1 /*
2 * Copyright (c) 1997, 2013, 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/scopeDesc.hpp"
31 #include "compiler/compileBroker.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "interpreter/linkResolver.hpp"
34 #include "interpreter/oopMapCache.hpp"
35 #include "jvmtifiles/jvmtiEnv.hpp"
36 #include "memory/gcLocker.inline.hpp"
37 #include "memory/metaspaceShared.hpp"
38 #include "memory/oopFactory.hpp"
39 #include "memory/universe.inline.hpp"
40 #include "oops/instanceKlass.hpp"
41 #include "oops/objArrayOop.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "oops/symbol.hpp"
44 #include "prims/jvm_misc.hpp"
45 #include "prims/jvmtiExport.hpp"
46 #include "prims/jvmtiThreadState.hpp"
47 #include "prims/privilegedStack.hpp"
48 #include "runtime/aprofiler.hpp"
49 #include "runtime/arguments.hpp"
50 #include "runtime/biasedLocking.hpp"
51 #include "runtime/deoptimization.hpp"
52 #include "runtime/fprofiler.hpp"
53 #include "runtime/frame.inline.hpp"
54 #include "runtime/init.hpp"
55 #include "runtime/interfaceSupport.hpp"
56 #include "runtime/java.hpp"
57 #include "runtime/javaCalls.hpp"
58 #include "runtime/jniPeriodicChecker.hpp"
59 #include "runtime/memprofiler.hpp"
60 #include "runtime/mutexLocker.hpp"
61 #include "runtime/objectMonitor.hpp"
62 #include "runtime/osThread.hpp"
63 #include "runtime/safepoint.hpp"
64 #include "runtime/sharedRuntime.hpp"
65 #include "runtime/statSampler.hpp"
66 #include "runtime/stubRoutines.hpp"
67 #include "runtime/task.hpp"
68 #include "runtime/thread.inline.hpp"
69 #include "runtime/threadCritical.hpp"
70 #include "runtime/threadLocalStorage.hpp"
71 #include "runtime/vframe.hpp"
72 #include "runtime/vframeArray.hpp"
73 #include "runtime/vframe_hp.hpp"
74 #include "runtime/vmThread.hpp"
75 #include "runtime/vm_operations.hpp"
76 #include "services/attachListener.hpp"
77 #include "services/management.hpp"
78 #include "services/memTracker.hpp"
79 #include "services/threadService.hpp"
80 #include "trace/traceEventTypes.hpp"
81 #include "utilities/defaultStream.hpp"
82 #include "utilities/dtrace.hpp"
83 #include "utilities/events.hpp"
84 #include "utilities/preserveException.hpp"
85 #include "utilities/macros.hpp"
86 #ifdef TARGET_OS_FAMILY_linux
87 # include "os_linux.inline.hpp"
88 #endif
89 #ifdef TARGET_OS_FAMILY_solaris
90 # include "os_solaris.inline.hpp"
91 #endif
92 #ifdef TARGET_OS_FAMILY_windows
93 # include "os_windows.inline.hpp"
94 #endif
95 #ifdef TARGET_OS_FAMILY_bsd
96 # include "os_bsd.inline.hpp"
97 #endif
98 #if INCLUDE_ALL_GCS
99 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
100 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
101 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
102 #endif // INCLUDE_ALL_GCS
103 #ifdef COMPILER1
104 #include "c1/c1_Compiler.hpp"
105 #endif
106 #ifdef COMPILER2
107 #include "opto/c2compiler.hpp"
108 #include "opto/idealGraphPrinter.hpp"
109 #endif
110
111 #ifdef DTRACE_ENABLED
112
113 // Only bother with this argument setup if dtrace is available
114
115 #ifndef USDT2
116 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
117 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
118 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
119 intptr_t, intptr_t, bool);
120 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
121 intptr_t, intptr_t, bool);
122
123 #define DTRACE_THREAD_PROBE(probe, javathread) \
124 { \
125 ResourceMark rm(this); \
126 int len = 0; \
127 const char* name = (javathread)->get_thread_name(); \
128 len = strlen(name); \
129 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
130 name, len, \
131 java_lang_Thread::thread_id((javathread)->threadObj()), \
132 (javathread)->osthread()->thread_id(), \
133 java_lang_Thread::is_daemon((javathread)->threadObj())); \
134 }
135
136 #else /* USDT2 */
137
138 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
139 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
140
141 #define DTRACE_THREAD_PROBE(probe, javathread) \
142 { \
143 ResourceMark rm(this); \
144 int len = 0; \
145 const char* name = (javathread)->get_thread_name(); \
146 len = strlen(name); \
147 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
148 (char *) name, len, \
149 java_lang_Thread::thread_id((javathread)->threadObj()), \
150 (uintptr_t) (javathread)->osthread()->thread_id(), \
151 java_lang_Thread::is_daemon((javathread)->threadObj())); \
152 }
153
154 #endif /* USDT2 */
155
156 #else // ndef DTRACE_ENABLED
157
158 #define DTRACE_THREAD_PROBE(probe, javathread)
159
160 #endif // ndef DTRACE_ENABLED
161
162
163 // Class hierarchy
164 // - Thread
165 // - VMThread
166 // - WatcherThread
167 // - ConcurrentMarkSweepThread
168 // - JavaThread
169 // - CompilerThread
170
171 // ======= Thread ========
172 // Support for forcing alignment of thread objects for biased locking
173 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
174 if (UseBiasedLocking) {
175 const int alignment = markOopDesc::biased_lock_alignment;
176 size_t aligned_size = size + (alignment - sizeof(intptr_t));
177 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
178 : AllocateHeap(aligned_size, flags, CURRENT_PC,
179 AllocFailStrategy::RETURN_NULL);
180 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
181 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
182 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
183 "JavaThread alignment code overflowed allocated storage");
184 if (TraceBiasedLocking) {
185 if (aligned_addr != real_malloc_addr)
186 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
187 real_malloc_addr, aligned_addr);
188 }
189 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
190 return aligned_addr;
191 } else {
192 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
193 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
194 }
195 }
196
197 void Thread::operator delete(void* p) {
198 if (UseBiasedLocking) {
199 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
200 FreeHeap(real_malloc_addr, mtThread);
201 } else {
202 FreeHeap(p, mtThread);
203 }
204 }
205
206
207 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
208 // JavaThread
209
210
211 Thread::Thread() {
212 // stack and get_thread
213 set_stack_base(NULL);
214 set_stack_size(0);
215 set_self_raw_id(0);
216 set_lgrp_id(-1);
217
218 // allocated data structures
219 set_osthread(NULL);
220 set_resource_area(new (mtThread)ResourceArea());
221 set_handle_area(new (mtThread) HandleArea(NULL));
222 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(300, true));
223 set_active_handles(NULL);
224 set_free_handle_block(NULL);
225 set_last_handle_mark(NULL);
226
227 // This initial value ==> never claimed.
228 _oops_do_parity = 0;
229
230 // the handle mark links itself to last_handle_mark
231 new HandleMark(this);
232
233 // plain initialization
234 debug_only(_owned_locks = NULL;)
235 debug_only(_allow_allocation_count = 0;)
236 NOT_PRODUCT(_allow_safepoint_count = 0;)
237 NOT_PRODUCT(_skip_gcalot = false;)
238 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
239 _jvmti_env_iteration_count = 0;
240 set_allocated_bytes(0);
241 set_trace_buffer(NULL);
242 _vm_operation_started_count = 0;
243 _vm_operation_completed_count = 0;
244 _current_pending_monitor = NULL;
245 _current_pending_monitor_is_from_java = true;
246 _current_waiting_monitor = NULL;
247 _num_nested_signal = 0;
248 omFreeList = NULL ;
249 omFreeCount = 0 ;
250 omFreeProvision = 32 ;
251 omInUseList = NULL ;
252 omInUseCount = 0 ;
253
254 #ifdef ASSERT
255 _visited_for_critical_count = false;
256 #endif
257
258 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
259 _suspend_flags = 0;
260
261 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
262 _hashStateX = os::random() ;
263 _hashStateY = 842502087 ;
264 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
265 _hashStateW = 273326509 ;
266
267 _OnTrap = 0 ;
268 _schedctl = NULL ;
269 _Stalled = 0 ;
270 _TypeTag = 0x2BAD ;
271
272 // Many of the following fields are effectively final - immutable
273 // Note that nascent threads can't use the Native Monitor-Mutex
274 // construct until the _MutexEvent is initialized ...
275 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
276 // we might instead use a stack of ParkEvents that we could provision on-demand.
277 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
278 // and ::Release()
279 _ParkEvent = ParkEvent::Allocate (this) ;
280 _SleepEvent = ParkEvent::Allocate (this) ;
281 _MutexEvent = ParkEvent::Allocate (this) ;
282 _MuxEvent = ParkEvent::Allocate (this) ;
283
284 #ifdef CHECK_UNHANDLED_OOPS
285 if (CheckUnhandledOops) {
286 _unhandled_oops = new UnhandledOops(this);
287 }
288 #endif // CHECK_UNHANDLED_OOPS
289 #ifdef ASSERT
290 if (UseBiasedLocking) {
291 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
292 assert(this == _real_malloc_address ||
293 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
294 "bug in forced alignment of thread objects");
295 }
296 #endif /* ASSERT */
297 }
298
299 void Thread::initialize_thread_local_storage() {
300 // Note: Make sure this method only calls
301 // non-blocking operations. Otherwise, it might not work
302 // with the thread-startup/safepoint interaction.
303
304 // During Java thread startup, safepoint code should allow this
305 // method to complete because it may need to allocate memory to
306 // store information for the new thread.
307
308 // initialize structure dependent on thread local storage
309 ThreadLocalStorage::set_thread(this);
310 }
311
312 void Thread::record_stack_base_and_size() {
313 set_stack_base(os::current_stack_base());
314 set_stack_size(os::current_stack_size());
315 // CR 7190089: on Solaris, primordial thread's stack is adjusted
316 // in initialize_thread(). Without the adjustment, stack size is
317 // incorrect if stack is set to unlimited (ulimit -s unlimited).
318 // So far, only Solaris has real implementation of initialize_thread().
319 //
320 // set up any platform-specific state.
321 os::initialize_thread(this);
322
323 #if INCLUDE_NMT
324 // record thread's native stack, stack grows downward
325 address stack_low_addr = stack_base() - stack_size();
326 NMTTrackOp op(NMTTrackOp::StackAllocOp, this);
327 op.execute_op((address)stack_low_addr, stack_size(), mtThreadStack, CURRENT_PC);
328 #endif // INCLUDE_NMT
329 }
330
331
332 Thread::~Thread() {
333 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
334 ObjectSynchronizer::omFlush (this) ;
335
336 // stack_base can be NULL if the thread is never started or exited before
337 // record_stack_base_and_size called. Although, we would like to ensure
338 // that all started threads do call record_stack_base_and_size(), there is
339 // not proper way to enforce that.
340 #if INCLUDE_NMT
341 if (_stack_base != NULL) {
342 address low_stack_addr = stack_base() - stack_size();
343 NMTTrackOp op(NMTTrackOp::StackReleaseOp, this);
344 op.execute_op((address)low_stack_addr, stack_size());
345 #ifdef ASSERT
346 set_stack_base(NULL);
347 #endif
348 }
349 #endif // INCLUDE_NMT
350
351 // deallocate data structures
352 delete resource_area();
353 // since the handle marks are using the handle area, we have to deallocated the root
354 // handle mark before deallocating the thread's handle area,
355 assert(last_handle_mark() != NULL, "check we have an element");
356 delete last_handle_mark();
357 assert(last_handle_mark() == NULL, "check we have reached the end");
358
359 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
360 // We NULL out the fields for good hygiene.
361 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
362 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
363 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
364 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
365
366 delete handle_area();
367 delete metadata_handles();
368
369 // osthread() can be NULL, if creation of thread failed.
370 if (osthread() != NULL) os::free_thread(osthread());
371
372 delete _SR_lock;
373
374 // clear thread local storage if the Thread is deleting itself
375 if (this == Thread::current()) {
376 ThreadLocalStorage::set_thread(NULL);
377 } else {
378 // In the case where we're not the current thread, invalidate all the
379 // caches in case some code tries to get the current thread or the
380 // thread that was destroyed, and gets stale information.
381 ThreadLocalStorage::invalidate_all();
382 }
383 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
384 }
385
386 // NOTE: dummy function for assertion purpose.
387 void Thread::run() {
388 ShouldNotReachHere();
389 }
390
391 #ifdef ASSERT
392 // Private method to check for dangling thread pointer
393 void check_for_dangling_thread_pointer(Thread *thread) {
394 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
395 "possibility of dangling Thread pointer");
396 }
397 #endif
398
399
400 #ifndef PRODUCT
401 // Tracing method for basic thread operations
402 void Thread::trace(const char* msg, const Thread* const thread) {
403 if (!TraceThreadEvents) return;
404 ResourceMark rm;
405 ThreadCritical tc;
406 const char *name = "non-Java thread";
407 int prio = -1;
408 if (thread->is_Java_thread()
409 && !thread->is_Compiler_thread()) {
410 // The Threads_lock must be held to get information about
411 // this thread but may not be in some situations when
412 // tracing thread events.
413 bool release_Threads_lock = false;
414 if (!Threads_lock->owned_by_self()) {
415 Threads_lock->lock();
416 release_Threads_lock = true;
417 }
418 JavaThread* jt = (JavaThread *)thread;
419 name = (char *)jt->get_thread_name();
420 oop thread_oop = jt->threadObj();
421 if (thread_oop != NULL) {
422 prio = java_lang_Thread::priority(thread_oop);
423 }
424 if (release_Threads_lock) {
425 Threads_lock->unlock();
426 }
427 }
428 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
429 }
430 #endif
431
432
433 ThreadPriority Thread::get_priority(const Thread* const thread) {
434 trace("get priority", thread);
435 ThreadPriority priority;
436 // Can return an error!
437 (void)os::get_priority(thread, priority);
438 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
439 return priority;
440 }
441
442 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
443 trace("set priority", thread);
444 debug_only(check_for_dangling_thread_pointer(thread);)
445 // Can return an error!
446 (void)os::set_priority(thread, priority);
447 }
448
449
450 void Thread::start(Thread* thread) {
451 trace("start", thread);
452 // Start is different from resume in that its safety is guaranteed by context or
453 // being called from a Java method synchronized on the Thread object.
454 if (!DisableStartThread) {
455 if (thread->is_Java_thread()) {
456 // Initialize the thread state to RUNNABLE before starting this thread.
457 // Can not set it after the thread started because we do not know the
458 // exact thread state at that time. It could be in MONITOR_WAIT or
459 // in SLEEPING or some other state.
460 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
461 java_lang_Thread::RUNNABLE);
462 }
463 os::start_thread(thread);
464 }
465 }
466
467 // Enqueue a VM_Operation to do the job for us - sometime later
468 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
469 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
470 VMThread::execute(vm_stop);
471 }
472
473
474 //
475 // Check if an external suspend request has completed (or has been
476 // cancelled). Returns true if the thread is externally suspended and
477 // false otherwise.
478 //
479 // The bits parameter returns information about the code path through
480 // the routine. Useful for debugging:
481 //
482 // set in is_ext_suspend_completed():
483 // 0x00000001 - routine was entered
484 // 0x00000010 - routine return false at end
485 // 0x00000100 - thread exited (return false)
486 // 0x00000200 - suspend request cancelled (return false)
487 // 0x00000400 - thread suspended (return true)
488 // 0x00001000 - thread is in a suspend equivalent state (return true)
489 // 0x00002000 - thread is native and walkable (return true)
490 // 0x00004000 - thread is native_trans and walkable (needed retry)
491 //
492 // set in wait_for_ext_suspend_completion():
493 // 0x00010000 - routine was entered
494 // 0x00020000 - suspend request cancelled before loop (return false)
495 // 0x00040000 - thread suspended before loop (return true)
496 // 0x00080000 - suspend request cancelled in loop (return false)
497 // 0x00100000 - thread suspended in loop (return true)
498 // 0x00200000 - suspend not completed during retry loop (return false)
499 //
500
501 // Helper class for tracing suspend wait debug bits.
502 //
503 // 0x00000100 indicates that the target thread exited before it could
504 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
505 // 0x00080000 each indicate a cancelled suspend request so they don't
506 // count as wait failures either.
507 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
508
509 class TraceSuspendDebugBits : public StackObj {
510 private:
511 JavaThread * jt;
512 bool is_wait;
513 bool called_by_wait; // meaningful when !is_wait
514 uint32_t * bits;
515
516 public:
517 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
518 uint32_t *_bits) {
519 jt = _jt;
520 is_wait = _is_wait;
521 called_by_wait = _called_by_wait;
522 bits = _bits;
523 }
524
525 ~TraceSuspendDebugBits() {
526 if (!is_wait) {
527 #if 1
528 // By default, don't trace bits for is_ext_suspend_completed() calls.
529 // That trace is very chatty.
530 return;
531 #else
532 if (!called_by_wait) {
533 // If tracing for is_ext_suspend_completed() is enabled, then only
534 // trace calls to it from wait_for_ext_suspend_completion()
535 return;
536 }
537 #endif
538 }
539
540 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
541 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
542 MutexLocker ml(Threads_lock); // needed for get_thread_name()
543 ResourceMark rm;
544
545 tty->print_cr(
546 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
547 jt->get_thread_name(), *bits);
548
549 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
550 }
551 }
552 }
553 };
554 #undef DEBUG_FALSE_BITS
555
556
557 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
558 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
559
560 bool did_trans_retry = false; // only do thread_in_native_trans retry once
561 bool do_trans_retry; // flag to force the retry
562
563 *bits |= 0x00000001;
564
565 do {
566 do_trans_retry = false;
567
568 if (is_exiting()) {
569 // Thread is in the process of exiting. This is always checked
570 // first to reduce the risk of dereferencing a freed JavaThread.
571 *bits |= 0x00000100;
572 return false;
573 }
574
575 if (!is_external_suspend()) {
576 // Suspend request is cancelled. This is always checked before
577 // is_ext_suspended() to reduce the risk of a rogue resume
578 // confusing the thread that made the suspend request.
579 *bits |= 0x00000200;
580 return false;
581 }
582
583 if (is_ext_suspended()) {
584 // thread is suspended
585 *bits |= 0x00000400;
586 return true;
587 }
588
589 // Now that we no longer do hard suspends of threads running
590 // native code, the target thread can be changing thread state
591 // while we are in this routine:
592 //
593 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
594 //
595 // We save a copy of the thread state as observed at this moment
596 // and make our decision about suspend completeness based on the
597 // copy. This closes the race where the thread state is seen as
598 // _thread_in_native_trans in the if-thread_blocked check, but is
599 // seen as _thread_blocked in if-thread_in_native_trans check.
600 JavaThreadState save_state = thread_state();
601
602 if (save_state == _thread_blocked && is_suspend_equivalent()) {
603 // If the thread's state is _thread_blocked and this blocking
604 // condition is known to be equivalent to a suspend, then we can
605 // consider the thread to be externally suspended. This means that
606 // the code that sets _thread_blocked has been modified to do
607 // self-suspension if the blocking condition releases. We also
608 // used to check for CONDVAR_WAIT here, but that is now covered by
609 // the _thread_blocked with self-suspension check.
610 //
611 // Return true since we wouldn't be here unless there was still an
612 // external suspend request.
613 *bits |= 0x00001000;
614 return true;
615 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
616 // Threads running native code will self-suspend on native==>VM/Java
617 // transitions. If its stack is walkable (should always be the case
618 // unless this function is called before the actual java_suspend()
619 // call), then the wait is done.
620 *bits |= 0x00002000;
621 return true;
622 } else if (!called_by_wait && !did_trans_retry &&
623 save_state == _thread_in_native_trans &&
624 frame_anchor()->walkable()) {
625 // The thread is transitioning from thread_in_native to another
626 // thread state. check_safepoint_and_suspend_for_native_trans()
627 // will force the thread to self-suspend. If it hasn't gotten
628 // there yet we may have caught the thread in-between the native
629 // code check above and the self-suspend. Lucky us. If we were
630 // called by wait_for_ext_suspend_completion(), then it
631 // will be doing the retries so we don't have to.
632 //
633 // Since we use the saved thread state in the if-statement above,
634 // there is a chance that the thread has already transitioned to
635 // _thread_blocked by the time we get here. In that case, we will
636 // make a single unnecessary pass through the logic below. This
637 // doesn't hurt anything since we still do the trans retry.
638
639 *bits |= 0x00004000;
640
641 // Once the thread leaves thread_in_native_trans for another
642 // thread state, we break out of this retry loop. We shouldn't
643 // need this flag to prevent us from getting back here, but
644 // sometimes paranoia is good.
645 did_trans_retry = true;
646
647 // We wait for the thread to transition to a more usable state.
648 for (int i = 1; i <= SuspendRetryCount; i++) {
649 // We used to do an "os::yield_all(i)" call here with the intention
650 // that yielding would increase on each retry. However, the parameter
651 // is ignored on Linux which means the yield didn't scale up. Waiting
652 // on the SR_lock below provides a much more predictable scale up for
653 // the delay. It also provides a simple/direct point to check for any
654 // safepoint requests from the VMThread
655
656 // temporarily drops SR_lock while doing wait with safepoint check
657 // (if we're a JavaThread - the WatcherThread can also call this)
658 // and increase delay with each retry
659 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
660
661 // check the actual thread state instead of what we saved above
662 if (thread_state() != _thread_in_native_trans) {
663 // the thread has transitioned to another thread state so
664 // try all the checks (except this one) one more time.
665 do_trans_retry = true;
666 break;
667 }
668 } // end retry loop
669
670
671 }
672 } while (do_trans_retry);
673
674 *bits |= 0x00000010;
675 return false;
676 }
677
678 //
679 // Wait for an external suspend request to complete (or be cancelled).
680 // Returns true if the thread is externally suspended and false otherwise.
681 //
682 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
683 uint32_t *bits) {
684 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
685 false /* !called_by_wait */, bits);
686
687 // local flag copies to minimize SR_lock hold time
688 bool is_suspended;
689 bool pending;
690 uint32_t reset_bits;
691
692 // set a marker so is_ext_suspend_completed() knows we are the caller
693 *bits |= 0x00010000;
694
695 // We use reset_bits to reinitialize the bits value at the top of
696 // each retry loop. This allows the caller to make use of any
697 // unused bits for their own marking purposes.
698 reset_bits = *bits;
699
700 {
701 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
702 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
703 delay, bits);
704 pending = is_external_suspend();
705 }
706 // must release SR_lock to allow suspension to complete
707
708 if (!pending) {
709 // A cancelled suspend request is the only false return from
710 // is_ext_suspend_completed() that keeps us from entering the
711 // retry loop.
712 *bits |= 0x00020000;
713 return false;
714 }
715
716 if (is_suspended) {
717 *bits |= 0x00040000;
718 return true;
719 }
720
721 for (int i = 1; i <= retries; i++) {
722 *bits = reset_bits; // reinit to only track last retry
723
724 // We used to do an "os::yield_all(i)" call here with the intention
725 // that yielding would increase on each retry. However, the parameter
726 // is ignored on Linux which means the yield didn't scale up. Waiting
727 // on the SR_lock below provides a much more predictable scale up for
728 // the delay. It also provides a simple/direct point to check for any
729 // safepoint requests from the VMThread
730
731 {
732 MutexLocker ml(SR_lock());
733 // wait with safepoint check (if we're a JavaThread - the WatcherThread
734 // can also call this) and increase delay with each retry
735 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
736
737 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
738 delay, bits);
739
740 // It is possible for the external suspend request to be cancelled
741 // (by a resume) before the actual suspend operation is completed.
742 // Refresh our local copy to see if we still need to wait.
743 pending = is_external_suspend();
744 }
745
746 if (!pending) {
747 // A cancelled suspend request is the only false return from
748 // is_ext_suspend_completed() that keeps us from staying in the
749 // retry loop.
750 *bits |= 0x00080000;
751 return false;
752 }
753
754 if (is_suspended) {
755 *bits |= 0x00100000;
756 return true;
757 }
758 } // end retry loop
759
760 // thread did not suspend after all our retries
761 *bits |= 0x00200000;
762 return false;
763 }
764
765 #ifndef PRODUCT
766 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
767
768 // This should not need to be atomic as the only way for simultaneous
769 // updates is via interrupts. Even then this should be rare or non-existant
770 // and we don't care that much anyway.
771
772 int index = _jmp_ring_index;
773 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
774 _jmp_ring[index]._target = (intptr_t) target;
775 _jmp_ring[index]._instruction = (intptr_t) instr;
776 _jmp_ring[index]._file = file;
777 _jmp_ring[index]._line = line;
778 }
779 #endif /* PRODUCT */
780
781 // Called by flat profiler
782 // Callers have already called wait_for_ext_suspend_completion
783 // The assertion for that is currently too complex to put here:
784 bool JavaThread::profile_last_Java_frame(frame* _fr) {
785 bool gotframe = false;
786 // self suspension saves needed state.
787 if (has_last_Java_frame() && _anchor.walkable()) {
788 *_fr = pd_last_frame();
789 gotframe = true;
790 }
791 return gotframe;
792 }
793
794 void Thread::interrupt(Thread* thread) {
795 trace("interrupt", thread);
796 debug_only(check_for_dangling_thread_pointer(thread);)
797 os::interrupt(thread);
798 }
799
800 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
801 trace("is_interrupted", thread);
802 debug_only(check_for_dangling_thread_pointer(thread);)
803 // Note: If clear_interrupted==false, this simply fetches and
804 // returns the value of the field osthread()->interrupted().
805 return os::is_interrupted(thread, clear_interrupted);
806 }
807
808
809 // GC Support
810 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
811 jint thread_parity = _oops_do_parity;
812 if (thread_parity != strong_roots_parity) {
813 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
814 if (res == thread_parity) {
815 return true;
816 } else {
817 guarantee(res == strong_roots_parity, "Or else what?");
818 assert(SharedHeap::heap()->workers()->active_workers() > 0,
819 "Should only fail when parallel.");
820 return false;
821 }
822 }
823 assert(SharedHeap::heap()->workers()->active_workers() > 0,
824 "Should only fail when parallel.");
825 return false;
826 }
827
828 void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
829 active_handles()->oops_do(f);
830 // Do oop for ThreadShadow
831 f->do_oop((oop*)&_pending_exception);
832 handle_area()->oops_do(f);
833 }
834
835 void Thread::nmethods_do(CodeBlobClosure* cf) {
836 // no nmethods in a generic thread...
837 }
838
839 void Thread::metadata_do(void f(Metadata*)) {
840 if (metadata_handles() != NULL) {
841 for (int i = 0; i< metadata_handles()->length(); i++) {
842 f(metadata_handles()->at(i));
843 }
844 }
845 }
846
847 void Thread::print_on(outputStream* st) const {
848 // get_priority assumes osthread initialized
849 if (osthread() != NULL) {
850 int os_prio;
851 if (os::get_native_priority(this, &os_prio) == OS_OK) {
852 st->print("os_prio=%d ", os_prio);
853 }
854 st->print("tid=" INTPTR_FORMAT " ", this);
855 osthread()->print_on(st);
856 }
857 debug_only(if (WizardMode) print_owned_locks_on(st);)
858 }
859
860 // Thread::print_on_error() is called by fatal error handler. Don't use
861 // any lock or allocate memory.
862 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
863 if (is_VM_thread()) st->print("VMThread");
864 else if (is_Compiler_thread()) st->print("CompilerThread");
865 else if (is_Java_thread()) st->print("JavaThread");
866 else if (is_GC_task_thread()) st->print("GCTaskThread");
867 else if (is_Watcher_thread()) st->print("WatcherThread");
868 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
869 else st->print("Thread");
870
871 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
872 _stack_base - _stack_size, _stack_base);
873
874 if (osthread()) {
875 st->print(" [id=%d]", osthread()->thread_id());
876 }
877 }
878
879 #ifdef ASSERT
880 void Thread::print_owned_locks_on(outputStream* st) const {
881 Monitor *cur = _owned_locks;
882 if (cur == NULL) {
883 st->print(" (no locks) ");
884 } else {
885 st->print_cr(" Locks owned:");
886 while(cur) {
887 cur->print_on(st);
888 cur = cur->next();
889 }
890 }
891 }
892
893 static int ref_use_count = 0;
894
895 bool Thread::owns_locks_but_compiled_lock() const {
896 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
897 if (cur != Compile_lock) return true;
898 }
899 return false;
900 }
901
902
903 #endif
904
905 #ifndef PRODUCT
906
907 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
908 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
909 // no threads which allow_vm_block's are held
910 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
911 // Check if current thread is allowed to block at a safepoint
912 if (!(_allow_safepoint_count == 0))
913 fatal("Possible safepoint reached by thread that does not allow it");
914 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
915 fatal("LEAF method calling lock?");
916 }
917
918 #ifdef ASSERT
919 if (potential_vm_operation && is_Java_thread()
920 && !Universe::is_bootstrapping()) {
921 // Make sure we do not hold any locks that the VM thread also uses.
922 // This could potentially lead to deadlocks
923 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
924 // Threads_lock is special, since the safepoint synchronization will not start before this is
925 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
926 // since it is used to transfer control between JavaThreads and the VMThread
927 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
928 if ( (cur->allow_vm_block() &&
929 cur != Threads_lock &&
930 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
931 cur != VMOperationRequest_lock &&
932 cur != VMOperationQueue_lock) ||
933 cur->rank() == Mutex::special) {
934 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
935 }
936 }
937 }
938
939 if (GCALotAtAllSafepoints) {
940 // We could enter a safepoint here and thus have a gc
941 InterfaceSupport::check_gc_alot();
942 }
943 #endif
944 }
945 #endif
946
947 bool Thread::is_in_stack(address adr) const {
948 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
949 address end = os::current_stack_pointer();
950 // Allow non Java threads to call this without stack_base
951 if (_stack_base == NULL) return true;
952 if (stack_base() >= adr && adr >= end) return true;
953
954 return false;
955 }
956
957
958 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
959 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
960 // used for compilation in the future. If that change is made, the need for these methods
961 // should be revisited, and they should be removed if possible.
962
963 bool Thread::is_lock_owned(address adr) const {
964 return on_local_stack(adr);
965 }
966
967 bool Thread::set_as_starting_thread() {
968 // NOTE: this must be called inside the main thread.
969 return os::create_main_thread((JavaThread*)this);
970 }
971
972 static void initialize_class(Symbol* class_name, TRAPS) {
973 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
974 InstanceKlass::cast(klass)->initialize(CHECK);
975 }
976
977
978 // Creates the initial ThreadGroup
979 static Handle create_initial_thread_group(TRAPS) {
980 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
981 instanceKlassHandle klass (THREAD, k);
982
983 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
984 {
985 JavaValue result(T_VOID);
986 JavaCalls::call_special(&result,
987 system_instance,
988 klass,
989 vmSymbols::object_initializer_name(),
990 vmSymbols::void_method_signature(),
991 CHECK_NH);
992 }
993 Universe::set_system_thread_group(system_instance());
994
995 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
996 {
997 JavaValue result(T_VOID);
998 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
999 JavaCalls::call_special(&result,
1000 main_instance,
1001 klass,
1002 vmSymbols::object_initializer_name(),
1003 vmSymbols::threadgroup_string_void_signature(),
1004 system_instance,
1005 string,
1006 CHECK_NH);
1007 }
1008 return main_instance;
1009 }
1010
1011 // Creates the initial Thread
1012 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1013 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1014 instanceKlassHandle klass (THREAD, k);
1015 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1016
1017 java_lang_Thread::set_thread(thread_oop(), thread);
1018 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1019 thread->set_threadObj(thread_oop());
1020
1021 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1022
1023 JavaValue result(T_VOID);
1024 JavaCalls::call_special(&result, thread_oop,
1025 klass,
1026 vmSymbols::object_initializer_name(),
1027 vmSymbols::threadgroup_string_void_signature(),
1028 thread_group,
1029 string,
1030 CHECK_NULL);
1031 return thread_oop();
1032 }
1033
1034 static void call_initializeSystemClass(TRAPS) {
1035 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1036 instanceKlassHandle klass (THREAD, k);
1037
1038 JavaValue result(T_VOID);
1039 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1040 vmSymbols::void_method_signature(), CHECK);
1041 }
1042
1043 char java_runtime_name[128] = "";
1044 char java_runtime_version[128] = "";
1045
1046 // extract the JRE name from sun.misc.Version.java_runtime_name
1047 static const char* get_java_runtime_name(TRAPS) {
1048 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1049 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1050 fieldDescriptor fd;
1051 bool found = k != NULL &&
1052 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1053 vmSymbols::string_signature(), &fd);
1054 if (found) {
1055 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1056 if (name_oop == NULL)
1057 return NULL;
1058 const char* name = java_lang_String::as_utf8_string(name_oop,
1059 java_runtime_name,
1060 sizeof(java_runtime_name));
1061 return name;
1062 } else {
1063 return NULL;
1064 }
1065 }
1066
1067 // extract the JRE version from sun.misc.Version.java_runtime_version
1068 static const char* get_java_runtime_version(TRAPS) {
1069 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1070 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1071 fieldDescriptor fd;
1072 bool found = k != NULL &&
1073 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1074 vmSymbols::string_signature(), &fd);
1075 if (found) {
1076 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1077 if (name_oop == NULL)
1078 return NULL;
1079 const char* name = java_lang_String::as_utf8_string(name_oop,
1080 java_runtime_version,
1081 sizeof(java_runtime_version));
1082 return name;
1083 } else {
1084 return NULL;
1085 }
1086 }
1087
1088 // General purpose hook into Java code, run once when the VM is initialized.
1089 // The Java library method itself may be changed independently from the VM.
1090 static void call_postVMInitHook(TRAPS) {
1091 Klass* k = SystemDictionary::PostVMInitHook_klass();
1092 instanceKlassHandle klass (THREAD, k);
1093 if (klass.not_null()) {
1094 JavaValue result(T_VOID);
1095 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1096 vmSymbols::void_method_signature(),
1097 CHECK);
1098 }
1099 }
1100
1101 static void reset_vm_info_property(TRAPS) {
1102 // the vm info string
1103 ResourceMark rm(THREAD);
1104 const char *vm_info = VM_Version::vm_info_string();
1105
1106 // java.lang.System class
1107 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1108 instanceKlassHandle klass (THREAD, k);
1109
1110 // setProperty arguments
1111 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1112 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1113
1114 // return value
1115 JavaValue r(T_OBJECT);
1116
1117 // public static String setProperty(String key, String value);
1118 JavaCalls::call_static(&r,
1119 klass,
1120 vmSymbols::setProperty_name(),
1121 vmSymbols::string_string_string_signature(),
1122 key_str,
1123 value_str,
1124 CHECK);
1125 }
1126
1127
1128 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1129 assert(thread_group.not_null(), "thread group should be specified");
1130 assert(threadObj() == NULL, "should only create Java thread object once");
1131
1132 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1133 instanceKlassHandle klass (THREAD, k);
1134 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1135
1136 java_lang_Thread::set_thread(thread_oop(), this);
1137 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1138 set_threadObj(thread_oop());
1139
1140 JavaValue result(T_VOID);
1141 if (thread_name != NULL) {
1142 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1143 // Thread gets assigned specified name and null target
1144 JavaCalls::call_special(&result,
1145 thread_oop,
1146 klass,
1147 vmSymbols::object_initializer_name(),
1148 vmSymbols::threadgroup_string_void_signature(),
1149 thread_group, // Argument 1
1150 name, // Argument 2
1151 THREAD);
1152 } else {
1153 // Thread gets assigned name "Thread-nnn" and null target
1154 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1155 JavaCalls::call_special(&result,
1156 thread_oop,
1157 klass,
1158 vmSymbols::object_initializer_name(),
1159 vmSymbols::threadgroup_runnable_void_signature(),
1160 thread_group, // Argument 1
1161 Handle(), // Argument 2
1162 THREAD);
1163 }
1164
1165
1166 if (daemon) {
1167 java_lang_Thread::set_daemon(thread_oop());
1168 }
1169
1170 if (HAS_PENDING_EXCEPTION) {
1171 return;
1172 }
1173
1174 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1175 Handle threadObj(this, this->threadObj());
1176
1177 JavaCalls::call_special(&result,
1178 thread_group,
1179 group,
1180 vmSymbols::add_method_name(),
1181 vmSymbols::thread_void_signature(),
1182 threadObj, // Arg 1
1183 THREAD);
1184
1185
1186 }
1187
1188 // NamedThread -- non-JavaThread subclasses with multiple
1189 // uniquely named instances should derive from this.
1190 NamedThread::NamedThread() : Thread() {
1191 _name = NULL;
1192 _processed_thread = NULL;
1193 }
1194
1195 NamedThread::~NamedThread() {
1196 if (_name != NULL) {
1197 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1198 _name = NULL;
1199 }
1200 }
1201
1202 void NamedThread::set_name(const char* format, ...) {
1203 guarantee(_name == NULL, "Only get to set name once.");
1204 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1205 guarantee(_name != NULL, "alloc failure");
1206 va_list ap;
1207 va_start(ap, format);
1208 jio_vsnprintf(_name, max_name_len, format, ap);
1209 va_end(ap);
1210 }
1211
1212 // ======= WatcherThread ========
1213
1214 // The watcher thread exists to simulate timer interrupts. It should
1215 // be replaced by an abstraction over whatever native support for
1216 // timer interrupts exists on the platform.
1217
1218 WatcherThread* WatcherThread::_watcher_thread = NULL;
1219 bool WatcherThread::_startable = false;
1220 volatile bool WatcherThread::_should_terminate = false;
1221
1222 WatcherThread::WatcherThread() : Thread() {
1223 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1224 if (os::create_thread(this, os::watcher_thread)) {
1225 _watcher_thread = this;
1226
1227 // Set the watcher thread to the highest OS priority which should not be
1228 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1229 // is created. The only normal thread using this priority is the reference
1230 // handler thread, which runs for very short intervals only.
1231 // If the VMThread's priority is not lower than the WatcherThread profiling
1232 // will be inaccurate.
1233 os::set_priority(this, MaxPriority);
1234 if (!DisableStartThread) {
1235 os::start_thread(this);
1236 }
1237 }
1238 }
1239
1240 int WatcherThread::sleep() const {
1241 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1242
1243 // remaining will be zero if there are no tasks,
1244 // causing the WatcherThread to sleep until a task is
1245 // enrolled
1246 int remaining = PeriodicTask::time_to_wait();
1247 int time_slept = 0;
1248
1249 // we expect this to timeout - we only ever get unparked when
1250 // we should terminate or when a new task has been enrolled
1251 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1252
1253 jlong time_before_loop = os::javaTimeNanos();
1254
1255 for (;;) {
1256 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1257 jlong now = os::javaTimeNanos();
1258
1259 if (remaining == 0) {
1260 // if we didn't have any tasks we could have waited for a long time
1261 // consider the time_slept zero and reset time_before_loop
1262 time_slept = 0;
1263 time_before_loop = now;
1264 } else {
1265 // need to recalulate since we might have new tasks in _tasks
1266 time_slept = (int) ((now - time_before_loop) / 1000000);
1267 }
1268
1269 // Change to task list or spurious wakeup of some kind
1270 if (timedout || _should_terminate) {
1271 break;
1272 }
1273
1274 remaining = PeriodicTask::time_to_wait();
1275 if (remaining == 0) {
1276 // Last task was just disenrolled so loop around and wait until
1277 // another task gets enrolled
1278 continue;
1279 }
1280
1281 remaining -= time_slept;
1282 if (remaining <= 0)
1283 break;
1284 }
1285
1286 return time_slept;
1287 }
1288
1289 void WatcherThread::run() {
1290 assert(this == watcher_thread(), "just checking");
1291
1292 this->record_stack_base_and_size();
1293 this->initialize_thread_local_storage();
1294 this->set_active_handles(JNIHandleBlock::allocate_block());
1295 while(!_should_terminate) {
1296 assert(watcher_thread() == Thread::current(), "thread consistency check");
1297 assert(watcher_thread() == this, "thread consistency check");
1298
1299 // Calculate how long it'll be until the next PeriodicTask work
1300 // should be done, and sleep that amount of time.
1301 int time_waited = sleep();
1302
1303 if (is_error_reported()) {
1304 // A fatal error has happened, the error handler(VMError::report_and_die)
1305 // should abort JVM after creating an error log file. However in some
1306 // rare cases, the error handler itself might deadlock. Here we try to
1307 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1308 //
1309 // This code is in WatcherThread because WatcherThread wakes up
1310 // periodically so the fatal error handler doesn't need to do anything;
1311 // also because the WatcherThread is less likely to crash than other
1312 // threads.
1313
1314 for (;;) {
1315 if (!ShowMessageBoxOnError
1316 && (OnError == NULL || OnError[0] == '\0')
1317 && Arguments::abort_hook() == NULL) {
1318 os::sleep(this, 2 * 60 * 1000, false);
1319 fdStream err(defaultStream::output_fd());
1320 err.print_raw_cr("# [ timer expired, abort... ]");
1321 // skip atexit/vm_exit/vm_abort hooks
1322 os::die();
1323 }
1324
1325 // Wake up 5 seconds later, the fatal handler may reset OnError or
1326 // ShowMessageBoxOnError when it is ready to abort.
1327 os::sleep(this, 5 * 1000, false);
1328 }
1329 }
1330
1331 PeriodicTask::real_time_tick(time_waited);
1332 }
1333
1334 // Signal that it is terminated
1335 {
1336 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1337 _watcher_thread = NULL;
1338 Terminator_lock->notify();
1339 }
1340
1341 // Thread destructor usually does this..
1342 ThreadLocalStorage::set_thread(NULL);
1343 }
1344
1345 void WatcherThread::start() {
1346 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1347
1348 if (watcher_thread() == NULL && _startable) {
1349 _should_terminate = false;
1350 // Create the single instance of WatcherThread
1351 new WatcherThread();
1352 }
1353 }
1354
1355 void WatcherThread::make_startable() {
1356 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1357 _startable = true;
1358 }
1359
1360 void WatcherThread::stop() {
1361 {
1362 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1363 _should_terminate = true;
1364 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1365
1366 WatcherThread* watcher = watcher_thread();
1367 if (watcher != NULL)
1368 watcher->unpark();
1369 }
1370
1371 // it is ok to take late safepoints here, if needed
1372 MutexLocker mu(Terminator_lock);
1373
1374 while(watcher_thread() != NULL) {
1375 // This wait should make safepoint checks, wait without a timeout,
1376 // and wait as a suspend-equivalent condition.
1377 //
1378 // Note: If the FlatProfiler is running, then this thread is waiting
1379 // for the WatcherThread to terminate and the WatcherThread, via the
1380 // FlatProfiler task, is waiting for the external suspend request on
1381 // this thread to complete. wait_for_ext_suspend_completion() will
1382 // eventually timeout, but that takes time. Making this wait a
1383 // suspend-equivalent condition solves that timeout problem.
1384 //
1385 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1386 Mutex::_as_suspend_equivalent_flag);
1387 }
1388 }
1389
1390 void WatcherThread::unpark() {
1391 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1392 PeriodicTask_lock->notify();
1393 }
1394
1395 void WatcherThread::print_on(outputStream* st) const {
1396 st->print("\"%s\" ", name());
1397 Thread::print_on(st);
1398 st->cr();
1399 }
1400
1401 // ======= JavaThread ========
1402
1403 // A JavaThread is a normal Java thread
1404
1405 void JavaThread::initialize() {
1406 // Initialize fields
1407
1408 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1409 set_claimed_par_id(-1);
1410
1411 set_saved_exception_pc(NULL);
1412 set_threadObj(NULL);
1413 _anchor.clear();
1414 set_entry_point(NULL);
1415 set_jni_functions(jni_functions());
1416 set_callee_target(NULL);
1417 set_vm_result(NULL);
1418 set_vm_result_2(NULL);
1419 set_vframe_array_head(NULL);
1420 set_vframe_array_last(NULL);
1421 set_deferred_locals(NULL);
1422 set_deopt_mark(NULL);
1423 set_deopt_nmethod(NULL);
1424 clear_must_deopt_id();
1425 set_monitor_chunks(NULL);
1426 set_next(NULL);
1427 set_thread_state(_thread_new);
1428 #if INCLUDE_NMT
1429 set_recorder(NULL);
1430 #endif
1431 _terminated = _not_terminated;
1432 _privileged_stack_top = NULL;
1433 _array_for_gc = NULL;
1434 _suspend_equivalent = false;
1435 _in_deopt_handler = 0;
1436 _doing_unsafe_access = false;
1437 _stack_guard_state = stack_guard_unused;
1438 _exception_oop = NULL;
1439 _exception_pc = 0;
1440 _exception_handler_pc = 0;
1441 _is_method_handle_return = 0;
1442 _jvmti_thread_state= NULL;
1443 _should_post_on_exceptions_flag = JNI_FALSE;
1444 _jvmti_get_loaded_classes_closure = NULL;
1445 _interp_only_mode = 0;
1446 _special_runtime_exit_condition = _no_async_condition;
1447 _pending_async_exception = NULL;
1448 _is_compiling = false;
1449 _thread_stat = NULL;
1450 _thread_stat = new ThreadStatistics();
1451 _blocked_on_compilation = false;
1452 _jni_active_critical = 0;
1453 _do_not_unlock_if_synchronized = false;
1454 _cached_monitor_info = NULL;
1455 _parker = Parker::Allocate(this) ;
1456
1457 #ifndef PRODUCT
1458 _jmp_ring_index = 0;
1459 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1460 record_jump(NULL, NULL, NULL, 0);
1461 }
1462 #endif /* PRODUCT */
1463
1464 set_thread_profiler(NULL);
1465 if (FlatProfiler::is_active()) {
1466 // This is where we would decide to either give each thread it's own profiler
1467 // or use one global one from FlatProfiler,
1468 // or up to some count of the number of profiled threads, etc.
1469 ThreadProfiler* pp = new ThreadProfiler();
1470 pp->engage();
1471 set_thread_profiler(pp);
1472 }
1473
1474 // Setup safepoint state info for this thread
1475 ThreadSafepointState::create(this);
1476
1477 debug_only(_java_call_counter = 0);
1478
1479 // JVMTI PopFrame support
1480 _popframe_condition = popframe_inactive;
1481 _popframe_preserved_args = NULL;
1482 _popframe_preserved_args_size = 0;
1483
1484 pd_initialize();
1485 }
1486
1487 #if INCLUDE_ALL_GCS
1488 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1489 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1490 #endif // INCLUDE_ALL_GCS
1491
1492 JavaThread::JavaThread(bool is_attaching_via_jni) :
1493 Thread()
1494 #if INCLUDE_ALL_GCS
1495 , _satb_mark_queue(&_satb_mark_queue_set),
1496 _dirty_card_queue(&_dirty_card_queue_set)
1497 #endif // INCLUDE_ALL_GCS
1498 {
1499 initialize();
1500 if (is_attaching_via_jni) {
1501 _jni_attach_state = _attaching_via_jni;
1502 } else {
1503 _jni_attach_state = _not_attaching_via_jni;
1504 }
1505 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1506 _safepoint_visible = false;
1507 }
1508
1509 bool JavaThread::reguard_stack(address cur_sp) {
1510 if (_stack_guard_state != stack_guard_yellow_disabled) {
1511 return true; // Stack already guarded or guard pages not needed.
1512 }
1513
1514 if (register_stack_overflow()) {
1515 // For those architectures which have separate register and
1516 // memory stacks, we must check the register stack to see if
1517 // it has overflowed.
1518 return false;
1519 }
1520
1521 // Java code never executes within the yellow zone: the latter is only
1522 // there to provoke an exception during stack banging. If java code
1523 // is executing there, either StackShadowPages should be larger, or
1524 // some exception code in c1, c2 or the interpreter isn't unwinding
1525 // when it should.
1526 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1527
1528 enable_stack_yellow_zone();
1529 return true;
1530 }
1531
1532 bool JavaThread::reguard_stack(void) {
1533 return reguard_stack(os::current_stack_pointer());
1534 }
1535
1536
1537 void JavaThread::block_if_vm_exited() {
1538 if (_terminated == _vm_exited) {
1539 // _vm_exited is set at safepoint, and Threads_lock is never released
1540 // we will block here forever
1541 Threads_lock->lock_without_safepoint_check();
1542 ShouldNotReachHere();
1543 }
1544 }
1545
1546
1547 // Remove this ifdef when C1 is ported to the compiler interface.
1548 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1549
1550 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1551 Thread()
1552 #if INCLUDE_ALL_GCS
1553 , _satb_mark_queue(&_satb_mark_queue_set),
1554 _dirty_card_queue(&_dirty_card_queue_set)
1555 #endif // INCLUDE_ALL_GCS
1556 {
1557 if (TraceThreadEvents) {
1558 tty->print_cr("creating thread %p", this);
1559 }
1560 initialize();
1561 _jni_attach_state = _not_attaching_via_jni;
1562 set_entry_point(entry_point);
1563 // Create the native thread itself.
1564 // %note runtime_23
1565 os::ThreadType thr_type = os::java_thread;
1566 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1567 os::java_thread;
1568 os::create_thread(this, thr_type, stack_sz);
1569 _safepoint_visible = false;
1570 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1571 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1572 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1573 // the exception consists of creating the exception object & initializing it, initialization
1574 // will leave the VM via a JavaCall and then all locks must be unlocked).
1575 //
1576 // The thread is still suspended when we reach here. Thread must be explicit started
1577 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1578 // by calling Threads:add. The reason why this is not done here, is because the thread
1579 // object must be fully initialized (take a look at JVM_Start)
1580 }
1581
1582 JavaThread::~JavaThread() {
1583 if (TraceThreadEvents) {
1584 tty->print_cr("terminate thread %p", this);
1585 }
1586
1587 // By now, this thread should already be invisible to safepoint,
1588 // and its per-thread recorder also collected.
1589 assert(!is_safepoint_visible(), "wrong state");
1590 #if INCLUDE_NMT
1591 assert(get_recorder() == NULL, "Already collected");
1592 #endif // INCLUDE_NMT
1593
1594 // JSR166 -- return the parker to the free list
1595 Parker::Release(_parker);
1596 _parker = NULL ;
1597
1598 // Free any remaining previous UnrollBlock
1599 vframeArray* old_array = vframe_array_last();
1600
1601 if (old_array != NULL) {
1602 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1603 old_array->set_unroll_block(NULL);
1604 delete old_info;
1605 delete old_array;
1606 }
1607
1608 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1609 if (deferred != NULL) {
1610 // This can only happen if thread is destroyed before deoptimization occurs.
1611 assert(deferred->length() != 0, "empty array!");
1612 do {
1613 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1614 deferred->remove_at(0);
1615 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1616 delete dlv;
1617 } while (deferred->length() != 0);
1618 delete deferred;
1619 }
1620
1621 // All Java related clean up happens in exit
1622 ThreadSafepointState::destroy(this);
1623 if (_thread_profiler != NULL) delete _thread_profiler;
1624 if (_thread_stat != NULL) delete _thread_stat;
1625 }
1626
1627
1628 // The first routine called by a new Java thread
1629 void JavaThread::run() {
1630 // initialize thread-local alloc buffer related fields
1631 this->initialize_tlab();
1632
1633 // used to test validitity of stack trace backs
1634 this->record_base_of_stack_pointer();
1635
1636 // Record real stack base and size.
1637 this->record_stack_base_and_size();
1638
1639 // Initialize thread local storage; set before calling MutexLocker
1640 this->initialize_thread_local_storage();
1641
1642 this->create_stack_guard_pages();
1643
1644 this->cache_global_variables();
1645
1646 // Thread is now sufficient initialized to be handled by the safepoint code as being
1647 // in the VM. Change thread state from _thread_new to _thread_in_vm
1648 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1649
1650 assert(JavaThread::current() == this, "sanity check");
1651 assert(!Thread::current()->owns_locks(), "sanity check");
1652
1653 DTRACE_THREAD_PROBE(start, this);
1654
1655 // This operation might block. We call that after all safepoint checks for a new thread has
1656 // been completed.
1657 this->set_active_handles(JNIHandleBlock::allocate_block());
1658
1659 if (JvmtiExport::should_post_thread_life()) {
1660 JvmtiExport::post_thread_start(this);
1661 }
1662
1663 EVENT_BEGIN(TraceEventThreadStart, event);
1664 EVENT_COMMIT(event,
1665 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj())));
1666
1667 // We call another function to do the rest so we are sure that the stack addresses used
1668 // from there will be lower than the stack base just computed
1669 thread_main_inner();
1670
1671 // Note, thread is no longer valid at this point!
1672 }
1673
1674
1675 void JavaThread::thread_main_inner() {
1676 assert(JavaThread::current() == this, "sanity check");
1677 assert(this->threadObj() != NULL, "just checking");
1678
1679 // Execute thread entry point unless this thread has a pending exception
1680 // or has been stopped before starting.
1681 // Note: Due to JVM_StopThread we can have pending exceptions already!
1682 if (!this->has_pending_exception() &&
1683 !java_lang_Thread::is_stillborn(this->threadObj())) {
1684 {
1685 ResourceMark rm(this);
1686 this->set_native_thread_name(this->get_thread_name());
1687 }
1688 HandleMark hm(this);
1689 this->entry_point()(this, this);
1690 }
1691
1692 DTRACE_THREAD_PROBE(stop, this);
1693
1694 this->exit(false);
1695 delete this;
1696 }
1697
1698
1699 static void ensure_join(JavaThread* thread) {
1700 // We do not need to grap the Threads_lock, since we are operating on ourself.
1701 Handle threadObj(thread, thread->threadObj());
1702 assert(threadObj.not_null(), "java thread object must exist");
1703 ObjectLocker lock(threadObj, thread);
1704 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1705 thread->clear_pending_exception();
1706 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1707 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1708 // Clear the native thread instance - this makes isAlive return false and allows the join()
1709 // to complete once we've done the notify_all below
1710 java_lang_Thread::set_thread(threadObj(), NULL);
1711 lock.notify_all(thread);
1712 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1713 thread->clear_pending_exception();
1714 }
1715
1716
1717 // For any new cleanup additions, please check to see if they need to be applied to
1718 // cleanup_failed_attach_current_thread as well.
1719 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1720 assert(this == JavaThread::current(), "thread consistency check");
1721
1722 HandleMark hm(this);
1723 Handle uncaught_exception(this, this->pending_exception());
1724 this->clear_pending_exception();
1725 Handle threadObj(this, this->threadObj());
1726 assert(threadObj.not_null(), "Java thread object should be created");
1727
1728 if (get_thread_profiler() != NULL) {
1729 get_thread_profiler()->disengage();
1730 ResourceMark rm;
1731 get_thread_profiler()->print(get_thread_name());
1732 }
1733
1734
1735 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1736 {
1737 EXCEPTION_MARK;
1738
1739 CLEAR_PENDING_EXCEPTION;
1740 }
1741 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1742 // has to be fixed by a runtime query method
1743 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1744 // JSR-166: change call from from ThreadGroup.uncaughtException to
1745 // java.lang.Thread.dispatchUncaughtException
1746 if (uncaught_exception.not_null()) {
1747 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1748 {
1749 EXCEPTION_MARK;
1750 // Check if the method Thread.dispatchUncaughtException() exists. If so
1751 // call it. Otherwise we have an older library without the JSR-166 changes,
1752 // so call ThreadGroup.uncaughtException()
1753 KlassHandle recvrKlass(THREAD, threadObj->klass());
1754 CallInfo callinfo;
1755 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1756 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1757 vmSymbols::dispatchUncaughtException_name(),
1758 vmSymbols::throwable_void_signature(),
1759 KlassHandle(), false, false, THREAD);
1760 CLEAR_PENDING_EXCEPTION;
1761 methodHandle method = callinfo.selected_method();
1762 if (method.not_null()) {
1763 JavaValue result(T_VOID);
1764 JavaCalls::call_virtual(&result,
1765 threadObj, thread_klass,
1766 vmSymbols::dispatchUncaughtException_name(),
1767 vmSymbols::throwable_void_signature(),
1768 uncaught_exception,
1769 THREAD);
1770 } else {
1771 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1772 JavaValue result(T_VOID);
1773 JavaCalls::call_virtual(&result,
1774 group, thread_group,
1775 vmSymbols::uncaughtException_name(),
1776 vmSymbols::thread_throwable_void_signature(),
1777 threadObj, // Arg 1
1778 uncaught_exception, // Arg 2
1779 THREAD);
1780 }
1781 if (HAS_PENDING_EXCEPTION) {
1782 ResourceMark rm(this);
1783 jio_fprintf(defaultStream::error_stream(),
1784 "\nException: %s thrown from the UncaughtExceptionHandler"
1785 " in thread \"%s\"\n",
1786 pending_exception()->klass()->external_name(),
1787 get_thread_name());
1788 CLEAR_PENDING_EXCEPTION;
1789 }
1790 }
1791 }
1792
1793 // Called before the java thread exit since we want to read info
1794 // from java_lang_Thread object
1795 EVENT_BEGIN(TraceEventThreadEnd, event);
1796 EVENT_COMMIT(event,
1797 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj())));
1798
1799 // Call after last event on thread
1800 EVENT_THREAD_EXIT(this);
1801
1802 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1803 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1804 // is deprecated anyhow.
1805 { int count = 3;
1806 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1807 EXCEPTION_MARK;
1808 JavaValue result(T_VOID);
1809 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1810 JavaCalls::call_virtual(&result,
1811 threadObj, thread_klass,
1812 vmSymbols::exit_method_name(),
1813 vmSymbols::void_method_signature(),
1814 THREAD);
1815 CLEAR_PENDING_EXCEPTION;
1816 }
1817 }
1818
1819 // notify JVMTI
1820 if (JvmtiExport::should_post_thread_life()) {
1821 JvmtiExport::post_thread_end(this);
1822 }
1823
1824 // We have notified the agents that we are exiting, before we go on,
1825 // we must check for a pending external suspend request and honor it
1826 // in order to not surprise the thread that made the suspend request.
1827 while (true) {
1828 {
1829 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1830 if (!is_external_suspend()) {
1831 set_terminated(_thread_exiting);
1832 ThreadService::current_thread_exiting(this);
1833 break;
1834 }
1835 // Implied else:
1836 // Things get a little tricky here. We have a pending external
1837 // suspend request, but we are holding the SR_lock so we
1838 // can't just self-suspend. So we temporarily drop the lock
1839 // and then self-suspend.
1840 }
1841
1842 ThreadBlockInVM tbivm(this);
1843 java_suspend_self();
1844
1845 // We're done with this suspend request, but we have to loop around
1846 // and check again. Eventually we will get SR_lock without a pending
1847 // external suspend request and will be able to mark ourselves as
1848 // exiting.
1849 }
1850 // no more external suspends are allowed at this point
1851 } else {
1852 // before_exit() has already posted JVMTI THREAD_END events
1853 }
1854
1855 // Notify waiters on thread object. This has to be done after exit() is called
1856 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1857 // group should have the destroyed bit set before waiters are notified).
1858 ensure_join(this);
1859 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1860
1861 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1862 // held by this thread must be released. A detach operation must only
1863 // get here if there are no Java frames on the stack. Therefore, any
1864 // owned monitors at this point MUST be JNI-acquired monitors which are
1865 // pre-inflated and in the monitor cache.
1866 //
1867 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1868 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1869 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1870 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1871 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1872 }
1873
1874 // These things needs to be done while we are still a Java Thread. Make sure that thread
1875 // is in a consistent state, in case GC happens
1876 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1877
1878 if (active_handles() != NULL) {
1879 JNIHandleBlock* block = active_handles();
1880 set_active_handles(NULL);
1881 JNIHandleBlock::release_block(block);
1882 }
1883
1884 if (free_handle_block() != NULL) {
1885 JNIHandleBlock* block = free_handle_block();
1886 set_free_handle_block(NULL);
1887 JNIHandleBlock::release_block(block);
1888 }
1889
1890 // These have to be removed while this is still a valid thread.
1891 remove_stack_guard_pages();
1892
1893 if (UseTLAB) {
1894 tlab().make_parsable(true); // retire TLAB
1895 }
1896
1897 if (JvmtiEnv::environments_might_exist()) {
1898 JvmtiExport::cleanup_thread(this);
1899 }
1900
1901 // We must flush any deferred card marks before removing a thread from
1902 // the list of active threads.
1903 Universe::heap()->flush_deferred_store_barrier(this);
1904 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1905
1906 #if INCLUDE_ALL_GCS
1907 // We must flush the G1-related buffers before removing a thread
1908 // from the list of active threads. We must do this after any deferred
1909 // card marks have been flushed (above) so that any entries that are
1910 // added to the thread's dirty card queue as a result are not lost.
1911 if (UseG1GC) {
1912 flush_barrier_queues();
1913 }
1914 #endif // INCLUDE_ALL_GCS
1915
1916 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1917 Threads::remove(this);
1918 }
1919
1920 #if INCLUDE_ALL_GCS
1921 // Flush G1-related queues.
1922 void JavaThread::flush_barrier_queues() {
1923 satb_mark_queue().flush();
1924 dirty_card_queue().flush();
1925 }
1926
1927 void JavaThread::initialize_queues() {
1928 assert(!SafepointSynchronize::is_at_safepoint(),
1929 "we should not be at a safepoint");
1930
1931 ObjPtrQueue& satb_queue = satb_mark_queue();
1932 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1933 // The SATB queue should have been constructed with its active
1934 // field set to false.
1935 assert(!satb_queue.is_active(), "SATB queue should not be active");
1936 assert(satb_queue.is_empty(), "SATB queue should be empty");
1937 // If we are creating the thread during a marking cycle, we should
1938 // set the active field of the SATB queue to true.
1939 if (satb_queue_set.is_active()) {
1940 satb_queue.set_active(true);
1941 }
1942
1943 DirtyCardQueue& dirty_queue = dirty_card_queue();
1944 // The dirty card queue should have been constructed with its
1945 // active field set to true.
1946 assert(dirty_queue.is_active(), "dirty card queue should be active");
1947 }
1948 #endif // INCLUDE_ALL_GCS
1949
1950 void JavaThread::cleanup_failed_attach_current_thread() {
1951 if (get_thread_profiler() != NULL) {
1952 get_thread_profiler()->disengage();
1953 ResourceMark rm;
1954 get_thread_profiler()->print(get_thread_name());
1955 }
1956
1957 if (active_handles() != NULL) {
1958 JNIHandleBlock* block = active_handles();
1959 set_active_handles(NULL);
1960 JNIHandleBlock::release_block(block);
1961 }
1962
1963 if (free_handle_block() != NULL) {
1964 JNIHandleBlock* block = free_handle_block();
1965 set_free_handle_block(NULL);
1966 JNIHandleBlock::release_block(block);
1967 }
1968
1969 // These have to be removed while this is still a valid thread.
1970 remove_stack_guard_pages();
1971
1972 if (UseTLAB) {
1973 tlab().make_parsable(true); // retire TLAB, if any
1974 }
1975
1976 #if INCLUDE_ALL_GCS
1977 if (UseG1GC) {
1978 flush_barrier_queues();
1979 }
1980 #endif // INCLUDE_ALL_GCS
1981
1982 Threads::remove(this);
1983 delete this;
1984 }
1985
1986
1987
1988
1989 JavaThread* JavaThread::active() {
1990 Thread* thread = ThreadLocalStorage::thread();
1991 assert(thread != NULL, "just checking");
1992 if (thread->is_Java_thread()) {
1993 return (JavaThread*) thread;
1994 } else {
1995 assert(thread->is_VM_thread(), "this must be a vm thread");
1996 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1997 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1998 assert(ret->is_Java_thread(), "must be a Java thread");
1999 return ret;
2000 }
2001 }
2002
2003 bool JavaThread::is_lock_owned(address adr) const {
2004 if (Thread::is_lock_owned(adr)) return true;
2005
2006 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2007 if (chunk->contains(adr)) return true;
2008 }
2009
2010 return false;
2011 }
2012
2013
2014 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2015 chunk->set_next(monitor_chunks());
2016 set_monitor_chunks(chunk);
2017 }
2018
2019 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2020 guarantee(monitor_chunks() != NULL, "must be non empty");
2021 if (monitor_chunks() == chunk) {
2022 set_monitor_chunks(chunk->next());
2023 } else {
2024 MonitorChunk* prev = monitor_chunks();
2025 while (prev->next() != chunk) prev = prev->next();
2026 prev->set_next(chunk->next());
2027 }
2028 }
2029
2030 // JVM support.
2031
2032 // Note: this function shouldn't block if it's called in
2033 // _thread_in_native_trans state (such as from
2034 // check_special_condition_for_native_trans()).
2035 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2036
2037 if (has_last_Java_frame() && has_async_condition()) {
2038 // If we are at a polling page safepoint (not a poll return)
2039 // then we must defer async exception because live registers
2040 // will be clobbered by the exception path. Poll return is
2041 // ok because the call we a returning from already collides
2042 // with exception handling registers and so there is no issue.
2043 // (The exception handling path kills call result registers but
2044 // this is ok since the exception kills the result anyway).
2045
2046 if (is_at_poll_safepoint()) {
2047 // if the code we are returning to has deoptimized we must defer
2048 // the exception otherwise live registers get clobbered on the
2049 // exception path before deoptimization is able to retrieve them.
2050 //
2051 RegisterMap map(this, false);
2052 frame caller_fr = last_frame().sender(&map);
2053 assert(caller_fr.is_compiled_frame(), "what?");
2054 if (caller_fr.is_deoptimized_frame()) {
2055 if (TraceExceptions) {
2056 ResourceMark rm;
2057 tty->print_cr("deferred async exception at compiled safepoint");
2058 }
2059 return;
2060 }
2061 }
2062 }
2063
2064 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2065 if (condition == _no_async_condition) {
2066 // Conditions have changed since has_special_runtime_exit_condition()
2067 // was called:
2068 // - if we were here only because of an external suspend request,
2069 // then that was taken care of above (or cancelled) so we are done
2070 // - if we were here because of another async request, then it has
2071 // been cleared between the has_special_runtime_exit_condition()
2072 // and now so again we are done
2073 return;
2074 }
2075
2076 // Check for pending async. exception
2077 if (_pending_async_exception != NULL) {
2078 // Only overwrite an already pending exception, if it is not a threadDeath.
2079 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2080
2081 // We cannot call Exceptions::_throw(...) here because we cannot block
2082 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2083
2084 if (TraceExceptions) {
2085 ResourceMark rm;
2086 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2087 if (has_last_Java_frame() ) {
2088 frame f = last_frame();
2089 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2090 }
2091 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2092 }
2093 _pending_async_exception = NULL;
2094 clear_has_async_exception();
2095 }
2096 }
2097
2098 if (check_unsafe_error &&
2099 condition == _async_unsafe_access_error && !has_pending_exception()) {
2100 condition = _no_async_condition; // done
2101 switch (thread_state()) {
2102 case _thread_in_vm:
2103 {
2104 JavaThread* THREAD = this;
2105 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2106 }
2107 case _thread_in_native:
2108 {
2109 ThreadInVMfromNative tiv(this);
2110 JavaThread* THREAD = this;
2111 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2112 }
2113 case _thread_in_Java:
2114 {
2115 ThreadInVMfromJava tiv(this);
2116 JavaThread* THREAD = this;
2117 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2118 }
2119 default:
2120 ShouldNotReachHere();
2121 }
2122 }
2123
2124 assert(condition == _no_async_condition || has_pending_exception() ||
2125 (!check_unsafe_error && condition == _async_unsafe_access_error),
2126 "must have handled the async condition, if no exception");
2127 }
2128
2129 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2130 //
2131 // Check for pending external suspend. Internal suspend requests do
2132 // not use handle_special_runtime_exit_condition().
2133 // If JNIEnv proxies are allowed, don't self-suspend if the target
2134 // thread is not the current thread. In older versions of jdbx, jdbx
2135 // threads could call into the VM with another thread's JNIEnv so we
2136 // can be here operating on behalf of a suspended thread (4432884).
2137 bool do_self_suspend = is_external_suspend_with_lock();
2138 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2139 //
2140 // Because thread is external suspended the safepoint code will count
2141 // thread as at a safepoint. This can be odd because we can be here
2142 // as _thread_in_Java which would normally transition to _thread_blocked
2143 // at a safepoint. We would like to mark the thread as _thread_blocked
2144 // before calling java_suspend_self like all other callers of it but
2145 // we must then observe proper safepoint protocol. (We can't leave
2146 // _thread_blocked with a safepoint in progress). However we can be
2147 // here as _thread_in_native_trans so we can't use a normal transition
2148 // constructor/destructor pair because they assert on that type of
2149 // transition. We could do something like:
2150 //
2151 // JavaThreadState state = thread_state();
2152 // set_thread_state(_thread_in_vm);
2153 // {
2154 // ThreadBlockInVM tbivm(this);
2155 // java_suspend_self()
2156 // }
2157 // set_thread_state(_thread_in_vm_trans);
2158 // if (safepoint) block;
2159 // set_thread_state(state);
2160 //
2161 // but that is pretty messy. Instead we just go with the way the
2162 // code has worked before and note that this is the only path to
2163 // java_suspend_self that doesn't put the thread in _thread_blocked
2164 // mode.
2165
2166 frame_anchor()->make_walkable(this);
2167 java_suspend_self();
2168
2169 // We might be here for reasons in addition to the self-suspend request
2170 // so check for other async requests.
2171 }
2172
2173 if (check_asyncs) {
2174 check_and_handle_async_exceptions();
2175 }
2176 }
2177
2178 void JavaThread::send_thread_stop(oop java_throwable) {
2179 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2180 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2181 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2182
2183 // Do not throw asynchronous exceptions against the compiler thread
2184 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2185 if (is_Compiler_thread()) return;
2186
2187 {
2188 // Actually throw the Throwable against the target Thread - however
2189 // only if there is no thread death exception installed already.
2190 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2191 // If the topmost frame is a runtime stub, then we are calling into
2192 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2193 // must deoptimize the caller before continuing, as the compiled exception handler table
2194 // may not be valid
2195 if (has_last_Java_frame()) {
2196 frame f = last_frame();
2197 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2198 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2199 RegisterMap reg_map(this, UseBiasedLocking);
2200 frame compiled_frame = f.sender(®_map);
2201 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2202 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2203 }
2204 }
2205 }
2206
2207 // Set async. pending exception in thread.
2208 set_pending_async_exception(java_throwable);
2209
2210 if (TraceExceptions) {
2211 ResourceMark rm;
2212 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2213 }
2214 // for AbortVMOnException flag
2215 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2216 }
2217 }
2218
2219
2220 // Interrupt thread so it will wake up from a potential wait()
2221 Thread::interrupt(this);
2222 }
2223
2224 // External suspension mechanism.
2225 //
2226 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2227 // to any VM_locks and it is at a transition
2228 // Self-suspension will happen on the transition out of the vm.
2229 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2230 //
2231 // Guarantees on return:
2232 // + Target thread will not execute any new bytecode (that's why we need to
2233 // force a safepoint)
2234 // + Target thread will not enter any new monitors
2235 //
2236 void JavaThread::java_suspend() {
2237 { MutexLocker mu(Threads_lock);
2238 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2239 return;
2240 }
2241 }
2242
2243 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2244 if (!is_external_suspend()) {
2245 // a racing resume has cancelled us; bail out now
2246 return;
2247 }
2248
2249 // suspend is done
2250 uint32_t debug_bits = 0;
2251 // Warning: is_ext_suspend_completed() may temporarily drop the
2252 // SR_lock to allow the thread to reach a stable thread state if
2253 // it is currently in a transient thread state.
2254 if (is_ext_suspend_completed(false /* !called_by_wait */,
2255 SuspendRetryDelay, &debug_bits) ) {
2256 return;
2257 }
2258 }
2259
2260 VM_ForceSafepoint vm_suspend;
2261 VMThread::execute(&vm_suspend);
2262 }
2263
2264 // Part II of external suspension.
2265 // A JavaThread self suspends when it detects a pending external suspend
2266 // request. This is usually on transitions. It is also done in places
2267 // where continuing to the next transition would surprise the caller,
2268 // e.g., monitor entry.
2269 //
2270 // Returns the number of times that the thread self-suspended.
2271 //
2272 // Note: DO NOT call java_suspend_self() when you just want to block current
2273 // thread. java_suspend_self() is the second stage of cooperative
2274 // suspension for external suspend requests and should only be used
2275 // to complete an external suspend request.
2276 //
2277 int JavaThread::java_suspend_self() {
2278 int ret = 0;
2279
2280 // we are in the process of exiting so don't suspend
2281 if (is_exiting()) {
2282 clear_external_suspend();
2283 return ret;
2284 }
2285
2286 assert(_anchor.walkable() ||
2287 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2288 "must have walkable stack");
2289
2290 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2291
2292 assert(!this->is_ext_suspended(),
2293 "a thread trying to self-suspend should not already be suspended");
2294
2295 if (this->is_suspend_equivalent()) {
2296 // If we are self-suspending as a result of the lifting of a
2297 // suspend equivalent condition, then the suspend_equivalent
2298 // flag is not cleared until we set the ext_suspended flag so
2299 // that wait_for_ext_suspend_completion() returns consistent
2300 // results.
2301 this->clear_suspend_equivalent();
2302 }
2303
2304 // A racing resume may have cancelled us before we grabbed SR_lock
2305 // above. Or another external suspend request could be waiting for us
2306 // by the time we return from SR_lock()->wait(). The thread
2307 // that requested the suspension may already be trying to walk our
2308 // stack and if we return now, we can change the stack out from under
2309 // it. This would be a "bad thing (TM)" and cause the stack walker
2310 // to crash. We stay self-suspended until there are no more pending
2311 // external suspend requests.
2312 while (is_external_suspend()) {
2313 ret++;
2314 this->set_ext_suspended();
2315
2316 // _ext_suspended flag is cleared by java_resume()
2317 while (is_ext_suspended()) {
2318 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2319 }
2320 }
2321
2322 return ret;
2323 }
2324
2325 #ifdef ASSERT
2326 // verify the JavaThread has not yet been published in the Threads::list, and
2327 // hence doesn't need protection from concurrent access at this stage
2328 void JavaThread::verify_not_published() {
2329 if (!Threads_lock->owned_by_self()) {
2330 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2331 assert( !Threads::includes(this),
2332 "java thread shouldn't have been published yet!");
2333 }
2334 else {
2335 assert( !Threads::includes(this),
2336 "java thread shouldn't have been published yet!");
2337 }
2338 }
2339 #endif
2340
2341 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2342 // progress or when _suspend_flags is non-zero.
2343 // Current thread needs to self-suspend if there is a suspend request and/or
2344 // block if a safepoint is in progress.
2345 // Async exception ISN'T checked.
2346 // Note only the ThreadInVMfromNative transition can call this function
2347 // directly and when thread state is _thread_in_native_trans
2348 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2349 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2350
2351 JavaThread *curJT = JavaThread::current();
2352 bool do_self_suspend = thread->is_external_suspend();
2353
2354 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2355
2356 // If JNIEnv proxies are allowed, don't self-suspend if the target
2357 // thread is not the current thread. In older versions of jdbx, jdbx
2358 // threads could call into the VM with another thread's JNIEnv so we
2359 // can be here operating on behalf of a suspended thread (4432884).
2360 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2361 JavaThreadState state = thread->thread_state();
2362
2363 // We mark this thread_blocked state as a suspend-equivalent so
2364 // that a caller to is_ext_suspend_completed() won't be confused.
2365 // The suspend-equivalent state is cleared by java_suspend_self().
2366 thread->set_suspend_equivalent();
2367
2368 // If the safepoint code sees the _thread_in_native_trans state, it will
2369 // wait until the thread changes to other thread state. There is no
2370 // guarantee on how soon we can obtain the SR_lock and complete the
2371 // self-suspend request. It would be a bad idea to let safepoint wait for
2372 // too long. Temporarily change the state to _thread_blocked to
2373 // let the VM thread know that this thread is ready for GC. The problem
2374 // of changing thread state is that safepoint could happen just after
2375 // java_suspend_self() returns after being resumed, and VM thread will
2376 // see the _thread_blocked state. We must check for safepoint
2377 // after restoring the state and make sure we won't leave while a safepoint
2378 // is in progress.
2379 thread->set_thread_state(_thread_blocked);
2380 thread->java_suspend_self();
2381 thread->set_thread_state(state);
2382 // Make sure new state is seen by VM thread
2383 if (os::is_MP()) {
2384 if (UseMembar) {
2385 // Force a fence between the write above and read below
2386 OrderAccess::fence();
2387 } else {
2388 // Must use this rather than serialization page in particular on Windows
2389 InterfaceSupport::serialize_memory(thread);
2390 }
2391 }
2392 }
2393
2394 if (SafepointSynchronize::do_call_back()) {
2395 // If we are safepointing, then block the caller which may not be
2396 // the same as the target thread (see above).
2397 SafepointSynchronize::block(curJT);
2398 }
2399
2400 if (thread->is_deopt_suspend()) {
2401 thread->clear_deopt_suspend();
2402 RegisterMap map(thread, false);
2403 frame f = thread->last_frame();
2404 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2405 f = f.sender(&map);
2406 }
2407 if (f.id() == thread->must_deopt_id()) {
2408 thread->clear_must_deopt_id();
2409 f.deoptimize(thread);
2410 } else {
2411 fatal("missed deoptimization!");
2412 }
2413 }
2414 }
2415
2416 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2417 // progress or when _suspend_flags is non-zero.
2418 // Current thread needs to self-suspend if there is a suspend request and/or
2419 // block if a safepoint is in progress.
2420 // Also check for pending async exception (not including unsafe access error).
2421 // Note only the native==>VM/Java barriers can call this function and when
2422 // thread state is _thread_in_native_trans.
2423 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2424 check_safepoint_and_suspend_for_native_trans(thread);
2425
2426 if (thread->has_async_exception()) {
2427 // We are in _thread_in_native_trans state, don't handle unsafe
2428 // access error since that may block.
2429 thread->check_and_handle_async_exceptions(false);
2430 }
2431 }
2432
2433 // This is a variant of the normal
2434 // check_special_condition_for_native_trans with slightly different
2435 // semantics for use by critical native wrappers. It does all the
2436 // normal checks but also performs the transition back into
2437 // thread_in_Java state. This is required so that critical natives
2438 // can potentially block and perform a GC if they are the last thread
2439 // exiting the GC_locker.
2440 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2441 check_special_condition_for_native_trans(thread);
2442
2443 // Finish the transition
2444 thread->set_thread_state(_thread_in_Java);
2445
2446 if (thread->do_critical_native_unlock()) {
2447 ThreadInVMfromJavaNoAsyncException tiv(thread);
2448 GC_locker::unlock_critical(thread);
2449 thread->clear_critical_native_unlock();
2450 }
2451 }
2452
2453 // We need to guarantee the Threads_lock here, since resumes are not
2454 // allowed during safepoint synchronization
2455 // Can only resume from an external suspension
2456 void JavaThread::java_resume() {
2457 assert_locked_or_safepoint(Threads_lock);
2458
2459 // Sanity check: thread is gone, has started exiting or the thread
2460 // was not externally suspended.
2461 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2462 return;
2463 }
2464
2465 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2466
2467 clear_external_suspend();
2468
2469 if (is_ext_suspended()) {
2470 clear_ext_suspended();
2471 SR_lock()->notify_all();
2472 }
2473 }
2474
2475 void JavaThread::create_stack_guard_pages() {
2476 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2477 address low_addr = stack_base() - stack_size();
2478 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2479
2480 int allocate = os::allocate_stack_guard_pages();
2481 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2482
2483 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2484 warning("Attempt to allocate stack guard pages failed.");
2485 return;
2486 }
2487
2488 if (os::guard_memory((char *) low_addr, len)) {
2489 _stack_guard_state = stack_guard_enabled;
2490 } else {
2491 warning("Attempt to protect stack guard pages failed.");
2492 if (os::uncommit_memory((char *) low_addr, len)) {
2493 warning("Attempt to deallocate stack guard pages failed.");
2494 }
2495 }
2496 }
2497
2498 void JavaThread::remove_stack_guard_pages() {
2499 assert(Thread::current() == this, "from different thread");
2500 if (_stack_guard_state == stack_guard_unused) return;
2501 address low_addr = stack_base() - stack_size();
2502 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2503
2504 if (os::allocate_stack_guard_pages()) {
2505 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2506 _stack_guard_state = stack_guard_unused;
2507 } else {
2508 warning("Attempt to deallocate stack guard pages failed.");
2509 }
2510 } else {
2511 if (_stack_guard_state == stack_guard_unused) return;
2512 if (os::unguard_memory((char *) low_addr, len)) {
2513 _stack_guard_state = stack_guard_unused;
2514 } else {
2515 warning("Attempt to unprotect stack guard pages failed.");
2516 }
2517 }
2518 }
2519
2520 void JavaThread::enable_stack_yellow_zone() {
2521 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2522 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2523
2524 // The base notation is from the stacks point of view, growing downward.
2525 // We need to adjust it to work correctly with guard_memory()
2526 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2527
2528 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2529 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2530
2531 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2532 _stack_guard_state = stack_guard_enabled;
2533 } else {
2534 warning("Attempt to guard stack yellow zone failed.");
2535 }
2536 enable_register_stack_guard();
2537 }
2538
2539 void JavaThread::disable_stack_yellow_zone() {
2540 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2541 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2542
2543 // Simply return if called for a thread that does not use guard pages.
2544 if (_stack_guard_state == stack_guard_unused) return;
2545
2546 // The base notation is from the stacks point of view, growing downward.
2547 // We need to adjust it to work correctly with guard_memory()
2548 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2549
2550 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2551 _stack_guard_state = stack_guard_yellow_disabled;
2552 } else {
2553 warning("Attempt to unguard stack yellow zone failed.");
2554 }
2555 disable_register_stack_guard();
2556 }
2557
2558 void JavaThread::enable_stack_red_zone() {
2559 // The base notation is from the stacks point of view, growing downward.
2560 // We need to adjust it to work correctly with guard_memory()
2561 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2562 address base = stack_red_zone_base() - stack_red_zone_size();
2563
2564 guarantee(base < stack_base(),"Error calculating stack red zone");
2565 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2566
2567 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2568 warning("Attempt to guard stack red zone failed.");
2569 }
2570 }
2571
2572 void JavaThread::disable_stack_red_zone() {
2573 // The base notation is from the stacks point of view, growing downward.
2574 // We need to adjust it to work correctly with guard_memory()
2575 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2576 address base = stack_red_zone_base() - stack_red_zone_size();
2577 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2578 warning("Attempt to unguard stack red zone failed.");
2579 }
2580 }
2581
2582 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2583 // ignore is there is no stack
2584 if (!has_last_Java_frame()) return;
2585 // traverse the stack frames. Starts from top frame.
2586 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2587 frame* fr = fst.current();
2588 f(fr, fst.register_map());
2589 }
2590 }
2591
2592
2593 #ifndef PRODUCT
2594 // Deoptimization
2595 // Function for testing deoptimization
2596 void JavaThread::deoptimize() {
2597 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2598 StackFrameStream fst(this, UseBiasedLocking);
2599 bool deopt = false; // Dump stack only if a deopt actually happens.
2600 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2601 // Iterate over all frames in the thread and deoptimize
2602 for(; !fst.is_done(); fst.next()) {
2603 if(fst.current()->can_be_deoptimized()) {
2604
2605 if (only_at) {
2606 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2607 // consists of comma or carriage return separated numbers so
2608 // search for the current bci in that string.
2609 address pc = fst.current()->pc();
2610 nmethod* nm = (nmethod*) fst.current()->cb();
2611 ScopeDesc* sd = nm->scope_desc_at( pc);
2612 char buffer[8];
2613 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2614 size_t len = strlen(buffer);
2615 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2616 while (found != NULL) {
2617 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2618 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2619 // Check that the bci found is bracketed by terminators.
2620 break;
2621 }
2622 found = strstr(found + 1, buffer);
2623 }
2624 if (!found) {
2625 continue;
2626 }
2627 }
2628
2629 if (DebugDeoptimization && !deopt) {
2630 deopt = true; // One-time only print before deopt
2631 tty->print_cr("[BEFORE Deoptimization]");
2632 trace_frames();
2633 trace_stack();
2634 }
2635 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2636 }
2637 }
2638
2639 if (DebugDeoptimization && deopt) {
2640 tty->print_cr("[AFTER Deoptimization]");
2641 trace_frames();
2642 }
2643 }
2644
2645
2646 // Make zombies
2647 void JavaThread::make_zombies() {
2648 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2649 if (fst.current()->can_be_deoptimized()) {
2650 // it is a Java nmethod
2651 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2652 nm->make_not_entrant();
2653 }
2654 }
2655 }
2656 #endif // PRODUCT
2657
2658
2659 void JavaThread::deoptimized_wrt_marked_nmethods() {
2660 if (!has_last_Java_frame()) return;
2661 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2662 StackFrameStream fst(this, UseBiasedLocking);
2663 for(; !fst.is_done(); fst.next()) {
2664 if (fst.current()->should_be_deoptimized()) {
2665 if (LogCompilation && xtty != NULL) {
2666 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2667 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2668 this->name(), nm != NULL ? nm->compile_id() : -1);
2669 }
2670
2671 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2672 }
2673 }
2674 }
2675
2676
2677 // GC support
2678 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2679
2680 void JavaThread::gc_epilogue() {
2681 frames_do(frame_gc_epilogue);
2682 }
2683
2684
2685 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2686
2687 void JavaThread::gc_prologue() {
2688 frames_do(frame_gc_prologue);
2689 }
2690
2691 // If the caller is a NamedThread, then remember, in the current scope,
2692 // the given JavaThread in its _processed_thread field.
2693 class RememberProcessedThread: public StackObj {
2694 NamedThread* _cur_thr;
2695 public:
2696 RememberProcessedThread(JavaThread* jthr) {
2697 Thread* thread = Thread::current();
2698 if (thread->is_Named_thread()) {
2699 _cur_thr = (NamedThread *)thread;
2700 _cur_thr->set_processed_thread(jthr);
2701 } else {
2702 _cur_thr = NULL;
2703 }
2704 }
2705
2706 ~RememberProcessedThread() {
2707 if (_cur_thr) {
2708 _cur_thr->set_processed_thread(NULL);
2709 }
2710 }
2711 };
2712
2713 void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
2714 // Verify that the deferred card marks have been flushed.
2715 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2716
2717 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2718 // since there may be more than one thread using each ThreadProfiler.
2719
2720 // Traverse the GCHandles
2721 Thread::oops_do(f, cld_f, cf);
2722
2723 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2724 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2725
2726 if (has_last_Java_frame()) {
2727 // Record JavaThread to GC thread
2728 RememberProcessedThread rpt(this);
2729
2730 // Traverse the privileged stack
2731 if (_privileged_stack_top != NULL) {
2732 _privileged_stack_top->oops_do(f);
2733 }
2734
2735 // traverse the registered growable array
2736 if (_array_for_gc != NULL) {
2737 for (int index = 0; index < _array_for_gc->length(); index++) {
2738 f->do_oop(_array_for_gc->adr_at(index));
2739 }
2740 }
2741
2742 // Traverse the monitor chunks
2743 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2744 chunk->oops_do(f);
2745 }
2746
2747 // Traverse the execution stack
2748 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2749 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2750 }
2751 }
2752
2753 // callee_target is never live across a gc point so NULL it here should
2754 // it still contain a methdOop.
2755
2756 set_callee_target(NULL);
2757
2758 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2759 // If we have deferred set_locals there might be oops waiting to be
2760 // written
2761 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2762 if (list != NULL) {
2763 for (int i = 0; i < list->length(); i++) {
2764 list->at(i)->oops_do(f);
2765 }
2766 }
2767
2768 // Traverse instance variables at the end since the GC may be moving things
2769 // around using this function
2770 f->do_oop((oop*) &_threadObj);
2771 f->do_oop((oop*) &_vm_result);
2772 f->do_oop((oop*) &_exception_oop);
2773 f->do_oop((oop*) &_pending_async_exception);
2774
2775 if (jvmti_thread_state() != NULL) {
2776 jvmti_thread_state()->oops_do(f);
2777 }
2778 }
2779
2780 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2781 Thread::nmethods_do(cf); // (super method is a no-op)
2782
2783 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2784 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2785
2786 if (has_last_Java_frame()) {
2787 // Traverse the execution stack
2788 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2789 fst.current()->nmethods_do(cf);
2790 }
2791 }
2792 }
2793
2794 void JavaThread::metadata_do(void f(Metadata*)) {
2795 Thread::metadata_do(f);
2796 if (has_last_Java_frame()) {
2797 // Traverse the execution stack to call f() on the methods in the stack
2798 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2799 fst.current()->metadata_do(f);
2800 }
2801 } else if (is_Compiler_thread()) {
2802 // need to walk ciMetadata in current compile tasks to keep alive.
2803 CompilerThread* ct = (CompilerThread*)this;
2804 if (ct->env() != NULL) {
2805 ct->env()->metadata_do(f);
2806 }
2807 }
2808 }
2809
2810 // Printing
2811 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2812 switch (_thread_state) {
2813 case _thread_uninitialized: return "_thread_uninitialized";
2814 case _thread_new: return "_thread_new";
2815 case _thread_new_trans: return "_thread_new_trans";
2816 case _thread_in_native: return "_thread_in_native";
2817 case _thread_in_native_trans: return "_thread_in_native_trans";
2818 case _thread_in_vm: return "_thread_in_vm";
2819 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2820 case _thread_in_Java: return "_thread_in_Java";
2821 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2822 case _thread_blocked: return "_thread_blocked";
2823 case _thread_blocked_trans: return "_thread_blocked_trans";
2824 default: return "unknown thread state";
2825 }
2826 }
2827
2828 #ifndef PRODUCT
2829 void JavaThread::print_thread_state_on(outputStream *st) const {
2830 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2831 };
2832 void JavaThread::print_thread_state() const {
2833 print_thread_state_on(tty);
2834 };
2835 #endif // PRODUCT
2836
2837 // Called by Threads::print() for VM_PrintThreads operation
2838 void JavaThread::print_on(outputStream *st) const {
2839 st->print("\"%s\" ", get_thread_name());
2840 oop thread_oop = threadObj();
2841 if (thread_oop != NULL) {
2842 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2843 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2844 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2845 }
2846 Thread::print_on(st);
2847 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2848 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2849 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2850 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2851 }
2852 #ifndef PRODUCT
2853 print_thread_state_on(st);
2854 _safepoint_state->print_on(st);
2855 #endif // PRODUCT
2856 }
2857
2858 // Called by fatal error handler. The difference between this and
2859 // JavaThread::print() is that we can't grab lock or allocate memory.
2860 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2861 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2862 oop thread_obj = threadObj();
2863 if (thread_obj != NULL) {
2864 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2865 }
2866 st->print(" [");
2867 st->print("%s", _get_thread_state_name(_thread_state));
2868 if (osthread()) {
2869 st->print(", id=%d", osthread()->thread_id());
2870 }
2871 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2872 _stack_base - _stack_size, _stack_base);
2873 st->print("]");
2874 return;
2875 }
2876
2877 // Verification
2878
2879 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2880
2881 void JavaThread::verify() {
2882 // Verify oops in the thread.
2883 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2884
2885 // Verify the stack frames.
2886 frames_do(frame_verify);
2887 }
2888
2889 // CR 6300358 (sub-CR 2137150)
2890 // Most callers of this method assume that it can't return NULL but a
2891 // thread may not have a name whilst it is in the process of attaching to
2892 // the VM - see CR 6412693, and there are places where a JavaThread can be
2893 // seen prior to having it's threadObj set (eg JNI attaching threads and
2894 // if vm exit occurs during initialization). These cases can all be accounted
2895 // for such that this method never returns NULL.
2896 const char* JavaThread::get_thread_name() const {
2897 #ifdef ASSERT
2898 // early safepoints can hit while current thread does not yet have TLS
2899 if (!SafepointSynchronize::is_at_safepoint()) {
2900 Thread *cur = Thread::current();
2901 if (!(cur->is_Java_thread() && cur == this)) {
2902 // Current JavaThreads are allowed to get their own name without
2903 // the Threads_lock.
2904 assert_locked_or_safepoint(Threads_lock);
2905 }
2906 }
2907 #endif // ASSERT
2908 return get_thread_name_string();
2909 }
2910
2911 // Returns a non-NULL representation of this thread's name, or a suitable
2912 // descriptive string if there is no set name
2913 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2914 const char* name_str;
2915 oop thread_obj = threadObj();
2916 if (thread_obj != NULL) {
2917 typeArrayOop name = java_lang_Thread::name(thread_obj);
2918 if (name != NULL) {
2919 if (buf == NULL) {
2920 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2921 }
2922 else {
2923 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2924 }
2925 }
2926 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2927 name_str = "<no-name - thread is attaching>";
2928 }
2929 else {
2930 name_str = Thread::name();
2931 }
2932 }
2933 else {
2934 name_str = Thread::name();
2935 }
2936 assert(name_str != NULL, "unexpected NULL thread name");
2937 return name_str;
2938 }
2939
2940
2941 const char* JavaThread::get_threadgroup_name() const {
2942 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2943 oop thread_obj = threadObj();
2944 if (thread_obj != NULL) {
2945 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2946 if (thread_group != NULL) {
2947 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2948 // ThreadGroup.name can be null
2949 if (name != NULL) {
2950 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2951 return str;
2952 }
2953 }
2954 }
2955 return NULL;
2956 }
2957
2958 const char* JavaThread::get_parent_name() const {
2959 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2960 oop thread_obj = threadObj();
2961 if (thread_obj != NULL) {
2962 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2963 if (thread_group != NULL) {
2964 oop parent = java_lang_ThreadGroup::parent(thread_group);
2965 if (parent != NULL) {
2966 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2967 // ThreadGroup.name can be null
2968 if (name != NULL) {
2969 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2970 return str;
2971 }
2972 }
2973 }
2974 }
2975 return NULL;
2976 }
2977
2978 ThreadPriority JavaThread::java_priority() const {
2979 oop thr_oop = threadObj();
2980 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2981 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2982 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2983 return priority;
2984 }
2985
2986 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2987
2988 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2989 // Link Java Thread object <-> C++ Thread
2990
2991 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2992 // and put it into a new Handle. The Handle "thread_oop" can then
2993 // be used to pass the C++ thread object to other methods.
2994
2995 // Set the Java level thread object (jthread) field of the
2996 // new thread (a JavaThread *) to C++ thread object using the
2997 // "thread_oop" handle.
2998
2999 // Set the thread field (a JavaThread *) of the
3000 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3001
3002 Handle thread_oop(Thread::current(),
3003 JNIHandles::resolve_non_null(jni_thread));
3004 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3005 "must be initialized");
3006 set_threadObj(thread_oop());
3007 java_lang_Thread::set_thread(thread_oop(), this);
3008
3009 if (prio == NoPriority) {
3010 prio = java_lang_Thread::priority(thread_oop());
3011 assert(prio != NoPriority, "A valid priority should be present");
3012 }
3013
3014 // Push the Java priority down to the native thread; needs Threads_lock
3015 Thread::set_priority(this, prio);
3016
3017 // Add the new thread to the Threads list and set it in motion.
3018 // We must have threads lock in order to call Threads::add.
3019 // It is crucial that we do not block before the thread is
3020 // added to the Threads list for if a GC happens, then the java_thread oop
3021 // will not be visited by GC.
3022 Threads::add(this);
3023 }
3024
3025 oop JavaThread::current_park_blocker() {
3026 // Support for JSR-166 locks
3027 oop thread_oop = threadObj();
3028 if (thread_oop != NULL &&
3029 JDK_Version::current().supports_thread_park_blocker()) {
3030 return java_lang_Thread::park_blocker(thread_oop);
3031 }
3032 return NULL;
3033 }
3034
3035
3036 void JavaThread::print_stack_on(outputStream* st) {
3037 if (!has_last_Java_frame()) return;
3038 ResourceMark rm;
3039 HandleMark hm;
3040
3041 RegisterMap reg_map(this);
3042 vframe* start_vf = last_java_vframe(®_map);
3043 int count = 0;
3044 for (vframe* f = start_vf; f; f = f->sender() ) {
3045 if (f->is_java_frame()) {
3046 javaVFrame* jvf = javaVFrame::cast(f);
3047 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3048
3049 // Print out lock information
3050 if (JavaMonitorsInStackTrace) {
3051 jvf->print_lock_info_on(st, count);
3052 }
3053 } else {
3054 // Ignore non-Java frames
3055 }
3056
3057 // Bail-out case for too deep stacks
3058 count++;
3059 if (MaxJavaStackTraceDepth == count) return;
3060 }
3061 }
3062
3063
3064 // JVMTI PopFrame support
3065 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3066 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3067 if (in_bytes(size_in_bytes) != 0) {
3068 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3069 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3070 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3071 }
3072 }
3073
3074 void* JavaThread::popframe_preserved_args() {
3075 return _popframe_preserved_args;
3076 }
3077
3078 ByteSize JavaThread::popframe_preserved_args_size() {
3079 return in_ByteSize(_popframe_preserved_args_size);
3080 }
3081
3082 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3083 int sz = in_bytes(popframe_preserved_args_size());
3084 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3085 return in_WordSize(sz / wordSize);
3086 }
3087
3088 void JavaThread::popframe_free_preserved_args() {
3089 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3090 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3091 _popframe_preserved_args = NULL;
3092 _popframe_preserved_args_size = 0;
3093 }
3094
3095 #ifndef PRODUCT
3096
3097 void JavaThread::trace_frames() {
3098 tty->print_cr("[Describe stack]");
3099 int frame_no = 1;
3100 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3101 tty->print(" %d. ", frame_no++);
3102 fst.current()->print_value_on(tty,this);
3103 tty->cr();
3104 }
3105 }
3106
3107 class PrintAndVerifyOopClosure: public OopClosure {
3108 protected:
3109 template <class T> inline void do_oop_work(T* p) {
3110 oop obj = oopDesc::load_decode_heap_oop(p);
3111 if (obj == NULL) return;
3112 tty->print(INTPTR_FORMAT ": ", p);
3113 if (obj->is_oop_or_null()) {
3114 if (obj->is_objArray()) {
3115 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3116 } else {
3117 obj->print();
3118 }
3119 } else {
3120 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3121 }
3122 tty->cr();
3123 }
3124 public:
3125 virtual void do_oop(oop* p) { do_oop_work(p); }
3126 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3127 };
3128
3129
3130 static void oops_print(frame* f, const RegisterMap *map) {
3131 PrintAndVerifyOopClosure print;
3132 f->print_value();
3133 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3134 }
3135
3136 // Print our all the locations that contain oops and whether they are
3137 // valid or not. This useful when trying to find the oldest frame
3138 // where an oop has gone bad since the frame walk is from youngest to
3139 // oldest.
3140 void JavaThread::trace_oops() {
3141 tty->print_cr("[Trace oops]");
3142 frames_do(oops_print);
3143 }
3144
3145
3146 #ifdef ASSERT
3147 // Print or validate the layout of stack frames
3148 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3149 ResourceMark rm;
3150 PRESERVE_EXCEPTION_MARK;
3151 FrameValues values;
3152 int frame_no = 0;
3153 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3154 fst.current()->describe(values, ++frame_no);
3155 if (depth == frame_no) break;
3156 }
3157 if (validate_only) {
3158 values.validate();
3159 } else {
3160 tty->print_cr("[Describe stack layout]");
3161 values.print(this);
3162 }
3163 }
3164 #endif
3165
3166 void JavaThread::trace_stack_from(vframe* start_vf) {
3167 ResourceMark rm;
3168 int vframe_no = 1;
3169 for (vframe* f = start_vf; f; f = f->sender() ) {
3170 if (f->is_java_frame()) {
3171 javaVFrame::cast(f)->print_activation(vframe_no++);
3172 } else {
3173 f->print();
3174 }
3175 if (vframe_no > StackPrintLimit) {
3176 tty->print_cr("...<more frames>...");
3177 return;
3178 }
3179 }
3180 }
3181
3182
3183 void JavaThread::trace_stack() {
3184 if (!has_last_Java_frame()) return;
3185 ResourceMark rm;
3186 HandleMark hm;
3187 RegisterMap reg_map(this);
3188 trace_stack_from(last_java_vframe(®_map));
3189 }
3190
3191
3192 #endif // PRODUCT
3193
3194
3195 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3196 assert(reg_map != NULL, "a map must be given");
3197 frame f = last_frame();
3198 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3199 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3200 }
3201 return NULL;
3202 }
3203
3204
3205 Klass* JavaThread::security_get_caller_class(int depth) {
3206 vframeStream vfst(this);
3207 vfst.security_get_caller_frame(depth);
3208 if (!vfst.at_end()) {
3209 return vfst.method()->method_holder();
3210 }
3211 return NULL;
3212 }
3213
3214 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3215 assert(thread->is_Compiler_thread(), "must be compiler thread");
3216 CompileBroker::compiler_thread_loop();
3217 }
3218
3219 // Create a CompilerThread
3220 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3221 : JavaThread(&compiler_thread_entry) {
3222 _env = NULL;
3223 _log = NULL;
3224 _task = NULL;
3225 _queue = queue;
3226 _counters = counters;
3227 _buffer_blob = NULL;
3228 _scanned_nmethod = NULL;
3229
3230 #ifndef PRODUCT
3231 _ideal_graph_printer = NULL;
3232 #endif
3233 }
3234
3235 void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
3236 JavaThread::oops_do(f, cld_f, cf);
3237 if (_scanned_nmethod != NULL && cf != NULL) {
3238 // Safepoints can occur when the sweeper is scanning an nmethod so
3239 // process it here to make sure it isn't unloaded in the middle of
3240 // a scan.
3241 cf->do_code_blob(_scanned_nmethod);
3242 }
3243 }
3244
3245 // ======= Threads ========
3246
3247 // The Threads class links together all active threads, and provides
3248 // operations over all threads. It is protected by its own Mutex
3249 // lock, which is also used in other contexts to protect thread
3250 // operations from having the thread being operated on from exiting
3251 // and going away unexpectedly (e.g., safepoint synchronization)
3252
3253 JavaThread* Threads::_thread_list = NULL;
3254 int Threads::_number_of_threads = 0;
3255 int Threads::_number_of_non_daemon_threads = 0;
3256 int Threads::_return_code = 0;
3257 size_t JavaThread::_stack_size_at_create = 0;
3258 #ifdef ASSERT
3259 bool Threads::_vm_complete = false;
3260 #endif
3261
3262 // All JavaThreads
3263 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3264
3265 void os_stream();
3266
3267 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3268 void Threads::threads_do(ThreadClosure* tc) {
3269 assert_locked_or_safepoint(Threads_lock);
3270 // ALL_JAVA_THREADS iterates through all JavaThreads
3271 ALL_JAVA_THREADS(p) {
3272 tc->do_thread(p);
3273 }
3274 // Someday we could have a table or list of all non-JavaThreads.
3275 // For now, just manually iterate through them.
3276 tc->do_thread(VMThread::vm_thread());
3277 Universe::heap()->gc_threads_do(tc);
3278 WatcherThread *wt = WatcherThread::watcher_thread();
3279 // Strictly speaking, the following NULL check isn't sufficient to make sure
3280 // the data for WatcherThread is still valid upon being examined. However,
3281 // considering that WatchThread terminates when the VM is on the way to
3282 // exit at safepoint, the chance of the above is extremely small. The right
3283 // way to prevent termination of WatcherThread would be to acquire
3284 // Terminator_lock, but we can't do that without violating the lock rank
3285 // checking in some cases.
3286 if (wt != NULL)
3287 tc->do_thread(wt);
3288
3289 // If CompilerThreads ever become non-JavaThreads, add them here
3290 }
3291
3292 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3293
3294 extern void JDK_Version_init();
3295
3296 // Check version
3297 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3298
3299 // Initialize the output stream module
3300 ostream_init();
3301
3302 // Process java launcher properties.
3303 Arguments::process_sun_java_launcher_properties(args);
3304
3305 // Initialize the os module before using TLS
3306 os::init();
3307
3308 // Initialize system properties.
3309 Arguments::init_system_properties();
3310
3311 // So that JDK version can be used as a discrimintor when parsing arguments
3312 JDK_Version_init();
3313
3314 // Update/Initialize System properties after JDK version number is known
3315 Arguments::init_version_specific_system_properties();
3316
3317 // Parse arguments
3318 jint parse_result = Arguments::parse(args);
3319 if (parse_result != JNI_OK) return parse_result;
3320
3321 if (PauseAtStartup) {
3322 os::pause();
3323 }
3324
3325 #ifndef USDT2
3326 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3327 #else /* USDT2 */
3328 HOTSPOT_VM_INIT_BEGIN();
3329 #endif /* USDT2 */
3330
3331 // Record VM creation timing statistics
3332 TraceVmCreationTime create_vm_timer;
3333 create_vm_timer.start();
3334
3335 // Timing (must come after argument parsing)
3336 TraceTime timer("Create VM", TraceStartupTime);
3337
3338 // Initialize the os module after parsing the args
3339 jint os_init_2_result = os::init_2();
3340 if (os_init_2_result != JNI_OK) return os_init_2_result;
3341
3342 jint adjust_after_os_result = Arguments::adjust_after_os();
3343 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3344
3345 // intialize TLS
3346 ThreadLocalStorage::init();
3347
3348 // Bootstrap native memory tracking, so it can start recording memory
3349 // activities before worker thread is started. This is the first phase
3350 // of bootstrapping, VM is currently running in single-thread mode.
3351 MemTracker::bootstrap_single_thread();
3352
3353 // Initialize output stream logging
3354 ostream_init_log();
3355
3356 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3357 // Must be before create_vm_init_agents()
3358 if (Arguments::init_libraries_at_startup()) {
3359 convert_vm_init_libraries_to_agents();
3360 }
3361
3362 // Launch -agentlib/-agentpath and converted -Xrun agents
3363 if (Arguments::init_agents_at_startup()) {
3364 create_vm_init_agents();
3365 }
3366
3367 // Initialize Threads state
3368 _thread_list = NULL;
3369 _number_of_threads = 0;
3370 _number_of_non_daemon_threads = 0;
3371
3372 // Initialize global data structures and create system classes in heap
3373 vm_init_globals();
3374
3375 // Attach the main thread to this os thread
3376 JavaThread* main_thread = new JavaThread();
3377 main_thread->set_thread_state(_thread_in_vm);
3378 // must do this before set_active_handles and initialize_thread_local_storage
3379 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3380 // change the stack size recorded here to one based on the java thread
3381 // stacksize. This adjusted size is what is used to figure the placement
3382 // of the guard pages.
3383 main_thread->record_stack_base_and_size();
3384 main_thread->initialize_thread_local_storage();
3385
3386 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3387
3388 if (!main_thread->set_as_starting_thread()) {
3389 vm_shutdown_during_initialization(
3390 "Failed necessary internal allocation. Out of swap space");
3391 delete main_thread;
3392 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3393 return JNI_ENOMEM;
3394 }
3395
3396 // Enable guard page *after* os::create_main_thread(), otherwise it would
3397 // crash Linux VM, see notes in os_linux.cpp.
3398 main_thread->create_stack_guard_pages();
3399
3400 // Initialize Java-Level synchronization subsystem
3401 ObjectMonitor::Initialize() ;
3402
3403 // Second phase of bootstrapping, VM is about entering multi-thread mode
3404 MemTracker::bootstrap_multi_thread();
3405
3406 // Initialize global modules
3407 jint status = init_globals();
3408 if (status != JNI_OK) {
3409 delete main_thread;
3410 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3411 return status;
3412 }
3413
3414 // Should be done after the heap is fully created
3415 main_thread->cache_global_variables();
3416
3417 HandleMark hm;
3418
3419 { MutexLocker mu(Threads_lock);
3420 Threads::add(main_thread);
3421 }
3422
3423 // Any JVMTI raw monitors entered in onload will transition into
3424 // real raw monitor. VM is setup enough here for raw monitor enter.
3425 JvmtiExport::transition_pending_onload_raw_monitors();
3426
3427 // Fully start NMT
3428 MemTracker::start();
3429
3430 // Create the VMThread
3431 { TraceTime timer("Start VMThread", TraceStartupTime);
3432 VMThread::create();
3433 Thread* vmthread = VMThread::vm_thread();
3434
3435 if (!os::create_thread(vmthread, os::vm_thread))
3436 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3437
3438 // Wait for the VM thread to become ready, and VMThread::run to initialize
3439 // Monitors can have spurious returns, must always check another state flag
3440 {
3441 MutexLocker ml(Notify_lock);
3442 os::start_thread(vmthread);
3443 while (vmthread->active_handles() == NULL) {
3444 Notify_lock->wait();
3445 }
3446 }
3447 }
3448
3449 assert (Universe::is_fully_initialized(), "not initialized");
3450 if (VerifyDuringStartup) {
3451 // Make sure we're starting with a clean slate.
3452 VM_Verify verify_op;
3453 VMThread::execute(&verify_op);
3454 }
3455
3456 EXCEPTION_MARK;
3457
3458 // At this point, the Universe is initialized, but we have not executed
3459 // any byte code. Now is a good time (the only time) to dump out the
3460 // internal state of the JVM for sharing.
3461 if (DumpSharedSpaces) {
3462 MetaspaceShared::preload_and_dump(CHECK_0);
3463 ShouldNotReachHere();
3464 }
3465
3466 // Always call even when there are not JVMTI environments yet, since environments
3467 // may be attached late and JVMTI must track phases of VM execution
3468 JvmtiExport::enter_start_phase();
3469
3470 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3471 JvmtiExport::post_vm_start();
3472
3473 {
3474 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3475
3476 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3477 create_vm_init_libraries();
3478 }
3479
3480 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3481
3482 if (AggressiveOpts) {
3483 {
3484 // Forcibly initialize java/util/HashMap and mutate the private
3485 // static final "frontCacheEnabled" field before we start creating instances
3486 #ifdef ASSERT
3487 Klass* tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3488 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
3489 #endif
3490 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3491 KlassHandle k = KlassHandle(THREAD, k_o);
3492 guarantee(k.not_null(), "Must find java/util/HashMap");
3493 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3494 ik->initialize(CHECK_0);
3495 fieldDescriptor fd;
3496 // Possible we might not find this field; if so, don't break
3497 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3498 k()->java_mirror()->bool_field_put(fd.offset(), true);
3499 }
3500 }
3501
3502 if (UseStringCache) {
3503 // Forcibly initialize java/lang/StringValue and mutate the private
3504 // static final "stringCacheEnabled" field before we start creating instances
3505 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
3506 // Possible that StringValue isn't present: if so, silently don't break
3507 if (k_o != NULL) {
3508 KlassHandle k = KlassHandle(THREAD, k_o);
3509 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3510 ik->initialize(CHECK_0);
3511 fieldDescriptor fd;
3512 // Possible we might not find this field: if so, silently don't break
3513 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3514 k()->java_mirror()->bool_field_put(fd.offset(), true);
3515 }
3516 }
3517 }
3518 }
3519
3520 // Initialize java_lang.System (needed before creating the thread)
3521 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3522 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3523 Handle thread_group = create_initial_thread_group(CHECK_0);
3524 Universe::set_main_thread_group(thread_group());
3525 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3526 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3527 main_thread->set_threadObj(thread_object);
3528 // Set thread status to running since main thread has
3529 // been started and running.
3530 java_lang_Thread::set_thread_status(thread_object,
3531 java_lang_Thread::RUNNABLE);
3532
3533 // The VM creates & returns objects of this class. Make sure it's initialized.
3534 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3535
3536 // The VM preresolves methods to these classes. Make sure that they get initialized
3537 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3538 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3539 call_initializeSystemClass(CHECK_0);
3540
3541 // get the Java runtime name after java.lang.System is initialized
3542 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3543 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3544
3545 // an instance of OutOfMemory exception has been allocated earlier
3546 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3547 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3548 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3549 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3550 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3551 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3552 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3553 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3554 }
3555
3556 // See : bugid 4211085.
3557 // Background : the static initializer of java.lang.Compiler tries to read
3558 // property"java.compiler" and read & write property "java.vm.info".
3559 // When a security manager is installed through the command line
3560 // option "-Djava.security.manager", the above properties are not
3561 // readable and the static initializer for java.lang.Compiler fails
3562 // resulting in a NoClassDefFoundError. This can happen in any
3563 // user code which calls methods in java.lang.Compiler.
3564 // Hack : the hack is to pre-load and initialize this class, so that only
3565 // system domains are on the stack when the properties are read.
3566 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3567 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3568 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3569 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3570 // Once that is done, we should remove this hack.
3571 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3572
3573 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3574 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3575 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3576 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3577 // This should also be taken out as soon as 4211383 gets fixed.
3578 reset_vm_info_property(CHECK_0);
3579
3580 quicken_jni_functions();
3581
3582 // Must be run after init_ft which initializes ft_enabled
3583 if (TRACE_INITIALIZE() != JNI_OK) {
3584 vm_exit_during_initialization("Failed to initialize tracing backend");
3585 }
3586
3587 // Set flag that basic initialization has completed. Used by exceptions and various
3588 // debug stuff, that does not work until all basic classes have been initialized.
3589 set_init_completed();
3590
3591 #ifndef USDT2
3592 HS_DTRACE_PROBE(hotspot, vm__init__end);
3593 #else /* USDT2 */
3594 HOTSPOT_VM_INIT_END();
3595 #endif /* USDT2 */
3596
3597 // record VM initialization completion time
3598 #if INCLUDE_MANAGEMENT
3599 Management::record_vm_init_completed();
3600 #endif // INCLUDE_MANAGEMENT
3601
3602 // Compute system loader. Note that this has to occur after set_init_completed, since
3603 // valid exceptions may be thrown in the process.
3604 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3605 // set_init_completed has just been called, causing exceptions not to be shortcut
3606 // anymore. We call vm_exit_during_initialization directly instead.
3607 SystemDictionary::compute_java_system_loader(THREAD);
3608 if (HAS_PENDING_EXCEPTION) {
3609 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3610 }
3611
3612 #if INCLUDE_ALL_GCS
3613 // Support for ConcurrentMarkSweep. This should be cleaned up
3614 // and better encapsulated. The ugly nested if test would go away
3615 // once things are properly refactored. XXX YSR
3616 if (UseConcMarkSweepGC || UseG1GC) {
3617 if (UseConcMarkSweepGC) {
3618 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3619 } else {
3620 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3621 }
3622 if (HAS_PENDING_EXCEPTION) {
3623 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3624 }
3625 }
3626 #endif // INCLUDE_ALL_GCS
3627
3628 // Always call even when there are not JVMTI environments yet, since environments
3629 // may be attached late and JVMTI must track phases of VM execution
3630 JvmtiExport::enter_live_phase();
3631
3632 // Signal Dispatcher needs to be started before VMInit event is posted
3633 os::signal_init();
3634
3635 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3636 if (!DisableAttachMechanism) {
3637 if (StartAttachListener || AttachListener::init_at_startup()) {
3638 AttachListener::init();
3639 }
3640 }
3641
3642 // Launch -Xrun agents
3643 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3644 // back-end can launch with -Xdebug -Xrunjdwp.
3645 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3646 create_vm_init_libraries();
3647 }
3648
3649 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3650 JvmtiExport::post_vm_initialized();
3651
3652 if (!TRACE_START()) {
3653 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3654 }
3655
3656 if (CleanChunkPoolAsync) {
3657 Chunk::start_chunk_pool_cleaner_task();
3658 }
3659
3660 // initialize compiler(s)
3661 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3662 CompileBroker::compilation_init();
3663 #endif
3664
3665 #if INCLUDE_MANAGEMENT
3666 Management::initialize(THREAD);
3667 #endif // INCLUDE_MANAGEMENT
3668
3669 if (HAS_PENDING_EXCEPTION) {
3670 // management agent fails to start possibly due to
3671 // configuration problem and is responsible for printing
3672 // stack trace if appropriate. Simply exit VM.
3673 vm_exit(1);
3674 }
3675
3676 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3677 if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3678 if (MemProfiling) MemProfiler::engage();
3679 StatSampler::engage();
3680 if (CheckJNICalls) JniPeriodicChecker::engage();
3681
3682 BiasedLocking::init();
3683
3684 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3685 call_postVMInitHook(THREAD);
3686 // The Java side of PostVMInitHook.run must deal with all
3687 // exceptions and provide means of diagnosis.
3688 if (HAS_PENDING_EXCEPTION) {
3689 CLEAR_PENDING_EXCEPTION;
3690 }
3691 }
3692
3693 {
3694 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3695 // Make sure the watcher thread can be started by WatcherThread::start()
3696 // or by dynamic enrollment.
3697 WatcherThread::make_startable();
3698 // Start up the WatcherThread if there are any periodic tasks
3699 // NOTE: All PeriodicTasks should be registered by now. If they
3700 // aren't, late joiners might appear to start slowly (we might
3701 // take a while to process their first tick).
3702 if (PeriodicTask::num_tasks() > 0) {
3703 WatcherThread::start();
3704 }
3705 }
3706
3707 // Give os specific code one last chance to start
3708 os::init_3();
3709
3710 create_vm_timer.end();
3711 #ifdef ASSERT
3712 _vm_complete = true;
3713 #endif
3714 return JNI_OK;
3715 }
3716
3717 // type for the Agent_OnLoad and JVM_OnLoad entry points
3718 extern "C" {
3719 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3720 }
3721 // Find a command line agent library and return its entry point for
3722 // -agentlib: -agentpath: -Xrun
3723 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3724 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3725 OnLoadEntry_t on_load_entry = NULL;
3726 void *library = agent->os_lib(); // check if we have looked it up before
3727
3728 if (library == NULL) {
3729 char buffer[JVM_MAXPATHLEN];
3730 char ebuf[1024];
3731 const char *name = agent->name();
3732 const char *msg = "Could not find agent library ";
3733
3734 if (agent->is_absolute_path()) {
3735 library = os::dll_load(name, ebuf, sizeof ebuf);
3736 if (library == NULL) {
3737 const char *sub_msg = " in absolute path, with error: ";
3738 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3739 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3740 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3741 // If we can't find the agent, exit.
3742 vm_exit_during_initialization(buf, NULL);
3743 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3744 }
3745 } else {
3746 // Try to load the agent from the standard dll directory
3747 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3748 name)) {
3749 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3750 }
3751 if (library == NULL) { // Try the local directory
3752 char ns[1] = {0};
3753 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3754 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3755 }
3756 if (library == NULL) {
3757 const char *sub_msg = " on the library path, with error: ";
3758 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3759 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3760 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3761 // If we can't find the agent, exit.
3762 vm_exit_during_initialization(buf, NULL);
3763 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3764 }
3765 }
3766 }
3767 agent->set_os_lib(library);
3768 }
3769
3770 // Find the OnLoad function.
3771 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3772 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index]));
3773 if (on_load_entry != NULL) break;
3774 }
3775 return on_load_entry;
3776 }
3777
3778 // Find the JVM_OnLoad entry point
3779 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3780 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3781 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3782 }
3783
3784 // Find the Agent_OnLoad entry point
3785 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3786 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3787 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3788 }
3789
3790 // For backwards compatibility with -Xrun
3791 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3792 // treated like -agentpath:
3793 // Must be called before agent libraries are created
3794 void Threads::convert_vm_init_libraries_to_agents() {
3795 AgentLibrary* agent;
3796 AgentLibrary* next;
3797
3798 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3799 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3800 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3801
3802 // If there is an JVM_OnLoad function it will get called later,
3803 // otherwise see if there is an Agent_OnLoad
3804 if (on_load_entry == NULL) {
3805 on_load_entry = lookup_agent_on_load(agent);
3806 if (on_load_entry != NULL) {
3807 // switch it to the agent list -- so that Agent_OnLoad will be called,
3808 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3809 Arguments::convert_library_to_agent(agent);
3810 } else {
3811 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3812 }
3813 }
3814 }
3815 }
3816
3817 // Create agents for -agentlib: -agentpath: and converted -Xrun
3818 // Invokes Agent_OnLoad
3819 // Called very early -- before JavaThreads exist
3820 void Threads::create_vm_init_agents() {
3821 extern struct JavaVM_ main_vm;
3822 AgentLibrary* agent;
3823
3824 JvmtiExport::enter_onload_phase();
3825
3826 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3827 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3828
3829 if (on_load_entry != NULL) {
3830 // Invoke the Agent_OnLoad function
3831 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3832 if (err != JNI_OK) {
3833 vm_exit_during_initialization("agent library failed to init", agent->name());
3834 }
3835 } else {
3836 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3837 }
3838 }
3839 JvmtiExport::enter_primordial_phase();
3840 }
3841
3842 extern "C" {
3843 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3844 }
3845
3846 void Threads::shutdown_vm_agents() {
3847 // Send any Agent_OnUnload notifications
3848 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3849 extern struct JavaVM_ main_vm;
3850 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3851
3852 // Find the Agent_OnUnload function.
3853 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3854 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3855 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3856
3857 // Invoke the Agent_OnUnload function
3858 if (unload_entry != NULL) {
3859 JavaThread* thread = JavaThread::current();
3860 ThreadToNativeFromVM ttn(thread);
3861 HandleMark hm(thread);
3862 (*unload_entry)(&main_vm);
3863 break;
3864 }
3865 }
3866 }
3867 }
3868
3869 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3870 // Invokes JVM_OnLoad
3871 void Threads::create_vm_init_libraries() {
3872 extern struct JavaVM_ main_vm;
3873 AgentLibrary* agent;
3874
3875 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3876 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3877
3878 if (on_load_entry != NULL) {
3879 // Invoke the JVM_OnLoad function
3880 JavaThread* thread = JavaThread::current();
3881 ThreadToNativeFromVM ttn(thread);
3882 HandleMark hm(thread);
3883 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3884 if (err != JNI_OK) {
3885 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3886 }
3887 } else {
3888 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3889 }
3890 }
3891 }
3892
3893 // Last thread running calls java.lang.Shutdown.shutdown()
3894 void JavaThread::invoke_shutdown_hooks() {
3895 HandleMark hm(this);
3896
3897 // We could get here with a pending exception, if so clear it now.
3898 if (this->has_pending_exception()) {
3899 this->clear_pending_exception();
3900 }
3901
3902 EXCEPTION_MARK;
3903 Klass* k =
3904 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3905 THREAD);
3906 if (k != NULL) {
3907 // SystemDictionary::resolve_or_null will return null if there was
3908 // an exception. If we cannot load the Shutdown class, just don't
3909 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3910 // and finalizers (if runFinalizersOnExit is set) won't be run.
3911 // Note that if a shutdown hook was registered or runFinalizersOnExit
3912 // was called, the Shutdown class would have already been loaded
3913 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3914 instanceKlassHandle shutdown_klass (THREAD, k);
3915 JavaValue result(T_VOID);
3916 JavaCalls::call_static(&result,
3917 shutdown_klass,
3918 vmSymbols::shutdown_method_name(),
3919 vmSymbols::void_method_signature(),
3920 THREAD);
3921 }
3922 CLEAR_PENDING_EXCEPTION;
3923 }
3924
3925 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3926 // the program falls off the end of main(). Another VM exit path is through
3927 // vm_exit() when the program calls System.exit() to return a value or when
3928 // there is a serious error in VM. The two shutdown paths are not exactly
3929 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3930 // and VM_Exit op at VM level.
3931 //
3932 // Shutdown sequence:
3933 // + Shutdown native memory tracking if it is on
3934 // + Wait until we are the last non-daemon thread to execute
3935 // <-- every thing is still working at this moment -->
3936 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3937 // shutdown hooks, run finalizers if finalization-on-exit
3938 // + Call before_exit(), prepare for VM exit
3939 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3940 // currently the only user of this mechanism is File.deleteOnExit())
3941 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3942 // post thread end and vm death events to JVMTI,
3943 // stop signal thread
3944 // + Call JavaThread::exit(), it will:
3945 // > release JNI handle blocks, remove stack guard pages
3946 // > remove this thread from Threads list
3947 // <-- no more Java code from this thread after this point -->
3948 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3949 // the compiler threads at safepoint
3950 // <-- do not use anything that could get blocked by Safepoint -->
3951 // + Disable tracing at JNI/JVM barriers
3952 // + Set _vm_exited flag for threads that are still running native code
3953 // + Delete this thread
3954 // + Call exit_globals()
3955 // > deletes tty
3956 // > deletes PerfMemory resources
3957 // + Return to caller
3958
3959 bool Threads::destroy_vm() {
3960 JavaThread* thread = JavaThread::current();
3961
3962 #ifdef ASSERT
3963 _vm_complete = false;
3964 #endif
3965 // Wait until we are the last non-daemon thread to execute
3966 { MutexLocker nu(Threads_lock);
3967 while (Threads::number_of_non_daemon_threads() > 1 )
3968 // This wait should make safepoint checks, wait without a timeout,
3969 // and wait as a suspend-equivalent condition.
3970 //
3971 // Note: If the FlatProfiler is running and this thread is waiting
3972 // for another non-daemon thread to finish, then the FlatProfiler
3973 // is waiting for the external suspend request on this thread to
3974 // complete. wait_for_ext_suspend_completion() will eventually
3975 // timeout, but that takes time. Making this wait a suspend-
3976 // equivalent condition solves that timeout problem.
3977 //
3978 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3979 Mutex::_as_suspend_equivalent_flag);
3980 }
3981
3982 // Hang forever on exit if we are reporting an error.
3983 if (ShowMessageBoxOnError && is_error_reported()) {
3984 os::infinite_sleep();
3985 }
3986 os::wait_for_keypress_at_exit();
3987
3988 if (JDK_Version::is_jdk12x_version()) {
3989 // We are the last thread running, so check if finalizers should be run.
3990 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3991 HandleMark rm(thread);
3992 Universe::run_finalizers_on_exit();
3993 } else {
3994 // run Java level shutdown hooks
3995 thread->invoke_shutdown_hooks();
3996 }
3997
3998 before_exit(thread);
3999
4000 thread->exit(true);
4001
4002 // Stop VM thread.
4003 {
4004 // 4945125 The vm thread comes to a safepoint during exit.
4005 // GC vm_operations can get caught at the safepoint, and the
4006 // heap is unparseable if they are caught. Grab the Heap_lock
4007 // to prevent this. The GC vm_operations will not be able to
4008 // queue until after the vm thread is dead.
4009 // After this point, we'll never emerge out of the safepoint before
4010 // the VM exits, so concurrent GC threads do not need to be explicitly
4011 // stopped; they remain inactive until the process exits.
4012 // Note: some concurrent G1 threads may be running during a safepoint,
4013 // but these will not be accessing the heap, just some G1-specific side
4014 // data structures that are not accessed by any other threads but them
4015 // after this point in a terminal safepoint.
4016
4017 MutexLocker ml(Heap_lock);
4018
4019 VMThread::wait_for_vm_thread_exit();
4020 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4021 VMThread::destroy();
4022 }
4023
4024 // clean up ideal graph printers
4025 #if defined(COMPILER2) && !defined(PRODUCT)
4026 IdealGraphPrinter::clean_up();
4027 #endif
4028
4029 // Now, all Java threads are gone except daemon threads. Daemon threads
4030 // running Java code or in VM are stopped by the Safepoint. However,
4031 // daemon threads executing native code are still running. But they
4032 // will be stopped at native=>Java/VM barriers. Note that we can't
4033 // simply kill or suspend them, as it is inherently deadlock-prone.
4034
4035 #ifndef PRODUCT
4036 // disable function tracing at JNI/JVM barriers
4037 TraceJNICalls = false;
4038 TraceJVMCalls = false;
4039 TraceRuntimeCalls = false;
4040 #endif
4041
4042 VM_Exit::set_vm_exited();
4043
4044 notify_vm_shutdown();
4045
4046 delete thread;
4047
4048 // exit_globals() will delete tty
4049 exit_globals();
4050
4051 return true;
4052 }
4053
4054
4055 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4056 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4057 return is_supported_jni_version(version);
4058 }
4059
4060
4061 jboolean Threads::is_supported_jni_version(jint version) {
4062 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4063 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4064 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4065 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4066 return JNI_FALSE;
4067 }
4068
4069
4070 void Threads::add(JavaThread* p, bool force_daemon) {
4071 // The threads lock must be owned at this point
4072 assert_locked_or_safepoint(Threads_lock);
4073
4074 // See the comment for this method in thread.hpp for its purpose and
4075 // why it is called here.
4076 p->initialize_queues();
4077 p->set_next(_thread_list);
4078 _thread_list = p;
4079 _number_of_threads++;
4080 oop threadObj = p->threadObj();
4081 bool daemon = true;
4082 // Bootstrapping problem: threadObj can be null for initial
4083 // JavaThread (or for threads attached via JNI)
4084 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4085 _number_of_non_daemon_threads++;
4086 daemon = false;
4087 }
4088
4089 p->set_safepoint_visible(true);
4090
4091 ThreadService::add_thread(p, daemon);
4092
4093 // Possible GC point.
4094 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4095 }
4096
4097 void Threads::remove(JavaThread* p) {
4098 // Extra scope needed for Thread_lock, so we can check
4099 // that we do not remove thread without safepoint code notice
4100 { MutexLocker ml(Threads_lock);
4101
4102 assert(includes(p), "p must be present");
4103
4104 JavaThread* current = _thread_list;
4105 JavaThread* prev = NULL;
4106
4107 while (current != p) {
4108 prev = current;
4109 current = current->next();
4110 }
4111
4112 if (prev) {
4113 prev->set_next(current->next());
4114 } else {
4115 _thread_list = p->next();
4116 }
4117 _number_of_threads--;
4118 oop threadObj = p->threadObj();
4119 bool daemon = true;
4120 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4121 _number_of_non_daemon_threads--;
4122 daemon = false;
4123
4124 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4125 // on destroy_vm will wake up.
4126 if (number_of_non_daemon_threads() == 1)
4127 Threads_lock->notify_all();
4128 }
4129 ThreadService::remove_thread(p, daemon);
4130
4131 // Make sure that safepoint code disregard this thread. This is needed since
4132 // the thread might mess around with locks after this point. This can cause it
4133 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4134 // of this thread since it is removed from the queue.
4135 p->set_terminated_value();
4136
4137 // Now, this thread is not visible to safepoint
4138 p->set_safepoint_visible(false);
4139 // once the thread becomes safepoint invisible, we can not use its per-thread
4140 // recorder. And Threads::do_threads() no longer walks this thread, so we have
4141 // to release its per-thread recorder here.
4142 MemTracker::thread_exiting(p);
4143 } // unlock Threads_lock
4144
4145 // Since Events::log uses a lock, we grab it outside the Threads_lock
4146 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4147 }
4148
4149 // Threads_lock must be held when this is called (or must be called during a safepoint)
4150 bool Threads::includes(JavaThread* p) {
4151 assert(Threads_lock->is_locked(), "sanity check");
4152 ALL_JAVA_THREADS(q) {
4153 if (q == p ) {
4154 return true;
4155 }
4156 }
4157 return false;
4158 }
4159
4160 // Operations on the Threads list for GC. These are not explicitly locked,
4161 // but the garbage collector must provide a safe context for them to run.
4162 // In particular, these things should never be called when the Threads_lock
4163 // is held by some other thread. (Note: the Safepoint abstraction also
4164 // uses the Threads_lock to gurantee this property. It also makes sure that
4165 // all threads gets blocked when exiting or starting).
4166
4167 void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4168 ALL_JAVA_THREADS(p) {
4169 p->oops_do(f, cld_f, cf);
4170 }
4171 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4172 }
4173
4174 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) {
4175 // Introduce a mechanism allowing parallel threads to claim threads as
4176 // root groups. Overhead should be small enough to use all the time,
4177 // even in sequential code.
4178 SharedHeap* sh = SharedHeap::heap();
4179 // Cannot yet substitute active_workers for n_par_threads
4180 // because of G1CollectedHeap::verify() use of
4181 // SharedHeap::process_strong_roots(). n_par_threads == 0 will
4182 // turn off parallelism in process_strong_roots while active_workers
4183 // is being used for parallelism elsewhere.
4184 bool is_par = sh->n_par_threads() > 0;
4185 assert(!is_par ||
4186 (SharedHeap::heap()->n_par_threads() ==
4187 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4188 int cp = SharedHeap::heap()->strong_roots_parity();
4189 ALL_JAVA_THREADS(p) {
4190 if (p->claim_oops_do(is_par, cp)) {
4191 p->oops_do(f, cld_f, cf);
4192 }
4193 }
4194 VMThread* vmt = VMThread::vm_thread();
4195 if (vmt->claim_oops_do(is_par, cp)) {
4196 vmt->oops_do(f, cld_f, cf);
4197 }
4198 }
4199
4200 #if INCLUDE_ALL_GCS
4201 // Used by ParallelScavenge
4202 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4203 ALL_JAVA_THREADS(p) {
4204 q->enqueue(new ThreadRootsTask(p));
4205 }
4206 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4207 }
4208
4209 // Used by Parallel Old
4210 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4211 ALL_JAVA_THREADS(p) {
4212 q->enqueue(new ThreadRootsMarkingTask(p));
4213 }
4214 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4215 }
4216 #endif // INCLUDE_ALL_GCS
4217
4218 void Threads::nmethods_do(CodeBlobClosure* cf) {
4219 ALL_JAVA_THREADS(p) {
4220 p->nmethods_do(cf);
4221 }
4222 VMThread::vm_thread()->nmethods_do(cf);
4223 }
4224
4225 void Threads::metadata_do(void f(Metadata*)) {
4226 ALL_JAVA_THREADS(p) {
4227 p->metadata_do(f);
4228 }
4229 }
4230
4231 void Threads::gc_epilogue() {
4232 ALL_JAVA_THREADS(p) {
4233 p->gc_epilogue();
4234 }
4235 }
4236
4237 void Threads::gc_prologue() {
4238 ALL_JAVA_THREADS(p) {
4239 p->gc_prologue();
4240 }
4241 }
4242
4243 void Threads::deoptimized_wrt_marked_nmethods() {
4244 ALL_JAVA_THREADS(p) {
4245 p->deoptimized_wrt_marked_nmethods();
4246 }
4247 }
4248
4249
4250 // Get count Java threads that are waiting to enter the specified monitor.
4251 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4252 address monitor, bool doLock) {
4253 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4254 "must grab Threads_lock or be at safepoint");
4255 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4256
4257 int i = 0;
4258 {
4259 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4260 ALL_JAVA_THREADS(p) {
4261 if (p->is_Compiler_thread()) continue;
4262
4263 address pending = (address)p->current_pending_monitor();
4264 if (pending == monitor) { // found a match
4265 if (i < count) result->append(p); // save the first count matches
4266 i++;
4267 }
4268 }
4269 }
4270 return result;
4271 }
4272
4273
4274 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4275 assert(doLock ||
4276 Threads_lock->owned_by_self() ||
4277 SafepointSynchronize::is_at_safepoint(),
4278 "must grab Threads_lock or be at safepoint");
4279
4280 // NULL owner means not locked so we can skip the search
4281 if (owner == NULL) return NULL;
4282
4283 {
4284 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4285 ALL_JAVA_THREADS(p) {
4286 // first, see if owner is the address of a Java thread
4287 if (owner == (address)p) return p;
4288 }
4289 }
4290 // Cannot assert on lack of success here since this function may be
4291 // used by code that is trying to report useful problem information
4292 // like deadlock detection.
4293 if (UseHeavyMonitors) return NULL;
4294
4295 //
4296 // If we didn't find a matching Java thread and we didn't force use of
4297 // heavyweight monitors, then the owner is the stack address of the
4298 // Lock Word in the owning Java thread's stack.
4299 //
4300 JavaThread* the_owner = NULL;
4301 {
4302 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4303 ALL_JAVA_THREADS(q) {
4304 if (q->is_lock_owned(owner)) {
4305 the_owner = q;
4306 break;
4307 }
4308 }
4309 }
4310 // cannot assert on lack of success here; see above comment
4311 return the_owner;
4312 }
4313
4314 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4315 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4316 char buf[32];
4317 st->print_cr(os::local_time_string(buf, sizeof(buf)));
4318
4319 st->print_cr("Full thread dump %s (%s %s):",
4320 Abstract_VM_Version::vm_name(),
4321 Abstract_VM_Version::vm_release(),
4322 Abstract_VM_Version::vm_info_string()
4323 );
4324 st->cr();
4325
4326 #if INCLUDE_ALL_GCS
4327 // Dump concurrent locks
4328 ConcurrentLocksDump concurrent_locks;
4329 if (print_concurrent_locks) {
4330 concurrent_locks.dump_at_safepoint();
4331 }
4332 #endif // INCLUDE_ALL_GCS
4333
4334 ALL_JAVA_THREADS(p) {
4335 ResourceMark rm;
4336 p->print_on(st);
4337 if (print_stacks) {
4338 if (internal_format) {
4339 p->trace_stack();
4340 } else {
4341 p->print_stack_on(st);
4342 }
4343 }
4344 st->cr();
4345 #if INCLUDE_ALL_GCS
4346 if (print_concurrent_locks) {
4347 concurrent_locks.print_locks_on(p, st);
4348 }
4349 #endif // INCLUDE_ALL_GCS
4350 }
4351
4352 VMThread::vm_thread()->print_on(st);
4353 st->cr();
4354 Universe::heap()->print_gc_threads_on(st);
4355 WatcherThread* wt = WatcherThread::watcher_thread();
4356 if (wt != NULL) {
4357 wt->print_on(st);
4358 st->cr();
4359 }
4360 CompileBroker::print_compiler_threads_on(st);
4361 st->flush();
4362 }
4363
4364 // Threads::print_on_error() is called by fatal error handler. It's possible
4365 // that VM is not at safepoint and/or current thread is inside signal handler.
4366 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4367 // memory (even in resource area), it might deadlock the error handler.
4368 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4369 bool found_current = false;
4370 st->print_cr("Java Threads: ( => current thread )");
4371 ALL_JAVA_THREADS(thread) {
4372 bool is_current = (current == thread);
4373 found_current = found_current || is_current;
4374
4375 st->print("%s", is_current ? "=>" : " ");
4376
4377 st->print(PTR_FORMAT, thread);
4378 st->print(" ");
4379 thread->print_on_error(st, buf, buflen);
4380 st->cr();
4381 }
4382 st->cr();
4383
4384 st->print_cr("Other Threads:");
4385 if (VMThread::vm_thread()) {
4386 bool is_current = (current == VMThread::vm_thread());
4387 found_current = found_current || is_current;
4388 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4389
4390 st->print(PTR_FORMAT, VMThread::vm_thread());
4391 st->print(" ");
4392 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4393 st->cr();
4394 }
4395 WatcherThread* wt = WatcherThread::watcher_thread();
4396 if (wt != NULL) {
4397 bool is_current = (current == wt);
4398 found_current = found_current || is_current;
4399 st->print("%s", is_current ? "=>" : " ");
4400
4401 st->print(PTR_FORMAT, wt);
4402 st->print(" ");
4403 wt->print_on_error(st, buf, buflen);
4404 st->cr();
4405 }
4406 if (!found_current) {
4407 st->cr();
4408 st->print("=>" PTR_FORMAT " (exited) ", current);
4409 current->print_on_error(st, buf, buflen);
4410 st->cr();
4411 }
4412 }
4413
4414 // Internal SpinLock and Mutex
4415 // Based on ParkEvent
4416
4417 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4418 //
4419 // We employ SpinLocks _only for low-contention, fixed-length
4420 // short-duration critical sections where we're concerned
4421 // about native mutex_t or HotSpot Mutex:: latency.
4422 // The mux construct provides a spin-then-block mutual exclusion
4423 // mechanism.
4424 //
4425 // Testing has shown that contention on the ListLock guarding gFreeList
4426 // is common. If we implement ListLock as a simple SpinLock it's common
4427 // for the JVM to devolve to yielding with little progress. This is true
4428 // despite the fact that the critical sections protected by ListLock are
4429 // extremely short.
4430 //
4431 // TODO-FIXME: ListLock should be of type SpinLock.
4432 // We should make this a 1st-class type, integrated into the lock
4433 // hierarchy as leaf-locks. Critically, the SpinLock structure
4434 // should have sufficient padding to avoid false-sharing and excessive
4435 // cache-coherency traffic.
4436
4437
4438 typedef volatile int SpinLockT ;
4439
4440 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4441 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4442 return ; // normal fast-path return
4443 }
4444
4445 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4446 TEVENT (SpinAcquire - ctx) ;
4447 int ctr = 0 ;
4448 int Yields = 0 ;
4449 for (;;) {
4450 while (*adr != 0) {
4451 ++ctr ;
4452 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4453 if (Yields > 5) {
4454 // Consider using a simple NakedSleep() instead.
4455 // Then SpinAcquire could be called by non-JVM threads
4456 Thread::current()->_ParkEvent->park(1) ;
4457 } else {
4458 os::NakedYield() ;
4459 ++Yields ;
4460 }
4461 } else {
4462 SpinPause() ;
4463 }
4464 }
4465 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4466 }
4467 }
4468
4469 void Thread::SpinRelease (volatile int * adr) {
4470 assert (*adr != 0, "invariant") ;
4471 OrderAccess::fence() ; // guarantee at least release consistency.
4472 // Roach-motel semantics.
4473 // It's safe if subsequent LDs and STs float "up" into the critical section,
4474 // but prior LDs and STs within the critical section can't be allowed
4475 // to reorder or float past the ST that releases the lock.
4476 *adr = 0 ;
4477 }
4478
4479 // muxAcquire and muxRelease:
4480 //
4481 // * muxAcquire and muxRelease support a single-word lock-word construct.
4482 // The LSB of the word is set IFF the lock is held.
4483 // The remainder of the word points to the head of a singly-linked list
4484 // of threads blocked on the lock.
4485 //
4486 // * The current implementation of muxAcquire-muxRelease uses its own
4487 // dedicated Thread._MuxEvent instance. If we're interested in
4488 // minimizing the peak number of extant ParkEvent instances then
4489 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4490 // as certain invariants were satisfied. Specifically, care would need
4491 // to be taken with regards to consuming unpark() "permits".
4492 // A safe rule of thumb is that a thread would never call muxAcquire()
4493 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4494 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4495 // consume an unpark() permit intended for monitorenter, for instance.
4496 // One way around this would be to widen the restricted-range semaphore
4497 // implemented in park(). Another alternative would be to provide
4498 // multiple instances of the PlatformEvent() for each thread. One
4499 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4500 //
4501 // * Usage:
4502 // -- Only as leaf locks
4503 // -- for short-term locking only as muxAcquire does not perform
4504 // thread state transitions.
4505 //
4506 // Alternatives:
4507 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4508 // but with parking or spin-then-park instead of pure spinning.
4509 // * Use Taura-Oyama-Yonenzawa locks.
4510 // * It's possible to construct a 1-0 lock if we encode the lockword as
4511 // (List,LockByte). Acquire will CAS the full lockword while Release
4512 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4513 // acquiring threads use timers (ParkTimed) to detect and recover from
4514 // the stranding window. Thread/Node structures must be aligned on 256-byte
4515 // boundaries by using placement-new.
4516 // * Augment MCS with advisory back-link fields maintained with CAS().
4517 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4518 // The validity of the backlinks must be ratified before we trust the value.
4519 // If the backlinks are invalid the exiting thread must back-track through the
4520 // the forward links, which are always trustworthy.
4521 // * Add a successor indication. The LockWord is currently encoded as
4522 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4523 // to provide the usual futile-wakeup optimization.
4524 // See RTStt for details.
4525 // * Consider schedctl.sc_nopreempt to cover the critical section.
4526 //
4527
4528
4529 typedef volatile intptr_t MutexT ; // Mux Lock-word
4530 enum MuxBits { LOCKBIT = 1 } ;
4531
4532 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4533 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4534 if (w == 0) return ;
4535 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4536 return ;
4537 }
4538
4539 TEVENT (muxAcquire - Contention) ;
4540 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4541 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4542 for (;;) {
4543 int its = (os::is_MP() ? 100 : 0) + 1 ;
4544
4545 // Optional spin phase: spin-then-park strategy
4546 while (--its >= 0) {
4547 w = *Lock ;
4548 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4549 return ;
4550 }
4551 }
4552
4553 Self->reset() ;
4554 Self->OnList = intptr_t(Lock) ;
4555 // The following fence() isn't _strictly necessary as the subsequent
4556 // CAS() both serializes execution and ratifies the fetched *Lock value.
4557 OrderAccess::fence();
4558 for (;;) {
4559 w = *Lock ;
4560 if ((w & LOCKBIT) == 0) {
4561 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4562 Self->OnList = 0 ; // hygiene - allows stronger asserts
4563 return ;
4564 }
4565 continue ; // Interference -- *Lock changed -- Just retry
4566 }
4567 assert (w & LOCKBIT, "invariant") ;
4568 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4569 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4570 }
4571
4572 while (Self->OnList != 0) {
4573 Self->park() ;
4574 }
4575 }
4576 }
4577
4578 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4579 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4580 if (w == 0) return ;
4581 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4582 return ;
4583 }
4584
4585 TEVENT (muxAcquire - Contention) ;
4586 ParkEvent * ReleaseAfter = NULL ;
4587 if (ev == NULL) {
4588 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4589 }
4590 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4591 for (;;) {
4592 guarantee (ev->OnList == 0, "invariant") ;
4593 int its = (os::is_MP() ? 100 : 0) + 1 ;
4594
4595 // Optional spin phase: spin-then-park strategy
4596 while (--its >= 0) {
4597 w = *Lock ;
4598 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4599 if (ReleaseAfter != NULL) {
4600 ParkEvent::Release (ReleaseAfter) ;
4601 }
4602 return ;
4603 }
4604 }
4605
4606 ev->reset() ;
4607 ev->OnList = intptr_t(Lock) ;
4608 // The following fence() isn't _strictly necessary as the subsequent
4609 // CAS() both serializes execution and ratifies the fetched *Lock value.
4610 OrderAccess::fence();
4611 for (;;) {
4612 w = *Lock ;
4613 if ((w & LOCKBIT) == 0) {
4614 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4615 ev->OnList = 0 ;
4616 // We call ::Release while holding the outer lock, thus
4617 // artificially lengthening the critical section.
4618 // Consider deferring the ::Release() until the subsequent unlock(),
4619 // after we've dropped the outer lock.
4620 if (ReleaseAfter != NULL) {
4621 ParkEvent::Release (ReleaseAfter) ;
4622 }
4623 return ;
4624 }
4625 continue ; // Interference -- *Lock changed -- Just retry
4626 }
4627 assert (w & LOCKBIT, "invariant") ;
4628 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4629 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4630 }
4631
4632 while (ev->OnList != 0) {
4633 ev->park() ;
4634 }
4635 }
4636 }
4637
4638 // Release() must extract a successor from the list and then wake that thread.
4639 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4640 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4641 // Release() would :
4642 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4643 // (B) Extract a successor from the private list "in-hand"
4644 // (C) attempt to CAS() the residual back into *Lock over null.
4645 // If there were any newly arrived threads and the CAS() would fail.
4646 // In that case Release() would detach the RATs, re-merge the list in-hand
4647 // with the RATs and repeat as needed. Alternately, Release() might
4648 // detach and extract a successor, but then pass the residual list to the wakee.
4649 // The wakee would be responsible for reattaching and remerging before it
4650 // competed for the lock.
4651 //
4652 // Both "pop" and DMR are immune from ABA corruption -- there can be
4653 // multiple concurrent pushers, but only one popper or detacher.
4654 // This implementation pops from the head of the list. This is unfair,
4655 // but tends to provide excellent throughput as hot threads remain hot.
4656 // (We wake recently run threads first).
4657
4658 void Thread::muxRelease (volatile intptr_t * Lock) {
4659 for (;;) {
4660 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4661 assert (w & LOCKBIT, "invariant") ;
4662 if (w == LOCKBIT) return ;
4663 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4664 assert (List != NULL, "invariant") ;
4665 assert (List->OnList == intptr_t(Lock), "invariant") ;
4666 ParkEvent * nxt = List->ListNext ;
4667
4668 // The following CAS() releases the lock and pops the head element.
4669 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4670 continue ;
4671 }
4672 List->OnList = 0 ;
4673 OrderAccess::fence() ;
4674 List->unpark () ;
4675 return ;
4676 }
4677 }
4678
4679
4680 void Threads::verify() {
4681 ALL_JAVA_THREADS(p) {
4682 p->verify();
4683 }
4684 VMThread* thread = VMThread::vm_thread();
4685 if (thread != NULL) thread->verify();
4686 }