1 /*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/javaClasses.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/codeCacheExtensions.hpp"
32 #include "code/scopeDesc.hpp"
33 #include "compiler/compileBroker.hpp"
34 #include "gc/shared/gcId.hpp"
35 #include "gc/shared/gcLocker.inline.hpp"
36 #include "gc/shared/workgroup.hpp"
37 #include "interpreter/interpreter.hpp"
38 #include "interpreter/linkResolver.hpp"
39 #include "interpreter/oopMapCache.hpp"
40 #include "jvmtifiles/jvmtiEnv.hpp"
41 #include "logging/logConfiguration.hpp"
42 #include "memory/metaspaceShared.hpp"
43 #include "memory/oopFactory.hpp"
44 #include "memory/universe.inline.hpp"
45 #include "oops/instanceKlass.hpp"
46 #include "oops/objArrayOop.hpp"
47 #include "oops/oop.inline.hpp"
48 #include "oops/symbol.hpp"
49 #include "oops/verifyOopClosure.hpp"
50 #include "prims/jvm_misc.hpp"
51 #include "prims/jvmtiExport.hpp"
52 #include "prims/jvmtiThreadState.hpp"
53 #include "prims/privilegedStack.hpp"
54 #include "runtime/arguments.hpp"
55 #include "runtime/atomic.inline.hpp"
56 #include "runtime/biasedLocking.hpp"
57 #include "runtime/commandLineFlagConstraintList.hpp"
58 #include "runtime/commandLineFlagRangeList.hpp"
59 #include "runtime/deoptimization.hpp"
60 #include "runtime/fprofiler.hpp"
61 #include "runtime/frame.inline.hpp"
62 #include "runtime/globals.hpp"
63 #include "runtime/init.hpp"
64 #include "runtime/interfaceSupport.hpp"
65 #include "runtime/java.hpp"
66 #include "runtime/javaCalls.hpp"
67 #include "runtime/jniPeriodicChecker.hpp"
68 #include "runtime/memprofiler.hpp"
69 #include "runtime/mutexLocker.hpp"
70 #include "runtime/objectMonitor.hpp"
71 #include "runtime/orderAccess.inline.hpp"
72 #include "runtime/osThread.hpp"
73 #include "runtime/safepoint.hpp"
74 #include "runtime/sharedRuntime.hpp"
75 #include "runtime/statSampler.hpp"
76 #include "runtime/stubRoutines.hpp"
77 #include "runtime/sweeper.hpp"
78 #include "runtime/task.hpp"
79 #include "runtime/thread.inline.hpp"
80 #include "runtime/threadCritical.hpp"
81 #include "runtime/threadLocalStorage.hpp"
82 #include "runtime/vframe.hpp"
83 #include "runtime/vframeArray.hpp"
84 #include "runtime/vframe_hp.hpp"
85 #include "runtime/vmThread.hpp"
86 #include "runtime/vm_operations.hpp"
87 #include "runtime/vm_version.hpp"
88 #include "services/attachListener.hpp"
89 #include "services/management.hpp"
90 #include "services/memTracker.hpp"
91 #include "services/threadService.hpp"
92 #include "trace/traceMacros.hpp"
93 #include "trace/tracing.hpp"
94 #include "utilities/defaultStream.hpp"
95 #include "utilities/dtrace.hpp"
96 #include "utilities/events.hpp"
97 #include "utilities/macros.hpp"
98 #include "utilities/preserveException.hpp"
99 #if INCLUDE_ALL_GCS
100 #include "gc/cms/concurrentMarkSweepThread.hpp"
101 #include "gc/g1/concurrentMarkThread.inline.hpp"
102 #include "gc/parallel/pcTasks.hpp"
103 #endif // INCLUDE_ALL_GCS
104 #ifdef COMPILER1
105 #include "c1/c1_Compiler.hpp"
106 #endif
107 #ifdef COMPILER2
108 #include "opto/c2compiler.hpp"
109 #include "opto/idealGraphPrinter.hpp"
110 #endif
111 #if INCLUDE_RTM_OPT
112 #include "runtime/rtmLocking.hpp"
113 #endif
114
115 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
116
117 #ifdef DTRACE_ENABLED
118
119 // Only bother with this argument setup if dtrace is available
120
121 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
122 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
123
124 #define DTRACE_THREAD_PROBE(probe, javathread) \
125 { \
126 ResourceMark rm(this); \
127 int len = 0; \
128 const char* name = (javathread)->get_thread_name(); \
129 len = strlen(name); \
130 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
131 (char *) name, len, \
132 java_lang_Thread::thread_id((javathread)->threadObj()), \
133 (uintptr_t) (javathread)->osthread()->thread_id(), \
134 java_lang_Thread::is_daemon((javathread)->threadObj())); \
135 }
136
137 #else // ndef DTRACE_ENABLED
138
139 #define DTRACE_THREAD_PROBE(probe, javathread)
140
141 #endif // ndef DTRACE_ENABLED
142
143
144 // Class hierarchy
145 // - Thread
146 // - VMThread
147 // - WatcherThread
148 // - ConcurrentMarkSweepThread
149 // - JavaThread
150 // - CompilerThread
151
152 // ======= Thread ========
153 // Support for forcing alignment of thread objects for biased locking
154 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
155 if (UseBiasedLocking) {
156 const int alignment = markOopDesc::biased_lock_alignment;
157 size_t aligned_size = size + (alignment - sizeof(intptr_t));
158 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
159 : AllocateHeap(aligned_size, flags, CURRENT_PC,
160 AllocFailStrategy::RETURN_NULL);
161 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
162 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
163 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
164 "JavaThread alignment code overflowed allocated storage");
165 if (TraceBiasedLocking) {
166 if (aligned_addr != real_malloc_addr) {
167 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
168 real_malloc_addr, aligned_addr);
169 }
170 }
171 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
172 return aligned_addr;
173 } else {
174 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
175 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
176 }
177 }
178
179 void Thread::operator delete(void* p) {
180 if (UseBiasedLocking) {
181 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
182 FreeHeap(real_malloc_addr);
183 } else {
184 FreeHeap(p);
185 }
186 }
187
188
189 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
190 // JavaThread
191
192
193 Thread::Thread() {
194 // stack and get_thread
195 set_stack_base(NULL);
196 set_stack_size(0);
197 set_self_raw_id(0);
198 set_lgrp_id(-1);
199 DEBUG_ONLY(clear_suspendible_thread();)
200
201 // allocated data structures
202 set_osthread(NULL);
203 set_resource_area(new (mtThread)ResourceArea());
204 DEBUG_ONLY(_current_resource_mark = NULL;)
205 set_handle_area(new (mtThread) HandleArea(NULL));
206 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
207 set_active_handles(NULL);
208 set_free_handle_block(NULL);
209 set_last_handle_mark(NULL);
210
211 // This initial value ==> never claimed.
212 _oops_do_parity = 0;
213
214 // the handle mark links itself to last_handle_mark
215 new HandleMark(this);
216
217 // plain initialization
218 debug_only(_owned_locks = NULL;)
219 debug_only(_allow_allocation_count = 0;)
220 NOT_PRODUCT(_allow_safepoint_count = 0;)
221 NOT_PRODUCT(_skip_gcalot = false;)
222 _jvmti_env_iteration_count = 0;
223 set_allocated_bytes(0);
224 _gc_id = GCId::undefined();
225 _vm_operation_started_count = 0;
226 _vm_operation_completed_count = 0;
227 _current_pending_monitor = NULL;
228 _current_pending_monitor_is_from_java = true;
229 _current_waiting_monitor = NULL;
230 _num_nested_signal = 0;
231 omFreeList = NULL;
232 omFreeCount = 0;
233 omFreeProvision = 32;
234 omInUseList = NULL;
235 omInUseCount = 0;
236
237 #ifdef ASSERT
238 _visited_for_critical_count = false;
239 #endif
240
241 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
242 Monitor::_safepoint_check_sometimes);
243 _suspend_flags = 0;
244
245 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
246 _hashStateX = os::random();
247 _hashStateY = 842502087;
248 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
249 _hashStateW = 273326509;
250
251 _OnTrap = 0;
252 _schedctl = NULL;
253 _Stalled = 0;
254 _TypeTag = 0x2BAD;
255
256 // Many of the following fields are effectively final - immutable
257 // Note that nascent threads can't use the Native Monitor-Mutex
258 // construct until the _MutexEvent is initialized ...
259 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
260 // we might instead use a stack of ParkEvents that we could provision on-demand.
261 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
262 // and ::Release()
263 _ParkEvent = ParkEvent::Allocate(this);
264 _SleepEvent = ParkEvent::Allocate(this);
265 _MutexEvent = ParkEvent::Allocate(this);
266 _MuxEvent = ParkEvent::Allocate(this);
267
268 #ifdef CHECK_UNHANDLED_OOPS
269 if (CheckUnhandledOops) {
270 _unhandled_oops = new UnhandledOops(this);
271 }
272 #endif // CHECK_UNHANDLED_OOPS
273 #ifdef ASSERT
274 if (UseBiasedLocking) {
275 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
276 assert(this == _real_malloc_address ||
277 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
278 "bug in forced alignment of thread objects");
279 }
280 #endif // ASSERT
281 }
282
283 // Non-inlined version to be used where thread.inline.hpp shouldn't be included.
284 Thread* Thread::current_noinline() {
285 return Thread::current();
286 }
287
288 void Thread::initialize_thread_local_storage() {
289 // Note: Make sure this method only calls
290 // non-blocking operations. Otherwise, it might not work
291 // with the thread-startup/safepoint interaction.
292
293 // During Java thread startup, safepoint code should allow this
294 // method to complete because it may need to allocate memory to
295 // store information for the new thread.
296
297 // initialize structure dependent on thread local storage
298 ThreadLocalStorage::set_thread(this);
299 }
300
301 void Thread::record_stack_base_and_size() {
302 set_stack_base(os::current_stack_base());
303 set_stack_size(os::current_stack_size());
304 if (is_Java_thread()) {
305 ((JavaThread*) this)->set_stack_overflow_limit();
306 }
307 // CR 7190089: on Solaris, primordial thread's stack is adjusted
308 // in initialize_thread(). Without the adjustment, stack size is
309 // incorrect if stack is set to unlimited (ulimit -s unlimited).
310 // So far, only Solaris has real implementation of initialize_thread().
311 //
312 // set up any platform-specific state.
313 os::initialize_thread(this);
314
315 #if INCLUDE_NMT
316 // record thread's native stack, stack grows downward
317 address stack_low_addr = stack_base() - stack_size();
318 MemTracker::record_thread_stack(stack_low_addr, stack_size());
319 #endif // INCLUDE_NMT
320 }
321
322
323 Thread::~Thread() {
324 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
325 ObjectSynchronizer::omFlush(this);
326
327 EVENT_THREAD_DESTRUCT(this);
328
329 // stack_base can be NULL if the thread is never started or exited before
330 // record_stack_base_and_size called. Although, we would like to ensure
331 // that all started threads do call record_stack_base_and_size(), there is
332 // not proper way to enforce that.
333 #if INCLUDE_NMT
334 if (_stack_base != NULL) {
335 address low_stack_addr = stack_base() - stack_size();
336 MemTracker::release_thread_stack(low_stack_addr, stack_size());
337 #ifdef ASSERT
338 set_stack_base(NULL);
339 #endif
340 }
341 #endif // INCLUDE_NMT
342
343 // deallocate data structures
344 delete resource_area();
345 // since the handle marks are using the handle area, we have to deallocated the root
346 // handle mark before deallocating the thread's handle area,
347 assert(last_handle_mark() != NULL, "check we have an element");
348 delete last_handle_mark();
349 assert(last_handle_mark() == NULL, "check we have reached the end");
350
351 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
352 // We NULL out the fields for good hygiene.
353 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL;
354 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL;
355 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL;
356 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL;
357
358 delete handle_area();
359 delete metadata_handles();
360
361 // osthread() can be NULL, if creation of thread failed.
362 if (osthread() != NULL) os::free_thread(osthread());
363
364 delete _SR_lock;
365
366 // clear thread local storage if the Thread is deleting itself
367 if (this == Thread::current()) {
368 ThreadLocalStorage::set_thread(NULL);
369 } else {
370 // In the case where we're not the current thread, invalidate all the
371 // caches in case some code tries to get the current thread or the
372 // thread that was destroyed, and gets stale information.
373 ThreadLocalStorage::invalidate_all();
374 }
375 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
376 }
377
378 // NOTE: dummy function for assertion purpose.
379 void Thread::run() {
380 ShouldNotReachHere();
381 }
382
383 #ifdef ASSERT
384 // Private method to check for dangling thread pointer
385 void check_for_dangling_thread_pointer(Thread *thread) {
386 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
387 "possibility of dangling Thread pointer");
388 }
389 #endif
390
391 ThreadPriority Thread::get_priority(const Thread* const thread) {
392 ThreadPriority priority;
393 // Can return an error!
394 (void)os::get_priority(thread, priority);
395 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
396 return priority;
397 }
398
399 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
400 debug_only(check_for_dangling_thread_pointer(thread);)
401 // Can return an error!
402 (void)os::set_priority(thread, priority);
403 }
404
405
406 void Thread::start(Thread* thread) {
407 // Start is different from resume in that its safety is guaranteed by context or
408 // being called from a Java method synchronized on the Thread object.
409 if (!DisableStartThread) {
410 if (thread->is_Java_thread()) {
411 // Initialize the thread state to RUNNABLE before starting this thread.
412 // Can not set it after the thread started because we do not know the
413 // exact thread state at that time. It could be in MONITOR_WAIT or
414 // in SLEEPING or some other state.
415 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
416 java_lang_Thread::RUNNABLE);
417 }
418 os::start_thread(thread);
419 }
420 }
421
422 // Enqueue a VM_Operation to do the job for us - sometime later
423 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
424 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
425 VMThread::execute(vm_stop);
426 }
427
428
429 // Check if an external suspend request has completed (or has been
430 // cancelled). Returns true if the thread is externally suspended and
431 // false otherwise.
432 //
433 // The bits parameter returns information about the code path through
434 // the routine. Useful for debugging:
435 //
436 // set in is_ext_suspend_completed():
437 // 0x00000001 - routine was entered
438 // 0x00000010 - routine return false at end
439 // 0x00000100 - thread exited (return false)
440 // 0x00000200 - suspend request cancelled (return false)
441 // 0x00000400 - thread suspended (return true)
442 // 0x00001000 - thread is in a suspend equivalent state (return true)
443 // 0x00002000 - thread is native and walkable (return true)
444 // 0x00004000 - thread is native_trans and walkable (needed retry)
445 //
446 // set in wait_for_ext_suspend_completion():
447 // 0x00010000 - routine was entered
448 // 0x00020000 - suspend request cancelled before loop (return false)
449 // 0x00040000 - thread suspended before loop (return true)
450 // 0x00080000 - suspend request cancelled in loop (return false)
451 // 0x00100000 - thread suspended in loop (return true)
452 // 0x00200000 - suspend not completed during retry loop (return false)
453
454 // Helper class for tracing suspend wait debug bits.
455 //
456 // 0x00000100 indicates that the target thread exited before it could
457 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
458 // 0x00080000 each indicate a cancelled suspend request so they don't
459 // count as wait failures either.
460 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
461
462 class TraceSuspendDebugBits : public StackObj {
463 private:
464 JavaThread * jt;
465 bool is_wait;
466 bool called_by_wait; // meaningful when !is_wait
467 uint32_t * bits;
468
469 public:
470 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
471 uint32_t *_bits) {
472 jt = _jt;
473 is_wait = _is_wait;
474 called_by_wait = _called_by_wait;
475 bits = _bits;
476 }
477
478 ~TraceSuspendDebugBits() {
479 if (!is_wait) {
480 #if 1
481 // By default, don't trace bits for is_ext_suspend_completed() calls.
482 // That trace is very chatty.
483 return;
484 #else
485 if (!called_by_wait) {
486 // If tracing for is_ext_suspend_completed() is enabled, then only
487 // trace calls to it from wait_for_ext_suspend_completion()
488 return;
489 }
490 #endif
491 }
492
493 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
494 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
495 MutexLocker ml(Threads_lock); // needed for get_thread_name()
496 ResourceMark rm;
497
498 tty->print_cr(
499 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
500 jt->get_thread_name(), *bits);
501
502 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
503 }
504 }
505 }
506 };
507 #undef DEBUG_FALSE_BITS
508
509
510 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
511 uint32_t *bits) {
512 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
513
514 bool did_trans_retry = false; // only do thread_in_native_trans retry once
515 bool do_trans_retry; // flag to force the retry
516
517 *bits |= 0x00000001;
518
519 do {
520 do_trans_retry = false;
521
522 if (is_exiting()) {
523 // Thread is in the process of exiting. This is always checked
524 // first to reduce the risk of dereferencing a freed JavaThread.
525 *bits |= 0x00000100;
526 return false;
527 }
528
529 if (!is_external_suspend()) {
530 // Suspend request is cancelled. This is always checked before
531 // is_ext_suspended() to reduce the risk of a rogue resume
532 // confusing the thread that made the suspend request.
533 *bits |= 0x00000200;
534 return false;
535 }
536
537 if (is_ext_suspended()) {
538 // thread is suspended
539 *bits |= 0x00000400;
540 return true;
541 }
542
543 // Now that we no longer do hard suspends of threads running
544 // native code, the target thread can be changing thread state
545 // while we are in this routine:
546 //
547 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
548 //
549 // We save a copy of the thread state as observed at this moment
550 // and make our decision about suspend completeness based on the
551 // copy. This closes the race where the thread state is seen as
552 // _thread_in_native_trans in the if-thread_blocked check, but is
553 // seen as _thread_blocked in if-thread_in_native_trans check.
554 JavaThreadState save_state = thread_state();
555
556 if (save_state == _thread_blocked && is_suspend_equivalent()) {
557 // If the thread's state is _thread_blocked and this blocking
558 // condition is known to be equivalent to a suspend, then we can
559 // consider the thread to be externally suspended. This means that
560 // the code that sets _thread_blocked has been modified to do
561 // self-suspension if the blocking condition releases. We also
562 // used to check for CONDVAR_WAIT here, but that is now covered by
563 // the _thread_blocked with self-suspension check.
564 //
565 // Return true since we wouldn't be here unless there was still an
566 // external suspend request.
567 *bits |= 0x00001000;
568 return true;
569 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
570 // Threads running native code will self-suspend on native==>VM/Java
571 // transitions. If its stack is walkable (should always be the case
572 // unless this function is called before the actual java_suspend()
573 // call), then the wait is done.
574 *bits |= 0x00002000;
575 return true;
576 } else if (!called_by_wait && !did_trans_retry &&
577 save_state == _thread_in_native_trans &&
578 frame_anchor()->walkable()) {
579 // The thread is transitioning from thread_in_native to another
580 // thread state. check_safepoint_and_suspend_for_native_trans()
581 // will force the thread to self-suspend. If it hasn't gotten
582 // there yet we may have caught the thread in-between the native
583 // code check above and the self-suspend. Lucky us. If we were
584 // called by wait_for_ext_suspend_completion(), then it
585 // will be doing the retries so we don't have to.
586 //
587 // Since we use the saved thread state in the if-statement above,
588 // there is a chance that the thread has already transitioned to
589 // _thread_blocked by the time we get here. In that case, we will
590 // make a single unnecessary pass through the logic below. This
591 // doesn't hurt anything since we still do the trans retry.
592
593 *bits |= 0x00004000;
594
595 // Once the thread leaves thread_in_native_trans for another
596 // thread state, we break out of this retry loop. We shouldn't
597 // need this flag to prevent us from getting back here, but
598 // sometimes paranoia is good.
599 did_trans_retry = true;
600
601 // We wait for the thread to transition to a more usable state.
602 for (int i = 1; i <= SuspendRetryCount; i++) {
603 // We used to do an "os::yield_all(i)" call here with the intention
604 // that yielding would increase on each retry. However, the parameter
605 // is ignored on Linux which means the yield didn't scale up. Waiting
606 // on the SR_lock below provides a much more predictable scale up for
607 // the delay. It also provides a simple/direct point to check for any
608 // safepoint requests from the VMThread
609
610 // temporarily drops SR_lock while doing wait with safepoint check
611 // (if we're a JavaThread - the WatcherThread can also call this)
612 // and increase delay with each retry
613 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
614
615 // check the actual thread state instead of what we saved above
616 if (thread_state() != _thread_in_native_trans) {
617 // the thread has transitioned to another thread state so
618 // try all the checks (except this one) one more time.
619 do_trans_retry = true;
620 break;
621 }
622 } // end retry loop
623
624
625 }
626 } while (do_trans_retry);
627
628 *bits |= 0x00000010;
629 return false;
630 }
631
632 // Wait for an external suspend request to complete (or be cancelled).
633 // Returns true if the thread is externally suspended and false otherwise.
634 //
635 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
636 uint32_t *bits) {
637 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
638 false /* !called_by_wait */, bits);
639
640 // local flag copies to minimize SR_lock hold time
641 bool is_suspended;
642 bool pending;
643 uint32_t reset_bits;
644
645 // set a marker so is_ext_suspend_completed() knows we are the caller
646 *bits |= 0x00010000;
647
648 // We use reset_bits to reinitialize the bits value at the top of
649 // each retry loop. This allows the caller to make use of any
650 // unused bits for their own marking purposes.
651 reset_bits = *bits;
652
653 {
654 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
655 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
656 delay, bits);
657 pending = is_external_suspend();
658 }
659 // must release SR_lock to allow suspension to complete
660
661 if (!pending) {
662 // A cancelled suspend request is the only false return from
663 // is_ext_suspend_completed() that keeps us from entering the
664 // retry loop.
665 *bits |= 0x00020000;
666 return false;
667 }
668
669 if (is_suspended) {
670 *bits |= 0x00040000;
671 return true;
672 }
673
674 for (int i = 1; i <= retries; i++) {
675 *bits = reset_bits; // reinit to only track last retry
676
677 // We used to do an "os::yield_all(i)" call here with the intention
678 // that yielding would increase on each retry. However, the parameter
679 // is ignored on Linux which means the yield didn't scale up. Waiting
680 // on the SR_lock below provides a much more predictable scale up for
681 // the delay. It also provides a simple/direct point to check for any
682 // safepoint requests from the VMThread
683
684 {
685 MutexLocker ml(SR_lock());
686 // wait with safepoint check (if we're a JavaThread - the WatcherThread
687 // can also call this) and increase delay with each retry
688 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
689
690 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
691 delay, bits);
692
693 // It is possible for the external suspend request to be cancelled
694 // (by a resume) before the actual suspend operation is completed.
695 // Refresh our local copy to see if we still need to wait.
696 pending = is_external_suspend();
697 }
698
699 if (!pending) {
700 // A cancelled suspend request is the only false return from
701 // is_ext_suspend_completed() that keeps us from staying in the
702 // retry loop.
703 *bits |= 0x00080000;
704 return false;
705 }
706
707 if (is_suspended) {
708 *bits |= 0x00100000;
709 return true;
710 }
711 } // end retry loop
712
713 // thread did not suspend after all our retries
714 *bits |= 0x00200000;
715 return false;
716 }
717
718 #ifndef PRODUCT
719 void JavaThread::record_jump(address target, address instr, const char* file,
720 int line) {
721
722 // This should not need to be atomic as the only way for simultaneous
723 // updates is via interrupts. Even then this should be rare or non-existent
724 // and we don't care that much anyway.
725
726 int index = _jmp_ring_index;
727 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
728 _jmp_ring[index]._target = (intptr_t) target;
729 _jmp_ring[index]._instruction = (intptr_t) instr;
730 _jmp_ring[index]._file = file;
731 _jmp_ring[index]._line = line;
732 }
733 #endif // PRODUCT
734
735 // Called by flat profiler
736 // Callers have already called wait_for_ext_suspend_completion
737 // The assertion for that is currently too complex to put here:
738 bool JavaThread::profile_last_Java_frame(frame* _fr) {
739 bool gotframe = false;
740 // self suspension saves needed state.
741 if (has_last_Java_frame() && _anchor.walkable()) {
742 *_fr = pd_last_frame();
743 gotframe = true;
744 }
745 return gotframe;
746 }
747
748 void Thread::interrupt(Thread* thread) {
749 debug_only(check_for_dangling_thread_pointer(thread);)
750 os::interrupt(thread);
751 }
752
753 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
754 debug_only(check_for_dangling_thread_pointer(thread);)
755 // Note: If clear_interrupted==false, this simply fetches and
756 // returns the value of the field osthread()->interrupted().
757 return os::is_interrupted(thread, clear_interrupted);
758 }
759
760
761 // GC Support
762 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
763 jint thread_parity = _oops_do_parity;
764 if (thread_parity != strong_roots_parity) {
765 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
766 if (res == thread_parity) {
767 return true;
768 } else {
769 guarantee(res == strong_roots_parity, "Or else what?");
770 return false;
771 }
772 }
773 return false;
774 }
775
776 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
777 active_handles()->oops_do(f);
778 // Do oop for ThreadShadow
779 f->do_oop((oop*)&_pending_exception);
780 handle_area()->oops_do(f);
781 }
782
783 void Thread::nmethods_do(CodeBlobClosure* cf) {
784 // no nmethods in a generic thread...
785 }
786
787 void Thread::metadata_handles_do(void f(Metadata*)) {
788 // Only walk the Handles in Thread.
789 if (metadata_handles() != NULL) {
790 for (int i = 0; i< metadata_handles()->length(); i++) {
791 f(metadata_handles()->at(i));
792 }
793 }
794 }
795
796 void Thread::print_on(outputStream* st) const {
797 // get_priority assumes osthread initialized
798 if (osthread() != NULL) {
799 int os_prio;
800 if (os::get_native_priority(this, &os_prio) == OS_OK) {
801 st->print("os_prio=%d ", os_prio);
802 }
803 st->print("tid=" INTPTR_FORMAT " ", this);
804 ext().print_on(st);
805 osthread()->print_on(st);
806 }
807 debug_only(if (WizardMode) print_owned_locks_on(st);)
808 }
809
810 // Thread::print_on_error() is called by fatal error handler. Don't use
811 // any lock or allocate memory.
812 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
813 if (is_VM_thread()) st->print("VMThread");
814 else if (is_Compiler_thread()) st->print("CompilerThread");
815 else if (is_Java_thread()) st->print("JavaThread");
816 else if (is_GC_task_thread()) st->print("GCTaskThread");
817 else if (is_Watcher_thread()) st->print("WatcherThread");
818 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
819 else st->print("Thread");
820
821 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
822 _stack_base - _stack_size, _stack_base);
823
824 if (osthread()) {
825 st->print(" [id=%d]", osthread()->thread_id());
826 }
827 }
828
829 #ifdef ASSERT
830 void Thread::print_owned_locks_on(outputStream* st) const {
831 Monitor *cur = _owned_locks;
832 if (cur == NULL) {
833 st->print(" (no locks) ");
834 } else {
835 st->print_cr(" Locks owned:");
836 while (cur) {
837 cur->print_on(st);
838 cur = cur->next();
839 }
840 }
841 }
842
843 static int ref_use_count = 0;
844
845 bool Thread::owns_locks_but_compiled_lock() const {
846 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
847 if (cur != Compile_lock) return true;
848 }
849 return false;
850 }
851
852
853 #endif
854
855 #ifndef PRODUCT
856
857 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
858 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
859 // no threads which allow_vm_block's are held
860 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
861 // Check if current thread is allowed to block at a safepoint
862 if (!(_allow_safepoint_count == 0)) {
863 fatal("Possible safepoint reached by thread that does not allow it");
864 }
865 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
866 fatal("LEAF method calling lock?");
867 }
868
869 #ifdef ASSERT
870 if (potential_vm_operation && is_Java_thread()
871 && !Universe::is_bootstrapping()) {
872 // Make sure we do not hold any locks that the VM thread also uses.
873 // This could potentially lead to deadlocks
874 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
875 // Threads_lock is special, since the safepoint synchronization will not start before this is
876 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
877 // since it is used to transfer control between JavaThreads and the VMThread
878 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
879 if ((cur->allow_vm_block() &&
880 cur != Threads_lock &&
881 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation
882 cur != VMOperationRequest_lock &&
883 cur != VMOperationQueue_lock) ||
884 cur->rank() == Mutex::special) {
885 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
886 }
887 }
888 }
889
890 if (GCALotAtAllSafepoints) {
891 // We could enter a safepoint here and thus have a gc
892 InterfaceSupport::check_gc_alot();
893 }
894 #endif
895 }
896 #endif
897
898 bool Thread::is_in_stack(address adr) const {
899 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
900 address end = os::current_stack_pointer();
901 // Allow non Java threads to call this without stack_base
902 if (_stack_base == NULL) return true;
903 if (stack_base() >= adr && adr >= end) return true;
904
905 return false;
906 }
907
908
909 bool Thread::is_in_usable_stack(address adr) const {
910 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
911 size_t usable_stack_size = _stack_size - stack_guard_size;
912
913 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
914 }
915
916
917 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
918 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
919 // used for compilation in the future. If that change is made, the need for these methods
920 // should be revisited, and they should be removed if possible.
921
922 bool Thread::is_lock_owned(address adr) const {
923 return on_local_stack(adr);
924 }
925
926 bool Thread::set_as_starting_thread() {
927 // NOTE: this must be called inside the main thread.
928 return os::create_main_thread((JavaThread*)this);
929 }
930
931 static void initialize_class(Symbol* class_name, TRAPS) {
932 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
933 InstanceKlass::cast(klass)->initialize(CHECK);
934 }
935
936
937 // Creates the initial ThreadGroup
938 static Handle create_initial_thread_group(TRAPS) {
939 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
940 instanceKlassHandle klass (THREAD, k);
941
942 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
943 {
944 JavaValue result(T_VOID);
945 JavaCalls::call_special(&result,
946 system_instance,
947 klass,
948 vmSymbols::object_initializer_name(),
949 vmSymbols::void_method_signature(),
950 CHECK_NH);
951 }
952 Universe::set_system_thread_group(system_instance());
953
954 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
955 {
956 JavaValue result(T_VOID);
957 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
958 JavaCalls::call_special(&result,
959 main_instance,
960 klass,
961 vmSymbols::object_initializer_name(),
962 vmSymbols::threadgroup_string_void_signature(),
963 system_instance,
964 string,
965 CHECK_NH);
966 }
967 return main_instance;
968 }
969
970 // Creates the initial Thread
971 static oop create_initial_thread(Handle thread_group, JavaThread* thread,
972 TRAPS) {
973 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
974 instanceKlassHandle klass (THREAD, k);
975 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
976
977 java_lang_Thread::set_thread(thread_oop(), thread);
978 java_lang_Thread::set_priority(thread_oop(), NormPriority);
979 thread->set_threadObj(thread_oop());
980
981 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
982
983 JavaValue result(T_VOID);
984 JavaCalls::call_special(&result, thread_oop,
985 klass,
986 vmSymbols::object_initializer_name(),
987 vmSymbols::threadgroup_string_void_signature(),
988 thread_group,
989 string,
990 CHECK_NULL);
991 return thread_oop();
992 }
993
994 static void call_initializeSystemClass(TRAPS) {
995 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
996 instanceKlassHandle klass (THREAD, k);
997
998 JavaValue result(T_VOID);
999 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1000 vmSymbols::void_method_signature(), CHECK);
1001 }
1002
1003 char java_runtime_name[128] = "";
1004 char java_runtime_version[128] = "";
1005
1006 // extract the JRE name from sun.misc.Version.java_runtime_name
1007 static const char* get_java_runtime_name(TRAPS) {
1008 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1009 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1010 fieldDescriptor fd;
1011 bool found = k != NULL &&
1012 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1013 vmSymbols::string_signature(), &fd);
1014 if (found) {
1015 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1016 if (name_oop == NULL) {
1017 return NULL;
1018 }
1019 const char* name = java_lang_String::as_utf8_string(name_oop,
1020 java_runtime_name,
1021 sizeof(java_runtime_name));
1022 return name;
1023 } else {
1024 return NULL;
1025 }
1026 }
1027
1028 // extract the JRE version from sun.misc.Version.java_runtime_version
1029 static const char* get_java_runtime_version(TRAPS) {
1030 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1031 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1032 fieldDescriptor fd;
1033 bool found = k != NULL &&
1034 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1035 vmSymbols::string_signature(), &fd);
1036 if (found) {
1037 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1038 if (name_oop == NULL) {
1039 return NULL;
1040 }
1041 const char* name = java_lang_String::as_utf8_string(name_oop,
1042 java_runtime_version,
1043 sizeof(java_runtime_version));
1044 return name;
1045 } else {
1046 return NULL;
1047 }
1048 }
1049
1050 // General purpose hook into Java code, run once when the VM is initialized.
1051 // The Java library method itself may be changed independently from the VM.
1052 static void call_postVMInitHook(TRAPS) {
1053 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1054 instanceKlassHandle klass (THREAD, k);
1055 if (klass.not_null()) {
1056 JavaValue result(T_VOID);
1057 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1058 vmSymbols::void_method_signature(),
1059 CHECK);
1060 }
1061 }
1062
1063 static void reset_vm_info_property(TRAPS) {
1064 // the vm info string
1065 ResourceMark rm(THREAD);
1066 const char *vm_info = VM_Version::vm_info_string();
1067
1068 // java.lang.System class
1069 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1070 instanceKlassHandle klass (THREAD, k);
1071
1072 // setProperty arguments
1073 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1074 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1075
1076 // return value
1077 JavaValue r(T_OBJECT);
1078
1079 // public static String setProperty(String key, String value);
1080 JavaCalls::call_static(&r,
1081 klass,
1082 vmSymbols::setProperty_name(),
1083 vmSymbols::string_string_string_signature(),
1084 key_str,
1085 value_str,
1086 CHECK);
1087 }
1088
1089
1090 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
1091 bool daemon, TRAPS) {
1092 assert(thread_group.not_null(), "thread group should be specified");
1093 assert(threadObj() == NULL, "should only create Java thread object once");
1094
1095 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1096 instanceKlassHandle klass (THREAD, k);
1097 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1098
1099 java_lang_Thread::set_thread(thread_oop(), this);
1100 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1101 set_threadObj(thread_oop());
1102
1103 JavaValue result(T_VOID);
1104 if (thread_name != NULL) {
1105 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1106 // Thread gets assigned specified name and null target
1107 JavaCalls::call_special(&result,
1108 thread_oop,
1109 klass,
1110 vmSymbols::object_initializer_name(),
1111 vmSymbols::threadgroup_string_void_signature(),
1112 thread_group, // Argument 1
1113 name, // Argument 2
1114 THREAD);
1115 } else {
1116 // Thread gets assigned name "Thread-nnn" and null target
1117 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1118 JavaCalls::call_special(&result,
1119 thread_oop,
1120 klass,
1121 vmSymbols::object_initializer_name(),
1122 vmSymbols::threadgroup_runnable_void_signature(),
1123 thread_group, // Argument 1
1124 Handle(), // Argument 2
1125 THREAD);
1126 }
1127
1128
1129 if (daemon) {
1130 java_lang_Thread::set_daemon(thread_oop());
1131 }
1132
1133 if (HAS_PENDING_EXCEPTION) {
1134 return;
1135 }
1136
1137 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass());
1138 Handle threadObj(THREAD, this->threadObj());
1139
1140 JavaCalls::call_special(&result,
1141 thread_group,
1142 group,
1143 vmSymbols::add_method_name(),
1144 vmSymbols::thread_void_signature(),
1145 threadObj, // Arg 1
1146 THREAD);
1147 }
1148
1149 // NamedThread -- non-JavaThread subclasses with multiple
1150 // uniquely named instances should derive from this.
1151 NamedThread::NamedThread() : Thread() {
1152 _name = NULL;
1153 _processed_thread = NULL;
1154 }
1155
1156 NamedThread::~NamedThread() {
1157 if (_name != NULL) {
1158 FREE_C_HEAP_ARRAY(char, _name);
1159 _name = NULL;
1160 }
1161 }
1162
1163 void NamedThread::set_name(const char* format, ...) {
1164 guarantee(_name == NULL, "Only get to set name once.");
1165 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1166 guarantee(_name != NULL, "alloc failure");
1167 va_list ap;
1168 va_start(ap, format);
1169 jio_vsnprintf(_name, max_name_len, format, ap);
1170 va_end(ap);
1171 }
1172
1173 void NamedThread::initialize_named_thread() {
1174 set_native_thread_name(name());
1175 }
1176
1177 void NamedThread::print_on(outputStream* st) const {
1178 st->print("\"%s\" ", name());
1179 Thread::print_on(st);
1180 st->cr();
1181 }
1182
1183
1184 // ======= WatcherThread ========
1185
1186 // The watcher thread exists to simulate timer interrupts. It should
1187 // be replaced by an abstraction over whatever native support for
1188 // timer interrupts exists on the platform.
1189
1190 WatcherThread* WatcherThread::_watcher_thread = NULL;
1191 bool WatcherThread::_startable = false;
1192 volatile bool WatcherThread::_should_terminate = false;
1193
1194 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1195 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1196 if (os::create_thread(this, os::watcher_thread)) {
1197 _watcher_thread = this;
1198
1199 // Set the watcher thread to the highest OS priority which should not be
1200 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1201 // is created. The only normal thread using this priority is the reference
1202 // handler thread, which runs for very short intervals only.
1203 // If the VMThread's priority is not lower than the WatcherThread profiling
1204 // will be inaccurate.
1205 os::set_priority(this, MaxPriority);
1206 if (!DisableStartThread) {
1207 os::start_thread(this);
1208 }
1209 }
1210 }
1211
1212 int WatcherThread::sleep() const {
1213 // The WatcherThread does not participate in the safepoint protocol
1214 // for the PeriodicTask_lock because it is not a JavaThread.
1215 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1216
1217 if (_should_terminate) {
1218 // check for termination before we do any housekeeping or wait
1219 return 0; // we did not sleep.
1220 }
1221
1222 // remaining will be zero if there are no tasks,
1223 // causing the WatcherThread to sleep until a task is
1224 // enrolled
1225 int remaining = PeriodicTask::time_to_wait();
1226 int time_slept = 0;
1227
1228 // we expect this to timeout - we only ever get unparked when
1229 // we should terminate or when a new task has been enrolled
1230 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1231
1232 jlong time_before_loop = os::javaTimeNanos();
1233
1234 while (true) {
1235 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
1236 remaining);
1237 jlong now = os::javaTimeNanos();
1238
1239 if (remaining == 0) {
1240 // if we didn't have any tasks we could have waited for a long time
1241 // consider the time_slept zero and reset time_before_loop
1242 time_slept = 0;
1243 time_before_loop = now;
1244 } else {
1245 // need to recalculate since we might have new tasks in _tasks
1246 time_slept = (int) ((now - time_before_loop) / 1000000);
1247 }
1248
1249 // Change to task list or spurious wakeup of some kind
1250 if (timedout || _should_terminate) {
1251 break;
1252 }
1253
1254 remaining = PeriodicTask::time_to_wait();
1255 if (remaining == 0) {
1256 // Last task was just disenrolled so loop around and wait until
1257 // another task gets enrolled
1258 continue;
1259 }
1260
1261 remaining -= time_slept;
1262 if (remaining <= 0) {
1263 break;
1264 }
1265 }
1266
1267 return time_slept;
1268 }
1269
1270 void WatcherThread::run() {
1271 assert(this == watcher_thread(), "just checking");
1272
1273 this->record_stack_base_and_size();
1274 this->initialize_thread_local_storage();
1275 this->set_native_thread_name(this->name());
1276 this->set_active_handles(JNIHandleBlock::allocate_block());
1277 while (true) {
1278 assert(watcher_thread() == Thread::current(), "thread consistency check");
1279 assert(watcher_thread() == this, "thread consistency check");
1280
1281 // Calculate how long it'll be until the next PeriodicTask work
1282 // should be done, and sleep that amount of time.
1283 int time_waited = sleep();
1284
1285 if (is_error_reported()) {
1286 // A fatal error has happened, the error handler(VMError::report_and_die)
1287 // should abort JVM after creating an error log file. However in some
1288 // rare cases, the error handler itself might deadlock. Here we try to
1289 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1290 //
1291 // This code is in WatcherThread because WatcherThread wakes up
1292 // periodically so the fatal error handler doesn't need to do anything;
1293 // also because the WatcherThread is less likely to crash than other
1294 // threads.
1295
1296 for (;;) {
1297 if (!ShowMessageBoxOnError
1298 && (OnError == NULL || OnError[0] == '\0')
1299 && Arguments::abort_hook() == NULL) {
1300 os::sleep(this, ErrorLogTimeout * 60 * 1000, false);
1301 fdStream err(defaultStream::output_fd());
1302 err.print_raw_cr("# [ timer expired, abort... ]");
1303 // skip atexit/vm_exit/vm_abort hooks
1304 os::die();
1305 }
1306
1307 // Wake up 5 seconds later, the fatal handler may reset OnError or
1308 // ShowMessageBoxOnError when it is ready to abort.
1309 os::sleep(this, 5 * 1000, false);
1310 }
1311 }
1312
1313 if (_should_terminate) {
1314 // check for termination before posting the next tick
1315 break;
1316 }
1317
1318 PeriodicTask::real_time_tick(time_waited);
1319 }
1320
1321 // Signal that it is terminated
1322 {
1323 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1324 _watcher_thread = NULL;
1325 Terminator_lock->notify();
1326 }
1327
1328 // Thread destructor usually does this..
1329 ThreadLocalStorage::set_thread(NULL);
1330 }
1331
1332 void WatcherThread::start() {
1333 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1334
1335 if (watcher_thread() == NULL && _startable) {
1336 _should_terminate = false;
1337 // Create the single instance of WatcherThread
1338 new WatcherThread();
1339 }
1340 }
1341
1342 void WatcherThread::make_startable() {
1343 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1344 _startable = true;
1345 }
1346
1347 void WatcherThread::stop() {
1348 {
1349 // Follow normal safepoint aware lock enter protocol since the
1350 // WatcherThread is stopped by another JavaThread.
1351 MutexLocker ml(PeriodicTask_lock);
1352 _should_terminate = true;
1353
1354 WatcherThread* watcher = watcher_thread();
1355 if (watcher != NULL) {
1356 // unpark the WatcherThread so it can see that it should terminate
1357 watcher->unpark();
1358 }
1359 }
1360
1361 MutexLocker mu(Terminator_lock);
1362
1363 while (watcher_thread() != NULL) {
1364 // This wait should make safepoint checks, wait without a timeout,
1365 // and wait as a suspend-equivalent condition.
1366 //
1367 // Note: If the FlatProfiler is running, then this thread is waiting
1368 // for the WatcherThread to terminate and the WatcherThread, via the
1369 // FlatProfiler task, is waiting for the external suspend request on
1370 // this thread to complete. wait_for_ext_suspend_completion() will
1371 // eventually timeout, but that takes time. Making this wait a
1372 // suspend-equivalent condition solves that timeout problem.
1373 //
1374 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1375 Mutex::_as_suspend_equivalent_flag);
1376 }
1377 }
1378
1379 void WatcherThread::unpark() {
1380 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1381 PeriodicTask_lock->notify();
1382 }
1383
1384 void WatcherThread::print_on(outputStream* st) const {
1385 st->print("\"%s\" ", name());
1386 Thread::print_on(st);
1387 st->cr();
1388 }
1389
1390 // ======= JavaThread ========
1391
1392 // A JavaThread is a normal Java thread
1393
1394 void JavaThread::initialize() {
1395 // Initialize fields
1396
1397 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1398 set_claimed_par_id(UINT_MAX);
1399
1400 set_saved_exception_pc(NULL);
1401 set_threadObj(NULL);
1402 _anchor.clear();
1403 set_entry_point(NULL);
1404 set_jni_functions(jni_functions());
1405 set_callee_target(NULL);
1406 set_vm_result(NULL);
1407 set_vm_result_2(NULL);
1408 set_vframe_array_head(NULL);
1409 set_vframe_array_last(NULL);
1410 set_deferred_locals(NULL);
1411 set_deopt_mark(NULL);
1412 set_deopt_nmethod(NULL);
1413 clear_must_deopt_id();
1414 set_monitor_chunks(NULL);
1415 set_next(NULL);
1416 set_thread_state(_thread_new);
1417 _terminated = _not_terminated;
1418 _privileged_stack_top = NULL;
1419 _array_for_gc = NULL;
1420 _suspend_equivalent = false;
1421 _in_deopt_handler = 0;
1422 _doing_unsafe_access = false;
1423 _stack_guard_state = stack_guard_unused;
1424 (void)const_cast<oop&>(_exception_oop = oop(NULL));
1425 _exception_pc = 0;
1426 _exception_handler_pc = 0;
1427 _is_method_handle_return = 0;
1428 _jvmti_thread_state= NULL;
1429 _should_post_on_exceptions_flag = JNI_FALSE;
1430 _jvmti_get_loaded_classes_closure = NULL;
1431 _interp_only_mode = 0;
1432 _special_runtime_exit_condition = _no_async_condition;
1433 _pending_async_exception = NULL;
1434 _thread_stat = NULL;
1435 _thread_stat = new ThreadStatistics();
1436 _blocked_on_compilation = false;
1437 _jni_active_critical = 0;
1438 _pending_jni_exception_check_fn = NULL;
1439 _do_not_unlock_if_synchronized = false;
1440 _cached_monitor_info = NULL;
1441 _parker = Parker::Allocate(this);
1442
1443 #ifndef PRODUCT
1444 _jmp_ring_index = 0;
1445 for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
1446 record_jump(NULL, NULL, NULL, 0);
1447 }
1448 #endif // PRODUCT
1449
1450 set_thread_profiler(NULL);
1451 if (FlatProfiler::is_active()) {
1452 // This is where we would decide to either give each thread it's own profiler
1453 // or use one global one from FlatProfiler,
1454 // or up to some count of the number of profiled threads, etc.
1455 ThreadProfiler* pp = new ThreadProfiler();
1456 pp->engage();
1457 set_thread_profiler(pp);
1458 }
1459
1460 // Setup safepoint state info for this thread
1461 ThreadSafepointState::create(this);
1462
1463 debug_only(_java_call_counter = 0);
1464
1465 // JVMTI PopFrame support
1466 _popframe_condition = popframe_inactive;
1467 _popframe_preserved_args = NULL;
1468 _popframe_preserved_args_size = 0;
1469 _frames_to_pop_failed_realloc = 0;
1470
1471 pd_initialize();
1472 }
1473
1474 #if INCLUDE_ALL_GCS
1475 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1476 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1477 #endif // INCLUDE_ALL_GCS
1478
1479 JavaThread::JavaThread(bool is_attaching_via_jni) :
1480 Thread()
1481 #if INCLUDE_ALL_GCS
1482 , _satb_mark_queue(&_satb_mark_queue_set),
1483 _dirty_card_queue(&_dirty_card_queue_set)
1484 #endif // INCLUDE_ALL_GCS
1485 {
1486 initialize();
1487 if (is_attaching_via_jni) {
1488 _jni_attach_state = _attaching_via_jni;
1489 } else {
1490 _jni_attach_state = _not_attaching_via_jni;
1491 }
1492 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1493 }
1494
1495 bool JavaThread::reguard_stack(address cur_sp) {
1496 if (_stack_guard_state != stack_guard_yellow_disabled) {
1497 return true; // Stack already guarded or guard pages not needed.
1498 }
1499
1500 if (register_stack_overflow()) {
1501 // For those architectures which have separate register and
1502 // memory stacks, we must check the register stack to see if
1503 // it has overflowed.
1504 return false;
1505 }
1506
1507 // Java code never executes within the yellow zone: the latter is only
1508 // there to provoke an exception during stack banging. If java code
1509 // is executing there, either StackShadowPages should be larger, or
1510 // some exception code in c1, c2 or the interpreter isn't unwinding
1511 // when it should.
1512 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1513
1514 enable_stack_yellow_zone();
1515 return true;
1516 }
1517
1518 bool JavaThread::reguard_stack(void) {
1519 return reguard_stack(os::current_stack_pointer());
1520 }
1521
1522
1523 void JavaThread::block_if_vm_exited() {
1524 if (_terminated == _vm_exited) {
1525 // _vm_exited is set at safepoint, and Threads_lock is never released
1526 // we will block here forever
1527 Threads_lock->lock_without_safepoint_check();
1528 ShouldNotReachHere();
1529 }
1530 }
1531
1532
1533 // Remove this ifdef when C1 is ported to the compiler interface.
1534 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1535 static void sweeper_thread_entry(JavaThread* thread, TRAPS);
1536
1537 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1538 Thread()
1539 #if INCLUDE_ALL_GCS
1540 , _satb_mark_queue(&_satb_mark_queue_set),
1541 _dirty_card_queue(&_dirty_card_queue_set)
1542 #endif // INCLUDE_ALL_GCS
1543 {
1544 initialize();
1545 _jni_attach_state = _not_attaching_via_jni;
1546 set_entry_point(entry_point);
1547 // Create the native thread itself.
1548 // %note runtime_23
1549 os::ThreadType thr_type = os::java_thread;
1550 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1551 os::java_thread;
1552 os::create_thread(this, thr_type, stack_sz);
1553 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1554 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1555 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1556 // the exception consists of creating the exception object & initializing it, initialization
1557 // will leave the VM via a JavaCall and then all locks must be unlocked).
1558 //
1559 // The thread is still suspended when we reach here. Thread must be explicit started
1560 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1561 // by calling Threads:add. The reason why this is not done here, is because the thread
1562 // object must be fully initialized (take a look at JVM_Start)
1563 }
1564
1565 JavaThread::~JavaThread() {
1566
1567 // JSR166 -- return the parker to the free list
1568 Parker::Release(_parker);
1569 _parker = NULL;
1570
1571 // Free any remaining previous UnrollBlock
1572 vframeArray* old_array = vframe_array_last();
1573
1574 if (old_array != NULL) {
1575 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1576 old_array->set_unroll_block(NULL);
1577 delete old_info;
1578 delete old_array;
1579 }
1580
1581 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1582 if (deferred != NULL) {
1583 // This can only happen if thread is destroyed before deoptimization occurs.
1584 assert(deferred->length() != 0, "empty array!");
1585 do {
1586 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1587 deferred->remove_at(0);
1588 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1589 delete dlv;
1590 } while (deferred->length() != 0);
1591 delete deferred;
1592 }
1593
1594 // All Java related clean up happens in exit
1595 ThreadSafepointState::destroy(this);
1596 if (_thread_profiler != NULL) delete _thread_profiler;
1597 if (_thread_stat != NULL) delete _thread_stat;
1598 }
1599
1600
1601 // The first routine called by a new Java thread
1602 void JavaThread::run() {
1603 // initialize thread-local alloc buffer related fields
1604 this->initialize_tlab();
1605
1606 // used to test validity of stack trace backs
1607 this->record_base_of_stack_pointer();
1608
1609 // Record real stack base and size.
1610 this->record_stack_base_and_size();
1611
1612 // Initialize thread local storage; set before calling MutexLocker
1613 this->initialize_thread_local_storage();
1614
1615 this->create_stack_guard_pages();
1616
1617 this->cache_global_variables();
1618
1619 // Thread is now sufficient initialized to be handled by the safepoint code as being
1620 // in the VM. Change thread state from _thread_new to _thread_in_vm
1621 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1622
1623 assert(JavaThread::current() == this, "sanity check");
1624 assert(!Thread::current()->owns_locks(), "sanity check");
1625
1626 DTRACE_THREAD_PROBE(start, this);
1627
1628 // This operation might block. We call that after all safepoint checks for a new thread has
1629 // been completed.
1630 this->set_active_handles(JNIHandleBlock::allocate_block());
1631
1632 if (JvmtiExport::should_post_thread_life()) {
1633 JvmtiExport::post_thread_start(this);
1634 }
1635
1636 EventThreadStart event;
1637 if (event.should_commit()) {
1638 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1639 event.commit();
1640 }
1641
1642 // We call another function to do the rest so we are sure that the stack addresses used
1643 // from there will be lower than the stack base just computed
1644 thread_main_inner();
1645
1646 // Note, thread is no longer valid at this point!
1647 }
1648
1649
1650 void JavaThread::thread_main_inner() {
1651 assert(JavaThread::current() == this, "sanity check");
1652 assert(this->threadObj() != NULL, "just checking");
1653
1654 // Execute thread entry point unless this thread has a pending exception
1655 // or has been stopped before starting.
1656 // Note: Due to JVM_StopThread we can have pending exceptions already!
1657 if (!this->has_pending_exception() &&
1658 !java_lang_Thread::is_stillborn(this->threadObj())) {
1659 {
1660 ResourceMark rm(this);
1661 this->set_native_thread_name(this->get_thread_name());
1662 }
1663 HandleMark hm(this);
1664 this->entry_point()(this, this);
1665 }
1666
1667 DTRACE_THREAD_PROBE(stop, this);
1668
1669 this->exit(false);
1670 delete this;
1671 }
1672
1673
1674 static void ensure_join(JavaThread* thread) {
1675 // We do not need to grap the Threads_lock, since we are operating on ourself.
1676 Handle threadObj(thread, thread->threadObj());
1677 assert(threadObj.not_null(), "java thread object must exist");
1678 ObjectLocker lock(threadObj, thread);
1679 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1680 thread->clear_pending_exception();
1681 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1682 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1683 // Clear the native thread instance - this makes isAlive return false and allows the join()
1684 // to complete once we've done the notify_all below
1685 java_lang_Thread::set_thread(threadObj(), NULL);
1686 lock.notify_all(thread);
1687 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1688 thread->clear_pending_exception();
1689 }
1690
1691
1692 // For any new cleanup additions, please check to see if they need to be applied to
1693 // cleanup_failed_attach_current_thread as well.
1694 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1695 assert(this == JavaThread::current(), "thread consistency check");
1696
1697 HandleMark hm(this);
1698 Handle uncaught_exception(this, this->pending_exception());
1699 this->clear_pending_exception();
1700 Handle threadObj(this, this->threadObj());
1701 assert(threadObj.not_null(), "Java thread object should be created");
1702
1703 if (get_thread_profiler() != NULL) {
1704 get_thread_profiler()->disengage();
1705 ResourceMark rm;
1706 get_thread_profiler()->print(get_thread_name());
1707 }
1708
1709
1710 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1711 {
1712 EXCEPTION_MARK;
1713
1714 CLEAR_PENDING_EXCEPTION;
1715 }
1716 if (!destroy_vm) {
1717 if (uncaught_exception.not_null()) {
1718 EXCEPTION_MARK;
1719 // Call method Thread.dispatchUncaughtException().
1720 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1721 JavaValue result(T_VOID);
1722 JavaCalls::call_virtual(&result,
1723 threadObj, thread_klass,
1724 vmSymbols::dispatchUncaughtException_name(),
1725 vmSymbols::throwable_void_signature(),
1726 uncaught_exception,
1727 THREAD);
1728 if (HAS_PENDING_EXCEPTION) {
1729 ResourceMark rm(this);
1730 jio_fprintf(defaultStream::error_stream(),
1731 "\nException: %s thrown from the UncaughtExceptionHandler"
1732 " in thread \"%s\"\n",
1733 pending_exception()->klass()->external_name(),
1734 get_thread_name());
1735 CLEAR_PENDING_EXCEPTION;
1736 }
1737 }
1738
1739 // Called before the java thread exit since we want to read info
1740 // from java_lang_Thread object
1741 EventThreadEnd event;
1742 if (event.should_commit()) {
1743 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1744 event.commit();
1745 }
1746
1747 // Call after last event on thread
1748 EVENT_THREAD_EXIT(this);
1749
1750 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1751 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1752 // is deprecated anyhow.
1753 if (!is_Compiler_thread()) {
1754 int count = 3;
1755 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1756 EXCEPTION_MARK;
1757 JavaValue result(T_VOID);
1758 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1759 JavaCalls::call_virtual(&result,
1760 threadObj, thread_klass,
1761 vmSymbols::exit_method_name(),
1762 vmSymbols::void_method_signature(),
1763 THREAD);
1764 CLEAR_PENDING_EXCEPTION;
1765 }
1766 }
1767 // notify JVMTI
1768 if (JvmtiExport::should_post_thread_life()) {
1769 JvmtiExport::post_thread_end(this);
1770 }
1771
1772 // We have notified the agents that we are exiting, before we go on,
1773 // we must check for a pending external suspend request and honor it
1774 // in order to not surprise the thread that made the suspend request.
1775 while (true) {
1776 {
1777 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1778 if (!is_external_suspend()) {
1779 set_terminated(_thread_exiting);
1780 ThreadService::current_thread_exiting(this);
1781 break;
1782 }
1783 // Implied else:
1784 // Things get a little tricky here. We have a pending external
1785 // suspend request, but we are holding the SR_lock so we
1786 // can't just self-suspend. So we temporarily drop the lock
1787 // and then self-suspend.
1788 }
1789
1790 ThreadBlockInVM tbivm(this);
1791 java_suspend_self();
1792
1793 // We're done with this suspend request, but we have to loop around
1794 // and check again. Eventually we will get SR_lock without a pending
1795 // external suspend request and will be able to mark ourselves as
1796 // exiting.
1797 }
1798 // no more external suspends are allowed at this point
1799 } else {
1800 // before_exit() has already posted JVMTI THREAD_END events
1801 }
1802
1803 // Notify waiters on thread object. This has to be done after exit() is called
1804 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1805 // group should have the destroyed bit set before waiters are notified).
1806 ensure_join(this);
1807 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1808
1809 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1810 // held by this thread must be released. The spec does not distinguish
1811 // between JNI-acquired and regular Java monitors. We can only see
1812 // regular Java monitors here if monitor enter-exit matching is broken.
1813 //
1814 // Optionally release any monitors for regular JavaThread exits. This
1815 // is provided as a work around for any bugs in monitor enter-exit
1816 // matching. This can be expensive so it is not enabled by default.
1817 // ObjectMonitor::Knob_ExitRelease is a superset of the
1818 // JNIDetachReleasesMonitors option.
1819 //
1820 // ensure_join() ignores IllegalThreadStateExceptions, and so does
1821 // ObjectSynchronizer::release_monitors_owned_by_thread().
1822 if ((exit_type == jni_detach && JNIDetachReleasesMonitors) ||
1823 ObjectMonitor::Knob_ExitRelease) {
1824 // Sanity check even though JNI DetachCurrentThread() would have
1825 // returned JNI_ERR if there was a Java frame. JavaThread exit
1826 // should be done executing Java code by the time we get here.
1827 assert(!this->has_last_Java_frame(),
1828 "should not have a Java frame when detaching or exiting");
1829 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1830 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1831 }
1832
1833 // These things needs to be done while we are still a Java Thread. Make sure that thread
1834 // is in a consistent state, in case GC happens
1835 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1836
1837 if (active_handles() != NULL) {
1838 JNIHandleBlock* block = active_handles();
1839 set_active_handles(NULL);
1840 JNIHandleBlock::release_block(block);
1841 }
1842
1843 if (free_handle_block() != NULL) {
1844 JNIHandleBlock* block = free_handle_block();
1845 set_free_handle_block(NULL);
1846 JNIHandleBlock::release_block(block);
1847 }
1848
1849 // These have to be removed while this is still a valid thread.
1850 remove_stack_guard_pages();
1851
1852 if (UseTLAB) {
1853 tlab().make_parsable(true); // retire TLAB
1854 }
1855
1856 if (JvmtiEnv::environments_might_exist()) {
1857 JvmtiExport::cleanup_thread(this);
1858 }
1859
1860 // We must flush any deferred card marks before removing a thread from
1861 // the list of active threads.
1862 Universe::heap()->flush_deferred_store_barrier(this);
1863 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1864
1865 #if INCLUDE_ALL_GCS
1866 // We must flush the G1-related buffers before removing a thread
1867 // from the list of active threads. We must do this after any deferred
1868 // card marks have been flushed (above) so that any entries that are
1869 // added to the thread's dirty card queue as a result are not lost.
1870 if (UseG1GC) {
1871 flush_barrier_queues();
1872 }
1873 #endif // INCLUDE_ALL_GCS
1874
1875 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1876 Threads::remove(this);
1877 }
1878
1879 #if INCLUDE_ALL_GCS
1880 // Flush G1-related queues.
1881 void JavaThread::flush_barrier_queues() {
1882 satb_mark_queue().flush();
1883 dirty_card_queue().flush();
1884 }
1885
1886 void JavaThread::initialize_queues() {
1887 assert(!SafepointSynchronize::is_at_safepoint(),
1888 "we should not be at a safepoint");
1889
1890 ObjPtrQueue& satb_queue = satb_mark_queue();
1891 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1892 // The SATB queue should have been constructed with its active
1893 // field set to false.
1894 assert(!satb_queue.is_active(), "SATB queue should not be active");
1895 assert(satb_queue.is_empty(), "SATB queue should be empty");
1896 // If we are creating the thread during a marking cycle, we should
1897 // set the active field of the SATB queue to true.
1898 if (satb_queue_set.is_active()) {
1899 satb_queue.set_active(true);
1900 }
1901
1902 DirtyCardQueue& dirty_queue = dirty_card_queue();
1903 // The dirty card queue should have been constructed with its
1904 // active field set to true.
1905 assert(dirty_queue.is_active(), "dirty card queue should be active");
1906 }
1907 #endif // INCLUDE_ALL_GCS
1908
1909 void JavaThread::cleanup_failed_attach_current_thread() {
1910 if (get_thread_profiler() != NULL) {
1911 get_thread_profiler()->disengage();
1912 ResourceMark rm;
1913 get_thread_profiler()->print(get_thread_name());
1914 }
1915
1916 if (active_handles() != NULL) {
1917 JNIHandleBlock* block = active_handles();
1918 set_active_handles(NULL);
1919 JNIHandleBlock::release_block(block);
1920 }
1921
1922 if (free_handle_block() != NULL) {
1923 JNIHandleBlock* block = free_handle_block();
1924 set_free_handle_block(NULL);
1925 JNIHandleBlock::release_block(block);
1926 }
1927
1928 // These have to be removed while this is still a valid thread.
1929 remove_stack_guard_pages();
1930
1931 if (UseTLAB) {
1932 tlab().make_parsable(true); // retire TLAB, if any
1933 }
1934
1935 #if INCLUDE_ALL_GCS
1936 if (UseG1GC) {
1937 flush_barrier_queues();
1938 }
1939 #endif // INCLUDE_ALL_GCS
1940
1941 Threads::remove(this);
1942 delete this;
1943 }
1944
1945
1946
1947
1948 JavaThread* JavaThread::active() {
1949 Thread* thread = ThreadLocalStorage::thread();
1950 assert(thread != NULL, "just checking");
1951 if (thread->is_Java_thread()) {
1952 return (JavaThread*) thread;
1953 } else {
1954 assert(thread->is_VM_thread(), "this must be a vm thread");
1955 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1956 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1957 assert(ret->is_Java_thread(), "must be a Java thread");
1958 return ret;
1959 }
1960 }
1961
1962 bool JavaThread::is_lock_owned(address adr) const {
1963 if (Thread::is_lock_owned(adr)) return true;
1964
1965 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1966 if (chunk->contains(adr)) return true;
1967 }
1968
1969 return false;
1970 }
1971
1972
1973 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1974 chunk->set_next(monitor_chunks());
1975 set_monitor_chunks(chunk);
1976 }
1977
1978 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1979 guarantee(monitor_chunks() != NULL, "must be non empty");
1980 if (monitor_chunks() == chunk) {
1981 set_monitor_chunks(chunk->next());
1982 } else {
1983 MonitorChunk* prev = monitor_chunks();
1984 while (prev->next() != chunk) prev = prev->next();
1985 prev->set_next(chunk->next());
1986 }
1987 }
1988
1989 // JVM support.
1990
1991 // Note: this function shouldn't block if it's called in
1992 // _thread_in_native_trans state (such as from
1993 // check_special_condition_for_native_trans()).
1994 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1995
1996 if (has_last_Java_frame() && has_async_condition()) {
1997 // If we are at a polling page safepoint (not a poll return)
1998 // then we must defer async exception because live registers
1999 // will be clobbered by the exception path. Poll return is
2000 // ok because the call we a returning from already collides
2001 // with exception handling registers and so there is no issue.
2002 // (The exception handling path kills call result registers but
2003 // this is ok since the exception kills the result anyway).
2004
2005 if (is_at_poll_safepoint()) {
2006 // if the code we are returning to has deoptimized we must defer
2007 // the exception otherwise live registers get clobbered on the
2008 // exception path before deoptimization is able to retrieve them.
2009 //
2010 RegisterMap map(this, false);
2011 frame caller_fr = last_frame().sender(&map);
2012 assert(caller_fr.is_compiled_frame(), "what?");
2013 if (caller_fr.is_deoptimized_frame()) {
2014 if (TraceExceptions) {
2015 ResourceMark rm;
2016 tty->print_cr("deferred async exception at compiled safepoint");
2017 }
2018 return;
2019 }
2020 }
2021 }
2022
2023 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2024 if (condition == _no_async_condition) {
2025 // Conditions have changed since has_special_runtime_exit_condition()
2026 // was called:
2027 // - if we were here only because of an external suspend request,
2028 // then that was taken care of above (or cancelled) so we are done
2029 // - if we were here because of another async request, then it has
2030 // been cleared between the has_special_runtime_exit_condition()
2031 // and now so again we are done
2032 return;
2033 }
2034
2035 // Check for pending async. exception
2036 if (_pending_async_exception != NULL) {
2037 // Only overwrite an already pending exception, if it is not a threadDeath.
2038 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2039
2040 // We cannot call Exceptions::_throw(...) here because we cannot block
2041 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2042
2043 if (TraceExceptions) {
2044 ResourceMark rm;
2045 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2046 if (has_last_Java_frame()) {
2047 frame f = last_frame();
2048 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2049 }
2050 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2051 }
2052 _pending_async_exception = NULL;
2053 clear_has_async_exception();
2054 }
2055 }
2056
2057 if (check_unsafe_error &&
2058 condition == _async_unsafe_access_error && !has_pending_exception()) {
2059 condition = _no_async_condition; // done
2060 switch (thread_state()) {
2061 case _thread_in_vm: {
2062 JavaThread* THREAD = this;
2063 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2064 }
2065 case _thread_in_native: {
2066 ThreadInVMfromNative tiv(this);
2067 JavaThread* THREAD = this;
2068 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2069 }
2070 case _thread_in_Java: {
2071 ThreadInVMfromJava tiv(this);
2072 JavaThread* THREAD = this;
2073 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2074 }
2075 default:
2076 ShouldNotReachHere();
2077 }
2078 }
2079
2080 assert(condition == _no_async_condition || has_pending_exception() ||
2081 (!check_unsafe_error && condition == _async_unsafe_access_error),
2082 "must have handled the async condition, if no exception");
2083 }
2084
2085 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2086 //
2087 // Check for pending external suspend. Internal suspend requests do
2088 // not use handle_special_runtime_exit_condition().
2089 // If JNIEnv proxies are allowed, don't self-suspend if the target
2090 // thread is not the current thread. In older versions of jdbx, jdbx
2091 // threads could call into the VM with another thread's JNIEnv so we
2092 // can be here operating on behalf of a suspended thread (4432884).
2093 bool do_self_suspend = is_external_suspend_with_lock();
2094 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2095 //
2096 // Because thread is external suspended the safepoint code will count
2097 // thread as at a safepoint. This can be odd because we can be here
2098 // as _thread_in_Java which would normally transition to _thread_blocked
2099 // at a safepoint. We would like to mark the thread as _thread_blocked
2100 // before calling java_suspend_self like all other callers of it but
2101 // we must then observe proper safepoint protocol. (We can't leave
2102 // _thread_blocked with a safepoint in progress). However we can be
2103 // here as _thread_in_native_trans so we can't use a normal transition
2104 // constructor/destructor pair because they assert on that type of
2105 // transition. We could do something like:
2106 //
2107 // JavaThreadState state = thread_state();
2108 // set_thread_state(_thread_in_vm);
2109 // {
2110 // ThreadBlockInVM tbivm(this);
2111 // java_suspend_self()
2112 // }
2113 // set_thread_state(_thread_in_vm_trans);
2114 // if (safepoint) block;
2115 // set_thread_state(state);
2116 //
2117 // but that is pretty messy. Instead we just go with the way the
2118 // code has worked before and note that this is the only path to
2119 // java_suspend_self that doesn't put the thread in _thread_blocked
2120 // mode.
2121
2122 frame_anchor()->make_walkable(this);
2123 java_suspend_self();
2124
2125 // We might be here for reasons in addition to the self-suspend request
2126 // so check for other async requests.
2127 }
2128
2129 if (check_asyncs) {
2130 check_and_handle_async_exceptions();
2131 }
2132 }
2133
2134 void JavaThread::send_thread_stop(oop java_throwable) {
2135 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2136 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2137 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2138
2139 // Do not throw asynchronous exceptions against the compiler thread
2140 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2141 if (is_Compiler_thread()) return;
2142
2143 {
2144 // Actually throw the Throwable against the target Thread - however
2145 // only if there is no thread death exception installed already.
2146 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2147 // If the topmost frame is a runtime stub, then we are calling into
2148 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2149 // must deoptimize the caller before continuing, as the compiled exception handler table
2150 // may not be valid
2151 if (has_last_Java_frame()) {
2152 frame f = last_frame();
2153 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2154 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2155 RegisterMap reg_map(this, UseBiasedLocking);
2156 frame compiled_frame = f.sender(®_map);
2157 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2158 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2159 }
2160 }
2161 }
2162
2163 // Set async. pending exception in thread.
2164 set_pending_async_exception(java_throwable);
2165
2166 if (TraceExceptions) {
2167 ResourceMark rm;
2168 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2169 }
2170 // for AbortVMOnException flag
2171 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2172 }
2173 }
2174
2175
2176 // Interrupt thread so it will wake up from a potential wait()
2177 Thread::interrupt(this);
2178 }
2179
2180 // External suspension mechanism.
2181 //
2182 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2183 // to any VM_locks and it is at a transition
2184 // Self-suspension will happen on the transition out of the vm.
2185 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2186 //
2187 // Guarantees on return:
2188 // + Target thread will not execute any new bytecode (that's why we need to
2189 // force a safepoint)
2190 // + Target thread will not enter any new monitors
2191 //
2192 void JavaThread::java_suspend() {
2193 { MutexLocker mu(Threads_lock);
2194 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2195 return;
2196 }
2197 }
2198
2199 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2200 if (!is_external_suspend()) {
2201 // a racing resume has cancelled us; bail out now
2202 return;
2203 }
2204
2205 // suspend is done
2206 uint32_t debug_bits = 0;
2207 // Warning: is_ext_suspend_completed() may temporarily drop the
2208 // SR_lock to allow the thread to reach a stable thread state if
2209 // it is currently in a transient thread state.
2210 if (is_ext_suspend_completed(false /* !called_by_wait */,
2211 SuspendRetryDelay, &debug_bits)) {
2212 return;
2213 }
2214 }
2215
2216 VM_ForceSafepoint vm_suspend;
2217 VMThread::execute(&vm_suspend);
2218 }
2219
2220 // Part II of external suspension.
2221 // A JavaThread self suspends when it detects a pending external suspend
2222 // request. This is usually on transitions. It is also done in places
2223 // where continuing to the next transition would surprise the caller,
2224 // e.g., monitor entry.
2225 //
2226 // Returns the number of times that the thread self-suspended.
2227 //
2228 // Note: DO NOT call java_suspend_self() when you just want to block current
2229 // thread. java_suspend_self() is the second stage of cooperative
2230 // suspension for external suspend requests and should only be used
2231 // to complete an external suspend request.
2232 //
2233 int JavaThread::java_suspend_self() {
2234 int ret = 0;
2235
2236 // we are in the process of exiting so don't suspend
2237 if (is_exiting()) {
2238 clear_external_suspend();
2239 return ret;
2240 }
2241
2242 assert(_anchor.walkable() ||
2243 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2244 "must have walkable stack");
2245
2246 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2247
2248 assert(!this->is_ext_suspended(),
2249 "a thread trying to self-suspend should not already be suspended");
2250
2251 if (this->is_suspend_equivalent()) {
2252 // If we are self-suspending as a result of the lifting of a
2253 // suspend equivalent condition, then the suspend_equivalent
2254 // flag is not cleared until we set the ext_suspended flag so
2255 // that wait_for_ext_suspend_completion() returns consistent
2256 // results.
2257 this->clear_suspend_equivalent();
2258 }
2259
2260 // A racing resume may have cancelled us before we grabbed SR_lock
2261 // above. Or another external suspend request could be waiting for us
2262 // by the time we return from SR_lock()->wait(). The thread
2263 // that requested the suspension may already be trying to walk our
2264 // stack and if we return now, we can change the stack out from under
2265 // it. This would be a "bad thing (TM)" and cause the stack walker
2266 // to crash. We stay self-suspended until there are no more pending
2267 // external suspend requests.
2268 while (is_external_suspend()) {
2269 ret++;
2270 this->set_ext_suspended();
2271
2272 // _ext_suspended flag is cleared by java_resume()
2273 while (is_ext_suspended()) {
2274 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2275 }
2276 }
2277
2278 return ret;
2279 }
2280
2281 #ifdef ASSERT
2282 // verify the JavaThread has not yet been published in the Threads::list, and
2283 // hence doesn't need protection from concurrent access at this stage
2284 void JavaThread::verify_not_published() {
2285 if (!Threads_lock->owned_by_self()) {
2286 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2287 assert(!Threads::includes(this),
2288 "java thread shouldn't have been published yet!");
2289 } else {
2290 assert(!Threads::includes(this),
2291 "java thread shouldn't have been published yet!");
2292 }
2293 }
2294 #endif
2295
2296 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2297 // progress or when _suspend_flags is non-zero.
2298 // Current thread needs to self-suspend if there is a suspend request and/or
2299 // block if a safepoint is in progress.
2300 // Async exception ISN'T checked.
2301 // Note only the ThreadInVMfromNative transition can call this function
2302 // directly and when thread state is _thread_in_native_trans
2303 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2304 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2305
2306 JavaThread *curJT = JavaThread::current();
2307 bool do_self_suspend = thread->is_external_suspend();
2308
2309 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2310
2311 // If JNIEnv proxies are allowed, don't self-suspend if the target
2312 // thread is not the current thread. In older versions of jdbx, jdbx
2313 // threads could call into the VM with another thread's JNIEnv so we
2314 // can be here operating on behalf of a suspended thread (4432884).
2315 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2316 JavaThreadState state = thread->thread_state();
2317
2318 // We mark this thread_blocked state as a suspend-equivalent so
2319 // that a caller to is_ext_suspend_completed() won't be confused.
2320 // The suspend-equivalent state is cleared by java_suspend_self().
2321 thread->set_suspend_equivalent();
2322
2323 // If the safepoint code sees the _thread_in_native_trans state, it will
2324 // wait until the thread changes to other thread state. There is no
2325 // guarantee on how soon we can obtain the SR_lock and complete the
2326 // self-suspend request. It would be a bad idea to let safepoint wait for
2327 // too long. Temporarily change the state to _thread_blocked to
2328 // let the VM thread know that this thread is ready for GC. The problem
2329 // of changing thread state is that safepoint could happen just after
2330 // java_suspend_self() returns after being resumed, and VM thread will
2331 // see the _thread_blocked state. We must check for safepoint
2332 // after restoring the state and make sure we won't leave while a safepoint
2333 // is in progress.
2334 thread->set_thread_state(_thread_blocked);
2335 thread->java_suspend_self();
2336 thread->set_thread_state(state);
2337 // Make sure new state is seen by VM thread
2338 if (os::is_MP()) {
2339 if (UseMembar) {
2340 // Force a fence between the write above and read below
2341 OrderAccess::fence();
2342 } else {
2343 // Must use this rather than serialization page in particular on Windows
2344 InterfaceSupport::serialize_memory(thread);
2345 }
2346 }
2347 }
2348
2349 if (SafepointSynchronize::do_call_back()) {
2350 // If we are safepointing, then block the caller which may not be
2351 // the same as the target thread (see above).
2352 SafepointSynchronize::block(curJT);
2353 }
2354
2355 if (thread->is_deopt_suspend()) {
2356 thread->clear_deopt_suspend();
2357 RegisterMap map(thread, false);
2358 frame f = thread->last_frame();
2359 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2360 f = f.sender(&map);
2361 }
2362 if (f.id() == thread->must_deopt_id()) {
2363 thread->clear_must_deopt_id();
2364 f.deoptimize(thread);
2365 } else {
2366 fatal("missed deoptimization!");
2367 }
2368 }
2369 }
2370
2371 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2372 // progress or when _suspend_flags is non-zero.
2373 // Current thread needs to self-suspend if there is a suspend request and/or
2374 // block if a safepoint is in progress.
2375 // Also check for pending async exception (not including unsafe access error).
2376 // Note only the native==>VM/Java barriers can call this function and when
2377 // thread state is _thread_in_native_trans.
2378 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2379 check_safepoint_and_suspend_for_native_trans(thread);
2380
2381 if (thread->has_async_exception()) {
2382 // We are in _thread_in_native_trans state, don't handle unsafe
2383 // access error since that may block.
2384 thread->check_and_handle_async_exceptions(false);
2385 }
2386 }
2387
2388 // This is a variant of the normal
2389 // check_special_condition_for_native_trans with slightly different
2390 // semantics for use by critical native wrappers. It does all the
2391 // normal checks but also performs the transition back into
2392 // thread_in_Java state. This is required so that critical natives
2393 // can potentially block and perform a GC if they are the last thread
2394 // exiting the GC_locker.
2395 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2396 check_special_condition_for_native_trans(thread);
2397
2398 // Finish the transition
2399 thread->set_thread_state(_thread_in_Java);
2400
2401 if (thread->do_critical_native_unlock()) {
2402 ThreadInVMfromJavaNoAsyncException tiv(thread);
2403 GC_locker::unlock_critical(thread);
2404 thread->clear_critical_native_unlock();
2405 }
2406 }
2407
2408 // We need to guarantee the Threads_lock here, since resumes are not
2409 // allowed during safepoint synchronization
2410 // Can only resume from an external suspension
2411 void JavaThread::java_resume() {
2412 assert_locked_or_safepoint(Threads_lock);
2413
2414 // Sanity check: thread is gone, has started exiting or the thread
2415 // was not externally suspended.
2416 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2417 return;
2418 }
2419
2420 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2421
2422 clear_external_suspend();
2423
2424 if (is_ext_suspended()) {
2425 clear_ext_suspended();
2426 SR_lock()->notify_all();
2427 }
2428 }
2429
2430 void JavaThread::create_stack_guard_pages() {
2431 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2432 address low_addr = stack_base() - stack_size();
2433 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2434
2435 int allocate = os::allocate_stack_guard_pages();
2436 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2437
2438 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2439 warning("Attempt to allocate stack guard pages failed.");
2440 return;
2441 }
2442
2443 if (os::guard_memory((char *) low_addr, len)) {
2444 _stack_guard_state = stack_guard_enabled;
2445 } else {
2446 warning("Attempt to protect stack guard pages failed.");
2447 if (os::uncommit_memory((char *) low_addr, len)) {
2448 warning("Attempt to deallocate stack guard pages failed.");
2449 }
2450 }
2451 }
2452
2453 void JavaThread::remove_stack_guard_pages() {
2454 assert(Thread::current() == this, "from different thread");
2455 if (_stack_guard_state == stack_guard_unused) return;
2456 address low_addr = stack_base() - stack_size();
2457 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2458
2459 if (os::allocate_stack_guard_pages()) {
2460 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2461 _stack_guard_state = stack_guard_unused;
2462 } else {
2463 warning("Attempt to deallocate stack guard pages failed.");
2464 }
2465 } else {
2466 if (_stack_guard_state == stack_guard_unused) return;
2467 if (os::unguard_memory((char *) low_addr, len)) {
2468 _stack_guard_state = stack_guard_unused;
2469 } else {
2470 warning("Attempt to unprotect stack guard pages failed.");
2471 }
2472 }
2473 }
2474
2475 void JavaThread::enable_stack_yellow_zone() {
2476 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2477 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2478
2479 // The base notation is from the stacks point of view, growing downward.
2480 // We need to adjust it to work correctly with guard_memory()
2481 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2482
2483 guarantee(base < stack_base(), "Error calculating stack yellow zone");
2484 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
2485
2486 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2487 _stack_guard_state = stack_guard_enabled;
2488 } else {
2489 warning("Attempt to guard stack yellow zone failed.");
2490 }
2491 enable_register_stack_guard();
2492 }
2493
2494 void JavaThread::disable_stack_yellow_zone() {
2495 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2496 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2497
2498 // Simply return if called for a thread that does not use guard pages.
2499 if (_stack_guard_state == stack_guard_unused) return;
2500
2501 // The base notation is from the stacks point of view, growing downward.
2502 // We need to adjust it to work correctly with guard_memory()
2503 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2504
2505 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2506 _stack_guard_state = stack_guard_yellow_disabled;
2507 } else {
2508 warning("Attempt to unguard stack yellow zone failed.");
2509 }
2510 disable_register_stack_guard();
2511 }
2512
2513 void JavaThread::enable_stack_red_zone() {
2514 // The base notation is from the stacks point of view, growing downward.
2515 // We need to adjust it to work correctly with guard_memory()
2516 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2517 address base = stack_red_zone_base() - stack_red_zone_size();
2518
2519 guarantee(base < stack_base(), "Error calculating stack red zone");
2520 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
2521
2522 if (!os::guard_memory((char *) base, stack_red_zone_size())) {
2523 warning("Attempt to guard stack red zone failed.");
2524 }
2525 }
2526
2527 void JavaThread::disable_stack_red_zone() {
2528 // The base notation is from the stacks point of view, growing downward.
2529 // We need to adjust it to work correctly with guard_memory()
2530 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2531 address base = stack_red_zone_base() - stack_red_zone_size();
2532 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2533 warning("Attempt to unguard stack red zone failed.");
2534 }
2535 }
2536
2537 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2538 // ignore is there is no stack
2539 if (!has_last_Java_frame()) return;
2540 // traverse the stack frames. Starts from top frame.
2541 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2542 frame* fr = fst.current();
2543 f(fr, fst.register_map());
2544 }
2545 }
2546
2547
2548 #ifndef PRODUCT
2549 // Deoptimization
2550 // Function for testing deoptimization
2551 void JavaThread::deoptimize() {
2552 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2553 StackFrameStream fst(this, UseBiasedLocking);
2554 bool deopt = false; // Dump stack only if a deopt actually happens.
2555 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2556 // Iterate over all frames in the thread and deoptimize
2557 for (; !fst.is_done(); fst.next()) {
2558 if (fst.current()->can_be_deoptimized()) {
2559
2560 if (only_at) {
2561 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2562 // consists of comma or carriage return separated numbers so
2563 // search for the current bci in that string.
2564 address pc = fst.current()->pc();
2565 nmethod* nm = (nmethod*) fst.current()->cb();
2566 ScopeDesc* sd = nm->scope_desc_at(pc);
2567 char buffer[8];
2568 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2569 size_t len = strlen(buffer);
2570 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2571 while (found != NULL) {
2572 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2573 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2574 // Check that the bci found is bracketed by terminators.
2575 break;
2576 }
2577 found = strstr(found + 1, buffer);
2578 }
2579 if (!found) {
2580 continue;
2581 }
2582 }
2583
2584 if (DebugDeoptimization && !deopt) {
2585 deopt = true; // One-time only print before deopt
2586 tty->print_cr("[BEFORE Deoptimization]");
2587 trace_frames();
2588 trace_stack();
2589 }
2590 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2591 }
2592 }
2593
2594 if (DebugDeoptimization && deopt) {
2595 tty->print_cr("[AFTER Deoptimization]");
2596 trace_frames();
2597 }
2598 }
2599
2600
2601 // Make zombies
2602 void JavaThread::make_zombies() {
2603 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2604 if (fst.current()->can_be_deoptimized()) {
2605 // it is a Java nmethod
2606 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2607 nm->make_not_entrant();
2608 }
2609 }
2610 }
2611 #endif // PRODUCT
2612
2613
2614 void JavaThread::deoptimized_wrt_marked_nmethods() {
2615 if (!has_last_Java_frame()) return;
2616 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2617 StackFrameStream fst(this, UseBiasedLocking);
2618 for (; !fst.is_done(); fst.next()) {
2619 if (fst.current()->should_be_deoptimized()) {
2620 if (LogCompilation && xtty != NULL) {
2621 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2622 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2623 this->name(), nm != NULL ? nm->compile_id() : -1);
2624 }
2625
2626 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2627 }
2628 }
2629 }
2630
2631
2632 // If the caller is a NamedThread, then remember, in the current scope,
2633 // the given JavaThread in its _processed_thread field.
2634 class RememberProcessedThread: public StackObj {
2635 NamedThread* _cur_thr;
2636 public:
2637 RememberProcessedThread(JavaThread* jthr) {
2638 Thread* thread = Thread::current();
2639 if (thread->is_Named_thread()) {
2640 _cur_thr = (NamedThread *)thread;
2641 _cur_thr->set_processed_thread(jthr);
2642 } else {
2643 _cur_thr = NULL;
2644 }
2645 }
2646
2647 ~RememberProcessedThread() {
2648 if (_cur_thr) {
2649 _cur_thr->set_processed_thread(NULL);
2650 }
2651 }
2652 };
2653
2654 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2655 // Verify that the deferred card marks have been flushed.
2656 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2657
2658 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2659 // since there may be more than one thread using each ThreadProfiler.
2660
2661 // Traverse the GCHandles
2662 Thread::oops_do(f, cld_f, cf);
2663
2664 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2665 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2666
2667 if (has_last_Java_frame()) {
2668 // Record JavaThread to GC thread
2669 RememberProcessedThread rpt(this);
2670
2671 // Traverse the privileged stack
2672 if (_privileged_stack_top != NULL) {
2673 _privileged_stack_top->oops_do(f);
2674 }
2675
2676 // traverse the registered growable array
2677 if (_array_for_gc != NULL) {
2678 for (int index = 0; index < _array_for_gc->length(); index++) {
2679 f->do_oop(_array_for_gc->adr_at(index));
2680 }
2681 }
2682
2683 // Traverse the monitor chunks
2684 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2685 chunk->oops_do(f);
2686 }
2687
2688 // Traverse the execution stack
2689 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2690 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2691 }
2692 }
2693
2694 // callee_target is never live across a gc point so NULL it here should
2695 // it still contain a methdOop.
2696
2697 set_callee_target(NULL);
2698
2699 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2700 // If we have deferred set_locals there might be oops waiting to be
2701 // written
2702 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2703 if (list != NULL) {
2704 for (int i = 0; i < list->length(); i++) {
2705 list->at(i)->oops_do(f);
2706 }
2707 }
2708
2709 // Traverse instance variables at the end since the GC may be moving things
2710 // around using this function
2711 f->do_oop((oop*) &_threadObj);
2712 f->do_oop((oop*) &_vm_result);
2713 f->do_oop((oop*) &_exception_oop);
2714 f->do_oop((oop*) &_pending_async_exception);
2715
2716 if (jvmti_thread_state() != NULL) {
2717 jvmti_thread_state()->oops_do(f);
2718 }
2719 }
2720
2721 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2722 Thread::nmethods_do(cf); // (super method is a no-op)
2723
2724 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
2725 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2726
2727 if (has_last_Java_frame()) {
2728 // Traverse the execution stack
2729 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2730 fst.current()->nmethods_do(cf);
2731 }
2732 }
2733 }
2734
2735 void JavaThread::metadata_do(void f(Metadata*)) {
2736 if (has_last_Java_frame()) {
2737 // Traverse the execution stack to call f() on the methods in the stack
2738 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2739 fst.current()->metadata_do(f);
2740 }
2741 } else if (is_Compiler_thread()) {
2742 // need to walk ciMetadata in current compile tasks to keep alive.
2743 CompilerThread* ct = (CompilerThread*)this;
2744 if (ct->env() != NULL) {
2745 ct->env()->metadata_do(f);
2746 }
2747 if (ct->task() != NULL) {
2748 ct->task()->metadata_do(f);
2749 }
2750 }
2751 }
2752
2753 // Printing
2754 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2755 switch (_thread_state) {
2756 case _thread_uninitialized: return "_thread_uninitialized";
2757 case _thread_new: return "_thread_new";
2758 case _thread_new_trans: return "_thread_new_trans";
2759 case _thread_in_native: return "_thread_in_native";
2760 case _thread_in_native_trans: return "_thread_in_native_trans";
2761 case _thread_in_vm: return "_thread_in_vm";
2762 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2763 case _thread_in_Java: return "_thread_in_Java";
2764 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2765 case _thread_blocked: return "_thread_blocked";
2766 case _thread_blocked_trans: return "_thread_blocked_trans";
2767 default: return "unknown thread state";
2768 }
2769 }
2770
2771 #ifndef PRODUCT
2772 void JavaThread::print_thread_state_on(outputStream *st) const {
2773 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2774 };
2775 void JavaThread::print_thread_state() const {
2776 print_thread_state_on(tty);
2777 }
2778 #endif // PRODUCT
2779
2780 // Called by Threads::print() for VM_PrintThreads operation
2781 void JavaThread::print_on(outputStream *st) const {
2782 st->print("\"%s\" ", get_thread_name());
2783 oop thread_oop = threadObj();
2784 if (thread_oop != NULL) {
2785 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2786 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2787 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2788 }
2789 Thread::print_on(st);
2790 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2791 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2792 if (thread_oop != NULL) {
2793 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2794 }
2795 #ifndef PRODUCT
2796 print_thread_state_on(st);
2797 _safepoint_state->print_on(st);
2798 #endif // PRODUCT
2799 }
2800
2801 // Called by fatal error handler. The difference between this and
2802 // JavaThread::print() is that we can't grab lock or allocate memory.
2803 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2804 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2805 oop thread_obj = threadObj();
2806 if (thread_obj != NULL) {
2807 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2808 }
2809 st->print(" [");
2810 st->print("%s", _get_thread_state_name(_thread_state));
2811 if (osthread()) {
2812 st->print(", id=%d", osthread()->thread_id());
2813 }
2814 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2815 _stack_base - _stack_size, _stack_base);
2816 st->print("]");
2817 return;
2818 }
2819
2820 // Verification
2821
2822 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2823
2824 void JavaThread::verify() {
2825 // Verify oops in the thread.
2826 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2827
2828 // Verify the stack frames.
2829 frames_do(frame_verify);
2830 }
2831
2832 // CR 6300358 (sub-CR 2137150)
2833 // Most callers of this method assume that it can't return NULL but a
2834 // thread may not have a name whilst it is in the process of attaching to
2835 // the VM - see CR 6412693, and there are places where a JavaThread can be
2836 // seen prior to having it's threadObj set (eg JNI attaching threads and
2837 // if vm exit occurs during initialization). These cases can all be accounted
2838 // for such that this method never returns NULL.
2839 const char* JavaThread::get_thread_name() const {
2840 #ifdef ASSERT
2841 // early safepoints can hit while current thread does not yet have TLS
2842 if (!SafepointSynchronize::is_at_safepoint()) {
2843 Thread *cur = Thread::current();
2844 if (!(cur->is_Java_thread() && cur == this)) {
2845 // Current JavaThreads are allowed to get their own name without
2846 // the Threads_lock.
2847 assert_locked_or_safepoint(Threads_lock);
2848 }
2849 }
2850 #endif // ASSERT
2851 return get_thread_name_string();
2852 }
2853
2854 // Returns a non-NULL representation of this thread's name, or a suitable
2855 // descriptive string if there is no set name
2856 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2857 const char* name_str;
2858 oop thread_obj = threadObj();
2859 if (thread_obj != NULL) {
2860 oop name = java_lang_Thread::name(thread_obj);
2861 if (name != NULL) {
2862 if (buf == NULL) {
2863 name_str = java_lang_String::as_utf8_string(name);
2864 } else {
2865 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
2866 }
2867 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2868 name_str = "<no-name - thread is attaching>";
2869 } else {
2870 name_str = Thread::name();
2871 }
2872 } else {
2873 name_str = Thread::name();
2874 }
2875 assert(name_str != NULL, "unexpected NULL thread name");
2876 return name_str;
2877 }
2878
2879
2880 const char* JavaThread::get_threadgroup_name() const {
2881 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2882 oop thread_obj = threadObj();
2883 if (thread_obj != NULL) {
2884 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2885 if (thread_group != NULL) {
2886 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2887 // ThreadGroup.name can be null
2888 if (name != NULL) {
2889 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2890 return str;
2891 }
2892 }
2893 }
2894 return NULL;
2895 }
2896
2897 const char* JavaThread::get_parent_name() const {
2898 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2899 oop thread_obj = threadObj();
2900 if (thread_obj != NULL) {
2901 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2902 if (thread_group != NULL) {
2903 oop parent = java_lang_ThreadGroup::parent(thread_group);
2904 if (parent != NULL) {
2905 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2906 // ThreadGroup.name can be null
2907 if (name != NULL) {
2908 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2909 return str;
2910 }
2911 }
2912 }
2913 }
2914 return NULL;
2915 }
2916
2917 ThreadPriority JavaThread::java_priority() const {
2918 oop thr_oop = threadObj();
2919 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2920 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2921 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2922 return priority;
2923 }
2924
2925 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2926
2927 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2928 // Link Java Thread object <-> C++ Thread
2929
2930 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2931 // and put it into a new Handle. The Handle "thread_oop" can then
2932 // be used to pass the C++ thread object to other methods.
2933
2934 // Set the Java level thread object (jthread) field of the
2935 // new thread (a JavaThread *) to C++ thread object using the
2936 // "thread_oop" handle.
2937
2938 // Set the thread field (a JavaThread *) of the
2939 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2940
2941 Handle thread_oop(Thread::current(),
2942 JNIHandles::resolve_non_null(jni_thread));
2943 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
2944 "must be initialized");
2945 set_threadObj(thread_oop());
2946 java_lang_Thread::set_thread(thread_oop(), this);
2947
2948 if (prio == NoPriority) {
2949 prio = java_lang_Thread::priority(thread_oop());
2950 assert(prio != NoPriority, "A valid priority should be present");
2951 }
2952
2953 // Push the Java priority down to the native thread; needs Threads_lock
2954 Thread::set_priority(this, prio);
2955
2956 prepare_ext();
2957
2958 // Add the new thread to the Threads list and set it in motion.
2959 // We must have threads lock in order to call Threads::add.
2960 // It is crucial that we do not block before the thread is
2961 // added to the Threads list for if a GC happens, then the java_thread oop
2962 // will not be visited by GC.
2963 Threads::add(this);
2964 }
2965
2966 oop JavaThread::current_park_blocker() {
2967 // Support for JSR-166 locks
2968 oop thread_oop = threadObj();
2969 if (thread_oop != NULL &&
2970 JDK_Version::current().supports_thread_park_blocker()) {
2971 return java_lang_Thread::park_blocker(thread_oop);
2972 }
2973 return NULL;
2974 }
2975
2976
2977 void JavaThread::print_stack_on(outputStream* st) {
2978 if (!has_last_Java_frame()) return;
2979 ResourceMark rm;
2980 HandleMark hm;
2981
2982 RegisterMap reg_map(this);
2983 vframe* start_vf = last_java_vframe(®_map);
2984 int count = 0;
2985 for (vframe* f = start_vf; f; f = f->sender()) {
2986 if (f->is_java_frame()) {
2987 javaVFrame* jvf = javaVFrame::cast(f);
2988 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2989
2990 // Print out lock information
2991 if (JavaMonitorsInStackTrace) {
2992 jvf->print_lock_info_on(st, count);
2993 }
2994 } else {
2995 // Ignore non-Java frames
2996 }
2997
2998 // Bail-out case for too deep stacks
2999 count++;
3000 if (MaxJavaStackTraceDepth == count) return;
3001 }
3002 }
3003
3004
3005 // JVMTI PopFrame support
3006 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3007 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3008 if (in_bytes(size_in_bytes) != 0) {
3009 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3010 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3011 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3012 }
3013 }
3014
3015 void* JavaThread::popframe_preserved_args() {
3016 return _popframe_preserved_args;
3017 }
3018
3019 ByteSize JavaThread::popframe_preserved_args_size() {
3020 return in_ByteSize(_popframe_preserved_args_size);
3021 }
3022
3023 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3024 int sz = in_bytes(popframe_preserved_args_size());
3025 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3026 return in_WordSize(sz / wordSize);
3027 }
3028
3029 void JavaThread::popframe_free_preserved_args() {
3030 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3031 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
3032 _popframe_preserved_args = NULL;
3033 _popframe_preserved_args_size = 0;
3034 }
3035
3036 #ifndef PRODUCT
3037
3038 void JavaThread::trace_frames() {
3039 tty->print_cr("[Describe stack]");
3040 int frame_no = 1;
3041 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3042 tty->print(" %d. ", frame_no++);
3043 fst.current()->print_value_on(tty, this);
3044 tty->cr();
3045 }
3046 }
3047
3048 class PrintAndVerifyOopClosure: public OopClosure {
3049 protected:
3050 template <class T> inline void do_oop_work(T* p) {
3051 oop obj = oopDesc::load_decode_heap_oop(p);
3052 if (obj == NULL) return;
3053 tty->print(INTPTR_FORMAT ": ", p);
3054 if (obj->is_oop_or_null()) {
3055 if (obj->is_objArray()) {
3056 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3057 } else {
3058 obj->print();
3059 }
3060 } else {
3061 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3062 }
3063 tty->cr();
3064 }
3065 public:
3066 virtual void do_oop(oop* p) { do_oop_work(p); }
3067 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3068 };
3069
3070
3071 static void oops_print(frame* f, const RegisterMap *map) {
3072 PrintAndVerifyOopClosure print;
3073 f->print_value();
3074 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3075 }
3076
3077 // Print our all the locations that contain oops and whether they are
3078 // valid or not. This useful when trying to find the oldest frame
3079 // where an oop has gone bad since the frame walk is from youngest to
3080 // oldest.
3081 void JavaThread::trace_oops() {
3082 tty->print_cr("[Trace oops]");
3083 frames_do(oops_print);
3084 }
3085
3086
3087 #ifdef ASSERT
3088 // Print or validate the layout of stack frames
3089 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3090 ResourceMark rm;
3091 PRESERVE_EXCEPTION_MARK;
3092 FrameValues values;
3093 int frame_no = 0;
3094 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3095 fst.current()->describe(values, ++frame_no);
3096 if (depth == frame_no) break;
3097 }
3098 if (validate_only) {
3099 values.validate();
3100 } else {
3101 tty->print_cr("[Describe stack layout]");
3102 values.print(this);
3103 }
3104 }
3105 #endif
3106
3107 void JavaThread::trace_stack_from(vframe* start_vf) {
3108 ResourceMark rm;
3109 int vframe_no = 1;
3110 for (vframe* f = start_vf; f; f = f->sender()) {
3111 if (f->is_java_frame()) {
3112 javaVFrame::cast(f)->print_activation(vframe_no++);
3113 } else {
3114 f->print();
3115 }
3116 if (vframe_no > StackPrintLimit) {
3117 tty->print_cr("...<more frames>...");
3118 return;
3119 }
3120 }
3121 }
3122
3123
3124 void JavaThread::trace_stack() {
3125 if (!has_last_Java_frame()) return;
3126 ResourceMark rm;
3127 HandleMark hm;
3128 RegisterMap reg_map(this);
3129 trace_stack_from(last_java_vframe(®_map));
3130 }
3131
3132
3133 #endif // PRODUCT
3134
3135
3136 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3137 assert(reg_map != NULL, "a map must be given");
3138 frame f = last_frame();
3139 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
3140 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3141 }
3142 return NULL;
3143 }
3144
3145
3146 Klass* JavaThread::security_get_caller_class(int depth) {
3147 vframeStream vfst(this);
3148 vfst.security_get_caller_frame(depth);
3149 if (!vfst.at_end()) {
3150 return vfst.method()->method_holder();
3151 }
3152 return NULL;
3153 }
3154
3155 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3156 assert(thread->is_Compiler_thread(), "must be compiler thread");
3157 CompileBroker::compiler_thread_loop();
3158 }
3159
3160 static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
3161 NMethodSweeper::sweeper_loop();
3162 }
3163
3164 // Create a CompilerThread
3165 CompilerThread::CompilerThread(CompileQueue* queue,
3166 CompilerCounters* counters)
3167 : JavaThread(&compiler_thread_entry) {
3168 _env = NULL;
3169 _log = NULL;
3170 _task = NULL;
3171 _queue = queue;
3172 _counters = counters;
3173 _buffer_blob = NULL;
3174 _compiler = NULL;
3175
3176 #ifndef PRODUCT
3177 _ideal_graph_printer = NULL;
3178 #endif
3179 }
3180
3181 // Create sweeper thread
3182 CodeCacheSweeperThread::CodeCacheSweeperThread()
3183 : JavaThread(&sweeper_thread_entry) {
3184 _scanned_nmethod = NULL;
3185 }
3186 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3187 JavaThread::oops_do(f, cld_f, cf);
3188 if (_scanned_nmethod != NULL && cf != NULL) {
3189 // Safepoints can occur when the sweeper is scanning an nmethod so
3190 // process it here to make sure it isn't unloaded in the middle of
3191 // a scan.
3192 cf->do_code_blob(_scanned_nmethod);
3193 }
3194 }
3195
3196
3197 // ======= Threads ========
3198
3199 // The Threads class links together all active threads, and provides
3200 // operations over all threads. It is protected by its own Mutex
3201 // lock, which is also used in other contexts to protect thread
3202 // operations from having the thread being operated on from exiting
3203 // and going away unexpectedly (e.g., safepoint synchronization)
3204
3205 JavaThread* Threads::_thread_list = NULL;
3206 int Threads::_number_of_threads = 0;
3207 int Threads::_number_of_non_daemon_threads = 0;
3208 int Threads::_return_code = 0;
3209 int Threads::_thread_claim_parity = 0;
3210 size_t JavaThread::_stack_size_at_create = 0;
3211 #ifdef ASSERT
3212 bool Threads::_vm_complete = false;
3213 #endif
3214
3215 // All JavaThreads
3216 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3217
3218 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3219 void Threads::threads_do(ThreadClosure* tc) {
3220 assert_locked_or_safepoint(Threads_lock);
3221 // ALL_JAVA_THREADS iterates through all JavaThreads
3222 ALL_JAVA_THREADS(p) {
3223 tc->do_thread(p);
3224 }
3225 // Someday we could have a table or list of all non-JavaThreads.
3226 // For now, just manually iterate through them.
3227 tc->do_thread(VMThread::vm_thread());
3228 Universe::heap()->gc_threads_do(tc);
3229 WatcherThread *wt = WatcherThread::watcher_thread();
3230 // Strictly speaking, the following NULL check isn't sufficient to make sure
3231 // the data for WatcherThread is still valid upon being examined. However,
3232 // considering that WatchThread terminates when the VM is on the way to
3233 // exit at safepoint, the chance of the above is extremely small. The right
3234 // way to prevent termination of WatcherThread would be to acquire
3235 // Terminator_lock, but we can't do that without violating the lock rank
3236 // checking in some cases.
3237 if (wt != NULL) {
3238 tc->do_thread(wt);
3239 }
3240
3241 // If CompilerThreads ever become non-JavaThreads, add them here
3242 }
3243
3244 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
3245 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3246
3247 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3248 create_vm_init_libraries();
3249 }
3250
3251 initialize_class(vmSymbols::java_lang_String(), CHECK);
3252
3253 // Initialize java_lang.System (needed before creating the thread)
3254 initialize_class(vmSymbols::java_lang_System(), CHECK);
3255 // The VM creates & returns objects of this class. Make sure it's initialized.
3256 initialize_class(vmSymbols::java_lang_Class(), CHECK);
3257 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
3258 Handle thread_group = create_initial_thread_group(CHECK);
3259 Universe::set_main_thread_group(thread_group());
3260 initialize_class(vmSymbols::java_lang_Thread(), CHECK);
3261 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
3262 main_thread->set_threadObj(thread_object);
3263 // Set thread status to running since main thread has
3264 // been started and running.
3265 java_lang_Thread::set_thread_status(thread_object,
3266 java_lang_Thread::RUNNABLE);
3267
3268 // The VM preresolves methods to these classes. Make sure that they get initialized
3269 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
3270 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
3271 call_initializeSystemClass(CHECK);
3272
3273 // get the Java runtime name after java.lang.System is initialized
3274 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3275 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3276
3277 // an instance of OutOfMemory exception has been allocated earlier
3278 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
3279 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
3280 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
3281 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
3282 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
3283 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
3284 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
3285 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
3286 }
3287
3288 void Threads::initialize_jsr292_core_classes(TRAPS) {
3289 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
3290 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
3291 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
3292 }
3293
3294 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3295 extern void JDK_Version_init();
3296
3297 // Preinitialize version info.
3298 VM_Version::early_initialize();
3299
3300 // Check version
3301 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3302
3303 // Initialize the output stream module
3304 ostream_init();
3305
3306 // Process java launcher properties.
3307 Arguments::process_sun_java_launcher_properties(args);
3308
3309 // Initialize the os module before using TLS
3310 os::init();
3311
3312 // Record VM creation timing statistics
3313 TraceVmCreationTime create_vm_timer;
3314 create_vm_timer.start();
3315
3316 // Initialize system properties.
3317 Arguments::init_system_properties();
3318
3319 // So that JDK version can be used as a discriminator when parsing arguments
3320 JDK_Version_init();
3321
3322 // Update/Initialize System properties after JDK version number is known
3323 Arguments::init_version_specific_system_properties();
3324
3325 // Make sure to initialize log configuration *before* parsing arguments
3326 LogConfiguration::initialize(create_vm_timer.begin_time());
3327
3328 // Parse arguments
3329 jint parse_result = Arguments::parse(args);
3330 if (parse_result != JNI_OK) return parse_result;
3331
3332 os::init_before_ergo();
3333
3334 jint ergo_result = Arguments::apply_ergo();
3335 if (ergo_result != JNI_OK) return ergo_result;
3336
3337 // Final check of all ranges after ergonomics which may change values.
3338 if (!CommandLineFlagRangeList::check_ranges()) {
3339 return JNI_EINVAL;
3340 }
3341
3342 // Final check of all 'AfterErgo' constraints after ergonomics which may change values.
3343 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
3344 if (!constraint_result) {
3345 return JNI_EINVAL;
3346 }
3347
3348 if (PauseAtStartup) {
3349 os::pause();
3350 }
3351
3352 HOTSPOT_VM_INIT_BEGIN();
3353
3354 // Timing (must come after argument parsing)
3355 TraceTime timer("Create VM", TraceStartupTime);
3356
3357 // Initialize the os module after parsing the args
3358 jint os_init_2_result = os::init_2();
3359 if (os_init_2_result != JNI_OK) return os_init_2_result;
3360
3361 jint adjust_after_os_result = Arguments::adjust_after_os();
3362 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3363
3364 // initialize TLS
3365 ThreadLocalStorage::init();
3366
3367 // Initialize output stream logging
3368 ostream_init_log();
3369
3370 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3371 // Must be before create_vm_init_agents()
3372 if (Arguments::init_libraries_at_startup()) {
3373 convert_vm_init_libraries_to_agents();
3374 }
3375
3376 // Launch -agentlib/-agentpath and converted -Xrun agents
3377 if (Arguments::init_agents_at_startup()) {
3378 create_vm_init_agents();
3379 }
3380
3381 // Initialize Threads state
3382 _thread_list = NULL;
3383 _number_of_threads = 0;
3384 _number_of_non_daemon_threads = 0;
3385
3386 // Initialize global data structures and create system classes in heap
3387 vm_init_globals();
3388
3389 // Attach the main thread to this os thread
3390 JavaThread* main_thread = new JavaThread();
3391 main_thread->set_thread_state(_thread_in_vm);
3392 // must do this before set_active_handles and initialize_thread_local_storage
3393 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3394 // change the stack size recorded here to one based on the java thread
3395 // stacksize. This adjusted size is what is used to figure the placement
3396 // of the guard pages.
3397 main_thread->record_stack_base_and_size();
3398 main_thread->initialize_thread_local_storage();
3399
3400 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3401
3402 if (!main_thread->set_as_starting_thread()) {
3403 vm_shutdown_during_initialization(
3404 "Failed necessary internal allocation. Out of swap space");
3405 delete main_thread;
3406 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3407 return JNI_ENOMEM;
3408 }
3409
3410 // Enable guard page *after* os::create_main_thread(), otherwise it would
3411 // crash Linux VM, see notes in os_linux.cpp.
3412 main_thread->create_stack_guard_pages();
3413
3414 // Initialize Java-Level synchronization subsystem
3415 ObjectMonitor::Initialize();
3416
3417 // Initialize global modules
3418 jint status = init_globals();
3419 if (status != JNI_OK) {
3420 delete main_thread;
3421 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3422 return status;
3423 }
3424
3425 // Should be done after the heap is fully created
3426 main_thread->cache_global_variables();
3427
3428 HandleMark hm;
3429
3430 { MutexLocker mu(Threads_lock);
3431 Threads::add(main_thread);
3432 }
3433
3434 // Any JVMTI raw monitors entered in onload will transition into
3435 // real raw monitor. VM is setup enough here for raw monitor enter.
3436 JvmtiExport::transition_pending_onload_raw_monitors();
3437
3438 // Create the VMThread
3439 { TraceTime timer("Start VMThread", TraceStartupTime);
3440 VMThread::create();
3441 Thread* vmthread = VMThread::vm_thread();
3442
3443 if (!os::create_thread(vmthread, os::vm_thread)) {
3444 vm_exit_during_initialization("Cannot create VM thread. "
3445 "Out of system resources.");
3446 }
3447
3448 // Wait for the VM thread to become ready, and VMThread::run to initialize
3449 // Monitors can have spurious returns, must always check another state flag
3450 {
3451 MutexLocker ml(Notify_lock);
3452 os::start_thread(vmthread);
3453 while (vmthread->active_handles() == NULL) {
3454 Notify_lock->wait();
3455 }
3456 }
3457 }
3458
3459 assert(Universe::is_fully_initialized(), "not initialized");
3460 if (VerifyDuringStartup) {
3461 // Make sure we're starting with a clean slate.
3462 VM_Verify verify_op;
3463 VMThread::execute(&verify_op);
3464 }
3465
3466 Thread* THREAD = Thread::current();
3467
3468 // At this point, the Universe is initialized, but we have not executed
3469 // any byte code. Now is a good time (the only time) to dump out the
3470 // internal state of the JVM for sharing.
3471 if (DumpSharedSpaces) {
3472 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
3473 ShouldNotReachHere();
3474 }
3475
3476 // Always call even when there are not JVMTI environments yet, since environments
3477 // may be attached late and JVMTI must track phases of VM execution
3478 JvmtiExport::enter_start_phase();
3479
3480 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3481 JvmtiExport::post_vm_start();
3482
3483 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
3484
3485 // We need this for ClassDataSharing - the initial vm.info property is set
3486 // with the default value of CDS "sharing" which may be reset through
3487 // command line options.
3488 reset_vm_info_property(CHECK_JNI_ERR);
3489
3490 quicken_jni_functions();
3491
3492 // Must be run after init_ft which initializes ft_enabled
3493 if (TRACE_INITIALIZE() != JNI_OK) {
3494 vm_exit_during_initialization("Failed to initialize tracing backend");
3495 }
3496
3497 // Set flag that basic initialization has completed. Used by exceptions and various
3498 // debug stuff, that does not work until all basic classes have been initialized.
3499 set_init_completed();
3500
3501 LogConfiguration::post_initialize();
3502 Metaspace::post_initialize();
3503
3504 HOTSPOT_VM_INIT_END();
3505
3506 // record VM initialization completion time
3507 #if INCLUDE_MANAGEMENT
3508 Management::record_vm_init_completed();
3509 #endif // INCLUDE_MANAGEMENT
3510
3511 // Compute system loader. Note that this has to occur after set_init_completed, since
3512 // valid exceptions may be thrown in the process.
3513 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3514 // set_init_completed has just been called, causing exceptions not to be shortcut
3515 // anymore. We call vm_exit_during_initialization directly instead.
3516 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR);
3517
3518 #if INCLUDE_ALL_GCS
3519 // Support for ConcurrentMarkSweep. This should be cleaned up
3520 // and better encapsulated. The ugly nested if test would go away
3521 // once things are properly refactored. XXX YSR
3522 if (UseConcMarkSweepGC || UseG1GC) {
3523 if (UseConcMarkSweepGC) {
3524 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3525 } else {
3526 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR);
3527 }
3528 }
3529 #endif // INCLUDE_ALL_GCS
3530
3531 // Always call even when there are not JVMTI environments yet, since environments
3532 // may be attached late and JVMTI must track phases of VM execution
3533 JvmtiExport::enter_live_phase();
3534
3535 // Signal Dispatcher needs to be started before VMInit event is posted
3536 os::signal_init();
3537
3538 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3539 if (!DisableAttachMechanism) {
3540 AttachListener::vm_start();
3541 if (StartAttachListener || AttachListener::init_at_startup()) {
3542 AttachListener::init();
3543 }
3544 }
3545
3546 // Launch -Xrun agents
3547 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3548 // back-end can launch with -Xdebug -Xrunjdwp.
3549 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3550 create_vm_init_libraries();
3551 }
3552
3553 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3554 JvmtiExport::post_vm_initialized();
3555
3556 if (TRACE_START() != JNI_OK) {
3557 vm_exit_during_initialization("Failed to start tracing backend.");
3558 }
3559
3560 if (CleanChunkPoolAsync) {
3561 Chunk::start_chunk_pool_cleaner_task();
3562 }
3563
3564 // initialize compiler(s)
3565 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3566 CompileBroker::compilation_init();
3567 #endif
3568
3569 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3570 // It is done after compilers are initialized, because otherwise compilations of
3571 // signature polymorphic MH intrinsics can be missed
3572 // (see SystemDictionary::find_method_handle_intrinsic).
3573 initialize_jsr292_core_classes(CHECK_JNI_ERR);
3574
3575 #if INCLUDE_MANAGEMENT
3576 Management::initialize(THREAD);
3577
3578 if (HAS_PENDING_EXCEPTION) {
3579 // management agent fails to start possibly due to
3580 // configuration problem and is responsible for printing
3581 // stack trace if appropriate. Simply exit VM.
3582 vm_exit(1);
3583 }
3584 #endif // INCLUDE_MANAGEMENT
3585
3586 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3587 if (MemProfiling) MemProfiler::engage();
3588 StatSampler::engage();
3589 if (CheckJNICalls) JniPeriodicChecker::engage();
3590
3591 BiasedLocking::init();
3592
3593 #if INCLUDE_RTM_OPT
3594 RTMLockingCounters::init();
3595 #endif
3596
3597 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3598 call_postVMInitHook(THREAD);
3599 // The Java side of PostVMInitHook.run must deal with all
3600 // exceptions and provide means of diagnosis.
3601 if (HAS_PENDING_EXCEPTION) {
3602 CLEAR_PENDING_EXCEPTION;
3603 }
3604 }
3605
3606 {
3607 MutexLocker ml(PeriodicTask_lock);
3608 // Make sure the WatcherThread can be started by WatcherThread::start()
3609 // or by dynamic enrollment.
3610 WatcherThread::make_startable();
3611 // Start up the WatcherThread if there are any periodic tasks
3612 // NOTE: All PeriodicTasks should be registered by now. If they
3613 // aren't, late joiners might appear to start slowly (we might
3614 // take a while to process their first tick).
3615 if (PeriodicTask::num_tasks() > 0) {
3616 WatcherThread::start();
3617 }
3618 }
3619
3620 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM);
3621
3622 create_vm_timer.end();
3623 #ifdef ASSERT
3624 _vm_complete = true;
3625 #endif
3626 return JNI_OK;
3627 }
3628
3629 // type for the Agent_OnLoad and JVM_OnLoad entry points
3630 extern "C" {
3631 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3632 }
3633 // Find a command line agent library and return its entry point for
3634 // -agentlib: -agentpath: -Xrun
3635 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3636 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
3637 const char *on_load_symbols[],
3638 size_t num_symbol_entries) {
3639 OnLoadEntry_t on_load_entry = NULL;
3640 void *library = NULL;
3641
3642 if (!agent->valid()) {
3643 char buffer[JVM_MAXPATHLEN];
3644 char ebuf[1024] = "";
3645 const char *name = agent->name();
3646 const char *msg = "Could not find agent library ";
3647
3648 // First check to see if agent is statically linked into executable
3649 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3650 library = agent->os_lib();
3651 } else if (agent->is_absolute_path()) {
3652 library = os::dll_load(name, ebuf, sizeof ebuf);
3653 if (library == NULL) {
3654 const char *sub_msg = " in absolute path, with error: ";
3655 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3656 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3657 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3658 // If we can't find the agent, exit.
3659 vm_exit_during_initialization(buf, NULL);
3660 FREE_C_HEAP_ARRAY(char, buf);
3661 }
3662 } else {
3663 // Try to load the agent from the standard dll directory
3664 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3665 name)) {
3666 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3667 }
3668 if (library == NULL) { // Try the local directory
3669 char ns[1] = {0};
3670 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3671 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3672 }
3673 if (library == NULL) {
3674 const char *sub_msg = " on the library path, with error: ";
3675 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3676 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3677 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3678 // If we can't find the agent, exit.
3679 vm_exit_during_initialization(buf, NULL);
3680 FREE_C_HEAP_ARRAY(char, buf);
3681 }
3682 }
3683 }
3684 agent->set_os_lib(library);
3685 agent->set_valid();
3686 }
3687
3688 // Find the OnLoad function.
3689 on_load_entry =
3690 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3691 false,
3692 on_load_symbols,
3693 num_symbol_entries));
3694 return on_load_entry;
3695 }
3696
3697 // Find the JVM_OnLoad entry point
3698 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3699 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3700 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3701 }
3702
3703 // Find the Agent_OnLoad entry point
3704 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3705 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3706 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3707 }
3708
3709 // For backwards compatibility with -Xrun
3710 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3711 // treated like -agentpath:
3712 // Must be called before agent libraries are created
3713 void Threads::convert_vm_init_libraries_to_agents() {
3714 AgentLibrary* agent;
3715 AgentLibrary* next;
3716
3717 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3718 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3719 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3720
3721 // If there is an JVM_OnLoad function it will get called later,
3722 // otherwise see if there is an Agent_OnLoad
3723 if (on_load_entry == NULL) {
3724 on_load_entry = lookup_agent_on_load(agent);
3725 if (on_load_entry != NULL) {
3726 // switch it to the agent list -- so that Agent_OnLoad will be called,
3727 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3728 Arguments::convert_library_to_agent(agent);
3729 } else {
3730 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3731 }
3732 }
3733 }
3734 }
3735
3736 // Create agents for -agentlib: -agentpath: and converted -Xrun
3737 // Invokes Agent_OnLoad
3738 // Called very early -- before JavaThreads exist
3739 void Threads::create_vm_init_agents() {
3740 extern struct JavaVM_ main_vm;
3741 AgentLibrary* agent;
3742
3743 JvmtiExport::enter_onload_phase();
3744
3745 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3746 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3747
3748 if (on_load_entry != NULL) {
3749 // Invoke the Agent_OnLoad function
3750 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3751 if (err != JNI_OK) {
3752 vm_exit_during_initialization("agent library failed to init", agent->name());
3753 }
3754 } else {
3755 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3756 }
3757 }
3758 JvmtiExport::enter_primordial_phase();
3759 }
3760
3761 extern "C" {
3762 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3763 }
3764
3765 void Threads::shutdown_vm_agents() {
3766 // Send any Agent_OnUnload notifications
3767 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3768 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3769 extern struct JavaVM_ main_vm;
3770 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3771
3772 // Find the Agent_OnUnload function.
3773 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3774 os::find_agent_function(agent,
3775 false,
3776 on_unload_symbols,
3777 num_symbol_entries));
3778
3779 // Invoke the Agent_OnUnload function
3780 if (unload_entry != NULL) {
3781 JavaThread* thread = JavaThread::current();
3782 ThreadToNativeFromVM ttn(thread);
3783 HandleMark hm(thread);
3784 (*unload_entry)(&main_vm);
3785 }
3786 }
3787 }
3788
3789 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3790 // Invokes JVM_OnLoad
3791 void Threads::create_vm_init_libraries() {
3792 extern struct JavaVM_ main_vm;
3793 AgentLibrary* agent;
3794
3795 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3796 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3797
3798 if (on_load_entry != NULL) {
3799 // Invoke the JVM_OnLoad function
3800 JavaThread* thread = JavaThread::current();
3801 ThreadToNativeFromVM ttn(thread);
3802 HandleMark hm(thread);
3803 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3804 if (err != JNI_OK) {
3805 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3806 }
3807 } else {
3808 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3809 }
3810 }
3811 }
3812
3813 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3814 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3815
3816 JavaThread* java_thread = NULL;
3817 // Sequential search for now. Need to do better optimization later.
3818 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3819 oop tobj = thread->threadObj();
3820 if (!thread->is_exiting() &&
3821 tobj != NULL &&
3822 java_tid == java_lang_Thread::thread_id(tobj)) {
3823 java_thread = thread;
3824 break;
3825 }
3826 }
3827 return java_thread;
3828 }
3829
3830
3831 // Last thread running calls java.lang.Shutdown.shutdown()
3832 void JavaThread::invoke_shutdown_hooks() {
3833 HandleMark hm(this);
3834
3835 // We could get here with a pending exception, if so clear it now.
3836 if (this->has_pending_exception()) {
3837 this->clear_pending_exception();
3838 }
3839
3840 EXCEPTION_MARK;
3841 Klass* k =
3842 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3843 THREAD);
3844 if (k != NULL) {
3845 // SystemDictionary::resolve_or_null will return null if there was
3846 // an exception. If we cannot load the Shutdown class, just don't
3847 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3848 // and finalizers (if runFinalizersOnExit is set) won't be run.
3849 // Note that if a shutdown hook was registered or runFinalizersOnExit
3850 // was called, the Shutdown class would have already been loaded
3851 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3852 instanceKlassHandle shutdown_klass (THREAD, k);
3853 JavaValue result(T_VOID);
3854 JavaCalls::call_static(&result,
3855 shutdown_klass,
3856 vmSymbols::shutdown_method_name(),
3857 vmSymbols::void_method_signature(),
3858 THREAD);
3859 }
3860 CLEAR_PENDING_EXCEPTION;
3861 }
3862
3863 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3864 // the program falls off the end of main(). Another VM exit path is through
3865 // vm_exit() when the program calls System.exit() to return a value or when
3866 // there is a serious error in VM. The two shutdown paths are not exactly
3867 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3868 // and VM_Exit op at VM level.
3869 //
3870 // Shutdown sequence:
3871 // + Shutdown native memory tracking if it is on
3872 // + Wait until we are the last non-daemon thread to execute
3873 // <-- every thing is still working at this moment -->
3874 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3875 // shutdown hooks, run finalizers if finalization-on-exit
3876 // + Call before_exit(), prepare for VM exit
3877 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3878 // currently the only user of this mechanism is File.deleteOnExit())
3879 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3880 // post thread end and vm death events to JVMTI,
3881 // stop signal thread
3882 // + Call JavaThread::exit(), it will:
3883 // > release JNI handle blocks, remove stack guard pages
3884 // > remove this thread from Threads list
3885 // <-- no more Java code from this thread after this point -->
3886 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3887 // the compiler threads at safepoint
3888 // <-- do not use anything that could get blocked by Safepoint -->
3889 // + Disable tracing at JNI/JVM barriers
3890 // + Set _vm_exited flag for threads that are still running native code
3891 // + Delete this thread
3892 // + Call exit_globals()
3893 // > deletes tty
3894 // > deletes PerfMemory resources
3895 // + Return to caller
3896
3897 bool Threads::destroy_vm() {
3898 JavaThread* thread = JavaThread::current();
3899
3900 #ifdef ASSERT
3901 _vm_complete = false;
3902 #endif
3903 // Wait until we are the last non-daemon thread to execute
3904 { MutexLocker nu(Threads_lock);
3905 while (Threads::number_of_non_daemon_threads() > 1)
3906 // This wait should make safepoint checks, wait without a timeout,
3907 // and wait as a suspend-equivalent condition.
3908 //
3909 // Note: If the FlatProfiler is running and this thread is waiting
3910 // for another non-daemon thread to finish, then the FlatProfiler
3911 // is waiting for the external suspend request on this thread to
3912 // complete. wait_for_ext_suspend_completion() will eventually
3913 // timeout, but that takes time. Making this wait a suspend-
3914 // equivalent condition solves that timeout problem.
3915 //
3916 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3917 Mutex::_as_suspend_equivalent_flag);
3918 }
3919
3920 // Hang forever on exit if we are reporting an error.
3921 if (ShowMessageBoxOnError && is_error_reported()) {
3922 os::infinite_sleep();
3923 }
3924 os::wait_for_keypress_at_exit();
3925
3926 // run Java level shutdown hooks
3927 thread->invoke_shutdown_hooks();
3928
3929 before_exit(thread);
3930
3931 thread->exit(true);
3932
3933 // Stop VM thread.
3934 {
3935 // 4945125 The vm thread comes to a safepoint during exit.
3936 // GC vm_operations can get caught at the safepoint, and the
3937 // heap is unparseable if they are caught. Grab the Heap_lock
3938 // to prevent this. The GC vm_operations will not be able to
3939 // queue until after the vm thread is dead. After this point,
3940 // we'll never emerge out of the safepoint before the VM exits.
3941
3942 MutexLocker ml(Heap_lock);
3943
3944 VMThread::wait_for_vm_thread_exit();
3945 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3946 VMThread::destroy();
3947 }
3948
3949 // clean up ideal graph printers
3950 #if defined(COMPILER2) && !defined(PRODUCT)
3951 IdealGraphPrinter::clean_up();
3952 #endif
3953
3954 // Now, all Java threads are gone except daemon threads. Daemon threads
3955 // running Java code or in VM are stopped by the Safepoint. However,
3956 // daemon threads executing native code are still running. But they
3957 // will be stopped at native=>Java/VM barriers. Note that we can't
3958 // simply kill or suspend them, as it is inherently deadlock-prone.
3959
3960 #ifndef PRODUCT
3961 // disable function tracing at JNI/JVM barriers
3962 TraceJNICalls = false;
3963 TraceJVMCalls = false;
3964 TraceRuntimeCalls = false;
3965 #endif
3966
3967 VM_Exit::set_vm_exited();
3968
3969 notify_vm_shutdown();
3970
3971 delete thread;
3972
3973 // exit_globals() will delete tty
3974 exit_globals();
3975
3976 LogConfiguration::finalize();
3977
3978 return true;
3979 }
3980
3981
3982 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3983 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3984 return is_supported_jni_version(version);
3985 }
3986
3987
3988 jboolean Threads::is_supported_jni_version(jint version) {
3989 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3990 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3991 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3992 if (version == JNI_VERSION_1_8) return JNI_TRUE;
3993 return JNI_FALSE;
3994 }
3995
3996
3997 void Threads::add(JavaThread* p, bool force_daemon) {
3998 // The threads lock must be owned at this point
3999 assert_locked_or_safepoint(Threads_lock);
4000
4001 // See the comment for this method in thread.hpp for its purpose and
4002 // why it is called here.
4003 p->initialize_queues();
4004 p->set_next(_thread_list);
4005 _thread_list = p;
4006 _number_of_threads++;
4007 oop threadObj = p->threadObj();
4008 bool daemon = true;
4009 // Bootstrapping problem: threadObj can be null for initial
4010 // JavaThread (or for threads attached via JNI)
4011 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4012 _number_of_non_daemon_threads++;
4013 daemon = false;
4014 }
4015
4016 ThreadService::add_thread(p, daemon);
4017
4018 // Possible GC point.
4019 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4020 }
4021
4022 void Threads::remove(JavaThread* p) {
4023 // Extra scope needed for Thread_lock, so we can check
4024 // that we do not remove thread without safepoint code notice
4025 { MutexLocker ml(Threads_lock);
4026
4027 assert(includes(p), "p must be present");
4028
4029 JavaThread* current = _thread_list;
4030 JavaThread* prev = NULL;
4031
4032 while (current != p) {
4033 prev = current;
4034 current = current->next();
4035 }
4036
4037 if (prev) {
4038 prev->set_next(current->next());
4039 } else {
4040 _thread_list = p->next();
4041 }
4042 _number_of_threads--;
4043 oop threadObj = p->threadObj();
4044 bool daemon = true;
4045 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4046 _number_of_non_daemon_threads--;
4047 daemon = false;
4048
4049 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4050 // on destroy_vm will wake up.
4051 if (number_of_non_daemon_threads() == 1) {
4052 Threads_lock->notify_all();
4053 }
4054 }
4055 ThreadService::remove_thread(p, daemon);
4056
4057 // Make sure that safepoint code disregard this thread. This is needed since
4058 // the thread might mess around with locks after this point. This can cause it
4059 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4060 // of this thread since it is removed from the queue.
4061 p->set_terminated_value();
4062 } // unlock Threads_lock
4063
4064 // Since Events::log uses a lock, we grab it outside the Threads_lock
4065 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4066 }
4067
4068 // Threads_lock must be held when this is called (or must be called during a safepoint)
4069 bool Threads::includes(JavaThread* p) {
4070 assert(Threads_lock->is_locked(), "sanity check");
4071 ALL_JAVA_THREADS(q) {
4072 if (q == p) {
4073 return true;
4074 }
4075 }
4076 return false;
4077 }
4078
4079 // Operations on the Threads list for GC. These are not explicitly locked,
4080 // but the garbage collector must provide a safe context for them to run.
4081 // In particular, these things should never be called when the Threads_lock
4082 // is held by some other thread. (Note: the Safepoint abstraction also
4083 // uses the Threads_lock to guarantee this property. It also makes sure that
4084 // all threads gets blocked when exiting or starting).
4085
4086 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4087 ALL_JAVA_THREADS(p) {
4088 p->oops_do(f, cld_f, cf);
4089 }
4090 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4091 }
4092
4093 void Threads::change_thread_claim_parity() {
4094 // Set the new claim parity.
4095 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
4096 "Not in range.");
4097 _thread_claim_parity++;
4098 if (_thread_claim_parity == 3) _thread_claim_parity = 1;
4099 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
4100 "Not in range.");
4101 }
4102
4103 #ifdef ASSERT
4104 void Threads::assert_all_threads_claimed() {
4105 ALL_JAVA_THREADS(p) {
4106 const int thread_parity = p->oops_do_parity();
4107 assert((thread_parity == _thread_claim_parity),
4108 err_msg("Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity));
4109 }
4110 }
4111 #endif // ASSERT
4112
4113 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4114 int cp = Threads::thread_claim_parity();
4115 ALL_JAVA_THREADS(p) {
4116 if (p->claim_oops_do(is_par, cp)) {
4117 p->oops_do(f, cld_f, cf);
4118 }
4119 }
4120 VMThread* vmt = VMThread::vm_thread();
4121 if (vmt->claim_oops_do(is_par, cp)) {
4122 vmt->oops_do(f, cld_f, cf);
4123 }
4124 }
4125
4126 #if INCLUDE_ALL_GCS
4127 // Used by ParallelScavenge
4128 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4129 ALL_JAVA_THREADS(p) {
4130 q->enqueue(new ThreadRootsTask(p));
4131 }
4132 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4133 }
4134
4135 // Used by Parallel Old
4136 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4137 ALL_JAVA_THREADS(p) {
4138 q->enqueue(new ThreadRootsMarkingTask(p));
4139 }
4140 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4141 }
4142 #endif // INCLUDE_ALL_GCS
4143
4144 void Threads::nmethods_do(CodeBlobClosure* cf) {
4145 ALL_JAVA_THREADS(p) {
4146 p->nmethods_do(cf);
4147 }
4148 VMThread::vm_thread()->nmethods_do(cf);
4149 }
4150
4151 void Threads::metadata_do(void f(Metadata*)) {
4152 ALL_JAVA_THREADS(p) {
4153 p->metadata_do(f);
4154 }
4155 }
4156
4157 class ThreadHandlesClosure : public ThreadClosure {
4158 void (*_f)(Metadata*);
4159 public:
4160 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
4161 virtual void do_thread(Thread* thread) {
4162 thread->metadata_handles_do(_f);
4163 }
4164 };
4165
4166 void Threads::metadata_handles_do(void f(Metadata*)) {
4167 // Only walk the Handles in Thread.
4168 ThreadHandlesClosure handles_closure(f);
4169 threads_do(&handles_closure);
4170 }
4171
4172 void Threads::deoptimized_wrt_marked_nmethods() {
4173 ALL_JAVA_THREADS(p) {
4174 p->deoptimized_wrt_marked_nmethods();
4175 }
4176 }
4177
4178
4179 // Get count Java threads that are waiting to enter the specified monitor.
4180 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4181 address monitor,
4182 bool doLock) {
4183 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4184 "must grab Threads_lock or be at safepoint");
4185 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4186
4187 int i = 0;
4188 {
4189 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4190 ALL_JAVA_THREADS(p) {
4191 if (p->is_Compiler_thread()) continue;
4192
4193 address pending = (address)p->current_pending_monitor();
4194 if (pending == monitor) { // found a match
4195 if (i < count) result->append(p); // save the first count matches
4196 i++;
4197 }
4198 }
4199 }
4200 return result;
4201 }
4202
4203
4204 JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
4205 bool doLock) {
4206 assert(doLock ||
4207 Threads_lock->owned_by_self() ||
4208 SafepointSynchronize::is_at_safepoint(),
4209 "must grab Threads_lock or be at safepoint");
4210
4211 // NULL owner means not locked so we can skip the search
4212 if (owner == NULL) return NULL;
4213
4214 {
4215 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4216 ALL_JAVA_THREADS(p) {
4217 // first, see if owner is the address of a Java thread
4218 if (owner == (address)p) return p;
4219 }
4220 }
4221 // Cannot assert on lack of success here since this function may be
4222 // used by code that is trying to report useful problem information
4223 // like deadlock detection.
4224 if (UseHeavyMonitors) return NULL;
4225
4226 // If we didn't find a matching Java thread and we didn't force use of
4227 // heavyweight monitors, then the owner is the stack address of the
4228 // Lock Word in the owning Java thread's stack.
4229 //
4230 JavaThread* the_owner = NULL;
4231 {
4232 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4233 ALL_JAVA_THREADS(q) {
4234 if (q->is_lock_owned(owner)) {
4235 the_owner = q;
4236 break;
4237 }
4238 }
4239 }
4240 // cannot assert on lack of success here; see above comment
4241 return the_owner;
4242 }
4243
4244 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4245 void Threads::print_on(outputStream* st, bool print_stacks,
4246 bool internal_format, bool print_concurrent_locks) {
4247 char buf[32];
4248 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4249
4250 st->print_cr("Full thread dump %s (%s %s):",
4251 Abstract_VM_Version::vm_name(),
4252 Abstract_VM_Version::vm_release(),
4253 Abstract_VM_Version::vm_info_string());
4254 st->cr();
4255
4256 #if INCLUDE_SERVICES
4257 // Dump concurrent locks
4258 ConcurrentLocksDump concurrent_locks;
4259 if (print_concurrent_locks) {
4260 concurrent_locks.dump_at_safepoint();
4261 }
4262 #endif // INCLUDE_SERVICES
4263
4264 ALL_JAVA_THREADS(p) {
4265 ResourceMark rm;
4266 p->print_on(st);
4267 if (print_stacks) {
4268 if (internal_format) {
4269 p->trace_stack();
4270 } else {
4271 p->print_stack_on(st);
4272 }
4273 }
4274 st->cr();
4275 #if INCLUDE_SERVICES
4276 if (print_concurrent_locks) {
4277 concurrent_locks.print_locks_on(p, st);
4278 }
4279 #endif // INCLUDE_SERVICES
4280 }
4281
4282 VMThread::vm_thread()->print_on(st);
4283 st->cr();
4284 Universe::heap()->print_gc_threads_on(st);
4285 WatcherThread* wt = WatcherThread::watcher_thread();
4286 if (wt != NULL) {
4287 wt->print_on(st);
4288 st->cr();
4289 }
4290 CompileBroker::print_compiler_threads_on(st);
4291 st->flush();
4292 }
4293
4294 // Threads::print_on_error() is called by fatal error handler. It's possible
4295 // that VM is not at safepoint and/or current thread is inside signal handler.
4296 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4297 // memory (even in resource area), it might deadlock the error handler.
4298 void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
4299 int buflen) {
4300 bool found_current = false;
4301 st->print_cr("Java Threads: ( => current thread )");
4302 ALL_JAVA_THREADS(thread) {
4303 bool is_current = (current == thread);
4304 found_current = found_current || is_current;
4305
4306 st->print("%s", is_current ? "=>" : " ");
4307
4308 st->print(PTR_FORMAT, thread);
4309 st->print(" ");
4310 thread->print_on_error(st, buf, buflen);
4311 st->cr();
4312 }
4313 st->cr();
4314
4315 st->print_cr("Other Threads:");
4316 if (VMThread::vm_thread()) {
4317 bool is_current = (current == VMThread::vm_thread());
4318 found_current = found_current || is_current;
4319 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4320
4321 st->print(PTR_FORMAT, VMThread::vm_thread());
4322 st->print(" ");
4323 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4324 st->cr();
4325 }
4326 WatcherThread* wt = WatcherThread::watcher_thread();
4327 if (wt != NULL) {
4328 bool is_current = (current == wt);
4329 found_current = found_current || is_current;
4330 st->print("%s", is_current ? "=>" : " ");
4331
4332 st->print(PTR_FORMAT, wt);
4333 st->print(" ");
4334 wt->print_on_error(st, buf, buflen);
4335 st->cr();
4336 }
4337 if (!found_current) {
4338 st->cr();
4339 st->print("=>" PTR_FORMAT " (exited) ", current);
4340 current->print_on_error(st, buf, buflen);
4341 st->cr();
4342 }
4343 }
4344
4345 // Internal SpinLock and Mutex
4346 // Based on ParkEvent
4347
4348 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4349 //
4350 // We employ SpinLocks _only for low-contention, fixed-length
4351 // short-duration critical sections where we're concerned
4352 // about native mutex_t or HotSpot Mutex:: latency.
4353 // The mux construct provides a spin-then-block mutual exclusion
4354 // mechanism.
4355 //
4356 // Testing has shown that contention on the ListLock guarding gFreeList
4357 // is common. If we implement ListLock as a simple SpinLock it's common
4358 // for the JVM to devolve to yielding with little progress. This is true
4359 // despite the fact that the critical sections protected by ListLock are
4360 // extremely short.
4361 //
4362 // TODO-FIXME: ListLock should be of type SpinLock.
4363 // We should make this a 1st-class type, integrated into the lock
4364 // hierarchy as leaf-locks. Critically, the SpinLock structure
4365 // should have sufficient padding to avoid false-sharing and excessive
4366 // cache-coherency traffic.
4367
4368
4369 typedef volatile int SpinLockT;
4370
4371 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
4372 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4373 return; // normal fast-path return
4374 }
4375
4376 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4377 TEVENT(SpinAcquire - ctx);
4378 int ctr = 0;
4379 int Yields = 0;
4380 for (;;) {
4381 while (*adr != 0) {
4382 ++ctr;
4383 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4384 if (Yields > 5) {
4385 os::naked_short_sleep(1);
4386 } else {
4387 os::naked_yield();
4388 ++Yields;
4389 }
4390 } else {
4391 SpinPause();
4392 }
4393 }
4394 if (Atomic::cmpxchg(1, adr, 0) == 0) return;
4395 }
4396 }
4397
4398 void Thread::SpinRelease(volatile int * adr) {
4399 assert(*adr != 0, "invariant");
4400 OrderAccess::fence(); // guarantee at least release consistency.
4401 // Roach-motel semantics.
4402 // It's safe if subsequent LDs and STs float "up" into the critical section,
4403 // but prior LDs and STs within the critical section can't be allowed
4404 // to reorder or float past the ST that releases the lock.
4405 // Loads and stores in the critical section - which appear in program
4406 // order before the store that releases the lock - must also appear
4407 // before the store that releases the lock in memory visibility order.
4408 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
4409 // the ST of 0 into the lock-word which releases the lock, so fence
4410 // more than covers this on all platforms.
4411 *adr = 0;
4412 }
4413
4414 // muxAcquire and muxRelease:
4415 //
4416 // * muxAcquire and muxRelease support a single-word lock-word construct.
4417 // The LSB of the word is set IFF the lock is held.
4418 // The remainder of the word points to the head of a singly-linked list
4419 // of threads blocked on the lock.
4420 //
4421 // * The current implementation of muxAcquire-muxRelease uses its own
4422 // dedicated Thread._MuxEvent instance. If we're interested in
4423 // minimizing the peak number of extant ParkEvent instances then
4424 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4425 // as certain invariants were satisfied. Specifically, care would need
4426 // to be taken with regards to consuming unpark() "permits".
4427 // A safe rule of thumb is that a thread would never call muxAcquire()
4428 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4429 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4430 // consume an unpark() permit intended for monitorenter, for instance.
4431 // One way around this would be to widen the restricted-range semaphore
4432 // implemented in park(). Another alternative would be to provide
4433 // multiple instances of the PlatformEvent() for each thread. One
4434 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4435 //
4436 // * Usage:
4437 // -- Only as leaf locks
4438 // -- for short-term locking only as muxAcquire does not perform
4439 // thread state transitions.
4440 //
4441 // Alternatives:
4442 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4443 // but with parking or spin-then-park instead of pure spinning.
4444 // * Use Taura-Oyama-Yonenzawa locks.
4445 // * It's possible to construct a 1-0 lock if we encode the lockword as
4446 // (List,LockByte). Acquire will CAS the full lockword while Release
4447 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4448 // acquiring threads use timers (ParkTimed) to detect and recover from
4449 // the stranding window. Thread/Node structures must be aligned on 256-byte
4450 // boundaries by using placement-new.
4451 // * Augment MCS with advisory back-link fields maintained with CAS().
4452 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4453 // The validity of the backlinks must be ratified before we trust the value.
4454 // If the backlinks are invalid the exiting thread must back-track through the
4455 // the forward links, which are always trustworthy.
4456 // * Add a successor indication. The LockWord is currently encoded as
4457 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4458 // to provide the usual futile-wakeup optimization.
4459 // See RTStt for details.
4460 // * Consider schedctl.sc_nopreempt to cover the critical section.
4461 //
4462
4463
4464 typedef volatile intptr_t MutexT; // Mux Lock-word
4465 enum MuxBits { LOCKBIT = 1 };
4466
4467 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
4468 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4469 if (w == 0) return;
4470 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4471 return;
4472 }
4473
4474 TEVENT(muxAcquire - Contention);
4475 ParkEvent * const Self = Thread::current()->_MuxEvent;
4476 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
4477 for (;;) {
4478 int its = (os::is_MP() ? 100 : 0) + 1;
4479
4480 // Optional spin phase: spin-then-park strategy
4481 while (--its >= 0) {
4482 w = *Lock;
4483 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4484 return;
4485 }
4486 }
4487
4488 Self->reset();
4489 Self->OnList = intptr_t(Lock);
4490 // The following fence() isn't _strictly necessary as the subsequent
4491 // CAS() both serializes execution and ratifies the fetched *Lock value.
4492 OrderAccess::fence();
4493 for (;;) {
4494 w = *Lock;
4495 if ((w & LOCKBIT) == 0) {
4496 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4497 Self->OnList = 0; // hygiene - allows stronger asserts
4498 return;
4499 }
4500 continue; // Interference -- *Lock changed -- Just retry
4501 }
4502 assert(w & LOCKBIT, "invariant");
4503 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4504 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
4505 }
4506
4507 while (Self->OnList != 0) {
4508 Self->park();
4509 }
4510 }
4511 }
4512
4513 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
4514 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
4515 if (w == 0) return;
4516 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4517 return;
4518 }
4519
4520 TEVENT(muxAcquire - Contention);
4521 ParkEvent * ReleaseAfter = NULL;
4522 if (ev == NULL) {
4523 ev = ReleaseAfter = ParkEvent::Allocate(NULL);
4524 }
4525 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
4526 for (;;) {
4527 guarantee(ev->OnList == 0, "invariant");
4528 int its = (os::is_MP() ? 100 : 0) + 1;
4529
4530 // Optional spin phase: spin-then-park strategy
4531 while (--its >= 0) {
4532 w = *Lock;
4533 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4534 if (ReleaseAfter != NULL) {
4535 ParkEvent::Release(ReleaseAfter);
4536 }
4537 return;
4538 }
4539 }
4540
4541 ev->reset();
4542 ev->OnList = intptr_t(Lock);
4543 // The following fence() isn't _strictly necessary as the subsequent
4544 // CAS() both serializes execution and ratifies the fetched *Lock value.
4545 OrderAccess::fence();
4546 for (;;) {
4547 w = *Lock;
4548 if ((w & LOCKBIT) == 0) {
4549 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4550 ev->OnList = 0;
4551 // We call ::Release while holding the outer lock, thus
4552 // artificially lengthening the critical section.
4553 // Consider deferring the ::Release() until the subsequent unlock(),
4554 // after we've dropped the outer lock.
4555 if (ReleaseAfter != NULL) {
4556 ParkEvent::Release(ReleaseAfter);
4557 }
4558 return;
4559 }
4560 continue; // Interference -- *Lock changed -- Just retry
4561 }
4562 assert(w & LOCKBIT, "invariant");
4563 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
4564 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
4565 }
4566
4567 while (ev->OnList != 0) {
4568 ev->park();
4569 }
4570 }
4571 }
4572
4573 // Release() must extract a successor from the list and then wake that thread.
4574 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4575 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4576 // Release() would :
4577 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4578 // (B) Extract a successor from the private list "in-hand"
4579 // (C) attempt to CAS() the residual back into *Lock over null.
4580 // If there were any newly arrived threads and the CAS() would fail.
4581 // In that case Release() would detach the RATs, re-merge the list in-hand
4582 // with the RATs and repeat as needed. Alternately, Release() might
4583 // detach and extract a successor, but then pass the residual list to the wakee.
4584 // The wakee would be responsible for reattaching and remerging before it
4585 // competed for the lock.
4586 //
4587 // Both "pop" and DMR are immune from ABA corruption -- there can be
4588 // multiple concurrent pushers, but only one popper or detacher.
4589 // This implementation pops from the head of the list. This is unfair,
4590 // but tends to provide excellent throughput as hot threads remain hot.
4591 // (We wake recently run threads first).
4592 //
4593 // All paths through muxRelease() will execute a CAS.
4594 // Release consistency -- We depend on the CAS in muxRelease() to provide full
4595 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
4596 // executed within the critical section are complete and globally visible before the
4597 // store (CAS) to the lock-word that releases the lock becomes globally visible.
4598 void Thread::muxRelease(volatile intptr_t * Lock) {
4599 for (;;) {
4600 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
4601 assert(w & LOCKBIT, "invariant");
4602 if (w == LOCKBIT) return;
4603 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
4604 assert(List != NULL, "invariant");
4605 assert(List->OnList == intptr_t(Lock), "invariant");
4606 ParkEvent * const nxt = List->ListNext;
4607 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
4608
4609 // The following CAS() releases the lock and pops the head element.
4610 // The CAS() also ratifies the previously fetched lock-word value.
4611 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4612 continue;
4613 }
4614 List->OnList = 0;
4615 OrderAccess::fence();
4616 List->unpark();
4617 return;
4618 }
4619 }
4620
4621
4622 void Threads::verify() {
4623 ALL_JAVA_THREADS(p) {
4624 p->verify();
4625 }
4626 VMThread* thread = VMThread::vm_thread();
4627 if (thread != NULL) thread->verify();
4628 }