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