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 assert(SharedHeap::heap()->workers()->active_workers() > 0,
763 "Should only fail when parallel.");
764 return false;
765 }
766 }
767 assert(SharedHeap::heap()->workers()->active_workers() > 0,
768 "Should only fail when parallel.");
769 return false;
770 }
771
772 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
773 active_handles()->oops_do(f);
774 // Do oop for ThreadShadow
775 f->do_oop((oop*)&_pending_exception);
776 handle_area()->oops_do(f);
777 }
778
779 void Thread::nmethods_do(CodeBlobClosure* cf) {
780 // no nmethods in a generic thread...
781 }
782
783 void Thread::metadata_handles_do(void f(Metadata*)) {
784 // Only walk the Handles in Thread.
785 if (metadata_handles() != NULL) {
786 for (int i = 0; i< metadata_handles()->length(); i++) {
787 f(metadata_handles()->at(i));
788 }
789 }
790 }
791
792 void Thread::print_on(outputStream* st) const {
793 // get_priority assumes osthread initialized
794 if (osthread() != NULL) {
795 int os_prio;
796 if (os::get_native_priority(this, &os_prio) == OS_OK) {
797 st->print("os_prio=%d ", os_prio);
798 }
799 st->print("tid=" INTPTR_FORMAT " ", this);
800 ext().print_on(st);
801 osthread()->print_on(st);
802 }
803 debug_only(if (WizardMode) print_owned_locks_on(st);)
804 }
805
806 // Thread::print_on_error() is called by fatal error handler. Don't use
807 // any lock or allocate memory.
808 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
809 if (is_VM_thread()) st->print("VMThread");
810 else if (is_Compiler_thread()) st->print("CompilerThread");
811 else if (is_Java_thread()) st->print("JavaThread");
812 else if (is_GC_task_thread()) st->print("GCTaskThread");
813 else if (is_Watcher_thread()) st->print("WatcherThread");
814 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
815 else st->print("Thread");
816
817 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
818 _stack_base - _stack_size, _stack_base);
819
820 if (osthread()) {
821 st->print(" [id=%d]", osthread()->thread_id());
822 }
823 }
824
825 #ifdef ASSERT
826 void Thread::print_owned_locks_on(outputStream* st) const {
827 Monitor *cur = _owned_locks;
828 if (cur == NULL) {
829 st->print(" (no locks) ");
830 } else {
831 st->print_cr(" Locks owned:");
832 while (cur) {
833 cur->print_on(st);
834 cur = cur->next();
835 }
836 }
837 }
838
839 static int ref_use_count = 0;
840
841 bool Thread::owns_locks_but_compiled_lock() const {
842 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
843 if (cur != Compile_lock) return true;
844 }
845 return false;
846 }
847
848
849 #endif
850
851 #ifndef PRODUCT
852
853 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
854 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
855 // no threads which allow_vm_block's are held
856 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
857 // Check if current thread is allowed to block at a safepoint
858 if (!(_allow_safepoint_count == 0)) {
859 fatal("Possible safepoint reached by thread that does not allow it");
860 }
861 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
862 fatal("LEAF method calling lock?");
863 }
864
865 #ifdef ASSERT
866 if (potential_vm_operation && is_Java_thread()
867 && !Universe::is_bootstrapping()) {
868 // Make sure we do not hold any locks that the VM thread also uses.
869 // This could potentially lead to deadlocks
870 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
871 // Threads_lock is special, since the safepoint synchronization will not start before this is
872 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
873 // since it is used to transfer control between JavaThreads and the VMThread
874 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
875 if ((cur->allow_vm_block() &&
876 cur != Threads_lock &&
877 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
878 cur != VMOperationRequest_lock &&
879 cur != VMOperationQueue_lock) ||
880 cur->rank() == Mutex::special) {
881 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
882 }
883 }
884 }
885
886 if (GCALotAtAllSafepoints) {
887 // We could enter a safepoint here and thus have a gc
888 InterfaceSupport::check_gc_alot();
889 }
890 #endif
891 }
892 #endif
893
894 bool Thread::is_in_stack(address adr) const {
895 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
896 address end = os::current_stack_pointer();
897 // Allow non Java threads to call this without stack_base
898 if (_stack_base == NULL) return true;
899 if (stack_base() >= adr && adr >= end) return true;
900
901 return false;
902 }
903
904
905 bool Thread::is_in_usable_stack(address adr) const {
906 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
907 size_t usable_stack_size = _stack_size - stack_guard_size;
908
909 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
910 }
911
912
913 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
914 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
915 // used for compilation in the future. If that change is made, the need for these methods
916 // should be revisited, and they should be removed if possible.
917
918 bool Thread::is_lock_owned(address adr) const {
919 return on_local_stack(adr);
920 }
921
922 bool Thread::set_as_starting_thread() {
923 // NOTE: this must be called inside the main thread.
924 return os::create_main_thread((JavaThread*)this);
925 }
926
927 static void initialize_class(Symbol* class_name, TRAPS) {
928 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
929 InstanceKlass::cast(klass)->initialize(CHECK);
930 }
931
932
933 // Creates the initial ThreadGroup
934 static Handle create_initial_thread_group(TRAPS) {
935 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
936 instanceKlassHandle klass (THREAD, k);
937
938 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
939 {
940 JavaValue result(T_VOID);
941 JavaCalls::call_special(&result,
942 system_instance,
943 klass,
944 vmSymbols::object_initializer_name(),
945 vmSymbols::void_method_signature(),
946 CHECK_NH);
947 }
948 Universe::set_system_thread_group(system_instance());
949
950 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
951 {
952 JavaValue result(T_VOID);
953 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
954 JavaCalls::call_special(&result,
955 main_instance,
956 klass,
957 vmSymbols::object_initializer_name(),
958 vmSymbols::threadgroup_string_void_signature(),
959 system_instance,
960 string,
961 CHECK_NH);
962 }
963 return main_instance;
964 }
965
966 // Creates the initial Thread
967 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
968 TRAPS) {
969 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
970 instanceKlassHandle klass (THREAD, k);
971 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
972
973 java_lang_Thread::set_thread(thread_oop(), thread);
974 java_lang_Thread::set_priority(thread_oop(), NormPriority);
975 thread->set_threadObj(thread_oop());
976
977 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
978
979 JavaValue result(T_VOID);
980 JavaCalls::call_special(&result, thread_oop,
981 klass,
982 vmSymbols::object_initializer_name(),
983 vmSymbols::threadgroup_string_void_signature(),
984 thread_group,
985 string,
986 CHECK_NULL);
987 return thread_oop();
988 }
989
990 static void call_initializeSystemClass(TRAPS) {
991 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
992 instanceKlassHandle klass (THREAD, k);
993
994 JavaValue result(T_VOID);
995 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
996 vmSymbols::void_method_signature(), CHECK);
997 }
998
999 char java_runtime_name[128] = "";
1000 char java_runtime_version[128] = "";
1001
1002 // extract the JRE name from sun.misc.Version.java_runtime_name
1003 static const char* get_java_runtime_name(TRAPS) {
1004 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1005 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1006 fieldDescriptor fd;
1007 bool found = k != NULL &&
1008 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1009 vmSymbols::string_signature(), &fd);
1010 if (found) {
1011 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1012 if (name_oop == NULL) {
1013 return NULL;
1014 }
1015 const char* name = java_lang_String::as_utf8_string(name_oop,
1016 java_runtime_name,
1017 sizeof(java_runtime_name));
1018 return name;
1019 } else {
1020 return NULL;
1021 }
1022 }
1023
1024 // extract the JRE version from sun.misc.Version.java_runtime_version
1025 static const char* get_java_runtime_version(TRAPS) {
1026 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1027 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1028 fieldDescriptor fd;
1029 bool found = k != NULL &&
1030 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1031 vmSymbols::string_signature(), &fd);
1032 if (found) {
1033 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1034 if (name_oop == NULL) {
1035 return NULL;
1036 }
1037 const char* name = java_lang_String::as_utf8_string(name_oop,
1038 java_runtime_version,
1039 sizeof(java_runtime_version));
1040 return name;
1041 } else {
1042 return NULL;
1043 }
1044 }
1045
1046 // General purpose hook into Java code, run once when the VM is initialized.
1047 // The Java library method itself may be changed independently from the VM.
1048 static void call_postVMInitHook(TRAPS) {
1049 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1050 instanceKlassHandle klass (THREAD, k);
1051 if (klass.not_null()) {
1052 JavaValue result(T_VOID);
1053 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1054 vmSymbols::void_method_signature(),
1055 CHECK);
1056 }
1057 }
1058
1059 static void reset_vm_info_property(TRAPS) {
1060 // the vm info string
1061 ResourceMark rm(THREAD);
1062 const char *vm_info = VM_Version::vm_info_string();
1063
1064 // java.lang.System class
1065 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1066 instanceKlassHandle klass (THREAD, k);
1067
1068 // setProperty arguments
1069 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1070 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1071
1072 // return value
1073 JavaValue r(T_OBJECT);
1074
1075 // public static String setProperty(String key, String value);
1076 JavaCalls::call_static(&r,
1077 klass,
1078 vmSymbols::setProperty_name(),
1079 vmSymbols::string_string_string_signature(),
1080 key_str,
1081 value_str,
1082 CHECK);
1083 }
1084
1085
1086 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1087 bool daemon, TRAPS) {
1088 assert(thread_group.not_null(), "thread group should be specified");
1089 assert(threadObj() == NULL, "should only create Java thread object once");
1090
1091 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1092 instanceKlassHandle klass (THREAD, k);
1093 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1094
1095 java_lang_Thread::set_thread(thread_oop(), this);
1096 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1097 set_threadObj(thread_oop());
1098
1099 JavaValue result(T_VOID);
1100 if (thread_name != NULL) {
1101 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1102 // Thread gets assigned specified name and null target
1103 JavaCalls::call_special(&result,
1104 thread_oop,
1105 klass,
1106 vmSymbols::object_initializer_name(),
1107 vmSymbols::threadgroup_string_void_signature(),
1108 thread_group, // Argument 1
1109 name, // Argument 2
1110 THREAD);
1111 } else {
1112 // Thread gets assigned name "Thread-nnn" and null target
1113 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1114 JavaCalls::call_special(&result,
1115 thread_oop,
1116 klass,
1117 vmSymbols::object_initializer_name(),
1118 vmSymbols::threadgroup_runnable_void_signature(),
1119 thread_group, // Argument 1
1120 Handle(), // Argument 2
1121 THREAD);
1122 }
1123
1124
1125 if (daemon) {
1126 java_lang_Thread::set_daemon(thread_oop());
1127 }
1128
1129 if (HAS_PENDING_EXCEPTION) {
1130 return;
1131 }
1132
1133 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1134 Handle threadObj(THREAD, this->threadObj());
1135
1136 JavaCalls::call_special(&result,
1137 thread_group,
1138 group,
1139 vmSymbols::add_method_name(),
1140 vmSymbols::thread_void_signature(),
1141 threadObj, // Arg 1
1142 THREAD);
1143 }
1144
1145 // NamedThread -- non-JavaThread subclasses with multiple
1146 // uniquely named instances should derive from this.
1147 NamedThread::NamedThread() : Thread() {
1148 _name = NULL;
1149 _processed_thread = NULL;
1150 }
1151
1152 NamedThread::~NamedThread() {
1153 if (_name != NULL) {
1154 FREE_C_HEAP_ARRAY(char, _name);
1155 _name = NULL;
1156 }
1157 }
1158
1159 void NamedThread::set_name(const char* format, ...) {
1160 guarantee(_name == NULL, "Only get to set name once.");
1161 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1162 guarantee(_name != NULL, "alloc failure");
1163 va_list ap;
1164 va_start(ap, format);
1165 jio_vsnprintf(_name, max_name_len, format, ap);
1166 va_end(ap);
1167 }
1168
1169 void NamedThread::initialize_named_thread() {
1170 set_native_thread_name(name());
1171 }
1172
1173 void NamedThread::print_on(outputStream* st) const {
1174 st->print("\"%s\" ", name());
1175 Thread::print_on(st);
1176 st->cr();
1177 }
1178
1179
1180 // ======= WatcherThread ========
1181
1182 // The watcher thread exists to simulate timer interrupts. It should
1183 // be replaced by an abstraction over whatever native support for
1184 // timer interrupts exists on the platform.
1185
1186 WatcherThread* WatcherThread::_watcher_thread = NULL;
1187 bool WatcherThread::_startable = false;
1188 volatile bool WatcherThread::_should_terminate = false;
1189
1190 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1191 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1192 if (os::create_thread(this, os::watcher_thread)) {
1193 _watcher_thread = this;
1194
1195 // Set the watcher thread to the highest OS priority which should not be
1196 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1197 // is created. The only normal thread using this priority is the reference
1198 // handler thread, which runs for very short intervals only.
1199 // If the VMThread's priority is not lower than the WatcherThread profiling
1200 // will be inaccurate.
1201 os::set_priority(this, MaxPriority);
1202 if (!DisableStartThread) {
1203 os::start_thread(this);
1204 }
1205 }
1206 }
1207
1208 int WatcherThread::sleep() const {
1209 // The WatcherThread does not participate in the safepoint protocol
1210 // for the PeriodicTask_lock because it is not a JavaThread.
1211 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1212
1213 if (_should_terminate) {
1214 // check for termination before we do any housekeeping or wait
1215 return 0; // we did not sleep.
1216 }
1217
1218 // remaining will be zero if there are no tasks,
1219 // causing the WatcherThread to sleep until a task is
1220 // enrolled
1221 int remaining = PeriodicTask::time_to_wait();
1222 int time_slept = 0;
1223
1224 // we expect this to timeout - we only ever get unparked when
1225 // we should terminate or when a new task has been enrolled
1226 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1227
1228 jlong time_before_loop = os::javaTimeNanos();
1229
1230 while (true) {
1231 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1232 remaining);
1233 jlong now = os::javaTimeNanos();
1234
1235 if (remaining == 0) {
1236 // if we didn't have any tasks we could have waited for a long time
1237 // consider the time_slept zero and reset time_before_loop
1238 time_slept = 0;
1239 time_before_loop = now;
1240 } else {
1241 // need to recalculate since we might have new tasks in _tasks
1242 time_slept = (int) ((now - time_before_loop) / 1000000);
1243 }
1244
1245 // Change to task list or spurious wakeup of some kind
1246 if (timedout || _should_terminate) {
1247 break;
1248 }
1249
1250 remaining = PeriodicTask::time_to_wait();
1251 if (remaining == 0) {
1252 // Last task was just disenrolled so loop around and wait until
1253 // another task gets enrolled
1254 continue;
1255 }
1256
1257 remaining -= time_slept;
1258 if (remaining <= 0) {
1259 break;
1260 }
1261 }
1262
1263 return time_slept;
1264 }
1265
1266 void WatcherThread::run() {
1267 assert(this == watcher_thread(), "just checking");
1268
1269 this->record_stack_base_and_size();
1270 this->initialize_thread_local_storage();
1271 this->set_native_thread_name(this->name());
1272 this->set_active_handles(JNIHandleBlock::allocate_block());
1273 while (true) {
1274 assert(watcher_thread() == Thread::current(), "thread consistency check");
1275 assert(watcher_thread() == this, "thread consistency check");
1276
1277 // Calculate how long it'll be until the next PeriodicTask work
1278 // should be done, and sleep that amount of time.
1279 int time_waited = sleep();
1280
1281 if (is_error_reported()) {
1282 // A fatal error has happened, the error handler(VMError::report_and_die)
1283 // should abort JVM after creating an error log file. However in some
1284 // rare cases, the error handler itself might deadlock. Here we try to
1285 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1286 //
1287 // This code is in WatcherThread because WatcherThread wakes up
1288 // periodically so the fatal error handler doesn't need to do anything;
1289 // also because the WatcherThread is less likely to crash than other
1290 // threads.
1291
1292 for (;;) {
1293 if (!ShowMessageBoxOnError
1294 && (OnError == NULL || OnError[0] == '\0')
1295 && Arguments::abort_hook() == NULL) {
1296 os::sleep(this, 2 * 60 * 1000, false);
1297 fdStream err(defaultStream::output_fd());
1298 err.print_raw_cr("# [ timer expired, abort... ]");
1299 // skip atexit/vm_exit/vm_abort hooks
1300 os::die();
1301 }
1302
1303 // Wake up 5 seconds later, the fatal handler may reset OnError or
1304 // ShowMessageBoxOnError when it is ready to abort.
1305 os::sleep(this, 5 * 1000, false);
1306 }
1307 }
1308
1309 if (_should_terminate) {
1310 // check for termination before posting the next tick
1311 break;
1312 }
1313
1314 PeriodicTask::real_time_tick(time_waited);
1315 }
1316
1317 // Signal that it is terminated
1318 {
1319 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1320 _watcher_thread = NULL;
1321 Terminator_lock->notify();
1322 }
1323
1324 // Thread destructor usually does this..
1325 ThreadLocalStorage::set_thread(NULL);
1326 }
1327
1328 void WatcherThread::start() {
1329 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1330
1331 if (watcher_thread() == NULL && _startable) {
1332 _should_terminate = false;
1333 // Create the single instance of WatcherThread
1334 new WatcherThread();
1335 }
1336 }
1337
1338 void WatcherThread::make_startable() {
1339 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1340 _startable = true;
1341 }
1342
1343 void WatcherThread::stop() {
1344 {
1345 // Follow normal safepoint aware lock enter protocol since the
1346 // WatcherThread is stopped by another JavaThread.
1347 MutexLocker ml(PeriodicTask_lock);
1348 _should_terminate = true;
1349
1350 WatcherThread* watcher = watcher_thread();
1351 if (watcher != NULL) {
1352 // unpark the WatcherThread so it can see that it should terminate
1353 watcher->unpark();
1354 }
1355 }
1356
1357 MutexLocker mu(Terminator_lock);
1358
1359 while (watcher_thread() != NULL) {
1360 // This wait should make safepoint checks, wait without a timeout,
1361 // and wait as a suspend-equivalent condition.
1362 //
1363 // Note: If the FlatProfiler is running, then this thread is waiting
1364 // for the WatcherThread to terminate and the WatcherThread, via the
1365 // FlatProfiler task, is waiting for the external suspend request on
1366 // this thread to complete. wait_for_ext_suspend_completion() will
1367 // eventually timeout, but that takes time. Making this wait a
1368 // suspend-equivalent condition solves that timeout problem.
1369 //
1370 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1371 Mutex::_as_suspend_equivalent_flag);
1372 }
1373 }
1374
1375 void WatcherThread::unpark() {
1376 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1377 PeriodicTask_lock->notify();
1378 }
1379
1380 void WatcherThread::print_on(outputStream* st) const {
1381 st->print("\"%s\" ", name());
1382 Thread::print_on(st);
1383 st->cr();
1384 }
1385
1386 // ======= JavaThread ========
1387
1388 // A JavaThread is a normal Java thread
1389
1390 void JavaThread::initialize() {
1391 // Initialize fields
1392
1393 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1394 set_claimed_par_id(UINT_MAX);
1395
1396 set_saved_exception_pc(NULL);
1397 set_threadObj(NULL);
1398 _anchor.clear();
1399 set_entry_point(NULL);
1400 set_jni_functions(jni_functions());
1401 set_callee_target(NULL);
1402 set_vm_result(NULL);
1403 set_vm_result_2(NULL);
1404 set_vframe_array_head(NULL);
1405 set_vframe_array_last(NULL);
1406 set_deferred_locals(NULL);
1407 set_deopt_mark(NULL);
1408 set_deopt_nmethod(NULL);
1409 clear_must_deopt_id();
1410 set_monitor_chunks(NULL);
1411 set_next(NULL);
1412 set_thread_state(_thread_new);
1413 _terminated = _not_terminated;
1414 _privileged_stack_top = NULL;
1415 _array_for_gc = NULL;
1416 _suspend_equivalent = false;
1417 _in_deopt_handler = 0;
1418 _doing_unsafe_access = false;
1419 _stack_guard_state = stack_guard_unused;
1420 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1421 _exception_pc = 0;
1422 _exception_handler_pc = 0;
1423 _is_method_handle_return = 0;
1424 _jvmti_thread_state= NULL;
1425 _should_post_on_exceptions_flag = JNI_FALSE;
1426 _jvmti_get_loaded_classes_closure = NULL;
1427 _interp_only_mode = 0;
1428 _special_runtime_exit_condition = _no_async_condition;
1429 _pending_async_exception = NULL;
1430 _thread_stat = NULL;
1431 _thread_stat = new ThreadStatistics();
1432 _blocked_on_compilation = false;
1433 _jni_active_critical = 0;
1434 _pending_jni_exception_check_fn = NULL;
1435 _do_not_unlock_if_synchronized = false;
1436 _cached_monitor_info = NULL;
1437 _parker = Parker::Allocate(this);
1438
1439 #ifndef PRODUCT
1440 _jmp_ring_index = 0;
1441 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1442 record_jump(NULL, NULL, NULL, 0);
1443 }
1444 #endif // PRODUCT
1445
1446 set_thread_profiler(NULL);
1447 if (FlatProfiler::is_active()) {
1448 // This is where we would decide to either give each thread it's own profiler
1449 // or use one global one from FlatProfiler,
1450 // or up to some count of the number of profiled threads, etc.
1451 ThreadProfiler* pp = new ThreadProfiler();
1452 pp->engage();
1453 set_thread_profiler(pp);
1454 }
1455
1456 // Setup safepoint state info for this thread
1457 ThreadSafepointState::create(this);
1458
1459 debug_only(_java_call_counter = 0);
1460
1461 // JVMTI PopFrame support
1462 _popframe_condition = popframe_inactive;
1463 _popframe_preserved_args = NULL;
1464 _popframe_preserved_args_size = 0;
1465 _frames_to_pop_failed_realloc = 0;
1466
1467 pd_initialize();
1468 }
1469
1470 #if INCLUDE_ALL_GCS
1471 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1472 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1473 #endif // INCLUDE_ALL_GCS
1474
1475 JavaThread::JavaThread(bool is_attaching_via_jni) :
1476 Thread()
1477 #if INCLUDE_ALL_GCS
1478 , _satb_mark_queue(&_satb_mark_queue_set),
1479 _dirty_card_queue(&_dirty_card_queue_set)
1480 #endif // INCLUDE_ALL_GCS
1481 {
1482 initialize();
1483 if (is_attaching_via_jni) {
1484 _jni_attach_state = _attaching_via_jni;
1485 } else {
1486 _jni_attach_state = _not_attaching_via_jni;
1487 }
1488 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1489 }
1490
1491 bool JavaThread::reguard_stack(address cur_sp) {
1492 if (_stack_guard_state != stack_guard_yellow_disabled) {
1493 return true; // Stack already guarded or guard pages not needed.
1494 }
1495
1496 if (register_stack_overflow()) {
1497 // For those architectures which have separate register and
1498 // memory stacks, we must check the register stack to see if
1499 // it has overflowed.
1500 return false;
1501 }
1502
1503 // Java code never executes within the yellow zone: the latter is only
1504 // there to provoke an exception during stack banging. If java code
1505 // is executing there, either StackShadowPages should be larger, or
1506 // some exception code in c1, c2 or the interpreter isn't unwinding
1507 // when it should.
1508 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1509
1510 enable_stack_yellow_zone();
1511 return true;
1512 }
1513
1514 bool JavaThread::reguard_stack(void) {
1515 return reguard_stack(os::current_stack_pointer());
1516 }
1517
1518
1519 void JavaThread::block_if_vm_exited() {
1520 if (_terminated == _vm_exited) {
1521 // _vm_exited is set at safepoint, and Threads_lock is never released
1522 // we will block here forever
1523 Threads_lock->lock_without_safepoint_check();
1524 ShouldNotReachHere();
1525 }
1526 }
1527
1528
1529 // Remove this ifdef when C1 is ported to the compiler interface.
1530 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1531 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1532
1533 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1534 Thread()
1535 #if INCLUDE_ALL_GCS
1536 , _satb_mark_queue(&_satb_mark_queue_set),
1537 _dirty_card_queue(&_dirty_card_queue_set)
1538 #endif // INCLUDE_ALL_GCS
1539 {
1540 initialize();
1541 _jni_attach_state = _not_attaching_via_jni;
1542 set_entry_point(entry_point);
1543 // Create the native thread itself.
1544 // %note runtime_23
1545 os::ThreadType thr_type = os::java_thread;
1546 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1547 os::java_thread;
1548 os::create_thread(this, thr_type, stack_sz);
1549 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1550 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1551 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1552 // the exception consists of creating the exception object & initializing it, initialization
1553 // will leave the VM via a JavaCall and then all locks must be unlocked).
1554 //
1555 // The thread is still suspended when we reach here. Thread must be explicit started
1556 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1557 // by calling Threads:add. The reason why this is not done here, is because the thread
1558 // object must be fully initialized (take a look at JVM_Start)
1559 }
1560
1561 JavaThread::~JavaThread() {
1562
1563 // JSR166 -- return the parker to the free list
1564 Parker::Release(_parker);
1565 _parker = NULL;
1566
1567 // Free any remaining previous UnrollBlock
1568 vframeArray* old_array = vframe_array_last();
1569
1570 if (old_array != NULL) {
1571 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1572 old_array->set_unroll_block(NULL);
1573 delete old_info;
1574 delete old_array;
1575 }
1576
1577 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1578 if (deferred != NULL) {
1579 // This can only happen if thread is destroyed before deoptimization occurs.
1580 assert(deferred->length() != 0, "empty array!");
1581 do {
1582 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1583 deferred->remove_at(0);
1584 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1585 delete dlv;
1586 } while (deferred->length() != 0);
1587 delete deferred;
1588 }
1589
1590 // All Java related clean up happens in exit
1591 ThreadSafepointState::destroy(this);
1592 if (_thread_profiler != NULL) delete _thread_profiler;
1593 if (_thread_stat != NULL) delete _thread_stat;
1594 }
1595
1596
1597 // The first routine called by a new Java thread
1598 void JavaThread::run() {
1599 // initialize thread-local alloc buffer related fields
1600 this->initialize_tlab();
1601
1602 // used to test validity of stack trace backs
1603 this->record_base_of_stack_pointer();
1604
1605 // Record real stack base and size.
1606 this->record_stack_base_and_size();
1607
1608 // Initialize thread local storage; set before calling MutexLocker
1609 this->initialize_thread_local_storage();
1610
1611 this->create_stack_guard_pages();
1612
1613 this->cache_global_variables();
1614
1615 // Thread is now sufficient initialized to be handled by the safepoint code as being
1616 // in the VM. Change thread state from _thread_new to _thread_in_vm
1617 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1618
1619 assert(JavaThread::current() == this, "sanity check");
1620 assert(!Thread::current()->owns_locks(), "sanity check");
1621
1622 DTRACE_THREAD_PROBE(start, this);
1623
1624 // This operation might block. We call that after all safepoint checks for a new thread has
1625 // been completed.
1626 this->set_active_handles(JNIHandleBlock::allocate_block());
1627
1628 if (JvmtiExport::should_post_thread_life()) {
1629 JvmtiExport::post_thread_start(this);
1630 }
1631
1632 EventThreadStart event;
1633 if (event.should_commit()) {
1634 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1635 event.commit();
1636 }
1637
1638 // We call another function to do the rest so we are sure that the stack addresses used
1639 // from there will be lower than the stack base just computed
1640 thread_main_inner();
1641
1642 // Note, thread is no longer valid at this point!
1643 }
1644
1645
1646 void JavaThread::thread_main_inner() {
1647 assert(JavaThread::current() == this, "sanity check");
1648 assert(this->threadObj() != NULL, "just checking");
1649
1650 // Execute thread entry point unless this thread has a pending exception
1651 // or has been stopped before starting.
1652 // Note: Due to JVM_StopThread we can have pending exceptions already!
1653 if (!this->has_pending_exception() &&
1654 !java_lang_Thread::is_stillborn(this->threadObj())) {
1655 {
1656 ResourceMark rm(this);
1657 this->set_native_thread_name(this->get_thread_name());
1658 }
1659 HandleMark hm(this);
1660 this->entry_point()(this, this);
1661 }
1662
1663 DTRACE_THREAD_PROBE(stop, this);
1664
1665 this->exit(false);
1666 delete this;
1667 }
1668
1669
1670 static void ensure_join(JavaThread* thread) {
1671 // We do not need to grap the Threads_lock, since we are operating on ourself.
1672 Handle threadObj(thread, thread->threadObj());
1673 assert(threadObj.not_null(), "java thread object must exist");
1674 ObjectLocker lock(threadObj, thread);
1675 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1676 thread->clear_pending_exception();
1677 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1678 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1679 // Clear the native thread instance - this makes isAlive return false and allows the join()
1680 // to complete once we've done the notify_all below
1681 java_lang_Thread::set_thread(threadObj(), NULL);
1682 lock.notify_all(thread);
1683 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1684 thread->clear_pending_exception();
1685 }
1686
1687
1688 // For any new cleanup additions, please check to see if they need to be applied to
1689 // cleanup_failed_attach_current_thread as well.
1690 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1691 assert(this == JavaThread::current(), "thread consistency check");
1692
1693 HandleMark hm(this);
1694 Handle uncaught_exception(this, this->pending_exception());
1695 this->clear_pending_exception();
1696 Handle threadObj(this, this->threadObj());
1697 assert(threadObj.not_null(), "Java thread object should be created");
1698
1699 if (get_thread_profiler() != NULL) {
1700 get_thread_profiler()->disengage();
1701 ResourceMark rm;
1702 get_thread_profiler()->print(get_thread_name());
1703 }
1704
1705
1706 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1707 {
1708 EXCEPTION_MARK;
1709
1710 CLEAR_PENDING_EXCEPTION;
1711 }
1712 if (!destroy_vm) {
1713 if (uncaught_exception.not_null()) {
1714 EXCEPTION_MARK;
1715 // Call method Thread.dispatchUncaughtException().
1716 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1717 JavaValue result(T_VOID);
1718 JavaCalls::call_virtual(&result,
1719 threadObj, thread_klass,
1720 vmSymbols::dispatchUncaughtException_name(),
1721 vmSymbols::throwable_void_signature(),
1722 uncaught_exception,
1723 THREAD);
1724 if (HAS_PENDING_EXCEPTION) {
1725 ResourceMark rm(this);
1726 jio_fprintf(defaultStream::error_stream(),
1727 "\nException: %s thrown from the UncaughtExceptionHandler"
1728 " in thread \"%s\"\n",
1729 pending_exception()->klass()->external_name(),
1730 get_thread_name());
1731 CLEAR_PENDING_EXCEPTION;
1732 }
1733 }
1734
1735 // Called before the java thread exit since we want to read info
1736 // from java_lang_Thread object
1737 EventThreadEnd event;
1738 if (event.should_commit()) {
1739 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1740 event.commit();
1741 }
1742
1743 // Call after last event on thread
1744 EVENT_THREAD_EXIT(this);
1745
1746 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1747 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1748 // is deprecated anyhow.
1749 if (!is_Compiler_thread()) {
1750 int count = 3;
1751 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1752 EXCEPTION_MARK;
1753 JavaValue result(T_VOID);
1754 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1755 JavaCalls::call_virtual(&result,
1756 threadObj, thread_klass,
1757 vmSymbols::exit_method_name(),
1758 vmSymbols::void_method_signature(),
1759 THREAD);
1760 CLEAR_PENDING_EXCEPTION;
1761 }
1762 }
1763 // notify JVMTI
1764 if (JvmtiExport::should_post_thread_life()) {
1765 JvmtiExport::post_thread_end(this);
1766 }
1767
1768 // We have notified the agents that we are exiting, before we go on,
1769 // we must check for a pending external suspend request and honor it
1770 // in order to not surprise the thread that made the suspend request.
1771 while (true) {
1772 {
1773 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1774 if (!is_external_suspend()) {
1775 set_terminated(_thread_exiting);
1776 ThreadService::current_thread_exiting(this);
1777 break;
1778 }
1779 // Implied else:
1780 // Things get a little tricky here. We have a pending external
1781 // suspend request, but we are holding the SR_lock so we
1782 // can't just self-suspend. So we temporarily drop the lock
1783 // and then self-suspend.
1784 }
1785
1786 ThreadBlockInVM tbivm(this);
1787 java_suspend_self();
1788
1789 // We're done with this suspend request, but we have to loop around
1790 // and check again. Eventually we will get SR_lock without a pending
1791 // external suspend request and will be able to mark ourselves as
1792 // exiting.
1793 }
1794 // no more external suspends are allowed at this point
1795 } else {
1796 // before_exit() has already posted JVMTI THREAD_END events
1797 }
1798
1799 // Notify waiters on thread object. This has to be done after exit() is called
1800 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1801 // group should have the destroyed bit set before waiters are notified).
1802 ensure_join(this);
1803 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1804
1805 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1806 // held by this thread must be released. A detach operation must only
1807 // get here if there are no Java frames on the stack. Therefore, any
1808 // owned monitors at this point MUST be JNI-acquired monitors which are
1809 // pre-inflated and in the monitor cache.
1810 //
1811 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1812 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1813 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1814 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1815 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1816 }
1817
1818 // These things needs to be done while we are still a Java Thread. Make sure that thread
1819 // is in a consistent state, in case GC happens
1820 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1821
1822 if (active_handles() != NULL) {
1823 JNIHandleBlock* block = active_handles();
1824 set_active_handles(NULL);
1825 JNIHandleBlock::release_block(block);
1826 }
1827
1828 if (free_handle_block() != NULL) {
1829 JNIHandleBlock* block = free_handle_block();
1830 set_free_handle_block(NULL);
1831 JNIHandleBlock::release_block(block);
1832 }
1833
1834 // These have to be removed while this is still a valid thread.
1835 remove_stack_guard_pages();
1836
1837 if (UseTLAB) {
1838 tlab().make_parsable(true); // retire TLAB
1839 }
1840
1841 if (JvmtiEnv::environments_might_exist()) {
1842 JvmtiExport::cleanup_thread(this);
1843 }
1844
1845 // We must flush any deferred card marks before removing a thread from
1846 // the list of active threads.
1847 Universe::heap()->flush_deferred_store_barrier(this);
1848 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1849
1850 #if INCLUDE_ALL_GCS
1851 // We must flush the G1-related buffers before removing a thread
1852 // from the list of active threads. We must do this after any deferred
1853 // card marks have been flushed (above) so that any entries that are
1854 // added to the thread's dirty card queue as a result are not lost.
1855 if (UseG1GC) {
1856 flush_barrier_queues();
1857 }
1858 #endif // INCLUDE_ALL_GCS
1859
1860 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1861 Threads::remove(this);
1862 }
1863
1864 #if INCLUDE_ALL_GCS
1865 // Flush G1-related queues.
1866 void JavaThread::flush_barrier_queues() {
1867 satb_mark_queue().flush();
1868 dirty_card_queue().flush();
1869 }
1870
1871 void JavaThread::initialize_queues() {
1872 assert(!SafepointSynchronize::is_at_safepoint(),
1873 "we should not be at a safepoint");
1874
1875 ObjPtrQueue& satb_queue = satb_mark_queue();
1876 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1877 // The SATB queue should have been constructed with its active
1878 // field set to false.
1879 assert(!satb_queue.is_active(), "SATB queue should not be active");
1880 assert(satb_queue.is_empty(), "SATB queue should be empty");
1881 // If we are creating the thread during a marking cycle, we should
1882 // set the active field of the SATB queue to true.
1883 if (satb_queue_set.is_active()) {
1884 satb_queue.set_active(true);
1885 }
1886
1887 DirtyCardQueue& dirty_queue = dirty_card_queue();
1888 // The dirty card queue should have been constructed with its
1889 // active field set to true.
1890 assert(dirty_queue.is_active(), "dirty card queue should be active");
1891 }
1892 #endif // INCLUDE_ALL_GCS
1893
1894 void JavaThread::cleanup_failed_attach_current_thread() {
1895 if (get_thread_profiler() != NULL) {
1896 get_thread_profiler()->disengage();
1897 ResourceMark rm;
1898 get_thread_profiler()->print(get_thread_name());
1899 }
1900
1901 if (active_handles() != NULL) {
1902 JNIHandleBlock* block = active_handles();
1903 set_active_handles(NULL);
1904 JNIHandleBlock::release_block(block);
1905 }
1906
1907 if (free_handle_block() != NULL) {
1908 JNIHandleBlock* block = free_handle_block();
1909 set_free_handle_block(NULL);
1910 JNIHandleBlock::release_block(block);
1911 }
1912
1913 // These have to be removed while this is still a valid thread.
1914 remove_stack_guard_pages();
1915
1916 if (UseTLAB) {
1917 tlab().make_parsable(true); // retire TLAB, if any
1918 }
1919
1920 #if INCLUDE_ALL_GCS
1921 if (UseG1GC) {
1922 flush_barrier_queues();
1923 }
1924 #endif // INCLUDE_ALL_GCS
1925
1926 Threads::remove(this);
1927 delete this;
1928 }
1929
1930
1931
1932
1933 JavaThread* JavaThread::active() {
1934 Thread* thread = ThreadLocalStorage::thread();
1935 assert(thread != NULL, "just checking");
1936 if (thread->is_Java_thread()) {
1937 return (JavaThread*) thread;
1938 } else {
1939 assert(thread->is_VM_thread(), "this must be a vm thread");
1940 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1941 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1942 assert(ret->is_Java_thread(), "must be a Java thread");
1943 return ret;
1944 }
1945 }
1946
1947 bool JavaThread::is_lock_owned(address adr) const {
1948 if (Thread::is_lock_owned(adr)) return true;
1949
1950 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1951 if (chunk->contains(adr)) return true;
1952 }
1953
1954 return false;
1955 }
1956
1957
1958 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1959 chunk->set_next(monitor_chunks());
1960 set_monitor_chunks(chunk);
1961 }
1962
1963 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1964 guarantee(monitor_chunks() != NULL, "must be non empty");
1965 if (monitor_chunks() == chunk) {
1966 set_monitor_chunks(chunk->next());
1967 } else {
1968 MonitorChunk* prev = monitor_chunks();
1969 while (prev->next() != chunk) prev = prev->next();
1970 prev->set_next(chunk->next());
1971 }
1972 }
1973
1974 // JVM support.
1975
1976 // Note: this function shouldn't block if it's called in
1977 // _thread_in_native_trans state (such as from
1978 // check_special_condition_for_native_trans()).
1979 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1980
1981 if (has_last_Java_frame() && has_async_condition()) {
1982 // If we are at a polling page safepoint (not a poll return)
1983 // then we must defer async exception because live registers
1984 // will be clobbered by the exception path. Poll return is
1985 // ok because the call we a returning from already collides
1986 // with exception handling registers and so there is no issue.
1987 // (The exception handling path kills call result registers but
1988 // this is ok since the exception kills the result anyway).
1989
1990 if (is_at_poll_safepoint()) {
1991 // if the code we are returning to has deoptimized we must defer
1992 // the exception otherwise live registers get clobbered on the
1993 // exception path before deoptimization is able to retrieve them.
1994 //
1995 RegisterMap map(this, false);
1996 frame caller_fr = last_frame().sender(&map);
1997 assert(caller_fr.is_compiled_frame(), "what?");
1998 if (caller_fr.is_deoptimized_frame()) {
1999 if (TraceExceptions) {
2000 ResourceMark rm;
2001 tty->print_cr("deferred async exception at compiled safepoint");
2002 }
2003 return;
2004 }
2005 }
2006 }
2007
2008 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2009 if (condition == _no_async_condition) {
2010 // Conditions have changed since has_special_runtime_exit_condition()
2011 // was called:
2012 // - if we were here only because of an external suspend request,
2013 // then that was taken care of above (or cancelled) so we are done
2014 // - if we were here because of another async request, then it has
2015 // been cleared between the has_special_runtime_exit_condition()
2016 // and now so again we are done
2017 return;
2018 }
2019
2020 // Check for pending async. exception
2021 if (_pending_async_exception != NULL) {
2022 // Only overwrite an already pending exception, if it is not a threadDeath.
2023 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2024
2025 // We cannot call Exceptions::_throw(...) here because we cannot block
2026 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2027
2028 if (TraceExceptions) {
2029 ResourceMark rm;
2030 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2031 if (has_last_Java_frame()) {
2032 frame f = last_frame();
2033 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2034 }
2035 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2036 }
2037 _pending_async_exception = NULL;
2038 clear_has_async_exception();
2039 }
2040 }
2041
2042 if (check_unsafe_error &&
2043 condition == _async_unsafe_access_error && !has_pending_exception()) {
2044 condition = _no_async_condition; // done
2045 switch (thread_state()) {
2046 case _thread_in_vm: {
2047 JavaThread* THREAD = this;
2048 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2049 }
2050 case _thread_in_native: {
2051 ThreadInVMfromNative tiv(this);
2052 JavaThread* THREAD = this;
2053 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2054 }
2055 case _thread_in_Java: {
2056 ThreadInVMfromJava tiv(this);
2057 JavaThread* THREAD = this;
2058 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2059 }
2060 default:
2061 ShouldNotReachHere();
2062 }
2063 }
2064
2065 assert(condition == _no_async_condition || has_pending_exception() ||
2066 (!check_unsafe_error && condition == _async_unsafe_access_error),
2067 "must have handled the async condition, if no exception");
2068 }
2069
2070 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2071 //
2072 // Check for pending external suspend. Internal suspend requests do
2073 // not use handle_special_runtime_exit_condition().
2074 // If JNIEnv proxies are allowed, don't self-suspend if the target
2075 // thread is not the current thread. In older versions of jdbx, jdbx
2076 // threads could call into the VM with another thread's JNIEnv so we
2077 // can be here operating on behalf of a suspended thread (4432884).
2078 bool do_self_suspend = is_external_suspend_with_lock();
2079 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2080 //
2081 // Because thread is external suspended the safepoint code will count
2082 // thread as at a safepoint. This can be odd because we can be here
2083 // as _thread_in_Java which would normally transition to _thread_blocked
2084 // at a safepoint. We would like to mark the thread as _thread_blocked
2085 // before calling java_suspend_self like all other callers of it but
2086 // we must then observe proper safepoint protocol. (We can't leave
2087 // _thread_blocked with a safepoint in progress). However we can be
2088 // here as _thread_in_native_trans so we can't use a normal transition
2089 // constructor/destructor pair because they assert on that type of
2090 // transition. We could do something like:
2091 //
2092 // JavaThreadState state = thread_state();
2093 // set_thread_state(_thread_in_vm);
2094 // {
2095 // ThreadBlockInVM tbivm(this);
2096 // java_suspend_self()
2097 // }
2098 // set_thread_state(_thread_in_vm_trans);
2099 // if (safepoint) block;
2100 // set_thread_state(state);
2101 //
2102 // but that is pretty messy. Instead we just go with the way the
2103 // code has worked before and note that this is the only path to
2104 // java_suspend_self that doesn't put the thread in _thread_blocked
2105 // mode.
2106
2107 frame_anchor()->make_walkable(this);
2108 java_suspend_self();
2109
2110 // We might be here for reasons in addition to the self-suspend request
2111 // so check for other async requests.
2112 }
2113
2114 if (check_asyncs) {
2115 check_and_handle_async_exceptions();
2116 }
2117 }
2118
2119 void JavaThread::send_thread_stop(oop java_throwable) {
2120 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2121 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2122 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2123
2124 // Do not throw asynchronous exceptions against the compiler thread
2125 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2126 if (is_Compiler_thread()) return;
2127
2128 {
2129 // Actually throw the Throwable against the target Thread - however
2130 // only if there is no thread death exception installed already.
2131 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2132 // If the topmost frame is a runtime stub, then we are calling into
2133 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2134 // must deoptimize the caller before continuing, as the compiled exception handler table
2135 // may not be valid
2136 if (has_last_Java_frame()) {
2137 frame f = last_frame();
2138 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2139 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2140 RegisterMap reg_map(this, UseBiasedLocking);
2141 frame compiled_frame = f.sender(®_map);
2142 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2143 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2144 }
2145 }
2146 }
2147
2148 // Set async. pending exception in thread.
2149 set_pending_async_exception(java_throwable);
2150
2151 if (TraceExceptions) {
2152 ResourceMark rm;
2153 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2154 }
2155 // for AbortVMOnException flag
2156 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2157 }
2158 }
2159
2160
2161 // Interrupt thread so it will wake up from a potential wait()
2162 Thread::interrupt(this);
2163 }
2164
2165 // External suspension mechanism.
2166 //
2167 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2168 // to any VM_locks and it is at a transition
2169 // Self-suspension will happen on the transition out of the vm.
2170 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2171 //
2172 // Guarantees on return:
2173 // + Target thread will not execute any new bytecode (that's why we need to
2174 // force a safepoint)
2175 // + Target thread will not enter any new monitors
2176 //
2177 void JavaThread::java_suspend() {
2178 { MutexLocker mu(Threads_lock);
2179 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2180 return;
2181 }
2182 }
2183
2184 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2185 if (!is_external_suspend()) {
2186 // a racing resume has cancelled us; bail out now
2187 return;
2188 }
2189
2190 // suspend is done
2191 uint32_t debug_bits = 0;
2192 // Warning: is_ext_suspend_completed() may temporarily drop the
2193 // SR_lock to allow the thread to reach a stable thread state if
2194 // it is currently in a transient thread state.
2195 if (is_ext_suspend_completed(false /* !called_by_wait */,
2196 SuspendRetryDelay, &debug_bits)) {
2197 return;
2198 }
2199 }
2200
2201 VM_ForceSafepoint vm_suspend;
2202 VMThread::execute(&vm_suspend);
2203 }
2204
2205 // Part II of external suspension.
2206 // A JavaThread self suspends when it detects a pending external suspend
2207 // request. This is usually on transitions. It is also done in places
2208 // where continuing to the next transition would surprise the caller,
2209 // e.g., monitor entry.
2210 //
2211 // Returns the number of times that the thread self-suspended.
2212 //
2213 // Note: DO NOT call java_suspend_self() when you just want to block current
2214 // thread. java_suspend_self() is the second stage of cooperative
2215 // suspension for external suspend requests and should only be used
2216 // to complete an external suspend request.
2217 //
2218 int JavaThread::java_suspend_self() {
2219 int ret = 0;
2220
2221 // we are in the process of exiting so don't suspend
2222 if (is_exiting()) {
2223 clear_external_suspend();
2224 return ret;
2225 }
2226
2227 assert(_anchor.walkable() ||
2228 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2229 "must have walkable stack");
2230
2231 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2232
2233 assert(!this->is_ext_suspended(),
2234 "a thread trying to self-suspend should not already be suspended");
2235
2236 if (this->is_suspend_equivalent()) {
2237 // If we are self-suspending as a result of the lifting of a
2238 // suspend equivalent condition, then the suspend_equivalent
2239 // flag is not cleared until we set the ext_suspended flag so
2240 // that wait_for_ext_suspend_completion() returns consistent
2241 // results.
2242 this->clear_suspend_equivalent();
2243 }
2244
2245 // A racing resume may have cancelled us before we grabbed SR_lock
2246 // above. Or another external suspend request could be waiting for us
2247 // by the time we return from SR_lock()->wait(). The thread
2248 // that requested the suspension may already be trying to walk our
2249 // stack and if we return now, we can change the stack out from under
2250 // it. This would be a "bad thing (TM)" and cause the stack walker
2251 // to crash. We stay self-suspended until there are no more pending
2252 // external suspend requests.
2253 while (is_external_suspend()) {
2254 ret++;
2255 this->set_ext_suspended();
2256
2257 // _ext_suspended flag is cleared by java_resume()
2258 while (is_ext_suspended()) {
2259 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2260 }
2261 }
2262
2263 return ret;
2264 }
2265
2266 #ifdef ASSERT
2267 // verify the JavaThread has not yet been published in the Threads::list, and
2268 // hence doesn't need protection from concurrent access at this stage
2269 void JavaThread::verify_not_published() {
2270 if (!Threads_lock->owned_by_self()) {
2271 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2272 assert(!Threads::includes(this),
2273 "java thread shouldn't have been published yet!");
2274 } else {
2275 assert(!Threads::includes(this),
2276 "java thread shouldn't have been published yet!");
2277 }
2278 }
2279 #endif
2280
2281 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2282 // progress or when _suspend_flags is non-zero.
2283 // Current thread needs to self-suspend if there is a suspend request and/or
2284 // block if a safepoint is in progress.
2285 // Async exception ISN'T checked.
2286 // Note only the ThreadInVMfromNative transition can call this function
2287 // directly and when thread state is _thread_in_native_trans
2288 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2289 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2290
2291 JavaThread *curJT = JavaThread::current();
2292 bool do_self_suspend = thread->is_external_suspend();
2293
2294 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2295
2296 // If JNIEnv proxies are allowed, don't self-suspend if the target
2297 // thread is not the current thread. In older versions of jdbx, jdbx
2298 // threads could call into the VM with another thread's JNIEnv so we
2299 // can be here operating on behalf of a suspended thread (4432884).
2300 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2301 JavaThreadState state = thread->thread_state();
2302
2303 // We mark this thread_blocked state as a suspend-equivalent so
2304 // that a caller to is_ext_suspend_completed() won't be confused.
2305 // The suspend-equivalent state is cleared by java_suspend_self().
2306 thread->set_suspend_equivalent();
2307
2308 // If the safepoint code sees the _thread_in_native_trans state, it will
2309 // wait until the thread changes to other thread state. There is no
2310 // guarantee on how soon we can obtain the SR_lock and complete the
2311 // self-suspend request. It would be a bad idea to let safepoint wait for
2312 // too long. Temporarily change the state to _thread_blocked to
2313 // let the VM thread know that this thread is ready for GC. The problem
2314 // of changing thread state is that safepoint could happen just after
2315 // java_suspend_self() returns after being resumed, and VM thread will
2316 // see the _thread_blocked state. We must check for safepoint
2317 // after restoring the state and make sure we won't leave while a safepoint
2318 // is in progress.
2319 thread->set_thread_state(_thread_blocked);
2320 thread->java_suspend_self();
2321 thread->set_thread_state(state);
2322 // Make sure new state is seen by VM thread
2323 if (os::is_MP()) {
2324 if (UseMembar) {
2325 // Force a fence between the write above and read below
2326 OrderAccess::fence();
2327 } else {
2328 // Must use this rather than serialization page in particular on Windows
2329 InterfaceSupport::serialize_memory(thread);
2330 }
2331 }
2332 }
2333
2334 if (SafepointSynchronize::do_call_back()) {
2335 // If we are safepointing, then block the caller which may not be
2336 // the same as the target thread (see above).
2337 SafepointSynchronize::block(curJT);
2338 }
2339
2340 if (thread->is_deopt_suspend()) {
2341 thread->clear_deopt_suspend();
2342 RegisterMap map(thread, false);
2343 frame f = thread->last_frame();
2344 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2345 f = f.sender(&map);
2346 }
2347 if (f.id() == thread->must_deopt_id()) {
2348 thread->clear_must_deopt_id();
2349 f.deoptimize(thread);
2350 } else {
2351 fatal("missed deoptimization!");
2352 }
2353 }
2354 }
2355
2356 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2357 // progress or when _suspend_flags is non-zero.
2358 // Current thread needs to self-suspend if there is a suspend request and/or
2359 // block if a safepoint is in progress.
2360 // Also check for pending async exception (not including unsafe access error).
2361 // Note only the native==>VM/Java barriers can call this function and when
2362 // thread state is _thread_in_native_trans.
2363 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2364 check_safepoint_and_suspend_for_native_trans(thread);
2365
2366 if (thread->has_async_exception()) {
2367 // We are in _thread_in_native_trans state, don't handle unsafe
2368 // access error since that may block.
2369 thread->check_and_handle_async_exceptions(false);
2370 }
2371 }
2372
2373 // This is a variant of the normal
2374 // check_special_condition_for_native_trans with slightly different
2375 // semantics for use by critical native wrappers. It does all the
2376 // normal checks but also performs the transition back into
2377 // thread_in_Java state. This is required so that critical natives
2378 // can potentially block and perform a GC if they are the last thread
2379 // exiting the GC_locker.
2380 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2381 check_special_condition_for_native_trans(thread);
2382
2383 // Finish the transition
2384 thread->set_thread_state(_thread_in_Java);
2385
2386 if (thread->do_critical_native_unlock()) {
2387 ThreadInVMfromJavaNoAsyncException tiv(thread);
2388 GC_locker::unlock_critical(thread);
2389 thread->clear_critical_native_unlock();
2390 }
2391 }
2392
2393 // We need to guarantee the Threads_lock here, since resumes are not
2394 // allowed during safepoint synchronization
2395 // Can only resume from an external suspension
2396 void JavaThread::java_resume() {
2397 assert_locked_or_safepoint(Threads_lock);
2398
2399 // Sanity check: thread is gone, has started exiting or the thread
2400 // was not externally suspended.
2401 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2402 return;
2403 }
2404
2405 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2406
2407 clear_external_suspend();
2408
2409 if (is_ext_suspended()) {
2410 clear_ext_suspended();
2411 SR_lock()->notify_all();
2412 }
2413 }
2414
2415 void JavaThread::create_stack_guard_pages() {
2416 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2417 address low_addr = stack_base() - stack_size();
2418 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2419
2420 int allocate = os::allocate_stack_guard_pages();
2421 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2422
2423 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2424 warning("Attempt to allocate stack guard pages failed.");
2425 return;
2426 }
2427
2428 if (os::guard_memory((char *) low_addr, len)) {
2429 _stack_guard_state = stack_guard_enabled;
2430 } else {
2431 warning("Attempt to protect stack guard pages failed.");
2432 if (os::uncommit_memory((char *) low_addr, len)) {
2433 warning("Attempt to deallocate stack guard pages failed.");
2434 }
2435 }
2436 }
2437
2438 void JavaThread::remove_stack_guard_pages() {
2439 assert(Thread::current() == this, "from different thread");
2440 if (_stack_guard_state == stack_guard_unused) return;
2441 address low_addr = stack_base() - stack_size();
2442 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2443
2444 if (os::allocate_stack_guard_pages()) {
2445 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2446 _stack_guard_state = stack_guard_unused;
2447 } else {
2448 warning("Attempt to deallocate stack guard pages failed.");
2449 }
2450 } else {
2451 if (_stack_guard_state == stack_guard_unused) return;
2452 if (os::unguard_memory((char *) low_addr, len)) {
2453 _stack_guard_state = stack_guard_unused;
2454 } else {
2455 warning("Attempt to unprotect stack guard pages failed.");
2456 }
2457 }
2458 }
2459
2460 void JavaThread::enable_stack_yellow_zone() {
2461 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2462 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2463
2464 // The base notation is from the stacks point of view, growing downward.
2465 // We need to adjust it to work correctly with guard_memory()
2466 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2467
2468 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2469 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2470
2471 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2472 _stack_guard_state = stack_guard_enabled;
2473 } else {
2474 warning("Attempt to guard stack yellow zone failed.");
2475 }
2476 enable_register_stack_guard();
2477 }
2478
2479 void JavaThread::disable_stack_yellow_zone() {
2480 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2481 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2482
2483 // Simply return if called for a thread that does not use guard pages.
2484 if (_stack_guard_state == stack_guard_unused) return;
2485
2486 // The base notation is from the stacks point of view, growing downward.
2487 // We need to adjust it to work correctly with guard_memory()
2488 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2489
2490 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2491 _stack_guard_state = stack_guard_yellow_disabled;
2492 } else {
2493 warning("Attempt to unguard stack yellow zone failed.");
2494 }
2495 disable_register_stack_guard();
2496 }
2497
2498 void JavaThread::enable_stack_red_zone() {
2499 // The base notation is from the stacks point of view, growing downward.
2500 // We need to adjust it to work correctly with guard_memory()
2501 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2502 address base = stack_red_zone_base() - stack_red_zone_size();
2503
2504 guarantee(base < stack_base(), "Error calculating stack red zone");
2505 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2506
2507 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2508 warning("Attempt to guard stack red zone failed.");
2509 }
2510 }
2511
2512 void JavaThread::disable_stack_red_zone() {
2513 // The base notation is from the stacks point of view, growing downward.
2514 // We need to adjust it to work correctly with guard_memory()
2515 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2516 address base = stack_red_zone_base() - stack_red_zone_size();
2517 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2518 warning("Attempt to unguard stack red zone failed.");
2519 }
2520 }
2521
2522 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2523 // ignore is there is no stack
2524 if (!has_last_Java_frame()) return;
2525 // traverse the stack frames. Starts from top frame.
2526 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2527 frame* fr = fst.current();
2528 f(fr, fst.register_map());
2529 }
2530 }
2531
2532
2533 #ifndef PRODUCT
2534 // Deoptimization
2535 // Function for testing deoptimization
2536 void JavaThread::deoptimize() {
2537 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2538 StackFrameStream fst(this, UseBiasedLocking);
2539 bool deopt = false; // Dump stack only if a deopt actually happens.
2540 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2541 // Iterate over all frames in the thread and deoptimize
2542 for (; !fst.is_done(); fst.next()) {
2543 if (fst.current()->can_be_deoptimized()) {
2544
2545 if (only_at) {
2546 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2547 // consists of comma or carriage return separated numbers so
2548 // search for the current bci in that string.
2549 address pc = fst.current()->pc();
2550 nmethod* nm = (nmethod*) fst.current()->cb();
2551 ScopeDesc* sd = nm->scope_desc_at(pc);
2552 char buffer[8];
2553 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2554 size_t len = strlen(buffer);
2555 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2556 while (found != NULL) {
2557 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2558 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2559 // Check that the bci found is bracketed by terminators.
2560 break;
2561 }
2562 found = strstr(found + 1, buffer);
2563 }
2564 if (!found) {
2565 continue;
2566 }
2567 }
2568
2569 if (DebugDeoptimization && !deopt) {
2570 deopt = true; // One-time only print before deopt
2571 tty->print_cr("[BEFORE Deoptimization]");
2572 trace_frames();
2573 trace_stack();
2574 }
2575 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2576 }
2577 }
2578
2579 if (DebugDeoptimization && deopt) {
2580 tty->print_cr("[AFTER Deoptimization]");
2581 trace_frames();
2582 }
2583 }
2584
2585
2586 // Make zombies
2587 void JavaThread::make_zombies() {
2588 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2589 if (fst.current()->can_be_deoptimized()) {
2590 // it is a Java nmethod
2591 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2592 nm->make_not_entrant();
2593 }
2594 }
2595 }
2596 #endif // PRODUCT
2597
2598
2599 void JavaThread::deoptimized_wrt_marked_nmethods() {
2600 if (!has_last_Java_frame()) return;
2601 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2602 StackFrameStream fst(this, UseBiasedLocking);
2603 for (; !fst.is_done(); fst.next()) {
2604 if (fst.current()->should_be_deoptimized()) {
2605 if (LogCompilation && xtty != NULL) {
2606 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2607 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2608 this->name(), nm != NULL ? nm->compile_id() : -1);
2609 }
2610
2611 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2612 }
2613 }
2614 }
2615
2616
2617 // If the caller is a NamedThread, then remember, in the current scope,
2618 // the given JavaThread in its _processed_thread field.
2619 class RememberProcessedThread: public StackObj {
2620 NamedThread* _cur_thr;
2621 public:
2622 RememberProcessedThread(JavaThread* jthr) {
2623 Thread* thread = Thread::current();
2624 if (thread->is_Named_thread()) {
2625 _cur_thr = (NamedThread *)thread;
2626 _cur_thr->set_processed_thread(jthr);
2627 } else {
2628 _cur_thr = NULL;
2629 }
2630 }
2631
2632 ~RememberProcessedThread() {
2633 if (_cur_thr) {
2634 _cur_thr->set_processed_thread(NULL);
2635 }
2636 }
2637 };
2638
2639 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2640 // Verify that the deferred card marks have been flushed.
2641 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2642
2643 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2644 // since there may be more than one thread using each ThreadProfiler.
2645
2646 // Traverse the GCHandles
2647 Thread::oops_do(f, cld_f, cf);
2648
2649 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2650 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2651
2652 if (has_last_Java_frame()) {
2653 // Record JavaThread to GC thread
2654 RememberProcessedThread rpt(this);
2655
2656 // Traverse the privileged stack
2657 if (_privileged_stack_top != NULL) {
2658 _privileged_stack_top->oops_do(f);
2659 }
2660
2661 // traverse the registered growable array
2662 if (_array_for_gc != NULL) {
2663 for (int index = 0; index < _array_for_gc->length(); index++) {
2664 f->do_oop(_array_for_gc->adr_at(index));
2665 }
2666 }
2667
2668 // Traverse the monitor chunks
2669 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2670 chunk->oops_do(f);
2671 }
2672
2673 // Traverse the execution stack
2674 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2675 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2676 }
2677 }
2678
2679 // callee_target is never live across a gc point so NULL it here should
2680 // it still contain a methdOop.
2681
2682 set_callee_target(NULL);
2683
2684 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2685 // If we have deferred set_locals there might be oops waiting to be
2686 // written
2687 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2688 if (list != NULL) {
2689 for (int i = 0; i < list->length(); i++) {
2690 list->at(i)->oops_do(f);
2691 }
2692 }
2693
2694 // Traverse instance variables at the end since the GC may be moving things
2695 // around using this function
2696 f->do_oop((oop*) &_threadObj);
2697 f->do_oop((oop*) &_vm_result);
2698 f->do_oop((oop*) &_exception_oop);
2699 f->do_oop((oop*) &_pending_async_exception);
2700
2701 if (jvmti_thread_state() != NULL) {
2702 jvmti_thread_state()->oops_do(f);
2703 }
2704 }
2705
2706 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2707 Thread::nmethods_do(cf); // (super method is a no-op)
2708
2709 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2710 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2711
2712 if (has_last_Java_frame()) {
2713 // Traverse the execution stack
2714 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2715 fst.current()->nmethods_do(cf);
2716 }
2717 }
2718 }
2719
2720 void JavaThread::metadata_do(void f(Metadata*)) {
2721 if (has_last_Java_frame()) {
2722 // Traverse the execution stack to call f() on the methods in the stack
2723 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2724 fst.current()->metadata_do(f);
2725 }
2726 } else if (is_Compiler_thread()) {
2727 // need to walk ciMetadata in current compile tasks to keep alive.
2728 CompilerThread* ct = (CompilerThread*)this;
2729 if (ct->env() != NULL) {
2730 ct->env()->metadata_do(f);
2731 }
2732 }
2733 }
2734
2735 // Printing
2736 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2737 switch (_thread_state) {
2738 case _thread_uninitialized: return "_thread_uninitialized";
2739 case _thread_new: return "_thread_new";
2740 case _thread_new_trans: return "_thread_new_trans";
2741 case _thread_in_native: return "_thread_in_native";
2742 case _thread_in_native_trans: return "_thread_in_native_trans";
2743 case _thread_in_vm: return "_thread_in_vm";
2744 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2745 case _thread_in_Java: return "_thread_in_Java";
2746 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2747 case _thread_blocked: return "_thread_blocked";
2748 case _thread_blocked_trans: return "_thread_blocked_trans";
2749 default: return "unknown thread state";
2750 }
2751 }
2752
2753 #ifndef PRODUCT
2754 void JavaThread::print_thread_state_on(outputStream *st) const {
2755 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2756 };
2757 void JavaThread::print_thread_state() const {
2758 print_thread_state_on(tty);
2759 }
2760 #endif // PRODUCT
2761
2762 // Called by Threads::print() for VM_PrintThreads operation
2763 void JavaThread::print_on(outputStream *st) const {
2764 st->print("\"%s\" ", get_thread_name());
2765 oop thread_oop = threadObj();
2766 if (thread_oop != NULL) {
2767 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2768 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2769 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2770 }
2771 Thread::print_on(st);
2772 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2773 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2774 if (thread_oop != NULL) {
2775 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2776 }
2777 #ifndef PRODUCT
2778 print_thread_state_on(st);
2779 _safepoint_state->print_on(st);
2780 #endif // PRODUCT
2781 }
2782
2783 // Called by fatal error handler. The difference between this and
2784 // JavaThread::print() is that we can't grab lock or allocate memory.
2785 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2786 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2787 oop thread_obj = threadObj();
2788 if (thread_obj != NULL) {
2789 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2790 }
2791 st->print(" [");
2792 st->print("%s", _get_thread_state_name(_thread_state));
2793 if (osthread()) {
2794 st->print(", id=%d", osthread()->thread_id());
2795 }
2796 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2797 _stack_base - _stack_size, _stack_base);
2798 st->print("]");
2799 return;
2800 }
2801
2802 // Verification
2803
2804 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2805
2806 void JavaThread::verify() {
2807 // Verify oops in the thread.
2808 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2809
2810 // Verify the stack frames.
2811 frames_do(frame_verify);
2812 }
2813
2814 // CR 6300358 (sub-CR 2137150)
2815 // Most callers of this method assume that it can't return NULL but a
2816 // thread may not have a name whilst it is in the process of attaching to
2817 // the VM - see CR 6412693, and there are places where a JavaThread can be
2818 // seen prior to having it's threadObj set (eg JNI attaching threads and
2819 // if vm exit occurs during initialization). These cases can all be accounted
2820 // for such that this method never returns NULL.
2821 const char* JavaThread::get_thread_name() const {
2822 #ifdef ASSERT
2823 // early safepoints can hit while current thread does not yet have TLS
2824 if (!SafepointSynchronize::is_at_safepoint()) {
2825 Thread *cur = Thread::current();
2826 if (!(cur->is_Java_thread() && cur == this)) {
2827 // Current JavaThreads are allowed to get their own name without
2828 // the Threads_lock.
2829 assert_locked_or_safepoint(Threads_lock);
2830 }
2831 }
2832 #endif // ASSERT
2833 return get_thread_name_string();
2834 }
2835
2836 // Returns a non-NULL representation of this thread's name, or a suitable
2837 // descriptive string if there is no set name
2838 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2839 const char* name_str;
2840 oop thread_obj = threadObj();
2841 if (thread_obj != NULL) {
2842 oop name = java_lang_Thread::name(thread_obj);
2843 if (name != NULL) {
2844 if (buf == NULL) {
2845 name_str = java_lang_String::as_utf8_string(name);
2846 } else {
2847 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2848 }
2849 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2850 name_str = "<no-name - thread is attaching>";
2851 } else {
2852 name_str = Thread::name();
2853 }
2854 } else {
2855 name_str = Thread::name();
2856 }
2857 assert(name_str != NULL, "unexpected NULL thread name");
2858 return name_str;
2859 }
2860
2861
2862 const char* JavaThread::get_threadgroup_name() const {
2863 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2864 oop thread_obj = threadObj();
2865 if (thread_obj != NULL) {
2866 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2867 if (thread_group != NULL) {
2868 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2869 // ThreadGroup.name can be null
2870 if (name != NULL) {
2871 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2872 return str;
2873 }
2874 }
2875 }
2876 return NULL;
2877 }
2878
2879 const char* JavaThread::get_parent_name() const {
2880 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2881 oop thread_obj = threadObj();
2882 if (thread_obj != NULL) {
2883 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2884 if (thread_group != NULL) {
2885 oop parent = java_lang_ThreadGroup::parent(thread_group);
2886 if (parent != NULL) {
2887 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2888 // ThreadGroup.name can be null
2889 if (name != NULL) {
2890 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2891 return str;
2892 }
2893 }
2894 }
2895 }
2896 return NULL;
2897 }
2898
2899 ThreadPriority JavaThread::java_priority() const {
2900 oop thr_oop = threadObj();
2901 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2902 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2903 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2904 return priority;
2905 }
2906
2907 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2908
2909 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2910 // Link Java Thread object <-> C++ Thread
2911
2912 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2913 // and put it into a new Handle. The Handle "thread_oop" can then
2914 // be used to pass the C++ thread object to other methods.
2915
2916 // Set the Java level thread object (jthread) field of the
2917 // new thread (a JavaThread *) to C++ thread object using the
2918 // "thread_oop" handle.
2919
2920 // Set the thread field (a JavaThread *) of the
2921 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2922
2923 Handle thread_oop(Thread::current(),
2924 JNIHandles::resolve_non_null(jni_thread));
2925 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2926 "must be initialized");
2927 set_threadObj(thread_oop());
2928 java_lang_Thread::set_thread(thread_oop(), this);
2929
2930 if (prio == NoPriority) {
2931 prio = java_lang_Thread::priority(thread_oop());
2932 assert(prio != NoPriority, "A valid priority should be present");
2933 }
2934
2935 // Push the Java priority down to the native thread; needs Threads_lock
2936 Thread::set_priority(this, prio);
2937
2938 prepare_ext();
2939
2940 // Add the new thread to the Threads list and set it in motion.
2941 // We must have threads lock in order to call Threads::add.
2942 // It is crucial that we do not block before the thread is
2943 // added to the Threads list for if a GC happens, then the java_thread oop
2944 // will not be visited by GC.
2945 Threads::add(this);
2946 }
2947
2948 oop JavaThread::current_park_blocker() {
2949 // Support for JSR-166 locks
2950 oop thread_oop = threadObj();
2951 if (thread_oop != NULL &&
2952 JDK_Version::current().supports_thread_park_blocker()) {
2953 return java_lang_Thread::park_blocker(thread_oop);
2954 }
2955 return NULL;
2956 }
2957
2958
2959 void JavaThread::print_stack_on(outputStream* st) {
2960 if (!has_last_Java_frame()) return;
2961 ResourceMark rm;
2962 HandleMark hm;
2963
2964 RegisterMap reg_map(this);
2965 vframe* start_vf = last_java_vframe(®_map);
2966 int count = 0;
2967 for (vframe* f = start_vf; f; f = f->sender()) {
2968 if (f->is_java_frame()) {
2969 javaVFrame* jvf = javaVFrame::cast(f);
2970 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2971
2972 // Print out lock information
2973 if (JavaMonitorsInStackTrace) {
2974 jvf->print_lock_info_on(st, count);
2975 }
2976 } else {
2977 // Ignore non-Java frames
2978 }
2979
2980 // Bail-out case for too deep stacks
2981 count++;
2982 if (MaxJavaStackTraceDepth == count) return;
2983 }
2984 }
2985
2986
2987 // JVMTI PopFrame support
2988 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2989 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2990 if (in_bytes(size_in_bytes) != 0) {
2991 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
2992 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2993 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2994 }
2995 }
2996
2997 void* JavaThread::popframe_preserved_args() {
2998 return _popframe_preserved_args;
2999 }
3000
3001 ByteSize JavaThread::popframe_preserved_args_size() {
3002 return in_ByteSize(_popframe_preserved_args_size);
3003 }
3004
3005 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3006 int sz = in_bytes(popframe_preserved_args_size());
3007 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3008 return in_WordSize(sz / wordSize);
3009 }
3010
3011 void JavaThread::popframe_free_preserved_args() {
3012 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3013 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3014 _popframe_preserved_args = NULL;
3015 _popframe_preserved_args_size = 0;
3016 }
3017
3018 #ifndef PRODUCT
3019
3020 void JavaThread::trace_frames() {
3021 tty->print_cr("[Describe stack]");
3022 int frame_no = 1;
3023 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3024 tty->print(" %d. ", frame_no++);
3025 fst.current()->print_value_on(tty, this);
3026 tty->cr();
3027 }
3028 }
3029
3030 class PrintAndVerifyOopClosure: public OopClosure {
3031 protected:
3032 template <class T> inline void do_oop_work(T* p) {
3033 oop obj = oopDesc::load_decode_heap_oop(p);
3034 if (obj == NULL) return;
3035 tty->print(INTPTR_FORMAT ": ", p);
3036 if (obj->is_oop_or_null()) {
3037 if (obj->is_objArray()) {
3038 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3039 } else {
3040 obj->print();
3041 }
3042 } else {
3043 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3044 }
3045 tty->cr();
3046 }
3047 public:
3048 virtual void do_oop(oop* p) { do_oop_work(p); }
3049 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3050 };
3051
3052
3053 static void oops_print(frame* f, const RegisterMap *map) {
3054 PrintAndVerifyOopClosure print;
3055 f->print_value();
3056 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3057 }
3058
3059 // Print our all the locations that contain oops and whether they are
3060 // valid or not. This useful when trying to find the oldest frame
3061 // where an oop has gone bad since the frame walk is from youngest to
3062 // oldest.
3063 void JavaThread::trace_oops() {
3064 tty->print_cr("[Trace oops]");
3065 frames_do(oops_print);
3066 }
3067
3068
3069 #ifdef ASSERT
3070 // Print or validate the layout of stack frames
3071 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3072 ResourceMark rm;
3073 PRESERVE_EXCEPTION_MARK;
3074 FrameValues values;
3075 int frame_no = 0;
3076 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3077 fst.current()->describe(values, ++frame_no);
3078 if (depth == frame_no) break;
3079 }
3080 if (validate_only) {
3081 values.validate();
3082 } else {
3083 tty->print_cr("[Describe stack layout]");
3084 values.print(this);
3085 }
3086 }
3087 #endif
3088
3089 void JavaThread::trace_stack_from(vframe* start_vf) {
3090 ResourceMark rm;
3091 int vframe_no = 1;
3092 for (vframe* f = start_vf; f; f = f->sender()) {
3093 if (f->is_java_frame()) {
3094 javaVFrame::cast(f)->print_activation(vframe_no++);
3095 } else {
3096 f->print();
3097 }
3098 if (vframe_no > StackPrintLimit) {
3099 tty->print_cr("...<more frames>...");
3100 return;
3101 }
3102 }
3103 }
3104
3105
3106 void JavaThread::trace_stack() {
3107 if (!has_last_Java_frame()) return;
3108 ResourceMark rm;
3109 HandleMark hm;
3110 RegisterMap reg_map(this);
3111 trace_stack_from(last_java_vframe(®_map));
3112 }
3113
3114
3115 #endif // PRODUCT
3116
3117
3118 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3119 assert(reg_map != NULL, "a map must be given");
3120 frame f = last_frame();
3121 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3122 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3123 }
3124 return NULL;
3125 }
3126
3127
3128 Klass* JavaThread::security_get_caller_class(int depth) {
3129 vframeStream vfst(this);
3130 vfst.security_get_caller_frame(depth);
3131 if (!vfst.at_end()) {
3132 return vfst.method()->method_holder();
3133 }
3134 return NULL;
3135 }
3136
3137 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3138 assert(thread->is_Compiler_thread(), "must be compiler thread");
3139 CompileBroker::compiler_thread_loop();
3140 }
3141
3142 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3143 NMethodSweeper::sweeper_loop();
3144 }
3145
3146 // Create a CompilerThread
3147 CompilerThread::CompilerThread(CompileQueue* queue,
3148 CompilerCounters* counters)
3149 : JavaThread(&compiler_thread_entry) {
3150 _env = NULL;
3151 _log = NULL;
3152 _task = NULL;
3153 _queue = queue;
3154 _counters = counters;
3155 _buffer_blob = NULL;
3156 _compiler = NULL;
3157
3158 #ifndef PRODUCT
3159 _ideal_graph_printer = NULL;
3160 #endif
3161 }
3162
3163 // Create sweeper thread
3164 CodeCacheSweeperThread::CodeCacheSweeperThread()
3165 : JavaThread(&sweeper_thread_entry) {
3166 _scanned_nmethod = NULL;
3167 }
3168 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3169 JavaThread::oops_do(f, cld_f, cf);
3170 if (_scanned_nmethod != NULL && cf != NULL) {
3171 // Safepoints can occur when the sweeper is scanning an nmethod so
3172 // process it here to make sure it isn't unloaded in the middle of
3173 // a scan.
3174 cf->do_code_blob(_scanned_nmethod);
3175 }
3176 }
3177
3178
3179 // ======= Threads ========
3180
3181 // The Threads class links together all active threads, and provides
3182 // operations over all threads. It is protected by its own Mutex
3183 // lock, which is also used in other contexts to protect thread
3184 // operations from having the thread being operated on from exiting
3185 // and going away unexpectedly (e.g., safepoint synchronization)
3186
3187 JavaThread* Threads::_thread_list = NULL;
3188 int Threads::_number_of_threads = 0;
3189 int Threads::_number_of_non_daemon_threads = 0;
3190 int Threads::_return_code = 0;
3191 size_t JavaThread::_stack_size_at_create = 0;
3192 #ifdef ASSERT
3193 bool Threads::_vm_complete = false;
3194 #endif
3195
3196 // All JavaThreads
3197 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3198
3199 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3200 void Threads::threads_do(ThreadClosure* tc) {
3201 assert_locked_or_safepoint(Threads_lock);
3202 // ALL_JAVA_THREADS iterates through all JavaThreads
3203 ALL_JAVA_THREADS(p) {
3204 tc->do_thread(p);
3205 }
3206 // Someday we could have a table or list of all non-JavaThreads.
3207 // For now, just manually iterate through them.
3208 tc->do_thread(VMThread::vm_thread());
3209 Universe::heap()->gc_threads_do(tc);
3210 WatcherThread *wt = WatcherThread::watcher_thread();
3211 // Strictly speaking, the following NULL check isn't sufficient to make sure
3212 // the data for WatcherThread is still valid upon being examined. However,
3213 // considering that WatchThread terminates when the VM is on the way to
3214 // exit at safepoint, the chance of the above is extremely small. The right
3215 // way to prevent termination of WatcherThread would be to acquire
3216 // Terminator_lock, but we can't do that without violating the lock rank
3217 // checking in some cases.
3218 if (wt != NULL) {
3219 tc->do_thread(wt);
3220 }
3221
3222 // If CompilerThreads ever become non-JavaThreads, add them here
3223 }
3224
3225
3226 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3227 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3228
3229 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3230 create_vm_init_libraries();
3231 }
3232
3233 initialize_class(vmSymbols::java_lang_String(), CHECK);
3234
3235 // Initialize java_lang.System (needed before creating the thread)
3236 initialize_class(vmSymbols::java_lang_System(), CHECK);
3237 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3238 Handle thread_group = create_initial_thread_group(CHECK);
3239 Universe::set_main_thread_group(thread_group());
3240 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3241 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3242 main_thread->set_threadObj(thread_object);
3243 // Set thread status to running since main thread has
3244 // been started and running.
3245 java_lang_Thread::set_thread_status(thread_object,
3246 java_lang_Thread::RUNNABLE);
3247
3248 // The VM creates & returns objects of this class. Make sure it's initialized.
3249 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3250
3251 // The VM preresolves methods to these classes. Make sure that they get initialized
3252 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3253 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3254 call_initializeSystemClass(CHECK);
3255
3256 // get the Java runtime name after java.lang.System is initialized
3257 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3258 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3259
3260 // an instance of OutOfMemory exception has been allocated earlier
3261 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3262 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3263 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3264 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3265 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3266 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3267 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3268 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3269 }
3270
3271 void Threads::initialize_jsr292_core_classes(TRAPS) {
3272 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3273 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3274 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3275 }
3276
3277 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3278 extern void JDK_Version_init();
3279
3280 // Check version
3281 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3282
3283 // Initialize the output stream module
3284 ostream_init();
3285
3286 // Process java launcher properties.
3287 Arguments::process_sun_java_launcher_properties(args);
3288
3289 // Initialize the os module before using TLS
3290 os::init();
3291
3292 // Initialize system properties.
3293 Arguments::init_system_properties();
3294
3295 // So that JDK version can be used as a discriminator when parsing arguments
3296 JDK_Version_init();
3297
3298 // Update/Initialize System properties after JDK version number is known
3299 Arguments::init_version_specific_system_properties();
3300
3301 // Parse arguments
3302 jint parse_result = Arguments::parse(args);
3303 if (parse_result != JNI_OK) return parse_result;
3304
3305 os::init_before_ergo();
3306
3307 jint ergo_result = Arguments::apply_ergo();
3308 if (ergo_result != JNI_OK) return ergo_result;
3309
3310 if (PauseAtStartup) {
3311 os::pause();
3312 }
3313
3314 HOTSPOT_VM_INIT_BEGIN();
3315
3316 // Record VM creation timing statistics
3317 TraceVmCreationTime create_vm_timer;
3318 create_vm_timer.start();
3319
3320 // Timing (must come after argument parsing)
3321 TraceTime timer("Create VM", TraceStartupTime);
3322
3323 // Initialize the os module after parsing the args
3324 jint os_init_2_result = os::init_2();
3325 if (os_init_2_result != JNI_OK) return os_init_2_result;
3326
3327 jint adjust_after_os_result = Arguments::adjust_after_os();
3328 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3329
3330 // initialize TLS
3331 ThreadLocalStorage::init();
3332
3333 // Initialize output stream logging
3334 ostream_init_log();
3335
3336 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3337 // Must be before create_vm_init_agents()
3338 if (Arguments::init_libraries_at_startup()) {
3339 convert_vm_init_libraries_to_agents();
3340 }
3341
3342 // Launch -agentlib/-agentpath and converted -Xrun agents
3343 if (Arguments::init_agents_at_startup()) {
3344 create_vm_init_agents();
3345 }
3346
3347 // Initialize Threads state
3348 _thread_list = NULL;
3349 _number_of_threads = 0;
3350 _number_of_non_daemon_threads = 0;
3351
3352 // Initialize global data structures and create system classes in heap
3353 vm_init_globals();
3354
3355 // Attach the main thread to this os thread
3356 JavaThread* main_thread = new JavaThread();
3357 main_thread->set_thread_state(_thread_in_vm);
3358 // must do this before set_active_handles and initialize_thread_local_storage
3359 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3360 // change the stack size recorded here to one based on the java thread
3361 // stacksize. This adjusted size is what is used to figure the placement
3362 // of the guard pages.
3363 main_thread->record_stack_base_and_size();
3364 main_thread->initialize_thread_local_storage();
3365
3366 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3367
3368 if (!main_thread->set_as_starting_thread()) {
3369 vm_shutdown_during_initialization(
3370 "Failed necessary internal allocation. Out of swap space");
3371 delete main_thread;
3372 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3373 return JNI_ENOMEM;
3374 }
3375
3376 // Enable guard page *after* os::create_main_thread(), otherwise it would
3377 // crash Linux VM, see notes in os_linux.cpp.
3378 main_thread->create_stack_guard_pages();
3379
3380 // Initialize Java-Level synchronization subsystem
3381 ObjectMonitor::Initialize();
3382
3383 // Initialize global modules
3384 jint status = init_globals();
3385 if (status != JNI_OK) {
3386 delete main_thread;
3387 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3388 return status;
3389 }
3390
3391 // Should be done after the heap is fully created
3392 main_thread->cache_global_variables();
3393
3394 HandleMark hm;
3395
3396 { MutexLocker mu(Threads_lock);
3397 Threads::add(main_thread);
3398 }
3399
3400 // Any JVMTI raw monitors entered in onload will transition into
3401 // real raw monitor. VM is setup enough here for raw monitor enter.
3402 JvmtiExport::transition_pending_onload_raw_monitors();
3403
3404 // Create the VMThread
3405 { TraceTime timer("Start VMThread", TraceStartupTime);
3406 VMThread::create();
3407 Thread* vmthread = VMThread::vm_thread();
3408
3409 if (!os::create_thread(vmthread, os::vm_thread)) {
3410 vm_exit_during_initialization("Cannot create VM thread. "
3411 "Out of system resources.");
3412 }
3413
3414 // Wait for the VM thread to become ready, and VMThread::run to initialize
3415 // Monitors can have spurious returns, must always check another state flag
3416 {
3417 MutexLocker ml(Notify_lock);
3418 os::start_thread(vmthread);
3419 while (vmthread->active_handles() == NULL) {
3420 Notify_lock->wait();
3421 }
3422 }
3423 }
3424
3425 assert(Universe::is_fully_initialized(), "not initialized");
3426 if (VerifyDuringStartup) {
3427 // Make sure we're starting with a clean slate.
3428 VM_Verify verify_op;
3429 VMThread::execute(&verify_op);
3430 }
3431
3432 Thread* THREAD = Thread::current();
3433
3434 // At this point, the Universe is initialized, but we have not executed
3435 // any byte code. Now is a good time (the only time) to dump out the
3436 // internal state of the JVM for sharing.
3437 if (DumpSharedSpaces) {
3438 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3439 ShouldNotReachHere();
3440 }
3441
3442 // Always call even when there are not JVMTI environments yet, since environments
3443 // may be attached late and JVMTI must track phases of VM execution
3444 JvmtiExport::enter_start_phase();
3445
3446 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3447 JvmtiExport::post_vm_start();
3448
3449 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3450
3451 // We need this for ClassDataSharing - the initial vm.info property is set
3452 // with the default value of CDS "sharing" which may be reset through
3453 // command line options.
3454 reset_vm_info_property(CHECK_JNI_ERR);
3455
3456 quicken_jni_functions();
3457
3458 // Must be run after init_ft which initializes ft_enabled
3459 if (TRACE_INITIALIZE() != JNI_OK) {
3460 vm_exit_during_initialization("Failed to initialize tracing backend");
3461 }
3462
3463 // Set flag that basic initialization has completed. Used by exceptions and various
3464 // debug stuff, that does not work until all basic classes have been initialized.
3465 set_init_completed();
3466
3467 Metaspace::post_initialize();
3468
3469 HOTSPOT_VM_INIT_END();
3470
3471 // record VM initialization completion time
3472 #if INCLUDE_MANAGEMENT
3473 Management::record_vm_init_completed();
3474 #endif // INCLUDE_MANAGEMENT
3475
3476 // Compute system loader. Note that this has to occur after set_init_completed, since
3477 // valid exceptions may be thrown in the process.
3478 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3479 // set_init_completed has just been called, causing exceptions not to be shortcut
3480 // anymore. We call vm_exit_during_initialization directly instead.
3481 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3482
3483 #if INCLUDE_ALL_GCS
3484 // Support for ConcurrentMarkSweep. This should be cleaned up
3485 // and better encapsulated. The ugly nested if test would go away
3486 // once things are properly refactored. XXX YSR
3487 if (UseConcMarkSweepGC || UseG1GC) {
3488 if (UseConcMarkSweepGC) {
3489 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3490 } else {
3491 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3492 }
3493 }
3494 #endif // INCLUDE_ALL_GCS
3495
3496 // Always call even when there are not JVMTI environments yet, since environments
3497 // may be attached late and JVMTI must track phases of VM execution
3498 JvmtiExport::enter_live_phase();
3499
3500 // Signal Dispatcher needs to be started before VMInit event is posted
3501 os::signal_init();
3502
3503 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3504 if (!DisableAttachMechanism) {
3505 AttachListener::vm_start();
3506 if (StartAttachListener || AttachListener::init_at_startup()) {
3507 AttachListener::init();
3508 }
3509 }
3510
3511 // Launch -Xrun agents
3512 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3513 // back-end can launch with -Xdebug -Xrunjdwp.
3514 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3515 create_vm_init_libraries();
3516 }
3517
3518 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3519 JvmtiExport::post_vm_initialized();
3520
3521 if (TRACE_START() != JNI_OK) {
3522 vm_exit_during_initialization("Failed to start tracing backend.");
3523 }
3524
3525 if (CleanChunkPoolAsync) {
3526 Chunk::start_chunk_pool_cleaner_task();
3527 }
3528
3529 // initialize compiler(s)
3530 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3531 CompileBroker::compilation_init();
3532 #endif
3533
3534 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3535 // It is done after compilers are initialized, because otherwise compilations of
3536 // signature polymorphic MH intrinsics can be missed
3537 // (see SystemDictionary::find_method_handle_intrinsic).
3538 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3539
3540 #if INCLUDE_MANAGEMENT
3541 Management::initialize(THREAD);
3542
3543 if (HAS_PENDING_EXCEPTION) {
3544 // management agent fails to start possibly due to
3545 // configuration problem and is responsible for printing
3546 // stack trace if appropriate. Simply exit VM.
3547 vm_exit(1);
3548 }
3549 #endif // INCLUDE_MANAGEMENT
3550
3551 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3552 if (MemProfiling) MemProfiler::engage();
3553 StatSampler::engage();
3554 if (CheckJNICalls) JniPeriodicChecker::engage();
3555
3556 BiasedLocking::init();
3557
3558 #if INCLUDE_RTM_OPT
3559 RTMLockingCounters::init();
3560 #endif
3561
3562 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3563 call_postVMInitHook(THREAD);
3564 // The Java side of PostVMInitHook.run must deal with all
3565 // exceptions and provide means of diagnosis.
3566 if (HAS_PENDING_EXCEPTION) {
3567 CLEAR_PENDING_EXCEPTION;
3568 }
3569 }
3570
3571 {
3572 MutexLocker ml(PeriodicTask_lock);
3573 // Make sure the WatcherThread can be started by WatcherThread::start()
3574 // or by dynamic enrollment.
3575 WatcherThread::make_startable();
3576 // Start up the WatcherThread if there are any periodic tasks
3577 // NOTE: All PeriodicTasks should be registered by now. If they
3578 // aren't, late joiners might appear to start slowly (we might
3579 // take a while to process their first tick).
3580 if (PeriodicTask::num_tasks() > 0) {
3581 WatcherThread::start();
3582 }
3583 }
3584
3585 create_vm_timer.end();
3586 #ifdef ASSERT
3587 _vm_complete = true;
3588 #endif
3589 return JNI_OK;
3590 }
3591
3592 // type for the Agent_OnLoad and JVM_OnLoad entry points
3593 extern "C" {
3594 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3595 }
3596 // Find a command line agent library and return its entry point for
3597 // -agentlib: -agentpath: -Xrun
3598 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3599 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3600 const char *on_load_symbols[],
3601 size_t num_symbol_entries) {
3602 OnLoadEntry_t on_load_entry = NULL;
3603 void *library = NULL;
3604
3605 if (!agent->valid()) {
3606 char buffer[JVM_MAXPATHLEN];
3607 char ebuf[1024] = "";
3608 const char *name = agent->name();
3609 const char *msg = "Could not find agent library ";
3610
3611 // First check to see if agent is statically linked into executable
3612 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3613 library = agent->os_lib();
3614 } else if (agent->is_absolute_path()) {
3615 library = os::dll_load(name, ebuf, sizeof ebuf);
3616 if (library == NULL) {
3617 const char *sub_msg = " in absolute path, with error: ";
3618 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3619 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3620 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3621 // If we can't find the agent, exit.
3622 vm_exit_during_initialization(buf, NULL);
3623 FREE_C_HEAP_ARRAY(char, buf);
3624 }
3625 } else {
3626 // Try to load the agent from the standard dll directory
3627 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3628 name)) {
3629 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3630 }
3631 if (library == NULL) { // Try the local directory
3632 char ns[1] = {0};
3633 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3634 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3635 }
3636 if (library == NULL) {
3637 const char *sub_msg = " on the library path, with error: ";
3638 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3639 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3640 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3641 // If we can't find the agent, exit.
3642 vm_exit_during_initialization(buf, NULL);
3643 FREE_C_HEAP_ARRAY(char, buf);
3644 }
3645 }
3646 }
3647 agent->set_os_lib(library);
3648 agent->set_valid();
3649 }
3650
3651 // Find the OnLoad function.
3652 on_load_entry =
3653 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3654 false,
3655 on_load_symbols,
3656 num_symbol_entries));
3657 return on_load_entry;
3658 }
3659
3660 // Find the JVM_OnLoad entry point
3661 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3662 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3663 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3664 }
3665
3666 // Find the Agent_OnLoad entry point
3667 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3668 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3669 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3670 }
3671
3672 // For backwards compatibility with -Xrun
3673 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3674 // treated like -agentpath:
3675 // Must be called before agent libraries are created
3676 void Threads::convert_vm_init_libraries_to_agents() {
3677 AgentLibrary* agent;
3678 AgentLibrary* next;
3679
3680 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3681 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3682 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3683
3684 // If there is an JVM_OnLoad function it will get called later,
3685 // otherwise see if there is an Agent_OnLoad
3686 if (on_load_entry == NULL) {
3687 on_load_entry = lookup_agent_on_load(agent);
3688 if (on_load_entry != NULL) {
3689 // switch it to the agent list -- so that Agent_OnLoad will be called,
3690 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3691 Arguments::convert_library_to_agent(agent);
3692 } else {
3693 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3694 }
3695 }
3696 }
3697 }
3698
3699 // Create agents for -agentlib: -agentpath: and converted -Xrun
3700 // Invokes Agent_OnLoad
3701 // Called very early -- before JavaThreads exist
3702 void Threads::create_vm_init_agents() {
3703 extern struct JavaVM_ main_vm;
3704 AgentLibrary* agent;
3705
3706 JvmtiExport::enter_onload_phase();
3707
3708 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3709 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3710
3711 if (on_load_entry != NULL) {
3712 // Invoke the Agent_OnLoad function
3713 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3714 if (err != JNI_OK) {
3715 vm_exit_during_initialization("agent library failed to init", agent->name());
3716 }
3717 } else {
3718 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3719 }
3720 }
3721 JvmtiExport::enter_primordial_phase();
3722 }
3723
3724 extern "C" {
3725 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3726 }
3727
3728 void Threads::shutdown_vm_agents() {
3729 // Send any Agent_OnUnload notifications
3730 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3731 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3732 extern struct JavaVM_ main_vm;
3733 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3734
3735 // Find the Agent_OnUnload function.
3736 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3737 os::find_agent_function(agent,
3738 false,
3739 on_unload_symbols,
3740 num_symbol_entries));
3741
3742 // Invoke the Agent_OnUnload function
3743 if (unload_entry != NULL) {
3744 JavaThread* thread = JavaThread::current();
3745 ThreadToNativeFromVM ttn(thread);
3746 HandleMark hm(thread);
3747 (*unload_entry)(&main_vm);
3748 }
3749 }
3750 }
3751
3752 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3753 // Invokes JVM_OnLoad
3754 void Threads::create_vm_init_libraries() {
3755 extern struct JavaVM_ main_vm;
3756 AgentLibrary* agent;
3757
3758 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3759 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3760
3761 if (on_load_entry != NULL) {
3762 // Invoke the JVM_OnLoad function
3763 JavaThread* thread = JavaThread::current();
3764 ThreadToNativeFromVM ttn(thread);
3765 HandleMark hm(thread);
3766 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3767 if (err != JNI_OK) {
3768 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3769 }
3770 } else {
3771 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3772 }
3773 }
3774 }
3775
3776 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3777 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3778
3779 JavaThread* java_thread = NULL;
3780 // Sequential search for now. Need to do better optimization later.
3781 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3782 oop tobj = thread->threadObj();
3783 if (!thread->is_exiting() &&
3784 tobj != NULL &&
3785 java_tid == java_lang_Thread::thread_id(tobj)) {
3786 java_thread = thread;
3787 break;
3788 }
3789 }
3790 return java_thread;
3791 }
3792
3793
3794 // Last thread running calls java.lang.Shutdown.shutdown()
3795 void JavaThread::invoke_shutdown_hooks() {
3796 HandleMark hm(this);
3797
3798 // We could get here with a pending exception, if so clear it now.
3799 if (this->has_pending_exception()) {
3800 this->clear_pending_exception();
3801 }
3802
3803 EXCEPTION_MARK;
3804 Klass* k =
3805 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3806 THREAD);
3807 if (k != NULL) {
3808 // SystemDictionary::resolve_or_null will return null if there was
3809 // an exception. If we cannot load the Shutdown class, just don't
3810 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3811 // and finalizers (if runFinalizersOnExit is set) won't be run.
3812 // Note that if a shutdown hook was registered or runFinalizersOnExit
3813 // was called, the Shutdown class would have already been loaded
3814 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3815 instanceKlassHandle shutdown_klass (THREAD, k);
3816 JavaValue result(T_VOID);
3817 JavaCalls::call_static(&result,
3818 shutdown_klass,
3819 vmSymbols::shutdown_method_name(),
3820 vmSymbols::void_method_signature(),
3821 THREAD);
3822 }
3823 CLEAR_PENDING_EXCEPTION;
3824 }
3825
3826 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3827 // the program falls off the end of main(). Another VM exit path is through
3828 // vm_exit() when the program calls System.exit() to return a value or when
3829 // there is a serious error in VM. The two shutdown paths are not exactly
3830 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3831 // and VM_Exit op at VM level.
3832 //
3833 // Shutdown sequence:
3834 // + Shutdown native memory tracking if it is on
3835 // + Wait until we are the last non-daemon thread to execute
3836 // <-- every thing is still working at this moment -->
3837 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3838 // shutdown hooks, run finalizers if finalization-on-exit
3839 // + Call before_exit(), prepare for VM exit
3840 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3841 // currently the only user of this mechanism is File.deleteOnExit())
3842 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3843 // post thread end and vm death events to JVMTI,
3844 // stop signal thread
3845 // + Call JavaThread::exit(), it will:
3846 // > release JNI handle blocks, remove stack guard pages
3847 // > remove this thread from Threads list
3848 // <-- no more Java code from this thread after this point -->
3849 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3850 // the compiler threads at safepoint
3851 // <-- do not use anything that could get blocked by Safepoint -->
3852 // + Disable tracing at JNI/JVM barriers
3853 // + Set _vm_exited flag for threads that are still running native code
3854 // + Delete this thread
3855 // + Call exit_globals()
3856 // > deletes tty
3857 // > deletes PerfMemory resources
3858 // + Return to caller
3859
3860 bool Threads::destroy_vm() {
3861 JavaThread* thread = JavaThread::current();
3862
3863 #ifdef ASSERT
3864 _vm_complete = false;
3865 #endif
3866 // Wait until we are the last non-daemon thread to execute
3867 { MutexLocker nu(Threads_lock);
3868 while (Threads::number_of_non_daemon_threads() > 1)
3869 // This wait should make safepoint checks, wait without a timeout,
3870 // and wait as a suspend-equivalent condition.
3871 //
3872 // Note: If the FlatProfiler is running and this thread is waiting
3873 // for another non-daemon thread to finish, then the FlatProfiler
3874 // is waiting for the external suspend request on this thread to
3875 // complete. wait_for_ext_suspend_completion() will eventually
3876 // timeout, but that takes time. Making this wait a suspend-
3877 // equivalent condition solves that timeout problem.
3878 //
3879 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3880 Mutex::_as_suspend_equivalent_flag);
3881 }
3882
3883 // Hang forever on exit if we are reporting an error.
3884 if (ShowMessageBoxOnError && is_error_reported()) {
3885 os::infinite_sleep();
3886 }
3887 os::wait_for_keypress_at_exit();
3888
3889 // run Java level shutdown hooks
3890 thread->invoke_shutdown_hooks();
3891
3892 before_exit(thread);
3893
3894 thread->exit(true);
3895
3896 // Stop VM thread.
3897 {
3898 // 4945125 The vm thread comes to a safepoint during exit.
3899 // GC vm_operations can get caught at the safepoint, and the
3900 // heap is unparseable if they are caught. Grab the Heap_lock
3901 // to prevent this. The GC vm_operations will not be able to
3902 // queue until after the vm thread is dead. After this point,
3903 // we'll never emerge out of the safepoint before the VM exits.
3904
3905 MutexLocker ml(Heap_lock);
3906
3907 VMThread::wait_for_vm_thread_exit();
3908 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3909 VMThread::destroy();
3910 }
3911
3912 // clean up ideal graph printers
3913 #if defined(COMPILER2) && !defined(PRODUCT)
3914 IdealGraphPrinter::clean_up();
3915 #endif
3916
3917 // Now, all Java threads are gone except daemon threads. Daemon threads
3918 // running Java code or in VM are stopped by the Safepoint. However,
3919 // daemon threads executing native code are still running. But they
3920 // will be stopped at native=>Java/VM barriers. Note that we can't
3921 // simply kill or suspend them, as it is inherently deadlock-prone.
3922
3923 #ifndef PRODUCT
3924 // disable function tracing at JNI/JVM barriers
3925 TraceJNICalls = false;
3926 TraceJVMCalls = false;
3927 TraceRuntimeCalls = false;
3928 #endif
3929
3930 VM_Exit::set_vm_exited();
3931
3932 notify_vm_shutdown();
3933
3934 delete thread;
3935
3936 // exit_globals() will delete tty
3937 exit_globals();
3938
3939 return true;
3940 }
3941
3942
3943 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3944 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3945 return is_supported_jni_version(version);
3946 }
3947
3948
3949 jboolean Threads::is_supported_jni_version(jint version) {
3950 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3951 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3952 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3953 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3954 return JNI_FALSE;
3955 }
3956
3957
3958 void Threads::add(JavaThread* p, bool force_daemon) {
3959 // The threads lock must be owned at this point
3960 assert_locked_or_safepoint(Threads_lock);
3961
3962 // See the comment for this method in thread.hpp for its purpose and
3963 // why it is called here.
3964 p->initialize_queues();
3965 p->set_next(_thread_list);
3966 _thread_list = p;
3967 _number_of_threads++;
3968 oop threadObj = p->threadObj();
3969 bool daemon = true;
3970 // Bootstrapping problem: threadObj can be null for initial
3971 // JavaThread (or for threads attached via JNI)
3972 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3973 _number_of_non_daemon_threads++;
3974 daemon = false;
3975 }
3976
3977 ThreadService::add_thread(p, daemon);
3978
3979 // Possible GC point.
3980 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
3981 }
3982
3983 void Threads::remove(JavaThread* p) {
3984 // Extra scope needed for Thread_lock, so we can check
3985 // that we do not remove thread without safepoint code notice
3986 { MutexLocker ml(Threads_lock);
3987
3988 assert(includes(p), "p must be present");
3989
3990 JavaThread* current = _thread_list;
3991 JavaThread* prev = NULL;
3992
3993 while (current != p) {
3994 prev = current;
3995 current = current->next();
3996 }
3997
3998 if (prev) {
3999 prev->set_next(current->next());
4000 } else {
4001 _thread_list = p->next();
4002 }
4003 _number_of_threads--;
4004 oop threadObj = p->threadObj();
4005 bool daemon = true;
4006 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4007 _number_of_non_daemon_threads--;
4008 daemon = false;
4009
4010 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4011 // on destroy_vm will wake up.
4012 if (number_of_non_daemon_threads() == 1) {
4013 Threads_lock->notify_all();
4014 }
4015 }
4016 ThreadService::remove_thread(p, daemon);
4017
4018 // Make sure that safepoint code disregard this thread. This is needed since
4019 // the thread might mess around with locks after this point. This can cause it
4020 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4021 // of this thread since it is removed from the queue.
4022 p->set_terminated_value();
4023 } // unlock Threads_lock
4024
4025 // Since Events::log uses a lock, we grab it outside the Threads_lock
4026 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4027 }
4028
4029 // Threads_lock must be held when this is called (or must be called during a safepoint)
4030 bool Threads::includes(JavaThread* p) {
4031 assert(Threads_lock->is_locked(), "sanity check");
4032 ALL_JAVA_THREADS(q) {
4033 if (q == p) {
4034 return true;
4035 }
4036 }
4037 return false;
4038 }
4039
4040 // Operations on the Threads list for GC. These are not explicitly locked,
4041 // but the garbage collector must provide a safe context for them to run.
4042 // In particular, these things should never be called when the Threads_lock
4043 // is held by some other thread. (Note: the Safepoint abstraction also
4044 // uses the Threads_lock to guarantee this property. It also makes sure that
4045 // all threads gets blocked when exiting or starting).
4046
4047 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4048 ALL_JAVA_THREADS(p) {
4049 p->oops_do(f, cld_f, cf);
4050 }
4051 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4052 }
4053
4054 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4055 // Introduce a mechanism allowing parallel threads to claim threads as
4056 // root groups. Overhead should be small enough to use all the time,
4057 // even in sequential code.
4058 SharedHeap* sh = SharedHeap::heap();
4059 // Cannot yet substitute active_workers for n_par_threads
4060 // because of G1CollectedHeap::verify() use of
4061 // SharedHeap::process_roots(). n_par_threads == 0 will
4062 // turn off parallelism in process_roots while active_workers
4063 // is being used for parallelism elsewhere.
4064 bool is_par = sh->n_par_threads() > 0;
4065 assert(!is_par ||
4066 (SharedHeap::heap()->n_par_threads() ==
4067 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4068 int cp = SharedHeap::heap()->strong_roots_parity();
4069 ALL_JAVA_THREADS(p) {
4070 if (p->claim_oops_do(is_par, cp)) {
4071 p->oops_do(f, cld_f, cf);
4072 }
4073 }
4074 VMThread* vmt = VMThread::vm_thread();
4075 if (vmt->claim_oops_do(is_par, cp)) {
4076 vmt->oops_do(f, cld_f, cf);
4077 }
4078 }
4079
4080 #if INCLUDE_ALL_GCS
4081 // Used by ParallelScavenge
4082 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4083 ALL_JAVA_THREADS(p) {
4084 q->enqueue(new ThreadRootsTask(p));
4085 }
4086 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4087 }
4088
4089 // Used by Parallel Old
4090 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4091 ALL_JAVA_THREADS(p) {
4092 q->enqueue(new ThreadRootsMarkingTask(p));
4093 }
4094 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4095 }
4096 #endif // INCLUDE_ALL_GCS
4097
4098 void Threads::nmethods_do(CodeBlobClosure* cf) {
4099 ALL_JAVA_THREADS(p) {
4100 p->nmethods_do(cf);
4101 }
4102 VMThread::vm_thread()->nmethods_do(cf);
4103 }
4104
4105 void Threads::metadata_do(void f(Metadata*)) {
4106 ALL_JAVA_THREADS(p) {
4107 p->metadata_do(f);
4108 }
4109 }
4110
4111 class ThreadHandlesClosure : public ThreadClosure {
4112 void (*_f)(Metadata*);
4113 public:
4114 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4115 virtual void do_thread(Thread* thread) {
4116 thread->metadata_handles_do(_f);
4117 }
4118 };
4119
4120 void Threads::metadata_handles_do(void f(Metadata*)) {
4121 // Only walk the Handles in Thread.
4122 ThreadHandlesClosure handles_closure(f);
4123 threads_do(&handles_closure);
4124 }
4125
4126 void Threads::deoptimized_wrt_marked_nmethods() {
4127 ALL_JAVA_THREADS(p) {
4128 p->deoptimized_wrt_marked_nmethods();
4129 }
4130 }
4131
4132
4133 // Get count Java threads that are waiting to enter the specified monitor.
4134 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4135 address monitor,
4136 bool doLock) {
4137 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4138 "must grab Threads_lock or be at safepoint");
4139 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4140
4141 int i = 0;
4142 {
4143 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4144 ALL_JAVA_THREADS(p) {
4145 if (p->is_Compiler_thread()) continue;
4146
4147 address pending = (address)p->current_pending_monitor();
4148 if (pending == monitor) { // found a match
4149 if (i < count) result->append(p); // save the first count matches
4150 i++;
4151 }
4152 }
4153 }
4154 return result;
4155 }
4156
4157
4158 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4159 bool doLock) {
4160 assert(doLock ||
4161 Threads_lock->owned_by_self() ||
4162 SafepointSynchronize::is_at_safepoint(),
4163 "must grab Threads_lock or be at safepoint");
4164
4165 // NULL owner means not locked so we can skip the search
4166 if (owner == NULL) return NULL;
4167
4168 {
4169 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4170 ALL_JAVA_THREADS(p) {
4171 // first, see if owner is the address of a Java thread
4172 if (owner == (address)p) return p;
4173 }
4174 }
4175 // Cannot assert on lack of success here since this function may be
4176 // used by code that is trying to report useful problem information
4177 // like deadlock detection.
4178 if (UseHeavyMonitors) return NULL;
4179
4180 // If we didn't find a matching Java thread and we didn't force use of
4181 // heavyweight monitors, then the owner is the stack address of the
4182 // Lock Word in the owning Java thread's stack.
4183 //
4184 JavaThread* the_owner = NULL;
4185 {
4186 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4187 ALL_JAVA_THREADS(q) {
4188 if (q->is_lock_owned(owner)) {
4189 the_owner = q;
4190 break;
4191 }
4192 }
4193 }
4194 // cannot assert on lack of success here; see above comment
4195 return the_owner;
4196 }
4197
4198 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4199 void Threads::print_on(outputStream* st, bool print_stacks,
4200 bool internal_format, bool print_concurrent_locks) {
4201 char buf[32];
4202 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4203
4204 st->print_cr("Full thread dump %s (%s %s):",
4205 Abstract_VM_Version::vm_name(),
4206 Abstract_VM_Version::vm_release(),
4207 Abstract_VM_Version::vm_info_string());
4208 st->cr();
4209
4210 #if INCLUDE_ALL_GCS
4211 // Dump concurrent locks
4212 ConcurrentLocksDump concurrent_locks;
4213 if (print_concurrent_locks) {
4214 concurrent_locks.dump_at_safepoint();
4215 }
4216 #endif // INCLUDE_ALL_GCS
4217
4218 ALL_JAVA_THREADS(p) {
4219 ResourceMark rm;
4220 p->print_on(st);
4221 if (print_stacks) {
4222 if (internal_format) {
4223 p->trace_stack();
4224 } else {
4225 p->print_stack_on(st);
4226 }
4227 }
4228 st->cr();
4229 #if INCLUDE_ALL_GCS
4230 if (print_concurrent_locks) {
4231 concurrent_locks.print_locks_on(p, st);
4232 }
4233 #endif // INCLUDE_ALL_GCS
4234 }
4235
4236 VMThread::vm_thread()->print_on(st);
4237 st->cr();
4238 Universe::heap()->print_gc_threads_on(st);
4239 WatcherThread* wt = WatcherThread::watcher_thread();
4240 if (wt != NULL) {
4241 wt->print_on(st);
4242 st->cr();
4243 }
4244 CompileBroker::print_compiler_threads_on(st);
4245 st->flush();
4246 }
4247
4248 // Threads::print_on_error() is called by fatal error handler. It's possible
4249 // that VM is not at safepoint and/or current thread is inside signal handler.
4250 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4251 // memory (even in resource area), it might deadlock the error handler.
4252 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4253 int buflen) {
4254 bool found_current = false;
4255 st->print_cr("Java Threads: ( => current thread )");
4256 ALL_JAVA_THREADS(thread) {
4257 bool is_current = (current == thread);
4258 found_current = found_current || is_current;
4259
4260 st->print("%s", is_current ? "=>" : " ");
4261
4262 st->print(PTR_FORMAT, thread);
4263 st->print(" ");
4264 thread->print_on_error(st, buf, buflen);
4265 st->cr();
4266 }
4267 st->cr();
4268
4269 st->print_cr("Other Threads:");
4270 if (VMThread::vm_thread()) {
4271 bool is_current = (current == VMThread::vm_thread());
4272 found_current = found_current || is_current;
4273 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4274
4275 st->print(PTR_FORMAT, VMThread::vm_thread());
4276 st->print(" ");
4277 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4278 st->cr();
4279 }
4280 WatcherThread* wt = WatcherThread::watcher_thread();
4281 if (wt != NULL) {
4282 bool is_current = (current == wt);
4283 found_current = found_current || is_current;
4284 st->print("%s", is_current ? "=>" : " ");
4285
4286 st->print(PTR_FORMAT, wt);
4287 st->print(" ");
4288 wt->print_on_error(st, buf, buflen);
4289 st->cr();
4290 }
4291 if (!found_current) {
4292 st->cr();
4293 st->print("=>" PTR_FORMAT " (exited) ", current);
4294 current->print_on_error(st, buf, buflen);
4295 st->cr();
4296 }
4297 }
4298
4299 // Internal SpinLock and Mutex
4300 // Based on ParkEvent
4301
4302 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4303 //
4304 // We employ SpinLocks _only for low-contention, fixed-length
4305 // short-duration critical sections where we're concerned
4306 // about native mutex_t or HotSpot Mutex:: latency.
4307 // The mux construct provides a spin-then-block mutual exclusion
4308 // mechanism.
4309 //
4310 // Testing has shown that contention on the ListLock guarding gFreeList
4311 // is common. If we implement ListLock as a simple SpinLock it's common
4312 // for the JVM to devolve to yielding with little progress. This is true
4313 // despite the fact that the critical sections protected by ListLock are
4314 // extremely short.
4315 //
4316 // TODO-FIXME: ListLock should be of type SpinLock.
4317 // We should make this a 1st-class type, integrated into the lock
4318 // hierarchy as leaf-locks. Critically, the SpinLock structure
4319 // should have sufficient padding to avoid false-sharing and excessive
4320 // cache-coherency traffic.
4321
4322
4323 typedef volatile int SpinLockT;
4324
4325 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4326 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4327 return; // normal fast-path return
4328 }
4329
4330 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4331 TEVENT(SpinAcquire - ctx);
4332 int ctr = 0;
4333 int Yields = 0;
4334 for (;;) {
4335 while (*adr != 0) {
4336 ++ctr;
4337 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4338 if (Yields > 5) {
4339 os::naked_short_sleep(1);
4340 } else {
4341 os::naked_yield();
4342 ++Yields;
4343 }
4344 } else {
4345 SpinPause();
4346 }
4347 }
4348 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4349 }
4350 }
4351
4352 void Thread::SpinRelease(volatile int * adr) {
4353 assert(*adr != 0, "invariant");
4354 OrderAccess::fence(); // guarantee at least release consistency.
4355 // Roach-motel semantics.
4356 // It's safe if subsequent LDs and STs float "up" into the critical section,
4357 // but prior LDs and STs within the critical section can't be allowed
4358 // to reorder or float past the ST that releases the lock.
4359 // Loads and stores in the critical section - which appear in program
4360 // order before the store that releases the lock - must also appear
4361 // before the store that releases the lock in memory visibility order.
4362 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4363 // the ST of 0 into the lock-word which releases the lock, so fence
4364 // more than covers this on all platforms.
4365 *adr = 0;
4366 }
4367
4368 // muxAcquire and muxRelease:
4369 //
4370 // * muxAcquire and muxRelease support a single-word lock-word construct.
4371 // The LSB of the word is set IFF the lock is held.
4372 // The remainder of the word points to the head of a singly-linked list
4373 // of threads blocked on the lock.
4374 //
4375 // * The current implementation of muxAcquire-muxRelease uses its own
4376 // dedicated Thread._MuxEvent instance. If we're interested in
4377 // minimizing the peak number of extant ParkEvent instances then
4378 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4379 // as certain invariants were satisfied. Specifically, care would need
4380 // to be taken with regards to consuming unpark() "permits".
4381 // A safe rule of thumb is that a thread would never call muxAcquire()
4382 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4383 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4384 // consume an unpark() permit intended for monitorenter, for instance.
4385 // One way around this would be to widen the restricted-range semaphore
4386 // implemented in park(). Another alternative would be to provide
4387 // multiple instances of the PlatformEvent() for each thread. One
4388 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4389 //
4390 // * Usage:
4391 // -- Only as leaf locks
4392 // -- for short-term locking only as muxAcquire does not perform
4393 // thread state transitions.
4394 //
4395 // Alternatives:
4396 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4397 // but with parking or spin-then-park instead of pure spinning.
4398 // * Use Taura-Oyama-Yonenzawa locks.
4399 // * It's possible to construct a 1-0 lock if we encode the lockword as
4400 // (List,LockByte). Acquire will CAS the full lockword while Release
4401 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4402 // acquiring threads use timers (ParkTimed) to detect and recover from
4403 // the stranding window. Thread/Node structures must be aligned on 256-byte
4404 // boundaries by using placement-new.
4405 // * Augment MCS with advisory back-link fields maintained with CAS().
4406 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4407 // The validity of the backlinks must be ratified before we trust the value.
4408 // If the backlinks are invalid the exiting thread must back-track through the
4409 // the forward links, which are always trustworthy.
4410 // * Add a successor indication. The LockWord is currently encoded as
4411 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4412 // to provide the usual futile-wakeup optimization.
4413 // See RTStt for details.
4414 // * Consider schedctl.sc_nopreempt to cover the critical section.
4415 //
4416
4417
4418 typedef volatile intptr_t MutexT; // Mux Lock-word
4419 enum MuxBits { LOCKBIT = 1 };
4420
4421 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4422 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4423 if (w == 0) return;
4424 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4425 return;
4426 }
4427
4428 TEVENT(muxAcquire - Contention);
4429 ParkEvent * const Self = Thread::current()->_MuxEvent;
4430 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4431 for (;;) {
4432 int its = (os::is_MP() ? 100 : 0) + 1;
4433
4434 // Optional spin phase: spin-then-park strategy
4435 while (--its >= 0) {
4436 w = *Lock;
4437 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4438 return;
4439 }
4440 }
4441
4442 Self->reset();
4443 Self->OnList = intptr_t(Lock);
4444 // The following fence() isn't _strictly necessary as the subsequent
4445 // CAS() both serializes execution and ratifies the fetched *Lock value.
4446 OrderAccess::fence();
4447 for (;;) {
4448 w = *Lock;
4449 if ((w & LOCKBIT) == 0) {
4450 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4451 Self->OnList = 0; // hygiene - allows stronger asserts
4452 return;
4453 }
4454 continue; // Interference -- *Lock changed -- Just retry
4455 }
4456 assert(w & LOCKBIT, "invariant");
4457 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4458 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4459 }
4460
4461 while (Self->OnList != 0) {
4462 Self->park();
4463 }
4464 }
4465 }
4466
4467 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4468 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4469 if (w == 0) return;
4470 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4471 return;
4472 }
4473
4474 TEVENT(muxAcquire - Contention);
4475 ParkEvent * ReleaseAfter = NULL;
4476 if (ev == NULL) {
4477 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4478 }
4479 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4480 for (;;) {
4481 guarantee(ev->OnList == 0, "invariant");
4482 int its = (os::is_MP() ? 100 : 0) + 1;
4483
4484 // Optional spin phase: spin-then-park strategy
4485 while (--its >= 0) {
4486 w = *Lock;
4487 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4488 if (ReleaseAfter != NULL) {
4489 ParkEvent::Release(ReleaseAfter);
4490 }
4491 return;
4492 }
4493 }
4494
4495 ev->reset();
4496 ev->OnList = intptr_t(Lock);
4497 // The following fence() isn't _strictly necessary as the subsequent
4498 // CAS() both serializes execution and ratifies the fetched *Lock value.
4499 OrderAccess::fence();
4500 for (;;) {
4501 w = *Lock;
4502 if ((w & LOCKBIT) == 0) {
4503 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4504 ev->OnList = 0;
4505 // We call ::Release while holding the outer lock, thus
4506 // artificially lengthening the critical section.
4507 // Consider deferring the ::Release() until the subsequent unlock(),
4508 // after we've dropped the outer lock.
4509 if (ReleaseAfter != NULL) {
4510 ParkEvent::Release(ReleaseAfter);
4511 }
4512 return;
4513 }
4514 continue; // Interference -- *Lock changed -- Just retry
4515 }
4516 assert(w & LOCKBIT, "invariant");
4517 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4518 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4519 }
4520
4521 while (ev->OnList != 0) {
4522 ev->park();
4523 }
4524 }
4525 }
4526
4527 // Release() must extract a successor from the list and then wake that thread.
4528 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4529 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4530 // Release() would :
4531 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4532 // (B) Extract a successor from the private list "in-hand"
4533 // (C) attempt to CAS() the residual back into *Lock over null.
4534 // If there were any newly arrived threads and the CAS() would fail.
4535 // In that case Release() would detach the RATs, re-merge the list in-hand
4536 // with the RATs and repeat as needed. Alternately, Release() might
4537 // detach and extract a successor, but then pass the residual list to the wakee.
4538 // The wakee would be responsible for reattaching and remerging before it
4539 // competed for the lock.
4540 //
4541 // Both "pop" and DMR are immune from ABA corruption -- there can be
4542 // multiple concurrent pushers, but only one popper or detacher.
4543 // This implementation pops from the head of the list. This is unfair,
4544 // but tends to provide excellent throughput as hot threads remain hot.
4545 // (We wake recently run threads first).
4546 //
4547 // All paths through muxRelease() will execute a CAS.
4548 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4549 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4550 // executed within the critical section are complete and globally visible before the
4551 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4552 void Thread::muxRelease(volatile intptr_t * Lock) {
4553 for (;;) {
4554 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4555 assert(w & LOCKBIT, "invariant");
4556 if (w == LOCKBIT) return;
4557 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4558 assert(List != NULL, "invariant");
4559 assert(List->OnList == intptr_t(Lock), "invariant");
4560 ParkEvent * const nxt = List->ListNext;
4561 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4562
4563 // The following CAS() releases the lock and pops the head element.
4564 // The CAS() also ratifies the previously fetched lock-word value.
4565 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4566 continue;
4567 }
4568 List->OnList = 0;
4569 OrderAccess::fence();
4570 List->unpark();
4571 return;
4572 }
4573 }
4574
4575
4576 void Threads::verify() {
4577 ALL_JAVA_THREADS(p) {
4578 p->verify();
4579 }
4580 VMThread* thread = VMThread::vm_thread();
4581 if (thread != NULL) thread->verify();
4582 }