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rev 2691 : [mq]: g1-reference-processing
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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, 2011, 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/oopFactory.hpp"
37 37 #include "memory/universe.inline.hpp"
38 38 #include "oops/instanceKlass.hpp"
39 39 #include "oops/objArrayOop.hpp"
40 40 #include "oops/oop.inline.hpp"
41 41 #include "oops/symbol.hpp"
42 42 #include "prims/jvm_misc.hpp"
43 43 #include "prims/jvmtiExport.hpp"
44 44 #include "prims/jvmtiThreadState.hpp"
45 45 #include "prims/privilegedStack.hpp"
46 46 #include "runtime/aprofiler.hpp"
47 47 #include "runtime/arguments.hpp"
48 48 #include "runtime/biasedLocking.hpp"
49 49 #include "runtime/deoptimization.hpp"
50 50 #include "runtime/fprofiler.hpp"
51 51 #include "runtime/frame.inline.hpp"
52 52 #include "runtime/init.hpp"
53 53 #include "runtime/interfaceSupport.hpp"
54 54 #include "runtime/java.hpp"
55 55 #include "runtime/javaCalls.hpp"
56 56 #include "runtime/jniPeriodicChecker.hpp"
57 57 #include "runtime/memprofiler.hpp"
58 58 #include "runtime/mutexLocker.hpp"
59 59 #include "runtime/objectMonitor.hpp"
60 60 #include "runtime/osThread.hpp"
61 61 #include "runtime/safepoint.hpp"
62 62 #include "runtime/sharedRuntime.hpp"
63 63 #include "runtime/statSampler.hpp"
64 64 #include "runtime/stubRoutines.hpp"
65 65 #include "runtime/task.hpp"
66 66 #include "runtime/threadCritical.hpp"
67 67 #include "runtime/threadLocalStorage.hpp"
68 68 #include "runtime/vframe.hpp"
69 69 #include "runtime/vframeArray.hpp"
70 70 #include "runtime/vframe_hp.hpp"
71 71 #include "runtime/vmThread.hpp"
72 72 #include "runtime/vm_operations.hpp"
73 73 #include "services/attachListener.hpp"
74 74 #include "services/management.hpp"
75 75 #include "services/threadService.hpp"
76 76 #include "utilities/defaultStream.hpp"
77 77 #include "utilities/dtrace.hpp"
78 78 #include "utilities/events.hpp"
79 79 #include "utilities/preserveException.hpp"
80 80 #ifdef TARGET_OS_FAMILY_linux
81 81 # include "os_linux.inline.hpp"
82 82 # include "thread_linux.inline.hpp"
83 83 #endif
84 84 #ifdef TARGET_OS_FAMILY_solaris
85 85 # include "os_solaris.inline.hpp"
86 86 # include "thread_solaris.inline.hpp"
87 87 #endif
88 88 #ifdef TARGET_OS_FAMILY_windows
89 89 # include "os_windows.inline.hpp"
90 90 # include "thread_windows.inline.hpp"
91 91 #endif
92 92 #ifndef SERIALGC
93 93 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
94 94 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
95 95 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
96 96 #endif
97 97 #ifdef COMPILER1
98 98 #include "c1/c1_Compiler.hpp"
99 99 #endif
100 100 #ifdef COMPILER2
101 101 #include "opto/c2compiler.hpp"
102 102 #include "opto/idealGraphPrinter.hpp"
103 103 #endif
104 104
105 105 #ifdef DTRACE_ENABLED
106 106
107 107 // Only bother with this argument setup if dtrace is available
108 108
109 109 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
110 110 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
111 111 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
112 112 intptr_t, intptr_t, bool);
113 113 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
114 114 intptr_t, intptr_t, bool);
115 115
116 116 #define DTRACE_THREAD_PROBE(probe, javathread) \
117 117 { \
118 118 ResourceMark rm(this); \
119 119 int len = 0; \
120 120 const char* name = (javathread)->get_thread_name(); \
121 121 len = strlen(name); \
122 122 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
123 123 name, len, \
124 124 java_lang_Thread::thread_id((javathread)->threadObj()), \
125 125 (javathread)->osthread()->thread_id(), \
126 126 java_lang_Thread::is_daemon((javathread)->threadObj())); \
127 127 }
128 128
129 129 #else // ndef DTRACE_ENABLED
130 130
131 131 #define DTRACE_THREAD_PROBE(probe, javathread)
132 132
133 133 #endif // ndef DTRACE_ENABLED
134 134
135 135 // Class hierarchy
136 136 // - Thread
137 137 // - VMThread
138 138 // - WatcherThread
139 139 // - ConcurrentMarkSweepThread
140 140 // - JavaThread
141 141 // - CompilerThread
142 142
143 143 // ======= Thread ========
144 144
145 145 // Support for forcing alignment of thread objects for biased locking
146 146 void* Thread::operator new(size_t size) {
147 147 if (UseBiasedLocking) {
148 148 const int alignment = markOopDesc::biased_lock_alignment;
149 149 size_t aligned_size = size + (alignment - sizeof(intptr_t));
150 150 void* real_malloc_addr = CHeapObj::operator new(aligned_size);
151 151 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
152 152 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
153 153 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
154 154 "JavaThread alignment code overflowed allocated storage");
155 155 if (TraceBiasedLocking) {
156 156 if (aligned_addr != real_malloc_addr)
157 157 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
158 158 real_malloc_addr, aligned_addr);
159 159 }
160 160 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
161 161 return aligned_addr;
162 162 } else {
163 163 return CHeapObj::operator new(size);
164 164 }
165 165 }
166 166
167 167 void Thread::operator delete(void* p) {
168 168 if (UseBiasedLocking) {
169 169 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
170 170 CHeapObj::operator delete(real_malloc_addr);
171 171 } else {
172 172 CHeapObj::operator delete(p);
173 173 }
174 174 }
175 175
176 176
177 177 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
178 178 // JavaThread
179 179
180 180
181 181 Thread::Thread() {
182 182 // stack and get_thread
183 183 set_stack_base(NULL);
184 184 set_stack_size(0);
185 185 set_self_raw_id(0);
186 186 set_lgrp_id(-1);
187 187
188 188 // allocated data structures
189 189 set_osthread(NULL);
190 190 set_resource_area(new ResourceArea());
191 191 set_handle_area(new HandleArea(NULL));
192 192 set_active_handles(NULL);
193 193 set_free_handle_block(NULL);
194 194 set_last_handle_mark(NULL);
195 195
196 196 // This initial value ==> never claimed.
197 197 _oops_do_parity = 0;
198 198
199 199 // the handle mark links itself to last_handle_mark
200 200 new HandleMark(this);
201 201
202 202 // plain initialization
203 203 debug_only(_owned_locks = NULL;)
204 204 debug_only(_allow_allocation_count = 0;)
205 205 NOT_PRODUCT(_allow_safepoint_count = 0;)
206 206 NOT_PRODUCT(_skip_gcalot = false;)
207 207 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
208 208 _jvmti_env_iteration_count = 0;
209 209 set_allocated_bytes(0);
210 210 _vm_operation_started_count = 0;
211 211 _vm_operation_completed_count = 0;
212 212 _current_pending_monitor = NULL;
213 213 _current_pending_monitor_is_from_java = true;
214 214 _current_waiting_monitor = NULL;
215 215 _num_nested_signal = 0;
216 216 omFreeList = NULL ;
217 217 omFreeCount = 0 ;
218 218 omFreeProvision = 32 ;
219 219 omInUseList = NULL ;
220 220 omInUseCount = 0 ;
221 221
222 222 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
223 223 _suspend_flags = 0;
224 224
225 225 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
226 226 _hashStateX = os::random() ;
227 227 _hashStateY = 842502087 ;
228 228 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
229 229 _hashStateW = 273326509 ;
230 230
231 231 _OnTrap = 0 ;
232 232 _schedctl = NULL ;
233 233 _Stalled = 0 ;
234 234 _TypeTag = 0x2BAD ;
235 235
236 236 // Many of the following fields are effectively final - immutable
237 237 // Note that nascent threads can't use the Native Monitor-Mutex
238 238 // construct until the _MutexEvent is initialized ...
239 239 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
240 240 // we might instead use a stack of ParkEvents that we could provision on-demand.
241 241 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
242 242 // and ::Release()
243 243 _ParkEvent = ParkEvent::Allocate (this) ;
244 244 _SleepEvent = ParkEvent::Allocate (this) ;
245 245 _MutexEvent = ParkEvent::Allocate (this) ;
246 246 _MuxEvent = ParkEvent::Allocate (this) ;
247 247
248 248 #ifdef CHECK_UNHANDLED_OOPS
249 249 if (CheckUnhandledOops) {
250 250 _unhandled_oops = new UnhandledOops(this);
251 251 }
252 252 #endif // CHECK_UNHANDLED_OOPS
253 253 #ifdef ASSERT
254 254 if (UseBiasedLocking) {
255 255 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
256 256 assert(this == _real_malloc_address ||
257 257 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
258 258 "bug in forced alignment of thread objects");
259 259 }
260 260 #endif /* ASSERT */
261 261 }
262 262
263 263 void Thread::initialize_thread_local_storage() {
264 264 // Note: Make sure this method only calls
265 265 // non-blocking operations. Otherwise, it might not work
266 266 // with the thread-startup/safepoint interaction.
267 267
268 268 // During Java thread startup, safepoint code should allow this
269 269 // method to complete because it may need to allocate memory to
270 270 // store information for the new thread.
271 271
272 272 // initialize structure dependent on thread local storage
273 273 ThreadLocalStorage::set_thread(this);
274 274
275 275 // set up any platform-specific state.
276 276 os::initialize_thread();
277 277
278 278 }
279 279
280 280 void Thread::record_stack_base_and_size() {
281 281 set_stack_base(os::current_stack_base());
282 282 set_stack_size(os::current_stack_size());
283 283 }
284 284
285 285
286 286 Thread::~Thread() {
287 287 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
288 288 ObjectSynchronizer::omFlush (this) ;
289 289
290 290 // deallocate data structures
291 291 delete resource_area();
292 292 // since the handle marks are using the handle area, we have to deallocated the root
293 293 // handle mark before deallocating the thread's handle area,
294 294 assert(last_handle_mark() != NULL, "check we have an element");
295 295 delete last_handle_mark();
296 296 assert(last_handle_mark() == NULL, "check we have reached the end");
297 297
298 298 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
299 299 // We NULL out the fields for good hygiene.
300 300 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
301 301 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
302 302 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
303 303 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
304 304
305 305 delete handle_area();
306 306
307 307 // osthread() can be NULL, if creation of thread failed.
308 308 if (osthread() != NULL) os::free_thread(osthread());
309 309
310 310 delete _SR_lock;
311 311
312 312 // clear thread local storage if the Thread is deleting itself
313 313 if (this == Thread::current()) {
314 314 ThreadLocalStorage::set_thread(NULL);
315 315 } else {
316 316 // In the case where we're not the current thread, invalidate all the
317 317 // caches in case some code tries to get the current thread or the
318 318 // thread that was destroyed, and gets stale information.
319 319 ThreadLocalStorage::invalidate_all();
320 320 }
321 321 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
322 322 }
323 323
324 324 // NOTE: dummy function for assertion purpose.
325 325 void Thread::run() {
326 326 ShouldNotReachHere();
327 327 }
328 328
329 329 #ifdef ASSERT
330 330 // Private method to check for dangling thread pointer
331 331 void check_for_dangling_thread_pointer(Thread *thread) {
332 332 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
333 333 "possibility of dangling Thread pointer");
334 334 }
335 335 #endif
336 336
337 337
338 338 #ifndef PRODUCT
339 339 // Tracing method for basic thread operations
340 340 void Thread::trace(const char* msg, const Thread* const thread) {
341 341 if (!TraceThreadEvents) return;
342 342 ResourceMark rm;
343 343 ThreadCritical tc;
344 344 const char *name = "non-Java thread";
345 345 int prio = -1;
346 346 if (thread->is_Java_thread()
347 347 && !thread->is_Compiler_thread()) {
348 348 // The Threads_lock must be held to get information about
349 349 // this thread but may not be in some situations when
350 350 // tracing thread events.
351 351 bool release_Threads_lock = false;
352 352 if (!Threads_lock->owned_by_self()) {
353 353 Threads_lock->lock();
354 354 release_Threads_lock = true;
355 355 }
356 356 JavaThread* jt = (JavaThread *)thread;
357 357 name = (char *)jt->get_thread_name();
358 358 oop thread_oop = jt->threadObj();
359 359 if (thread_oop != NULL) {
360 360 prio = java_lang_Thread::priority(thread_oop);
361 361 }
362 362 if (release_Threads_lock) {
363 363 Threads_lock->unlock();
364 364 }
365 365 }
366 366 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
367 367 }
368 368 #endif
369 369
370 370
371 371 ThreadPriority Thread::get_priority(const Thread* const thread) {
372 372 trace("get priority", thread);
373 373 ThreadPriority priority;
374 374 // Can return an error!
375 375 (void)os::get_priority(thread, priority);
376 376 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
377 377 return priority;
378 378 }
379 379
380 380 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
381 381 trace("set priority", thread);
382 382 debug_only(check_for_dangling_thread_pointer(thread);)
383 383 // Can return an error!
384 384 (void)os::set_priority(thread, priority);
385 385 }
386 386
387 387
388 388 void Thread::start(Thread* thread) {
389 389 trace("start", thread);
390 390 // Start is different from resume in that its safety is guaranteed by context or
391 391 // being called from a Java method synchronized on the Thread object.
392 392 if (!DisableStartThread) {
393 393 if (thread->is_Java_thread()) {
394 394 // Initialize the thread state to RUNNABLE before starting this thread.
395 395 // Can not set it after the thread started because we do not know the
396 396 // exact thread state at that time. It could be in MONITOR_WAIT or
397 397 // in SLEEPING or some other state.
398 398 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
399 399 java_lang_Thread::RUNNABLE);
400 400 }
401 401 os::start_thread(thread);
402 402 }
403 403 }
404 404
405 405 // Enqueue a VM_Operation to do the job for us - sometime later
406 406 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
407 407 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
408 408 VMThread::execute(vm_stop);
409 409 }
410 410
411 411
412 412 //
413 413 // Check if an external suspend request has completed (or has been
414 414 // cancelled). Returns true if the thread is externally suspended and
415 415 // false otherwise.
416 416 //
417 417 // The bits parameter returns information about the code path through
418 418 // the routine. Useful for debugging:
419 419 //
420 420 // set in is_ext_suspend_completed():
421 421 // 0x00000001 - routine was entered
422 422 // 0x00000010 - routine return false at end
423 423 // 0x00000100 - thread exited (return false)
424 424 // 0x00000200 - suspend request cancelled (return false)
425 425 // 0x00000400 - thread suspended (return true)
426 426 // 0x00001000 - thread is in a suspend equivalent state (return true)
427 427 // 0x00002000 - thread is native and walkable (return true)
428 428 // 0x00004000 - thread is native_trans and walkable (needed retry)
429 429 //
430 430 // set in wait_for_ext_suspend_completion():
431 431 // 0x00010000 - routine was entered
432 432 // 0x00020000 - suspend request cancelled before loop (return false)
433 433 // 0x00040000 - thread suspended before loop (return true)
434 434 // 0x00080000 - suspend request cancelled in loop (return false)
435 435 // 0x00100000 - thread suspended in loop (return true)
436 436 // 0x00200000 - suspend not completed during retry loop (return false)
437 437 //
438 438
439 439 // Helper class for tracing suspend wait debug bits.
440 440 //
441 441 // 0x00000100 indicates that the target thread exited before it could
442 442 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
443 443 // 0x00080000 each indicate a cancelled suspend request so they don't
444 444 // count as wait failures either.
445 445 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
446 446
447 447 class TraceSuspendDebugBits : public StackObj {
448 448 private:
449 449 JavaThread * jt;
450 450 bool is_wait;
451 451 bool called_by_wait; // meaningful when !is_wait
452 452 uint32_t * bits;
453 453
454 454 public:
455 455 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
456 456 uint32_t *_bits) {
457 457 jt = _jt;
458 458 is_wait = _is_wait;
459 459 called_by_wait = _called_by_wait;
460 460 bits = _bits;
461 461 }
462 462
463 463 ~TraceSuspendDebugBits() {
464 464 if (!is_wait) {
465 465 #if 1
466 466 // By default, don't trace bits for is_ext_suspend_completed() calls.
467 467 // That trace is very chatty.
468 468 return;
469 469 #else
470 470 if (!called_by_wait) {
471 471 // If tracing for is_ext_suspend_completed() is enabled, then only
472 472 // trace calls to it from wait_for_ext_suspend_completion()
473 473 return;
474 474 }
475 475 #endif
476 476 }
477 477
478 478 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
479 479 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
480 480 MutexLocker ml(Threads_lock); // needed for get_thread_name()
481 481 ResourceMark rm;
482 482
483 483 tty->print_cr(
484 484 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
485 485 jt->get_thread_name(), *bits);
486 486
487 487 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
488 488 }
489 489 }
490 490 }
491 491 };
492 492 #undef DEBUG_FALSE_BITS
493 493
494 494
495 495 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
496 496 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
497 497
498 498 bool did_trans_retry = false; // only do thread_in_native_trans retry once
499 499 bool do_trans_retry; // flag to force the retry
500 500
501 501 *bits |= 0x00000001;
502 502
503 503 do {
504 504 do_trans_retry = false;
505 505
506 506 if (is_exiting()) {
507 507 // Thread is in the process of exiting. This is always checked
508 508 // first to reduce the risk of dereferencing a freed JavaThread.
509 509 *bits |= 0x00000100;
510 510 return false;
511 511 }
512 512
513 513 if (!is_external_suspend()) {
514 514 // Suspend request is cancelled. This is always checked before
515 515 // is_ext_suspended() to reduce the risk of a rogue resume
516 516 // confusing the thread that made the suspend request.
517 517 *bits |= 0x00000200;
518 518 return false;
519 519 }
520 520
521 521 if (is_ext_suspended()) {
522 522 // thread is suspended
523 523 *bits |= 0x00000400;
524 524 return true;
525 525 }
526 526
527 527 // Now that we no longer do hard suspends of threads running
528 528 // native code, the target thread can be changing thread state
529 529 // while we are in this routine:
530 530 //
531 531 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
532 532 //
533 533 // We save a copy of the thread state as observed at this moment
534 534 // and make our decision about suspend completeness based on the
535 535 // copy. This closes the race where the thread state is seen as
536 536 // _thread_in_native_trans in the if-thread_blocked check, but is
537 537 // seen as _thread_blocked in if-thread_in_native_trans check.
538 538 JavaThreadState save_state = thread_state();
539 539
540 540 if (save_state == _thread_blocked && is_suspend_equivalent()) {
541 541 // If the thread's state is _thread_blocked and this blocking
542 542 // condition is known to be equivalent to a suspend, then we can
543 543 // consider the thread to be externally suspended. This means that
544 544 // the code that sets _thread_blocked has been modified to do
545 545 // self-suspension if the blocking condition releases. We also
546 546 // used to check for CONDVAR_WAIT here, but that is now covered by
547 547 // the _thread_blocked with self-suspension check.
548 548 //
549 549 // Return true since we wouldn't be here unless there was still an
550 550 // external suspend request.
551 551 *bits |= 0x00001000;
552 552 return true;
553 553 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
554 554 // Threads running native code will self-suspend on native==>VM/Java
555 555 // transitions. If its stack is walkable (should always be the case
556 556 // unless this function is called before the actual java_suspend()
557 557 // call), then the wait is done.
558 558 *bits |= 0x00002000;
559 559 return true;
560 560 } else if (!called_by_wait && !did_trans_retry &&
561 561 save_state == _thread_in_native_trans &&
562 562 frame_anchor()->walkable()) {
563 563 // The thread is transitioning from thread_in_native to another
564 564 // thread state. check_safepoint_and_suspend_for_native_trans()
565 565 // will force the thread to self-suspend. If it hasn't gotten
566 566 // there yet we may have caught the thread in-between the native
567 567 // code check above and the self-suspend. Lucky us. If we were
568 568 // called by wait_for_ext_suspend_completion(), then it
569 569 // will be doing the retries so we don't have to.
570 570 //
571 571 // Since we use the saved thread state in the if-statement above,
572 572 // there is a chance that the thread has already transitioned to
573 573 // _thread_blocked by the time we get here. In that case, we will
574 574 // make a single unnecessary pass through the logic below. This
575 575 // doesn't hurt anything since we still do the trans retry.
576 576
577 577 *bits |= 0x00004000;
578 578
579 579 // Once the thread leaves thread_in_native_trans for another
580 580 // thread state, we break out of this retry loop. We shouldn't
581 581 // need this flag to prevent us from getting back here, but
582 582 // sometimes paranoia is good.
583 583 did_trans_retry = true;
584 584
585 585 // We wait for the thread to transition to a more usable state.
586 586 for (int i = 1; i <= SuspendRetryCount; i++) {
587 587 // We used to do an "os::yield_all(i)" call here with the intention
588 588 // that yielding would increase on each retry. However, the parameter
589 589 // is ignored on Linux which means the yield didn't scale up. Waiting
590 590 // on the SR_lock below provides a much more predictable scale up for
591 591 // the delay. It also provides a simple/direct point to check for any
592 592 // safepoint requests from the VMThread
593 593
594 594 // temporarily drops SR_lock while doing wait with safepoint check
595 595 // (if we're a JavaThread - the WatcherThread can also call this)
596 596 // and increase delay with each retry
597 597 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
598 598
599 599 // check the actual thread state instead of what we saved above
600 600 if (thread_state() != _thread_in_native_trans) {
601 601 // the thread has transitioned to another thread state so
602 602 // try all the checks (except this one) one more time.
603 603 do_trans_retry = true;
604 604 break;
605 605 }
606 606 } // end retry loop
607 607
608 608
609 609 }
610 610 } while (do_trans_retry);
611 611
612 612 *bits |= 0x00000010;
613 613 return false;
614 614 }
615 615
616 616 //
617 617 // Wait for an external suspend request to complete (or be cancelled).
618 618 // Returns true if the thread is externally suspended and false otherwise.
619 619 //
620 620 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
621 621 uint32_t *bits) {
622 622 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
623 623 false /* !called_by_wait */, bits);
624 624
625 625 // local flag copies to minimize SR_lock hold time
626 626 bool is_suspended;
627 627 bool pending;
628 628 uint32_t reset_bits;
629 629
630 630 // set a marker so is_ext_suspend_completed() knows we are the caller
631 631 *bits |= 0x00010000;
632 632
633 633 // We use reset_bits to reinitialize the bits value at the top of
634 634 // each retry loop. This allows the caller to make use of any
635 635 // unused bits for their own marking purposes.
636 636 reset_bits = *bits;
637 637
638 638 {
639 639 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
640 640 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
641 641 delay, bits);
642 642 pending = is_external_suspend();
643 643 }
644 644 // must release SR_lock to allow suspension to complete
645 645
646 646 if (!pending) {
647 647 // A cancelled suspend request is the only false return from
648 648 // is_ext_suspend_completed() that keeps us from entering the
649 649 // retry loop.
650 650 *bits |= 0x00020000;
651 651 return false;
652 652 }
653 653
654 654 if (is_suspended) {
655 655 *bits |= 0x00040000;
656 656 return true;
657 657 }
658 658
659 659 for (int i = 1; i <= retries; i++) {
660 660 *bits = reset_bits; // reinit to only track last retry
661 661
662 662 // We used to do an "os::yield_all(i)" call here with the intention
663 663 // that yielding would increase on each retry. However, the parameter
664 664 // is ignored on Linux which means the yield didn't scale up. Waiting
665 665 // on the SR_lock below provides a much more predictable scale up for
666 666 // the delay. It also provides a simple/direct point to check for any
667 667 // safepoint requests from the VMThread
668 668
669 669 {
670 670 MutexLocker ml(SR_lock());
671 671 // wait with safepoint check (if we're a JavaThread - the WatcherThread
672 672 // can also call this) and increase delay with each retry
673 673 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
674 674
675 675 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
676 676 delay, bits);
677 677
678 678 // It is possible for the external suspend request to be cancelled
679 679 // (by a resume) before the actual suspend operation is completed.
680 680 // Refresh our local copy to see if we still need to wait.
681 681 pending = is_external_suspend();
682 682 }
683 683
684 684 if (!pending) {
685 685 // A cancelled suspend request is the only false return from
686 686 // is_ext_suspend_completed() that keeps us from staying in the
687 687 // retry loop.
688 688 *bits |= 0x00080000;
689 689 return false;
690 690 }
691 691
692 692 if (is_suspended) {
693 693 *bits |= 0x00100000;
694 694 return true;
695 695 }
696 696 } // end retry loop
697 697
698 698 // thread did not suspend after all our retries
699 699 *bits |= 0x00200000;
700 700 return false;
701 701 }
702 702
703 703 #ifndef PRODUCT
704 704 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
705 705
706 706 // This should not need to be atomic as the only way for simultaneous
707 707 // updates is via interrupts. Even then this should be rare or non-existant
708 708 // and we don't care that much anyway.
709 709
710 710 int index = _jmp_ring_index;
711 711 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
712 712 _jmp_ring[index]._target = (intptr_t) target;
713 713 _jmp_ring[index]._instruction = (intptr_t) instr;
714 714 _jmp_ring[index]._file = file;
715 715 _jmp_ring[index]._line = line;
716 716 }
717 717 #endif /* PRODUCT */
718 718
719 719 // Called by flat profiler
720 720 // Callers have already called wait_for_ext_suspend_completion
721 721 // The assertion for that is currently too complex to put here:
722 722 bool JavaThread::profile_last_Java_frame(frame* _fr) {
723 723 bool gotframe = false;
724 724 // self suspension saves needed state.
725 725 if (has_last_Java_frame() && _anchor.walkable()) {
726 726 *_fr = pd_last_frame();
727 727 gotframe = true;
728 728 }
729 729 return gotframe;
730 730 }
731 731
732 732 void Thread::interrupt(Thread* thread) {
733 733 trace("interrupt", thread);
734 734 debug_only(check_for_dangling_thread_pointer(thread);)
735 735 os::interrupt(thread);
736 736 }
737 737
738 738 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
739 739 trace("is_interrupted", thread);
740 740 debug_only(check_for_dangling_thread_pointer(thread);)
741 741 // Note: If clear_interrupted==false, this simply fetches and
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742 742 // returns the value of the field osthread()->interrupted().
743 743 return os::is_interrupted(thread, clear_interrupted);
744 744 }
745 745
746 746
747 747 // GC Support
748 748 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
749 749 jint thread_parity = _oops_do_parity;
750 750 if (thread_parity != strong_roots_parity) {
751 751 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
752 - if (res == thread_parity) return true;
753 - else {
752 + if (res == thread_parity) {
753 + return true;
754 + } else {
754 755 guarantee(res == strong_roots_parity, "Or else what?");
755 756 assert(SharedHeap::heap()->n_par_threads() > 0,
756 757 "Should only fail when parallel.");
757 758 return false;
758 759 }
759 760 }
760 761 assert(SharedHeap::heap()->n_par_threads() > 0,
761 762 "Should only fail when parallel.");
762 763 return false;
763 764 }
764 765
765 766 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
766 767 active_handles()->oops_do(f);
767 768 // Do oop for ThreadShadow
768 769 f->do_oop((oop*)&_pending_exception);
769 770 handle_area()->oops_do(f);
770 771 }
771 772
772 773 void Thread::nmethods_do(CodeBlobClosure* cf) {
773 774 // no nmethods in a generic thread...
774 775 }
775 776
776 777 void Thread::print_on(outputStream* st) const {
777 778 // get_priority assumes osthread initialized
778 779 if (osthread() != NULL) {
779 780 st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this);
780 781 osthread()->print_on(st);
781 782 }
782 783 debug_only(if (WizardMode) print_owned_locks_on(st);)
783 784 }
784 785
785 786 // Thread::print_on_error() is called by fatal error handler. Don't use
786 787 // any lock or allocate memory.
787 788 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
788 789 if (is_VM_thread()) st->print("VMThread");
789 790 else if (is_Compiler_thread()) st->print("CompilerThread");
790 791 else if (is_Java_thread()) st->print("JavaThread");
791 792 else if (is_GC_task_thread()) st->print("GCTaskThread");
792 793 else if (is_Watcher_thread()) st->print("WatcherThread");
793 794 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
794 795 else st->print("Thread");
795 796
796 797 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
797 798 _stack_base - _stack_size, _stack_base);
798 799
799 800 if (osthread()) {
800 801 st->print(" [id=%d]", osthread()->thread_id());
801 802 }
802 803 }
803 804
804 805 #ifdef ASSERT
805 806 void Thread::print_owned_locks_on(outputStream* st) const {
806 807 Monitor *cur = _owned_locks;
807 808 if (cur == NULL) {
808 809 st->print(" (no locks) ");
809 810 } else {
810 811 st->print_cr(" Locks owned:");
811 812 while(cur) {
812 813 cur->print_on(st);
813 814 cur = cur->next();
814 815 }
815 816 }
816 817 }
817 818
818 819 static int ref_use_count = 0;
819 820
820 821 bool Thread::owns_locks_but_compiled_lock() const {
821 822 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
822 823 if (cur != Compile_lock) return true;
823 824 }
824 825 return false;
825 826 }
826 827
827 828
828 829 #endif
829 830
830 831 #ifndef PRODUCT
831 832
832 833 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
833 834 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
834 835 // no threads which allow_vm_block's are held
835 836 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
836 837 // Check if current thread is allowed to block at a safepoint
837 838 if (!(_allow_safepoint_count == 0))
838 839 fatal("Possible safepoint reached by thread that does not allow it");
839 840 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
840 841 fatal("LEAF method calling lock?");
841 842 }
842 843
843 844 #ifdef ASSERT
844 845 if (potential_vm_operation && is_Java_thread()
845 846 && !Universe::is_bootstrapping()) {
846 847 // Make sure we do not hold any locks that the VM thread also uses.
847 848 // This could potentially lead to deadlocks
848 849 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
849 850 // Threads_lock is special, since the safepoint synchronization will not start before this is
850 851 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
851 852 // since it is used to transfer control between JavaThreads and the VMThread
852 853 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
853 854 if ( (cur->allow_vm_block() &&
854 855 cur != Threads_lock &&
855 856 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
856 857 cur != VMOperationRequest_lock &&
857 858 cur != VMOperationQueue_lock) ||
858 859 cur->rank() == Mutex::special) {
859 860 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
860 861 }
861 862 }
862 863 }
863 864
864 865 if (GCALotAtAllSafepoints) {
865 866 // We could enter a safepoint here and thus have a gc
866 867 InterfaceSupport::check_gc_alot();
867 868 }
868 869 #endif
869 870 }
870 871 #endif
871 872
872 873 bool Thread::is_in_stack(address adr) const {
873 874 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
874 875 address end = os::current_stack_pointer();
875 876 if (stack_base() >= adr && adr >= end) return true;
876 877
877 878 return false;
878 879 }
879 880
880 881
881 882 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
882 883 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
883 884 // used for compilation in the future. If that change is made, the need for these methods
884 885 // should be revisited, and they should be removed if possible.
885 886
886 887 bool Thread::is_lock_owned(address adr) const {
887 888 return on_local_stack(adr);
888 889 }
889 890
890 891 bool Thread::set_as_starting_thread() {
891 892 // NOTE: this must be called inside the main thread.
892 893 return os::create_main_thread((JavaThread*)this);
893 894 }
894 895
895 896 static void initialize_class(Symbol* class_name, TRAPS) {
896 897 klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
897 898 instanceKlass::cast(klass)->initialize(CHECK);
898 899 }
899 900
900 901
901 902 // Creates the initial ThreadGroup
902 903 static Handle create_initial_thread_group(TRAPS) {
903 904 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
904 905 instanceKlassHandle klass (THREAD, k);
905 906
906 907 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
907 908 {
908 909 JavaValue result(T_VOID);
909 910 JavaCalls::call_special(&result,
910 911 system_instance,
911 912 klass,
912 913 vmSymbols::object_initializer_name(),
913 914 vmSymbols::void_method_signature(),
914 915 CHECK_NH);
915 916 }
916 917 Universe::set_system_thread_group(system_instance());
917 918
918 919 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
919 920 {
920 921 JavaValue result(T_VOID);
921 922 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
922 923 JavaCalls::call_special(&result,
923 924 main_instance,
924 925 klass,
925 926 vmSymbols::object_initializer_name(),
926 927 vmSymbols::threadgroup_string_void_signature(),
927 928 system_instance,
928 929 string,
929 930 CHECK_NH);
930 931 }
931 932 return main_instance;
932 933 }
933 934
934 935 // Creates the initial Thread
935 936 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
936 937 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
937 938 instanceKlassHandle klass (THREAD, k);
938 939 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
939 940
940 941 java_lang_Thread::set_thread(thread_oop(), thread);
941 942 java_lang_Thread::set_priority(thread_oop(), NormPriority);
942 943 thread->set_threadObj(thread_oop());
943 944
944 945 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
945 946
946 947 JavaValue result(T_VOID);
947 948 JavaCalls::call_special(&result, thread_oop,
948 949 klass,
949 950 vmSymbols::object_initializer_name(),
950 951 vmSymbols::threadgroup_string_void_signature(),
951 952 thread_group,
952 953 string,
953 954 CHECK_NULL);
954 955 return thread_oop();
955 956 }
956 957
957 958 static void call_initializeSystemClass(TRAPS) {
958 959 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
959 960 instanceKlassHandle klass (THREAD, k);
960 961
961 962 JavaValue result(T_VOID);
962 963 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
963 964 vmSymbols::void_method_signature(), CHECK);
964 965 }
965 966
966 967 // General purpose hook into Java code, run once when the VM is initialized.
967 968 // The Java library method itself may be changed independently from the VM.
968 969 static void call_postVMInitHook(TRAPS) {
969 970 klassOop k = SystemDictionary::sun_misc_PostVMInitHook_klass();
970 971 instanceKlassHandle klass (THREAD, k);
971 972 if (klass.not_null()) {
972 973 JavaValue result(T_VOID);
973 974 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
974 975 vmSymbols::void_method_signature(),
975 976 CHECK);
976 977 }
977 978 }
978 979
979 980 static void reset_vm_info_property(TRAPS) {
980 981 // the vm info string
981 982 ResourceMark rm(THREAD);
982 983 const char *vm_info = VM_Version::vm_info_string();
983 984
984 985 // java.lang.System class
985 986 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
986 987 instanceKlassHandle klass (THREAD, k);
987 988
988 989 // setProperty arguments
989 990 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
990 991 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
991 992
992 993 // return value
993 994 JavaValue r(T_OBJECT);
994 995
995 996 // public static String setProperty(String key, String value);
996 997 JavaCalls::call_static(&r,
997 998 klass,
998 999 vmSymbols::setProperty_name(),
999 1000 vmSymbols::string_string_string_signature(),
1000 1001 key_str,
1001 1002 value_str,
1002 1003 CHECK);
1003 1004 }
1004 1005
1005 1006
1006 1007 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1007 1008 assert(thread_group.not_null(), "thread group should be specified");
1008 1009 assert(threadObj() == NULL, "should only create Java thread object once");
1009 1010
1010 1011 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1011 1012 instanceKlassHandle klass (THREAD, k);
1012 1013 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1013 1014
1014 1015 java_lang_Thread::set_thread(thread_oop(), this);
1015 1016 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1016 1017 set_threadObj(thread_oop());
1017 1018
1018 1019 JavaValue result(T_VOID);
1019 1020 if (thread_name != NULL) {
1020 1021 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1021 1022 // Thread gets assigned specified name and null target
1022 1023 JavaCalls::call_special(&result,
1023 1024 thread_oop,
1024 1025 klass,
1025 1026 vmSymbols::object_initializer_name(),
1026 1027 vmSymbols::threadgroup_string_void_signature(),
1027 1028 thread_group, // Argument 1
1028 1029 name, // Argument 2
1029 1030 THREAD);
1030 1031 } else {
1031 1032 // Thread gets assigned name "Thread-nnn" and null target
1032 1033 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1033 1034 JavaCalls::call_special(&result,
1034 1035 thread_oop,
1035 1036 klass,
1036 1037 vmSymbols::object_initializer_name(),
1037 1038 vmSymbols::threadgroup_runnable_void_signature(),
1038 1039 thread_group, // Argument 1
1039 1040 Handle(), // Argument 2
1040 1041 THREAD);
1041 1042 }
1042 1043
1043 1044
1044 1045 if (daemon) {
1045 1046 java_lang_Thread::set_daemon(thread_oop());
1046 1047 }
1047 1048
1048 1049 if (HAS_PENDING_EXCEPTION) {
1049 1050 return;
1050 1051 }
1051 1052
1052 1053 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1053 1054 Handle threadObj(this, this->threadObj());
1054 1055
1055 1056 JavaCalls::call_special(&result,
1056 1057 thread_group,
1057 1058 group,
1058 1059 vmSymbols::add_method_name(),
1059 1060 vmSymbols::thread_void_signature(),
1060 1061 threadObj, // Arg 1
1061 1062 THREAD);
1062 1063
1063 1064
1064 1065 }
1065 1066
1066 1067 // NamedThread -- non-JavaThread subclasses with multiple
1067 1068 // uniquely named instances should derive from this.
1068 1069 NamedThread::NamedThread() : Thread() {
1069 1070 _name = NULL;
1070 1071 _processed_thread = NULL;
1071 1072 }
1072 1073
1073 1074 NamedThread::~NamedThread() {
1074 1075 if (_name != NULL) {
1075 1076 FREE_C_HEAP_ARRAY(char, _name);
1076 1077 _name = NULL;
1077 1078 }
1078 1079 }
1079 1080
1080 1081 void NamedThread::set_name(const char* format, ...) {
1081 1082 guarantee(_name == NULL, "Only get to set name once.");
1082 1083 _name = NEW_C_HEAP_ARRAY(char, max_name_len);
1083 1084 guarantee(_name != NULL, "alloc failure");
1084 1085 va_list ap;
1085 1086 va_start(ap, format);
1086 1087 jio_vsnprintf(_name, max_name_len, format, ap);
1087 1088 va_end(ap);
1088 1089 }
1089 1090
1090 1091 // ======= WatcherThread ========
1091 1092
1092 1093 // The watcher thread exists to simulate timer interrupts. It should
1093 1094 // be replaced by an abstraction over whatever native support for
1094 1095 // timer interrupts exists on the platform.
1095 1096
1096 1097 WatcherThread* WatcherThread::_watcher_thread = NULL;
1097 1098 volatile bool WatcherThread::_should_terminate = false;
1098 1099
1099 1100 WatcherThread::WatcherThread() : Thread() {
1100 1101 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1101 1102 if (os::create_thread(this, os::watcher_thread)) {
1102 1103 _watcher_thread = this;
1103 1104
1104 1105 // Set the watcher thread to the highest OS priority which should not be
1105 1106 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1106 1107 // is created. The only normal thread using this priority is the reference
1107 1108 // handler thread, which runs for very short intervals only.
1108 1109 // If the VMThread's priority is not lower than the WatcherThread profiling
1109 1110 // will be inaccurate.
1110 1111 os::set_priority(this, MaxPriority);
1111 1112 if (!DisableStartThread) {
1112 1113 os::start_thread(this);
1113 1114 }
1114 1115 }
1115 1116 }
1116 1117
1117 1118 void WatcherThread::run() {
1118 1119 assert(this == watcher_thread(), "just checking");
1119 1120
1120 1121 this->record_stack_base_and_size();
1121 1122 this->initialize_thread_local_storage();
1122 1123 this->set_active_handles(JNIHandleBlock::allocate_block());
1123 1124 while(!_should_terminate) {
1124 1125 assert(watcher_thread() == Thread::current(), "thread consistency check");
1125 1126 assert(watcher_thread() == this, "thread consistency check");
1126 1127
1127 1128 // Calculate how long it'll be until the next PeriodicTask work
1128 1129 // should be done, and sleep that amount of time.
1129 1130 size_t time_to_wait = PeriodicTask::time_to_wait();
1130 1131
1131 1132 // we expect this to timeout - we only ever get unparked when
1132 1133 // we should terminate
1133 1134 {
1134 1135 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1135 1136
1136 1137 jlong prev_time = os::javaTimeNanos();
1137 1138 for (;;) {
1138 1139 int res= _SleepEvent->park(time_to_wait);
1139 1140 if (res == OS_TIMEOUT || _should_terminate)
1140 1141 break;
1141 1142 // spurious wakeup of some kind
1142 1143 jlong now = os::javaTimeNanos();
1143 1144 time_to_wait -= (now - prev_time) / 1000000;
1144 1145 if (time_to_wait <= 0)
1145 1146 break;
1146 1147 prev_time = now;
1147 1148 }
1148 1149 }
1149 1150
1150 1151 if (is_error_reported()) {
1151 1152 // A fatal error has happened, the error handler(VMError::report_and_die)
1152 1153 // should abort JVM after creating an error log file. However in some
1153 1154 // rare cases, the error handler itself might deadlock. Here we try to
1154 1155 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1155 1156 //
1156 1157 // This code is in WatcherThread because WatcherThread wakes up
1157 1158 // periodically so the fatal error handler doesn't need to do anything;
1158 1159 // also because the WatcherThread is less likely to crash than other
1159 1160 // threads.
1160 1161
1161 1162 for (;;) {
1162 1163 if (!ShowMessageBoxOnError
1163 1164 && (OnError == NULL || OnError[0] == '\0')
1164 1165 && Arguments::abort_hook() == NULL) {
1165 1166 os::sleep(this, 2 * 60 * 1000, false);
1166 1167 fdStream err(defaultStream::output_fd());
1167 1168 err.print_raw_cr("# [ timer expired, abort... ]");
1168 1169 // skip atexit/vm_exit/vm_abort hooks
1169 1170 os::die();
1170 1171 }
1171 1172
1172 1173 // Wake up 5 seconds later, the fatal handler may reset OnError or
1173 1174 // ShowMessageBoxOnError when it is ready to abort.
1174 1175 os::sleep(this, 5 * 1000, false);
1175 1176 }
1176 1177 }
1177 1178
1178 1179 PeriodicTask::real_time_tick(time_to_wait);
1179 1180
1180 1181 // If we have no more tasks left due to dynamic disenrollment,
1181 1182 // shut down the thread since we don't currently support dynamic enrollment
1182 1183 if (PeriodicTask::num_tasks() == 0) {
1183 1184 _should_terminate = true;
1184 1185 }
1185 1186 }
1186 1187
1187 1188 // Signal that it is terminated
1188 1189 {
1189 1190 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1190 1191 _watcher_thread = NULL;
1191 1192 Terminator_lock->notify();
1192 1193 }
1193 1194
1194 1195 // Thread destructor usually does this..
1195 1196 ThreadLocalStorage::set_thread(NULL);
1196 1197 }
1197 1198
1198 1199 void WatcherThread::start() {
1199 1200 if (watcher_thread() == NULL) {
1200 1201 _should_terminate = false;
1201 1202 // Create the single instance of WatcherThread
1202 1203 new WatcherThread();
1203 1204 }
1204 1205 }
1205 1206
1206 1207 void WatcherThread::stop() {
1207 1208 // it is ok to take late safepoints here, if needed
1208 1209 MutexLocker mu(Terminator_lock);
1209 1210 _should_terminate = true;
1210 1211 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1211 1212
1212 1213 Thread* watcher = watcher_thread();
1213 1214 if (watcher != NULL)
1214 1215 watcher->_SleepEvent->unpark();
1215 1216
1216 1217 while(watcher_thread() != NULL) {
1217 1218 // This wait should make safepoint checks, wait without a timeout,
1218 1219 // and wait as a suspend-equivalent condition.
1219 1220 //
1220 1221 // Note: If the FlatProfiler is running, then this thread is waiting
1221 1222 // for the WatcherThread to terminate and the WatcherThread, via the
1222 1223 // FlatProfiler task, is waiting for the external suspend request on
1223 1224 // this thread to complete. wait_for_ext_suspend_completion() will
1224 1225 // eventually timeout, but that takes time. Making this wait a
1225 1226 // suspend-equivalent condition solves that timeout problem.
1226 1227 //
1227 1228 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1228 1229 Mutex::_as_suspend_equivalent_flag);
1229 1230 }
1230 1231 }
1231 1232
1232 1233 void WatcherThread::print_on(outputStream* st) const {
1233 1234 st->print("\"%s\" ", name());
1234 1235 Thread::print_on(st);
1235 1236 st->cr();
1236 1237 }
1237 1238
1238 1239 // ======= JavaThread ========
1239 1240
1240 1241 // A JavaThread is a normal Java thread
1241 1242
1242 1243 void JavaThread::initialize() {
1243 1244 // Initialize fields
1244 1245
1245 1246 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1246 1247 set_claimed_par_id(-1);
1247 1248
1248 1249 set_saved_exception_pc(NULL);
1249 1250 set_threadObj(NULL);
1250 1251 _anchor.clear();
1251 1252 set_entry_point(NULL);
1252 1253 set_jni_functions(jni_functions());
1253 1254 set_callee_target(NULL);
1254 1255 set_vm_result(NULL);
1255 1256 set_vm_result_2(NULL);
1256 1257 set_vframe_array_head(NULL);
1257 1258 set_vframe_array_last(NULL);
1258 1259 set_deferred_locals(NULL);
1259 1260 set_deopt_mark(NULL);
1260 1261 set_deopt_nmethod(NULL);
1261 1262 clear_must_deopt_id();
1262 1263 set_monitor_chunks(NULL);
1263 1264 set_next(NULL);
1264 1265 set_thread_state(_thread_new);
1265 1266 _terminated = _not_terminated;
1266 1267 _privileged_stack_top = NULL;
1267 1268 _array_for_gc = NULL;
1268 1269 _suspend_equivalent = false;
1269 1270 _in_deopt_handler = 0;
1270 1271 _doing_unsafe_access = false;
1271 1272 _stack_guard_state = stack_guard_unused;
1272 1273 _exception_oop = NULL;
1273 1274 _exception_pc = 0;
1274 1275 _exception_handler_pc = 0;
1275 1276 _is_method_handle_return = 0;
1276 1277 _jvmti_thread_state= NULL;
1277 1278 _should_post_on_exceptions_flag = JNI_FALSE;
1278 1279 _jvmti_get_loaded_classes_closure = NULL;
1279 1280 _interp_only_mode = 0;
1280 1281 _special_runtime_exit_condition = _no_async_condition;
1281 1282 _pending_async_exception = NULL;
1282 1283 _is_compiling = false;
1283 1284 _thread_stat = NULL;
1284 1285 _thread_stat = new ThreadStatistics();
1285 1286 _blocked_on_compilation = false;
1286 1287 _jni_active_critical = 0;
1287 1288 _do_not_unlock_if_synchronized = false;
1288 1289 _cached_monitor_info = NULL;
1289 1290 _parker = Parker::Allocate(this) ;
1290 1291
1291 1292 #ifndef PRODUCT
1292 1293 _jmp_ring_index = 0;
1293 1294 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1294 1295 record_jump(NULL, NULL, NULL, 0);
1295 1296 }
1296 1297 #endif /* PRODUCT */
1297 1298
1298 1299 set_thread_profiler(NULL);
1299 1300 if (FlatProfiler::is_active()) {
1300 1301 // This is where we would decide to either give each thread it's own profiler
1301 1302 // or use one global one from FlatProfiler,
1302 1303 // or up to some count of the number of profiled threads, etc.
1303 1304 ThreadProfiler* pp = new ThreadProfiler();
1304 1305 pp->engage();
1305 1306 set_thread_profiler(pp);
1306 1307 }
1307 1308
1308 1309 // Setup safepoint state info for this thread
1309 1310 ThreadSafepointState::create(this);
1310 1311
1311 1312 debug_only(_java_call_counter = 0);
1312 1313
1313 1314 // JVMTI PopFrame support
1314 1315 _popframe_condition = popframe_inactive;
1315 1316 _popframe_preserved_args = NULL;
1316 1317 _popframe_preserved_args_size = 0;
1317 1318
1318 1319 pd_initialize();
1319 1320 }
1320 1321
1321 1322 #ifndef SERIALGC
1322 1323 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1323 1324 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1324 1325 #endif // !SERIALGC
1325 1326
1326 1327 JavaThread::JavaThread(bool is_attaching) :
1327 1328 Thread()
1328 1329 #ifndef SERIALGC
1329 1330 , _satb_mark_queue(&_satb_mark_queue_set),
1330 1331 _dirty_card_queue(&_dirty_card_queue_set)
1331 1332 #endif // !SERIALGC
1332 1333 {
1333 1334 initialize();
1334 1335 _is_attaching = is_attaching;
1335 1336 assert(_deferred_card_mark.is_empty(), "Default MemRegion ctor");
1336 1337 }
1337 1338
1338 1339 bool JavaThread::reguard_stack(address cur_sp) {
1339 1340 if (_stack_guard_state != stack_guard_yellow_disabled) {
1340 1341 return true; // Stack already guarded or guard pages not needed.
1341 1342 }
1342 1343
1343 1344 if (register_stack_overflow()) {
1344 1345 // For those architectures which have separate register and
1345 1346 // memory stacks, we must check the register stack to see if
1346 1347 // it has overflowed.
1347 1348 return false;
1348 1349 }
1349 1350
1350 1351 // Java code never executes within the yellow zone: the latter is only
1351 1352 // there to provoke an exception during stack banging. If java code
1352 1353 // is executing there, either StackShadowPages should be larger, or
1353 1354 // some exception code in c1, c2 or the interpreter isn't unwinding
1354 1355 // when it should.
1355 1356 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1356 1357
1357 1358 enable_stack_yellow_zone();
1358 1359 return true;
1359 1360 }
1360 1361
1361 1362 bool JavaThread::reguard_stack(void) {
1362 1363 return reguard_stack(os::current_stack_pointer());
1363 1364 }
1364 1365
1365 1366
1366 1367 void JavaThread::block_if_vm_exited() {
1367 1368 if (_terminated == _vm_exited) {
1368 1369 // _vm_exited is set at safepoint, and Threads_lock is never released
1369 1370 // we will block here forever
1370 1371 Threads_lock->lock_without_safepoint_check();
1371 1372 ShouldNotReachHere();
1372 1373 }
1373 1374 }
1374 1375
1375 1376
1376 1377 // Remove this ifdef when C1 is ported to the compiler interface.
1377 1378 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1378 1379
1379 1380 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1380 1381 Thread()
1381 1382 #ifndef SERIALGC
1382 1383 , _satb_mark_queue(&_satb_mark_queue_set),
1383 1384 _dirty_card_queue(&_dirty_card_queue_set)
1384 1385 #endif // !SERIALGC
1385 1386 {
1386 1387 if (TraceThreadEvents) {
1387 1388 tty->print_cr("creating thread %p", this);
1388 1389 }
1389 1390 initialize();
1390 1391 _is_attaching = false;
1391 1392 set_entry_point(entry_point);
1392 1393 // Create the native thread itself.
1393 1394 // %note runtime_23
1394 1395 os::ThreadType thr_type = os::java_thread;
1395 1396 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1396 1397 os::java_thread;
1397 1398 os::create_thread(this, thr_type, stack_sz);
1398 1399
1399 1400 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1400 1401 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1401 1402 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1402 1403 // the exception consists of creating the exception object & initializing it, initialization
1403 1404 // will leave the VM via a JavaCall and then all locks must be unlocked).
1404 1405 //
1405 1406 // The thread is still suspended when we reach here. Thread must be explicit started
1406 1407 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1407 1408 // by calling Threads:add. The reason why this is not done here, is because the thread
1408 1409 // object must be fully initialized (take a look at JVM_Start)
1409 1410 }
1410 1411
1411 1412 JavaThread::~JavaThread() {
1412 1413 if (TraceThreadEvents) {
1413 1414 tty->print_cr("terminate thread %p", this);
1414 1415 }
1415 1416
1416 1417 // JSR166 -- return the parker to the free list
1417 1418 Parker::Release(_parker);
1418 1419 _parker = NULL ;
1419 1420
1420 1421 // Free any remaining previous UnrollBlock
1421 1422 vframeArray* old_array = vframe_array_last();
1422 1423
1423 1424 if (old_array != NULL) {
1424 1425 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1425 1426 old_array->set_unroll_block(NULL);
1426 1427 delete old_info;
1427 1428 delete old_array;
1428 1429 }
1429 1430
1430 1431 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1431 1432 if (deferred != NULL) {
1432 1433 // This can only happen if thread is destroyed before deoptimization occurs.
1433 1434 assert(deferred->length() != 0, "empty array!");
1434 1435 do {
1435 1436 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1436 1437 deferred->remove_at(0);
1437 1438 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1438 1439 delete dlv;
1439 1440 } while (deferred->length() != 0);
1440 1441 delete deferred;
1441 1442 }
1442 1443
1443 1444 // All Java related clean up happens in exit
1444 1445 ThreadSafepointState::destroy(this);
1445 1446 if (_thread_profiler != NULL) delete _thread_profiler;
1446 1447 if (_thread_stat != NULL) delete _thread_stat;
1447 1448 }
1448 1449
1449 1450
1450 1451 // The first routine called by a new Java thread
1451 1452 void JavaThread::run() {
1452 1453 // initialize thread-local alloc buffer related fields
1453 1454 this->initialize_tlab();
1454 1455
1455 1456 // used to test validitity of stack trace backs
1456 1457 this->record_base_of_stack_pointer();
1457 1458
1458 1459 // Record real stack base and size.
1459 1460 this->record_stack_base_and_size();
1460 1461
1461 1462 // Initialize thread local storage; set before calling MutexLocker
1462 1463 this->initialize_thread_local_storage();
1463 1464
1464 1465 this->create_stack_guard_pages();
1465 1466
1466 1467 this->cache_global_variables();
1467 1468
1468 1469 // Thread is now sufficient initialized to be handled by the safepoint code as being
1469 1470 // in the VM. Change thread state from _thread_new to _thread_in_vm
1470 1471 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1471 1472
1472 1473 assert(JavaThread::current() == this, "sanity check");
1473 1474 assert(!Thread::current()->owns_locks(), "sanity check");
1474 1475
1475 1476 DTRACE_THREAD_PROBE(start, this);
1476 1477
1477 1478 // This operation might block. We call that after all safepoint checks for a new thread has
1478 1479 // been completed.
1479 1480 this->set_active_handles(JNIHandleBlock::allocate_block());
1480 1481
1481 1482 if (JvmtiExport::should_post_thread_life()) {
1482 1483 JvmtiExport::post_thread_start(this);
1483 1484 }
1484 1485
1485 1486 // We call another function to do the rest so we are sure that the stack addresses used
1486 1487 // from there will be lower than the stack base just computed
1487 1488 thread_main_inner();
1488 1489
1489 1490 // Note, thread is no longer valid at this point!
1490 1491 }
1491 1492
1492 1493
1493 1494 void JavaThread::thread_main_inner() {
1494 1495 assert(JavaThread::current() == this, "sanity check");
1495 1496 assert(this->threadObj() != NULL, "just checking");
1496 1497
1497 1498 // Execute thread entry point unless this thread has a pending exception
1498 1499 // or has been stopped before starting.
1499 1500 // Note: Due to JVM_StopThread we can have pending exceptions already!
1500 1501 if (!this->has_pending_exception() &&
1501 1502 !java_lang_Thread::is_stillborn(this->threadObj())) {
1502 1503 HandleMark hm(this);
1503 1504 this->entry_point()(this, this);
1504 1505 }
1505 1506
1506 1507 DTRACE_THREAD_PROBE(stop, this);
1507 1508
1508 1509 this->exit(false);
1509 1510 delete this;
1510 1511 }
1511 1512
1512 1513
1513 1514 static void ensure_join(JavaThread* thread) {
1514 1515 // We do not need to grap the Threads_lock, since we are operating on ourself.
1515 1516 Handle threadObj(thread, thread->threadObj());
1516 1517 assert(threadObj.not_null(), "java thread object must exist");
1517 1518 ObjectLocker lock(threadObj, thread);
1518 1519 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1519 1520 thread->clear_pending_exception();
1520 1521 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1521 1522 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1522 1523 // Clear the native thread instance - this makes isAlive return false and allows the join()
1523 1524 // to complete once we've done the notify_all below
1524 1525 java_lang_Thread::set_thread(threadObj(), NULL);
1525 1526 lock.notify_all(thread);
1526 1527 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1527 1528 thread->clear_pending_exception();
1528 1529 }
1529 1530
1530 1531
1531 1532 // For any new cleanup additions, please check to see if they need to be applied to
1532 1533 // cleanup_failed_attach_current_thread as well.
1533 1534 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1534 1535 assert(this == JavaThread::current(), "thread consistency check");
1535 1536 if (!InitializeJavaLangSystem) return;
1536 1537
1537 1538 HandleMark hm(this);
1538 1539 Handle uncaught_exception(this, this->pending_exception());
1539 1540 this->clear_pending_exception();
1540 1541 Handle threadObj(this, this->threadObj());
1541 1542 assert(threadObj.not_null(), "Java thread object should be created");
1542 1543
1543 1544 if (get_thread_profiler() != NULL) {
1544 1545 get_thread_profiler()->disengage();
1545 1546 ResourceMark rm;
1546 1547 get_thread_profiler()->print(get_thread_name());
1547 1548 }
1548 1549
1549 1550
1550 1551 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1551 1552 {
1552 1553 EXCEPTION_MARK;
1553 1554
1554 1555 CLEAR_PENDING_EXCEPTION;
1555 1556 }
1556 1557 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1557 1558 // has to be fixed by a runtime query method
1558 1559 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1559 1560 // JSR-166: change call from from ThreadGroup.uncaughtException to
1560 1561 // java.lang.Thread.dispatchUncaughtException
1561 1562 if (uncaught_exception.not_null()) {
1562 1563 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1563 1564 Events::log("uncaught exception INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT",
1564 1565 (address)uncaught_exception(), (address)threadObj(), (address)group());
1565 1566 {
1566 1567 EXCEPTION_MARK;
1567 1568 // Check if the method Thread.dispatchUncaughtException() exists. If so
1568 1569 // call it. Otherwise we have an older library without the JSR-166 changes,
1569 1570 // so call ThreadGroup.uncaughtException()
1570 1571 KlassHandle recvrKlass(THREAD, threadObj->klass());
1571 1572 CallInfo callinfo;
1572 1573 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1573 1574 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1574 1575 vmSymbols::dispatchUncaughtException_name(),
1575 1576 vmSymbols::throwable_void_signature(),
1576 1577 KlassHandle(), false, false, THREAD);
1577 1578 CLEAR_PENDING_EXCEPTION;
1578 1579 methodHandle method = callinfo.selected_method();
1579 1580 if (method.not_null()) {
1580 1581 JavaValue result(T_VOID);
1581 1582 JavaCalls::call_virtual(&result,
1582 1583 threadObj, thread_klass,
1583 1584 vmSymbols::dispatchUncaughtException_name(),
1584 1585 vmSymbols::throwable_void_signature(),
1585 1586 uncaught_exception,
1586 1587 THREAD);
1587 1588 } else {
1588 1589 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1589 1590 JavaValue result(T_VOID);
1590 1591 JavaCalls::call_virtual(&result,
1591 1592 group, thread_group,
1592 1593 vmSymbols::uncaughtException_name(),
1593 1594 vmSymbols::thread_throwable_void_signature(),
1594 1595 threadObj, // Arg 1
1595 1596 uncaught_exception, // Arg 2
1596 1597 THREAD);
1597 1598 }
1598 1599 if (HAS_PENDING_EXCEPTION) {
1599 1600 ResourceMark rm(this);
1600 1601 jio_fprintf(defaultStream::error_stream(),
1601 1602 "\nException: %s thrown from the UncaughtExceptionHandler"
1602 1603 " in thread \"%s\"\n",
1603 1604 Klass::cast(pending_exception()->klass())->external_name(),
1604 1605 get_thread_name());
1605 1606 CLEAR_PENDING_EXCEPTION;
1606 1607 }
1607 1608 }
1608 1609 }
1609 1610
1610 1611 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1611 1612 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1612 1613 // is deprecated anyhow.
1613 1614 { int count = 3;
1614 1615 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1615 1616 EXCEPTION_MARK;
1616 1617 JavaValue result(T_VOID);
1617 1618 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1618 1619 JavaCalls::call_virtual(&result,
1619 1620 threadObj, thread_klass,
1620 1621 vmSymbols::exit_method_name(),
1621 1622 vmSymbols::void_method_signature(),
1622 1623 THREAD);
1623 1624 CLEAR_PENDING_EXCEPTION;
1624 1625 }
1625 1626 }
1626 1627
1627 1628 // notify JVMTI
1628 1629 if (JvmtiExport::should_post_thread_life()) {
1629 1630 JvmtiExport::post_thread_end(this);
1630 1631 }
1631 1632
1632 1633 // We have notified the agents that we are exiting, before we go on,
1633 1634 // we must check for a pending external suspend request and honor it
1634 1635 // in order to not surprise the thread that made the suspend request.
1635 1636 while (true) {
1636 1637 {
1637 1638 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1638 1639 if (!is_external_suspend()) {
1639 1640 set_terminated(_thread_exiting);
1640 1641 ThreadService::current_thread_exiting(this);
1641 1642 break;
1642 1643 }
1643 1644 // Implied else:
1644 1645 // Things get a little tricky here. We have a pending external
1645 1646 // suspend request, but we are holding the SR_lock so we
1646 1647 // can't just self-suspend. So we temporarily drop the lock
1647 1648 // and then self-suspend.
1648 1649 }
1649 1650
1650 1651 ThreadBlockInVM tbivm(this);
1651 1652 java_suspend_self();
1652 1653
1653 1654 // We're done with this suspend request, but we have to loop around
1654 1655 // and check again. Eventually we will get SR_lock without a pending
1655 1656 // external suspend request and will be able to mark ourselves as
1656 1657 // exiting.
1657 1658 }
1658 1659 // no more external suspends are allowed at this point
1659 1660 } else {
1660 1661 // before_exit() has already posted JVMTI THREAD_END events
1661 1662 }
1662 1663
1663 1664 // Notify waiters on thread object. This has to be done after exit() is called
1664 1665 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1665 1666 // group should have the destroyed bit set before waiters are notified).
1666 1667 ensure_join(this);
1667 1668 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1668 1669
1669 1670 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1670 1671 // held by this thread must be released. A detach operation must only
1671 1672 // get here if there are no Java frames on the stack. Therefore, any
1672 1673 // owned monitors at this point MUST be JNI-acquired monitors which are
1673 1674 // pre-inflated and in the monitor cache.
1674 1675 //
1675 1676 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1676 1677 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1677 1678 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1678 1679 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1679 1680 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1680 1681 }
1681 1682
1682 1683 // These things needs to be done while we are still a Java Thread. Make sure that thread
1683 1684 // is in a consistent state, in case GC happens
1684 1685 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1685 1686
1686 1687 if (active_handles() != NULL) {
1687 1688 JNIHandleBlock* block = active_handles();
1688 1689 set_active_handles(NULL);
1689 1690 JNIHandleBlock::release_block(block);
1690 1691 }
1691 1692
1692 1693 if (free_handle_block() != NULL) {
1693 1694 JNIHandleBlock* block = free_handle_block();
1694 1695 set_free_handle_block(NULL);
1695 1696 JNIHandleBlock::release_block(block);
1696 1697 }
1697 1698
1698 1699 // These have to be removed while this is still a valid thread.
1699 1700 remove_stack_guard_pages();
1700 1701
1701 1702 if (UseTLAB) {
1702 1703 tlab().make_parsable(true); // retire TLAB
1703 1704 }
1704 1705
1705 1706 if (JvmtiEnv::environments_might_exist()) {
1706 1707 JvmtiExport::cleanup_thread(this);
1707 1708 }
1708 1709
1709 1710 #ifndef SERIALGC
1710 1711 // We must flush G1-related buffers before removing a thread from
1711 1712 // the list of active threads.
1712 1713 if (UseG1GC) {
1713 1714 flush_barrier_queues();
1714 1715 }
1715 1716 #endif
1716 1717
1717 1718 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1718 1719 Threads::remove(this);
1719 1720 }
1720 1721
1721 1722 #ifndef SERIALGC
1722 1723 // Flush G1-related queues.
1723 1724 void JavaThread::flush_barrier_queues() {
1724 1725 satb_mark_queue().flush();
1725 1726 dirty_card_queue().flush();
1726 1727 }
1727 1728
1728 1729 void JavaThread::initialize_queues() {
1729 1730 assert(!SafepointSynchronize::is_at_safepoint(),
1730 1731 "we should not be at a safepoint");
1731 1732
1732 1733 ObjPtrQueue& satb_queue = satb_mark_queue();
1733 1734 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1734 1735 // The SATB queue should have been constructed with its active
1735 1736 // field set to false.
1736 1737 assert(!satb_queue.is_active(), "SATB queue should not be active");
1737 1738 assert(satb_queue.is_empty(), "SATB queue should be empty");
1738 1739 // If we are creating the thread during a marking cycle, we should
1739 1740 // set the active field of the SATB queue to true.
1740 1741 if (satb_queue_set.is_active()) {
1741 1742 satb_queue.set_active(true);
1742 1743 }
1743 1744
1744 1745 DirtyCardQueue& dirty_queue = dirty_card_queue();
1745 1746 // The dirty card queue should have been constructed with its
1746 1747 // active field set to true.
1747 1748 assert(dirty_queue.is_active(), "dirty card queue should be active");
1748 1749 }
1749 1750 #endif // !SERIALGC
1750 1751
1751 1752 void JavaThread::cleanup_failed_attach_current_thread() {
1752 1753 if (get_thread_profiler() != NULL) {
1753 1754 get_thread_profiler()->disengage();
1754 1755 ResourceMark rm;
1755 1756 get_thread_profiler()->print(get_thread_name());
1756 1757 }
1757 1758
1758 1759 if (active_handles() != NULL) {
1759 1760 JNIHandleBlock* block = active_handles();
1760 1761 set_active_handles(NULL);
1761 1762 JNIHandleBlock::release_block(block);
1762 1763 }
1763 1764
1764 1765 if (free_handle_block() != NULL) {
1765 1766 JNIHandleBlock* block = free_handle_block();
1766 1767 set_free_handle_block(NULL);
1767 1768 JNIHandleBlock::release_block(block);
1768 1769 }
1769 1770
1770 1771 // These have to be removed while this is still a valid thread.
1771 1772 remove_stack_guard_pages();
1772 1773
1773 1774 if (UseTLAB) {
1774 1775 tlab().make_parsable(true); // retire TLAB, if any
1775 1776 }
1776 1777
1777 1778 #ifndef SERIALGC
1778 1779 if (UseG1GC) {
1779 1780 flush_barrier_queues();
1780 1781 }
1781 1782 #endif
1782 1783
1783 1784 Threads::remove(this);
1784 1785 delete this;
1785 1786 }
1786 1787
1787 1788
1788 1789
1789 1790
1790 1791 JavaThread* JavaThread::active() {
1791 1792 Thread* thread = ThreadLocalStorage::thread();
1792 1793 assert(thread != NULL, "just checking");
1793 1794 if (thread->is_Java_thread()) {
1794 1795 return (JavaThread*) thread;
1795 1796 } else {
1796 1797 assert(thread->is_VM_thread(), "this must be a vm thread");
1797 1798 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1798 1799 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1799 1800 assert(ret->is_Java_thread(), "must be a Java thread");
1800 1801 return ret;
1801 1802 }
1802 1803 }
1803 1804
1804 1805 bool JavaThread::is_lock_owned(address adr) const {
1805 1806 if (Thread::is_lock_owned(adr)) return true;
1806 1807
1807 1808 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1808 1809 if (chunk->contains(adr)) return true;
1809 1810 }
1810 1811
1811 1812 return false;
1812 1813 }
1813 1814
1814 1815
1815 1816 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1816 1817 chunk->set_next(monitor_chunks());
1817 1818 set_monitor_chunks(chunk);
1818 1819 }
1819 1820
1820 1821 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1821 1822 guarantee(monitor_chunks() != NULL, "must be non empty");
1822 1823 if (monitor_chunks() == chunk) {
1823 1824 set_monitor_chunks(chunk->next());
1824 1825 } else {
1825 1826 MonitorChunk* prev = monitor_chunks();
1826 1827 while (prev->next() != chunk) prev = prev->next();
1827 1828 prev->set_next(chunk->next());
1828 1829 }
1829 1830 }
1830 1831
1831 1832 // JVM support.
1832 1833
1833 1834 // Note: this function shouldn't block if it's called in
1834 1835 // _thread_in_native_trans state (such as from
1835 1836 // check_special_condition_for_native_trans()).
1836 1837 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1837 1838
1838 1839 if (has_last_Java_frame() && has_async_condition()) {
1839 1840 // If we are at a polling page safepoint (not a poll return)
1840 1841 // then we must defer async exception because live registers
1841 1842 // will be clobbered by the exception path. Poll return is
1842 1843 // ok because the call we a returning from already collides
1843 1844 // with exception handling registers and so there is no issue.
1844 1845 // (The exception handling path kills call result registers but
1845 1846 // this is ok since the exception kills the result anyway).
1846 1847
1847 1848 if (is_at_poll_safepoint()) {
1848 1849 // if the code we are returning to has deoptimized we must defer
1849 1850 // the exception otherwise live registers get clobbered on the
1850 1851 // exception path before deoptimization is able to retrieve them.
1851 1852 //
1852 1853 RegisterMap map(this, false);
1853 1854 frame caller_fr = last_frame().sender(&map);
1854 1855 assert(caller_fr.is_compiled_frame(), "what?");
1855 1856 if (caller_fr.is_deoptimized_frame()) {
1856 1857 if (TraceExceptions) {
1857 1858 ResourceMark rm;
1858 1859 tty->print_cr("deferred async exception at compiled safepoint");
1859 1860 }
1860 1861 return;
1861 1862 }
1862 1863 }
1863 1864 }
1864 1865
1865 1866 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
1866 1867 if (condition == _no_async_condition) {
1867 1868 // Conditions have changed since has_special_runtime_exit_condition()
1868 1869 // was called:
1869 1870 // - if we were here only because of an external suspend request,
1870 1871 // then that was taken care of above (or cancelled) so we are done
1871 1872 // - if we were here because of another async request, then it has
1872 1873 // been cleared between the has_special_runtime_exit_condition()
1873 1874 // and now so again we are done
1874 1875 return;
1875 1876 }
1876 1877
1877 1878 // Check for pending async. exception
1878 1879 if (_pending_async_exception != NULL) {
1879 1880 // Only overwrite an already pending exception, if it is not a threadDeath.
1880 1881 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
1881 1882
1882 1883 // We cannot call Exceptions::_throw(...) here because we cannot block
1883 1884 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
1884 1885
1885 1886 if (TraceExceptions) {
1886 1887 ResourceMark rm;
1887 1888 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
1888 1889 if (has_last_Java_frame() ) {
1889 1890 frame f = last_frame();
1890 1891 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
1891 1892 }
1892 1893 tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
1893 1894 }
1894 1895 _pending_async_exception = NULL;
1895 1896 clear_has_async_exception();
1896 1897 }
1897 1898 }
1898 1899
1899 1900 if (check_unsafe_error &&
1900 1901 condition == _async_unsafe_access_error && !has_pending_exception()) {
1901 1902 condition = _no_async_condition; // done
1902 1903 switch (thread_state()) {
1903 1904 case _thread_in_vm:
1904 1905 {
1905 1906 JavaThread* THREAD = this;
1906 1907 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1907 1908 }
1908 1909 case _thread_in_native:
1909 1910 {
1910 1911 ThreadInVMfromNative tiv(this);
1911 1912 JavaThread* THREAD = this;
1912 1913 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1913 1914 }
1914 1915 case _thread_in_Java:
1915 1916 {
1916 1917 ThreadInVMfromJava tiv(this);
1917 1918 JavaThread* THREAD = this;
1918 1919 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
1919 1920 }
1920 1921 default:
1921 1922 ShouldNotReachHere();
1922 1923 }
1923 1924 }
1924 1925
1925 1926 assert(condition == _no_async_condition || has_pending_exception() ||
1926 1927 (!check_unsafe_error && condition == _async_unsafe_access_error),
1927 1928 "must have handled the async condition, if no exception");
1928 1929 }
1929 1930
1930 1931 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
1931 1932 //
1932 1933 // Check for pending external suspend. Internal suspend requests do
1933 1934 // not use handle_special_runtime_exit_condition().
1934 1935 // If JNIEnv proxies are allowed, don't self-suspend if the target
1935 1936 // thread is not the current thread. In older versions of jdbx, jdbx
1936 1937 // threads could call into the VM with another thread's JNIEnv so we
1937 1938 // can be here operating on behalf of a suspended thread (4432884).
1938 1939 bool do_self_suspend = is_external_suspend_with_lock();
1939 1940 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
1940 1941 //
1941 1942 // Because thread is external suspended the safepoint code will count
1942 1943 // thread as at a safepoint. This can be odd because we can be here
1943 1944 // as _thread_in_Java which would normally transition to _thread_blocked
1944 1945 // at a safepoint. We would like to mark the thread as _thread_blocked
1945 1946 // before calling java_suspend_self like all other callers of it but
1946 1947 // we must then observe proper safepoint protocol. (We can't leave
1947 1948 // _thread_blocked with a safepoint in progress). However we can be
1948 1949 // here as _thread_in_native_trans so we can't use a normal transition
1949 1950 // constructor/destructor pair because they assert on that type of
1950 1951 // transition. We could do something like:
1951 1952 //
1952 1953 // JavaThreadState state = thread_state();
1953 1954 // set_thread_state(_thread_in_vm);
1954 1955 // {
1955 1956 // ThreadBlockInVM tbivm(this);
1956 1957 // java_suspend_self()
1957 1958 // }
1958 1959 // set_thread_state(_thread_in_vm_trans);
1959 1960 // if (safepoint) block;
1960 1961 // set_thread_state(state);
1961 1962 //
1962 1963 // but that is pretty messy. Instead we just go with the way the
1963 1964 // code has worked before and note that this is the only path to
1964 1965 // java_suspend_self that doesn't put the thread in _thread_blocked
1965 1966 // mode.
1966 1967
1967 1968 frame_anchor()->make_walkable(this);
1968 1969 java_suspend_self();
1969 1970
1970 1971 // We might be here for reasons in addition to the self-suspend request
1971 1972 // so check for other async requests.
1972 1973 }
1973 1974
1974 1975 if (check_asyncs) {
1975 1976 check_and_handle_async_exceptions();
1976 1977 }
1977 1978 }
1978 1979
1979 1980 void JavaThread::send_thread_stop(oop java_throwable) {
1980 1981 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
1981 1982 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
1982 1983 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
1983 1984
1984 1985 // Do not throw asynchronous exceptions against the compiler thread
1985 1986 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
1986 1987 if (is_Compiler_thread()) return;
1987 1988
1988 1989 {
1989 1990 // Actually throw the Throwable against the target Thread - however
1990 1991 // only if there is no thread death exception installed already.
1991 1992 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
1992 1993 // If the topmost frame is a runtime stub, then we are calling into
1993 1994 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1994 1995 // must deoptimize the caller before continuing, as the compiled exception handler table
1995 1996 // may not be valid
1996 1997 if (has_last_Java_frame()) {
1997 1998 frame f = last_frame();
1998 1999 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
1999 2000 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2000 2001 RegisterMap reg_map(this, UseBiasedLocking);
2001 2002 frame compiled_frame = f.sender(®_map);
2002 2003 if (compiled_frame.can_be_deoptimized()) {
2003 2004 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2004 2005 }
2005 2006 }
2006 2007 }
2007 2008
2008 2009 // Set async. pending exception in thread.
2009 2010 set_pending_async_exception(java_throwable);
2010 2011
2011 2012 if (TraceExceptions) {
2012 2013 ResourceMark rm;
2013 2014 tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
2014 2015 }
2015 2016 // for AbortVMOnException flag
2016 2017 NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name()));
2017 2018 }
2018 2019 }
2019 2020
2020 2021
2021 2022 // Interrupt thread so it will wake up from a potential wait()
2022 2023 Thread::interrupt(this);
2023 2024 }
2024 2025
2025 2026 // External suspension mechanism.
2026 2027 //
2027 2028 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2028 2029 // to any VM_locks and it is at a transition
2029 2030 // Self-suspension will happen on the transition out of the vm.
2030 2031 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2031 2032 //
2032 2033 // Guarantees on return:
2033 2034 // + Target thread will not execute any new bytecode (that's why we need to
2034 2035 // force a safepoint)
2035 2036 // + Target thread will not enter any new monitors
2036 2037 //
2037 2038 void JavaThread::java_suspend() {
2038 2039 { MutexLocker mu(Threads_lock);
2039 2040 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2040 2041 return;
2041 2042 }
2042 2043 }
2043 2044
2044 2045 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2045 2046 if (!is_external_suspend()) {
2046 2047 // a racing resume has cancelled us; bail out now
2047 2048 return;
2048 2049 }
2049 2050
2050 2051 // suspend is done
2051 2052 uint32_t debug_bits = 0;
2052 2053 // Warning: is_ext_suspend_completed() may temporarily drop the
2053 2054 // SR_lock to allow the thread to reach a stable thread state if
2054 2055 // it is currently in a transient thread state.
2055 2056 if (is_ext_suspend_completed(false /* !called_by_wait */,
2056 2057 SuspendRetryDelay, &debug_bits) ) {
2057 2058 return;
2058 2059 }
2059 2060 }
2060 2061
2061 2062 VM_ForceSafepoint vm_suspend;
2062 2063 VMThread::execute(&vm_suspend);
2063 2064 }
2064 2065
2065 2066 // Part II of external suspension.
2066 2067 // A JavaThread self suspends when it detects a pending external suspend
2067 2068 // request. This is usually on transitions. It is also done in places
2068 2069 // where continuing to the next transition would surprise the caller,
2069 2070 // e.g., monitor entry.
2070 2071 //
2071 2072 // Returns the number of times that the thread self-suspended.
2072 2073 //
2073 2074 // Note: DO NOT call java_suspend_self() when you just want to block current
2074 2075 // thread. java_suspend_self() is the second stage of cooperative
2075 2076 // suspension for external suspend requests and should only be used
2076 2077 // to complete an external suspend request.
2077 2078 //
2078 2079 int JavaThread::java_suspend_self() {
2079 2080 int ret = 0;
2080 2081
2081 2082 // we are in the process of exiting so don't suspend
2082 2083 if (is_exiting()) {
2083 2084 clear_external_suspend();
2084 2085 return ret;
2085 2086 }
2086 2087
2087 2088 assert(_anchor.walkable() ||
2088 2089 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2089 2090 "must have walkable stack");
2090 2091
2091 2092 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2092 2093
2093 2094 assert(!this->is_ext_suspended(),
2094 2095 "a thread trying to self-suspend should not already be suspended");
2095 2096
2096 2097 if (this->is_suspend_equivalent()) {
2097 2098 // If we are self-suspending as a result of the lifting of a
2098 2099 // suspend equivalent condition, then the suspend_equivalent
2099 2100 // flag is not cleared until we set the ext_suspended flag so
2100 2101 // that wait_for_ext_suspend_completion() returns consistent
2101 2102 // results.
2102 2103 this->clear_suspend_equivalent();
2103 2104 }
2104 2105
2105 2106 // A racing resume may have cancelled us before we grabbed SR_lock
2106 2107 // above. Or another external suspend request could be waiting for us
2107 2108 // by the time we return from SR_lock()->wait(). The thread
2108 2109 // that requested the suspension may already be trying to walk our
2109 2110 // stack and if we return now, we can change the stack out from under
2110 2111 // it. This would be a "bad thing (TM)" and cause the stack walker
2111 2112 // to crash. We stay self-suspended until there are no more pending
2112 2113 // external suspend requests.
2113 2114 while (is_external_suspend()) {
2114 2115 ret++;
2115 2116 this->set_ext_suspended();
2116 2117
2117 2118 // _ext_suspended flag is cleared by java_resume()
2118 2119 while (is_ext_suspended()) {
2119 2120 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2120 2121 }
2121 2122 }
2122 2123
2123 2124 return ret;
2124 2125 }
2125 2126
2126 2127 #ifdef ASSERT
2127 2128 // verify the JavaThread has not yet been published in the Threads::list, and
2128 2129 // hence doesn't need protection from concurrent access at this stage
2129 2130 void JavaThread::verify_not_published() {
2130 2131 if (!Threads_lock->owned_by_self()) {
2131 2132 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2132 2133 assert( !Threads::includes(this),
2133 2134 "java thread shouldn't have been published yet!");
2134 2135 }
2135 2136 else {
2136 2137 assert( !Threads::includes(this),
2137 2138 "java thread shouldn't have been published yet!");
2138 2139 }
2139 2140 }
2140 2141 #endif
2141 2142
2142 2143 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2143 2144 // progress or when _suspend_flags is non-zero.
2144 2145 // Current thread needs to self-suspend if there is a suspend request and/or
2145 2146 // block if a safepoint is in progress.
2146 2147 // Async exception ISN'T checked.
2147 2148 // Note only the ThreadInVMfromNative transition can call this function
2148 2149 // directly and when thread state is _thread_in_native_trans
2149 2150 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2150 2151 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2151 2152
2152 2153 JavaThread *curJT = JavaThread::current();
2153 2154 bool do_self_suspend = thread->is_external_suspend();
2154 2155
2155 2156 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2156 2157
2157 2158 // If JNIEnv proxies are allowed, don't self-suspend if the target
2158 2159 // thread is not the current thread. In older versions of jdbx, jdbx
2159 2160 // threads could call into the VM with another thread's JNIEnv so we
2160 2161 // can be here operating on behalf of a suspended thread (4432884).
2161 2162 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2162 2163 JavaThreadState state = thread->thread_state();
2163 2164
2164 2165 // We mark this thread_blocked state as a suspend-equivalent so
2165 2166 // that a caller to is_ext_suspend_completed() won't be confused.
2166 2167 // The suspend-equivalent state is cleared by java_suspend_self().
2167 2168 thread->set_suspend_equivalent();
2168 2169
2169 2170 // If the safepoint code sees the _thread_in_native_trans state, it will
2170 2171 // wait until the thread changes to other thread state. There is no
2171 2172 // guarantee on how soon we can obtain the SR_lock and complete the
2172 2173 // self-suspend request. It would be a bad idea to let safepoint wait for
2173 2174 // too long. Temporarily change the state to _thread_blocked to
2174 2175 // let the VM thread know that this thread is ready for GC. The problem
2175 2176 // of changing thread state is that safepoint could happen just after
2176 2177 // java_suspend_self() returns after being resumed, and VM thread will
2177 2178 // see the _thread_blocked state. We must check for safepoint
2178 2179 // after restoring the state and make sure we won't leave while a safepoint
2179 2180 // is in progress.
2180 2181 thread->set_thread_state(_thread_blocked);
2181 2182 thread->java_suspend_self();
2182 2183 thread->set_thread_state(state);
2183 2184 // Make sure new state is seen by VM thread
2184 2185 if (os::is_MP()) {
2185 2186 if (UseMembar) {
2186 2187 // Force a fence between the write above and read below
2187 2188 OrderAccess::fence();
2188 2189 } else {
2189 2190 // Must use this rather than serialization page in particular on Windows
2190 2191 InterfaceSupport::serialize_memory(thread);
2191 2192 }
2192 2193 }
2193 2194 }
2194 2195
2195 2196 if (SafepointSynchronize::do_call_back()) {
2196 2197 // If we are safepointing, then block the caller which may not be
2197 2198 // the same as the target thread (see above).
2198 2199 SafepointSynchronize::block(curJT);
2199 2200 }
2200 2201
2201 2202 if (thread->is_deopt_suspend()) {
2202 2203 thread->clear_deopt_suspend();
2203 2204 RegisterMap map(thread, false);
2204 2205 frame f = thread->last_frame();
2205 2206 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2206 2207 f = f.sender(&map);
2207 2208 }
2208 2209 if (f.id() == thread->must_deopt_id()) {
2209 2210 thread->clear_must_deopt_id();
2210 2211 f.deoptimize(thread);
2211 2212 } else {
2212 2213 fatal("missed deoptimization!");
2213 2214 }
2214 2215 }
2215 2216 }
2216 2217
2217 2218 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2218 2219 // progress or when _suspend_flags is non-zero.
2219 2220 // Current thread needs to self-suspend if there is a suspend request and/or
2220 2221 // block if a safepoint is in progress.
2221 2222 // Also check for pending async exception (not including unsafe access error).
2222 2223 // Note only the native==>VM/Java barriers can call this function and when
2223 2224 // thread state is _thread_in_native_trans.
2224 2225 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2225 2226 check_safepoint_and_suspend_for_native_trans(thread);
2226 2227
2227 2228 if (thread->has_async_exception()) {
2228 2229 // We are in _thread_in_native_trans state, don't handle unsafe
2229 2230 // access error since that may block.
2230 2231 thread->check_and_handle_async_exceptions(false);
2231 2232 }
2232 2233 }
2233 2234
2234 2235 // We need to guarantee the Threads_lock here, since resumes are not
2235 2236 // allowed during safepoint synchronization
2236 2237 // Can only resume from an external suspension
2237 2238 void JavaThread::java_resume() {
2238 2239 assert_locked_or_safepoint(Threads_lock);
2239 2240
2240 2241 // Sanity check: thread is gone, has started exiting or the thread
2241 2242 // was not externally suspended.
2242 2243 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2243 2244 return;
2244 2245 }
2245 2246
2246 2247 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2247 2248
2248 2249 clear_external_suspend();
2249 2250
2250 2251 if (is_ext_suspended()) {
2251 2252 clear_ext_suspended();
2252 2253 SR_lock()->notify_all();
2253 2254 }
2254 2255 }
2255 2256
2256 2257 void JavaThread::create_stack_guard_pages() {
2257 2258 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2258 2259 address low_addr = stack_base() - stack_size();
2259 2260 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2260 2261
2261 2262 int allocate = os::allocate_stack_guard_pages();
2262 2263 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2263 2264
2264 2265 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2265 2266 warning("Attempt to allocate stack guard pages failed.");
2266 2267 return;
2267 2268 }
2268 2269
2269 2270 if (os::guard_memory((char *) low_addr, len)) {
2270 2271 _stack_guard_state = stack_guard_enabled;
2271 2272 } else {
2272 2273 warning("Attempt to protect stack guard pages failed.");
2273 2274 if (os::uncommit_memory((char *) low_addr, len)) {
2274 2275 warning("Attempt to deallocate stack guard pages failed.");
2275 2276 }
2276 2277 }
2277 2278 }
2278 2279
2279 2280 void JavaThread::remove_stack_guard_pages() {
2280 2281 if (_stack_guard_state == stack_guard_unused) return;
2281 2282 address low_addr = stack_base() - stack_size();
2282 2283 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2283 2284
2284 2285 if (os::allocate_stack_guard_pages()) {
2285 2286 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2286 2287 _stack_guard_state = stack_guard_unused;
2287 2288 } else {
2288 2289 warning("Attempt to deallocate stack guard pages failed.");
2289 2290 }
2290 2291 } else {
2291 2292 if (_stack_guard_state == stack_guard_unused) return;
2292 2293 if (os::unguard_memory((char *) low_addr, len)) {
2293 2294 _stack_guard_state = stack_guard_unused;
2294 2295 } else {
2295 2296 warning("Attempt to unprotect stack guard pages failed.");
2296 2297 }
2297 2298 }
2298 2299 }
2299 2300
2300 2301 void JavaThread::enable_stack_yellow_zone() {
2301 2302 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2302 2303 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2303 2304
2304 2305 // The base notation is from the stacks point of view, growing downward.
2305 2306 // We need to adjust it to work correctly with guard_memory()
2306 2307 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2307 2308
2308 2309 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2309 2310 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2310 2311
2311 2312 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2312 2313 _stack_guard_state = stack_guard_enabled;
2313 2314 } else {
2314 2315 warning("Attempt to guard stack yellow zone failed.");
2315 2316 }
2316 2317 enable_register_stack_guard();
2317 2318 }
2318 2319
2319 2320 void JavaThread::disable_stack_yellow_zone() {
2320 2321 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2321 2322 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2322 2323
2323 2324 // Simply return if called for a thread that does not use guard pages.
2324 2325 if (_stack_guard_state == stack_guard_unused) return;
2325 2326
2326 2327 // The base notation is from the stacks point of view, growing downward.
2327 2328 // We need to adjust it to work correctly with guard_memory()
2328 2329 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2329 2330
2330 2331 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2331 2332 _stack_guard_state = stack_guard_yellow_disabled;
2332 2333 } else {
2333 2334 warning("Attempt to unguard stack yellow zone failed.");
2334 2335 }
2335 2336 disable_register_stack_guard();
2336 2337 }
2337 2338
2338 2339 void JavaThread::enable_stack_red_zone() {
2339 2340 // The base notation is from the stacks point of view, growing downward.
2340 2341 // We need to adjust it to work correctly with guard_memory()
2341 2342 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2342 2343 address base = stack_red_zone_base() - stack_red_zone_size();
2343 2344
2344 2345 guarantee(base < stack_base(),"Error calculating stack red zone");
2345 2346 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2346 2347
2347 2348 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2348 2349 warning("Attempt to guard stack red zone failed.");
2349 2350 }
2350 2351 }
2351 2352
2352 2353 void JavaThread::disable_stack_red_zone() {
2353 2354 // The base notation is from the stacks point of view, growing downward.
2354 2355 // We need to adjust it to work correctly with guard_memory()
2355 2356 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2356 2357 address base = stack_red_zone_base() - stack_red_zone_size();
2357 2358 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2358 2359 warning("Attempt to unguard stack red zone failed.");
2359 2360 }
2360 2361 }
2361 2362
2362 2363 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2363 2364 // ignore is there is no stack
2364 2365 if (!has_last_Java_frame()) return;
2365 2366 // traverse the stack frames. Starts from top frame.
2366 2367 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2367 2368 frame* fr = fst.current();
2368 2369 f(fr, fst.register_map());
2369 2370 }
2370 2371 }
2371 2372
2372 2373
2373 2374 #ifndef PRODUCT
2374 2375 // Deoptimization
2375 2376 // Function for testing deoptimization
2376 2377 void JavaThread::deoptimize() {
2377 2378 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2378 2379 StackFrameStream fst(this, UseBiasedLocking);
2379 2380 bool deopt = false; // Dump stack only if a deopt actually happens.
2380 2381 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2381 2382 // Iterate over all frames in the thread and deoptimize
2382 2383 for(; !fst.is_done(); fst.next()) {
2383 2384 if(fst.current()->can_be_deoptimized()) {
2384 2385
2385 2386 if (only_at) {
2386 2387 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2387 2388 // consists of comma or carriage return separated numbers so
2388 2389 // search for the current bci in that string.
2389 2390 address pc = fst.current()->pc();
2390 2391 nmethod* nm = (nmethod*) fst.current()->cb();
2391 2392 ScopeDesc* sd = nm->scope_desc_at( pc);
2392 2393 char buffer[8];
2393 2394 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2394 2395 size_t len = strlen(buffer);
2395 2396 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2396 2397 while (found != NULL) {
2397 2398 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2398 2399 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2399 2400 // Check that the bci found is bracketed by terminators.
2400 2401 break;
2401 2402 }
2402 2403 found = strstr(found + 1, buffer);
2403 2404 }
2404 2405 if (!found) {
2405 2406 continue;
2406 2407 }
2407 2408 }
2408 2409
2409 2410 if (DebugDeoptimization && !deopt) {
2410 2411 deopt = true; // One-time only print before deopt
2411 2412 tty->print_cr("[BEFORE Deoptimization]");
2412 2413 trace_frames();
2413 2414 trace_stack();
2414 2415 }
2415 2416 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2416 2417 }
2417 2418 }
2418 2419
2419 2420 if (DebugDeoptimization && deopt) {
2420 2421 tty->print_cr("[AFTER Deoptimization]");
2421 2422 trace_frames();
2422 2423 }
2423 2424 }
2424 2425
2425 2426
2426 2427 // Make zombies
2427 2428 void JavaThread::make_zombies() {
2428 2429 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2429 2430 if (fst.current()->can_be_deoptimized()) {
2430 2431 // it is a Java nmethod
2431 2432 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2432 2433 nm->make_not_entrant();
2433 2434 }
2434 2435 }
2435 2436 }
2436 2437 #endif // PRODUCT
2437 2438
2438 2439
2439 2440 void JavaThread::deoptimized_wrt_marked_nmethods() {
2440 2441 if (!has_last_Java_frame()) return;
2441 2442 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2442 2443 StackFrameStream fst(this, UseBiasedLocking);
2443 2444 for(; !fst.is_done(); fst.next()) {
2444 2445 if (fst.current()->should_be_deoptimized()) {
2445 2446 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2446 2447 }
2447 2448 }
2448 2449 }
2449 2450
2450 2451
2451 2452 // GC support
2452 2453 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2453 2454
2454 2455 void JavaThread::gc_epilogue() {
2455 2456 frames_do(frame_gc_epilogue);
2456 2457 }
2457 2458
2458 2459
2459 2460 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2460 2461
2461 2462 void JavaThread::gc_prologue() {
2462 2463 frames_do(frame_gc_prologue);
2463 2464 }
2464 2465
2465 2466 // If the caller is a NamedThread, then remember, in the current scope,
2466 2467 // the given JavaThread in its _processed_thread field.
2467 2468 class RememberProcessedThread: public StackObj {
2468 2469 NamedThread* _cur_thr;
2469 2470 public:
2470 2471 RememberProcessedThread(JavaThread* jthr) {
2471 2472 Thread* thread = Thread::current();
2472 2473 if (thread->is_Named_thread()) {
2473 2474 _cur_thr = (NamedThread *)thread;
2474 2475 _cur_thr->set_processed_thread(jthr);
2475 2476 } else {
2476 2477 _cur_thr = NULL;
2477 2478 }
2478 2479 }
2479 2480
2480 2481 ~RememberProcessedThread() {
2481 2482 if (_cur_thr) {
2482 2483 _cur_thr->set_processed_thread(NULL);
2483 2484 }
2484 2485 }
2485 2486 };
2486 2487
2487 2488 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2488 2489 // Verify that the deferred card marks have been flushed.
2489 2490 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2490 2491
2491 2492 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2492 2493 // since there may be more than one thread using each ThreadProfiler.
2493 2494
2494 2495 // Traverse the GCHandles
2495 2496 Thread::oops_do(f, cf);
2496 2497
2497 2498 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2498 2499 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2499 2500
2500 2501 if (has_last_Java_frame()) {
2501 2502 // Record JavaThread to GC thread
2502 2503 RememberProcessedThread rpt(this);
2503 2504
2504 2505 // Traverse the privileged stack
2505 2506 if (_privileged_stack_top != NULL) {
2506 2507 _privileged_stack_top->oops_do(f);
2507 2508 }
2508 2509
2509 2510 // traverse the registered growable array
2510 2511 if (_array_for_gc != NULL) {
2511 2512 for (int index = 0; index < _array_for_gc->length(); index++) {
2512 2513 f->do_oop(_array_for_gc->adr_at(index));
2513 2514 }
2514 2515 }
2515 2516
2516 2517 // Traverse the monitor chunks
2517 2518 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2518 2519 chunk->oops_do(f);
2519 2520 }
2520 2521
2521 2522 // Traverse the execution stack
2522 2523 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2523 2524 fst.current()->oops_do(f, cf, fst.register_map());
2524 2525 }
2525 2526 }
2526 2527
2527 2528 // callee_target is never live across a gc point so NULL it here should
2528 2529 // it still contain a methdOop.
2529 2530
2530 2531 set_callee_target(NULL);
2531 2532
2532 2533 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2533 2534 // If we have deferred set_locals there might be oops waiting to be
2534 2535 // written
2535 2536 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2536 2537 if (list != NULL) {
2537 2538 for (int i = 0; i < list->length(); i++) {
2538 2539 list->at(i)->oops_do(f);
2539 2540 }
2540 2541 }
2541 2542
2542 2543 // Traverse instance variables at the end since the GC may be moving things
2543 2544 // around using this function
2544 2545 f->do_oop((oop*) &_threadObj);
2545 2546 f->do_oop((oop*) &_vm_result);
2546 2547 f->do_oop((oop*) &_vm_result_2);
2547 2548 f->do_oop((oop*) &_exception_oop);
2548 2549 f->do_oop((oop*) &_pending_async_exception);
2549 2550
2550 2551 if (jvmti_thread_state() != NULL) {
2551 2552 jvmti_thread_state()->oops_do(f);
2552 2553 }
2553 2554 }
2554 2555
2555 2556 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2556 2557 Thread::nmethods_do(cf); // (super method is a no-op)
2557 2558
2558 2559 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2559 2560 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2560 2561
2561 2562 if (has_last_Java_frame()) {
2562 2563 // Traverse the execution stack
2563 2564 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2564 2565 fst.current()->nmethods_do(cf);
2565 2566 }
2566 2567 }
2567 2568 }
2568 2569
2569 2570 // Printing
2570 2571 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2571 2572 switch (_thread_state) {
2572 2573 case _thread_uninitialized: return "_thread_uninitialized";
2573 2574 case _thread_new: return "_thread_new";
2574 2575 case _thread_new_trans: return "_thread_new_trans";
2575 2576 case _thread_in_native: return "_thread_in_native";
2576 2577 case _thread_in_native_trans: return "_thread_in_native_trans";
2577 2578 case _thread_in_vm: return "_thread_in_vm";
2578 2579 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2579 2580 case _thread_in_Java: return "_thread_in_Java";
2580 2581 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2581 2582 case _thread_blocked: return "_thread_blocked";
2582 2583 case _thread_blocked_trans: return "_thread_blocked_trans";
2583 2584 default: return "unknown thread state";
2584 2585 }
2585 2586 }
2586 2587
2587 2588 #ifndef PRODUCT
2588 2589 void JavaThread::print_thread_state_on(outputStream *st) const {
2589 2590 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2590 2591 };
2591 2592 void JavaThread::print_thread_state() const {
2592 2593 print_thread_state_on(tty);
2593 2594 };
2594 2595 #endif // PRODUCT
2595 2596
2596 2597 // Called by Threads::print() for VM_PrintThreads operation
2597 2598 void JavaThread::print_on(outputStream *st) const {
2598 2599 st->print("\"%s\" ", get_thread_name());
2599 2600 oop thread_oop = threadObj();
2600 2601 if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2601 2602 Thread::print_on(st);
2602 2603 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2603 2604 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2604 2605 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2605 2606 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2606 2607 }
2607 2608 #ifndef PRODUCT
2608 2609 print_thread_state_on(st);
2609 2610 _safepoint_state->print_on(st);
2610 2611 #endif // PRODUCT
2611 2612 }
2612 2613
2613 2614 // Called by fatal error handler. The difference between this and
2614 2615 // JavaThread::print() is that we can't grab lock or allocate memory.
2615 2616 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2616 2617 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2617 2618 oop thread_obj = threadObj();
2618 2619 if (thread_obj != NULL) {
2619 2620 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2620 2621 }
2621 2622 st->print(" [");
2622 2623 st->print("%s", _get_thread_state_name(_thread_state));
2623 2624 if (osthread()) {
2624 2625 st->print(", id=%d", osthread()->thread_id());
2625 2626 }
2626 2627 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2627 2628 _stack_base - _stack_size, _stack_base);
2628 2629 st->print("]");
2629 2630 return;
2630 2631 }
2631 2632
2632 2633 // Verification
2633 2634
2634 2635 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2635 2636
2636 2637 void JavaThread::verify() {
2637 2638 // Verify oops in the thread.
2638 2639 oops_do(&VerifyOopClosure::verify_oop, NULL);
2639 2640
2640 2641 // Verify the stack frames.
2641 2642 frames_do(frame_verify);
2642 2643 }
2643 2644
2644 2645 // CR 6300358 (sub-CR 2137150)
2645 2646 // Most callers of this method assume that it can't return NULL but a
2646 2647 // thread may not have a name whilst it is in the process of attaching to
2647 2648 // the VM - see CR 6412693, and there are places where a JavaThread can be
2648 2649 // seen prior to having it's threadObj set (eg JNI attaching threads and
2649 2650 // if vm exit occurs during initialization). These cases can all be accounted
2650 2651 // for such that this method never returns NULL.
2651 2652 const char* JavaThread::get_thread_name() const {
2652 2653 #ifdef ASSERT
2653 2654 // early safepoints can hit while current thread does not yet have TLS
2654 2655 if (!SafepointSynchronize::is_at_safepoint()) {
2655 2656 Thread *cur = Thread::current();
2656 2657 if (!(cur->is_Java_thread() && cur == this)) {
2657 2658 // Current JavaThreads are allowed to get their own name without
2658 2659 // the Threads_lock.
2659 2660 assert_locked_or_safepoint(Threads_lock);
2660 2661 }
2661 2662 }
2662 2663 #endif // ASSERT
2663 2664 return get_thread_name_string();
2664 2665 }
2665 2666
2666 2667 // Returns a non-NULL representation of this thread's name, or a suitable
2667 2668 // descriptive string if there is no set name
2668 2669 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2669 2670 const char* name_str;
2670 2671 oop thread_obj = threadObj();
2671 2672 if (thread_obj != NULL) {
2672 2673 typeArrayOop name = java_lang_Thread::name(thread_obj);
2673 2674 if (name != NULL) {
2674 2675 if (buf == NULL) {
2675 2676 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2676 2677 }
2677 2678 else {
2678 2679 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2679 2680 }
2680 2681 }
2681 2682 else if (is_attaching()) { // workaround for 6412693 - see 6404306
2682 2683 name_str = "<no-name - thread is attaching>";
2683 2684 }
2684 2685 else {
2685 2686 name_str = Thread::name();
2686 2687 }
2687 2688 }
2688 2689 else {
2689 2690 name_str = Thread::name();
2690 2691 }
2691 2692 assert(name_str != NULL, "unexpected NULL thread name");
2692 2693 return name_str;
2693 2694 }
2694 2695
2695 2696
2696 2697 const char* JavaThread::get_threadgroup_name() const {
2697 2698 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2698 2699 oop thread_obj = threadObj();
2699 2700 if (thread_obj != NULL) {
2700 2701 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2701 2702 if (thread_group != NULL) {
2702 2703 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2703 2704 // ThreadGroup.name can be null
2704 2705 if (name != NULL) {
2705 2706 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2706 2707 return str;
2707 2708 }
2708 2709 }
2709 2710 }
2710 2711 return NULL;
2711 2712 }
2712 2713
2713 2714 const char* JavaThread::get_parent_name() const {
2714 2715 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2715 2716 oop thread_obj = threadObj();
2716 2717 if (thread_obj != NULL) {
2717 2718 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2718 2719 if (thread_group != NULL) {
2719 2720 oop parent = java_lang_ThreadGroup::parent(thread_group);
2720 2721 if (parent != NULL) {
2721 2722 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2722 2723 // ThreadGroup.name can be null
2723 2724 if (name != NULL) {
2724 2725 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2725 2726 return str;
2726 2727 }
2727 2728 }
2728 2729 }
2729 2730 }
2730 2731 return NULL;
2731 2732 }
2732 2733
2733 2734 ThreadPriority JavaThread::java_priority() const {
2734 2735 oop thr_oop = threadObj();
2735 2736 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2736 2737 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2737 2738 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2738 2739 return priority;
2739 2740 }
2740 2741
2741 2742 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2742 2743
2743 2744 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2744 2745 // Link Java Thread object <-> C++ Thread
2745 2746
2746 2747 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2747 2748 // and put it into a new Handle. The Handle "thread_oop" can then
2748 2749 // be used to pass the C++ thread object to other methods.
2749 2750
2750 2751 // Set the Java level thread object (jthread) field of the
2751 2752 // new thread (a JavaThread *) to C++ thread object using the
2752 2753 // "thread_oop" handle.
2753 2754
2754 2755 // Set the thread field (a JavaThread *) of the
2755 2756 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2756 2757
2757 2758 Handle thread_oop(Thread::current(),
2758 2759 JNIHandles::resolve_non_null(jni_thread));
2759 2760 assert(instanceKlass::cast(thread_oop->klass())->is_linked(),
2760 2761 "must be initialized");
2761 2762 set_threadObj(thread_oop());
2762 2763 java_lang_Thread::set_thread(thread_oop(), this);
2763 2764
2764 2765 if (prio == NoPriority) {
2765 2766 prio = java_lang_Thread::priority(thread_oop());
2766 2767 assert(prio != NoPriority, "A valid priority should be present");
2767 2768 }
2768 2769
2769 2770 // Push the Java priority down to the native thread; needs Threads_lock
2770 2771 Thread::set_priority(this, prio);
2771 2772
2772 2773 // Add the new thread to the Threads list and set it in motion.
2773 2774 // We must have threads lock in order to call Threads::add.
2774 2775 // It is crucial that we do not block before the thread is
2775 2776 // added to the Threads list for if a GC happens, then the java_thread oop
2776 2777 // will not be visited by GC.
2777 2778 Threads::add(this);
2778 2779 }
2779 2780
2780 2781 oop JavaThread::current_park_blocker() {
2781 2782 // Support for JSR-166 locks
2782 2783 oop thread_oop = threadObj();
2783 2784 if (thread_oop != NULL &&
2784 2785 JDK_Version::current().supports_thread_park_blocker()) {
2785 2786 return java_lang_Thread::park_blocker(thread_oop);
2786 2787 }
2787 2788 return NULL;
2788 2789 }
2789 2790
2790 2791
2791 2792 void JavaThread::print_stack_on(outputStream* st) {
2792 2793 if (!has_last_Java_frame()) return;
2793 2794 ResourceMark rm;
2794 2795 HandleMark hm;
2795 2796
2796 2797 RegisterMap reg_map(this);
2797 2798 vframe* start_vf = last_java_vframe(®_map);
2798 2799 int count = 0;
2799 2800 for (vframe* f = start_vf; f; f = f->sender() ) {
2800 2801 if (f->is_java_frame()) {
2801 2802 javaVFrame* jvf = javaVFrame::cast(f);
2802 2803 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2803 2804
2804 2805 // Print out lock information
2805 2806 if (JavaMonitorsInStackTrace) {
2806 2807 jvf->print_lock_info_on(st, count);
2807 2808 }
2808 2809 } else {
2809 2810 // Ignore non-Java frames
2810 2811 }
2811 2812
2812 2813 // Bail-out case for too deep stacks
2813 2814 count++;
2814 2815 if (MaxJavaStackTraceDepth == count) return;
2815 2816 }
2816 2817 }
2817 2818
2818 2819
2819 2820 // JVMTI PopFrame support
2820 2821 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2821 2822 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2822 2823 if (in_bytes(size_in_bytes) != 0) {
2823 2824 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes));
2824 2825 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2825 2826 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2826 2827 }
2827 2828 }
2828 2829
2829 2830 void* JavaThread::popframe_preserved_args() {
2830 2831 return _popframe_preserved_args;
2831 2832 }
2832 2833
2833 2834 ByteSize JavaThread::popframe_preserved_args_size() {
2834 2835 return in_ByteSize(_popframe_preserved_args_size);
2835 2836 }
2836 2837
2837 2838 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2838 2839 int sz = in_bytes(popframe_preserved_args_size());
2839 2840 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2840 2841 return in_WordSize(sz / wordSize);
2841 2842 }
2842 2843
2843 2844 void JavaThread::popframe_free_preserved_args() {
2844 2845 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
2845 2846 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
2846 2847 _popframe_preserved_args = NULL;
2847 2848 _popframe_preserved_args_size = 0;
2848 2849 }
2849 2850
2850 2851 #ifndef PRODUCT
2851 2852
2852 2853 void JavaThread::trace_frames() {
2853 2854 tty->print_cr("[Describe stack]");
2854 2855 int frame_no = 1;
2855 2856 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2856 2857 tty->print(" %d. ", frame_no++);
2857 2858 fst.current()->print_value_on(tty,this);
2858 2859 tty->cr();
2859 2860 }
2860 2861 }
2861 2862
2862 2863 class PrintAndVerifyOopClosure: public OopClosure {
2863 2864 protected:
2864 2865 template <class T> inline void do_oop_work(T* p) {
2865 2866 oop obj = oopDesc::load_decode_heap_oop(p);
2866 2867 if (obj == NULL) return;
2867 2868 tty->print(INTPTR_FORMAT ": ", p);
2868 2869 if (obj->is_oop_or_null()) {
2869 2870 if (obj->is_objArray()) {
2870 2871 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj);
2871 2872 } else {
2872 2873 obj->print();
2873 2874 }
2874 2875 } else {
2875 2876 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj);
2876 2877 }
2877 2878 tty->cr();
2878 2879 }
2879 2880 public:
2880 2881 virtual void do_oop(oop* p) { do_oop_work(p); }
2881 2882 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
2882 2883 };
2883 2884
2884 2885
2885 2886 static void oops_print(frame* f, const RegisterMap *map) {
2886 2887 PrintAndVerifyOopClosure print;
2887 2888 f->print_value();
2888 2889 f->oops_do(&print, NULL, (RegisterMap*)map);
2889 2890 }
2890 2891
2891 2892 // Print our all the locations that contain oops and whether they are
2892 2893 // valid or not. This useful when trying to find the oldest frame
2893 2894 // where an oop has gone bad since the frame walk is from youngest to
2894 2895 // oldest.
2895 2896 void JavaThread::trace_oops() {
2896 2897 tty->print_cr("[Trace oops]");
2897 2898 frames_do(oops_print);
2898 2899 }
2899 2900
2900 2901
2901 2902 #ifdef ASSERT
2902 2903 // Print or validate the layout of stack frames
2903 2904 void JavaThread::print_frame_layout(int depth, bool validate_only) {
2904 2905 ResourceMark rm;
2905 2906 PRESERVE_EXCEPTION_MARK;
2906 2907 FrameValues values;
2907 2908 int frame_no = 0;
2908 2909 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
2909 2910 fst.current()->describe(values, ++frame_no);
2910 2911 if (depth == frame_no) break;
2911 2912 }
2912 2913 if (validate_only) {
2913 2914 values.validate();
2914 2915 } else {
2915 2916 tty->print_cr("[Describe stack layout]");
2916 2917 values.print();
2917 2918 }
2918 2919 }
2919 2920 #endif
2920 2921
2921 2922 void JavaThread::trace_stack_from(vframe* start_vf) {
2922 2923 ResourceMark rm;
2923 2924 int vframe_no = 1;
2924 2925 for (vframe* f = start_vf; f; f = f->sender() ) {
2925 2926 if (f->is_java_frame()) {
2926 2927 javaVFrame::cast(f)->print_activation(vframe_no++);
2927 2928 } else {
2928 2929 f->print();
2929 2930 }
2930 2931 if (vframe_no > StackPrintLimit) {
2931 2932 tty->print_cr("...<more frames>...");
2932 2933 return;
2933 2934 }
2934 2935 }
2935 2936 }
2936 2937
2937 2938
2938 2939 void JavaThread::trace_stack() {
2939 2940 if (!has_last_Java_frame()) return;
2940 2941 ResourceMark rm;
2941 2942 HandleMark hm;
2942 2943 RegisterMap reg_map(this);
2943 2944 trace_stack_from(last_java_vframe(®_map));
2944 2945 }
2945 2946
2946 2947
2947 2948 #endif // PRODUCT
2948 2949
2949 2950
2950 2951 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
2951 2952 assert(reg_map != NULL, "a map must be given");
2952 2953 frame f = last_frame();
2953 2954 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
2954 2955 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2955 2956 }
2956 2957 return NULL;
2957 2958 }
2958 2959
2959 2960
2960 2961 klassOop JavaThread::security_get_caller_class(int depth) {
2961 2962 vframeStream vfst(this);
2962 2963 vfst.security_get_caller_frame(depth);
2963 2964 if (!vfst.at_end()) {
2964 2965 return vfst.method()->method_holder();
2965 2966 }
2966 2967 return NULL;
2967 2968 }
2968 2969
2969 2970 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
2970 2971 assert(thread->is_Compiler_thread(), "must be compiler thread");
2971 2972 CompileBroker::compiler_thread_loop();
2972 2973 }
2973 2974
2974 2975 // Create a CompilerThread
2975 2976 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
2976 2977 : JavaThread(&compiler_thread_entry) {
2977 2978 _env = NULL;
2978 2979 _log = NULL;
2979 2980 _task = NULL;
2980 2981 _queue = queue;
2981 2982 _counters = counters;
2982 2983 _buffer_blob = NULL;
2983 2984 _scanned_nmethod = NULL;
2984 2985
2985 2986 #ifndef PRODUCT
2986 2987 _ideal_graph_printer = NULL;
2987 2988 #endif
2988 2989 }
2989 2990
2990 2991 void CompilerThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2991 2992 JavaThread::oops_do(f, cf);
2992 2993 if (_scanned_nmethod != NULL && cf != NULL) {
2993 2994 // Safepoints can occur when the sweeper is scanning an nmethod so
2994 2995 // process it here to make sure it isn't unloaded in the middle of
2995 2996 // a scan.
2996 2997 cf->do_code_blob(_scanned_nmethod);
2997 2998 }
2998 2999 }
2999 3000
3000 3001 // ======= Threads ========
3001 3002
3002 3003 // The Threads class links together all active threads, and provides
3003 3004 // operations over all threads. It is protected by its own Mutex
3004 3005 // lock, which is also used in other contexts to protect thread
3005 3006 // operations from having the thread being operated on from exiting
3006 3007 // and going away unexpectedly (e.g., safepoint synchronization)
3007 3008
3008 3009 JavaThread* Threads::_thread_list = NULL;
3009 3010 int Threads::_number_of_threads = 0;
3010 3011 int Threads::_number_of_non_daemon_threads = 0;
3011 3012 int Threads::_return_code = 0;
3012 3013 size_t JavaThread::_stack_size_at_create = 0;
3013 3014
3014 3015 // All JavaThreads
3015 3016 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
3016 3017
3017 3018 void os_stream();
3018 3019
3019 3020 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
3020 3021 void Threads::threads_do(ThreadClosure* tc) {
3021 3022 assert_locked_or_safepoint(Threads_lock);
3022 3023 // ALL_JAVA_THREADS iterates through all JavaThreads
3023 3024 ALL_JAVA_THREADS(p) {
3024 3025 tc->do_thread(p);
3025 3026 }
3026 3027 // Someday we could have a table or list of all non-JavaThreads.
3027 3028 // For now, just manually iterate through them.
3028 3029 tc->do_thread(VMThread::vm_thread());
3029 3030 Universe::heap()->gc_threads_do(tc);
3030 3031 WatcherThread *wt = WatcherThread::watcher_thread();
3031 3032 // Strictly speaking, the following NULL check isn't sufficient to make sure
3032 3033 // the data for WatcherThread is still valid upon being examined. However,
3033 3034 // considering that WatchThread terminates when the VM is on the way to
3034 3035 // exit at safepoint, the chance of the above is extremely small. The right
3035 3036 // way to prevent termination of WatcherThread would be to acquire
3036 3037 // Terminator_lock, but we can't do that without violating the lock rank
3037 3038 // checking in some cases.
3038 3039 if (wt != NULL)
3039 3040 tc->do_thread(wt);
3040 3041
3041 3042 // If CompilerThreads ever become non-JavaThreads, add them here
3042 3043 }
3043 3044
3044 3045 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
3045 3046
3046 3047 extern void JDK_Version_init();
3047 3048
3048 3049 // Check version
3049 3050 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
3050 3051
3051 3052 // Initialize the output stream module
3052 3053 ostream_init();
3053 3054
3054 3055 // Process java launcher properties.
3055 3056 Arguments::process_sun_java_launcher_properties(args);
3056 3057
3057 3058 // Initialize the os module before using TLS
3058 3059 os::init();
3059 3060
3060 3061 // Initialize system properties.
3061 3062 Arguments::init_system_properties();
3062 3063
3063 3064 // So that JDK version can be used as a discrimintor when parsing arguments
3064 3065 JDK_Version_init();
3065 3066
3066 3067 // Update/Initialize System properties after JDK version number is known
3067 3068 Arguments::init_version_specific_system_properties();
3068 3069
3069 3070 // Parse arguments
3070 3071 jint parse_result = Arguments::parse(args);
3071 3072 if (parse_result != JNI_OK) return parse_result;
3072 3073
3073 3074 if (PauseAtStartup) {
3074 3075 os::pause();
3075 3076 }
3076 3077
3077 3078 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3078 3079
3079 3080 // Record VM creation timing statistics
3080 3081 TraceVmCreationTime create_vm_timer;
3081 3082 create_vm_timer.start();
3082 3083
3083 3084 // Timing (must come after argument parsing)
3084 3085 TraceTime timer("Create VM", TraceStartupTime);
3085 3086
3086 3087 // Initialize the os module after parsing the args
3087 3088 jint os_init_2_result = os::init_2();
3088 3089 if (os_init_2_result != JNI_OK) return os_init_2_result;
3089 3090
3090 3091 // Initialize output stream logging
3091 3092 ostream_init_log();
3092 3093
3093 3094 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3094 3095 // Must be before create_vm_init_agents()
3095 3096 if (Arguments::init_libraries_at_startup()) {
3096 3097 convert_vm_init_libraries_to_agents();
3097 3098 }
3098 3099
3099 3100 // Launch -agentlib/-agentpath and converted -Xrun agents
3100 3101 if (Arguments::init_agents_at_startup()) {
3101 3102 create_vm_init_agents();
3102 3103 }
3103 3104
3104 3105 // Initialize Threads state
3105 3106 _thread_list = NULL;
3106 3107 _number_of_threads = 0;
3107 3108 _number_of_non_daemon_threads = 0;
3108 3109
3109 3110 // Initialize TLS
3110 3111 ThreadLocalStorage::init();
3111 3112
3112 3113 // Initialize global data structures and create system classes in heap
3113 3114 vm_init_globals();
3114 3115
3115 3116 // Attach the main thread to this os thread
3116 3117 JavaThread* main_thread = new JavaThread();
3117 3118 main_thread->set_thread_state(_thread_in_vm);
3118 3119 // must do this before set_active_handles and initialize_thread_local_storage
3119 3120 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3120 3121 // change the stack size recorded here to one based on the java thread
3121 3122 // stacksize. This adjusted size is what is used to figure the placement
3122 3123 // of the guard pages.
3123 3124 main_thread->record_stack_base_and_size();
3124 3125 main_thread->initialize_thread_local_storage();
3125 3126
3126 3127 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3127 3128
3128 3129 if (!main_thread->set_as_starting_thread()) {
3129 3130 vm_shutdown_during_initialization(
3130 3131 "Failed necessary internal allocation. Out of swap space");
3131 3132 delete main_thread;
3132 3133 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3133 3134 return JNI_ENOMEM;
3134 3135 }
3135 3136
3136 3137 // Enable guard page *after* os::create_main_thread(), otherwise it would
3137 3138 // crash Linux VM, see notes in os_linux.cpp.
3138 3139 main_thread->create_stack_guard_pages();
3139 3140
3140 3141 // Initialize Java-Level synchronization subsystem
3141 3142 ObjectMonitor::Initialize() ;
3142 3143
3143 3144 // Initialize global modules
3144 3145 jint status = init_globals();
3145 3146 if (status != JNI_OK) {
3146 3147 delete main_thread;
3147 3148 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3148 3149 return status;
3149 3150 }
3150 3151
3151 3152 // Should be done after the heap is fully created
3152 3153 main_thread->cache_global_variables();
3153 3154
3154 3155 HandleMark hm;
3155 3156
3156 3157 { MutexLocker mu(Threads_lock);
3157 3158 Threads::add(main_thread);
3158 3159 }
3159 3160
3160 3161 // Any JVMTI raw monitors entered in onload will transition into
3161 3162 // real raw monitor. VM is setup enough here for raw monitor enter.
3162 3163 JvmtiExport::transition_pending_onload_raw_monitors();
3163 3164
3164 3165 if (VerifyBeforeGC &&
3165 3166 Universe::heap()->total_collections() >= VerifyGCStartAt) {
3166 3167 Universe::heap()->prepare_for_verify();
3167 3168 Universe::verify(); // make sure we're starting with a clean slate
3168 3169 }
3169 3170
3170 3171 // Create the VMThread
3171 3172 { TraceTime timer("Start VMThread", TraceStartupTime);
3172 3173 VMThread::create();
3173 3174 Thread* vmthread = VMThread::vm_thread();
3174 3175
3175 3176 if (!os::create_thread(vmthread, os::vm_thread))
3176 3177 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3177 3178
3178 3179 // Wait for the VM thread to become ready, and VMThread::run to initialize
3179 3180 // Monitors can have spurious returns, must always check another state flag
3180 3181 {
3181 3182 MutexLocker ml(Notify_lock);
3182 3183 os::start_thread(vmthread);
3183 3184 while (vmthread->active_handles() == NULL) {
3184 3185 Notify_lock->wait();
3185 3186 }
3186 3187 }
3187 3188 }
3188 3189
3189 3190 assert (Universe::is_fully_initialized(), "not initialized");
3190 3191 EXCEPTION_MARK;
3191 3192
3192 3193 // At this point, the Universe is initialized, but we have not executed
3193 3194 // any byte code. Now is a good time (the only time) to dump out the
3194 3195 // internal state of the JVM for sharing.
3195 3196
3196 3197 if (DumpSharedSpaces) {
3197 3198 Universe::heap()->preload_and_dump(CHECK_0);
3198 3199 ShouldNotReachHere();
3199 3200 }
3200 3201
3201 3202 // Always call even when there are not JVMTI environments yet, since environments
3202 3203 // may be attached late and JVMTI must track phases of VM execution
3203 3204 JvmtiExport::enter_start_phase();
3204 3205
3205 3206 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3206 3207 JvmtiExport::post_vm_start();
3207 3208
3208 3209 {
3209 3210 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3210 3211
3211 3212 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3212 3213 create_vm_init_libraries();
3213 3214 }
3214 3215
3215 3216 if (InitializeJavaLangString) {
3216 3217 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3217 3218 } else {
3218 3219 warning("java.lang.String not initialized");
3219 3220 }
3220 3221
3221 3222 if (AggressiveOpts) {
3222 3223 {
3223 3224 // Forcibly initialize java/util/HashMap and mutate the private
3224 3225 // static final "frontCacheEnabled" field before we start creating instances
3225 3226 #ifdef ASSERT
3226 3227 klassOop tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3227 3228 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
3228 3229 #endif
3229 3230 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3230 3231 KlassHandle k = KlassHandle(THREAD, k_o);
3231 3232 guarantee(k.not_null(), "Must find java/util/HashMap");
3232 3233 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3233 3234 ik->initialize(CHECK_0);
3234 3235 fieldDescriptor fd;
3235 3236 // Possible we might not find this field; if so, don't break
3236 3237 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3237 3238 k()->java_mirror()->bool_field_put(fd.offset(), true);
3238 3239 }
3239 3240 }
3240 3241
3241 3242 if (UseStringCache) {
3242 3243 // Forcibly initialize java/lang/StringValue and mutate the private
3243 3244 // static final "stringCacheEnabled" field before we start creating instances
3244 3245 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
3245 3246 // Possible that StringValue isn't present: if so, silently don't break
3246 3247 if (k_o != NULL) {
3247 3248 KlassHandle k = KlassHandle(THREAD, k_o);
3248 3249 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3249 3250 ik->initialize(CHECK_0);
3250 3251 fieldDescriptor fd;
3251 3252 // Possible we might not find this field: if so, silently don't break
3252 3253 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3253 3254 k()->java_mirror()->bool_field_put(fd.offset(), true);
3254 3255 }
3255 3256 }
3256 3257 }
3257 3258 }
3258 3259
3259 3260 // Initialize java_lang.System (needed before creating the thread)
3260 3261 if (InitializeJavaLangSystem) {
3261 3262 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3262 3263 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3263 3264 Handle thread_group = create_initial_thread_group(CHECK_0);
3264 3265 Universe::set_main_thread_group(thread_group());
3265 3266 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3266 3267 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3267 3268 main_thread->set_threadObj(thread_object);
3268 3269 // Set thread status to running since main thread has
3269 3270 // been started and running.
3270 3271 java_lang_Thread::set_thread_status(thread_object,
3271 3272 java_lang_Thread::RUNNABLE);
3272 3273
3273 3274 // The VM preresolve methods to these classes. Make sure that get initialized
3274 3275 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3275 3276 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3276 3277 // The VM creates & returns objects of this class. Make sure it's initialized.
3277 3278 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3278 3279 call_initializeSystemClass(CHECK_0);
3279 3280 } else {
3280 3281 warning("java.lang.System not initialized");
3281 3282 }
3282 3283
3283 3284 // an instance of OutOfMemory exception has been allocated earlier
3284 3285 if (InitializeJavaLangExceptionsErrors) {
3285 3286 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3286 3287 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3287 3288 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3288 3289 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3289 3290 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
3290 3291 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3291 3292 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3292 3293 } else {
3293 3294 warning("java.lang.OutOfMemoryError has not been initialized");
3294 3295 warning("java.lang.NullPointerException has not been initialized");
3295 3296 warning("java.lang.ClassCastException has not been initialized");
3296 3297 warning("java.lang.ArrayStoreException has not been initialized");
3297 3298 warning("java.lang.ArithmeticException has not been initialized");
3298 3299 warning("java.lang.StackOverflowError has not been initialized");
3299 3300 }
3300 3301 }
3301 3302
3302 3303 // See : bugid 4211085.
3303 3304 // Background : the static initializer of java.lang.Compiler tries to read
3304 3305 // property"java.compiler" and read & write property "java.vm.info".
3305 3306 // When a security manager is installed through the command line
3306 3307 // option "-Djava.security.manager", the above properties are not
3307 3308 // readable and the static initializer for java.lang.Compiler fails
3308 3309 // resulting in a NoClassDefFoundError. This can happen in any
3309 3310 // user code which calls methods in java.lang.Compiler.
3310 3311 // Hack : the hack is to pre-load and initialize this class, so that only
3311 3312 // system domains are on the stack when the properties are read.
3312 3313 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3313 3314 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3314 3315 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3315 3316 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3316 3317 // Once that is done, we should remove this hack.
3317 3318 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3318 3319
3319 3320 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3320 3321 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3321 3322 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3322 3323 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3323 3324 // This should also be taken out as soon as 4211383 gets fixed.
3324 3325 reset_vm_info_property(CHECK_0);
3325 3326
3326 3327 quicken_jni_functions();
3327 3328
3328 3329 // Set flag that basic initialization has completed. Used by exceptions and various
3329 3330 // debug stuff, that does not work until all basic classes have been initialized.
3330 3331 set_init_completed();
3331 3332
3332 3333 HS_DTRACE_PROBE(hotspot, vm__init__end);
3333 3334
3334 3335 // record VM initialization completion time
3335 3336 Management::record_vm_init_completed();
3336 3337
3337 3338 // Compute system loader. Note that this has to occur after set_init_completed, since
3338 3339 // valid exceptions may be thrown in the process.
3339 3340 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3340 3341 // set_init_completed has just been called, causing exceptions not to be shortcut
3341 3342 // anymore. We call vm_exit_during_initialization directly instead.
3342 3343 SystemDictionary::compute_java_system_loader(THREAD);
3343 3344 if (HAS_PENDING_EXCEPTION) {
3344 3345 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3345 3346 }
3346 3347
3347 3348 #ifndef SERIALGC
3348 3349 // Support for ConcurrentMarkSweep. This should be cleaned up
3349 3350 // and better encapsulated. The ugly nested if test would go away
3350 3351 // once things are properly refactored. XXX YSR
3351 3352 if (UseConcMarkSweepGC || UseG1GC) {
3352 3353 if (UseConcMarkSweepGC) {
3353 3354 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3354 3355 } else {
3355 3356 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3356 3357 }
3357 3358 if (HAS_PENDING_EXCEPTION) {
3358 3359 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3359 3360 }
3360 3361 }
3361 3362 #endif // SERIALGC
3362 3363
3363 3364 // Always call even when there are not JVMTI environments yet, since environments
3364 3365 // may be attached late and JVMTI must track phases of VM execution
3365 3366 JvmtiExport::enter_live_phase();
3366 3367
3367 3368 // Signal Dispatcher needs to be started before VMInit event is posted
3368 3369 os::signal_init();
3369 3370
3370 3371 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3371 3372 if (!DisableAttachMechanism) {
3372 3373 if (StartAttachListener || AttachListener::init_at_startup()) {
3373 3374 AttachListener::init();
3374 3375 }
3375 3376 }
3376 3377
3377 3378 // Launch -Xrun agents
3378 3379 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3379 3380 // back-end can launch with -Xdebug -Xrunjdwp.
3380 3381 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3381 3382 create_vm_init_libraries();
3382 3383 }
3383 3384
3384 3385 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3385 3386 JvmtiExport::post_vm_initialized();
3386 3387
3387 3388 if (CleanChunkPoolAsync) {
3388 3389 Chunk::start_chunk_pool_cleaner_task();
3389 3390 }
3390 3391
3391 3392 // initialize compiler(s)
3392 3393 CompileBroker::compilation_init();
3393 3394
3394 3395 Management::initialize(THREAD);
3395 3396 if (HAS_PENDING_EXCEPTION) {
3396 3397 // management agent fails to start possibly due to
3397 3398 // configuration problem and is responsible for printing
3398 3399 // stack trace if appropriate. Simply exit VM.
3399 3400 vm_exit(1);
3400 3401 }
3401 3402
3402 3403 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3403 3404 if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3404 3405 if (MemProfiling) MemProfiler::engage();
3405 3406 StatSampler::engage();
3406 3407 if (CheckJNICalls) JniPeriodicChecker::engage();
3407 3408
3408 3409 BiasedLocking::init();
3409 3410
3410 3411 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3411 3412 call_postVMInitHook(THREAD);
3412 3413 // The Java side of PostVMInitHook.run must deal with all
3413 3414 // exceptions and provide means of diagnosis.
3414 3415 if (HAS_PENDING_EXCEPTION) {
3415 3416 CLEAR_PENDING_EXCEPTION;
3416 3417 }
3417 3418 }
3418 3419
3419 3420 // Start up the WatcherThread if there are any periodic tasks
3420 3421 // NOTE: All PeriodicTasks should be registered by now. If they
3421 3422 // aren't, late joiners might appear to start slowly (we might
3422 3423 // take a while to process their first tick).
3423 3424 if (PeriodicTask::num_tasks() > 0) {
3424 3425 WatcherThread::start();
3425 3426 }
3426 3427
3427 3428 // Give os specific code one last chance to start
3428 3429 os::init_3();
3429 3430
3430 3431 create_vm_timer.end();
3431 3432 return JNI_OK;
3432 3433 }
3433 3434
3434 3435 // type for the Agent_OnLoad and JVM_OnLoad entry points
3435 3436 extern "C" {
3436 3437 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3437 3438 }
3438 3439 // Find a command line agent library and return its entry point for
3439 3440 // -agentlib: -agentpath: -Xrun
3440 3441 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3441 3442 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3442 3443 OnLoadEntry_t on_load_entry = NULL;
3443 3444 void *library = agent->os_lib(); // check if we have looked it up before
3444 3445
3445 3446 if (library == NULL) {
3446 3447 char buffer[JVM_MAXPATHLEN];
3447 3448 char ebuf[1024];
3448 3449 const char *name = agent->name();
3449 3450 const char *msg = "Could not find agent library ";
3450 3451
3451 3452 if (agent->is_absolute_path()) {
3452 3453 library = os::dll_load(name, ebuf, sizeof ebuf);
3453 3454 if (library == NULL) {
3454 3455 const char *sub_msg = " in absolute path, with error: ";
3455 3456 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3456 3457 char *buf = NEW_C_HEAP_ARRAY(char, len);
3457 3458 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3458 3459 // If we can't find the agent, exit.
3459 3460 vm_exit_during_initialization(buf, NULL);
3460 3461 FREE_C_HEAP_ARRAY(char, buf);
3461 3462 }
3462 3463 } else {
3463 3464 // Try to load the agent from the standard dll directory
3464 3465 os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name);
3465 3466 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3466 3467 #ifdef KERNEL
3467 3468 // Download instrument dll
3468 3469 if (library == NULL && strcmp(name, "instrument") == 0) {
3469 3470 char *props = Arguments::get_kernel_properties();
3470 3471 char *home = Arguments::get_java_home();
3471 3472 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false"
3472 3473 " sun.jkernel.DownloadManager -download client_jvm";
3473 3474 size_t length = strlen(props) + strlen(home) + strlen(fmt) + 1;
3474 3475 char *cmd = NEW_C_HEAP_ARRAY(char, length);
3475 3476 jio_snprintf(cmd, length, fmt, home, props);
3476 3477 int status = os::fork_and_exec(cmd);
3477 3478 FreeHeap(props);
3478 3479 if (status == -1) {
3479 3480 warning(cmd);
3480 3481 vm_exit_during_initialization("fork_and_exec failed: %s",
3481 3482 strerror(errno));
3482 3483 }
3483 3484 FREE_C_HEAP_ARRAY(char, cmd);
3484 3485 // when this comes back the instrument.dll should be where it belongs.
3485 3486 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3486 3487 }
3487 3488 #endif // KERNEL
3488 3489 if (library == NULL) { // Try the local directory
3489 3490 char ns[1] = {0};
3490 3491 os::dll_build_name(buffer, sizeof(buffer), ns, name);
3491 3492 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3492 3493 if (library == NULL) {
3493 3494 const char *sub_msg = " on the library path, with error: ";
3494 3495 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3495 3496 char *buf = NEW_C_HEAP_ARRAY(char, len);
3496 3497 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3497 3498 // If we can't find the agent, exit.
3498 3499 vm_exit_during_initialization(buf, NULL);
3499 3500 FREE_C_HEAP_ARRAY(char, buf);
3500 3501 }
3501 3502 }
3502 3503 }
3503 3504 agent->set_os_lib(library);
3504 3505 }
3505 3506
3506 3507 // Find the OnLoad function.
3507 3508 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3508 3509 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index]));
3509 3510 if (on_load_entry != NULL) break;
3510 3511 }
3511 3512 return on_load_entry;
3512 3513 }
3513 3514
3514 3515 // Find the JVM_OnLoad entry point
3515 3516 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3516 3517 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3517 3518 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3518 3519 }
3519 3520
3520 3521 // Find the Agent_OnLoad entry point
3521 3522 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3522 3523 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3523 3524 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3524 3525 }
3525 3526
3526 3527 // For backwards compatibility with -Xrun
3527 3528 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3528 3529 // treated like -agentpath:
3529 3530 // Must be called before agent libraries are created
3530 3531 void Threads::convert_vm_init_libraries_to_agents() {
3531 3532 AgentLibrary* agent;
3532 3533 AgentLibrary* next;
3533 3534
3534 3535 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3535 3536 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3536 3537 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3537 3538
3538 3539 // If there is an JVM_OnLoad function it will get called later,
3539 3540 // otherwise see if there is an Agent_OnLoad
3540 3541 if (on_load_entry == NULL) {
3541 3542 on_load_entry = lookup_agent_on_load(agent);
3542 3543 if (on_load_entry != NULL) {
3543 3544 // switch it to the agent list -- so that Agent_OnLoad will be called,
3544 3545 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3545 3546 Arguments::convert_library_to_agent(agent);
3546 3547 } else {
3547 3548 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3548 3549 }
3549 3550 }
3550 3551 }
3551 3552 }
3552 3553
3553 3554 // Create agents for -agentlib: -agentpath: and converted -Xrun
3554 3555 // Invokes Agent_OnLoad
3555 3556 // Called very early -- before JavaThreads exist
3556 3557 void Threads::create_vm_init_agents() {
3557 3558 extern struct JavaVM_ main_vm;
3558 3559 AgentLibrary* agent;
3559 3560
3560 3561 JvmtiExport::enter_onload_phase();
3561 3562 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3562 3563 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3563 3564
3564 3565 if (on_load_entry != NULL) {
3565 3566 // Invoke the Agent_OnLoad function
3566 3567 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3567 3568 if (err != JNI_OK) {
3568 3569 vm_exit_during_initialization("agent library failed to init", agent->name());
3569 3570 }
3570 3571 } else {
3571 3572 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3572 3573 }
3573 3574 }
3574 3575 JvmtiExport::enter_primordial_phase();
3575 3576 }
3576 3577
3577 3578 extern "C" {
3578 3579 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3579 3580 }
3580 3581
3581 3582 void Threads::shutdown_vm_agents() {
3582 3583 // Send any Agent_OnUnload notifications
3583 3584 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3584 3585 extern struct JavaVM_ main_vm;
3585 3586 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3586 3587
3587 3588 // Find the Agent_OnUnload function.
3588 3589 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3589 3590 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3590 3591 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3591 3592
3592 3593 // Invoke the Agent_OnUnload function
3593 3594 if (unload_entry != NULL) {
3594 3595 JavaThread* thread = JavaThread::current();
3595 3596 ThreadToNativeFromVM ttn(thread);
3596 3597 HandleMark hm(thread);
3597 3598 (*unload_entry)(&main_vm);
3598 3599 break;
3599 3600 }
3600 3601 }
3601 3602 }
3602 3603 }
3603 3604
3604 3605 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3605 3606 // Invokes JVM_OnLoad
3606 3607 void Threads::create_vm_init_libraries() {
3607 3608 extern struct JavaVM_ main_vm;
3608 3609 AgentLibrary* agent;
3609 3610
3610 3611 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3611 3612 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3612 3613
3613 3614 if (on_load_entry != NULL) {
3614 3615 // Invoke the JVM_OnLoad function
3615 3616 JavaThread* thread = JavaThread::current();
3616 3617 ThreadToNativeFromVM ttn(thread);
3617 3618 HandleMark hm(thread);
3618 3619 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3619 3620 if (err != JNI_OK) {
3620 3621 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3621 3622 }
3622 3623 } else {
3623 3624 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3624 3625 }
3625 3626 }
3626 3627 }
3627 3628
3628 3629 // Last thread running calls java.lang.Shutdown.shutdown()
3629 3630 void JavaThread::invoke_shutdown_hooks() {
3630 3631 HandleMark hm(this);
3631 3632
3632 3633 // We could get here with a pending exception, if so clear it now.
3633 3634 if (this->has_pending_exception()) {
3634 3635 this->clear_pending_exception();
3635 3636 }
3636 3637
3637 3638 EXCEPTION_MARK;
3638 3639 klassOop k =
3639 3640 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3640 3641 THREAD);
3641 3642 if (k != NULL) {
3642 3643 // SystemDictionary::resolve_or_null will return null if there was
3643 3644 // an exception. If we cannot load the Shutdown class, just don't
3644 3645 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3645 3646 // and finalizers (if runFinalizersOnExit is set) won't be run.
3646 3647 // Note that if a shutdown hook was registered or runFinalizersOnExit
3647 3648 // was called, the Shutdown class would have already been loaded
3648 3649 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3649 3650 instanceKlassHandle shutdown_klass (THREAD, k);
3650 3651 JavaValue result(T_VOID);
3651 3652 JavaCalls::call_static(&result,
3652 3653 shutdown_klass,
3653 3654 vmSymbols::shutdown_method_name(),
3654 3655 vmSymbols::void_method_signature(),
3655 3656 THREAD);
3656 3657 }
3657 3658 CLEAR_PENDING_EXCEPTION;
3658 3659 }
3659 3660
3660 3661 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3661 3662 // the program falls off the end of main(). Another VM exit path is through
3662 3663 // vm_exit() when the program calls System.exit() to return a value or when
3663 3664 // there is a serious error in VM. The two shutdown paths are not exactly
3664 3665 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3665 3666 // and VM_Exit op at VM level.
3666 3667 //
3667 3668 // Shutdown sequence:
3668 3669 // + Wait until we are the last non-daemon thread to execute
3669 3670 // <-- every thing is still working at this moment -->
3670 3671 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3671 3672 // shutdown hooks, run finalizers if finalization-on-exit
3672 3673 // + Call before_exit(), prepare for VM exit
3673 3674 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3674 3675 // currently the only user of this mechanism is File.deleteOnExit())
3675 3676 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3676 3677 // post thread end and vm death events to JVMTI,
3677 3678 // stop signal thread
3678 3679 // + Call JavaThread::exit(), it will:
3679 3680 // > release JNI handle blocks, remove stack guard pages
3680 3681 // > remove this thread from Threads list
3681 3682 // <-- no more Java code from this thread after this point -->
3682 3683 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3683 3684 // the compiler threads at safepoint
3684 3685 // <-- do not use anything that could get blocked by Safepoint -->
3685 3686 // + Disable tracing at JNI/JVM barriers
3686 3687 // + Set _vm_exited flag for threads that are still running native code
3687 3688 // + Delete this thread
3688 3689 // + Call exit_globals()
3689 3690 // > deletes tty
3690 3691 // > deletes PerfMemory resources
3691 3692 // + Return to caller
3692 3693
3693 3694 bool Threads::destroy_vm() {
3694 3695 JavaThread* thread = JavaThread::current();
3695 3696
3696 3697 // Wait until we are the last non-daemon thread to execute
3697 3698 { MutexLocker nu(Threads_lock);
3698 3699 while (Threads::number_of_non_daemon_threads() > 1 )
3699 3700 // This wait should make safepoint checks, wait without a timeout,
3700 3701 // and wait as a suspend-equivalent condition.
3701 3702 //
3702 3703 // Note: If the FlatProfiler is running and this thread is waiting
3703 3704 // for another non-daemon thread to finish, then the FlatProfiler
3704 3705 // is waiting for the external suspend request on this thread to
3705 3706 // complete. wait_for_ext_suspend_completion() will eventually
3706 3707 // timeout, but that takes time. Making this wait a suspend-
3707 3708 // equivalent condition solves that timeout problem.
3708 3709 //
3709 3710 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3710 3711 Mutex::_as_suspend_equivalent_flag);
3711 3712 }
3712 3713
3713 3714 // Hang forever on exit if we are reporting an error.
3714 3715 if (ShowMessageBoxOnError && is_error_reported()) {
3715 3716 os::infinite_sleep();
3716 3717 }
3717 3718 os::wait_for_keypress_at_exit();
3718 3719
3719 3720 if (JDK_Version::is_jdk12x_version()) {
3720 3721 // We are the last thread running, so check if finalizers should be run.
3721 3722 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3722 3723 HandleMark rm(thread);
3723 3724 Universe::run_finalizers_on_exit();
3724 3725 } else {
3725 3726 // run Java level shutdown hooks
3726 3727 thread->invoke_shutdown_hooks();
3727 3728 }
3728 3729
3729 3730 before_exit(thread);
3730 3731
3731 3732 thread->exit(true);
3732 3733
3733 3734 // Stop VM thread.
3734 3735 {
3735 3736 // 4945125 The vm thread comes to a safepoint during exit.
3736 3737 // GC vm_operations can get caught at the safepoint, and the
3737 3738 // heap is unparseable if they are caught. Grab the Heap_lock
3738 3739 // to prevent this. The GC vm_operations will not be able to
3739 3740 // queue until after the vm thread is dead.
3740 3741 // After this point, we'll never emerge out of the safepoint before
3741 3742 // the VM exits, so concurrent GC threads do not need to be explicitly
3742 3743 // stopped; they remain inactive until the process exits.
3743 3744 // Note: some concurrent G1 threads may be running during a safepoint,
3744 3745 // but these will not be accessing the heap, just some G1-specific side
3745 3746 // data structures that are not accessed by any other threads but them
3746 3747 // after this point in a terminal safepoint.
3747 3748
3748 3749 MutexLocker ml(Heap_lock);
3749 3750
3750 3751 VMThread::wait_for_vm_thread_exit();
3751 3752 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3752 3753 VMThread::destroy();
3753 3754 }
3754 3755
3755 3756 // clean up ideal graph printers
3756 3757 #if defined(COMPILER2) && !defined(PRODUCT)
3757 3758 IdealGraphPrinter::clean_up();
3758 3759 #endif
3759 3760
3760 3761 // Now, all Java threads are gone except daemon threads. Daemon threads
3761 3762 // running Java code or in VM are stopped by the Safepoint. However,
3762 3763 // daemon threads executing native code are still running. But they
3763 3764 // will be stopped at native=>Java/VM barriers. Note that we can't
3764 3765 // simply kill or suspend them, as it is inherently deadlock-prone.
3765 3766
3766 3767 #ifndef PRODUCT
3767 3768 // disable function tracing at JNI/JVM barriers
3768 3769 TraceJNICalls = false;
3769 3770 TraceJVMCalls = false;
3770 3771 TraceRuntimeCalls = false;
3771 3772 #endif
3772 3773
3773 3774 VM_Exit::set_vm_exited();
3774 3775
3775 3776 notify_vm_shutdown();
3776 3777
3777 3778 delete thread;
3778 3779
3779 3780 // exit_globals() will delete tty
3780 3781 exit_globals();
3781 3782
3782 3783 return true;
3783 3784 }
3784 3785
3785 3786
3786 3787 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3787 3788 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3788 3789 return is_supported_jni_version(version);
3789 3790 }
3790 3791
3791 3792
3792 3793 jboolean Threads::is_supported_jni_version(jint version) {
3793 3794 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3794 3795 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3795 3796 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3796 3797 return JNI_FALSE;
3797 3798 }
3798 3799
3799 3800
3800 3801 void Threads::add(JavaThread* p, bool force_daemon) {
3801 3802 // The threads lock must be owned at this point
3802 3803 assert_locked_or_safepoint(Threads_lock);
3803 3804
3804 3805 // See the comment for this method in thread.hpp for its purpose and
3805 3806 // why it is called here.
3806 3807 p->initialize_queues();
3807 3808 p->set_next(_thread_list);
3808 3809 _thread_list = p;
3809 3810 _number_of_threads++;
3810 3811 oop threadObj = p->threadObj();
3811 3812 bool daemon = true;
3812 3813 // Bootstrapping problem: threadObj can be null for initial
3813 3814 // JavaThread (or for threads attached via JNI)
3814 3815 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3815 3816 _number_of_non_daemon_threads++;
3816 3817 daemon = false;
3817 3818 }
3818 3819
3819 3820 ThreadService::add_thread(p, daemon);
3820 3821
3821 3822 // Possible GC point.
3822 3823 Events::log("Thread added: " INTPTR_FORMAT, p);
3823 3824 }
3824 3825
3825 3826 void Threads::remove(JavaThread* p) {
3826 3827 // Extra scope needed for Thread_lock, so we can check
3827 3828 // that we do not remove thread without safepoint code notice
3828 3829 { MutexLocker ml(Threads_lock);
3829 3830
3830 3831 assert(includes(p), "p must be present");
3831 3832
3832 3833 JavaThread* current = _thread_list;
3833 3834 JavaThread* prev = NULL;
3834 3835
3835 3836 while (current != p) {
3836 3837 prev = current;
3837 3838 current = current->next();
3838 3839 }
3839 3840
3840 3841 if (prev) {
3841 3842 prev->set_next(current->next());
3842 3843 } else {
3843 3844 _thread_list = p->next();
3844 3845 }
3845 3846 _number_of_threads--;
3846 3847 oop threadObj = p->threadObj();
3847 3848 bool daemon = true;
3848 3849 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
3849 3850 _number_of_non_daemon_threads--;
3850 3851 daemon = false;
3851 3852
3852 3853 // Only one thread left, do a notify on the Threads_lock so a thread waiting
3853 3854 // on destroy_vm will wake up.
3854 3855 if (number_of_non_daemon_threads() == 1)
3855 3856 Threads_lock->notify_all();
3856 3857 }
3857 3858 ThreadService::remove_thread(p, daemon);
3858 3859
3859 3860 // Make sure that safepoint code disregard this thread. This is needed since
3860 3861 // the thread might mess around with locks after this point. This can cause it
3861 3862 // to do callbacks into the safepoint code. However, the safepoint code is not aware
3862 3863 // of this thread since it is removed from the queue.
3863 3864 p->set_terminated_value();
3864 3865 } // unlock Threads_lock
3865 3866
3866 3867 // Since Events::log uses a lock, we grab it outside the Threads_lock
3867 3868 Events::log("Thread exited: " INTPTR_FORMAT, p);
3868 3869 }
3869 3870
3870 3871 // Threads_lock must be held when this is called (or must be called during a safepoint)
3871 3872 bool Threads::includes(JavaThread* p) {
3872 3873 assert(Threads_lock->is_locked(), "sanity check");
3873 3874 ALL_JAVA_THREADS(q) {
3874 3875 if (q == p ) {
3875 3876 return true;
3876 3877 }
3877 3878 }
3878 3879 return false;
3879 3880 }
3880 3881
3881 3882 // Operations on the Threads list for GC. These are not explicitly locked,
3882 3883 // but the garbage collector must provide a safe context for them to run.
3883 3884 // In particular, these things should never be called when the Threads_lock
3884 3885 // is held by some other thread. (Note: the Safepoint abstraction also
3885 3886 // uses the Threads_lock to gurantee this property. It also makes sure that
3886 3887 // all threads gets blocked when exiting or starting).
3887 3888
3888 3889 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3889 3890 ALL_JAVA_THREADS(p) {
3890 3891 p->oops_do(f, cf);
3891 3892 }
3892 3893 VMThread::vm_thread()->oops_do(f, cf);
3893 3894 }
3894 3895
3895 3896 void Threads::possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf) {
3896 3897 // Introduce a mechanism allowing parallel threads to claim threads as
3897 3898 // root groups. Overhead should be small enough to use all the time,
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3898 3899 // even in sequential code.
3899 3900 SharedHeap* sh = SharedHeap::heap();
3900 3901 bool is_par = (sh->n_par_threads() > 0);
3901 3902 int cp = SharedHeap::heap()->strong_roots_parity();
3902 3903 ALL_JAVA_THREADS(p) {
3903 3904 if (p->claim_oops_do(is_par, cp)) {
3904 3905 p->oops_do(f, cf);
3905 3906 }
3906 3907 }
3907 3908 VMThread* vmt = VMThread::vm_thread();
3908 - if (vmt->claim_oops_do(is_par, cp))
3909 + if (vmt->claim_oops_do(is_par, cp)) {
3909 3910 vmt->oops_do(f, cf);
3911 + }
3910 3912 }
3911 3913
3912 3914 #ifndef SERIALGC
3913 3915 // Used by ParallelScavenge
3914 3916 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
3915 3917 ALL_JAVA_THREADS(p) {
3916 3918 q->enqueue(new ThreadRootsTask(p));
3917 3919 }
3918 3920 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
3919 3921 }
3920 3922
3921 3923 // Used by Parallel Old
3922 3924 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
3923 3925 ALL_JAVA_THREADS(p) {
3924 3926 q->enqueue(new ThreadRootsMarkingTask(p));
3925 3927 }
3926 3928 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
3927 3929 }
3928 3930 #endif // SERIALGC
3929 3931
3930 3932 void Threads::nmethods_do(CodeBlobClosure* cf) {
3931 3933 ALL_JAVA_THREADS(p) {
3932 3934 p->nmethods_do(cf);
3933 3935 }
3934 3936 VMThread::vm_thread()->nmethods_do(cf);
3935 3937 }
3936 3938
3937 3939 void Threads::gc_epilogue() {
3938 3940 ALL_JAVA_THREADS(p) {
3939 3941 p->gc_epilogue();
3940 3942 }
3941 3943 }
3942 3944
3943 3945 void Threads::gc_prologue() {
3944 3946 ALL_JAVA_THREADS(p) {
3945 3947 p->gc_prologue();
3946 3948 }
3947 3949 }
3948 3950
3949 3951 void Threads::deoptimized_wrt_marked_nmethods() {
3950 3952 ALL_JAVA_THREADS(p) {
3951 3953 p->deoptimized_wrt_marked_nmethods();
3952 3954 }
3953 3955 }
3954 3956
3955 3957
3956 3958 // Get count Java threads that are waiting to enter the specified monitor.
3957 3959 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
3958 3960 address monitor, bool doLock) {
3959 3961 assert(doLock || SafepointSynchronize::is_at_safepoint(),
3960 3962 "must grab Threads_lock or be at safepoint");
3961 3963 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
3962 3964
3963 3965 int i = 0;
3964 3966 {
3965 3967 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3966 3968 ALL_JAVA_THREADS(p) {
3967 3969 if (p->is_Compiler_thread()) continue;
3968 3970
3969 3971 address pending = (address)p->current_pending_monitor();
3970 3972 if (pending == monitor) { // found a match
3971 3973 if (i < count) result->append(p); // save the first count matches
3972 3974 i++;
3973 3975 }
3974 3976 }
3975 3977 }
3976 3978 return result;
3977 3979 }
3978 3980
3979 3981
3980 3982 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
3981 3983 assert(doLock ||
3982 3984 Threads_lock->owned_by_self() ||
3983 3985 SafepointSynchronize::is_at_safepoint(),
3984 3986 "must grab Threads_lock or be at safepoint");
3985 3987
3986 3988 // NULL owner means not locked so we can skip the search
3987 3989 if (owner == NULL) return NULL;
3988 3990
3989 3991 {
3990 3992 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3991 3993 ALL_JAVA_THREADS(p) {
3992 3994 // first, see if owner is the address of a Java thread
3993 3995 if (owner == (address)p) return p;
3994 3996 }
3995 3997 }
3996 3998 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
3997 3999 if (UseHeavyMonitors) return NULL;
3998 4000
3999 4001 //
4000 4002 // If we didn't find a matching Java thread and we didn't force use of
4001 4003 // heavyweight monitors, then the owner is the stack address of the
4002 4004 // Lock Word in the owning Java thread's stack.
4003 4005 //
4004 4006 JavaThread* the_owner = NULL;
4005 4007 {
4006 4008 MutexLockerEx ml(doLock ? Threads_lock : NULL);
4007 4009 ALL_JAVA_THREADS(q) {
4008 4010 if (q->is_lock_owned(owner)) {
4009 4011 the_owner = q;
4010 4012 break;
4011 4013 }
4012 4014 }
4013 4015 }
4014 4016 assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
4015 4017 return the_owner;
4016 4018 }
4017 4019
4018 4020 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
4019 4021 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
4020 4022 char buf[32];
4021 4023 st->print_cr(os::local_time_string(buf, sizeof(buf)));
4022 4024
4023 4025 st->print_cr("Full thread dump %s (%s %s):",
4024 4026 Abstract_VM_Version::vm_name(),
4025 4027 Abstract_VM_Version::vm_release(),
4026 4028 Abstract_VM_Version::vm_info_string()
4027 4029 );
4028 4030 st->cr();
4029 4031
4030 4032 #ifndef SERIALGC
4031 4033 // Dump concurrent locks
4032 4034 ConcurrentLocksDump concurrent_locks;
4033 4035 if (print_concurrent_locks) {
4034 4036 concurrent_locks.dump_at_safepoint();
4035 4037 }
4036 4038 #endif // SERIALGC
4037 4039
4038 4040 ALL_JAVA_THREADS(p) {
4039 4041 ResourceMark rm;
4040 4042 p->print_on(st);
4041 4043 if (print_stacks) {
4042 4044 if (internal_format) {
4043 4045 p->trace_stack();
4044 4046 } else {
4045 4047 p->print_stack_on(st);
4046 4048 }
4047 4049 }
4048 4050 st->cr();
4049 4051 #ifndef SERIALGC
4050 4052 if (print_concurrent_locks) {
4051 4053 concurrent_locks.print_locks_on(p, st);
4052 4054 }
4053 4055 #endif // SERIALGC
4054 4056 }
4055 4057
4056 4058 VMThread::vm_thread()->print_on(st);
4057 4059 st->cr();
4058 4060 Universe::heap()->print_gc_threads_on(st);
4059 4061 WatcherThread* wt = WatcherThread::watcher_thread();
4060 4062 if (wt != NULL) wt->print_on(st);
4061 4063 st->cr();
4062 4064 CompileBroker::print_compiler_threads_on(st);
4063 4065 st->flush();
4064 4066 }
4065 4067
4066 4068 // Threads::print_on_error() is called by fatal error handler. It's possible
4067 4069 // that VM is not at safepoint and/or current thread is inside signal handler.
4068 4070 // Don't print stack trace, as the stack may not be walkable. Don't allocate
4069 4071 // memory (even in resource area), it might deadlock the error handler.
4070 4072 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
4071 4073 bool found_current = false;
4072 4074 st->print_cr("Java Threads: ( => current thread )");
4073 4075 ALL_JAVA_THREADS(thread) {
4074 4076 bool is_current = (current == thread);
4075 4077 found_current = found_current || is_current;
4076 4078
4077 4079 st->print("%s", is_current ? "=>" : " ");
4078 4080
4079 4081 st->print(PTR_FORMAT, thread);
4080 4082 st->print(" ");
4081 4083 thread->print_on_error(st, buf, buflen);
4082 4084 st->cr();
4083 4085 }
4084 4086 st->cr();
4085 4087
4086 4088 st->print_cr("Other Threads:");
4087 4089 if (VMThread::vm_thread()) {
4088 4090 bool is_current = (current == VMThread::vm_thread());
4089 4091 found_current = found_current || is_current;
4090 4092 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4091 4093
4092 4094 st->print(PTR_FORMAT, VMThread::vm_thread());
4093 4095 st->print(" ");
4094 4096 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4095 4097 st->cr();
4096 4098 }
4097 4099 WatcherThread* wt = WatcherThread::watcher_thread();
4098 4100 if (wt != NULL) {
4099 4101 bool is_current = (current == wt);
4100 4102 found_current = found_current || is_current;
4101 4103 st->print("%s", is_current ? "=>" : " ");
4102 4104
4103 4105 st->print(PTR_FORMAT, wt);
4104 4106 st->print(" ");
4105 4107 wt->print_on_error(st, buf, buflen);
4106 4108 st->cr();
4107 4109 }
4108 4110 if (!found_current) {
4109 4111 st->cr();
4110 4112 st->print("=>" PTR_FORMAT " (exited) ", current);
4111 4113 current->print_on_error(st, buf, buflen);
4112 4114 st->cr();
4113 4115 }
4114 4116 }
4115 4117
4116 4118 // Internal SpinLock and Mutex
4117 4119 // Based on ParkEvent
4118 4120
4119 4121 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4120 4122 //
4121 4123 // We employ SpinLocks _only for low-contention, fixed-length
4122 4124 // short-duration critical sections where we're concerned
4123 4125 // about native mutex_t or HotSpot Mutex:: latency.
4124 4126 // The mux construct provides a spin-then-block mutual exclusion
4125 4127 // mechanism.
4126 4128 //
4127 4129 // Testing has shown that contention on the ListLock guarding gFreeList
4128 4130 // is common. If we implement ListLock as a simple SpinLock it's common
4129 4131 // for the JVM to devolve to yielding with little progress. This is true
4130 4132 // despite the fact that the critical sections protected by ListLock are
4131 4133 // extremely short.
4132 4134 //
4133 4135 // TODO-FIXME: ListLock should be of type SpinLock.
4134 4136 // We should make this a 1st-class type, integrated into the lock
4135 4137 // hierarchy as leaf-locks. Critically, the SpinLock structure
4136 4138 // should have sufficient padding to avoid false-sharing and excessive
4137 4139 // cache-coherency traffic.
4138 4140
4139 4141
4140 4142 typedef volatile int SpinLockT ;
4141 4143
4142 4144 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4143 4145 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4144 4146 return ; // normal fast-path return
4145 4147 }
4146 4148
4147 4149 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4148 4150 TEVENT (SpinAcquire - ctx) ;
4149 4151 int ctr = 0 ;
4150 4152 int Yields = 0 ;
4151 4153 for (;;) {
4152 4154 while (*adr != 0) {
4153 4155 ++ctr ;
4154 4156 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4155 4157 if (Yields > 5) {
4156 4158 // Consider using a simple NakedSleep() instead.
4157 4159 // Then SpinAcquire could be called by non-JVM threads
4158 4160 Thread::current()->_ParkEvent->park(1) ;
4159 4161 } else {
4160 4162 os::NakedYield() ;
4161 4163 ++Yields ;
4162 4164 }
4163 4165 } else {
4164 4166 SpinPause() ;
4165 4167 }
4166 4168 }
4167 4169 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4168 4170 }
4169 4171 }
4170 4172
4171 4173 void Thread::SpinRelease (volatile int * adr) {
4172 4174 assert (*adr != 0, "invariant") ;
4173 4175 OrderAccess::fence() ; // guarantee at least release consistency.
4174 4176 // Roach-motel semantics.
4175 4177 // It's safe if subsequent LDs and STs float "up" into the critical section,
4176 4178 // but prior LDs and STs within the critical section can't be allowed
4177 4179 // to reorder or float past the ST that releases the lock.
4178 4180 *adr = 0 ;
4179 4181 }
4180 4182
4181 4183 // muxAcquire and muxRelease:
4182 4184 //
4183 4185 // * muxAcquire and muxRelease support a single-word lock-word construct.
4184 4186 // The LSB of the word is set IFF the lock is held.
4185 4187 // The remainder of the word points to the head of a singly-linked list
4186 4188 // of threads blocked on the lock.
4187 4189 //
4188 4190 // * The current implementation of muxAcquire-muxRelease uses its own
4189 4191 // dedicated Thread._MuxEvent instance. If we're interested in
4190 4192 // minimizing the peak number of extant ParkEvent instances then
4191 4193 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4192 4194 // as certain invariants were satisfied. Specifically, care would need
4193 4195 // to be taken with regards to consuming unpark() "permits".
4194 4196 // A safe rule of thumb is that a thread would never call muxAcquire()
4195 4197 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4196 4198 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4197 4199 // consume an unpark() permit intended for monitorenter, for instance.
4198 4200 // One way around this would be to widen the restricted-range semaphore
4199 4201 // implemented in park(). Another alternative would be to provide
4200 4202 // multiple instances of the PlatformEvent() for each thread. One
4201 4203 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4202 4204 //
4203 4205 // * Usage:
4204 4206 // -- Only as leaf locks
4205 4207 // -- for short-term locking only as muxAcquire does not perform
4206 4208 // thread state transitions.
4207 4209 //
4208 4210 // Alternatives:
4209 4211 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4210 4212 // but with parking or spin-then-park instead of pure spinning.
4211 4213 // * Use Taura-Oyama-Yonenzawa locks.
4212 4214 // * It's possible to construct a 1-0 lock if we encode the lockword as
4213 4215 // (List,LockByte). Acquire will CAS the full lockword while Release
4214 4216 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4215 4217 // acquiring threads use timers (ParkTimed) to detect and recover from
4216 4218 // the stranding window. Thread/Node structures must be aligned on 256-byte
4217 4219 // boundaries by using placement-new.
4218 4220 // * Augment MCS with advisory back-link fields maintained with CAS().
4219 4221 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4220 4222 // The validity of the backlinks must be ratified before we trust the value.
4221 4223 // If the backlinks are invalid the exiting thread must back-track through the
4222 4224 // the forward links, which are always trustworthy.
4223 4225 // * Add a successor indication. The LockWord is currently encoded as
4224 4226 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4225 4227 // to provide the usual futile-wakeup optimization.
4226 4228 // See RTStt for details.
4227 4229 // * Consider schedctl.sc_nopreempt to cover the critical section.
4228 4230 //
4229 4231
4230 4232
4231 4233 typedef volatile intptr_t MutexT ; // Mux Lock-word
4232 4234 enum MuxBits { LOCKBIT = 1 } ;
4233 4235
4234 4236 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4235 4237 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4236 4238 if (w == 0) return ;
4237 4239 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4238 4240 return ;
4239 4241 }
4240 4242
4241 4243 TEVENT (muxAcquire - Contention) ;
4242 4244 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4243 4245 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4244 4246 for (;;) {
4245 4247 int its = (os::is_MP() ? 100 : 0) + 1 ;
4246 4248
4247 4249 // Optional spin phase: spin-then-park strategy
4248 4250 while (--its >= 0) {
4249 4251 w = *Lock ;
4250 4252 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4251 4253 return ;
4252 4254 }
4253 4255 }
4254 4256
4255 4257 Self->reset() ;
4256 4258 Self->OnList = intptr_t(Lock) ;
4257 4259 // The following fence() isn't _strictly necessary as the subsequent
4258 4260 // CAS() both serializes execution and ratifies the fetched *Lock value.
4259 4261 OrderAccess::fence();
4260 4262 for (;;) {
4261 4263 w = *Lock ;
4262 4264 if ((w & LOCKBIT) == 0) {
4263 4265 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4264 4266 Self->OnList = 0 ; // hygiene - allows stronger asserts
4265 4267 return ;
4266 4268 }
4267 4269 continue ; // Interference -- *Lock changed -- Just retry
4268 4270 }
4269 4271 assert (w & LOCKBIT, "invariant") ;
4270 4272 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4271 4273 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4272 4274 }
4273 4275
4274 4276 while (Self->OnList != 0) {
4275 4277 Self->park() ;
4276 4278 }
4277 4279 }
4278 4280 }
4279 4281
4280 4282 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4281 4283 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4282 4284 if (w == 0) return ;
4283 4285 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4284 4286 return ;
4285 4287 }
4286 4288
4287 4289 TEVENT (muxAcquire - Contention) ;
4288 4290 ParkEvent * ReleaseAfter = NULL ;
4289 4291 if (ev == NULL) {
4290 4292 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4291 4293 }
4292 4294 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4293 4295 for (;;) {
4294 4296 guarantee (ev->OnList == 0, "invariant") ;
4295 4297 int its = (os::is_MP() ? 100 : 0) + 1 ;
4296 4298
4297 4299 // Optional spin phase: spin-then-park strategy
4298 4300 while (--its >= 0) {
4299 4301 w = *Lock ;
4300 4302 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4301 4303 if (ReleaseAfter != NULL) {
4302 4304 ParkEvent::Release (ReleaseAfter) ;
4303 4305 }
4304 4306 return ;
4305 4307 }
4306 4308 }
4307 4309
4308 4310 ev->reset() ;
4309 4311 ev->OnList = intptr_t(Lock) ;
4310 4312 // The following fence() isn't _strictly necessary as the subsequent
4311 4313 // CAS() both serializes execution and ratifies the fetched *Lock value.
4312 4314 OrderAccess::fence();
4313 4315 for (;;) {
4314 4316 w = *Lock ;
4315 4317 if ((w & LOCKBIT) == 0) {
4316 4318 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4317 4319 ev->OnList = 0 ;
4318 4320 // We call ::Release while holding the outer lock, thus
4319 4321 // artificially lengthening the critical section.
4320 4322 // Consider deferring the ::Release() until the subsequent unlock(),
4321 4323 // after we've dropped the outer lock.
4322 4324 if (ReleaseAfter != NULL) {
4323 4325 ParkEvent::Release (ReleaseAfter) ;
4324 4326 }
4325 4327 return ;
4326 4328 }
4327 4329 continue ; // Interference -- *Lock changed -- Just retry
4328 4330 }
4329 4331 assert (w & LOCKBIT, "invariant") ;
4330 4332 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4331 4333 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4332 4334 }
4333 4335
4334 4336 while (ev->OnList != 0) {
4335 4337 ev->park() ;
4336 4338 }
4337 4339 }
4338 4340 }
4339 4341
4340 4342 // Release() must extract a successor from the list and then wake that thread.
4341 4343 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4342 4344 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4343 4345 // Release() would :
4344 4346 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4345 4347 // (B) Extract a successor from the private list "in-hand"
4346 4348 // (C) attempt to CAS() the residual back into *Lock over null.
4347 4349 // If there were any newly arrived threads and the CAS() would fail.
4348 4350 // In that case Release() would detach the RATs, re-merge the list in-hand
4349 4351 // with the RATs and repeat as needed. Alternately, Release() might
4350 4352 // detach and extract a successor, but then pass the residual list to the wakee.
4351 4353 // The wakee would be responsible for reattaching and remerging before it
4352 4354 // competed for the lock.
4353 4355 //
4354 4356 // Both "pop" and DMR are immune from ABA corruption -- there can be
4355 4357 // multiple concurrent pushers, but only one popper or detacher.
4356 4358 // This implementation pops from the head of the list. This is unfair,
4357 4359 // but tends to provide excellent throughput as hot threads remain hot.
4358 4360 // (We wake recently run threads first).
4359 4361
4360 4362 void Thread::muxRelease (volatile intptr_t * Lock) {
4361 4363 for (;;) {
4362 4364 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4363 4365 assert (w & LOCKBIT, "invariant") ;
4364 4366 if (w == LOCKBIT) return ;
4365 4367 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4366 4368 assert (List != NULL, "invariant") ;
4367 4369 assert (List->OnList == intptr_t(Lock), "invariant") ;
4368 4370 ParkEvent * nxt = List->ListNext ;
4369 4371
4370 4372 // The following CAS() releases the lock and pops the head element.
4371 4373 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4372 4374 continue ;
4373 4375 }
4374 4376 List->OnList = 0 ;
4375 4377 OrderAccess::fence() ;
4376 4378 List->unpark () ;
4377 4379 return ;
4378 4380 }
4379 4381 }
4380 4382
4381 4383
4382 4384 void Threads::verify() {
4383 4385 ALL_JAVA_THREADS(p) {
4384 4386 p->verify();
4385 4387 }
4386 4388 VMThread* thread = VMThread::vm_thread();
4387 4389 if (thread != NULL) thread->verify();
4388 4390 }
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