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, const 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(THREAD, SystemDictionary::ThreadGroup_klass());
1166 Handle threadObj(THREAD, 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 // NamedThread -- non-JavaThread subclasses with multiple
1178 // uniquely named instances should derive from this.
1179 NamedThread::NamedThread() : Thread() {
1180 _name = NULL;
1181 _processed_thread = NULL;
1182 }
1183
1184 NamedThread::~NamedThread() {
1185 if (_name != NULL) {
1186 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1187 _name = NULL;
1188 }
1189 }
1190
1191 void NamedThread::set_name(const char* format, ...) {
1192 guarantee(_name == NULL, "Only get to set name once.");
1193 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1194 guarantee(_name != NULL, "alloc failure");
1195 va_list ap;
1196 va_start(ap, format);
1197 jio_vsnprintf(_name, max_name_len, format, ap);
1198 va_end(ap);
1199 }
1200
1201 void NamedThread::print_on(outputStream* st) const {
1202 st->print("\"%s\" ", name());
1203 Thread::print_on(st);
1204 st->cr();
1205 }
1206
1207
1208 // ======= WatcherThread ========
1209
1210 // The watcher thread exists to simulate timer interrupts. It should
1211 // be replaced by an abstraction over whatever native support for
1212 // timer interrupts exists on the platform.
1213
1214 WatcherThread* WatcherThread::_watcher_thread = NULL;
1215 bool WatcherThread::_startable = false;
1216 volatile bool WatcherThread::_should_terminate = false;
1217
1218 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1219 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1220 if (os::create_thread(this, os::watcher_thread)) {
1221 _watcher_thread = this;
1222
1223 // Set the watcher thread to the highest OS priority which should not be
1224 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1225 // is created. The only normal thread using this priority is the reference
1226 // handler thread, which runs for very short intervals only.
1227 // If the VMThread's priority is not lower than the WatcherThread profiling
1228 // will be inaccurate.
1229 os::set_priority(this, MaxPriority);
1230 if (!DisableStartThread) {
1231 os::start_thread(this);
1232 }
1233 }
1234 }
1235
1236 int WatcherThread::sleep() const {
1237 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1238
1239 // remaining will be zero if there are no tasks,
1240 // causing the WatcherThread to sleep until a task is
1241 // enrolled
1242 int remaining = PeriodicTask::time_to_wait();
1243 int time_slept = 0;
1244
1245 // we expect this to timeout - we only ever get unparked when
1246 // we should terminate or when a new task has been enrolled
1247 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1248
1249 jlong time_before_loop = os::javaTimeNanos();
1250
1251 for (;;) {
1252 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1253 jlong now = os::javaTimeNanos();
1254
1255 if (remaining == 0) {
1256 // if we didn't have any tasks we could have waited for a long time
1257 // consider the time_slept zero and reset time_before_loop
1258 time_slept = 0;
1259 time_before_loop = now;
1260 } else {
1261 // need to recalculate since we might have new tasks in _tasks
1262 time_slept = (int) ((now - time_before_loop) / 1000000);
1263 }
1264
1265 // Change to task list or spurious wakeup of some kind
1266 if (timedout || _should_terminate) {
1267 break;
1268 }
1269
1270 remaining = PeriodicTask::time_to_wait();
1271 if (remaining == 0) {
1272 // Last task was just disenrolled so loop around and wait until
1273 // another task gets enrolled
1274 continue;
1275 }
1276
1277 remaining -= time_slept;
1278 if (remaining <= 0) {
1279 break;
1280 }
1281 }
1282
1283 return time_slept;
1284 }
1285
1286 void WatcherThread::run() {
1287 assert(this == watcher_thread(), "just checking");
1288
1289 this->record_stack_base_and_size();
1290 this->initialize_thread_local_storage();
1291 this->set_native_thread_name(this->name());
1292 this->set_active_handles(JNIHandleBlock::allocate_block());
1293 while (!_should_terminate) {
1294 assert(watcher_thread() == Thread::current(), "thread consistency check");
1295 assert(watcher_thread() == this, "thread consistency check");
1296
1297 // Calculate how long it'll be until the next PeriodicTask work
1298 // should be done, and sleep that amount of time.
1299 int time_waited = sleep();
1300
1301 if (is_error_reported()) {
1302 // A fatal error has happened, the error handler(VMError::report_and_die)
1303 // should abort JVM after creating an error log file. However in some
1304 // rare cases, the error handler itself might deadlock. Here we try to
1305 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1306 //
1307 // This code is in WatcherThread because WatcherThread wakes up
1308 // periodically so the fatal error handler doesn't need to do anything;
1309 // also because the WatcherThread is less likely to crash than other
1310 // threads.
1311
1312 for (;;) {
1313 if (!ShowMessageBoxOnError
1314 && (OnError == NULL || OnError[0] == '\0')
1315 && Arguments::abort_hook() == NULL) {
1316 os::sleep(this, 2 * 60 * 1000, false);
1317 fdStream err(defaultStream::output_fd());
1318 err.print_raw_cr("# [ timer expired, abort... ]");
1319 // skip atexit/vm_exit/vm_abort hooks
1320 os::die();
1321 }
1322
1323 // Wake up 5 seconds later, the fatal handler may reset OnError or
1324 // ShowMessageBoxOnError when it is ready to abort.
1325 os::sleep(this, 5 * 1000, false);
1326 }
1327 }
1328
1329 PeriodicTask::real_time_tick(time_waited);
1330 }
1331
1332 // Signal that it is terminated
1333 {
1334 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1335 _watcher_thread = NULL;
1336 Terminator_lock->notify();
1337 }
1338
1339 // Thread destructor usually does this..
1340 ThreadLocalStorage::set_thread(NULL);
1341 }
1342
1343 void WatcherThread::start() {
1344 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1345
1346 if (watcher_thread() == NULL && _startable) {
1347 _should_terminate = false;
1348 // Create the single instance of WatcherThread
1349 new WatcherThread();
1350 }
1351 }
1352
1353 void WatcherThread::make_startable() {
1354 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1355 _startable = true;
1356 }
1357
1358 void WatcherThread::stop() {
1359 // Get the PeriodicTask_lock if we can. If we cannot, then the
1360 // WatcherThread is using it and we don't want to block on that lock
1361 // here because that might cause a safepoint deadlock depending on
1362 // what the current WatcherThread tasks are doing.
1363 bool have_lock = PeriodicTask_lock->try_lock();
1364
1365 _should_terminate = true;
1366 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1367
1368 if (have_lock) {
1369 WatcherThread* watcher = watcher_thread();
1370 if (watcher != NULL) {
1371 // If we managed to get the lock, then we should unpark the
1372 // WatcherThread so that it can see we want it to stop.
1373 watcher->unpark();
1374 }
1375
1376 PeriodicTask_lock->unlock();
1377 }
1378
1379 // it is ok to take late safepoints here, if needed
1380 MutexLocker mu(Terminator_lock);
1381
1382 while (watcher_thread() != NULL) {
1383 // This wait should make safepoint checks, wait without a timeout,
1384 // and wait as a suspend-equivalent condition.
1385 //
1386 // Note: If the FlatProfiler is running, then this thread is waiting
1387 // for the WatcherThread to terminate and the WatcherThread, via the
1388 // FlatProfiler task, is waiting for the external suspend request on
1389 // this thread to complete. wait_for_ext_suspend_completion() will
1390 // eventually timeout, but that takes time. Making this wait a
1391 // suspend-equivalent condition solves that timeout problem.
1392 //
1393 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1394 Mutex::_as_suspend_equivalent_flag);
1395 }
1396 }
1397
1398 void WatcherThread::unpark() {
1399 MutexLockerEx ml(PeriodicTask_lock->owned_by_self()
1400 ? NULL
1401 : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1402 PeriodicTask_lock->notify();
1403 }
1404
1405 void WatcherThread::print_on(outputStream* st) const {
1406 st->print("\"%s\" ", name());
1407 Thread::print_on(st);
1408 st->cr();
1409 }
1410
1411 // ======= JavaThread ========
1412
1413 // A JavaThread is a normal Java thread
1414
1415 void JavaThread::initialize() {
1416 // Initialize fields
1417
1418 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1419 set_claimed_par_id(UINT_MAX);
1420
1421 set_saved_exception_pc(NULL);
1422 set_threadObj(NULL);
1423 _anchor.clear();
1424 set_entry_point(NULL);
1425 set_jni_functions(jni_functions());
1426 set_callee_target(NULL);
1427 set_vm_result(NULL);
1428 set_vm_result_2(NULL);
1429 set_vframe_array_head(NULL);
1430 set_vframe_array_last(NULL);
1431 set_deferred_locals(NULL);
1432 set_deopt_mark(NULL);
1433 set_deopt_nmethod(NULL);
1434 clear_must_deopt_id();
1435 set_monitor_chunks(NULL);
1436 set_next(NULL);
1437 set_thread_state(_thread_new);
1438 _terminated = _not_terminated;
1439 _privileged_stack_top = NULL;
1440 _array_for_gc = NULL;
1441 _suspend_equivalent = false;
1442 _in_deopt_handler = 0;
1443 _doing_unsafe_access = false;
1444 _stack_guard_state = stack_guard_unused;
1445 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1446 _exception_pc = 0;
1447 _exception_handler_pc = 0;
1448 _is_method_handle_return = 0;
1449 _jvmti_thread_state= NULL;
1450 _should_post_on_exceptions_flag = JNI_FALSE;
1451 _jvmti_get_loaded_classes_closure = NULL;
1452 _interp_only_mode = 0;
1453 _special_runtime_exit_condition = _no_async_condition;
1454 _pending_async_exception = NULL;
1455 _thread_stat = NULL;
1456 _thread_stat = new ThreadStatistics();
1457 _blocked_on_compilation = false;
1458 _jni_active_critical = 0;
1459 _pending_jni_exception_check_fn = NULL;
1460 _do_not_unlock_if_synchronized = false;
1461 _cached_monitor_info = NULL;
1462 _parker = Parker::Allocate(this);
1463
1464 #ifndef PRODUCT
1465 _jmp_ring_index = 0;
1466 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1467 record_jump(NULL, NULL, NULL, 0);
1468 }
1469 #endif // PRODUCT
1470
1471 set_thread_profiler(NULL);
1472 if (FlatProfiler::is_active()) {
1473 // This is where we would decide to either give each thread it's own profiler
1474 // or use one global one from FlatProfiler,
1475 // or up to some count of the number of profiled threads, etc.
1476 ThreadProfiler* pp = new ThreadProfiler();
1477 pp->engage();
1478 set_thread_profiler(pp);
1479 }
1480
1481 // Setup safepoint state info for this thread
1482 ThreadSafepointState::create(this);
1483
1484 debug_only(_java_call_counter = 0);
1485
1486 // JVMTI PopFrame support
1487 _popframe_condition = popframe_inactive;
1488 _popframe_preserved_args = NULL;
1489 _popframe_preserved_args_size = 0;
1490
1491 pd_initialize();
1492 }
1493
1494 #if INCLUDE_ALL_GCS
1495 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1496 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1497 #endif // INCLUDE_ALL_GCS
1498
1499 JavaThread::JavaThread(bool is_attaching_via_jni) :
1500 Thread()
1501 #if INCLUDE_ALL_GCS
1502 , _satb_mark_queue(&_satb_mark_queue_set),
1503 _dirty_card_queue(&_dirty_card_queue_set)
1504 #endif // INCLUDE_ALL_GCS
1505 {
1506 initialize();
1507 if (is_attaching_via_jni) {
1508 _jni_attach_state = _attaching_via_jni;
1509 } else {
1510 _jni_attach_state = _not_attaching_via_jni;
1511 }
1512 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1513 }
1514
1515 bool JavaThread::reguard_stack(address cur_sp) {
1516 if (_stack_guard_state != stack_guard_yellow_disabled) {
1517 return true; // Stack already guarded or guard pages not needed.
1518 }
1519
1520 if (register_stack_overflow()) {
1521 // For those architectures which have separate register and
1522 // memory stacks, we must check the register stack to see if
1523 // it has overflowed.
1524 return false;
1525 }
1526
1527 // Java code never executes within the yellow zone: the latter is only
1528 // there to provoke an exception during stack banging. If java code
1529 // is executing there, either StackShadowPages should be larger, or
1530 // some exception code in c1, c2 or the interpreter isn't unwinding
1531 // when it should.
1532 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1533
1534 enable_stack_yellow_zone();
1535 return true;
1536 }
1537
1538 bool JavaThread::reguard_stack(void) {
1539 return reguard_stack(os::current_stack_pointer());
1540 }
1541
1542
1543 void JavaThread::block_if_vm_exited() {
1544 if (_terminated == _vm_exited) {
1545 // _vm_exited is set at safepoint, and Threads_lock is never released
1546 // we will block here forever
1547 Threads_lock->lock_without_safepoint_check();
1548 ShouldNotReachHere();
1549 }
1550 }
1551
1552
1553 // Remove this ifdef when C1 is ported to the compiler interface.
1554 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1555 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1556
1557 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1558 Thread()
1559 #if INCLUDE_ALL_GCS
1560 , _satb_mark_queue(&_satb_mark_queue_set),
1561 _dirty_card_queue(&_dirty_card_queue_set)
1562 #endif // INCLUDE_ALL_GCS
1563 {
1564 if (TraceThreadEvents) {
1565 tty->print_cr("creating thread %p", this);
1566 }
1567 initialize();
1568 _jni_attach_state = _not_attaching_via_jni;
1569 set_entry_point(entry_point);
1570 // Create the native thread itself.
1571 // %note runtime_23
1572 os::ThreadType thr_type = os::java_thread;
1573 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1574 os::java_thread;
1575 os::create_thread(this, thr_type, stack_sz);
1576 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1577 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1578 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1579 // the exception consists of creating the exception object & initializing it, initialization
1580 // will leave the VM via a JavaCall and then all locks must be unlocked).
1581 //
1582 // The thread is still suspended when we reach here. Thread must be explicit started
1583 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1584 // by calling Threads:add. The reason why this is not done here, is because the thread
1585 // object must be fully initialized (take a look at JVM_Start)
1586 }
1587
1588 JavaThread::~JavaThread() {
1589 if (TraceThreadEvents) {
1590 tty->print_cr("terminate thread %p", this);
1591 }
1592
1593 // JSR166 -- return the parker to the free list
1594 Parker::Release(_parker);
1595 _parker = NULL;
1596
1597 // Free any remaining previous UnrollBlock
1598 vframeArray* old_array = vframe_array_last();
1599
1600 if (old_array != NULL) {
1601 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1602 old_array->set_unroll_block(NULL);
1603 delete old_info;
1604 delete old_array;
1605 }
1606
1607 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1608 if (deferred != NULL) {
1609 // This can only happen if thread is destroyed before deoptimization occurs.
1610 assert(deferred->length() != 0, "empty array!");
1611 do {
1612 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1613 deferred->remove_at(0);
1614 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1615 delete dlv;
1616 } while (deferred->length() != 0);
1617 delete deferred;
1618 }
1619
1620 // All Java related clean up happens in exit
1621 ThreadSafepointState::destroy(this);
1622 if (_thread_profiler != NULL) delete _thread_profiler;
1623 if (_thread_stat != NULL) delete _thread_stat;
1624 }
1625
1626
1627 // The first routine called by a new Java thread
1628 void JavaThread::run() {
1629 // initialize thread-local alloc buffer related fields
1630 this->initialize_tlab();
1631
1632 // used to test validity of stack trace backs
1633 this->record_base_of_stack_pointer();
1634
1635 // Record real stack base and size.
1636 this->record_stack_base_and_size();
1637
1638 // Initialize thread local storage; set before calling MutexLocker
1639 this->initialize_thread_local_storage();
1640
1641 this->create_stack_guard_pages();
1642
1643 this->cache_global_variables();
1644
1645 // Thread is now sufficient initialized to be handled by the safepoint code as being
1646 // in the VM. Change thread state from _thread_new to _thread_in_vm
1647 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1648
1649 assert(JavaThread::current() == this, "sanity check");
1650 assert(!Thread::current()->owns_locks(), "sanity check");
1651
1652 DTRACE_THREAD_PROBE(start, this);
1653
1654 // This operation might block. We call that after all safepoint checks for a new thread has
1655 // been completed.
1656 this->set_active_handles(JNIHandleBlock::allocate_block());
1657
1658 if (JvmtiExport::should_post_thread_life()) {
1659 JvmtiExport::post_thread_start(this);
1660 }
1661
1662 EventThreadStart event;
1663 if (event.should_commit()) {
1664 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1665 event.commit();
1666 }
1667
1668 // We call another function to do the rest so we are sure that the stack addresses used
1669 // from there will be lower than the stack base just computed
1670 thread_main_inner();
1671
1672 // Note, thread is no longer valid at this point!
1673 }
1674
1675
1676 void JavaThread::thread_main_inner() {
1677 assert(JavaThread::current() == this, "sanity check");
1678 assert(this->threadObj() != NULL, "just checking");
1679
1680 // Execute thread entry point unless this thread has a pending exception
1681 // or has been stopped before starting.
1682 // Note: Due to JVM_StopThread we can have pending exceptions already!
1683 if (!this->has_pending_exception() &&
1684 !java_lang_Thread::is_stillborn(this->threadObj())) {
1685 {
1686 ResourceMark rm(this);
1687 this->set_native_thread_name(this->get_thread_name());
1688 }
1689 HandleMark hm(this);
1690 this->entry_point()(this, this);
1691 }
1692
1693 DTRACE_THREAD_PROBE(stop, this);
1694
1695 this->exit(false);
1696 delete this;
1697 }
1698
1699
1700 static void ensure_join(JavaThread* thread) {
1701 // We do not need to grap the Threads_lock, since we are operating on ourself.
1702 Handle threadObj(thread, thread->threadObj());
1703 assert(threadObj.not_null(), "java thread object must exist");
1704 ObjectLocker lock(threadObj, thread);
1705 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1706 thread->clear_pending_exception();
1707 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1708 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1709 // Clear the native thread instance - this makes isAlive return false and allows the join()
1710 // to complete once we've done the notify_all below
1711 java_lang_Thread::set_thread(threadObj(), NULL);
1712 lock.notify_all(thread);
1713 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1714 thread->clear_pending_exception();
1715 }
1716
1717
1718 // For any new cleanup additions, please check to see if they need to be applied to
1719 // cleanup_failed_attach_current_thread as well.
1720 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1721 assert(this == JavaThread::current(), "thread consistency check");
1722
1723 HandleMark hm(this);
1724 Handle uncaught_exception(this, this->pending_exception());
1725 this->clear_pending_exception();
1726 Handle threadObj(this, this->threadObj());
1727 assert(threadObj.not_null(), "Java thread object should be created");
1728
1729 if (get_thread_profiler() != NULL) {
1730 get_thread_profiler()->disengage();
1731 ResourceMark rm;
1732 get_thread_profiler()->print(get_thread_name());
1733 }
1734
1735
1736 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1737 {
1738 EXCEPTION_MARK;
1739
1740 CLEAR_PENDING_EXCEPTION;
1741 }
1742 if (!destroy_vm) {
1743 if (uncaught_exception.not_null()) {
1744 EXCEPTION_MARK;
1745 // Call method Thread.dispatchUncaughtException().
1746 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1747 JavaValue result(T_VOID);
1748 JavaCalls::call_virtual(&result,
1749 threadObj, thread_klass,
1750 vmSymbols::dispatchUncaughtException_name(),
1751 vmSymbols::throwable_void_signature(),
1752 uncaught_exception,
1753 THREAD);
1754 if (HAS_PENDING_EXCEPTION) {
1755 ResourceMark rm(this);
1756 jio_fprintf(defaultStream::error_stream(),
1757 "\nException: %s thrown from the UncaughtExceptionHandler"
1758 " in thread \"%s\"\n",
1759 pending_exception()->klass()->external_name(),
1760 get_thread_name());
1761 CLEAR_PENDING_EXCEPTION;
1762 }
1763 }
1764
1765 // Called before the java thread exit since we want to read info
1766 // from java_lang_Thread object
1767 EventThreadEnd event;
1768 if (event.should_commit()) {
1769 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1770 event.commit();
1771 }
1772
1773 // Call after last event on thread
1774 EVENT_THREAD_EXIT(this);
1775
1776 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1777 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1778 // is deprecated anyhow.
1779 if (!is_Compiler_thread()) {
1780 int count = 3;
1781 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1782 EXCEPTION_MARK;
1783 JavaValue result(T_VOID);
1784 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1785 JavaCalls::call_virtual(&result,
1786 threadObj, thread_klass,
1787 vmSymbols::exit_method_name(),
1788 vmSymbols::void_method_signature(),
1789 THREAD);
1790 CLEAR_PENDING_EXCEPTION;
1791 }
1792 }
1793 // notify JVMTI
1794 if (JvmtiExport::should_post_thread_life()) {
1795 JvmtiExport::post_thread_end(this);
1796 }
1797
1798 // We have notified the agents that we are exiting, before we go on,
1799 // we must check for a pending external suspend request and honor it
1800 // in order to not surprise the thread that made the suspend request.
1801 while (true) {
1802 {
1803 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1804 if (!is_external_suspend()) {
1805 set_terminated(_thread_exiting);
1806 ThreadService::current_thread_exiting(this);
1807 break;
1808 }
1809 // Implied else:
1810 // Things get a little tricky here. We have a pending external
1811 // suspend request, but we are holding the SR_lock so we
1812 // can't just self-suspend. So we temporarily drop the lock
1813 // and then self-suspend.
1814 }
1815
1816 ThreadBlockInVM tbivm(this);
1817 java_suspend_self();
1818
1819 // We're done with this suspend request, but we have to loop around
1820 // and check again. Eventually we will get SR_lock without a pending
1821 // external suspend request and will be able to mark ourselves as
1822 // exiting.
1823 }
1824 // no more external suspends are allowed at this point
1825 } else {
1826 // before_exit() has already posted JVMTI THREAD_END events
1827 }
1828
1829 // Notify waiters on thread object. This has to be done after exit() is called
1830 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1831 // group should have the destroyed bit set before waiters are notified).
1832 ensure_join(this);
1833 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1834
1835 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1836 // held by this thread must be released. A detach operation must only
1837 // get here if there are no Java frames on the stack. Therefore, any
1838 // owned monitors at this point MUST be JNI-acquired monitors which are
1839 // pre-inflated and in the monitor cache.
1840 //
1841 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1842 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1843 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1844 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1845 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1846 }
1847
1848 // These things needs to be done while we are still a Java Thread. Make sure that thread
1849 // is in a consistent state, in case GC happens
1850 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1851
1852 if (active_handles() != NULL) {
1853 JNIHandleBlock* block = active_handles();
1854 set_active_handles(NULL);
1855 JNIHandleBlock::release_block(block);
1856 }
1857
1858 if (free_handle_block() != NULL) {
1859 JNIHandleBlock* block = free_handle_block();
1860 set_free_handle_block(NULL);
1861 JNIHandleBlock::release_block(block);
1862 }
1863
1864 // These have to be removed while this is still a valid thread.
1865 remove_stack_guard_pages();
1866
1867 if (UseTLAB) {
1868 tlab().make_parsable(true); // retire TLAB
1869 }
1870
1871 if (JvmtiEnv::environments_might_exist()) {
1872 JvmtiExport::cleanup_thread(this);
1873 }
1874
1875 // We must flush any deferred card marks before removing a thread from
1876 // the list of active threads.
1877 Universe::heap()->flush_deferred_store_barrier(this);
1878 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1879
1880 #if INCLUDE_ALL_GCS
1881 // We must flush the G1-related buffers before removing a thread
1882 // from the list of active threads. We must do this after any deferred
1883 // card marks have been flushed (above) so that any entries that are
1884 // added to the thread's dirty card queue as a result are not lost.
1885 if (UseG1GC) {
1886 flush_barrier_queues();
1887 }
1888 #endif // INCLUDE_ALL_GCS
1889
1890 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1891 Threads::remove(this);
1892 }
1893
1894 #if INCLUDE_ALL_GCS
1895 // Flush G1-related queues.
1896 void JavaThread::flush_barrier_queues() {
1897 satb_mark_queue().flush();
1898 dirty_card_queue().flush();
1899 }
1900
1901 void JavaThread::initialize_queues() {
1902 assert(!SafepointSynchronize::is_at_safepoint(),
1903 "we should not be at a safepoint");
1904
1905 ObjPtrQueue& satb_queue = satb_mark_queue();
1906 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1907 // The SATB queue should have been constructed with its active
1908 // field set to false.
1909 assert(!satb_queue.is_active(), "SATB queue should not be active");
1910 assert(satb_queue.is_empty(), "SATB queue should be empty");
1911 // If we are creating the thread during a marking cycle, we should
1912 // set the active field of the SATB queue to true.
1913 if (satb_queue_set.is_active()) {
1914 satb_queue.set_active(true);
1915 }
1916
1917 DirtyCardQueue& dirty_queue = dirty_card_queue();
1918 // The dirty card queue should have been constructed with its
1919 // active field set to true.
1920 assert(dirty_queue.is_active(), "dirty card queue should be active");
1921 }
1922 #endif // INCLUDE_ALL_GCS
1923
1924 void JavaThread::cleanup_failed_attach_current_thread() {
1925 if (get_thread_profiler() != NULL) {
1926 get_thread_profiler()->disengage();
1927 ResourceMark rm;
1928 get_thread_profiler()->print(get_thread_name());
1929 }
1930
1931 if (active_handles() != NULL) {
1932 JNIHandleBlock* block = active_handles();
1933 set_active_handles(NULL);
1934 JNIHandleBlock::release_block(block);
1935 }
1936
1937 if (free_handle_block() != NULL) {
1938 JNIHandleBlock* block = free_handle_block();
1939 set_free_handle_block(NULL);
1940 JNIHandleBlock::release_block(block);
1941 }
1942
1943 // These have to be removed while this is still a valid thread.
1944 remove_stack_guard_pages();
1945
1946 if (UseTLAB) {
1947 tlab().make_parsable(true); // retire TLAB, if any
1948 }
1949
1950 #if INCLUDE_ALL_GCS
1951 if (UseG1GC) {
1952 flush_barrier_queues();
1953 }
1954 #endif // INCLUDE_ALL_GCS
1955
1956 Threads::remove(this);
1957 delete this;
1958 }
1959
1960
1961
1962
1963 JavaThread* JavaThread::active() {
1964 Thread* thread = ThreadLocalStorage::thread();
1965 assert(thread != NULL, "just checking");
1966 if (thread->is_Java_thread()) {
1967 return (JavaThread*) thread;
1968 } else {
1969 assert(thread->is_VM_thread(), "this must be a vm thread");
1970 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1971 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1972 assert(ret->is_Java_thread(), "must be a Java thread");
1973 return ret;
1974 }
1975 }
1976
1977 bool JavaThread::is_lock_owned(address adr) const {
1978 if (Thread::is_lock_owned(adr)) return true;
1979
1980 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1981 if (chunk->contains(adr)) return true;
1982 }
1983
1984 return false;
1985 }
1986
1987
1988 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1989 chunk->set_next(monitor_chunks());
1990 set_monitor_chunks(chunk);
1991 }
1992
1993 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1994 guarantee(monitor_chunks() != NULL, "must be non empty");
1995 if (monitor_chunks() == chunk) {
1996 set_monitor_chunks(chunk->next());
1997 } else {
1998 MonitorChunk* prev = monitor_chunks();
1999 while (prev->next() != chunk) prev = prev->next();
2000 prev->set_next(chunk->next());
2001 }
2002 }
2003
2004 // JVM support.
2005
2006 // Note: this function shouldn't block if it's called in
2007 // _thread_in_native_trans state (such as from
2008 // check_special_condition_for_native_trans()).
2009 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2010
2011 if (has_last_Java_frame() && has_async_condition()) {
2012 // If we are at a polling page safepoint (not a poll return)
2013 // then we must defer async exception because live registers
2014 // will be clobbered by the exception path. Poll return is
2015 // ok because the call we a returning from already collides
2016 // with exception handling registers and so there is no issue.
2017 // (The exception handling path kills call result registers but
2018 // this is ok since the exception kills the result anyway).
2019
2020 if (is_at_poll_safepoint()) {
2021 // if the code we are returning to has deoptimized we must defer
2022 // the exception otherwise live registers get clobbered on the
2023 // exception path before deoptimization is able to retrieve them.
2024 //
2025 RegisterMap map(this, false);
2026 frame caller_fr = last_frame().sender(&map);
2027 assert(caller_fr.is_compiled_frame(), "what?");
2028 if (caller_fr.is_deoptimized_frame()) {
2029 if (TraceExceptions) {
2030 ResourceMark rm;
2031 tty->print_cr("deferred async exception at compiled safepoint");
2032 }
2033 return;
2034 }
2035 }
2036 }
2037
2038 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2039 if (condition == _no_async_condition) {
2040 // Conditions have changed since has_special_runtime_exit_condition()
2041 // was called:
2042 // - if we were here only because of an external suspend request,
2043 // then that was taken care of above (or cancelled) so we are done
2044 // - if we were here because of another async request, then it has
2045 // been cleared between the has_special_runtime_exit_condition()
2046 // and now so again we are done
2047 return;
2048 }
2049
2050 // Check for pending async. exception
2051 if (_pending_async_exception != NULL) {
2052 // Only overwrite an already pending exception, if it is not a threadDeath.
2053 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2054
2055 // We cannot call Exceptions::_throw(...) here because we cannot block
2056 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2057
2058 if (TraceExceptions) {
2059 ResourceMark rm;
2060 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2061 if (has_last_Java_frame()) {
2062 frame f = last_frame();
2063 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2064 }
2065 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2066 }
2067 _pending_async_exception = NULL;
2068 clear_has_async_exception();
2069 }
2070 }
2071
2072 if (check_unsafe_error &&
2073 condition == _async_unsafe_access_error && !has_pending_exception()) {
2074 condition = _no_async_condition; // done
2075 switch (thread_state()) {
2076 case _thread_in_vm: {
2077 JavaThread* THREAD = this;
2078 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2079 }
2080 case _thread_in_native: {
2081 ThreadInVMfromNative tiv(this);
2082 JavaThread* THREAD = this;
2083 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2084 }
2085 case _thread_in_Java: {
2086 ThreadInVMfromJava tiv(this);
2087 JavaThread* THREAD = this;
2088 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2089 }
2090 default:
2091 ShouldNotReachHere();
2092 }
2093 }
2094
2095 assert(condition == _no_async_condition || has_pending_exception() ||
2096 (!check_unsafe_error && condition == _async_unsafe_access_error),
2097 "must have handled the async condition, if no exception");
2098 }
2099
2100 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2101 //
2102 // Check for pending external suspend. Internal suspend requests do
2103 // not use handle_special_runtime_exit_condition().
2104 // If JNIEnv proxies are allowed, don't self-suspend if the target
2105 // thread is not the current thread. In older versions of jdbx, jdbx
2106 // threads could call into the VM with another thread's JNIEnv so we
2107 // can be here operating on behalf of a suspended thread (4432884).
2108 bool do_self_suspend = is_external_suspend_with_lock();
2109 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2110 //
2111 // Because thread is external suspended the safepoint code will count
2112 // thread as at a safepoint. This can be odd because we can be here
2113 // as _thread_in_Java which would normally transition to _thread_blocked
2114 // at a safepoint. We would like to mark the thread as _thread_blocked
2115 // before calling java_suspend_self like all other callers of it but
2116 // we must then observe proper safepoint protocol. (We can't leave
2117 // _thread_blocked with a safepoint in progress). However we can be
2118 // here as _thread_in_native_trans so we can't use a normal transition
2119 // constructor/destructor pair because they assert on that type of
2120 // transition. We could do something like:
2121 //
2122 // JavaThreadState state = thread_state();
2123 // set_thread_state(_thread_in_vm);
2124 // {
2125 // ThreadBlockInVM tbivm(this);
2126 // java_suspend_self()
2127 // }
2128 // set_thread_state(_thread_in_vm_trans);
2129 // if (safepoint) block;
2130 // set_thread_state(state);
2131 //
2132 // but that is pretty messy. Instead we just go with the way the
2133 // code has worked before and note that this is the only path to
2134 // java_suspend_self that doesn't put the thread in _thread_blocked
2135 // mode.
2136
2137 frame_anchor()->make_walkable(this);
2138 java_suspend_self();
2139
2140 // We might be here for reasons in addition to the self-suspend request
2141 // so check for other async requests.
2142 }
2143
2144 if (check_asyncs) {
2145 check_and_handle_async_exceptions();
2146 }
2147 }
2148
2149 void JavaThread::send_thread_stop(oop java_throwable) {
2150 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2151 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2152 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2153
2154 // Do not throw asynchronous exceptions against the compiler thread
2155 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2156 if (is_Compiler_thread()) return;
2157
2158 {
2159 // Actually throw the Throwable against the target Thread - however
2160 // only if there is no thread death exception installed already.
2161 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2162 // If the topmost frame is a runtime stub, then we are calling into
2163 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2164 // must deoptimize the caller before continuing, as the compiled exception handler table
2165 // may not be valid
2166 if (has_last_Java_frame()) {
2167 frame f = last_frame();
2168 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2169 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2170 RegisterMap reg_map(this, UseBiasedLocking);
2171 frame compiled_frame = f.sender(®_map);
2172 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2173 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2174 }
2175 }
2176 }
2177
2178 // Set async. pending exception in thread.
2179 set_pending_async_exception(java_throwable);
2180
2181 if (TraceExceptions) {
2182 ResourceMark rm;
2183 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2184 }
2185 // for AbortVMOnException flag
2186 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2187 }
2188 }
2189
2190
2191 // Interrupt thread so it will wake up from a potential wait()
2192 Thread::interrupt(this);
2193 }
2194
2195 // External suspension mechanism.
2196 //
2197 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2198 // to any VM_locks and it is at a transition
2199 // Self-suspension will happen on the transition out of the vm.
2200 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2201 //
2202 // Guarantees on return:
2203 // + Target thread will not execute any new bytecode (that's why we need to
2204 // force a safepoint)
2205 // + Target thread will not enter any new monitors
2206 //
2207 void JavaThread::java_suspend() {
2208 { MutexLocker mu(Threads_lock);
2209 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2210 return;
2211 }
2212 }
2213
2214 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2215 if (!is_external_suspend()) {
2216 // a racing resume has cancelled us; bail out now
2217 return;
2218 }
2219
2220 // suspend is done
2221 uint32_t debug_bits = 0;
2222 // Warning: is_ext_suspend_completed() may temporarily drop the
2223 // SR_lock to allow the thread to reach a stable thread state if
2224 // it is currently in a transient thread state.
2225 if (is_ext_suspend_completed(false /* !called_by_wait */,
2226 SuspendRetryDelay, &debug_bits)) {
2227 return;
2228 }
2229 }
2230
2231 VM_ForceSafepoint vm_suspend;
2232 VMThread::execute(&vm_suspend);
2233 }
2234
2235 // Part II of external suspension.
2236 // A JavaThread self suspends when it detects a pending external suspend
2237 // request. This is usually on transitions. It is also done in places
2238 // where continuing to the next transition would surprise the caller,
2239 // e.g., monitor entry.
2240 //
2241 // Returns the number of times that the thread self-suspended.
2242 //
2243 // Note: DO NOT call java_suspend_self() when you just want to block current
2244 // thread. java_suspend_self() is the second stage of cooperative
2245 // suspension for external suspend requests and should only be used
2246 // to complete an external suspend request.
2247 //
2248 int JavaThread::java_suspend_self() {
2249 int ret = 0;
2250
2251 // we are in the process of exiting so don't suspend
2252 if (is_exiting()) {
2253 clear_external_suspend();
2254 return ret;
2255 }
2256
2257 assert(_anchor.walkable() ||
2258 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2259 "must have walkable stack");
2260
2261 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2262
2263 assert(!this->is_ext_suspended(),
2264 "a thread trying to self-suspend should not already be suspended");
2265
2266 if (this->is_suspend_equivalent()) {
2267 // If we are self-suspending as a result of the lifting of a
2268 // suspend equivalent condition, then the suspend_equivalent
2269 // flag is not cleared until we set the ext_suspended flag so
2270 // that wait_for_ext_suspend_completion() returns consistent
2271 // results.
2272 this->clear_suspend_equivalent();
2273 }
2274
2275 // A racing resume may have cancelled us before we grabbed SR_lock
2276 // above. Or another external suspend request could be waiting for us
2277 // by the time we return from SR_lock()->wait(). The thread
2278 // that requested the suspension may already be trying to walk our
2279 // stack and if we return now, we can change the stack out from under
2280 // it. This would be a "bad thing (TM)" and cause the stack walker
2281 // to crash. We stay self-suspended until there are no more pending
2282 // external suspend requests.
2283 while (is_external_suspend()) {
2284 ret++;
2285 this->set_ext_suspended();
2286
2287 // _ext_suspended flag is cleared by java_resume()
2288 while (is_ext_suspended()) {
2289 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2290 }
2291 }
2292
2293 return ret;
2294 }
2295
2296 #ifdef ASSERT
2297 // verify the JavaThread has not yet been published in the Threads::list, and
2298 // hence doesn't need protection from concurrent access at this stage
2299 void JavaThread::verify_not_published() {
2300 if (!Threads_lock->owned_by_self()) {
2301 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2302 assert(!Threads::includes(this),
2303 "java thread shouldn't have been published yet!");
2304 } else {
2305 assert(!Threads::includes(this),
2306 "java thread shouldn't have been published yet!");
2307 }
2308 }
2309 #endif
2310
2311 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2312 // progress or when _suspend_flags is non-zero.
2313 // Current thread needs to self-suspend if there is a suspend request and/or
2314 // block if a safepoint is in progress.
2315 // Async exception ISN'T checked.
2316 // Note only the ThreadInVMfromNative transition can call this function
2317 // directly and when thread state is _thread_in_native_trans
2318 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2319 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2320
2321 JavaThread *curJT = JavaThread::current();
2322 bool do_self_suspend = thread->is_external_suspend();
2323
2324 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2325
2326 // If JNIEnv proxies are allowed, don't self-suspend if the target
2327 // thread is not the current thread. In older versions of jdbx, jdbx
2328 // threads could call into the VM with another thread's JNIEnv so we
2329 // can be here operating on behalf of a suspended thread (4432884).
2330 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2331 JavaThreadState state = thread->thread_state();
2332
2333 // We mark this thread_blocked state as a suspend-equivalent so
2334 // that a caller to is_ext_suspend_completed() won't be confused.
2335 // The suspend-equivalent state is cleared by java_suspend_self().
2336 thread->set_suspend_equivalent();
2337
2338 // If the safepoint code sees the _thread_in_native_trans state, it will
2339 // wait until the thread changes to other thread state. There is no
2340 // guarantee on how soon we can obtain the SR_lock and complete the
2341 // self-suspend request. It would be a bad idea to let safepoint wait for
2342 // too long. Temporarily change the state to _thread_blocked to
2343 // let the VM thread know that this thread is ready for GC. The problem
2344 // of changing thread state is that safepoint could happen just after
2345 // java_suspend_self() returns after being resumed, and VM thread will
2346 // see the _thread_blocked state. We must check for safepoint
2347 // after restoring the state and make sure we won't leave while a safepoint
2348 // is in progress.
2349 thread->set_thread_state(_thread_blocked);
2350 thread->java_suspend_self();
2351 thread->set_thread_state(state);
2352 // Make sure new state is seen by VM thread
2353 if (os::is_MP()) {
2354 if (UseMembar) {
2355 // Force a fence between the write above and read below
2356 OrderAccess::fence();
2357 } else {
2358 // Must use this rather than serialization page in particular on Windows
2359 InterfaceSupport::serialize_memory(thread);
2360 }
2361 }
2362 }
2363
2364 if (SafepointSynchronize::do_call_back()) {
2365 // If we are safepointing, then block the caller which may not be
2366 // the same as the target thread (see above).
2367 SafepointSynchronize::block(curJT);
2368 }
2369
2370 if (thread->is_deopt_suspend()) {
2371 thread->clear_deopt_suspend();
2372 RegisterMap map(thread, false);
2373 frame f = thread->last_frame();
2374 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2375 f = f.sender(&map);
2376 }
2377 if (f.id() == thread->must_deopt_id()) {
2378 thread->clear_must_deopt_id();
2379 f.deoptimize(thread);
2380 } else {
2381 fatal("missed deoptimization!");
2382 }
2383 }
2384 }
2385
2386 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2387 // progress or when _suspend_flags is non-zero.
2388 // Current thread needs to self-suspend if there is a suspend request and/or
2389 // block if a safepoint is in progress.
2390 // Also check for pending async exception (not including unsafe access error).
2391 // Note only the native==>VM/Java barriers can call this function and when
2392 // thread state is _thread_in_native_trans.
2393 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2394 check_safepoint_and_suspend_for_native_trans(thread);
2395
2396 if (thread->has_async_exception()) {
2397 // We are in _thread_in_native_trans state, don't handle unsafe
2398 // access error since that may block.
2399 thread->check_and_handle_async_exceptions(false);
2400 }
2401 }
2402
2403 // This is a variant of the normal
2404 // check_special_condition_for_native_trans with slightly different
2405 // semantics for use by critical native wrappers. It does all the
2406 // normal checks but also performs the transition back into
2407 // thread_in_Java state. This is required so that critical natives
2408 // can potentially block and perform a GC if they are the last thread
2409 // exiting the GC_locker.
2410 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2411 check_special_condition_for_native_trans(thread);
2412
2413 // Finish the transition
2414 thread->set_thread_state(_thread_in_Java);
2415
2416 if (thread->do_critical_native_unlock()) {
2417 ThreadInVMfromJavaNoAsyncException tiv(thread);
2418 GC_locker::unlock_critical(thread);
2419 thread->clear_critical_native_unlock();
2420 }
2421 }
2422
2423 // We need to guarantee the Threads_lock here, since resumes are not
2424 // allowed during safepoint synchronization
2425 // Can only resume from an external suspension
2426 void JavaThread::java_resume() {
2427 assert_locked_or_safepoint(Threads_lock);
2428
2429 // Sanity check: thread is gone, has started exiting or the thread
2430 // was not externally suspended.
2431 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2432 return;
2433 }
2434
2435 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2436
2437 clear_external_suspend();
2438
2439 if (is_ext_suspended()) {
2440 clear_ext_suspended();
2441 SR_lock()->notify_all();
2442 }
2443 }
2444
2445 void JavaThread::create_stack_guard_pages() {
2446 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2447 address low_addr = stack_base() - stack_size();
2448 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2449
2450 int allocate = os::allocate_stack_guard_pages();
2451 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2452
2453 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2454 warning("Attempt to allocate stack guard pages failed.");
2455 return;
2456 }
2457
2458 if (os::guard_memory((char *) low_addr, len)) {
2459 _stack_guard_state = stack_guard_enabled;
2460 } else {
2461 warning("Attempt to protect stack guard pages failed.");
2462 if (os::uncommit_memory((char *) low_addr, len)) {
2463 warning("Attempt to deallocate stack guard pages failed.");
2464 }
2465 }
2466 }
2467
2468 void JavaThread::remove_stack_guard_pages() {
2469 assert(Thread::current() == this, "from different thread");
2470 if (_stack_guard_state == stack_guard_unused) return;
2471 address low_addr = stack_base() - stack_size();
2472 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2473
2474 if (os::allocate_stack_guard_pages()) {
2475 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2476 _stack_guard_state = stack_guard_unused;
2477 } else {
2478 warning("Attempt to deallocate stack guard pages failed.");
2479 }
2480 } else {
2481 if (_stack_guard_state == stack_guard_unused) return;
2482 if (os::unguard_memory((char *) low_addr, len)) {
2483 _stack_guard_state = stack_guard_unused;
2484 } else {
2485 warning("Attempt to unprotect stack guard pages failed.");
2486 }
2487 }
2488 }
2489
2490 void JavaThread::enable_stack_yellow_zone() {
2491 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2492 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2493
2494 // The base notation is from the stacks point of view, growing downward.
2495 // We need to adjust it to work correctly with guard_memory()
2496 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2497
2498 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2499 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2500
2501 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2502 _stack_guard_state = stack_guard_enabled;
2503 } else {
2504 warning("Attempt to guard stack yellow zone failed.");
2505 }
2506 enable_register_stack_guard();
2507 }
2508
2509 void JavaThread::disable_stack_yellow_zone() {
2510 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2511 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2512
2513 // Simply return if called for a thread that does not use guard pages.
2514 if (_stack_guard_state == stack_guard_unused) return;
2515
2516 // The base notation is from the stacks point of view, growing downward.
2517 // We need to adjust it to work correctly with guard_memory()
2518 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2519
2520 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2521 _stack_guard_state = stack_guard_yellow_disabled;
2522 } else {
2523 warning("Attempt to unguard stack yellow zone failed.");
2524 }
2525 disable_register_stack_guard();
2526 }
2527
2528 void JavaThread::enable_stack_red_zone() {
2529 // The base notation is from the stacks point of view, growing downward.
2530 // We need to adjust it to work correctly with guard_memory()
2531 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2532 address base = stack_red_zone_base() - stack_red_zone_size();
2533
2534 guarantee(base < stack_base(), "Error calculating stack red zone");
2535 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2536
2537 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2538 warning("Attempt to guard stack red zone failed.");
2539 }
2540 }
2541
2542 void JavaThread::disable_stack_red_zone() {
2543 // The base notation is from the stacks point of view, growing downward.
2544 // We need to adjust it to work correctly with guard_memory()
2545 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2546 address base = stack_red_zone_base() - stack_red_zone_size();
2547 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2548 warning("Attempt to unguard stack red zone failed.");
2549 }
2550 }
2551
2552 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2553 // ignore is there is no stack
2554 if (!has_last_Java_frame()) return;
2555 // traverse the stack frames. Starts from top frame.
2556 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2557 frame* fr = fst.current();
2558 f(fr, fst.register_map());
2559 }
2560 }
2561
2562
2563 #ifndef PRODUCT
2564 // Deoptimization
2565 // Function for testing deoptimization
2566 void JavaThread::deoptimize() {
2567 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2568 StackFrameStream fst(this, UseBiasedLocking);
2569 bool deopt = false; // Dump stack only if a deopt actually happens.
2570 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2571 // Iterate over all frames in the thread and deoptimize
2572 for (; !fst.is_done(); fst.next()) {
2573 if (fst.current()->can_be_deoptimized()) {
2574
2575 if (only_at) {
2576 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2577 // consists of comma or carriage return separated numbers so
2578 // search for the current bci in that string.
2579 address pc = fst.current()->pc();
2580 nmethod* nm = (nmethod*) fst.current()->cb();
2581 ScopeDesc* sd = nm->scope_desc_at(pc);
2582 char buffer[8];
2583 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2584 size_t len = strlen(buffer);
2585 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2586 while (found != NULL) {
2587 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2588 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2589 // Check that the bci found is bracketed by terminators.
2590 break;
2591 }
2592 found = strstr(found + 1, buffer);
2593 }
2594 if (!found) {
2595 continue;
2596 }
2597 }
2598
2599 if (DebugDeoptimization && !deopt) {
2600 deopt = true; // One-time only print before deopt
2601 tty->print_cr("[BEFORE Deoptimization]");
2602 trace_frames();
2603 trace_stack();
2604 }
2605 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2606 }
2607 }
2608
2609 if (DebugDeoptimization && deopt) {
2610 tty->print_cr("[AFTER Deoptimization]");
2611 trace_frames();
2612 }
2613 }
2614
2615
2616 // Make zombies
2617 void JavaThread::make_zombies() {
2618 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2619 if (fst.current()->can_be_deoptimized()) {
2620 // it is a Java nmethod
2621 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2622 nm->make_not_entrant();
2623 }
2624 }
2625 }
2626 #endif // PRODUCT
2627
2628
2629 void JavaThread::deoptimized_wrt_marked_nmethods() {
2630 if (!has_last_Java_frame()) return;
2631 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2632 StackFrameStream fst(this, UseBiasedLocking);
2633 for (; !fst.is_done(); fst.next()) {
2634 if (fst.current()->should_be_deoptimized()) {
2635 if (LogCompilation && xtty != NULL) {
2636 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2637 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2638 this->name(), nm != NULL ? nm->compile_id() : -1);
2639 }
2640
2641 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2642 }
2643 }
2644 }
2645
2646
2647 // If the caller is a NamedThread, then remember, in the current scope,
2648 // the given JavaThread in its _processed_thread field.
2649 class RememberProcessedThread: public StackObj {
2650 NamedThread* _cur_thr;
2651 public:
2652 RememberProcessedThread(JavaThread* jthr) {
2653 Thread* thread = Thread::current();
2654 if (thread->is_Named_thread()) {
2655 _cur_thr = (NamedThread *)thread;
2656 _cur_thr->set_processed_thread(jthr);
2657 } else {
2658 _cur_thr = NULL;
2659 }
2660 }
2661
2662 ~RememberProcessedThread() {
2663 if (_cur_thr) {
2664 _cur_thr->set_processed_thread(NULL);
2665 }
2666 }
2667 };
2668
2669 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2670 // Verify that the deferred card marks have been flushed.
2671 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2672
2673 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2674 // since there may be more than one thread using each ThreadProfiler.
2675
2676 // Traverse the GCHandles
2677 Thread::oops_do(f, cld_f, cf);
2678
2679 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2680 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2681
2682 if (has_last_Java_frame()) {
2683 // Record JavaThread to GC thread
2684 RememberProcessedThread rpt(this);
2685
2686 // Traverse the privileged stack
2687 if (_privileged_stack_top != NULL) {
2688 _privileged_stack_top->oops_do(f);
2689 }
2690
2691 // traverse the registered growable array
2692 if (_array_for_gc != NULL) {
2693 for (int index = 0; index < _array_for_gc->length(); index++) {
2694 f->do_oop(_array_for_gc->adr_at(index));
2695 }
2696 }
2697
2698 // Traverse the monitor chunks
2699 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2700 chunk->oops_do(f);
2701 }
2702
2703 // Traverse the execution stack
2704 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2705 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2706 }
2707 }
2708
2709 // callee_target is never live across a gc point so NULL it here should
2710 // it still contain a methdOop.
2711
2712 set_callee_target(NULL);
2713
2714 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2715 // If we have deferred set_locals there might be oops waiting to be
2716 // written
2717 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2718 if (list != NULL) {
2719 for (int i = 0; i < list->length(); i++) {
2720 list->at(i)->oops_do(f);
2721 }
2722 }
2723
2724 // Traverse instance variables at the end since the GC may be moving things
2725 // around using this function
2726 f->do_oop((oop*) &_threadObj);
2727 f->do_oop((oop*) &_vm_result);
2728 f->do_oop((oop*) &_exception_oop);
2729 f->do_oop((oop*) &_pending_async_exception);
2730
2731 if (jvmti_thread_state() != NULL) {
2732 jvmti_thread_state()->oops_do(f);
2733 }
2734 }
2735
2736 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2737 Thread::nmethods_do(cf); // (super method is a no-op)
2738
2739 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2740 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2741
2742 if (has_last_Java_frame()) {
2743 // Traverse the execution stack
2744 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2745 fst.current()->nmethods_do(cf);
2746 }
2747 }
2748 }
2749
2750 void JavaThread::metadata_do(void f(Metadata*)) {
2751 Thread::metadata_do(f);
2752 if (has_last_Java_frame()) {
2753 // Traverse the execution stack to call f() on the methods in the stack
2754 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2755 fst.current()->metadata_do(f);
2756 }
2757 } else if (is_Compiler_thread()) {
2758 // need to walk ciMetadata in current compile tasks to keep alive.
2759 CompilerThread* ct = (CompilerThread*)this;
2760 if (ct->env() != NULL) {
2761 ct->env()->metadata_do(f);
2762 }
2763 }
2764 }
2765
2766 // Printing
2767 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2768 switch (_thread_state) {
2769 case _thread_uninitialized: return "_thread_uninitialized";
2770 case _thread_new: return "_thread_new";
2771 case _thread_new_trans: return "_thread_new_trans";
2772 case _thread_in_native: return "_thread_in_native";
2773 case _thread_in_native_trans: return "_thread_in_native_trans";
2774 case _thread_in_vm: return "_thread_in_vm";
2775 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2776 case _thread_in_Java: return "_thread_in_Java";
2777 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2778 case _thread_blocked: return "_thread_blocked";
2779 case _thread_blocked_trans: return "_thread_blocked_trans";
2780 default: return "unknown thread state";
2781 }
2782 }
2783
2784 #ifndef PRODUCT
2785 void JavaThread::print_thread_state_on(outputStream *st) const {
2786 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2787 };
2788 void JavaThread::print_thread_state() const {
2789 print_thread_state_on(tty);
2790 }
2791 #endif // PRODUCT
2792
2793 // Called by Threads::print() for VM_PrintThreads operation
2794 void JavaThread::print_on(outputStream *st) const {
2795 st->print("\"%s\" ", get_thread_name());
2796 oop thread_oop = threadObj();
2797 if (thread_oop != NULL) {
2798 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2799 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2800 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2801 }
2802 Thread::print_on(st);
2803 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2804 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2805 if (thread_oop != NULL) {
2806 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2807 }
2808 #ifndef PRODUCT
2809 print_thread_state_on(st);
2810 _safepoint_state->print_on(st);
2811 #endif // PRODUCT
2812 }
2813
2814 // Called by fatal error handler. The difference between this and
2815 // JavaThread::print() is that we can't grab lock or allocate memory.
2816 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2817 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2818 oop thread_obj = threadObj();
2819 if (thread_obj != NULL) {
2820 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2821 }
2822 st->print(" [");
2823 st->print("%s", _get_thread_state_name(_thread_state));
2824 if (osthread()) {
2825 st->print(", id=%d", osthread()->thread_id());
2826 }
2827 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2828 _stack_base - _stack_size, _stack_base);
2829 st->print("]");
2830 return;
2831 }
2832
2833 // Verification
2834
2835 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2836
2837 void JavaThread::verify() {
2838 // Verify oops in the thread.
2839 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2840
2841 // Verify the stack frames.
2842 frames_do(frame_verify);
2843 }
2844
2845 // CR 6300358 (sub-CR 2137150)
2846 // Most callers of this method assume that it can't return NULL but a
2847 // thread may not have a name whilst it is in the process of attaching to
2848 // the VM - see CR 6412693, and there are places where a JavaThread can be
2849 // seen prior to having it's threadObj set (eg JNI attaching threads and
2850 // if vm exit occurs during initialization). These cases can all be accounted
2851 // for such that this method never returns NULL.
2852 const char* JavaThread::get_thread_name() const {
2853 #ifdef ASSERT
2854 // early safepoints can hit while current thread does not yet have TLS
2855 if (!SafepointSynchronize::is_at_safepoint()) {
2856 Thread *cur = Thread::current();
2857 if (!(cur->is_Java_thread() && cur == this)) {
2858 // Current JavaThreads are allowed to get their own name without
2859 // the Threads_lock.
2860 assert_locked_or_safepoint(Threads_lock);
2861 }
2862 }
2863 #endif // ASSERT
2864 return get_thread_name_string();
2865 }
2866
2867 // Returns a non-NULL representation of this thread's name, or a suitable
2868 // descriptive string if there is no set name
2869 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2870 const char* name_str;
2871 oop thread_obj = threadObj();
2872 if (thread_obj != NULL) {
2873 typeArrayOop name = java_lang_Thread::name(thread_obj);
2874 if (name != NULL) {
2875 if (buf == NULL) {
2876 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR),
2877 name->length());
2878 } else {
2879 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR),
2880 name->length(), buf, buflen);
2881 }
2882 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2883 name_str = "<no-name - thread is attaching>";
2884 } else {
2885 name_str = Thread::name();
2886 }
2887 } else {
2888 name_str = Thread::name();
2889 }
2890 assert(name_str != NULL, "unexpected NULL thread name");
2891 return name_str;
2892 }
2893
2894
2895 const char* JavaThread::get_threadgroup_name() const {
2896 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2897 oop thread_obj = threadObj();
2898 if (thread_obj != NULL) {
2899 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2900 if (thread_group != NULL) {
2901 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2902 // ThreadGroup.name can be null
2903 if (name != NULL) {
2904 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2905 return str;
2906 }
2907 }
2908 }
2909 return NULL;
2910 }
2911
2912 const char* JavaThread::get_parent_name() const {
2913 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2914 oop thread_obj = threadObj();
2915 if (thread_obj != NULL) {
2916 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2917 if (thread_group != NULL) {
2918 oop parent = java_lang_ThreadGroup::parent(thread_group);
2919 if (parent != NULL) {
2920 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2921 // ThreadGroup.name can be null
2922 if (name != NULL) {
2923 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2924 return str;
2925 }
2926 }
2927 }
2928 }
2929 return NULL;
2930 }
2931
2932 ThreadPriority JavaThread::java_priority() const {
2933 oop thr_oop = threadObj();
2934 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2935 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2936 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2937 return priority;
2938 }
2939
2940 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2941
2942 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2943 // Link Java Thread object <-> C++ Thread
2944
2945 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2946 // and put it into a new Handle. The Handle "thread_oop" can then
2947 // be used to pass the C++ thread object to other methods.
2948
2949 // Set the Java level thread object (jthread) field of the
2950 // new thread (a JavaThread *) to C++ thread object using the
2951 // "thread_oop" handle.
2952
2953 // Set the thread field (a JavaThread *) of the
2954 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2955
2956 Handle thread_oop(Thread::current(),
2957 JNIHandles::resolve_non_null(jni_thread));
2958 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2959 "must be initialized");
2960 set_threadObj(thread_oop());
2961 java_lang_Thread::set_thread(thread_oop(), this);
2962
2963 if (prio == NoPriority) {
2964 prio = java_lang_Thread::priority(thread_oop());
2965 assert(prio != NoPriority, "A valid priority should be present");
2966 }
2967
2968 // Push the Java priority down to the native thread; needs Threads_lock
2969 Thread::set_priority(this, prio);
2970
2971 prepare_ext();
2972
2973 // Add the new thread to the Threads list and set it in motion.
2974 // We must have threads lock in order to call Threads::add.
2975 // It is crucial that we do not block before the thread is
2976 // added to the Threads list for if a GC happens, then the java_thread oop
2977 // will not be visited by GC.
2978 Threads::add(this);
2979 }
2980
2981 oop JavaThread::current_park_blocker() {
2982 // Support for JSR-166 locks
2983 oop thread_oop = threadObj();
2984 if (thread_oop != NULL &&
2985 JDK_Version::current().supports_thread_park_blocker()) {
2986 return java_lang_Thread::park_blocker(thread_oop);
2987 }
2988 return NULL;
2989 }
2990
2991
2992 void JavaThread::print_stack_on(outputStream* st) {
2993 if (!has_last_Java_frame()) return;
2994 ResourceMark rm;
2995 HandleMark hm;
2996
2997 RegisterMap reg_map(this);
2998 vframe* start_vf = last_java_vframe(®_map);
2999 int count = 0;
3000 for (vframe* f = start_vf; f; f = f->sender()) {
3001 if (f->is_java_frame()) {
3002 javaVFrame* jvf = javaVFrame::cast(f);
3003 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3004
3005 // Print out lock information
3006 if (JavaMonitorsInStackTrace) {
3007 jvf->print_lock_info_on(st, count);
3008 }
3009 } else {
3010 // Ignore non-Java frames
3011 }
3012
3013 // Bail-out case for too deep stacks
3014 count++;
3015 if (MaxJavaStackTraceDepth == count) return;
3016 }
3017 }
3018
3019
3020 // JVMTI PopFrame support
3021 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3022 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3023 if (in_bytes(size_in_bytes) != 0) {
3024 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3025 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3026 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3027 }
3028 }
3029
3030 void* JavaThread::popframe_preserved_args() {
3031 return _popframe_preserved_args;
3032 }
3033
3034 ByteSize JavaThread::popframe_preserved_args_size() {
3035 return in_ByteSize(_popframe_preserved_args_size);
3036 }
3037
3038 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3039 int sz = in_bytes(popframe_preserved_args_size());
3040 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3041 return in_WordSize(sz / wordSize);
3042 }
3043
3044 void JavaThread::popframe_free_preserved_args() {
3045 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3046 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3047 _popframe_preserved_args = NULL;
3048 _popframe_preserved_args_size = 0;
3049 }
3050
3051 #ifndef PRODUCT
3052
3053 void JavaThread::trace_frames() {
3054 tty->print_cr("[Describe stack]");
3055 int frame_no = 1;
3056 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3057 tty->print(" %d. ", frame_no++);
3058 fst.current()->print_value_on(tty, this);
3059 tty->cr();
3060 }
3061 }
3062
3063 class PrintAndVerifyOopClosure: public OopClosure {
3064 protected:
3065 template <class T> inline void do_oop_work(T* p) {
3066 oop obj = oopDesc::load_decode_heap_oop(p);
3067 if (obj == NULL) return;
3068 tty->print(INTPTR_FORMAT ": ", p);
3069 if (obj->is_oop_or_null()) {
3070 if (obj->is_objArray()) {
3071 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3072 } else {
3073 obj->print();
3074 }
3075 } else {
3076 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3077 }
3078 tty->cr();
3079 }
3080 public:
3081 virtual void do_oop(oop* p) { do_oop_work(p); }
3082 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3083 };
3084
3085
3086 static void oops_print(frame* f, const RegisterMap *map) {
3087 PrintAndVerifyOopClosure print;
3088 f->print_value();
3089 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3090 }
3091
3092 // Print our all the locations that contain oops and whether they are
3093 // valid or not. This useful when trying to find the oldest frame
3094 // where an oop has gone bad since the frame walk is from youngest to
3095 // oldest.
3096 void JavaThread::trace_oops() {
3097 tty->print_cr("[Trace oops]");
3098 frames_do(oops_print);
3099 }
3100
3101
3102 #ifdef ASSERT
3103 // Print or validate the layout of stack frames
3104 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3105 ResourceMark rm;
3106 PRESERVE_EXCEPTION_MARK;
3107 FrameValues values;
3108 int frame_no = 0;
3109 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3110 fst.current()->describe(values, ++frame_no);
3111 if (depth == frame_no) break;
3112 }
3113 if (validate_only) {
3114 values.validate();
3115 } else {
3116 tty->print_cr("[Describe stack layout]");
3117 values.print(this);
3118 }
3119 }
3120 #endif
3121
3122 void JavaThread::trace_stack_from(vframe* start_vf) {
3123 ResourceMark rm;
3124 int vframe_no = 1;
3125 for (vframe* f = start_vf; f; f = f->sender()) {
3126 if (f->is_java_frame()) {
3127 javaVFrame::cast(f)->print_activation(vframe_no++);
3128 } else {
3129 f->print();
3130 }
3131 if (vframe_no > StackPrintLimit) {
3132 tty->print_cr("...<more frames>...");
3133 return;
3134 }
3135 }
3136 }
3137
3138
3139 void JavaThread::trace_stack() {
3140 if (!has_last_Java_frame()) return;
3141 ResourceMark rm;
3142 HandleMark hm;
3143 RegisterMap reg_map(this);
3144 trace_stack_from(last_java_vframe(®_map));
3145 }
3146
3147
3148 #endif // PRODUCT
3149
3150
3151 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3152 assert(reg_map != NULL, "a map must be given");
3153 frame f = last_frame();
3154 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3155 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3156 }
3157 return NULL;
3158 }
3159
3160
3161 Klass* JavaThread::security_get_caller_class(int depth) {
3162 vframeStream vfst(this);
3163 vfst.security_get_caller_frame(depth);
3164 if (!vfst.at_end()) {
3165 return vfst.method()->method_holder();
3166 }
3167 return NULL;
3168 }
3169
3170 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3171 assert(thread->is_Compiler_thread(), "must be compiler thread");
3172 CompileBroker::compiler_thread_loop();
3173 }
3174
3175 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3176 NMethodSweeper::sweeper_loop();
3177 }
3178
3179 // Create a CompilerThread
3180 CompilerThread::CompilerThread(CompileQueue* queue,
3181 CompilerCounters* counters)
3182 : JavaThread(&compiler_thread_entry) {
3183 _env = NULL;
3184 _log = NULL;
3185 _task = NULL;
3186 _queue = queue;
3187 _counters = counters;
3188 _buffer_blob = NULL;
3189 _compiler = NULL;
3190
3191 #ifndef PRODUCT
3192 _ideal_graph_printer = NULL;
3193 #endif
3194 }
3195
3196 // Create sweeper thread
3197 CodeCacheSweeperThread::CodeCacheSweeperThread()
3198 : JavaThread(&sweeper_thread_entry) {
3199 _scanned_nmethod = NULL;
3200 }
3201 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3202 JavaThread::oops_do(f, cld_f, cf);
3203 if (_scanned_nmethod != NULL && cf != NULL) {
3204 // Safepoints can occur when the sweeper is scanning an nmethod so
3205 // process it here to make sure it isn't unloaded in the middle of
3206 // a scan.
3207 cf->do_code_blob(_scanned_nmethod);
3208 }
3209 }
3210
3211
3212 // ======= Threads ========
3213
3214 // The Threads class links together all active threads, and provides
3215 // operations over all threads. It is protected by its own Mutex
3216 // lock, which is also used in other contexts to protect thread
3217 // operations from having the thread being operated on from exiting
3218 // and going away unexpectedly (e.g., safepoint synchronization)
3219
3220 JavaThread* Threads::_thread_list = NULL;
3221 int Threads::_number_of_threads = 0;
3222 int Threads::_number_of_non_daemon_threads = 0;
3223 int Threads::_return_code = 0;
3224 size_t JavaThread::_stack_size_at_create = 0;
3225 #ifdef ASSERT
3226 bool Threads::_vm_complete = false;
3227 #endif
3228
3229 // All JavaThreads
3230 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3231
3232 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3233 void Threads::threads_do(ThreadClosure* tc) {
3234 assert_locked_or_safepoint(Threads_lock);
3235 // ALL_JAVA_THREADS iterates through all JavaThreads
3236 ALL_JAVA_THREADS(p) {
3237 tc->do_thread(p);
3238 }
3239 // Someday we could have a table or list of all non-JavaThreads.
3240 // For now, just manually iterate through them.
3241 tc->do_thread(VMThread::vm_thread());
3242 Universe::heap()->gc_threads_do(tc);
3243 WatcherThread *wt = WatcherThread::watcher_thread();
3244 // Strictly speaking, the following NULL check isn't sufficient to make sure
3245 // the data for WatcherThread is still valid upon being examined. However,
3246 // considering that WatchThread terminates when the VM is on the way to
3247 // exit at safepoint, the chance of the above is extremely small. The right
3248 // way to prevent termination of WatcherThread would be to acquire
3249 // Terminator_lock, but we can't do that without violating the lock rank
3250 // checking in some cases.
3251 if (wt != NULL) {
3252 tc->do_thread(wt);
3253 }
3254
3255 // If CompilerThreads ever become non-JavaThreads, add them here
3256 }
3257
3258
3259 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3260 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3261
3262 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3263 create_vm_init_libraries();
3264 }
3265
3266 initialize_class(vmSymbols::java_lang_String(), CHECK);
3267
3268 // Initialize java_lang.System (needed before creating the thread)
3269 initialize_class(vmSymbols::java_lang_System(), CHECK);
3270 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3271 Handle thread_group = create_initial_thread_group(CHECK);
3272 Universe::set_main_thread_group(thread_group());
3273 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3274 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3275 main_thread->set_threadObj(thread_object);
3276 // Set thread status to running since main thread has
3277 // been started and running.
3278 java_lang_Thread::set_thread_status(thread_object,
3279 java_lang_Thread::RUNNABLE);
3280
3281 // The VM creates & returns objects of this class. Make sure it's initialized.
3282 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3283
3284 // The VM preresolves methods to these classes. Make sure that they get initialized
3285 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3286 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3287 call_initializeSystemClass(CHECK);
3288
3289 // get the Java runtime name after java.lang.System is initialized
3290 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3291 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3292
3293 // an instance of OutOfMemory exception has been allocated earlier
3294 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3295 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3296 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3297 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3298 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3299 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3300 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3301 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3302 }
3303
3304 void Threads::initialize_jsr292_core_classes(TRAPS) {
3305 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3306 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3307 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3308 }
3309
3310 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3311 extern void JDK_Version_init();
3312
3313 // Check version
3314 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3315
3316 // Initialize the output stream module
3317 ostream_init();
3318
3319 // Process java launcher properties.
3320 Arguments::process_sun_java_launcher_properties(args);
3321
3322 // Initialize the os module before using TLS
3323 os::init();
3324
3325 // Initialize system properties.
3326 Arguments::init_system_properties();
3327
3328 // So that JDK version can be used as a discriminator when parsing arguments
3329 JDK_Version_init();
3330
3331 // Update/Initialize System properties after JDK version number is known
3332 Arguments::init_version_specific_system_properties();
3333
3334 // Parse arguments
3335 jint parse_result = Arguments::parse(args);
3336 if (parse_result != JNI_OK) return parse_result;
3337
3338 os::init_before_ergo();
3339
3340 jint ergo_result = Arguments::apply_ergo();
3341 if (ergo_result != JNI_OK) return ergo_result;
3342
3343 if (PauseAtStartup) {
3344 os::pause();
3345 }
3346
3347 HOTSPOT_VM_INIT_BEGIN();
3348
3349 // Record VM creation timing statistics
3350 TraceVmCreationTime create_vm_timer;
3351 create_vm_timer.start();
3352
3353 // Timing (must come after argument parsing)
3354 TraceTime timer("Create VM", TraceStartupTime);
3355
3356 // Initialize the os module after parsing the args
3357 jint os_init_2_result = os::init_2();
3358 if (os_init_2_result != JNI_OK) return os_init_2_result;
3359
3360 jint adjust_after_os_result = Arguments::adjust_after_os();
3361 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3362
3363 // initialize TLS
3364 ThreadLocalStorage::init();
3365
3366 // Initialize output stream logging
3367 ostream_init_log();
3368
3369 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3370 // Must be before create_vm_init_agents()
3371 if (Arguments::init_libraries_at_startup()) {
3372 convert_vm_init_libraries_to_agents();
3373 }
3374
3375 // Launch -agentlib/-agentpath and converted -Xrun agents
3376 if (Arguments::init_agents_at_startup()) {
3377 create_vm_init_agents();
3378 }
3379
3380 // Initialize Threads state
3381 _thread_list = NULL;
3382 _number_of_threads = 0;
3383 _number_of_non_daemon_threads = 0;
3384
3385 // Initialize global data structures and create system classes in heap
3386 vm_init_globals();
3387
3388 // Attach the main thread to this os thread
3389 JavaThread* main_thread = new JavaThread();
3390 main_thread->set_thread_state(_thread_in_vm);
3391 // must do this before set_active_handles and initialize_thread_local_storage
3392 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3393 // change the stack size recorded here to one based on the java thread
3394 // stacksize. This adjusted size is what is used to figure the placement
3395 // of the guard pages.
3396 main_thread->record_stack_base_and_size();
3397 main_thread->initialize_thread_local_storage();
3398
3399 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3400
3401 if (!main_thread->set_as_starting_thread()) {
3402 vm_shutdown_during_initialization(
3403 "Failed necessary internal allocation. Out of swap space");
3404 delete main_thread;
3405 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3406 return JNI_ENOMEM;
3407 }
3408
3409 // Enable guard page *after* os::create_main_thread(), otherwise it would
3410 // crash Linux VM, see notes in os_linux.cpp.
3411 main_thread->create_stack_guard_pages();
3412
3413 // Initialize Java-Level synchronization subsystem
3414 ObjectMonitor::Initialize();
3415
3416 // Initialize global modules
3417 jint status = init_globals();
3418 if (status != JNI_OK) {
3419 delete main_thread;
3420 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3421 return status;
3422 }
3423
3424 // Should be done after the heap is fully created
3425 main_thread->cache_global_variables();
3426
3427 HandleMark hm;
3428
3429 { MutexLocker mu(Threads_lock);
3430 Threads::add(main_thread);
3431 }
3432
3433 // Any JVMTI raw monitors entered in onload will transition into
3434 // real raw monitor. VM is setup enough here for raw monitor enter.
3435 JvmtiExport::transition_pending_onload_raw_monitors();
3436
3437 // Create the VMThread
3438 { TraceTime timer("Start VMThread", TraceStartupTime);
3439 VMThread::create();
3440 Thread* vmthread = VMThread::vm_thread();
3441
3442 if (!os::create_thread(vmthread, os::vm_thread)) {
3443 vm_exit_during_initialization("Cannot create VM thread. "
3444 "Out of system resources.");
3445 }
3446
3447 // Wait for the VM thread to become ready, and VMThread::run to initialize
3448 // Monitors can have spurious returns, must always check another state flag
3449 {
3450 MutexLocker ml(Notify_lock);
3451 os::start_thread(vmthread);
3452 while (vmthread->active_handles() == NULL) {
3453 Notify_lock->wait();
3454 }
3455 }
3456 }
3457
3458 assert(Universe::is_fully_initialized(), "not initialized");
3459 if (VerifyDuringStartup) {
3460 // Make sure we're starting with a clean slate.
3461 VM_Verify verify_op;
3462 VMThread::execute(&verify_op);
3463 }
3464
3465 Thread* THREAD = Thread::current();
3466
3467 // At this point, the Universe is initialized, but we have not executed
3468 // any byte code. Now is a good time (the only time) to dump out the
3469 // internal state of the JVM for sharing.
3470 if (DumpSharedSpaces) {
3471 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3472 ShouldNotReachHere();
3473 }
3474
3475 // Always call even when there are not JVMTI environments yet, since environments
3476 // may be attached late and JVMTI must track phases of VM execution
3477 JvmtiExport::enter_start_phase();
3478
3479 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3480 JvmtiExport::post_vm_start();
3481
3482 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3483
3484 // We need this for ClassDataSharing - the initial vm.info property is set
3485 // with the default value of CDS "sharing" which may be reset through
3486 // command line options.
3487 reset_vm_info_property(CHECK_JNI_ERR);
3488
3489 quicken_jni_functions();
3490
3491 // Must be run after init_ft which initializes ft_enabled
3492 if (TRACE_INITIALIZE() != JNI_OK) {
3493 vm_exit_during_initialization("Failed to initialize tracing backend");
3494 }
3495
3496 // Set flag that basic initialization has completed. Used by exceptions and various
3497 // debug stuff, that does not work until all basic classes have been initialized.
3498 set_init_completed();
3499
3500 Metaspace::post_initialize();
3501
3502 HOTSPOT_VM_INIT_END();
3503
3504 // record VM initialization completion time
3505 #if INCLUDE_MANAGEMENT
3506 Management::record_vm_init_completed();
3507 #endif // INCLUDE_MANAGEMENT
3508
3509 // Compute system loader. Note that this has to occur after set_init_completed, since
3510 // valid exceptions may be thrown in the process.
3511 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3512 // set_init_completed has just been called, causing exceptions not to be shortcut
3513 // anymore. We call vm_exit_during_initialization directly instead.
3514 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3515
3516 #if INCLUDE_ALL_GCS
3517 // Support for ConcurrentMarkSweep. This should be cleaned up
3518 // and better encapsulated. The ugly nested if test would go away
3519 // once things are properly refactored. XXX YSR
3520 if (UseConcMarkSweepGC || UseG1GC) {
3521 if (UseConcMarkSweepGC) {
3522 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3523 } else {
3524 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3525 }
3526 }
3527 #endif // INCLUDE_ALL_GCS
3528
3529 // Always call even when there are not JVMTI environments yet, since environments
3530 // may be attached late and JVMTI must track phases of VM execution
3531 JvmtiExport::enter_live_phase();
3532
3533 // Signal Dispatcher needs to be started before VMInit event is posted
3534 os::signal_init();
3535
3536 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3537 if (!DisableAttachMechanism) {
3538 AttachListener::vm_start();
3539 if (StartAttachListener || AttachListener::init_at_startup()) {
3540 AttachListener::init();
3541 }
3542 }
3543
3544 // Launch -Xrun agents
3545 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3546 // back-end can launch with -Xdebug -Xrunjdwp.
3547 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3548 create_vm_init_libraries();
3549 }
3550
3551 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3552 JvmtiExport::post_vm_initialized();
3553
3554 if (TRACE_START() != JNI_OK) {
3555 vm_exit_during_initialization("Failed to start tracing backend.");
3556 }
3557
3558 if (CleanChunkPoolAsync) {
3559 Chunk::start_chunk_pool_cleaner_task();
3560 }
3561
3562 // initialize compiler(s)
3563 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3564 CompileBroker::compilation_init();
3565 #endif
3566
3567 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3568 // It is done after compilers are initialized, because otherwise compilations of
3569 // signature polymorphic MH intrinsics can be missed
3570 // (see SystemDictionary::find_method_handle_intrinsic).
3571 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3572
3573 #if INCLUDE_MANAGEMENT
3574 Management::initialize(THREAD);
3575
3576 if (HAS_PENDING_EXCEPTION) {
3577 // management agent fails to start possibly due to
3578 // configuration problem and is responsible for printing
3579 // stack trace if appropriate. Simply exit VM.
3580 vm_exit(1);
3581 }
3582 #endif // INCLUDE_MANAGEMENT
3583
3584 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3585 if (MemProfiling) MemProfiler::engage();
3586 StatSampler::engage();
3587 if (CheckJNICalls) JniPeriodicChecker::engage();
3588
3589 BiasedLocking::init();
3590
3591 #if INCLUDE_RTM_OPT
3592 RTMLockingCounters::init();
3593 #endif
3594
3595 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3596 call_postVMInitHook(THREAD);
3597 // The Java side of PostVMInitHook.run must deal with all
3598 // exceptions and provide means of diagnosis.
3599 if (HAS_PENDING_EXCEPTION) {
3600 CLEAR_PENDING_EXCEPTION;
3601 }
3602 }
3603
3604 {
3605 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3606 // Make sure the watcher thread can be started by WatcherThread::start()
3607 // or by dynamic enrollment.
3608 WatcherThread::make_startable();
3609 // Start up the WatcherThread if there are any periodic tasks
3610 // NOTE: All PeriodicTasks should be registered by now. If they
3611 // aren't, late joiners might appear to start slowly (we might
3612 // take a while to process their first tick).
3613 if (PeriodicTask::num_tasks() > 0) {
3614 WatcherThread::start();
3615 }
3616 }
3617
3618 create_vm_timer.end();
3619 #ifdef ASSERT
3620 _vm_complete = true;
3621 #endif
3622 return JNI_OK;
3623 }
3624
3625 // type for the Agent_OnLoad and JVM_OnLoad entry points
3626 extern "C" {
3627 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3628 }
3629 // Find a command line agent library and return its entry point for
3630 // -agentlib: -agentpath: -Xrun
3631 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3632 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3633 const char *on_load_symbols[],
3634 size_t num_symbol_entries) {
3635 OnLoadEntry_t on_load_entry = NULL;
3636 void *library = NULL;
3637
3638 if (!agent->valid()) {
3639 char buffer[JVM_MAXPATHLEN];
3640 char ebuf[1024] = "";
3641 const char *name = agent->name();
3642 const char *msg = "Could not find agent library ";
3643
3644 // First check to see if agent is statically linked into executable
3645 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3646 library = agent->os_lib();
3647 } else if (agent->is_absolute_path()) {
3648 library = os::dll_load(name, ebuf, sizeof ebuf);
3649 if (library == NULL) {
3650 const char *sub_msg = " in absolute path, with error: ";
3651 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3652 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3653 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3654 // If we can't find the agent, exit.
3655 vm_exit_during_initialization(buf, NULL);
3656 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3657 }
3658 } else {
3659 // Try to load the agent from the standard dll directory
3660 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3661 name)) {
3662 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3663 }
3664 if (library == NULL) { // Try the local directory
3665 char ns[1] = {0};
3666 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3667 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3668 }
3669 if (library == NULL) {
3670 const char *sub_msg = " on the library path, with error: ";
3671 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3672 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3673 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3674 // If we can't find the agent, exit.
3675 vm_exit_during_initialization(buf, NULL);
3676 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3677 }
3678 }
3679 }
3680 agent->set_os_lib(library);
3681 agent->set_valid();
3682 }
3683
3684 // Find the OnLoad function.
3685 on_load_entry =
3686 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3687 false,
3688 on_load_symbols,
3689 num_symbol_entries));
3690 return on_load_entry;
3691 }
3692
3693 // Find the JVM_OnLoad entry point
3694 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3695 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3696 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3697 }
3698
3699 // Find the Agent_OnLoad entry point
3700 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3701 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3702 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3703 }
3704
3705 // For backwards compatibility with -Xrun
3706 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3707 // treated like -agentpath:
3708 // Must be called before agent libraries are created
3709 void Threads::convert_vm_init_libraries_to_agents() {
3710 AgentLibrary* agent;
3711 AgentLibrary* next;
3712
3713 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3714 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3715 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3716
3717 // If there is an JVM_OnLoad function it will get called later,
3718 // otherwise see if there is an Agent_OnLoad
3719 if (on_load_entry == NULL) {
3720 on_load_entry = lookup_agent_on_load(agent);
3721 if (on_load_entry != NULL) {
3722 // switch it to the agent list -- so that Agent_OnLoad will be called,
3723 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3724 Arguments::convert_library_to_agent(agent);
3725 } else {
3726 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3727 }
3728 }
3729 }
3730 }
3731
3732 // Create agents for -agentlib: -agentpath: and converted -Xrun
3733 // Invokes Agent_OnLoad
3734 // Called very early -- before JavaThreads exist
3735 void Threads::create_vm_init_agents() {
3736 extern struct JavaVM_ main_vm;
3737 AgentLibrary* agent;
3738
3739 JvmtiExport::enter_onload_phase();
3740
3741 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3742 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3743
3744 if (on_load_entry != NULL) {
3745 // Invoke the Agent_OnLoad function
3746 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3747 if (err != JNI_OK) {
3748 vm_exit_during_initialization("agent library failed to init", agent->name());
3749 }
3750 } else {
3751 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3752 }
3753 }
3754 JvmtiExport::enter_primordial_phase();
3755 }
3756
3757 extern "C" {
3758 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3759 }
3760
3761 void Threads::shutdown_vm_agents() {
3762 // Send any Agent_OnUnload notifications
3763 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3764 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3765 extern struct JavaVM_ main_vm;
3766 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3767
3768 // Find the Agent_OnUnload function.
3769 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3770 os::find_agent_function(agent,
3771 false,
3772 on_unload_symbols,
3773 num_symbol_entries));
3774
3775 // Invoke the Agent_OnUnload function
3776 if (unload_entry != NULL) {
3777 JavaThread* thread = JavaThread::current();
3778 ThreadToNativeFromVM ttn(thread);
3779 HandleMark hm(thread);
3780 (*unload_entry)(&main_vm);
3781 }
3782 }
3783 }
3784
3785 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3786 // Invokes JVM_OnLoad
3787 void Threads::create_vm_init_libraries() {
3788 extern struct JavaVM_ main_vm;
3789 AgentLibrary* agent;
3790
3791 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3792 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3793
3794 if (on_load_entry != NULL) {
3795 // Invoke the JVM_OnLoad function
3796 JavaThread* thread = JavaThread::current();
3797 ThreadToNativeFromVM ttn(thread);
3798 HandleMark hm(thread);
3799 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3800 if (err != JNI_OK) {
3801 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3802 }
3803 } else {
3804 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3805 }
3806 }
3807 }
3808
3809 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3810 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3811
3812 JavaThread* java_thread = NULL;
3813 // Sequential search for now. Need to do better optimization later.
3814 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3815 oop tobj = thread->threadObj();
3816 if (!thread->is_exiting() &&
3817 tobj != NULL &&
3818 java_tid == java_lang_Thread::thread_id(tobj)) {
3819 java_thread = thread;
3820 break;
3821 }
3822 }
3823 return java_thread;
3824 }
3825
3826
3827 // Last thread running calls java.lang.Shutdown.shutdown()
3828 void JavaThread::invoke_shutdown_hooks() {
3829 HandleMark hm(this);
3830
3831 // We could get here with a pending exception, if so clear it now.
3832 if (this->has_pending_exception()) {
3833 this->clear_pending_exception();
3834 }
3835
3836 EXCEPTION_MARK;
3837 Klass* k =
3838 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3839 THREAD);
3840 if (k != NULL) {
3841 // SystemDictionary::resolve_or_null will return null if there was
3842 // an exception. If we cannot load the Shutdown class, just don't
3843 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3844 // and finalizers (if runFinalizersOnExit is set) won't be run.
3845 // Note that if a shutdown hook was registered or runFinalizersOnExit
3846 // was called, the Shutdown class would have already been loaded
3847 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3848 instanceKlassHandle shutdown_klass (THREAD, k);
3849 JavaValue result(T_VOID);
3850 JavaCalls::call_static(&result,
3851 shutdown_klass,
3852 vmSymbols::shutdown_method_name(),
3853 vmSymbols::void_method_signature(),
3854 THREAD);
3855 }
3856 CLEAR_PENDING_EXCEPTION;
3857 }
3858
3859 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3860 // the program falls off the end of main(). Another VM exit path is through
3861 // vm_exit() when the program calls System.exit() to return a value or when
3862 // there is a serious error in VM. The two shutdown paths are not exactly
3863 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3864 // and VM_Exit op at VM level.
3865 //
3866 // Shutdown sequence:
3867 // + Shutdown native memory tracking if it is on
3868 // + Wait until we are the last non-daemon thread to execute
3869 // <-- every thing is still working at this moment -->
3870 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3871 // shutdown hooks, run finalizers if finalization-on-exit
3872 // + Call before_exit(), prepare for VM exit
3873 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3874 // currently the only user of this mechanism is File.deleteOnExit())
3875 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3876 // post thread end and vm death events to JVMTI,
3877 // stop signal thread
3878 // + Call JavaThread::exit(), it will:
3879 // > release JNI handle blocks, remove stack guard pages
3880 // > remove this thread from Threads list
3881 // <-- no more Java code from this thread after this point -->
3882 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3883 // the compiler threads at safepoint
3884 // <-- do not use anything that could get blocked by Safepoint -->
3885 // + Disable tracing at JNI/JVM barriers
3886 // + Set _vm_exited flag for threads that are still running native code
3887 // + Delete this thread
3888 // + Call exit_globals()
3889 // > deletes tty
3890 // > deletes PerfMemory resources
3891 // + Return to caller
3892
3893 bool Threads::destroy_vm() {
3894 JavaThread* thread = JavaThread::current();
3895
3896 #ifdef ASSERT
3897 _vm_complete = false;
3898 #endif
3899 // Wait until we are the last non-daemon thread to execute
3900 { MutexLocker nu(Threads_lock);
3901 while (Threads::number_of_non_daemon_threads() > 1)
3902 // This wait should make safepoint checks, wait without a timeout,
3903 // and wait as a suspend-equivalent condition.
3904 //
3905 // Note: If the FlatProfiler is running and this thread is waiting
3906 // for another non-daemon thread to finish, then the FlatProfiler
3907 // is waiting for the external suspend request on this thread to
3908 // complete. wait_for_ext_suspend_completion() will eventually
3909 // timeout, but that takes time. Making this wait a suspend-
3910 // equivalent condition solves that timeout problem.
3911 //
3912 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3913 Mutex::_as_suspend_equivalent_flag);
3914 }
3915
3916 // Hang forever on exit if we are reporting an error.
3917 if (ShowMessageBoxOnError && is_error_reported()) {
3918 os::infinite_sleep();
3919 }
3920 os::wait_for_keypress_at_exit();
3921
3922 // run Java level shutdown hooks
3923 thread->invoke_shutdown_hooks();
3924
3925 before_exit(thread);
3926
3927 thread->exit(true);
3928
3929 // Stop VM thread.
3930 {
3931 // 4945125 The vm thread comes to a safepoint during exit.
3932 // GC vm_operations can get caught at the safepoint, and the
3933 // heap is unparseable if they are caught. Grab the Heap_lock
3934 // to prevent this. The GC vm_operations will not be able to
3935 // queue until after the vm thread is dead. After this point,
3936 // we'll never emerge out of the safepoint before the VM exits.
3937
3938 MutexLocker ml(Heap_lock);
3939
3940 VMThread::wait_for_vm_thread_exit();
3941 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3942 VMThread::destroy();
3943 }
3944
3945 // clean up ideal graph printers
3946 #if defined(COMPILER2) && !defined(PRODUCT)
3947 IdealGraphPrinter::clean_up();
3948 #endif
3949
3950 // Now, all Java threads are gone except daemon threads. Daemon threads
3951 // running Java code or in VM are stopped by the Safepoint. However,
3952 // daemon threads executing native code are still running. But they
3953 // will be stopped at native=>Java/VM barriers. Note that we can't
3954 // simply kill or suspend them, as it is inherently deadlock-prone.
3955
3956 #ifndef PRODUCT
3957 // disable function tracing at JNI/JVM barriers
3958 TraceJNICalls = false;
3959 TraceJVMCalls = false;
3960 TraceRuntimeCalls = false;
3961 #endif
3962
3963 VM_Exit::set_vm_exited();
3964
3965 notify_vm_shutdown();
3966
3967 delete thread;
3968
3969 // exit_globals() will delete tty
3970 exit_globals();
3971
3972 return true;
3973 }
3974
3975
3976 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3977 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3978 return is_supported_jni_version(version);
3979 }
3980
3981
3982 jboolean Threads::is_supported_jni_version(jint version) {
3983 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3984 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3985 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3986 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3987 return JNI_FALSE;
3988 }
3989
3990
3991 void Threads::add(JavaThread* p, bool force_daemon) {
3992 // The threads lock must be owned at this point
3993 assert_locked_or_safepoint(Threads_lock);
3994
3995 // See the comment for this method in thread.hpp for its purpose and
3996 // why it is called here.
3997 p->initialize_queues();
3998 p->set_next(_thread_list);
3999 _thread_list = p;
4000 _number_of_threads++;
4001 oop threadObj = p->threadObj();
4002 bool daemon = true;
4003 // Bootstrapping problem: threadObj can be null for initial
4004 // JavaThread (or for threads attached via JNI)
4005 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4006 _number_of_non_daemon_threads++;
4007 daemon = false;
4008 }
4009
4010 ThreadService::add_thread(p, daemon);
4011
4012 // Possible GC point.
4013 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4014 }
4015
4016 void Threads::remove(JavaThread* p) {
4017 // Extra scope needed for Thread_lock, so we can check
4018 // that we do not remove thread without safepoint code notice
4019 { MutexLocker ml(Threads_lock);
4020
4021 assert(includes(p), "p must be present");
4022
4023 JavaThread* current = _thread_list;
4024 JavaThread* prev = NULL;
4025
4026 while (current != p) {
4027 prev = current;
4028 current = current->next();
4029 }
4030
4031 if (prev) {
4032 prev->set_next(current->next());
4033 } else {
4034 _thread_list = p->next();
4035 }
4036 _number_of_threads--;
4037 oop threadObj = p->threadObj();
4038 bool daemon = true;
4039 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4040 _number_of_non_daemon_threads--;
4041 daemon = false;
4042
4043 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4044 // on destroy_vm will wake up.
4045 if (number_of_non_daemon_threads() == 1) {
4046 Threads_lock->notify_all();
4047 }
4048 }
4049 ThreadService::remove_thread(p, daemon);
4050
4051 // Make sure that safepoint code disregard this thread. This is needed since
4052 // the thread might mess around with locks after this point. This can cause it
4053 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4054 // of this thread since it is removed from the queue.
4055 p->set_terminated_value();
4056 } // unlock Threads_lock
4057
4058 // Since Events::log uses a lock, we grab it outside the Threads_lock
4059 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4060 }
4061
4062 // Threads_lock must be held when this is called (or must be called during a safepoint)
4063 bool Threads::includes(JavaThread* p) {
4064 assert(Threads_lock->is_locked(), "sanity check");
4065 ALL_JAVA_THREADS(q) {
4066 if (q == p) {
4067 return true;
4068 }
4069 }
4070 return false;
4071 }
4072
4073 // Operations on the Threads list for GC. These are not explicitly locked,
4074 // but the garbage collector must provide a safe context for them to run.
4075 // In particular, these things should never be called when the Threads_lock
4076 // is held by some other thread. (Note: the Safepoint abstraction also
4077 // uses the Threads_lock to guarantee this property. It also makes sure that
4078 // all threads gets blocked when exiting or starting).
4079
4080 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4081 ALL_JAVA_THREADS(p) {
4082 p->oops_do(f, cld_f, cf);
4083 }
4084 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4085 }
4086
4087 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4088 // Introduce a mechanism allowing parallel threads to claim threads as
4089 // root groups. Overhead should be small enough to use all the time,
4090 // even in sequential code.
4091 SharedHeap* sh = SharedHeap::heap();
4092 // Cannot yet substitute active_workers for n_par_threads
4093 // because of G1CollectedHeap::verify() use of
4094 // SharedHeap::process_roots(). n_par_threads == 0 will
4095 // turn off parallelism in process_roots while active_workers
4096 // is being used for parallelism elsewhere.
4097 bool is_par = sh->n_par_threads() > 0;
4098 assert(!is_par ||
4099 (SharedHeap::heap()->n_par_threads() ==
4100 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4101 int cp = SharedHeap::heap()->strong_roots_parity();
4102 ALL_JAVA_THREADS(p) {
4103 if (p->claim_oops_do(is_par, cp)) {
4104 p->oops_do(f, cld_f, cf);
4105 }
4106 }
4107 VMThread* vmt = VMThread::vm_thread();
4108 if (vmt->claim_oops_do(is_par, cp)) {
4109 vmt->oops_do(f, cld_f, cf);
4110 }
4111 }
4112
4113 #if INCLUDE_ALL_GCS
4114 // Used by ParallelScavenge
4115 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4116 ALL_JAVA_THREADS(p) {
4117 q->enqueue(new ThreadRootsTask(p));
4118 }
4119 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4120 }
4121
4122 // Used by Parallel Old
4123 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4124 ALL_JAVA_THREADS(p) {
4125 q->enqueue(new ThreadRootsMarkingTask(p));
4126 }
4127 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4128 }
4129 #endif // INCLUDE_ALL_GCS
4130
4131 void Threads::nmethods_do(CodeBlobClosure* cf) {
4132 ALL_JAVA_THREADS(p) {
4133 p->nmethods_do(cf);
4134 }
4135 VMThread::vm_thread()->nmethods_do(cf);
4136 }
4137
4138 void Threads::metadata_do(void f(Metadata*)) {
4139 ALL_JAVA_THREADS(p) {
4140 p->metadata_do(f);
4141 }
4142 }
4143
4144 void Threads::deoptimized_wrt_marked_nmethods() {
4145 ALL_JAVA_THREADS(p) {
4146 p->deoptimized_wrt_marked_nmethods();
4147 }
4148 }
4149
4150
4151 // Get count Java threads that are waiting to enter the specified monitor.
4152 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4153 address monitor,
4154 bool doLock) {
4155 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4156 "must grab Threads_lock or be at safepoint");
4157 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4158
4159 int i = 0;
4160 {
4161 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4162 ALL_JAVA_THREADS(p) {
4163 if (p->is_Compiler_thread()) continue;
4164
4165 address pending = (address)p->current_pending_monitor();
4166 if (pending == monitor) { // found a match
4167 if (i < count) result->append(p); // save the first count matches
4168 i++;
4169 }
4170 }
4171 }
4172 return result;
4173 }
4174
4175
4176 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4177 bool doLock) {
4178 assert(doLock ||
4179 Threads_lock->owned_by_self() ||
4180 SafepointSynchronize::is_at_safepoint(),
4181 "must grab Threads_lock or be at safepoint");
4182
4183 // NULL owner means not locked so we can skip the search
4184 if (owner == NULL) return NULL;
4185
4186 {
4187 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4188 ALL_JAVA_THREADS(p) {
4189 // first, see if owner is the address of a Java thread
4190 if (owner == (address)p) return p;
4191 }
4192 }
4193 // Cannot assert on lack of success here since this function may be
4194 // used by code that is trying to report useful problem information
4195 // like deadlock detection.
4196 if (UseHeavyMonitors) return NULL;
4197
4198 // If we didn't find a matching Java thread and we didn't force use of
4199 // heavyweight monitors, then the owner is the stack address of the
4200 // Lock Word in the owning Java thread's stack.
4201 //
4202 JavaThread* the_owner = NULL;
4203 {
4204 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4205 ALL_JAVA_THREADS(q) {
4206 if (q->is_lock_owned(owner)) {
4207 the_owner = q;
4208 break;
4209 }
4210 }
4211 }
4212 // cannot assert on lack of success here; see above comment
4213 return the_owner;
4214 }
4215
4216 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4217 void Threads::print_on(outputStream* st, bool print_stacks,
4218 bool internal_format, bool print_concurrent_locks) {
4219 char buf[32];
4220 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4221
4222 st->print_cr("Full thread dump %s (%s %s):",
4223 Abstract_VM_Version::vm_name(),
4224 Abstract_VM_Version::vm_release(),
4225 Abstract_VM_Version::vm_info_string());
4226 st->cr();
4227
4228 #if INCLUDE_ALL_GCS
4229 // Dump concurrent locks
4230 ConcurrentLocksDump concurrent_locks;
4231 if (print_concurrent_locks) {
4232 concurrent_locks.dump_at_safepoint();
4233 }
4234 #endif // INCLUDE_ALL_GCS
4235
4236 ALL_JAVA_THREADS(p) {
4237 ResourceMark rm;
4238 p->print_on(st);
4239 if (print_stacks) {
4240 if (internal_format) {
4241 p->trace_stack();
4242 } else {
4243 p->print_stack_on(st);
4244 }
4245 }
4246 st->cr();
4247 #if INCLUDE_ALL_GCS
4248 if (print_concurrent_locks) {
4249 concurrent_locks.print_locks_on(p, st);
4250 }
4251 #endif // INCLUDE_ALL_GCS
4252 }
4253
4254 VMThread::vm_thread()->print_on(st);
4255 st->cr();
4256 Universe::heap()->print_gc_threads_on(st);
4257 WatcherThread* wt = WatcherThread::watcher_thread();
4258 if (wt != NULL) {
4259 wt->print_on(st);
4260 st->cr();
4261 }
4262 CompileBroker::print_compiler_threads_on(st);
4263 st->flush();
4264 }
4265
4266 // Threads::print_on_error() is called by fatal error handler. It's possible
4267 // that VM is not at safepoint and/or current thread is inside signal handler.
4268 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4269 // memory (even in resource area), it might deadlock the error handler.
4270 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4271 int buflen) {
4272 bool found_current = false;
4273 st->print_cr("Java Threads: ( => current thread )");
4274 ALL_JAVA_THREADS(thread) {
4275 bool is_current = (current == thread);
4276 found_current = found_current || is_current;
4277
4278 st->print("%s", is_current ? "=>" : " ");
4279
4280 st->print(PTR_FORMAT, thread);
4281 st->print(" ");
4282 thread->print_on_error(st, buf, buflen);
4283 st->cr();
4284 }
4285 st->cr();
4286
4287 st->print_cr("Other Threads:");
4288 if (VMThread::vm_thread()) {
4289 bool is_current = (current == VMThread::vm_thread());
4290 found_current = found_current || is_current;
4291 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4292
4293 st->print(PTR_FORMAT, VMThread::vm_thread());
4294 st->print(" ");
4295 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4296 st->cr();
4297 }
4298 WatcherThread* wt = WatcherThread::watcher_thread();
4299 if (wt != NULL) {
4300 bool is_current = (current == wt);
4301 found_current = found_current || is_current;
4302 st->print("%s", is_current ? "=>" : " ");
4303
4304 st->print(PTR_FORMAT, wt);
4305 st->print(" ");
4306 wt->print_on_error(st, buf, buflen);
4307 st->cr();
4308 }
4309 if (!found_current) {
4310 st->cr();
4311 st->print("=>" PTR_FORMAT " (exited) ", current);
4312 current->print_on_error(st, buf, buflen);
4313 st->cr();
4314 }
4315 }
4316
4317 // Internal SpinLock and Mutex
4318 // Based on ParkEvent
4319
4320 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4321 //
4322 // We employ SpinLocks _only for low-contention, fixed-length
4323 // short-duration critical sections where we're concerned
4324 // about native mutex_t or HotSpot Mutex:: latency.
4325 // The mux construct provides a spin-then-block mutual exclusion
4326 // mechanism.
4327 //
4328 // Testing has shown that contention on the ListLock guarding gFreeList
4329 // is common. If we implement ListLock as a simple SpinLock it's common
4330 // for the JVM to devolve to yielding with little progress. This is true
4331 // despite the fact that the critical sections protected by ListLock are
4332 // extremely short.
4333 //
4334 // TODO-FIXME: ListLock should be of type SpinLock.
4335 // We should make this a 1st-class type, integrated into the lock
4336 // hierarchy as leaf-locks. Critically, the SpinLock structure
4337 // should have sufficient padding to avoid false-sharing and excessive
4338 // cache-coherency traffic.
4339
4340
4341 typedef volatile int SpinLockT;
4342
4343 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4344 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4345 return; // normal fast-path return
4346 }
4347
4348 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4349 TEVENT(SpinAcquire - ctx);
4350 int ctr = 0;
4351 int Yields = 0;
4352 for (;;) {
4353 while (*adr != 0) {
4354 ++ctr;
4355 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4356 if (Yields > 5) {
4357 os::naked_short_sleep(1);
4358 } else {
4359 os::naked_yield();
4360 ++Yields;
4361 }
4362 } else {
4363 SpinPause();
4364 }
4365 }
4366 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4367 }
4368 }
4369
4370 void Thread::SpinRelease(volatile int * adr) {
4371 assert(*adr != 0, "invariant");
4372 OrderAccess::fence(); // guarantee at least release consistency.
4373 // Roach-motel semantics.
4374 // It's safe if subsequent LDs and STs float "up" into the critical section,
4375 // but prior LDs and STs within the critical section can't be allowed
4376 // to reorder or float past the ST that releases the lock.
4377 // Loads and stores in the critical section - which appear in program
4378 // order before the store that releases the lock - must also appear
4379 // before the store that releases the lock in memory visibility order.
4380 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4381 // the ST of 0 into the lock-word which releases the lock, so fence
4382 // more than covers this on all platforms.
4383 *adr = 0;
4384 }
4385
4386 // muxAcquire and muxRelease:
4387 //
4388 // * muxAcquire and muxRelease support a single-word lock-word construct.
4389 // The LSB of the word is set IFF the lock is held.
4390 // The remainder of the word points to the head of a singly-linked list
4391 // of threads blocked on the lock.
4392 //
4393 // * The current implementation of muxAcquire-muxRelease uses its own
4394 // dedicated Thread._MuxEvent instance. If we're interested in
4395 // minimizing the peak number of extant ParkEvent instances then
4396 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4397 // as certain invariants were satisfied. Specifically, care would need
4398 // to be taken with regards to consuming unpark() "permits".
4399 // A safe rule of thumb is that a thread would never call muxAcquire()
4400 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4401 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4402 // consume an unpark() permit intended for monitorenter, for instance.
4403 // One way around this would be to widen the restricted-range semaphore
4404 // implemented in park(). Another alternative would be to provide
4405 // multiple instances of the PlatformEvent() for each thread. One
4406 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4407 //
4408 // * Usage:
4409 // -- Only as leaf locks
4410 // -- for short-term locking only as muxAcquire does not perform
4411 // thread state transitions.
4412 //
4413 // Alternatives:
4414 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4415 // but with parking or spin-then-park instead of pure spinning.
4416 // * Use Taura-Oyama-Yonenzawa locks.
4417 // * It's possible to construct a 1-0 lock if we encode the lockword as
4418 // (List,LockByte). Acquire will CAS the full lockword while Release
4419 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4420 // acquiring threads use timers (ParkTimed) to detect and recover from
4421 // the stranding window. Thread/Node structures must be aligned on 256-byte
4422 // boundaries by using placement-new.
4423 // * Augment MCS with advisory back-link fields maintained with CAS().
4424 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4425 // The validity of the backlinks must be ratified before we trust the value.
4426 // If the backlinks are invalid the exiting thread must back-track through the
4427 // the forward links, which are always trustworthy.
4428 // * Add a successor indication. The LockWord is currently encoded as
4429 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4430 // to provide the usual futile-wakeup optimization.
4431 // See RTStt for details.
4432 // * Consider schedctl.sc_nopreempt to cover the critical section.
4433 //
4434
4435
4436 typedef volatile intptr_t MutexT; // Mux Lock-word
4437 enum MuxBits { LOCKBIT = 1 };
4438
4439 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4440 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4441 if (w == 0) return;
4442 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4443 return;
4444 }
4445
4446 TEVENT(muxAcquire - Contention);
4447 ParkEvent * const Self = Thread::current()->_MuxEvent;
4448 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4449 for (;;) {
4450 int its = (os::is_MP() ? 100 : 0) + 1;
4451
4452 // Optional spin phase: spin-then-park strategy
4453 while (--its >= 0) {
4454 w = *Lock;
4455 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4456 return;
4457 }
4458 }
4459
4460 Self->reset();
4461 Self->OnList = intptr_t(Lock);
4462 // The following fence() isn't _strictly necessary as the subsequent
4463 // CAS() both serializes execution and ratifies the fetched *Lock value.
4464 OrderAccess::fence();
4465 for (;;) {
4466 w = *Lock;
4467 if ((w & LOCKBIT) == 0) {
4468 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4469 Self->OnList = 0; // hygiene - allows stronger asserts
4470 return;
4471 }
4472 continue; // Interference -- *Lock changed -- Just retry
4473 }
4474 assert(w & LOCKBIT, "invariant");
4475 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4476 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4477 }
4478
4479 while (Self->OnList != 0) {
4480 Self->park();
4481 }
4482 }
4483 }
4484
4485 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4486 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4487 if (w == 0) return;
4488 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4489 return;
4490 }
4491
4492 TEVENT(muxAcquire - Contention);
4493 ParkEvent * ReleaseAfter = NULL;
4494 if (ev == NULL) {
4495 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4496 }
4497 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4498 for (;;) {
4499 guarantee(ev->OnList == 0, "invariant");
4500 int its = (os::is_MP() ? 100 : 0) + 1;
4501
4502 // Optional spin phase: spin-then-park strategy
4503 while (--its >= 0) {
4504 w = *Lock;
4505 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4506 if (ReleaseAfter != NULL) {
4507 ParkEvent::Release(ReleaseAfter);
4508 }
4509 return;
4510 }
4511 }
4512
4513 ev->reset();
4514 ev->OnList = intptr_t(Lock);
4515 // The following fence() isn't _strictly necessary as the subsequent
4516 // CAS() both serializes execution and ratifies the fetched *Lock value.
4517 OrderAccess::fence();
4518 for (;;) {
4519 w = *Lock;
4520 if ((w & LOCKBIT) == 0) {
4521 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4522 ev->OnList = 0;
4523 // We call ::Release while holding the outer lock, thus
4524 // artificially lengthening the critical section.
4525 // Consider deferring the ::Release() until the subsequent unlock(),
4526 // after we've dropped the outer lock.
4527 if (ReleaseAfter != NULL) {
4528 ParkEvent::Release(ReleaseAfter);
4529 }
4530 return;
4531 }
4532 continue; // Interference -- *Lock changed -- Just retry
4533 }
4534 assert(w & LOCKBIT, "invariant");
4535 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4536 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4537 }
4538
4539 while (ev->OnList != 0) {
4540 ev->park();
4541 }
4542 }
4543 }
4544
4545 // Release() must extract a successor from the list and then wake that thread.
4546 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4547 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4548 // Release() would :
4549 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4550 // (B) Extract a successor from the private list "in-hand"
4551 // (C) attempt to CAS() the residual back into *Lock over null.
4552 // If there were any newly arrived threads and the CAS() would fail.
4553 // In that case Release() would detach the RATs, re-merge the list in-hand
4554 // with the RATs and repeat as needed. Alternately, Release() might
4555 // detach and extract a successor, but then pass the residual list to the wakee.
4556 // The wakee would be responsible for reattaching and remerging before it
4557 // competed for the lock.
4558 //
4559 // Both "pop" and DMR are immune from ABA corruption -- there can be
4560 // multiple concurrent pushers, but only one popper or detacher.
4561 // This implementation pops from the head of the list. This is unfair,
4562 // but tends to provide excellent throughput as hot threads remain hot.
4563 // (We wake recently run threads first).
4564 //
4565 // All paths through muxRelease() will execute a CAS.
4566 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4567 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4568 // executed within the critical section are complete and globally visible before the
4569 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4570 void Thread::muxRelease(volatile intptr_t * Lock) {
4571 for (;;) {
4572 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4573 assert(w & LOCKBIT, "invariant");
4574 if (w == LOCKBIT) return;
4575 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4576 assert(List != NULL, "invariant");
4577 assert(List->OnList == intptr_t(Lock), "invariant");
4578 ParkEvent * const nxt = List->ListNext;
4579 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4580
4581 // The following CAS() releases the lock and pops the head element.
4582 // The CAS() also ratifies the previously fetched lock-word value.
4583 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4584 continue;
4585 }
4586 List->OnList = 0;
4587 OrderAccess::fence();
4588 List->unpark();
4589 return;
4590 }
4591 }
4592
4593
4594 void Threads::verify() {
4595 ALL_JAVA_THREADS(p) {
4596 p->verify();
4597 }
4598 VMThread* thread = VMThread::vm_thread();
4599 if (thread != NULL) thread->verify();
4600 }