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