false;
951 }
952
953
954 #endif
955
956 #ifndef PRODUCT
957
958 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially
959 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that
960 // no threads which allow_vm_block's are held
961 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
962 // Check if current thread is allowed to block at a safepoint
963 if (!(_allow_safepoint_count == 0)) {
964 fatal("Possible safepoint reached by thread that does not allow it");
965 }
966 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
967 fatal("LEAF method calling lock?");
968 }
969
970 #ifdef ASSERT
971 if (potential_vm_operation && is_Java_thread()
972 && !Universe::is_bootstrapping()) {
973 // Make sure we do not hold any locks that the VM thread also uses.
974 // This could potentially lead to deadlocks
975 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
976 // Threads_lock is special, since the safepoint synchronization will not start before this is
977 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
978 // since it is used to transfer control between JavaThreads and the VMThread
979 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
980 if ((cur->allow_vm_block() &&
981 cur != Threads_lock &&
982 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
983 cur != VMOperationRequest_lock &&
984 cur != VMOperationQueue_lock) ||
985 cur->rank() == Mutex::special) {
986 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
987 }
988 }
989 }
990
991 if (GCALotAtAllSafepoints) {
992 // We could enter a safepoint here and thus have a gc
993 InterfaceSupport::check_gc_alot();
994 }
995 #endif
996 }
997 #endif
998
999 bool Thread::is_in_stack(address adr) const {
1000 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
1001 address end = os::current_stack_pointer();
1002 // Allow non Java threads to call this without stack_base
1003 if (_stack_base == NULL) return true;
1004 if (stack_base() >= adr && adr >= end) return true;
1005
1006 return false;
1007 }
1008
1009 bool Thread::is_in_usable_stack(address adr) const {
1010 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
1011 size_t usable_stack_size = _stack_size - stack_guard_size;
1012
1013 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
1014 }
1015
1016
1017 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
1018 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
1019 // used for compilation in the future. If that change is made, the need for these methods
1020 // should be revisited, and they should be removed if possible.
1021
1022 bool Thread::is_lock_owned(address adr) const {
1023 return on_local_stack(adr);
1024 }
1025
1026 bool Thread::set_as_starting_thread() {
1027 // NOTE: this must be called inside the main thread.
1028 return os::create_main_thread((JavaThread*)this);
1029 }
1030
1031 static void initialize_class(Symbol* class_name, TRAPS) {
1032 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
1033 InstanceKlass::cast(klass)->initialize(CHECK);
1034 }
1035
1036
1037 // Creates the initial ThreadGroup
1038 static Handle create_initial_thread_group(TRAPS) {
1039 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1040 InstanceKlass* ik = InstanceKlass::cast(k);
1041
1042 Handle system_instance = ik->allocate_instance_handle(CHECK_NH);
1043 {
1044 JavaValue result(T_VOID);
1045 JavaCalls::call_special(&result,
1046 system_instance,
1047 ik,
1048 vmSymbols::object_initializer_name(),
1049 vmSymbols::void_method_signature(),
1050 CHECK_NH);
1051 }
1052 Universe::set_system_thread_group(system_instance());
1053
1054 Handle main_instance = ik->allocate_instance_handle(CHECK_NH);
1055 {
1056 JavaValue result(T_VOID);
1057 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1058 JavaCalls::call_special(&result,
1059 main_instance,
1060 ik,
1061 vmSymbols::object_initializer_name(),
1062 vmSymbols::threadgroup_string_void_signature(),
1063 system_instance,
1064 string,
1065 CHECK_NH);
1066 }
1067 return main_instance;
1068 }
1069
1070 // Creates the initial Thread
1071 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1072 TRAPS) {
1073 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1074 InstanceKlass* ik = InstanceKlass::cast(k);
1075 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
1076
1077 java_lang_Thread::set_thread(thread_oop(), thread);
1078 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1079 thread->set_threadObj(thread_oop());
1080
1081 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1082
1083 JavaValue result(T_VOID);
1084 JavaCalls::call_special(&result, thread_oop,
1085 ik,
1086 vmSymbols::object_initializer_name(),
1087 vmSymbols::threadgroup_string_void_signature(),
1088 thread_group,
1089 string,
1090 CHECK_NULL);
1091 return thread_oop();
1092 }
1093
1094 char java_runtime_name[128] = "";
1095 char java_runtime_version[128] = "";
1096
1097 // extract the JRE name from java.lang.VersionProps.java_runtime_name
1098 static const char* get_java_runtime_name(TRAPS) {
1099 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1100 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1101 fieldDescriptor fd;
1102 bool found = k != NULL &&
1103 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1104 vmSymbols::string_signature(), &fd);
1105 if (found) {
1106 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1107 if (name_oop == NULL) {
1108 return NULL;
1109 }
1110 const char* name = java_lang_String::as_utf8_string(name_oop,
1111 java_runtime_name,
1112 sizeof(java_runtime_name));
1113 return name;
1114 } else {
1115 return NULL;
1116 }
1117 }
1118
1119 // extract the JRE version from java.lang.VersionProps.java_runtime_version
1120 static const char* get_java_runtime_version(TRAPS) {
1121 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
1122 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1123 fieldDescriptor fd;
1124 bool found = k != NULL &&
1125 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1126 vmSymbols::string_signature(), &fd);
1127 if (found) {
1128 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1129 if (name_oop == NULL) {
1130 return NULL;
1131 }
1132 const char* name = java_lang_String::as_utf8_string(name_oop,
1133 java_runtime_version,
1134 sizeof(java_runtime_version));
1135 return name;
1136 } else {
1137 return NULL;
1138 }
1139 }
1140
1141 // General purpose hook into Java code, run once when the VM is initialized.
1142 // The Java library method itself may be changed independently from the VM.
1143 static void call_postVMInitHook(TRAPS) {
1144 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
1145 if (klass != NULL) {
1146 JavaValue result(T_VOID);
1147 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1148 vmSymbols::void_method_signature(),
1149 CHECK);
1150 }
1151 }
1152
1153 static void reset_vm_info_property(TRAPS) {
1154 // the vm info string
1155 ResourceMark rm(THREAD);
1156 const char *vm_info = VM_Version::vm_info_string();
1157
1158 // java.lang.System class
1159 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1160
1161 // setProperty arguments
1162 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1163 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1164
1165 // return value
1166 JavaValue r(T_OBJECT);
1167
1168 // public static String setProperty(String key, String value);
1169 JavaCalls::call_static(&r,
1170 klass,
1171 vmSymbols::setProperty_name(),
1172 vmSymbols::string_string_string_signature(),
1173 key_str,
1174 value_str,
1175 CHECK);
1176 }
1177
1178
1179 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1180 bool daemon, TRAPS) {
1181 assert(thread_group.not_null(), "thread group should be specified");
1182 assert(threadObj() == NULL, "should only create Java thread object once");
1183
1184 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1185 InstanceKlass* ik = InstanceKlass::cast(k);
1186 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
1187
1188 java_lang_Thread::set_thread(thread_oop(), this);
1189 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1190 set_threadObj(thread_oop());
1191
1192 JavaValue result(T_VOID);
1193 if (thread_name != NULL) {
1194 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1195 // Thread gets assigned specified name and null target
1196 JavaCalls::call_special(&result,
1197 thread_oop,
1198 ik,
1199 vmSymbols::object_initializer_name(),
1200 vmSymbols::threadgroup_string_void_signature(),
1201 thread_group, // Argument 1
1202 name, // Argument 2
1203 THREAD);
1204 } else {
1205 // Thread gets assigned name "Thread-nnn" and null target
1206 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1207 JavaCalls::call_special(&result,
1208 thread_oop,
1209 ik,
1210 vmSymbols::object_initializer_name(),
1211 vmSymbols::threadgroup_runnable_void_signature(),
1212 thread_group, // Argument 1
1213 Handle(), // Argument 2
1214 THREAD);
1215 }
1216
1217
1218 if (daemon) {
1219 java_lang_Thread::set_daemon(thread_oop());
1220 }
1221
1222 if (HAS_PENDING_EXCEPTION) {
1223 return;
1224 }
1225
1226 Klass* group = SystemDictionary::ThreadGroup_klass();
1227 Handle threadObj(THREAD, this->threadObj());
1228
1229 JavaCalls::call_special(&result,
1230 thread_group,
1231 group,
1232 vmSymbols::add_method_name(),
1233 vmSymbols::thread_void_signature(),
1234 threadObj, // Arg 1
1235 THREAD);
1236 }
1237
1238 // NamedThread -- non-JavaThread subclasses with multiple
1239 // uniquely named instances should derive from this.
1240 NamedThread::NamedThread() : Thread() {
1241 _name = NULL;
1242 _processed_thread = NULL;
1243 _gc_id = GCId::undefined();
1244 }
1245
1246 NamedThread::~NamedThread() {
1247 if (_name != NULL) {
1248 FREE_C_HEAP_ARRAY(char, _name);
1249 _name = NULL;
1250 }
1251 }
1252
1253 void NamedThread::set_name(const char* format, ...) {
1254 guarantee(_name == NULL, "Only get to set name once.");
1255 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1256 guarantee(_name != NULL, "alloc failure");
1257 va_list ap;
1258 va_start(ap, format);
1259 jio_vsnprintf(_name, max_name_len, format, ap);
1260 va_end(ap);
1261 }
1262
1263 void NamedThread::initialize_named_thread() {
1264 set_native_thread_name(name());
1265 }
1266
1267 void NamedThread::print_on(outputStream* st) const {
1268 st->print("\"%s\" ", name());
1269 Thread::print_on(st);
1270 st->cr();
1271 }
1272
1273
1274 // ======= WatcherThread ========
1275
1276 // The watcher thread exists to simulate timer interrupts. It should
1277 // be replaced by an abstraction over whatever native support for
1278 // timer interrupts exists on the platform.
1279
1280 WatcherThread* WatcherThread::_watcher_thread = NULL;
1281 bool WatcherThread::_startable = false;
1282 volatile bool WatcherThread::_should_terminate = false;
1283
1284 WatcherThread::WatcherThread() : Thread() {
1285 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1286 if (os::create_thread(this, os::watcher_thread)) {
1287 _watcher_thread = this;
1288
1289 // Set the watcher thread to the highest OS priority which should not be
1290 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1291 // is created. The only normal thread using this priority is the reference
1292 // handler thread, which runs for very short intervals only.
1293 // If the VMThread's priority is not lower than the WatcherThread profiling
1294 // will be inaccurate.
1295 os::set_priority(this, MaxPriority);
1296 if (!DisableStartThread) {
1297 os::start_thread(this);
1298 }
1299 }
1300 }
1301
1302 int WatcherThread::sleep() const {
1303 // The WatcherThread does not participate in the safepoint protocol
1304 // for the PeriodicTask_lock because it is not a JavaThread.
1305 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1306
1307 if (_should_terminate) {
1308 // check for termination before we do any housekeeping or wait
1309 return 0; // we did not sleep.
1310 }
1311
1312 // remaining will be zero if there are no tasks,
1313 // causing the WatcherThread to sleep until a task is
1314 // enrolled
1315 int remaining = PeriodicTask::time_to_wait();
1316 int time_slept = 0;
1317
1318 // we expect this to timeout - we only ever get unparked when
1319 // we should terminate or when a new task has been enrolled
1320 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1321
1322 jlong time_before_loop = os::javaTimeNanos();
1323
1324 while (true) {
1325 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1326 remaining);
1327 jlong now = os::javaTimeNanos();
1328
1329 if (remaining == 0) {
1330 // if we didn't have any tasks we could have waited for a long time
1331 // consider the time_slept zero and reset time_before_loop
1332 time_slept = 0;
1333 time_before_loop = now;
1334 } else {
1335 // need to recalculate since we might have new tasks in _tasks
1336 time_slept = (int) ((now - time_before_loop) / 1000000);
1337 }
1338
1339 // Change to task list or spurious wakeup of some kind
1340 if (timedout || _should_terminate) {
1341 break;
1342 }
1343
1344 remaining = PeriodicTask::time_to_wait();
1345 if (remaining == 0) {
1346 // Last task was just disenrolled so loop around and wait until
1347 // another task gets enrolled
1348 continue;
1349 }
1350
1351 remaining -= time_slept;
1352 if (remaining <= 0) {
1353 break;
1354 }
1355 }
1356
1357 return time_slept;
1358 }
1359
1360 void WatcherThread::run() {
1361 assert(this == watcher_thread(), "just checking");
1362
1363 this->record_stack_base_and_size();
1364 this->set_native_thread_name(this->name());
1365 this->set_active_handles(JNIHandleBlock::allocate_block());
1366 while (true) {
1367 assert(watcher_thread() == Thread::current(), "thread consistency check");
1368 assert(watcher_thread() == this, "thread consistency check");
1369
1370 // Calculate how long it'll be until the next PeriodicTask work
1371 // should be done, and sleep that amount of time.
1372 int time_waited = sleep();
1373
1374 if (VMError::is_error_reported()) {
1375 // A fatal error has happened, the error handler(VMError::report_and_die)
1376 // should abort JVM after creating an error log file. However in some
1377 // rare cases, the error handler itself might deadlock. Here periodically
1378 // check for error reporting timeouts, and if it happens, just proceed to
1379 // abort the VM.
1380
1381 // This code is in WatcherThread because WatcherThread wakes up
1382 // periodically so the fatal error handler doesn't need to do anything;
1383 // also because the WatcherThread is less likely to crash than other
1384 // threads.
1385
1386 for (;;) {
1387 // Note: we use naked sleep in this loop because we want to avoid using
1388 // any kind of VM infrastructure which may be broken at this point.
1389 if (VMError::check_timeout()) {
1390 // We hit error reporting timeout. Error reporting was interrupted and
1391 // will be wrapping things up now (closing files etc). Give it some more
1392 // time, then quit the VM.
1393 os::naked_short_sleep(200);
1394 // Print a message to stderr.
1395 fdStream err(defaultStream::output_fd());
1396 err.print_raw_cr("# [ timer expired, abort... ]");
1397 // skip atexit/vm_exit/vm_abort hooks
1398 os::die();
1399 }
1400
1401 // Wait a second, then recheck for timeout.
1402 os::naked_short_sleep(999);
1403 }
1404 }
1405
1406 if (_should_terminate) {
1407 // check for termination before posting the next tick
1408 break;
1409 }
1410
1411 PeriodicTask::real_time_tick(time_waited);
1412 }
1413
1414 // Signal that it is terminated
1415 {
1416 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1417 _watcher_thread = NULL;
1418 Terminator_lock->notify();
1419 }
1420 }
1421
1422 void WatcherThread::start() {
1423 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1424
1425 if (watcher_thread() == NULL && _startable) {
1426 _should_terminate = false;
1427 // Create the single instance of WatcherThread
1428 new WatcherThread();
1429 }
1430 }
1431
1432 void WatcherThread::make_startable() {
1433 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1434 _startable = true;
1435 }
1436
1437 void WatcherThread::stop() {
1438 {
1439 // Follow normal safepoint aware lock enter protocol since the
1440 // WatcherThread is stopped by another JavaThread.
1441 MutexLocker ml(PeriodicTask_lock);
1442 _should_terminate = true;
1443
1444 WatcherThread* watcher = watcher_thread();
1445 if (watcher != NULL) {
1446 // unpark the WatcherThread so it can see that it should terminate
1447 watcher->unpark();
1448 }
1449 }
1450
1451 MutexLocker mu(Terminator_lock);
1452
1453 while (watcher_thread() != NULL) {
1454 // This wait should make safepoint checks, wait without a timeout,
1455 // and wait as a suspend-equivalent condition.
1456 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1457 Mutex::_as_suspend_equivalent_flag);
1458 }
1459 }
1460
1461 void WatcherThread::unpark() {
1462 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1463 PeriodicTask_lock->notify();
1464 }
1465
1466 void WatcherThread::print_on(outputStream* st) const {
1467 st->print("\"%s\" ", name());
1468 Thread::print_on(st);
1469 st->cr();
1470 }
1471
1472 // ======= JavaThread ========
1473
1474 #if INCLUDE_JVMCI
1475
1476 jlong* JavaThread::_jvmci_old_thread_counters;
1477
1478 bool jvmci_counters_include(JavaThread* thread) {
1479 oop threadObj = thread->threadObj();
1480 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1481 }
1482
1483 void JavaThread::collect_counters(typeArrayOop array) {
1484 if (JVMCICounterSize > 0) {
1485 MutexLocker tl(Threads_lock);
1486 JavaThreadIteratorWithHandle jtiwh;
1487 for (int i = 0; i < array->length(); i++) {
1488 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1489 }
1490 for (; JavaThread *tp = jtiwh.next(); ) {
1491 if (jvmci_counters_include(tp)) {
1492 for (int i = 0; i < array->length(); i++) {
1493 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1494 }
1495 }
1496 }
1497 }
1498 }
1499
1500 #endif // INCLUDE_JVMCI
1501
1502 // A JavaThread is a normal Java thread
1503
1504 void JavaThread::initialize() {
1505 // Initialize fields
1506
1507 set_saved_exception_pc(NULL);
1508 set_threadObj(NULL);
1509 _anchor.clear();
1510 set_entry_point(NULL);
1511 set_jni_functions(jni_functions());
1512 set_callee_target(NULL);
1513 set_vm_result(NULL);
1514 set_vm_result_2(NULL);
1515 set_vframe_array_head(NULL);
1516 set_vframe_array_last(NULL);
1517 set_deferred_locals(NULL);
1518 set_deopt_mark(NULL);
1519 set_deopt_compiled_method(NULL);
1520 clear_must_deopt_id();
1521 set_monitor_chunks(NULL);
1522 set_next(NULL);
1523 _on_thread_list = false;
1524 set_thread_state(_thread_new);
1525 _terminated = _not_terminated;
1526 _privileged_stack_top = NULL;
1527 _array_for_gc = NULL;
1528 _suspend_equivalent = false;
1529 _in_deopt_handler = 0;
1530 _doing_unsafe_access = false;
1531 _stack_guard_state = stack_guard_unused;
1532 #if INCLUDE_JVMCI
1533 _pending_monitorenter = false;
1534 _pending_deoptimization = -1;
1535 _pending_failed_speculation = NULL;
1536 _pending_transfer_to_interpreter = false;
1537 _adjusting_comp_level = false;
1538 _jvmci._alternate_call_target = NULL;
1539 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1540 if (JVMCICounterSize > 0) {
1541 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1542 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1543 } else {
1544 _jvmci_counters = NULL;
1545 }
1546 #endif // INCLUDE_JVMCI
1547 _reserved_stack_activation = NULL; // stack base not known yet
1548 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1549 _exception_pc = 0;
1550 _exception_handler_pc = 0;
1551 _is_method_handle_return = 0;
1552 _jvmti_thread_state= NULL;
1553 _should_post_on_exceptions_flag = JNI_FALSE;
1554 _jvmti_get_loaded_classes_closure = NULL;
1555 _interp_only_mode = 0;
1556 _special_runtime_exit_condition = _no_async_condition;
1557 _pending_async_exception = NULL;
1558 _thread_stat = NULL;
1559 _thread_stat = new ThreadStatistics();
1560 _blocked_on_compilation = false;
1561 _jni_active_critical = 0;
1562 _pending_jni_exception_check_fn = NULL;
1563 _do_not_unlock_if_synchronized = false;
1564 _cached_monitor_info = NULL;
1565 _parker = Parker::Allocate(this);
1566
1567 #ifndef PRODUCT
1568 _jmp_ring_index = 0;
1569 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1570 record_jump(NULL, NULL, NULL, 0);
1571 }
1572 #endif // PRODUCT
1573
1574 // Setup safepoint state info for this thread
1575 ThreadSafepointState::create(this);
1576
1577 debug_only(_java_call_counter = 0);
1578
1579 // JVMTI PopFrame support
1580 _popframe_condition = popframe_inactive;
1581 _popframe_preserved_args = NULL;
1582 _popframe_preserved_args_size = 0;
1583 _frames_to_pop_failed_realloc = 0;
1584
1585 if (SafepointMechanism::uses_thread_local_poll()) {
1586 SafepointMechanism::initialize_header(this);
1587 }
1588
1589 pd_initialize();
1590 }
1591
1592 #if INCLUDE_ALL_GCS
1593 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1594 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1595 #endif // INCLUDE_ALL_GCS
1596
1597 JavaThread::JavaThread(bool is_attaching_via_jni) :
1598 Thread()
1599 #if INCLUDE_ALL_GCS
1600 , _satb_mark_queue(&_satb_mark_queue_set),
1601 _dirty_card_queue(&_dirty_card_queue_set)
1602 #endif // INCLUDE_ALL_GCS
1603 {
1604 initialize();
1605 if (is_attaching_via_jni) {
1606 _jni_attach_state = _attaching_via_jni;
1607 } else {
1608 _jni_attach_state = _not_attaching_via_jni;
1609 }
1610 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1611 }
1612
1613 bool JavaThread::reguard_stack(address cur_sp) {
1614 if (_stack_guard_state != stack_guard_yellow_reserved_disabled
1615 && _stack_guard_state != stack_guard_reserved_disabled) {
1616 return true; // Stack already guarded or guard pages not needed.
1617 }
1618
1619 if (register_stack_overflow()) {
1620 // For those architectures which have separate register and
1621 // memory stacks, we must check the register stack to see if
1622 // it has overflowed.
1623 return false;
1624 }
1625
1626 // Java code never executes within the yellow zone: the latter is only
1627 // there to provoke an exception during stack banging. If java code
1628 // is executing there, either StackShadowPages should be larger, or
1629 // some exception code in c1, c2 or the interpreter isn't unwinding
1630 // when it should.
1631 guarantee(cur_sp > stack_reserved_zone_base(),
1632 "not enough space to reguard - increase StackShadowPages");
1633 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
1634 enable_stack_yellow_reserved_zone();
1635 if (reserved_stack_activation() != stack_base()) {
1636 set_reserved_stack_activation(stack_base());
1637 }
1638 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1639 set_reserved_stack_activation(stack_base());
1640 enable_stack_reserved_zone();
1641 }
1642 return true;
1643 }
1644
1645 bool JavaThread::reguard_stack(void) {
1646 return reguard_stack(os::current_stack_pointer());
1647 }
1648
1649
1650 void JavaThread::block_if_vm_exited() {
1651 if (_terminated == _vm_exited) {
1652 // _vm_exited is set at safepoint, and Threads_lock is never released
1653 // we will block here forever
1654 Threads_lock->lock_without_safepoint_check();
1655 ShouldNotReachHere();
1656 }
1657 }
1658
1659
1660 // Remove this ifdef when C1 is ported to the compiler interface.
1661 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1662 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1663
1664 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1665 Thread()
1666 #if INCLUDE_ALL_GCS
1667 , _satb_mark_queue(&_satb_mark_queue_set),
1668 _dirty_card_queue(&_dirty_card_queue_set)
1669 #endif // INCLUDE_ALL_GCS
1670 {
1671 initialize();
1672 _jni_attach_state = _not_attaching_via_jni;
1673 set_entry_point(entry_point);
1674 // Create the native thread itself.
1675 // %note runtime_23
1676 os::ThreadType thr_type = os::java_thread;
1677 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1678 os::java_thread;
1679 os::create_thread(this, thr_type, stack_sz);
1680 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1681 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1682 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1683 // the exception consists of creating the exception object & initializing it, initialization
1684 // will leave the VM via a JavaCall and then all locks must be unlocked).
1685 //
1686 // The thread is still suspended when we reach here. Thread must be explicit started
1687 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1688 // by calling Threads:add. The reason why this is not done here, is because the thread
1689 // object must be fully initialized (take a look at JVM_Start)
1690 }
1691
1692 JavaThread::~JavaThread() {
1693
1694 // JSR166 -- return the parker to the free list
1695 Parker::Release(_parker);
1696 _parker = NULL;
1697
1698 // Free any remaining previous UnrollBlock
1699 vframeArray* old_array = vframe_array_last();
1700
1701 if (old_array != NULL) {
1702 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1703 old_array->set_unroll_block(NULL);
1704 delete old_info;
1705 delete old_array;
1706 }
1707
1708 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1709 if (deferred != NULL) {
1710 // This can only happen if thread is destroyed before deoptimization occurs.
1711 assert(deferred->length() != 0, "empty array!");
1712 do {
1713 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1714 deferred->remove_at(0);
1715 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1716 delete dlv;
1717 } while (deferred->length() != 0);
1718 delete deferred;
1719 }
1720
1721 // All Java related clean up happens in exit
1722 ThreadSafepointState::destroy(this);
1723 if (_thread_stat != NULL) delete _thread_stat;
1724
1725 #if INCLUDE_JVMCI
1726 if (JVMCICounterSize > 0) {
1727 if (jvmci_counters_include(this)) {
1728 for (int i = 0; i < JVMCICounterSize; i++) {
1729 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1730 }
1731 }
1732 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1733 }
1734 #endif // INCLUDE_JVMCI
1735 }
1736
1737
1738 // The first routine called by a new Java thread
1739 void JavaThread::run() {
1740 // initialize thread-local alloc buffer related fields
1741 this->initialize_tlab();
1742
1743 // used to test validity of stack trace backs
1744 this->record_base_of_stack_pointer();
1745
1746 // Record real stack base and size.
1747 this->record_stack_base_and_size();
1748
1749 this->create_stack_guard_pages();
1750
1751 this->cache_global_variables();
1752
1753 // Thread is now sufficient initialized to be handled by the safepoint code as being
1754 // in the VM. Change thread state from _thread_new to _thread_in_vm
1755 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1756
1757 assert(JavaThread::current() == this, "sanity check");
1758 assert(!Thread::current()->owns_locks(), "sanity check");
1759
1760 DTRACE_THREAD_PROBE(start, this);
1761
1762 // This operation might block. We call that after all safepoint checks for a new thread has
1763 // been completed.
1764 this->set_active_handles(JNIHandleBlock::allocate_block());
1765
1766 if (JvmtiExport::should_post_thread_life()) {
1767 JvmtiExport::post_thread_start(this);
1768 }
1769
1770 EventThreadStart event;
1771 if (event.should_commit()) {
1772 event.set_thread(THREAD_TRACE_ID(this));
1773 event.commit();
1774 }
1775
1776 // We call another function to do the rest so we are sure that the stack addresses used
1777 // from there will be lower than the stack base just computed
1778 thread_main_inner();
1779
1780 // Note, thread is no longer valid at this point!
1781 }
1782
1783
1784 void JavaThread::thread_main_inner() {
1785 assert(JavaThread::current() == this, "sanity check");
1786 assert(this->threadObj() != NULL, "just checking");
1787
1788 // Execute thread entry point unless this thread has a pending exception
1789 // or has been stopped before starting.
1790 // Note: Due to JVM_StopThread we can have pending exceptions already!
1791 if (!this->has_pending_exception() &&
1792 !java_lang_Thread::is_stillborn(this->threadObj())) {
1793 {
1794 ResourceMark rm(this);
1795 this->set_native_thread_name(this->get_thread_name());
1796 }
1797 HandleMark hm(this);
1798 this->entry_point()(this, this);
1799 }
1800
1801 DTRACE_THREAD_PROBE(stop, this);
1802
1803 this->exit(false);
1804 this->smr_delete();
1805 }
1806
1807
1808 static void ensure_join(JavaThread* thread) {
1809 // We do not need to grab the Threads_lock, since we are operating on ourself.
1810 Handle threadObj(thread, thread->threadObj());
1811 assert(threadObj.not_null(), "java thread object must exist");
1812 ObjectLocker lock(threadObj, thread);
1813 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1814 thread->clear_pending_exception();
1815 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1816 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1817 // Clear the native thread instance - this makes isAlive return false and allows the join()
1818 // to complete once we've done the notify_all below
1819 java_lang_Thread::set_thread(threadObj(), NULL);
1820 lock.notify_all(thread);
1821 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1822 thread->clear_pending_exception();
1823 }
1824
1825
1826 // For any new cleanup additions, please check to see if they need to be applied to
1827 // cleanup_failed_attach_current_thread as well.
1828 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1829 assert(this == JavaThread::current(), "thread consistency check");
1830
1831 elapsedTimer _timer_exit_phase1;
1832 elapsedTimer _timer_exit_phase2;
1833 elapsedTimer _timer_exit_phase3;
1834 elapsedTimer _timer_exit_phase4;
1835
1836 if (log_is_enabled(Debug, os, thread, timer)) {
1837 _timer_exit_phase1.start();
1838 }
1839
1840 HandleMark hm(this);
1841 Handle uncaught_exception(this, this->pending_exception());
1842 this->clear_pending_exception();
1843 Handle threadObj(this, this->threadObj());
1844 assert(threadObj.not_null(), "Java thread object should be created");
1845
1846 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1847 {
1848 EXCEPTION_MARK;
1849
1850 CLEAR_PENDING_EXCEPTION;
1851 }
1852 if (!destroy_vm) {
1853 if (uncaught_exception.not_null()) {
1854 EXCEPTION_MARK;
1855 // Call method Thread.dispatchUncaughtException().
1856 Klass* thread_klass = SystemDictionary::Thread_klass();
1857 JavaValue result(T_VOID);
1858 JavaCalls::call_virtual(&result,
1859 threadObj, thread_klass,
1860 vmSymbols::dispatchUncaughtException_name(),
1861 vmSymbols::throwable_void_signature(),
1862 uncaught_exception,
1863 THREAD);
1864 if (HAS_PENDING_EXCEPTION) {
1865 ResourceMark rm(this);
1866 jio_fprintf(defaultStream::error_stream(),
1867 "\nException: %s thrown from the UncaughtExceptionHandler"
1868 " in thread \"%s\"\n",
1869 pending_exception()->klass()->external_name(),
1870 get_thread_name());
1871 CLEAR_PENDING_EXCEPTION;
1872 }
1873 }
1874
1875 // Called before the java thread exit since we want to read info
1876 // from java_lang_Thread object
1877 EventThreadEnd event;
1878 if (event.should_commit()) {
1879 event.set_thread(THREAD_TRACE_ID(this));
1880 event.commit();
1881 }
1882
1883 // Call after last event on thread
1884 EVENT_THREAD_EXIT(this);
1885
1886 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1887 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1888 // is deprecated anyhow.
1889 if (!is_Compiler_thread()) {
1890 int count = 3;
1891 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1892 EXCEPTION_MARK;
1893 JavaValue result(T_VOID);
1894 Klass* thread_klass = SystemDictionary::Thread_klass();
1895 JavaCalls::call_virtual(&result,
1896 threadObj, thread_klass,
1897 vmSymbols::exit_method_name(),
1898 vmSymbols::void_method_signature(),
1899 THREAD);
1900 CLEAR_PENDING_EXCEPTION;
1901 }
1902 }
1903 // notify JVMTI
1904 if (JvmtiExport::should_post_thread_life()) {
1905 JvmtiExport::post_thread_end(this);
1906 }
1907
1908 // We have notified the agents that we are exiting, before we go on,
1909 // we must check for a pending external suspend request and honor it
1910 // in order to not surprise the thread that made the suspend request.
1911 while (true) {
1912 {
1913 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1914 if (!is_external_suspend()) {
1915 set_terminated(_thread_exiting);
1916 ThreadService::current_thread_exiting(this);
1917 break;
1918 }
1919 // Implied else:
1920 // Things get a little tricky here. We have a pending external
1921 // suspend request, but we are holding the SR_lock so we
1922 // can't just self-suspend. So we temporarily drop the lock
1923 // and then self-suspend.
1924 }
1925
1926 ThreadBlockInVM tbivm(this);
1927 java_suspend_self();
1928
1929 // We're done with this suspend request, but we have to loop around
1930 // and check again. Eventually we will get SR_lock without a pending
1931 // external suspend request and will be able to mark ourselves as
1932 // exiting.
1933 }
1934 // no more external suspends are allowed at this point
1935 } else {
1936 // before_exit() has already posted JVMTI THREAD_END events
1937 }
1938
1939 if (log_is_enabled(Debug, os, thread, timer)) {
1940 _timer_exit_phase1.stop();
1941 _timer_exit_phase2.start();
1942 }
1943 // Notify waiters on thread object. This has to be done after exit() is called
1944 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1945 // group should have the destroyed bit set before waiters are notified).
1946 ensure_join(this);
1947 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1948
1949 if (log_is_enabled(Debug, os, thread, timer)) {
1950 _timer_exit_phase2.stop();
1951 _timer_exit_phase3.start();
1952 }
1953 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1954 // held by this thread must be released. The spec does not distinguish
1955 // between JNI-acquired and regular Java monitors. We can only see
1956 // regular Java monitors here if monitor enter-exit matching is broken.
1957 //
1958 // Optionally release any monitors for regular JavaThread exits. This
1959 // is provided as a work around for any bugs in monitor enter-exit
1960 // matching. This can be expensive so it is not enabled by default.
1961 //
1962 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1963 // ObjectSynchronizer::release_monitors_owned_by_thread().
1964 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) {
1965 // Sanity check even though JNI DetachCurrentThread() would have
1966 // returned JNI_ERR if there was a Java frame. JavaThread exit
1967 // should be done executing Java code by the time we get here.
1968 assert(!this->has_last_Java_frame(),
1969 "should not have a Java frame when detaching or exiting");
1970 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1971 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1972 }
1973
1974 // These things needs to be done while we are still a Java Thread. Make sure that thread
1975 // is in a consistent state, in case GC happens
1976 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1977
1978 if (active_handles() != NULL) {
1979 JNIHandleBlock* block = active_handles();
1980 set_active_handles(NULL);
1981 JNIHandleBlock::release_block(block);
1982 }
1983
1984 if (free_handle_block() != NULL) {
1985 JNIHandleBlock* block = free_handle_block();
1986 set_free_handle_block(NULL);
1987 JNIHandleBlock::release_block(block);
1988 }
1989
1990 // These have to be removed while this is still a valid thread.
1991 remove_stack_guard_pages();
1992
1993 if (UseTLAB) {
1994 tlab().make_parsable(true); // retire TLAB
1995 }
1996
1997 if (JvmtiEnv::environments_might_exist()) {
1998 JvmtiExport::cleanup_thread(this);
1999 }
2000
2001 // We must flush any deferred card marks and other various GC barrier
2002 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
2003 // before removing a thread from the list of active threads.
2004 BarrierSet::barrier_set()->on_thread_detach(this);
2005
2006 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
2007 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
2008 os::current_thread_id());
2009
2010 if (log_is_enabled(Debug, os, thread, timer)) {
2011 _timer_exit_phase3.stop();
2012 _timer_exit_phase4.start();
2013 }
2014 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
2015 Threads::remove(this);
2016
2017 if (log_is_enabled(Debug, os, thread, timer)) {
2018 _timer_exit_phase4.stop();
2019 ResourceMark rm(this);
2020 log_debug(os, thread, timer)("name='%s'"
2021 ", exit-phase1=" JLONG_FORMAT
2022 ", exit-phase2=" JLONG_FORMAT
2023 ", exit-phase3=" JLONG_FORMAT
2024 ", exit-phase4=" JLONG_FORMAT,
2025 get_thread_name(),
2026 _timer_exit_phase1.milliseconds(),
2027 _timer_exit_phase2.milliseconds(),
2028 _timer_exit_phase3.milliseconds(),
2029 _timer_exit_phase4.milliseconds());
2030 }
2031 }
2032
2033 void JavaThread::cleanup_failed_attach_current_thread() {
2034 if (active_handles() != NULL) {
2035 JNIHandleBlock* block = active_handles();
2036 set_active_handles(NULL);
2037 JNIHandleBlock::release_block(block);
2038 }
2039
2040 if (free_handle_block() != NULL) {
2041 JNIHandleBlock* block = free_handle_block();
2042 set_free_handle_block(NULL);
2043 JNIHandleBlock::release_block(block);
2044 }
2045
2046 // These have to be removed while this is still a valid thread.
2047 remove_stack_guard_pages();
2048
2049 if (UseTLAB) {
2050 tlab().make_parsable(true); // retire TLAB, if any
2051 }
2052
2053 BarrierSet::barrier_set()->on_thread_detach(this);
2054
2055 Threads::remove(this);
2056 this->smr_delete();
2057 }
2058
2059 JavaThread* JavaThread::active() {
2060 Thread* thread = Thread::current();
2061 if (thread->is_Java_thread()) {
2062 return (JavaThread*) thread;
2063 } else {
2064 assert(thread->is_VM_thread(), "this must be a vm thread");
2065 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2066 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2067 assert(ret->is_Java_thread(), "must be a Java thread");
2068 return ret;
2069 }
2070 }
2071
2072 bool JavaThread::is_lock_owned(address adr) const {
2073 if (Thread::is_lock_owned(adr)) return true;
2074
2075 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2076 if (chunk->contains(adr)) return true;
2077 }
2078
2079 return false;
2080 }
2081
2082
2083 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2084 chunk->set_next(monitor_chunks());
2085 set_monitor_chunks(chunk);
2086 }
2087
2088 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2089 guarantee(monitor_chunks() != NULL, "must be non empty");
2090 if (monitor_chunks() == chunk) {
2091 set_monitor_chunks(chunk->next());
2092 } else {
2093 MonitorChunk* prev = monitor_chunks();
2094 while (prev->next() != chunk) prev = prev->next();
2095 prev->set_next(chunk->next());
2096 }
2097 }
2098
2099 // JVM support.
2100
2101 // Note: this function shouldn't block if it's called in
2102 // _thread_in_native_trans state (such as from
2103 // check_special_condition_for_native_trans()).
2104 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2105
2106 if (has_last_Java_frame() && has_async_condition()) {
2107 // If we are at a polling page safepoint (not a poll return)
2108 // then we must defer async exception because live registers
2109 // will be clobbered by the exception path. Poll return is
2110 // ok because the call we a returning from already collides
2111 // with exception handling registers and so there is no issue.
2112 // (The exception handling path kills call result registers but
2113 // this is ok since the exception kills the result anyway).
2114
2115 if (is_at_poll_safepoint()) {
2116 // if the code we are returning to has deoptimized we must defer
2117 // the exception otherwise live registers get clobbered on the
2118 // exception path before deoptimization is able to retrieve them.
2119 //
2120 RegisterMap map(this, false);
2121 frame caller_fr = last_frame().sender(&map);
2122 assert(caller_fr.is_compiled_frame(), "what?");
2123 if (caller_fr.is_deoptimized_frame()) {
2124 log_info(exceptions)("deferred async exception at compiled safepoint");
2125 return;
2126 }
2127 }
2128 }
2129
2130 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2131 if (condition == _no_async_condition) {
2132 // Conditions have changed since has_special_runtime_exit_condition()
2133 // was called:
2134 // - if we were here only because of an external suspend request,
2135 // then that was taken care of above (or cancelled) so we are done
2136 // - if we were here because of another async request, then it has
2137 // been cleared between the has_special_runtime_exit_condition()
2138 // and now so again we are done
2139 return;
2140 }
2141
2142 // Check for pending async. exception
2143 if (_pending_async_exception != NULL) {
2144 // Only overwrite an already pending exception, if it is not a threadDeath.
2145 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2146
2147 // We cannot call Exceptions::_throw(...) here because we cannot block
2148 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2149
2150 LogTarget(Info, exceptions) lt;
2151 if (lt.is_enabled()) {
2152 ResourceMark rm;
2153 LogStream ls(lt);
2154 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2155 if (has_last_Java_frame()) {
2156 frame f = last_frame();
2157 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2158 }
2159 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
2160 }
2161 _pending_async_exception = NULL;
2162 clear_has_async_exception();
2163 }
2164 }
2165
2166 if (check_unsafe_error &&
2167 condition == _async_unsafe_access_error && !has_pending_exception()) {
2168 condition = _no_async_condition; // done
2169 switch (thread_state()) {
2170 case _thread_in_vm: {
2171 JavaThread* THREAD = this;
2172 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2173 }
2174 case _thread_in_native: {
2175 ThreadInVMfromNative tiv(this);
2176 JavaThread* THREAD = this;
2177 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2178 }
2179 case _thread_in_Java: {
2180 ThreadInVMfromJava tiv(this);
2181 JavaThread* THREAD = this;
2182 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2183 }
2184 default:
2185 ShouldNotReachHere();
2186 }
2187 }
2188
2189 assert(condition == _no_async_condition || has_pending_exception() ||
2190 (!check_unsafe_error && condition == _async_unsafe_access_error),
2191 "must have handled the async condition, if no exception");
2192 }
2193
2194 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2195 //
2196 // Check for pending external suspend. Internal suspend requests do
2197 // not use handle_special_runtime_exit_condition().
2198 // If JNIEnv proxies are allowed, don't self-suspend if the target
2199 // thread is not the current thread. In older versions of jdbx, jdbx
2200 // threads could call into the VM with another thread's JNIEnv so we
2201 // can be here operating on behalf of a suspended thread (4432884).
2202 bool do_self_suspend = is_external_suspend_with_lock();
2203 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2204 //
2205 // Because thread is external suspended the safepoint code will count
2206 // thread as at a safepoint. This can be odd because we can be here
2207 // as _thread_in_Java which would normally transition to _thread_blocked
2208 // at a safepoint. We would like to mark the thread as _thread_blocked
2209 // before calling java_suspend_self like all other callers of it but
2210 // we must then observe proper safepoint protocol. (We can't leave
2211 // _thread_blocked with a safepoint in progress). However we can be
2212 // here as _thread_in_native_trans so we can't use a normal transition
2213 // constructor/destructor pair because they assert on that type of
2214 // transition. We could do something like:
2215 //
2216 // JavaThreadState state = thread_state();
2217 // set_thread_state(_thread_in_vm);
2218 // {
2219 // ThreadBlockInVM tbivm(this);
2220 // java_suspend_self()
2221 // }
2222 // set_thread_state(_thread_in_vm_trans);
2223 // if (safepoint) block;
2224 // set_thread_state(state);
2225 //
2226 // but that is pretty messy. Instead we just go with the way the
2227 // code has worked before and note that this is the only path to
2228 // java_suspend_self that doesn't put the thread in _thread_blocked
2229 // mode.
2230
2231 frame_anchor()->make_walkable(this);
2232 java_suspend_self();
2233
2234 // We might be here for reasons in addition to the self-suspend request
2235 // so check for other async requests.
2236 }
2237
2238 if (check_asyncs) {
2239 check_and_handle_async_exceptions();
2240 }
2241 #if INCLUDE_TRACE
2242 if (is_trace_suspend()) {
2243 TRACE_SUSPEND_THREAD(this);
2244 }
2245 #endif
2246 }
2247
2248 void JavaThread::send_thread_stop(oop java_throwable) {
2249 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2250 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2251 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2252
2253 // Do not throw asynchronous exceptions against the compiler thread
2254 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2255 if (!can_call_java()) return;
2256
2257 {
2258 // Actually throw the Throwable against the target Thread - however
2259 // only if there is no thread death exception installed already.
2260 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2261 // If the topmost frame is a runtime stub, then we are calling into
2262 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2263 // must deoptimize the caller before continuing, as the compiled exception handler table
2264 // may not be valid
2265 if (has_last_Java_frame()) {
2266 frame f = last_frame();
2267 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2268 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2269 RegisterMap reg_map(this, UseBiasedLocking);
2270 frame compiled_frame = f.sender(®_map);
2271 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2272 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2273 }
2274 }
2275 }
2276
2277 // Set async. pending exception in thread.
2278 set_pending_async_exception(java_throwable);
2279
2280 if (log_is_enabled(Info, exceptions)) {
2281 ResourceMark rm;
2282 log_info(exceptions)("Pending Async. exception installed of type: %s",
2283 InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2284 }
2285 // for AbortVMOnException flag
2286 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
2287 }
2288 }
2289
2290
2291 // Interrupt thread so it will wake up from a potential wait()
2292 Thread::interrupt(this);
2293 }
2294
2295 // External suspension mechanism.
2296 //
2297 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2298 // to any VM_locks and it is at a transition
2299 // Self-suspension will happen on the transition out of the vm.
2300 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2301 //
2302 // Guarantees on return:
2303 // + Target thread will not execute any new bytecode (that's why we need to
2304 // force a safepoint)
2305 // + Target thread will not enter any new monitors
2306 //
2307 void JavaThread::java_suspend() {
2308 ThreadsListHandle tlh;
2309 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) {
2310 return;
2311 }
2312
2313 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2314 if (!is_external_suspend()) {
2315 // a racing resume has cancelled us; bail out now
2316 return;
2317 }
2318
2319 // suspend is done
2320 uint32_t debug_bits = 0;
2321 // Warning: is_ext_suspend_completed() may temporarily drop the
2322 // SR_lock to allow the thread to reach a stable thread state if
2323 // it is currently in a transient thread state.
2324 if (is_ext_suspend_completed(false /* !called_by_wait */,
2325 SuspendRetryDelay, &debug_bits)) {
2326 return;
2327 }
2328 }
2329
2330 VM_ThreadSuspend vm_suspend;
2331 VMThread::execute(&vm_suspend);
2332 }
2333
2334 // Part II of external suspension.
2335 // A JavaThread self suspends when it detects a pending external suspend
2336 // request. This is usually on transitions. It is also done in places
2337 // where continuing to the next transition would surprise the caller,
2338 // e.g., monitor entry.
2339 //
2340 // Returns the number of times that the thread self-suspended.
2341 //
2342 // Note: DO NOT call java_suspend_self() when you just want to block current
2343 // thread. java_suspend_self() is the second stage of cooperative
2344 // suspension for external suspend requests and should only be used
2345 // to complete an external suspend request.
2346 //
2347 int JavaThread::java_suspend_self() {
2348 int ret = 0;
2349
2350 // we are in the process of exiting so don't suspend
2351 if (is_exiting()) {
2352 clear_external_suspend();
2353 return ret;
2354 }
2355
2356 assert(_anchor.walkable() ||
2357 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2358 "must have walkable stack");
2359
2360 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2361
2362 assert(!this->is_ext_suspended(),
2363 "a thread trying to self-suspend should not already be suspended");
2364
2365 if (this->is_suspend_equivalent()) {
2366 // If we are self-suspending as a result of the lifting of a
2367 // suspend equivalent condition, then the suspend_equivalent
2368 // flag is not cleared until we set the ext_suspended flag so
2369 // that wait_for_ext_suspend_completion() returns consistent
2370 // results.
2371 this->clear_suspend_equivalent();
2372 }
2373
2374 // A racing resume may have cancelled us before we grabbed SR_lock
2375 // above. Or another external suspend request could be waiting for us
2376 // by the time we return from SR_lock()->wait(). The thread
2377 // that requested the suspension may already be trying to walk our
2378 // stack and if we return now, we can change the stack out from under
2379 // it. This would be a "bad thing (TM)" and cause the stack walker
2380 // to crash. We stay self-suspended until there are no more pending
2381 // external suspend requests.
2382 while (is_external_suspend()) {
2383 ret++;
2384 this->set_ext_suspended();
2385
2386 // _ext_suspended flag is cleared by java_resume()
2387 while (is_ext_suspended()) {
2388 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2389 }
2390 }
2391
2392 return ret;
2393 }
2394
2395 #ifdef ASSERT
2396 // Verify the JavaThread has not yet been published in the Threads::list, and
2397 // hence doesn't need protection from concurrent access at this stage.
2398 void JavaThread::verify_not_published() {
2399 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
2400 // since an unpublished JavaThread doesn't participate in the
2401 // Thread-SMR protocol for keeping a ThreadsList alive.
2402 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
2403 }
2404 #endif
2405
2406 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2407 // progress or when _suspend_flags is non-zero.
2408 // Current thread needs to self-suspend if there is a suspend request and/or
2409 // block if a safepoint is in progress.
2410 // Async exception ISN'T checked.
2411 // Note only the ThreadInVMfromNative transition can call this function
2412 // directly and when thread state is _thread_in_native_trans
2413 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2414 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2415
2416 JavaThread *curJT = JavaThread::current();
2417 bool do_self_suspend = thread->is_external_suspend();
2418
2419 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2420
2421 // If JNIEnv proxies are allowed, don't self-suspend if the target
2422 // thread is not the current thread. In older versions of jdbx, jdbx
2423 // threads could call into the VM with another thread's JNIEnv so we
2424 // can be here operating on behalf of a suspended thread (4432884).
2425 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2426 JavaThreadState state = thread->thread_state();
2427
2428 // We mark this thread_blocked state as a suspend-equivalent so
2429 // that a caller to is_ext_suspend_completed() won't be confused.
2430 // The suspend-equivalent state is cleared by java_suspend_self().
2431 thread->set_suspend_equivalent();
2432
2433 // If the safepoint code sees the _thread_in_native_trans state, it will
2434 // wait until the thread changes to other thread state. There is no
2435 // guarantee on how soon we can obtain the SR_lock and complete the
2436 // self-suspend request. It would be a bad idea to let safepoint wait for
2437 // too long. Temporarily change the state to _thread_blocked to
2438 // let the VM thread know that this thread is ready for GC. The problem
2439 // of changing thread state is that safepoint could happen just after
2440 // java_suspend_self() returns after being resumed, and VM thread will
2441 // see the _thread_blocked state. We must check for safepoint
2442 // after restoring the state and make sure we won't leave while a safepoint
2443 // is in progress.
2444 thread->set_thread_state(_thread_blocked);
2445 thread->java_suspend_self();
2446 thread->set_thread_state(state);
2447
2448 InterfaceSupport::serialize_thread_state_with_handler(thread);
2449 }
2450
2451 SafepointMechanism::block_if_requested(curJT);
2452
2453 if (thread->is_deopt_suspend()) {
2454 thread->clear_deopt_suspend();
2455 RegisterMap map(thread, false);
2456 frame f = thread->last_frame();
2457 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2458 f = f.sender(&map);
2459 }
2460 if (f.id() == thread->must_deopt_id()) {
2461 thread->clear_must_deopt_id();
2462 f.deoptimize(thread);
2463 } else {
2464 fatal("missed deoptimization!");
2465 }
2466 }
2467 #if INCLUDE_TRACE
2468 if (thread->is_trace_suspend()) {
2469 TRACE_SUSPEND_THREAD(thread);
2470 }
2471 #endif
2472 }
2473
2474 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2475 // progress or when _suspend_flags is non-zero.
2476 // Current thread needs to self-suspend if there is a suspend request and/or
2477 // block if a safepoint is in progress.
2478 // Also check for pending async exception (not including unsafe access error).
2479 // Note only the native==>VM/Java barriers can call this function and when
2480 // thread state is _thread_in_native_trans.
2481 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2482 check_safepoint_and_suspend_for_native_trans(thread);
2483
2484 if (thread->has_async_exception()) {
2485 // We are in _thread_in_native_trans state, don't handle unsafe
2486 // access error since that may block.
2487 thread->check_and_handle_async_exceptions(false);
2488 }
2489 }
2490
2491 // This is a variant of the normal
2492 // check_special_condition_for_native_trans with slightly different
2493 // semantics for use by critical native wrappers. It does all the
2494 // normal checks but also performs the transition back into
2495 // thread_in_Java state. This is required so that critical natives
2496 // can potentially block and perform a GC if they are the last thread
2497 // exiting the GCLocker.
2498 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2499 check_special_condition_for_native_trans(thread);
2500
2501 // Finish the transition
2502 thread->set_thread_state(_thread_in_Java);
2503
2504 if (thread->do_critical_native_unlock()) {
2505 ThreadInVMfromJavaNoAsyncException tiv(thread);
2506 GCLocker::unlock_critical(thread);
2507 thread->clear_critical_native_unlock();
2508 }
2509 }
2510
2511 // We need to guarantee the Threads_lock here, since resumes are not
2512 // allowed during safepoint synchronization
2513 // Can only resume from an external suspension
2514 void JavaThread::java_resume() {
2515 assert_locked_or_safepoint(Threads_lock);
2516
2517 // Sanity check: thread is gone, has started exiting or the thread
2518 // was not externally suspended.
2519 ThreadsListHandle tlh;
2520 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) {
2521 return;
2522 }
2523
2524 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2525
2526 clear_external_suspend();
2527
2528 if (is_ext_suspended()) {
2529 clear_ext_suspended();
2530 SR_lock()->notify_all();
2531 }
2532 }
2533
2534 size_t JavaThread::_stack_red_zone_size = 0;
2535 size_t JavaThread::_stack_yellow_zone_size = 0;
2536 size_t JavaThread::_stack_reserved_zone_size = 0;
2537 size_t JavaThread::_stack_shadow_zone_size = 0;
2538
2539 void JavaThread::create_stack_guard_pages() {
2540 if (!os::uses_stack_guard_pages() ||
2541 _stack_guard_state != stack_guard_unused ||
2542 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) {
2543 log_info(os, thread)("Stack guard page creation for thread "
2544 UINTX_FORMAT " disabled", os::current_thread_id());
2545 return;
2546 }
2547 address low_addr = stack_end();
2548 size_t len = stack_guard_zone_size();
2549
2550 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
2551 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
2552
2553 int must_commit = os::must_commit_stack_guard_pages();
2554 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2555
2556 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
2557 log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
2558 return;
2559 }
2560
2561 if (os::guard_memory((char *) low_addr, len)) {
2562 _stack_guard_state = stack_guard_enabled;
2563 } else {
2564 log_warning(os, thread)("Attempt to protect stack guard pages failed ("
2565 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2566 if (os::uncommit_memory((char *) low_addr, len)) {
2567 log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
2568 }
2569 return;
2570 }
2571
2572 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
2573 PTR_FORMAT "-" PTR_FORMAT ".",
2574 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2575 }
2576
2577 void JavaThread::remove_stack_guard_pages() {
2578 assert(Thread::current() == this, "from different thread");
2579 if (_stack_guard_state == stack_guard_unused) return;
2580 address low_addr = stack_end();
2581 size_t len = stack_guard_zone_size();
2582
2583 if (os::must_commit_stack_guard_pages()) {
2584 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2585 _stack_guard_state = stack_guard_unused;
2586 } else {
2587 log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
2588 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2589 return;
2590 }
2591 } else {
2592 if (_stack_guard_state == stack_guard_unused) return;
2593 if (os::unguard_memory((char *) low_addr, len)) {
2594 _stack_guard_state = stack_guard_unused;
2595 } else {
2596 log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
2597 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
2598 return;
2599 }
2600 }
2601
2602 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
2603 PTR_FORMAT "-" PTR_FORMAT ".",
2604 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
2605 }
2606
2607 void JavaThread::enable_stack_reserved_zone() {
2608 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2609 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2610
2611 // The base notation is from the stack's point of view, growing downward.
2612 // We need to adjust it to work correctly with guard_memory()
2613 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2614
2615 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2616 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2617
2618 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2619 _stack_guard_state = stack_guard_enabled;
2620 } else {
2621 warning("Attempt to guard stack reserved zone failed.");
2622 }
2623 enable_register_stack_guard();
2624 }
2625
2626 void JavaThread::disable_stack_reserved_zone() {
2627 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2628 assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled");
2629
2630 // Simply return if called for a thread that does not use guard pages.
2631 if (_stack_guard_state == stack_guard_unused) return;
2632
2633 // The base notation is from the stack's point of view, growing downward.
2634 // We need to adjust it to work correctly with guard_memory()
2635 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2636
2637 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2638 _stack_guard_state = stack_guard_reserved_disabled;
2639 } else {
2640 warning("Attempt to unguard stack reserved zone failed.");
2641 }
2642 disable_register_stack_guard();
2643 }
2644
2645 void JavaThread::enable_stack_yellow_reserved_zone() {
2646 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2647 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2648
2649 // The base notation is from the stacks point of view, growing downward.
2650 // We need to adjust it to work correctly with guard_memory()
2651 address base = stack_red_zone_base();
2652
2653 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2654 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2655
2656 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
2657 _stack_guard_state = stack_guard_enabled;
2658 } else {
2659 warning("Attempt to guard stack yellow zone failed.");
2660 }
2661 enable_register_stack_guard();
2662 }
2663
2664 void JavaThread::disable_stack_yellow_reserved_zone() {
2665 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2666 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
2667
2668 // Simply return if called for a thread that does not use guard pages.
2669 if (_stack_guard_state == stack_guard_unused) return;
2670
2671 // The base notation is from the stacks point of view, growing downward.
2672 // We need to adjust it to work correctly with guard_memory()
2673 address base = stack_red_zone_base();
2674
2675 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
2676 _stack_guard_state = stack_guard_yellow_reserved_disabled;
2677 } else {
2678 warning("Attempt to unguard stack yellow zone failed.");
2679 }
2680 disable_register_stack_guard();
2681 }
2682
2683 void JavaThread::enable_stack_red_zone() {
2684 // The base notation is from the stacks point of view, growing downward.
2685 // We need to adjust it to work correctly with guard_memory()
2686 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2687 address base = stack_red_zone_base() - stack_red_zone_size();
2688
2689 guarantee(base < stack_base(), "Error calculating stack red zone");
2690 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2691
2692 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2693 warning("Attempt to guard stack red zone failed.");
2694 }
2695 }
2696
2697 void JavaThread::disable_stack_red_zone() {
2698 // The base notation is from the stacks point of view, growing downward.
2699 // We need to adjust it to work correctly with guard_memory()
2700 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2701 address base = stack_red_zone_base() - stack_red_zone_size();
2702 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2703 warning("Attempt to unguard stack red zone failed.");
2704 }
2705 }
2706
2707 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2708 // ignore is there is no stack
2709 if (!has_last_Java_frame()) return;
2710 // traverse the stack frames. Starts from top frame.
2711 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2712 frame* fr = fst.current();
2713 f(fr, fst.register_map());
2714 }
2715 }
2716
2717
2718 #ifndef PRODUCT
2719 // Deoptimization
2720 // Function for testing deoptimization
2721 void JavaThread::deoptimize() {
2722 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2723 StackFrameStream fst(this, UseBiasedLocking);
2724 bool deopt = false; // Dump stack only if a deopt actually happens.
2725 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2726 // Iterate over all frames in the thread and deoptimize
2727 for (; !fst.is_done(); fst.next()) {
2728 if (fst.current()->can_be_deoptimized()) {
2729
2730 if (only_at) {
2731 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2732 // consists of comma or carriage return separated numbers so
2733 // search for the current bci in that string.
2734 address pc = fst.current()->pc();
2735 nmethod* nm = (nmethod*) fst.current()->cb();
2736 ScopeDesc* sd = nm->scope_desc_at(pc);
2737 char buffer[8];
2738 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2739 size_t len = strlen(buffer);
2740 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2741 while (found != NULL) {
2742 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2743 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2744 // Check that the bci found is bracketed by terminators.
2745 break;
2746 }
2747 found = strstr(found + 1, buffer);
2748 }
2749 if (!found) {
2750 continue;
2751 }
2752 }
2753
2754 if (DebugDeoptimization && !deopt) {
2755 deopt = true; // One-time only print before deopt
2756 tty->print_cr("[BEFORE Deoptimization]");
2757 trace_frames();
2758 trace_stack();
2759 }
2760 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2761 }
2762 }
2763
2764 if (DebugDeoptimization && deopt) {
2765 tty->print_cr("[AFTER Deoptimization]");
2766 trace_frames();
2767 }
2768 }
2769
2770
2771 // Make zombies
2772 void JavaThread::make_zombies() {
2773 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2774 if (fst.current()->can_be_deoptimized()) {
2775 // it is a Java nmethod
2776 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2777 nm->make_not_entrant();
2778 }
2779 }
2780 }
2781 #endif // PRODUCT
2782
2783
2784 void JavaThread::deoptimized_wrt_marked_nmethods() {
2785 if (!has_last_Java_frame()) return;
2786 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2787 StackFrameStream fst(this, UseBiasedLocking);
2788 for (; !fst.is_done(); fst.next()) {
2789 if (fst.current()->should_be_deoptimized()) {
2790 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2791 }
2792 }
2793 }
2794
2795
2796 // If the caller is a NamedThread, then remember, in the current scope,
2797 // the given JavaThread in its _processed_thread field.
2798 class RememberProcessedThread: public StackObj {
2799 NamedThread* _cur_thr;
2800 public:
2801 RememberProcessedThread(JavaThread* jthr) {
2802 Thread* thread = Thread::current();
2803 if (thread->is_Named_thread()) {
2804 _cur_thr = (NamedThread *)thread;
2805 _cur_thr->set_processed_thread(jthr);
2806 } else {
2807 _cur_thr = NULL;
2808 }
2809 }
2810
2811 ~RememberProcessedThread() {
2812 if (_cur_thr) {
2813 _cur_thr->set_processed_thread(NULL);
2814 }
2815 }
2816 };
2817
2818 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2819 // Verify that the deferred card marks have been flushed.
2820 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2821
2822 // Traverse the GCHandles
2823 Thread::oops_do(f, cf);
2824
2825 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);)
2826
2827 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2828 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2829
2830 if (has_last_Java_frame()) {
2831 // Record JavaThread to GC thread
2832 RememberProcessedThread rpt(this);
2833
2834 // Traverse the privileged stack
2835 if (_privileged_stack_top != NULL) {
2836 _privileged_stack_top->oops_do(f);
2837 }
2838
2839 // traverse the registered growable array
2840 if (_array_for_gc != NULL) {
2841 for (int index = 0; index < _array_for_gc->length(); index++) {
2842 f->do_oop(_array_for_gc->adr_at(index));
2843 }
2844 }
2845
2846 // Traverse the monitor chunks
2847 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2848 chunk->oops_do(f);
2849 }
2850
2851 // Traverse the execution stack
2852 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2853 fst.current()->oops_do(f, cf, fst.register_map());
2854 }
2855 }
2856
2857 // callee_target is never live across a gc point so NULL it here should
2858 // it still contain a methdOop.
2859
2860 set_callee_target(NULL);
2861
2862 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2863 // If we have deferred set_locals there might be oops waiting to be
2864 // written
2865 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2866 if (list != NULL) {
2867 for (int i = 0; i < list->length(); i++) {
2868 list->at(i)->oops_do(f);
2869 }
2870 }
2871
2872 // Traverse instance variables at the end since the GC may be moving things
2873 // around using this function
2874 f->do_oop((oop*) &_threadObj);
2875 f->do_oop((oop*) &_vm_result);
2876 f->do_oop((oop*) &_exception_oop);
2877 f->do_oop((oop*) &_pending_async_exception);
2878
2879 if (jvmti_thread_state() != NULL) {
2880 jvmti_thread_state()->oops_do(f);
2881 }
2882 }
2883
2884 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2885 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2886 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2887
2888 if (has_last_Java_frame()) {
2889 // Traverse the execution stack
2890 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2891 fst.current()->nmethods_do(cf);
2892 }
2893 }
2894 }
2895
2896 void JavaThread::metadata_do(void f(Metadata*)) {
2897 if (has_last_Java_frame()) {
2898 // Traverse the execution stack to call f() on the methods in the stack
2899 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2900 fst.current()->metadata_do(f);
2901 }
2902 } else if (is_Compiler_thread()) {
2903 // need to walk ciMetadata in current compile tasks to keep alive.
2904 CompilerThread* ct = (CompilerThread*)this;
2905 if (ct->env() != NULL) {
2906 ct->env()->metadata_do(f);
2907 }
2908 CompileTask* task = ct->task();
2909 if (task != NULL) {
2910 task->metadata_do(f);
2911 }
2912 }
2913 }
2914
2915 // Printing
2916 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2917 switch (_thread_state) {
2918 case _thread_uninitialized: return "_thread_uninitialized";
2919 case _thread_new: return "_thread_new";
2920 case _thread_new_trans: return "_thread_new_trans";
2921 case _thread_in_native: return "_thread_in_native";
2922 case _thread_in_native_trans: return "_thread_in_native_trans";
2923 case _thread_in_vm: return "_thread_in_vm";
2924 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2925 case _thread_in_Java: return "_thread_in_Java";
2926 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2927 case _thread_blocked: return "_thread_blocked";
2928 case _thread_blocked_trans: return "_thread_blocked_trans";
2929 default: return "unknown thread state";
2930 }
2931 }
2932
2933 #ifndef PRODUCT
2934 void JavaThread::print_thread_state_on(outputStream *st) const {
2935 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2936 };
2937 void JavaThread::print_thread_state() const {
2938 print_thread_state_on(tty);
2939 }
2940 #endif // PRODUCT
2941
2942 // Called by Threads::print() for VM_PrintThreads operation
2943 void JavaThread::print_on(outputStream *st) const {
2944 st->print_raw("\"");
2945 st->print_raw(get_thread_name());
2946 st->print_raw("\" ");
2947 oop thread_oop = threadObj();
2948 if (thread_oop != NULL) {
2949 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
2950 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2951 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2952 }
2953 Thread::print_on(st);
2954 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2955 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2956 if (thread_oop != NULL) {
2957 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2958 }
2959 #ifndef PRODUCT
2960 print_thread_state_on(st);
2961 _safepoint_state->print_on(st);
2962 #endif // PRODUCT
2963 if (is_Compiler_thread()) {
2964 CompileTask *task = ((CompilerThread*)this)->task();
2965 if (task != NULL) {
2966 st->print(" Compiling: ");
2967 task->print(st, NULL, true, false);
2968 } else {
2969 st->print(" No compile task");
2970 }
2971 st->cr();
2972 }
2973 }
2974
2975 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
2976 st->print("%s", get_thread_name_string(buf, buflen));
2977 }
2978
2979 // Called by fatal error handler. The difference between this and
2980 // JavaThread::print() is that we can't grab lock or allocate memory.
2981 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2982 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2983 oop thread_obj = threadObj();
2984 if (thread_obj != NULL) {
2985 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2986 }
2987 st->print(" [");
2988 st->print("%s", _get_thread_state_name(_thread_state));
2989 if (osthread()) {
2990 st->print(", id=%d", osthread()->thread_id());
2991 }
2992 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2993 p2i(stack_end()), p2i(stack_base()));
2994 st->print("]");
2995
2996 if (_threads_hazard_ptr != NULL) {
2997 st->print(" _threads_hazard_ptr=" INTPTR_FORMAT, p2i(_threads_hazard_ptr));
2998 }
2999 if (_nested_threads_hazard_ptr != NULL) {
3000 print_nested_threads_hazard_ptrs_on(st);
3001 }
3002 return;
3003 }
3004
3005 // Verification
3006
3007 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
3008
3009 void JavaThread::verify() {
3010 // Verify oops in the thread.
3011 oops_do(&VerifyOopClosure::verify_oop, NULL);
3012
3013 // Verify the stack frames.
3014 frames_do(frame_verify);
3015 }
3016
3017 // CR 6300358 (sub-CR 2137150)
3018 // Most callers of this method assume that it can't return NULL but a
3019 // thread may not have a name whilst it is in the process of attaching to
3020 // the VM - see CR 6412693, and there are places where a JavaThread can be
3021 // seen prior to having it's threadObj set (eg JNI attaching threads and
3022 // if vm exit occurs during initialization). These cases can all be accounted
3023 // for such that this method never returns NULL.
3024 const char* JavaThread::get_thread_name() const {
3025 #ifdef ASSERT
3026 // early safepoints can hit while current thread does not yet have TLS
3027 if (!SafepointSynchronize::is_at_safepoint()) {
3028 Thread *cur = Thread::current();
3029 if (!(cur->is_Java_thread() && cur == this)) {
3030 // Current JavaThreads are allowed to get their own name without
3031 // the Threads_lock.
3032 assert_locked_or_safepoint(Threads_lock);
3033 }
3034 }
3035 #endif // ASSERT
3036 return get_thread_name_string();
3037 }
3038
3039 // Returns a non-NULL representation of this thread's name, or a suitable
3040 // descriptive string if there is no set name
3041 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
3042 const char* name_str;
3043 oop thread_obj = threadObj();
3044 if (thread_obj != NULL) {
3045 oop name = java_lang_Thread::name(thread_obj);
3046 if (name != NULL) {
3047 if (buf == NULL) {
3048 name_str = java_lang_String::as_utf8_string(name);
3049 } else {
3050 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
3051 }
3052 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
3053 name_str = "<no-name - thread is attaching>";
3054 } else {
3055 name_str = Thread::name();
3056 }
3057 } else {
3058 name_str = Thread::name();
3059 }
3060 assert(name_str != NULL, "unexpected NULL thread name");
3061 return name_str;
3062 }
3063
3064
3065 const char* JavaThread::get_threadgroup_name() const {
3066 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3067 oop thread_obj = threadObj();
3068 if (thread_obj != NULL) {
3069 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3070 if (thread_group != NULL) {
3071 // ThreadGroup.name can be null
3072 return java_lang_ThreadGroup::name(thread_group);
3073 }
3074 }
3075 return NULL;
3076 }
3077
3078 const char* JavaThread::get_parent_name() const {
3079 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
3080 oop thread_obj = threadObj();
3081 if (thread_obj != NULL) {
3082 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3083 if (thread_group != NULL) {
3084 oop parent = java_lang_ThreadGroup::parent(thread_group);
3085 if (parent != NULL) {
3086 // ThreadGroup.name can be null
3087 return java_lang_ThreadGroup::name(parent);
3088 }
3089 }
3090 }
3091 return NULL;
3092 }
3093
3094 ThreadPriority JavaThread::java_priority() const {
3095 oop thr_oop = threadObj();
3096 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3097 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3098 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3099 return priority;
3100 }
3101
3102 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3103
3104 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3105 // Link Java Thread object <-> C++ Thread
3106
3107 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3108 // and put it into a new Handle. The Handle "thread_oop" can then
3109 // be used to pass the C++ thread object to other methods.
3110
3111 // Set the Java level thread object (jthread) field of the
3112 // new thread (a JavaThread *) to C++ thread object using the
3113 // "thread_oop" handle.
3114
3115 // Set the thread field (a JavaThread *) of the
3116 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3117
3118 Handle thread_oop(Thread::current(),
3119 JNIHandles::resolve_non_null(jni_thread));
3120 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3121 "must be initialized");
3122 set_threadObj(thread_oop());
3123 java_lang_Thread::set_thread(thread_oop(), this);
3124
3125 if (prio == NoPriority) {
3126 prio = java_lang_Thread::priority(thread_oop());
3127 assert(prio != NoPriority, "A valid priority should be present");
3128 }
3129
3130 // Push the Java priority down to the native thread; needs Threads_lock
3131 Thread::set_priority(this, prio);
3132
3133 // Add the new thread to the Threads list and set it in motion.
3134 // We must have threads lock in order to call Threads::add.
3135 // It is crucial that we do not block before the thread is
3136 // added to the Threads list for if a GC happens, then the java_thread oop
3137 // will not be visited by GC.
3138 Threads::add(this);
3139 }
3140
3141 oop JavaThread::current_park_blocker() {
3142 // Support for JSR-166 locks
3143 oop thread_oop = threadObj();
3144 if (thread_oop != NULL &&
3145 JDK_Version::current().supports_thread_park_blocker()) {
3146 return java_lang_Thread::park_blocker(thread_oop);
3147 }
3148 return NULL;
3149 }
3150
3151
3152 void JavaThread::print_stack_on(outputStream* st) {
3153 if (!has_last_Java_frame()) return;
3154 ResourceMark rm;
3155 HandleMark hm;
3156
3157 RegisterMap reg_map(this);
3158 vframe* start_vf = last_java_vframe(®_map);
3159 int count = 0;
3160 for (vframe* f = start_vf; f != NULL; f = f->sender()) {
3161 if (f->is_java_frame()) {
3162 javaVFrame* jvf = javaVFrame::cast(f);
3163 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3164
3165 // Print out lock information
3166 if (JavaMonitorsInStackTrace) {
3167 jvf->print_lock_info_on(st, count);
3168 }
3169 } else {
3170 // Ignore non-Java frames
3171 }
3172
3173 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
3174 count++;
3175 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
3176 }
3177 }
3178
3179
3180 // JVMTI PopFrame support
3181 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3182 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3183 if (in_bytes(size_in_bytes) != 0) {
3184 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3185 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3186 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3187 }
3188 }
3189
3190 void* JavaThread::popframe_preserved_args() {
3191 return _popframe_preserved_args;
3192 }
3193
3194 ByteSize JavaThread::popframe_preserved_args_size() {
3195 return in_ByteSize(_popframe_preserved_args_size);
3196 }
3197
3198 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3199 int sz = in_bytes(popframe_preserved_args_size());
3200 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3201 return in_WordSize(sz / wordSize);
3202 }
3203
3204 void JavaThread::popframe_free_preserved_args() {
3205 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3206 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3207 _popframe_preserved_args = NULL;
3208 _popframe_preserved_args_size = 0;
3209 }
3210
3211 #ifndef PRODUCT
3212
3213 void JavaThread::trace_frames() {
3214 tty->print_cr("[Describe stack]");
3215 int frame_no = 1;
3216 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3217 tty->print(" %d. ", frame_no++);
3218 fst.current()->print_value_on(tty, this);
3219 tty->cr();
3220 }
3221 }
3222
3223 class PrintAndVerifyOopClosure: public OopClosure {
3224 protected:
3225 template <class T> inline void do_oop_work(T* p) {
3226 oop obj = RawAccess<>::oop_load(p);
3227 if (obj == NULL) return;
3228 tty->print(INTPTR_FORMAT ": ", p2i(p));
3229 if (oopDesc::is_oop_or_null(obj)) {
3230 if (obj->is_objArray()) {
3231 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3232 } else {
3233 obj->print();
3234 }
3235 } else {
3236 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3237 }
3238 tty->cr();
3239 }
3240 public:
3241 virtual void do_oop(oop* p) { do_oop_work(p); }
3242 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3243 };
3244
3245
3246 static void oops_print(frame* f, const RegisterMap *map) {
3247 PrintAndVerifyOopClosure print;
3248 f->print_value();
3249 f->oops_do(&print, NULL, (RegisterMap*)map);
3250 }
3251
3252 // Print our all the locations that contain oops and whether they are
3253 // valid or not. This useful when trying to find the oldest frame
3254 // where an oop has gone bad since the frame walk is from youngest to
3255 // oldest.
3256 void JavaThread::trace_oops() {
3257 tty->print_cr("[Trace oops]");
3258 frames_do(oops_print);
3259 }
3260
3261
3262 #ifdef ASSERT
3263 // Print or validate the layout of stack frames
3264 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3265 ResourceMark rm;
3266 PRESERVE_EXCEPTION_MARK;
3267 FrameValues values;
3268 int frame_no = 0;
3269 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3270 fst.current()->describe(values, ++frame_no);
3271 if (depth == frame_no) break;
3272 }
3273 if (validate_only) {
3274 values.validate();
3275 } else {
3276 tty->print_cr("[Describe stack layout]");
3277 values.print(this);
3278 }
3279 }
3280 #endif
3281
3282 void JavaThread::trace_stack_from(vframe* start_vf) {
3283 ResourceMark rm;
3284 int vframe_no = 1;
3285 for (vframe* f = start_vf; f; f = f->sender()) {
3286 if (f->is_java_frame()) {
3287 javaVFrame::cast(f)->print_activation(vframe_no++);
3288 } else {
3289 f->print();
3290 }
3291 if (vframe_no > StackPrintLimit) {
3292 tty->print_cr("...<more frames>...");
3293 return;
3294 }
3295 }
3296 }
3297
3298
3299 void JavaThread::trace_stack() {
3300 if (!has_last_Java_frame()) return;
3301 ResourceMark rm;
3302 HandleMark hm;
3303 RegisterMap reg_map(this);
3304 trace_stack_from(last_java_vframe(®_map));
3305 }
3306
3307
3308 #endif // PRODUCT
3309
3310
3311 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3312 assert(reg_map != NULL, "a map must be given");
3313 frame f = last_frame();
3314 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3315 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3316 }
3317 return NULL;
3318 }
3319
3320
3321 Klass* JavaThread::security_get_caller_class(int depth) {
3322 vframeStream vfst(this);
3323 vfst.security_get_caller_frame(depth);
3324 if (!vfst.at_end()) {
3325 return vfst.method()->method_holder();
3326 }
3327 return NULL;
3328 }
3329
3330 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3331 assert(thread->is_Compiler_thread(), "must be compiler thread");
3332 CompileBroker::compiler_thread_loop();
3333 }
3334
3335 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3336 NMethodSweeper::sweeper_loop();
3337 }
3338
3339 // Create a CompilerThread
3340 CompilerThread::CompilerThread(CompileQueue* queue,
3341 CompilerCounters* counters)
3342 : JavaThread(&compiler_thread_entry) {
3343 _env = NULL;
3344 _log = NULL;
3345 _task = NULL;
3346 _queue = queue;
3347 _counters = counters;
3348 _buffer_blob = NULL;
3349 _compiler = NULL;
3350
3351 // Compiler uses resource area for compilation, let's bias it to mtCompiler
3352 resource_area()->bias_to(mtCompiler);
3353
3354 #ifndef PRODUCT
3355 _ideal_graph_printer = NULL;
3356 #endif
3357 }
3358
3359 bool CompilerThread::can_call_java() const {
3360 return _compiler != NULL && _compiler->is_jvmci();
3361 }
3362
3363 // Create sweeper thread
3364 CodeCacheSweeperThread::CodeCacheSweeperThread()
3365 : JavaThread(&sweeper_thread_entry) {
3366 _scanned_compiled_method = NULL;
3367 }
3368
3369 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3370 JavaThread::oops_do(f, cf);
3371 if (_scanned_compiled_method != NULL && cf != NULL) {
3372 // Safepoints can occur when the sweeper is scanning an nmethod so
3373 // process it here to make sure it isn't unloaded in the middle of
3374 // a scan.
3375 cf->do_code_blob(_scanned_compiled_method);
3376 }
3377 }
3378
3379 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
3380 JavaThread::nmethods_do(cf);
3381 if (_scanned_compiled_method != NULL && cf != NULL) {
3382 // Safepoints can occur when the sweeper is scanning an nmethod so
3383 // process it here to make sure it isn't unloaded in the middle of
3384 // a scan.
3385 cf->do_code_blob(_scanned_compiled_method);
3386 }
3387 }
3388
3389
3390 // ======= Threads ========
3391
3392 // The Threads class links together all active threads, and provides
3393 // operations over all threads. It is protected by the Threads_lock,
3394 // which is also used in other global contexts like safepointing.
3395 // ThreadsListHandles are used to safely perform operations on one
3396 // or more threads without the risk of the thread exiting during the
3397 // operation.
3398 //
3399 // Note: The Threads_lock is currently more widely used than we
3400 // would like. We are actively migrating Threads_lock uses to other
3401 // mechanisms in order to reduce Threads_lock contention.
3402
3403 JavaThread* Threads::_thread_list = NULL;
3404 int Threads::_number_of_threads = 0;
3405 int Threads::_number_of_non_daemon_threads = 0;
3406 int Threads::_return_code = 0;
3407 int Threads::_thread_claim_parity = 0;
3408 size_t JavaThread::_stack_size_at_create = 0;
3409
3410 #ifdef ASSERT
3411 bool Threads::_vm_complete = false;
3412 #endif
3413
3414 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) {
3415 Prefetch::read((void*)addr, prefetch_interval);
3416 return *addr;
3417 }
3418
3419 // Possibly the ugliest for loop the world has seen. C++ does not allow
3420 // multiple types in the declaration section of the for loop. In this case
3421 // we are only dealing with pointers and hence can cast them. It looks ugly
3422 // but macros are ugly and therefore it's fine to make things absurdly ugly.
3423 #define DO_JAVA_THREADS(LIST, X) \
3424 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \
3425 *MACRO_list = (JavaThread*)(LIST), \
3426 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \
3427 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \
3428 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \
3429 MACRO_current_p != MACRO_end; \
3430 MACRO_current_p++, \
3431 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval))
3432
3433 // All JavaThreads
3434 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X)
3435
3436 // All non-JavaThreads (i.e., every non-JavaThread in the system).
3437 void Threads::non_java_threads_do(ThreadClosure* tc) {
3438 // Someday we could have a table or list of all non-JavaThreads.
3439 // For now, just manually iterate through them.
3440 tc->do_thread(VMThread::vm_thread());
3441 Universe::heap()->gc_threads_do(tc);
3442 WatcherThread *wt = WatcherThread::watcher_thread();
3443 // Strictly speaking, the following NULL check isn't sufficient to make sure
3444 // the data for WatcherThread is still valid upon being examined. However,
3445 // considering that WatchThread terminates when the VM is on the way to
3446 // exit at safepoint, the chance of the above is extremely small. The right
3447 // way to prevent termination of WatcherThread would be to acquire
3448 // Terminator_lock, but we can't do that without violating the lock rank
3449 // checking in some cases.
3450 if (wt != NULL) {
3451 tc->do_thread(wt);
3452 }
3453
3454 #if INCLUDE_TRACE
3455 Thread* sampler_thread = TracingExport::get_sampler_thread();
3456 if (sampler_thread != NULL) {
3457 tc->do_thread(sampler_thread);
3458 }
3459 #endif
3460
3461 // If CompilerThreads ever become non-JavaThreads, add them here
3462 }
3463
3464 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system).
3465 void Threads::threads_do(ThreadClosure* tc) {
3466 assert_locked_or_safepoint(Threads_lock);
3467 // ALL_JAVA_THREADS iterates through all JavaThreads.
3468 ALL_JAVA_THREADS(p) {
3469 tc->do_thread(p);
3470 }
3471 non_java_threads_do(tc);
3472 }
3473
3474 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) {
3475 int cp = Threads::thread_claim_parity();
3476 ALL_JAVA_THREADS(p) {
3477 if (p->claim_oops_do(is_par, cp)) {
3478 tc->do_thread(p);
3479 }
3480 }
3481 VMThread* vmt = VMThread::vm_thread();
3482 if (vmt->claim_oops_do(is_par, cp)) {
3483 tc->do_thread(vmt);
3484 }
3485 }
3486
3487 // The system initialization in the library has three phases.
3488 //
3489 // Phase 1: java.lang.System class initialization
3490 // java.lang.System is a primordial class loaded and initialized
3491 // by the VM early during startup. java.lang.System.<clinit>
3492 // only does registerNatives and keeps the rest of the class
3493 // initialization work later until thread initialization completes.
3494 //
3495 // System.initPhase1 initializes the system properties, the static
3496 // fields in, out, and err. Set up java signal handlers, OS-specific
3497 // system settings, and thread group of the main thread.
3498 static void call_initPhase1(TRAPS) {
3499 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3500 JavaValue result(T_VOID);
3501 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
3502 vmSymbols::void_method_signature(), CHECK);
3503 }
3504
3505 // Phase 2. Module system initialization
3506 // This will initialize the module system. Only java.base classes
3507 // can be loaded until phase 2 completes.
3508 //
3509 // Call System.initPhase2 after the compiler initialization and jsr292
3510 // classes get initialized because module initialization runs a lot of java
3511 // code, that for performance reasons, should be compiled. Also, this will
3512 // enable the startup code to use lambda and other language features in this
3513 // phase and onward.
3514 //
3515 // After phase 2, The VM will begin search classes from -Xbootclasspath/a.
3516 static void call_initPhase2(TRAPS) {
3517 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
3518
3519 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3520
3521 JavaValue result(T_INT);
3522 JavaCallArguments args;
3523 args.push_int(DisplayVMOutputToStderr);
3524 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
3525 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
3526 vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
3527 if (result.get_jint() != JNI_OK) {
3528 vm_exit_during_initialization(); // no message or exception
3529 }
3530
3531 universe_post_module_init();
3532 }
3533
3534 // Phase 3. final setup - set security manager, system class loader and TCCL
3535 //
3536 // This will instantiate and set the security manager, set the system class
3537 // loader as well as the thread context class loader. The security manager
3538 // and system class loader may be a custom class loaded from -Xbootclasspath/a,
3539 // other modules or the application's classpath.
3540 static void call_initPhase3(TRAPS) {
3541 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
3542 JavaValue result(T_VOID);
3543 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
3544 vmSymbols::void_method_signature(), CHECK);
3545 }
3546
3547 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3548 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
3549
3550 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3551 create_vm_init_libraries();
3552 }
3553
3554 initialize_class(vmSymbols::java_lang_String(), CHECK);
3555
3556 // Inject CompactStrings value after the static initializers for String ran.
3557 java_lang_String::set_compact_strings(CompactStrings);
3558
3559 // Initialize java_lang.System (needed before creating the thread)
3560 initialize_class(vmSymbols::java_lang_System(), CHECK);
3561 // The VM creates & returns objects of this class. Make sure it's initialized.
3562 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3563 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3564 Handle thread_group = create_initial_thread_group(CHECK);
3565 Universe::set_main_thread_group(thread_group());
3566 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3567 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3568 main_thread->set_threadObj(thread_object);
3569 // Set thread status to running since main thread has
3570 // been started and running.
3571 java_lang_Thread::set_thread_status(thread_object,
3572 java_lang_Thread::RUNNABLE);
3573
3574 // The VM creates objects of this class.
3575 initialize_class(vmSymbols::java_lang_Module(), CHECK);
3576
3577 // The VM preresolves methods to these classes. Make sure that they get initialized
3578 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3579 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3580
3581 // Phase 1 of the system initialization in the library, java.lang.System class initialization
3582 call_initPhase1(CHECK);
3583
3584 // get the Java runtime name after java.lang.System is initialized
3585 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3586 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3587
3588 // an instance of OutOfMemory exception has been allocated earlier
3589 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3590 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3591 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3592 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3593 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3594 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3595 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3596 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3597 }
3598
3599 void Threads::initialize_jsr292_core_classes(TRAPS) {
3600 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
3601
3602 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3603 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
3604 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3605 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3606 }
3607
3608 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3609 extern void JDK_Version_init();
3610
3611 // Preinitialize version info.
3612 VM_Version::early_initialize();
3613
3614 // Check version
3615 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3616
3617 // Initialize library-based TLS
3618 ThreadLocalStorage::init();
3619
3620 // Initialize the output stream module
3621 ostream_init();
3622
3623 // Process java launcher properties.
3624 Arguments::process_sun_java_launcher_properties(args);
3625
3626 // Initialize the os module
3627 os::init();
3628
3629 // Record VM creation timing statistics
3630 TraceVmCreationTime create_vm_timer;
3631 create_vm_timer.start();
3632
3633 // Initialize system properties.
3634 Arguments::init_system_properties();
3635
3636 // So that JDK version can be used as a discriminator when parsing arguments
3637 JDK_Version_init();
3638
3639 // Update/Initialize System properties after JDK version number is known
3640 Arguments::init_version_specific_system_properties();
3641
3642 // Make sure to initialize log configuration *before* parsing arguments
3643 LogConfiguration::initialize(create_vm_timer.begin_time());
3644
3645 // Parse arguments
3646 // Note: this internally calls os::init_container_support()
3647 jint parse_result = Arguments::parse(args);
3648 if (parse_result != JNI_OK) return parse_result;
3649
3650 os::init_before_ergo();
3651
3652 jint ergo_result = Arguments::apply_ergo();
3653 if (ergo_result != JNI_OK) return ergo_result;
3654
3655 // Final check of all ranges after ergonomics which may change values.
3656 if (!CommandLineFlagRangeList::check_ranges()) {
3657 return JNI_EINVAL;
3658 }
3659
3660 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3661 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3662 if (!constraint_result) {
3663 return JNI_EINVAL;
3664 }
3665
3666 CommandLineFlagWriteableList::mark_startup();
3667
3668 if (PauseAtStartup) {
3669 os::pause();
3670 }
3671
3672 HOTSPOT_VM_INIT_BEGIN();
3673
3674 // Timing (must come after argument parsing)
3675 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
3676
3677 // Initialize the os module after parsing the args
3678 jint os_init_2_result = os::init_2();
3679 if (os_init_2_result != JNI_OK) return os_init_2_result;
3680
3681 SafepointMechanism::initialize();
3682
3683 jint adjust_after_os_result = Arguments::adjust_after_os();
3684 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3685
3686 // Initialize output stream logging
3687 ostream_init_log();
3688
3689 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3690 // Must be before create_vm_init_agents()
3691 if (Arguments::init_libraries_at_startup()) {
3692 convert_vm_init_libraries_to_agents();
3693 }
3694
3695 // Launch -agentlib/-agentpath and converted -Xrun agents
3696 if (Arguments::init_agents_at_startup()) {
3697 create_vm_init_agents();
3698 }
3699
3700 // Initialize Threads state
3701 _thread_list = NULL;
3702 _number_of_threads = 0;
3703 _number_of_non_daemon_threads = 0;
3704
3705 // Initialize global data structures and create system classes in heap
3706 vm_init_globals();
3707
3708 #if INCLUDE_JVMCI
3709 if (JVMCICounterSize > 0) {
3710 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3711 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3712 } else {
3713 JavaThread::_jvmci_old_thread_counters = NULL;
3714 }
3715 #endif // INCLUDE_JVMCI
3716
3717 // Attach the main thread to this os thread
3718 JavaThread* main_thread = new JavaThread();
3719 main_thread->set_thread_state(_thread_in_vm);
3720 main_thread->initialize_thread_current();
3721 // must do this before set_active_handles
3722 main_thread->record_stack_base_and_size();
3723 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3724
3725 if (!main_thread->set_as_starting_thread()) {
3726 vm_shutdown_during_initialization(
3727 "Failed necessary internal allocation. Out of swap space");
3728 main_thread->smr_delete();
3729 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3730 return JNI_ENOMEM;
3731 }
3732
3733 // Enable guard page *after* os::create_main_thread(), otherwise it would
3734 // crash Linux VM, see notes in os_linux.cpp.
3735 main_thread->create_stack_guard_pages();
3736
3737 // Initialize Java-Level synchronization subsystem
3738 ObjectMonitor::Initialize();
3739
3740 // Initialize global modules
3741 jint status = init_globals();
3742 if (status != JNI_OK) {
3743 main_thread->smr_delete();
3744 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3745 return status;
3746 }
3747
3748 if (TRACE_INITIALIZE() != JNI_OK) {
3749 vm_exit_during_initialization("Failed to initialize tracing backend");
3750 }
3751
3752 // Should be done after the heap is fully created
3753 main_thread->cache_global_variables();
3754
3755 HandleMark hm;
3756
3757 { MutexLocker mu(Threads_lock);
3758 Threads::add(main_thread);
3759 }
3760
3761 // Any JVMTI raw monitors entered in onload will transition into
3762 // real raw monitor. VM is setup enough here for raw monitor enter.
3763 JvmtiExport::transition_pending_onload_raw_monitors();
3764
3765 // Create the VMThread
3766 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
3767
3768 VMThread::create();
3769 Thread* vmthread = VMThread::vm_thread();
3770
3771 if (!os::create_thread(vmthread, os::vm_thread)) {
3772 vm_exit_during_initialization("Cannot create VM thread. "
3773 "Out of system resources.");
3774 }
3775
3776 // Wait for the VM thread to become ready, and VMThread::run to initialize
3777 // Monitors can have spurious returns, must always check another state flag
3778 {
3779 MutexLocker ml(Notify_lock);
3780 os::start_thread(vmthread);
3781 while (vmthread->active_handles() == NULL) {
3782 Notify_lock->wait();
3783 }
3784 }
3785 }
3786
3787 assert(Universe::is_fully_initialized(), "not initialized");
3788 if (VerifyDuringStartup) {
3789 // Make sure we're starting with a clean slate.
3790 VM_Verify verify_op;
3791 VMThread::execute(&verify_op);
3792 }
3793
3794 Thread* THREAD = Thread::current();
3795
3796 // Always call even when there are not JVMTI environments yet, since environments
3797 // may be attached late and JVMTI must track phases of VM execution
3798 JvmtiExport::enter_early_start_phase();
3799
3800 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3801 JvmtiExport::post_early_vm_start();
3802
3803 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3804
3805 // We need this for ClassDataSharing - the initial vm.info property is set
3806 // with the default value of CDS "sharing" which may be reset through
3807 // command line options.
3808 reset_vm_info_property(CHECK_JNI_ERR);
3809
3810 quicken_jni_functions();
3811
3812 // No more stub generation allowed after that point.
3813 StubCodeDesc::freeze();
3814
3815 // Set flag that basic initialization has completed. Used by exceptions and various
3816 // debug stuff, that does not work until all basic classes have been initialized.
3817 set_init_completed();
3818
3819 LogConfiguration::post_initialize();
3820 Metaspace::post_initialize();
3821
3822 HOTSPOT_VM_INIT_END();
3823
3824 // record VM initialization completion time
3825 #if INCLUDE_MANAGEMENT
3826 Management::record_vm_init_completed();
3827 #endif // INCLUDE_MANAGEMENT
3828
3829 // Signal Dispatcher needs to be started before VMInit event is posted
3830 os::signal_init(CHECK_JNI_ERR);
3831
3832 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3833 if (!DisableAttachMechanism) {
3834 AttachListener::vm_start();
3835 if (StartAttachListener || AttachListener::init_at_startup()) {
3836 AttachListener::init();
3837 }
3838 }
3839
3840 // Launch -Xrun agents
3841 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3842 // back-end can launch with -Xdebug -Xrunjdwp.
3843 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3844 create_vm_init_libraries();
3845 }
3846
3847 if (CleanChunkPoolAsync) {
3848 Chunk::start_chunk_pool_cleaner_task();
3849 }
3850
3851 // initialize compiler(s)
3852 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
3853 #if INCLUDE_JVMCI
3854 bool force_JVMCI_intialization = false;
3855 if (EnableJVMCI) {
3856 // Initialize JVMCI eagerly when it is explicitly requested.
3857 // Or when JVMCIPrintProperties is enabled.
3858 // The JVMCI Java initialization code will read this flag and
3859 // do the printing if it's set.
3860 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties;
3861
3862 if (!force_JVMCI_intialization) {
3863 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
3864 // compilations via JVMCI will not actually block until JVMCI is initialized.
3865 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
3866 }
3867 }
3868 #endif
3869 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR);
3870 // Postpone completion of compiler initialization to after JVMCI
3871 // is initialized to avoid timeouts of blocking compilations.
3872 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) {
3873 CompileBroker::compilation_init_phase2();
3874 }
3875 #endif
3876
3877 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3878 // It is done after compilers are initialized, because otherwise compilations of
3879 // signature polymorphic MH intrinsics can be missed
3880 // (see SystemDictionary::find_method_handle_intrinsic).
3881 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3882
3883 // This will initialize the module system. Only java.base classes can be
3884 // loaded until phase 2 completes
3885 call_initPhase2(CHECK_JNI_ERR);
3886
3887 // Always call even when there are not JVMTI environments yet, since environments
3888 // may be attached late and JVMTI must track phases of VM execution
3889 JvmtiExport::enter_start_phase();
3890
3891 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3892 JvmtiExport::post_vm_start();
3893
3894 // Final system initialization including security manager and system class loader
3895 call_initPhase3(CHECK_JNI_ERR);
3896
3897 // cache the system and platform class loaders
3898 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR);
3899
3900 #if INCLUDE_JVMCI
3901 if (force_JVMCI_intialization) {
3902 JVMCIRuntime::force_initialization(CHECK_JNI_ERR);
3903 CompileBroker::compilation_init_phase2();
3904 }
3905 #endif
3906
3907 // Always call even when there are not JVMTI environments yet, since environments
3908 // may be attached late and JVMTI must track phases of VM execution
3909 JvmtiExport::enter_live_phase();
3910
3911 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3912 JvmtiExport::post_vm_initialized();
3913
3914 if (TRACE_START() != JNI_OK) {
3915 vm_exit_during_initialization("Failed to start tracing backend.");
3916 }
3917
3918 #if INCLUDE_MANAGEMENT
3919 Management::initialize(THREAD);
3920
3921 if (HAS_PENDING_EXCEPTION) {
3922 // management agent fails to start possibly due to
3923 // configuration problem and is responsible for printing
3924 // stack trace if appropriate. Simply exit VM.
3925 vm_exit(1);
3926 }
3927 #endif // INCLUDE_MANAGEMENT
3928
3929 if (MemProfiling) MemProfiler::engage();
3930 StatSampler::engage();
3931 if (CheckJNICalls) JniPeriodicChecker::engage();
3932
3933 BiasedLocking::init();
3934
3935 #if INCLUDE_RTM_OPT
3936 RTMLockingCounters::init();
3937 #endif
3938
3939 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3940 call_postVMInitHook(THREAD);
3941 // The Java side of PostVMInitHook.run must deal with all
3942 // exceptions and provide means of diagnosis.
3943 if (HAS_PENDING_EXCEPTION) {
3944 CLEAR_PENDING_EXCEPTION;
3945 }
3946 }
3947
3948 {
3949 MutexLocker ml(PeriodicTask_lock);
3950 // Make sure the WatcherThread can be started by WatcherThread::start()
3951 // or by dynamic enrollment.
3952 WatcherThread::make_startable();
3953 // Start up the WatcherThread if there are any periodic tasks
3954 // NOTE: All PeriodicTasks should be registered by now. If they
3955 // aren't, late joiners might appear to start slowly (we might
3956 // take a while to process their first tick).
3957 if (PeriodicTask::num_tasks() > 0) {
3958 WatcherThread::start();
3959 }
3960 }
3961
3962 create_vm_timer.end();
3963 #ifdef ASSERT
3964 _vm_complete = true;
3965 #endif
3966
3967 if (DumpSharedSpaces) {
3968 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3969 ShouldNotReachHere();
3970 }
3971
3972 return JNI_OK;
3973 }
3974
3975 // type for the Agent_OnLoad and JVM_OnLoad entry points
3976 extern "C" {
3977 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3978 }
3979 // Find a command line agent library and return its entry point for
3980 // -agentlib: -agentpath: -Xrun
3981 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3982 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3983 const char *on_load_symbols[],
3984 size_t num_symbol_entries) {
3985 OnLoadEntry_t on_load_entry = NULL;
3986 void *library = NULL;
3987
3988 if (!agent->valid()) {
3989 char buffer[JVM_MAXPATHLEN];
3990 char ebuf[1024] = "";
3991 const char *name = agent->name();
3992 const char *msg = "Could not find agent library ";
3993
3994 // First check to see if agent is statically linked into executable
3995 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3996 library = agent->os_lib();
3997 } else if (agent->is_absolute_path()) {
3998 library = os::dll_load(name, ebuf, sizeof ebuf);
3999 if (library == NULL) {
4000 const char *sub_msg = " in absolute path, with error: ";
4001 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
4002 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4003 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4004 // If we can't find the agent, exit.
4005 vm_exit_during_initialization(buf, NULL);
4006 FREE_C_HEAP_ARRAY(char, buf);
4007 }
4008 } else {
4009 // Try to load the agent from the standard dll directory
4010 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
4011 name)) {
4012 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4013 }
4014 if (library == NULL) { // Try the library path directory.
4015 if (os::dll_build_name(buffer, sizeof(buffer), name)) {
4016 library = os::dll_load(buffer, ebuf, sizeof ebuf);
4017 }
4018 if (library == NULL) {
4019 const char *sub_msg = " on the library path, with error: ";
4020 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image.";
4021
4022 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) +
4023 strlen(ebuf) + strlen(sub_msg2) + 1;
4024 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
4025 if (!agent->is_instrument_lib()) {
4026 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
4027 } else {
4028 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2);
4029 }
4030 // If we can't find the agent, exit.
4031 vm_exit_during_initialization(buf, NULL);
4032 FREE_C_HEAP_ARRAY(char, buf);
4033 }
4034 }
4035 }
4036 agent->set_os_lib(library);
4037 agent->set_valid();
4038 }
4039
4040 // Find the OnLoad function.
4041 on_load_entry =
4042 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
4043 false,
4044 on_load_symbols,
4045 num_symbol_entries));
4046 return on_load_entry;
4047 }
4048
4049 // Find the JVM_OnLoad entry point
4050 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
4051 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
4052 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4053 }
4054
4055 // Find the Agent_OnLoad entry point
4056 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
4057 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
4058 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
4059 }
4060
4061 // For backwards compatibility with -Xrun
4062 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
4063 // treated like -agentpath:
4064 // Must be called before agent libraries are created
4065 void Threads::convert_vm_init_libraries_to_agents() {
4066 AgentLibrary* agent;
4067 AgentLibrary* next;
4068
4069 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
4070 next = agent->next(); // cache the next agent now as this agent may get moved off this list
4071 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4072
4073 // If there is an JVM_OnLoad function it will get called later,
4074 // otherwise see if there is an Agent_OnLoad
4075 if (on_load_entry == NULL) {
4076 on_load_entry = lookup_agent_on_load(agent);
4077 if (on_load_entry != NULL) {
4078 // switch it to the agent list -- so that Agent_OnLoad will be called,
4079 // JVM_OnLoad won't be attempted and Agent_OnUnload will
4080 Arguments::convert_library_to_agent(agent);
4081 } else {
4082 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
4083 }
4084 }
4085 }
4086 }
4087
4088 // Create agents for -agentlib: -agentpath: and converted -Xrun
4089 // Invokes Agent_OnLoad
4090 // Called very early -- before JavaThreads exist
4091 void Threads::create_vm_init_agents() {
4092 extern struct JavaVM_ main_vm;
4093 AgentLibrary* agent;
4094
4095 JvmtiExport::enter_onload_phase();
4096
4097 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4098 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
4099
4100 if (on_load_entry != NULL) {
4101 // Invoke the Agent_OnLoad function
4102 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4103 if (err != JNI_OK) {
4104 vm_exit_during_initialization("agent library failed to init", agent->name());
4105 }
4106 } else {
4107 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
4108 }
4109 }
4110 JvmtiExport::enter_primordial_phase();
4111 }
4112
4113 extern "C" {
4114 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
4115 }
4116
4117 void Threads::shutdown_vm_agents() {
4118 // Send any Agent_OnUnload notifications
4119 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
4120 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
4121 extern struct JavaVM_ main_vm;
4122 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
4123
4124 // Find the Agent_OnUnload function.
4125 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
4126 os::find_agent_function(agent,
4127 false,
4128 on_unload_symbols,
4129 num_symbol_entries));
4130
4131 // Invoke the Agent_OnUnload function
4132 if (unload_entry != NULL) {
4133 JavaThread* thread = JavaThread::current();
4134 ThreadToNativeFromVM ttn(thread);
4135 HandleMark hm(thread);
4136 (*unload_entry)(&main_vm);
4137 }
4138 }
4139 }
4140
4141 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
4142 // Invokes JVM_OnLoad
4143 void Threads::create_vm_init_libraries() {
4144 extern struct JavaVM_ main_vm;
4145 AgentLibrary* agent;
4146
4147 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
4148 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
4149
4150 if (on_load_entry != NULL) {
4151 // Invoke the JVM_OnLoad function
4152 JavaThread* thread = JavaThread::current();
4153 ThreadToNativeFromVM ttn(thread);
4154 HandleMark hm(thread);
4155 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
4156 if (err != JNI_OK) {
4157 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
4158 }
4159 } else {
4160 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
4161 }
4162 }
4163 }
4164
4165
4166 // Last thread running calls java.lang.Shutdown.shutdown()
4167 void JavaThread::invoke_shutdown_hooks() {
4168 HandleMark hm(this);
4169
4170 // We could get here with a pending exception, if so clear it now.
4171 if (this->has_pending_exception()) {
4172 this->clear_pending_exception();
4173 }
4174
4175 EXCEPTION_MARK;
4176 Klass* shutdown_klass =
4177 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
4178 THREAD);
4179 if (shutdown_klass != NULL) {
4180 // SystemDictionary::resolve_or_null will return null if there was
4181 // an exception. If we cannot load the Shutdown class, just don't
4182 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
4183 // won't be run. Note that if a shutdown hook was registered,
4184 // the Shutdown class would have already been loaded
4185 // (Runtime.addShutdownHook will load it).
4186 JavaValue result(T_VOID);
4187 JavaCalls::call_static(&result,
4188 shutdown_klass,
4189 vmSymbols::shutdown_method_name(),
4190 vmSymbols::void_method_signature(),
4191 THREAD);
4192 }
4193 CLEAR_PENDING_EXCEPTION;
4194 }
4195
4196 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
4197 // the program falls off the end of main(). Another VM exit path is through
4198 // vm_exit() when the program calls System.exit() to return a value or when
4199 // there is a serious error in VM. The two shutdown paths are not exactly
4200 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
4201 // and VM_Exit op at VM level.
4202 //
4203 // Shutdown sequence:
4204 // + Shutdown native memory tracking if it is on
4205 // + Wait until we are the last non-daemon thread to execute
4206 // <-- every thing is still working at this moment -->
4207 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
4208 // shutdown hooks
4209 // + Call before_exit(), prepare for VM exit
4210 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
4211 // currently the only user of this mechanism is File.deleteOnExit())
4212 // > stop StatSampler, watcher thread, CMS threads,
4213 // post thread end and vm death events to JVMTI,
4214 // stop signal thread
4215 // + Call JavaThread::exit(), it will:
4216 // > release JNI handle blocks, remove stack guard pages
4217 // > remove this thread from Threads list
4218 // <-- no more Java code from this thread after this point -->
4219 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4220 // the compiler threads at safepoint
4221 // <-- do not use anything that could get blocked by Safepoint -->
4222 // + Disable tracing at JNI/JVM barriers
4223 // + Set _vm_exited flag for threads that are still running native code
4224 // + Delete this thread
4225 // + Call exit_globals()
4226 // > deletes tty
4227 // > deletes PerfMemory resources
4228 // + Return to caller
4229
4230 bool Threads::destroy_vm() {
4231 JavaThread* thread = JavaThread::current();
4232
4233 #ifdef ASSERT
4234 _vm_complete = false;
4235 #endif
4236 // Wait until we are the last non-daemon thread to execute
4237 { MutexLocker nu(Threads_lock);
4238 while (Threads::number_of_non_daemon_threads() > 1)
4239 // This wait should make safepoint checks, wait without a timeout,
4240 // and wait as a suspend-equivalent condition.
4241 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4242 Mutex::_as_suspend_equivalent_flag);
4243 }
4244
4245 EventShutdown e;
4246 if (e.should_commit()) {
4247 e.set_reason("No remaining non-daemon Java threads");
4248 e.commit();
4249 }
4250
4251 // Hang forever on exit if we are reporting an error.
4252 if (ShowMessageBoxOnError && VMError::is_error_reported()) {
4253 os::infinite_sleep();
4254 }
4255 os::wait_for_keypress_at_exit();
4256
4257 // run Java level shutdown hooks
4258 thread->invoke_shutdown_hooks();
4259
4260 before_exit(thread);
4261
4262 thread->exit(true);
4263
4264 // Stop VM thread.
4265 {
4266 // 4945125 The vm thread comes to a safepoint during exit.
4267 // GC vm_operations can get caught at the safepoint, and the
4268 // heap is unparseable if they are caught. Grab the Heap_lock
4269 // to prevent this. The GC vm_operations will not be able to
4270 // queue until after the vm thread is dead. After this point,
4271 // we'll never emerge out of the safepoint before the VM exits.
4272
4273 MutexLocker ml(Heap_lock);
4274
4275 VMThread::wait_for_vm_thread_exit();
4276 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4277 VMThread::destroy();
4278 }
4279
4280 // Now, all Java threads are gone except daemon threads. Daemon threads
4281 // running Java code or in VM are stopped by the Safepoint. However,
4282 // daemon threads executing native code are still running. But they
4283 // will be stopped at native=>Java/VM barriers. Note that we can't
4284 // simply kill or suspend them, as it is inherently deadlock-prone.
4285
4286 VM_Exit::set_vm_exited();
4287
4288 // Clean up ideal graph printers after the VMThread has started
4289 // the final safepoint which will block all the Compiler threads.
4290 // Note that this Thread has already logically exited so the
4291 // clean_up() function's use of a JavaThreadIteratorWithHandle
4292 // would be a problem except set_vm_exited() has remembered the
4293 // shutdown thread which is granted a policy exception.
4294 #if defined(COMPILER2) && !defined(PRODUCT)
4295 IdealGraphPrinter::clean_up();
4296 #endif
4297
4298 notify_vm_shutdown();
4299
4300 // We are after VM_Exit::set_vm_exited() so we can't call
4301 // thread->smr_delete() or we will block on the Threads_lock.
4302 // Deleting the shutdown thread here is safe because another
4303 // JavaThread cannot have an active ThreadsListHandle for
4304 // this JavaThread.
4305 delete thread;
4306
4307 #if INCLUDE_JVMCI
4308 if (JVMCICounterSize > 0) {
4309 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4310 }
4311 #endif
4312
4313 // exit_globals() will delete tty
4314 exit_globals();
4315
4316 LogConfiguration::finalize();
4317
4318 return true;
4319 }
4320
4321
4322 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4323 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4324 return is_supported_jni_version(version);
4325 }
4326
4327
4328 jboolean Threads::is_supported_jni_version(jint version) {
4329 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4330 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4331 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4332 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4333 if (version == JNI_VERSION_9) return JNI_TRUE;
4334 if (version == JNI_VERSION_10) return JNI_TRUE;
4335 return JNI_FALSE;
4336 }
4337
4338
4339 void Threads::add(JavaThread* p, bool force_daemon) {
4340 // The threads lock must be owned at this point
4341 assert_locked_or_safepoint(Threads_lock);
4342
4343 BarrierSet::barrier_set()->on_thread_attach(p);
4344
4345 p->set_next(_thread_list);
4346 _thread_list = p;
4347
4348 // Once a JavaThread is added to the Threads list, smr_delete() has
4349 // to be used to delete it. Otherwise we can just delete it directly.
4350 p->set_on_thread_list();
4351
4352 _number_of_threads++;
4353 oop threadObj = p->threadObj();
4354 bool daemon = true;
4355 // Bootstrapping problem: threadObj can be null for initial
4356 // JavaThread (or for threads attached via JNI)
4357 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4358 _number_of_non_daemon_threads++;
4359 daemon = false;
4360 }
4361
4362 ThreadService::add_thread(p, daemon);
4363
4364 // Maintain fast thread list
4365 ThreadsSMRSupport::add_thread(p);
4366
4367 // Possible GC point.
4368 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4369 }
4370
4371 void Threads::remove(JavaThread* p) {
4372
4373 // Reclaim the objectmonitors from the omInUseList and omFreeList of the moribund thread.
4374 ObjectSynchronizer::omFlush(p);
4375
4376 // Extra scope needed for Thread_lock, so we can check
4377 // that we do not remove thread without safepoint code notice
4378 { MutexLocker ml(Threads_lock);
4379
4380 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present");
4381
4382 // Maintain fast thread list
4383 ThreadsSMRSupport::remove_thread(p);
4384
4385 JavaThread* current = _thread_list;
4386 JavaThread* prev = NULL;
4387
4388 while (current != p) {
4389 prev = current;
4390 current = current->next();
4391 }
4392
4393 if (prev) {
4394 prev->set_next(current->next());
4395 } else {
4396 _thread_list = p->next();
4397 }
4398
4399 _number_of_threads--;
4400 oop threadObj = p->threadObj();
4401 bool daemon = true;
4402 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4403 _number_of_non_daemon_threads--;
4404 daemon = false;
4405
4406 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4407 // on destroy_vm will wake up.
4408 if (number_of_non_daemon_threads() == 1) {
4409 Threads_lock->notify_all();
4410 }
4411 }
4412 ThreadService::remove_thread(p, daemon);
4413
4414 // Make sure that safepoint code disregard this thread. This is needed since
4415 // the thread might mess around with locks after this point. This can cause it
4416 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4417 // of this thread since it is removed from the queue.
4418 p->set_terminated_value();
4419 } // unlock Threads_lock
4420
4421 // Since Events::log uses a lock, we grab it outside the Threads_lock
4422 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4423 }
4424
4425 // Operations on the Threads list for GC. These are not explicitly locked,
4426 // but the garbage collector must provide a safe context for them to run.
4427 // In particular, these things should never be called when the Threads_lock
4428 // is held by some other thread. (Note: the Safepoint abstraction also
4429 // uses the Threads_lock to guarantee this property. It also makes sure that
4430 // all threads gets blocked when exiting or starting).
4431
4432 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
4433 ALL_JAVA_THREADS(p) {
4434 p->oops_do(f, cf);
4435 }
4436 VMThread::vm_thread()->oops_do(f, cf);
4437 }
4438
4439 void Threads::change_thread_claim_parity() {
4440 // Set the new claim parity.
4441 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4442 "Not in range.");
4443 _thread_claim_parity++;
4444 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4445 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4446 "Not in range.");
4447 }
4448
4449 #ifdef ASSERT
4450 void Threads::assert_all_threads_claimed() {
4451 ALL_JAVA_THREADS(p) {
4452 const int thread_parity = p->oops_do_parity();
4453 assert((thread_parity == _thread_claim_parity),
4454 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4455 }
4456 VMThread* vmt = VMThread::vm_thread();
4457 const int thread_parity = vmt->oops_do_parity();
4458 assert((thread_parity == _thread_claim_parity),
4459 "VMThread " PTR_FORMAT " has incorrect parity %d != %d", p2i(vmt), thread_parity, _thread_claim_parity);
4460 }
4461 #endif // ASSERT
4462
4463 class ParallelOopsDoThreadClosure : public ThreadClosure {
4464 private:
4465 OopClosure* _f;
4466 CodeBlobClosure* _cf;
4467 public:
4468 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {}
4469 void do_thread(Thread* t) {
4470 t->oops_do(_f, _cf);
4471 }
4472 };
4473
4474 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
4475 ParallelOopsDoThreadClosure tc(f, cf);
4476 possibly_parallel_threads_do(is_par, &tc);
4477 }
4478
4479 #if INCLUDE_ALL_GCS
4480 // Used by ParallelScavenge
4481 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4482 ALL_JAVA_THREADS(p) {
4483 q->enqueue(new ThreadRootsTask(p));
4484 }
4485 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4486 }
4487
4488 // Used by Parallel Old
4489 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4490 ALL_JAVA_THREADS(p) {
4491 q->enqueue(new ThreadRootsMarkingTask(p));
4492 }
4493 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4494 }
4495 #endif // INCLUDE_ALL_GCS
4496
4497 void Threads::nmethods_do(CodeBlobClosure* cf) {
4498 ALL_JAVA_THREADS(p) {
4499 // This is used by the code cache sweeper to mark nmethods that are active
4500 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid
4501 // marking CodeCacheSweeperThread::_scanned_compiled_method as active.
4502 if(!p->is_Code_cache_sweeper_thread()) {
4503 p->nmethods_do(cf);
4504 }
4505 }
4506 }
4507
4508 void Threads::metadata_do(void f(Metadata*)) {
4509 ALL_JAVA_THREADS(p) {
4510 p->metadata_do(f);
4511 }
4512 }
4513
4514 class ThreadHandlesClosure : public ThreadClosure {
4515 void (*_f)(Metadata*);
4516 public:
4517 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4518 virtual void do_thread(Thread* thread) {
4519 thread->metadata_handles_do(_f);
4520 }
4521 };
4522
4523 void Threads::metadata_handles_do(void f(Metadata*)) {
4524 // Only walk the Handles in Thread.
4525 ThreadHandlesClosure handles_closure(f);
4526 threads_do(&handles_closure);
4527 }
4528
4529 void Threads::deoptimized_wrt_marked_nmethods() {
4530 ALL_JAVA_THREADS(p) {
4531 p->deoptimized_wrt_marked_nmethods();
4532 }
4533 }
4534
4535
4536 // Get count Java threads that are waiting to enter the specified monitor.
4537 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list,
4538 int count,
4539 address monitor) {
4540 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4541
4542 int i = 0;
4543 DO_JAVA_THREADS(t_list, p) {
4544 if (!p->can_call_java()) continue;
4545
4546 address pending = (address)p->current_pending_monitor();
4547 if (pending == monitor) { // found a match
4548 if (i < count) result->append(p); // save the first count matches
4549 i++;
4550 }
4551 }
4552
4553 return result;
4554 }
4555
4556
4557 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list,
4558 address owner) {
4559 // NULL owner means not locked so we can skip the search
4560 if (owner == NULL) return NULL;
4561
4562 DO_JAVA_THREADS(t_list, p) {
4563 // first, see if owner is the address of a Java thread
4564 if (owner == (address)p) return p;
4565 }
4566
4567 // Cannot assert on lack of success here since this function may be
4568 // used by code that is trying to report useful problem information
4569 // like deadlock detection.
4570 if (UseHeavyMonitors) return NULL;
4571
4572 // If we didn't find a matching Java thread and we didn't force use of
4573 // heavyweight monitors, then the owner is the stack address of the
4574 // Lock Word in the owning Java thread's stack.
4575 //
4576 JavaThread* the_owner = NULL;
4577 DO_JAVA_THREADS(t_list, q) {
4578 if (q->is_lock_owned(owner)) {
4579 the_owner = q;
4580 break;
4581 }
4582 }
4583
4584 // cannot assert on lack of success here; see above comment
4585 return the_owner;
4586 }
4587
4588 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4589 void Threads::print_on(outputStream* st, bool print_stacks,
4590 bool internal_format, bool print_concurrent_locks) {
4591 char buf[32];
4592 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4593
4594 st->print_cr("Full thread dump %s (%s %s):",
4595 Abstract_VM_Version::vm_name(),
4596 Abstract_VM_Version::vm_release(),
4597 Abstract_VM_Version::vm_info_string());
4598 st->cr();
4599
4600 #if INCLUDE_SERVICES
4601 // Dump concurrent locks
4602 ConcurrentLocksDump concurrent_locks;
4603 if (print_concurrent_locks) {
4604 concurrent_locks.dump_at_safepoint();
4605 }
4606 #endif // INCLUDE_SERVICES
4607
4608 ThreadsSMRSupport::print_info_on(st);
4609 st->cr();
4610
4611 ALL_JAVA_THREADS(p) {
4612 ResourceMark rm;
4613 p->print_on(st);
4614 if (print_stacks) {
4615 if (internal_format) {
4616 p->trace_stack();
4617 } else {
4618 p->print_stack_on(st);
4619 }
4620 }
4621 st->cr();
4622 #if INCLUDE_SERVICES
4623 if (print_concurrent_locks) {
4624 concurrent_locks.print_locks_on(p, st);
4625 }
4626 #endif // INCLUDE_SERVICES
4627 }
4628
4629 VMThread::vm_thread()->print_on(st);
4630 st->cr();
4631 Universe::heap()->print_gc_threads_on(st);
4632 WatcherThread* wt = WatcherThread::watcher_thread();
4633 if (wt != NULL) {
4634 wt->print_on(st);
4635 st->cr();
4636 }
4637
4638 st->flush();
4639 }
4640
4641 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
4642 int buflen, bool* found_current) {
4643 if (this_thread != NULL) {
4644 bool is_current = (current == this_thread);
4645 *found_current = *found_current || is_current;
4646 st->print("%s", is_current ? "=>" : " ");
4647
4648 st->print(PTR_FORMAT, p2i(this_thread));
4649 st->print(" ");
4650 this_thread->print_on_error(st, buf, buflen);
4651 st->cr();
4652 }
4653 }
4654
4655 class PrintOnErrorClosure : public ThreadClosure {
4656 outputStream* _st;
4657 Thread* _current;
4658 char* _buf;
4659 int _buflen;
4660 bool* _found_current;
4661 public:
4662 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
4663 int buflen, bool* found_current) :
4664 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
4665
4666 virtual void do_thread(Thread* thread) {
4667 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
4668 }
4669 };
4670
4671 // Threads::print_on_error() is called by fatal error handler. It's possible
4672 // that VM is not at safepoint and/or current thread is inside signal handler.
4673 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4674 // memory (even in resource area), it might deadlock the error handler.
4675 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4676 int buflen) {
4677 ThreadsSMRSupport::print_info_on(st);
4678 st->cr();
4679
4680 bool found_current = false;
4681 st->print_cr("Java Threads: ( => current thread )");
4682 ALL_JAVA_THREADS(thread) {
4683 print_on_error(thread, st, current, buf, buflen, &found_current);
4684 }
4685 st->cr();
4686
4687 st->print_cr("Other Threads:");
4688 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
4689 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
4690
4691 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
4692 Universe::heap()->gc_threads_do(&print_closure);
4693
4694 if (!found_current) {
4695 st->cr();
4696 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4697 current->print_on_error(st, buf, buflen);
4698 st->cr();
4699 }
4700 st->cr();
4701
4702 st->print_cr("Threads with active compile tasks:");
4703 print_threads_compiling(st, buf, buflen);
4704 }
4705
4706 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) {
4707 ALL_JAVA_THREADS(thread) {
4708 if (thread->is_Compiler_thread()) {
4709 CompilerThread* ct = (CompilerThread*) thread;
4710
4711 // Keep task in local variable for NULL check.
4712 // ct->_task might be set to NULL by concurring compiler thread
4713 // because it completed the compilation. The task is never freed,
4714 // though, just returned to a free list.
4715 CompileTask* task = ct->task();
4716 if (task != NULL) {
4717 thread->print_name_on_error(st, buf, buflen);
4718 task->print(st, NULL, true, true);
4719 }
4720 }
4721 }
4722 }
4723
4724
4725 // Internal SpinLock and Mutex
4726 // Based on ParkEvent
4727
4728 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4729 //
4730 // We employ SpinLocks _only for low-contention, fixed-length
4731 // short-duration critical sections where we're concerned
4732 // about native mutex_t or HotSpot Mutex:: latency.
4733 // The mux construct provides a spin-then-block mutual exclusion
4734 // mechanism.
4735 //
4736 // Testing has shown that contention on the ListLock guarding gFreeList
4737 // is common. If we implement ListLock as a simple SpinLock it's common
4738 // for the JVM to devolve to yielding with little progress. This is true
4739 // despite the fact that the critical sections protected by ListLock are
4740 // extremely short.
4741 //
4742 // TODO-FIXME: ListLock should be of type SpinLock.
4743 // We should make this a 1st-class type, integrated into the lock
4744 // hierarchy as leaf-locks. Critically, the SpinLock structure
4745 // should have sufficient padding to avoid false-sharing and excessive
4746 // cache-coherency traffic.
4747
4748
4749 typedef volatile int SpinLockT;
4750
4751 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4752 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4753 return; // normal fast-path return
4754 }
4755
4756 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4757 TEVENT(SpinAcquire - ctx);
4758 int ctr = 0;
4759 int Yields = 0;
4760 for (;;) {
4761 while (*adr != 0) {
4762 ++ctr;
4763 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4764 if (Yields > 5) {
4765 os::naked_short_sleep(1);
4766 } else {
4767 os::naked_yield();
4768 ++Yields;
4769 }
4770 } else {
4771 SpinPause();
4772 }
4773 }
4774 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4775 }
4776 }
4777
4778 void Thread::SpinRelease(volatile int * adr) {
4779 assert(*adr != 0, "invariant");
4780 OrderAccess::fence(); // guarantee at least release consistency.
4781 // Roach-motel semantics.
4782 // It's safe if subsequent LDs and STs float "up" into the critical section,
4783 // but prior LDs and STs within the critical section can't be allowed
4784 // to reorder or float past the ST that releases the lock.
4785 // Loads and stores in the critical section - which appear in program
4786 // order before the store that releases the lock - must also appear
4787 // before the store that releases the lock in memory visibility order.
4788 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4789 // the ST of 0 into the lock-word which releases the lock, so fence
4790 // more than covers this on all platforms.
4791 *adr = 0;
4792 }
4793
4794 // muxAcquire and muxRelease:
4795 //
4796 // * muxAcquire and muxRelease support a single-word lock-word construct.
4797 // The LSB of the word is set IFF the lock is held.
4798 // The remainder of the word points to the head of a singly-linked list
4799 // of threads blocked on the lock.
4800 //
4801 // * The current implementation of muxAcquire-muxRelease uses its own
4802 // dedicated Thread._MuxEvent instance. If we're interested in
4803 // minimizing the peak number of extant ParkEvent instances then
4804 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4805 // as certain invariants were satisfied. Specifically, care would need
4806 // to be taken with regards to consuming unpark() "permits".
4807 // A safe rule of thumb is that a thread would never call muxAcquire()
4808 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4809 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4810 // consume an unpark() permit intended for monitorenter, for instance.
4811 // One way around this would be to widen the restricted-range semaphore
4812 // implemented in park(). Another alternative would be to provide
4813 // multiple instances of the PlatformEvent() for each thread. One
4814 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4815 //
4816 // * Usage:
4817 // -- Only as leaf locks
4818 // -- for short-term locking only as muxAcquire does not perform
4819 // thread state transitions.
4820 //
4821 // Alternatives:
4822 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4823 // but with parking or spin-then-park instead of pure spinning.
4824 // * Use Taura-Oyama-Yonenzawa locks.
4825 // * It's possible to construct a 1-0 lock if we encode the lockword as
4826 // (List,LockByte). Acquire will CAS the full lockword while Release
4827 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4828 // acquiring threads use timers (ParkTimed) to detect and recover from
4829 // the stranding window. Thread/Node structures must be aligned on 256-byte
4830 // boundaries by using placement-new.
4831 // * Augment MCS with advisory back-link fields maintained with CAS().
4832 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4833 // The validity of the backlinks must be ratified before we trust the value.
4834 // If the backlinks are invalid the exiting thread must back-track through the
4835 // the forward links, which are always trustworthy.
4836 // * Add a successor indication. The LockWord is currently encoded as
4837 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4838 // to provide the usual futile-wakeup optimization.
4839 // See RTStt for details.
4840 // * Consider schedctl.sc_nopreempt to cover the critical section.
4841 //
4842
4843
4844 const intptr_t LOCKBIT = 1;
4845
4846 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4847 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4848 if (w == 0) return;
4849 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4850 return;
4851 }
4852
4853 TEVENT(muxAcquire - Contention);
4854 ParkEvent * const Self = Thread::current()->_MuxEvent;
4855 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4856 for (;;) {
4857 int its = (os::is_MP() ? 100 : 0) + 1;
4858
4859 // Optional spin phase: spin-then-park strategy
4860 while (--its >= 0) {
4861 w = *Lock;
4862 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4863 return;
4864 }
4865 }
4866
4867 Self->reset();
4868 Self->OnList = intptr_t(Lock);
4869 // The following fence() isn't _strictly necessary as the subsequent
4870 // CAS() both serializes execution and ratifies the fetched *Lock value.
4871 OrderAccess::fence();
4872 for (;;) {
4873 w = *Lock;
4874 if ((w & LOCKBIT) == 0) {
4875 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4876 Self->OnList = 0; // hygiene - allows stronger asserts
4877 return;
4878 }
4879 continue; // Interference -- *Lock changed -- Just retry
4880 }
4881 assert(w & LOCKBIT, "invariant");
4882 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4883 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4884 }
4885
4886 while (Self->OnList != 0) {
4887 Self->park();
4888 }
4889 }
4890 }
4891
4892 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4893 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0);
4894 if (w == 0) return;
4895 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4896 return;
4897 }
4898
4899 TEVENT(muxAcquire - Contention);
4900 ParkEvent * ReleaseAfter = NULL;
4901 if (ev == NULL) {
4902 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4903 }
4904 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4905 for (;;) {
4906 guarantee(ev->OnList == 0, "invariant");
4907 int its = (os::is_MP() ? 100 : 0) + 1;
4908
4909 // Optional spin phase: spin-then-park strategy
4910 while (--its >= 0) {
4911 w = *Lock;
4912 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4913 if (ReleaseAfter != NULL) {
4914 ParkEvent::Release(ReleaseAfter);
4915 }
4916 return;
4917 }
4918 }
4919
4920 ev->reset();
4921 ev->OnList = intptr_t(Lock);
4922 // The following fence() isn't _strictly necessary as the subsequent
4923 // CAS() both serializes execution and ratifies the fetched *Lock value.
4924 OrderAccess::fence();
4925 for (;;) {
4926 w = *Lock;
4927 if ((w & LOCKBIT) == 0) {
4928 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) {
4929 ev->OnList = 0;
4930 // We call ::Release while holding the outer lock, thus
4931 // artificially lengthening the critical section.
4932 // Consider deferring the ::Release() until the subsequent unlock(),
4933 // after we've dropped the outer lock.
4934 if (ReleaseAfter != NULL) {
4935 ParkEvent::Release(ReleaseAfter);
4936 }
4937 return;
4938 }
4939 continue; // Interference -- *Lock changed -- Just retry
4940 }
4941 assert(w & LOCKBIT, "invariant");
4942 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4943 if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4944 }
4945
4946 while (ev->OnList != 0) {
4947 ev->park();
4948 }
4949 }
4950 }
4951
4952 // Release() must extract a successor from the list and then wake that thread.
4953 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4954 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4955 // Release() would :
4956 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4957 // (B) Extract a successor from the private list "in-hand"
4958 // (C) attempt to CAS() the residual back into *Lock over null.
4959 // If there were any newly arrived threads and the CAS() would fail.
4960 // In that case Release() would detach the RATs, re-merge the list in-hand
4961 // with the RATs and repeat as needed. Alternately, Release() might
4962 // detach and extract a successor, but then pass the residual list to the wakee.
4963 // The wakee would be responsible for reattaching and remerging before it
4964 // competed for the lock.
4965 //
4966 // Both "pop" and DMR are immune from ABA corruption -- there can be
4967 // multiple concurrent pushers, but only one popper or detacher.
4968 // This implementation pops from the head of the list. This is unfair,
4969 // but tends to provide excellent throughput as hot threads remain hot.
4970 // (We wake recently run threads first).
4971 //
4972 // All paths through muxRelease() will execute a CAS.
4973 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4974 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4975 // executed within the critical section are complete and globally visible before the
4976 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4977 void Thread::muxRelease(volatile intptr_t * Lock) {
4978 for (;;) {
4979 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT);
4980 assert(w & LOCKBIT, "invariant");
4981 if (w == LOCKBIT) return;
4982 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4983 assert(List != NULL, "invariant");
4984 assert(List->OnList == intptr_t(Lock), "invariant");
4985 ParkEvent * const nxt = List->ListNext;
4986 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4987
4988 // The following CAS() releases the lock and pops the head element.
4989 // The CAS() also ratifies the previously fetched lock-word value.
4990 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) {
4991 continue;
4992 }
4993 List->OnList = 0;
4994 OrderAccess::fence();
4995 List->unpark();
4996 return;
4997 }
4998 }
4999
5000
5001 void Threads::verify() {
5002 ALL_JAVA_THREADS(p) {
5003 p->verify();
5004 }
5005 VMThread* thread = VMThread::vm_thread();
5006 if (thread != NULL) thread->verify();
5007 }