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