1 /*
2 * Copyright (c) 1997, 2015, 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 "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/codeCacheExtensions.hpp"
32 #include "code/scopeDesc.hpp"
33 #include "compiler/compileBroker.hpp"
34 #include "gc/shared/gcId.hpp"
35 #include "gc/shared/gcLocker.inline.hpp"
36 #include "gc/shared/workgroup.hpp"
37 #include "interpreter/interpreter.hpp"
38 #include "interpreter/linkResolver.hpp"
39 #include "interpreter/oopMapCache.hpp"
40 #include "jvmtifiles/jvmtiEnv.hpp"
41 #include "logging/logConfiguration.hpp"
42 #include "memory/metaspaceShared.hpp"
43 #include "memory/oopFactory.hpp"
44 #include "memory/universe.inline.hpp"
45 #include "oops/instanceKlass.hpp"
46 #include "oops/objArrayOop.hpp"
47 #include "oops/oop.inline.hpp"
48 #include "oops/symbol.hpp"
49 #include "oops/verifyOopClosure.hpp"
50 #include "prims/jvm_misc.hpp"
51 #include "prims/jvmtiExport.hpp"
52 #include "prims/jvmtiThreadState.hpp"
53 #include "prims/privilegedStack.hpp"
54 #include "runtime/arguments.hpp"
55 #include "runtime/atomic.inline.hpp"
56 #include "runtime/biasedLocking.hpp"
57 #include "runtime/commandLineFlagConstraintList.hpp"
58 #include "runtime/commandLineFlagRangeList.hpp"
59 #include "runtime/deoptimization.hpp"
60 #include "runtime/fprofiler.hpp"
61 #include "runtime/frame.inline.hpp"
62 #include "runtime/globals.hpp"
63 #include "runtime/init.hpp"
64 #include "runtime/interfaceSupport.hpp"
65 #include "runtime/java.hpp"
66 #include "runtime/javaCalls.hpp"
67 #include "runtime/jniPeriodicChecker.hpp"
68 #include "runtime/memprofiler.hpp"
69 #include "runtime/mutexLocker.hpp"
70 #include "runtime/objectMonitor.hpp"
71 #include "runtime/orderAccess.inline.hpp"
72 #include "runtime/osThread.hpp"
73 #include "runtime/safepoint.hpp"
74 #include "runtime/sharedRuntime.hpp"
75 #include "runtime/statSampler.hpp"
76 #include "runtime/stubRoutines.hpp"
77 #include "runtime/sweeper.hpp"
78 #include "runtime/task.hpp"
79 #include "runtime/thread.inline.hpp"
80 #include "runtime/threadCritical.hpp"
81 #include "runtime/threadLocalStorage.hpp"
82 #include "runtime/vframe.hpp"
83 #include "runtime/vframeArray.hpp"
84 #include "runtime/vframe_hp.hpp"
85 #include "runtime/vmThread.hpp"
86 #include "runtime/vm_operations.hpp"
87 #include "runtime/vm_version.hpp"
88 #include "services/attachListener.hpp"
89 #include "services/management.hpp"
90 #include "services/memTracker.hpp"
91 #include "services/threadService.hpp"
92 #include "trace/traceMacros.hpp"
93 #include "trace/tracing.hpp"
94 #include "utilities/defaultStream.hpp"
95 #include "utilities/dtrace.hpp"
96 #include "utilities/events.hpp"
97 #include "utilities/macros.hpp"
98 #include "utilities/preserveException.hpp"
99 #if INCLUDE_ALL_GCS
100 #include "gc/cms/concurrentMarkSweepThread.hpp"
101 #include "gc/g1/concurrentMarkThread.inline.hpp"
102 #include "gc/parallel/pcTasks.hpp"
103 #endif // INCLUDE_ALL_GCS
104 #if INCLUDE_JVMCI
105 #include "jvmci/jvmciCompiler.hpp"
106 #include "jvmci/jvmciRuntime.hpp"
107 #endif
108 #ifdef COMPILER1
109 #include "c1/c1_Compiler.hpp"
110 #endif
111 #ifdef COMPILER2
112 #include "opto/c2compiler.hpp"
113 #include "opto/idealGraphPrinter.hpp"
114 #endif
115 #if INCLUDE_RTM_OPT
116 #include "runtime/rtmLocking.hpp"
117 #endif
118
119 #ifdef DTRACE_ENABLED
120
121 // Only bother with this argument setup if dtrace is available
122
123 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
124 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
125
126 #define DTRACE_THREAD_PROBE(probe, javathread) \
127 { \
128 ResourceMark rm(this); \
129 int len = 0; \
130 const char* name = (javathread)->get_thread_name(); \
131 len = strlen(name); \
132 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
133 (char *) name, len, \
134 java_lang_Thread::thread_id((javathread)->threadObj()), \
135 (uintptr_t) (javathread)->osthread()->thread_id(), \
136 java_lang_Thread::is_daemon((javathread)->threadObj())); \
137 }
138
139 #else // ndef DTRACE_ENABLED
140
141 #define DTRACE_THREAD_PROBE(probe, javathread)
142
143 #endif // ndef DTRACE_ENABLED
144
145
146 // Class hierarchy
147 // - Thread
148 // - VMThread
149 // - WatcherThread
150 // - ConcurrentMarkSweepThread
151 // - JavaThread
152 // - CompilerThread
153
154 // ======= Thread ========
155 // Support for forcing alignment of thread objects for biased locking
156 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
157 if (UseBiasedLocking) {
158 const int alignment = markOopDesc::biased_lock_alignment;
159 size_t aligned_size = size + (alignment - sizeof(intptr_t));
160 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
161 : AllocateHeap(aligned_size, flags, CURRENT_PC,
162 AllocFailStrategy::RETURN_NULL);
163 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
164 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
165 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
166 "JavaThread alignment code overflowed allocated storage");
167 if (TraceBiasedLocking) {
168 if (aligned_addr != real_malloc_addr) {
169 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
170 p2i(real_malloc_addr), p2i(aligned_addr));
171 }
172 }
173 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
174 return aligned_addr;
175 } else {
176 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
177 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
178 }
179 }
180
181 void Thread::operator delete(void* p) {
182 if (UseBiasedLocking) {
183 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
184 FreeHeap(real_malloc_addr);
185 } else {
186 FreeHeap(p);
187 }
188 }
189
190
191 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
192 // JavaThread
193
194
195 Thread::Thread() {
196 // stack and get_thread
197 set_stack_base(NULL);
198 set_stack_size(0);
199 set_self_raw_id(0);
200 set_lgrp_id(-1);
201 DEBUG_ONLY(clear_suspendible_thread();)
202
203 // allocated data structures
204 set_osthread(NULL);
205 set_resource_area(new (mtThread)ResourceArea());
206 DEBUG_ONLY(_current_resource_mark = NULL;)
207 set_handle_area(new (mtThread) HandleArea(NULL));
208 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
209 set_active_handles(NULL);
210 set_free_handle_block(NULL);
211 set_last_handle_mark(NULL);
212
213 // This initial value ==> never claimed.
214 _oops_do_parity = 0;
215
216 // the handle mark links itself to last_handle_mark
217 new HandleMark(this);
218
219 // plain initialization
220 debug_only(_owned_locks = NULL;)
221 debug_only(_allow_allocation_count = 0;)
222 NOT_PRODUCT(_allow_safepoint_count = 0;)
223 NOT_PRODUCT(_skip_gcalot = false;)
224 _jvmti_env_iteration_count = 0;
225 set_allocated_bytes(0);
226 _vm_operation_started_count = 0;
227 _vm_operation_completed_count = 0;
228 _current_pending_monitor = NULL;
229 _current_pending_monitor_is_from_java = true;
230 _current_waiting_monitor = NULL;
231 _num_nested_signal = 0;
232 omFreeList = NULL;
233 omFreeCount = 0;
234 omFreeProvision = 32;
235 omInUseList = NULL;
236 omInUseCount = 0;
237
238 #ifdef ASSERT
239 _visited_for_critical_count = false;
240 #endif
241
242 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
243 Monitor::_safepoint_check_sometimes);
244 _suspend_flags = 0;
245
246 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
247 _hashStateX = os::random();
248 _hashStateY = 842502087;
249 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
250 _hashStateW = 273326509;
251
252 _OnTrap = 0;
253 _schedctl = NULL;
254 _Stalled = 0;
255 _TypeTag = 0x2BAD;
256
257 // Many of the following fields are effectively final - immutable
258 // Note that nascent threads can't use the Native Monitor-Mutex
259 // construct until the _MutexEvent is initialized ...
260 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
261 // we might instead use a stack of ParkEvents that we could provision on-demand.
262 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
263 // and ::Release()
264 _ParkEvent = ParkEvent::Allocate(this);
265 _SleepEvent = ParkEvent::Allocate(this);
266 _MutexEvent = ParkEvent::Allocate(this);
267 _MuxEvent = ParkEvent::Allocate(this);
268
269 #ifdef CHECK_UNHANDLED_OOPS
270 if (CheckUnhandledOops) {
271 _unhandled_oops = new UnhandledOops(this);
272 }
273 #endif // CHECK_UNHANDLED_OOPS
274 #ifdef ASSERT
275 if (UseBiasedLocking) {
276 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
277 assert(this == _real_malloc_address ||
278 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
279 "bug in forced alignment of thread objects");
280 }
281 #endif // ASSERT
282 }
283
284 // Non-inlined version to be used where thread.inline.hpp shouldn't be included.
285 Thread* Thread::current_noinline() {
286 return Thread::current();
287 }
288
289 void Thread::initialize_thread_local_storage() {
290 // Note: Make sure this method only calls
291 // non-blocking operations. Otherwise, it might not work
292 // with the thread-startup/safepoint interaction.
293
294 // During Java thread startup, safepoint code should allow this
295 // method to complete because it may need to allocate memory to
296 // store information for the new thread.
297
298 // initialize structure dependent on thread local storage
299 ThreadLocalStorage::set_thread(this);
300 }
301
302 void Thread::record_stack_base_and_size() {
303 set_stack_base(os::current_stack_base());
304 set_stack_size(os::current_stack_size());
305 if (is_Java_thread()) {
306 ((JavaThread*) this)->set_stack_overflow_limit();
307 ((JavaThread*) this)->set_reserved_stack_activation((intptr_t*)stack_base());
308 }
309 // CR 7190089: on Solaris, primordial thread's stack is adjusted
310 // in initialize_thread(). Without the adjustment, stack size is
311 // incorrect if stack is set to unlimited (ulimit -s unlimited).
312 // So far, only Solaris has real implementation of initialize_thread().
313 //
314 // set up any platform-specific state.
315 os::initialize_thread(this);
316
317 #if INCLUDE_NMT
318 // record thread's native stack, stack grows downward
319 address stack_low_addr = stack_base() - stack_size();
320 MemTracker::record_thread_stack(stack_low_addr, stack_size());
321 #endif // INCLUDE_NMT
322 }
323
324
325 Thread::~Thread() {
326 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
327 ObjectSynchronizer::omFlush(this);
328
329 EVENT_THREAD_DESTRUCT(this);
330
331 // stack_base can be NULL if the thread is never started or exited before
332 // record_stack_base_and_size called. Although, we would like to ensure
333 // that all started threads do call record_stack_base_and_size(), there is
334 // not proper way to enforce that.
335 #if INCLUDE_NMT
336 if (_stack_base != NULL) {
337 address low_stack_addr = stack_base() - stack_size();
338 MemTracker::release_thread_stack(low_stack_addr, stack_size());
339 #ifdef ASSERT
340 set_stack_base(NULL);
341 #endif
342 }
343 #endif // INCLUDE_NMT
344
345 // deallocate data structures
346 delete resource_area();
347 // since the handle marks are using the handle area, we have to deallocated the root
348 // handle mark before deallocating the thread's handle area,
349 assert(last_handle_mark() != NULL, "check we have an element");
350 delete last_handle_mark();
351 assert(last_handle_mark() == NULL, "check we have reached the end");
352
353 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
354 // We NULL out the fields for good hygiene.
355 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
356 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
357 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
358 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
359
360 delete handle_area();
361 delete metadata_handles();
362
363 // osthread() can be NULL, if creation of thread failed.
364 if (osthread() != NULL) os::free_thread(osthread());
365
366 delete _SR_lock;
367
368 // clear thread local storage if the Thread is deleting itself
369 if (this == Thread::current()) {
370 ThreadLocalStorage::set_thread(NULL);
371 } else {
372 // In the case where we're not the current thread, invalidate all the
373 // caches in case some code tries to get the current thread or the
374 // thread that was destroyed, and gets stale information.
375 ThreadLocalStorage::invalidate_all();
376 }
377 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
378 }
379
380 // NOTE: dummy function for assertion purpose.
381 void Thread::run() {
382 ShouldNotReachHere();
383 }
384
385 #ifdef ASSERT
386 // Private method to check for dangling thread pointer
387 void check_for_dangling_thread_pointer(Thread *thread) {
388 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
389 "possibility of dangling Thread pointer");
390 }
391 #endif
392
393 ThreadPriority Thread::get_priority(const Thread* const thread) {
394 ThreadPriority priority;
395 // Can return an error!
396 (void)os::get_priority(thread, priority);
397 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
398 return priority;
399 }
400
401 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
402 debug_only(check_for_dangling_thread_pointer(thread);)
403 // Can return an error!
404 (void)os::set_priority(thread, priority);
405 }
406
407
408 void Thread::start(Thread* thread) {
409 // Start is different from resume in that its safety is guaranteed by context or
410 // being called from a Java method synchronized on the Thread object.
411 if (!DisableStartThread) {
412 if (thread->is_Java_thread()) {
413 // Initialize the thread state to RUNNABLE before starting this thread.
414 // Can not set it after the thread started because we do not know the
415 // exact thread state at that time. It could be in MONITOR_WAIT or
416 // in SLEEPING or some other state.
417 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
418 java_lang_Thread::RUNNABLE);
419 }
420 os::start_thread(thread);
421 }
422 }
423
424 // Enqueue a VM_Operation to do the job for us - sometime later
425 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
426 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
427 VMThread::execute(vm_stop);
428 }
429
430
431 // Check if an external suspend request has completed (or has been
432 // cancelled). Returns true if the thread is externally suspended and
433 // false otherwise.
434 //
435 // The bits parameter returns information about the code path through
436 // the routine. Useful for debugging:
437 //
438 // set in is_ext_suspend_completed():
439 // 0x00000001 - routine was entered
440 // 0x00000010 - routine return false at end
441 // 0x00000100 - thread exited (return false)
442 // 0x00000200 - suspend request cancelled (return false)
443 // 0x00000400 - thread suspended (return true)
444 // 0x00001000 - thread is in a suspend equivalent state (return true)
445 // 0x00002000 - thread is native and walkable (return true)
446 // 0x00004000 - thread is native_trans and walkable (needed retry)
447 //
448 // set in wait_for_ext_suspend_completion():
449 // 0x00010000 - routine was entered
450 // 0x00020000 - suspend request cancelled before loop (return false)
451 // 0x00040000 - thread suspended before loop (return true)
452 // 0x00080000 - suspend request cancelled in loop (return false)
453 // 0x00100000 - thread suspended in loop (return true)
454 // 0x00200000 - suspend not completed during retry loop (return false)
455
456 // Helper class for tracing suspend wait debug bits.
457 //
458 // 0x00000100 indicates that the target thread exited before it could
459 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
460 // 0x00080000 each indicate a cancelled suspend request so they don't
461 // count as wait failures either.
462 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
463
464 class TraceSuspendDebugBits : public StackObj {
465 private:
466 JavaThread * jt;
467 bool is_wait;
468 bool called_by_wait; // meaningful when !is_wait
469 uint32_t * bits;
470
471 public:
472 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
473 uint32_t *_bits) {
474 jt = _jt;
475 is_wait = _is_wait;
476 called_by_wait = _called_by_wait;
477 bits = _bits;
478 }
479
480 ~TraceSuspendDebugBits() {
481 if (!is_wait) {
482 #if 1
483 // By default, don't trace bits for is_ext_suspend_completed() calls.
484 // That trace is very chatty.
485 return;
486 #else
487 if (!called_by_wait) {
488 // If tracing for is_ext_suspend_completed() is enabled, then only
489 // trace calls to it from wait_for_ext_suspend_completion()
490 return;
491 }
492 #endif
493 }
494
495 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
496 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
497 MutexLocker ml(Threads_lock); // needed for get_thread_name()
498 ResourceMark rm;
499
500 tty->print_cr(
501 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
502 jt->get_thread_name(), *bits);
503
504 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
505 }
506 }
507 }
508 };
509 #undef DEBUG_FALSE_BITS
510
511
512 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
513 uint32_t *bits) {
514 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
515
516 bool did_trans_retry = false; // only do thread_in_native_trans retry once
517 bool do_trans_retry; // flag to force the retry
518
519 *bits |= 0x00000001;
520
521 do {
522 do_trans_retry = false;
523
524 if (is_exiting()) {
525 // Thread is in the process of exiting. This is always checked
526 // first to reduce the risk of dereferencing a freed JavaThread.
527 *bits |= 0x00000100;
528 return false;
529 }
530
531 if (!is_external_suspend()) {
532 // Suspend request is cancelled. This is always checked before
533 // is_ext_suspended() to reduce the risk of a rogue resume
534 // confusing the thread that made the suspend request.
535 *bits |= 0x00000200;
536 return false;
537 }
538
539 if (is_ext_suspended()) {
540 // thread is suspended
541 *bits |= 0x00000400;
542 return true;
543 }
544
545 // Now that we no longer do hard suspends of threads running
546 // native code, the target thread can be changing thread state
547 // while we are in this routine:
548 //
549 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
550 //
551 // We save a copy of the thread state as observed at this moment
552 // and make our decision about suspend completeness based on the
553 // copy. This closes the race where the thread state is seen as
554 // _thread_in_native_trans in the if-thread_blocked check, but is
555 // seen as _thread_blocked in if-thread_in_native_trans check.
556 JavaThreadState save_state = thread_state();
557
558 if (save_state == _thread_blocked && is_suspend_equivalent()) {
559 // If the thread's state is _thread_blocked and this blocking
560 // condition is known to be equivalent to a suspend, then we can
561 // consider the thread to be externally suspended. This means that
562 // the code that sets _thread_blocked has been modified to do
563 // self-suspension if the blocking condition releases. We also
564 // used to check for CONDVAR_WAIT here, but that is now covered by
565 // the _thread_blocked with self-suspension check.
566 //
567 // Return true since we wouldn't be here unless there was still an
568 // external suspend request.
569 *bits |= 0x00001000;
570 return true;
571 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
572 // Threads running native code will self-suspend on native==>VM/Java
573 // transitions. If its stack is walkable (should always be the case
574 // unless this function is called before the actual java_suspend()
575 // call), then the wait is done.
576 *bits |= 0x00002000;
577 return true;
578 } else if (!called_by_wait && !did_trans_retry &&
579 save_state == _thread_in_native_trans &&
580 frame_anchor()->walkable()) {
581 // The thread is transitioning from thread_in_native to another
582 // thread state. check_safepoint_and_suspend_for_native_trans()
583 // will force the thread to self-suspend. If it hasn't gotten
584 // there yet we may have caught the thread in-between the native
585 // code check above and the self-suspend. Lucky us. If we were
586 // called by wait_for_ext_suspend_completion(), then it
587 // will be doing the retries so we don't have to.
588 //
589 // Since we use the saved thread state in the if-statement above,
590 // there is a chance that the thread has already transitioned to
591 // _thread_blocked by the time we get here. In that case, we will
592 // make a single unnecessary pass through the logic below. This
593 // doesn't hurt anything since we still do the trans retry.
594
595 *bits |= 0x00004000;
596
597 // Once the thread leaves thread_in_native_trans for another
598 // thread state, we break out of this retry loop. We shouldn't
599 // need this flag to prevent us from getting back here, but
600 // sometimes paranoia is good.
601 did_trans_retry = true;
602
603 // We wait for the thread to transition to a more usable state.
604 for (int i = 1; i <= SuspendRetryCount; i++) {
605 // We used to do an "os::yield_all(i)" call here with the intention
606 // that yielding would increase on each retry. However, the parameter
607 // is ignored on Linux which means the yield didn't scale up. Waiting
608 // on the SR_lock below provides a much more predictable scale up for
609 // the delay. It also provides a simple/direct point to check for any
610 // safepoint requests from the VMThread
611
612 // temporarily drops SR_lock while doing wait with safepoint check
613 // (if we're a JavaThread - the WatcherThread can also call this)
614 // and increase delay with each retry
615 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
616
617 // check the actual thread state instead of what we saved above
618 if (thread_state() != _thread_in_native_trans) {
619 // the thread has transitioned to another thread state so
620 // try all the checks (except this one) one more time.
621 do_trans_retry = true;
622 break;
623 }
624 } // end retry loop
625
626
627 }
628 } while (do_trans_retry);
629
630 *bits |= 0x00000010;
631 return false;
632 }
633
634 // Wait for an external suspend request to complete (or be cancelled).
635 // Returns true if the thread is externally suspended and false otherwise.
636 //
637 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
638 uint32_t *bits) {
639 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
640 false /* !called_by_wait */, bits);
641
642 // local flag copies to minimize SR_lock hold time
643 bool is_suspended;
644 bool pending;
645 uint32_t reset_bits;
646
647 // set a marker so is_ext_suspend_completed() knows we are the caller
648 *bits |= 0x00010000;
649
650 // We use reset_bits to reinitialize the bits value at the top of
651 // each retry loop. This allows the caller to make use of any
652 // unused bits for their own marking purposes.
653 reset_bits = *bits;
654
655 {
656 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
657 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
658 delay, bits);
659 pending = is_external_suspend();
660 }
661 // must release SR_lock to allow suspension to complete
662
663 if (!pending) {
664 // A cancelled suspend request is the only false return from
665 // is_ext_suspend_completed() that keeps us from entering the
666 // retry loop.
667 *bits |= 0x00020000;
668 return false;
669 }
670
671 if (is_suspended) {
672 *bits |= 0x00040000;
673 return true;
674 }
675
676 for (int i = 1; i <= retries; i++) {
677 *bits = reset_bits; // reinit to only track last retry
678
679 // We used to do an "os::yield_all(i)" call here with the intention
680 // that yielding would increase on each retry. However, the parameter
681 // is ignored on Linux which means the yield didn't scale up. Waiting
682 // on the SR_lock below provides a much more predictable scale up for
683 // the delay. It also provides a simple/direct point to check for any
684 // safepoint requests from the VMThread
685
686 {
687 MutexLocker ml(SR_lock());
688 // wait with safepoint check (if we're a JavaThread - the WatcherThread
689 // can also call this) and increase delay with each retry
690 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
691
692 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
693 delay, bits);
694
695 // It is possible for the external suspend request to be cancelled
696 // (by a resume) before the actual suspend operation is completed.
697 // Refresh our local copy to see if we still need to wait.
698 pending = is_external_suspend();
699 }
700
701 if (!pending) {
702 // A cancelled suspend request is the only false return from
703 // is_ext_suspend_completed() that keeps us from staying in the
704 // retry loop.
705 *bits |= 0x00080000;
706 return false;
707 }
708
709 if (is_suspended) {
710 *bits |= 0x00100000;
711 return true;
712 }
713 } // end retry loop
714
715 // thread did not suspend after all our retries
716 *bits |= 0x00200000;
717 return false;
718 }
719
720 #ifndef PRODUCT
721 void JavaThread::record_jump(address target, address instr, const char* file,
722 int line) {
723
724 // This should not need to be atomic as the only way for simultaneous
725 // updates is via interrupts. Even then this should be rare or non-existent
726 // and we don't care that much anyway.
727
728 int index = _jmp_ring_index;
729 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
730 _jmp_ring[index]._target = (intptr_t) target;
731 _jmp_ring[index]._instruction = (intptr_t) instr;
732 _jmp_ring[index]._file = file;
733 _jmp_ring[index]._line = line;
734 }
735 #endif // PRODUCT
736
737 // Called by flat profiler
738 // Callers have already called wait_for_ext_suspend_completion
739 // The assertion for that is currently too complex to put here:
740 bool JavaThread::profile_last_Java_frame(frame* _fr) {
741 bool gotframe = false;
742 // self suspension saves needed state.
743 if (has_last_Java_frame() && _anchor.walkable()) {
744 *_fr = pd_last_frame();
745 gotframe = true;
746 }
747 return gotframe;
748 }
749
750 void Thread::interrupt(Thread* thread) {
751 debug_only(check_for_dangling_thread_pointer(thread);)
752 os::interrupt(thread);
753 }
754
755 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
756 debug_only(check_for_dangling_thread_pointer(thread);)
757 // Note: If clear_interrupted==false, this simply fetches and
758 // returns the value of the field osthread()->interrupted().
759 return os::is_interrupted(thread, clear_interrupted);
760 }
761
762
763 // GC Support
764 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
765 jint thread_parity = _oops_do_parity;
766 if (thread_parity != strong_roots_parity) {
767 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
768 if (res == thread_parity) {
769 return true;
770 } else {
771 guarantee(res == strong_roots_parity, "Or else what?");
772 return false;
773 }
774 }
775 return false;
776 }
777
778 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
779 active_handles()->oops_do(f);
780 // Do oop for ThreadShadow
781 f->do_oop((oop*)&_pending_exception);
782 handle_area()->oops_do(f);
783 }
784
785 void Thread::nmethods_do(CodeBlobClosure* cf) {
786 // no nmethods in a generic thread...
787 }
788
789 void Thread::metadata_handles_do(void f(Metadata*)) {
790 // Only walk the Handles in Thread.
791 if (metadata_handles() != NULL) {
792 for (int i = 0; i< metadata_handles()->length(); i++) {
793 f(metadata_handles()->at(i));
794 }
795 }
796 }
797
798 void Thread::print_on(outputStream* st) const {
799 // get_priority assumes osthread initialized
800 if (osthread() != NULL) {
801 int os_prio;
802 if (os::get_native_priority(this, &os_prio) == OS_OK) {
803 st->print("os_prio=%d ", os_prio);
804 }
805 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
806 ext().print_on(st);
807 osthread()->print_on(st);
808 }
809 debug_only(if (WizardMode) print_owned_locks_on(st);)
810 }
811
812 // Thread::print_on_error() is called by fatal error handler. Don't use
813 // any lock or allocate memory.
814 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
815 if (is_VM_thread()) st->print("VMThread");
816 else if (is_Compiler_thread()) st->print("CompilerThread");
817 else if (is_Java_thread()) st->print("JavaThread");
818 else if (is_GC_task_thread()) st->print("GCTaskThread");
819 else if (is_Watcher_thread()) st->print("WatcherThread");
820 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
821 else st->print("Thread");
822
823 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
824 p2i(_stack_base - _stack_size), p2i(_stack_base));
825
826 if (osthread()) {
827 st->print(" [id=%d]", osthread()->thread_id());
828 }
829 }
830
831 #ifdef ASSERT
832 void Thread::print_owned_locks_on(outputStream* st) const {
833 Monitor *cur = _owned_locks;
834 if (cur == NULL) {
835 st->print(" (no locks) ");
836 } else {
837 st->print_cr(" Locks owned:");
838 while (cur) {
839 cur->print_on(st);
840 cur = cur->next();
841 }
842 }
843 }
844
845 static int ref_use_count = 0;
846
847 bool Thread::owns_locks_but_compiled_lock() const {
848 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
849 if (cur != Compile_lock) return true;
850 }
851 return false;
852 }
853
854
855 #endif
856
857 #ifndef PRODUCT
858
859 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
860 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
861 // no threads which allow_vm_block's are held
862 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
863 // Check if current thread is allowed to block at a safepoint
864 if (!(_allow_safepoint_count == 0)) {
865 fatal("Possible safepoint reached by thread that does not allow it");
866 }
867 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
868 fatal("LEAF method calling lock?");
869 }
870
871 #ifdef ASSERT
872 if (potential_vm_operation && is_Java_thread()
873 && !Universe::is_bootstrapping()) {
874 // Make sure we do not hold any locks that the VM thread also uses.
875 // This could potentially lead to deadlocks
876 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
877 // Threads_lock is special, since the safepoint synchronization will not start before this is
878 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
879 // since it is used to transfer control between JavaThreads and the VMThread
880 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
881 if ((cur->allow_vm_block() &&
882 cur != Threads_lock &&
883 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
884 cur != VMOperationRequest_lock &&
885 cur != VMOperationQueue_lock) ||
886 cur->rank() == Mutex::special) {
887 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
888 }
889 }
890 }
891
892 if (GCALotAtAllSafepoints) {
893 // We could enter a safepoint here and thus have a gc
894 InterfaceSupport::check_gc_alot();
895 }
896 #endif
897 }
898 #endif
899
900 bool Thread::is_in_stack(address adr) const {
901 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
902 address end = os::current_stack_pointer();
903 // Allow non Java threads to call this without stack_base
904 if (_stack_base == NULL) return true;
905 if (stack_base() >= adr && adr >= end) return true;
906
907 return false;
908 }
909
910
911 bool Thread::is_in_usable_stack(address adr) const {
912 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackReservedPages + StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
913 size_t usable_stack_size = _stack_size - stack_guard_size;
914
915 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
916 }
917
918
919 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
920 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
921 // used for compilation in the future. If that change is made, the need for these methods
922 // should be revisited, and they should be removed if possible.
923
924 bool Thread::is_lock_owned(address adr) const {
925 return on_local_stack(adr);
926 }
927
928 bool Thread::set_as_starting_thread() {
929 // NOTE: this must be called inside the main thread.
930 return os::create_main_thread((JavaThread*)this);
931 }
932
933 static void initialize_class(Symbol* class_name, TRAPS) {
934 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
935 InstanceKlass::cast(klass)->initialize(CHECK);
936 }
937
938
939 // Creates the initial ThreadGroup
940 static Handle create_initial_thread_group(TRAPS) {
941 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
942 instanceKlassHandle klass (THREAD, k);
943
944 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
945 {
946 JavaValue result(T_VOID);
947 JavaCalls::call_special(&result,
948 system_instance,
949 klass,
950 vmSymbols::object_initializer_name(),
951 vmSymbols::void_method_signature(),
952 CHECK_NH);
953 }
954 Universe::set_system_thread_group(system_instance());
955
956 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
957 {
958 JavaValue result(T_VOID);
959 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
960 JavaCalls::call_special(&result,
961 main_instance,
962 klass,
963 vmSymbols::object_initializer_name(),
964 vmSymbols::threadgroup_string_void_signature(),
965 system_instance,
966 string,
967 CHECK_NH);
968 }
969 return main_instance;
970 }
971
972 // Creates the initial Thread
973 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
974 TRAPS) {
975 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
976 instanceKlassHandle klass (THREAD, k);
977 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
978
979 java_lang_Thread::set_thread(thread_oop(), thread);
980 java_lang_Thread::set_priority(thread_oop(), NormPriority);
981 thread->set_threadObj(thread_oop());
982
983 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
984
985 JavaValue result(T_VOID);
986 JavaCalls::call_special(&result, thread_oop,
987 klass,
988 vmSymbols::object_initializer_name(),
989 vmSymbols::threadgroup_string_void_signature(),
990 thread_group,
991 string,
992 CHECK_NULL);
993 return thread_oop();
994 }
995
996 static void call_initializeSystemClass(TRAPS) {
997 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
998 instanceKlassHandle klass (THREAD, k);
999
1000 JavaValue result(T_VOID);
1001 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1002 vmSymbols::void_method_signature(), CHECK);
1003 }
1004
1005 char java_runtime_name[128] = "";
1006 char java_runtime_version[128] = "";
1007
1008 // extract the JRE name from sun.misc.Version.java_runtime_name
1009 static const char* get_java_runtime_name(TRAPS) {
1010 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1011 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1012 fieldDescriptor fd;
1013 bool found = k != NULL &&
1014 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1015 vmSymbols::string_signature(), &fd);
1016 if (found) {
1017 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1018 if (name_oop == NULL) {
1019 return NULL;
1020 }
1021 const char* name = java_lang_String::as_utf8_string(name_oop,
1022 java_runtime_name,
1023 sizeof(java_runtime_name));
1024 return name;
1025 } else {
1026 return NULL;
1027 }
1028 }
1029
1030 // extract the JRE version from sun.misc.Version.java_runtime_version
1031 static const char* get_java_runtime_version(TRAPS) {
1032 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1033 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1034 fieldDescriptor fd;
1035 bool found = k != NULL &&
1036 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1037 vmSymbols::string_signature(), &fd);
1038 if (found) {
1039 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1040 if (name_oop == NULL) {
1041 return NULL;
1042 }
1043 const char* name = java_lang_String::as_utf8_string(name_oop,
1044 java_runtime_version,
1045 sizeof(java_runtime_version));
1046 return name;
1047 } else {
1048 return NULL;
1049 }
1050 }
1051
1052 // General purpose hook into Java code, run once when the VM is initialized.
1053 // The Java library method itself may be changed independently from the VM.
1054 static void call_postVMInitHook(TRAPS) {
1055 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1056 instanceKlassHandle klass (THREAD, k);
1057 if (klass.not_null()) {
1058 JavaValue result(T_VOID);
1059 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1060 vmSymbols::void_method_signature(),
1061 CHECK);
1062 }
1063 }
1064
1065 static void reset_vm_info_property(TRAPS) {
1066 // the vm info string
1067 ResourceMark rm(THREAD);
1068 const char *vm_info = VM_Version::vm_info_string();
1069
1070 // java.lang.System class
1071 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1072 instanceKlassHandle klass (THREAD, k);
1073
1074 // setProperty arguments
1075 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1076 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1077
1078 // return value
1079 JavaValue r(T_OBJECT);
1080
1081 // public static String setProperty(String key, String value);
1082 JavaCalls::call_static(&r,
1083 klass,
1084 vmSymbols::setProperty_name(),
1085 vmSymbols::string_string_string_signature(),
1086 key_str,
1087 value_str,
1088 CHECK);
1089 }
1090
1091
1092 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1093 bool daemon, TRAPS) {
1094 assert(thread_group.not_null(), "thread group should be specified");
1095 assert(threadObj() == NULL, "should only create Java thread object once");
1096
1097 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1098 instanceKlassHandle klass (THREAD, k);
1099 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1100
1101 java_lang_Thread::set_thread(thread_oop(), this);
1102 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1103 set_threadObj(thread_oop());
1104
1105 JavaValue result(T_VOID);
1106 if (thread_name != NULL) {
1107 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1108 // Thread gets assigned specified name and null target
1109 JavaCalls::call_special(&result,
1110 thread_oop,
1111 klass,
1112 vmSymbols::object_initializer_name(),
1113 vmSymbols::threadgroup_string_void_signature(),
1114 thread_group, // Argument 1
1115 name, // Argument 2
1116 THREAD);
1117 } else {
1118 // Thread gets assigned name "Thread-nnn" and null target
1119 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1120 JavaCalls::call_special(&result,
1121 thread_oop,
1122 klass,
1123 vmSymbols::object_initializer_name(),
1124 vmSymbols::threadgroup_runnable_void_signature(),
1125 thread_group, // Argument 1
1126 Handle(), // Argument 2
1127 THREAD);
1128 }
1129
1130
1131 if (daemon) {
1132 java_lang_Thread::set_daemon(thread_oop());
1133 }
1134
1135 if (HAS_PENDING_EXCEPTION) {
1136 return;
1137 }
1138
1139 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1140 Handle threadObj(THREAD, this->threadObj());
1141
1142 JavaCalls::call_special(&result,
1143 thread_group,
1144 group,
1145 vmSymbols::add_method_name(),
1146 vmSymbols::thread_void_signature(),
1147 threadObj, // Arg 1
1148 THREAD);
1149 }
1150
1151 // NamedThread -- non-JavaThread subclasses with multiple
1152 // uniquely named instances should derive from this.
1153 NamedThread::NamedThread() : Thread() {
1154 _name = NULL;
1155 _processed_thread = NULL;
1156 _gc_id = GCId::undefined();
1157 }
1158
1159 NamedThread::~NamedThread() {
1160 if (_name != NULL) {
1161 FREE_C_HEAP_ARRAY(char, _name);
1162 _name = NULL;
1163 }
1164 }
1165
1166 void NamedThread::set_name(const char* format, ...) {
1167 guarantee(_name == NULL, "Only get to set name once.");
1168 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1169 guarantee(_name != NULL, "alloc failure");
1170 va_list ap;
1171 va_start(ap, format);
1172 jio_vsnprintf(_name, max_name_len, format, ap);
1173 va_end(ap);
1174 }
1175
1176 void NamedThread::initialize_named_thread() {
1177 set_native_thread_name(name());
1178 }
1179
1180 void NamedThread::print_on(outputStream* st) const {
1181 st->print("\"%s\" ", name());
1182 Thread::print_on(st);
1183 st->cr();
1184 }
1185
1186
1187 // ======= WatcherThread ========
1188
1189 // The watcher thread exists to simulate timer interrupts. It should
1190 // be replaced by an abstraction over whatever native support for
1191 // timer interrupts exists on the platform.
1192
1193 WatcherThread* WatcherThread::_watcher_thread = NULL;
1194 bool WatcherThread::_startable = false;
1195 volatile bool WatcherThread::_should_terminate = false;
1196
1197 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1198 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1199 if (os::create_thread(this, os::watcher_thread)) {
1200 _watcher_thread = this;
1201
1202 // Set the watcher thread to the highest OS priority which should not be
1203 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1204 // is created. The only normal thread using this priority is the reference
1205 // handler thread, which runs for very short intervals only.
1206 // If the VMThread's priority is not lower than the WatcherThread profiling
1207 // will be inaccurate.
1208 os::set_priority(this, MaxPriority);
1209 if (!DisableStartThread) {
1210 os::start_thread(this);
1211 }
1212 }
1213 }
1214
1215 int WatcherThread::sleep() const {
1216 // The WatcherThread does not participate in the safepoint protocol
1217 // for the PeriodicTask_lock because it is not a JavaThread.
1218 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1219
1220 if (_should_terminate) {
1221 // check for termination before we do any housekeeping or wait
1222 return 0; // we did not sleep.
1223 }
1224
1225 // remaining will be zero if there are no tasks,
1226 // causing the WatcherThread to sleep until a task is
1227 // enrolled
1228 int remaining = PeriodicTask::time_to_wait();
1229 int time_slept = 0;
1230
1231 // we expect this to timeout - we only ever get unparked when
1232 // we should terminate or when a new task has been enrolled
1233 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1234
1235 jlong time_before_loop = os::javaTimeNanos();
1236
1237 while (true) {
1238 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1239 remaining);
1240 jlong now = os::javaTimeNanos();
1241
1242 if (remaining == 0) {
1243 // if we didn't have any tasks we could have waited for a long time
1244 // consider the time_slept zero and reset time_before_loop
1245 time_slept = 0;
1246 time_before_loop = now;
1247 } else {
1248 // need to recalculate since we might have new tasks in _tasks
1249 time_slept = (int) ((now - time_before_loop) / 1000000);
1250 }
1251
1252 // Change to task list or spurious wakeup of some kind
1253 if (timedout || _should_terminate) {
1254 break;
1255 }
1256
1257 remaining = PeriodicTask::time_to_wait();
1258 if (remaining == 0) {
1259 // Last task was just disenrolled so loop around and wait until
1260 // another task gets enrolled
1261 continue;
1262 }
1263
1264 remaining -= time_slept;
1265 if (remaining <= 0) {
1266 break;
1267 }
1268 }
1269
1270 return time_slept;
1271 }
1272
1273 void WatcherThread::run() {
1274 assert(this == watcher_thread(), "just checking");
1275
1276 this->record_stack_base_and_size();
1277 this->initialize_thread_local_storage();
1278 this->set_native_thread_name(this->name());
1279 this->set_active_handles(JNIHandleBlock::allocate_block());
1280 while (true) {
1281 assert(watcher_thread() == Thread::current(), "thread consistency check");
1282 assert(watcher_thread() == this, "thread consistency check");
1283
1284 // Calculate how long it'll be until the next PeriodicTask work
1285 // should be done, and sleep that amount of time.
1286 int time_waited = sleep();
1287
1288 if (is_error_reported()) {
1289 // A fatal error has happened, the error handler(VMError::report_and_die)
1290 // should abort JVM after creating an error log file. However in some
1291 // rare cases, the error handler itself might deadlock. Here we try to
1292 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1293 //
1294 // This code is in WatcherThread because WatcherThread wakes up
1295 // periodically so the fatal error handler doesn't need to do anything;
1296 // also because the WatcherThread is less likely to crash than other
1297 // threads.
1298
1299 for (;;) {
1300 if (!ShowMessageBoxOnError
1301 && (OnError == NULL || OnError[0] == '\0')
1302 && Arguments::abort_hook() == NULL) {
1303 os::sleep(this, ErrorLogTimeout * 60 * 1000, false);
1304 fdStream err(defaultStream::output_fd());
1305 err.print_raw_cr("# [ timer expired, abort... ]");
1306 // skip atexit/vm_exit/vm_abort hooks
1307 os::die();
1308 }
1309
1310 // Wake up 5 seconds later, the fatal handler may reset OnError or
1311 // ShowMessageBoxOnError when it is ready to abort.
1312 os::sleep(this, 5 * 1000, false);
1313 }
1314 }
1315
1316 if (_should_terminate) {
1317 // check for termination before posting the next tick
1318 break;
1319 }
1320
1321 PeriodicTask::real_time_tick(time_waited);
1322 }
1323
1324 // Signal that it is terminated
1325 {
1326 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1327 _watcher_thread = NULL;
1328 Terminator_lock->notify();
1329 }
1330
1331 // Thread destructor usually does this..
1332 ThreadLocalStorage::set_thread(NULL);
1333 }
1334
1335 void WatcherThread::start() {
1336 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1337
1338 if (watcher_thread() == NULL && _startable) {
1339 _should_terminate = false;
1340 // Create the single instance of WatcherThread
1341 new WatcherThread();
1342 }
1343 }
1344
1345 void WatcherThread::make_startable() {
1346 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1347 _startable = true;
1348 }
1349
1350 void WatcherThread::stop() {
1351 {
1352 // Follow normal safepoint aware lock enter protocol since the
1353 // WatcherThread is stopped by another JavaThread.
1354 MutexLocker ml(PeriodicTask_lock);
1355 _should_terminate = true;
1356
1357 WatcherThread* watcher = watcher_thread();
1358 if (watcher != NULL) {
1359 // unpark the WatcherThread so it can see that it should terminate
1360 watcher->unpark();
1361 }
1362 }
1363
1364 MutexLocker mu(Terminator_lock);
1365
1366 while (watcher_thread() != NULL) {
1367 // This wait should make safepoint checks, wait without a timeout,
1368 // and wait as a suspend-equivalent condition.
1369 //
1370 // Note: If the FlatProfiler is running, then this thread is waiting
1371 // for the WatcherThread to terminate and the WatcherThread, via the
1372 // FlatProfiler task, is waiting for the external suspend request on
1373 // this thread to complete. wait_for_ext_suspend_completion() will
1374 // eventually timeout, but that takes time. Making this wait a
1375 // suspend-equivalent condition solves that timeout problem.
1376 //
1377 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1378 Mutex::_as_suspend_equivalent_flag);
1379 }
1380 }
1381
1382 void WatcherThread::unpark() {
1383 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1384 PeriodicTask_lock->notify();
1385 }
1386
1387 void WatcherThread::print_on(outputStream* st) const {
1388 st->print("\"%s\" ", name());
1389 Thread::print_on(st);
1390 st->cr();
1391 }
1392
1393 // ======= JavaThread ========
1394
1395 #if INCLUDE_JVMCI
1396
1397 jlong* JavaThread::_jvmci_old_thread_counters;
1398
1399 bool jvmci_counters_include(JavaThread* thread) {
1400 oop threadObj = thread->threadObj();
1401 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
1402 }
1403
1404 void JavaThread::collect_counters(typeArrayOop array) {
1405 if (JVMCICounterSize > 0) {
1406 MutexLocker tl(Threads_lock);
1407 for (int i = 0; i < array->length(); i++) {
1408 array->long_at_put(i, _jvmci_old_thread_counters[i]);
1409 }
1410 for (JavaThread* tp = Threads::first(); tp != NULL; tp = tp->next()) {
1411 if (jvmci_counters_include(tp)) {
1412 for (int i = 0; i < array->length(); i++) {
1413 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
1414 }
1415 }
1416 }
1417 }
1418 }
1419
1420 #endif // INCLUDE_JVMCI
1421
1422 // A JavaThread is a normal Java thread
1423
1424 void JavaThread::initialize() {
1425 // Initialize fields
1426
1427 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1428 set_claimed_par_id(UINT_MAX);
1429
1430 set_saved_exception_pc(NULL);
1431 set_threadObj(NULL);
1432 _anchor.clear();
1433 set_entry_point(NULL);
1434 set_jni_functions(jni_functions());
1435 set_callee_target(NULL);
1436 set_vm_result(NULL);
1437 set_vm_result_2(NULL);
1438 set_vframe_array_head(NULL);
1439 set_vframe_array_last(NULL);
1440 set_deferred_locals(NULL);
1441 set_deopt_mark(NULL);
1442 set_deopt_nmethod(NULL);
1443 clear_must_deopt_id();
1444 set_monitor_chunks(NULL);
1445 set_next(NULL);
1446 set_thread_state(_thread_new);
1447 _terminated = _not_terminated;
1448 _privileged_stack_top = NULL;
1449 _array_for_gc = NULL;
1450 _suspend_equivalent = false;
1451 _in_deopt_handler = 0;
1452 _doing_unsafe_access = false;
1453 _stack_guard_state = stack_guard_unused;
1454 #if INCLUDE_JVMCI
1455 _pending_monitorenter = false;
1456 _pending_deoptimization = -1;
1457 _pending_failed_speculation = NULL;
1458 _pending_transfer_to_interpreter = false;
1459 _jvmci._alternate_call_target = NULL;
1460 assert(_jvmci._implicit_exception_pc == NULL, "must be");
1461 if (JVMCICounterSize > 0) {
1462 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
1463 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
1464 } else {
1465 _jvmci_counters = NULL;
1466 }
1467 #endif // INCLUDE_JVMCI
1468 _reserved_stack_activation = NULL; // stack base not known yet
1469 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1470 _exception_pc = 0;
1471 _exception_handler_pc = 0;
1472 _is_method_handle_return = 0;
1473 _jvmti_thread_state= NULL;
1474 _should_post_on_exceptions_flag = JNI_FALSE;
1475 _jvmti_get_loaded_classes_closure = NULL;
1476 _interp_only_mode = 0;
1477 _special_runtime_exit_condition = _no_async_condition;
1478 _pending_async_exception = NULL;
1479 _thread_stat = NULL;
1480 _thread_stat = new ThreadStatistics();
1481 _blocked_on_compilation = false;
1482 _jni_active_critical = 0;
1483 _pending_jni_exception_check_fn = NULL;
1484 _do_not_unlock_if_synchronized = false;
1485 _cached_monitor_info = NULL;
1486 _parker = Parker::Allocate(this);
1487
1488 #ifndef PRODUCT
1489 _jmp_ring_index = 0;
1490 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1491 record_jump(NULL, NULL, NULL, 0);
1492 }
1493 #endif // PRODUCT
1494
1495 set_thread_profiler(NULL);
1496 if (FlatProfiler::is_active()) {
1497 // This is where we would decide to either give each thread it's own profiler
1498 // or use one global one from FlatProfiler,
1499 // or up to some count of the number of profiled threads, etc.
1500 ThreadProfiler* pp = new ThreadProfiler();
1501 pp->engage();
1502 set_thread_profiler(pp);
1503 }
1504
1505 // Setup safepoint state info for this thread
1506 ThreadSafepointState::create(this);
1507
1508 debug_only(_java_call_counter = 0);
1509
1510 // JVMTI PopFrame support
1511 _popframe_condition = popframe_inactive;
1512 _popframe_preserved_args = NULL;
1513 _popframe_preserved_args_size = 0;
1514 _frames_to_pop_failed_realloc = 0;
1515
1516 pd_initialize();
1517 }
1518
1519 #if INCLUDE_ALL_GCS
1520 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1521 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1522 #endif // INCLUDE_ALL_GCS
1523
1524 JavaThread::JavaThread(bool is_attaching_via_jni) :
1525 Thread()
1526 #if INCLUDE_ALL_GCS
1527 , _satb_mark_queue(&_satb_mark_queue_set),
1528 _dirty_card_queue(&_dirty_card_queue_set)
1529 #endif // INCLUDE_ALL_GCS
1530 {
1531 initialize();
1532 if (is_attaching_via_jni) {
1533 _jni_attach_state = _attaching_via_jni;
1534 } else {
1535 _jni_attach_state = _not_attaching_via_jni;
1536 }
1537 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1538 }
1539
1540 bool JavaThread::reguard_stack(address cur_sp) {
1541 if (_stack_guard_state != stack_guard_yellow_disabled
1542 && _stack_guard_state != stack_guard_reserved_disabled) {
1543 return true; // Stack already guarded or guard pages not needed.
1544 }
1545
1546 if (register_stack_overflow()) {
1547 // For those architectures which have separate register and
1548 // memory stacks, we must check the register stack to see if
1549 // it has overflowed.
1550 return false;
1551 }
1552
1553 // Java code never executes within the yellow zone: the latter is only
1554 // there to provoke an exception during stack banging. If java code
1555 // is executing there, either StackShadowPages should be larger, or
1556 // some exception code in c1, c2 or the interpreter isn't unwinding
1557 // when it should.
1558 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1559 if (_stack_guard_state == stack_guard_yellow_disabled) {
1560 enable_stack_yellow_zone();
1561 if (reserved_stack_activation() != (intptr_t*)stack_base()) {
1562 set_reserved_stack_activation((intptr_t*)stack_base());
1563 }
1564 } else if (_stack_guard_state == stack_guard_reserved_disabled) {
1565 set_reserved_stack_activation((intptr_t*)stack_base());
1566 enable_stack_reserved_zone();
1567 }
1568 return true;
1569 }
1570
1571 bool JavaThread::reguard_stack(void) {
1572 return reguard_stack(os::current_stack_pointer());
1573 }
1574
1575
1576 void JavaThread::block_if_vm_exited() {
1577 if (_terminated == _vm_exited) {
1578 // _vm_exited is set at safepoint, and Threads_lock is never released
1579 // we will block here forever
1580 Threads_lock->lock_without_safepoint_check();
1581 ShouldNotReachHere();
1582 }
1583 }
1584
1585
1586 // Remove this ifdef when C1 is ported to the compiler interface.
1587 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1588 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1589
1590 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1591 Thread()
1592 #if INCLUDE_ALL_GCS
1593 , _satb_mark_queue(&_satb_mark_queue_set),
1594 _dirty_card_queue(&_dirty_card_queue_set)
1595 #endif // INCLUDE_ALL_GCS
1596 {
1597 initialize();
1598 _jni_attach_state = _not_attaching_via_jni;
1599 set_entry_point(entry_point);
1600 // Create the native thread itself.
1601 // %note runtime_23
1602 os::ThreadType thr_type = os::java_thread;
1603 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1604 os::java_thread;
1605 os::create_thread(this, thr_type, stack_sz);
1606 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1607 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1608 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1609 // the exception consists of creating the exception object & initializing it, initialization
1610 // will leave the VM via a JavaCall and then all locks must be unlocked).
1611 //
1612 // The thread is still suspended when we reach here. Thread must be explicit started
1613 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1614 // by calling Threads:add. The reason why this is not done here, is because the thread
1615 // object must be fully initialized (take a look at JVM_Start)
1616 }
1617
1618 JavaThread::~JavaThread() {
1619
1620 // JSR166 -- return the parker to the free list
1621 Parker::Release(_parker);
1622 _parker = NULL;
1623
1624 // Free any remaining previous UnrollBlock
1625 vframeArray* old_array = vframe_array_last();
1626
1627 if (old_array != NULL) {
1628 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1629 old_array->set_unroll_block(NULL);
1630 delete old_info;
1631 delete old_array;
1632 }
1633
1634 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1635 if (deferred != NULL) {
1636 // This can only happen if thread is destroyed before deoptimization occurs.
1637 assert(deferred->length() != 0, "empty array!");
1638 do {
1639 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1640 deferred->remove_at(0);
1641 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1642 delete dlv;
1643 } while (deferred->length() != 0);
1644 delete deferred;
1645 }
1646
1647 // All Java related clean up happens in exit
1648 ThreadSafepointState::destroy(this);
1649 if (_thread_profiler != NULL) delete _thread_profiler;
1650 if (_thread_stat != NULL) delete _thread_stat;
1651
1652 #if INCLUDE_JVMCI
1653 if (JVMCICounterSize > 0) {
1654 if (jvmci_counters_include(this)) {
1655 for (int i = 0; i < JVMCICounterSize; i++) {
1656 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1657 }
1658 }
1659 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
1660 }
1661 #endif // INCLUDE_JVMCI
1662 }
1663
1664
1665 // The first routine called by a new Java thread
1666 void JavaThread::run() {
1667 // initialize thread-local alloc buffer related fields
1668 this->initialize_tlab();
1669
1670 // used to test validity of stack trace backs
1671 this->record_base_of_stack_pointer();
1672
1673 // Record real stack base and size.
1674 this->record_stack_base_and_size();
1675
1676 // Initialize thread local storage; set before calling MutexLocker
1677 this->initialize_thread_local_storage();
1678
1679 this->create_stack_guard_pages();
1680
1681 this->cache_global_variables();
1682
1683 // Thread is now sufficient initialized to be handled by the safepoint code as being
1684 // in the VM. Change thread state from _thread_new to _thread_in_vm
1685 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1686
1687 assert(JavaThread::current() == this, "sanity check");
1688 assert(!Thread::current()->owns_locks(), "sanity check");
1689
1690 DTRACE_THREAD_PROBE(start, this);
1691
1692 // This operation might block. We call that after all safepoint checks for a new thread has
1693 // been completed.
1694 this->set_active_handles(JNIHandleBlock::allocate_block());
1695
1696 if (JvmtiExport::should_post_thread_life()) {
1697 JvmtiExport::post_thread_start(this);
1698 }
1699
1700 EventThreadStart event;
1701 if (event.should_commit()) {
1702 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1703 event.commit();
1704 }
1705
1706 // We call another function to do the rest so we are sure that the stack addresses used
1707 // from there will be lower than the stack base just computed
1708 thread_main_inner();
1709
1710 // Note, thread is no longer valid at this point!
1711 }
1712
1713
1714 void JavaThread::thread_main_inner() {
1715 assert(JavaThread::current() == this, "sanity check");
1716 assert(this->threadObj() != NULL, "just checking");
1717
1718 // Execute thread entry point unless this thread has a pending exception
1719 // or has been stopped before starting.
1720 // Note: Due to JVM_StopThread we can have pending exceptions already!
1721 if (!this->has_pending_exception() &&
1722 !java_lang_Thread::is_stillborn(this->threadObj())) {
1723 {
1724 ResourceMark rm(this);
1725 this->set_native_thread_name(this->get_thread_name());
1726 }
1727 HandleMark hm(this);
1728 this->entry_point()(this, this);
1729 }
1730
1731 DTRACE_THREAD_PROBE(stop, this);
1732
1733 this->exit(false);
1734 delete this;
1735 }
1736
1737
1738 static void ensure_join(JavaThread* thread) {
1739 // We do not need to grap the Threads_lock, since we are operating on ourself.
1740 Handle threadObj(thread, thread->threadObj());
1741 assert(threadObj.not_null(), "java thread object must exist");
1742 ObjectLocker lock(threadObj, thread);
1743 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1744 thread->clear_pending_exception();
1745 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1746 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1747 // Clear the native thread instance - this makes isAlive return false and allows the join()
1748 // to complete once we've done the notify_all below
1749 java_lang_Thread::set_thread(threadObj(), NULL);
1750 lock.notify_all(thread);
1751 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1752 thread->clear_pending_exception();
1753 }
1754
1755
1756 // For any new cleanup additions, please check to see if they need to be applied to
1757 // cleanup_failed_attach_current_thread as well.
1758 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1759 assert(this == JavaThread::current(), "thread consistency check");
1760
1761 HandleMark hm(this);
1762 Handle uncaught_exception(this, this->pending_exception());
1763 this->clear_pending_exception();
1764 Handle threadObj(this, this->threadObj());
1765 assert(threadObj.not_null(), "Java thread object should be created");
1766
1767 if (get_thread_profiler() != NULL) {
1768 get_thread_profiler()->disengage();
1769 ResourceMark rm;
1770 get_thread_profiler()->print(get_thread_name());
1771 }
1772
1773
1774 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1775 {
1776 EXCEPTION_MARK;
1777
1778 CLEAR_PENDING_EXCEPTION;
1779 }
1780 if (!destroy_vm) {
1781 if (uncaught_exception.not_null()) {
1782 EXCEPTION_MARK;
1783 // Call method Thread.dispatchUncaughtException().
1784 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1785 JavaValue result(T_VOID);
1786 JavaCalls::call_virtual(&result,
1787 threadObj, thread_klass,
1788 vmSymbols::dispatchUncaughtException_name(),
1789 vmSymbols::throwable_void_signature(),
1790 uncaught_exception,
1791 THREAD);
1792 if (HAS_PENDING_EXCEPTION) {
1793 ResourceMark rm(this);
1794 jio_fprintf(defaultStream::error_stream(),
1795 "\nException: %s thrown from the UncaughtExceptionHandler"
1796 " in thread \"%s\"\n",
1797 pending_exception()->klass()->external_name(),
1798 get_thread_name());
1799 CLEAR_PENDING_EXCEPTION;
1800 }
1801 }
1802
1803 // Called before the java thread exit since we want to read info
1804 // from java_lang_Thread object
1805 EventThreadEnd event;
1806 if (event.should_commit()) {
1807 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1808 event.commit();
1809 }
1810
1811 // Call after last event on thread
1812 EVENT_THREAD_EXIT(this);
1813
1814 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1815 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1816 // is deprecated anyhow.
1817 if (!is_Compiler_thread()) {
1818 int count = 3;
1819 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1820 EXCEPTION_MARK;
1821 JavaValue result(T_VOID);
1822 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1823 JavaCalls::call_virtual(&result,
1824 threadObj, thread_klass,
1825 vmSymbols::exit_method_name(),
1826 vmSymbols::void_method_signature(),
1827 THREAD);
1828 CLEAR_PENDING_EXCEPTION;
1829 }
1830 }
1831 // notify JVMTI
1832 if (JvmtiExport::should_post_thread_life()) {
1833 JvmtiExport::post_thread_end(this);
1834 }
1835
1836 // We have notified the agents that we are exiting, before we go on,
1837 // we must check for a pending external suspend request and honor it
1838 // in order to not surprise the thread that made the suspend request.
1839 while (true) {
1840 {
1841 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1842 if (!is_external_suspend()) {
1843 set_terminated(_thread_exiting);
1844 ThreadService::current_thread_exiting(this);
1845 break;
1846 }
1847 // Implied else:
1848 // Things get a little tricky here. We have a pending external
1849 // suspend request, but we are holding the SR_lock so we
1850 // can't just self-suspend. So we temporarily drop the lock
1851 // and then self-suspend.
1852 }
1853
1854 ThreadBlockInVM tbivm(this);
1855 java_suspend_self();
1856
1857 // We're done with this suspend request, but we have to loop around
1858 // and check again. Eventually we will get SR_lock without a pending
1859 // external suspend request and will be able to mark ourselves as
1860 // exiting.
1861 }
1862 // no more external suspends are allowed at this point
1863 } else {
1864 // before_exit() has already posted JVMTI THREAD_END events
1865 }
1866
1867 // Notify waiters on thread object. This has to be done after exit() is called
1868 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1869 // group should have the destroyed bit set before waiters are notified).
1870 ensure_join(this);
1871 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1872
1873 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1874 // held by this thread must be released. The spec does not distinguish
1875 // between JNI-acquired and regular Java monitors. We can only see
1876 // regular Java monitors here if monitor enter-exit matching is broken.
1877 //
1878 // Optionally release any monitors for regular JavaThread exits. This
1879 // is provided as a work around for any bugs in monitor enter-exit
1880 // matching. This can be expensive so it is not enabled by default.
1881 // ObjectMonitor::Knob_ExitRelease is a superset of the
1882 // JNIDetachReleasesMonitors option.
1883 //
1884 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1885 // ObjectSynchronizer::release_monitors_owned_by_thread().
1886 if ((exit_type == jni_detach && JNIDetachReleasesMonitors) ||
1887 ObjectMonitor::Knob_ExitRelease) {
1888 // Sanity check even though JNI DetachCurrentThread() would have
1889 // returned JNI_ERR if there was a Java frame. JavaThread exit
1890 // should be done executing Java code by the time we get here.
1891 assert(!this->has_last_Java_frame(),
1892 "should not have a Java frame when detaching or exiting");
1893 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1894 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1895 }
1896
1897 // These things needs to be done while we are still a Java Thread. Make sure that thread
1898 // is in a consistent state, in case GC happens
1899 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1900
1901 if (active_handles() != NULL) {
1902 JNIHandleBlock* block = active_handles();
1903 set_active_handles(NULL);
1904 JNIHandleBlock::release_block(block);
1905 }
1906
1907 if (free_handle_block() != NULL) {
1908 JNIHandleBlock* block = free_handle_block();
1909 set_free_handle_block(NULL);
1910 JNIHandleBlock::release_block(block);
1911 }
1912
1913 // These have to be removed while this is still a valid thread.
1914 remove_stack_guard_pages();
1915
1916 if (UseTLAB) {
1917 tlab().make_parsable(true); // retire TLAB
1918 }
1919
1920 if (JvmtiEnv::environments_might_exist()) {
1921 JvmtiExport::cleanup_thread(this);
1922 }
1923
1924 // We must flush any deferred card marks before removing a thread from
1925 // the list of active threads.
1926 Universe::heap()->flush_deferred_store_barrier(this);
1927 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1928
1929 #if INCLUDE_ALL_GCS
1930 // We must flush the G1-related buffers before removing a thread
1931 // from the list of active threads. We must do this after any deferred
1932 // card marks have been flushed (above) so that any entries that are
1933 // added to the thread's dirty card queue as a result are not lost.
1934 if (UseG1GC) {
1935 flush_barrier_queues();
1936 }
1937 #endif // INCLUDE_ALL_GCS
1938
1939 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1940 Threads::remove(this);
1941 }
1942
1943 #if INCLUDE_ALL_GCS
1944 // Flush G1-related queues.
1945 void JavaThread::flush_barrier_queues() {
1946 satb_mark_queue().flush();
1947 dirty_card_queue().flush();
1948 }
1949
1950 void JavaThread::initialize_queues() {
1951 assert(!SafepointSynchronize::is_at_safepoint(),
1952 "we should not be at a safepoint");
1953
1954 ObjPtrQueue& satb_queue = satb_mark_queue();
1955 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1956 // The SATB queue should have been constructed with its active
1957 // field set to false.
1958 assert(!satb_queue.is_active(), "SATB queue should not be active");
1959 assert(satb_queue.is_empty(), "SATB queue should be empty");
1960 // If we are creating the thread during a marking cycle, we should
1961 // set the active field of the SATB queue to true.
1962 if (satb_queue_set.is_active()) {
1963 satb_queue.set_active(true);
1964 }
1965
1966 DirtyCardQueue& dirty_queue = dirty_card_queue();
1967 // The dirty card queue should have been constructed with its
1968 // active field set to true.
1969 assert(dirty_queue.is_active(), "dirty card queue should be active");
1970 }
1971 #endif // INCLUDE_ALL_GCS
1972
1973 void JavaThread::cleanup_failed_attach_current_thread() {
1974 if (get_thread_profiler() != NULL) {
1975 get_thread_profiler()->disengage();
1976 ResourceMark rm;
1977 get_thread_profiler()->print(get_thread_name());
1978 }
1979
1980 if (active_handles() != NULL) {
1981 JNIHandleBlock* block = active_handles();
1982 set_active_handles(NULL);
1983 JNIHandleBlock::release_block(block);
1984 }
1985
1986 if (free_handle_block() != NULL) {
1987 JNIHandleBlock* block = free_handle_block();
1988 set_free_handle_block(NULL);
1989 JNIHandleBlock::release_block(block);
1990 }
1991
1992 // These have to be removed while this is still a valid thread.
1993 remove_stack_guard_pages();
1994
1995 if (UseTLAB) {
1996 tlab().make_parsable(true); // retire TLAB, if any
1997 }
1998
1999 #if INCLUDE_ALL_GCS
2000 if (UseG1GC) {
2001 flush_barrier_queues();
2002 }
2003 #endif // INCLUDE_ALL_GCS
2004
2005 Threads::remove(this);
2006 delete this;
2007 }
2008
2009
2010
2011
2012 JavaThread* JavaThread::active() {
2013 Thread* thread = ThreadLocalStorage::thread();
2014 assert(thread != NULL, "just checking");
2015 if (thread->is_Java_thread()) {
2016 return (JavaThread*) thread;
2017 } else {
2018 assert(thread->is_VM_thread(), "this must be a vm thread");
2019 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2020 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2021 assert(ret->is_Java_thread(), "must be a Java thread");
2022 return ret;
2023 }
2024 }
2025
2026 bool JavaThread::is_lock_owned(address adr) const {
2027 if (Thread::is_lock_owned(adr)) return true;
2028
2029 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2030 if (chunk->contains(adr)) return true;
2031 }
2032
2033 return false;
2034 }
2035
2036
2037 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2038 chunk->set_next(monitor_chunks());
2039 set_monitor_chunks(chunk);
2040 }
2041
2042 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2043 guarantee(monitor_chunks() != NULL, "must be non empty");
2044 if (monitor_chunks() == chunk) {
2045 set_monitor_chunks(chunk->next());
2046 } else {
2047 MonitorChunk* prev = monitor_chunks();
2048 while (prev->next() != chunk) prev = prev->next();
2049 prev->set_next(chunk->next());
2050 }
2051 }
2052
2053 // JVM support.
2054
2055 // Note: this function shouldn't block if it's called in
2056 // _thread_in_native_trans state (such as from
2057 // check_special_condition_for_native_trans()).
2058 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2059
2060 if (has_last_Java_frame() && has_async_condition()) {
2061 // If we are at a polling page safepoint (not a poll return)
2062 // then we must defer async exception because live registers
2063 // will be clobbered by the exception path. Poll return is
2064 // ok because the call we a returning from already collides
2065 // with exception handling registers and so there is no issue.
2066 // (The exception handling path kills call result registers but
2067 // this is ok since the exception kills the result anyway).
2068
2069 if (is_at_poll_safepoint()) {
2070 // if the code we are returning to has deoptimized we must defer
2071 // the exception otherwise live registers get clobbered on the
2072 // exception path before deoptimization is able to retrieve them.
2073 //
2074 RegisterMap map(this, false);
2075 frame caller_fr = last_frame().sender(&map);
2076 assert(caller_fr.is_compiled_frame(), "what?");
2077 if (caller_fr.is_deoptimized_frame()) {
2078 if (TraceExceptions) {
2079 ResourceMark rm;
2080 tty->print_cr("deferred async exception at compiled safepoint");
2081 }
2082 return;
2083 }
2084 }
2085 }
2086
2087 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2088 if (condition == _no_async_condition) {
2089 // Conditions have changed since has_special_runtime_exit_condition()
2090 // was called:
2091 // - if we were here only because of an external suspend request,
2092 // then that was taken care of above (or cancelled) so we are done
2093 // - if we were here because of another async request, then it has
2094 // been cleared between the has_special_runtime_exit_condition()
2095 // and now so again we are done
2096 return;
2097 }
2098
2099 // Check for pending async. exception
2100 if (_pending_async_exception != NULL) {
2101 // Only overwrite an already pending exception, if it is not a threadDeath.
2102 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2103
2104 // We cannot call Exceptions::_throw(...) here because we cannot block
2105 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2106
2107 if (TraceExceptions) {
2108 ResourceMark rm;
2109 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
2110 if (has_last_Java_frame()) {
2111 frame f = last_frame();
2112 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
2113 }
2114 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2115 }
2116 _pending_async_exception = NULL;
2117 clear_has_async_exception();
2118 }
2119 }
2120
2121 if (check_unsafe_error &&
2122 condition == _async_unsafe_access_error && !has_pending_exception()) {
2123 condition = _no_async_condition; // done
2124 switch (thread_state()) {
2125 case _thread_in_vm: {
2126 JavaThread* THREAD = this;
2127 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2128 }
2129 case _thread_in_native: {
2130 ThreadInVMfromNative tiv(this);
2131 JavaThread* THREAD = this;
2132 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2133 }
2134 case _thread_in_Java: {
2135 ThreadInVMfromJava tiv(this);
2136 JavaThread* THREAD = this;
2137 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2138 }
2139 default:
2140 ShouldNotReachHere();
2141 }
2142 }
2143
2144 assert(condition == _no_async_condition || has_pending_exception() ||
2145 (!check_unsafe_error && condition == _async_unsafe_access_error),
2146 "must have handled the async condition, if no exception");
2147 }
2148
2149 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2150 //
2151 // Check for pending external suspend. Internal suspend requests do
2152 // not use handle_special_runtime_exit_condition().
2153 // If JNIEnv proxies are allowed, don't self-suspend if the target
2154 // thread is not the current thread. In older versions of jdbx, jdbx
2155 // threads could call into the VM with another thread's JNIEnv so we
2156 // can be here operating on behalf of a suspended thread (4432884).
2157 bool do_self_suspend = is_external_suspend_with_lock();
2158 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2159 //
2160 // Because thread is external suspended the safepoint code will count
2161 // thread as at a safepoint. This can be odd because we can be here
2162 // as _thread_in_Java which would normally transition to _thread_blocked
2163 // at a safepoint. We would like to mark the thread as _thread_blocked
2164 // before calling java_suspend_self like all other callers of it but
2165 // we must then observe proper safepoint protocol. (We can't leave
2166 // _thread_blocked with a safepoint in progress). However we can be
2167 // here as _thread_in_native_trans so we can't use a normal transition
2168 // constructor/destructor pair because they assert on that type of
2169 // transition. We could do something like:
2170 //
2171 // JavaThreadState state = thread_state();
2172 // set_thread_state(_thread_in_vm);
2173 // {
2174 // ThreadBlockInVM tbivm(this);
2175 // java_suspend_self()
2176 // }
2177 // set_thread_state(_thread_in_vm_trans);
2178 // if (safepoint) block;
2179 // set_thread_state(state);
2180 //
2181 // but that is pretty messy. Instead we just go with the way the
2182 // code has worked before and note that this is the only path to
2183 // java_suspend_self that doesn't put the thread in _thread_blocked
2184 // mode.
2185
2186 frame_anchor()->make_walkable(this);
2187 java_suspend_self();
2188
2189 // We might be here for reasons in addition to the self-suspend request
2190 // so check for other async requests.
2191 }
2192
2193 if (check_asyncs) {
2194 check_and_handle_async_exceptions();
2195 }
2196 }
2197
2198 void JavaThread::send_thread_stop(oop java_throwable) {
2199 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2200 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2201 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2202
2203 // Do not throw asynchronous exceptions against the compiler thread
2204 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2205 if (!can_call_java()) return;
2206
2207 {
2208 // Actually throw the Throwable against the target Thread - however
2209 // only if there is no thread death exception installed already.
2210 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2211 // If the topmost frame is a runtime stub, then we are calling into
2212 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2213 // must deoptimize the caller before continuing, as the compiled exception handler table
2214 // may not be valid
2215 if (has_last_Java_frame()) {
2216 frame f = last_frame();
2217 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2218 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2219 RegisterMap reg_map(this, UseBiasedLocking);
2220 frame compiled_frame = f.sender(®_map);
2221 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2222 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2223 }
2224 }
2225 }
2226
2227 // Set async. pending exception in thread.
2228 set_pending_async_exception(java_throwable);
2229
2230 if (TraceExceptions) {
2231 ResourceMark rm;
2232 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2233 }
2234 // for AbortVMOnException flag
2235 Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2236 }
2237 }
2238
2239
2240 // Interrupt thread so it will wake up from a potential wait()
2241 Thread::interrupt(this);
2242 }
2243
2244 // External suspension mechanism.
2245 //
2246 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2247 // to any VM_locks and it is at a transition
2248 // Self-suspension will happen on the transition out of the vm.
2249 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2250 //
2251 // Guarantees on return:
2252 // + Target thread will not execute any new bytecode (that's why we need to
2253 // force a safepoint)
2254 // + Target thread will not enter any new monitors
2255 //
2256 void JavaThread::java_suspend() {
2257 { MutexLocker mu(Threads_lock);
2258 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2259 return;
2260 }
2261 }
2262
2263 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2264 if (!is_external_suspend()) {
2265 // a racing resume has cancelled us; bail out now
2266 return;
2267 }
2268
2269 // suspend is done
2270 uint32_t debug_bits = 0;
2271 // Warning: is_ext_suspend_completed() may temporarily drop the
2272 // SR_lock to allow the thread to reach a stable thread state if
2273 // it is currently in a transient thread state.
2274 if (is_ext_suspend_completed(false /* !called_by_wait */,
2275 SuspendRetryDelay, &debug_bits)) {
2276 return;
2277 }
2278 }
2279
2280 VM_ForceSafepoint vm_suspend;
2281 VMThread::execute(&vm_suspend);
2282 }
2283
2284 // Part II of external suspension.
2285 // A JavaThread self suspends when it detects a pending external suspend
2286 // request. This is usually on transitions. It is also done in places
2287 // where continuing to the next transition would surprise the caller,
2288 // e.g., monitor entry.
2289 //
2290 // Returns the number of times that the thread self-suspended.
2291 //
2292 // Note: DO NOT call java_suspend_self() when you just want to block current
2293 // thread. java_suspend_self() is the second stage of cooperative
2294 // suspension for external suspend requests and should only be used
2295 // to complete an external suspend request.
2296 //
2297 int JavaThread::java_suspend_self() {
2298 int ret = 0;
2299
2300 // we are in the process of exiting so don't suspend
2301 if (is_exiting()) {
2302 clear_external_suspend();
2303 return ret;
2304 }
2305
2306 assert(_anchor.walkable() ||
2307 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2308 "must have walkable stack");
2309
2310 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2311
2312 assert(!this->is_ext_suspended(),
2313 "a thread trying to self-suspend should not already be suspended");
2314
2315 if (this->is_suspend_equivalent()) {
2316 // If we are self-suspending as a result of the lifting of a
2317 // suspend equivalent condition, then the suspend_equivalent
2318 // flag is not cleared until we set the ext_suspended flag so
2319 // that wait_for_ext_suspend_completion() returns consistent
2320 // results.
2321 this->clear_suspend_equivalent();
2322 }
2323
2324 // A racing resume may have cancelled us before we grabbed SR_lock
2325 // above. Or another external suspend request could be waiting for us
2326 // by the time we return from SR_lock()->wait(). The thread
2327 // that requested the suspension may already be trying to walk our
2328 // stack and if we return now, we can change the stack out from under
2329 // it. This would be a "bad thing (TM)" and cause the stack walker
2330 // to crash. We stay self-suspended until there are no more pending
2331 // external suspend requests.
2332 while (is_external_suspend()) {
2333 ret++;
2334 this->set_ext_suspended();
2335
2336 // _ext_suspended flag is cleared by java_resume()
2337 while (is_ext_suspended()) {
2338 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2339 }
2340 }
2341
2342 return ret;
2343 }
2344
2345 #ifdef ASSERT
2346 // verify the JavaThread has not yet been published in the Threads::list, and
2347 // hence doesn't need protection from concurrent access at this stage
2348 void JavaThread::verify_not_published() {
2349 if (!Threads_lock->owned_by_self()) {
2350 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2351 assert(!Threads::includes(this),
2352 "java thread shouldn't have been published yet!");
2353 } else {
2354 assert(!Threads::includes(this),
2355 "java thread shouldn't have been published yet!");
2356 }
2357 }
2358 #endif
2359
2360 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2361 // progress or when _suspend_flags is non-zero.
2362 // Current thread needs to self-suspend if there is a suspend request and/or
2363 // block if a safepoint is in progress.
2364 // Async exception ISN'T checked.
2365 // Note only the ThreadInVMfromNative transition can call this function
2366 // directly and when thread state is _thread_in_native_trans
2367 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2368 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2369
2370 JavaThread *curJT = JavaThread::current();
2371 bool do_self_suspend = thread->is_external_suspend();
2372
2373 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2374
2375 // If JNIEnv proxies are allowed, don't self-suspend if the target
2376 // thread is not the current thread. In older versions of jdbx, jdbx
2377 // threads could call into the VM with another thread's JNIEnv so we
2378 // can be here operating on behalf of a suspended thread (4432884).
2379 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2380 JavaThreadState state = thread->thread_state();
2381
2382 // We mark this thread_blocked state as a suspend-equivalent so
2383 // that a caller to is_ext_suspend_completed() won't be confused.
2384 // The suspend-equivalent state is cleared by java_suspend_self().
2385 thread->set_suspend_equivalent();
2386
2387 // If the safepoint code sees the _thread_in_native_trans state, it will
2388 // wait until the thread changes to other thread state. There is no
2389 // guarantee on how soon we can obtain the SR_lock and complete the
2390 // self-suspend request. It would be a bad idea to let safepoint wait for
2391 // too long. Temporarily change the state to _thread_blocked to
2392 // let the VM thread know that this thread is ready for GC. The problem
2393 // of changing thread state is that safepoint could happen just after
2394 // java_suspend_self() returns after being resumed, and VM thread will
2395 // see the _thread_blocked state. We must check for safepoint
2396 // after restoring the state and make sure we won't leave while a safepoint
2397 // is in progress.
2398 thread->set_thread_state(_thread_blocked);
2399 thread->java_suspend_self();
2400 thread->set_thread_state(state);
2401 // Make sure new state is seen by VM thread
2402 if (os::is_MP()) {
2403 if (UseMembar) {
2404 // Force a fence between the write above and read below
2405 OrderAccess::fence();
2406 } else {
2407 // Must use this rather than serialization page in particular on Windows
2408 InterfaceSupport::serialize_memory(thread);
2409 }
2410 }
2411 }
2412
2413 if (SafepointSynchronize::do_call_back()) {
2414 // If we are safepointing, then block the caller which may not be
2415 // the same as the target thread (see above).
2416 SafepointSynchronize::block(curJT);
2417 }
2418
2419 if (thread->is_deopt_suspend()) {
2420 thread->clear_deopt_suspend();
2421 RegisterMap map(thread, false);
2422 frame f = thread->last_frame();
2423 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2424 f = f.sender(&map);
2425 }
2426 if (f.id() == thread->must_deopt_id()) {
2427 thread->clear_must_deopt_id();
2428 f.deoptimize(thread);
2429 } else {
2430 fatal("missed deoptimization!");
2431 }
2432 }
2433 }
2434
2435 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2436 // progress or when _suspend_flags is non-zero.
2437 // Current thread needs to self-suspend if there is a suspend request and/or
2438 // block if a safepoint is in progress.
2439 // Also check for pending async exception (not including unsafe access error).
2440 // Note only the native==>VM/Java barriers can call this function and when
2441 // thread state is _thread_in_native_trans.
2442 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2443 check_safepoint_and_suspend_for_native_trans(thread);
2444
2445 if (thread->has_async_exception()) {
2446 // We are in _thread_in_native_trans state, don't handle unsafe
2447 // access error since that may block.
2448 thread->check_and_handle_async_exceptions(false);
2449 }
2450 }
2451
2452 // This is a variant of the normal
2453 // check_special_condition_for_native_trans with slightly different
2454 // semantics for use by critical native wrappers. It does all the
2455 // normal checks but also performs the transition back into
2456 // thread_in_Java state. This is required so that critical natives
2457 // can potentially block and perform a GC if they are the last thread
2458 // exiting the GC_locker.
2459 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2460 check_special_condition_for_native_trans(thread);
2461
2462 // Finish the transition
2463 thread->set_thread_state(_thread_in_Java);
2464
2465 if (thread->do_critical_native_unlock()) {
2466 ThreadInVMfromJavaNoAsyncException tiv(thread);
2467 GC_locker::unlock_critical(thread);
2468 thread->clear_critical_native_unlock();
2469 }
2470 }
2471
2472 // We need to guarantee the Threads_lock here, since resumes are not
2473 // allowed during safepoint synchronization
2474 // Can only resume from an external suspension
2475 void JavaThread::java_resume() {
2476 assert_locked_or_safepoint(Threads_lock);
2477
2478 // Sanity check: thread is gone, has started exiting or the thread
2479 // was not externally suspended.
2480 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2481 return;
2482 }
2483
2484 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2485
2486 clear_external_suspend();
2487
2488 if (is_ext_suspended()) {
2489 clear_ext_suspended();
2490 SR_lock()->notify_all();
2491 }
2492 }
2493
2494 void JavaThread::create_stack_guard_pages() {
2495 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2496 address low_addr = stack_base() - stack_size();
2497 size_t len = (StackReservedPages + StackYellowPages + StackRedPages) * os::vm_page_size();
2498
2499 int allocate = os::allocate_stack_guard_pages();
2500 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2501
2502 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2503 warning("Attempt to allocate stack guard pages failed.");
2504 return;
2505 }
2506
2507 if (os::guard_memory((char *) low_addr, len)) {
2508 _stack_guard_state = stack_guard_enabled;
2509 } else {
2510 warning("Attempt to protect stack guard pages failed.");
2511 if (os::uncommit_memory((char *) low_addr, len)) {
2512 warning("Attempt to deallocate stack guard pages failed.");
2513 }
2514 }
2515 }
2516
2517 void JavaThread::remove_stack_guard_pages() {
2518 assert(Thread::current() == this, "from different thread");
2519 if (_stack_guard_state == stack_guard_unused) return;
2520 address low_addr = stack_base() - stack_size();
2521 size_t len = (StackReservedPages + StackYellowPages + StackRedPages) * os::vm_page_size();
2522
2523 if (os::allocate_stack_guard_pages()) {
2524 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2525 _stack_guard_state = stack_guard_unused;
2526 } else {
2527 warning("Attempt to deallocate stack guard pages failed.");
2528 }
2529 } else {
2530 if (_stack_guard_state == stack_guard_unused) return;
2531 if (os::unguard_memory((char *) low_addr, len)) {
2532 _stack_guard_state = stack_guard_unused;
2533 } else {
2534 warning("Attempt to unprotect stack guard pages failed.");
2535 }
2536 }
2537 }
2538
2539 void JavaThread::enable_stack_reserved_zone() {
2540 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2541 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2542
2543 // The base notation is from the stacks point of view, growing downward.
2544 // We need to adjust it to work correctly with guard_memory()
2545 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2546
2547 guarantee(base < stack_base(),"Error calculating stack reserved zone");
2548 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
2549
2550 if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
2551 _stack_guard_state = stack_guard_enabled;
2552 } else {
2553 warning("Attempt to guard stack reserved zone failed.");
2554 }
2555 enable_register_stack_guard();
2556 }
2557
2558 void JavaThread::disable_stack_reserved_zone() {
2559 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2560 assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled");
2561
2562 // Simply return if called for a thread that does not use guard pages.
2563 if (_stack_guard_state == stack_guard_unused) return;
2564
2565 // The base notation is from the stacks point of view, growing downward.
2566 // We need to adjust it to work correctly with guard_memory()
2567 address base = stack_reserved_zone_base() - stack_reserved_zone_size();
2568
2569 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
2570 _stack_guard_state = stack_guard_reserved_disabled;
2571 } else {
2572 warning("Attempt to unguard stack reserved zone failed.");
2573 }
2574 disable_register_stack_guard();
2575 }
2576
2577 void JavaThread::enable_stack_yellow_zone() {
2578 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2579 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2580
2581 // The base notation is from the stacks point of view, growing downward.
2582 // We need to adjust it to work correctly with guard_memory()
2583 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2584
2585 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2586 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2587
2588 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2589 _stack_guard_state = stack_guard_enabled;
2590 } else {
2591 warning("Attempt to guard stack yellow zone failed.");
2592 }
2593 enable_register_stack_guard();
2594 }
2595
2596 void JavaThread::disable_stack_yellow_zone() {
2597 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2598 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2599
2600 // Simply return if called for a thread that does not use guard pages.
2601 if (_stack_guard_state == stack_guard_unused) return;
2602
2603 // The base notation is from the stacks point of view, growing downward.
2604 // We need to adjust it to work correctly with guard_memory()
2605 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2606
2607 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2608 _stack_guard_state = stack_guard_yellow_disabled;
2609 } else {
2610 warning("Attempt to unguard stack yellow zone failed.");
2611 }
2612 disable_register_stack_guard();
2613 }
2614
2615 void JavaThread::enable_stack_red_zone() {
2616 // The base notation is from the stacks point of view, growing downward.
2617 // We need to adjust it to work correctly with guard_memory()
2618 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2619 address base = stack_red_zone_base() - stack_red_zone_size();
2620
2621 guarantee(base < stack_base(), "Error calculating stack red zone");
2622 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2623
2624 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2625 warning("Attempt to guard stack red zone failed.");
2626 }
2627 }
2628
2629 void JavaThread::disable_stack_red_zone() {
2630 // The base notation is from the stacks point of view, growing downward.
2631 // We need to adjust it to work correctly with guard_memory()
2632 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2633 address base = stack_red_zone_base() - stack_red_zone_size();
2634 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2635 warning("Attempt to unguard stack red zone failed.");
2636 }
2637 }
2638
2639 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2640 // ignore is there is no stack
2641 if (!has_last_Java_frame()) return;
2642 // traverse the stack frames. Starts from top frame.
2643 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2644 frame* fr = fst.current();
2645 f(fr, fst.register_map());
2646 }
2647 }
2648
2649
2650 #ifndef PRODUCT
2651 // Deoptimization
2652 // Function for testing deoptimization
2653 void JavaThread::deoptimize() {
2654 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2655 StackFrameStream fst(this, UseBiasedLocking);
2656 bool deopt = false; // Dump stack only if a deopt actually happens.
2657 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2658 // Iterate over all frames in the thread and deoptimize
2659 for (; !fst.is_done(); fst.next()) {
2660 if (fst.current()->can_be_deoptimized()) {
2661
2662 if (only_at) {
2663 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2664 // consists of comma or carriage return separated numbers so
2665 // search for the current bci in that string.
2666 address pc = fst.current()->pc();
2667 nmethod* nm = (nmethod*) fst.current()->cb();
2668 ScopeDesc* sd = nm->scope_desc_at(pc);
2669 char buffer[8];
2670 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2671 size_t len = strlen(buffer);
2672 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2673 while (found != NULL) {
2674 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2675 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2676 // Check that the bci found is bracketed by terminators.
2677 break;
2678 }
2679 found = strstr(found + 1, buffer);
2680 }
2681 if (!found) {
2682 continue;
2683 }
2684 }
2685
2686 if (DebugDeoptimization && !deopt) {
2687 deopt = true; // One-time only print before deopt
2688 tty->print_cr("[BEFORE Deoptimization]");
2689 trace_frames();
2690 trace_stack();
2691 }
2692 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2693 }
2694 }
2695
2696 if (DebugDeoptimization && deopt) {
2697 tty->print_cr("[AFTER Deoptimization]");
2698 trace_frames();
2699 }
2700 }
2701
2702
2703 // Make zombies
2704 void JavaThread::make_zombies() {
2705 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2706 if (fst.current()->can_be_deoptimized()) {
2707 // it is a Java nmethod
2708 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2709 nm->make_not_entrant();
2710 }
2711 }
2712 }
2713 #endif // PRODUCT
2714
2715
2716 void JavaThread::deoptimized_wrt_marked_nmethods() {
2717 if (!has_last_Java_frame()) return;
2718 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2719 StackFrameStream fst(this, UseBiasedLocking);
2720 for (; !fst.is_done(); fst.next()) {
2721 if (fst.current()->should_be_deoptimized()) {
2722 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2723 }
2724 }
2725 }
2726
2727
2728 // If the caller is a NamedThread, then remember, in the current scope,
2729 // the given JavaThread in its _processed_thread field.
2730 class RememberProcessedThread: public StackObj {
2731 NamedThread* _cur_thr;
2732 public:
2733 RememberProcessedThread(JavaThread* jthr) {
2734 Thread* thread = Thread::current();
2735 if (thread->is_Named_thread()) {
2736 _cur_thr = (NamedThread *)thread;
2737 _cur_thr->set_processed_thread(jthr);
2738 } else {
2739 _cur_thr = NULL;
2740 }
2741 }
2742
2743 ~RememberProcessedThread() {
2744 if (_cur_thr) {
2745 _cur_thr->set_processed_thread(NULL);
2746 }
2747 }
2748 };
2749
2750 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2751 // Verify that the deferred card marks have been flushed.
2752 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2753
2754 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2755 // since there may be more than one thread using each ThreadProfiler.
2756
2757 // Traverse the GCHandles
2758 Thread::oops_do(f, cld_f, cf);
2759
2760 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);)
2761
2762 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2763 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2764
2765 if (has_last_Java_frame()) {
2766 // Record JavaThread to GC thread
2767 RememberProcessedThread rpt(this);
2768
2769 // Traverse the privileged stack
2770 if (_privileged_stack_top != NULL) {
2771 _privileged_stack_top->oops_do(f);
2772 }
2773
2774 // traverse the registered growable array
2775 if (_array_for_gc != NULL) {
2776 for (int index = 0; index < _array_for_gc->length(); index++) {
2777 f->do_oop(_array_for_gc->adr_at(index));
2778 }
2779 }
2780
2781 // Traverse the monitor chunks
2782 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2783 chunk->oops_do(f);
2784 }
2785
2786 // Traverse the execution stack
2787 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2788 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2789 }
2790 }
2791
2792 // callee_target is never live across a gc point so NULL it here should
2793 // it still contain a methdOop.
2794
2795 set_callee_target(NULL);
2796
2797 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2798 // If we have deferred set_locals there might be oops waiting to be
2799 // written
2800 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2801 if (list != NULL) {
2802 for (int i = 0; i < list->length(); i++) {
2803 list->at(i)->oops_do(f);
2804 }
2805 }
2806
2807 // Traverse instance variables at the end since the GC may be moving things
2808 // around using this function
2809 f->do_oop((oop*) &_threadObj);
2810 f->do_oop((oop*) &_vm_result);
2811 f->do_oop((oop*) &_exception_oop);
2812 f->do_oop((oop*) &_pending_async_exception);
2813
2814 if (jvmti_thread_state() != NULL) {
2815 jvmti_thread_state()->oops_do(f);
2816 }
2817 }
2818
2819 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2820 Thread::nmethods_do(cf); // (super method is a no-op)
2821
2822 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2823 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2824
2825 if (has_last_Java_frame()) {
2826 // Traverse the execution stack
2827 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2828 fst.current()->nmethods_do(cf);
2829 }
2830 }
2831 }
2832
2833 void JavaThread::metadata_do(void f(Metadata*)) {
2834 if (has_last_Java_frame()) {
2835 // Traverse the execution stack to call f() on the methods in the stack
2836 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2837 fst.current()->metadata_do(f);
2838 }
2839 } else if (is_Compiler_thread()) {
2840 // need to walk ciMetadata in current compile tasks to keep alive.
2841 CompilerThread* ct = (CompilerThread*)this;
2842 if (ct->env() != NULL) {
2843 ct->env()->metadata_do(f);
2844 }
2845 if (ct->task() != NULL) {
2846 ct->task()->metadata_do(f);
2847 }
2848 }
2849 }
2850
2851 // Printing
2852 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2853 switch (_thread_state) {
2854 case _thread_uninitialized: return "_thread_uninitialized";
2855 case _thread_new: return "_thread_new";
2856 case _thread_new_trans: return "_thread_new_trans";
2857 case _thread_in_native: return "_thread_in_native";
2858 case _thread_in_native_trans: return "_thread_in_native_trans";
2859 case _thread_in_vm: return "_thread_in_vm";
2860 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2861 case _thread_in_Java: return "_thread_in_Java";
2862 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2863 case _thread_blocked: return "_thread_blocked";
2864 case _thread_blocked_trans: return "_thread_blocked_trans";
2865 default: return "unknown thread state";
2866 }
2867 }
2868
2869 #ifndef PRODUCT
2870 void JavaThread::print_thread_state_on(outputStream *st) const {
2871 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2872 };
2873 void JavaThread::print_thread_state() const {
2874 print_thread_state_on(tty);
2875 }
2876 #endif // PRODUCT
2877
2878 // Called by Threads::print() for VM_PrintThreads operation
2879 void JavaThread::print_on(outputStream *st) const {
2880 st->print("\"%s\" ", get_thread_name());
2881 oop thread_oop = threadObj();
2882 if (thread_oop != NULL) {
2883 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2884 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2885 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2886 }
2887 Thread::print_on(st);
2888 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2889 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2890 if (thread_oop != NULL) {
2891 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2892 }
2893 #ifndef PRODUCT
2894 print_thread_state_on(st);
2895 _safepoint_state->print_on(st);
2896 #endif // PRODUCT
2897 }
2898
2899 // Called by fatal error handler. The difference between this and
2900 // JavaThread::print() is that we can't grab lock or allocate memory.
2901 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2902 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2903 oop thread_obj = threadObj();
2904 if (thread_obj != NULL) {
2905 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2906 }
2907 st->print(" [");
2908 st->print("%s", _get_thread_state_name(_thread_state));
2909 if (osthread()) {
2910 st->print(", id=%d", osthread()->thread_id());
2911 }
2912 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2913 p2i(_stack_base - _stack_size), p2i(_stack_base));
2914 st->print("]");
2915 return;
2916 }
2917
2918 // Verification
2919
2920 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2921
2922 void JavaThread::verify() {
2923 // Verify oops in the thread.
2924 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2925
2926 // Verify the stack frames.
2927 frames_do(frame_verify);
2928 }
2929
2930 // CR 6300358 (sub-CR 2137150)
2931 // Most callers of this method assume that it can't return NULL but a
2932 // thread may not have a name whilst it is in the process of attaching to
2933 // the VM - see CR 6412693, and there are places where a JavaThread can be
2934 // seen prior to having it's threadObj set (eg JNI attaching threads and
2935 // if vm exit occurs during initialization). These cases can all be accounted
2936 // for such that this method never returns NULL.
2937 const char* JavaThread::get_thread_name() const {
2938 #ifdef ASSERT
2939 // early safepoints can hit while current thread does not yet have TLS
2940 if (!SafepointSynchronize::is_at_safepoint()) {
2941 Thread *cur = Thread::current();
2942 if (!(cur->is_Java_thread() && cur == this)) {
2943 // Current JavaThreads are allowed to get their own name without
2944 // the Threads_lock.
2945 assert_locked_or_safepoint(Threads_lock);
2946 }
2947 }
2948 #endif // ASSERT
2949 return get_thread_name_string();
2950 }
2951
2952 // Returns a non-NULL representation of this thread's name, or a suitable
2953 // descriptive string if there is no set name
2954 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2955 const char* name_str;
2956 oop thread_obj = threadObj();
2957 if (thread_obj != NULL) {
2958 oop name = java_lang_Thread::name(thread_obj);
2959 if (name != NULL) {
2960 if (buf == NULL) {
2961 name_str = java_lang_String::as_utf8_string(name);
2962 } else {
2963 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2964 }
2965 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2966 name_str = "<no-name - thread is attaching>";
2967 } else {
2968 name_str = Thread::name();
2969 }
2970 } else {
2971 name_str = Thread::name();
2972 }
2973 assert(name_str != NULL, "unexpected NULL thread name");
2974 return name_str;
2975 }
2976
2977
2978 const char* JavaThread::get_threadgroup_name() const {
2979 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2980 oop thread_obj = threadObj();
2981 if (thread_obj != NULL) {
2982 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2983 if (thread_group != NULL) {
2984 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2985 // ThreadGroup.name can be null
2986 if (name != NULL) {
2987 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2988 return str;
2989 }
2990 }
2991 }
2992 return NULL;
2993 }
2994
2995 const char* JavaThread::get_parent_name() const {
2996 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2997 oop thread_obj = threadObj();
2998 if (thread_obj != NULL) {
2999 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
3000 if (thread_group != NULL) {
3001 oop parent = java_lang_ThreadGroup::parent(thread_group);
3002 if (parent != NULL) {
3003 typeArrayOop name = java_lang_ThreadGroup::name(parent);
3004 // ThreadGroup.name can be null
3005 if (name != NULL) {
3006 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
3007 return str;
3008 }
3009 }
3010 }
3011 }
3012 return NULL;
3013 }
3014
3015 ThreadPriority JavaThread::java_priority() const {
3016 oop thr_oop = threadObj();
3017 if (thr_oop == NULL) return NormPriority; // Bootstrapping
3018 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
3019 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
3020 return priority;
3021 }
3022
3023 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
3024
3025 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3026 // Link Java Thread object <-> C++ Thread
3027
3028 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3029 // and put it into a new Handle. The Handle "thread_oop" can then
3030 // be used to pass the C++ thread object to other methods.
3031
3032 // Set the Java level thread object (jthread) field of the
3033 // new thread (a JavaThread *) to C++ thread object using the
3034 // "thread_oop" handle.
3035
3036 // Set the thread field (a JavaThread *) of the
3037 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3038
3039 Handle thread_oop(Thread::current(),
3040 JNIHandles::resolve_non_null(jni_thread));
3041 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3042 "must be initialized");
3043 set_threadObj(thread_oop());
3044 java_lang_Thread::set_thread(thread_oop(), this);
3045
3046 if (prio == NoPriority) {
3047 prio = java_lang_Thread::priority(thread_oop());
3048 assert(prio != NoPriority, "A valid priority should be present");
3049 }
3050
3051 // Push the Java priority down to the native thread; needs Threads_lock
3052 Thread::set_priority(this, prio);
3053
3054 prepare_ext();
3055
3056 // Add the new thread to the Threads list and set it in motion.
3057 // We must have threads lock in order to call Threads::add.
3058 // It is crucial that we do not block before the thread is
3059 // added to the Threads list for if a GC happens, then the java_thread oop
3060 // will not be visited by GC.
3061 Threads::add(this);
3062 }
3063
3064 oop JavaThread::current_park_blocker() {
3065 // Support for JSR-166 locks
3066 oop thread_oop = threadObj();
3067 if (thread_oop != NULL &&
3068 JDK_Version::current().supports_thread_park_blocker()) {
3069 return java_lang_Thread::park_blocker(thread_oop);
3070 }
3071 return NULL;
3072 }
3073
3074
3075 void JavaThread::print_stack_on(outputStream* st) {
3076 if (!has_last_Java_frame()) return;
3077 ResourceMark rm;
3078 HandleMark hm;
3079
3080 RegisterMap reg_map(this);
3081 vframe* start_vf = last_java_vframe(®_map);
3082 int count = 0;
3083 for (vframe* f = start_vf; f; f = f->sender()) {
3084 if (f->is_java_frame()) {
3085 javaVFrame* jvf = javaVFrame::cast(f);
3086 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3087
3088 // Print out lock information
3089 if (JavaMonitorsInStackTrace) {
3090 jvf->print_lock_info_on(st, count);
3091 }
3092 } else {
3093 // Ignore non-Java frames
3094 }
3095
3096 // Bail-out case for too deep stacks
3097 count++;
3098 if (MaxJavaStackTraceDepth == count) return;
3099 }
3100 }
3101
3102
3103 // JVMTI PopFrame support
3104 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3105 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3106 if (in_bytes(size_in_bytes) != 0) {
3107 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3108 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3109 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3110 }
3111 }
3112
3113 void* JavaThread::popframe_preserved_args() {
3114 return _popframe_preserved_args;
3115 }
3116
3117 ByteSize JavaThread::popframe_preserved_args_size() {
3118 return in_ByteSize(_popframe_preserved_args_size);
3119 }
3120
3121 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3122 int sz = in_bytes(popframe_preserved_args_size());
3123 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3124 return in_WordSize(sz / wordSize);
3125 }
3126
3127 void JavaThread::popframe_free_preserved_args() {
3128 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3129 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3130 _popframe_preserved_args = NULL;
3131 _popframe_preserved_args_size = 0;
3132 }
3133
3134 #ifndef PRODUCT
3135
3136 void JavaThread::trace_frames() {
3137 tty->print_cr("[Describe stack]");
3138 int frame_no = 1;
3139 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3140 tty->print(" %d. ", frame_no++);
3141 fst.current()->print_value_on(tty, this);
3142 tty->cr();
3143 }
3144 }
3145
3146 class PrintAndVerifyOopClosure: public OopClosure {
3147 protected:
3148 template <class T> inline void do_oop_work(T* p) {
3149 oop obj = oopDesc::load_decode_heap_oop(p);
3150 if (obj == NULL) return;
3151 tty->print(INTPTR_FORMAT ": ", p2i(p));
3152 if (obj->is_oop_or_null()) {
3153 if (obj->is_objArray()) {
3154 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
3155 } else {
3156 obj->print();
3157 }
3158 } else {
3159 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
3160 }
3161 tty->cr();
3162 }
3163 public:
3164 virtual void do_oop(oop* p) { do_oop_work(p); }
3165 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3166 };
3167
3168
3169 static void oops_print(frame* f, const RegisterMap *map) {
3170 PrintAndVerifyOopClosure print;
3171 f->print_value();
3172 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3173 }
3174
3175 // Print our all the locations that contain oops and whether they are
3176 // valid or not. This useful when trying to find the oldest frame
3177 // where an oop has gone bad since the frame walk is from youngest to
3178 // oldest.
3179 void JavaThread::trace_oops() {
3180 tty->print_cr("[Trace oops]");
3181 frames_do(oops_print);
3182 }
3183
3184
3185 #ifdef ASSERT
3186 // Print or validate the layout of stack frames
3187 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3188 ResourceMark rm;
3189 PRESERVE_EXCEPTION_MARK;
3190 FrameValues values;
3191 int frame_no = 0;
3192 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3193 fst.current()->describe(values, ++frame_no);
3194 if (depth == frame_no) break;
3195 }
3196 if (validate_only) {
3197 values.validate();
3198 } else {
3199 tty->print_cr("[Describe stack layout]");
3200 values.print(this);
3201 }
3202 }
3203 #endif
3204
3205 void JavaThread::trace_stack_from(vframe* start_vf) {
3206 ResourceMark rm;
3207 int vframe_no = 1;
3208 for (vframe* f = start_vf; f; f = f->sender()) {
3209 if (f->is_java_frame()) {
3210 javaVFrame::cast(f)->print_activation(vframe_no++);
3211 } else {
3212 f->print();
3213 }
3214 if (vframe_no > StackPrintLimit) {
3215 tty->print_cr("...<more frames>...");
3216 return;
3217 }
3218 }
3219 }
3220
3221
3222 void JavaThread::trace_stack() {
3223 if (!has_last_Java_frame()) return;
3224 ResourceMark rm;
3225 HandleMark hm;
3226 RegisterMap reg_map(this);
3227 trace_stack_from(last_java_vframe(®_map));
3228 }
3229
3230
3231 #endif // PRODUCT
3232
3233
3234 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3235 assert(reg_map != NULL, "a map must be given");
3236 frame f = last_frame();
3237 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3238 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3239 }
3240 return NULL;
3241 }
3242
3243
3244 Klass* JavaThread::security_get_caller_class(int depth) {
3245 vframeStream vfst(this);
3246 vfst.security_get_caller_frame(depth);
3247 if (!vfst.at_end()) {
3248 return vfst.method()->method_holder();
3249 }
3250 return NULL;
3251 }
3252
3253 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3254 assert(thread->is_Compiler_thread(), "must be compiler thread");
3255 CompileBroker::compiler_thread_loop();
3256 }
3257
3258 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3259 NMethodSweeper::sweeper_loop();
3260 }
3261
3262 // Create a CompilerThread
3263 CompilerThread::CompilerThread(CompileQueue* queue,
3264 CompilerCounters* counters)
3265 : JavaThread(&compiler_thread_entry) {
3266 _env = NULL;
3267 _log = NULL;
3268 _task = NULL;
3269 _queue = queue;
3270 _counters = counters;
3271 _buffer_blob = NULL;
3272 _compiler = NULL;
3273
3274 #ifndef PRODUCT
3275 _ideal_graph_printer = NULL;
3276 #endif
3277 }
3278
3279 bool CompilerThread::can_call_java() const {
3280 return _compiler != NULL && _compiler->is_jvmci();
3281 }
3282
3283 // Create sweeper thread
3284 CodeCacheSweeperThread::CodeCacheSweeperThread()
3285 : JavaThread(&sweeper_thread_entry) {
3286 _scanned_nmethod = NULL;
3287 }
3288 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3289 JavaThread::oops_do(f, cld_f, cf);
3290 if (_scanned_nmethod != NULL && cf != NULL) {
3291 // Safepoints can occur when the sweeper is scanning an nmethod so
3292 // process it here to make sure it isn't unloaded in the middle of
3293 // a scan.
3294 cf->do_code_blob(_scanned_nmethod);
3295 }
3296 }
3297
3298
3299 // ======= Threads ========
3300
3301 // The Threads class links together all active threads, and provides
3302 // operations over all threads. It is protected by its own Mutex
3303 // lock, which is also used in other contexts to protect thread
3304 // operations from having the thread being operated on from exiting
3305 // and going away unexpectedly (e.g., safepoint synchronization)
3306
3307 JavaThread* Threads::_thread_list = NULL;
3308 int Threads::_number_of_threads = 0;
3309 int Threads::_number_of_non_daemon_threads = 0;
3310 int Threads::_return_code = 0;
3311 int Threads::_thread_claim_parity = 0;
3312 size_t JavaThread::_stack_size_at_create = 0;
3313 #ifdef ASSERT
3314 bool Threads::_vm_complete = false;
3315 #endif
3316
3317 // All JavaThreads
3318 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3319
3320 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3321 void Threads::threads_do(ThreadClosure* tc) {
3322 assert_locked_or_safepoint(Threads_lock);
3323 // ALL_JAVA_THREADS iterates through all JavaThreads
3324 ALL_JAVA_THREADS(p) {
3325 tc->do_thread(p);
3326 }
3327 // Someday we could have a table or list of all non-JavaThreads.
3328 // For now, just manually iterate through them.
3329 tc->do_thread(VMThread::vm_thread());
3330 Universe::heap()->gc_threads_do(tc);
3331 WatcherThread *wt = WatcherThread::watcher_thread();
3332 // Strictly speaking, the following NULL check isn't sufficient to make sure
3333 // the data for WatcherThread is still valid upon being examined. However,
3334 // considering that WatchThread terminates when the VM is on the way to
3335 // exit at safepoint, the chance of the above is extremely small. The right
3336 // way to prevent termination of WatcherThread would be to acquire
3337 // Terminator_lock, but we can't do that without violating the lock rank
3338 // checking in some cases.
3339 if (wt != NULL) {
3340 tc->do_thread(wt);
3341 }
3342
3343 // If CompilerThreads ever become non-JavaThreads, add them here
3344 }
3345
3346 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3347 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3348
3349 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3350 create_vm_init_libraries();
3351 }
3352
3353 initialize_class(vmSymbols::java_lang_String(), CHECK);
3354
3355 // Initialize java_lang.System (needed before creating the thread)
3356 initialize_class(vmSymbols::java_lang_System(), CHECK);
3357 // The VM creates & returns objects of this class. Make sure it's initialized.
3358 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3359 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3360 Handle thread_group = create_initial_thread_group(CHECK);
3361 Universe::set_main_thread_group(thread_group());
3362 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3363 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3364 main_thread->set_threadObj(thread_object);
3365 // Set thread status to running since main thread has
3366 // been started and running.
3367 java_lang_Thread::set_thread_status(thread_object,
3368 java_lang_Thread::RUNNABLE);
3369
3370 // The VM preresolves methods to these classes. Make sure that they get initialized
3371 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3372 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3373 call_initializeSystemClass(CHECK);
3374
3375 // get the Java runtime name after java.lang.System is initialized
3376 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3377 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3378
3379 // an instance of OutOfMemory exception has been allocated earlier
3380 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3381 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3382 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3383 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3384 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3385 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3386 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3387 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3388 }
3389
3390 void Threads::initialize_jsr292_core_classes(TRAPS) {
3391 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3392 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3393 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3394 }
3395
3396 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3397 extern void JDK_Version_init();
3398
3399 // Preinitialize version info.
3400 VM_Version::early_initialize();
3401
3402 // Check version
3403 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3404
3405 // Initialize the output stream module
3406 ostream_init();
3407
3408 // Process java launcher properties.
3409 Arguments::process_sun_java_launcher_properties(args);
3410
3411 // Initialize the os module before using TLS
3412 os::init();
3413
3414 // Record VM creation timing statistics
3415 TraceVmCreationTime create_vm_timer;
3416 create_vm_timer.start();
3417
3418 // Initialize system properties.
3419 Arguments::init_system_properties();
3420
3421 // So that JDK version can be used as a discriminator when parsing arguments
3422 JDK_Version_init();
3423
3424 // Update/Initialize System properties after JDK version number is known
3425 Arguments::init_version_specific_system_properties();
3426
3427 // Make sure to initialize log configuration *before* parsing arguments
3428 LogConfiguration::initialize(create_vm_timer.begin_time());
3429
3430 // Parse arguments
3431 jint parse_result = Arguments::parse(args);
3432 if (parse_result != JNI_OK) return parse_result;
3433
3434 os::init_before_ergo();
3435
3436 jint ergo_result = Arguments::apply_ergo();
3437 if (ergo_result != JNI_OK) return ergo_result;
3438
3439 // Final check of all ranges after ergonomics which may change values.
3440 if (!CommandLineFlagRangeList::check_ranges()) {
3441 return JNI_EINVAL;
3442 }
3443
3444 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3445 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3446 if (!constraint_result) {
3447 return JNI_EINVAL;
3448 }
3449
3450 if (PauseAtStartup) {
3451 os::pause();
3452 }
3453
3454 HOTSPOT_VM_INIT_BEGIN();
3455
3456 // Timing (must come after argument parsing)
3457 TraceTime timer("Create VM", TraceStartupTime);
3458
3459 // Initialize the os module after parsing the args
3460 jint os_init_2_result = os::init_2();
3461 if (os_init_2_result != JNI_OK) return os_init_2_result;
3462
3463 jint adjust_after_os_result = Arguments::adjust_after_os();
3464 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3465
3466 // initialize TLS
3467 ThreadLocalStorage::init();
3468
3469 // Initialize output stream logging
3470 ostream_init_log();
3471
3472 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3473 // Must be before create_vm_init_agents()
3474 if (Arguments::init_libraries_at_startup()) {
3475 convert_vm_init_libraries_to_agents();
3476 }
3477
3478 // Launch -agentlib/-agentpath and converted -Xrun agents
3479 if (Arguments::init_agents_at_startup()) {
3480 create_vm_init_agents();
3481 }
3482
3483 // Initialize Threads state
3484 _thread_list = NULL;
3485 _number_of_threads = 0;
3486 _number_of_non_daemon_threads = 0;
3487
3488 // Initialize global data structures and create system classes in heap
3489 vm_init_globals();
3490
3491 #if INCLUDE_JVMCI
3492 if (JVMCICounterSize > 0) {
3493 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
3494 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
3495 } else {
3496 JavaThread::_jvmci_old_thread_counters = NULL;
3497 }
3498 #endif // INCLUDE_JVMCI
3499
3500 // Attach the main thread to this os thread
3501 JavaThread* main_thread = new JavaThread();
3502 main_thread->set_thread_state(_thread_in_vm);
3503 // must do this before set_active_handles and initialize_thread_local_storage
3504 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3505 // change the stack size recorded here to one based on the java thread
3506 // stacksize. This adjusted size is what is used to figure the placement
3507 // of the guard pages.
3508 main_thread->record_stack_base_and_size();
3509 main_thread->initialize_thread_local_storage();
3510
3511 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3512
3513 if (!main_thread->set_as_starting_thread()) {
3514 vm_shutdown_during_initialization(
3515 "Failed necessary internal allocation. Out of swap space");
3516 delete main_thread;
3517 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3518 return JNI_ENOMEM;
3519 }
3520
3521 // Enable guard page *after* os::create_main_thread(), otherwise it would
3522 // crash Linux VM, see notes in os_linux.cpp.
3523 main_thread->create_stack_guard_pages();
3524
3525 // Initialize Java-Level synchronization subsystem
3526 ObjectMonitor::Initialize();
3527
3528 // Initialize global modules
3529 jint status = init_globals();
3530 if (status != JNI_OK) {
3531 delete main_thread;
3532 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3533 return status;
3534 }
3535
3536 // Should be done after the heap is fully created
3537 main_thread->cache_global_variables();
3538
3539 HandleMark hm;
3540
3541 { MutexLocker mu(Threads_lock);
3542 Threads::add(main_thread);
3543 }
3544
3545 // Any JVMTI raw monitors entered in onload will transition into
3546 // real raw monitor. VM is setup enough here for raw monitor enter.
3547 JvmtiExport::transition_pending_onload_raw_monitors();
3548
3549 // Create the VMThread
3550 { TraceTime timer("Start VMThread", TraceStartupTime);
3551 VMThread::create();
3552 Thread* vmthread = VMThread::vm_thread();
3553
3554 if (!os::create_thread(vmthread, os::vm_thread)) {
3555 vm_exit_during_initialization("Cannot create VM thread. "
3556 "Out of system resources.");
3557 }
3558
3559 // Wait for the VM thread to become ready, and VMThread::run to initialize
3560 // Monitors can have spurious returns, must always check another state flag
3561 {
3562 MutexLocker ml(Notify_lock);
3563 os::start_thread(vmthread);
3564 while (vmthread->active_handles() == NULL) {
3565 Notify_lock->wait();
3566 }
3567 }
3568 }
3569
3570 assert(Universe::is_fully_initialized(), "not initialized");
3571 if (VerifyDuringStartup) {
3572 // Make sure we're starting with a clean slate.
3573 VM_Verify verify_op;
3574 VMThread::execute(&verify_op);
3575 }
3576
3577 Thread* THREAD = Thread::current();
3578
3579 // At this point, the Universe is initialized, but we have not executed
3580 // any byte code. Now is a good time (the only time) to dump out the
3581 // internal state of the JVM for sharing.
3582 if (DumpSharedSpaces) {
3583 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3584 ShouldNotReachHere();
3585 }
3586
3587 // Always call even when there are not JVMTI environments yet, since environments
3588 // may be attached late and JVMTI must track phases of VM execution
3589 JvmtiExport::enter_start_phase();
3590
3591 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3592 JvmtiExport::post_vm_start();
3593
3594 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3595
3596 // We need this for ClassDataSharing - the initial vm.info property is set
3597 // with the default value of CDS "sharing" which may be reset through
3598 // command line options.
3599 reset_vm_info_property(CHECK_JNI_ERR);
3600
3601 quicken_jni_functions();
3602
3603 // Must be run after init_ft which initializes ft_enabled
3604 if (TRACE_INITIALIZE() != JNI_OK) {
3605 vm_exit_during_initialization("Failed to initialize tracing backend");
3606 }
3607
3608 // Set flag that basic initialization has completed. Used by exceptions and various
3609 // debug stuff, that does not work until all basic classes have been initialized.
3610 set_init_completed();
3611
3612 LogConfiguration::post_initialize();
3613 Metaspace::post_initialize();
3614
3615 HOTSPOT_VM_INIT_END();
3616
3617 // record VM initialization completion time
3618 #if INCLUDE_MANAGEMENT
3619 Management::record_vm_init_completed();
3620 #endif // INCLUDE_MANAGEMENT
3621
3622 // Compute system loader. Note that this has to occur after set_init_completed, since
3623 // valid exceptions may be thrown in the process.
3624 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3625 // set_init_completed has just been called, causing exceptions not to be shortcut
3626 // anymore. We call vm_exit_during_initialization directly instead.
3627 SystemDictionary::compute_java_system_loader(CHECK_(JNI_ERR));
3628
3629 #if INCLUDE_ALL_GCS
3630 // Support for ConcurrentMarkSweep. This should be cleaned up
3631 // and better encapsulated. The ugly nested if test would go away
3632 // once things are properly refactored. XXX YSR
3633 if (UseConcMarkSweepGC || UseG1GC) {
3634 if (UseConcMarkSweepGC) {
3635 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3636 } else {
3637 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3638 }
3639 }
3640 #endif // INCLUDE_ALL_GCS
3641
3642 // Always call even when there are not JVMTI environments yet, since environments
3643 // may be attached late and JVMTI must track phases of VM execution
3644 JvmtiExport::enter_live_phase();
3645
3646 // Signal Dispatcher needs to be started before VMInit event is posted
3647 os::signal_init();
3648
3649 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3650 if (!DisableAttachMechanism) {
3651 AttachListener::vm_start();
3652 if (StartAttachListener || AttachListener::init_at_startup()) {
3653 AttachListener::init();
3654 }
3655 }
3656
3657 // Launch -Xrun agents
3658 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3659 // back-end can launch with -Xdebug -Xrunjdwp.
3660 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3661 create_vm_init_libraries();
3662 }
3663
3664 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3665 JvmtiExport::post_vm_initialized();
3666
3667 if (TRACE_START() != JNI_OK) {
3668 vm_exit_during_initialization("Failed to start tracing backend.");
3669 }
3670
3671 if (CleanChunkPoolAsync) {
3672 Chunk::start_chunk_pool_cleaner_task();
3673 }
3674
3675 #if INCLUDE_JVMCI
3676 if (EnableJVMCI) {
3677 const char* jvmciCompiler = Arguments::PropertyList_get_value(Arguments::system_properties(), "jvmci.compiler");
3678 if (jvmciCompiler != NULL) {
3679 JVMCIRuntime::save_compiler(jvmciCompiler);
3680 }
3681 }
3682 #endif // INCLUDE_JVMCI
3683
3684 // initialize compiler(s)
3685 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) || INCLUDE_JVMCI
3686 CompileBroker::compilation_init();
3687 #endif
3688
3689 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3690 // It is done after compilers are initialized, because otherwise compilations of
3691 // signature polymorphic MH intrinsics can be missed
3692 // (see SystemDictionary::find_method_handle_intrinsic).
3693 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3694
3695 #if INCLUDE_MANAGEMENT
3696 Management::initialize(THREAD);
3697
3698 if (HAS_PENDING_EXCEPTION) {
3699 // management agent fails to start possibly due to
3700 // configuration problem and is responsible for printing
3701 // stack trace if appropriate. Simply exit VM.
3702 vm_exit(1);
3703 }
3704 #endif // INCLUDE_MANAGEMENT
3705
3706 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3707 if (MemProfiling) MemProfiler::engage();
3708 StatSampler::engage();
3709 if (CheckJNICalls) JniPeriodicChecker::engage();
3710
3711 BiasedLocking::init();
3712
3713 #if INCLUDE_RTM_OPT
3714 RTMLockingCounters::init();
3715 #endif
3716
3717 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3718 call_postVMInitHook(THREAD);
3719 // The Java side of PostVMInitHook.run must deal with all
3720 // exceptions and provide means of diagnosis.
3721 if (HAS_PENDING_EXCEPTION) {
3722 CLEAR_PENDING_EXCEPTION;
3723 }
3724 }
3725
3726 {
3727 MutexLocker ml(PeriodicTask_lock);
3728 // Make sure the WatcherThread can be started by WatcherThread::start()
3729 // or by dynamic enrollment.
3730 WatcherThread::make_startable();
3731 // Start up the WatcherThread if there are any periodic tasks
3732 // NOTE: All PeriodicTasks should be registered by now. If they
3733 // aren't, late joiners might appear to start slowly (we might
3734 // take a while to process their first tick).
3735 if (PeriodicTask::num_tasks() > 0) {
3736 WatcherThread::start();
3737 }
3738 }
3739
3740 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM);
3741
3742 create_vm_timer.end();
3743 #ifdef ASSERT
3744 _vm_complete = true;
3745 #endif
3746 return JNI_OK;
3747 }
3748
3749 // type for the Agent_OnLoad and JVM_OnLoad entry points
3750 extern "C" {
3751 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3752 }
3753 // Find a command line agent library and return its entry point for
3754 // -agentlib: -agentpath: -Xrun
3755 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3756 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3757 const char *on_load_symbols[],
3758 size_t num_symbol_entries) {
3759 OnLoadEntry_t on_load_entry = NULL;
3760 void *library = NULL;
3761
3762 if (!agent->valid()) {
3763 char buffer[JVM_MAXPATHLEN];
3764 char ebuf[1024] = "";
3765 const char *name = agent->name();
3766 const char *msg = "Could not find agent library ";
3767
3768 // First check to see if agent is statically linked into executable
3769 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3770 library = agent->os_lib();
3771 } else if (agent->is_absolute_path()) {
3772 library = os::dll_load(name, ebuf, sizeof ebuf);
3773 if (library == NULL) {
3774 const char *sub_msg = " in absolute path, with error: ";
3775 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3776 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3777 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3778 // If we can't find the agent, exit.
3779 vm_exit_during_initialization(buf, NULL);
3780 FREE_C_HEAP_ARRAY(char, buf);
3781 }
3782 } else {
3783 // Try to load the agent from the standard dll directory
3784 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3785 name)) {
3786 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3787 }
3788 if (library == NULL) { // Try the local directory
3789 char ns[1] = {0};
3790 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3791 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3792 }
3793 if (library == NULL) {
3794 const char *sub_msg = " on the library path, with error: ";
3795 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3796 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3797 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3798 // If we can't find the agent, exit.
3799 vm_exit_during_initialization(buf, NULL);
3800 FREE_C_HEAP_ARRAY(char, buf);
3801 }
3802 }
3803 }
3804 agent->set_os_lib(library);
3805 agent->set_valid();
3806 }
3807
3808 // Find the OnLoad function.
3809 on_load_entry =
3810 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3811 false,
3812 on_load_symbols,
3813 num_symbol_entries));
3814 return on_load_entry;
3815 }
3816
3817 // Find the JVM_OnLoad entry point
3818 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3819 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3820 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3821 }
3822
3823 // Find the Agent_OnLoad entry point
3824 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3825 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3826 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3827 }
3828
3829 // For backwards compatibility with -Xrun
3830 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3831 // treated like -agentpath:
3832 // Must be called before agent libraries are created
3833 void Threads::convert_vm_init_libraries_to_agents() {
3834 AgentLibrary* agent;
3835 AgentLibrary* next;
3836
3837 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3838 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3839 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3840
3841 // If there is an JVM_OnLoad function it will get called later,
3842 // otherwise see if there is an Agent_OnLoad
3843 if (on_load_entry == NULL) {
3844 on_load_entry = lookup_agent_on_load(agent);
3845 if (on_load_entry != NULL) {
3846 // switch it to the agent list -- so that Agent_OnLoad will be called,
3847 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3848 Arguments::convert_library_to_agent(agent);
3849 } else {
3850 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3851 }
3852 }
3853 }
3854 }
3855
3856 // Create agents for -agentlib: -agentpath: and converted -Xrun
3857 // Invokes Agent_OnLoad
3858 // Called very early -- before JavaThreads exist
3859 void Threads::create_vm_init_agents() {
3860 extern struct JavaVM_ main_vm;
3861 AgentLibrary* agent;
3862
3863 JvmtiExport::enter_onload_phase();
3864
3865 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3866 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3867
3868 if (on_load_entry != NULL) {
3869 // Invoke the Agent_OnLoad function
3870 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3871 if (err != JNI_OK) {
3872 vm_exit_during_initialization("agent library failed to init", agent->name());
3873 }
3874 } else {
3875 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3876 }
3877 }
3878 JvmtiExport::enter_primordial_phase();
3879 }
3880
3881 extern "C" {
3882 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3883 }
3884
3885 void Threads::shutdown_vm_agents() {
3886 // Send any Agent_OnUnload notifications
3887 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3888 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3889 extern struct JavaVM_ main_vm;
3890 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3891
3892 // Find the Agent_OnUnload function.
3893 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3894 os::find_agent_function(agent,
3895 false,
3896 on_unload_symbols,
3897 num_symbol_entries));
3898
3899 // Invoke the Agent_OnUnload function
3900 if (unload_entry != NULL) {
3901 JavaThread* thread = JavaThread::current();
3902 ThreadToNativeFromVM ttn(thread);
3903 HandleMark hm(thread);
3904 (*unload_entry)(&main_vm);
3905 }
3906 }
3907 }
3908
3909 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3910 // Invokes JVM_OnLoad
3911 void Threads::create_vm_init_libraries() {
3912 extern struct JavaVM_ main_vm;
3913 AgentLibrary* agent;
3914
3915 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3916 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3917
3918 if (on_load_entry != NULL) {
3919 // Invoke the JVM_OnLoad function
3920 JavaThread* thread = JavaThread::current();
3921 ThreadToNativeFromVM ttn(thread);
3922 HandleMark hm(thread);
3923 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3924 if (err != JNI_OK) {
3925 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3926 }
3927 } else {
3928 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3929 }
3930 }
3931 }
3932
3933 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3934 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3935
3936 JavaThread* java_thread = NULL;
3937 // Sequential search for now. Need to do better optimization later.
3938 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3939 oop tobj = thread->threadObj();
3940 if (!thread->is_exiting() &&
3941 tobj != NULL &&
3942 java_tid == java_lang_Thread::thread_id(tobj)) {
3943 java_thread = thread;
3944 break;
3945 }
3946 }
3947 return java_thread;
3948 }
3949
3950
3951 // Last thread running calls java.lang.Shutdown.shutdown()
3952 void JavaThread::invoke_shutdown_hooks() {
3953 HandleMark hm(this);
3954
3955 // We could get here with a pending exception, if so clear it now.
3956 if (this->has_pending_exception()) {
3957 this->clear_pending_exception();
3958 }
3959
3960 EXCEPTION_MARK;
3961 Klass* k =
3962 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3963 THREAD);
3964 if (k != NULL) {
3965 // SystemDictionary::resolve_or_null will return null if there was
3966 // an exception. If we cannot load the Shutdown class, just don't
3967 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3968 // and finalizers (if runFinalizersOnExit is set) won't be run.
3969 // Note that if a shutdown hook was registered or runFinalizersOnExit
3970 // was called, the Shutdown class would have already been loaded
3971 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3972 instanceKlassHandle shutdown_klass (THREAD, k);
3973 JavaValue result(T_VOID);
3974 JavaCalls::call_static(&result,
3975 shutdown_klass,
3976 vmSymbols::shutdown_method_name(),
3977 vmSymbols::void_method_signature(),
3978 THREAD);
3979 }
3980 CLEAR_PENDING_EXCEPTION;
3981 }
3982
3983 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3984 // the program falls off the end of main(). Another VM exit path is through
3985 // vm_exit() when the program calls System.exit() to return a value or when
3986 // there is a serious error in VM. The two shutdown paths are not exactly
3987 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3988 // and VM_Exit op at VM level.
3989 //
3990 // Shutdown sequence:
3991 // + Shutdown native memory tracking if it is on
3992 // + Wait until we are the last non-daemon thread to execute
3993 // <-- every thing is still working at this moment -->
3994 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3995 // shutdown hooks, run finalizers if finalization-on-exit
3996 // + Call before_exit(), prepare for VM exit
3997 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3998 // currently the only user of this mechanism is File.deleteOnExit())
3999 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
4000 // post thread end and vm death events to JVMTI,
4001 // stop signal thread
4002 // + Call JavaThread::exit(), it will:
4003 // > release JNI handle blocks, remove stack guard pages
4004 // > remove this thread from Threads list
4005 // <-- no more Java code from this thread after this point -->
4006 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
4007 // the compiler threads at safepoint
4008 // <-- do not use anything that could get blocked by Safepoint -->
4009 // + Disable tracing at JNI/JVM barriers
4010 // + Set _vm_exited flag for threads that are still running native code
4011 // + Delete this thread
4012 // + Call exit_globals()
4013 // > deletes tty
4014 // > deletes PerfMemory resources
4015 // + Return to caller
4016
4017 bool Threads::destroy_vm() {
4018 JavaThread* thread = JavaThread::current();
4019
4020 #ifdef ASSERT
4021 _vm_complete = false;
4022 #endif
4023 // Wait until we are the last non-daemon thread to execute
4024 { MutexLocker nu(Threads_lock);
4025 while (Threads::number_of_non_daemon_threads() > 1)
4026 // This wait should make safepoint checks, wait without a timeout,
4027 // and wait as a suspend-equivalent condition.
4028 //
4029 // Note: If the FlatProfiler is running and this thread is waiting
4030 // for another non-daemon thread to finish, then the FlatProfiler
4031 // is waiting for the external suspend request on this thread to
4032 // complete. wait_for_ext_suspend_completion() will eventually
4033 // timeout, but that takes time. Making this wait a suspend-
4034 // equivalent condition solves that timeout problem.
4035 //
4036 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
4037 Mutex::_as_suspend_equivalent_flag);
4038 }
4039
4040 // Hang forever on exit if we are reporting an error.
4041 if (ShowMessageBoxOnError && is_error_reported()) {
4042 os::infinite_sleep();
4043 }
4044 os::wait_for_keypress_at_exit();
4045
4046 // run Java level shutdown hooks
4047 thread->invoke_shutdown_hooks();
4048
4049 before_exit(thread);
4050
4051 thread->exit(true);
4052
4053 // Stop VM thread.
4054 {
4055 // 4945125 The vm thread comes to a safepoint during exit.
4056 // GC vm_operations can get caught at the safepoint, and the
4057 // heap is unparseable if they are caught. Grab the Heap_lock
4058 // to prevent this. The GC vm_operations will not be able to
4059 // queue until after the vm thread is dead. After this point,
4060 // we'll never emerge out of the safepoint before the VM exits.
4061
4062 MutexLocker ml(Heap_lock);
4063
4064 VMThread::wait_for_vm_thread_exit();
4065 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4066 VMThread::destroy();
4067 }
4068
4069 // clean up ideal graph printers
4070 #if defined(COMPILER2) && !defined(PRODUCT)
4071 IdealGraphPrinter::clean_up();
4072 #endif
4073
4074 // Now, all Java threads are gone except daemon threads. Daemon threads
4075 // running Java code or in VM are stopped by the Safepoint. However,
4076 // daemon threads executing native code are still running. But they
4077 // will be stopped at native=>Java/VM barriers. Note that we can't
4078 // simply kill or suspend them, as it is inherently deadlock-prone.
4079
4080 #ifndef PRODUCT
4081 // disable function tracing at JNI/JVM barriers
4082 TraceJNICalls = false;
4083 TraceJVMCalls = false;
4084 TraceRuntimeCalls = false;
4085 #endif
4086
4087 VM_Exit::set_vm_exited();
4088
4089 notify_vm_shutdown();
4090
4091 delete thread;
4092
4093 #if INCLUDE_JVMCI
4094 if (JVMCICounterSize > 0) {
4095 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
4096 }
4097 #endif
4098
4099 // exit_globals() will delete tty
4100 exit_globals();
4101
4102 LogConfiguration::finalize();
4103
4104 return true;
4105 }
4106
4107
4108 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4109 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4110 return is_supported_jni_version(version);
4111 }
4112
4113
4114 jboolean Threads::is_supported_jni_version(jint version) {
4115 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4116 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4117 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4118 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4119 return JNI_FALSE;
4120 }
4121
4122
4123 void Threads::add(JavaThread* p, bool force_daemon) {
4124 // The threads lock must be owned at this point
4125 assert_locked_or_safepoint(Threads_lock);
4126
4127 // See the comment for this method in thread.hpp for its purpose and
4128 // why it is called here.
4129 p->initialize_queues();
4130 p->set_next(_thread_list);
4131 _thread_list = p;
4132 _number_of_threads++;
4133 oop threadObj = p->threadObj();
4134 bool daemon = true;
4135 // Bootstrapping problem: threadObj can be null for initial
4136 // JavaThread (or for threads attached via JNI)
4137 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4138 _number_of_non_daemon_threads++;
4139 daemon = false;
4140 }
4141
4142 ThreadService::add_thread(p, daemon);
4143
4144 // Possible GC point.
4145 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
4146 }
4147
4148 void Threads::remove(JavaThread* p) {
4149 // Extra scope needed for Thread_lock, so we can check
4150 // that we do not remove thread without safepoint code notice
4151 { MutexLocker ml(Threads_lock);
4152
4153 assert(includes(p), "p must be present");
4154
4155 JavaThread* current = _thread_list;
4156 JavaThread* prev = NULL;
4157
4158 while (current != p) {
4159 prev = current;
4160 current = current->next();
4161 }
4162
4163 if (prev) {
4164 prev->set_next(current->next());
4165 } else {
4166 _thread_list = p->next();
4167 }
4168 _number_of_threads--;
4169 oop threadObj = p->threadObj();
4170 bool daemon = true;
4171 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4172 _number_of_non_daemon_threads--;
4173 daemon = false;
4174
4175 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4176 // on destroy_vm will wake up.
4177 if (number_of_non_daemon_threads() == 1) {
4178 Threads_lock->notify_all();
4179 }
4180 }
4181 ThreadService::remove_thread(p, daemon);
4182
4183 // Make sure that safepoint code disregard this thread. This is needed since
4184 // the thread might mess around with locks after this point. This can cause it
4185 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4186 // of this thread since it is removed from the queue.
4187 p->set_terminated_value();
4188 } // unlock Threads_lock
4189
4190 // Since Events::log uses a lock, we grab it outside the Threads_lock
4191 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
4192 }
4193
4194 // Threads_lock must be held when this is called (or must be called during a safepoint)
4195 bool Threads::includes(JavaThread* p) {
4196 assert(Threads_lock->is_locked(), "sanity check");
4197 ALL_JAVA_THREADS(q) {
4198 if (q == p) {
4199 return true;
4200 }
4201 }
4202 return false;
4203 }
4204
4205 // Operations on the Threads list for GC. These are not explicitly locked,
4206 // but the garbage collector must provide a safe context for them to run.
4207 // In particular, these things should never be called when the Threads_lock
4208 // is held by some other thread. (Note: the Safepoint abstraction also
4209 // uses the Threads_lock to guarantee this property. It also makes sure that
4210 // all threads gets blocked when exiting or starting).
4211
4212 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4213 ALL_JAVA_THREADS(p) {
4214 p->oops_do(f, cld_f, cf);
4215 }
4216 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4217 }
4218
4219 void Threads::change_thread_claim_parity() {
4220 // Set the new claim parity.
4221 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4222 "Not in range.");
4223 _thread_claim_parity++;
4224 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4225 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4226 "Not in range.");
4227 }
4228
4229 #ifdef ASSERT
4230 void Threads::assert_all_threads_claimed() {
4231 ALL_JAVA_THREADS(p) {
4232 const int thread_parity = p->oops_do_parity();
4233 assert((thread_parity == _thread_claim_parity),
4234 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
4235 }
4236 }
4237 #endif // ASSERT
4238
4239 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4240 int cp = Threads::thread_claim_parity();
4241 ALL_JAVA_THREADS(p) {
4242 if (p->claim_oops_do(is_par, cp)) {
4243 p->oops_do(f, cld_f, cf);
4244 }
4245 }
4246 VMThread* vmt = VMThread::vm_thread();
4247 if (vmt->claim_oops_do(is_par, cp)) {
4248 vmt->oops_do(f, cld_f, cf);
4249 }
4250 }
4251
4252 #if INCLUDE_ALL_GCS
4253 // Used by ParallelScavenge
4254 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4255 ALL_JAVA_THREADS(p) {
4256 q->enqueue(new ThreadRootsTask(p));
4257 }
4258 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4259 }
4260
4261 // Used by Parallel Old
4262 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4263 ALL_JAVA_THREADS(p) {
4264 q->enqueue(new ThreadRootsMarkingTask(p));
4265 }
4266 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4267 }
4268 #endif // INCLUDE_ALL_GCS
4269
4270 void Threads::nmethods_do(CodeBlobClosure* cf) {
4271 ALL_JAVA_THREADS(p) {
4272 p->nmethods_do(cf);
4273 }
4274 VMThread::vm_thread()->nmethods_do(cf);
4275 }
4276
4277 void Threads::metadata_do(void f(Metadata*)) {
4278 ALL_JAVA_THREADS(p) {
4279 p->metadata_do(f);
4280 }
4281 }
4282
4283 class ThreadHandlesClosure : public ThreadClosure {
4284 void (*_f)(Metadata*);
4285 public:
4286 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4287 virtual void do_thread(Thread* thread) {
4288 thread->metadata_handles_do(_f);
4289 }
4290 };
4291
4292 void Threads::metadata_handles_do(void f(Metadata*)) {
4293 // Only walk the Handles in Thread.
4294 ThreadHandlesClosure handles_closure(f);
4295 threads_do(&handles_closure);
4296 }
4297
4298 void Threads::deoptimized_wrt_marked_nmethods() {
4299 ALL_JAVA_THREADS(p) {
4300 p->deoptimized_wrt_marked_nmethods();
4301 }
4302 }
4303
4304
4305 // Get count Java threads that are waiting to enter the specified monitor.
4306 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4307 address monitor,
4308 bool doLock) {
4309 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4310 "must grab Threads_lock or be at safepoint");
4311 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4312
4313 int i = 0;
4314 {
4315 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4316 ALL_JAVA_THREADS(p) {
4317 if (!p->can_call_java()) continue;
4318
4319 address pending = (address)p->current_pending_monitor();
4320 if (pending == monitor) { // found a match
4321 if (i < count) result->append(p); // save the first count matches
4322 i++;
4323 }
4324 }
4325 }
4326 return result;
4327 }
4328
4329
4330 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4331 bool doLock) {
4332 assert(doLock ||
4333 Threads_lock->owned_by_self() ||
4334 SafepointSynchronize::is_at_safepoint(),
4335 "must grab Threads_lock or be at safepoint");
4336
4337 // NULL owner means not locked so we can skip the search
4338 if (owner == NULL) return NULL;
4339
4340 {
4341 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4342 ALL_JAVA_THREADS(p) {
4343 // first, see if owner is the address of a Java thread
4344 if (owner == (address)p) return p;
4345 }
4346 }
4347 // Cannot assert on lack of success here since this function may be
4348 // used by code that is trying to report useful problem information
4349 // like deadlock detection.
4350 if (UseHeavyMonitors) return NULL;
4351
4352 // If we didn't find a matching Java thread and we didn't force use of
4353 // heavyweight monitors, then the owner is the stack address of the
4354 // Lock Word in the owning Java thread's stack.
4355 //
4356 JavaThread* the_owner = NULL;
4357 {
4358 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4359 ALL_JAVA_THREADS(q) {
4360 if (q->is_lock_owned(owner)) {
4361 the_owner = q;
4362 break;
4363 }
4364 }
4365 }
4366 // cannot assert on lack of success here; see above comment
4367 return the_owner;
4368 }
4369
4370 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4371 void Threads::print_on(outputStream* st, bool print_stacks,
4372 bool internal_format, bool print_concurrent_locks) {
4373 char buf[32];
4374 st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
4375
4376 st->print_cr("Full thread dump %s (%s %s):",
4377 Abstract_VM_Version::vm_name(),
4378 Abstract_VM_Version::vm_release(),
4379 Abstract_VM_Version::vm_info_string());
4380 st->cr();
4381
4382 #if INCLUDE_SERVICES
4383 // Dump concurrent locks
4384 ConcurrentLocksDump concurrent_locks;
4385 if (print_concurrent_locks) {
4386 concurrent_locks.dump_at_safepoint();
4387 }
4388 #endif // INCLUDE_SERVICES
4389
4390 ALL_JAVA_THREADS(p) {
4391 ResourceMark rm;
4392 p->print_on(st);
4393 if (print_stacks) {
4394 if (internal_format) {
4395 p->trace_stack();
4396 } else {
4397 p->print_stack_on(st);
4398 }
4399 }
4400 st->cr();
4401 #if INCLUDE_SERVICES
4402 if (print_concurrent_locks) {
4403 concurrent_locks.print_locks_on(p, st);
4404 }
4405 #endif // INCLUDE_SERVICES
4406 }
4407
4408 VMThread::vm_thread()->print_on(st);
4409 st->cr();
4410 Universe::heap()->print_gc_threads_on(st);
4411 WatcherThread* wt = WatcherThread::watcher_thread();
4412 if (wt != NULL) {
4413 wt->print_on(st);
4414 st->cr();
4415 }
4416 CompileBroker::print_compiler_threads_on(st);
4417 st->flush();
4418 }
4419
4420 // Threads::print_on_error() is called by fatal error handler. It's possible
4421 // that VM is not at safepoint and/or current thread is inside signal handler.
4422 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4423 // memory (even in resource area), it might deadlock the error handler.
4424 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4425 int buflen) {
4426 bool found_current = false;
4427 st->print_cr("Java Threads: ( => current thread )");
4428 ALL_JAVA_THREADS(thread) {
4429 bool is_current = (current == thread);
4430 found_current = found_current || is_current;
4431
4432 st->print("%s", is_current ? "=>" : " ");
4433
4434 st->print(PTR_FORMAT, p2i(thread));
4435 st->print(" ");
4436 thread->print_on_error(st, buf, buflen);
4437 st->cr();
4438 }
4439 st->cr();
4440
4441 st->print_cr("Other Threads:");
4442 if (VMThread::vm_thread()) {
4443 bool is_current = (current == VMThread::vm_thread());
4444 found_current = found_current || is_current;
4445 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4446
4447 st->print(PTR_FORMAT, p2i(VMThread::vm_thread()));
4448 st->print(" ");
4449 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4450 st->cr();
4451 }
4452 WatcherThread* wt = WatcherThread::watcher_thread();
4453 if (wt != NULL) {
4454 bool is_current = (current == wt);
4455 found_current = found_current || is_current;
4456 st->print("%s", is_current ? "=>" : " ");
4457
4458 st->print(PTR_FORMAT, p2i(wt));
4459 st->print(" ");
4460 wt->print_on_error(st, buf, buflen);
4461 st->cr();
4462 }
4463 if (!found_current) {
4464 st->cr();
4465 st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
4466 current->print_on_error(st, buf, buflen);
4467 st->cr();
4468 }
4469 }
4470
4471 // Internal SpinLock and Mutex
4472 // Based on ParkEvent
4473
4474 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4475 //
4476 // We employ SpinLocks _only for low-contention, fixed-length
4477 // short-duration critical sections where we're concerned
4478 // about native mutex_t or HotSpot Mutex:: latency.
4479 // The mux construct provides a spin-then-block mutual exclusion
4480 // mechanism.
4481 //
4482 // Testing has shown that contention on the ListLock guarding gFreeList
4483 // is common. If we implement ListLock as a simple SpinLock it's common
4484 // for the JVM to devolve to yielding with little progress. This is true
4485 // despite the fact that the critical sections protected by ListLock are
4486 // extremely short.
4487 //
4488 // TODO-FIXME: ListLock should be of type SpinLock.
4489 // We should make this a 1st-class type, integrated into the lock
4490 // hierarchy as leaf-locks. Critically, the SpinLock structure
4491 // should have sufficient padding to avoid false-sharing and excessive
4492 // cache-coherency traffic.
4493
4494
4495 typedef volatile int SpinLockT;
4496
4497 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4498 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4499 return; // normal fast-path return
4500 }
4501
4502 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4503 TEVENT(SpinAcquire - ctx);
4504 int ctr = 0;
4505 int Yields = 0;
4506 for (;;) {
4507 while (*adr != 0) {
4508 ++ctr;
4509 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4510 if (Yields > 5) {
4511 os::naked_short_sleep(1);
4512 } else {
4513 os::naked_yield();
4514 ++Yields;
4515 }
4516 } else {
4517 SpinPause();
4518 }
4519 }
4520 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4521 }
4522 }
4523
4524 void Thread::SpinRelease(volatile int * adr) {
4525 assert(*adr != 0, "invariant");
4526 OrderAccess::fence(); // guarantee at least release consistency.
4527 // Roach-motel semantics.
4528 // It's safe if subsequent LDs and STs float "up" into the critical section,
4529 // but prior LDs and STs within the critical section can't be allowed
4530 // to reorder or float past the ST that releases the lock.
4531 // Loads and stores in the critical section - which appear in program
4532 // order before the store that releases the lock - must also appear
4533 // before the store that releases the lock in memory visibility order.
4534 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4535 // the ST of 0 into the lock-word which releases the lock, so fence
4536 // more than covers this on all platforms.
4537 *adr = 0;
4538 }
4539
4540 // muxAcquire and muxRelease:
4541 //
4542 // * muxAcquire and muxRelease support a single-word lock-word construct.
4543 // The LSB of the word is set IFF the lock is held.
4544 // The remainder of the word points to the head of a singly-linked list
4545 // of threads blocked on the lock.
4546 //
4547 // * The current implementation of muxAcquire-muxRelease uses its own
4548 // dedicated Thread._MuxEvent instance. If we're interested in
4549 // minimizing the peak number of extant ParkEvent instances then
4550 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4551 // as certain invariants were satisfied. Specifically, care would need
4552 // to be taken with regards to consuming unpark() "permits".
4553 // A safe rule of thumb is that a thread would never call muxAcquire()
4554 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4555 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4556 // consume an unpark() permit intended for monitorenter, for instance.
4557 // One way around this would be to widen the restricted-range semaphore
4558 // implemented in park(). Another alternative would be to provide
4559 // multiple instances of the PlatformEvent() for each thread. One
4560 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4561 //
4562 // * Usage:
4563 // -- Only as leaf locks
4564 // -- for short-term locking only as muxAcquire does not perform
4565 // thread state transitions.
4566 //
4567 // Alternatives:
4568 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4569 // but with parking or spin-then-park instead of pure spinning.
4570 // * Use Taura-Oyama-Yonenzawa locks.
4571 // * It's possible to construct a 1-0 lock if we encode the lockword as
4572 // (List,LockByte). Acquire will CAS the full lockword while Release
4573 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4574 // acquiring threads use timers (ParkTimed) to detect and recover from
4575 // the stranding window. Thread/Node structures must be aligned on 256-byte
4576 // boundaries by using placement-new.
4577 // * Augment MCS with advisory back-link fields maintained with CAS().
4578 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4579 // The validity of the backlinks must be ratified before we trust the value.
4580 // If the backlinks are invalid the exiting thread must back-track through the
4581 // the forward links, which are always trustworthy.
4582 // * Add a successor indication. The LockWord is currently encoded as
4583 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4584 // to provide the usual futile-wakeup optimization.
4585 // See RTStt for details.
4586 // * Consider schedctl.sc_nopreempt to cover the critical section.
4587 //
4588
4589
4590 typedef volatile intptr_t MutexT; // Mux Lock-word
4591 enum MuxBits { LOCKBIT = 1 };
4592
4593 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4594 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4595 if (w == 0) return;
4596 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4597 return;
4598 }
4599
4600 TEVENT(muxAcquire - Contention);
4601 ParkEvent * const Self = Thread::current()->_MuxEvent;
4602 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4603 for (;;) {
4604 int its = (os::is_MP() ? 100 : 0) + 1;
4605
4606 // Optional spin phase: spin-then-park strategy
4607 while (--its >= 0) {
4608 w = *Lock;
4609 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4610 return;
4611 }
4612 }
4613
4614 Self->reset();
4615 Self->OnList = intptr_t(Lock);
4616 // The following fence() isn't _strictly necessary as the subsequent
4617 // CAS() both serializes execution and ratifies the fetched *Lock value.
4618 OrderAccess::fence();
4619 for (;;) {
4620 w = *Lock;
4621 if ((w & LOCKBIT) == 0) {
4622 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4623 Self->OnList = 0; // hygiene - allows stronger asserts
4624 return;
4625 }
4626 continue; // Interference -- *Lock changed -- Just retry
4627 }
4628 assert(w & LOCKBIT, "invariant");
4629 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4630 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4631 }
4632
4633 while (Self->OnList != 0) {
4634 Self->park();
4635 }
4636 }
4637 }
4638
4639 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4640 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4641 if (w == 0) return;
4642 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4643 return;
4644 }
4645
4646 TEVENT(muxAcquire - Contention);
4647 ParkEvent * ReleaseAfter = NULL;
4648 if (ev == NULL) {
4649 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4650 }
4651 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4652 for (;;) {
4653 guarantee(ev->OnList == 0, "invariant");
4654 int its = (os::is_MP() ? 100 : 0) + 1;
4655
4656 // Optional spin phase: spin-then-park strategy
4657 while (--its >= 0) {
4658 w = *Lock;
4659 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4660 if (ReleaseAfter != NULL) {
4661 ParkEvent::Release(ReleaseAfter);
4662 }
4663 return;
4664 }
4665 }
4666
4667 ev->reset();
4668 ev->OnList = intptr_t(Lock);
4669 // The following fence() isn't _strictly necessary as the subsequent
4670 // CAS() both serializes execution and ratifies the fetched *Lock value.
4671 OrderAccess::fence();
4672 for (;;) {
4673 w = *Lock;
4674 if ((w & LOCKBIT) == 0) {
4675 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4676 ev->OnList = 0;
4677 // We call ::Release while holding the outer lock, thus
4678 // artificially lengthening the critical section.
4679 // Consider deferring the ::Release() until the subsequent unlock(),
4680 // after we've dropped the outer lock.
4681 if (ReleaseAfter != NULL) {
4682 ParkEvent::Release(ReleaseAfter);
4683 }
4684 return;
4685 }
4686 continue; // Interference -- *Lock changed -- Just retry
4687 }
4688 assert(w & LOCKBIT, "invariant");
4689 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4690 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4691 }
4692
4693 while (ev->OnList != 0) {
4694 ev->park();
4695 }
4696 }
4697 }
4698
4699 // Release() must extract a successor from the list and then wake that thread.
4700 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4701 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4702 // Release() would :
4703 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4704 // (B) Extract a successor from the private list "in-hand"
4705 // (C) attempt to CAS() the residual back into *Lock over null.
4706 // If there were any newly arrived threads and the CAS() would fail.
4707 // In that case Release() would detach the RATs, re-merge the list in-hand
4708 // with the RATs and repeat as needed. Alternately, Release() might
4709 // detach and extract a successor, but then pass the residual list to the wakee.
4710 // The wakee would be responsible for reattaching and remerging before it
4711 // competed for the lock.
4712 //
4713 // Both "pop" and DMR are immune from ABA corruption -- there can be
4714 // multiple concurrent pushers, but only one popper or detacher.
4715 // This implementation pops from the head of the list. This is unfair,
4716 // but tends to provide excellent throughput as hot threads remain hot.
4717 // (We wake recently run threads first).
4718 //
4719 // All paths through muxRelease() will execute a CAS.
4720 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4721 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4722 // executed within the critical section are complete and globally visible before the
4723 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4724 void Thread::muxRelease(volatile intptr_t * Lock) {
4725 for (;;) {
4726 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4727 assert(w & LOCKBIT, "invariant");
4728 if (w == LOCKBIT) return;
4729 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4730 assert(List != NULL, "invariant");
4731 assert(List->OnList == intptr_t(Lock), "invariant");
4732 ParkEvent * const nxt = List->ListNext;
4733 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4734
4735 // The following CAS() releases the lock and pops the head element.
4736 // The CAS() also ratifies the previously fetched lock-word value.
4737 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4738 continue;
4739 }
4740 List->OnList = 0;
4741 OrderAccess::fence();
4742 List->unpark();
4743 return;
4744 }
4745 }
4746
4747
4748 void Threads::verify() {
4749 ALL_JAVA_THREADS(p) {
4750 p->verify();
4751 }
4752 VMThread* thread = VMThread::vm_thread();
4753 if (thread != NULL) thread->verify();
4754 }