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rev 7151 : 8043224: -Xcheck:jni improvements to exception checking and excessive local refs
Summary: Warning when not checking exceptions from function that require so, also when local refs expand beyond capacity.
Reviewed-by: dsimms
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--- old/hotspot/src/share/vm/runtime/thread.cpp
+++ new/hotspot/src/share/vm/runtime/thread.cpp
1 1 /*
2 - * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
2 + * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 4 *
5 5 * This code is free software; you can redistribute it and/or modify it
6 6 * under the terms of the GNU General Public License version 2 only, as
7 7 * published by the Free Software Foundation.
8 8 *
9 9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 12 * version 2 for more details (a copy is included in the LICENSE file that
13 13 * accompanied this code).
14 14 *
15 15 * You should have received a copy of the GNU General Public License version
16 16 * 2 along with this work; if not, write to the Free Software Foundation,
17 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 18 *
19 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 20 * or visit www.oracle.com if you need additional information or have any
21 21 * questions.
22 22 *
23 23 */
24 24
25 25 #include "precompiled.hpp"
26 26 #include "classfile/classLoader.hpp"
27 27 #include "classfile/javaClasses.hpp"
28 28 #include "classfile/systemDictionary.hpp"
29 29 #include "classfile/vmSymbols.hpp"
30 30 #include "code/scopeDesc.hpp"
31 31 #include "compiler/compileBroker.hpp"
32 32 #include "interpreter/interpreter.hpp"
33 33 #include "interpreter/linkResolver.hpp"
34 34 #include "interpreter/oopMapCache.hpp"
35 35 #include "jvmtifiles/jvmtiEnv.hpp"
36 36 #include "memory/gcLocker.inline.hpp"
37 37 #include "memory/metaspaceShared.hpp"
38 38 #include "memory/oopFactory.hpp"
39 39 #include "memory/universe.inline.hpp"
40 40 #include "oops/instanceKlass.hpp"
41 41 #include "oops/objArrayOop.hpp"
42 42 #include "oops/oop.inline.hpp"
43 43 #include "oops/symbol.hpp"
44 44 #include "prims/jvm_misc.hpp"
45 45 #include "prims/jvmtiExport.hpp"
46 46 #include "prims/jvmtiThreadState.hpp"
47 47 #include "prims/privilegedStack.hpp"
48 48 #include "runtime/arguments.hpp"
49 49 #include "runtime/biasedLocking.hpp"
50 50 #include "runtime/deoptimization.hpp"
51 51 #include "runtime/fprofiler.hpp"
52 52 #include "runtime/frame.inline.hpp"
53 53 #include "runtime/init.hpp"
54 54 #include "runtime/interfaceSupport.hpp"
55 55 #include "runtime/java.hpp"
56 56 #include "runtime/javaCalls.hpp"
57 57 #include "runtime/jniPeriodicChecker.hpp"
58 58 #include "runtime/memprofiler.hpp"
59 59 #include "runtime/mutexLocker.hpp"
60 60 #include "runtime/objectMonitor.hpp"
61 61 #include "runtime/orderAccess.inline.hpp"
62 62 #include "runtime/osThread.hpp"
63 63 #include "runtime/safepoint.hpp"
64 64 #include "runtime/sharedRuntime.hpp"
65 65 #include "runtime/statSampler.hpp"
66 66 #include "runtime/stubRoutines.hpp"
67 67 #include "runtime/task.hpp"
68 68 #include "runtime/thread.inline.hpp"
69 69 #include "runtime/threadCritical.hpp"
70 70 #include "runtime/threadLocalStorage.hpp"
71 71 #include "runtime/vframe.hpp"
72 72 #include "runtime/vframeArray.hpp"
73 73 #include "runtime/vframe_hp.hpp"
74 74 #include "runtime/vmThread.hpp"
75 75 #include "runtime/vm_operations.hpp"
76 76 #include "services/attachListener.hpp"
77 77 #include "services/management.hpp"
78 78 #include "services/memTracker.hpp"
79 79 #include "services/threadService.hpp"
80 80 #include "trace/tracing.hpp"
81 81 #include "trace/traceMacros.hpp"
82 82 #include "utilities/defaultStream.hpp"
83 83 #include "utilities/dtrace.hpp"
84 84 #include "utilities/events.hpp"
85 85 #include "utilities/preserveException.hpp"
86 86 #include "utilities/macros.hpp"
87 87 #ifdef TARGET_OS_FAMILY_linux
88 88 # include "os_linux.inline.hpp"
89 89 #endif
90 90 #ifdef TARGET_OS_FAMILY_solaris
91 91 # include "os_solaris.inline.hpp"
92 92 #endif
93 93 #ifdef TARGET_OS_FAMILY_windows
94 94 # include "os_windows.inline.hpp"
95 95 #endif
96 96 #ifdef TARGET_OS_FAMILY_bsd
97 97 # include "os_bsd.inline.hpp"
98 98 #endif
99 99 #if INCLUDE_ALL_GCS
100 100 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
101 101 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
102 102 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
103 103 #endif // INCLUDE_ALL_GCS
104 104 #ifdef COMPILER1
105 105 #include "c1/c1_Compiler.hpp"
106 106 #endif
107 107 #ifdef COMPILER2
108 108 #include "opto/c2compiler.hpp"
109 109 #include "opto/idealGraphPrinter.hpp"
110 110 #endif
111 111 #if INCLUDE_RTM_OPT
112 112 #include "runtime/rtmLocking.hpp"
113 113 #endif
114 114
115 115 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
116 116
117 117 #ifdef DTRACE_ENABLED
118 118
119 119 // Only bother with this argument setup if dtrace is available
120 120
121 121 #ifndef USDT2
122 122 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
123 123 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
124 124 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
125 125 intptr_t, intptr_t, bool);
126 126 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
127 127 intptr_t, intptr_t, bool);
128 128
129 129 #define DTRACE_THREAD_PROBE(probe, javathread) \
130 130 { \
131 131 ResourceMark rm(this); \
132 132 int len = 0; \
133 133 const char* name = (javathread)->get_thread_name(); \
134 134 len = strlen(name); \
135 135 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
136 136 name, len, \
137 137 java_lang_Thread::thread_id((javathread)->threadObj()), \
138 138 (javathread)->osthread()->thread_id(), \
139 139 java_lang_Thread::is_daemon((javathread)->threadObj())); \
140 140 }
141 141
142 142 #else /* USDT2 */
143 143
144 144 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START
145 145 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP
146 146
147 147 #define DTRACE_THREAD_PROBE(probe, javathread) \
148 148 { \
149 149 ResourceMark rm(this); \
150 150 int len = 0; \
151 151 const char* name = (javathread)->get_thread_name(); \
152 152 len = strlen(name); \
153 153 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \
154 154 (char *) name, len, \
155 155 java_lang_Thread::thread_id((javathread)->threadObj()), \
156 156 (uintptr_t) (javathread)->osthread()->thread_id(), \
157 157 java_lang_Thread::is_daemon((javathread)->threadObj())); \
158 158 }
159 159
160 160 #endif /* USDT2 */
161 161
162 162 #else // ndef DTRACE_ENABLED
163 163
164 164 #define DTRACE_THREAD_PROBE(probe, javathread)
165 165
166 166 #endif // ndef DTRACE_ENABLED
167 167
168 168
169 169 // Class hierarchy
170 170 // - Thread
171 171 // - VMThread
172 172 // - WatcherThread
173 173 // - ConcurrentMarkSweepThread
174 174 // - JavaThread
175 175 // - CompilerThread
176 176
177 177 // ======= Thread ========
178 178 // Support for forcing alignment of thread objects for biased locking
179 179 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
180 180 if (UseBiasedLocking) {
181 181 const int alignment = markOopDesc::biased_lock_alignment;
182 182 size_t aligned_size = size + (alignment - sizeof(intptr_t));
183 183 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
184 184 : AllocateHeap(aligned_size, flags, CURRENT_PC,
185 185 AllocFailStrategy::RETURN_NULL);
186 186 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
187 187 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
188 188 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
189 189 "JavaThread alignment code overflowed allocated storage");
190 190 if (TraceBiasedLocking) {
191 191 if (aligned_addr != real_malloc_addr)
192 192 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
193 193 real_malloc_addr, aligned_addr);
194 194 }
195 195 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
196 196 return aligned_addr;
197 197 } else {
198 198 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
199 199 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
200 200 }
201 201 }
202 202
203 203 void Thread::operator delete(void* p) {
204 204 if (UseBiasedLocking) {
205 205 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
206 206 FreeHeap(real_malloc_addr, mtThread);
207 207 } else {
208 208 FreeHeap(p, mtThread);
209 209 }
210 210 }
211 211
212 212
213 213 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
214 214 // JavaThread
215 215
216 216
217 217 Thread::Thread() {
218 218 // stack and get_thread
219 219 set_stack_base(NULL);
220 220 set_stack_size(0);
221 221 set_self_raw_id(0);
222 222 set_lgrp_id(-1);
223 223
224 224 // allocated data structures
225 225 set_osthread(NULL);
226 226 set_resource_area(new (mtThread)ResourceArea());
227 227 DEBUG_ONLY(_current_resource_mark = NULL;)
228 228 set_handle_area(new (mtThread) HandleArea(NULL));
229 229 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
230 230 set_active_handles(NULL);
231 231 set_free_handle_block(NULL);
232 232 set_last_handle_mark(NULL);
233 233
234 234 // This initial value ==> never claimed.
235 235 _oops_do_parity = 0;
236 236
237 237 _metadata_on_stack_buffer = NULL;
238 238
239 239 // the handle mark links itself to last_handle_mark
240 240 new HandleMark(this);
241 241
242 242 // plain initialization
243 243 debug_only(_owned_locks = NULL;)
244 244 debug_only(_allow_allocation_count = 0;)
245 245 NOT_PRODUCT(_allow_safepoint_count = 0;)
246 246 NOT_PRODUCT(_skip_gcalot = false;)
247 247 _jvmti_env_iteration_count = 0;
248 248 set_allocated_bytes(0);
249 249 _vm_operation_started_count = 0;
250 250 _vm_operation_completed_count = 0;
251 251 _current_pending_monitor = NULL;
252 252 _current_pending_monitor_is_from_java = true;
253 253 _current_waiting_monitor = NULL;
254 254 _num_nested_signal = 0;
255 255 omFreeList = NULL ;
256 256 omFreeCount = 0 ;
257 257 omFreeProvision = 32 ;
258 258 omInUseList = NULL ;
259 259 omInUseCount = 0 ;
260 260
261 261 #ifdef ASSERT
262 262 _visited_for_critical_count = false;
263 263 #endif
264 264
265 265 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
266 266 _suspend_flags = 0;
267 267
268 268 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
269 269 _hashStateX = os::random() ;
270 270 _hashStateY = 842502087 ;
271 271 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
272 272 _hashStateW = 273326509 ;
273 273
274 274 _OnTrap = 0 ;
275 275 _schedctl = NULL ;
276 276 _Stalled = 0 ;
277 277 _TypeTag = 0x2BAD ;
278 278
279 279 // Many of the following fields are effectively final - immutable
280 280 // Note that nascent threads can't use the Native Monitor-Mutex
281 281 // construct until the _MutexEvent is initialized ...
282 282 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
283 283 // we might instead use a stack of ParkEvents that we could provision on-demand.
284 284 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
285 285 // and ::Release()
286 286 _ParkEvent = ParkEvent::Allocate (this) ;
287 287 _SleepEvent = ParkEvent::Allocate (this) ;
288 288 _MutexEvent = ParkEvent::Allocate (this) ;
289 289 _MuxEvent = ParkEvent::Allocate (this) ;
290 290
291 291 #ifdef CHECK_UNHANDLED_OOPS
292 292 if (CheckUnhandledOops) {
293 293 _unhandled_oops = new UnhandledOops(this);
294 294 }
295 295 #endif // CHECK_UNHANDLED_OOPS
296 296 #ifdef ASSERT
297 297 if (UseBiasedLocking) {
298 298 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
299 299 assert(this == _real_malloc_address ||
300 300 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
301 301 "bug in forced alignment of thread objects");
302 302 }
303 303 #endif /* ASSERT */
304 304 }
305 305
306 306 void Thread::initialize_thread_local_storage() {
307 307 // Note: Make sure this method only calls
308 308 // non-blocking operations. Otherwise, it might not work
309 309 // with the thread-startup/safepoint interaction.
310 310
311 311 // During Java thread startup, safepoint code should allow this
312 312 // method to complete because it may need to allocate memory to
313 313 // store information for the new thread.
314 314
315 315 // initialize structure dependent on thread local storage
316 316 ThreadLocalStorage::set_thread(this);
317 317 }
318 318
319 319 void Thread::record_stack_base_and_size() {
320 320 set_stack_base(os::current_stack_base());
321 321 set_stack_size(os::current_stack_size());
322 322 if (is_Java_thread()) {
323 323 ((JavaThread*) this)->set_stack_overflow_limit();
324 324 }
325 325 // CR 7190089: on Solaris, primordial thread's stack is adjusted
326 326 // in initialize_thread(). Without the adjustment, stack size is
327 327 // incorrect if stack is set to unlimited (ulimit -s unlimited).
328 328 // So far, only Solaris has real implementation of initialize_thread().
329 329 //
330 330 // set up any platform-specific state.
331 331 os::initialize_thread(this);
332 332
333 333 #if INCLUDE_NMT
334 334 // record thread's native stack, stack grows downward
335 335 address stack_low_addr = stack_base() - stack_size();
336 336 MemTracker::record_thread_stack(stack_low_addr, stack_size());
337 337 #endif // INCLUDE_NMT
338 338 }
339 339
340 340
341 341 Thread::~Thread() {
342 342 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
343 343 ObjectSynchronizer::omFlush (this) ;
344 344
345 345 EVENT_THREAD_DESTRUCT(this);
346 346
347 347 // stack_base can be NULL if the thread is never started or exited before
348 348 // record_stack_base_and_size called. Although, we would like to ensure
349 349 // that all started threads do call record_stack_base_and_size(), there is
350 350 // not proper way to enforce that.
351 351 #if INCLUDE_NMT
352 352 if (_stack_base != NULL) {
353 353 address low_stack_addr = stack_base() - stack_size();
354 354 MemTracker::release_thread_stack(low_stack_addr, stack_size());
355 355 #ifdef ASSERT
356 356 set_stack_base(NULL);
357 357 #endif
358 358 }
359 359 #endif // INCLUDE_NMT
360 360
361 361 // deallocate data structures
362 362 delete resource_area();
363 363 // since the handle marks are using the handle area, we have to deallocated the root
364 364 // handle mark before deallocating the thread's handle area,
365 365 assert(last_handle_mark() != NULL, "check we have an element");
366 366 delete last_handle_mark();
367 367 assert(last_handle_mark() == NULL, "check we have reached the end");
368 368
369 369 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
370 370 // We NULL out the fields for good hygiene.
371 371 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
372 372 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
373 373 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
374 374 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
375 375
376 376 delete handle_area();
377 377 delete metadata_handles();
378 378
379 379 // osthread() can be NULL, if creation of thread failed.
380 380 if (osthread() != NULL) os::free_thread(osthread());
381 381
382 382 delete _SR_lock;
383 383
384 384 // clear thread local storage if the Thread is deleting itself
385 385 if (this == Thread::current()) {
386 386 ThreadLocalStorage::set_thread(NULL);
387 387 } else {
388 388 // In the case where we're not the current thread, invalidate all the
389 389 // caches in case some code tries to get the current thread or the
390 390 // thread that was destroyed, and gets stale information.
391 391 ThreadLocalStorage::invalidate_all();
392 392 }
393 393 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
394 394 }
395 395
396 396 // NOTE: dummy function for assertion purpose.
397 397 void Thread::run() {
398 398 ShouldNotReachHere();
399 399 }
400 400
401 401 #ifdef ASSERT
402 402 // Private method to check for dangling thread pointer
403 403 void check_for_dangling_thread_pointer(Thread *thread) {
404 404 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
405 405 "possibility of dangling Thread pointer");
406 406 }
407 407 #endif
408 408
409 409
410 410 #ifndef PRODUCT
411 411 // Tracing method for basic thread operations
412 412 void Thread::trace(const char* msg, const Thread* const thread) {
413 413 if (!TraceThreadEvents) return;
414 414 ResourceMark rm;
415 415 ThreadCritical tc;
416 416 const char *name = "non-Java thread";
417 417 int prio = -1;
418 418 if (thread->is_Java_thread()
419 419 && !thread->is_Compiler_thread()) {
420 420 // The Threads_lock must be held to get information about
421 421 // this thread but may not be in some situations when
422 422 // tracing thread events.
423 423 bool release_Threads_lock = false;
424 424 if (!Threads_lock->owned_by_self()) {
425 425 Threads_lock->lock();
426 426 release_Threads_lock = true;
427 427 }
428 428 JavaThread* jt = (JavaThread *)thread;
429 429 name = (char *)jt->get_thread_name();
430 430 oop thread_oop = jt->threadObj();
431 431 if (thread_oop != NULL) {
432 432 prio = java_lang_Thread::priority(thread_oop);
433 433 }
434 434 if (release_Threads_lock) {
435 435 Threads_lock->unlock();
436 436 }
437 437 }
438 438 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
439 439 }
440 440 #endif
441 441
442 442
443 443 ThreadPriority Thread::get_priority(const Thread* const thread) {
444 444 trace("get priority", thread);
445 445 ThreadPriority priority;
446 446 // Can return an error!
447 447 (void)os::get_priority(thread, priority);
448 448 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
449 449 return priority;
450 450 }
451 451
452 452 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
453 453 trace("set priority", thread);
454 454 debug_only(check_for_dangling_thread_pointer(thread);)
455 455 // Can return an error!
456 456 (void)os::set_priority(thread, priority);
457 457 }
458 458
459 459
460 460 void Thread::start(Thread* thread) {
461 461 trace("start", thread);
462 462 // Start is different from resume in that its safety is guaranteed by context or
463 463 // being called from a Java method synchronized on the Thread object.
464 464 if (!DisableStartThread) {
465 465 if (thread->is_Java_thread()) {
466 466 // Initialize the thread state to RUNNABLE before starting this thread.
467 467 // Can not set it after the thread started because we do not know the
468 468 // exact thread state at that time. It could be in MONITOR_WAIT or
469 469 // in SLEEPING or some other state.
470 470 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
471 471 java_lang_Thread::RUNNABLE);
472 472 }
473 473 os::start_thread(thread);
474 474 }
475 475 }
476 476
477 477 // Enqueue a VM_Operation to do the job for us - sometime later
478 478 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
479 479 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
480 480 VMThread::execute(vm_stop);
481 481 }
482 482
483 483
484 484 //
485 485 // Check if an external suspend request has completed (or has been
486 486 // cancelled). Returns true if the thread is externally suspended and
487 487 // false otherwise.
488 488 //
489 489 // The bits parameter returns information about the code path through
490 490 // the routine. Useful for debugging:
491 491 //
492 492 // set in is_ext_suspend_completed():
493 493 // 0x00000001 - routine was entered
494 494 // 0x00000010 - routine return false at end
495 495 // 0x00000100 - thread exited (return false)
496 496 // 0x00000200 - suspend request cancelled (return false)
497 497 // 0x00000400 - thread suspended (return true)
498 498 // 0x00001000 - thread is in a suspend equivalent state (return true)
499 499 // 0x00002000 - thread is native and walkable (return true)
500 500 // 0x00004000 - thread is native_trans and walkable (needed retry)
501 501 //
502 502 // set in wait_for_ext_suspend_completion():
503 503 // 0x00010000 - routine was entered
504 504 // 0x00020000 - suspend request cancelled before loop (return false)
505 505 // 0x00040000 - thread suspended before loop (return true)
506 506 // 0x00080000 - suspend request cancelled in loop (return false)
507 507 // 0x00100000 - thread suspended in loop (return true)
508 508 // 0x00200000 - suspend not completed during retry loop (return false)
509 509 //
510 510
511 511 // Helper class for tracing suspend wait debug bits.
512 512 //
513 513 // 0x00000100 indicates that the target thread exited before it could
514 514 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
515 515 // 0x00080000 each indicate a cancelled suspend request so they don't
516 516 // count as wait failures either.
517 517 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
518 518
519 519 class TraceSuspendDebugBits : public StackObj {
520 520 private:
521 521 JavaThread * jt;
522 522 bool is_wait;
523 523 bool called_by_wait; // meaningful when !is_wait
524 524 uint32_t * bits;
525 525
526 526 public:
527 527 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
528 528 uint32_t *_bits) {
529 529 jt = _jt;
530 530 is_wait = _is_wait;
531 531 called_by_wait = _called_by_wait;
532 532 bits = _bits;
533 533 }
534 534
535 535 ~TraceSuspendDebugBits() {
536 536 if (!is_wait) {
537 537 #if 1
538 538 // By default, don't trace bits for is_ext_suspend_completed() calls.
539 539 // That trace is very chatty.
540 540 return;
541 541 #else
542 542 if (!called_by_wait) {
543 543 // If tracing for is_ext_suspend_completed() is enabled, then only
544 544 // trace calls to it from wait_for_ext_suspend_completion()
545 545 return;
546 546 }
547 547 #endif
548 548 }
549 549
550 550 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
551 551 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
552 552 MutexLocker ml(Threads_lock); // needed for get_thread_name()
553 553 ResourceMark rm;
554 554
555 555 tty->print_cr(
556 556 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
557 557 jt->get_thread_name(), *bits);
558 558
559 559 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
560 560 }
561 561 }
562 562 }
563 563 };
564 564 #undef DEBUG_FALSE_BITS
565 565
566 566
567 567 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
568 568 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
569 569
570 570 bool did_trans_retry = false; // only do thread_in_native_trans retry once
571 571 bool do_trans_retry; // flag to force the retry
572 572
573 573 *bits |= 0x00000001;
574 574
575 575 do {
576 576 do_trans_retry = false;
577 577
578 578 if (is_exiting()) {
579 579 // Thread is in the process of exiting. This is always checked
580 580 // first to reduce the risk of dereferencing a freed JavaThread.
581 581 *bits |= 0x00000100;
582 582 return false;
583 583 }
584 584
585 585 if (!is_external_suspend()) {
586 586 // Suspend request is cancelled. This is always checked before
587 587 // is_ext_suspended() to reduce the risk of a rogue resume
588 588 // confusing the thread that made the suspend request.
589 589 *bits |= 0x00000200;
590 590 return false;
591 591 }
592 592
593 593 if (is_ext_suspended()) {
594 594 // thread is suspended
595 595 *bits |= 0x00000400;
596 596 return true;
597 597 }
598 598
599 599 // Now that we no longer do hard suspends of threads running
600 600 // native code, the target thread can be changing thread state
601 601 // while we are in this routine:
602 602 //
603 603 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
604 604 //
605 605 // We save a copy of the thread state as observed at this moment
606 606 // and make our decision about suspend completeness based on the
607 607 // copy. This closes the race where the thread state is seen as
608 608 // _thread_in_native_trans in the if-thread_blocked check, but is
609 609 // seen as _thread_blocked in if-thread_in_native_trans check.
610 610 JavaThreadState save_state = thread_state();
611 611
612 612 if (save_state == _thread_blocked && is_suspend_equivalent()) {
613 613 // If the thread's state is _thread_blocked and this blocking
614 614 // condition is known to be equivalent to a suspend, then we can
615 615 // consider the thread to be externally suspended. This means that
616 616 // the code that sets _thread_blocked has been modified to do
617 617 // self-suspension if the blocking condition releases. We also
618 618 // used to check for CONDVAR_WAIT here, but that is now covered by
619 619 // the _thread_blocked with self-suspension check.
620 620 //
621 621 // Return true since we wouldn't be here unless there was still an
622 622 // external suspend request.
623 623 *bits |= 0x00001000;
624 624 return true;
625 625 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
626 626 // Threads running native code will self-suspend on native==>VM/Java
627 627 // transitions. If its stack is walkable (should always be the case
628 628 // unless this function is called before the actual java_suspend()
629 629 // call), then the wait is done.
630 630 *bits |= 0x00002000;
631 631 return true;
632 632 } else if (!called_by_wait && !did_trans_retry &&
633 633 save_state == _thread_in_native_trans &&
634 634 frame_anchor()->walkable()) {
635 635 // The thread is transitioning from thread_in_native to another
636 636 // thread state. check_safepoint_and_suspend_for_native_trans()
637 637 // will force the thread to self-suspend. If it hasn't gotten
638 638 // there yet we may have caught the thread in-between the native
639 639 // code check above and the self-suspend. Lucky us. If we were
640 640 // called by wait_for_ext_suspend_completion(), then it
641 641 // will be doing the retries so we don't have to.
642 642 //
643 643 // Since we use the saved thread state in the if-statement above,
644 644 // there is a chance that the thread has already transitioned to
645 645 // _thread_blocked by the time we get here. In that case, we will
646 646 // make a single unnecessary pass through the logic below. This
647 647 // doesn't hurt anything since we still do the trans retry.
648 648
649 649 *bits |= 0x00004000;
650 650
651 651 // Once the thread leaves thread_in_native_trans for another
652 652 // thread state, we break out of this retry loop. We shouldn't
653 653 // need this flag to prevent us from getting back here, but
654 654 // sometimes paranoia is good.
655 655 did_trans_retry = true;
656 656
657 657 // We wait for the thread to transition to a more usable state.
658 658 for (int i = 1; i <= SuspendRetryCount; i++) {
659 659 // We used to do an "os::yield_all(i)" call here with the intention
660 660 // that yielding would increase on each retry. However, the parameter
661 661 // is ignored on Linux which means the yield didn't scale up. Waiting
662 662 // on the SR_lock below provides a much more predictable scale up for
663 663 // the delay. It also provides a simple/direct point to check for any
664 664 // safepoint requests from the VMThread
665 665
666 666 // temporarily drops SR_lock while doing wait with safepoint check
667 667 // (if we're a JavaThread - the WatcherThread can also call this)
668 668 // and increase delay with each retry
669 669 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
670 670
671 671 // check the actual thread state instead of what we saved above
672 672 if (thread_state() != _thread_in_native_trans) {
673 673 // the thread has transitioned to another thread state so
674 674 // try all the checks (except this one) one more time.
675 675 do_trans_retry = true;
676 676 break;
677 677 }
678 678 } // end retry loop
679 679
680 680
681 681 }
682 682 } while (do_trans_retry);
683 683
684 684 *bits |= 0x00000010;
685 685 return false;
686 686 }
687 687
688 688 //
689 689 // Wait for an external suspend request to complete (or be cancelled).
690 690 // Returns true if the thread is externally suspended and false otherwise.
691 691 //
692 692 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
693 693 uint32_t *bits) {
694 694 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
695 695 false /* !called_by_wait */, bits);
696 696
697 697 // local flag copies to minimize SR_lock hold time
698 698 bool is_suspended;
699 699 bool pending;
700 700 uint32_t reset_bits;
701 701
702 702 // set a marker so is_ext_suspend_completed() knows we are the caller
703 703 *bits |= 0x00010000;
704 704
705 705 // We use reset_bits to reinitialize the bits value at the top of
706 706 // each retry loop. This allows the caller to make use of any
707 707 // unused bits for their own marking purposes.
708 708 reset_bits = *bits;
709 709
710 710 {
711 711 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
712 712 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
713 713 delay, bits);
714 714 pending = is_external_suspend();
715 715 }
716 716 // must release SR_lock to allow suspension to complete
717 717
718 718 if (!pending) {
719 719 // A cancelled suspend request is the only false return from
720 720 // is_ext_suspend_completed() that keeps us from entering the
721 721 // retry loop.
722 722 *bits |= 0x00020000;
723 723 return false;
724 724 }
725 725
726 726 if (is_suspended) {
727 727 *bits |= 0x00040000;
728 728 return true;
729 729 }
730 730
731 731 for (int i = 1; i <= retries; i++) {
732 732 *bits = reset_bits; // reinit to only track last retry
733 733
734 734 // We used to do an "os::yield_all(i)" call here with the intention
735 735 // that yielding would increase on each retry. However, the parameter
736 736 // is ignored on Linux which means the yield didn't scale up. Waiting
737 737 // on the SR_lock below provides a much more predictable scale up for
738 738 // the delay. It also provides a simple/direct point to check for any
739 739 // safepoint requests from the VMThread
740 740
741 741 {
742 742 MutexLocker ml(SR_lock());
743 743 // wait with safepoint check (if we're a JavaThread - the WatcherThread
744 744 // can also call this) and increase delay with each retry
745 745 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
746 746
747 747 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
748 748 delay, bits);
749 749
750 750 // It is possible for the external suspend request to be cancelled
751 751 // (by a resume) before the actual suspend operation is completed.
752 752 // Refresh our local copy to see if we still need to wait.
753 753 pending = is_external_suspend();
754 754 }
755 755
756 756 if (!pending) {
757 757 // A cancelled suspend request is the only false return from
758 758 // is_ext_suspend_completed() that keeps us from staying in the
759 759 // retry loop.
760 760 *bits |= 0x00080000;
761 761 return false;
762 762 }
763 763
764 764 if (is_suspended) {
765 765 *bits |= 0x00100000;
766 766 return true;
767 767 }
768 768 } // end retry loop
769 769
770 770 // thread did not suspend after all our retries
771 771 *bits |= 0x00200000;
772 772 return false;
773 773 }
774 774
775 775 #ifndef PRODUCT
776 776 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
777 777
778 778 // This should not need to be atomic as the only way for simultaneous
779 779 // updates is via interrupts. Even then this should be rare or non-existant
780 780 // and we don't care that much anyway.
781 781
782 782 int index = _jmp_ring_index;
783 783 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
784 784 _jmp_ring[index]._target = (intptr_t) target;
785 785 _jmp_ring[index]._instruction = (intptr_t) instr;
786 786 _jmp_ring[index]._file = file;
787 787 _jmp_ring[index]._line = line;
788 788 }
789 789 #endif /* PRODUCT */
790 790
791 791 // Called by flat profiler
792 792 // Callers have already called wait_for_ext_suspend_completion
793 793 // The assertion for that is currently too complex to put here:
794 794 bool JavaThread::profile_last_Java_frame(frame* _fr) {
795 795 bool gotframe = false;
796 796 // self suspension saves needed state.
797 797 if (has_last_Java_frame() && _anchor.walkable()) {
798 798 *_fr = pd_last_frame();
799 799 gotframe = true;
800 800 }
801 801 return gotframe;
802 802 }
803 803
804 804 void Thread::interrupt(Thread* thread) {
805 805 trace("interrupt", thread);
806 806 debug_only(check_for_dangling_thread_pointer(thread);)
807 807 os::interrupt(thread);
808 808 }
809 809
810 810 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
811 811 trace("is_interrupted", thread);
812 812 debug_only(check_for_dangling_thread_pointer(thread);)
813 813 // Note: If clear_interrupted==false, this simply fetches and
814 814 // returns the value of the field osthread()->interrupted().
815 815 return os::is_interrupted(thread, clear_interrupted);
816 816 }
817 817
818 818
819 819 // GC Support
820 820 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
821 821 jint thread_parity = _oops_do_parity;
822 822 if (thread_parity != strong_roots_parity) {
823 823 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
824 824 if (res == thread_parity) {
825 825 return true;
826 826 } else {
827 827 guarantee(res == strong_roots_parity, "Or else what?");
828 828 assert(SharedHeap::heap()->workers()->active_workers() > 0,
829 829 "Should only fail when parallel.");
830 830 return false;
831 831 }
832 832 }
833 833 assert(SharedHeap::heap()->workers()->active_workers() > 0,
834 834 "Should only fail when parallel.");
835 835 return false;
836 836 }
837 837
838 838 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
839 839 active_handles()->oops_do(f);
840 840 // Do oop for ThreadShadow
841 841 f->do_oop((oop*)&_pending_exception);
842 842 handle_area()->oops_do(f);
843 843 }
844 844
845 845 void Thread::nmethods_do(CodeBlobClosure* cf) {
846 846 // no nmethods in a generic thread...
847 847 }
848 848
849 849 void Thread::metadata_do(void f(Metadata*)) {
850 850 if (metadata_handles() != NULL) {
851 851 for (int i = 0; i< metadata_handles()->length(); i++) {
852 852 f(metadata_handles()->at(i));
853 853 }
854 854 }
855 855 }
856 856
857 857 void Thread::print_on(outputStream* st) const {
858 858 // get_priority assumes osthread initialized
859 859 if (osthread() != NULL) {
860 860 int os_prio;
861 861 if (os::get_native_priority(this, &os_prio) == OS_OK) {
862 862 st->print("os_prio=%d ", os_prio);
863 863 }
864 864 st->print("tid=" INTPTR_FORMAT " ", this);
865 865 ext().print_on(st);
866 866 osthread()->print_on(st);
867 867 }
868 868 debug_only(if (WizardMode) print_owned_locks_on(st);)
869 869 }
870 870
871 871 // Thread::print_on_error() is called by fatal error handler. Don't use
872 872 // any lock or allocate memory.
873 873 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
874 874 if (is_VM_thread()) st->print("VMThread");
875 875 else if (is_Compiler_thread()) st->print("CompilerThread");
876 876 else if (is_Java_thread()) st->print("JavaThread");
877 877 else if (is_GC_task_thread()) st->print("GCTaskThread");
878 878 else if (is_Watcher_thread()) st->print("WatcherThread");
879 879 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
880 880 else st->print("Thread");
881 881
882 882 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
883 883 _stack_base - _stack_size, _stack_base);
884 884
885 885 if (osthread()) {
886 886 st->print(" [id=%d]", osthread()->thread_id());
887 887 }
888 888 }
889 889
890 890 #ifdef ASSERT
891 891 void Thread::print_owned_locks_on(outputStream* st) const {
892 892 Monitor *cur = _owned_locks;
893 893 if (cur == NULL) {
894 894 st->print(" (no locks) ");
895 895 } else {
896 896 st->print_cr(" Locks owned:");
897 897 while(cur) {
898 898 cur->print_on(st);
899 899 cur = cur->next();
900 900 }
901 901 }
902 902 }
903 903
904 904 static int ref_use_count = 0;
905 905
906 906 bool Thread::owns_locks_but_compiled_lock() const {
907 907 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
908 908 if (cur != Compile_lock) return true;
909 909 }
910 910 return false;
911 911 }
912 912
913 913
914 914 #endif
915 915
916 916 #ifndef PRODUCT
917 917
918 918 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
919 919 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
920 920 // no threads which allow_vm_block's are held
921 921 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
922 922 // Check if current thread is allowed to block at a safepoint
923 923 if (!(_allow_safepoint_count == 0))
924 924 fatal("Possible safepoint reached by thread that does not allow it");
925 925 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
926 926 fatal("LEAF method calling lock?");
927 927 }
928 928
929 929 #ifdef ASSERT
930 930 if (potential_vm_operation && is_Java_thread()
931 931 && !Universe::is_bootstrapping()) {
932 932 // Make sure we do not hold any locks that the VM thread also uses.
933 933 // This could potentially lead to deadlocks
934 934 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
935 935 // Threads_lock is special, since the safepoint synchronization will not start before this is
936 936 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
937 937 // since it is used to transfer control between JavaThreads and the VMThread
938 938 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
939 939 if ( (cur->allow_vm_block() &&
940 940 cur != Threads_lock &&
941 941 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
942 942 cur != VMOperationRequest_lock &&
943 943 cur != VMOperationQueue_lock) ||
944 944 cur->rank() == Mutex::special) {
945 945 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
946 946 }
947 947 }
948 948 }
949 949
950 950 if (GCALotAtAllSafepoints) {
951 951 // We could enter a safepoint here and thus have a gc
952 952 InterfaceSupport::check_gc_alot();
953 953 }
954 954 #endif
955 955 }
956 956 #endif
957 957
958 958 bool Thread::is_in_stack(address adr) const {
959 959 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
960 960 address end = os::current_stack_pointer();
961 961 // Allow non Java threads to call this without stack_base
962 962 if (_stack_base == NULL) return true;
963 963 if (stack_base() >= adr && adr >= end) return true;
964 964
965 965 return false;
966 966 }
967 967
968 968
969 969 bool Thread::is_in_usable_stack(address adr) const {
970 970 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
971 971 size_t usable_stack_size = _stack_size - stack_guard_size;
972 972
973 973 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
974 974 }
975 975
976 976
977 977 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
978 978 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
979 979 // used for compilation in the future. If that change is made, the need for these methods
980 980 // should be revisited, and they should be removed if possible.
981 981
982 982 bool Thread::is_lock_owned(address adr) const {
983 983 return on_local_stack(adr);
984 984 }
985 985
986 986 bool Thread::set_as_starting_thread() {
987 987 // NOTE: this must be called inside the main thread.
988 988 return os::create_main_thread((JavaThread*)this);
989 989 }
990 990
991 991 static void initialize_class(Symbol* class_name, TRAPS) {
992 992 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
993 993 InstanceKlass::cast(klass)->initialize(CHECK);
994 994 }
995 995
996 996
997 997 // Creates the initial ThreadGroup
998 998 static Handle create_initial_thread_group(TRAPS) {
999 999 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
1000 1000 instanceKlassHandle klass (THREAD, k);
1001 1001
1002 1002 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
1003 1003 {
1004 1004 JavaValue result(T_VOID);
1005 1005 JavaCalls::call_special(&result,
1006 1006 system_instance,
1007 1007 klass,
1008 1008 vmSymbols::object_initializer_name(),
1009 1009 vmSymbols::void_method_signature(),
1010 1010 CHECK_NH);
1011 1011 }
1012 1012 Universe::set_system_thread_group(system_instance());
1013 1013
1014 1014 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1015 1015 {
1016 1016 JavaValue result(T_VOID);
1017 1017 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1018 1018 JavaCalls::call_special(&result,
1019 1019 main_instance,
1020 1020 klass,
1021 1021 vmSymbols::object_initializer_name(),
1022 1022 vmSymbols::threadgroup_string_void_signature(),
1023 1023 system_instance,
1024 1024 string,
1025 1025 CHECK_NH);
1026 1026 }
1027 1027 return main_instance;
1028 1028 }
1029 1029
1030 1030 // Creates the initial Thread
1031 1031 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1032 1032 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1033 1033 instanceKlassHandle klass (THREAD, k);
1034 1034 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1035 1035
1036 1036 java_lang_Thread::set_thread(thread_oop(), thread);
1037 1037 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1038 1038 thread->set_threadObj(thread_oop());
1039 1039
1040 1040 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1041 1041
1042 1042 JavaValue result(T_VOID);
1043 1043 JavaCalls::call_special(&result, thread_oop,
1044 1044 klass,
1045 1045 vmSymbols::object_initializer_name(),
1046 1046 vmSymbols::threadgroup_string_void_signature(),
1047 1047 thread_group,
1048 1048 string,
1049 1049 CHECK_NULL);
1050 1050 return thread_oop();
1051 1051 }
1052 1052
1053 1053 static void call_initializeSystemClass(TRAPS) {
1054 1054 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1055 1055 instanceKlassHandle klass (THREAD, k);
1056 1056
1057 1057 JavaValue result(T_VOID);
1058 1058 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1059 1059 vmSymbols::void_method_signature(), CHECK);
1060 1060 }
1061 1061
1062 1062 char java_runtime_name[128] = "";
1063 1063 char java_runtime_version[128] = "";
1064 1064
1065 1065 // extract the JRE name from sun.misc.Version.java_runtime_name
1066 1066 static const char* get_java_runtime_name(TRAPS) {
1067 1067 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1068 1068 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1069 1069 fieldDescriptor fd;
1070 1070 bool found = k != NULL &&
1071 1071 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1072 1072 vmSymbols::string_signature(), &fd);
1073 1073 if (found) {
1074 1074 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1075 1075 if (name_oop == NULL)
1076 1076 return NULL;
1077 1077 const char* name = java_lang_String::as_utf8_string(name_oop,
1078 1078 java_runtime_name,
1079 1079 sizeof(java_runtime_name));
1080 1080 return name;
1081 1081 } else {
1082 1082 return NULL;
1083 1083 }
1084 1084 }
1085 1085
1086 1086 // extract the JRE version from sun.misc.Version.java_runtime_version
1087 1087 static const char* get_java_runtime_version(TRAPS) {
1088 1088 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1089 1089 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1090 1090 fieldDescriptor fd;
1091 1091 bool found = k != NULL &&
1092 1092 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1093 1093 vmSymbols::string_signature(), &fd);
1094 1094 if (found) {
1095 1095 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1096 1096 if (name_oop == NULL)
1097 1097 return NULL;
1098 1098 const char* name = java_lang_String::as_utf8_string(name_oop,
1099 1099 java_runtime_version,
1100 1100 sizeof(java_runtime_version));
1101 1101 return name;
1102 1102 } else {
1103 1103 return NULL;
1104 1104 }
1105 1105 }
1106 1106
1107 1107 // General purpose hook into Java code, run once when the VM is initialized.
1108 1108 // The Java library method itself may be changed independently from the VM.
1109 1109 static void call_postVMInitHook(TRAPS) {
1110 1110 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1111 1111 instanceKlassHandle klass (THREAD, k);
1112 1112 if (klass.not_null()) {
1113 1113 JavaValue result(T_VOID);
1114 1114 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1115 1115 vmSymbols::void_method_signature(),
1116 1116 CHECK);
1117 1117 }
1118 1118 }
1119 1119
1120 1120 static void reset_vm_info_property(TRAPS) {
1121 1121 // the vm info string
1122 1122 ResourceMark rm(THREAD);
1123 1123 const char *vm_info = VM_Version::vm_info_string();
1124 1124
1125 1125 // java.lang.System class
1126 1126 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1127 1127 instanceKlassHandle klass (THREAD, k);
1128 1128
1129 1129 // setProperty arguments
1130 1130 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1131 1131 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1132 1132
1133 1133 // return value
1134 1134 JavaValue r(T_OBJECT);
1135 1135
1136 1136 // public static String setProperty(String key, String value);
1137 1137 JavaCalls::call_static(&r,
1138 1138 klass,
1139 1139 vmSymbols::setProperty_name(),
1140 1140 vmSymbols::string_string_string_signature(),
1141 1141 key_str,
1142 1142 value_str,
1143 1143 CHECK);
1144 1144 }
1145 1145
1146 1146
1147 1147 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1148 1148 assert(thread_group.not_null(), "thread group should be specified");
1149 1149 assert(threadObj() == NULL, "should only create Java thread object once");
1150 1150
1151 1151 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1152 1152 instanceKlassHandle klass (THREAD, k);
1153 1153 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1154 1154
1155 1155 java_lang_Thread::set_thread(thread_oop(), this);
1156 1156 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1157 1157 set_threadObj(thread_oop());
1158 1158
1159 1159 JavaValue result(T_VOID);
1160 1160 if (thread_name != NULL) {
1161 1161 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1162 1162 // Thread gets assigned specified name and null target
1163 1163 JavaCalls::call_special(&result,
1164 1164 thread_oop,
1165 1165 klass,
1166 1166 vmSymbols::object_initializer_name(),
1167 1167 vmSymbols::threadgroup_string_void_signature(),
1168 1168 thread_group, // Argument 1
1169 1169 name, // Argument 2
1170 1170 THREAD);
1171 1171 } else {
1172 1172 // Thread gets assigned name "Thread-nnn" and null target
1173 1173 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1174 1174 JavaCalls::call_special(&result,
1175 1175 thread_oop,
1176 1176 klass,
1177 1177 vmSymbols::object_initializer_name(),
1178 1178 vmSymbols::threadgroup_runnable_void_signature(),
1179 1179 thread_group, // Argument 1
1180 1180 Handle(), // Argument 2
1181 1181 THREAD);
1182 1182 }
1183 1183
1184 1184
1185 1185 if (daemon) {
1186 1186 java_lang_Thread::set_daemon(thread_oop());
1187 1187 }
1188 1188
1189 1189 if (HAS_PENDING_EXCEPTION) {
1190 1190 return;
1191 1191 }
1192 1192
1193 1193 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1194 1194 Handle threadObj(this, this->threadObj());
1195 1195
1196 1196 JavaCalls::call_special(&result,
1197 1197 thread_group,
1198 1198 group,
1199 1199 vmSymbols::add_method_name(),
1200 1200 vmSymbols::thread_void_signature(),
1201 1201 threadObj, // Arg 1
1202 1202 THREAD);
1203 1203
1204 1204
1205 1205 }
1206 1206
1207 1207 // NamedThread -- non-JavaThread subclasses with multiple
1208 1208 // uniquely named instances should derive from this.
1209 1209 NamedThread::NamedThread() : Thread() {
1210 1210 _name = NULL;
1211 1211 _processed_thread = NULL;
1212 1212 }
1213 1213
1214 1214 NamedThread::~NamedThread() {
1215 1215 if (_name != NULL) {
1216 1216 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1217 1217 _name = NULL;
1218 1218 }
1219 1219 }
1220 1220
1221 1221 void NamedThread::set_name(const char* format, ...) {
1222 1222 guarantee(_name == NULL, "Only get to set name once.");
1223 1223 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1224 1224 guarantee(_name != NULL, "alloc failure");
1225 1225 va_list ap;
1226 1226 va_start(ap, format);
1227 1227 jio_vsnprintf(_name, max_name_len, format, ap);
1228 1228 va_end(ap);
1229 1229 }
1230 1230
1231 1231 // ======= WatcherThread ========
1232 1232
1233 1233 // The watcher thread exists to simulate timer interrupts. It should
1234 1234 // be replaced by an abstraction over whatever native support for
1235 1235 // timer interrupts exists on the platform.
1236 1236
1237 1237 WatcherThread* WatcherThread::_watcher_thread = NULL;
1238 1238 bool WatcherThread::_startable = false;
1239 1239 volatile bool WatcherThread::_should_terminate = false;
1240 1240
1241 1241 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1242 1242 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1243 1243 if (os::create_thread(this, os::watcher_thread)) {
1244 1244 _watcher_thread = this;
1245 1245
1246 1246 // Set the watcher thread to the highest OS priority which should not be
1247 1247 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1248 1248 // is created. The only normal thread using this priority is the reference
1249 1249 // handler thread, which runs for very short intervals only.
1250 1250 // If the VMThread's priority is not lower than the WatcherThread profiling
1251 1251 // will be inaccurate.
1252 1252 os::set_priority(this, MaxPriority);
1253 1253 if (!DisableStartThread) {
1254 1254 os::start_thread(this);
1255 1255 }
1256 1256 }
1257 1257 }
1258 1258
1259 1259 int WatcherThread::sleep() const {
1260 1260 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1261 1261
1262 1262 // remaining will be zero if there are no tasks,
1263 1263 // causing the WatcherThread to sleep until a task is
1264 1264 // enrolled
1265 1265 int remaining = PeriodicTask::time_to_wait();
1266 1266 int time_slept = 0;
1267 1267
1268 1268 // we expect this to timeout - we only ever get unparked when
1269 1269 // we should terminate or when a new task has been enrolled
1270 1270 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1271 1271
1272 1272 jlong time_before_loop = os::javaTimeNanos();
1273 1273
1274 1274 for (;;) {
1275 1275 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1276 1276 jlong now = os::javaTimeNanos();
1277 1277
1278 1278 if (remaining == 0) {
1279 1279 // if we didn't have any tasks we could have waited for a long time
1280 1280 // consider the time_slept zero and reset time_before_loop
1281 1281 time_slept = 0;
1282 1282 time_before_loop = now;
1283 1283 } else {
1284 1284 // need to recalulate since we might have new tasks in _tasks
1285 1285 time_slept = (int) ((now - time_before_loop) / 1000000);
1286 1286 }
1287 1287
1288 1288 // Change to task list or spurious wakeup of some kind
1289 1289 if (timedout || _should_terminate) {
1290 1290 break;
1291 1291 }
1292 1292
1293 1293 remaining = PeriodicTask::time_to_wait();
1294 1294 if (remaining == 0) {
1295 1295 // Last task was just disenrolled so loop around and wait until
1296 1296 // another task gets enrolled
1297 1297 continue;
1298 1298 }
1299 1299
1300 1300 remaining -= time_slept;
1301 1301 if (remaining <= 0)
1302 1302 break;
1303 1303 }
1304 1304
1305 1305 return time_slept;
1306 1306 }
1307 1307
1308 1308 void WatcherThread::run() {
1309 1309 assert(this == watcher_thread(), "just checking");
1310 1310
1311 1311 this->record_stack_base_and_size();
1312 1312 this->initialize_thread_local_storage();
1313 1313 this->set_active_handles(JNIHandleBlock::allocate_block());
1314 1314 while(!_should_terminate) {
1315 1315 assert(watcher_thread() == Thread::current(), "thread consistency check");
1316 1316 assert(watcher_thread() == this, "thread consistency check");
1317 1317
1318 1318 // Calculate how long it'll be until the next PeriodicTask work
1319 1319 // should be done, and sleep that amount of time.
1320 1320 int time_waited = sleep();
1321 1321
1322 1322 if (is_error_reported()) {
1323 1323 // A fatal error has happened, the error handler(VMError::report_and_die)
1324 1324 // should abort JVM after creating an error log file. However in some
1325 1325 // rare cases, the error handler itself might deadlock. Here we try to
1326 1326 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1327 1327 //
1328 1328 // This code is in WatcherThread because WatcherThread wakes up
1329 1329 // periodically so the fatal error handler doesn't need to do anything;
1330 1330 // also because the WatcherThread is less likely to crash than other
1331 1331 // threads.
1332 1332
1333 1333 for (;;) {
1334 1334 if (!ShowMessageBoxOnError
1335 1335 && (OnError == NULL || OnError[0] == '\0')
1336 1336 && Arguments::abort_hook() == NULL) {
1337 1337 os::sleep(this, 2 * 60 * 1000, false);
1338 1338 fdStream err(defaultStream::output_fd());
1339 1339 err.print_raw_cr("# [ timer expired, abort... ]");
1340 1340 // skip atexit/vm_exit/vm_abort hooks
1341 1341 os::die();
1342 1342 }
1343 1343
1344 1344 // Wake up 5 seconds later, the fatal handler may reset OnError or
1345 1345 // ShowMessageBoxOnError when it is ready to abort.
1346 1346 os::sleep(this, 5 * 1000, false);
1347 1347 }
1348 1348 }
1349 1349
1350 1350 PeriodicTask::real_time_tick(time_waited);
1351 1351 }
1352 1352
1353 1353 // Signal that it is terminated
1354 1354 {
1355 1355 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1356 1356 _watcher_thread = NULL;
1357 1357 Terminator_lock->notify();
1358 1358 }
1359 1359
1360 1360 // Thread destructor usually does this..
1361 1361 ThreadLocalStorage::set_thread(NULL);
1362 1362 }
1363 1363
1364 1364 void WatcherThread::start() {
1365 1365 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1366 1366
1367 1367 if (watcher_thread() == NULL && _startable) {
1368 1368 _should_terminate = false;
1369 1369 // Create the single instance of WatcherThread
1370 1370 new WatcherThread();
1371 1371 }
1372 1372 }
1373 1373
1374 1374 void WatcherThread::make_startable() {
1375 1375 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1376 1376 _startable = true;
1377 1377 }
1378 1378
1379 1379 void WatcherThread::stop() {
1380 1380 {
1381 1381 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1382 1382 _should_terminate = true;
1383 1383 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1384 1384
1385 1385 WatcherThread* watcher = watcher_thread();
1386 1386 if (watcher != NULL)
1387 1387 watcher->unpark();
1388 1388 }
1389 1389
1390 1390 // it is ok to take late safepoints here, if needed
1391 1391 MutexLocker mu(Terminator_lock);
1392 1392
1393 1393 while(watcher_thread() != NULL) {
1394 1394 // This wait should make safepoint checks, wait without a timeout,
1395 1395 // and wait as a suspend-equivalent condition.
1396 1396 //
1397 1397 // Note: If the FlatProfiler is running, then this thread is waiting
1398 1398 // for the WatcherThread to terminate and the WatcherThread, via the
1399 1399 // FlatProfiler task, is waiting for the external suspend request on
1400 1400 // this thread to complete. wait_for_ext_suspend_completion() will
1401 1401 // eventually timeout, but that takes time. Making this wait a
1402 1402 // suspend-equivalent condition solves that timeout problem.
1403 1403 //
1404 1404 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1405 1405 Mutex::_as_suspend_equivalent_flag);
1406 1406 }
1407 1407 }
1408 1408
1409 1409 void WatcherThread::unpark() {
1410 1410 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1411 1411 PeriodicTask_lock->notify();
1412 1412 }
1413 1413
1414 1414 void WatcherThread::print_on(outputStream* st) const {
1415 1415 st->print("\"%s\" ", name());
1416 1416 Thread::print_on(st);
1417 1417 st->cr();
1418 1418 }
1419 1419
1420 1420 // ======= JavaThread ========
1421 1421
1422 1422 // A JavaThread is a normal Java thread
1423 1423
1424 1424 void JavaThread::initialize() {
1425 1425 // Initialize fields
1426 1426
1427 1427 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1428 1428 set_claimed_par_id(UINT_MAX);
1429 1429
1430 1430 set_saved_exception_pc(NULL);
1431 1431 set_threadObj(NULL);
1432 1432 _anchor.clear();
1433 1433 set_entry_point(NULL);
1434 1434 set_jni_functions(jni_functions());
1435 1435 set_callee_target(NULL);
1436 1436 set_vm_result(NULL);
1437 1437 set_vm_result_2(NULL);
1438 1438 set_vframe_array_head(NULL);
1439 1439 set_vframe_array_last(NULL);
1440 1440 set_deferred_locals(NULL);
1441 1441 set_deopt_mark(NULL);
1442 1442 set_deopt_nmethod(NULL);
1443 1443 clear_must_deopt_id();
1444 1444 set_monitor_chunks(NULL);
1445 1445 set_next(NULL);
1446 1446 set_thread_state(_thread_new);
1447 1447 _terminated = _not_terminated;
1448 1448 _privileged_stack_top = NULL;
1449 1449 _array_for_gc = NULL;
1450 1450 _suspend_equivalent = false;
1451 1451 _in_deopt_handler = 0;
1452 1452 _doing_unsafe_access = false;
1453 1453 _stack_guard_state = stack_guard_unused;
1454 1454 (void)const_cast<oop&>(_exception_oop = NULL);
1455 1455 _exception_pc = 0;
1456 1456 _exception_handler_pc = 0;
1457 1457 _is_method_handle_return = 0;
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1458 1458 _jvmti_thread_state= NULL;
1459 1459 _should_post_on_exceptions_flag = JNI_FALSE;
1460 1460 _jvmti_get_loaded_classes_closure = NULL;
1461 1461 _interp_only_mode = 0;
1462 1462 _special_runtime_exit_condition = _no_async_condition;
1463 1463 _pending_async_exception = NULL;
1464 1464 _thread_stat = NULL;
1465 1465 _thread_stat = new ThreadStatistics();
1466 1466 _blocked_on_compilation = false;
1467 1467 _jni_active_critical = 0;
1468 + _pending_jni_exception_check_fn = NULL;
1468 1469 _do_not_unlock_if_synchronized = false;
1469 1470 _cached_monitor_info = NULL;
1470 1471 _parker = Parker::Allocate(this) ;
1471 1472
1472 1473 #ifndef PRODUCT
1473 1474 _jmp_ring_index = 0;
1474 1475 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1475 1476 record_jump(NULL, NULL, NULL, 0);
1476 1477 }
1477 1478 #endif /* PRODUCT */
1478 1479
1479 1480 set_thread_profiler(NULL);
1480 1481 if (FlatProfiler::is_active()) {
1481 1482 // This is where we would decide to either give each thread it's own profiler
1482 1483 // or use one global one from FlatProfiler,
1483 1484 // or up to some count of the number of profiled threads, etc.
1484 1485 ThreadProfiler* pp = new ThreadProfiler();
1485 1486 pp->engage();
1486 1487 set_thread_profiler(pp);
1487 1488 }
1488 1489
1489 1490 // Setup safepoint state info for this thread
1490 1491 ThreadSafepointState::create(this);
1491 1492
1492 1493 debug_only(_java_call_counter = 0);
1493 1494
1494 1495 // JVMTI PopFrame support
1495 1496 _popframe_condition = popframe_inactive;
1496 1497 _popframe_preserved_args = NULL;
1497 1498 _popframe_preserved_args_size = 0;
1498 1499 _frames_to_pop_failed_realloc = 0;
1499 1500
1500 1501 pd_initialize();
1501 1502 }
1502 1503
1503 1504 #if INCLUDE_ALL_GCS
1504 1505 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1505 1506 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1506 1507 #endif // INCLUDE_ALL_GCS
1507 1508
1508 1509 JavaThread::JavaThread(bool is_attaching_via_jni) :
1509 1510 Thread()
1510 1511 #if INCLUDE_ALL_GCS
1511 1512 , _satb_mark_queue(&_satb_mark_queue_set),
1512 1513 _dirty_card_queue(&_dirty_card_queue_set)
1513 1514 #endif // INCLUDE_ALL_GCS
1514 1515 {
1515 1516 initialize();
1516 1517 if (is_attaching_via_jni) {
1517 1518 _jni_attach_state = _attaching_via_jni;
1518 1519 } else {
1519 1520 _jni_attach_state = _not_attaching_via_jni;
1520 1521 }
1521 1522 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1522 1523 }
1523 1524
1524 1525 bool JavaThread::reguard_stack(address cur_sp) {
1525 1526 if (_stack_guard_state != stack_guard_yellow_disabled) {
1526 1527 return true; // Stack already guarded or guard pages not needed.
1527 1528 }
1528 1529
1529 1530 if (register_stack_overflow()) {
1530 1531 // For those architectures which have separate register and
1531 1532 // memory stacks, we must check the register stack to see if
1532 1533 // it has overflowed.
1533 1534 return false;
1534 1535 }
1535 1536
1536 1537 // Java code never executes within the yellow zone: the latter is only
1537 1538 // there to provoke an exception during stack banging. If java code
1538 1539 // is executing there, either StackShadowPages should be larger, or
1539 1540 // some exception code in c1, c2 or the interpreter isn't unwinding
1540 1541 // when it should.
1541 1542 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1542 1543
1543 1544 enable_stack_yellow_zone();
1544 1545 return true;
1545 1546 }
1546 1547
1547 1548 bool JavaThread::reguard_stack(void) {
1548 1549 return reguard_stack(os::current_stack_pointer());
1549 1550 }
1550 1551
1551 1552
1552 1553 void JavaThread::block_if_vm_exited() {
1553 1554 if (_terminated == _vm_exited) {
1554 1555 // _vm_exited is set at safepoint, and Threads_lock is never released
1555 1556 // we will block here forever
1556 1557 Threads_lock->lock_without_safepoint_check();
1557 1558 ShouldNotReachHere();
1558 1559 }
1559 1560 }
1560 1561
1561 1562
1562 1563 // Remove this ifdef when C1 is ported to the compiler interface.
1563 1564 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1564 1565
1565 1566 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1566 1567 Thread()
1567 1568 #if INCLUDE_ALL_GCS
1568 1569 , _satb_mark_queue(&_satb_mark_queue_set),
1569 1570 _dirty_card_queue(&_dirty_card_queue_set)
1570 1571 #endif // INCLUDE_ALL_GCS
1571 1572 {
1572 1573 if (TraceThreadEvents) {
1573 1574 tty->print_cr("creating thread %p", this);
1574 1575 }
1575 1576 initialize();
1576 1577 _jni_attach_state = _not_attaching_via_jni;
1577 1578 set_entry_point(entry_point);
1578 1579 // Create the native thread itself.
1579 1580 // %note runtime_23
1580 1581 os::ThreadType thr_type = os::java_thread;
1581 1582 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1582 1583 os::java_thread;
1583 1584 os::create_thread(this, thr_type, stack_sz);
1584 1585 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1585 1586 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1586 1587 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1587 1588 // the exception consists of creating the exception object & initializing it, initialization
1588 1589 // will leave the VM via a JavaCall and then all locks must be unlocked).
1589 1590 //
1590 1591 // The thread is still suspended when we reach here. Thread must be explicit started
1591 1592 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1592 1593 // by calling Threads:add. The reason why this is not done here, is because the thread
1593 1594 // object must be fully initialized (take a look at JVM_Start)
1594 1595 }
1595 1596
1596 1597 JavaThread::~JavaThread() {
1597 1598 if (TraceThreadEvents) {
1598 1599 tty->print_cr("terminate thread %p", this);
1599 1600 }
1600 1601
1601 1602 // JSR166 -- return the parker to the free list
1602 1603 Parker::Release(_parker);
1603 1604 _parker = NULL ;
1604 1605
1605 1606 // Free any remaining previous UnrollBlock
1606 1607 vframeArray* old_array = vframe_array_last();
1607 1608
1608 1609 if (old_array != NULL) {
1609 1610 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1610 1611 old_array->set_unroll_block(NULL);
1611 1612 delete old_info;
1612 1613 delete old_array;
1613 1614 }
1614 1615
1615 1616 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1616 1617 if (deferred != NULL) {
1617 1618 // This can only happen if thread is destroyed before deoptimization occurs.
1618 1619 assert(deferred->length() != 0, "empty array!");
1619 1620 do {
1620 1621 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1621 1622 deferred->remove_at(0);
1622 1623 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1623 1624 delete dlv;
1624 1625 } while (deferred->length() != 0);
1625 1626 delete deferred;
1626 1627 }
1627 1628
1628 1629 // All Java related clean up happens in exit
1629 1630 ThreadSafepointState::destroy(this);
1630 1631 if (_thread_profiler != NULL) delete _thread_profiler;
1631 1632 if (_thread_stat != NULL) delete _thread_stat;
1632 1633 }
1633 1634
1634 1635
1635 1636 // The first routine called by a new Java thread
1636 1637 void JavaThread::run() {
1637 1638 // initialize thread-local alloc buffer related fields
1638 1639 this->initialize_tlab();
1639 1640
1640 1641 // used to test validitity of stack trace backs
1641 1642 this->record_base_of_stack_pointer();
1642 1643
1643 1644 // Record real stack base and size.
1644 1645 this->record_stack_base_and_size();
1645 1646
1646 1647 // Initialize thread local storage; set before calling MutexLocker
1647 1648 this->initialize_thread_local_storage();
1648 1649
1649 1650 this->create_stack_guard_pages();
1650 1651
1651 1652 this->cache_global_variables();
1652 1653
1653 1654 // Thread is now sufficient initialized to be handled by the safepoint code as being
1654 1655 // in the VM. Change thread state from _thread_new to _thread_in_vm
1655 1656 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1656 1657
1657 1658 assert(JavaThread::current() == this, "sanity check");
1658 1659 assert(!Thread::current()->owns_locks(), "sanity check");
1659 1660
1660 1661 DTRACE_THREAD_PROBE(start, this);
1661 1662
1662 1663 // This operation might block. We call that after all safepoint checks for a new thread has
1663 1664 // been completed.
1664 1665 this->set_active_handles(JNIHandleBlock::allocate_block());
1665 1666
1666 1667 if (JvmtiExport::should_post_thread_life()) {
1667 1668 JvmtiExport::post_thread_start(this);
1668 1669 }
1669 1670
1670 1671 EventThreadStart event;
1671 1672 if (event.should_commit()) {
1672 1673 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1673 1674 event.commit();
1674 1675 }
1675 1676
1676 1677 // We call another function to do the rest so we are sure that the stack addresses used
1677 1678 // from there will be lower than the stack base just computed
1678 1679 thread_main_inner();
1679 1680
1680 1681 // Note, thread is no longer valid at this point!
1681 1682 }
1682 1683
1683 1684
1684 1685 void JavaThread::thread_main_inner() {
1685 1686 assert(JavaThread::current() == this, "sanity check");
1686 1687 assert(this->threadObj() != NULL, "just checking");
1687 1688
1688 1689 // Execute thread entry point unless this thread has a pending exception
1689 1690 // or has been stopped before starting.
1690 1691 // Note: Due to JVM_StopThread we can have pending exceptions already!
1691 1692 if (!this->has_pending_exception() &&
1692 1693 !java_lang_Thread::is_stillborn(this->threadObj())) {
1693 1694 {
1694 1695 ResourceMark rm(this);
1695 1696 this->set_native_thread_name(this->get_thread_name());
1696 1697 }
1697 1698 HandleMark hm(this);
1698 1699 this->entry_point()(this, this);
1699 1700 }
1700 1701
1701 1702 DTRACE_THREAD_PROBE(stop, this);
1702 1703
1703 1704 this->exit(false);
1704 1705 delete this;
1705 1706 }
1706 1707
1707 1708
1708 1709 static void ensure_join(JavaThread* thread) {
1709 1710 // We do not need to grap the Threads_lock, since we are operating on ourself.
1710 1711 Handle threadObj(thread, thread->threadObj());
1711 1712 assert(threadObj.not_null(), "java thread object must exist");
1712 1713 ObjectLocker lock(threadObj, thread);
1713 1714 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1714 1715 thread->clear_pending_exception();
1715 1716 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1716 1717 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1717 1718 // Clear the native thread instance - this makes isAlive return false and allows the join()
1718 1719 // to complete once we've done the notify_all below
1719 1720 java_lang_Thread::set_thread(threadObj(), NULL);
1720 1721 lock.notify_all(thread);
1721 1722 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1722 1723 thread->clear_pending_exception();
1723 1724 }
1724 1725
1725 1726
1726 1727 // For any new cleanup additions, please check to see if they need to be applied to
1727 1728 // cleanup_failed_attach_current_thread as well.
1728 1729 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1729 1730 assert(this == JavaThread::current(), "thread consistency check");
1730 1731
1731 1732 HandleMark hm(this);
1732 1733 Handle uncaught_exception(this, this->pending_exception());
1733 1734 this->clear_pending_exception();
1734 1735 Handle threadObj(this, this->threadObj());
1735 1736 assert(threadObj.not_null(), "Java thread object should be created");
1736 1737
1737 1738 if (get_thread_profiler() != NULL) {
1738 1739 get_thread_profiler()->disengage();
1739 1740 ResourceMark rm;
1740 1741 get_thread_profiler()->print(get_thread_name());
1741 1742 }
1742 1743
1743 1744
1744 1745 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1745 1746 {
1746 1747 EXCEPTION_MARK;
1747 1748
1748 1749 CLEAR_PENDING_EXCEPTION;
1749 1750 }
1750 1751 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1751 1752 // has to be fixed by a runtime query method
1752 1753 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1753 1754 // JSR-166: change call from from ThreadGroup.uncaughtException to
1754 1755 // java.lang.Thread.dispatchUncaughtException
1755 1756 if (uncaught_exception.not_null()) {
1756 1757 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1757 1758 {
1758 1759 EXCEPTION_MARK;
1759 1760 // Check if the method Thread.dispatchUncaughtException() exists. If so
1760 1761 // call it. Otherwise we have an older library without the JSR-166 changes,
1761 1762 // so call ThreadGroup.uncaughtException()
1762 1763 KlassHandle recvrKlass(THREAD, threadObj->klass());
1763 1764 CallInfo callinfo;
1764 1765 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1765 1766 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1766 1767 vmSymbols::dispatchUncaughtException_name(),
1767 1768 vmSymbols::throwable_void_signature(),
1768 1769 KlassHandle(), false, false, THREAD);
1769 1770 CLEAR_PENDING_EXCEPTION;
1770 1771 methodHandle method = callinfo.selected_method();
1771 1772 if (method.not_null()) {
1772 1773 JavaValue result(T_VOID);
1773 1774 JavaCalls::call_virtual(&result,
1774 1775 threadObj, thread_klass,
1775 1776 vmSymbols::dispatchUncaughtException_name(),
1776 1777 vmSymbols::throwable_void_signature(),
1777 1778 uncaught_exception,
1778 1779 THREAD);
1779 1780 } else {
1780 1781 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1781 1782 JavaValue result(T_VOID);
1782 1783 JavaCalls::call_virtual(&result,
1783 1784 group, thread_group,
1784 1785 vmSymbols::uncaughtException_name(),
1785 1786 vmSymbols::thread_throwable_void_signature(),
1786 1787 threadObj, // Arg 1
1787 1788 uncaught_exception, // Arg 2
1788 1789 THREAD);
1789 1790 }
1790 1791 if (HAS_PENDING_EXCEPTION) {
1791 1792 ResourceMark rm(this);
1792 1793 jio_fprintf(defaultStream::error_stream(),
1793 1794 "\nException: %s thrown from the UncaughtExceptionHandler"
1794 1795 " in thread \"%s\"\n",
1795 1796 pending_exception()->klass()->external_name(),
1796 1797 get_thread_name());
1797 1798 CLEAR_PENDING_EXCEPTION;
1798 1799 }
1799 1800 }
1800 1801 }
1801 1802
1802 1803 // Called before the java thread exit since we want to read info
1803 1804 // from java_lang_Thread object
1804 1805 EventThreadEnd event;
1805 1806 if (event.should_commit()) {
1806 1807 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1807 1808 event.commit();
1808 1809 }
1809 1810
1810 1811 // Call after last event on thread
1811 1812 EVENT_THREAD_EXIT(this);
1812 1813
1813 1814 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1814 1815 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1815 1816 // is deprecated anyhow.
1816 1817 if (!is_Compiler_thread()) {
1817 1818 int count = 3;
1818 1819 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1819 1820 EXCEPTION_MARK;
1820 1821 JavaValue result(T_VOID);
1821 1822 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1822 1823 JavaCalls::call_virtual(&result,
1823 1824 threadObj, thread_klass,
1824 1825 vmSymbols::exit_method_name(),
1825 1826 vmSymbols::void_method_signature(),
1826 1827 THREAD);
1827 1828 CLEAR_PENDING_EXCEPTION;
1828 1829 }
1829 1830 }
1830 1831 // notify JVMTI
1831 1832 if (JvmtiExport::should_post_thread_life()) {
1832 1833 JvmtiExport::post_thread_end(this);
1833 1834 }
1834 1835
1835 1836 // We have notified the agents that we are exiting, before we go on,
1836 1837 // we must check for a pending external suspend request and honor it
1837 1838 // in order to not surprise the thread that made the suspend request.
1838 1839 while (true) {
1839 1840 {
1840 1841 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1841 1842 if (!is_external_suspend()) {
1842 1843 set_terminated(_thread_exiting);
1843 1844 ThreadService::current_thread_exiting(this);
1844 1845 break;
1845 1846 }
1846 1847 // Implied else:
1847 1848 // Things get a little tricky here. We have a pending external
1848 1849 // suspend request, but we are holding the SR_lock so we
1849 1850 // can't just self-suspend. So we temporarily drop the lock
1850 1851 // and then self-suspend.
1851 1852 }
1852 1853
1853 1854 ThreadBlockInVM tbivm(this);
1854 1855 java_suspend_self();
1855 1856
1856 1857 // We're done with this suspend request, but we have to loop around
1857 1858 // and check again. Eventually we will get SR_lock without a pending
1858 1859 // external suspend request and will be able to mark ourselves as
1859 1860 // exiting.
1860 1861 }
1861 1862 // no more external suspends are allowed at this point
1862 1863 } else {
1863 1864 // before_exit() has already posted JVMTI THREAD_END events
1864 1865 }
1865 1866
1866 1867 // Notify waiters on thread object. This has to be done after exit() is called
1867 1868 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1868 1869 // group should have the destroyed bit set before waiters are notified).
1869 1870 ensure_join(this);
1870 1871 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1871 1872
1872 1873 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1873 1874 // held by this thread must be released. A detach operation must only
1874 1875 // get here if there are no Java frames on the stack. Therefore, any
1875 1876 // owned monitors at this point MUST be JNI-acquired monitors which are
1876 1877 // pre-inflated and in the monitor cache.
1877 1878 //
1878 1879 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1879 1880 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1880 1881 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1881 1882 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1882 1883 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1883 1884 }
1884 1885
1885 1886 // These things needs to be done while we are still a Java Thread. Make sure that thread
1886 1887 // is in a consistent state, in case GC happens
1887 1888 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1888 1889
1889 1890 if (active_handles() != NULL) {
1890 1891 JNIHandleBlock* block = active_handles();
1891 1892 set_active_handles(NULL);
1892 1893 JNIHandleBlock::release_block(block);
1893 1894 }
1894 1895
1895 1896 if (free_handle_block() != NULL) {
1896 1897 JNIHandleBlock* block = free_handle_block();
1897 1898 set_free_handle_block(NULL);
1898 1899 JNIHandleBlock::release_block(block);
1899 1900 }
1900 1901
1901 1902 // These have to be removed while this is still a valid thread.
1902 1903 remove_stack_guard_pages();
1903 1904
1904 1905 if (UseTLAB) {
1905 1906 tlab().make_parsable(true); // retire TLAB
1906 1907 }
1907 1908
1908 1909 if (JvmtiEnv::environments_might_exist()) {
1909 1910 JvmtiExport::cleanup_thread(this);
1910 1911 }
1911 1912
1912 1913 // We must flush any deferred card marks before removing a thread from
1913 1914 // the list of active threads.
1914 1915 Universe::heap()->flush_deferred_store_barrier(this);
1915 1916 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1916 1917
1917 1918 #if INCLUDE_ALL_GCS
1918 1919 // We must flush the G1-related buffers before removing a thread
1919 1920 // from the list of active threads. We must do this after any deferred
1920 1921 // card marks have been flushed (above) so that any entries that are
1921 1922 // added to the thread's dirty card queue as a result are not lost.
1922 1923 if (UseG1GC) {
1923 1924 flush_barrier_queues();
1924 1925 }
1925 1926 #endif // INCLUDE_ALL_GCS
1926 1927
1927 1928 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1928 1929 Threads::remove(this);
1929 1930 }
1930 1931
1931 1932 #if INCLUDE_ALL_GCS
1932 1933 // Flush G1-related queues.
1933 1934 void JavaThread::flush_barrier_queues() {
1934 1935 satb_mark_queue().flush();
1935 1936 dirty_card_queue().flush();
1936 1937 }
1937 1938
1938 1939 void JavaThread::initialize_queues() {
1939 1940 assert(!SafepointSynchronize::is_at_safepoint(),
1940 1941 "we should not be at a safepoint");
1941 1942
1942 1943 ObjPtrQueue& satb_queue = satb_mark_queue();
1943 1944 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1944 1945 // The SATB queue should have been constructed with its active
1945 1946 // field set to false.
1946 1947 assert(!satb_queue.is_active(), "SATB queue should not be active");
1947 1948 assert(satb_queue.is_empty(), "SATB queue should be empty");
1948 1949 // If we are creating the thread during a marking cycle, we should
1949 1950 // set the active field of the SATB queue to true.
1950 1951 if (satb_queue_set.is_active()) {
1951 1952 satb_queue.set_active(true);
1952 1953 }
1953 1954
1954 1955 DirtyCardQueue& dirty_queue = dirty_card_queue();
1955 1956 // The dirty card queue should have been constructed with its
1956 1957 // active field set to true.
1957 1958 assert(dirty_queue.is_active(), "dirty card queue should be active");
1958 1959 }
1959 1960 #endif // INCLUDE_ALL_GCS
1960 1961
1961 1962 void JavaThread::cleanup_failed_attach_current_thread() {
1962 1963 if (get_thread_profiler() != NULL) {
1963 1964 get_thread_profiler()->disengage();
1964 1965 ResourceMark rm;
1965 1966 get_thread_profiler()->print(get_thread_name());
1966 1967 }
1967 1968
1968 1969 if (active_handles() != NULL) {
1969 1970 JNIHandleBlock* block = active_handles();
1970 1971 set_active_handles(NULL);
1971 1972 JNIHandleBlock::release_block(block);
1972 1973 }
1973 1974
1974 1975 if (free_handle_block() != NULL) {
1975 1976 JNIHandleBlock* block = free_handle_block();
1976 1977 set_free_handle_block(NULL);
1977 1978 JNIHandleBlock::release_block(block);
1978 1979 }
1979 1980
1980 1981 // These have to be removed while this is still a valid thread.
1981 1982 remove_stack_guard_pages();
1982 1983
1983 1984 if (UseTLAB) {
1984 1985 tlab().make_parsable(true); // retire TLAB, if any
1985 1986 }
1986 1987
1987 1988 #if INCLUDE_ALL_GCS
1988 1989 if (UseG1GC) {
1989 1990 flush_barrier_queues();
1990 1991 }
1991 1992 #endif // INCLUDE_ALL_GCS
1992 1993
1993 1994 Threads::remove(this);
1994 1995 delete this;
1995 1996 }
1996 1997
1997 1998
1998 1999
1999 2000
2000 2001 JavaThread* JavaThread::active() {
2001 2002 Thread* thread = ThreadLocalStorage::thread();
2002 2003 assert(thread != NULL, "just checking");
2003 2004 if (thread->is_Java_thread()) {
2004 2005 return (JavaThread*) thread;
2005 2006 } else {
2006 2007 assert(thread->is_VM_thread(), "this must be a vm thread");
2007 2008 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2008 2009 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2009 2010 assert(ret->is_Java_thread(), "must be a Java thread");
2010 2011 return ret;
2011 2012 }
2012 2013 }
2013 2014
2014 2015 bool JavaThread::is_lock_owned(address adr) const {
2015 2016 if (Thread::is_lock_owned(adr)) return true;
2016 2017
2017 2018 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2018 2019 if (chunk->contains(adr)) return true;
2019 2020 }
2020 2021
2021 2022 return false;
2022 2023 }
2023 2024
2024 2025
2025 2026 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2026 2027 chunk->set_next(monitor_chunks());
2027 2028 set_monitor_chunks(chunk);
2028 2029 }
2029 2030
2030 2031 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2031 2032 guarantee(monitor_chunks() != NULL, "must be non empty");
2032 2033 if (monitor_chunks() == chunk) {
2033 2034 set_monitor_chunks(chunk->next());
2034 2035 } else {
2035 2036 MonitorChunk* prev = monitor_chunks();
2036 2037 while (prev->next() != chunk) prev = prev->next();
2037 2038 prev->set_next(chunk->next());
2038 2039 }
2039 2040 }
2040 2041
2041 2042 // JVM support.
2042 2043
2043 2044 // Note: this function shouldn't block if it's called in
2044 2045 // _thread_in_native_trans state (such as from
2045 2046 // check_special_condition_for_native_trans()).
2046 2047 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2047 2048
2048 2049 if (has_last_Java_frame() && has_async_condition()) {
2049 2050 // If we are at a polling page safepoint (not a poll return)
2050 2051 // then we must defer async exception because live registers
2051 2052 // will be clobbered by the exception path. Poll return is
2052 2053 // ok because the call we a returning from already collides
2053 2054 // with exception handling registers and so there is no issue.
2054 2055 // (The exception handling path kills call result registers but
2055 2056 // this is ok since the exception kills the result anyway).
2056 2057
2057 2058 if (is_at_poll_safepoint()) {
2058 2059 // if the code we are returning to has deoptimized we must defer
2059 2060 // the exception otherwise live registers get clobbered on the
2060 2061 // exception path before deoptimization is able to retrieve them.
2061 2062 //
2062 2063 RegisterMap map(this, false);
2063 2064 frame caller_fr = last_frame().sender(&map);
2064 2065 assert(caller_fr.is_compiled_frame(), "what?");
2065 2066 if (caller_fr.is_deoptimized_frame()) {
2066 2067 if (TraceExceptions) {
2067 2068 ResourceMark rm;
2068 2069 tty->print_cr("deferred async exception at compiled safepoint");
2069 2070 }
2070 2071 return;
2071 2072 }
2072 2073 }
2073 2074 }
2074 2075
2075 2076 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2076 2077 if (condition == _no_async_condition) {
2077 2078 // Conditions have changed since has_special_runtime_exit_condition()
2078 2079 // was called:
2079 2080 // - if we were here only because of an external suspend request,
2080 2081 // then that was taken care of above (or cancelled) so we are done
2081 2082 // - if we were here because of another async request, then it has
2082 2083 // been cleared between the has_special_runtime_exit_condition()
2083 2084 // and now so again we are done
2084 2085 return;
2085 2086 }
2086 2087
2087 2088 // Check for pending async. exception
2088 2089 if (_pending_async_exception != NULL) {
2089 2090 // Only overwrite an already pending exception, if it is not a threadDeath.
2090 2091 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2091 2092
2092 2093 // We cannot call Exceptions::_throw(...) here because we cannot block
2093 2094 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2094 2095
2095 2096 if (TraceExceptions) {
2096 2097 ResourceMark rm;
2097 2098 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2098 2099 if (has_last_Java_frame() ) {
2099 2100 frame f = last_frame();
2100 2101 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2101 2102 }
2102 2103 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2103 2104 }
2104 2105 _pending_async_exception = NULL;
2105 2106 clear_has_async_exception();
2106 2107 }
2107 2108 }
2108 2109
2109 2110 if (check_unsafe_error &&
2110 2111 condition == _async_unsafe_access_error && !has_pending_exception()) {
2111 2112 condition = _no_async_condition; // done
2112 2113 switch (thread_state()) {
2113 2114 case _thread_in_vm:
2114 2115 {
2115 2116 JavaThread* THREAD = this;
2116 2117 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2117 2118 }
2118 2119 case _thread_in_native:
2119 2120 {
2120 2121 ThreadInVMfromNative tiv(this);
2121 2122 JavaThread* THREAD = this;
2122 2123 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2123 2124 }
2124 2125 case _thread_in_Java:
2125 2126 {
2126 2127 ThreadInVMfromJava tiv(this);
2127 2128 JavaThread* THREAD = this;
2128 2129 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2129 2130 }
2130 2131 default:
2131 2132 ShouldNotReachHere();
2132 2133 }
2133 2134 }
2134 2135
2135 2136 assert(condition == _no_async_condition || has_pending_exception() ||
2136 2137 (!check_unsafe_error && condition == _async_unsafe_access_error),
2137 2138 "must have handled the async condition, if no exception");
2138 2139 }
2139 2140
2140 2141 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2141 2142 //
2142 2143 // Check for pending external suspend. Internal suspend requests do
2143 2144 // not use handle_special_runtime_exit_condition().
2144 2145 // If JNIEnv proxies are allowed, don't self-suspend if the target
2145 2146 // thread is not the current thread. In older versions of jdbx, jdbx
2146 2147 // threads could call into the VM with another thread's JNIEnv so we
2147 2148 // can be here operating on behalf of a suspended thread (4432884).
2148 2149 bool do_self_suspend = is_external_suspend_with_lock();
2149 2150 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2150 2151 //
2151 2152 // Because thread is external suspended the safepoint code will count
2152 2153 // thread as at a safepoint. This can be odd because we can be here
2153 2154 // as _thread_in_Java which would normally transition to _thread_blocked
2154 2155 // at a safepoint. We would like to mark the thread as _thread_blocked
2155 2156 // before calling java_suspend_self like all other callers of it but
2156 2157 // we must then observe proper safepoint protocol. (We can't leave
2157 2158 // _thread_blocked with a safepoint in progress). However we can be
2158 2159 // here as _thread_in_native_trans so we can't use a normal transition
2159 2160 // constructor/destructor pair because they assert on that type of
2160 2161 // transition. We could do something like:
2161 2162 //
2162 2163 // JavaThreadState state = thread_state();
2163 2164 // set_thread_state(_thread_in_vm);
2164 2165 // {
2165 2166 // ThreadBlockInVM tbivm(this);
2166 2167 // java_suspend_self()
2167 2168 // }
2168 2169 // set_thread_state(_thread_in_vm_trans);
2169 2170 // if (safepoint) block;
2170 2171 // set_thread_state(state);
2171 2172 //
2172 2173 // but that is pretty messy. Instead we just go with the way the
2173 2174 // code has worked before and note that this is the only path to
2174 2175 // java_suspend_self that doesn't put the thread in _thread_blocked
2175 2176 // mode.
2176 2177
2177 2178 frame_anchor()->make_walkable(this);
2178 2179 java_suspend_self();
2179 2180
2180 2181 // We might be here for reasons in addition to the self-suspend request
2181 2182 // so check for other async requests.
2182 2183 }
2183 2184
2184 2185 if (check_asyncs) {
2185 2186 check_and_handle_async_exceptions();
2186 2187 }
2187 2188 }
2188 2189
2189 2190 void JavaThread::send_thread_stop(oop java_throwable) {
2190 2191 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2191 2192 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2192 2193 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2193 2194
2194 2195 // Do not throw asynchronous exceptions against the compiler thread
2195 2196 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2196 2197 if (is_Compiler_thread()) return;
2197 2198
2198 2199 {
2199 2200 // Actually throw the Throwable against the target Thread - however
2200 2201 // only if there is no thread death exception installed already.
2201 2202 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2202 2203 // If the topmost frame is a runtime stub, then we are calling into
2203 2204 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2204 2205 // must deoptimize the caller before continuing, as the compiled exception handler table
2205 2206 // may not be valid
2206 2207 if (has_last_Java_frame()) {
2207 2208 frame f = last_frame();
2208 2209 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2209 2210 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2210 2211 RegisterMap reg_map(this, UseBiasedLocking);
2211 2212 frame compiled_frame = f.sender(®_map);
2212 2213 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2213 2214 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2214 2215 }
2215 2216 }
2216 2217 }
2217 2218
2218 2219 // Set async. pending exception in thread.
2219 2220 set_pending_async_exception(java_throwable);
2220 2221
2221 2222 if (TraceExceptions) {
2222 2223 ResourceMark rm;
2223 2224 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2224 2225 }
2225 2226 // for AbortVMOnException flag
2226 2227 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2227 2228 }
2228 2229 }
2229 2230
2230 2231
2231 2232 // Interrupt thread so it will wake up from a potential wait()
2232 2233 Thread::interrupt(this);
2233 2234 }
2234 2235
2235 2236 // External suspension mechanism.
2236 2237 //
2237 2238 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2238 2239 // to any VM_locks and it is at a transition
2239 2240 // Self-suspension will happen on the transition out of the vm.
2240 2241 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2241 2242 //
2242 2243 // Guarantees on return:
2243 2244 // + Target thread will not execute any new bytecode (that's why we need to
2244 2245 // force a safepoint)
2245 2246 // + Target thread will not enter any new monitors
2246 2247 //
2247 2248 void JavaThread::java_suspend() {
2248 2249 { MutexLocker mu(Threads_lock);
2249 2250 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2250 2251 return;
2251 2252 }
2252 2253 }
2253 2254
2254 2255 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2255 2256 if (!is_external_suspend()) {
2256 2257 // a racing resume has cancelled us; bail out now
2257 2258 return;
2258 2259 }
2259 2260
2260 2261 // suspend is done
2261 2262 uint32_t debug_bits = 0;
2262 2263 // Warning: is_ext_suspend_completed() may temporarily drop the
2263 2264 // SR_lock to allow the thread to reach a stable thread state if
2264 2265 // it is currently in a transient thread state.
2265 2266 if (is_ext_suspend_completed(false /* !called_by_wait */,
2266 2267 SuspendRetryDelay, &debug_bits) ) {
2267 2268 return;
2268 2269 }
2269 2270 }
2270 2271
2271 2272 VM_ForceSafepoint vm_suspend;
2272 2273 VMThread::execute(&vm_suspend);
2273 2274 }
2274 2275
2275 2276 // Part II of external suspension.
2276 2277 // A JavaThread self suspends when it detects a pending external suspend
2277 2278 // request. This is usually on transitions. It is also done in places
2278 2279 // where continuing to the next transition would surprise the caller,
2279 2280 // e.g., monitor entry.
2280 2281 //
2281 2282 // Returns the number of times that the thread self-suspended.
2282 2283 //
2283 2284 // Note: DO NOT call java_suspend_self() when you just want to block current
2284 2285 // thread. java_suspend_self() is the second stage of cooperative
2285 2286 // suspension for external suspend requests and should only be used
2286 2287 // to complete an external suspend request.
2287 2288 //
2288 2289 int JavaThread::java_suspend_self() {
2289 2290 int ret = 0;
2290 2291
2291 2292 // we are in the process of exiting so don't suspend
2292 2293 if (is_exiting()) {
2293 2294 clear_external_suspend();
2294 2295 return ret;
2295 2296 }
2296 2297
2297 2298 assert(_anchor.walkable() ||
2298 2299 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2299 2300 "must have walkable stack");
2300 2301
2301 2302 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2302 2303
2303 2304 assert(!this->is_ext_suspended(),
2304 2305 "a thread trying to self-suspend should not already be suspended");
2305 2306
2306 2307 if (this->is_suspend_equivalent()) {
2307 2308 // If we are self-suspending as a result of the lifting of a
2308 2309 // suspend equivalent condition, then the suspend_equivalent
2309 2310 // flag is not cleared until we set the ext_suspended flag so
2310 2311 // that wait_for_ext_suspend_completion() returns consistent
2311 2312 // results.
2312 2313 this->clear_suspend_equivalent();
2313 2314 }
2314 2315
2315 2316 // A racing resume may have cancelled us before we grabbed SR_lock
2316 2317 // above. Or another external suspend request could be waiting for us
2317 2318 // by the time we return from SR_lock()->wait(). The thread
2318 2319 // that requested the suspension may already be trying to walk our
2319 2320 // stack and if we return now, we can change the stack out from under
2320 2321 // it. This would be a "bad thing (TM)" and cause the stack walker
2321 2322 // to crash. We stay self-suspended until there are no more pending
2322 2323 // external suspend requests.
2323 2324 while (is_external_suspend()) {
2324 2325 ret++;
2325 2326 this->set_ext_suspended();
2326 2327
2327 2328 // _ext_suspended flag is cleared by java_resume()
2328 2329 while (is_ext_suspended()) {
2329 2330 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2330 2331 }
2331 2332 }
2332 2333
2333 2334 return ret;
2334 2335 }
2335 2336
2336 2337 #ifdef ASSERT
2337 2338 // verify the JavaThread has not yet been published in the Threads::list, and
2338 2339 // hence doesn't need protection from concurrent access at this stage
2339 2340 void JavaThread::verify_not_published() {
2340 2341 if (!Threads_lock->owned_by_self()) {
2341 2342 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2342 2343 assert( !Threads::includes(this),
2343 2344 "java thread shouldn't have been published yet!");
2344 2345 }
2345 2346 else {
2346 2347 assert( !Threads::includes(this),
2347 2348 "java thread shouldn't have been published yet!");
2348 2349 }
2349 2350 }
2350 2351 #endif
2351 2352
2352 2353 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2353 2354 // progress or when _suspend_flags is non-zero.
2354 2355 // Current thread needs to self-suspend if there is a suspend request and/or
2355 2356 // block if a safepoint is in progress.
2356 2357 // Async exception ISN'T checked.
2357 2358 // Note only the ThreadInVMfromNative transition can call this function
2358 2359 // directly and when thread state is _thread_in_native_trans
2359 2360 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2360 2361 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2361 2362
2362 2363 JavaThread *curJT = JavaThread::current();
2363 2364 bool do_self_suspend = thread->is_external_suspend();
2364 2365
2365 2366 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2366 2367
2367 2368 // If JNIEnv proxies are allowed, don't self-suspend if the target
2368 2369 // thread is not the current thread. In older versions of jdbx, jdbx
2369 2370 // threads could call into the VM with another thread's JNIEnv so we
2370 2371 // can be here operating on behalf of a suspended thread (4432884).
2371 2372 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2372 2373 JavaThreadState state = thread->thread_state();
2373 2374
2374 2375 // We mark this thread_blocked state as a suspend-equivalent so
2375 2376 // that a caller to is_ext_suspend_completed() won't be confused.
2376 2377 // The suspend-equivalent state is cleared by java_suspend_self().
2377 2378 thread->set_suspend_equivalent();
2378 2379
2379 2380 // If the safepoint code sees the _thread_in_native_trans state, it will
2380 2381 // wait until the thread changes to other thread state. There is no
2381 2382 // guarantee on how soon we can obtain the SR_lock and complete the
2382 2383 // self-suspend request. It would be a bad idea to let safepoint wait for
2383 2384 // too long. Temporarily change the state to _thread_blocked to
2384 2385 // let the VM thread know that this thread is ready for GC. The problem
2385 2386 // of changing thread state is that safepoint could happen just after
2386 2387 // java_suspend_self() returns after being resumed, and VM thread will
2387 2388 // see the _thread_blocked state. We must check for safepoint
2388 2389 // after restoring the state and make sure we won't leave while a safepoint
2389 2390 // is in progress.
2390 2391 thread->set_thread_state(_thread_blocked);
2391 2392 thread->java_suspend_self();
2392 2393 thread->set_thread_state(state);
2393 2394 // Make sure new state is seen by VM thread
2394 2395 if (os::is_MP()) {
2395 2396 if (UseMembar) {
2396 2397 // Force a fence between the write above and read below
2397 2398 OrderAccess::fence();
2398 2399 } else {
2399 2400 // Must use this rather than serialization page in particular on Windows
2400 2401 InterfaceSupport::serialize_memory(thread);
2401 2402 }
2402 2403 }
2403 2404 }
2404 2405
2405 2406 if (SafepointSynchronize::do_call_back()) {
2406 2407 // If we are safepointing, then block the caller which may not be
2407 2408 // the same as the target thread (see above).
2408 2409 SafepointSynchronize::block(curJT);
2409 2410 }
2410 2411
2411 2412 if (thread->is_deopt_suspend()) {
2412 2413 thread->clear_deopt_suspend();
2413 2414 RegisterMap map(thread, false);
2414 2415 frame f = thread->last_frame();
2415 2416 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2416 2417 f = f.sender(&map);
2417 2418 }
2418 2419 if (f.id() == thread->must_deopt_id()) {
2419 2420 thread->clear_must_deopt_id();
2420 2421 f.deoptimize(thread);
2421 2422 } else {
2422 2423 fatal("missed deoptimization!");
2423 2424 }
2424 2425 }
2425 2426 }
2426 2427
2427 2428 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2428 2429 // progress or when _suspend_flags is non-zero.
2429 2430 // Current thread needs to self-suspend if there is a suspend request and/or
2430 2431 // block if a safepoint is in progress.
2431 2432 // Also check for pending async exception (not including unsafe access error).
2432 2433 // Note only the native==>VM/Java barriers can call this function and when
2433 2434 // thread state is _thread_in_native_trans.
2434 2435 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2435 2436 check_safepoint_and_suspend_for_native_trans(thread);
2436 2437
2437 2438 if (thread->has_async_exception()) {
2438 2439 // We are in _thread_in_native_trans state, don't handle unsafe
2439 2440 // access error since that may block.
2440 2441 thread->check_and_handle_async_exceptions(false);
2441 2442 }
2442 2443 }
2443 2444
2444 2445 // This is a variant of the normal
2445 2446 // check_special_condition_for_native_trans with slightly different
2446 2447 // semantics for use by critical native wrappers. It does all the
2447 2448 // normal checks but also performs the transition back into
2448 2449 // thread_in_Java state. This is required so that critical natives
2449 2450 // can potentially block and perform a GC if they are the last thread
2450 2451 // exiting the GC_locker.
2451 2452 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2452 2453 check_special_condition_for_native_trans(thread);
2453 2454
2454 2455 // Finish the transition
2455 2456 thread->set_thread_state(_thread_in_Java);
2456 2457
2457 2458 if (thread->do_critical_native_unlock()) {
2458 2459 ThreadInVMfromJavaNoAsyncException tiv(thread);
2459 2460 GC_locker::unlock_critical(thread);
2460 2461 thread->clear_critical_native_unlock();
2461 2462 }
2462 2463 }
2463 2464
2464 2465 // We need to guarantee the Threads_lock here, since resumes are not
2465 2466 // allowed during safepoint synchronization
2466 2467 // Can only resume from an external suspension
2467 2468 void JavaThread::java_resume() {
2468 2469 assert_locked_or_safepoint(Threads_lock);
2469 2470
2470 2471 // Sanity check: thread is gone, has started exiting or the thread
2471 2472 // was not externally suspended.
2472 2473 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2473 2474 return;
2474 2475 }
2475 2476
2476 2477 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2477 2478
2478 2479 clear_external_suspend();
2479 2480
2480 2481 if (is_ext_suspended()) {
2481 2482 clear_ext_suspended();
2482 2483 SR_lock()->notify_all();
2483 2484 }
2484 2485 }
2485 2486
2486 2487 void JavaThread::create_stack_guard_pages() {
2487 2488 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2488 2489 address low_addr = stack_base() - stack_size();
2489 2490 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2490 2491
2491 2492 int allocate = os::allocate_stack_guard_pages();
2492 2493 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2493 2494
2494 2495 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2495 2496 warning("Attempt to allocate stack guard pages failed.");
2496 2497 return;
2497 2498 }
2498 2499
2499 2500 if (os::guard_memory((char *) low_addr, len)) {
2500 2501 _stack_guard_state = stack_guard_enabled;
2501 2502 } else {
2502 2503 warning("Attempt to protect stack guard pages failed.");
2503 2504 if (os::uncommit_memory((char *) low_addr, len)) {
2504 2505 warning("Attempt to deallocate stack guard pages failed.");
2505 2506 }
2506 2507 }
2507 2508 }
2508 2509
2509 2510 void JavaThread::remove_stack_guard_pages() {
2510 2511 assert(Thread::current() == this, "from different thread");
2511 2512 if (_stack_guard_state == stack_guard_unused) return;
2512 2513 address low_addr = stack_base() - stack_size();
2513 2514 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2514 2515
2515 2516 if (os::allocate_stack_guard_pages()) {
2516 2517 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2517 2518 _stack_guard_state = stack_guard_unused;
2518 2519 } else {
2519 2520 warning("Attempt to deallocate stack guard pages failed.");
2520 2521 }
2521 2522 } else {
2522 2523 if (_stack_guard_state == stack_guard_unused) return;
2523 2524 if (os::unguard_memory((char *) low_addr, len)) {
2524 2525 _stack_guard_state = stack_guard_unused;
2525 2526 } else {
2526 2527 warning("Attempt to unprotect stack guard pages failed.");
2527 2528 }
2528 2529 }
2529 2530 }
2530 2531
2531 2532 void JavaThread::enable_stack_yellow_zone() {
2532 2533 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2533 2534 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2534 2535
2535 2536 // The base notation is from the stacks point of view, growing downward.
2536 2537 // We need to adjust it to work correctly with guard_memory()
2537 2538 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2538 2539
2539 2540 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2540 2541 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2541 2542
2542 2543 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2543 2544 _stack_guard_state = stack_guard_enabled;
2544 2545 } else {
2545 2546 warning("Attempt to guard stack yellow zone failed.");
2546 2547 }
2547 2548 enable_register_stack_guard();
2548 2549 }
2549 2550
2550 2551 void JavaThread::disable_stack_yellow_zone() {
2551 2552 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2552 2553 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2553 2554
2554 2555 // Simply return if called for a thread that does not use guard pages.
2555 2556 if (_stack_guard_state == stack_guard_unused) return;
2556 2557
2557 2558 // The base notation is from the stacks point of view, growing downward.
2558 2559 // We need to adjust it to work correctly with guard_memory()
2559 2560 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2560 2561
2561 2562 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2562 2563 _stack_guard_state = stack_guard_yellow_disabled;
2563 2564 } else {
2564 2565 warning("Attempt to unguard stack yellow zone failed.");
2565 2566 }
2566 2567 disable_register_stack_guard();
2567 2568 }
2568 2569
2569 2570 void JavaThread::enable_stack_red_zone() {
2570 2571 // The base notation is from the stacks point of view, growing downward.
2571 2572 // We need to adjust it to work correctly with guard_memory()
2572 2573 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2573 2574 address base = stack_red_zone_base() - stack_red_zone_size();
2574 2575
2575 2576 guarantee(base < stack_base(),"Error calculating stack red zone");
2576 2577 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2577 2578
2578 2579 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2579 2580 warning("Attempt to guard stack red zone failed.");
2580 2581 }
2581 2582 }
2582 2583
2583 2584 void JavaThread::disable_stack_red_zone() {
2584 2585 // The base notation is from the stacks point of view, growing downward.
2585 2586 // We need to adjust it to work correctly with guard_memory()
2586 2587 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2587 2588 address base = stack_red_zone_base() - stack_red_zone_size();
2588 2589 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2589 2590 warning("Attempt to unguard stack red zone failed.");
2590 2591 }
2591 2592 }
2592 2593
2593 2594 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2594 2595 // ignore is there is no stack
2595 2596 if (!has_last_Java_frame()) return;
2596 2597 // traverse the stack frames. Starts from top frame.
2597 2598 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2598 2599 frame* fr = fst.current();
2599 2600 f(fr, fst.register_map());
2600 2601 }
2601 2602 }
2602 2603
2603 2604
2604 2605 #ifndef PRODUCT
2605 2606 // Deoptimization
2606 2607 // Function for testing deoptimization
2607 2608 void JavaThread::deoptimize() {
2608 2609 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2609 2610 StackFrameStream fst(this, UseBiasedLocking);
2610 2611 bool deopt = false; // Dump stack only if a deopt actually happens.
2611 2612 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2612 2613 // Iterate over all frames in the thread and deoptimize
2613 2614 for(; !fst.is_done(); fst.next()) {
2614 2615 if(fst.current()->can_be_deoptimized()) {
2615 2616
2616 2617 if (only_at) {
2617 2618 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2618 2619 // consists of comma or carriage return separated numbers so
2619 2620 // search for the current bci in that string.
2620 2621 address pc = fst.current()->pc();
2621 2622 nmethod* nm = (nmethod*) fst.current()->cb();
2622 2623 ScopeDesc* sd = nm->scope_desc_at( pc);
2623 2624 char buffer[8];
2624 2625 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2625 2626 size_t len = strlen(buffer);
2626 2627 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2627 2628 while (found != NULL) {
2628 2629 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2629 2630 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2630 2631 // Check that the bci found is bracketed by terminators.
2631 2632 break;
2632 2633 }
2633 2634 found = strstr(found + 1, buffer);
2634 2635 }
2635 2636 if (!found) {
2636 2637 continue;
2637 2638 }
2638 2639 }
2639 2640
2640 2641 if (DebugDeoptimization && !deopt) {
2641 2642 deopt = true; // One-time only print before deopt
2642 2643 tty->print_cr("[BEFORE Deoptimization]");
2643 2644 trace_frames();
2644 2645 trace_stack();
2645 2646 }
2646 2647 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2647 2648 }
2648 2649 }
2649 2650
2650 2651 if (DebugDeoptimization && deopt) {
2651 2652 tty->print_cr("[AFTER Deoptimization]");
2652 2653 trace_frames();
2653 2654 }
2654 2655 }
2655 2656
2656 2657
2657 2658 // Make zombies
2658 2659 void JavaThread::make_zombies() {
2659 2660 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2660 2661 if (fst.current()->can_be_deoptimized()) {
2661 2662 // it is a Java nmethod
2662 2663 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2663 2664 nm->make_not_entrant();
2664 2665 }
2665 2666 }
2666 2667 }
2667 2668 #endif // PRODUCT
2668 2669
2669 2670
2670 2671 void JavaThread::deoptimized_wrt_marked_nmethods() {
2671 2672 if (!has_last_Java_frame()) return;
2672 2673 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2673 2674 StackFrameStream fst(this, UseBiasedLocking);
2674 2675 for(; !fst.is_done(); fst.next()) {
2675 2676 if (fst.current()->should_be_deoptimized()) {
2676 2677 if (LogCompilation && xtty != NULL) {
2677 2678 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2678 2679 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2679 2680 this->name(), nm != NULL ? nm->compile_id() : -1);
2680 2681 }
2681 2682
2682 2683 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2683 2684 }
2684 2685 }
2685 2686 }
2686 2687
2687 2688
2688 2689 // GC support
2689 2690 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2690 2691
2691 2692 void JavaThread::gc_epilogue() {
2692 2693 frames_do(frame_gc_epilogue);
2693 2694 }
2694 2695
2695 2696
2696 2697 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2697 2698
2698 2699 void JavaThread::gc_prologue() {
2699 2700 frames_do(frame_gc_prologue);
2700 2701 }
2701 2702
2702 2703 // If the caller is a NamedThread, then remember, in the current scope,
2703 2704 // the given JavaThread in its _processed_thread field.
2704 2705 class RememberProcessedThread: public StackObj {
2705 2706 NamedThread* _cur_thr;
2706 2707 public:
2707 2708 RememberProcessedThread(JavaThread* jthr) {
2708 2709 Thread* thread = Thread::current();
2709 2710 if (thread->is_Named_thread()) {
2710 2711 _cur_thr = (NamedThread *)thread;
2711 2712 _cur_thr->set_processed_thread(jthr);
2712 2713 } else {
2713 2714 _cur_thr = NULL;
2714 2715 }
2715 2716 }
2716 2717
2717 2718 ~RememberProcessedThread() {
2718 2719 if (_cur_thr) {
2719 2720 _cur_thr->set_processed_thread(NULL);
2720 2721 }
2721 2722 }
2722 2723 };
2723 2724
2724 2725 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2725 2726 // Verify that the deferred card marks have been flushed.
2726 2727 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2727 2728
2728 2729 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2729 2730 // since there may be more than one thread using each ThreadProfiler.
2730 2731
2731 2732 // Traverse the GCHandles
2732 2733 Thread::oops_do(f, cld_f, cf);
2733 2734
2734 2735 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2735 2736 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2736 2737
2737 2738 if (has_last_Java_frame()) {
2738 2739 // Record JavaThread to GC thread
2739 2740 RememberProcessedThread rpt(this);
2740 2741
2741 2742 // Traverse the privileged stack
2742 2743 if (_privileged_stack_top != NULL) {
2743 2744 _privileged_stack_top->oops_do(f);
2744 2745 }
2745 2746
2746 2747 // traverse the registered growable array
2747 2748 if (_array_for_gc != NULL) {
2748 2749 for (int index = 0; index < _array_for_gc->length(); index++) {
2749 2750 f->do_oop(_array_for_gc->adr_at(index));
2750 2751 }
2751 2752 }
2752 2753
2753 2754 // Traverse the monitor chunks
2754 2755 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2755 2756 chunk->oops_do(f);
2756 2757 }
2757 2758
2758 2759 // Traverse the execution stack
2759 2760 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2760 2761 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2761 2762 }
2762 2763 }
2763 2764
2764 2765 // callee_target is never live across a gc point so NULL it here should
2765 2766 // it still contain a methdOop.
2766 2767
2767 2768 set_callee_target(NULL);
2768 2769
2769 2770 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2770 2771 // If we have deferred set_locals there might be oops waiting to be
2771 2772 // written
2772 2773 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2773 2774 if (list != NULL) {
2774 2775 for (int i = 0; i < list->length(); i++) {
2775 2776 list->at(i)->oops_do(f);
2776 2777 }
2777 2778 }
2778 2779
2779 2780 // Traverse instance variables at the end since the GC may be moving things
2780 2781 // around using this function
2781 2782 f->do_oop((oop*) &_threadObj);
2782 2783 f->do_oop((oop*) &_vm_result);
2783 2784 f->do_oop((oop*) &_exception_oop);
2784 2785 f->do_oop((oop*) &_pending_async_exception);
2785 2786
2786 2787 if (jvmti_thread_state() != NULL) {
2787 2788 jvmti_thread_state()->oops_do(f);
2788 2789 }
2789 2790 }
2790 2791
2791 2792 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2792 2793 Thread::nmethods_do(cf); // (super method is a no-op)
2793 2794
2794 2795 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2795 2796 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2796 2797
2797 2798 if (has_last_Java_frame()) {
2798 2799 // Traverse the execution stack
2799 2800 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2800 2801 fst.current()->nmethods_do(cf);
2801 2802 }
2802 2803 }
2803 2804 }
2804 2805
2805 2806 void JavaThread::metadata_do(void f(Metadata*)) {
2806 2807 Thread::metadata_do(f);
2807 2808 if (has_last_Java_frame()) {
2808 2809 // Traverse the execution stack to call f() on the methods in the stack
2809 2810 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2810 2811 fst.current()->metadata_do(f);
2811 2812 }
2812 2813 } else if (is_Compiler_thread()) {
2813 2814 // need to walk ciMetadata in current compile tasks to keep alive.
2814 2815 CompilerThread* ct = (CompilerThread*)this;
2815 2816 if (ct->env() != NULL) {
2816 2817 ct->env()->metadata_do(f);
2817 2818 }
2818 2819 }
2819 2820 }
2820 2821
2821 2822 // Printing
2822 2823 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2823 2824 switch (_thread_state) {
2824 2825 case _thread_uninitialized: return "_thread_uninitialized";
2825 2826 case _thread_new: return "_thread_new";
2826 2827 case _thread_new_trans: return "_thread_new_trans";
2827 2828 case _thread_in_native: return "_thread_in_native";
2828 2829 case _thread_in_native_trans: return "_thread_in_native_trans";
2829 2830 case _thread_in_vm: return "_thread_in_vm";
2830 2831 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2831 2832 case _thread_in_Java: return "_thread_in_Java";
2832 2833 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2833 2834 case _thread_blocked: return "_thread_blocked";
2834 2835 case _thread_blocked_trans: return "_thread_blocked_trans";
2835 2836 default: return "unknown thread state";
2836 2837 }
2837 2838 }
2838 2839
2839 2840 #ifndef PRODUCT
2840 2841 void JavaThread::print_thread_state_on(outputStream *st) const {
2841 2842 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2842 2843 };
2843 2844 void JavaThread::print_thread_state() const {
2844 2845 print_thread_state_on(tty);
2845 2846 };
2846 2847 #endif // PRODUCT
2847 2848
2848 2849 // Called by Threads::print() for VM_PrintThreads operation
2849 2850 void JavaThread::print_on(outputStream *st) const {
2850 2851 st->print("\"%s\" ", get_thread_name());
2851 2852 oop thread_oop = threadObj();
2852 2853 if (thread_oop != NULL) {
2853 2854 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2854 2855 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2855 2856 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2856 2857 }
2857 2858 Thread::print_on(st);
2858 2859 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2859 2860 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2860 2861 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2861 2862 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2862 2863 }
2863 2864 #ifndef PRODUCT
2864 2865 print_thread_state_on(st);
2865 2866 _safepoint_state->print_on(st);
2866 2867 #endif // PRODUCT
2867 2868 }
2868 2869
2869 2870 // Called by fatal error handler. The difference between this and
2870 2871 // JavaThread::print() is that we can't grab lock or allocate memory.
2871 2872 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2872 2873 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2873 2874 oop thread_obj = threadObj();
2874 2875 if (thread_obj != NULL) {
2875 2876 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2876 2877 }
2877 2878 st->print(" [");
2878 2879 st->print("%s", _get_thread_state_name(_thread_state));
2879 2880 if (osthread()) {
2880 2881 st->print(", id=%d", osthread()->thread_id());
2881 2882 }
2882 2883 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2883 2884 _stack_base - _stack_size, _stack_base);
2884 2885 st->print("]");
2885 2886 return;
2886 2887 }
2887 2888
2888 2889 // Verification
2889 2890
2890 2891 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2891 2892
2892 2893 void JavaThread::verify() {
2893 2894 // Verify oops in the thread.
2894 2895 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2895 2896
2896 2897 // Verify the stack frames.
2897 2898 frames_do(frame_verify);
2898 2899 }
2899 2900
2900 2901 // CR 6300358 (sub-CR 2137150)
2901 2902 // Most callers of this method assume that it can't return NULL but a
2902 2903 // thread may not have a name whilst it is in the process of attaching to
2903 2904 // the VM - see CR 6412693, and there are places where a JavaThread can be
2904 2905 // seen prior to having it's threadObj set (eg JNI attaching threads and
2905 2906 // if vm exit occurs during initialization). These cases can all be accounted
2906 2907 // for such that this method never returns NULL.
2907 2908 const char* JavaThread::get_thread_name() const {
2908 2909 #ifdef ASSERT
2909 2910 // early safepoints can hit while current thread does not yet have TLS
2910 2911 if (!SafepointSynchronize::is_at_safepoint()) {
2911 2912 Thread *cur = Thread::current();
2912 2913 if (!(cur->is_Java_thread() && cur == this)) {
2913 2914 // Current JavaThreads are allowed to get their own name without
2914 2915 // the Threads_lock.
2915 2916 assert_locked_or_safepoint(Threads_lock);
2916 2917 }
2917 2918 }
2918 2919 #endif // ASSERT
2919 2920 return get_thread_name_string();
2920 2921 }
2921 2922
2922 2923 // Returns a non-NULL representation of this thread's name, or a suitable
2923 2924 // descriptive string if there is no set name
2924 2925 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2925 2926 const char* name_str;
2926 2927 oop thread_obj = threadObj();
2927 2928 if (thread_obj != NULL) {
2928 2929 typeArrayOop name = java_lang_Thread::name(thread_obj);
2929 2930 if (name != NULL) {
2930 2931 if (buf == NULL) {
2931 2932 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2932 2933 }
2933 2934 else {
2934 2935 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2935 2936 }
2936 2937 }
2937 2938 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2938 2939 name_str = "<no-name - thread is attaching>";
2939 2940 }
2940 2941 else {
2941 2942 name_str = Thread::name();
2942 2943 }
2943 2944 }
2944 2945 else {
2945 2946 name_str = Thread::name();
2946 2947 }
2947 2948 assert(name_str != NULL, "unexpected NULL thread name");
2948 2949 return name_str;
2949 2950 }
2950 2951
2951 2952
2952 2953 const char* JavaThread::get_threadgroup_name() const {
2953 2954 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2954 2955 oop thread_obj = threadObj();
2955 2956 if (thread_obj != NULL) {
2956 2957 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2957 2958 if (thread_group != NULL) {
2958 2959 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2959 2960 // ThreadGroup.name can be null
2960 2961 if (name != NULL) {
2961 2962 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2962 2963 return str;
2963 2964 }
2964 2965 }
2965 2966 }
2966 2967 return NULL;
2967 2968 }
2968 2969
2969 2970 const char* JavaThread::get_parent_name() const {
2970 2971 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2971 2972 oop thread_obj = threadObj();
2972 2973 if (thread_obj != NULL) {
2973 2974 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2974 2975 if (thread_group != NULL) {
2975 2976 oop parent = java_lang_ThreadGroup::parent(thread_group);
2976 2977 if (parent != NULL) {
2977 2978 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2978 2979 // ThreadGroup.name can be null
2979 2980 if (name != NULL) {
2980 2981 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2981 2982 return str;
2982 2983 }
2983 2984 }
2984 2985 }
2985 2986 }
2986 2987 return NULL;
2987 2988 }
2988 2989
2989 2990 ThreadPriority JavaThread::java_priority() const {
2990 2991 oop thr_oop = threadObj();
2991 2992 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2992 2993 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2993 2994 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2994 2995 return priority;
2995 2996 }
2996 2997
2997 2998 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2998 2999
2999 3000 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
3000 3001 // Link Java Thread object <-> C++ Thread
3001 3002
3002 3003 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3003 3004 // and put it into a new Handle. The Handle "thread_oop" can then
3004 3005 // be used to pass the C++ thread object to other methods.
3005 3006
3006 3007 // Set the Java level thread object (jthread) field of the
3007 3008 // new thread (a JavaThread *) to C++ thread object using the
3008 3009 // "thread_oop" handle.
3009 3010
3010 3011 // Set the thread field (a JavaThread *) of the
3011 3012 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3012 3013
3013 3014 Handle thread_oop(Thread::current(),
3014 3015 JNIHandles::resolve_non_null(jni_thread));
3015 3016 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3016 3017 "must be initialized");
3017 3018 set_threadObj(thread_oop());
3018 3019 java_lang_Thread::set_thread(thread_oop(), this);
3019 3020
3020 3021 if (prio == NoPriority) {
3021 3022 prio = java_lang_Thread::priority(thread_oop());
3022 3023 assert(prio != NoPriority, "A valid priority should be present");
3023 3024 }
3024 3025
3025 3026 // Push the Java priority down to the native thread; needs Threads_lock
3026 3027 Thread::set_priority(this, prio);
3027 3028
3028 3029 prepare_ext();
3029 3030
3030 3031 // Add the new thread to the Threads list and set it in motion.
3031 3032 // We must have threads lock in order to call Threads::add.
3032 3033 // It is crucial that we do not block before the thread is
3033 3034 // added to the Threads list for if a GC happens, then the java_thread oop
3034 3035 // will not be visited by GC.
3035 3036 Threads::add(this);
3036 3037 }
3037 3038
3038 3039 oop JavaThread::current_park_blocker() {
3039 3040 // Support for JSR-166 locks
3040 3041 oop thread_oop = threadObj();
3041 3042 if (thread_oop != NULL &&
3042 3043 JDK_Version::current().supports_thread_park_blocker()) {
3043 3044 return java_lang_Thread::park_blocker(thread_oop);
3044 3045 }
3045 3046 return NULL;
3046 3047 }
3047 3048
3048 3049
3049 3050 void JavaThread::print_stack_on(outputStream* st) {
3050 3051 if (!has_last_Java_frame()) return;
3051 3052 ResourceMark rm;
3052 3053 HandleMark hm;
3053 3054
3054 3055 RegisterMap reg_map(this);
3055 3056 vframe* start_vf = last_java_vframe(®_map);
3056 3057 int count = 0;
3057 3058 for (vframe* f = start_vf; f; f = f->sender() ) {
3058 3059 if (f->is_java_frame()) {
3059 3060 javaVFrame* jvf = javaVFrame::cast(f);
3060 3061 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3061 3062
3062 3063 // Print out lock information
3063 3064 if (JavaMonitorsInStackTrace) {
3064 3065 jvf->print_lock_info_on(st, count);
3065 3066 }
3066 3067 } else {
3067 3068 // Ignore non-Java frames
3068 3069 }
3069 3070
3070 3071 // Bail-out case for too deep stacks
3071 3072 count++;
3072 3073 if (MaxJavaStackTraceDepth == count) return;
3073 3074 }
3074 3075 }
3075 3076
3076 3077
3077 3078 // JVMTI PopFrame support
3078 3079 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3079 3080 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3080 3081 if (in_bytes(size_in_bytes) != 0) {
3081 3082 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3082 3083 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3083 3084 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3084 3085 }
3085 3086 }
3086 3087
3087 3088 void* JavaThread::popframe_preserved_args() {
3088 3089 return _popframe_preserved_args;
3089 3090 }
3090 3091
3091 3092 ByteSize JavaThread::popframe_preserved_args_size() {
3092 3093 return in_ByteSize(_popframe_preserved_args_size);
3093 3094 }
3094 3095
3095 3096 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3096 3097 int sz = in_bytes(popframe_preserved_args_size());
3097 3098 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3098 3099 return in_WordSize(sz / wordSize);
3099 3100 }
3100 3101
3101 3102 void JavaThread::popframe_free_preserved_args() {
3102 3103 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3103 3104 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3104 3105 _popframe_preserved_args = NULL;
3105 3106 _popframe_preserved_args_size = 0;
3106 3107 }
3107 3108
3108 3109 #ifndef PRODUCT
3109 3110
3110 3111 void JavaThread::trace_frames() {
3111 3112 tty->print_cr("[Describe stack]");
3112 3113 int frame_no = 1;
3113 3114 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3114 3115 tty->print(" %d. ", frame_no++);
3115 3116 fst.current()->print_value_on(tty,this);
3116 3117 tty->cr();
3117 3118 }
3118 3119 }
3119 3120
3120 3121 class PrintAndVerifyOopClosure: public OopClosure {
3121 3122 protected:
3122 3123 template <class T> inline void do_oop_work(T* p) {
3123 3124 oop obj = oopDesc::load_decode_heap_oop(p);
3124 3125 if (obj == NULL) return;
3125 3126 tty->print(INTPTR_FORMAT ": ", p);
3126 3127 if (obj->is_oop_or_null()) {
3127 3128 if (obj->is_objArray()) {
3128 3129 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3129 3130 } else {
3130 3131 obj->print();
3131 3132 }
3132 3133 } else {
3133 3134 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3134 3135 }
3135 3136 tty->cr();
3136 3137 }
3137 3138 public:
3138 3139 virtual void do_oop(oop* p) { do_oop_work(p); }
3139 3140 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3140 3141 };
3141 3142
3142 3143
3143 3144 static void oops_print(frame* f, const RegisterMap *map) {
3144 3145 PrintAndVerifyOopClosure print;
3145 3146 f->print_value();
3146 3147 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3147 3148 }
3148 3149
3149 3150 // Print our all the locations that contain oops and whether they are
3150 3151 // valid or not. This useful when trying to find the oldest frame
3151 3152 // where an oop has gone bad since the frame walk is from youngest to
3152 3153 // oldest.
3153 3154 void JavaThread::trace_oops() {
3154 3155 tty->print_cr("[Trace oops]");
3155 3156 frames_do(oops_print);
3156 3157 }
3157 3158
3158 3159
3159 3160 #ifdef ASSERT
3160 3161 // Print or validate the layout of stack frames
3161 3162 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3162 3163 ResourceMark rm;
3163 3164 PRESERVE_EXCEPTION_MARK;
3164 3165 FrameValues values;
3165 3166 int frame_no = 0;
3166 3167 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3167 3168 fst.current()->describe(values, ++frame_no);
3168 3169 if (depth == frame_no) break;
3169 3170 }
3170 3171 if (validate_only) {
3171 3172 values.validate();
3172 3173 } else {
3173 3174 tty->print_cr("[Describe stack layout]");
3174 3175 values.print(this);
3175 3176 }
3176 3177 }
3177 3178 #endif
3178 3179
3179 3180 void JavaThread::trace_stack_from(vframe* start_vf) {
3180 3181 ResourceMark rm;
3181 3182 int vframe_no = 1;
3182 3183 for (vframe* f = start_vf; f; f = f->sender() ) {
3183 3184 if (f->is_java_frame()) {
3184 3185 javaVFrame::cast(f)->print_activation(vframe_no++);
3185 3186 } else {
3186 3187 f->print();
3187 3188 }
3188 3189 if (vframe_no > StackPrintLimit) {
3189 3190 tty->print_cr("...<more frames>...");
3190 3191 return;
3191 3192 }
3192 3193 }
3193 3194 }
3194 3195
3195 3196
3196 3197 void JavaThread::trace_stack() {
3197 3198 if (!has_last_Java_frame()) return;
3198 3199 ResourceMark rm;
3199 3200 HandleMark hm;
3200 3201 RegisterMap reg_map(this);
3201 3202 trace_stack_from(last_java_vframe(®_map));
3202 3203 }
3203 3204
3204 3205
3205 3206 #endif // PRODUCT
3206 3207
3207 3208
3208 3209 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3209 3210 assert(reg_map != NULL, "a map must be given");
3210 3211 frame f = last_frame();
3211 3212 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3212 3213 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3213 3214 }
3214 3215 return NULL;
3215 3216 }
3216 3217
3217 3218
3218 3219 Klass* JavaThread::security_get_caller_class(int depth) {
3219 3220 vframeStream vfst(this);
3220 3221 vfst.security_get_caller_frame(depth);
3221 3222 if (!vfst.at_end()) {
3222 3223 return vfst.method()->method_holder();
3223 3224 }
3224 3225 return NULL;
3225 3226 }
3226 3227
3227 3228 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3228 3229 assert(thread->is_Compiler_thread(), "must be compiler thread");
3229 3230 CompileBroker::compiler_thread_loop();
3230 3231 }
3231 3232
3232 3233 // Create a CompilerThread
3233 3234 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3234 3235 : JavaThread(&compiler_thread_entry) {
3235 3236 _env = NULL;
3236 3237 _log = NULL;
3237 3238 _task = NULL;
3238 3239 _queue = queue;
3239 3240 _counters = counters;
3240 3241 _buffer_blob = NULL;
3241 3242 _scanned_nmethod = NULL;
3242 3243 _compiler = NULL;
3243 3244
3244 3245 #ifndef PRODUCT
3245 3246 _ideal_graph_printer = NULL;
3246 3247 #endif
3247 3248 }
3248 3249
3249 3250 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3250 3251 JavaThread::oops_do(f, cld_f, cf);
3251 3252 if (_scanned_nmethod != NULL && cf != NULL) {
3252 3253 // Safepoints can occur when the sweeper is scanning an nmethod so
3253 3254 // process it here to make sure it isn't unloaded in the middle of
3254 3255 // a scan.
3255 3256 cf->do_code_blob(_scanned_nmethod);
3256 3257 }
3257 3258 }
3258 3259
3259 3260
3260 3261 // ======= Threads ========
3261 3262
3262 3263 // The Threads class links together all active threads, and provides
3263 3264 // operations over all threads. It is protected by its own Mutex
3264 3265 // lock, which is also used in other contexts to protect thread
3265 3266 // operations from having the thread being operated on from exiting
3266 3267 // and going away unexpectedly (e.g., safepoint synchronization)
3267 3268
3268 3269 JavaThread* Threads::_thread_list = NULL;
3269 3270 int Threads::_number_of_threads = 0;
3270 3271 int Threads::_number_of_non_daemon_threads = 0;
3271 3272 int Threads::_return_code = 0;
3272 3273 size_t JavaThread::_stack_size_at_create = 0;
3273 3274 #ifdef ASSERT
3274 3275 bool Threads::_vm_complete = false;
3275 3276 #endif
3276 3277
3277 3278 // All JavaThreads
3278 3279 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3279 3280
3280 3281 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3281 3282 void Threads::threads_do(ThreadClosure* tc) {
3282 3283 assert_locked_or_safepoint(Threads_lock);
3283 3284 // ALL_JAVA_THREADS iterates through all JavaThreads
3284 3285 ALL_JAVA_THREADS(p) {
3285 3286 tc->do_thread(p);
3286 3287 }
3287 3288 // Someday we could have a table or list of all non-JavaThreads.
3288 3289 // For now, just manually iterate through them.
3289 3290 tc->do_thread(VMThread::vm_thread());
3290 3291 Universe::heap()->gc_threads_do(tc);
3291 3292 WatcherThread *wt = WatcherThread::watcher_thread();
3292 3293 // Strictly speaking, the following NULL check isn't sufficient to make sure
3293 3294 // the data for WatcherThread is still valid upon being examined. However,
3294 3295 // considering that WatchThread terminates when the VM is on the way to
3295 3296 // exit at safepoint, the chance of the above is extremely small. The right
3296 3297 // way to prevent termination of WatcherThread would be to acquire
3297 3298 // Terminator_lock, but we can't do that without violating the lock rank
3298 3299 // checking in some cases.
3299 3300 if (wt != NULL)
3300 3301 tc->do_thread(wt);
3301 3302
3302 3303 // If CompilerThreads ever become non-JavaThreads, add them here
3303 3304 }
3304 3305
3305 3306 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3306 3307
3307 3308 extern void JDK_Version_init();
3308 3309
3309 3310 // Check version
3310 3311 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3311 3312
3312 3313 // Initialize the output stream module
3313 3314 ostream_init();
3314 3315
3315 3316 // Process java launcher properties.
3316 3317 Arguments::process_sun_java_launcher_properties(args);
3317 3318
3318 3319 // Initialize the os module before using TLS
3319 3320 os::init();
3320 3321
3321 3322 // Initialize system properties.
3322 3323 Arguments::init_system_properties();
3323 3324
3324 3325 // So that JDK version can be used as a discrimintor when parsing arguments
3325 3326 JDK_Version_init();
3326 3327
3327 3328 // Update/Initialize System properties after JDK version number is known
3328 3329 Arguments::init_version_specific_system_properties();
3329 3330
3330 3331 // Parse arguments
3331 3332 jint parse_result = Arguments::parse(args);
3332 3333 if (parse_result != JNI_OK) return parse_result;
3333 3334
3334 3335 os::init_before_ergo();
3335 3336
3336 3337 jint ergo_result = Arguments::apply_ergo();
3337 3338 if (ergo_result != JNI_OK) return ergo_result;
3338 3339
3339 3340 if (PauseAtStartup) {
3340 3341 os::pause();
3341 3342 }
3342 3343
3343 3344 #ifndef USDT2
3344 3345 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3345 3346 #else /* USDT2 */
3346 3347 HOTSPOT_VM_INIT_BEGIN();
3347 3348 #endif /* USDT2 */
3348 3349
3349 3350 // Record VM creation timing statistics
3350 3351 TraceVmCreationTime create_vm_timer;
3351 3352 create_vm_timer.start();
3352 3353
3353 3354 // Timing (must come after argument parsing)
3354 3355 TraceTime timer("Create VM", TraceStartupTime);
3355 3356
3356 3357 // Initialize the os module after parsing the args
3357 3358 jint os_init_2_result = os::init_2();
3358 3359 if (os_init_2_result != JNI_OK) return os_init_2_result;
3359 3360
3360 3361 jint adjust_after_os_result = Arguments::adjust_after_os();
3361 3362 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3362 3363
3363 3364 // intialize TLS
3364 3365 ThreadLocalStorage::init();
3365 3366
3366 3367 // Initialize output stream logging
3367 3368 ostream_init_log();
3368 3369
3369 3370 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3370 3371 // Must be before create_vm_init_agents()
3371 3372 if (Arguments::init_libraries_at_startup()) {
3372 3373 convert_vm_init_libraries_to_agents();
3373 3374 }
3374 3375
3375 3376 // Launch -agentlib/-agentpath and converted -Xrun agents
3376 3377 if (Arguments::init_agents_at_startup()) {
3377 3378 create_vm_init_agents();
3378 3379 }
3379 3380
3380 3381 // Initialize Threads state
3381 3382 _thread_list = NULL;
3382 3383 _number_of_threads = 0;
3383 3384 _number_of_non_daemon_threads = 0;
3384 3385
3385 3386 // Initialize global data structures and create system classes in heap
3386 3387 vm_init_globals();
3387 3388
3388 3389 // Attach the main thread to this os thread
3389 3390 JavaThread* main_thread = new JavaThread();
3390 3391 main_thread->set_thread_state(_thread_in_vm);
3391 3392 // must do this before set_active_handles and initialize_thread_local_storage
3392 3393 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3393 3394 // change the stack size recorded here to one based on the java thread
3394 3395 // stacksize. This adjusted size is what is used to figure the placement
3395 3396 // of the guard pages.
3396 3397 main_thread->record_stack_base_and_size();
3397 3398 main_thread->initialize_thread_local_storage();
3398 3399
3399 3400 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3400 3401
3401 3402 if (!main_thread->set_as_starting_thread()) {
3402 3403 vm_shutdown_during_initialization(
3403 3404 "Failed necessary internal allocation. Out of swap space");
3404 3405 delete main_thread;
3405 3406 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3406 3407 return JNI_ENOMEM;
3407 3408 }
3408 3409
3409 3410 // Enable guard page *after* os::create_main_thread(), otherwise it would
3410 3411 // crash Linux VM, see notes in os_linux.cpp.
3411 3412 main_thread->create_stack_guard_pages();
3412 3413
3413 3414 // Initialize Java-Level synchronization subsystem
3414 3415 ObjectMonitor::Initialize() ;
3415 3416
3416 3417 // Initialize global modules
3417 3418 jint status = init_globals();
3418 3419 if (status != JNI_OK) {
3419 3420 delete main_thread;
3420 3421 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3421 3422 return status;
3422 3423 }
3423 3424
3424 3425 // Should be done after the heap is fully created
3425 3426 main_thread->cache_global_variables();
3426 3427
3427 3428 HandleMark hm;
3428 3429
3429 3430 { MutexLocker mu(Threads_lock);
3430 3431 Threads::add(main_thread);
3431 3432 }
3432 3433
3433 3434 // Any JVMTI raw monitors entered in onload will transition into
3434 3435 // real raw monitor. VM is setup enough here for raw monitor enter.
3435 3436 JvmtiExport::transition_pending_onload_raw_monitors();
3436 3437
3437 3438 // Create the VMThread
3438 3439 { TraceTime timer("Start VMThread", TraceStartupTime);
3439 3440 VMThread::create();
3440 3441 Thread* vmthread = VMThread::vm_thread();
3441 3442
3442 3443 if (!os::create_thread(vmthread, os::vm_thread))
3443 3444 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3444 3445
3445 3446 // Wait for the VM thread to become ready, and VMThread::run to initialize
3446 3447 // Monitors can have spurious returns, must always check another state flag
3447 3448 {
3448 3449 MutexLocker ml(Notify_lock);
3449 3450 os::start_thread(vmthread);
3450 3451 while (vmthread->active_handles() == NULL) {
3451 3452 Notify_lock->wait();
3452 3453 }
3453 3454 }
3454 3455 }
3455 3456
3456 3457 assert (Universe::is_fully_initialized(), "not initialized");
3457 3458 if (VerifyDuringStartup) {
3458 3459 // Make sure we're starting with a clean slate.
3459 3460 VM_Verify verify_op;
3460 3461 VMThread::execute(&verify_op);
3461 3462 }
3462 3463
3463 3464 EXCEPTION_MARK;
3464 3465
3465 3466 // At this point, the Universe is initialized, but we have not executed
3466 3467 // any byte code. Now is a good time (the only time) to dump out the
3467 3468 // internal state of the JVM for sharing.
3468 3469 if (DumpSharedSpaces) {
3469 3470 MetaspaceShared::preload_and_dump(CHECK_0);
3470 3471 ShouldNotReachHere();
3471 3472 }
3472 3473
3473 3474 // Always call even when there are not JVMTI environments yet, since environments
3474 3475 // may be attached late and JVMTI must track phases of VM execution
3475 3476 JvmtiExport::enter_start_phase();
3476 3477
3477 3478 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3478 3479 JvmtiExport::post_vm_start();
3479 3480
3480 3481 {
3481 3482 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3482 3483
3483 3484 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3484 3485 create_vm_init_libraries();
3485 3486 }
3486 3487
3487 3488 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3488 3489
3489 3490 // Initialize java_lang.System (needed before creating the thread)
3490 3491 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3491 3492 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3492 3493 Handle thread_group = create_initial_thread_group(CHECK_0);
3493 3494 Universe::set_main_thread_group(thread_group());
3494 3495 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3495 3496 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3496 3497 main_thread->set_threadObj(thread_object);
3497 3498 // Set thread status to running since main thread has
3498 3499 // been started and running.
3499 3500 java_lang_Thread::set_thread_status(thread_object,
3500 3501 java_lang_Thread::RUNNABLE);
3501 3502
3502 3503 // The VM creates & returns objects of this class. Make sure it's initialized.
3503 3504 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3504 3505
3505 3506 // The VM preresolves methods to these classes. Make sure that they get initialized
3506 3507 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3507 3508 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3508 3509 call_initializeSystemClass(CHECK_0);
3509 3510
3510 3511 // get the Java runtime name after java.lang.System is initialized
3511 3512 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3512 3513 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3513 3514
3514 3515 // an instance of OutOfMemory exception has been allocated earlier
3515 3516 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3516 3517 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3517 3518 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3518 3519 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3519 3520 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3520 3521 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3521 3522 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3522 3523 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3523 3524 }
3524 3525
3525 3526 // See : bugid 4211085.
3526 3527 // Background : the static initializer of java.lang.Compiler tries to read
3527 3528 // property"java.compiler" and read & write property "java.vm.info".
3528 3529 // When a security manager is installed through the command line
3529 3530 // option "-Djava.security.manager", the above properties are not
3530 3531 // readable and the static initializer for java.lang.Compiler fails
3531 3532 // resulting in a NoClassDefFoundError. This can happen in any
3532 3533 // user code which calls methods in java.lang.Compiler.
3533 3534 // Hack : the hack is to pre-load and initialize this class, so that only
3534 3535 // system domains are on the stack when the properties are read.
3535 3536 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3536 3537 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3537 3538 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3538 3539 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3539 3540 // Once that is done, we should remove this hack.
3540 3541 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3541 3542
3542 3543 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3543 3544 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3544 3545 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3545 3546 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3546 3547 // This should also be taken out as soon as 4211383 gets fixed.
3547 3548 reset_vm_info_property(CHECK_0);
3548 3549
3549 3550 quicken_jni_functions();
3550 3551
3551 3552 // Must be run after init_ft which initializes ft_enabled
3552 3553 if (TRACE_INITIALIZE() != JNI_OK) {
3553 3554 vm_exit_during_initialization("Failed to initialize tracing backend");
3554 3555 }
3555 3556
3556 3557 // Set flag that basic initialization has completed. Used by exceptions and various
3557 3558 // debug stuff, that does not work until all basic classes have been initialized.
3558 3559 set_init_completed();
3559 3560
3560 3561 Metaspace::post_initialize();
3561 3562
3562 3563 #ifndef USDT2
3563 3564 HS_DTRACE_PROBE(hotspot, vm__init__end);
3564 3565 #else /* USDT2 */
3565 3566 HOTSPOT_VM_INIT_END();
3566 3567 #endif /* USDT2 */
3567 3568
3568 3569 // record VM initialization completion time
3569 3570 #if INCLUDE_MANAGEMENT
3570 3571 Management::record_vm_init_completed();
3571 3572 #endif // INCLUDE_MANAGEMENT
3572 3573
3573 3574 // Compute system loader. Note that this has to occur after set_init_completed, since
3574 3575 // valid exceptions may be thrown in the process.
3575 3576 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3576 3577 // set_init_completed has just been called, causing exceptions not to be shortcut
3577 3578 // anymore. We call vm_exit_during_initialization directly instead.
3578 3579 SystemDictionary::compute_java_system_loader(THREAD);
3579 3580 if (HAS_PENDING_EXCEPTION) {
3580 3581 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3581 3582 }
3582 3583
3583 3584 #if INCLUDE_ALL_GCS
3584 3585 // Support for ConcurrentMarkSweep. This should be cleaned up
3585 3586 // and better encapsulated. The ugly nested if test would go away
3586 3587 // once things are properly refactored. XXX YSR
3587 3588 if (UseConcMarkSweepGC || UseG1GC) {
3588 3589 if (UseConcMarkSweepGC) {
3589 3590 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3590 3591 } else {
3591 3592 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3592 3593 }
3593 3594 if (HAS_PENDING_EXCEPTION) {
3594 3595 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3595 3596 }
3596 3597 }
3597 3598 #endif // INCLUDE_ALL_GCS
3598 3599
3599 3600 // Always call even when there are not JVMTI environments yet, since environments
3600 3601 // may be attached late and JVMTI must track phases of VM execution
3601 3602 JvmtiExport::enter_live_phase();
3602 3603
3603 3604 // Signal Dispatcher needs to be started before VMInit event is posted
3604 3605 os::signal_init();
3605 3606
3606 3607 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3607 3608 if (!DisableAttachMechanism) {
3608 3609 AttachListener::vm_start();
3609 3610 if (StartAttachListener || AttachListener::init_at_startup()) {
3610 3611 AttachListener::init();
3611 3612 }
3612 3613 }
3613 3614
3614 3615 // Launch -Xrun agents
3615 3616 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3616 3617 // back-end can launch with -Xdebug -Xrunjdwp.
3617 3618 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3618 3619 create_vm_init_libraries();
3619 3620 }
3620 3621
3621 3622 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3622 3623 JvmtiExport::post_vm_initialized();
3623 3624
3624 3625 if (TRACE_START() != JNI_OK) {
3625 3626 vm_exit_during_initialization("Failed to start tracing backend.");
3626 3627 }
3627 3628
3628 3629 if (CleanChunkPoolAsync) {
3629 3630 Chunk::start_chunk_pool_cleaner_task();
3630 3631 }
3631 3632
3632 3633 // initialize compiler(s)
3633 3634 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3634 3635 CompileBroker::compilation_init();
3635 3636 #endif
3636 3637
3637 3638 if (EnableInvokeDynamic) {
3638 3639 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3639 3640 // It is done after compilers are initialized, because otherwise compilations of
3640 3641 // signature polymorphic MH intrinsics can be missed
3641 3642 // (see SystemDictionary::find_method_handle_intrinsic).
3642 3643 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3643 3644 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3644 3645 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3645 3646 }
3646 3647
3647 3648 #if INCLUDE_MANAGEMENT
3648 3649 Management::initialize(THREAD);
3649 3650 #endif // INCLUDE_MANAGEMENT
3650 3651
3651 3652 if (HAS_PENDING_EXCEPTION) {
3652 3653 // management agent fails to start possibly due to
3653 3654 // configuration problem and is responsible for printing
3654 3655 // stack trace if appropriate. Simply exit VM.
3655 3656 vm_exit(1);
3656 3657 }
3657 3658
3658 3659 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3659 3660 if (MemProfiling) MemProfiler::engage();
3660 3661 StatSampler::engage();
3661 3662 if (CheckJNICalls) JniPeriodicChecker::engage();
3662 3663
3663 3664 BiasedLocking::init();
3664 3665
3665 3666 #if INCLUDE_RTM_OPT
3666 3667 RTMLockingCounters::init();
3667 3668 #endif
3668 3669
3669 3670 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3670 3671 call_postVMInitHook(THREAD);
3671 3672 // The Java side of PostVMInitHook.run must deal with all
3672 3673 // exceptions and provide means of diagnosis.
3673 3674 if (HAS_PENDING_EXCEPTION) {
3674 3675 CLEAR_PENDING_EXCEPTION;
3675 3676 }
3676 3677 }
3677 3678
3678 3679 {
3679 3680 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3680 3681 // Make sure the watcher thread can be started by WatcherThread::start()
3681 3682 // or by dynamic enrollment.
3682 3683 WatcherThread::make_startable();
3683 3684 // Start up the WatcherThread if there are any periodic tasks
3684 3685 // NOTE: All PeriodicTasks should be registered by now. If they
3685 3686 // aren't, late joiners might appear to start slowly (we might
3686 3687 // take a while to process their first tick).
3687 3688 if (PeriodicTask::num_tasks() > 0) {
3688 3689 WatcherThread::start();
3689 3690 }
3690 3691 }
3691 3692
3692 3693 // Give os specific code one last chance to start
3693 3694 os::init_3();
3694 3695
3695 3696 create_vm_timer.end();
3696 3697 #ifdef ASSERT
3697 3698 _vm_complete = true;
3698 3699 #endif
3699 3700 return JNI_OK;
3700 3701 }
3701 3702
3702 3703 // type for the Agent_OnLoad and JVM_OnLoad entry points
3703 3704 extern "C" {
3704 3705 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3705 3706 }
3706 3707 // Find a command line agent library and return its entry point for
3707 3708 // -agentlib: -agentpath: -Xrun
3708 3709 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3709 3710 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3710 3711 OnLoadEntry_t on_load_entry = NULL;
3711 3712 void *library = NULL;
3712 3713
3713 3714 if (!agent->valid()) {
3714 3715 char buffer[JVM_MAXPATHLEN];
3715 3716 char ebuf[1024];
3716 3717 const char *name = agent->name();
3717 3718 const char *msg = "Could not find agent library ";
3718 3719
3719 3720 // First check to see if agent is statically linked into executable
3720 3721 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3721 3722 library = agent->os_lib();
3722 3723 } else if (agent->is_absolute_path()) {
3723 3724 library = os::dll_load(name, ebuf, sizeof ebuf);
3724 3725 if (library == NULL) {
3725 3726 const char *sub_msg = " in absolute path, with error: ";
3726 3727 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3727 3728 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3728 3729 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3729 3730 // If we can't find the agent, exit.
3730 3731 vm_exit_during_initialization(buf, NULL);
3731 3732 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3732 3733 }
3733 3734 } else {
3734 3735 // Try to load the agent from the standard dll directory
3735 3736 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3736 3737 name)) {
3737 3738 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3738 3739 }
3739 3740 if (library == NULL) { // Try the local directory
3740 3741 char ns[1] = {0};
3741 3742 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3742 3743 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3743 3744 }
3744 3745 if (library == NULL) {
3745 3746 const char *sub_msg = " on the library path, with error: ";
3746 3747 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3747 3748 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3748 3749 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3749 3750 // If we can't find the agent, exit.
3750 3751 vm_exit_during_initialization(buf, NULL);
3751 3752 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3752 3753 }
3753 3754 }
3754 3755 }
3755 3756 agent->set_os_lib(library);
3756 3757 agent->set_valid();
3757 3758 }
3758 3759
3759 3760 // Find the OnLoad function.
3760 3761 on_load_entry =
3761 3762 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3762 3763 false,
3763 3764 on_load_symbols,
3764 3765 num_symbol_entries));
3765 3766 return on_load_entry;
3766 3767 }
3767 3768
3768 3769 // Find the JVM_OnLoad entry point
3769 3770 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3770 3771 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3771 3772 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3772 3773 }
3773 3774
3774 3775 // Find the Agent_OnLoad entry point
3775 3776 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3776 3777 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3777 3778 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3778 3779 }
3779 3780
3780 3781 // For backwards compatibility with -Xrun
3781 3782 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3782 3783 // treated like -agentpath:
3783 3784 // Must be called before agent libraries are created
3784 3785 void Threads::convert_vm_init_libraries_to_agents() {
3785 3786 AgentLibrary* agent;
3786 3787 AgentLibrary* next;
3787 3788
3788 3789 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3789 3790 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3790 3791 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3791 3792
3792 3793 // If there is an JVM_OnLoad function it will get called later,
3793 3794 // otherwise see if there is an Agent_OnLoad
3794 3795 if (on_load_entry == NULL) {
3795 3796 on_load_entry = lookup_agent_on_load(agent);
3796 3797 if (on_load_entry != NULL) {
3797 3798 // switch it to the agent list -- so that Agent_OnLoad will be called,
3798 3799 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3799 3800 Arguments::convert_library_to_agent(agent);
3800 3801 } else {
3801 3802 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3802 3803 }
3803 3804 }
3804 3805 }
3805 3806 }
3806 3807
3807 3808 // Create agents for -agentlib: -agentpath: and converted -Xrun
3808 3809 // Invokes Agent_OnLoad
3809 3810 // Called very early -- before JavaThreads exist
3810 3811 void Threads::create_vm_init_agents() {
3811 3812 extern struct JavaVM_ main_vm;
3812 3813 AgentLibrary* agent;
3813 3814
3814 3815 JvmtiExport::enter_onload_phase();
3815 3816
3816 3817 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3817 3818 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3818 3819
3819 3820 if (on_load_entry != NULL) {
3820 3821 // Invoke the Agent_OnLoad function
3821 3822 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3822 3823 if (err != JNI_OK) {
3823 3824 vm_exit_during_initialization("agent library failed to init", agent->name());
3824 3825 }
3825 3826 } else {
3826 3827 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3827 3828 }
3828 3829 }
3829 3830 JvmtiExport::enter_primordial_phase();
3830 3831 }
3831 3832
3832 3833 extern "C" {
3833 3834 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3834 3835 }
3835 3836
3836 3837 void Threads::shutdown_vm_agents() {
3837 3838 // Send any Agent_OnUnload notifications
3838 3839 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3839 3840 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3840 3841 extern struct JavaVM_ main_vm;
3841 3842 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3842 3843
3843 3844 // Find the Agent_OnUnload function.
3844 3845 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3845 3846 os::find_agent_function(agent,
3846 3847 false,
3847 3848 on_unload_symbols,
3848 3849 num_symbol_entries));
3849 3850
3850 3851 // Invoke the Agent_OnUnload function
3851 3852 if (unload_entry != NULL) {
3852 3853 JavaThread* thread = JavaThread::current();
3853 3854 ThreadToNativeFromVM ttn(thread);
3854 3855 HandleMark hm(thread);
3855 3856 (*unload_entry)(&main_vm);
3856 3857 }
3857 3858 }
3858 3859 }
3859 3860
3860 3861 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3861 3862 // Invokes JVM_OnLoad
3862 3863 void Threads::create_vm_init_libraries() {
3863 3864 extern struct JavaVM_ main_vm;
3864 3865 AgentLibrary* agent;
3865 3866
3866 3867 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3867 3868 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3868 3869
3869 3870 if (on_load_entry != NULL) {
3870 3871 // Invoke the JVM_OnLoad function
3871 3872 JavaThread* thread = JavaThread::current();
3872 3873 ThreadToNativeFromVM ttn(thread);
3873 3874 HandleMark hm(thread);
3874 3875 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3875 3876 if (err != JNI_OK) {
3876 3877 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3877 3878 }
3878 3879 } else {
3879 3880 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3880 3881 }
3881 3882 }
3882 3883 }
3883 3884
3884 3885 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3885 3886 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3886 3887
3887 3888 JavaThread* java_thread = NULL;
3888 3889 // Sequential search for now. Need to do better optimization later.
3889 3890 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3890 3891 oop tobj = thread->threadObj();
3891 3892 if (!thread->is_exiting() &&
3892 3893 tobj != NULL &&
3893 3894 java_tid == java_lang_Thread::thread_id(tobj)) {
3894 3895 java_thread = thread;
3895 3896 break;
3896 3897 }
3897 3898 }
3898 3899 return java_thread;
3899 3900 }
3900 3901
3901 3902
3902 3903 // Last thread running calls java.lang.Shutdown.shutdown()
3903 3904 void JavaThread::invoke_shutdown_hooks() {
3904 3905 HandleMark hm(this);
3905 3906
3906 3907 // We could get here with a pending exception, if so clear it now.
3907 3908 if (this->has_pending_exception()) {
3908 3909 this->clear_pending_exception();
3909 3910 }
3910 3911
3911 3912 EXCEPTION_MARK;
3912 3913 Klass* k =
3913 3914 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3914 3915 THREAD);
3915 3916 if (k != NULL) {
3916 3917 // SystemDictionary::resolve_or_null will return null if there was
3917 3918 // an exception. If we cannot load the Shutdown class, just don't
3918 3919 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3919 3920 // and finalizers (if runFinalizersOnExit is set) won't be run.
3920 3921 // Note that if a shutdown hook was registered or runFinalizersOnExit
3921 3922 // was called, the Shutdown class would have already been loaded
3922 3923 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3923 3924 instanceKlassHandle shutdown_klass (THREAD, k);
3924 3925 JavaValue result(T_VOID);
3925 3926 JavaCalls::call_static(&result,
3926 3927 shutdown_klass,
3927 3928 vmSymbols::shutdown_method_name(),
3928 3929 vmSymbols::void_method_signature(),
3929 3930 THREAD);
3930 3931 }
3931 3932 CLEAR_PENDING_EXCEPTION;
3932 3933 }
3933 3934
3934 3935 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3935 3936 // the program falls off the end of main(). Another VM exit path is through
3936 3937 // vm_exit() when the program calls System.exit() to return a value or when
3937 3938 // there is a serious error in VM. The two shutdown paths are not exactly
3938 3939 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3939 3940 // and VM_Exit op at VM level.
3940 3941 //
3941 3942 // Shutdown sequence:
3942 3943 // + Shutdown native memory tracking if it is on
3943 3944 // + Wait until we are the last non-daemon thread to execute
3944 3945 // <-- every thing is still working at this moment -->
3945 3946 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3946 3947 // shutdown hooks, run finalizers if finalization-on-exit
3947 3948 // + Call before_exit(), prepare for VM exit
3948 3949 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3949 3950 // currently the only user of this mechanism is File.deleteOnExit())
3950 3951 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3951 3952 // post thread end and vm death events to JVMTI,
3952 3953 // stop signal thread
3953 3954 // + Call JavaThread::exit(), it will:
3954 3955 // > release JNI handle blocks, remove stack guard pages
3955 3956 // > remove this thread from Threads list
3956 3957 // <-- no more Java code from this thread after this point -->
3957 3958 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3958 3959 // the compiler threads at safepoint
3959 3960 // <-- do not use anything that could get blocked by Safepoint -->
3960 3961 // + Disable tracing at JNI/JVM barriers
3961 3962 // + Set _vm_exited flag for threads that are still running native code
3962 3963 // + Delete this thread
3963 3964 // + Call exit_globals()
3964 3965 // > deletes tty
3965 3966 // > deletes PerfMemory resources
3966 3967 // + Return to caller
3967 3968
3968 3969 bool Threads::destroy_vm() {
3969 3970 JavaThread* thread = JavaThread::current();
3970 3971
3971 3972 #ifdef ASSERT
3972 3973 _vm_complete = false;
3973 3974 #endif
3974 3975 // Wait until we are the last non-daemon thread to execute
3975 3976 { MutexLocker nu(Threads_lock);
3976 3977 while (Threads::number_of_non_daemon_threads() > 1 )
3977 3978 // This wait should make safepoint checks, wait without a timeout,
3978 3979 // and wait as a suspend-equivalent condition.
3979 3980 //
3980 3981 // Note: If the FlatProfiler is running and this thread is waiting
3981 3982 // for another non-daemon thread to finish, then the FlatProfiler
3982 3983 // is waiting for the external suspend request on this thread to
3983 3984 // complete. wait_for_ext_suspend_completion() will eventually
3984 3985 // timeout, but that takes time. Making this wait a suspend-
3985 3986 // equivalent condition solves that timeout problem.
3986 3987 //
3987 3988 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3988 3989 Mutex::_as_suspend_equivalent_flag);
3989 3990 }
3990 3991
3991 3992 // Hang forever on exit if we are reporting an error.
3992 3993 if (ShowMessageBoxOnError && is_error_reported()) {
3993 3994 os::infinite_sleep();
3994 3995 }
3995 3996 os::wait_for_keypress_at_exit();
3996 3997
3997 3998 if (JDK_Version::is_jdk12x_version()) {
3998 3999 // We are the last thread running, so check if finalizers should be run.
3999 4000 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
4000 4001 HandleMark rm(thread);
4001 4002 Universe::run_finalizers_on_exit();
4002 4003 } else {
4003 4004 // run Java level shutdown hooks
4004 4005 thread->invoke_shutdown_hooks();
4005 4006 }
4006 4007
4007 4008 before_exit(thread);
4008 4009
4009 4010 thread->exit(true);
4010 4011
4011 4012 // Stop VM thread.
4012 4013 {
4013 4014 // 4945125 The vm thread comes to a safepoint during exit.
4014 4015 // GC vm_operations can get caught at the safepoint, and the
4015 4016 // heap is unparseable if they are caught. Grab the Heap_lock
4016 4017 // to prevent this. The GC vm_operations will not be able to
4017 4018 // queue until after the vm thread is dead. After this point,
4018 4019 // we'll never emerge out of the safepoint before the VM exits.
4019 4020
4020 4021 MutexLocker ml(Heap_lock);
4021 4022
4022 4023 VMThread::wait_for_vm_thread_exit();
4023 4024 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4024 4025 VMThread::destroy();
4025 4026 }
4026 4027
4027 4028 // clean up ideal graph printers
4028 4029 #if defined(COMPILER2) && !defined(PRODUCT)
4029 4030 IdealGraphPrinter::clean_up();
4030 4031 #endif
4031 4032
4032 4033 // Now, all Java threads are gone except daemon threads. Daemon threads
4033 4034 // running Java code or in VM are stopped by the Safepoint. However,
4034 4035 // daemon threads executing native code are still running. But they
4035 4036 // will be stopped at native=>Java/VM barriers. Note that we can't
4036 4037 // simply kill or suspend them, as it is inherently deadlock-prone.
4037 4038
4038 4039 #ifndef PRODUCT
4039 4040 // disable function tracing at JNI/JVM barriers
4040 4041 TraceJNICalls = false;
4041 4042 TraceJVMCalls = false;
4042 4043 TraceRuntimeCalls = false;
4043 4044 #endif
4044 4045
4045 4046 VM_Exit::set_vm_exited();
4046 4047
4047 4048 notify_vm_shutdown();
4048 4049
4049 4050 delete thread;
4050 4051
4051 4052 // exit_globals() will delete tty
4052 4053 exit_globals();
4053 4054
4054 4055 return true;
4055 4056 }
4056 4057
4057 4058
4058 4059 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4059 4060 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4060 4061 return is_supported_jni_version(version);
4061 4062 }
4062 4063
4063 4064
4064 4065 jboolean Threads::is_supported_jni_version(jint version) {
4065 4066 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4066 4067 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4067 4068 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4068 4069 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4069 4070 return JNI_FALSE;
4070 4071 }
4071 4072
4072 4073
4073 4074 void Threads::add(JavaThread* p, bool force_daemon) {
4074 4075 // The threads lock must be owned at this point
4075 4076 assert_locked_or_safepoint(Threads_lock);
4076 4077
4077 4078 // See the comment for this method in thread.hpp for its purpose and
4078 4079 // why it is called here.
4079 4080 p->initialize_queues();
4080 4081 p->set_next(_thread_list);
4081 4082 _thread_list = p;
4082 4083 _number_of_threads++;
4083 4084 oop threadObj = p->threadObj();
4084 4085 bool daemon = true;
4085 4086 // Bootstrapping problem: threadObj can be null for initial
4086 4087 // JavaThread (or for threads attached via JNI)
4087 4088 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4088 4089 _number_of_non_daemon_threads++;
4089 4090 daemon = false;
4090 4091 }
4091 4092
4092 4093 ThreadService::add_thread(p, daemon);
4093 4094
4094 4095 // Possible GC point.
4095 4096 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4096 4097 }
4097 4098
4098 4099 void Threads::remove(JavaThread* p) {
4099 4100 // Extra scope needed for Thread_lock, so we can check
4100 4101 // that we do not remove thread without safepoint code notice
4101 4102 { MutexLocker ml(Threads_lock);
4102 4103
4103 4104 assert(includes(p), "p must be present");
4104 4105
4105 4106 JavaThread* current = _thread_list;
4106 4107 JavaThread* prev = NULL;
4107 4108
4108 4109 while (current != p) {
4109 4110 prev = current;
4110 4111 current = current->next();
4111 4112 }
4112 4113
4113 4114 if (prev) {
4114 4115 prev->set_next(current->next());
4115 4116 } else {
4116 4117 _thread_list = p->next();
4117 4118 }
4118 4119 _number_of_threads--;
4119 4120 oop threadObj = p->threadObj();
4120 4121 bool daemon = true;
4121 4122 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4122 4123 _number_of_non_daemon_threads--;
4123 4124 daemon = false;
4124 4125
4125 4126 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4126 4127 // on destroy_vm will wake up.
4127 4128 if (number_of_non_daemon_threads() == 1)
4128 4129 Threads_lock->notify_all();
4129 4130 }
4130 4131 ThreadService::remove_thread(p, daemon);
4131 4132
4132 4133 // Make sure that safepoint code disregard this thread. This is needed since
4133 4134 // the thread might mess around with locks after this point. This can cause it
4134 4135 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4135 4136 // of this thread since it is removed from the queue.
4136 4137 p->set_terminated_value();
4137 4138 } // unlock Threads_lock
4138 4139
4139 4140 // Since Events::log uses a lock, we grab it outside the Threads_lock
4140 4141 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4141 4142 }
4142 4143
4143 4144 // Threads_lock must be held when this is called (or must be called during a safepoint)
4144 4145 bool Threads::includes(JavaThread* p) {
4145 4146 assert(Threads_lock->is_locked(), "sanity check");
4146 4147 ALL_JAVA_THREADS(q) {
4147 4148 if (q == p ) {
4148 4149 return true;
4149 4150 }
4150 4151 }
4151 4152 return false;
4152 4153 }
4153 4154
4154 4155 // Operations on the Threads list for GC. These are not explicitly locked,
4155 4156 // but the garbage collector must provide a safe context for them to run.
4156 4157 // In particular, these things should never be called when the Threads_lock
4157 4158 // is held by some other thread. (Note: the Safepoint abstraction also
4158 4159 // uses the Threads_lock to gurantee this property. It also makes sure that
4159 4160 // all threads gets blocked when exiting or starting).
4160 4161
4161 4162 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4162 4163 ALL_JAVA_THREADS(p) {
4163 4164 p->oops_do(f, cld_f, cf);
4164 4165 }
4165 4166 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4166 4167 }
4167 4168
4168 4169 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4169 4170 // Introduce a mechanism allowing parallel threads to claim threads as
4170 4171 // root groups. Overhead should be small enough to use all the time,
4171 4172 // even in sequential code.
4172 4173 SharedHeap* sh = SharedHeap::heap();
4173 4174 // Cannot yet substitute active_workers for n_par_threads
4174 4175 // because of G1CollectedHeap::verify() use of
4175 4176 // SharedHeap::process_roots(). n_par_threads == 0 will
4176 4177 // turn off parallelism in process_roots while active_workers
4177 4178 // is being used for parallelism elsewhere.
4178 4179 bool is_par = sh->n_par_threads() > 0;
4179 4180 assert(!is_par ||
4180 4181 (SharedHeap::heap()->n_par_threads() ==
4181 4182 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4182 4183 int cp = SharedHeap::heap()->strong_roots_parity();
4183 4184 ALL_JAVA_THREADS(p) {
4184 4185 if (p->claim_oops_do(is_par, cp)) {
4185 4186 p->oops_do(f, cld_f, cf);
4186 4187 }
4187 4188 }
4188 4189 VMThread* vmt = VMThread::vm_thread();
4189 4190 if (vmt->claim_oops_do(is_par, cp)) {
4190 4191 vmt->oops_do(f, cld_f, cf);
4191 4192 }
4192 4193 }
4193 4194
4194 4195 #if INCLUDE_ALL_GCS
4195 4196 // Used by ParallelScavenge
4196 4197 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4197 4198 ALL_JAVA_THREADS(p) {
4198 4199 q->enqueue(new ThreadRootsTask(p));
4199 4200 }
4200 4201 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4201 4202 }
4202 4203
4203 4204 // Used by Parallel Old
4204 4205 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4205 4206 ALL_JAVA_THREADS(p) {
4206 4207 q->enqueue(new ThreadRootsMarkingTask(p));
4207 4208 }
4208 4209 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4209 4210 }
4210 4211 #endif // INCLUDE_ALL_GCS
4211 4212
4212 4213 void Threads::nmethods_do(CodeBlobClosure* cf) {
4213 4214 ALL_JAVA_THREADS(p) {
4214 4215 p->nmethods_do(cf);
4215 4216 }
4216 4217 VMThread::vm_thread()->nmethods_do(cf);
4217 4218 }
4218 4219
4219 4220 void Threads::metadata_do(void f(Metadata*)) {
4220 4221 ALL_JAVA_THREADS(p) {
4221 4222 p->metadata_do(f);
4222 4223 }
4223 4224 }
4224 4225
4225 4226 void Threads::gc_epilogue() {
4226 4227 ALL_JAVA_THREADS(p) {
4227 4228 p->gc_epilogue();
4228 4229 }
4229 4230 }
4230 4231
4231 4232 void Threads::gc_prologue() {
4232 4233 ALL_JAVA_THREADS(p) {
4233 4234 p->gc_prologue();
4234 4235 }
4235 4236 }
4236 4237
4237 4238 void Threads::deoptimized_wrt_marked_nmethods() {
4238 4239 ALL_JAVA_THREADS(p) {
4239 4240 p->deoptimized_wrt_marked_nmethods();
4240 4241 }
4241 4242 }
4242 4243
4243 4244
4244 4245 // Get count Java threads that are waiting to enter the specified monitor.
4245 4246 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4246 4247 address monitor, bool doLock) {
4247 4248 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4248 4249 "must grab Threads_lock or be at safepoint");
4249 4250 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4250 4251
4251 4252 int i = 0;
4252 4253 {
4253 4254 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4254 4255 ALL_JAVA_THREADS(p) {
4255 4256 if (p->is_Compiler_thread()) continue;
4256 4257
4257 4258 address pending = (address)p->current_pending_monitor();
4258 4259 if (pending == monitor) { // found a match
4259 4260 if (i < count) result->append(p); // save the first count matches
4260 4261 i++;
4261 4262 }
4262 4263 }
4263 4264 }
4264 4265 return result;
4265 4266 }
4266 4267
4267 4268
4268 4269 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4269 4270 assert(doLock ||
4270 4271 Threads_lock->owned_by_self() ||
4271 4272 SafepointSynchronize::is_at_safepoint(),
4272 4273 "must grab Threads_lock or be at safepoint");
4273 4274
4274 4275 // NULL owner means not locked so we can skip the search
4275 4276 if (owner == NULL) return NULL;
4276 4277
4277 4278 {
4278 4279 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4279 4280 ALL_JAVA_THREADS(p) {
4280 4281 // first, see if owner is the address of a Java thread
4281 4282 if (owner == (address)p) return p;
4282 4283 }
4283 4284 }
4284 4285 // Cannot assert on lack of success here since this function may be
4285 4286 // used by code that is trying to report useful problem information
4286 4287 // like deadlock detection.
4287 4288 if (UseHeavyMonitors) return NULL;
4288 4289
4289 4290 //
4290 4291 // If we didn't find a matching Java thread and we didn't force use of
4291 4292 // heavyweight monitors, then the owner is the stack address of the
4292 4293 // Lock Word in the owning Java thread's stack.
4293 4294 //
4294 4295 JavaThread* the_owner = NULL;
4295 4296 {
4296 4297 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4297 4298 ALL_JAVA_THREADS(q) {
4298 4299 if (q->is_lock_owned(owner)) {
4299 4300 the_owner = q;
4300 4301 break;
4301 4302 }
4302 4303 }
4303 4304 }
4304 4305 // cannot assert on lack of success here; see above comment
4305 4306 return the_owner;
4306 4307 }
4307 4308
4308 4309 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4309 4310 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4310 4311 char buf[32];
4311 4312 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4312 4313
4313 4314 st->print_cr("Full thread dump %s (%s %s):",
4314 4315 Abstract_VM_Version::vm_name(),
4315 4316 Abstract_VM_Version::vm_release(),
4316 4317 Abstract_VM_Version::vm_info_string()
4317 4318 );
4318 4319 st->cr();
4319 4320
4320 4321 #if INCLUDE_ALL_GCS
4321 4322 // Dump concurrent locks
4322 4323 ConcurrentLocksDump concurrent_locks;
4323 4324 if (print_concurrent_locks) {
4324 4325 concurrent_locks.dump_at_safepoint();
4325 4326 }
4326 4327 #endif // INCLUDE_ALL_GCS
4327 4328
4328 4329 ALL_JAVA_THREADS(p) {
4329 4330 ResourceMark rm;
4330 4331 p->print_on(st);
4331 4332 if (print_stacks) {
4332 4333 if (internal_format) {
4333 4334 p->trace_stack();
4334 4335 } else {
4335 4336 p->print_stack_on(st);
4336 4337 }
4337 4338 }
4338 4339 st->cr();
4339 4340 #if INCLUDE_ALL_GCS
4340 4341 if (print_concurrent_locks) {
4341 4342 concurrent_locks.print_locks_on(p, st);
4342 4343 }
4343 4344 #endif // INCLUDE_ALL_GCS
4344 4345 }
4345 4346
4346 4347 VMThread::vm_thread()->print_on(st);
4347 4348 st->cr();
4348 4349 Universe::heap()->print_gc_threads_on(st);
4349 4350 WatcherThread* wt = WatcherThread::watcher_thread();
4350 4351 if (wt != NULL) {
4351 4352 wt->print_on(st);
4352 4353 st->cr();
4353 4354 }
4354 4355 CompileBroker::print_compiler_threads_on(st);
4355 4356 st->flush();
4356 4357 }
4357 4358
4358 4359 // Threads::print_on_error() is called by fatal error handler. It's possible
4359 4360 // that VM is not at safepoint and/or current thread is inside signal handler.
4360 4361 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4361 4362 // memory (even in resource area), it might deadlock the error handler.
4362 4363 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4363 4364 bool found_current = false;
4364 4365 st->print_cr("Java Threads: ( => current thread )");
4365 4366 ALL_JAVA_THREADS(thread) {
4366 4367 bool is_current = (current == thread);
4367 4368 found_current = found_current || is_current;
4368 4369
4369 4370 st->print("%s", is_current ? "=>" : " ");
4370 4371
4371 4372 st->print(PTR_FORMAT, thread);
4372 4373 st->print(" ");
4373 4374 thread->print_on_error(st, buf, buflen);
4374 4375 st->cr();
4375 4376 }
4376 4377 st->cr();
4377 4378
4378 4379 st->print_cr("Other Threads:");
4379 4380 if (VMThread::vm_thread()) {
4380 4381 bool is_current = (current == VMThread::vm_thread());
4381 4382 found_current = found_current || is_current;
4382 4383 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4383 4384
4384 4385 st->print(PTR_FORMAT, VMThread::vm_thread());
4385 4386 st->print(" ");
4386 4387 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4387 4388 st->cr();
4388 4389 }
4389 4390 WatcherThread* wt = WatcherThread::watcher_thread();
4390 4391 if (wt != NULL) {
4391 4392 bool is_current = (current == wt);
4392 4393 found_current = found_current || is_current;
4393 4394 st->print("%s", is_current ? "=>" : " ");
4394 4395
4395 4396 st->print(PTR_FORMAT, wt);
4396 4397 st->print(" ");
4397 4398 wt->print_on_error(st, buf, buflen);
4398 4399 st->cr();
4399 4400 }
4400 4401 if (!found_current) {
4401 4402 st->cr();
4402 4403 st->print("=>" PTR_FORMAT " (exited) ", current);
4403 4404 current->print_on_error(st, buf, buflen);
4404 4405 st->cr();
4405 4406 }
4406 4407 }
4407 4408
4408 4409 // Internal SpinLock and Mutex
4409 4410 // Based on ParkEvent
4410 4411
4411 4412 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4412 4413 //
4413 4414 // We employ SpinLocks _only for low-contention, fixed-length
4414 4415 // short-duration critical sections where we're concerned
4415 4416 // about native mutex_t or HotSpot Mutex:: latency.
4416 4417 // The mux construct provides a spin-then-block mutual exclusion
4417 4418 // mechanism.
4418 4419 //
4419 4420 // Testing has shown that contention on the ListLock guarding gFreeList
4420 4421 // is common. If we implement ListLock as a simple SpinLock it's common
4421 4422 // for the JVM to devolve to yielding with little progress. This is true
4422 4423 // despite the fact that the critical sections protected by ListLock are
4423 4424 // extremely short.
4424 4425 //
4425 4426 // TODO-FIXME: ListLock should be of type SpinLock.
4426 4427 // We should make this a 1st-class type, integrated into the lock
4427 4428 // hierarchy as leaf-locks. Critically, the SpinLock structure
4428 4429 // should have sufficient padding to avoid false-sharing and excessive
4429 4430 // cache-coherency traffic.
4430 4431
4431 4432
4432 4433 typedef volatile int SpinLockT ;
4433 4434
4434 4435 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4435 4436 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4436 4437 return ; // normal fast-path return
4437 4438 }
4438 4439
4439 4440 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4440 4441 TEVENT (SpinAcquire - ctx) ;
4441 4442 int ctr = 0 ;
4442 4443 int Yields = 0 ;
4443 4444 for (;;) {
4444 4445 while (*adr != 0) {
4445 4446 ++ctr ;
4446 4447 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4447 4448 if (Yields > 5) {
4448 4449 os::naked_short_sleep(1);
4449 4450 } else {
4450 4451 os::NakedYield() ;
4451 4452 ++Yields ;
4452 4453 }
4453 4454 } else {
4454 4455 SpinPause() ;
4455 4456 }
4456 4457 }
4457 4458 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4458 4459 }
4459 4460 }
4460 4461
4461 4462 void Thread::SpinRelease (volatile int * adr) {
4462 4463 assert (*adr != 0, "invariant") ;
4463 4464 OrderAccess::fence() ; // guarantee at least release consistency.
4464 4465 // Roach-motel semantics.
4465 4466 // It's safe if subsequent LDs and STs float "up" into the critical section,
4466 4467 // but prior LDs and STs within the critical section can't be allowed
4467 4468 // to reorder or float past the ST that releases the lock.
4468 4469 *adr = 0 ;
4469 4470 }
4470 4471
4471 4472 // muxAcquire and muxRelease:
4472 4473 //
4473 4474 // * muxAcquire and muxRelease support a single-word lock-word construct.
4474 4475 // The LSB of the word is set IFF the lock is held.
4475 4476 // The remainder of the word points to the head of a singly-linked list
4476 4477 // of threads blocked on the lock.
4477 4478 //
4478 4479 // * The current implementation of muxAcquire-muxRelease uses its own
4479 4480 // dedicated Thread._MuxEvent instance. If we're interested in
4480 4481 // minimizing the peak number of extant ParkEvent instances then
4481 4482 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4482 4483 // as certain invariants were satisfied. Specifically, care would need
4483 4484 // to be taken with regards to consuming unpark() "permits".
4484 4485 // A safe rule of thumb is that a thread would never call muxAcquire()
4485 4486 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4486 4487 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4487 4488 // consume an unpark() permit intended for monitorenter, for instance.
4488 4489 // One way around this would be to widen the restricted-range semaphore
4489 4490 // implemented in park(). Another alternative would be to provide
4490 4491 // multiple instances of the PlatformEvent() for each thread. One
4491 4492 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4492 4493 //
4493 4494 // * Usage:
4494 4495 // -- Only as leaf locks
4495 4496 // -- for short-term locking only as muxAcquire does not perform
4496 4497 // thread state transitions.
4497 4498 //
4498 4499 // Alternatives:
4499 4500 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4500 4501 // but with parking or spin-then-park instead of pure spinning.
4501 4502 // * Use Taura-Oyama-Yonenzawa locks.
4502 4503 // * It's possible to construct a 1-0 lock if we encode the lockword as
4503 4504 // (List,LockByte). Acquire will CAS the full lockword while Release
4504 4505 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4505 4506 // acquiring threads use timers (ParkTimed) to detect and recover from
4506 4507 // the stranding window. Thread/Node structures must be aligned on 256-byte
4507 4508 // boundaries by using placement-new.
4508 4509 // * Augment MCS with advisory back-link fields maintained with CAS().
4509 4510 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4510 4511 // The validity of the backlinks must be ratified before we trust the value.
4511 4512 // If the backlinks are invalid the exiting thread must back-track through the
4512 4513 // the forward links, which are always trustworthy.
4513 4514 // * Add a successor indication. The LockWord is currently encoded as
4514 4515 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4515 4516 // to provide the usual futile-wakeup optimization.
4516 4517 // See RTStt for details.
4517 4518 // * Consider schedctl.sc_nopreempt to cover the critical section.
4518 4519 //
4519 4520
4520 4521
4521 4522 typedef volatile intptr_t MutexT ; // Mux Lock-word
4522 4523 enum MuxBits { LOCKBIT = 1 } ;
4523 4524
4524 4525 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4525 4526 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4526 4527 if (w == 0) return ;
4527 4528 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4528 4529 return ;
4529 4530 }
4530 4531
4531 4532 TEVENT (muxAcquire - Contention) ;
4532 4533 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4533 4534 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4534 4535 for (;;) {
4535 4536 int its = (os::is_MP() ? 100 : 0) + 1 ;
4536 4537
4537 4538 // Optional spin phase: spin-then-park strategy
4538 4539 while (--its >= 0) {
4539 4540 w = *Lock ;
4540 4541 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4541 4542 return ;
4542 4543 }
4543 4544 }
4544 4545
4545 4546 Self->reset() ;
4546 4547 Self->OnList = intptr_t(Lock) ;
4547 4548 // The following fence() isn't _strictly necessary as the subsequent
4548 4549 // CAS() both serializes execution and ratifies the fetched *Lock value.
4549 4550 OrderAccess::fence();
4550 4551 for (;;) {
4551 4552 w = *Lock ;
4552 4553 if ((w & LOCKBIT) == 0) {
4553 4554 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4554 4555 Self->OnList = 0 ; // hygiene - allows stronger asserts
4555 4556 return ;
4556 4557 }
4557 4558 continue ; // Interference -- *Lock changed -- Just retry
4558 4559 }
4559 4560 assert (w & LOCKBIT, "invariant") ;
4560 4561 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4561 4562 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4562 4563 }
4563 4564
4564 4565 while (Self->OnList != 0) {
4565 4566 Self->park() ;
4566 4567 }
4567 4568 }
4568 4569 }
4569 4570
4570 4571 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4571 4572 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4572 4573 if (w == 0) return ;
4573 4574 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4574 4575 return ;
4575 4576 }
4576 4577
4577 4578 TEVENT (muxAcquire - Contention) ;
4578 4579 ParkEvent * ReleaseAfter = NULL ;
4579 4580 if (ev == NULL) {
4580 4581 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4581 4582 }
4582 4583 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4583 4584 for (;;) {
4584 4585 guarantee (ev->OnList == 0, "invariant") ;
4585 4586 int its = (os::is_MP() ? 100 : 0) + 1 ;
4586 4587
4587 4588 // Optional spin phase: spin-then-park strategy
4588 4589 while (--its >= 0) {
4589 4590 w = *Lock ;
4590 4591 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4591 4592 if (ReleaseAfter != NULL) {
4592 4593 ParkEvent::Release (ReleaseAfter) ;
4593 4594 }
4594 4595 return ;
4595 4596 }
4596 4597 }
4597 4598
4598 4599 ev->reset() ;
4599 4600 ev->OnList = intptr_t(Lock) ;
4600 4601 // The following fence() isn't _strictly necessary as the subsequent
4601 4602 // CAS() both serializes execution and ratifies the fetched *Lock value.
4602 4603 OrderAccess::fence();
4603 4604 for (;;) {
4604 4605 w = *Lock ;
4605 4606 if ((w & LOCKBIT) == 0) {
4606 4607 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4607 4608 ev->OnList = 0 ;
4608 4609 // We call ::Release while holding the outer lock, thus
4609 4610 // artificially lengthening the critical section.
4610 4611 // Consider deferring the ::Release() until the subsequent unlock(),
4611 4612 // after we've dropped the outer lock.
4612 4613 if (ReleaseAfter != NULL) {
4613 4614 ParkEvent::Release (ReleaseAfter) ;
4614 4615 }
4615 4616 return ;
4616 4617 }
4617 4618 continue ; // Interference -- *Lock changed -- Just retry
4618 4619 }
4619 4620 assert (w & LOCKBIT, "invariant") ;
4620 4621 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4621 4622 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4622 4623 }
4623 4624
4624 4625 while (ev->OnList != 0) {
4625 4626 ev->park() ;
4626 4627 }
4627 4628 }
4628 4629 }
4629 4630
4630 4631 // Release() must extract a successor from the list and then wake that thread.
4631 4632 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4632 4633 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4633 4634 // Release() would :
4634 4635 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4635 4636 // (B) Extract a successor from the private list "in-hand"
4636 4637 // (C) attempt to CAS() the residual back into *Lock over null.
4637 4638 // If there were any newly arrived threads and the CAS() would fail.
4638 4639 // In that case Release() would detach the RATs, re-merge the list in-hand
4639 4640 // with the RATs and repeat as needed. Alternately, Release() might
4640 4641 // detach and extract a successor, but then pass the residual list to the wakee.
4641 4642 // The wakee would be responsible for reattaching and remerging before it
4642 4643 // competed for the lock.
4643 4644 //
4644 4645 // Both "pop" and DMR are immune from ABA corruption -- there can be
4645 4646 // multiple concurrent pushers, but only one popper or detacher.
4646 4647 // This implementation pops from the head of the list. This is unfair,
4647 4648 // but tends to provide excellent throughput as hot threads remain hot.
4648 4649 // (We wake recently run threads first).
4649 4650
4650 4651 void Thread::muxRelease (volatile intptr_t * Lock) {
4651 4652 for (;;) {
4652 4653 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4653 4654 assert (w & LOCKBIT, "invariant") ;
4654 4655 if (w == LOCKBIT) return ;
4655 4656 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4656 4657 assert (List != NULL, "invariant") ;
4657 4658 assert (List->OnList == intptr_t(Lock), "invariant") ;
4658 4659 ParkEvent * nxt = List->ListNext ;
4659 4660
4660 4661 // The following CAS() releases the lock and pops the head element.
4661 4662 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4662 4663 continue ;
4663 4664 }
4664 4665 List->OnList = 0 ;
4665 4666 OrderAccess::fence() ;
4666 4667 List->unpark () ;
4667 4668 return ;
4668 4669 }
4669 4670 }
4670 4671
4671 4672
4672 4673 void Threads::verify() {
4673 4674 ALL_JAVA_THREADS(p) {
4674 4675 p->verify();
4675 4676 }
4676 4677 VMThread* thread = VMThread::vm_thread();
4677 4678 if (thread != NULL) thread->verify();
4678 4679 }
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