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rev 6875 : 8056240: Investigate increased GC remark time after class unloading changes in CRM Fuse
Reviewed-by: mgerdin, coleenp, bdelsart
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--- old/src/share/vm/runtime/thread.cpp
+++ new/src/share/vm/runtime/thread.cpp
1 1 /*
2 2 * Copyright (c) 1997, 2014, 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());
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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 + _metadata_on_stack_buffer = NULL;
238 +
237 239 // the handle mark links itself to last_handle_mark
238 240 new HandleMark(this);
239 241
240 242 // plain initialization
241 243 debug_only(_owned_locks = NULL;)
242 244 debug_only(_allow_allocation_count = 0;)
243 245 NOT_PRODUCT(_allow_safepoint_count = 0;)
244 246 NOT_PRODUCT(_skip_gcalot = false;)
245 247 _jvmti_env_iteration_count = 0;
246 248 set_allocated_bytes(0);
247 249 _vm_operation_started_count = 0;
248 250 _vm_operation_completed_count = 0;
249 251 _current_pending_monitor = NULL;
250 252 _current_pending_monitor_is_from_java = true;
251 253 _current_waiting_monitor = NULL;
252 254 _num_nested_signal = 0;
253 255 omFreeList = NULL ;
254 256 omFreeCount = 0 ;
255 257 omFreeProvision = 32 ;
256 258 omInUseList = NULL ;
257 259 omInUseCount = 0 ;
258 260
259 261 #ifdef ASSERT
260 262 _visited_for_critical_count = false;
261 263 #endif
262 264
263 265 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
264 266 _suspend_flags = 0;
265 267
266 268 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
267 269 _hashStateX = os::random() ;
268 270 _hashStateY = 842502087 ;
269 271 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
270 272 _hashStateW = 273326509 ;
271 273
272 274 _OnTrap = 0 ;
273 275 _schedctl = NULL ;
274 276 _Stalled = 0 ;
275 277 _TypeTag = 0x2BAD ;
276 278
277 279 // Many of the following fields are effectively final - immutable
278 280 // Note that nascent threads can't use the Native Monitor-Mutex
279 281 // construct until the _MutexEvent is initialized ...
280 282 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
281 283 // we might instead use a stack of ParkEvents that we could provision on-demand.
282 284 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
283 285 // and ::Release()
284 286 _ParkEvent = ParkEvent::Allocate (this) ;
285 287 _SleepEvent = ParkEvent::Allocate (this) ;
286 288 _MutexEvent = ParkEvent::Allocate (this) ;
287 289 _MuxEvent = ParkEvent::Allocate (this) ;
288 290
289 291 #ifdef CHECK_UNHANDLED_OOPS
290 292 if (CheckUnhandledOops) {
291 293 _unhandled_oops = new UnhandledOops(this);
292 294 }
293 295 #endif // CHECK_UNHANDLED_OOPS
294 296 #ifdef ASSERT
295 297 if (UseBiasedLocking) {
296 298 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
297 299 assert(this == _real_malloc_address ||
298 300 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
299 301 "bug in forced alignment of thread objects");
300 302 }
301 303 #endif /* ASSERT */
302 304 }
303 305
304 306 void Thread::initialize_thread_local_storage() {
305 307 // Note: Make sure this method only calls
306 308 // non-blocking operations. Otherwise, it might not work
307 309 // with the thread-startup/safepoint interaction.
308 310
309 311 // During Java thread startup, safepoint code should allow this
310 312 // method to complete because it may need to allocate memory to
311 313 // store information for the new thread.
312 314
313 315 // initialize structure dependent on thread local storage
314 316 ThreadLocalStorage::set_thread(this);
315 317 }
316 318
317 319 void Thread::record_stack_base_and_size() {
318 320 set_stack_base(os::current_stack_base());
319 321 set_stack_size(os::current_stack_size());
320 322 if (is_Java_thread()) {
321 323 ((JavaThread*) this)->set_stack_overflow_limit();
322 324 }
323 325 // CR 7190089: on Solaris, primordial thread's stack is adjusted
324 326 // in initialize_thread(). Without the adjustment, stack size is
325 327 // incorrect if stack is set to unlimited (ulimit -s unlimited).
326 328 // So far, only Solaris has real implementation of initialize_thread().
327 329 //
328 330 // set up any platform-specific state.
329 331 os::initialize_thread(this);
330 332
331 333 #if INCLUDE_NMT
332 334 // record thread's native stack, stack grows downward
333 335 address stack_low_addr = stack_base() - stack_size();
334 336 MemTracker::record_thread_stack(stack_low_addr, stack_size());
335 337 #endif // INCLUDE_NMT
336 338 }
337 339
338 340
339 341 Thread::~Thread() {
340 342 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
341 343 ObjectSynchronizer::omFlush (this) ;
342 344
343 345 EVENT_THREAD_DESTRUCT(this);
344 346
345 347 // stack_base can be NULL if the thread is never started or exited before
346 348 // record_stack_base_and_size called. Although, we would like to ensure
347 349 // that all started threads do call record_stack_base_and_size(), there is
348 350 // not proper way to enforce that.
349 351 #if INCLUDE_NMT
350 352 if (_stack_base != NULL) {
351 353 address low_stack_addr = stack_base() - stack_size();
352 354 MemTracker::release_thread_stack(low_stack_addr, stack_size());
353 355 #ifdef ASSERT
354 356 set_stack_base(NULL);
355 357 #endif
356 358 }
357 359 #endif // INCLUDE_NMT
358 360
359 361 // deallocate data structures
360 362 delete resource_area();
361 363 // since the handle marks are using the handle area, we have to deallocated the root
362 364 // handle mark before deallocating the thread's handle area,
363 365 assert(last_handle_mark() != NULL, "check we have an element");
364 366 delete last_handle_mark();
365 367 assert(last_handle_mark() == NULL, "check we have reached the end");
366 368
367 369 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
368 370 // We NULL out the fields for good hygiene.
369 371 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
370 372 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
371 373 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
372 374 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
373 375
374 376 delete handle_area();
375 377 delete metadata_handles();
376 378
377 379 // osthread() can be NULL, if creation of thread failed.
378 380 if (osthread() != NULL) os::free_thread(osthread());
379 381
380 382 delete _SR_lock;
381 383
382 384 // clear thread local storage if the Thread is deleting itself
383 385 if (this == Thread::current()) {
384 386 ThreadLocalStorage::set_thread(NULL);
385 387 } else {
386 388 // In the case where we're not the current thread, invalidate all the
387 389 // caches in case some code tries to get the current thread or the
388 390 // thread that was destroyed, and gets stale information.
389 391 ThreadLocalStorage::invalidate_all();
390 392 }
391 393 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
392 394 }
393 395
394 396 // NOTE: dummy function for assertion purpose.
395 397 void Thread::run() {
396 398 ShouldNotReachHere();
397 399 }
398 400
399 401 #ifdef ASSERT
400 402 // Private method to check for dangling thread pointer
401 403 void check_for_dangling_thread_pointer(Thread *thread) {
402 404 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
403 405 "possibility of dangling Thread pointer");
404 406 }
405 407 #endif
406 408
407 409
408 410 #ifndef PRODUCT
409 411 // Tracing method for basic thread operations
410 412 void Thread::trace(const char* msg, const Thread* const thread) {
411 413 if (!TraceThreadEvents) return;
412 414 ResourceMark rm;
413 415 ThreadCritical tc;
414 416 const char *name = "non-Java thread";
415 417 int prio = -1;
416 418 if (thread->is_Java_thread()
417 419 && !thread->is_Compiler_thread()) {
418 420 // The Threads_lock must be held to get information about
419 421 // this thread but may not be in some situations when
420 422 // tracing thread events.
421 423 bool release_Threads_lock = false;
422 424 if (!Threads_lock->owned_by_self()) {
423 425 Threads_lock->lock();
424 426 release_Threads_lock = true;
425 427 }
426 428 JavaThread* jt = (JavaThread *)thread;
427 429 name = (char *)jt->get_thread_name();
428 430 oop thread_oop = jt->threadObj();
429 431 if (thread_oop != NULL) {
430 432 prio = java_lang_Thread::priority(thread_oop);
431 433 }
432 434 if (release_Threads_lock) {
433 435 Threads_lock->unlock();
434 436 }
435 437 }
436 438 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
437 439 }
438 440 #endif
439 441
440 442
441 443 ThreadPriority Thread::get_priority(const Thread* const thread) {
442 444 trace("get priority", thread);
443 445 ThreadPriority priority;
444 446 // Can return an error!
445 447 (void)os::get_priority(thread, priority);
446 448 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
447 449 return priority;
448 450 }
449 451
450 452 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
451 453 trace("set priority", thread);
452 454 debug_only(check_for_dangling_thread_pointer(thread);)
453 455 // Can return an error!
454 456 (void)os::set_priority(thread, priority);
455 457 }
456 458
457 459
458 460 void Thread::start(Thread* thread) {
459 461 trace("start", thread);
460 462 // Start is different from resume in that its safety is guaranteed by context or
461 463 // being called from a Java method synchronized on the Thread object.
462 464 if (!DisableStartThread) {
463 465 if (thread->is_Java_thread()) {
464 466 // Initialize the thread state to RUNNABLE before starting this thread.
465 467 // Can not set it after the thread started because we do not know the
466 468 // exact thread state at that time. It could be in MONITOR_WAIT or
467 469 // in SLEEPING or some other state.
468 470 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
469 471 java_lang_Thread::RUNNABLE);
470 472 }
471 473 os::start_thread(thread);
472 474 }
473 475 }
474 476
475 477 // Enqueue a VM_Operation to do the job for us - sometime later
476 478 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
477 479 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
478 480 VMThread::execute(vm_stop);
479 481 }
480 482
481 483
482 484 //
483 485 // Check if an external suspend request has completed (or has been
484 486 // cancelled). Returns true if the thread is externally suspended and
485 487 // false otherwise.
486 488 //
487 489 // The bits parameter returns information about the code path through
488 490 // the routine. Useful for debugging:
489 491 //
490 492 // set in is_ext_suspend_completed():
491 493 // 0x00000001 - routine was entered
492 494 // 0x00000010 - routine return false at end
493 495 // 0x00000100 - thread exited (return false)
494 496 // 0x00000200 - suspend request cancelled (return false)
495 497 // 0x00000400 - thread suspended (return true)
496 498 // 0x00001000 - thread is in a suspend equivalent state (return true)
497 499 // 0x00002000 - thread is native and walkable (return true)
498 500 // 0x00004000 - thread is native_trans and walkable (needed retry)
499 501 //
500 502 // set in wait_for_ext_suspend_completion():
501 503 // 0x00010000 - routine was entered
502 504 // 0x00020000 - suspend request cancelled before loop (return false)
503 505 // 0x00040000 - thread suspended before loop (return true)
504 506 // 0x00080000 - suspend request cancelled in loop (return false)
505 507 // 0x00100000 - thread suspended in loop (return true)
506 508 // 0x00200000 - suspend not completed during retry loop (return false)
507 509 //
508 510
509 511 // Helper class for tracing suspend wait debug bits.
510 512 //
511 513 // 0x00000100 indicates that the target thread exited before it could
512 514 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
513 515 // 0x00080000 each indicate a cancelled suspend request so they don't
514 516 // count as wait failures either.
515 517 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
516 518
517 519 class TraceSuspendDebugBits : public StackObj {
518 520 private:
519 521 JavaThread * jt;
520 522 bool is_wait;
521 523 bool called_by_wait; // meaningful when !is_wait
522 524 uint32_t * bits;
523 525
524 526 public:
525 527 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
526 528 uint32_t *_bits) {
527 529 jt = _jt;
528 530 is_wait = _is_wait;
529 531 called_by_wait = _called_by_wait;
530 532 bits = _bits;
531 533 }
532 534
533 535 ~TraceSuspendDebugBits() {
534 536 if (!is_wait) {
535 537 #if 1
536 538 // By default, don't trace bits for is_ext_suspend_completed() calls.
537 539 // That trace is very chatty.
538 540 return;
539 541 #else
540 542 if (!called_by_wait) {
541 543 // If tracing for is_ext_suspend_completed() is enabled, then only
542 544 // trace calls to it from wait_for_ext_suspend_completion()
543 545 return;
544 546 }
545 547 #endif
546 548 }
547 549
548 550 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
549 551 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
550 552 MutexLocker ml(Threads_lock); // needed for get_thread_name()
551 553 ResourceMark rm;
552 554
553 555 tty->print_cr(
554 556 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
555 557 jt->get_thread_name(), *bits);
556 558
557 559 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
558 560 }
559 561 }
560 562 }
561 563 };
562 564 #undef DEBUG_FALSE_BITS
563 565
564 566
565 567 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
566 568 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
567 569
568 570 bool did_trans_retry = false; // only do thread_in_native_trans retry once
569 571 bool do_trans_retry; // flag to force the retry
570 572
571 573 *bits |= 0x00000001;
572 574
573 575 do {
574 576 do_trans_retry = false;
575 577
576 578 if (is_exiting()) {
577 579 // Thread is in the process of exiting. This is always checked
578 580 // first to reduce the risk of dereferencing a freed JavaThread.
579 581 *bits |= 0x00000100;
580 582 return false;
581 583 }
582 584
583 585 if (!is_external_suspend()) {
584 586 // Suspend request is cancelled. This is always checked before
585 587 // is_ext_suspended() to reduce the risk of a rogue resume
586 588 // confusing the thread that made the suspend request.
587 589 *bits |= 0x00000200;
588 590 return false;
589 591 }
590 592
591 593 if (is_ext_suspended()) {
592 594 // thread is suspended
593 595 *bits |= 0x00000400;
594 596 return true;
595 597 }
596 598
597 599 // Now that we no longer do hard suspends of threads running
598 600 // native code, the target thread can be changing thread state
599 601 // while we are in this routine:
600 602 //
601 603 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
602 604 //
603 605 // We save a copy of the thread state as observed at this moment
604 606 // and make our decision about suspend completeness based on the
605 607 // copy. This closes the race where the thread state is seen as
606 608 // _thread_in_native_trans in the if-thread_blocked check, but is
607 609 // seen as _thread_blocked in if-thread_in_native_trans check.
608 610 JavaThreadState save_state = thread_state();
609 611
610 612 if (save_state == _thread_blocked && is_suspend_equivalent()) {
611 613 // If the thread's state is _thread_blocked and this blocking
612 614 // condition is known to be equivalent to a suspend, then we can
613 615 // consider the thread to be externally suspended. This means that
614 616 // the code that sets _thread_blocked has been modified to do
615 617 // self-suspension if the blocking condition releases. We also
616 618 // used to check for CONDVAR_WAIT here, but that is now covered by
617 619 // the _thread_blocked with self-suspension check.
618 620 //
619 621 // Return true since we wouldn't be here unless there was still an
620 622 // external suspend request.
621 623 *bits |= 0x00001000;
622 624 return true;
623 625 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
624 626 // Threads running native code will self-suspend on native==>VM/Java
625 627 // transitions. If its stack is walkable (should always be the case
626 628 // unless this function is called before the actual java_suspend()
627 629 // call), then the wait is done.
628 630 *bits |= 0x00002000;
629 631 return true;
630 632 } else if (!called_by_wait && !did_trans_retry &&
631 633 save_state == _thread_in_native_trans &&
632 634 frame_anchor()->walkable()) {
633 635 // The thread is transitioning from thread_in_native to another
634 636 // thread state. check_safepoint_and_suspend_for_native_trans()
635 637 // will force the thread to self-suspend. If it hasn't gotten
636 638 // there yet we may have caught the thread in-between the native
637 639 // code check above and the self-suspend. Lucky us. If we were
638 640 // called by wait_for_ext_suspend_completion(), then it
639 641 // will be doing the retries so we don't have to.
640 642 //
641 643 // Since we use the saved thread state in the if-statement above,
642 644 // there is a chance that the thread has already transitioned to
643 645 // _thread_blocked by the time we get here. In that case, we will
644 646 // make a single unnecessary pass through the logic below. This
645 647 // doesn't hurt anything since we still do the trans retry.
646 648
647 649 *bits |= 0x00004000;
648 650
649 651 // Once the thread leaves thread_in_native_trans for another
650 652 // thread state, we break out of this retry loop. We shouldn't
651 653 // need this flag to prevent us from getting back here, but
652 654 // sometimes paranoia is good.
653 655 did_trans_retry = true;
654 656
655 657 // We wait for the thread to transition to a more usable state.
656 658 for (int i = 1; i <= SuspendRetryCount; i++) {
657 659 // We used to do an "os::yield_all(i)" call here with the intention
658 660 // that yielding would increase on each retry. However, the parameter
659 661 // is ignored on Linux which means the yield didn't scale up. Waiting
660 662 // on the SR_lock below provides a much more predictable scale up for
661 663 // the delay. It also provides a simple/direct point to check for any
662 664 // safepoint requests from the VMThread
663 665
664 666 // temporarily drops SR_lock while doing wait with safepoint check
665 667 // (if we're a JavaThread - the WatcherThread can also call this)
666 668 // and increase delay with each retry
667 669 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
668 670
669 671 // check the actual thread state instead of what we saved above
670 672 if (thread_state() != _thread_in_native_trans) {
671 673 // the thread has transitioned to another thread state so
672 674 // try all the checks (except this one) one more time.
673 675 do_trans_retry = true;
674 676 break;
675 677 }
676 678 } // end retry loop
677 679
678 680
679 681 }
680 682 } while (do_trans_retry);
681 683
682 684 *bits |= 0x00000010;
683 685 return false;
684 686 }
685 687
686 688 //
687 689 // Wait for an external suspend request to complete (or be cancelled).
688 690 // Returns true if the thread is externally suspended and false otherwise.
689 691 //
690 692 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
691 693 uint32_t *bits) {
692 694 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
693 695 false /* !called_by_wait */, bits);
694 696
695 697 // local flag copies to minimize SR_lock hold time
696 698 bool is_suspended;
697 699 bool pending;
698 700 uint32_t reset_bits;
699 701
700 702 // set a marker so is_ext_suspend_completed() knows we are the caller
701 703 *bits |= 0x00010000;
702 704
703 705 // We use reset_bits to reinitialize the bits value at the top of
704 706 // each retry loop. This allows the caller to make use of any
705 707 // unused bits for their own marking purposes.
706 708 reset_bits = *bits;
707 709
708 710 {
709 711 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
710 712 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
711 713 delay, bits);
712 714 pending = is_external_suspend();
713 715 }
714 716 // must release SR_lock to allow suspension to complete
715 717
716 718 if (!pending) {
717 719 // A cancelled suspend request is the only false return from
718 720 // is_ext_suspend_completed() that keeps us from entering the
719 721 // retry loop.
720 722 *bits |= 0x00020000;
721 723 return false;
722 724 }
723 725
724 726 if (is_suspended) {
725 727 *bits |= 0x00040000;
726 728 return true;
727 729 }
728 730
729 731 for (int i = 1; i <= retries; i++) {
730 732 *bits = reset_bits; // reinit to only track last retry
731 733
732 734 // We used to do an "os::yield_all(i)" call here with the intention
733 735 // that yielding would increase on each retry. However, the parameter
734 736 // is ignored on Linux which means the yield didn't scale up. Waiting
735 737 // on the SR_lock below provides a much more predictable scale up for
736 738 // the delay. It also provides a simple/direct point to check for any
737 739 // safepoint requests from the VMThread
738 740
739 741 {
740 742 MutexLocker ml(SR_lock());
741 743 // wait with safepoint check (if we're a JavaThread - the WatcherThread
742 744 // can also call this) and increase delay with each retry
743 745 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
744 746
745 747 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
746 748 delay, bits);
747 749
748 750 // It is possible for the external suspend request to be cancelled
749 751 // (by a resume) before the actual suspend operation is completed.
750 752 // Refresh our local copy to see if we still need to wait.
751 753 pending = is_external_suspend();
752 754 }
753 755
754 756 if (!pending) {
755 757 // A cancelled suspend request is the only false return from
756 758 // is_ext_suspend_completed() that keeps us from staying in the
757 759 // retry loop.
758 760 *bits |= 0x00080000;
759 761 return false;
760 762 }
761 763
762 764 if (is_suspended) {
763 765 *bits |= 0x00100000;
764 766 return true;
765 767 }
766 768 } // end retry loop
767 769
768 770 // thread did not suspend after all our retries
769 771 *bits |= 0x00200000;
770 772 return false;
771 773 }
772 774
773 775 #ifndef PRODUCT
774 776 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
775 777
776 778 // This should not need to be atomic as the only way for simultaneous
777 779 // updates is via interrupts. Even then this should be rare or non-existant
778 780 // and we don't care that much anyway.
779 781
780 782 int index = _jmp_ring_index;
781 783 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
782 784 _jmp_ring[index]._target = (intptr_t) target;
783 785 _jmp_ring[index]._instruction = (intptr_t) instr;
784 786 _jmp_ring[index]._file = file;
785 787 _jmp_ring[index]._line = line;
786 788 }
787 789 #endif /* PRODUCT */
788 790
789 791 // Called by flat profiler
790 792 // Callers have already called wait_for_ext_suspend_completion
791 793 // The assertion for that is currently too complex to put here:
792 794 bool JavaThread::profile_last_Java_frame(frame* _fr) {
793 795 bool gotframe = false;
794 796 // self suspension saves needed state.
795 797 if (has_last_Java_frame() && _anchor.walkable()) {
796 798 *_fr = pd_last_frame();
797 799 gotframe = true;
798 800 }
799 801 return gotframe;
800 802 }
801 803
802 804 void Thread::interrupt(Thread* thread) {
803 805 trace("interrupt", thread);
804 806 debug_only(check_for_dangling_thread_pointer(thread);)
805 807 os::interrupt(thread);
806 808 }
807 809
808 810 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
809 811 trace("is_interrupted", thread);
810 812 debug_only(check_for_dangling_thread_pointer(thread);)
811 813 // Note: If clear_interrupted==false, this simply fetches and
812 814 // returns the value of the field osthread()->interrupted().
813 815 return os::is_interrupted(thread, clear_interrupted);
814 816 }
815 817
816 818
817 819 // GC Support
818 820 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
819 821 jint thread_parity = _oops_do_parity;
820 822 if (thread_parity != strong_roots_parity) {
821 823 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
822 824 if (res == thread_parity) {
823 825 return true;
824 826 } else {
825 827 guarantee(res == strong_roots_parity, "Or else what?");
826 828 assert(SharedHeap::heap()->workers()->active_workers() > 0,
827 829 "Should only fail when parallel.");
828 830 return false;
829 831 }
830 832 }
831 833 assert(SharedHeap::heap()->workers()->active_workers() > 0,
832 834 "Should only fail when parallel.");
833 835 return false;
834 836 }
835 837
836 838 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
837 839 active_handles()->oops_do(f);
838 840 // Do oop for ThreadShadow
839 841 f->do_oop((oop*)&_pending_exception);
840 842 handle_area()->oops_do(f);
841 843 }
842 844
843 845 void Thread::nmethods_do(CodeBlobClosure* cf) {
844 846 // no nmethods in a generic thread...
845 847 }
846 848
847 849 void Thread::metadata_do(void f(Metadata*)) {
848 850 if (metadata_handles() != NULL) {
849 851 for (int i = 0; i< metadata_handles()->length(); i++) {
850 852 f(metadata_handles()->at(i));
851 853 }
852 854 }
853 855 }
854 856
855 857 void Thread::print_on(outputStream* st) const {
856 858 // get_priority assumes osthread initialized
857 859 if (osthread() != NULL) {
858 860 int os_prio;
859 861 if (os::get_native_priority(this, &os_prio) == OS_OK) {
860 862 st->print("os_prio=%d ", os_prio);
861 863 }
862 864 st->print("tid=" INTPTR_FORMAT " ", this);
863 865 ext().print_on(st);
864 866 osthread()->print_on(st);
865 867 }
866 868 debug_only(if (WizardMode) print_owned_locks_on(st);)
867 869 }
868 870
869 871 // Thread::print_on_error() is called by fatal error handler. Don't use
870 872 // any lock or allocate memory.
871 873 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
872 874 if (is_VM_thread()) st->print("VMThread");
873 875 else if (is_Compiler_thread()) st->print("CompilerThread");
874 876 else if (is_Java_thread()) st->print("JavaThread");
875 877 else if (is_GC_task_thread()) st->print("GCTaskThread");
876 878 else if (is_Watcher_thread()) st->print("WatcherThread");
877 879 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
878 880 else st->print("Thread");
879 881
880 882 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
881 883 _stack_base - _stack_size, _stack_base);
882 884
883 885 if (osthread()) {
884 886 st->print(" [id=%d]", osthread()->thread_id());
885 887 }
886 888 }
887 889
888 890 #ifdef ASSERT
889 891 void Thread::print_owned_locks_on(outputStream* st) const {
890 892 Monitor *cur = _owned_locks;
891 893 if (cur == NULL) {
892 894 st->print(" (no locks) ");
893 895 } else {
894 896 st->print_cr(" Locks owned:");
895 897 while(cur) {
896 898 cur->print_on(st);
897 899 cur = cur->next();
898 900 }
899 901 }
900 902 }
901 903
902 904 static int ref_use_count = 0;
903 905
904 906 bool Thread::owns_locks_but_compiled_lock() const {
905 907 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
906 908 if (cur != Compile_lock) return true;
907 909 }
908 910 return false;
909 911 }
910 912
911 913
912 914 #endif
913 915
914 916 #ifndef PRODUCT
915 917
916 918 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
917 919 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
918 920 // no threads which allow_vm_block's are held
919 921 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
920 922 // Check if current thread is allowed to block at a safepoint
921 923 if (!(_allow_safepoint_count == 0))
922 924 fatal("Possible safepoint reached by thread that does not allow it");
923 925 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
924 926 fatal("LEAF method calling lock?");
925 927 }
926 928
927 929 #ifdef ASSERT
928 930 if (potential_vm_operation && is_Java_thread()
929 931 && !Universe::is_bootstrapping()) {
930 932 // Make sure we do not hold any locks that the VM thread also uses.
931 933 // This could potentially lead to deadlocks
932 934 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
933 935 // Threads_lock is special, since the safepoint synchronization will not start before this is
934 936 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
935 937 // since it is used to transfer control between JavaThreads and the VMThread
936 938 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
937 939 if ( (cur->allow_vm_block() &&
938 940 cur != Threads_lock &&
939 941 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
940 942 cur != VMOperationRequest_lock &&
941 943 cur != VMOperationQueue_lock) ||
942 944 cur->rank() == Mutex::special) {
943 945 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name()));
944 946 }
945 947 }
946 948 }
947 949
948 950 if (GCALotAtAllSafepoints) {
949 951 // We could enter a safepoint here and thus have a gc
950 952 InterfaceSupport::check_gc_alot();
951 953 }
952 954 #endif
953 955 }
954 956 #endif
955 957
956 958 bool Thread::is_in_stack(address adr) const {
957 959 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
958 960 address end = os::current_stack_pointer();
959 961 // Allow non Java threads to call this without stack_base
960 962 if (_stack_base == NULL) return true;
961 963 if (stack_base() >= adr && adr >= end) return true;
962 964
963 965 return false;
964 966 }
965 967
966 968
967 969 bool Thread::is_in_usable_stack(address adr) const {
968 970 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0;
969 971 size_t usable_stack_size = _stack_size - stack_guard_size;
970 972
971 973 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
972 974 }
973 975
974 976
975 977 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
976 978 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
977 979 // used for compilation in the future. If that change is made, the need for these methods
978 980 // should be revisited, and they should be removed if possible.
979 981
980 982 bool Thread::is_lock_owned(address adr) const {
981 983 return on_local_stack(adr);
982 984 }
983 985
984 986 bool Thread::set_as_starting_thread() {
985 987 // NOTE: this must be called inside the main thread.
986 988 return os::create_main_thread((JavaThread*)this);
987 989 }
988 990
989 991 static void initialize_class(Symbol* class_name, TRAPS) {
990 992 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
991 993 InstanceKlass::cast(klass)->initialize(CHECK);
992 994 }
993 995
994 996
995 997 // Creates the initial ThreadGroup
996 998 static Handle create_initial_thread_group(TRAPS) {
997 999 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
998 1000 instanceKlassHandle klass (THREAD, k);
999 1001
1000 1002 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
1001 1003 {
1002 1004 JavaValue result(T_VOID);
1003 1005 JavaCalls::call_special(&result,
1004 1006 system_instance,
1005 1007 klass,
1006 1008 vmSymbols::object_initializer_name(),
1007 1009 vmSymbols::void_method_signature(),
1008 1010 CHECK_NH);
1009 1011 }
1010 1012 Universe::set_system_thread_group(system_instance());
1011 1013
1012 1014 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
1013 1015 {
1014 1016 JavaValue result(T_VOID);
1015 1017 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
1016 1018 JavaCalls::call_special(&result,
1017 1019 main_instance,
1018 1020 klass,
1019 1021 vmSymbols::object_initializer_name(),
1020 1022 vmSymbols::threadgroup_string_void_signature(),
1021 1023 system_instance,
1022 1024 string,
1023 1025 CHECK_NH);
1024 1026 }
1025 1027 return main_instance;
1026 1028 }
1027 1029
1028 1030 // Creates the initial Thread
1029 1031 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
1030 1032 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
1031 1033 instanceKlassHandle klass (THREAD, k);
1032 1034 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
1033 1035
1034 1036 java_lang_Thread::set_thread(thread_oop(), thread);
1035 1037 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1036 1038 thread->set_threadObj(thread_oop());
1037 1039
1038 1040 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
1039 1041
1040 1042 JavaValue result(T_VOID);
1041 1043 JavaCalls::call_special(&result, thread_oop,
1042 1044 klass,
1043 1045 vmSymbols::object_initializer_name(),
1044 1046 vmSymbols::threadgroup_string_void_signature(),
1045 1047 thread_group,
1046 1048 string,
1047 1049 CHECK_NULL);
1048 1050 return thread_oop();
1049 1051 }
1050 1052
1051 1053 static void call_initializeSystemClass(TRAPS) {
1052 1054 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1053 1055 instanceKlassHandle klass (THREAD, k);
1054 1056
1055 1057 JavaValue result(T_VOID);
1056 1058 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
1057 1059 vmSymbols::void_method_signature(), CHECK);
1058 1060 }
1059 1061
1060 1062 char java_runtime_name[128] = "";
1061 1063 char java_runtime_version[128] = "";
1062 1064
1063 1065 // extract the JRE name from sun.misc.Version.java_runtime_name
1064 1066 static const char* get_java_runtime_name(TRAPS) {
1065 1067 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1066 1068 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1067 1069 fieldDescriptor fd;
1068 1070 bool found = k != NULL &&
1069 1071 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
1070 1072 vmSymbols::string_signature(), &fd);
1071 1073 if (found) {
1072 1074 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1073 1075 if (name_oop == NULL)
1074 1076 return NULL;
1075 1077 const char* name = java_lang_String::as_utf8_string(name_oop,
1076 1078 java_runtime_name,
1077 1079 sizeof(java_runtime_name));
1078 1080 return name;
1079 1081 } else {
1080 1082 return NULL;
1081 1083 }
1082 1084 }
1083 1085
1084 1086 // extract the JRE version from sun.misc.Version.java_runtime_version
1085 1087 static const char* get_java_runtime_version(TRAPS) {
1086 1088 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(),
1087 1089 Handle(), Handle(), CHECK_AND_CLEAR_NULL);
1088 1090 fieldDescriptor fd;
1089 1091 bool found = k != NULL &&
1090 1092 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
1091 1093 vmSymbols::string_signature(), &fd);
1092 1094 if (found) {
1093 1095 oop name_oop = k->java_mirror()->obj_field(fd.offset());
1094 1096 if (name_oop == NULL)
1095 1097 return NULL;
1096 1098 const char* name = java_lang_String::as_utf8_string(name_oop,
1097 1099 java_runtime_version,
1098 1100 sizeof(java_runtime_version));
1099 1101 return name;
1100 1102 } else {
1101 1103 return NULL;
1102 1104 }
1103 1105 }
1104 1106
1105 1107 // General purpose hook into Java code, run once when the VM is initialized.
1106 1108 // The Java library method itself may be changed independently from the VM.
1107 1109 static void call_postVMInitHook(TRAPS) {
1108 1110 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD);
1109 1111 instanceKlassHandle klass (THREAD, k);
1110 1112 if (klass.not_null()) {
1111 1113 JavaValue result(T_VOID);
1112 1114 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
1113 1115 vmSymbols::void_method_signature(),
1114 1116 CHECK);
1115 1117 }
1116 1118 }
1117 1119
1118 1120 static void reset_vm_info_property(TRAPS) {
1119 1121 // the vm info string
1120 1122 ResourceMark rm(THREAD);
1121 1123 const char *vm_info = VM_Version::vm_info_string();
1122 1124
1123 1125 // java.lang.System class
1124 1126 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
1125 1127 instanceKlassHandle klass (THREAD, k);
1126 1128
1127 1129 // setProperty arguments
1128 1130 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
1129 1131 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
1130 1132
1131 1133 // return value
1132 1134 JavaValue r(T_OBJECT);
1133 1135
1134 1136 // public static String setProperty(String key, String value);
1135 1137 JavaCalls::call_static(&r,
1136 1138 klass,
1137 1139 vmSymbols::setProperty_name(),
1138 1140 vmSymbols::string_string_string_signature(),
1139 1141 key_str,
1140 1142 value_str,
1141 1143 CHECK);
1142 1144 }
1143 1145
1144 1146
1145 1147 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1146 1148 assert(thread_group.not_null(), "thread group should be specified");
1147 1149 assert(threadObj() == NULL, "should only create Java thread object once");
1148 1150
1149 1151 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1150 1152 instanceKlassHandle klass (THREAD, k);
1151 1153 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1152 1154
1153 1155 java_lang_Thread::set_thread(thread_oop(), this);
1154 1156 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1155 1157 set_threadObj(thread_oop());
1156 1158
1157 1159 JavaValue result(T_VOID);
1158 1160 if (thread_name != NULL) {
1159 1161 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1160 1162 // Thread gets assigned specified name and null target
1161 1163 JavaCalls::call_special(&result,
1162 1164 thread_oop,
1163 1165 klass,
1164 1166 vmSymbols::object_initializer_name(),
1165 1167 vmSymbols::threadgroup_string_void_signature(),
1166 1168 thread_group, // Argument 1
1167 1169 name, // Argument 2
1168 1170 THREAD);
1169 1171 } else {
1170 1172 // Thread gets assigned name "Thread-nnn" and null target
1171 1173 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1172 1174 JavaCalls::call_special(&result,
1173 1175 thread_oop,
1174 1176 klass,
1175 1177 vmSymbols::object_initializer_name(),
1176 1178 vmSymbols::threadgroup_runnable_void_signature(),
1177 1179 thread_group, // Argument 1
1178 1180 Handle(), // Argument 2
1179 1181 THREAD);
1180 1182 }
1181 1183
1182 1184
1183 1185 if (daemon) {
1184 1186 java_lang_Thread::set_daemon(thread_oop());
1185 1187 }
1186 1188
1187 1189 if (HAS_PENDING_EXCEPTION) {
1188 1190 return;
1189 1191 }
1190 1192
1191 1193 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1192 1194 Handle threadObj(this, this->threadObj());
1193 1195
1194 1196 JavaCalls::call_special(&result,
1195 1197 thread_group,
1196 1198 group,
1197 1199 vmSymbols::add_method_name(),
1198 1200 vmSymbols::thread_void_signature(),
1199 1201 threadObj, // Arg 1
1200 1202 THREAD);
1201 1203
1202 1204
1203 1205 }
1204 1206
1205 1207 // NamedThread -- non-JavaThread subclasses with multiple
1206 1208 // uniquely named instances should derive from this.
1207 1209 NamedThread::NamedThread() : Thread() {
1208 1210 _name = NULL;
1209 1211 _processed_thread = NULL;
1210 1212 }
1211 1213
1212 1214 NamedThread::~NamedThread() {
1213 1215 if (_name != NULL) {
1214 1216 FREE_C_HEAP_ARRAY(char, _name, mtThread);
1215 1217 _name = NULL;
1216 1218 }
1217 1219 }
1218 1220
1219 1221 void NamedThread::set_name(const char* format, ...) {
1220 1222 guarantee(_name == NULL, "Only get to set name once.");
1221 1223 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
1222 1224 guarantee(_name != NULL, "alloc failure");
1223 1225 va_list ap;
1224 1226 va_start(ap, format);
1225 1227 jio_vsnprintf(_name, max_name_len, format, ap);
1226 1228 va_end(ap);
1227 1229 }
1228 1230
1229 1231 // ======= WatcherThread ========
1230 1232
1231 1233 // The watcher thread exists to simulate timer interrupts. It should
1232 1234 // be replaced by an abstraction over whatever native support for
1233 1235 // timer interrupts exists on the platform.
1234 1236
1235 1237 WatcherThread* WatcherThread::_watcher_thread = NULL;
1236 1238 bool WatcherThread::_startable = false;
1237 1239 volatile bool WatcherThread::_should_terminate = false;
1238 1240
1239 1241 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) {
1240 1242 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1241 1243 if (os::create_thread(this, os::watcher_thread)) {
1242 1244 _watcher_thread = this;
1243 1245
1244 1246 // Set the watcher thread to the highest OS priority which should not be
1245 1247 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1246 1248 // is created. The only normal thread using this priority is the reference
1247 1249 // handler thread, which runs for very short intervals only.
1248 1250 // If the VMThread's priority is not lower than the WatcherThread profiling
1249 1251 // will be inaccurate.
1250 1252 os::set_priority(this, MaxPriority);
1251 1253 if (!DisableStartThread) {
1252 1254 os::start_thread(this);
1253 1255 }
1254 1256 }
1255 1257 }
1256 1258
1257 1259 int WatcherThread::sleep() const {
1258 1260 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1259 1261
1260 1262 // remaining will be zero if there are no tasks,
1261 1263 // causing the WatcherThread to sleep until a task is
1262 1264 // enrolled
1263 1265 int remaining = PeriodicTask::time_to_wait();
1264 1266 int time_slept = 0;
1265 1267
1266 1268 // we expect this to timeout - we only ever get unparked when
1267 1269 // we should terminate or when a new task has been enrolled
1268 1270 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1269 1271
1270 1272 jlong time_before_loop = os::javaTimeNanos();
1271 1273
1272 1274 for (;;) {
1273 1275 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining);
1274 1276 jlong now = os::javaTimeNanos();
1275 1277
1276 1278 if (remaining == 0) {
1277 1279 // if we didn't have any tasks we could have waited for a long time
1278 1280 // consider the time_slept zero and reset time_before_loop
1279 1281 time_slept = 0;
1280 1282 time_before_loop = now;
1281 1283 } else {
1282 1284 // need to recalulate since we might have new tasks in _tasks
1283 1285 time_slept = (int) ((now - time_before_loop) / 1000000);
1284 1286 }
1285 1287
1286 1288 // Change to task list or spurious wakeup of some kind
1287 1289 if (timedout || _should_terminate) {
1288 1290 break;
1289 1291 }
1290 1292
1291 1293 remaining = PeriodicTask::time_to_wait();
1292 1294 if (remaining == 0) {
1293 1295 // Last task was just disenrolled so loop around and wait until
1294 1296 // another task gets enrolled
1295 1297 continue;
1296 1298 }
1297 1299
1298 1300 remaining -= time_slept;
1299 1301 if (remaining <= 0)
1300 1302 break;
1301 1303 }
1302 1304
1303 1305 return time_slept;
1304 1306 }
1305 1307
1306 1308 void WatcherThread::run() {
1307 1309 assert(this == watcher_thread(), "just checking");
1308 1310
1309 1311 this->record_stack_base_and_size();
1310 1312 this->initialize_thread_local_storage();
1311 1313 this->set_active_handles(JNIHandleBlock::allocate_block());
1312 1314 while(!_should_terminate) {
1313 1315 assert(watcher_thread() == Thread::current(), "thread consistency check");
1314 1316 assert(watcher_thread() == this, "thread consistency check");
1315 1317
1316 1318 // Calculate how long it'll be until the next PeriodicTask work
1317 1319 // should be done, and sleep that amount of time.
1318 1320 int time_waited = sleep();
1319 1321
1320 1322 if (is_error_reported()) {
1321 1323 // A fatal error has happened, the error handler(VMError::report_and_die)
1322 1324 // should abort JVM after creating an error log file. However in some
1323 1325 // rare cases, the error handler itself might deadlock. Here we try to
1324 1326 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1325 1327 //
1326 1328 // This code is in WatcherThread because WatcherThread wakes up
1327 1329 // periodically so the fatal error handler doesn't need to do anything;
1328 1330 // also because the WatcherThread is less likely to crash than other
1329 1331 // threads.
1330 1332
1331 1333 for (;;) {
1332 1334 if (!ShowMessageBoxOnError
1333 1335 && (OnError == NULL || OnError[0] == '\0')
1334 1336 && Arguments::abort_hook() == NULL) {
1335 1337 os::sleep(this, 2 * 60 * 1000, false);
1336 1338 fdStream err(defaultStream::output_fd());
1337 1339 err.print_raw_cr("# [ timer expired, abort... ]");
1338 1340 // skip atexit/vm_exit/vm_abort hooks
1339 1341 os::die();
1340 1342 }
1341 1343
1342 1344 // Wake up 5 seconds later, the fatal handler may reset OnError or
1343 1345 // ShowMessageBoxOnError when it is ready to abort.
1344 1346 os::sleep(this, 5 * 1000, false);
1345 1347 }
1346 1348 }
1347 1349
1348 1350 PeriodicTask::real_time_tick(time_waited);
1349 1351 }
1350 1352
1351 1353 // Signal that it is terminated
1352 1354 {
1353 1355 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1354 1356 _watcher_thread = NULL;
1355 1357 Terminator_lock->notify();
1356 1358 }
1357 1359
1358 1360 // Thread destructor usually does this..
1359 1361 ThreadLocalStorage::set_thread(NULL);
1360 1362 }
1361 1363
1362 1364 void WatcherThread::start() {
1363 1365 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1364 1366
1365 1367 if (watcher_thread() == NULL && _startable) {
1366 1368 _should_terminate = false;
1367 1369 // Create the single instance of WatcherThread
1368 1370 new WatcherThread();
1369 1371 }
1370 1372 }
1371 1373
1372 1374 void WatcherThread::make_startable() {
1373 1375 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
1374 1376 _startable = true;
1375 1377 }
1376 1378
1377 1379 void WatcherThread::stop() {
1378 1380 {
1379 1381 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1380 1382 _should_terminate = true;
1381 1383 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1382 1384
1383 1385 WatcherThread* watcher = watcher_thread();
1384 1386 if (watcher != NULL)
1385 1387 watcher->unpark();
1386 1388 }
1387 1389
1388 1390 // it is ok to take late safepoints here, if needed
1389 1391 MutexLocker mu(Terminator_lock);
1390 1392
1391 1393 while(watcher_thread() != NULL) {
1392 1394 // This wait should make safepoint checks, wait without a timeout,
1393 1395 // and wait as a suspend-equivalent condition.
1394 1396 //
1395 1397 // Note: If the FlatProfiler is running, then this thread is waiting
1396 1398 // for the WatcherThread to terminate and the WatcherThread, via the
1397 1399 // FlatProfiler task, is waiting for the external suspend request on
1398 1400 // this thread to complete. wait_for_ext_suspend_completion() will
1399 1401 // eventually timeout, but that takes time. Making this wait a
1400 1402 // suspend-equivalent condition solves that timeout problem.
1401 1403 //
1402 1404 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1403 1405 Mutex::_as_suspend_equivalent_flag);
1404 1406 }
1405 1407 }
1406 1408
1407 1409 void WatcherThread::unpark() {
1408 1410 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
1409 1411 PeriodicTask_lock->notify();
1410 1412 }
1411 1413
1412 1414 void WatcherThread::print_on(outputStream* st) const {
1413 1415 st->print("\"%s\" ", name());
1414 1416 Thread::print_on(st);
1415 1417 st->cr();
1416 1418 }
1417 1419
1418 1420 // ======= JavaThread ========
1419 1421
1420 1422 // A JavaThread is a normal Java thread
1421 1423
1422 1424 void JavaThread::initialize() {
1423 1425 // Initialize fields
1424 1426
1425 1427 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids)
1426 1428 set_claimed_par_id(UINT_MAX);
1427 1429
1428 1430 set_saved_exception_pc(NULL);
1429 1431 set_threadObj(NULL);
1430 1432 _anchor.clear();
1431 1433 set_entry_point(NULL);
1432 1434 set_jni_functions(jni_functions());
1433 1435 set_callee_target(NULL);
1434 1436 set_vm_result(NULL);
1435 1437 set_vm_result_2(NULL);
1436 1438 set_vframe_array_head(NULL);
1437 1439 set_vframe_array_last(NULL);
1438 1440 set_deferred_locals(NULL);
1439 1441 set_deopt_mark(NULL);
1440 1442 set_deopt_nmethod(NULL);
1441 1443 clear_must_deopt_id();
1442 1444 set_monitor_chunks(NULL);
1443 1445 set_next(NULL);
1444 1446 set_thread_state(_thread_new);
1445 1447 _terminated = _not_terminated;
1446 1448 _privileged_stack_top = NULL;
1447 1449 _array_for_gc = NULL;
1448 1450 _suspend_equivalent = false;
1449 1451 _in_deopt_handler = 0;
1450 1452 _doing_unsafe_access = false;
1451 1453 _stack_guard_state = stack_guard_unused;
1452 1454 (void)const_cast<oop&>(_exception_oop = NULL);
1453 1455 _exception_pc = 0;
1454 1456 _exception_handler_pc = 0;
1455 1457 _is_method_handle_return = 0;
1456 1458 _jvmti_thread_state= NULL;
1457 1459 _should_post_on_exceptions_flag = JNI_FALSE;
1458 1460 _jvmti_get_loaded_classes_closure = NULL;
1459 1461 _interp_only_mode = 0;
1460 1462 _special_runtime_exit_condition = _no_async_condition;
1461 1463 _pending_async_exception = NULL;
1462 1464 _thread_stat = NULL;
1463 1465 _thread_stat = new ThreadStatistics();
1464 1466 _blocked_on_compilation = false;
1465 1467 _jni_active_critical = 0;
1466 1468 _do_not_unlock_if_synchronized = false;
1467 1469 _cached_monitor_info = NULL;
1468 1470 _parker = Parker::Allocate(this) ;
1469 1471
1470 1472 #ifndef PRODUCT
1471 1473 _jmp_ring_index = 0;
1472 1474 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1473 1475 record_jump(NULL, NULL, NULL, 0);
1474 1476 }
1475 1477 #endif /* PRODUCT */
1476 1478
1477 1479 set_thread_profiler(NULL);
1478 1480 if (FlatProfiler::is_active()) {
1479 1481 // This is where we would decide to either give each thread it's own profiler
1480 1482 // or use one global one from FlatProfiler,
1481 1483 // or up to some count of the number of profiled threads, etc.
1482 1484 ThreadProfiler* pp = new ThreadProfiler();
1483 1485 pp->engage();
1484 1486 set_thread_profiler(pp);
1485 1487 }
1486 1488
1487 1489 // Setup safepoint state info for this thread
1488 1490 ThreadSafepointState::create(this);
1489 1491
1490 1492 debug_only(_java_call_counter = 0);
1491 1493
1492 1494 // JVMTI PopFrame support
1493 1495 _popframe_condition = popframe_inactive;
1494 1496 _popframe_preserved_args = NULL;
1495 1497 _popframe_preserved_args_size = 0;
1496 1498
1497 1499 pd_initialize();
1498 1500 }
1499 1501
1500 1502 #if INCLUDE_ALL_GCS
1501 1503 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1502 1504 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1503 1505 #endif // INCLUDE_ALL_GCS
1504 1506
1505 1507 JavaThread::JavaThread(bool is_attaching_via_jni) :
1506 1508 Thread()
1507 1509 #if INCLUDE_ALL_GCS
1508 1510 , _satb_mark_queue(&_satb_mark_queue_set),
1509 1511 _dirty_card_queue(&_dirty_card_queue_set)
1510 1512 #endif // INCLUDE_ALL_GCS
1511 1513 {
1512 1514 initialize();
1513 1515 if (is_attaching_via_jni) {
1514 1516 _jni_attach_state = _attaching_via_jni;
1515 1517 } else {
1516 1518 _jni_attach_state = _not_attaching_via_jni;
1517 1519 }
1518 1520 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
1519 1521 }
1520 1522
1521 1523 bool JavaThread::reguard_stack(address cur_sp) {
1522 1524 if (_stack_guard_state != stack_guard_yellow_disabled) {
1523 1525 return true; // Stack already guarded or guard pages not needed.
1524 1526 }
1525 1527
1526 1528 if (register_stack_overflow()) {
1527 1529 // For those architectures which have separate register and
1528 1530 // memory stacks, we must check the register stack to see if
1529 1531 // it has overflowed.
1530 1532 return false;
1531 1533 }
1532 1534
1533 1535 // Java code never executes within the yellow zone: the latter is only
1534 1536 // there to provoke an exception during stack banging. If java code
1535 1537 // is executing there, either StackShadowPages should be larger, or
1536 1538 // some exception code in c1, c2 or the interpreter isn't unwinding
1537 1539 // when it should.
1538 1540 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1539 1541
1540 1542 enable_stack_yellow_zone();
1541 1543 return true;
1542 1544 }
1543 1545
1544 1546 bool JavaThread::reguard_stack(void) {
1545 1547 return reguard_stack(os::current_stack_pointer());
1546 1548 }
1547 1549
1548 1550
1549 1551 void JavaThread::block_if_vm_exited() {
1550 1552 if (_terminated == _vm_exited) {
1551 1553 // _vm_exited is set at safepoint, and Threads_lock is never released
1552 1554 // we will block here forever
1553 1555 Threads_lock->lock_without_safepoint_check();
1554 1556 ShouldNotReachHere();
1555 1557 }
1556 1558 }
1557 1559
1558 1560
1559 1561 // Remove this ifdef when C1 is ported to the compiler interface.
1560 1562 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1561 1563
1562 1564 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1563 1565 Thread()
1564 1566 #if INCLUDE_ALL_GCS
1565 1567 , _satb_mark_queue(&_satb_mark_queue_set),
1566 1568 _dirty_card_queue(&_dirty_card_queue_set)
1567 1569 #endif // INCLUDE_ALL_GCS
1568 1570 {
1569 1571 if (TraceThreadEvents) {
1570 1572 tty->print_cr("creating thread %p", this);
1571 1573 }
1572 1574 initialize();
1573 1575 _jni_attach_state = _not_attaching_via_jni;
1574 1576 set_entry_point(entry_point);
1575 1577 // Create the native thread itself.
1576 1578 // %note runtime_23
1577 1579 os::ThreadType thr_type = os::java_thread;
1578 1580 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1579 1581 os::java_thread;
1580 1582 os::create_thread(this, thr_type, stack_sz);
1581 1583 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1582 1584 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1583 1585 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1584 1586 // the exception consists of creating the exception object & initializing it, initialization
1585 1587 // will leave the VM via a JavaCall and then all locks must be unlocked).
1586 1588 //
1587 1589 // The thread is still suspended when we reach here. Thread must be explicit started
1588 1590 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1589 1591 // by calling Threads:add. The reason why this is not done here, is because the thread
1590 1592 // object must be fully initialized (take a look at JVM_Start)
1591 1593 }
1592 1594
1593 1595 JavaThread::~JavaThread() {
1594 1596 if (TraceThreadEvents) {
1595 1597 tty->print_cr("terminate thread %p", this);
1596 1598 }
1597 1599
1598 1600 // JSR166 -- return the parker to the free list
1599 1601 Parker::Release(_parker);
1600 1602 _parker = NULL ;
1601 1603
1602 1604 // Free any remaining previous UnrollBlock
1603 1605 vframeArray* old_array = vframe_array_last();
1604 1606
1605 1607 if (old_array != NULL) {
1606 1608 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1607 1609 old_array->set_unroll_block(NULL);
1608 1610 delete old_info;
1609 1611 delete old_array;
1610 1612 }
1611 1613
1612 1614 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1613 1615 if (deferred != NULL) {
1614 1616 // This can only happen if thread is destroyed before deoptimization occurs.
1615 1617 assert(deferred->length() != 0, "empty array!");
1616 1618 do {
1617 1619 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1618 1620 deferred->remove_at(0);
1619 1621 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1620 1622 delete dlv;
1621 1623 } while (deferred->length() != 0);
1622 1624 delete deferred;
1623 1625 }
1624 1626
1625 1627 // All Java related clean up happens in exit
1626 1628 ThreadSafepointState::destroy(this);
1627 1629 if (_thread_profiler != NULL) delete _thread_profiler;
1628 1630 if (_thread_stat != NULL) delete _thread_stat;
1629 1631 }
1630 1632
1631 1633
1632 1634 // The first routine called by a new Java thread
1633 1635 void JavaThread::run() {
1634 1636 // initialize thread-local alloc buffer related fields
1635 1637 this->initialize_tlab();
1636 1638
1637 1639 // used to test validitity of stack trace backs
1638 1640 this->record_base_of_stack_pointer();
1639 1641
1640 1642 // Record real stack base and size.
1641 1643 this->record_stack_base_and_size();
1642 1644
1643 1645 // Initialize thread local storage; set before calling MutexLocker
1644 1646 this->initialize_thread_local_storage();
1645 1647
1646 1648 this->create_stack_guard_pages();
1647 1649
1648 1650 this->cache_global_variables();
1649 1651
1650 1652 // Thread is now sufficient initialized to be handled by the safepoint code as being
1651 1653 // in the VM. Change thread state from _thread_new to _thread_in_vm
1652 1654 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1653 1655
1654 1656 assert(JavaThread::current() == this, "sanity check");
1655 1657 assert(!Thread::current()->owns_locks(), "sanity check");
1656 1658
1657 1659 DTRACE_THREAD_PROBE(start, this);
1658 1660
1659 1661 // This operation might block. We call that after all safepoint checks for a new thread has
1660 1662 // been completed.
1661 1663 this->set_active_handles(JNIHandleBlock::allocate_block());
1662 1664
1663 1665 if (JvmtiExport::should_post_thread_life()) {
1664 1666 JvmtiExport::post_thread_start(this);
1665 1667 }
1666 1668
1667 1669 EventThreadStart event;
1668 1670 if (event.should_commit()) {
1669 1671 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1670 1672 event.commit();
1671 1673 }
1672 1674
1673 1675 // We call another function to do the rest so we are sure that the stack addresses used
1674 1676 // from there will be lower than the stack base just computed
1675 1677 thread_main_inner();
1676 1678
1677 1679 // Note, thread is no longer valid at this point!
1678 1680 }
1679 1681
1680 1682
1681 1683 void JavaThread::thread_main_inner() {
1682 1684 assert(JavaThread::current() == this, "sanity check");
1683 1685 assert(this->threadObj() != NULL, "just checking");
1684 1686
1685 1687 // Execute thread entry point unless this thread has a pending exception
1686 1688 // or has been stopped before starting.
1687 1689 // Note: Due to JVM_StopThread we can have pending exceptions already!
1688 1690 if (!this->has_pending_exception() &&
1689 1691 !java_lang_Thread::is_stillborn(this->threadObj())) {
1690 1692 {
1691 1693 ResourceMark rm(this);
1692 1694 this->set_native_thread_name(this->get_thread_name());
1693 1695 }
1694 1696 HandleMark hm(this);
1695 1697 this->entry_point()(this, this);
1696 1698 }
1697 1699
1698 1700 DTRACE_THREAD_PROBE(stop, this);
1699 1701
1700 1702 this->exit(false);
1701 1703 delete this;
1702 1704 }
1703 1705
1704 1706
1705 1707 static void ensure_join(JavaThread* thread) {
1706 1708 // We do not need to grap the Threads_lock, since we are operating on ourself.
1707 1709 Handle threadObj(thread, thread->threadObj());
1708 1710 assert(threadObj.not_null(), "java thread object must exist");
1709 1711 ObjectLocker lock(threadObj, thread);
1710 1712 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1711 1713 thread->clear_pending_exception();
1712 1714 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1713 1715 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1714 1716 // Clear the native thread instance - this makes isAlive return false and allows the join()
1715 1717 // to complete once we've done the notify_all below
1716 1718 java_lang_Thread::set_thread(threadObj(), NULL);
1717 1719 lock.notify_all(thread);
1718 1720 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1719 1721 thread->clear_pending_exception();
1720 1722 }
1721 1723
1722 1724
1723 1725 // For any new cleanup additions, please check to see if they need to be applied to
1724 1726 // cleanup_failed_attach_current_thread as well.
1725 1727 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1726 1728 assert(this == JavaThread::current(), "thread consistency check");
1727 1729
1728 1730 HandleMark hm(this);
1729 1731 Handle uncaught_exception(this, this->pending_exception());
1730 1732 this->clear_pending_exception();
1731 1733 Handle threadObj(this, this->threadObj());
1732 1734 assert(threadObj.not_null(), "Java thread object should be created");
1733 1735
1734 1736 if (get_thread_profiler() != NULL) {
1735 1737 get_thread_profiler()->disengage();
1736 1738 ResourceMark rm;
1737 1739 get_thread_profiler()->print(get_thread_name());
1738 1740 }
1739 1741
1740 1742
1741 1743 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1742 1744 {
1743 1745 EXCEPTION_MARK;
1744 1746
1745 1747 CLEAR_PENDING_EXCEPTION;
1746 1748 }
1747 1749 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1748 1750 // has to be fixed by a runtime query method
1749 1751 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1750 1752 // JSR-166: change call from from ThreadGroup.uncaughtException to
1751 1753 // java.lang.Thread.dispatchUncaughtException
1752 1754 if (uncaught_exception.not_null()) {
1753 1755 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1754 1756 {
1755 1757 EXCEPTION_MARK;
1756 1758 // Check if the method Thread.dispatchUncaughtException() exists. If so
1757 1759 // call it. Otherwise we have an older library without the JSR-166 changes,
1758 1760 // so call ThreadGroup.uncaughtException()
1759 1761 KlassHandle recvrKlass(THREAD, threadObj->klass());
1760 1762 CallInfo callinfo;
1761 1763 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1762 1764 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1763 1765 vmSymbols::dispatchUncaughtException_name(),
1764 1766 vmSymbols::throwable_void_signature(),
1765 1767 KlassHandle(), false, false, THREAD);
1766 1768 CLEAR_PENDING_EXCEPTION;
1767 1769 methodHandle method = callinfo.selected_method();
1768 1770 if (method.not_null()) {
1769 1771 JavaValue result(T_VOID);
1770 1772 JavaCalls::call_virtual(&result,
1771 1773 threadObj, thread_klass,
1772 1774 vmSymbols::dispatchUncaughtException_name(),
1773 1775 vmSymbols::throwable_void_signature(),
1774 1776 uncaught_exception,
1775 1777 THREAD);
1776 1778 } else {
1777 1779 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1778 1780 JavaValue result(T_VOID);
1779 1781 JavaCalls::call_virtual(&result,
1780 1782 group, thread_group,
1781 1783 vmSymbols::uncaughtException_name(),
1782 1784 vmSymbols::thread_throwable_void_signature(),
1783 1785 threadObj, // Arg 1
1784 1786 uncaught_exception, // Arg 2
1785 1787 THREAD);
1786 1788 }
1787 1789 if (HAS_PENDING_EXCEPTION) {
1788 1790 ResourceMark rm(this);
1789 1791 jio_fprintf(defaultStream::error_stream(),
1790 1792 "\nException: %s thrown from the UncaughtExceptionHandler"
1791 1793 " in thread \"%s\"\n",
1792 1794 pending_exception()->klass()->external_name(),
1793 1795 get_thread_name());
1794 1796 CLEAR_PENDING_EXCEPTION;
1795 1797 }
1796 1798 }
1797 1799 }
1798 1800
1799 1801 // Called before the java thread exit since we want to read info
1800 1802 // from java_lang_Thread object
1801 1803 EventThreadEnd event;
1802 1804 if (event.should_commit()) {
1803 1805 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj()));
1804 1806 event.commit();
1805 1807 }
1806 1808
1807 1809 // Call after last event on thread
1808 1810 EVENT_THREAD_EXIT(this);
1809 1811
1810 1812 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1811 1813 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1812 1814 // is deprecated anyhow.
1813 1815 if (!is_Compiler_thread()) {
1814 1816 int count = 3;
1815 1817 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1816 1818 EXCEPTION_MARK;
1817 1819 JavaValue result(T_VOID);
1818 1820 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1819 1821 JavaCalls::call_virtual(&result,
1820 1822 threadObj, thread_klass,
1821 1823 vmSymbols::exit_method_name(),
1822 1824 vmSymbols::void_method_signature(),
1823 1825 THREAD);
1824 1826 CLEAR_PENDING_EXCEPTION;
1825 1827 }
1826 1828 }
1827 1829 // notify JVMTI
1828 1830 if (JvmtiExport::should_post_thread_life()) {
1829 1831 JvmtiExport::post_thread_end(this);
1830 1832 }
1831 1833
1832 1834 // We have notified the agents that we are exiting, before we go on,
1833 1835 // we must check for a pending external suspend request and honor it
1834 1836 // in order to not surprise the thread that made the suspend request.
1835 1837 while (true) {
1836 1838 {
1837 1839 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1838 1840 if (!is_external_suspend()) {
1839 1841 set_terminated(_thread_exiting);
1840 1842 ThreadService::current_thread_exiting(this);
1841 1843 break;
1842 1844 }
1843 1845 // Implied else:
1844 1846 // Things get a little tricky here. We have a pending external
1845 1847 // suspend request, but we are holding the SR_lock so we
1846 1848 // can't just self-suspend. So we temporarily drop the lock
1847 1849 // and then self-suspend.
1848 1850 }
1849 1851
1850 1852 ThreadBlockInVM tbivm(this);
1851 1853 java_suspend_self();
1852 1854
1853 1855 // We're done with this suspend request, but we have to loop around
1854 1856 // and check again. Eventually we will get SR_lock without a pending
1855 1857 // external suspend request and will be able to mark ourselves as
1856 1858 // exiting.
1857 1859 }
1858 1860 // no more external suspends are allowed at this point
1859 1861 } else {
1860 1862 // before_exit() has already posted JVMTI THREAD_END events
1861 1863 }
1862 1864
1863 1865 // Notify waiters on thread object. This has to be done after exit() is called
1864 1866 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1865 1867 // group should have the destroyed bit set before waiters are notified).
1866 1868 ensure_join(this);
1867 1869 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1868 1870
1869 1871 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1870 1872 // held by this thread must be released. A detach operation must only
1871 1873 // get here if there are no Java frames on the stack. Therefore, any
1872 1874 // owned monitors at this point MUST be JNI-acquired monitors which are
1873 1875 // pre-inflated and in the monitor cache.
1874 1876 //
1875 1877 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1876 1878 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1877 1879 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1878 1880 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1879 1881 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1880 1882 }
1881 1883
1882 1884 // These things needs to be done while we are still a Java Thread. Make sure that thread
1883 1885 // is in a consistent state, in case GC happens
1884 1886 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1885 1887
1886 1888 if (active_handles() != NULL) {
1887 1889 JNIHandleBlock* block = active_handles();
1888 1890 set_active_handles(NULL);
1889 1891 JNIHandleBlock::release_block(block);
1890 1892 }
1891 1893
1892 1894 if (free_handle_block() != NULL) {
1893 1895 JNIHandleBlock* block = free_handle_block();
1894 1896 set_free_handle_block(NULL);
1895 1897 JNIHandleBlock::release_block(block);
1896 1898 }
1897 1899
1898 1900 // These have to be removed while this is still a valid thread.
1899 1901 remove_stack_guard_pages();
1900 1902
1901 1903 if (UseTLAB) {
1902 1904 tlab().make_parsable(true); // retire TLAB
1903 1905 }
1904 1906
1905 1907 if (JvmtiEnv::environments_might_exist()) {
1906 1908 JvmtiExport::cleanup_thread(this);
1907 1909 }
1908 1910
1909 1911 // We must flush any deferred card marks before removing a thread from
1910 1912 // the list of active threads.
1911 1913 Universe::heap()->flush_deferred_store_barrier(this);
1912 1914 assert(deferred_card_mark().is_empty(), "Should have been flushed");
1913 1915
1914 1916 #if INCLUDE_ALL_GCS
1915 1917 // We must flush the G1-related buffers before removing a thread
1916 1918 // from the list of active threads. We must do this after any deferred
1917 1919 // card marks have been flushed (above) so that any entries that are
1918 1920 // added to the thread's dirty card queue as a result are not lost.
1919 1921 if (UseG1GC) {
1920 1922 flush_barrier_queues();
1921 1923 }
1922 1924 #endif // INCLUDE_ALL_GCS
1923 1925
1924 1926 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1925 1927 Threads::remove(this);
1926 1928 }
1927 1929
1928 1930 #if INCLUDE_ALL_GCS
1929 1931 // Flush G1-related queues.
1930 1932 void JavaThread::flush_barrier_queues() {
1931 1933 satb_mark_queue().flush();
1932 1934 dirty_card_queue().flush();
1933 1935 }
1934 1936
1935 1937 void JavaThread::initialize_queues() {
1936 1938 assert(!SafepointSynchronize::is_at_safepoint(),
1937 1939 "we should not be at a safepoint");
1938 1940
1939 1941 ObjPtrQueue& satb_queue = satb_mark_queue();
1940 1942 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1941 1943 // The SATB queue should have been constructed with its active
1942 1944 // field set to false.
1943 1945 assert(!satb_queue.is_active(), "SATB queue should not be active");
1944 1946 assert(satb_queue.is_empty(), "SATB queue should be empty");
1945 1947 // If we are creating the thread during a marking cycle, we should
1946 1948 // set the active field of the SATB queue to true.
1947 1949 if (satb_queue_set.is_active()) {
1948 1950 satb_queue.set_active(true);
1949 1951 }
1950 1952
1951 1953 DirtyCardQueue& dirty_queue = dirty_card_queue();
1952 1954 // The dirty card queue should have been constructed with its
1953 1955 // active field set to true.
1954 1956 assert(dirty_queue.is_active(), "dirty card queue should be active");
1955 1957 }
1956 1958 #endif // INCLUDE_ALL_GCS
1957 1959
1958 1960 void JavaThread::cleanup_failed_attach_current_thread() {
1959 1961 if (get_thread_profiler() != NULL) {
1960 1962 get_thread_profiler()->disengage();
1961 1963 ResourceMark rm;
1962 1964 get_thread_profiler()->print(get_thread_name());
1963 1965 }
1964 1966
1965 1967 if (active_handles() != NULL) {
1966 1968 JNIHandleBlock* block = active_handles();
1967 1969 set_active_handles(NULL);
1968 1970 JNIHandleBlock::release_block(block);
1969 1971 }
1970 1972
1971 1973 if (free_handle_block() != NULL) {
1972 1974 JNIHandleBlock* block = free_handle_block();
1973 1975 set_free_handle_block(NULL);
1974 1976 JNIHandleBlock::release_block(block);
1975 1977 }
1976 1978
1977 1979 // These have to be removed while this is still a valid thread.
1978 1980 remove_stack_guard_pages();
1979 1981
1980 1982 if (UseTLAB) {
1981 1983 tlab().make_parsable(true); // retire TLAB, if any
1982 1984 }
1983 1985
1984 1986 #if INCLUDE_ALL_GCS
1985 1987 if (UseG1GC) {
1986 1988 flush_barrier_queues();
1987 1989 }
1988 1990 #endif // INCLUDE_ALL_GCS
1989 1991
1990 1992 Threads::remove(this);
1991 1993 delete this;
1992 1994 }
1993 1995
1994 1996
1995 1997
1996 1998
1997 1999 JavaThread* JavaThread::active() {
1998 2000 Thread* thread = ThreadLocalStorage::thread();
1999 2001 assert(thread != NULL, "just checking");
2000 2002 if (thread->is_Java_thread()) {
2001 2003 return (JavaThread*) thread;
2002 2004 } else {
2003 2005 assert(thread->is_VM_thread(), "this must be a vm thread");
2004 2006 VM_Operation* op = ((VMThread*) thread)->vm_operation();
2005 2007 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
2006 2008 assert(ret->is_Java_thread(), "must be a Java thread");
2007 2009 return ret;
2008 2010 }
2009 2011 }
2010 2012
2011 2013 bool JavaThread::is_lock_owned(address adr) const {
2012 2014 if (Thread::is_lock_owned(adr)) return true;
2013 2015
2014 2016 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2015 2017 if (chunk->contains(adr)) return true;
2016 2018 }
2017 2019
2018 2020 return false;
2019 2021 }
2020 2022
2021 2023
2022 2024 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
2023 2025 chunk->set_next(monitor_chunks());
2024 2026 set_monitor_chunks(chunk);
2025 2027 }
2026 2028
2027 2029 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
2028 2030 guarantee(monitor_chunks() != NULL, "must be non empty");
2029 2031 if (monitor_chunks() == chunk) {
2030 2032 set_monitor_chunks(chunk->next());
2031 2033 } else {
2032 2034 MonitorChunk* prev = monitor_chunks();
2033 2035 while (prev->next() != chunk) prev = prev->next();
2034 2036 prev->set_next(chunk->next());
2035 2037 }
2036 2038 }
2037 2039
2038 2040 // JVM support.
2039 2041
2040 2042 // Note: this function shouldn't block if it's called in
2041 2043 // _thread_in_native_trans state (such as from
2042 2044 // check_special_condition_for_native_trans()).
2043 2045 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
2044 2046
2045 2047 if (has_last_Java_frame() && has_async_condition()) {
2046 2048 // If we are at a polling page safepoint (not a poll return)
2047 2049 // then we must defer async exception because live registers
2048 2050 // will be clobbered by the exception path. Poll return is
2049 2051 // ok because the call we a returning from already collides
2050 2052 // with exception handling registers and so there is no issue.
2051 2053 // (The exception handling path kills call result registers but
2052 2054 // this is ok since the exception kills the result anyway).
2053 2055
2054 2056 if (is_at_poll_safepoint()) {
2055 2057 // if the code we are returning to has deoptimized we must defer
2056 2058 // the exception otherwise live registers get clobbered on the
2057 2059 // exception path before deoptimization is able to retrieve them.
2058 2060 //
2059 2061 RegisterMap map(this, false);
2060 2062 frame caller_fr = last_frame().sender(&map);
2061 2063 assert(caller_fr.is_compiled_frame(), "what?");
2062 2064 if (caller_fr.is_deoptimized_frame()) {
2063 2065 if (TraceExceptions) {
2064 2066 ResourceMark rm;
2065 2067 tty->print_cr("deferred async exception at compiled safepoint");
2066 2068 }
2067 2069 return;
2068 2070 }
2069 2071 }
2070 2072 }
2071 2073
2072 2074 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
2073 2075 if (condition == _no_async_condition) {
2074 2076 // Conditions have changed since has_special_runtime_exit_condition()
2075 2077 // was called:
2076 2078 // - if we were here only because of an external suspend request,
2077 2079 // then that was taken care of above (or cancelled) so we are done
2078 2080 // - if we were here because of another async request, then it has
2079 2081 // been cleared between the has_special_runtime_exit_condition()
2080 2082 // and now so again we are done
2081 2083 return;
2082 2084 }
2083 2085
2084 2086 // Check for pending async. exception
2085 2087 if (_pending_async_exception != NULL) {
2086 2088 // Only overwrite an already pending exception, if it is not a threadDeath.
2087 2089 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
2088 2090
2089 2091 // We cannot call Exceptions::_throw(...) here because we cannot block
2090 2092 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
2091 2093
2092 2094 if (TraceExceptions) {
2093 2095 ResourceMark rm;
2094 2096 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
2095 2097 if (has_last_Java_frame() ) {
2096 2098 frame f = last_frame();
2097 2099 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
2098 2100 }
2099 2101 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2100 2102 }
2101 2103 _pending_async_exception = NULL;
2102 2104 clear_has_async_exception();
2103 2105 }
2104 2106 }
2105 2107
2106 2108 if (check_unsafe_error &&
2107 2109 condition == _async_unsafe_access_error && !has_pending_exception()) {
2108 2110 condition = _no_async_condition; // done
2109 2111 switch (thread_state()) {
2110 2112 case _thread_in_vm:
2111 2113 {
2112 2114 JavaThread* THREAD = this;
2113 2115 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2114 2116 }
2115 2117 case _thread_in_native:
2116 2118 {
2117 2119 ThreadInVMfromNative tiv(this);
2118 2120 JavaThread* THREAD = this;
2119 2121 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
2120 2122 }
2121 2123 case _thread_in_Java:
2122 2124 {
2123 2125 ThreadInVMfromJava tiv(this);
2124 2126 JavaThread* THREAD = this;
2125 2127 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
2126 2128 }
2127 2129 default:
2128 2130 ShouldNotReachHere();
2129 2131 }
2130 2132 }
2131 2133
2132 2134 assert(condition == _no_async_condition || has_pending_exception() ||
2133 2135 (!check_unsafe_error && condition == _async_unsafe_access_error),
2134 2136 "must have handled the async condition, if no exception");
2135 2137 }
2136 2138
2137 2139 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
2138 2140 //
2139 2141 // Check for pending external suspend. Internal suspend requests do
2140 2142 // not use handle_special_runtime_exit_condition().
2141 2143 // If JNIEnv proxies are allowed, don't self-suspend if the target
2142 2144 // thread is not the current thread. In older versions of jdbx, jdbx
2143 2145 // threads could call into the VM with another thread's JNIEnv so we
2144 2146 // can be here operating on behalf of a suspended thread (4432884).
2145 2147 bool do_self_suspend = is_external_suspend_with_lock();
2146 2148 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
2147 2149 //
2148 2150 // Because thread is external suspended the safepoint code will count
2149 2151 // thread as at a safepoint. This can be odd because we can be here
2150 2152 // as _thread_in_Java which would normally transition to _thread_blocked
2151 2153 // at a safepoint. We would like to mark the thread as _thread_blocked
2152 2154 // before calling java_suspend_self like all other callers of it but
2153 2155 // we must then observe proper safepoint protocol. (We can't leave
2154 2156 // _thread_blocked with a safepoint in progress). However we can be
2155 2157 // here as _thread_in_native_trans so we can't use a normal transition
2156 2158 // constructor/destructor pair because they assert on that type of
2157 2159 // transition. We could do something like:
2158 2160 //
2159 2161 // JavaThreadState state = thread_state();
2160 2162 // set_thread_state(_thread_in_vm);
2161 2163 // {
2162 2164 // ThreadBlockInVM tbivm(this);
2163 2165 // java_suspend_self()
2164 2166 // }
2165 2167 // set_thread_state(_thread_in_vm_trans);
2166 2168 // if (safepoint) block;
2167 2169 // set_thread_state(state);
2168 2170 //
2169 2171 // but that is pretty messy. Instead we just go with the way the
2170 2172 // code has worked before and note that this is the only path to
2171 2173 // java_suspend_self that doesn't put the thread in _thread_blocked
2172 2174 // mode.
2173 2175
2174 2176 frame_anchor()->make_walkable(this);
2175 2177 java_suspend_self();
2176 2178
2177 2179 // We might be here for reasons in addition to the self-suspend request
2178 2180 // so check for other async requests.
2179 2181 }
2180 2182
2181 2183 if (check_asyncs) {
2182 2184 check_and_handle_async_exceptions();
2183 2185 }
2184 2186 }
2185 2187
2186 2188 void JavaThread::send_thread_stop(oop java_throwable) {
2187 2189 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
2188 2190 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
2189 2191 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
2190 2192
2191 2193 // Do not throw asynchronous exceptions against the compiler thread
2192 2194 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
2193 2195 if (is_Compiler_thread()) return;
2194 2196
2195 2197 {
2196 2198 // Actually throw the Throwable against the target Thread - however
2197 2199 // only if there is no thread death exception installed already.
2198 2200 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
2199 2201 // If the topmost frame is a runtime stub, then we are calling into
2200 2202 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
2201 2203 // must deoptimize the caller before continuing, as the compiled exception handler table
2202 2204 // may not be valid
2203 2205 if (has_last_Java_frame()) {
2204 2206 frame f = last_frame();
2205 2207 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
2206 2208 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2207 2209 RegisterMap reg_map(this, UseBiasedLocking);
2208 2210 frame compiled_frame = f.sender(®_map);
2209 2211 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
2210 2212 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2211 2213 }
2212 2214 }
2213 2215 }
2214 2216
2215 2217 // Set async. pending exception in thread.
2216 2218 set_pending_async_exception(java_throwable);
2217 2219
2218 2220 if (TraceExceptions) {
2219 2221 ResourceMark rm;
2220 2222 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name());
2221 2223 }
2222 2224 // for AbortVMOnException flag
2223 2225 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()));
2224 2226 }
2225 2227 }
2226 2228
2227 2229
2228 2230 // Interrupt thread so it will wake up from a potential wait()
2229 2231 Thread::interrupt(this);
2230 2232 }
2231 2233
2232 2234 // External suspension mechanism.
2233 2235 //
2234 2236 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2235 2237 // to any VM_locks and it is at a transition
2236 2238 // Self-suspension will happen on the transition out of the vm.
2237 2239 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2238 2240 //
2239 2241 // Guarantees on return:
2240 2242 // + Target thread will not execute any new bytecode (that's why we need to
2241 2243 // force a safepoint)
2242 2244 // + Target thread will not enter any new monitors
2243 2245 //
2244 2246 void JavaThread::java_suspend() {
2245 2247 { MutexLocker mu(Threads_lock);
2246 2248 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2247 2249 return;
2248 2250 }
2249 2251 }
2250 2252
2251 2253 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2252 2254 if (!is_external_suspend()) {
2253 2255 // a racing resume has cancelled us; bail out now
2254 2256 return;
2255 2257 }
2256 2258
2257 2259 // suspend is done
2258 2260 uint32_t debug_bits = 0;
2259 2261 // Warning: is_ext_suspend_completed() may temporarily drop the
2260 2262 // SR_lock to allow the thread to reach a stable thread state if
2261 2263 // it is currently in a transient thread state.
2262 2264 if (is_ext_suspend_completed(false /* !called_by_wait */,
2263 2265 SuspendRetryDelay, &debug_bits) ) {
2264 2266 return;
2265 2267 }
2266 2268 }
2267 2269
2268 2270 VM_ForceSafepoint vm_suspend;
2269 2271 VMThread::execute(&vm_suspend);
2270 2272 }
2271 2273
2272 2274 // Part II of external suspension.
2273 2275 // A JavaThread self suspends when it detects a pending external suspend
2274 2276 // request. This is usually on transitions. It is also done in places
2275 2277 // where continuing to the next transition would surprise the caller,
2276 2278 // e.g., monitor entry.
2277 2279 //
2278 2280 // Returns the number of times that the thread self-suspended.
2279 2281 //
2280 2282 // Note: DO NOT call java_suspend_self() when you just want to block current
2281 2283 // thread. java_suspend_self() is the second stage of cooperative
2282 2284 // suspension for external suspend requests and should only be used
2283 2285 // to complete an external suspend request.
2284 2286 //
2285 2287 int JavaThread::java_suspend_self() {
2286 2288 int ret = 0;
2287 2289
2288 2290 // we are in the process of exiting so don't suspend
2289 2291 if (is_exiting()) {
2290 2292 clear_external_suspend();
2291 2293 return ret;
2292 2294 }
2293 2295
2294 2296 assert(_anchor.walkable() ||
2295 2297 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2296 2298 "must have walkable stack");
2297 2299
2298 2300 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2299 2301
2300 2302 assert(!this->is_ext_suspended(),
2301 2303 "a thread trying to self-suspend should not already be suspended");
2302 2304
2303 2305 if (this->is_suspend_equivalent()) {
2304 2306 // If we are self-suspending as a result of the lifting of a
2305 2307 // suspend equivalent condition, then the suspend_equivalent
2306 2308 // flag is not cleared until we set the ext_suspended flag so
2307 2309 // that wait_for_ext_suspend_completion() returns consistent
2308 2310 // results.
2309 2311 this->clear_suspend_equivalent();
2310 2312 }
2311 2313
2312 2314 // A racing resume may have cancelled us before we grabbed SR_lock
2313 2315 // above. Or another external suspend request could be waiting for us
2314 2316 // by the time we return from SR_lock()->wait(). The thread
2315 2317 // that requested the suspension may already be trying to walk our
2316 2318 // stack and if we return now, we can change the stack out from under
2317 2319 // it. This would be a "bad thing (TM)" and cause the stack walker
2318 2320 // to crash. We stay self-suspended until there are no more pending
2319 2321 // external suspend requests.
2320 2322 while (is_external_suspend()) {
2321 2323 ret++;
2322 2324 this->set_ext_suspended();
2323 2325
2324 2326 // _ext_suspended flag is cleared by java_resume()
2325 2327 while (is_ext_suspended()) {
2326 2328 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2327 2329 }
2328 2330 }
2329 2331
2330 2332 return ret;
2331 2333 }
2332 2334
2333 2335 #ifdef ASSERT
2334 2336 // verify the JavaThread has not yet been published in the Threads::list, and
2335 2337 // hence doesn't need protection from concurrent access at this stage
2336 2338 void JavaThread::verify_not_published() {
2337 2339 if (!Threads_lock->owned_by_self()) {
2338 2340 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2339 2341 assert( !Threads::includes(this),
2340 2342 "java thread shouldn't have been published yet!");
2341 2343 }
2342 2344 else {
2343 2345 assert( !Threads::includes(this),
2344 2346 "java thread shouldn't have been published yet!");
2345 2347 }
2346 2348 }
2347 2349 #endif
2348 2350
2349 2351 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2350 2352 // progress or when _suspend_flags is non-zero.
2351 2353 // Current thread needs to self-suspend if there is a suspend request and/or
2352 2354 // block if a safepoint is in progress.
2353 2355 // Async exception ISN'T checked.
2354 2356 // Note only the ThreadInVMfromNative transition can call this function
2355 2357 // directly and when thread state is _thread_in_native_trans
2356 2358 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2357 2359 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2358 2360
2359 2361 JavaThread *curJT = JavaThread::current();
2360 2362 bool do_self_suspend = thread->is_external_suspend();
2361 2363
2362 2364 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2363 2365
2364 2366 // If JNIEnv proxies are allowed, don't self-suspend if the target
2365 2367 // thread is not the current thread. In older versions of jdbx, jdbx
2366 2368 // threads could call into the VM with another thread's JNIEnv so we
2367 2369 // can be here operating on behalf of a suspended thread (4432884).
2368 2370 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2369 2371 JavaThreadState state = thread->thread_state();
2370 2372
2371 2373 // We mark this thread_blocked state as a suspend-equivalent so
2372 2374 // that a caller to is_ext_suspend_completed() won't be confused.
2373 2375 // The suspend-equivalent state is cleared by java_suspend_self().
2374 2376 thread->set_suspend_equivalent();
2375 2377
2376 2378 // If the safepoint code sees the _thread_in_native_trans state, it will
2377 2379 // wait until the thread changes to other thread state. There is no
2378 2380 // guarantee on how soon we can obtain the SR_lock and complete the
2379 2381 // self-suspend request. It would be a bad idea to let safepoint wait for
2380 2382 // too long. Temporarily change the state to _thread_blocked to
2381 2383 // let the VM thread know that this thread is ready for GC. The problem
2382 2384 // of changing thread state is that safepoint could happen just after
2383 2385 // java_suspend_self() returns after being resumed, and VM thread will
2384 2386 // see the _thread_blocked state. We must check for safepoint
2385 2387 // after restoring the state and make sure we won't leave while a safepoint
2386 2388 // is in progress.
2387 2389 thread->set_thread_state(_thread_blocked);
2388 2390 thread->java_suspend_self();
2389 2391 thread->set_thread_state(state);
2390 2392 // Make sure new state is seen by VM thread
2391 2393 if (os::is_MP()) {
2392 2394 if (UseMembar) {
2393 2395 // Force a fence between the write above and read below
2394 2396 OrderAccess::fence();
2395 2397 } else {
2396 2398 // Must use this rather than serialization page in particular on Windows
2397 2399 InterfaceSupport::serialize_memory(thread);
2398 2400 }
2399 2401 }
2400 2402 }
2401 2403
2402 2404 if (SafepointSynchronize::do_call_back()) {
2403 2405 // If we are safepointing, then block the caller which may not be
2404 2406 // the same as the target thread (see above).
2405 2407 SafepointSynchronize::block(curJT);
2406 2408 }
2407 2409
2408 2410 if (thread->is_deopt_suspend()) {
2409 2411 thread->clear_deopt_suspend();
2410 2412 RegisterMap map(thread, false);
2411 2413 frame f = thread->last_frame();
2412 2414 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2413 2415 f = f.sender(&map);
2414 2416 }
2415 2417 if (f.id() == thread->must_deopt_id()) {
2416 2418 thread->clear_must_deopt_id();
2417 2419 f.deoptimize(thread);
2418 2420 } else {
2419 2421 fatal("missed deoptimization!");
2420 2422 }
2421 2423 }
2422 2424 }
2423 2425
2424 2426 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2425 2427 // progress or when _suspend_flags is non-zero.
2426 2428 // Current thread needs to self-suspend if there is a suspend request and/or
2427 2429 // block if a safepoint is in progress.
2428 2430 // Also check for pending async exception (not including unsafe access error).
2429 2431 // Note only the native==>VM/Java barriers can call this function and when
2430 2432 // thread state is _thread_in_native_trans.
2431 2433 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2432 2434 check_safepoint_and_suspend_for_native_trans(thread);
2433 2435
2434 2436 if (thread->has_async_exception()) {
2435 2437 // We are in _thread_in_native_trans state, don't handle unsafe
2436 2438 // access error since that may block.
2437 2439 thread->check_and_handle_async_exceptions(false);
2438 2440 }
2439 2441 }
2440 2442
2441 2443 // This is a variant of the normal
2442 2444 // check_special_condition_for_native_trans with slightly different
2443 2445 // semantics for use by critical native wrappers. It does all the
2444 2446 // normal checks but also performs the transition back into
2445 2447 // thread_in_Java state. This is required so that critical natives
2446 2448 // can potentially block and perform a GC if they are the last thread
2447 2449 // exiting the GC_locker.
2448 2450 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
2449 2451 check_special_condition_for_native_trans(thread);
2450 2452
2451 2453 // Finish the transition
2452 2454 thread->set_thread_state(_thread_in_Java);
2453 2455
2454 2456 if (thread->do_critical_native_unlock()) {
2455 2457 ThreadInVMfromJavaNoAsyncException tiv(thread);
2456 2458 GC_locker::unlock_critical(thread);
2457 2459 thread->clear_critical_native_unlock();
2458 2460 }
2459 2461 }
2460 2462
2461 2463 // We need to guarantee the Threads_lock here, since resumes are not
2462 2464 // allowed during safepoint synchronization
2463 2465 // Can only resume from an external suspension
2464 2466 void JavaThread::java_resume() {
2465 2467 assert_locked_or_safepoint(Threads_lock);
2466 2468
2467 2469 // Sanity check: thread is gone, has started exiting or the thread
2468 2470 // was not externally suspended.
2469 2471 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2470 2472 return;
2471 2473 }
2472 2474
2473 2475 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2474 2476
2475 2477 clear_external_suspend();
2476 2478
2477 2479 if (is_ext_suspended()) {
2478 2480 clear_ext_suspended();
2479 2481 SR_lock()->notify_all();
2480 2482 }
2481 2483 }
2482 2484
2483 2485 void JavaThread::create_stack_guard_pages() {
2484 2486 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2485 2487 address low_addr = stack_base() - stack_size();
2486 2488 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2487 2489
2488 2490 int allocate = os::allocate_stack_guard_pages();
2489 2491 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2490 2492
2491 2493 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2492 2494 warning("Attempt to allocate stack guard pages failed.");
2493 2495 return;
2494 2496 }
2495 2497
2496 2498 if (os::guard_memory((char *) low_addr, len)) {
2497 2499 _stack_guard_state = stack_guard_enabled;
2498 2500 } else {
2499 2501 warning("Attempt to protect stack guard pages failed.");
2500 2502 if (os::uncommit_memory((char *) low_addr, len)) {
2501 2503 warning("Attempt to deallocate stack guard pages failed.");
2502 2504 }
2503 2505 }
2504 2506 }
2505 2507
2506 2508 void JavaThread::remove_stack_guard_pages() {
2507 2509 assert(Thread::current() == this, "from different thread");
2508 2510 if (_stack_guard_state == stack_guard_unused) return;
2509 2511 address low_addr = stack_base() - stack_size();
2510 2512 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2511 2513
2512 2514 if (os::allocate_stack_guard_pages()) {
2513 2515 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2514 2516 _stack_guard_state = stack_guard_unused;
2515 2517 } else {
2516 2518 warning("Attempt to deallocate stack guard pages failed.");
2517 2519 }
2518 2520 } else {
2519 2521 if (_stack_guard_state == stack_guard_unused) return;
2520 2522 if (os::unguard_memory((char *) low_addr, len)) {
2521 2523 _stack_guard_state = stack_guard_unused;
2522 2524 } else {
2523 2525 warning("Attempt to unprotect stack guard pages failed.");
2524 2526 }
2525 2527 }
2526 2528 }
2527 2529
2528 2530 void JavaThread::enable_stack_yellow_zone() {
2529 2531 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2530 2532 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2531 2533
2532 2534 // The base notation is from the stacks point of view, growing downward.
2533 2535 // We need to adjust it to work correctly with guard_memory()
2534 2536 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2535 2537
2536 2538 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2537 2539 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2538 2540
2539 2541 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2540 2542 _stack_guard_state = stack_guard_enabled;
2541 2543 } else {
2542 2544 warning("Attempt to guard stack yellow zone failed.");
2543 2545 }
2544 2546 enable_register_stack_guard();
2545 2547 }
2546 2548
2547 2549 void JavaThread::disable_stack_yellow_zone() {
2548 2550 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2549 2551 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2550 2552
2551 2553 // Simply return if called for a thread that does not use guard pages.
2552 2554 if (_stack_guard_state == stack_guard_unused) return;
2553 2555
2554 2556 // The base notation is from the stacks point of view, growing downward.
2555 2557 // We need to adjust it to work correctly with guard_memory()
2556 2558 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2557 2559
2558 2560 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2559 2561 _stack_guard_state = stack_guard_yellow_disabled;
2560 2562 } else {
2561 2563 warning("Attempt to unguard stack yellow zone failed.");
2562 2564 }
2563 2565 disable_register_stack_guard();
2564 2566 }
2565 2567
2566 2568 void JavaThread::enable_stack_red_zone() {
2567 2569 // The base notation is from the stacks point of view, growing downward.
2568 2570 // We need to adjust it to work correctly with guard_memory()
2569 2571 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2570 2572 address base = stack_red_zone_base() - stack_red_zone_size();
2571 2573
2572 2574 guarantee(base < stack_base(),"Error calculating stack red zone");
2573 2575 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2574 2576
2575 2577 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2576 2578 warning("Attempt to guard stack red zone failed.");
2577 2579 }
2578 2580 }
2579 2581
2580 2582 void JavaThread::disable_stack_red_zone() {
2581 2583 // The base notation is from the stacks point of view, growing downward.
2582 2584 // We need to adjust it to work correctly with guard_memory()
2583 2585 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2584 2586 address base = stack_red_zone_base() - stack_red_zone_size();
2585 2587 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2586 2588 warning("Attempt to unguard stack red zone failed.");
2587 2589 }
2588 2590 }
2589 2591
2590 2592 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2591 2593 // ignore is there is no stack
2592 2594 if (!has_last_Java_frame()) return;
2593 2595 // traverse the stack frames. Starts from top frame.
2594 2596 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2595 2597 frame* fr = fst.current();
2596 2598 f(fr, fst.register_map());
2597 2599 }
2598 2600 }
2599 2601
2600 2602
2601 2603 #ifndef PRODUCT
2602 2604 // Deoptimization
2603 2605 // Function for testing deoptimization
2604 2606 void JavaThread::deoptimize() {
2605 2607 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2606 2608 StackFrameStream fst(this, UseBiasedLocking);
2607 2609 bool deopt = false; // Dump stack only if a deopt actually happens.
2608 2610 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2609 2611 // Iterate over all frames in the thread and deoptimize
2610 2612 for(; !fst.is_done(); fst.next()) {
2611 2613 if(fst.current()->can_be_deoptimized()) {
2612 2614
2613 2615 if (only_at) {
2614 2616 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2615 2617 // consists of comma or carriage return separated numbers so
2616 2618 // search for the current bci in that string.
2617 2619 address pc = fst.current()->pc();
2618 2620 nmethod* nm = (nmethod*) fst.current()->cb();
2619 2621 ScopeDesc* sd = nm->scope_desc_at( pc);
2620 2622 char buffer[8];
2621 2623 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2622 2624 size_t len = strlen(buffer);
2623 2625 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2624 2626 while (found != NULL) {
2625 2627 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2626 2628 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2627 2629 // Check that the bci found is bracketed by terminators.
2628 2630 break;
2629 2631 }
2630 2632 found = strstr(found + 1, buffer);
2631 2633 }
2632 2634 if (!found) {
2633 2635 continue;
2634 2636 }
2635 2637 }
2636 2638
2637 2639 if (DebugDeoptimization && !deopt) {
2638 2640 deopt = true; // One-time only print before deopt
2639 2641 tty->print_cr("[BEFORE Deoptimization]");
2640 2642 trace_frames();
2641 2643 trace_stack();
2642 2644 }
2643 2645 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2644 2646 }
2645 2647 }
2646 2648
2647 2649 if (DebugDeoptimization && deopt) {
2648 2650 tty->print_cr("[AFTER Deoptimization]");
2649 2651 trace_frames();
2650 2652 }
2651 2653 }
2652 2654
2653 2655
2654 2656 // Make zombies
2655 2657 void JavaThread::make_zombies() {
2656 2658 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2657 2659 if (fst.current()->can_be_deoptimized()) {
2658 2660 // it is a Java nmethod
2659 2661 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2660 2662 nm->make_not_entrant();
2661 2663 }
2662 2664 }
2663 2665 }
2664 2666 #endif // PRODUCT
2665 2667
2666 2668
2667 2669 void JavaThread::deoptimized_wrt_marked_nmethods() {
2668 2670 if (!has_last_Java_frame()) return;
2669 2671 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2670 2672 StackFrameStream fst(this, UseBiasedLocking);
2671 2673 for(; !fst.is_done(); fst.next()) {
2672 2674 if (fst.current()->should_be_deoptimized()) {
2673 2675 if (LogCompilation && xtty != NULL) {
2674 2676 nmethod* nm = fst.current()->cb()->as_nmethod_or_null();
2675 2677 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'",
2676 2678 this->name(), nm != NULL ? nm->compile_id() : -1);
2677 2679 }
2678 2680
2679 2681 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2680 2682 }
2681 2683 }
2682 2684 }
2683 2685
2684 2686
2685 2687 // GC support
2686 2688 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2687 2689
2688 2690 void JavaThread::gc_epilogue() {
2689 2691 frames_do(frame_gc_epilogue);
2690 2692 }
2691 2693
2692 2694
2693 2695 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2694 2696
2695 2697 void JavaThread::gc_prologue() {
2696 2698 frames_do(frame_gc_prologue);
2697 2699 }
2698 2700
2699 2701 // If the caller is a NamedThread, then remember, in the current scope,
2700 2702 // the given JavaThread in its _processed_thread field.
2701 2703 class RememberProcessedThread: public StackObj {
2702 2704 NamedThread* _cur_thr;
2703 2705 public:
2704 2706 RememberProcessedThread(JavaThread* jthr) {
2705 2707 Thread* thread = Thread::current();
2706 2708 if (thread->is_Named_thread()) {
2707 2709 _cur_thr = (NamedThread *)thread;
2708 2710 _cur_thr->set_processed_thread(jthr);
2709 2711 } else {
2710 2712 _cur_thr = NULL;
2711 2713 }
2712 2714 }
2713 2715
2714 2716 ~RememberProcessedThread() {
2715 2717 if (_cur_thr) {
2716 2718 _cur_thr->set_processed_thread(NULL);
2717 2719 }
2718 2720 }
2719 2721 };
2720 2722
2721 2723 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
2722 2724 // Verify that the deferred card marks have been flushed.
2723 2725 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2724 2726
2725 2727 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2726 2728 // since there may be more than one thread using each ThreadProfiler.
2727 2729
2728 2730 // Traverse the GCHandles
2729 2731 Thread::oops_do(f, cld_f, cf);
2730 2732
2731 2733 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2732 2734 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2733 2735
2734 2736 if (has_last_Java_frame()) {
2735 2737 // Record JavaThread to GC thread
2736 2738 RememberProcessedThread rpt(this);
2737 2739
2738 2740 // Traverse the privileged stack
2739 2741 if (_privileged_stack_top != NULL) {
2740 2742 _privileged_stack_top->oops_do(f);
2741 2743 }
2742 2744
2743 2745 // traverse the registered growable array
2744 2746 if (_array_for_gc != NULL) {
2745 2747 for (int index = 0; index < _array_for_gc->length(); index++) {
2746 2748 f->do_oop(_array_for_gc->adr_at(index));
2747 2749 }
2748 2750 }
2749 2751
2750 2752 // Traverse the monitor chunks
2751 2753 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2752 2754 chunk->oops_do(f);
2753 2755 }
2754 2756
2755 2757 // Traverse the execution stack
2756 2758 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2757 2759 fst.current()->oops_do(f, cld_f, cf, fst.register_map());
2758 2760 }
2759 2761 }
2760 2762
2761 2763 // callee_target is never live across a gc point so NULL it here should
2762 2764 // it still contain a methdOop.
2763 2765
2764 2766 set_callee_target(NULL);
2765 2767
2766 2768 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2767 2769 // If we have deferred set_locals there might be oops waiting to be
2768 2770 // written
2769 2771 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2770 2772 if (list != NULL) {
2771 2773 for (int i = 0; i < list->length(); i++) {
2772 2774 list->at(i)->oops_do(f);
2773 2775 }
2774 2776 }
2775 2777
2776 2778 // Traverse instance variables at the end since the GC may be moving things
2777 2779 // around using this function
2778 2780 f->do_oop((oop*) &_threadObj);
2779 2781 f->do_oop((oop*) &_vm_result);
2780 2782 f->do_oop((oop*) &_exception_oop);
2781 2783 f->do_oop((oop*) &_pending_async_exception);
2782 2784
2783 2785 if (jvmti_thread_state() != NULL) {
2784 2786 jvmti_thread_state()->oops_do(f);
2785 2787 }
2786 2788 }
2787 2789
2788 2790 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2789 2791 Thread::nmethods_do(cf); // (super method is a no-op)
2790 2792
2791 2793 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2792 2794 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2793 2795
2794 2796 if (has_last_Java_frame()) {
2795 2797 // Traverse the execution stack
2796 2798 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2797 2799 fst.current()->nmethods_do(cf);
2798 2800 }
2799 2801 }
2800 2802 }
2801 2803
2802 2804 void JavaThread::metadata_do(void f(Metadata*)) {
2803 2805 Thread::metadata_do(f);
2804 2806 if (has_last_Java_frame()) {
2805 2807 // Traverse the execution stack to call f() on the methods in the stack
2806 2808 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2807 2809 fst.current()->metadata_do(f);
2808 2810 }
2809 2811 } else if (is_Compiler_thread()) {
2810 2812 // need to walk ciMetadata in current compile tasks to keep alive.
2811 2813 CompilerThread* ct = (CompilerThread*)this;
2812 2814 if (ct->env() != NULL) {
2813 2815 ct->env()->metadata_do(f);
2814 2816 }
2815 2817 }
2816 2818 }
2817 2819
2818 2820 // Printing
2819 2821 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2820 2822 switch (_thread_state) {
2821 2823 case _thread_uninitialized: return "_thread_uninitialized";
2822 2824 case _thread_new: return "_thread_new";
2823 2825 case _thread_new_trans: return "_thread_new_trans";
2824 2826 case _thread_in_native: return "_thread_in_native";
2825 2827 case _thread_in_native_trans: return "_thread_in_native_trans";
2826 2828 case _thread_in_vm: return "_thread_in_vm";
2827 2829 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2828 2830 case _thread_in_Java: return "_thread_in_Java";
2829 2831 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2830 2832 case _thread_blocked: return "_thread_blocked";
2831 2833 case _thread_blocked_trans: return "_thread_blocked_trans";
2832 2834 default: return "unknown thread state";
2833 2835 }
2834 2836 }
2835 2837
2836 2838 #ifndef PRODUCT
2837 2839 void JavaThread::print_thread_state_on(outputStream *st) const {
2838 2840 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2839 2841 };
2840 2842 void JavaThread::print_thread_state() const {
2841 2843 print_thread_state_on(tty);
2842 2844 };
2843 2845 #endif // PRODUCT
2844 2846
2845 2847 // Called by Threads::print() for VM_PrintThreads operation
2846 2848 void JavaThread::print_on(outputStream *st) const {
2847 2849 st->print("\"%s\" ", get_thread_name());
2848 2850 oop thread_oop = threadObj();
2849 2851 if (thread_oop != NULL) {
2850 2852 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop));
2851 2853 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2852 2854 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
2853 2855 }
2854 2856 Thread::print_on(st);
2855 2857 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2856 2858 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2857 2859 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2858 2860 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2859 2861 }
2860 2862 #ifndef PRODUCT
2861 2863 print_thread_state_on(st);
2862 2864 _safepoint_state->print_on(st);
2863 2865 #endif // PRODUCT
2864 2866 }
2865 2867
2866 2868 // Called by fatal error handler. The difference between this and
2867 2869 // JavaThread::print() is that we can't grab lock or allocate memory.
2868 2870 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2869 2871 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2870 2872 oop thread_obj = threadObj();
2871 2873 if (thread_obj != NULL) {
2872 2874 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2873 2875 }
2874 2876 st->print(" [");
2875 2877 st->print("%s", _get_thread_state_name(_thread_state));
2876 2878 if (osthread()) {
2877 2879 st->print(", id=%d", osthread()->thread_id());
2878 2880 }
2879 2881 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2880 2882 _stack_base - _stack_size, _stack_base);
2881 2883 st->print("]");
2882 2884 return;
2883 2885 }
2884 2886
2885 2887 // Verification
2886 2888
2887 2889 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2888 2890
2889 2891 void JavaThread::verify() {
2890 2892 // Verify oops in the thread.
2891 2893 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL);
2892 2894
2893 2895 // Verify the stack frames.
2894 2896 frames_do(frame_verify);
2895 2897 }
2896 2898
2897 2899 // CR 6300358 (sub-CR 2137150)
2898 2900 // Most callers of this method assume that it can't return NULL but a
2899 2901 // thread may not have a name whilst it is in the process of attaching to
2900 2902 // the VM - see CR 6412693, and there are places where a JavaThread can be
2901 2903 // seen prior to having it's threadObj set (eg JNI attaching threads and
2902 2904 // if vm exit occurs during initialization). These cases can all be accounted
2903 2905 // for such that this method never returns NULL.
2904 2906 const char* JavaThread::get_thread_name() const {
2905 2907 #ifdef ASSERT
2906 2908 // early safepoints can hit while current thread does not yet have TLS
2907 2909 if (!SafepointSynchronize::is_at_safepoint()) {
2908 2910 Thread *cur = Thread::current();
2909 2911 if (!(cur->is_Java_thread() && cur == this)) {
2910 2912 // Current JavaThreads are allowed to get their own name without
2911 2913 // the Threads_lock.
2912 2914 assert_locked_or_safepoint(Threads_lock);
2913 2915 }
2914 2916 }
2915 2917 #endif // ASSERT
2916 2918 return get_thread_name_string();
2917 2919 }
2918 2920
2919 2921 // Returns a non-NULL representation of this thread's name, or a suitable
2920 2922 // descriptive string if there is no set name
2921 2923 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2922 2924 const char* name_str;
2923 2925 oop thread_obj = threadObj();
2924 2926 if (thread_obj != NULL) {
2925 2927 typeArrayOop name = java_lang_Thread::name(thread_obj);
2926 2928 if (name != NULL) {
2927 2929 if (buf == NULL) {
2928 2930 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2929 2931 }
2930 2932 else {
2931 2933 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2932 2934 }
2933 2935 }
2934 2936 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
2935 2937 name_str = "<no-name - thread is attaching>";
2936 2938 }
2937 2939 else {
2938 2940 name_str = Thread::name();
2939 2941 }
2940 2942 }
2941 2943 else {
2942 2944 name_str = Thread::name();
2943 2945 }
2944 2946 assert(name_str != NULL, "unexpected NULL thread name");
2945 2947 return name_str;
2946 2948 }
2947 2949
2948 2950
2949 2951 const char* JavaThread::get_threadgroup_name() const {
2950 2952 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2951 2953 oop thread_obj = threadObj();
2952 2954 if (thread_obj != NULL) {
2953 2955 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2954 2956 if (thread_group != NULL) {
2955 2957 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2956 2958 // ThreadGroup.name can be null
2957 2959 if (name != NULL) {
2958 2960 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2959 2961 return str;
2960 2962 }
2961 2963 }
2962 2964 }
2963 2965 return NULL;
2964 2966 }
2965 2967
2966 2968 const char* JavaThread::get_parent_name() const {
2967 2969 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2968 2970 oop thread_obj = threadObj();
2969 2971 if (thread_obj != NULL) {
2970 2972 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2971 2973 if (thread_group != NULL) {
2972 2974 oop parent = java_lang_ThreadGroup::parent(thread_group);
2973 2975 if (parent != NULL) {
2974 2976 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2975 2977 // ThreadGroup.name can be null
2976 2978 if (name != NULL) {
2977 2979 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2978 2980 return str;
2979 2981 }
2980 2982 }
2981 2983 }
2982 2984 }
2983 2985 return NULL;
2984 2986 }
2985 2987
2986 2988 ThreadPriority JavaThread::java_priority() const {
2987 2989 oop thr_oop = threadObj();
2988 2990 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2989 2991 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2990 2992 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2991 2993 return priority;
2992 2994 }
2993 2995
2994 2996 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2995 2997
2996 2998 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2997 2999 // Link Java Thread object <-> C++ Thread
2998 3000
2999 3001 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
3000 3002 // and put it into a new Handle. The Handle "thread_oop" can then
3001 3003 // be used to pass the C++ thread object to other methods.
3002 3004
3003 3005 // Set the Java level thread object (jthread) field of the
3004 3006 // new thread (a JavaThread *) to C++ thread object using the
3005 3007 // "thread_oop" handle.
3006 3008
3007 3009 // Set the thread field (a JavaThread *) of the
3008 3010 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
3009 3011
3010 3012 Handle thread_oop(Thread::current(),
3011 3013 JNIHandles::resolve_non_null(jni_thread));
3012 3014 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
3013 3015 "must be initialized");
3014 3016 set_threadObj(thread_oop());
3015 3017 java_lang_Thread::set_thread(thread_oop(), this);
3016 3018
3017 3019 if (prio == NoPriority) {
3018 3020 prio = java_lang_Thread::priority(thread_oop());
3019 3021 assert(prio != NoPriority, "A valid priority should be present");
3020 3022 }
3021 3023
3022 3024 // Push the Java priority down to the native thread; needs Threads_lock
3023 3025 Thread::set_priority(this, prio);
3024 3026
3025 3027 prepare_ext();
3026 3028
3027 3029 // Add the new thread to the Threads list and set it in motion.
3028 3030 // We must have threads lock in order to call Threads::add.
3029 3031 // It is crucial that we do not block before the thread is
3030 3032 // added to the Threads list for if a GC happens, then the java_thread oop
3031 3033 // will not be visited by GC.
3032 3034 Threads::add(this);
3033 3035 }
3034 3036
3035 3037 oop JavaThread::current_park_blocker() {
3036 3038 // Support for JSR-166 locks
3037 3039 oop thread_oop = threadObj();
3038 3040 if (thread_oop != NULL &&
3039 3041 JDK_Version::current().supports_thread_park_blocker()) {
3040 3042 return java_lang_Thread::park_blocker(thread_oop);
3041 3043 }
3042 3044 return NULL;
3043 3045 }
3044 3046
3045 3047
3046 3048 void JavaThread::print_stack_on(outputStream* st) {
3047 3049 if (!has_last_Java_frame()) return;
3048 3050 ResourceMark rm;
3049 3051 HandleMark hm;
3050 3052
3051 3053 RegisterMap reg_map(this);
3052 3054 vframe* start_vf = last_java_vframe(®_map);
3053 3055 int count = 0;
3054 3056 for (vframe* f = start_vf; f; f = f->sender() ) {
3055 3057 if (f->is_java_frame()) {
3056 3058 javaVFrame* jvf = javaVFrame::cast(f);
3057 3059 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
3058 3060
3059 3061 // Print out lock information
3060 3062 if (JavaMonitorsInStackTrace) {
3061 3063 jvf->print_lock_info_on(st, count);
3062 3064 }
3063 3065 } else {
3064 3066 // Ignore non-Java frames
3065 3067 }
3066 3068
3067 3069 // Bail-out case for too deep stacks
3068 3070 count++;
3069 3071 if (MaxJavaStackTraceDepth == count) return;
3070 3072 }
3071 3073 }
3072 3074
3073 3075
3074 3076 // JVMTI PopFrame support
3075 3077 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
3076 3078 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
3077 3079 if (in_bytes(size_in_bytes) != 0) {
3078 3080 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
3079 3081 _popframe_preserved_args_size = in_bytes(size_in_bytes);
3080 3082 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
3081 3083 }
3082 3084 }
3083 3085
3084 3086 void* JavaThread::popframe_preserved_args() {
3085 3087 return _popframe_preserved_args;
3086 3088 }
3087 3089
3088 3090 ByteSize JavaThread::popframe_preserved_args_size() {
3089 3091 return in_ByteSize(_popframe_preserved_args_size);
3090 3092 }
3091 3093
3092 3094 WordSize JavaThread::popframe_preserved_args_size_in_words() {
3093 3095 int sz = in_bytes(popframe_preserved_args_size());
3094 3096 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
3095 3097 return in_WordSize(sz / wordSize);
3096 3098 }
3097 3099
3098 3100 void JavaThread::popframe_free_preserved_args() {
3099 3101 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
3100 3102 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread);
3101 3103 _popframe_preserved_args = NULL;
3102 3104 _popframe_preserved_args_size = 0;
3103 3105 }
3104 3106
3105 3107 #ifndef PRODUCT
3106 3108
3107 3109 void JavaThread::trace_frames() {
3108 3110 tty->print_cr("[Describe stack]");
3109 3111 int frame_no = 1;
3110 3112 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
3111 3113 tty->print(" %d. ", frame_no++);
3112 3114 fst.current()->print_value_on(tty,this);
3113 3115 tty->cr();
3114 3116 }
3115 3117 }
3116 3118
3117 3119 class PrintAndVerifyOopClosure: public OopClosure {
3118 3120 protected:
3119 3121 template <class T> inline void do_oop_work(T* p) {
3120 3122 oop obj = oopDesc::load_decode_heap_oop(p);
3121 3123 if (obj == NULL) return;
3122 3124 tty->print(INTPTR_FORMAT ": ", p);
3123 3125 if (obj->is_oop_or_null()) {
3124 3126 if (obj->is_objArray()) {
3125 3127 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
3126 3128 } else {
3127 3129 obj->print();
3128 3130 }
3129 3131 } else {
3130 3132 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
3131 3133 }
3132 3134 tty->cr();
3133 3135 }
3134 3136 public:
3135 3137 virtual void do_oop(oop* p) { do_oop_work(p); }
3136 3138 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
3137 3139 };
3138 3140
3139 3141
3140 3142 static void oops_print(frame* f, const RegisterMap *map) {
3141 3143 PrintAndVerifyOopClosure print;
3142 3144 f->print_value();
3143 3145 f->oops_do(&print, NULL, NULL, (RegisterMap*)map);
3144 3146 }
3145 3147
3146 3148 // Print our all the locations that contain oops and whether they are
3147 3149 // valid or not. This useful when trying to find the oldest frame
3148 3150 // where an oop has gone bad since the frame walk is from youngest to
3149 3151 // oldest.
3150 3152 void JavaThread::trace_oops() {
3151 3153 tty->print_cr("[Trace oops]");
3152 3154 frames_do(oops_print);
3153 3155 }
3154 3156
3155 3157
3156 3158 #ifdef ASSERT
3157 3159 // Print or validate the layout of stack frames
3158 3160 void JavaThread::print_frame_layout(int depth, bool validate_only) {
3159 3161 ResourceMark rm;
3160 3162 PRESERVE_EXCEPTION_MARK;
3161 3163 FrameValues values;
3162 3164 int frame_no = 0;
3163 3165 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
3164 3166 fst.current()->describe(values, ++frame_no);
3165 3167 if (depth == frame_no) break;
3166 3168 }
3167 3169 if (validate_only) {
3168 3170 values.validate();
3169 3171 } else {
3170 3172 tty->print_cr("[Describe stack layout]");
3171 3173 values.print(this);
3172 3174 }
3173 3175 }
3174 3176 #endif
3175 3177
3176 3178 void JavaThread::trace_stack_from(vframe* start_vf) {
3177 3179 ResourceMark rm;
3178 3180 int vframe_no = 1;
3179 3181 for (vframe* f = start_vf; f; f = f->sender() ) {
3180 3182 if (f->is_java_frame()) {
3181 3183 javaVFrame::cast(f)->print_activation(vframe_no++);
3182 3184 } else {
3183 3185 f->print();
3184 3186 }
3185 3187 if (vframe_no > StackPrintLimit) {
3186 3188 tty->print_cr("...<more frames>...");
3187 3189 return;
3188 3190 }
3189 3191 }
3190 3192 }
3191 3193
3192 3194
3193 3195 void JavaThread::trace_stack() {
3194 3196 if (!has_last_Java_frame()) return;
3195 3197 ResourceMark rm;
3196 3198 HandleMark hm;
3197 3199 RegisterMap reg_map(this);
3198 3200 trace_stack_from(last_java_vframe(®_map));
3199 3201 }
3200 3202
3201 3203
3202 3204 #endif // PRODUCT
3203 3205
3204 3206
3205 3207 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
3206 3208 assert(reg_map != NULL, "a map must be given");
3207 3209 frame f = last_frame();
3208 3210 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
3209 3211 if (vf->is_java_frame()) return javaVFrame::cast(vf);
3210 3212 }
3211 3213 return NULL;
3212 3214 }
3213 3215
3214 3216
3215 3217 Klass* JavaThread::security_get_caller_class(int depth) {
3216 3218 vframeStream vfst(this);
3217 3219 vfst.security_get_caller_frame(depth);
3218 3220 if (!vfst.at_end()) {
3219 3221 return vfst.method()->method_holder();
3220 3222 }
3221 3223 return NULL;
3222 3224 }
3223 3225
3224 3226 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
3225 3227 assert(thread->is_Compiler_thread(), "must be compiler thread");
3226 3228 CompileBroker::compiler_thread_loop();
3227 3229 }
3228 3230
3229 3231 // Create a CompilerThread
3230 3232 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
3231 3233 : JavaThread(&compiler_thread_entry) {
3232 3234 _env = NULL;
3233 3235 _log = NULL;
3234 3236 _task = NULL;
3235 3237 _queue = queue;
3236 3238 _counters = counters;
3237 3239 _buffer_blob = NULL;
3238 3240 _scanned_nmethod = NULL;
3239 3241 _compiler = NULL;
3240 3242
3241 3243 #ifndef PRODUCT
3242 3244 _ideal_graph_printer = NULL;
3243 3245 #endif
3244 3246 }
3245 3247
3246 3248 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
3247 3249 JavaThread::oops_do(f, cld_f, cf);
3248 3250 if (_scanned_nmethod != NULL && cf != NULL) {
3249 3251 // Safepoints can occur when the sweeper is scanning an nmethod so
3250 3252 // process it here to make sure it isn't unloaded in the middle of
3251 3253 // a scan.
3252 3254 cf->do_code_blob(_scanned_nmethod);
3253 3255 }
3254 3256 }
3255 3257
3256 3258
3257 3259 // ======= Threads ========
3258 3260
3259 3261 // The Threads class links together all active threads, and provides
3260 3262 // operations over all threads. It is protected by its own Mutex
3261 3263 // lock, which is also used in other contexts to protect thread
3262 3264 // operations from having the thread being operated on from exiting
3263 3265 // and going away unexpectedly (e.g., safepoint synchronization)
3264 3266
3265 3267 JavaThread* Threads::_thread_list = NULL;
3266 3268 int Threads::_number_of_threads = 0;
3267 3269 int Threads::_number_of_non_daemon_threads = 0;
3268 3270 int Threads::_return_code = 0;
3269 3271 size_t JavaThread::_stack_size_at_create = 0;
3270 3272 #ifdef ASSERT
3271 3273 bool Threads::_vm_complete = false;
3272 3274 #endif
3273 3275
3274 3276 // All JavaThreads
3275 3277 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3276 3278
3277 3279 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3278 3280 void Threads::threads_do(ThreadClosure* tc) {
3279 3281 assert_locked_or_safepoint(Threads_lock);
3280 3282 // ALL_JAVA_THREADS iterates through all JavaThreads
3281 3283 ALL_JAVA_THREADS(p) {
3282 3284 tc->do_thread(p);
3283 3285 }
3284 3286 // Someday we could have a table or list of all non-JavaThreads.
3285 3287 // For now, just manually iterate through them.
3286 3288 tc->do_thread(VMThread::vm_thread());
3287 3289 Universe::heap()->gc_threads_do(tc);
3288 3290 WatcherThread *wt = WatcherThread::watcher_thread();
3289 3291 // Strictly speaking, the following NULL check isn't sufficient to make sure
3290 3292 // the data for WatcherThread is still valid upon being examined. However,
3291 3293 // considering that WatchThread terminates when the VM is on the way to
3292 3294 // exit at safepoint, the chance of the above is extremely small. The right
3293 3295 // way to prevent termination of WatcherThread would be to acquire
3294 3296 // Terminator_lock, but we can't do that without violating the lock rank
3295 3297 // checking in some cases.
3296 3298 if (wt != NULL)
3297 3299 tc->do_thread(wt);
3298 3300
3299 3301 // If CompilerThreads ever become non-JavaThreads, add them here
3300 3302 }
3301 3303
3302 3304 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3303 3305
3304 3306 extern void JDK_Version_init();
3305 3307
3306 3308 // Check version
3307 3309 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3308 3310
3309 3311 // Initialize the output stream module
3310 3312 ostream_init();
3311 3313
3312 3314 // Process java launcher properties.
3313 3315 Arguments::process_sun_java_launcher_properties(args);
3314 3316
3315 3317 // Initialize the os module before using TLS
3316 3318 os::init();
3317 3319
3318 3320 // Initialize system properties.
3319 3321 Arguments::init_system_properties();
3320 3322
3321 3323 // So that JDK version can be used as a discrimintor when parsing arguments
3322 3324 JDK_Version_init();
3323 3325
3324 3326 // Update/Initialize System properties after JDK version number is known
3325 3327 Arguments::init_version_specific_system_properties();
3326 3328
3327 3329 // Parse arguments
3328 3330 jint parse_result = Arguments::parse(args);
3329 3331 if (parse_result != JNI_OK) return parse_result;
3330 3332
3331 3333 os::init_before_ergo();
3332 3334
3333 3335 jint ergo_result = Arguments::apply_ergo();
3334 3336 if (ergo_result != JNI_OK) return ergo_result;
3335 3337
3336 3338 if (PauseAtStartup) {
3337 3339 os::pause();
3338 3340 }
3339 3341
3340 3342 #ifndef USDT2
3341 3343 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3342 3344 #else /* USDT2 */
3343 3345 HOTSPOT_VM_INIT_BEGIN();
3344 3346 #endif /* USDT2 */
3345 3347
3346 3348 // Record VM creation timing statistics
3347 3349 TraceVmCreationTime create_vm_timer;
3348 3350 create_vm_timer.start();
3349 3351
3350 3352 // Timing (must come after argument parsing)
3351 3353 TraceTime timer("Create VM", TraceStartupTime);
3352 3354
3353 3355 // Initialize the os module after parsing the args
3354 3356 jint os_init_2_result = os::init_2();
3355 3357 if (os_init_2_result != JNI_OK) return os_init_2_result;
3356 3358
3357 3359 jint adjust_after_os_result = Arguments::adjust_after_os();
3358 3360 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
3359 3361
3360 3362 // intialize TLS
3361 3363 ThreadLocalStorage::init();
3362 3364
3363 3365 // Initialize output stream logging
3364 3366 ostream_init_log();
3365 3367
3366 3368 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3367 3369 // Must be before create_vm_init_agents()
3368 3370 if (Arguments::init_libraries_at_startup()) {
3369 3371 convert_vm_init_libraries_to_agents();
3370 3372 }
3371 3373
3372 3374 // Launch -agentlib/-agentpath and converted -Xrun agents
3373 3375 if (Arguments::init_agents_at_startup()) {
3374 3376 create_vm_init_agents();
3375 3377 }
3376 3378
3377 3379 // Initialize Threads state
3378 3380 _thread_list = NULL;
3379 3381 _number_of_threads = 0;
3380 3382 _number_of_non_daemon_threads = 0;
3381 3383
3382 3384 // Initialize global data structures and create system classes in heap
3383 3385 vm_init_globals();
3384 3386
3385 3387 // Attach the main thread to this os thread
3386 3388 JavaThread* main_thread = new JavaThread();
3387 3389 main_thread->set_thread_state(_thread_in_vm);
3388 3390 // must do this before set_active_handles and initialize_thread_local_storage
3389 3391 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3390 3392 // change the stack size recorded here to one based on the java thread
3391 3393 // stacksize. This adjusted size is what is used to figure the placement
3392 3394 // of the guard pages.
3393 3395 main_thread->record_stack_base_and_size();
3394 3396 main_thread->initialize_thread_local_storage();
3395 3397
3396 3398 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3397 3399
3398 3400 if (!main_thread->set_as_starting_thread()) {
3399 3401 vm_shutdown_during_initialization(
3400 3402 "Failed necessary internal allocation. Out of swap space");
3401 3403 delete main_thread;
3402 3404 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3403 3405 return JNI_ENOMEM;
3404 3406 }
3405 3407
3406 3408 // Enable guard page *after* os::create_main_thread(), otherwise it would
3407 3409 // crash Linux VM, see notes in os_linux.cpp.
3408 3410 main_thread->create_stack_guard_pages();
3409 3411
3410 3412 // Initialize Java-Level synchronization subsystem
3411 3413 ObjectMonitor::Initialize() ;
3412 3414
3413 3415 // Initialize global modules
3414 3416 jint status = init_globals();
3415 3417 if (status != JNI_OK) {
3416 3418 delete main_thread;
3417 3419 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3418 3420 return status;
3419 3421 }
3420 3422
3421 3423 // Should be done after the heap is fully created
3422 3424 main_thread->cache_global_variables();
3423 3425
3424 3426 HandleMark hm;
3425 3427
3426 3428 { MutexLocker mu(Threads_lock);
3427 3429 Threads::add(main_thread);
3428 3430 }
3429 3431
3430 3432 // Any JVMTI raw monitors entered in onload will transition into
3431 3433 // real raw monitor. VM is setup enough here for raw monitor enter.
3432 3434 JvmtiExport::transition_pending_onload_raw_monitors();
3433 3435
3434 3436 // Create the VMThread
3435 3437 { TraceTime timer("Start VMThread", TraceStartupTime);
3436 3438 VMThread::create();
3437 3439 Thread* vmthread = VMThread::vm_thread();
3438 3440
3439 3441 if (!os::create_thread(vmthread, os::vm_thread))
3440 3442 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3441 3443
3442 3444 // Wait for the VM thread to become ready, and VMThread::run to initialize
3443 3445 // Monitors can have spurious returns, must always check another state flag
3444 3446 {
3445 3447 MutexLocker ml(Notify_lock);
3446 3448 os::start_thread(vmthread);
3447 3449 while (vmthread->active_handles() == NULL) {
3448 3450 Notify_lock->wait();
3449 3451 }
3450 3452 }
3451 3453 }
3452 3454
3453 3455 assert (Universe::is_fully_initialized(), "not initialized");
3454 3456 if (VerifyDuringStartup) {
3455 3457 // Make sure we're starting with a clean slate.
3456 3458 VM_Verify verify_op;
3457 3459 VMThread::execute(&verify_op);
3458 3460 }
3459 3461
3460 3462 EXCEPTION_MARK;
3461 3463
3462 3464 // At this point, the Universe is initialized, but we have not executed
3463 3465 // any byte code. Now is a good time (the only time) to dump out the
3464 3466 // internal state of the JVM for sharing.
3465 3467 if (DumpSharedSpaces) {
3466 3468 MetaspaceShared::preload_and_dump(CHECK_0);
3467 3469 ShouldNotReachHere();
3468 3470 }
3469 3471
3470 3472 // Always call even when there are not JVMTI environments yet, since environments
3471 3473 // may be attached late and JVMTI must track phases of VM execution
3472 3474 JvmtiExport::enter_start_phase();
3473 3475
3474 3476 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3475 3477 JvmtiExport::post_vm_start();
3476 3478
3477 3479 {
3478 3480 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3479 3481
3480 3482 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3481 3483 create_vm_init_libraries();
3482 3484 }
3483 3485
3484 3486 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3485 3487
3486 3488 // Initialize java_lang.System (needed before creating the thread)
3487 3489 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3488 3490 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3489 3491 Handle thread_group = create_initial_thread_group(CHECK_0);
3490 3492 Universe::set_main_thread_group(thread_group());
3491 3493 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3492 3494 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3493 3495 main_thread->set_threadObj(thread_object);
3494 3496 // Set thread status to running since main thread has
3495 3497 // been started and running.
3496 3498 java_lang_Thread::set_thread_status(thread_object,
3497 3499 java_lang_Thread::RUNNABLE);
3498 3500
3499 3501 // The VM creates & returns objects of this class. Make sure it's initialized.
3500 3502 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3501 3503
3502 3504 // The VM preresolves methods to these classes. Make sure that they get initialized
3503 3505 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3504 3506 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3505 3507 call_initializeSystemClass(CHECK_0);
3506 3508
3507 3509 // get the Java runtime name after java.lang.System is initialized
3508 3510 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
3509 3511 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
3510 3512
3511 3513 // an instance of OutOfMemory exception has been allocated earlier
3512 3514 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3513 3515 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3514 3516 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3515 3517 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3516 3518 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3517 3519 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3518 3520 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3519 3521 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0);
3520 3522 }
3521 3523
3522 3524 // See : bugid 4211085.
3523 3525 // Background : the static initializer of java.lang.Compiler tries to read
3524 3526 // property"java.compiler" and read & write property "java.vm.info".
3525 3527 // When a security manager is installed through the command line
3526 3528 // option "-Djava.security.manager", the above properties are not
3527 3529 // readable and the static initializer for java.lang.Compiler fails
3528 3530 // resulting in a NoClassDefFoundError. This can happen in any
3529 3531 // user code which calls methods in java.lang.Compiler.
3530 3532 // Hack : the hack is to pre-load and initialize this class, so that only
3531 3533 // system domains are on the stack when the properties are read.
3532 3534 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3533 3535 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3534 3536 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3535 3537 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3536 3538 // Once that is done, we should remove this hack.
3537 3539 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3538 3540
3539 3541 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3540 3542 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3541 3543 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3542 3544 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3543 3545 // This should also be taken out as soon as 4211383 gets fixed.
3544 3546 reset_vm_info_property(CHECK_0);
3545 3547
3546 3548 quicken_jni_functions();
3547 3549
3548 3550 // Must be run after init_ft which initializes ft_enabled
3549 3551 if (TRACE_INITIALIZE() != JNI_OK) {
3550 3552 vm_exit_during_initialization("Failed to initialize tracing backend");
3551 3553 }
3552 3554
3553 3555 // Set flag that basic initialization has completed. Used by exceptions and various
3554 3556 // debug stuff, that does not work until all basic classes have been initialized.
3555 3557 set_init_completed();
3556 3558
3557 3559 Metaspace::post_initialize();
3558 3560
3559 3561 #ifndef USDT2
3560 3562 HS_DTRACE_PROBE(hotspot, vm__init__end);
3561 3563 #else /* USDT2 */
3562 3564 HOTSPOT_VM_INIT_END();
3563 3565 #endif /* USDT2 */
3564 3566
3565 3567 // record VM initialization completion time
3566 3568 #if INCLUDE_MANAGEMENT
3567 3569 Management::record_vm_init_completed();
3568 3570 #endif // INCLUDE_MANAGEMENT
3569 3571
3570 3572 // Compute system loader. Note that this has to occur after set_init_completed, since
3571 3573 // valid exceptions may be thrown in the process.
3572 3574 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3573 3575 // set_init_completed has just been called, causing exceptions not to be shortcut
3574 3576 // anymore. We call vm_exit_during_initialization directly instead.
3575 3577 SystemDictionary::compute_java_system_loader(THREAD);
3576 3578 if (HAS_PENDING_EXCEPTION) {
3577 3579 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3578 3580 }
3579 3581
3580 3582 #if INCLUDE_ALL_GCS
3581 3583 // Support for ConcurrentMarkSweep. This should be cleaned up
3582 3584 // and better encapsulated. The ugly nested if test would go away
3583 3585 // once things are properly refactored. XXX YSR
3584 3586 if (UseConcMarkSweepGC || UseG1GC) {
3585 3587 if (UseConcMarkSweepGC) {
3586 3588 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3587 3589 } else {
3588 3590 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3589 3591 }
3590 3592 if (HAS_PENDING_EXCEPTION) {
3591 3593 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3592 3594 }
3593 3595 }
3594 3596 #endif // INCLUDE_ALL_GCS
3595 3597
3596 3598 // Always call even when there are not JVMTI environments yet, since environments
3597 3599 // may be attached late and JVMTI must track phases of VM execution
3598 3600 JvmtiExport::enter_live_phase();
3599 3601
3600 3602 // Signal Dispatcher needs to be started before VMInit event is posted
3601 3603 os::signal_init();
3602 3604
3603 3605 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3604 3606 if (!DisableAttachMechanism) {
3605 3607 AttachListener::vm_start();
3606 3608 if (StartAttachListener || AttachListener::init_at_startup()) {
3607 3609 AttachListener::init();
3608 3610 }
3609 3611 }
3610 3612
3611 3613 // Launch -Xrun agents
3612 3614 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3613 3615 // back-end can launch with -Xdebug -Xrunjdwp.
3614 3616 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3615 3617 create_vm_init_libraries();
3616 3618 }
3617 3619
3618 3620 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3619 3621 JvmtiExport::post_vm_initialized();
3620 3622
3621 3623 if (TRACE_START() != JNI_OK) {
3622 3624 vm_exit_during_initialization("Failed to start tracing backend.");
3623 3625 }
3624 3626
3625 3627 if (CleanChunkPoolAsync) {
3626 3628 Chunk::start_chunk_pool_cleaner_task();
3627 3629 }
3628 3630
3629 3631 // initialize compiler(s)
3630 3632 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK)
3631 3633 CompileBroker::compilation_init();
3632 3634 #endif
3633 3635
3634 3636 if (EnableInvokeDynamic) {
3635 3637 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
3636 3638 // It is done after compilers are initialized, because otherwise compilations of
3637 3639 // signature polymorphic MH intrinsics can be missed
3638 3640 // (see SystemDictionary::find_method_handle_intrinsic).
3639 3641 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0);
3640 3642 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0);
3641 3643 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0);
3642 3644 }
3643 3645
3644 3646 #if INCLUDE_MANAGEMENT
3645 3647 Management::initialize(THREAD);
3646 3648 #endif // INCLUDE_MANAGEMENT
3647 3649
3648 3650 if (HAS_PENDING_EXCEPTION) {
3649 3651 // management agent fails to start possibly due to
3650 3652 // configuration problem and is responsible for printing
3651 3653 // stack trace if appropriate. Simply exit VM.
3652 3654 vm_exit(1);
3653 3655 }
3654 3656
3655 3657 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3656 3658 if (MemProfiling) MemProfiler::engage();
3657 3659 StatSampler::engage();
3658 3660 if (CheckJNICalls) JniPeriodicChecker::engage();
3659 3661
3660 3662 BiasedLocking::init();
3661 3663
3662 3664 #if INCLUDE_RTM_OPT
3663 3665 RTMLockingCounters::init();
3664 3666 #endif
3665 3667
3666 3668 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3667 3669 call_postVMInitHook(THREAD);
3668 3670 // The Java side of PostVMInitHook.run must deal with all
3669 3671 // exceptions and provide means of diagnosis.
3670 3672 if (HAS_PENDING_EXCEPTION) {
3671 3673 CLEAR_PENDING_EXCEPTION;
3672 3674 }
3673 3675 }
3674 3676
3675 3677 {
3676 3678 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
3677 3679 // Make sure the watcher thread can be started by WatcherThread::start()
3678 3680 // or by dynamic enrollment.
3679 3681 WatcherThread::make_startable();
3680 3682 // Start up the WatcherThread if there are any periodic tasks
3681 3683 // NOTE: All PeriodicTasks should be registered by now. If they
3682 3684 // aren't, late joiners might appear to start slowly (we might
3683 3685 // take a while to process their first tick).
3684 3686 if (PeriodicTask::num_tasks() > 0) {
3685 3687 WatcherThread::start();
3686 3688 }
3687 3689 }
3688 3690
3689 3691 // Give os specific code one last chance to start
3690 3692 os::init_3();
3691 3693
3692 3694 create_vm_timer.end();
3693 3695 #ifdef ASSERT
3694 3696 _vm_complete = true;
3695 3697 #endif
3696 3698 return JNI_OK;
3697 3699 }
3698 3700
3699 3701 // type for the Agent_OnLoad and JVM_OnLoad entry points
3700 3702 extern "C" {
3701 3703 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3702 3704 }
3703 3705 // Find a command line agent library and return its entry point for
3704 3706 // -agentlib: -agentpath: -Xrun
3705 3707 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3706 3708 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3707 3709 OnLoadEntry_t on_load_entry = NULL;
3708 3710 void *library = NULL;
3709 3711
3710 3712 if (!agent->valid()) {
3711 3713 char buffer[JVM_MAXPATHLEN];
3712 3714 char ebuf[1024];
3713 3715 const char *name = agent->name();
3714 3716 const char *msg = "Could not find agent library ";
3715 3717
3716 3718 // First check to see if agent is statically linked into executable
3717 3719 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
3718 3720 library = agent->os_lib();
3719 3721 } else if (agent->is_absolute_path()) {
3720 3722 library = os::dll_load(name, ebuf, sizeof ebuf);
3721 3723 if (library == NULL) {
3722 3724 const char *sub_msg = " in absolute path, with error: ";
3723 3725 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3724 3726 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3725 3727 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3726 3728 // If we can't find the agent, exit.
3727 3729 vm_exit_during_initialization(buf, NULL);
3728 3730 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3729 3731 }
3730 3732 } else {
3731 3733 // Try to load the agent from the standard dll directory
3732 3734 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(),
3733 3735 name)) {
3734 3736 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3735 3737 }
3736 3738 if (library == NULL) { // Try the local directory
3737 3739 char ns[1] = {0};
3738 3740 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) {
3739 3741 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3740 3742 }
3741 3743 if (library == NULL) {
3742 3744 const char *sub_msg = " on the library path, with error: ";
3743 3745 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3744 3746 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
3745 3747 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3746 3748 // If we can't find the agent, exit.
3747 3749 vm_exit_during_initialization(buf, NULL);
3748 3750 FREE_C_HEAP_ARRAY(char, buf, mtThread);
3749 3751 }
3750 3752 }
3751 3753 }
3752 3754 agent->set_os_lib(library);
3753 3755 agent->set_valid();
3754 3756 }
3755 3757
3756 3758 // Find the OnLoad function.
3757 3759 on_load_entry =
3758 3760 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
3759 3761 false,
3760 3762 on_load_symbols,
3761 3763 num_symbol_entries));
3762 3764 return on_load_entry;
3763 3765 }
3764 3766
3765 3767 // Find the JVM_OnLoad entry point
3766 3768 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3767 3769 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3768 3770 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3769 3771 }
3770 3772
3771 3773 // Find the Agent_OnLoad entry point
3772 3774 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3773 3775 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3774 3776 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3775 3777 }
3776 3778
3777 3779 // For backwards compatibility with -Xrun
3778 3780 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3779 3781 // treated like -agentpath:
3780 3782 // Must be called before agent libraries are created
3781 3783 void Threads::convert_vm_init_libraries_to_agents() {
3782 3784 AgentLibrary* agent;
3783 3785 AgentLibrary* next;
3784 3786
3785 3787 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3786 3788 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3787 3789 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3788 3790
3789 3791 // If there is an JVM_OnLoad function it will get called later,
3790 3792 // otherwise see if there is an Agent_OnLoad
3791 3793 if (on_load_entry == NULL) {
3792 3794 on_load_entry = lookup_agent_on_load(agent);
3793 3795 if (on_load_entry != NULL) {
3794 3796 // switch it to the agent list -- so that Agent_OnLoad will be called,
3795 3797 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3796 3798 Arguments::convert_library_to_agent(agent);
3797 3799 } else {
3798 3800 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3799 3801 }
3800 3802 }
3801 3803 }
3802 3804 }
3803 3805
3804 3806 // Create agents for -agentlib: -agentpath: and converted -Xrun
3805 3807 // Invokes Agent_OnLoad
3806 3808 // Called very early -- before JavaThreads exist
3807 3809 void Threads::create_vm_init_agents() {
3808 3810 extern struct JavaVM_ main_vm;
3809 3811 AgentLibrary* agent;
3810 3812
3811 3813 JvmtiExport::enter_onload_phase();
3812 3814
3813 3815 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3814 3816 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3815 3817
3816 3818 if (on_load_entry != NULL) {
3817 3819 // Invoke the Agent_OnLoad function
3818 3820 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3819 3821 if (err != JNI_OK) {
3820 3822 vm_exit_during_initialization("agent library failed to init", agent->name());
3821 3823 }
3822 3824 } else {
3823 3825 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3824 3826 }
3825 3827 }
3826 3828 JvmtiExport::enter_primordial_phase();
3827 3829 }
3828 3830
3829 3831 extern "C" {
3830 3832 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3831 3833 }
3832 3834
3833 3835 void Threads::shutdown_vm_agents() {
3834 3836 // Send any Agent_OnUnload notifications
3835 3837 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3836 3838 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
3837 3839 extern struct JavaVM_ main_vm;
3838 3840 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3839 3841
3840 3842 // Find the Agent_OnUnload function.
3841 3843 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3842 3844 os::find_agent_function(agent,
3843 3845 false,
3844 3846 on_unload_symbols,
3845 3847 num_symbol_entries));
3846 3848
3847 3849 // Invoke the Agent_OnUnload function
3848 3850 if (unload_entry != NULL) {
3849 3851 JavaThread* thread = JavaThread::current();
3850 3852 ThreadToNativeFromVM ttn(thread);
3851 3853 HandleMark hm(thread);
3852 3854 (*unload_entry)(&main_vm);
3853 3855 }
3854 3856 }
3855 3857 }
3856 3858
3857 3859 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3858 3860 // Invokes JVM_OnLoad
3859 3861 void Threads::create_vm_init_libraries() {
3860 3862 extern struct JavaVM_ main_vm;
3861 3863 AgentLibrary* agent;
3862 3864
3863 3865 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3864 3866 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3865 3867
3866 3868 if (on_load_entry != NULL) {
3867 3869 // Invoke the JVM_OnLoad function
3868 3870 JavaThread* thread = JavaThread::current();
3869 3871 ThreadToNativeFromVM ttn(thread);
3870 3872 HandleMark hm(thread);
3871 3873 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3872 3874 if (err != JNI_OK) {
3873 3875 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3874 3876 }
3875 3877 } else {
3876 3878 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3877 3879 }
3878 3880 }
3879 3881 }
3880 3882
3881 3883 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
3882 3884 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
3883 3885
3884 3886 JavaThread* java_thread = NULL;
3885 3887 // Sequential search for now. Need to do better optimization later.
3886 3888 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
3887 3889 oop tobj = thread->threadObj();
3888 3890 if (!thread->is_exiting() &&
3889 3891 tobj != NULL &&
3890 3892 java_tid == java_lang_Thread::thread_id(tobj)) {
3891 3893 java_thread = thread;
3892 3894 break;
3893 3895 }
3894 3896 }
3895 3897 return java_thread;
3896 3898 }
3897 3899
3898 3900
3899 3901 // Last thread running calls java.lang.Shutdown.shutdown()
3900 3902 void JavaThread::invoke_shutdown_hooks() {
3901 3903 HandleMark hm(this);
3902 3904
3903 3905 // We could get here with a pending exception, if so clear it now.
3904 3906 if (this->has_pending_exception()) {
3905 3907 this->clear_pending_exception();
3906 3908 }
3907 3909
3908 3910 EXCEPTION_MARK;
3909 3911 Klass* k =
3910 3912 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3911 3913 THREAD);
3912 3914 if (k != NULL) {
3913 3915 // SystemDictionary::resolve_or_null will return null if there was
3914 3916 // an exception. If we cannot load the Shutdown class, just don't
3915 3917 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3916 3918 // and finalizers (if runFinalizersOnExit is set) won't be run.
3917 3919 // Note that if a shutdown hook was registered or runFinalizersOnExit
3918 3920 // was called, the Shutdown class would have already been loaded
3919 3921 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3920 3922 instanceKlassHandle shutdown_klass (THREAD, k);
3921 3923 JavaValue result(T_VOID);
3922 3924 JavaCalls::call_static(&result,
3923 3925 shutdown_klass,
3924 3926 vmSymbols::shutdown_method_name(),
3925 3927 vmSymbols::void_method_signature(),
3926 3928 THREAD);
3927 3929 }
3928 3930 CLEAR_PENDING_EXCEPTION;
3929 3931 }
3930 3932
3931 3933 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3932 3934 // the program falls off the end of main(). Another VM exit path is through
3933 3935 // vm_exit() when the program calls System.exit() to return a value or when
3934 3936 // there is a serious error in VM. The two shutdown paths are not exactly
3935 3937 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3936 3938 // and VM_Exit op at VM level.
3937 3939 //
3938 3940 // Shutdown sequence:
3939 3941 // + Shutdown native memory tracking if it is on
3940 3942 // + Wait until we are the last non-daemon thread to execute
3941 3943 // <-- every thing is still working at this moment -->
3942 3944 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3943 3945 // shutdown hooks, run finalizers if finalization-on-exit
3944 3946 // + Call before_exit(), prepare for VM exit
3945 3947 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3946 3948 // currently the only user of this mechanism is File.deleteOnExit())
3947 3949 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3948 3950 // post thread end and vm death events to JVMTI,
3949 3951 // stop signal thread
3950 3952 // + Call JavaThread::exit(), it will:
3951 3953 // > release JNI handle blocks, remove stack guard pages
3952 3954 // > remove this thread from Threads list
3953 3955 // <-- no more Java code from this thread after this point -->
3954 3956 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3955 3957 // the compiler threads at safepoint
3956 3958 // <-- do not use anything that could get blocked by Safepoint -->
3957 3959 // + Disable tracing at JNI/JVM barriers
3958 3960 // + Set _vm_exited flag for threads that are still running native code
3959 3961 // + Delete this thread
3960 3962 // + Call exit_globals()
3961 3963 // > deletes tty
3962 3964 // > deletes PerfMemory resources
3963 3965 // + Return to caller
3964 3966
3965 3967 bool Threads::destroy_vm() {
3966 3968 JavaThread* thread = JavaThread::current();
3967 3969
3968 3970 #ifdef ASSERT
3969 3971 _vm_complete = false;
3970 3972 #endif
3971 3973 // Wait until we are the last non-daemon thread to execute
3972 3974 { MutexLocker nu(Threads_lock);
3973 3975 while (Threads::number_of_non_daemon_threads() > 1 )
3974 3976 // This wait should make safepoint checks, wait without a timeout,
3975 3977 // and wait as a suspend-equivalent condition.
3976 3978 //
3977 3979 // Note: If the FlatProfiler is running and this thread is waiting
3978 3980 // for another non-daemon thread to finish, then the FlatProfiler
3979 3981 // is waiting for the external suspend request on this thread to
3980 3982 // complete. wait_for_ext_suspend_completion() will eventually
3981 3983 // timeout, but that takes time. Making this wait a suspend-
3982 3984 // equivalent condition solves that timeout problem.
3983 3985 //
3984 3986 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3985 3987 Mutex::_as_suspend_equivalent_flag);
3986 3988 }
3987 3989
3988 3990 // Hang forever on exit if we are reporting an error.
3989 3991 if (ShowMessageBoxOnError && is_error_reported()) {
3990 3992 os::infinite_sleep();
3991 3993 }
3992 3994 os::wait_for_keypress_at_exit();
3993 3995
3994 3996 if (JDK_Version::is_jdk12x_version()) {
3995 3997 // We are the last thread running, so check if finalizers should be run.
3996 3998 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3997 3999 HandleMark rm(thread);
3998 4000 Universe::run_finalizers_on_exit();
3999 4001 } else {
4000 4002 // run Java level shutdown hooks
4001 4003 thread->invoke_shutdown_hooks();
4002 4004 }
4003 4005
4004 4006 before_exit(thread);
4005 4007
4006 4008 thread->exit(true);
4007 4009
4008 4010 // Stop VM thread.
4009 4011 {
4010 4012 // 4945125 The vm thread comes to a safepoint during exit.
4011 4013 // GC vm_operations can get caught at the safepoint, and the
4012 4014 // heap is unparseable if they are caught. Grab the Heap_lock
4013 4015 // to prevent this. The GC vm_operations will not be able to
4014 4016 // queue until after the vm thread is dead. After this point,
4015 4017 // we'll never emerge out of the safepoint before the VM exits.
4016 4018
4017 4019 MutexLocker ml(Heap_lock);
4018 4020
4019 4021 VMThread::wait_for_vm_thread_exit();
4020 4022 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
4021 4023 VMThread::destroy();
4022 4024 }
4023 4025
4024 4026 // clean up ideal graph printers
4025 4027 #if defined(COMPILER2) && !defined(PRODUCT)
4026 4028 IdealGraphPrinter::clean_up();
4027 4029 #endif
4028 4030
4029 4031 // Now, all Java threads are gone except daemon threads. Daemon threads
4030 4032 // running Java code or in VM are stopped by the Safepoint. However,
4031 4033 // daemon threads executing native code are still running. But they
4032 4034 // will be stopped at native=>Java/VM barriers. Note that we can't
4033 4035 // simply kill or suspend them, as it is inherently deadlock-prone.
4034 4036
4035 4037 #ifndef PRODUCT
4036 4038 // disable function tracing at JNI/JVM barriers
4037 4039 TraceJNICalls = false;
4038 4040 TraceJVMCalls = false;
4039 4041 TraceRuntimeCalls = false;
4040 4042 #endif
4041 4043
4042 4044 VM_Exit::set_vm_exited();
4043 4045
4044 4046 notify_vm_shutdown();
4045 4047
4046 4048 delete thread;
4047 4049
4048 4050 // exit_globals() will delete tty
4049 4051 exit_globals();
4050 4052
4051 4053 return true;
4052 4054 }
4053 4055
4054 4056
4055 4057 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
4056 4058 if (version == JNI_VERSION_1_1) return JNI_TRUE;
4057 4059 return is_supported_jni_version(version);
4058 4060 }
4059 4061
4060 4062
4061 4063 jboolean Threads::is_supported_jni_version(jint version) {
4062 4064 if (version == JNI_VERSION_1_2) return JNI_TRUE;
4063 4065 if (version == JNI_VERSION_1_4) return JNI_TRUE;
4064 4066 if (version == JNI_VERSION_1_6) return JNI_TRUE;
4065 4067 if (version == JNI_VERSION_1_8) return JNI_TRUE;
4066 4068 return JNI_FALSE;
4067 4069 }
4068 4070
4069 4071
4070 4072 void Threads::add(JavaThread* p, bool force_daemon) {
4071 4073 // The threads lock must be owned at this point
4072 4074 assert_locked_or_safepoint(Threads_lock);
4073 4075
4074 4076 // See the comment for this method in thread.hpp for its purpose and
4075 4077 // why it is called here.
4076 4078 p->initialize_queues();
4077 4079 p->set_next(_thread_list);
4078 4080 _thread_list = p;
4079 4081 _number_of_threads++;
4080 4082 oop threadObj = p->threadObj();
4081 4083 bool daemon = true;
4082 4084 // Bootstrapping problem: threadObj can be null for initial
4083 4085 // JavaThread (or for threads attached via JNI)
4084 4086 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
4085 4087 _number_of_non_daemon_threads++;
4086 4088 daemon = false;
4087 4089 }
4088 4090
4089 4091 ThreadService::add_thread(p, daemon);
4090 4092
4091 4093 // Possible GC point.
4092 4094 Events::log(p, "Thread added: " INTPTR_FORMAT, p);
4093 4095 }
4094 4096
4095 4097 void Threads::remove(JavaThread* p) {
4096 4098 // Extra scope needed for Thread_lock, so we can check
4097 4099 // that we do not remove thread without safepoint code notice
4098 4100 { MutexLocker ml(Threads_lock);
4099 4101
4100 4102 assert(includes(p), "p must be present");
4101 4103
4102 4104 JavaThread* current = _thread_list;
4103 4105 JavaThread* prev = NULL;
4104 4106
4105 4107 while (current != p) {
4106 4108 prev = current;
4107 4109 current = current->next();
4108 4110 }
4109 4111
4110 4112 if (prev) {
4111 4113 prev->set_next(current->next());
4112 4114 } else {
4113 4115 _thread_list = p->next();
4114 4116 }
4115 4117 _number_of_threads--;
4116 4118 oop threadObj = p->threadObj();
4117 4119 bool daemon = true;
4118 4120 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
4119 4121 _number_of_non_daemon_threads--;
4120 4122 daemon = false;
4121 4123
4122 4124 // Only one thread left, do a notify on the Threads_lock so a thread waiting
4123 4125 // on destroy_vm will wake up.
4124 4126 if (number_of_non_daemon_threads() == 1)
4125 4127 Threads_lock->notify_all();
4126 4128 }
4127 4129 ThreadService::remove_thread(p, daemon);
4128 4130
4129 4131 // Make sure that safepoint code disregard this thread. This is needed since
4130 4132 // the thread might mess around with locks after this point. This can cause it
4131 4133 // to do callbacks into the safepoint code. However, the safepoint code is not aware
4132 4134 // of this thread since it is removed from the queue.
4133 4135 p->set_terminated_value();
4134 4136 } // unlock Threads_lock
4135 4137
4136 4138 // Since Events::log uses a lock, we grab it outside the Threads_lock
4137 4139 Events::log(p, "Thread exited: " INTPTR_FORMAT, p);
4138 4140 }
4139 4141
4140 4142 // Threads_lock must be held when this is called (or must be called during a safepoint)
4141 4143 bool Threads::includes(JavaThread* p) {
4142 4144 assert(Threads_lock->is_locked(), "sanity check");
4143 4145 ALL_JAVA_THREADS(q) {
4144 4146 if (q == p ) {
4145 4147 return true;
4146 4148 }
4147 4149 }
4148 4150 return false;
4149 4151 }
4150 4152
4151 4153 // Operations on the Threads list for GC. These are not explicitly locked,
4152 4154 // but the garbage collector must provide a safe context for them to run.
4153 4155 // In particular, these things should never be called when the Threads_lock
4154 4156 // is held by some other thread. (Note: the Safepoint abstraction also
4155 4157 // uses the Threads_lock to gurantee this property. It also makes sure that
4156 4158 // all threads gets blocked when exiting or starting).
4157 4159
4158 4160 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4159 4161 ALL_JAVA_THREADS(p) {
4160 4162 p->oops_do(f, cld_f, cf);
4161 4163 }
4162 4164 VMThread::vm_thread()->oops_do(f, cld_f, cf);
4163 4165 }
4164 4166
4165 4167 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) {
4166 4168 // Introduce a mechanism allowing parallel threads to claim threads as
4167 4169 // root groups. Overhead should be small enough to use all the time,
4168 4170 // even in sequential code.
4169 4171 SharedHeap* sh = SharedHeap::heap();
4170 4172 // Cannot yet substitute active_workers for n_par_threads
4171 4173 // because of G1CollectedHeap::verify() use of
4172 4174 // SharedHeap::process_roots(). n_par_threads == 0 will
4173 4175 // turn off parallelism in process_roots while active_workers
4174 4176 // is being used for parallelism elsewhere.
4175 4177 bool is_par = sh->n_par_threads() > 0;
4176 4178 assert(!is_par ||
4177 4179 (SharedHeap::heap()->n_par_threads() ==
4178 4180 SharedHeap::heap()->workers()->active_workers()), "Mismatch");
4179 4181 int cp = SharedHeap::heap()->strong_roots_parity();
4180 4182 ALL_JAVA_THREADS(p) {
4181 4183 if (p->claim_oops_do(is_par, cp)) {
4182 4184 p->oops_do(f, cld_f, cf);
4183 4185 }
4184 4186 }
4185 4187 VMThread* vmt = VMThread::vm_thread();
4186 4188 if (vmt->claim_oops_do(is_par, cp)) {
4187 4189 vmt->oops_do(f, cld_f, cf);
4188 4190 }
4189 4191 }
4190 4192
4191 4193 #if INCLUDE_ALL_GCS
4192 4194 // Used by ParallelScavenge
4193 4195 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
4194 4196 ALL_JAVA_THREADS(p) {
4195 4197 q->enqueue(new ThreadRootsTask(p));
4196 4198 }
4197 4199 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
4198 4200 }
4199 4201
4200 4202 // Used by Parallel Old
4201 4203 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
4202 4204 ALL_JAVA_THREADS(p) {
4203 4205 q->enqueue(new ThreadRootsMarkingTask(p));
4204 4206 }
4205 4207 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
4206 4208 }
4207 4209 #endif // INCLUDE_ALL_GCS
4208 4210
4209 4211 void Threads::nmethods_do(CodeBlobClosure* cf) {
4210 4212 ALL_JAVA_THREADS(p) {
4211 4213 p->nmethods_do(cf);
4212 4214 }
4213 4215 VMThread::vm_thread()->nmethods_do(cf);
4214 4216 }
4215 4217
4216 4218 void Threads::metadata_do(void f(Metadata*)) {
4217 4219 ALL_JAVA_THREADS(p) {
4218 4220 p->metadata_do(f);
4219 4221 }
4220 4222 }
4221 4223
4222 4224 void Threads::gc_epilogue() {
4223 4225 ALL_JAVA_THREADS(p) {
4224 4226 p->gc_epilogue();
4225 4227 }
4226 4228 }
4227 4229
4228 4230 void Threads::gc_prologue() {
4229 4231 ALL_JAVA_THREADS(p) {
4230 4232 p->gc_prologue();
4231 4233 }
4232 4234 }
4233 4235
4234 4236 void Threads::deoptimized_wrt_marked_nmethods() {
4235 4237 ALL_JAVA_THREADS(p) {
4236 4238 p->deoptimized_wrt_marked_nmethods();
4237 4239 }
4238 4240 }
4239 4241
4240 4242
4241 4243 // Get count Java threads that are waiting to enter the specified monitor.
4242 4244 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
4243 4245 address monitor, bool doLock) {
4244 4246 assert(doLock || SafepointSynchronize::is_at_safepoint(),
4245 4247 "must grab Threads_lock or be at safepoint");
4246 4248 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
4247 4249
4248 4250 int i = 0;
4249 4251 {
4250 4252 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4251 4253 ALL_JAVA_THREADS(p) {
4252 4254 if (p->is_Compiler_thread()) continue;
4253 4255
4254 4256 address pending = (address)p->current_pending_monitor();
4255 4257 if (pending == monitor) { // found a match
4256 4258 if (i < count) result->append(p); // save the first count matches
4257 4259 i++;
4258 4260 }
4259 4261 }
4260 4262 }
4261 4263 return result;
4262 4264 }
4263 4265
4264 4266
4265 4267 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
4266 4268 assert(doLock ||
4267 4269 Threads_lock->owned_by_self() ||
4268 4270 SafepointSynchronize::is_at_safepoint(),
4269 4271 "must grab Threads_lock or be at safepoint");
4270 4272
4271 4273 // NULL owner means not locked so we can skip the search
4272 4274 if (owner == NULL) return NULL;
4273 4275
4274 4276 {
4275 4277 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4276 4278 ALL_JAVA_THREADS(p) {
4277 4279 // first, see if owner is the address of a Java thread
4278 4280 if (owner == (address)p) return p;
4279 4281 }
4280 4282 }
4281 4283 // Cannot assert on lack of success here since this function may be
4282 4284 // used by code that is trying to report useful problem information
4283 4285 // like deadlock detection.
4284 4286 if (UseHeavyMonitors) return NULL;
4285 4287
4286 4288 //
4287 4289 // If we didn't find a matching Java thread and we didn't force use of
4288 4290 // heavyweight monitors, then the owner is the stack address of the
4289 4291 // Lock Word in the owning Java thread's stack.
4290 4292 //
4291 4293 JavaThread* the_owner = NULL;
4292 4294 {
4293 4295 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4294 4296 ALL_JAVA_THREADS(q) {
4295 4297 if (q->is_lock_owned(owner)) {
4296 4298 the_owner = q;
4297 4299 break;
4298 4300 }
4299 4301 }
4300 4302 }
4301 4303 // cannot assert on lack of success here; see above comment
4302 4304 return the_owner;
4303 4305 }
4304 4306
4305 4307 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4306 4308 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4307 4309 char buf[32];
4308 4310 st->print_cr("%s", os::local_time_string(buf, sizeof(buf)));
4309 4311
4310 4312 st->print_cr("Full thread dump %s (%s %s):",
4311 4313 Abstract_VM_Version::vm_name(),
4312 4314 Abstract_VM_Version::vm_release(),
4313 4315 Abstract_VM_Version::vm_info_string()
4314 4316 );
4315 4317 st->cr();
4316 4318
4317 4319 #if INCLUDE_ALL_GCS
4318 4320 // Dump concurrent locks
4319 4321 ConcurrentLocksDump concurrent_locks;
4320 4322 if (print_concurrent_locks) {
4321 4323 concurrent_locks.dump_at_safepoint();
4322 4324 }
4323 4325 #endif // INCLUDE_ALL_GCS
4324 4326
4325 4327 ALL_JAVA_THREADS(p) {
4326 4328 ResourceMark rm;
4327 4329 p->print_on(st);
4328 4330 if (print_stacks) {
4329 4331 if (internal_format) {
4330 4332 p->trace_stack();
4331 4333 } else {
4332 4334 p->print_stack_on(st);
4333 4335 }
4334 4336 }
4335 4337 st->cr();
4336 4338 #if INCLUDE_ALL_GCS
4337 4339 if (print_concurrent_locks) {
4338 4340 concurrent_locks.print_locks_on(p, st);
4339 4341 }
4340 4342 #endif // INCLUDE_ALL_GCS
4341 4343 }
4342 4344
4343 4345 VMThread::vm_thread()->print_on(st);
4344 4346 st->cr();
4345 4347 Universe::heap()->print_gc_threads_on(st);
4346 4348 WatcherThread* wt = WatcherThread::watcher_thread();
4347 4349 if (wt != NULL) {
4348 4350 wt->print_on(st);
4349 4351 st->cr();
4350 4352 }
4351 4353 CompileBroker::print_compiler_threads_on(st);
4352 4354 st->flush();
4353 4355 }
4354 4356
4355 4357 // Threads::print_on_error() is called by fatal error handler. It's possible
4356 4358 // that VM is not at safepoint and/or current thread is inside signal handler.
4357 4359 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4358 4360 // memory (even in resource area), it might deadlock the error handler.
4359 4361 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4360 4362 bool found_current = false;
4361 4363 st->print_cr("Java Threads: ( => current thread )");
4362 4364 ALL_JAVA_THREADS(thread) {
4363 4365 bool is_current = (current == thread);
4364 4366 found_current = found_current || is_current;
4365 4367
4366 4368 st->print("%s", is_current ? "=>" : " ");
4367 4369
4368 4370 st->print(PTR_FORMAT, thread);
4369 4371 st->print(" ");
4370 4372 thread->print_on_error(st, buf, buflen);
4371 4373 st->cr();
4372 4374 }
4373 4375 st->cr();
4374 4376
4375 4377 st->print_cr("Other Threads:");
4376 4378 if (VMThread::vm_thread()) {
4377 4379 bool is_current = (current == VMThread::vm_thread());
4378 4380 found_current = found_current || is_current;
4379 4381 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4380 4382
4381 4383 st->print(PTR_FORMAT, VMThread::vm_thread());
4382 4384 st->print(" ");
4383 4385 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4384 4386 st->cr();
4385 4387 }
4386 4388 WatcherThread* wt = WatcherThread::watcher_thread();
4387 4389 if (wt != NULL) {
4388 4390 bool is_current = (current == wt);
4389 4391 found_current = found_current || is_current;
4390 4392 st->print("%s", is_current ? "=>" : " ");
4391 4393
4392 4394 st->print(PTR_FORMAT, wt);
4393 4395 st->print(" ");
4394 4396 wt->print_on_error(st, buf, buflen);
4395 4397 st->cr();
4396 4398 }
4397 4399 if (!found_current) {
4398 4400 st->cr();
4399 4401 st->print("=>" PTR_FORMAT " (exited) ", current);
4400 4402 current->print_on_error(st, buf, buflen);
4401 4403 st->cr();
4402 4404 }
4403 4405 }
4404 4406
4405 4407 // Internal SpinLock and Mutex
4406 4408 // Based on ParkEvent
4407 4409
4408 4410 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4409 4411 //
4410 4412 // We employ SpinLocks _only for low-contention, fixed-length
4411 4413 // short-duration critical sections where we're concerned
4412 4414 // about native mutex_t or HotSpot Mutex:: latency.
4413 4415 // The mux construct provides a spin-then-block mutual exclusion
4414 4416 // mechanism.
4415 4417 //
4416 4418 // Testing has shown that contention on the ListLock guarding gFreeList
4417 4419 // is common. If we implement ListLock as a simple SpinLock it's common
4418 4420 // for the JVM to devolve to yielding with little progress. This is true
4419 4421 // despite the fact that the critical sections protected by ListLock are
4420 4422 // extremely short.
4421 4423 //
4422 4424 // TODO-FIXME: ListLock should be of type SpinLock.
4423 4425 // We should make this a 1st-class type, integrated into the lock
4424 4426 // hierarchy as leaf-locks. Critically, the SpinLock structure
4425 4427 // should have sufficient padding to avoid false-sharing and excessive
4426 4428 // cache-coherency traffic.
4427 4429
4428 4430
4429 4431 typedef volatile int SpinLockT ;
4430 4432
4431 4433 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4432 4434 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4433 4435 return ; // normal fast-path return
4434 4436 }
4435 4437
4436 4438 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4437 4439 TEVENT (SpinAcquire - ctx) ;
4438 4440 int ctr = 0 ;
4439 4441 int Yields = 0 ;
4440 4442 for (;;) {
4441 4443 while (*adr != 0) {
4442 4444 ++ctr ;
4443 4445 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4444 4446 if (Yields > 5) {
4445 4447 os::naked_short_sleep(1);
4446 4448 } else {
4447 4449 os::NakedYield() ;
4448 4450 ++Yields ;
4449 4451 }
4450 4452 } else {
4451 4453 SpinPause() ;
4452 4454 }
4453 4455 }
4454 4456 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4455 4457 }
4456 4458 }
4457 4459
4458 4460 void Thread::SpinRelease (volatile int * adr) {
4459 4461 assert (*adr != 0, "invariant") ;
4460 4462 OrderAccess::fence() ; // guarantee at least release consistency.
4461 4463 // Roach-motel semantics.
4462 4464 // It's safe if subsequent LDs and STs float "up" into the critical section,
4463 4465 // but prior LDs and STs within the critical section can't be allowed
4464 4466 // to reorder or float past the ST that releases the lock.
4465 4467 *adr = 0 ;
4466 4468 }
4467 4469
4468 4470 // muxAcquire and muxRelease:
4469 4471 //
4470 4472 // * muxAcquire and muxRelease support a single-word lock-word construct.
4471 4473 // The LSB of the word is set IFF the lock is held.
4472 4474 // The remainder of the word points to the head of a singly-linked list
4473 4475 // of threads blocked on the lock.
4474 4476 //
4475 4477 // * The current implementation of muxAcquire-muxRelease uses its own
4476 4478 // dedicated Thread._MuxEvent instance. If we're interested in
4477 4479 // minimizing the peak number of extant ParkEvent instances then
4478 4480 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4479 4481 // as certain invariants were satisfied. Specifically, care would need
4480 4482 // to be taken with regards to consuming unpark() "permits".
4481 4483 // A safe rule of thumb is that a thread would never call muxAcquire()
4482 4484 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4483 4485 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4484 4486 // consume an unpark() permit intended for monitorenter, for instance.
4485 4487 // One way around this would be to widen the restricted-range semaphore
4486 4488 // implemented in park(). Another alternative would be to provide
4487 4489 // multiple instances of the PlatformEvent() for each thread. One
4488 4490 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4489 4491 //
4490 4492 // * Usage:
4491 4493 // -- Only as leaf locks
4492 4494 // -- for short-term locking only as muxAcquire does not perform
4493 4495 // thread state transitions.
4494 4496 //
4495 4497 // Alternatives:
4496 4498 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4497 4499 // but with parking or spin-then-park instead of pure spinning.
4498 4500 // * Use Taura-Oyama-Yonenzawa locks.
4499 4501 // * It's possible to construct a 1-0 lock if we encode the lockword as
4500 4502 // (List,LockByte). Acquire will CAS the full lockword while Release
4501 4503 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4502 4504 // acquiring threads use timers (ParkTimed) to detect and recover from
4503 4505 // the stranding window. Thread/Node structures must be aligned on 256-byte
4504 4506 // boundaries by using placement-new.
4505 4507 // * Augment MCS with advisory back-link fields maintained with CAS().
4506 4508 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4507 4509 // The validity of the backlinks must be ratified before we trust the value.
4508 4510 // If the backlinks are invalid the exiting thread must back-track through the
4509 4511 // the forward links, which are always trustworthy.
4510 4512 // * Add a successor indication. The LockWord is currently encoded as
4511 4513 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4512 4514 // to provide the usual futile-wakeup optimization.
4513 4515 // See RTStt for details.
4514 4516 // * Consider schedctl.sc_nopreempt to cover the critical section.
4515 4517 //
4516 4518
4517 4519
4518 4520 typedef volatile intptr_t MutexT ; // Mux Lock-word
4519 4521 enum MuxBits { LOCKBIT = 1 } ;
4520 4522
4521 4523 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4522 4524 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4523 4525 if (w == 0) return ;
4524 4526 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4525 4527 return ;
4526 4528 }
4527 4529
4528 4530 TEVENT (muxAcquire - Contention) ;
4529 4531 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4530 4532 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4531 4533 for (;;) {
4532 4534 int its = (os::is_MP() ? 100 : 0) + 1 ;
4533 4535
4534 4536 // Optional spin phase: spin-then-park strategy
4535 4537 while (--its >= 0) {
4536 4538 w = *Lock ;
4537 4539 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4538 4540 return ;
4539 4541 }
4540 4542 }
4541 4543
4542 4544 Self->reset() ;
4543 4545 Self->OnList = intptr_t(Lock) ;
4544 4546 // The following fence() isn't _strictly necessary as the subsequent
4545 4547 // CAS() both serializes execution and ratifies the fetched *Lock value.
4546 4548 OrderAccess::fence();
4547 4549 for (;;) {
4548 4550 w = *Lock ;
4549 4551 if ((w & LOCKBIT) == 0) {
4550 4552 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4551 4553 Self->OnList = 0 ; // hygiene - allows stronger asserts
4552 4554 return ;
4553 4555 }
4554 4556 continue ; // Interference -- *Lock changed -- Just retry
4555 4557 }
4556 4558 assert (w & LOCKBIT, "invariant") ;
4557 4559 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4558 4560 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4559 4561 }
4560 4562
4561 4563 while (Self->OnList != 0) {
4562 4564 Self->park() ;
4563 4565 }
4564 4566 }
4565 4567 }
4566 4568
4567 4569 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4568 4570 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4569 4571 if (w == 0) return ;
4570 4572 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4571 4573 return ;
4572 4574 }
4573 4575
4574 4576 TEVENT (muxAcquire - Contention) ;
4575 4577 ParkEvent * ReleaseAfter = NULL ;
4576 4578 if (ev == NULL) {
4577 4579 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4578 4580 }
4579 4581 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4580 4582 for (;;) {
4581 4583 guarantee (ev->OnList == 0, "invariant") ;
4582 4584 int its = (os::is_MP() ? 100 : 0) + 1 ;
4583 4585
4584 4586 // Optional spin phase: spin-then-park strategy
4585 4587 while (--its >= 0) {
4586 4588 w = *Lock ;
4587 4589 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4588 4590 if (ReleaseAfter != NULL) {
4589 4591 ParkEvent::Release (ReleaseAfter) ;
4590 4592 }
4591 4593 return ;
4592 4594 }
4593 4595 }
4594 4596
4595 4597 ev->reset() ;
4596 4598 ev->OnList = intptr_t(Lock) ;
4597 4599 // The following fence() isn't _strictly necessary as the subsequent
4598 4600 // CAS() both serializes execution and ratifies the fetched *Lock value.
4599 4601 OrderAccess::fence();
4600 4602 for (;;) {
4601 4603 w = *Lock ;
4602 4604 if ((w & LOCKBIT) == 0) {
4603 4605 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4604 4606 ev->OnList = 0 ;
4605 4607 // We call ::Release while holding the outer lock, thus
4606 4608 // artificially lengthening the critical section.
4607 4609 // Consider deferring the ::Release() until the subsequent unlock(),
4608 4610 // after we've dropped the outer lock.
4609 4611 if (ReleaseAfter != NULL) {
4610 4612 ParkEvent::Release (ReleaseAfter) ;
4611 4613 }
4612 4614 return ;
4613 4615 }
4614 4616 continue ; // Interference -- *Lock changed -- Just retry
4615 4617 }
4616 4618 assert (w & LOCKBIT, "invariant") ;
4617 4619 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4618 4620 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4619 4621 }
4620 4622
4621 4623 while (ev->OnList != 0) {
4622 4624 ev->park() ;
4623 4625 }
4624 4626 }
4625 4627 }
4626 4628
4627 4629 // Release() must extract a successor from the list and then wake that thread.
4628 4630 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4629 4631 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4630 4632 // Release() would :
4631 4633 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4632 4634 // (B) Extract a successor from the private list "in-hand"
4633 4635 // (C) attempt to CAS() the residual back into *Lock over null.
4634 4636 // If there were any newly arrived threads and the CAS() would fail.
4635 4637 // In that case Release() would detach the RATs, re-merge the list in-hand
4636 4638 // with the RATs and repeat as needed. Alternately, Release() might
4637 4639 // detach and extract a successor, but then pass the residual list to the wakee.
4638 4640 // The wakee would be responsible for reattaching and remerging before it
4639 4641 // competed for the lock.
4640 4642 //
4641 4643 // Both "pop" and DMR are immune from ABA corruption -- there can be
4642 4644 // multiple concurrent pushers, but only one popper or detacher.
4643 4645 // This implementation pops from the head of the list. This is unfair,
4644 4646 // but tends to provide excellent throughput as hot threads remain hot.
4645 4647 // (We wake recently run threads first).
4646 4648
4647 4649 void Thread::muxRelease (volatile intptr_t * Lock) {
4648 4650 for (;;) {
4649 4651 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4650 4652 assert (w & LOCKBIT, "invariant") ;
4651 4653 if (w == LOCKBIT) return ;
4652 4654 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4653 4655 assert (List != NULL, "invariant") ;
4654 4656 assert (List->OnList == intptr_t(Lock), "invariant") ;
4655 4657 ParkEvent * nxt = List->ListNext ;
4656 4658
4657 4659 // The following CAS() releases the lock and pops the head element.
4658 4660 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4659 4661 continue ;
4660 4662 }
4661 4663 List->OnList = 0 ;
4662 4664 OrderAccess::fence() ;
4663 4665 List->unpark () ;
4664 4666 return ;
4665 4667 }
4666 4668 }
4667 4669
4668 4670
4669 4671 void Threads::verify() {
4670 4672 ALL_JAVA_THREADS(p) {
4671 4673 p->verify();
4672 4674 }
4673 4675 VMThread* thread = VMThread::vm_thread();
4674 4676 if (thread != NULL) thread->verify();
4675 4677 }
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