1 /*
2 * Copyright (c) 1997, 2014, 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 "prims/jvm_misc.hpp"
46 #include "prims/jvmtiExport.hpp"
47 #include "prims/jvmtiThreadState.hpp"
48 #include "prims/privilegedStack.hpp"
49 #include "runtime/arguments.hpp"
50 #include "runtime/atomic.inline.hpp"
51 #include "runtime/biasedLocking.hpp"
52 #include "runtime/deoptimization.hpp"
53 #include "runtime/fprofiler.hpp"
54 #include "runtime/frame.inline.hpp"
55 #include "runtime/init.hpp"
56 #include "runtime/interfaceSupport.hpp"
57 #include "runtime/java.hpp"
58 #include "runtime/javaCalls.hpp"
59 #include "runtime/jniPeriodicChecker.hpp"
60 #include "runtime/memprofiler.hpp"
61 #include "runtime/mutexLocker.hpp"
62 #include "runtime/objectMonitor.hpp"
63 #include "runtime/orderAccess.inline.hpp"
64 #include "runtime/osThread.hpp"
65 #include "runtime/safepoint.hpp"
66 #include "runtime/sharedRuntime.hpp"
67 #include "runtime/statSampler.hpp"
68 #include "runtime/stubRoutines.hpp"
69 #include "runtime/sweeper.hpp"
70 #include "runtime/task.hpp"
71 #include "runtime/thread.inline.hpp"
72 #include "runtime/threadCritical.hpp"
73 #include "runtime/threadLocalStorage.hpp"
74 #include "runtime/vframe.hpp"
75 #include "runtime/vframeArray.hpp"
76 #include "runtime/vframe_hp.hpp"
77 #include "runtime/vmThread.hpp"
78 #include "runtime/vm_operations.hpp"
79 #include "runtime/vm_version.hpp"
80 #include "services/attachListener.hpp"
81 #include "services/management.hpp"
82 #include "services/memTracker.hpp"
83 #include "services/threadService.hpp"
84 #include "trace/tracing.hpp"
85 #include "trace/traceMacros.hpp"
86 #include "utilities/defaultStream.hpp"
87 #include "utilities/dtrace.hpp"
88 #include "utilities/events.hpp"
89 #include "utilities/preserveException.hpp"
90 #include "utilities/macros.hpp"
91 #if INCLUDE_ALL_GCS
92 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
93 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
94 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
95 #endif // INCLUDE_ALL_GCS
96 #ifdef COMPILER1
97 #include "c1/c1_Compiler.hpp"
98 #endif
99 #ifdef COMPILER2
100 #include "opto/c2compiler.hpp"
101 #include "opto/idealGraphPrinter.hpp"
102 #endif
103 #if INCLUDE_RTM_OPT
104 #include "runtime/rtmLocking.hpp"
105 #endif
106
107 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
108
109 #ifdef DTRACE_ENABLED
110
111 // Only bother with this argument setup if dtrace is available
112
113 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
114 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
115
116 #define DTRACE_THREAD_PROBE(probe, javathread) \
117 { \
118 ResourceMark rm(this); \
119 int len = 0; \
120 const char* name = (javathread)->get_thread_name(); \
121 len = strlen(name); \
122 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
123 (char *) name, len, \
124 java_lang_Thread::thread_id((javathread)->threadObj()), \
125 (uintptr_t) (javathread)->osthread()->thread_id(), \
126 java_lang_Thread::is_daemon((javathread)->threadObj())); \
127 }
128
129 #else // ndef DTRACE_ENABLED
130
131 #define DTRACE_THREAD_PROBE(probe, javathread)
132
133 #endif // ndef DTRACE_ENABLED
134
135
136 // Class hierarchy
137 // - Thread
138 // - VMThread
139 // - WatcherThread
140 // - ConcurrentMarkSweepThread
141 // - JavaThread
142 // - CompilerThread
143
144 // ======= Thread ========
145 // Support for forcing alignment of thread objects for biased locking
146 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
147 if (UseBiasedLocking) {
148 const int alignment = markOopDesc::biased_lock_alignment;
149 size_t aligned_size = size + (alignment - sizeof(intptr_t));
150 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
151 : AllocateHeap(aligned_size, flags, CURRENT_PC,
152 AllocFailStrategy::RETURN_NULL);
153 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
154 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
155 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
156 "JavaThread alignment code overflowed allocated storage");
157 if (TraceBiasedLocking) {
158 if (aligned_addr != real_malloc_addr) {
159 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
160 real_malloc_addr, aligned_addr);
161 }
162 }
163 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
164 return aligned_addr;
165 } else {
166 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
167 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
168 }
169 }
170
171 void Thread::operator delete(void* p) {
172 if (UseBiasedLocking) {
173 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
174 FreeHeap(real_malloc_addr, mtThread);
175 } else {
176 FreeHeap(p, mtThread);
177 }
178 }
179
180
181 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
182 // JavaThread
183
184
185 Thread::Thread() {
186 // stack and get_thread
187 set_stack_base(NULL);
188 set_stack_size(0);
189 set_self_raw_id(0);
190 set_lgrp_id(-1);
191
192 // allocated data structures
193 set_osthread(NULL);
194 set_resource_area(new (mtThread)ResourceArea());
195 DEBUG_ONLY(_current_resource_mark = NULL;)
196 set_handle_area(new (mtThread) HandleArea(NULL));
197 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
198 set_active_handles(NULL);
199 set_free_handle_block(NULL);
200 set_last_handle_mark(NULL);
201
202 // This initial value ==> never claimed.
203 _oops_do_parity = 0;
204
205 _metadata_on_stack_buffer = NULL;
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 _suspend_flags = 0;
235
236 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
237 _hashStateX = os::random();
238 _hashStateY = 842502087;
239 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
240 _hashStateW = 273326509;
241
242 _OnTrap = 0;
243 _schedctl = NULL;
244 _Stalled = 0;
245 _TypeTag = 0x2BAD;
246
247 // Many of the following fields are effectively final - immutable
248 // Note that nascent threads can't use the Native Monitor-Mutex
249 // construct until the _MutexEvent is initialized ...
250 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
251 // we might instead use a stack of ParkEvents that we could provision on-demand.
252 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
253 // and ::Release()
254 _ParkEvent = ParkEvent::Allocate(this);
255 _SleepEvent = ParkEvent::Allocate(this);
256 _MutexEvent = ParkEvent::Allocate(this);
257 _MuxEvent = ParkEvent::Allocate(this);
258
259 #ifdef CHECK_UNHANDLED_OOPS
260 if (CheckUnhandledOops) {
261 _unhandled_oops = new UnhandledOops(this);
262 }
263 #endif // CHECK_UNHANDLED_OOPS
264 #ifdef ASSERT
265 if (UseBiasedLocking) {
266 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
267 assert(this == _real_malloc_address ||
268 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
269 "bug in forced alignment of thread objects");
270 }
271 #endif // ASSERT
272 }
273
274 void Thread::initialize_thread_local_storage() {
275 // Note: Make sure this method only calls
276 // non-blocking operations. Otherwise, it might not work
277 // with the thread-startup/safepoint interaction.
278
279 // During Java thread startup, safepoint code should allow this
280 // method to complete because it may need to allocate memory to
281 // store information for the new thread.
282
283 // initialize structure dependent on thread local storage
284 ThreadLocalStorage::set_thread(this);
285 }
286
287 void Thread::record_stack_base_and_size() {
288 set_stack_base(os::current_stack_base());
289 set_stack_size(os::current_stack_size());
290 if (is_Java_thread()) {
291 ((JavaThread*) this)->set_stack_overflow_limit();
292 }
293 // CR 7190089: on Solaris, primordial thread's stack is adjusted
294 // in initialize_thread(). Without the adjustment, stack size is
295 // incorrect if stack is set to unlimited (ulimit -s unlimited).
296 // So far, only Solaris has real implementation of initialize_thread().
297 //
298 // set up any platform-specific state.
299 os::initialize_thread(this);
300
301 #if INCLUDE_NMT
302 // record thread's native stack, stack grows downward
303 address stack_low_addr = stack_base() - stack_size();
304 MemTracker::record_thread_stack(stack_low_addr, stack_size());
305 #endif // INCLUDE_NMT
306 }
307
308
309 Thread::~Thread() {
310 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
311 ObjectSynchronizer::omFlush(this);
312
313 EVENT_THREAD_DESTRUCT(this);
314
315 // stack_base can be NULL if the thread is never started or exited before
316 // record_stack_base_and_size called. Although, we would like to ensure
317 // that all started threads do call record_stack_base_and_size(), there is
318 // not proper way to enforce that.
319 #if INCLUDE_NMT
320 if (_stack_base != NULL) {
321 address low_stack_addr = stack_base() - stack_size();
322 MemTracker::release_thread_stack(low_stack_addr, stack_size());
323 #ifdef ASSERT
324 set_stack_base(NULL);
325 #endif
326 }
327 #endif // INCLUDE_NMT
328
329 // deallocate data structures
330 delete resource_area();
331 // since the handle marks are using the handle area, we have to deallocated the root
332 // handle mark before deallocating the thread's handle area,
333 assert(last_handle_mark() != NULL, "check we have an element");
334 delete last_handle_mark();
335 assert(last_handle_mark() == NULL, "check we have reached the end");
336
337 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
338 // We NULL out the fields for good hygiene.
339 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
340 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
341 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
342 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
343
344 delete handle_area();
345 delete metadata_handles();
346
347 // osthread() can be NULL, if creation of thread failed.
348 if (osthread() != NULL) os::free_thread(osthread());
349
350 delete _SR_lock;
351
352 // clear thread local storage if the Thread is deleting itself
353 if (this == Thread::current()) {
354 ThreadLocalStorage::set_thread(NULL);
355 } else {
356 // In the case where we're not the current thread, invalidate all the
357 // caches in case some code tries to get the current thread or the
358 // thread that was destroyed, and gets stale information.
359 ThreadLocalStorage::invalidate_all();
360 }
361 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
362 }
363
364 // NOTE: dummy function for assertion purpose.
365 void Thread::run() {
366 ShouldNotReachHere();
367 }
368
369 #ifdef ASSERT
370 // Private method to check for dangling thread pointer
371 void check_for_dangling_thread_pointer(Thread *thread) {
372 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
373 "possibility of dangling Thread pointer");
374 }
375 #endif
376
377
378 #ifndef PRODUCT
379 // Tracing method for basic thread operations
380 void Thread::trace(const char* msg, const Thread* const thread) {
381 if (!TraceThreadEvents) return;
382 ResourceMark rm;
383 ThreadCritical tc;
384 const char *name = "non-Java thread";
385 int prio = -1;
386 if (thread->is_Java_thread()
387 && !thread->is_Compiler_thread()) {
388 // The Threads_lock must be held to get information about
389 // this thread but may not be in some situations when
390 // tracing thread events.
391 bool release_Threads_lock = false;
392 if (!Threads_lock->owned_by_self()) {
393 Threads_lock->lock();
394 release_Threads_lock = true;
395 }
396 JavaThread* jt = (JavaThread *)thread;
397 name = (char *)jt->get_thread_name();
398 oop thread_oop = jt->threadObj();
399 if (thread_oop != NULL) {
400 prio = java_lang_Thread::priority(thread_oop);
401 }
402 if (release_Threads_lock) {
403 Threads_lock->unlock();
404 }
405 }
406 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
407 }
408 #endif
409
410
411 ThreadPriority Thread::get_priority(const Thread* const thread) {
412 trace("get priority", thread);
413 ThreadPriority priority;
414 // Can return an error!
415 (void)os::get_priority(thread, priority);
416 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
417 return priority;
418 }
419
420 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
421 trace("set priority", thread);
422 debug_only(check_for_dangling_thread_pointer(thread);)
423 // Can return an error!
424 (void)os::set_priority(thread, priority);
425 }
426
427
428 void Thread::start(Thread* thread) {
429 trace("start", thread);
430 // Start is different from resume in that its safety is guaranteed by context or
431 // being called from a Java method synchronized on the Thread object.
432 if (!DisableStartThread) {
433 if (thread->is_Java_thread()) {
434 // Initialize the thread state to RUNNABLE before starting this thread.
435 // Can not set it after the thread started because we do not know the
436 // exact thread state at that time. It could be in MONITOR_WAIT or
437 // in SLEEPING or some other state.
438 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
439 java_lang_Thread::RUNNABLE);
440 }
441 os::start_thread(thread);
442 }
443 }
444
445 // Enqueue a VM_Operation to do the job for us - sometime later
446 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
447 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
448 VMThread::execute(vm_stop);
449 }
450
451
452 // Check if an external suspend request has completed (or has been
453 // cancelled). Returns true if the thread is externally suspended and
454 // false otherwise.
455 //
456 // The bits parameter returns information about the code path through
457 // the routine. Useful for debugging:
458 //
459 // set in is_ext_suspend_completed():
460 // 0x00000001 - routine was entered
461 // 0x00000010 - routine return false at end
462 // 0x00000100 - thread exited (return false)
463 // 0x00000200 - suspend request cancelled (return false)
464 // 0x00000400 - thread suspended (return true)
465 // 0x00001000 - thread is in a suspend equivalent state (return true)
466 // 0x00002000 - thread is native and walkable (return true)
467 // 0x00004000 - thread is native_trans and walkable (needed retry)
468 //
469 // set in wait_for_ext_suspend_completion():
470 // 0x00010000 - routine was entered
471 // 0x00020000 - suspend request cancelled before loop (return false)
472 // 0x00040000 - thread suspended before loop (return true)
473 // 0x00080000 - suspend request cancelled in loop (return false)
474 // 0x00100000 - thread suspended in loop (return true)
475 // 0x00200000 - suspend not completed during retry loop (return false)
476
477 // Helper class for tracing suspend wait debug bits.
478 //
479 // 0x00000100 indicates that the target thread exited before it could
480 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
481 // 0x00080000 each indicate a cancelled suspend request so they don't
482 // count as wait failures either.
483 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
484
485 class TraceSuspendDebugBits : public StackObj {
486 private:
487 JavaThread * jt;
488 bool is_wait;
489 bool called_by_wait; // meaningful when !is_wait
490 uint32_t * bits;
491
492 public:
493 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
494 uint32_t *_bits) {
495 jt = _jt;
496 is_wait = _is_wait;
497 called_by_wait = _called_by_wait;
498 bits = _bits;
499 }
500
501 ~TraceSuspendDebugBits() {
502 if (!is_wait) {
503 #if 1
504 // By default, don't trace bits for is_ext_suspend_completed() calls.
505 // That trace is very chatty.
506 return;
507 #else
508 if (!called_by_wait) {
509 // If tracing for is_ext_suspend_completed() is enabled, then only
510 // trace calls to it from wait_for_ext_suspend_completion()
511 return;
512 }
513 #endif
514 }
515
516 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
517 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
518 MutexLocker ml(Threads_lock); // needed for get_thread_name()
519 ResourceMark rm;
520
521 tty->print_cr(
522 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
523 jt->get_thread_name(), *bits);
524
525 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
526 }
527 }
528 }
529 };
530 #undef DEBUG_FALSE_BITS
531
532
533 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
534 uint32_t *bits) {
535 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
536
537 bool did_trans_retry = false; // only do thread_in_native_trans retry once
538 bool do_trans_retry; // flag to force the retry
539
540 *bits |= 0x00000001;
541
542 do {
543 do_trans_retry = false;
544
545 if (is_exiting()) {
546 // Thread is in the process of exiting. This is always checked
547 // first to reduce the risk of dereferencing a freed JavaThread.
548 *bits |= 0x00000100;
549 return false;
550 }
551
552 if (!is_external_suspend()) {
553 // Suspend request is cancelled. This is always checked before
554 // is_ext_suspended() to reduce the risk of a rogue resume
555 // confusing the thread that made the suspend request.
556 *bits |= 0x00000200;
557 return false;
558 }
559
560 if (is_ext_suspended()) {
561 // thread is suspended
562 *bits |= 0x00000400;
563 return true;
564 }
565
566 // Now that we no longer do hard suspends of threads running
567 // native code, the target thread can be changing thread state
568 // while we are in this routine:
569 //
570 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
571 //
572 // We save a copy of the thread state as observed at this moment
573 // and make our decision about suspend completeness based on the
574 // copy. This closes the race where the thread state is seen as
575 // _thread_in_native_trans in the if-thread_blocked check, but is
576 // seen as _thread_blocked in if-thread_in_native_trans check.
577 JavaThreadState save_state = thread_state();
578
579 if (save_state == _thread_blocked && is_suspend_equivalent()) {
580 // If the thread's state is _thread_blocked and this blocking
581 // condition is known to be equivalent to a suspend, then we can
582 // consider the thread to be externally suspended. This means that
583 // the code that sets _thread_blocked has been modified to do
584 // self-suspension if the blocking condition releases. We also
585 // used to check for CONDVAR_WAIT here, but that is now covered by
586 // the _thread_blocked with self-suspension check.
587 //
588 // Return true since we wouldn't be here unless there was still an
589 // external suspend request.
590 *bits |= 0x00001000;
591 return true;
592 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
593 // Threads running native code will self-suspend on native==>VM/Java
594 // transitions. If its stack is walkable (should always be the case
595 // unless this function is called before the actual java_suspend()
596 // call), then the wait is done.
597 *bits |= 0x00002000;
598 return true;
599 } else if (!called_by_wait && !did_trans_retry &&
600 save_state == _thread_in_native_trans &&
601 frame_anchor()->walkable()) {
602 // The thread is transitioning from thread_in_native to another
603 // thread state. check_safepoint_and_suspend_for_native_trans()
604 // will force the thread to self-suspend. If it hasn't gotten
605 // there yet we may have caught the thread in-between the native
606 // code check above and the self-suspend. Lucky us. If we were
607 // called by wait_for_ext_suspend_completion(), then it
608 // will be doing the retries so we don't have to.
609 //
610 // Since we use the saved thread state in the if-statement above,
611 // there is a chance that the thread has already transitioned to
612 // _thread_blocked by the time we get here. In that case, we will
613 // make a single unnecessary pass through the logic below. This
614 // doesn't hurt anything since we still do the trans retry.
615
616 *bits |= 0x00004000;
617
618 // Once the thread leaves thread_in_native_trans for another
619 // thread state, we break out of this retry loop. We shouldn't
620 // need this flag to prevent us from getting back here, but
621 // sometimes paranoia is good.
622 did_trans_retry = true;
623
624 // We wait for the thread to transition to a more usable state.
625 for (int i = 1; i <= SuspendRetryCount; i++) {
626 // We used to do an "os::yield_all(i)" call here with the intention
627 // that yielding would increase on each retry. However, the parameter
628 // is ignored on Linux which means the yield didn't scale up. Waiting
629 // on the SR_lock below provides a much more predictable scale up for
630 // the delay. It also provides a simple/direct point to check for any
631 // safepoint requests from the VMThread
632
633 // temporarily drops SR_lock while doing wait with safepoint check
634 // (if we're a JavaThread - the WatcherThread can also call this)
635 // and increase delay with each retry
636 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
637
638 // check the actual thread state instead of what we saved above
639 if (thread_state() != _thread_in_native_trans) {
640 // the thread has transitioned to another thread state so
641 // try all the checks (except this one) one more time.
642 do_trans_retry = true;
643 break;
644 }
645 } // end retry loop
646
647
648 }
649 } while (do_trans_retry);
650
651 *bits |= 0x00000010;
652 return false;
653 }
654
655 // Wait for an external suspend request to complete (or be cancelled).
656 // Returns true if the thread is externally suspended and false otherwise.
657 //
658 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
659 uint32_t *bits) {
660 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
661 false /* !called_by_wait */, bits);
662
663 // local flag copies to minimize SR_lock hold time
664 bool is_suspended;
665 bool pending;
666 uint32_t reset_bits;
667
668 // set a marker so is_ext_suspend_completed() knows we are the caller
669 *bits |= 0x00010000;
670
671 // We use reset_bits to reinitialize the bits value at the top of
672 // each retry loop. This allows the caller to make use of any
673 // unused bits for their own marking purposes.
674 reset_bits = *bits;
675
676 {
677 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
678 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
679 delay, bits);
680 pending = is_external_suspend();
681 }
682 // must release SR_lock to allow suspension to complete
683
684 if (!pending) {
685 // A cancelled suspend request is the only false return from
686 // is_ext_suspend_completed() that keeps us from entering the
687 // retry loop.
688 *bits |= 0x00020000;
689 return false;
690 }
691
692 if (is_suspended) {
693 *bits |= 0x00040000;
694 return true;
695 }
696
697 for (int i = 1; i <= retries; i++) {
698 *bits = reset_bits; // reinit to only track last retry
699
700 // We used to do an "os::yield_all(i)" call here with the intention
701 // that yielding would increase on each retry. However, the parameter
702 // is ignored on Linux which means the yield didn't scale up. Waiting
703 // on the SR_lock below provides a much more predictable scale up for
704 // the delay. It also provides a simple/direct point to check for any
705 // safepoint requests from the VMThread
706
707 {
708 MutexLocker ml(SR_lock());
709 // wait with safepoint check (if we're a JavaThread - the WatcherThread
710 // can also call this) and increase delay with each retry
711 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
712
713 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
714 delay, bits);
715
716 // It is possible for the external suspend request to be cancelled
717 // (by a resume) before the actual suspend operation is completed.
718 // Refresh our local copy to see if we still need to wait.
719 pending = is_external_suspend();
720 }
721
722 if (!pending) {
723 // A cancelled suspend request is the only false return from
724 // is_ext_suspend_completed() that keeps us from staying in the
725 // retry loop.
726 *bits |= 0x00080000;
727 return false;
728 }
729
730 if (is_suspended) {
731 *bits |= 0x00100000;
732 return true;
733 }
734 } // end retry loop
735
736 // thread did not suspend after all our retries
737 *bits |= 0x00200000;
738 return false;
739 }
740
741 #ifndef PRODUCT
742 void JavaThread::record_jump(address target, address instr, const char* file,
743 int line) {
744
745 // This should not need to be atomic as the only way for simultaneous
746 // updates is via interrupts. Even then this should be rare or non-existent
747 // and we don't care that much anyway.
748
749 int index = _jmp_ring_index;
750 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
751 _jmp_ring[index]._target = (intptr_t) target;
752 _jmp_ring[index]._instruction = (intptr_t) instr;
753 _jmp_ring[index]._file = file;
754 _jmp_ring[index]._line = line;
755 }
756 #endif // PRODUCT
757
758 // Called by flat profiler
759 // Callers have already called wait_for_ext_suspend_completion
760 // The assertion for that is currently too complex to put here:
761 bool JavaThread::profile_last_Java_frame(frame* _fr) {
762 bool gotframe = false;
763 // self suspension saves needed state.
764 if (has_last_Java_frame() && _anchor.walkable()) {
765 *_fr = pd_last_frame();
766 gotframe = true;
767 }
768 return gotframe;
769 }
770
771 void Thread::interrupt(Thread* thread) {
772 trace("interrupt", thread);
773 debug_only(check_for_dangling_thread_pointer(thread);)
774 os::interrupt(thread);
775 }
776
777 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
778 trace("is_interrupted", thread);
779 debug_only(check_for_dangling_thread_pointer(thread);)
780 // Note: If clear_interrupted==false, this simply fetches and
781 // returns the value of the field osthread()->interrupted().
782 return os::is_interrupted(thread, clear_interrupted);
783 }
784
785
786 // GC Support
787 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
788 jint thread_parity = _oops_do_parity;
789 if (thread_parity != strong_roots_parity) {
790 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
791 if (res == thread_parity) {
792 return true;
793 } else {
794 guarantee(res == strong_roots_parity, "Or else what?");
795 assert(SharedHeap::heap()->workers()->active_workers() > 0,
796 "Should only fail when parallel.");
797 return false;
798 }
799 }
800 assert(SharedHeap::heap()->workers()->active_workers() > 0,
801 "Should only fail when parallel.");
802 return false;
803 }
804
805 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
806 active_handles()->oops_do(f);
807 // Do oop for ThreadShadow
808 f->do_oop((oop*)&_pending_exception);
809 handle_area()->oops_do(f);
810 }
811
812 void Thread::nmethods_do(CodeBlobClosure* cf) {
813 // no nmethods in a generic thread...
814 }
815
816 void Thread::metadata_do(void f(Metadata*)) {
817 if (metadata_handles() != NULL) {
818 for (int i = 0; i< metadata_handles()->length(); i++) {
819 f(metadata_handles()->at(i));
820 }
821 }
822 }
823
824 void Thread::print_on(outputStream* st) const {
825 // get_priority assumes osthread initialized
826 if (osthread() != NULL) {
827 int os_prio;
828 if (os::get_native_priority(this, &os_prio) == OS_OK) {
829 st->print("os_prio=%d ", os_prio);
830 }
831 st->print("tid=" INTPTR_FORMAT " ", this);
832 ext().print_on(st);
833 osthread()->print_on(st);
834 }
835 debug_only(if (WizardMode) print_owned_locks_on(st);)
836 }
837
838 // Thread::print_on_error() is called by fatal error handler. Don't use
839 // any lock or allocate memory.
840 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
841 if (is_VM_thread()) st->print("VMThread");
842 else if (is_Compiler_thread()) st->print("CompilerThread");
843 else if (is_Java_thread()) st->print("JavaThread");
844 else if (is_GC_task_thread()) st->print("GCTaskThread");
845 else if (is_Watcher_thread()) st->print("WatcherThread");
846 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
847 else st->print("Thread");
848
849 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
850 _stack_base - _stack_size, _stack_base);
851
852 if (osthread()) {
853 st->print(" [id=%d]", osthread()->thread_id());
854 }
855 }
856
857 #ifdef ASSERT
858 void Thread::print_owned_locks_on(outputStream* st) const {
859 Monitor *cur = _owned_locks;
860 if (cur == NULL) {
861 st->print(" (no locks) ");
862 } else {
863 st->print_cr(" Locks owned:");
864 while (cur) {
865 cur->print_on(st);
866 cur = cur->next();
867 }
868 }
869 }
870
871 static int ref_use_count = 0;
872
873 bool Thread::owns_locks_but_compiled_lock() const {
874 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
875 if (cur != Compile_lock) return true;
876 }
877 return false;
878 }
879
880
881 #endif
882
883 #ifndef PRODUCT
884
885 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
886 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
887 // no threads which allow_vm_block's are held
888 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
889 // Check if current thread is allowed to block at a safepoint
890 if (!(_allow_safepoint_count == 0)) {
891 fatal("Possible safepoint reached by thread that does not allow it");
892 }
893 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
894 fatal("LEAF method calling lock?");
895 }
896
897 #ifdef ASSERT
898 if (potential_vm_operation && is_Java_thread()
899 && !Universe::is_bootstrapping()) {
900 // Make sure we do not hold any locks that the VM thread also uses.
901 // This could potentially lead to deadlocks
902 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
903 // Threads_lock is special, since the safepoint synchronization will not start before this is
904 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
905 // since it is used to transfer control between JavaThreads and the VMThread
906 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
907 if ((cur->allow_vm_block() &&
908 cur != Threads_lock &&
909 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
910 cur != VMOperationRequest_lock &&
911 cur != VMOperationQueue_lock) ||
912 cur->rank() == Mutex::special) {
913 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
914 }
915 }
916 }
917
918 if (GCALotAtAllSafepoints) {
919 // We could enter a safepoint here and thus have a gc
920 InterfaceSupport::check_gc_alot();
921 }
922 #endif
923 }
924 #endif
925
926 bool Thread::is_in_stack(address adr) const {
927 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
928 address end = os::current_stack_pointer();
929 // Allow non Java threads to call this without stack_base
930 if (_stack_base == NULL) return true;
931 if (stack_base() >= adr && adr >= end) return true;
932
933 return false;
934 }
935
936
937 bool Thread::is_in_usable_stack(address adr) const {
938 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
939 size_t usable_stack_size = _stack_size - stack_guard_size;
940
941 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
942 }
943
944
945 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
946 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
947 // used for compilation in the future. If that change is made, the need for these methods
948 // should be revisited, and they should be removed if possible.
949
950 bool Thread::is_lock_owned(address adr) const {
951 return on_local_stack(adr);
952 }
953
954 bool Thread::set_as_starting_thread() {
955 // NOTE: this must be called inside the main thread.
956 return os::create_main_thread((JavaThread*)this);
957 }
958
959 static void initialize_class(Symbol* class_name, TRAPS) {
960 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
961 InstanceKlass::cast(klass)->initialize(CHECK);
962 }
963
964
965 // Creates the initial ThreadGroup
966 static Handle create_initial_thread_group(TRAPS) {
967 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
968 instanceKlassHandle klass (THREAD, k);
969
970 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
971 {
972 JavaValue result(T_VOID);
973 JavaCalls::call_special(&result,
974 system_instance,
975 klass,
976 vmSymbols::object_initializer_name(),
977 vmSymbols::void_method_signature(),
978 CHECK_NH);
979 }
980 Universe::set_system_thread_group(system_instance());
981
982 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
983 {
984 JavaValue result(T_VOID);
985 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
986 JavaCalls::call_special(&result,
987 main_instance,
988 klass,
989 vmSymbols::object_initializer_name(),
990 vmSymbols::threadgroup_string_void_signature(),
991 system_instance,
992 string,
993 CHECK_NH);
994 }
995 return main_instance;
996 }
997
998 // Creates the initial Thread
999 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
1000 TRAPS) {
1001 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1002 instanceKlassHandle klass (THREAD, k);
1003 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1004
1005 java_lang_Thread::set_thread(thread_oop(), thread);
1006 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1007 thread->set_threadObj(thread_oop());
1008
1009 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1010
1011 JavaValue result(T_VOID);
1012 JavaCalls::call_special(&result, thread_oop,
1013 klass,
1014 vmSymbols::object_initializer_name(),
1015 vmSymbols::threadgroup_string_void_signature(),
1016 thread_group,
1017 string,
1018 CHECK_NULL);
1019 return thread_oop();
1020 }
1021
1022 static void call_initializeSystemClass(TRAPS) {
1023 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1024 instanceKlassHandle klass (THREAD, k);
1025
1026 JavaValue result(T_VOID);
1027 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1028 vmSymbols::void_method_signature(), CHECK);
1029 }
1030
1031 char java_runtime_name[128] = "";
1032 char java_runtime_version[128] = "";
1033
1034 // extract the JRE name from sun.misc.Version.java_runtime_name
1035 static const char* get_java_runtime_name(TRAPS) {
1036 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1037 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1038 fieldDescriptor fd;
1039 bool found = k != NULL &&
1040 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1041 vmSymbols::string_signature(), &fd);
1042 if (found) {
1043 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1044 if (name_oop == NULL) {
1045 return NULL;
1046 }
1047 const char* name = java_lang_String::as_utf8_string(name_oop,
1048 java_runtime_name,
1049 sizeof(java_runtime_name));
1050 return name;
1051 } else {
1052 return NULL;
1053 }
1054 }
1055
1056 // extract the JRE version from sun.misc.Version.java_runtime_version
1057 static const char* get_java_runtime_version(TRAPS) {
1058 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1059 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1060 fieldDescriptor fd;
1061 bool found = k != NULL &&
1062 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1063 vmSymbols::string_signature(), &fd);
1064 if (found) {
1065 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1066 if (name_oop == NULL) {
1067 return NULL;
1068 }
1069 const char* name = java_lang_String::as_utf8_string(name_oop,
1070 java_runtime_version,
1071 sizeof(java_runtime_version));
1072 return name;
1073 } else {
1074 return NULL;
1075 }
1076 }
1077
1078 // General purpose hook into Java code, run once when the VM is initialized.
1079 // The Java library method itself may be changed independently from the VM.
1080 static void call_postVMInitHook(TRAPS) {
1081 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1082 instanceKlassHandle klass (THREAD, k);
1083 if (klass.not_null()) {
1084 JavaValue result(T_VOID);
1085 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1086 vmSymbols::void_method_signature(),
1087 CHECK);
1088 }
1089 }
1090
1091 static void reset_vm_info_property(TRAPS) {
1092 // the vm info string
1093 ResourceMark rm(THREAD);
1094 const char *vm_info = VM_Version::vm_info_string();
1095
1096 // java.lang.System class
1097 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1098 instanceKlassHandle klass (THREAD, k);
1099
1100 // setProperty arguments
1101 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1102 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1103
1104 // return value
1105 JavaValue r(T_OBJECT);
1106
1107 // public static String setProperty(String key, String value);
1108 JavaCalls::call_static(&r,
1109 klass,
1110 vmSymbols::setProperty_name(),
1111 vmSymbols::string_string_string_signature(),
1112 key_str,
1113 value_str,
1114 CHECK);
1115 }
1116
1117
1118 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name,
1119 bool daemon, TRAPS) {
1120 assert(thread_group.not_null(), "thread group should be specified");
1121 assert(threadObj() == NULL, "should only create Java thread object once");
1122
1123 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1124 instanceKlassHandle klass (THREAD, k);
1125 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1126
1127 java_lang_Thread::set_thread(thread_oop(), this);
1128 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1129 set_threadObj(thread_oop());
1130
1131 JavaValue result(T_VOID);
1132 if (thread_name != NULL) {
1133 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1134 // Thread gets assigned specified name and null target
1135 JavaCalls::call_special(&result,
1136 thread_oop,
1137 klass,
1138 vmSymbols::object_initializer_name(),
1139 vmSymbols::threadgroup_string_void_signature(),
1140 thread_group, // Argument 1
1141 name, // Argument 2
1142 THREAD);
1143 } else {
1144 // Thread gets assigned name "Thread-nnn" and null target
1145 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1146 JavaCalls::call_special(&result,
1147 thread_oop,
1148 klass,
1149 vmSymbols::object_initializer_name(),
1150 vmSymbols::threadgroup_runnable_void_signature(),
1151 thread_group, // Argument 1
1152 Handle(), // Argument 2
1153 THREAD);
1154 }
1155
1156
1157 if (daemon) {
1158 java_lang_Thread::set_daemon(thread_oop());
1159 }
1160
1161 if (HAS_PENDING_EXCEPTION) {
1162 return;
1163 }
1164
1165 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1166 Handle threadObj(this, this->threadObj());
1167
1168 JavaCalls::call_special(&result,
1169 thread_group,
1170 group,
1171 vmSymbols::add_method_name(),
1172 vmSymbols::thread_void_signature(),
1173 threadObj, // Arg 1
1174 THREAD);
1175
1176
1177 }
1178
1179 // NamedThread -- non-JavaThread subclasses with multiple
1180 // uniquely named instances should derive from this.
1181 NamedThread::NamedThread() : Thread() {
1182 _name = NULL;
1183 _processed_thread = NULL;
1184 }
1185
1186 NamedThread::~NamedThread() {
1187 if (_name != NULL) {
1188 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1189 _name = NULL;
1190 }
1191 }
1192
1193 void NamedThread::set_name(const char* format, ...) {
1194 guarantee(_name == NULL, "Only get to set name once.");
1195 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1196 guarantee(_name != NULL, "alloc failure");
1197 va_list ap;
1198 va_start(ap, format);
1199 jio_vsnprintf(_name, max_name_len, format, ap);
1200 va_end(ap);
1201 }
1202
1203 void NamedThread::print_on(outputStream* st) const {
1204 st->print("\"%s\" ", name());
1205 Thread::print_on(st);
1206 st->cr();
1207 }
1208
1209
1210 // ======= WatcherThread ========
1211
1212 // The watcher thread exists to simulate timer interrupts. It should
1213 // be replaced by an abstraction over whatever native support for
1214 // timer interrupts exists on the platform.
1215
1216 WatcherThread* WatcherThread::_watcher_thread = NULL;
1217 bool WatcherThread::_startable = false;
1218 volatile bool WatcherThread::_should_terminate = false;
1219
1220 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1221 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1222 if (os::create_thread(this, os::watcher_thread)) {
1223 _watcher_thread = this;
1224
1225 // Set the watcher thread to the highest OS priority which should not be
1226 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1227 // is created. The only normal thread using this priority is the reference
1228 // handler thread, which runs for very short intervals only.
1229 // If the VMThread's priority is not lower than the WatcherThread profiling
1230 // will be inaccurate.
1231 os::set_priority(this, MaxPriority);
1232 if (!DisableStartThread) {
1233 os::start_thread(this);
1234 }
1235 }
1236 }
1237
1238 int WatcherThread::sleep() const {
1239 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1240
1241 // remaining will be zero if there are no tasks,
1242 // causing the WatcherThread to sleep until a task is
1243 // enrolled
1244 int remaining = PeriodicTask::time_to_wait();
1245 int time_slept = 0;
1246
1247 // we expect this to timeout - we only ever get unparked when
1248 // we should terminate or when a new task has been enrolled
1249 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1250
1251 jlong time_before_loop = os::javaTimeNanos();
1252
1253 for (;;) {
1254 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1255 jlong now = os::javaTimeNanos();
1256
1257 if (remaining == 0) {
1258 // if we didn't have any tasks we could have waited for a long time
1259 // consider the time_slept zero and reset time_before_loop
1260 time_slept = 0;
1261 time_before_loop = now;
1262 } else {
1263 // need to recalculate since we might have new tasks in _tasks
1264 time_slept = (int) ((now - time_before_loop) / 1000000);
1265 }
1266
1267 // Change to task list or spurious wakeup of some kind
1268 if (timedout || _should_terminate) {
1269 break;
1270 }
1271
1272 remaining = PeriodicTask::time_to_wait();
1273 if (remaining == 0) {
1274 // Last task was just disenrolled so loop around and wait until
1275 // another task gets enrolled
1276 continue;
1277 }
1278
1279 remaining -= time_slept;
1280 if (remaining <= 0) {
1281 break;
1282 }
1283 }
1284
1285 return time_slept;
1286 }
1287
1288 void WatcherThread::run() {
1289 assert(this == watcher_thread(), "just checking");
1290
1291 this->record_stack_base_and_size();
1292 this->initialize_thread_local_storage();
1293 this->set_native_thread_name(this->name());
1294 this->set_active_handles(JNIHandleBlock::allocate_block());
1295 while (!_should_terminate) {
1296 assert(watcher_thread() == Thread::current(), "thread consistency check");
1297 assert(watcher_thread() == this, "thread consistency check");
1298
1299 // Calculate how long it'll be until the next PeriodicTask work
1300 // should be done, and sleep that amount of time.
1301 int time_waited = sleep();
1302
1303 if (is_error_reported()) {
1304 // A fatal error has happened, the error handler(VMError::report_and_die)
1305 // should abort JVM after creating an error log file. However in some
1306 // rare cases, the error handler itself might deadlock. Here we try to
1307 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1308 //
1309 // This code is in WatcherThread because WatcherThread wakes up
1310 // periodically so the fatal error handler doesn't need to do anything;
1311 // also because the WatcherThread is less likely to crash than other
1312 // threads.
1313
1314 for (;;) {
1315 if (!ShowMessageBoxOnError
1316 && (OnError == NULL || OnError[0] == '\0')
1317 && Arguments::abort_hook() == NULL) {
1318 os::sleep(this, 2 * 60 * 1000, false);
1319 fdStream err(defaultStream::output_fd());
1320 err.print_raw_cr("# [ timer expired, abort... ]");
1321 // skip atexit/vm_exit/vm_abort hooks
1322 os::die();
1323 }
1324
1325 // Wake up 5 seconds later, the fatal handler may reset OnError or
1326 // ShowMessageBoxOnError when it is ready to abort.
1327 os::sleep(this, 5 * 1000, false);
1328 }
1329 }
1330
1331 PeriodicTask::real_time_tick(time_waited);
1332 }
1333
1334 // Signal that it is terminated
1335 {
1336 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1337 _watcher_thread = NULL;
1338 Terminator_lock->notify();
1339 }
1340
1341 // Thread destructor usually does this..
1342 ThreadLocalStorage::set_thread(NULL);
1343 }
1344
1345 void WatcherThread::start() {
1346 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1347
1348 if (watcher_thread() == NULL && _startable) {
1349 _should_terminate = false;
1350 // Create the single instance of WatcherThread
1351 new WatcherThread();
1352 }
1353 }
1354
1355 void WatcherThread::make_startable() {
1356 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1357 _startable = true;
1358 }
1359
1360 void WatcherThread::stop() {
1361 // Get the PeriodicTask_lock if we can. If we cannot, then the
1362 // WatcherThread is using it and we don't want to block on that lock
1363 // here because that might cause a safepoint deadlock depending on
1364 // what the current WatcherThread tasks are doing.
1365 bool have_lock = PeriodicTask_lock->try_lock();
1366
1367 _should_terminate = true;
1368 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1369
1370 if (have_lock) {
1371 WatcherThread* watcher = watcher_thread();
1372 if (watcher != NULL) {
1373 // If we managed to get the lock, then we should unpark the
1374 // WatcherThread so that it can see we want it to stop.
1375 watcher->unpark();
1376 }
1377
1378 PeriodicTask_lock->unlock();
1379 }
1380
1381 // it is ok to take late safepoints here, if needed
1382 MutexLocker mu(Terminator_lock);
1383
1384 while (watcher_thread() != NULL) {
1385 // This wait should make safepoint checks, wait without a timeout,
1386 // and wait as a suspend-equivalent condition.
1387 //
1388 // Note: If the FlatProfiler is running, then this thread is waiting
1389 // for the WatcherThread to terminate and the WatcherThread, via the
1390 // FlatProfiler task, is waiting for the external suspend request on
1391 // this thread to complete. wait_for_ext_suspend_completion() will
1392 // eventually timeout, but that takes time. Making this wait a
1393 // suspend-equivalent condition solves that timeout problem.
1394 //
1395 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1396 Mutex::_as_suspend_equivalent_flag);
1397 }
1398 }
1399
1400 void WatcherThread::unpark() {
1401 MutexLockerEx ml(PeriodicTask_lock->owned_by_self()
1402 ? NULL
1403 : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1404 PeriodicTask_lock->notify();
1405 }
1406
1407 void WatcherThread::print_on(outputStream* st) const {
1408 st->print("\"%s\" ", name());
1409 Thread::print_on(st);
1410 st->cr();
1411 }
1412
1413 // ======= JavaThread ========
1414
1415 // A JavaThread is a normal Java thread
1416
1417 void JavaThread::initialize() {
1418 // Initialize fields
1419
1420 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1421 set_claimed_par_id(UINT_MAX);
1422
1423 set_saved_exception_pc(NULL);
1424 set_threadObj(NULL);
1425 _anchor.clear();
1426 set_entry_point(NULL);
1427 set_jni_functions(jni_functions());
1428 set_callee_target(NULL);
1429 set_vm_result(NULL);
1430 set_vm_result_2(NULL);
1431 set_vframe_array_head(NULL);
1432 set_vframe_array_last(NULL);
1433 set_deferred_locals(NULL);
1434 set_deopt_mark(NULL);
1435 set_deopt_nmethod(NULL);
1436 clear_must_deopt_id();
1437 set_monitor_chunks(NULL);
1438 set_next(NULL);
1439 set_thread_state(_thread_new);
1440 _terminated = _not_terminated;
1441 _privileged_stack_top = NULL;
1442 _array_for_gc = NULL;
1443 _suspend_equivalent = false;
1444 _in_deopt_handler = 0;
1445 _doing_unsafe_access = false;
1446 _stack_guard_state = stack_guard_unused;
1447 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1448 _exception_pc = 0;
1449 _exception_handler_pc = 0;
1450 _is_method_handle_return = 0;
1451 _jvmti_thread_state= NULL;
1452 _should_post_on_exceptions_flag = JNI_FALSE;
1453 _jvmti_get_loaded_classes_closure = NULL;
1454 _interp_only_mode = 0;
1455 _special_runtime_exit_condition = _no_async_condition;
1456 _pending_async_exception = NULL;
1457 _thread_stat = NULL;
1458 _thread_stat = new ThreadStatistics();
1459 _blocked_on_compilation = false;
1460 _jni_active_critical = 0;
1461 _pending_jni_exception_check_fn = NULL;
1462 _do_not_unlock_if_synchronized = false;
1463 _cached_monitor_info = NULL;
1464 _parker = Parker::Allocate(this);
1465
1466 #ifndef PRODUCT
1467 _jmp_ring_index = 0;
1468 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1469 record_jump(NULL, NULL, NULL, 0);
1470 }
1471 #endif // PRODUCT
1472
1473 set_thread_profiler(NULL);
1474 if (FlatProfiler::is_active()) {
1475 // This is where we would decide to either give each thread it's own profiler
1476 // or use one global one from FlatProfiler,
1477 // or up to some count of the number of profiled threads, etc.
1478 ThreadProfiler* pp = new ThreadProfiler();
1479 pp->engage();
1480 set_thread_profiler(pp);
1481 }
1482
1483 // Setup safepoint state info for this thread
1484 ThreadSafepointState::create(this);
1485
1486 debug_only(_java_call_counter = 0);
1487
1488 // JVMTI PopFrame support
1489 _popframe_condition = popframe_inactive;
1490 _popframe_preserved_args = NULL;
1491 _popframe_preserved_args_size = 0;
1492
1493 pd_initialize();
1494 }
1495
1496 #if INCLUDE_ALL_GCS
1497 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1498 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1499 #endif // INCLUDE_ALL_GCS
1500
1501 JavaThread::JavaThread(bool is_attaching_via_jni) :
1502 Thread()
1503 #if INCLUDE_ALL_GCS
1504 , _satb_mark_queue(&_satb_mark_queue_set),
1505 _dirty_card_queue(&_dirty_card_queue_set)
1506 #endif // INCLUDE_ALL_GCS
1507 {
1508 initialize();
1509 if (is_attaching_via_jni) {
1510 _jni_attach_state = _attaching_via_jni;
1511 } else {
1512 _jni_attach_state = _not_attaching_via_jni;
1513 }
1514 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1515 }
1516
1517 bool JavaThread::reguard_stack(address cur_sp) {
1518 if (_stack_guard_state != stack_guard_yellow_disabled) {
1519 return true; // Stack already guarded or guard pages not needed.
1520 }
1521
1522 if (register_stack_overflow()) {
1523 // For those architectures which have separate register and
1524 // memory stacks, we must check the register stack to see if
1525 // it has overflowed.
1526 return false;
1527 }
1528
1529 // Java code never executes within the yellow zone: the latter is only
1530 // there to provoke an exception during stack banging. If java code
1531 // is executing there, either StackShadowPages should be larger, or
1532 // some exception code in c1, c2 or the interpreter isn't unwinding
1533 // when it should.
1534 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1535
1536 enable_stack_yellow_zone();
1537 return true;
1538 }
1539
1540 bool JavaThread::reguard_stack(void) {
1541 return reguard_stack(os::current_stack_pointer());
1542 }
1543
1544
1545 void JavaThread::block_if_vm_exited() {
1546 if (_terminated == _vm_exited) {
1547 // _vm_exited is set at safepoint, and Threads_lock is never released
1548 // we will block here forever
1549 Threads_lock->lock_without_safepoint_check();
1550 ShouldNotReachHere();
1551 }
1552 }
1553
1554
1555 // Remove this ifdef when C1 is ported to the compiler interface.
1556 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1557 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1558
1559 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1560 Thread()
1561 #if INCLUDE_ALL_GCS
1562 , _satb_mark_queue(&_satb_mark_queue_set),
1563 _dirty_card_queue(&_dirty_card_queue_set)
1564 #endif // INCLUDE_ALL_GCS
1565 {
1566 if (TraceThreadEvents) {
1567 tty->print_cr("creating thread %p", this);
1568 }
1569 initialize();
1570 _jni_attach_state = _not_attaching_via_jni;
1571 set_entry_point(entry_point);
1572 // Create the native thread itself.
1573 // %note runtime_23
1574 os::ThreadType thr_type = os::java_thread;
1575 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1576 os::java_thread;
1577 os::create_thread(this, thr_type, stack_sz);
1578 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1579 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1580 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1581 // the exception consists of creating the exception object & initializing it, initialization
1582 // will leave the VM via a JavaCall and then all locks must be unlocked).
1583 //
1584 // The thread is still suspended when we reach here. Thread must be explicit started
1585 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1586 // by calling Threads:add. The reason why this is not done here, is because the thread
1587 // object must be fully initialized (take a look at JVM_Start)
1588 }
1589
1590 JavaThread::~JavaThread() {
1591 if (TraceThreadEvents) {
1592 tty->print_cr("terminate thread %p", this);
1593 }
1594
1595 // JSR166 -- return the parker to the free list
1596 Parker::Release(_parker);
1597 _parker = NULL;
1598
1599 // Free any remaining previous UnrollBlock
1600 vframeArray* old_array = vframe_array_last();
1601
1602 if (old_array != NULL) {
1603 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1604 old_array->set_unroll_block(NULL);
1605 delete old_info;
1606 delete old_array;
1607 }
1608
1609 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1610 if (deferred != NULL) {
1611 // This can only happen if thread is destroyed before deoptimization occurs.
1612 assert(deferred->length() != 0, "empty array!");
1613 do {
1614 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1615 deferred->remove_at(0);
1616 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1617 delete dlv;
1618 } while (deferred->length() != 0);
1619 delete deferred;
1620 }
1621
1622 // All Java related clean up happens in exit
1623 ThreadSafepointState::destroy(this);
1624 if (_thread_profiler != NULL) delete _thread_profiler;
1625 if (_thread_stat != NULL) delete _thread_stat;
1626 }
1627
1628
1629 // The first routine called by a new Java thread
1630 void JavaThread::run() {
1631 // initialize thread-local alloc buffer related fields
1632 this->initialize_tlab();
1633
1634 // used to test validity of stack trace backs
1635 this->record_base_of_stack_pointer();
1636
1637 // Record real stack base and size.
1638 this->record_stack_base_and_size();
1639
1640 // Initialize thread local storage; set before calling MutexLocker
1641 this->initialize_thread_local_storage();
1642
1643 this->create_stack_guard_pages();
1644
1645 this->cache_global_variables();
1646
1647 // Thread is now sufficient initialized to be handled by the safepoint code as being
1648 // in the VM. Change thread state from _thread_new to _thread_in_vm
1649 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1650
1651 assert(JavaThread::current() == this, "sanity check");
1652 assert(!Thread::current()->owns_locks(), "sanity check");
1653
1654 DTRACE_THREAD_PROBE(start, this);
1655
1656 // This operation might block. We call that after all safepoint checks for a new thread has
1657 // been completed.
1658 this->set_active_handles(JNIHandleBlock::allocate_block());
1659
1660 if (JvmtiExport::should_post_thread_life()) {
1661 JvmtiExport::post_thread_start(this);
1662 }
1663
1664 EventThreadStart event;
1665 if (event.should_commit()) {
1666 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1667 event.commit();
1668 }
1669
1670 // We call another function to do the rest so we are sure that the stack addresses used
1671 // from there will be lower than the stack base just computed
1672 thread_main_inner();
1673
1674 // Note, thread is no longer valid at this point!
1675 }
1676
1677
1678 void JavaThread::thread_main_inner() {
1679 assert(JavaThread::current() == this, "sanity check");
1680 assert(this->threadObj() != NULL, "just checking");
1681
1682 // Execute thread entry point unless this thread has a pending exception
1683 // or has been stopped before starting.
1684 // Note: Due to JVM_StopThread we can have pending exceptions already!
1685 if (!this->has_pending_exception() &&
1686 !java_lang_Thread::is_stillborn(this->threadObj())) {
1687 {
1688 ResourceMark rm(this);
1689 this->set_native_thread_name(this->get_thread_name());
1690 }
1691 HandleMark hm(this);
1692 this->entry_point()(this, this);
1693 }
1694
1695 DTRACE_THREAD_PROBE(stop, this);
1696
1697 this->exit(false);
1698 delete this;
1699 }
1700
1701
1702 static void ensure_join(JavaThread* thread) {
1703 // We do not need to grap the Threads_lock, since we are operating on ourself.
1704 Handle threadObj(thread, thread->threadObj());
1705 assert(threadObj.not_null(), "java thread object must exist");
1706 ObjectLocker lock(threadObj, thread);
1707 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1708 thread->clear_pending_exception();
1709 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1710 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1711 // Clear the native thread instance - this makes isAlive return false and allows the join()
1712 // to complete once we've done the notify_all below
1713 java_lang_Thread::set_thread(threadObj(), NULL);
1714 lock.notify_all(thread);
1715 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1716 thread->clear_pending_exception();
1717 }
1718
1719
1720 // For any new cleanup additions, please check to see if they need to be applied to
1721 // cleanup_failed_attach_current_thread as well.
1722 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1723 assert(this == JavaThread::current(), "thread consistency check");
1724
1725 HandleMark hm(this);
1726 Handle uncaught_exception(this, this->pending_exception());
1727 this->clear_pending_exception();
1728 Handle threadObj(this, this->threadObj());
1729 assert(threadObj.not_null(), "Java thread object should be created");
1730
1731 if (get_thread_profiler() != NULL) {
1732 get_thread_profiler()->disengage();
1733 ResourceMark rm;
1734 get_thread_profiler()->print(get_thread_name());
1735 }
1736
1737
1738 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1739 {
1740 EXCEPTION_MARK;
1741
1742 CLEAR_PENDING_EXCEPTION;
1743 }
1744 if (!destroy_vm) {
1745 if (uncaught_exception.not_null()) {
1746 EXCEPTION_MARK;
1747 // Call method Thread.dispatchUncaughtException().
1748 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1749 JavaValue result(T_VOID);
1750 JavaCalls::call_virtual(&result,
1751 threadObj, thread_klass,
1752 vmSymbols::dispatchUncaughtException_name(),
1753 vmSymbols::throwable_void_signature(),
1754 uncaught_exception,
1755 THREAD);
1756 if (HAS_PENDING_EXCEPTION) {
1757 ResourceMark rm(this);
1758 jio_fprintf(defaultStream::error_stream(),
1759 "\nException: %s thrown from the UncaughtExceptionHandler"
1760 " in thread \"%s\"\n",
1761 pending_exception()->klass()->external_name(),
1762 get_thread_name());
1763 CLEAR_PENDING_EXCEPTION;
1764 }
1765 }
1766
1767 // Called before the java thread exit since we want to read info
1768 // from java_lang_Thread object
1769 EventThreadEnd event;
1770 if (event.should_commit()) {
1771 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1772 event.commit();
1773 }
1774
1775 // Call after last event on thread
1776 EVENT_THREAD_EXIT(this);
1777
1778 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1779 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1780 // is deprecated anyhow.
1781 if (!is_Compiler_thread()) {
1782 int count = 3;
1783 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1784 EXCEPTION_MARK;
1785 JavaValue result(T_VOID);
1786 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1787 JavaCalls::call_virtual(&result,
1788 threadObj, thread_klass,
1789 vmSymbols::exit_method_name(),
1790 vmSymbols::void_method_signature(),
1791 THREAD);
1792 CLEAR_PENDING_EXCEPTION;
1793 }
1794 }
1795 // notify JVMTI
1796 if (JvmtiExport::should_post_thread_life()) {
1797 JvmtiExport::post_thread_end(this);
1798 }
1799
1800 // We have notified the agents that we are exiting, before we go on,
1801 // we must check for a pending external suspend request and honor it
1802 // in order to not surprise the thread that made the suspend request.
1803 while (true) {
1804 {
1805 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1806 if (!is_external_suspend()) {
1807 set_terminated(_thread_exiting);
1808 ThreadService::current_thread_exiting(this);
1809 break;
1810 }
1811 // Implied else:
1812 // Things get a little tricky here. We have a pending external
1813 // suspend request, but we are holding the SR_lock so we
1814 // can't just self-suspend. So we temporarily drop the lock
1815 // and then self-suspend.
1816 }
1817
1818 ThreadBlockInVM tbivm(this);
1819 java_suspend_self();
1820
1821 // We're done with this suspend request, but we have to loop around
1822 // and check again. Eventually we will get SR_lock without a pending
1823 // external suspend request and will be able to mark ourselves as
1824 // exiting.
1825 }
1826 // no more external suspends are allowed at this point
1827 } else {
1828 // before_exit() has already posted JVMTI THREAD_END events
1829 }
1830
1831 // Notify waiters on thread object. This has to be done after exit() is called
1832 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1833 // group should have the destroyed bit set before waiters are notified).
1834 ensure_join(this);
1835 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1836
1837 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1838 // held by this thread must be released. A detach operation must only
1839 // get here if there are no Java frames on the stack. Therefore, any
1840 // owned monitors at this point MUST be JNI-acquired monitors which are
1841 // pre-inflated and in the monitor cache.
1842 //
1843 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1844 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1845 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1846 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1847 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1848 }
1849
1850 // These things needs to be done while we are still a Java Thread. Make sure that thread
1851 // is in a consistent state, in case GC happens
1852 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1853
1854 if (active_handles() != NULL) {
1855 JNIHandleBlock* block = active_handles();
1856 set_active_handles(NULL);
1857 JNIHandleBlock::release_block(block);
1858 }
1859
1860 if (free_handle_block() != NULL) {
1861 JNIHandleBlock* block = free_handle_block();
1862 set_free_handle_block(NULL);
1863 JNIHandleBlock::release_block(block);
1864 }
1865
1866 // These have to be removed while this is still a valid thread.
1867 remove_stack_guard_pages();
1868
1869 if (UseTLAB) {
1870 tlab().make_parsable(true); // retire TLAB
1871 }
1872
1873 if (JvmtiEnv::environments_might_exist()) {
1874 JvmtiExport::cleanup_thread(this);
1875 }
1876
1877 // We must flush any deferred card marks before removing a thread from
1878 // the list of active threads.
1879 Universe::heap()->flush_deferred_store_barrier(this);
1880 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1881
1882 #if INCLUDE_ALL_GCS
1883 // We must flush the G1-related buffers before removing a thread
1884 // from the list of active threads. We must do this after any deferred
1885 // card marks have been flushed (above) so that any entries that are
1886 // added to the thread's dirty card queue as a result are not lost.
1887 if (UseG1GC) {
1888 flush_barrier_queues();
1889 }
1890 #endif // INCLUDE_ALL_GCS
1891
1892 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1893 Threads::remove(this);
1894 }
1895
1896 #if INCLUDE_ALL_GCS
1897 // Flush G1-related queues.
1898 void JavaThread::flush_barrier_queues() {
1899 satb_mark_queue().flush();
1900 dirty_card_queue().flush();
1901 }
1902
1903 void JavaThread::initialize_queues() {
1904 assert(!SafepointSynchronize::is_at_safepoint(),
1905 "we should not be at a safepoint");
1906
1907 ObjPtrQueue& satb_queue = satb_mark_queue();
1908 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1909 // The SATB queue should have been constructed with its active
1910 // field set to false.
1911 assert(!satb_queue.is_active(), "SATB queue should not be active");
1912 assert(satb_queue.is_empty(), "SATB queue should be empty");
1913 // If we are creating the thread during a marking cycle, we should
1914 // set the active field of the SATB queue to true.
1915 if (satb_queue_set.is_active()) {
1916 satb_queue.set_active(true);
1917 }
1918
1919 DirtyCardQueue& dirty_queue = dirty_card_queue();
1920 // The dirty card queue should have been constructed with its
1921 // active field set to true.
1922 assert(dirty_queue.is_active(), "dirty card queue should be active");
1923 }
1924 #endif // INCLUDE_ALL_GCS
1925
1926 void JavaThread::cleanup_failed_attach_current_thread() {
1927 if (get_thread_profiler() != NULL) {
1928 get_thread_profiler()->disengage();
1929 ResourceMark rm;
1930 get_thread_profiler()->print(get_thread_name());
1931 }
1932
1933 if (active_handles() != NULL) {
1934 JNIHandleBlock* block = active_handles();
1935 set_active_handles(NULL);
1936 JNIHandleBlock::release_block(block);
1937 }
1938
1939 if (free_handle_block() != NULL) {
1940 JNIHandleBlock* block = free_handle_block();
1941 set_free_handle_block(NULL);
1942 JNIHandleBlock::release_block(block);
1943 }
1944
1945 // These have to be removed while this is still a valid thread.
1946 remove_stack_guard_pages();
1947
1948 if (UseTLAB) {
1949 tlab().make_parsable(true); // retire TLAB, if any
1950 }
1951
1952 #if INCLUDE_ALL_GCS
1953 if (UseG1GC) {
1954 flush_barrier_queues();
1955 }
1956 #endif // INCLUDE_ALL_GCS
1957
1958 Threads::remove(this);
1959 delete this;
1960 }
1961
1962
1963
1964
1965 JavaThread* JavaThread::active() {
1966 Thread* thread = ThreadLocalStorage::thread();
1967 assert(thread != NULL, "just checking");
1968 if (thread->is_Java_thread()) {
1969 return (JavaThread*) thread;
1970 } else {
1971 assert(thread->is_VM_thread(), "this must be a vm thread");
1972 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1973 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1974 assert(ret->is_Java_thread(), "must be a Java thread");
1975 return ret;
1976 }
1977 }
1978
1979 bool JavaThread::is_lock_owned(address adr) const {
1980 if (Thread::is_lock_owned(adr)) return true;
1981
1982 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1983 if (chunk->contains(adr)) return true;
1984 }
1985
1986 return false;
1987 }
1988
1989
1990 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1991 chunk->set_next(monitor_chunks());
1992 set_monitor_chunks(chunk);
1993 }
1994
1995 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1996 guarantee(monitor_chunks() != NULL, "must be non empty");
1997 if (monitor_chunks() == chunk) {
1998 set_monitor_chunks(chunk->next());
1999 } else {
2000 MonitorChunk* prev = monitor_chunks();
2001 while (prev->next() != chunk) prev = prev->next();
2002 prev->set_next(chunk->next());
2003 }
2004 }
2005
2006 // JVM support.
2007
2008 // Note: this function shouldn't block if it's called in
2009 // _thread_in_native_trans state (such as from
2010 // check_special_condition_for_native_trans()).
2011 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2012
2013 if (has_last_Java_frame() && has_async_condition()) {
2014 // If we are at a polling page safepoint (not a poll return)
2015 // then we must defer async exception because live registers
2016 // will be clobbered by the exception path. Poll return is
2017 // ok because the call we a returning from already collides
2018 // with exception handling registers and so there is no issue.
2019 // (The exception handling path kills call result registers but
2020 // this is ok since the exception kills the result anyway).
2021
2022 if (is_at_poll_safepoint()) {
2023 // if the code we are returning to has deoptimized we must defer
2024 // the exception otherwise live registers get clobbered on the
2025 // exception path before deoptimization is able to retrieve them.
2026 //
2027 RegisterMap map(this, false);
2028 frame caller_fr = last_frame().sender(&map);
2029 assert(caller_fr.is_compiled_frame(), "what?");
2030 if (caller_fr.is_deoptimized_frame()) {
2031 if (TraceExceptions) {
2032 ResourceMark rm;
2033 tty->print_cr("deferred async exception at compiled safepoint");
2034 }
2035 return;
2036 }
2037 }
2038 }
2039
2040 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2041 if (condition == _no_async_condition) {
2042 // Conditions have changed since has_special_runtime_exit_condition()
2043 // was called:
2044 // - if we were here only because of an external suspend request,
2045 // then that was taken care of above (or cancelled) so we are done
2046 // - if we were here because of another async request, then it has
2047 // been cleared between the has_special_runtime_exit_condition()
2048 // and now so again we are done
2049 return;
2050 }
2051
2052 // Check for pending async. exception
2053 if (_pending_async_exception != NULL) {
2054 // Only overwrite an already pending exception, if it is not a threadDeath.
2055 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2056
2057 // We cannot call Exceptions::_throw(...) here because we cannot block
2058 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2059
2060 if (TraceExceptions) {
2061 ResourceMark rm;
2062 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2063 if (has_last_Java_frame()) {
2064 frame f = last_frame();
2065 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2066 }
2067 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2068 }
2069 _pending_async_exception = NULL;
2070 clear_has_async_exception();
2071 }
2072 }
2073
2074 if (check_unsafe_error &&
2075 condition == _async_unsafe_access_error && !has_pending_exception()) {
2076 condition = _no_async_condition; // done
2077 switch (thread_state()) {
2078 case _thread_in_vm: {
2079 JavaThread* THREAD = this;
2080 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2081 }
2082 case _thread_in_native: {
2083 ThreadInVMfromNative tiv(this);
2084 JavaThread* THREAD = this;
2085 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2086 }
2087 case _thread_in_Java: {
2088 ThreadInVMfromJava tiv(this);
2089 JavaThread* THREAD = this;
2090 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2091 }
2092 default:
2093 ShouldNotReachHere();
2094 }
2095 }
2096
2097 assert(condition == _no_async_condition || has_pending_exception() ||
2098 (!check_unsafe_error && condition == _async_unsafe_access_error),
2099 "must have handled the async condition, if no exception");
2100 }
2101
2102 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2103 //
2104 // Check for pending external suspend. Internal suspend requests do
2105 // not use handle_special_runtime_exit_condition().
2106 // If JNIEnv proxies are allowed, don't self-suspend if the target
2107 // thread is not the current thread. In older versions of jdbx, jdbx
2108 // threads could call into the VM with another thread's JNIEnv so we
2109 // can be here operating on behalf of a suspended thread (4432884).
2110 bool do_self_suspend = is_external_suspend_with_lock();
2111 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2112 //
2113 // Because thread is external suspended the safepoint code will count
2114 // thread as at a safepoint. This can be odd because we can be here
2115 // as _thread_in_Java which would normally transition to _thread_blocked
2116 // at a safepoint. We would like to mark the thread as _thread_blocked
2117 // before calling java_suspend_self like all other callers of it but
2118 // we must then observe proper safepoint protocol. (We can't leave
2119 // _thread_blocked with a safepoint in progress). However we can be
2120 // here as _thread_in_native_trans so we can't use a normal transition
2121 // constructor/destructor pair because they assert on that type of
2122 // transition. We could do something like:
2123 //
2124 // JavaThreadState state = thread_state();
2125 // set_thread_state(_thread_in_vm);
2126 // {
2127 // ThreadBlockInVM tbivm(this);
2128 // java_suspend_self()
2129 // }
2130 // set_thread_state(_thread_in_vm_trans);
2131 // if (safepoint) block;
2132 // set_thread_state(state);
2133 //
2134 // but that is pretty messy. Instead we just go with the way the
2135 // code has worked before and note that this is the only path to
2136 // java_suspend_self that doesn't put the thread in _thread_blocked
2137 // mode.
2138
2139 frame_anchor()->make_walkable(this);
2140 java_suspend_self();
2141
2142 // We might be here for reasons in addition to the self-suspend request
2143 // so check for other async requests.
2144 }
2145
2146 if (check_asyncs) {
2147 check_and_handle_async_exceptions();
2148 }
2149 }
2150
2151 void JavaThread::send_thread_stop(oop java_throwable) {
2152 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2153 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2154 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2155
2156 // Do not throw asynchronous exceptions against the compiler thread
2157 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2158 if (is_Compiler_thread()) return;
2159
2160 {
2161 // Actually throw the Throwable against the target Thread - however
2162 // only if there is no thread death exception installed already.
2163 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2164 // If the topmost frame is a runtime stub, then we are calling into
2165 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2166 // must deoptimize the caller before continuing, as the compiled exception handler table
2167 // may not be valid
2168 if (has_last_Java_frame()) {
2169 frame f = last_frame();
2170 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2171 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2172 RegisterMap reg_map(this, UseBiasedLocking);
2173 frame compiled_frame = f.sender(®_map);
2174 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2175 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2176 }
2177 }
2178 }
2179
2180 // Set async. pending exception in thread.
2181 set_pending_async_exception(java_throwable);
2182
2183 if (TraceExceptions) {
2184 ResourceMark rm;
2185 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2186 }
2187 // for AbortVMOnException flag
2188 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2189 }
2190 }
2191
2192
2193 // Interrupt thread so it will wake up from a potential wait()
2194 Thread::interrupt(this);
2195 }
2196
2197 // External suspension mechanism.
2198 //
2199 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2200 // to any VM_locks and it is at a transition
2201 // Self-suspension will happen on the transition out of the vm.
2202 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2203 //
2204 // Guarantees on return:
2205 // + Target thread will not execute any new bytecode (that's why we need to
2206 // force a safepoint)
2207 // + Target thread will not enter any new monitors
2208 //
2209 void JavaThread::java_suspend() {
2210 { MutexLocker mu(Threads_lock);
2211 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2212 return;
2213 }
2214 }
2215
2216 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2217 if (!is_external_suspend()) {
2218 // a racing resume has cancelled us; bail out now
2219 return;
2220 }
2221
2222 // suspend is done
2223 uint32_t debug_bits = 0;
2224 // Warning: is_ext_suspend_completed() may temporarily drop the
2225 // SR_lock to allow the thread to reach a stable thread state if
2226 // it is currently in a transient thread state.
2227 if (is_ext_suspend_completed(false /* !called_by_wait */,
2228 SuspendRetryDelay, &debug_bits)) {
2229 return;
2230 }
2231 }
2232
2233 VM_ForceSafepoint vm_suspend;
2234 VMThread::execute(&vm_suspend);
2235 }
2236
2237 // Part II of external suspension.
2238 // A JavaThread self suspends when it detects a pending external suspend
2239 // request. This is usually on transitions. It is also done in places
2240 // where continuing to the next transition would surprise the caller,
2241 // e.g., monitor entry.
2242 //
2243 // Returns the number of times that the thread self-suspended.
2244 //
2245 // Note: DO NOT call java_suspend_self() when you just want to block current
2246 // thread. java_suspend_self() is the second stage of cooperative
2247 // suspension for external suspend requests and should only be used
2248 // to complete an external suspend request.
2249 //
2250 int JavaThread::java_suspend_self() {
2251 int ret = 0;
2252
2253 // we are in the process of exiting so don't suspend
2254 if (is_exiting()) {
2255 clear_external_suspend();
2256 return ret;
2257 }
2258
2259 assert(_anchor.walkable() ||
2260 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2261 "must have walkable stack");
2262
2263 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2264
2265 assert(!this->is_ext_suspended(),
2266 "a thread trying to self-suspend should not already be suspended");
2267
2268 if (this->is_suspend_equivalent()) {
2269 // If we are self-suspending as a result of the lifting of a
2270 // suspend equivalent condition, then the suspend_equivalent
2271 // flag is not cleared until we set the ext_suspended flag so
2272 // that wait_for_ext_suspend_completion() returns consistent
2273 // results.
2274 this->clear_suspend_equivalent();
2275 }
2276
2277 // A racing resume may have cancelled us before we grabbed SR_lock
2278 // above. Or another external suspend request could be waiting for us
2279 // by the time we return from SR_lock()->wait(). The thread
2280 // that requested the suspension may already be trying to walk our
2281 // stack and if we return now, we can change the stack out from under
2282 // it. This would be a "bad thing (TM)" and cause the stack walker
2283 // to crash. We stay self-suspended until there are no more pending
2284 // external suspend requests.
2285 while (is_external_suspend()) {
2286 ret++;
2287 this->set_ext_suspended();
2288
2289 // _ext_suspended flag is cleared by java_resume()
2290 while (is_ext_suspended()) {
2291 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2292 }
2293 }
2294
2295 return ret;
2296 }
2297
2298 #ifdef ASSERT
2299 // verify the JavaThread has not yet been published in the Threads::list, and
2300 // hence doesn't need protection from concurrent access at this stage
2301 void JavaThread::verify_not_published() {
2302 if (!Threads_lock->owned_by_self()) {
2303 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2304 assert(!Threads::includes(this),
2305 "java thread shouldn't have been published yet!");
2306 } else {
2307 assert(!Threads::includes(this),
2308 "java thread shouldn't have been published yet!");
2309 }
2310 }
2311 #endif
2312
2313 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2314 // progress or when _suspend_flags is non-zero.
2315 // Current thread needs to self-suspend if there is a suspend request and/or
2316 // block if a safepoint is in progress.
2317 // Async exception ISN'T checked.
2318 // Note only the ThreadInVMfromNative transition can call this function
2319 // directly and when thread state is _thread_in_native_trans
2320 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2321 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2322
2323 JavaThread *curJT = JavaThread::current();
2324 bool do_self_suspend = thread->is_external_suspend();
2325
2326 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2327
2328 // If JNIEnv proxies are allowed, don't self-suspend if the target
2329 // thread is not the current thread. In older versions of jdbx, jdbx
2330 // threads could call into the VM with another thread's JNIEnv so we
2331 // can be here operating on behalf of a suspended thread (4432884).
2332 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2333 JavaThreadState state = thread->thread_state();
2334
2335 // We mark this thread_blocked state as a suspend-equivalent so
2336 // that a caller to is_ext_suspend_completed() won't be confused.
2337 // The suspend-equivalent state is cleared by java_suspend_self().
2338 thread->set_suspend_equivalent();
2339
2340 // If the safepoint code sees the _thread_in_native_trans state, it will
2341 // wait until the thread changes to other thread state. There is no
2342 // guarantee on how soon we can obtain the SR_lock and complete the
2343 // self-suspend request. It would be a bad idea to let safepoint wait for
2344 // too long. Temporarily change the state to _thread_blocked to
2345 // let the VM thread know that this thread is ready for GC. The problem
2346 // of changing thread state is that safepoint could happen just after
2347 // java_suspend_self() returns after being resumed, and VM thread will
2348 // see the _thread_blocked state. We must check for safepoint
2349 // after restoring the state and make sure we won't leave while a safepoint
2350 // is in progress.
2351 thread->set_thread_state(_thread_blocked);
2352 thread->java_suspend_self();
2353 thread->set_thread_state(state);
2354 // Make sure new state is seen by VM thread
2355 if (os::is_MP()) {
2356 if (UseMembar) {
2357 // Force a fence between the write above and read below
2358 OrderAccess::fence();
2359 } else {
2360 // Must use this rather than serialization page in particular on Windows
2361 InterfaceSupport::serialize_memory(thread);
2362 }
2363 }
2364 }
2365
2366 if (SafepointSynchronize::do_call_back()) {
2367 // If we are safepointing, then block the caller which may not be
2368 // the same as the target thread (see above).
2369 SafepointSynchronize::block(curJT);
2370 }
2371
2372 if (thread->is_deopt_suspend()) {
2373 thread->clear_deopt_suspend();
2374 RegisterMap map(thread, false);
2375 frame f = thread->last_frame();
2376 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2377 f = f.sender(&map);
2378 }
2379 if (f.id() == thread->must_deopt_id()) {
2380 thread->clear_must_deopt_id();
2381 f.deoptimize(thread);
2382 } else {
2383 fatal("missed deoptimization!");
2384 }
2385 }
2386 }
2387
2388 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2389 // progress or when _suspend_flags is non-zero.
2390 // Current thread needs to self-suspend if there is a suspend request and/or
2391 // block if a safepoint is in progress.
2392 // Also check for pending async exception (not including unsafe access error).
2393 // Note only the native==>VM/Java barriers can call this function and when
2394 // thread state is _thread_in_native_trans.
2395 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2396 check_safepoint_and_suspend_for_native_trans(thread);
2397
2398 if (thread->has_async_exception()) {
2399 // We are in _thread_in_native_trans state, don't handle unsafe
2400 // access error since that may block.
2401 thread->check_and_handle_async_exceptions(false);
2402 }
2403 }
2404
2405 // This is a variant of the normal
2406 // check_special_condition_for_native_trans with slightly different
2407 // semantics for use by critical native wrappers. It does all the
2408 // normal checks but also performs the transition back into
2409 // thread_in_Java state. This is required so that critical natives
2410 // can potentially block and perform a GC if they are the last thread
2411 // exiting the GC_locker.
2412 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2413 check_special_condition_for_native_trans(thread);
2414
2415 // Finish the transition
2416 thread->set_thread_state(_thread_in_Java);
2417
2418 if (thread->do_critical_native_unlock()) {
2419 ThreadInVMfromJavaNoAsyncException tiv(thread);
2420 GC_locker::unlock_critical(thread);
2421 thread->clear_critical_native_unlock();
2422 }
2423 }
2424
2425 // We need to guarantee the Threads_lock here, since resumes are not
2426 // allowed during safepoint synchronization
2427 // Can only resume from an external suspension
2428 void JavaThread::java_resume() {
2429 assert_locked_or_safepoint(Threads_lock);
2430
2431 // Sanity check: thread is gone, has started exiting or the thread
2432 // was not externally suspended.
2433 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2434 return;
2435 }
2436
2437 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2438
2439 clear_external_suspend();
2440
2441 if (is_ext_suspended()) {
2442 clear_ext_suspended();
2443 SR_lock()->notify_all();
2444 }
2445 }
2446
2447 void JavaThread::create_stack_guard_pages() {
2448 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2449 address low_addr = stack_base() - stack_size();
2450 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2451
2452 int allocate = os::allocate_stack_guard_pages();
2453 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2454
2455 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2456 warning("Attempt to allocate stack guard pages failed.");
2457 return;
2458 }
2459
2460 if (os::guard_memory((char *) low_addr, len)) {
2461 _stack_guard_state = stack_guard_enabled;
2462 } else {
2463 warning("Attempt to protect stack guard pages failed.");
2464 if (os::uncommit_memory((char *) low_addr, len)) {
2465 warning("Attempt to deallocate stack guard pages failed.");
2466 }
2467 }
2468 }
2469
2470 void JavaThread::remove_stack_guard_pages() {
2471 assert(Thread::current() == this, "from different thread");
2472 if (_stack_guard_state == stack_guard_unused) return;
2473 address low_addr = stack_base() - stack_size();
2474 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2475
2476 if (os::allocate_stack_guard_pages()) {
2477 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2478 _stack_guard_state = stack_guard_unused;
2479 } else {
2480 warning("Attempt to deallocate stack guard pages failed.");
2481 }
2482 } else {
2483 if (_stack_guard_state == stack_guard_unused) return;
2484 if (os::unguard_memory((char *) low_addr, len)) {
2485 _stack_guard_state = stack_guard_unused;
2486 } else {
2487 warning("Attempt to unprotect stack guard pages failed.");
2488 }
2489 }
2490 }
2491
2492 void JavaThread::enable_stack_yellow_zone() {
2493 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2494 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2495
2496 // The base notation is from the stacks point of view, growing downward.
2497 // We need to adjust it to work correctly with guard_memory()
2498 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2499
2500 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2501 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2502
2503 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2504 _stack_guard_state = stack_guard_enabled;
2505 } else {
2506 warning("Attempt to guard stack yellow zone failed.");
2507 }
2508 enable_register_stack_guard();
2509 }
2510
2511 void JavaThread::disable_stack_yellow_zone() {
2512 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2513 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2514
2515 // Simply return if called for a thread that does not use guard pages.
2516 if (_stack_guard_state == stack_guard_unused) return;
2517
2518 // The base notation is from the stacks point of view, growing downward.
2519 // We need to adjust it to work correctly with guard_memory()
2520 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2521
2522 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2523 _stack_guard_state = stack_guard_yellow_disabled;
2524 } else {
2525 warning("Attempt to unguard stack yellow zone failed.");
2526 }
2527 disable_register_stack_guard();
2528 }
2529
2530 void JavaThread::enable_stack_red_zone() {
2531 // The base notation is from the stacks point of view, growing downward.
2532 // We need to adjust it to work correctly with guard_memory()
2533 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2534 address base = stack_red_zone_base() - stack_red_zone_size();
2535
2536 guarantee(base < stack_base(), "Error calculating stack red zone");
2537 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2538
2539 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2540 warning("Attempt to guard stack red zone failed.");
2541 }
2542 }
2543
2544 void JavaThread::disable_stack_red_zone() {
2545 // The base notation is from the stacks point of view, growing downward.
2546 // We need to adjust it to work correctly with guard_memory()
2547 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2548 address base = stack_red_zone_base() - stack_red_zone_size();
2549 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2550 warning("Attempt to unguard stack red zone failed.");
2551 }
2552 }
2553
2554 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2555 // ignore is there is no stack
2556 if (!has_last_Java_frame()) return;
2557 // traverse the stack frames. Starts from top frame.
2558 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2559 frame* fr = fst.current();
2560 f(fr, fst.register_map());
2561 }
2562 }
2563
2564
2565 #ifndef PRODUCT
2566 // Deoptimization
2567 // Function for testing deoptimization
2568 void JavaThread::deoptimize() {
2569 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2570 StackFrameStream fst(this, UseBiasedLocking);
2571 bool deopt = false; // Dump stack only if a deopt actually happens.
2572 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2573 // Iterate over all frames in the thread and deoptimize
2574 for (; !fst.is_done(); fst.next()) {
2575 if (fst.current()->can_be_deoptimized()) {
2576
2577 if (only_at) {
2578 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2579 // consists of comma or carriage return separated numbers so
2580 // search for the current bci in that string.
2581 address pc = fst.current()->pc();
2582 nmethod* nm = (nmethod*) fst.current()->cb();
2583 ScopeDesc* sd = nm->scope_desc_at(pc);
2584 char buffer[8];
2585 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2586 size_t len = strlen(buffer);
2587 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2588 while (found != NULL) {
2589 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2590 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2591 // Check that the bci found is bracketed by terminators.
2592 break;
2593 }
2594 found = strstr(found + 1, buffer);
2595 }
2596 if (!found) {
2597 continue;
2598 }
2599 }
2600
2601 if (DebugDeoptimization && !deopt) {
2602 deopt = true; // One-time only print before deopt
2603 tty->print_cr("[BEFORE Deoptimization]");
2604 trace_frames();
2605 trace_stack();
2606 }
2607 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2608 }
2609 }
2610
2611 if (DebugDeoptimization && deopt) {
2612 tty->print_cr("[AFTER Deoptimization]");
2613 trace_frames();
2614 }
2615 }
2616
2617
2618 // Make zombies
2619 void JavaThread::make_zombies() {
2620 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2621 if (fst.current()->can_be_deoptimized()) {
2622 // it is a Java nmethod
2623 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2624 nm->make_not_entrant();
2625 }
2626 }
2627 }
2628 #endif // PRODUCT
2629
2630
2631 void JavaThread::deoptimized_wrt_marked_nmethods() {
2632 if (!has_last_Java_frame()) return;
2633 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2634 StackFrameStream fst(this, UseBiasedLocking);
2635 for (; !fst.is_done(); fst.next()) {
2636 if (fst.current()->should_be_deoptimized()) {
2637 if (LogCompilation && xtty != NULL) {
2638 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2639 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2640 this->name(), nm != NULL ? nm->compile_id() : -1);
2641 }
2642
2643 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2644 }
2645 }
2646 }
2647
2648
2649 // If the caller is a NamedThread, then remember, in the current scope,
2650 // the given JavaThread in its _processed_thread field.
2651 class RememberProcessedThread: public StackObj {
2652 NamedThread* _cur_thr;
2653 public:
2654 RememberProcessedThread(JavaThread* jthr) {
2655 Thread* thread = Thread::current();
2656 if (thread->is_Named_thread()) {
2657 _cur_thr = (NamedThread *)thread;
2658 _cur_thr->set_processed_thread(jthr);
2659 } else {
2660 _cur_thr = NULL;
2661 }
2662 }
2663
2664 ~RememberProcessedThread() {
2665 if (_cur_thr) {
2666 _cur_thr->set_processed_thread(NULL);
2667 }
2668 }
2669 };
2670
2671 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2672 // Verify that the deferred card marks have been flushed.
2673 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2674
2675 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2676 // since there may be more than one thread using each ThreadProfiler.
2677
2678 // Traverse the GCHandles
2679 Thread::oops_do(f, cld_f, cf);
2680
2681 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2682 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2683
2684 if (has_last_Java_frame()) {
2685 // Record JavaThread to GC thread
2686 RememberProcessedThread rpt(this);
2687
2688 // Traverse the privileged stack
2689 if (_privileged_stack_top != NULL) {
2690 _privileged_stack_top->oops_do(f);
2691 }
2692
2693 // traverse the registered growable array
2694 if (_array_for_gc != NULL) {
2695 for (int index = 0; index < _array_for_gc->length(); index++) {
2696 f->do_oop(_array_for_gc->adr_at(index));
2697 }
2698 }
2699
2700 // Traverse the monitor chunks
2701 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2702 chunk->oops_do(f);
2703 }
2704
2705 // Traverse the execution stack
2706 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2707 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2708 }
2709 }
2710
2711 // callee_target is never live across a gc point so NULL it here should
2712 // it still contain a methdOop.
2713
2714 set_callee_target(NULL);
2715
2716 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2717 // If we have deferred set_locals there might be oops waiting to be
2718 // written
2719 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2720 if (list != NULL) {
2721 for (int i = 0; i < list->length(); i++) {
2722 list->at(i)->oops_do(f);
2723 }
2724 }
2725
2726 // Traverse instance variables at the end since the GC may be moving things
2727 // around using this function
2728 f->do_oop((oop*) &_threadObj);
2729 f->do_oop((oop*) &_vm_result);
2730 f->do_oop((oop*) &_exception_oop);
2731 f->do_oop((oop*) &_pending_async_exception);
2732
2733 if (jvmti_thread_state() != NULL) {
2734 jvmti_thread_state()->oops_do(f);
2735 }
2736 }
2737
2738 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2739 Thread::nmethods_do(cf); // (super method is a no-op)
2740
2741 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2742 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2743
2744 if (has_last_Java_frame()) {
2745 // Traverse the execution stack
2746 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2747 fst.current()->nmethods_do(cf);
2748 }
2749 }
2750 }
2751
2752 void JavaThread::metadata_do(void f(Metadata*)) {
2753 Thread::metadata_do(f);
2754 if (has_last_Java_frame()) {
2755 // Traverse the execution stack to call f() on the methods in the stack
2756 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2757 fst.current()->metadata_do(f);
2758 }
2759 } else if (is_Compiler_thread()) {
2760 // need to walk ciMetadata in current compile tasks to keep alive.
2761 CompilerThread* ct = (CompilerThread*)this;
2762 if (ct->env() != NULL) {
2763 ct->env()->metadata_do(f);
2764 }
2765 }
2766 }
2767
2768 // Printing
2769 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2770 switch (_thread_state) {
2771 case _thread_uninitialized: return "_thread_uninitialized";
2772 case _thread_new: return "_thread_new";
2773 case _thread_new_trans: return "_thread_new_trans";
2774 case _thread_in_native: return "_thread_in_native";
2775 case _thread_in_native_trans: return "_thread_in_native_trans";
2776 case _thread_in_vm: return "_thread_in_vm";
2777 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2778 case _thread_in_Java: return "_thread_in_Java";
2779 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2780 case _thread_blocked: return "_thread_blocked";
2781 case _thread_blocked_trans: return "_thread_blocked_trans";
2782 default: return "unknown thread state";
2783 }
2784 }
2785
2786 #ifndef PRODUCT
2787 void JavaThread::print_thread_state_on(outputStream *st) const {
2788 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2789 };
2790 void JavaThread::print_thread_state() const {
2791 print_thread_state_on(tty);
2792 }
2793 #endif // PRODUCT
2794
2795 // Called by Threads::print() for VM_PrintThreads operation
2796 void JavaThread::print_on(outputStream *st) const {
2797 st->print("\"%s\" ", get_thread_name());
2798 oop thread_oop = threadObj();
2799 if (thread_oop != NULL) {
2800 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2801 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2802 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2803 }
2804 Thread::print_on(st);
2805 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2806 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2807 if (thread_oop != NULL) {
2808 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2809 }
2810 #ifndef PRODUCT
2811 print_thread_state_on(st);
2812 _safepoint_state->print_on(st);
2813 #endif // PRODUCT
2814 }
2815
2816 // Called by fatal error handler. The difference between this and
2817 // JavaThread::print() is that we can't grab lock or allocate memory.
2818 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2819 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2820 oop thread_obj = threadObj();
2821 if (thread_obj != NULL) {
2822 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2823 }
2824 st->print(" [");
2825 st->print("%s", _get_thread_state_name(_thread_state));
2826 if (osthread()) {
2827 st->print(", id=%d", osthread()->thread_id());
2828 }
2829 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2830 _stack_base - _stack_size, _stack_base);
2831 st->print("]");
2832 return;
2833 }
2834
2835 // Verification
2836
2837 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2838
2839 void JavaThread::verify() {
2840 // Verify oops in the thread.
2841 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2842
2843 // Verify the stack frames.
2844 frames_do(frame_verify);
2845 }
2846
2847 // CR 6300358 (sub-CR 2137150)
2848 // Most callers of this method assume that it can't return NULL but a
2849 // thread may not have a name whilst it is in the process of attaching to
2850 // the VM - see CR 6412693, and there are places where a JavaThread can be
2851 // seen prior to having it's threadObj set (eg JNI attaching threads and
2852 // if vm exit occurs during initialization). These cases can all be accounted
2853 // for such that this method never returns NULL.
2854 const char* JavaThread::get_thread_name() const {
2855 #ifdef ASSERT
2856 // early safepoints can hit while current thread does not yet have TLS
2857 if (!SafepointSynchronize::is_at_safepoint()) {
2858 Thread *cur = Thread::current();
2859 if (!(cur->is_Java_thread() && cur == this)) {
2860 // Current JavaThreads are allowed to get their own name without
2861 // the Threads_lock.
2862 assert_locked_or_safepoint(Threads_lock);
2863 }
2864 }
2865 #endif // ASSERT
2866 return get_thread_name_string();
2867 }
2868
2869 // Returns a non-NULL representation of this thread's name, or a suitable
2870 // descriptive string if there is no set name
2871 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2872 const char* name_str;
2873 oop thread_obj = threadObj();
2874 if (thread_obj != NULL) {
2875 typeArrayOop name = java_lang_Thread::name(thread_obj);
2876 if (name != NULL) {
2877 if (buf == NULL) {
2878 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR),
2879 name->length());
2880 } else {
2881 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR),
2882 name->length(), buf, buflen);
2883 }
2884 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2885 name_str = "<no-name - thread is attaching>";
2886 } else {
2887 name_str = Thread::name();
2888 }
2889 } else {
2890 name_str = Thread::name();
2891 }
2892 assert(name_str != NULL, "unexpected NULL thread name");
2893 return name_str;
2894 }
2895
2896
2897 const char* JavaThread::get_threadgroup_name() const {
2898 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2899 oop thread_obj = threadObj();
2900 if (thread_obj != NULL) {
2901 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2902 if (thread_group != NULL) {
2903 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2904 // ThreadGroup.name can be null
2905 if (name != NULL) {
2906 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2907 return str;
2908 }
2909 }
2910 }
2911 return NULL;
2912 }
2913
2914 const char* JavaThread::get_parent_name() const {
2915 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2916 oop thread_obj = threadObj();
2917 if (thread_obj != NULL) {
2918 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2919 if (thread_group != NULL) {
2920 oop parent = java_lang_ThreadGroup::parent(thread_group);
2921 if (parent != NULL) {
2922 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2923 // ThreadGroup.name can be null
2924 if (name != NULL) {
2925 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2926 return str;
2927 }
2928 }
2929 }
2930 }
2931 return NULL;
2932 }
2933
2934 ThreadPriority JavaThread::java_priority() const {
2935 oop thr_oop = threadObj();
2936 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2937 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2938 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2939 return priority;
2940 }
2941
2942 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2943
2944 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2945 // Link Java Thread object <-> C++ Thread
2946
2947 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2948 // and put it into a new Handle. The Handle "thread_oop" can then
2949 // be used to pass the C++ thread object to other methods.
2950
2951 // Set the Java level thread object (jthread) field of the
2952 // new thread (a JavaThread *) to C++ thread object using the
2953 // "thread_oop" handle.
2954
2955 // Set the thread field (a JavaThread *) of the
2956 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2957
2958 Handle thread_oop(Thread::current(),
2959 JNIHandles::resolve_non_null(jni_thread));
2960 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2961 "must be initialized");
2962 set_threadObj(thread_oop());
2963 java_lang_Thread::set_thread(thread_oop(), this);
2964
2965 if (prio == NoPriority) {
2966 prio = java_lang_Thread::priority(thread_oop());
2967 assert(prio != NoPriority, "A valid priority should be present");
2968 }
2969
2970 // Push the Java priority down to the native thread; needs Threads_lock
2971 Thread::set_priority(this, prio);
2972
2973 prepare_ext();
2974
2975 // Add the new thread to the Threads list and set it in motion.
2976 // We must have threads lock in order to call Threads::add.
2977 // It is crucial that we do not block before the thread is
2978 // added to the Threads list for if a GC happens, then the java_thread oop
2979 // will not be visited by GC.
2980 Threads::add(this);
2981 }
2982
2983 oop JavaThread::current_park_blocker() {
2984 // Support for JSR-166 locks
2985 oop thread_oop = threadObj();
2986 if (thread_oop != NULL &&
2987 JDK_Version::current().supports_thread_park_blocker()) {
2988 return java_lang_Thread::park_blocker(thread_oop);
2989 }
2990 return NULL;
2991 }
2992
2993
2994 void JavaThread::print_stack_on(outputStream* st) {
2995 if (!has_last_Java_frame()) return;
2996 ResourceMark rm;
2997 HandleMark hm;
2998
2999 RegisterMap reg_map(this);
3000 vframe* start_vf = last_java_vframe(®_map);
3001 int count = 0;
3002 for (vframe* f = start_vf; f; f = f->sender()) {
3003 if (f->is_java_frame()) {
3004 javaVFrame* jvf = javaVFrame::cast(f);
3005 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3006
3007 // Print out lock information
3008 if (JavaMonitorsInStackTrace) {
3009 jvf->print_lock_info_on(st, count);
3010 }
3011 } else {
3012 // Ignore non-Java frames
3013 }
3014
3015 // Bail-out case for too deep stacks
3016 count++;
3017 if (MaxJavaStackTraceDepth == count) return;
3018 }
3019 }
3020
3021
3022 // JVMTI PopFrame support
3023 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3024 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3025 if (in_bytes(size_in_bytes) != 0) {
3026 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3027 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3028 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3029 }
3030 }
3031
3032 void* JavaThread::popframe_preserved_args() {
3033 return _popframe_preserved_args;
3034 }
3035
3036 ByteSize JavaThread::popframe_preserved_args_size() {
3037 return in_ByteSize(_popframe_preserved_args_size);
3038 }
3039
3040 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3041 int sz = in_bytes(popframe_preserved_args_size());
3042 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3043 return in_WordSize(sz / wordSize);
3044 }
3045
3046 void JavaThread::popframe_free_preserved_args() {
3047 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3048 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3049 _popframe_preserved_args = NULL;
3050 _popframe_preserved_args_size = 0;
3051 }
3052
3053 #ifndef PRODUCT
3054
3055 void JavaThread::trace_frames() {
3056 tty->print_cr("[Describe stack]");
3057 int frame_no = 1;
3058 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3059 tty->print(" %d. ", frame_no++);
3060 fst.current()->print_value_on(tty, this);
3061 tty->cr();
3062 }
3063 }
3064
3065 class PrintAndVerifyOopClosure: public OopClosure {
3066 protected:
3067 template <class T> inline void do_oop_work(T* p) {
3068 oop obj = oopDesc::load_decode_heap_oop(p);
3069 if (obj == NULL) return;
3070 tty->print(INTPTR_FORMAT ": ", p);
3071 if (obj->is_oop_or_null()) {
3072 if (obj->is_objArray()) {
3073 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3074 } else {
3075 obj->print();
3076 }
3077 } else {
3078 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3079 }
3080 tty->cr();
3081 }
3082 public:
3083 virtual void do_oop(oop* p) { do_oop_work(p); }
3084 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3085 };
3086
3087
3088 static void oops_print(frame* f, const RegisterMap *map) {
3089 PrintAndVerifyOopClosure print;
3090 f->print_value();
3091 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3092 }
3093
3094 // Print our all the locations that contain oops and whether they are
3095 // valid or not. This useful when trying to find the oldest frame
3096 // where an oop has gone bad since the frame walk is from youngest to
3097 // oldest.
3098 void JavaThread::trace_oops() {
3099 tty->print_cr("[Trace oops]");
3100 frames_do(oops_print);
3101 }
3102
3103
3104 #ifdef ASSERT
3105 // Print or validate the layout of stack frames
3106 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3107 ResourceMark rm;
3108 PRESERVE_EXCEPTION_MARK;
3109 FrameValues values;
3110 int frame_no = 0;
3111 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3112 fst.current()->describe(values, ++frame_no);
3113 if (depth == frame_no) break;
3114 }
3115 if (validate_only) {
3116 values.validate();
3117 } else {
3118 tty->print_cr("[Describe stack layout]");
3119 values.print(this);
3120 }
3121 }
3122 #endif
3123
3124 void JavaThread::trace_stack_from(vframe* start_vf) {
3125 ResourceMark rm;
3126 int vframe_no = 1;
3127 for (vframe* f = start_vf; f; f = f->sender()) {
3128 if (f->is_java_frame()) {
3129 javaVFrame::cast(f)->print_activation(vframe_no++);
3130 } else {
3131 f->print();
3132 }
3133 if (vframe_no > StackPrintLimit) {
3134 tty->print_cr("...<more frames>...");
3135 return;
3136 }
3137 }
3138 }
3139
3140
3141 void JavaThread::trace_stack() {
3142 if (!has_last_Java_frame()) return;
3143 ResourceMark rm;
3144 HandleMark hm;
3145 RegisterMap reg_map(this);
3146 trace_stack_from(last_java_vframe(®_map));
3147 }
3148
3149
3150 #endif // PRODUCT
3151
3152
3153 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3154 assert(reg_map != NULL, "a map must be given");
3155 frame f = last_frame();
3156 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3157 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3158 }
3159 return NULL;
3160 }
3161
3162
3163 Klass* JavaThread::security_get_caller_class(int depth) {
3164 vframeStream vfst(this);
3165 vfst.security_get_caller_frame(depth);
3166 if (!vfst.at_end()) {
3167 return vfst.method()->method_holder();
3168 }
3169 return NULL;
3170 }
3171
3172 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3173 assert(thread->is_Compiler_thread(), "must be compiler thread");
3174 CompileBroker::compiler_thread_loop();
3175 }
3176
3177 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3178 NMethodSweeper::sweeper_loop();
3179 }
3180
3181 // Create a CompilerThread
3182 CompilerThread::CompilerThread(CompileQueue* queue,
3183 CompilerCounters* counters)
3184 : JavaThread(&compiler_thread_entry) {
3185 _env = NULL;
3186 _log = NULL;
3187 _task = NULL;
3188 _queue = queue;
3189 _counters = counters;
3190 _buffer_blob = NULL;
3191 _compiler = NULL;
3192
3193 #ifndef PRODUCT
3194 _ideal_graph_printer = NULL;
3195 #endif
3196 }
3197
3198 // Create sweeper thread
3199 CodeCacheSweeperThread::CodeCacheSweeperThread()
3200 : JavaThread(&sweeper_thread_entry) {
3201 _scanned_nmethod = NULL;
3202 }
3203 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3204 JavaThread::oops_do(f, cld_f, cf);
3205 if (_scanned_nmethod != NULL && cf != NULL) {
3206 // Safepoints can occur when the sweeper is scanning an nmethod so
3207 // process it here to make sure it isn't unloaded in the middle of
3208 // a scan.
3209 cf->do_code_blob(_scanned_nmethod);
3210 }
3211 }
3212
3213
3214 // ======= Threads ========
3215
3216 // The Threads class links together all active threads, and provides
3217 // operations over all threads. It is protected by its own Mutex
3218 // lock, which is also used in other contexts to protect thread
3219 // operations from having the thread being operated on from exiting
3220 // and going away unexpectedly (e.g., safepoint synchronization)
3221
3222 JavaThread* Threads::_thread_list = NULL;
3223 int Threads::_number_of_threads = 0;
3224 int Threads::_number_of_non_daemon_threads = 0;
3225 int Threads::_return_code = 0;
3226 size_t JavaThread::_stack_size_at_create = 0;
3227 #ifdef ASSERT
3228 bool Threads::_vm_complete = false;
3229 #endif
3230
3231 // All JavaThreads
3232 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3233
3234 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3235 void Threads::threads_do(ThreadClosure* tc) {
3236 assert_locked_or_safepoint(Threads_lock);
3237 // ALL_JAVA_THREADS iterates through all JavaThreads
3238 ALL_JAVA_THREADS(p) {
3239 tc->do_thread(p);
3240 }
3241 // Someday we could have a table or list of all non-JavaThreads.
3242 // For now, just manually iterate through them.
3243 tc->do_thread(VMThread::vm_thread());
3244 Universe::heap()->gc_threads_do(tc);
3245 WatcherThread *wt = WatcherThread::watcher_thread();
3246 // Strictly speaking, the following NULL check isn't sufficient to make sure
3247 // the data for WatcherThread is still valid upon being examined. However,
3248 // considering that WatchThread terminates when the VM is on the way to
3249 // exit at safepoint, the chance of the above is extremely small. The right
3250 // way to prevent termination of WatcherThread would be to acquire
3251 // Terminator_lock, but we can't do that without violating the lock rank
3252 // checking in some cases.
3253 if (wt != NULL) {
3254 tc->do_thread(wt);
3255 }
3256
3257 // If CompilerThreads ever become non-JavaThreads, add them here
3258 }
3259
3260
3261 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3262 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3263
3264 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3265 create_vm_init_libraries();
3266 }
3267
3268 initialize_class(vmSymbols::java_lang_String(), CHECK);
3269
3270 // Initialize java_lang.System (needed before creating the thread)
3271 initialize_class(vmSymbols::java_lang_System(), CHECK);
3272 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3273 Handle thread_group = create_initial_thread_group(CHECK);
3274 Universe::set_main_thread_group(thread_group());
3275 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3276 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3277 main_thread->set_threadObj(thread_object);
3278 // Set thread status to running since main thread has
3279 // been started and running.
3280 java_lang_Thread::set_thread_status(thread_object,
3281 java_lang_Thread::RUNNABLE);
3282
3283 // The VM creates & returns objects of this class. Make sure it's initialized.
3284 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3285
3286 // The VM preresolves methods to these classes. Make sure that they get initialized
3287 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3288 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3289 call_initializeSystemClass(CHECK);
3290
3291 // get the Java runtime name after java.lang.System is initialized
3292 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3293 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3294
3295 // an instance of OutOfMemory exception has been allocated earlier
3296 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3297 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3298 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3299 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3300 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3301 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3302 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3303 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3304 }
3305
3306 void Threads::initialize_jsr292_core_classes(TRAPS) {
3307 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3308 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3309 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3310 }
3311
3312 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3313 extern void JDK_Version_init();
3314
3315 // Check version
3316 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3317
3318 // Initialize the output stream module
3319 ostream_init();
3320
3321 // Process java launcher properties.
3322 Arguments::process_sun_java_launcher_properties(args);
3323
3324 // Initialize the os module before using TLS
3325 os::init();
3326
3327 // Initialize system properties.
3328 Arguments::init_system_properties();
3329
3330 // So that JDK version can be used as a discriminator when parsing arguments
3331 JDK_Version_init();
3332
3333 // Update/Initialize System properties after JDK version number is known
3334 Arguments::init_version_specific_system_properties();
3335
3336 // Parse arguments
3337 jint parse_result = Arguments::parse(args);
3338 if (parse_result != JNI_OK) return parse_result;
3339
3340 os::init_before_ergo();
3341
3342 jint ergo_result = Arguments::apply_ergo();
3343 if (ergo_result != JNI_OK) return ergo_result;
3344
3345 if (PauseAtStartup) {
3346 os::pause();
3347 }
3348
3349 HOTSPOT_VM_INIT_BEGIN();
3350
3351 // Record VM creation timing statistics
3352 TraceVmCreationTime create_vm_timer;
3353 create_vm_timer.start();
3354
3355 // Timing (must come after argument parsing)
3356 TraceTime timer("Create VM", TraceStartupTime);
3357
3358 // Initialize the os module after parsing the args
3359 jint os_init_2_result = os::init_2();
3360 if (os_init_2_result != JNI_OK) return os_init_2_result;
3361
3362 jint adjust_after_os_result = Arguments::adjust_after_os();
3363 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3364
3365 // initialize TLS
3366 ThreadLocalStorage::init();
3367
3368 // Initialize output stream logging
3369 ostream_init_log();
3370
3371 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3372 // Must be before create_vm_init_agents()
3373 if (Arguments::init_libraries_at_startup()) {
3374 convert_vm_init_libraries_to_agents();
3375 }
3376
3377 // Launch -agentlib/-agentpath and converted -Xrun agents
3378 if (Arguments::init_agents_at_startup()) {
3379 create_vm_init_agents();
3380 }
3381
3382 // Initialize Threads state
3383 _thread_list = NULL;
3384 _number_of_threads = 0;
3385 _number_of_non_daemon_threads = 0;
3386
3387 // Initialize global data structures and create system classes in heap
3388 vm_init_globals();
3389
3390 // Attach the main thread to this os thread
3391 JavaThread* main_thread = new JavaThread();
3392 main_thread->set_thread_state(_thread_in_vm);
3393 // must do this before set_active_handles and initialize_thread_local_storage
3394 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3395 // change the stack size recorded here to one based on the java thread
3396 // stacksize. This adjusted size is what is used to figure the placement
3397 // of the guard pages.
3398 main_thread->record_stack_base_and_size();
3399 main_thread->initialize_thread_local_storage();
3400
3401 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3402
3403 if (!main_thread->set_as_starting_thread()) {
3404 vm_shutdown_during_initialization(
3405 "Failed necessary internal allocation. Out of swap space");
3406 delete main_thread;
3407 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3408 return JNI_ENOMEM;
3409 }
3410
3411 // Enable guard page *after* os::create_main_thread(), otherwise it would
3412 // crash Linux VM, see notes in os_linux.cpp.
3413 main_thread->create_stack_guard_pages();
3414
3415 // Initialize Java-Level synchronization subsystem
3416 ObjectMonitor::Initialize();
3417
3418 // Initialize global modules
3419 jint status = init_globals();
3420 if (status != JNI_OK) {
3421 delete main_thread;
3422 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3423 return status;
3424 }
3425
3426 // Should be done after the heap is fully created
3427 main_thread->cache_global_variables();
3428
3429 HandleMark hm;
3430
3431 { MutexLocker mu(Threads_lock);
3432 Threads::add(main_thread);
3433 }
3434
3435 // Any JVMTI raw monitors entered in onload will transition into
3436 // real raw monitor. VM is setup enough here for raw monitor enter.
3437 JvmtiExport::transition_pending_onload_raw_monitors();
3438
3439 // Create the VMThread
3440 { TraceTime timer("Start VMThread", TraceStartupTime);
3441 VMThread::create();
3442 Thread* vmthread = VMThread::vm_thread();
3443
3444 if (!os::create_thread(vmthread, os::vm_thread)) {
3445 vm_exit_during_initialization("Cannot create VM thread. "
3446 "Out of system resources.");
3447 }
3448
3449 // Wait for the VM thread to become ready, and VMThread::run to initialize
3450 // Monitors can have spurious returns, must always check another state flag
3451 {
3452 MutexLocker ml(Notify_lock);
3453 os::start_thread(vmthread);
3454 while (vmthread->active_handles() == NULL) {
3455 Notify_lock->wait();
3456 }
3457 }
3458 }
3459
3460 assert(Universe::is_fully_initialized(), "not initialized");
3461 if (VerifyDuringStartup) {
3462 // Make sure we're starting with a clean slate.
3463 VM_Verify verify_op;
3464 VMThread::execute(&verify_op);
3465 }
3466
3467 Thread* THREAD = Thread::current();
3468
3469 // At this point, the Universe is initialized, but we have not executed
3470 // any byte code. Now is a good time (the only time) to dump out the
3471 // internal state of the JVM for sharing.
3472 if (DumpSharedSpaces) {
3473 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3474 ShouldNotReachHere();
3475 }
3476
3477 // Always call even when there are not JVMTI environments yet, since environments
3478 // may be attached late and JVMTI must track phases of VM execution
3479 JvmtiExport::enter_start_phase();
3480
3481 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3482 JvmtiExport::post_vm_start();
3483
3484 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3485
3486 // We need this for ClassDataSharing - the initial vm.info property is set
3487 // with the default value of CDS "sharing" which may be reset through
3488 // command line options.
3489 reset_vm_info_property(CHECK_JNI_ERR);
3490
3491 quicken_jni_functions();
3492
3493 // Must be run after init_ft which initializes ft_enabled
3494 if (TRACE_INITIALIZE() != JNI_OK) {
3495 vm_exit_during_initialization("Failed to initialize tracing backend");
3496 }
3497
3498 // Set flag that basic initialization has completed. Used by exceptions and various
3499 // debug stuff, that does not work until all basic classes have been initialized.
3500 set_init_completed();
3501
3502 Metaspace::post_initialize();
3503
3504 HOTSPOT_VM_INIT_END();
3505
3506 // record VM initialization completion time
3507 #if INCLUDE_MANAGEMENT
3508 Management::record_vm_init_completed();
3509 #endif // INCLUDE_MANAGEMENT
3510
3511 // Compute system loader. Note that this has to occur after set_init_completed, since
3512 // valid exceptions may be thrown in the process.
3513 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3514 // set_init_completed has just been called, causing exceptions not to be shortcut
3515 // anymore. We call vm_exit_during_initialization directly instead.
3516 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3517
3518 #if INCLUDE_ALL_GCS
3519 // Support for ConcurrentMarkSweep. This should be cleaned up
3520 // and better encapsulated. The ugly nested if test would go away
3521 // once things are properly refactored. XXX YSR
3522 if (UseConcMarkSweepGC || UseG1GC) {
3523 if (UseConcMarkSweepGC) {
3524 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3525 } else {
3526 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3527 }
3528 }
3529 #endif // INCLUDE_ALL_GCS
3530
3531 // Always call even when there are not JVMTI environments yet, since environments
3532 // may be attached late and JVMTI must track phases of VM execution
3533 JvmtiExport::enter_live_phase();
3534
3535 // Signal Dispatcher needs to be started before VMInit event is posted
3536 os::signal_init();
3537
3538 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3539 if (!DisableAttachMechanism) {
3540 AttachListener::vm_start();
3541 if (StartAttachListener || AttachListener::init_at_startup()) {
3542 AttachListener::init();
3543 }
3544 }
3545
3546 // Launch -Xrun agents
3547 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3548 // back-end can launch with -Xdebug -Xrunjdwp.
3549 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3550 create_vm_init_libraries();
3551 }
3552
3553 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3554 JvmtiExport::post_vm_initialized();
3555
3556 if (TRACE_START() != JNI_OK) {
3557 vm_exit_during_initialization("Failed to start tracing backend.");
3558 }
3559
3560 if (CleanChunkPoolAsync) {
3561 Chunk::start_chunk_pool_cleaner_task();
3562 }
3563
3564 // initialize compiler(s)
3565 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3566 CompileBroker::compilation_init();
3567 #endif
3568
3569 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3570 // It is done after compilers are initialized, because otherwise compilations of
3571 // signature polymorphic MH intrinsics can be missed
3572 // (see SystemDictionary::find_method_handle_intrinsic).
3573 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3574
3575 #if INCLUDE_MANAGEMENT
3576 Management::initialize(THREAD);
3577
3578 if (HAS_PENDING_EXCEPTION) {
3579 // management agent fails to start possibly due to
3580 // configuration problem and is responsible for printing
3581 // stack trace if appropriate. Simply exit VM.
3582 vm_exit(1);
3583 }
3584 #endif // INCLUDE_MANAGEMENT
3585
3586 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3587 if (MemProfiling) MemProfiler::engage();
3588 StatSampler::engage();
3589 if (CheckJNICalls) JniPeriodicChecker::engage();
3590
3591 BiasedLocking::init();
3592
3593 #if INCLUDE_RTM_OPT
3594 RTMLockingCounters::init();
3595 #endif
3596
3597 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3598 call_postVMInitHook(THREAD);
3599 // The Java side of PostVMInitHook.run must deal with all
3600 // exceptions and provide means of diagnosis.
3601 if (HAS_PENDING_EXCEPTION) {
3602 CLEAR_PENDING_EXCEPTION;
3603 }
3604 }
3605
3606 {
3607 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3608 // Make sure the watcher thread can be started by WatcherThread::start()
3609 // or by dynamic enrollment.
3610 WatcherThread::make_startable();
3611 // Start up the WatcherThread if there are any periodic tasks
3612 // NOTE: All PeriodicTasks should be registered by now. If they
3613 // aren't, late joiners might appear to start slowly (we might
3614 // take a while to process their first tick).
3615 if (PeriodicTask::num_tasks() > 0) {
3616 WatcherThread::start();
3617 }
3618 }
3619
3620 create_vm_timer.end();
3621 #ifdef ASSERT
3622 _vm_complete = true;
3623 #endif
3624 return JNI_OK;
3625 }
3626
3627 // type for the Agent_OnLoad and JVM_OnLoad entry points
3628 extern "C" {
3629 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3630 }
3631 // Find a command line agent library and return its entry point for
3632 // -agentlib: -agentpath: -Xrun
3633 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3634 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3635 const char *on_load_symbols[],
3636 size_t num_symbol_entries) {
3637 OnLoadEntry_t on_load_entry = NULL;
3638 void *library = NULL;
3639
3640 if (!agent->valid()) {
3641 char buffer[JVM_MAXPATHLEN];
3642 char ebuf[1024] = "";
3643 const char *name = agent->name();
3644 const char *msg = "Could not find agent library ";
3645
3646 // First check to see if agent is statically linked into executable
3647 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3648 library = agent->os_lib();
3649 } else if (agent->is_absolute_path()) {
3650 library = os::dll_load(name, ebuf, sizeof ebuf);
3651 if (library == NULL) {
3652 const char *sub_msg = " in absolute path, with error: ";
3653 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3654 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3655 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3656 // If we can't find the agent, exit.
3657 vm_exit_during_initialization(buf, NULL);
3658 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3659 }
3660 } else {
3661 // Try to load the agent from the standard dll directory
3662 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3663 name)) {
3664 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3665 }
3666 if (library == NULL) { // Try the local directory
3667 char ns[1] = {0};
3668 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3669 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3670 }
3671 if (library == NULL) {
3672 const char *sub_msg = " on the library path, with error: ";
3673 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3674 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3675 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3676 // If we can't find the agent, exit.
3677 vm_exit_during_initialization(buf, NULL);
3678 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3679 }
3680 }
3681 }
3682 agent->set_os_lib(library);
3683 agent->set_valid();
3684 }
3685
3686 // Find the OnLoad function.
3687 on_load_entry =
3688 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3689 false,
3690 on_load_symbols,
3691 num_symbol_entries));
3692 return on_load_entry;
3693 }
3694
3695 // Find the JVM_OnLoad entry point
3696 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3697 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3698 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3699 }
3700
3701 // Find the Agent_OnLoad entry point
3702 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3703 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3704 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3705 }
3706
3707 // For backwards compatibility with -Xrun
3708 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3709 // treated like -agentpath:
3710 // Must be called before agent libraries are created
3711 void Threads::convert_vm_init_libraries_to_agents() {
3712 AgentLibrary* agent;
3713 AgentLibrary* next;
3714
3715 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3716 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3717 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3718
3719 // If there is an JVM_OnLoad function it will get called later,
3720 // otherwise see if there is an Agent_OnLoad
3721 if (on_load_entry == NULL) {
3722 on_load_entry = lookup_agent_on_load(agent);
3723 if (on_load_entry != NULL) {
3724 // switch it to the agent list -- so that Agent_OnLoad will be called,
3725 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3726 Arguments::convert_library_to_agent(agent);
3727 } else {
3728 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3729 }
3730 }
3731 }
3732 }
3733
3734 // Create agents for -agentlib: -agentpath: and converted -Xrun
3735 // Invokes Agent_OnLoad
3736 // Called very early -- before JavaThreads exist
3737 void Threads::create_vm_init_agents() {
3738 extern struct JavaVM_ main_vm;
3739 AgentLibrary* agent;
3740
3741 JvmtiExport::enter_onload_phase();
3742
3743 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3744 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3745
3746 if (on_load_entry != NULL) {
3747 // Invoke the Agent_OnLoad function
3748 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3749 if (err != JNI_OK) {
3750 vm_exit_during_initialization("agent library failed to init", agent->name());
3751 }
3752 } else {
3753 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3754 }
3755 }
3756 JvmtiExport::enter_primordial_phase();
3757 }
3758
3759 extern "C" {
3760 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3761 }
3762
3763 void Threads::shutdown_vm_agents() {
3764 // Send any Agent_OnUnload notifications
3765 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3766 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3767 extern struct JavaVM_ main_vm;
3768 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3769
3770 // Find the Agent_OnUnload function.
3771 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3772 os::find_agent_function(agent,
3773 false,
3774 on_unload_symbols,
3775 num_symbol_entries));
3776
3777 // Invoke the Agent_OnUnload function
3778 if (unload_entry != NULL) {
3779 JavaThread* thread = JavaThread::current();
3780 ThreadToNativeFromVM ttn(thread);
3781 HandleMark hm(thread);
3782 (*unload_entry)(&main_vm);
3783 }
3784 }
3785 }
3786
3787 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3788 // Invokes JVM_OnLoad
3789 void Threads::create_vm_init_libraries() {
3790 extern struct JavaVM_ main_vm;
3791 AgentLibrary* agent;
3792
3793 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3794 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3795
3796 if (on_load_entry != NULL) {
3797 // Invoke the JVM_OnLoad function
3798 JavaThread* thread = JavaThread::current();
3799 ThreadToNativeFromVM ttn(thread);
3800 HandleMark hm(thread);
3801 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3802 if (err != JNI_OK) {
3803 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3804 }
3805 } else {
3806 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3807 }
3808 }
3809 }
3810
3811 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3812 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3813
3814 JavaThread* java_thread = NULL;
3815 // Sequential search for now. Need to do better optimization later.
3816 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3817 oop tobj = thread->threadObj();
3818 if (!thread->is_exiting() &&
3819 tobj != NULL &&
3820 java_tid == java_lang_Thread::thread_id(tobj)) {
3821 java_thread = thread;
3822 break;
3823 }
3824 }
3825 return java_thread;
3826 }
3827
3828
3829 // Last thread running calls java.lang.Shutdown.shutdown()
3830 void JavaThread::invoke_shutdown_hooks() {
3831 HandleMark hm(this);
3832
3833 // We could get here with a pending exception, if so clear it now.
3834 if (this->has_pending_exception()) {
3835 this->clear_pending_exception();
3836 }
3837
3838 EXCEPTION_MARK;
3839 Klass* k =
3840 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3841 THREAD);
3842 if (k != NULL) {
3843 // SystemDictionary::resolve_or_null will return null if there was
3844 // an exception. If we cannot load the Shutdown class, just don't
3845 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3846 // and finalizers (if runFinalizersOnExit is set) won't be run.
3847 // Note that if a shutdown hook was registered or runFinalizersOnExit
3848 // was called, the Shutdown class would have already been loaded
3849 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3850 instanceKlassHandle shutdown_klass (THREAD, k);
3851 JavaValue result(T_VOID);
3852 JavaCalls::call_static(&result,
3853 shutdown_klass,
3854 vmSymbols::shutdown_method_name(),
3855 vmSymbols::void_method_signature(),
3856 THREAD);
3857 }
3858 CLEAR_PENDING_EXCEPTION;
3859 }
3860
3861 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3862 // the program falls off the end of main(). Another VM exit path is through
3863 // vm_exit() when the program calls System.exit() to return a value or when
3864 // there is a serious error in VM. The two shutdown paths are not exactly
3865 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3866 // and VM_Exit op at VM level.
3867 //
3868 // Shutdown sequence:
3869 // + Shutdown native memory tracking if it is on
3870 // + Wait until we are the last non-daemon thread to execute
3871 // <-- every thing is still working at this moment -->
3872 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3873 // shutdown hooks, run finalizers if finalization-on-exit
3874 // + Call before_exit(), prepare for VM exit
3875 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3876 // currently the only user of this mechanism is File.deleteOnExit())
3877 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3878 // post thread end and vm death events to JVMTI,
3879 // stop signal thread
3880 // + Call JavaThread::exit(), it will:
3881 // > release JNI handle blocks, remove stack guard pages
3882 // > remove this thread from Threads list
3883 // <-- no more Java code from this thread after this point -->
3884 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3885 // the compiler threads at safepoint
3886 // <-- do not use anything that could get blocked by Safepoint -->
3887 // + Disable tracing at JNI/JVM barriers
3888 // + Set _vm_exited flag for threads that are still running native code
3889 // + Delete this thread
3890 // + Call exit_globals()
3891 // > deletes tty
3892 // > deletes PerfMemory resources
3893 // + Return to caller
3894
3895 bool Threads::destroy_vm() {
3896 JavaThread* thread = JavaThread::current();
3897
3898 #ifdef ASSERT
3899 _vm_complete = false;
3900 #endif
3901 // Wait until we are the last non-daemon thread to execute
3902 { MutexLocker nu(Threads_lock);
3903 while (Threads::number_of_non_daemon_threads() > 1)
3904 // This wait should make safepoint checks, wait without a timeout,
3905 // and wait as a suspend-equivalent condition.
3906 //
3907 // Note: If the FlatProfiler is running and this thread is waiting
3908 // for another non-daemon thread to finish, then the FlatProfiler
3909 // is waiting for the external suspend request on this thread to
3910 // complete. wait_for_ext_suspend_completion() will eventually
3911 // timeout, but that takes time. Making this wait a suspend-
3912 // equivalent condition solves that timeout problem.
3913 //
3914 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3915 Mutex::_as_suspend_equivalent_flag);
3916 }
3917
3918 // Hang forever on exit if we are reporting an error.
3919 if (ShowMessageBoxOnError && is_error_reported()) {
3920 os::infinite_sleep();
3921 }
3922 os::wait_for_keypress_at_exit();
3923
3924 // run Java level shutdown hooks
3925 thread->invoke_shutdown_hooks();
3926
3927 before_exit(thread);
3928
3929 thread->exit(true);
3930
3931 // Stop VM thread.
3932 {
3933 // 4945125 The vm thread comes to a safepoint during exit.
3934 // GC vm_operations can get caught at the safepoint, and the
3935 // heap is unparseable if they are caught. Grab the Heap_lock
3936 // to prevent this. The GC vm_operations will not be able to
3937 // queue until after the vm thread is dead. After this point,
3938 // we'll never emerge out of the safepoint before the VM exits.
3939
3940 MutexLocker ml(Heap_lock);
3941
3942 VMThread::wait_for_vm_thread_exit();
3943 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3944 VMThread::destroy();
3945 }
3946
3947 // clean up ideal graph printers
3948 #if defined(COMPILER2) && !defined(PRODUCT)
3949 IdealGraphPrinter::clean_up();
3950 #endif
3951
3952 // Now, all Java threads are gone except daemon threads. Daemon threads
3953 // running Java code or in VM are stopped by the Safepoint. However,
3954 // daemon threads executing native code are still running. But they
3955 // will be stopped at native=>Java/VM barriers. Note that we can't
3956 // simply kill or suspend them, as it is inherently deadlock-prone.
3957
3958 #ifndef PRODUCT
3959 // disable function tracing at JNI/JVM barriers
3960 TraceJNICalls = false;
3961 TraceJVMCalls = false;
3962 TraceRuntimeCalls = false;
3963 #endif
3964
3965 VM_Exit::set_vm_exited();
3966
3967 notify_vm_shutdown();
3968
3969 delete thread;
3970
3971 // exit_globals() will delete tty
3972 exit_globals();
3973
3974 return true;
3975 }
3976
3977
3978 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3979 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3980 return is_supported_jni_version(version);
3981 }
3982
3983
3984 jboolean Threads::is_supported_jni_version(jint version) {
3985 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3986 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3987 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3988 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3989 return JNI_FALSE;
3990 }
3991
3992
3993 void Threads::add(JavaThread* p, bool force_daemon) {
3994 // The threads lock must be owned at this point
3995 assert_locked_or_safepoint(Threads_lock);
3996
3997 // See the comment for this method in thread.hpp for its purpose and
3998 // why it is called here.
3999 p->initialize_queues();
4000 p->set_next(_thread_list);
4001 _thread_list = p;
4002 _number_of_threads++;
4003 oop threadObj = p->threadObj();
4004 bool daemon = true;
4005 // Bootstrapping problem: threadObj can be null for initial
4006 // JavaThread (or for threads attached via JNI)
4007 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4008 _number_of_non_daemon_threads++;
4009 daemon = false;
4010 }
4011
4012 ThreadService::add_thread(p, daemon);
4013
4014 // Possible GC point.
4015 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4016 }
4017
4018 void Threads::remove(JavaThread* p) {
4019 // Extra scope needed for Thread_lock, so we can check
4020 // that we do not remove thread without safepoint code notice
4021 { MutexLocker ml(Threads_lock);
4022
4023 assert(includes(p), "p must be present");
4024
4025 JavaThread* current = _thread_list;
4026 JavaThread* prev = NULL;
4027
4028 while (current != p) {
4029 prev = current;
4030 current = current->next();
4031 }
4032
4033 if (prev) {
4034 prev->set_next(current->next());
4035 } else {
4036 _thread_list = p->next();
4037 }
4038 _number_of_threads--;
4039 oop threadObj = p->threadObj();
4040 bool daemon = true;
4041 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4042 _number_of_non_daemon_threads--;
4043 daemon = false;
4044
4045 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4046 // on destroy_vm will wake up.
4047 if (number_of_non_daemon_threads() == 1) {
4048 Threads_lock->notify_all();
4049 }
4050 }
4051 ThreadService::remove_thread(p, daemon);
4052
4053 // Make sure that safepoint code disregard this thread. This is needed since
4054 // the thread might mess around with locks after this point. This can cause it
4055 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4056 // of this thread since it is removed from the queue.
4057 p->set_terminated_value();
4058 } // unlock Threads_lock
4059
4060 // Since Events::log uses a lock, we grab it outside the Threads_lock
4061 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4062 }
4063
4064 // Threads_lock must be held when this is called (or must be called during a safepoint)
4065 bool Threads::includes(JavaThread* p) {
4066 assert(Threads_lock->is_locked(), "sanity check");
4067 ALL_JAVA_THREADS(q) {
4068 if (q == p) {
4069 return true;
4070 }
4071 }
4072 return false;
4073 }
4074
4075 // Operations on the Threads list for GC. These are not explicitly locked,
4076 // but the garbage collector must provide a safe context for them to run.
4077 // In particular, these things should never be called when the Threads_lock
4078 // is held by some other thread. (Note: the Safepoint abstraction also
4079 // uses the Threads_lock to guarantee this property. It also makes sure that
4080 // all threads gets blocked when exiting or starting).
4081
4082 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4083 ALL_JAVA_THREADS(p) {
4084 p->oops_do(f, cld_f, cf);
4085 }
4086 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4087 }
4088
4089 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4090 // Introduce a mechanism allowing parallel threads to claim threads as
4091 // root groups. Overhead should be small enough to use all the time,
4092 // even in sequential code.
4093 SharedHeap* sh = SharedHeap::heap();
4094 // Cannot yet substitute active_workers for n_par_threads
4095 // because of G1CollectedHeap::verify() use of
4096 // SharedHeap::process_roots(). n_par_threads == 0 will
4097 // turn off parallelism in process_roots while active_workers
4098 // is being used for parallelism elsewhere.
4099 bool is_par = sh->n_par_threads() > 0;
4100 assert(!is_par ||
4101 (SharedHeap::heap()->n_par_threads() ==
4102 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4103 int cp = SharedHeap::heap()->strong_roots_parity();
4104 ALL_JAVA_THREADS(p) {
4105 if (p->claim_oops_do(is_par, cp)) {
4106 p->oops_do(f, cld_f, cf);
4107 }
4108 }
4109 VMThread* vmt = VMThread::vm_thread();
4110 if (vmt->claim_oops_do(is_par, cp)) {
4111 vmt->oops_do(f, cld_f, cf);
4112 }
4113 }
4114
4115 #if INCLUDE_ALL_GCS
4116 // Used by ParallelScavenge
4117 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4118 ALL_JAVA_THREADS(p) {
4119 q->enqueue(new ThreadRootsTask(p));
4120 }
4121 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4122 }
4123
4124 // Used by Parallel Old
4125 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4126 ALL_JAVA_THREADS(p) {
4127 q->enqueue(new ThreadRootsMarkingTask(p));
4128 }
4129 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4130 }
4131 #endif // INCLUDE_ALL_GCS
4132
4133 void Threads::nmethods_do(CodeBlobClosure* cf) {
4134 ALL_JAVA_THREADS(p) {
4135 p->nmethods_do(cf);
4136 }
4137 VMThread::vm_thread()->nmethods_do(cf);
4138 }
4139
4140 void Threads::metadata_do(void f(Metadata*)) {
4141 ALL_JAVA_THREADS(p) {
4142 p->metadata_do(f);
4143 }
4144 }
4145
4146 void Threads::deoptimized_wrt_marked_nmethods() {
4147 ALL_JAVA_THREADS(p) {
4148 p->deoptimized_wrt_marked_nmethods();
4149 }
4150 }
4151
4152
4153 // Get count Java threads that are waiting to enter the specified monitor.
4154 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4155 address monitor,
4156 bool doLock) {
4157 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4158 "must grab Threads_lock or be at safepoint");
4159 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4160
4161 int i = 0;
4162 {
4163 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4164 ALL_JAVA_THREADS(p) {
4165 if (p->is_Compiler_thread()) continue;
4166
4167 address pending = (address)p->current_pending_monitor();
4168 if (pending == monitor) { // found a match
4169 if (i < count) result->append(p); // save the first count matches
4170 i++;
4171 }
4172 }
4173 }
4174 return result;
4175 }
4176
4177
4178 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4179 bool doLock) {
4180 assert(doLock ||
4181 Threads_lock->owned_by_self() ||
4182 SafepointSynchronize::is_at_safepoint(),
4183 "must grab Threads_lock or be at safepoint");
4184
4185 // NULL owner means not locked so we can skip the search
4186 if (owner == NULL) return NULL;
4187
4188 {
4189 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4190 ALL_JAVA_THREADS(p) {
4191 // first, see if owner is the address of a Java thread
4192 if (owner == (address)p) return p;
4193 }
4194 }
4195 // Cannot assert on lack of success here since this function may be
4196 // used by code that is trying to report useful problem information
4197 // like deadlock detection.
4198 if (UseHeavyMonitors) return NULL;
4199
4200 // If we didn't find a matching Java thread and we didn't force use of
4201 // heavyweight monitors, then the owner is the stack address of the
4202 // Lock Word in the owning Java thread's stack.
4203 //
4204 JavaThread* the_owner = NULL;
4205 {
4206 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4207 ALL_JAVA_THREADS(q) {
4208 if (q->is_lock_owned(owner)) {
4209 the_owner = q;
4210 break;
4211 }
4212 }
4213 }
4214 // cannot assert on lack of success here; see above comment
4215 return the_owner;
4216 }
4217
4218 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4219 void Threads::print_on(outputStream* st, bool print_stacks,
4220 bool internal_format, bool print_concurrent_locks) {
4221 char buf[32];
4222 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4223
4224 st->print_cr("Full thread dump %s (%s %s):",
4225 Abstract_VM_Version::vm_name(),
4226 Abstract_VM_Version::vm_release(),
4227 Abstract_VM_Version::vm_info_string());
4228 st->cr();
4229
4230 #if INCLUDE_ALL_GCS
4231 // Dump concurrent locks
4232 ConcurrentLocksDump concurrent_locks;
4233 if (print_concurrent_locks) {
4234 concurrent_locks.dump_at_safepoint();
4235 }
4236 #endif // INCLUDE_ALL_GCS
4237
4238 ALL_JAVA_THREADS(p) {
4239 ResourceMark rm;
4240 p->print_on(st);
4241 if (print_stacks) {
4242 if (internal_format) {
4243 p->trace_stack();
4244 } else {
4245 p->print_stack_on(st);
4246 }
4247 }
4248 st->cr();
4249 #if INCLUDE_ALL_GCS
4250 if (print_concurrent_locks) {
4251 concurrent_locks.print_locks_on(p, st);
4252 }
4253 #endif // INCLUDE_ALL_GCS
4254 }
4255
4256 VMThread::vm_thread()->print_on(st);
4257 st->cr();
4258 Universe::heap()->print_gc_threads_on(st);
4259 WatcherThread* wt = WatcherThread::watcher_thread();
4260 if (wt != NULL) {
4261 wt->print_on(st);
4262 st->cr();
4263 }
4264 CompileBroker::print_compiler_threads_on(st);
4265 st->flush();
4266 }
4267
4268 // Threads::print_on_error() is called by fatal error handler. It's possible
4269 // that VM is not at safepoint and/or current thread is inside signal handler.
4270 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4271 // memory (even in resource area), it might deadlock the error handler.
4272 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4273 int buflen) {
4274 bool found_current = false;
4275 st->print_cr("Java Threads: ( => current thread )");
4276 ALL_JAVA_THREADS(thread) {
4277 bool is_current = (current == thread);
4278 found_current = found_current || is_current;
4279
4280 st->print("%s", is_current ? "=>" : " ");
4281
4282 st->print(PTR_FORMAT, thread);
4283 st->print(" ");
4284 thread->print_on_error(st, buf, buflen);
4285 st->cr();
4286 }
4287 st->cr();
4288
4289 st->print_cr("Other Threads:");
4290 if (VMThread::vm_thread()) {
4291 bool is_current = (current == VMThread::vm_thread());
4292 found_current = found_current || is_current;
4293 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4294
4295 st->print(PTR_FORMAT, VMThread::vm_thread());
4296 st->print(" ");
4297 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4298 st->cr();
4299 }
4300 WatcherThread* wt = WatcherThread::watcher_thread();
4301 if (wt != NULL) {
4302 bool is_current = (current == wt);
4303 found_current = found_current || is_current;
4304 st->print("%s", is_current ? "=>" : " ");
4305
4306 st->print(PTR_FORMAT, wt);
4307 st->print(" ");
4308 wt->print_on_error(st, buf, buflen);
4309 st->cr();
4310 }
4311 if (!found_current) {
4312 st->cr();
4313 st->print("=>" PTR_FORMAT " (exited) ", current);
4314 current->print_on_error(st, buf, buflen);
4315 st->cr();
4316 }
4317 }
4318
4319 // Internal SpinLock and Mutex
4320 // Based on ParkEvent
4321
4322 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4323 //
4324 // We employ SpinLocks _only for low-contention, fixed-length
4325 // short-duration critical sections where we're concerned
4326 // about native mutex_t or HotSpot Mutex:: latency.
4327 // The mux construct provides a spin-then-block mutual exclusion
4328 // mechanism.
4329 //
4330 // Testing has shown that contention on the ListLock guarding gFreeList
4331 // is common. If we implement ListLock as a simple SpinLock it's common
4332 // for the JVM to devolve to yielding with little progress. This is true
4333 // despite the fact that the critical sections protected by ListLock are
4334 // extremely short.
4335 //
4336 // TODO-FIXME: ListLock should be of type SpinLock.
4337 // We should make this a 1st-class type, integrated into the lock
4338 // hierarchy as leaf-locks. Critically, the SpinLock structure
4339 // should have sufficient padding to avoid false-sharing and excessive
4340 // cache-coherency traffic.
4341
4342
4343 typedef volatile int SpinLockT;
4344
4345 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4346 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4347 return; // normal fast-path return
4348 }
4349
4350 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4351 TEVENT(SpinAcquire - ctx);
4352 int ctr = 0;
4353 int Yields = 0;
4354 for (;;) {
4355 while (*adr != 0) {
4356 ++ctr;
4357 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4358 if (Yields > 5) {
4359 os::naked_short_sleep(1);
4360 } else {
4361 os::naked_yield();
4362 ++Yields;
4363 }
4364 } else {
4365 SpinPause();
4366 }
4367 }
4368 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4369 }
4370 }
4371
4372 void Thread::SpinRelease(volatile int * adr) {
4373 assert(*adr != 0, "invariant");
4374 OrderAccess::fence(); // guarantee at least release consistency.
4375 // Roach-motel semantics.
4376 // It's safe if subsequent LDs and STs float "up" into the critical section,
4377 // but prior LDs and STs within the critical section can't be allowed
4378 // to reorder or float past the ST that releases the lock.
4379 // Loads and stores in the critical section - which appear in program
4380 // order before the store that releases the lock - must also appear
4381 // before the store that releases the lock in memory visibility order.
4382 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4383 // the ST of 0 into the lock-word which releases the lock, so fence
4384 // more than covers this on all platforms.
4385 *adr = 0;
4386 }
4387
4388 // muxAcquire and muxRelease:
4389 //
4390 // * muxAcquire and muxRelease support a single-word lock-word construct.
4391 // The LSB of the word is set IFF the lock is held.
4392 // The remainder of the word points to the head of a singly-linked list
4393 // of threads blocked on the lock.
4394 //
4395 // * The current implementation of muxAcquire-muxRelease uses its own
4396 // dedicated Thread._MuxEvent instance. If we're interested in
4397 // minimizing the peak number of extant ParkEvent instances then
4398 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4399 // as certain invariants were satisfied. Specifically, care would need
4400 // to be taken with regards to consuming unpark() "permits".
4401 // A safe rule of thumb is that a thread would never call muxAcquire()
4402 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4403 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4404 // consume an unpark() permit intended for monitorenter, for instance.
4405 // One way around this would be to widen the restricted-range semaphore
4406 // implemented in park(). Another alternative would be to provide
4407 // multiple instances of the PlatformEvent() for each thread. One
4408 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4409 //
4410 // * Usage:
4411 // -- Only as leaf locks
4412 // -- for short-term locking only as muxAcquire does not perform
4413 // thread state transitions.
4414 //
4415 // Alternatives:
4416 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4417 // but with parking or spin-then-park instead of pure spinning.
4418 // * Use Taura-Oyama-Yonenzawa locks.
4419 // * It's possible to construct a 1-0 lock if we encode the lockword as
4420 // (List,LockByte). Acquire will CAS the full lockword while Release
4421 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4422 // acquiring threads use timers (ParkTimed) to detect and recover from
4423 // the stranding window. Thread/Node structures must be aligned on 256-byte
4424 // boundaries by using placement-new.
4425 // * Augment MCS with advisory back-link fields maintained with CAS().
4426 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4427 // The validity of the backlinks must be ratified before we trust the value.
4428 // If the backlinks are invalid the exiting thread must back-track through the
4429 // the forward links, which are always trustworthy.
4430 // * Add a successor indication. The LockWord is currently encoded as
4431 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4432 // to provide the usual futile-wakeup optimization.
4433 // See RTStt for details.
4434 // * Consider schedctl.sc_nopreempt to cover the critical section.
4435 //
4436
4437
4438 typedef volatile intptr_t MutexT; // Mux Lock-word
4439 enum MuxBits { LOCKBIT = 1 };
4440
4441 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4442 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4443 if (w == 0) return;
4444 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4445 return;
4446 }
4447
4448 TEVENT(muxAcquire - Contention);
4449 ParkEvent * const Self = Thread::current()->_MuxEvent;
4450 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4451 for (;;) {
4452 int its = (os::is_MP() ? 100 : 0) + 1;
4453
4454 // Optional spin phase: spin-then-park strategy
4455 while (--its >= 0) {
4456 w = *Lock;
4457 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4458 return;
4459 }
4460 }
4461
4462 Self->reset();
4463 Self->OnList = intptr_t(Lock);
4464 // The following fence() isn't _strictly necessary as the subsequent
4465 // CAS() both serializes execution and ratifies the fetched *Lock value.
4466 OrderAccess::fence();
4467 for (;;) {
4468 w = *Lock;
4469 if ((w & LOCKBIT) == 0) {
4470 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4471 Self->OnList = 0; // hygiene - allows stronger asserts
4472 return;
4473 }
4474 continue; // Interference -- *Lock changed -- Just retry
4475 }
4476 assert(w & LOCKBIT, "invariant");
4477 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4478 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4479 }
4480
4481 while (Self->OnList != 0) {
4482 Self->park();
4483 }
4484 }
4485 }
4486
4487 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4488 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4489 if (w == 0) return;
4490 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4491 return;
4492 }
4493
4494 TEVENT(muxAcquire - Contention);
4495 ParkEvent * ReleaseAfter = NULL;
4496 if (ev == NULL) {
4497 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4498 }
4499 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4500 for (;;) {
4501 guarantee(ev->OnList == 0, "invariant");
4502 int its = (os::is_MP() ? 100 : 0) + 1;
4503
4504 // Optional spin phase: spin-then-park strategy
4505 while (--its >= 0) {
4506 w = *Lock;
4507 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4508 if (ReleaseAfter != NULL) {
4509 ParkEvent::Release(ReleaseAfter);
4510 }
4511 return;
4512 }
4513 }
4514
4515 ev->reset();
4516 ev->OnList = intptr_t(Lock);
4517 // The following fence() isn't _strictly necessary as the subsequent
4518 // CAS() both serializes execution and ratifies the fetched *Lock value.
4519 OrderAccess::fence();
4520 for (;;) {
4521 w = *Lock;
4522 if ((w & LOCKBIT) == 0) {
4523 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4524 ev->OnList = 0;
4525 // We call ::Release while holding the outer lock, thus
4526 // artificially lengthening the critical section.
4527 // Consider deferring the ::Release() until the subsequent unlock(),
4528 // after we've dropped the outer lock.
4529 if (ReleaseAfter != NULL) {
4530 ParkEvent::Release(ReleaseAfter);
4531 }
4532 return;
4533 }
4534 continue; // Interference -- *Lock changed -- Just retry
4535 }
4536 assert(w & LOCKBIT, "invariant");
4537 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4538 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4539 }
4540
4541 while (ev->OnList != 0) {
4542 ev->park();
4543 }
4544 }
4545 }
4546
4547 // Release() must extract a successor from the list and then wake that thread.
4548 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4549 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4550 // Release() would :
4551 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4552 // (B) Extract a successor from the private list "in-hand"
4553 // (C) attempt to CAS() the residual back into *Lock over null.
4554 // If there were any newly arrived threads and the CAS() would fail.
4555 // In that case Release() would detach the RATs, re-merge the list in-hand
4556 // with the RATs and repeat as needed. Alternately, Release() might
4557 // detach and extract a successor, but then pass the residual list to the wakee.
4558 // The wakee would be responsible for reattaching and remerging before it
4559 // competed for the lock.
4560 //
4561 // Both "pop" and DMR are immune from ABA corruption -- there can be
4562 // multiple concurrent pushers, but only one popper or detacher.
4563 // This implementation pops from the head of the list. This is unfair,
4564 // but tends to provide excellent throughput as hot threads remain hot.
4565 // (We wake recently run threads first).
4566 //
4567 // All paths through muxRelease() will execute a CAS.
4568 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4569 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4570 // executed within the critical section are complete and globally visible before the
4571 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4572 void Thread::muxRelease(volatile intptr_t * Lock) {
4573 for (;;) {
4574 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4575 assert(w & LOCKBIT, "invariant");
4576 if (w == LOCKBIT) return;
4577 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4578 assert(List != NULL, "invariant");
4579 assert(List->OnList == intptr_t(Lock), "invariant");
4580 ParkEvent * const nxt = List->ListNext;
4581 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4582
4583 // The following CAS() releases the lock and pops the head element.
4584 // The CAS() also ratifies the previously fetched lock-word value.
4585 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4586 continue;
4587 }
4588 List->OnList = 0;
4589 OrderAccess::fence();
4590 List->unpark();
4591 return;
4592 }
4593 }
4594
4595
4596 void Threads::verify() {
4597 ALL_JAVA_THREADS(p) {
4598 p->verify();
4599 }
4600 VMThread* thread = VMThread::vm_thread();
4601 if (thread != NULL) thread->verify();
4602 }