Print this page
| Split |
Close |
| Expand all |
| Collapse all |
--- 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 "jvmtifiles/jvmtiEnv.hpp"
35 35 #include "memory/oopFactory.hpp"
36 36 #include "memory/universe.inline.hpp"
37 37 #include "oops/instanceKlass.hpp"
38 38 #include "oops/objArrayOop.hpp"
39 39 #include "oops/oop.inline.hpp"
40 40 #include "oops/symbol.hpp"
41 41 #include "prims/jvm_misc.hpp"
42 42 #include "prims/jvmtiExport.hpp"
43 43 #include "prims/jvmtiThreadState.hpp"
44 44 #include "prims/privilegedStack.hpp"
45 45 #include "runtime/aprofiler.hpp"
46 46 #include "runtime/arguments.hpp"
47 47 #include "runtime/biasedLocking.hpp"
48 48 #include "runtime/deoptimization.hpp"
49 49 #include "runtime/fprofiler.hpp"
50 50 #include "runtime/frame.inline.hpp"
51 51 #include "runtime/init.hpp"
52 52 #include "runtime/interfaceSupport.hpp"
53 53 #include "runtime/java.hpp"
54 54 #include "runtime/javaCalls.hpp"
55 55 #include "runtime/jniPeriodicChecker.hpp"
56 56 #include "runtime/memprofiler.hpp"
57 57 #include "runtime/mutexLocker.hpp"
58 58 #include "runtime/objectMonitor.hpp"
59 59 #include "runtime/osThread.hpp"
60 60 #include "runtime/safepoint.hpp"
61 61 #include "runtime/sharedRuntime.hpp"
62 62 #include "runtime/statSampler.hpp"
63 63 #include "runtime/stubRoutines.hpp"
64 64 #include "runtime/task.hpp"
65 65 #include "runtime/threadCritical.hpp"
66 66 #include "runtime/threadLocalStorage.hpp"
67 67 #include "runtime/vframe.hpp"
68 68 #include "runtime/vframeArray.hpp"
69 69 #include "runtime/vframe_hp.hpp"
70 70 #include "runtime/vmThread.hpp"
71 71 #include "runtime/vm_operations.hpp"
72 72 #include "services/attachListener.hpp"
73 73 #include "services/management.hpp"
74 74 #include "services/threadService.hpp"
75 75 #include "utilities/defaultStream.hpp"
76 76 #include "utilities/dtrace.hpp"
77 77 #include "utilities/events.hpp"
78 78 #include "utilities/preserveException.hpp"
79 79 #ifdef TARGET_OS_FAMILY_linux
80 80 # include "os_linux.inline.hpp"
81 81 # include "thread_linux.inline.hpp"
82 82 #endif
83 83 #ifdef TARGET_OS_FAMILY_solaris
84 84 # include "os_solaris.inline.hpp"
85 85 # include "thread_solaris.inline.hpp"
86 86 #endif
87 87 #ifdef TARGET_OS_FAMILY_windows
88 88 # include "os_windows.inline.hpp"
89 89 # include "thread_windows.inline.hpp"
90 90 #endif
91 91 #ifndef SERIALGC
92 92 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
93 93 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
94 94 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
95 95 #endif
96 96 #ifdef COMPILER1
97 97 #include "c1/c1_Compiler.hpp"
98 98 #endif
99 99 #ifdef COMPILER2
100 100 #include "opto/c2compiler.hpp"
101 101 #include "opto/idealGraphPrinter.hpp"
102 102 #endif
103 103
104 104 #ifdef DTRACE_ENABLED
105 105
106 106 // Only bother with this argument setup if dtrace is available
107 107
108 108 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin);
109 109 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end);
110 110 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t,
111 111 intptr_t, intptr_t, bool);
112 112 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t,
113 113 intptr_t, intptr_t, bool);
114 114
115 115 #define DTRACE_THREAD_PROBE(probe, javathread) \
116 116 { \
117 117 ResourceMark rm(this); \
118 118 int len = 0; \
119 119 const char* name = (javathread)->get_thread_name(); \
120 120 len = strlen(name); \
121 121 HS_DTRACE_PROBE5(hotspot, thread__##probe, \
122 122 name, len, \
123 123 java_lang_Thread::thread_id((javathread)->threadObj()), \
124 124 (javathread)->osthread()->thread_id(), \
125 125 java_lang_Thread::is_daemon((javathread)->threadObj())); \
126 126 }
127 127
128 128 #else // ndef DTRACE_ENABLED
129 129
130 130 #define DTRACE_THREAD_PROBE(probe, javathread)
131 131
132 132 #endif // ndef DTRACE_ENABLED
133 133
134 134 // Class hierarchy
135 135 // - Thread
136 136 // - VMThread
137 137 // - WatcherThread
138 138 // - ConcurrentMarkSweepThread
139 139 // - JavaThread
140 140 // - CompilerThread
141 141
142 142 // ======= Thread ========
143 143
144 144 // Support for forcing alignment of thread objects for biased locking
145 145 void* Thread::operator new(size_t size) {
146 146 if (UseBiasedLocking) {
147 147 const int alignment = markOopDesc::biased_lock_alignment;
148 148 size_t aligned_size = size + (alignment - sizeof(intptr_t));
149 149 void* real_malloc_addr = CHeapObj::operator new(aligned_size);
150 150 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment);
151 151 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
152 152 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
153 153 "JavaThread alignment code overflowed allocated storage");
154 154 if (TraceBiasedLocking) {
155 155 if (aligned_addr != real_malloc_addr)
156 156 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
157 157 real_malloc_addr, aligned_addr);
158 158 }
159 159 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
160 160 return aligned_addr;
161 161 } else {
162 162 return CHeapObj::operator new(size);
163 163 }
164 164 }
165 165
166 166 void Thread::operator delete(void* p) {
167 167 if (UseBiasedLocking) {
168 168 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
169 169 CHeapObj::operator delete(real_malloc_addr);
170 170 } else {
171 171 CHeapObj::operator delete(p);
172 172 }
173 173 }
174 174
175 175
176 176 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
177 177 // JavaThread
178 178
179 179
180 180 Thread::Thread() {
181 181 // stack and get_thread
182 182 set_stack_base(NULL);
183 183 set_stack_size(0);
184 184 set_self_raw_id(0);
185 185 set_lgrp_id(-1);
186 186
187 187 // allocated data structures
188 188 set_osthread(NULL);
189 189 set_resource_area(new ResourceArea());
190 190 set_handle_area(new HandleArea(NULL));
191 191 set_active_handles(NULL);
192 192 set_free_handle_block(NULL);
193 193 set_last_handle_mark(NULL);
194 194
195 195 // This initial value ==> never claimed.
196 196 _oops_do_parity = 0;
197 197
198 198 // the handle mark links itself to last_handle_mark
199 199 new HandleMark(this);
200 200
201 201 // plain initialization
202 202 debug_only(_owned_locks = NULL;)
203 203 debug_only(_allow_allocation_count = 0;)
204 204 NOT_PRODUCT(_allow_safepoint_count = 0;)
205 205 NOT_PRODUCT(_skip_gcalot = false;)
206 206 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;)
207 207 _jvmti_env_iteration_count = 0;
208 208 set_allocated_bytes(0);
209 209 _vm_operation_started_count = 0;
210 210 _vm_operation_completed_count = 0;
211 211 _current_pending_monitor = NULL;
212 212 _current_pending_monitor_is_from_java = true;
213 213 _current_waiting_monitor = NULL;
214 214 _num_nested_signal = 0;
215 215 omFreeList = NULL ;
216 216 omFreeCount = 0 ;
217 217 omFreeProvision = 32 ;
218 218 omInUseList = NULL ;
219 219 omInUseCount = 0 ;
220 220
221 221 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true);
222 222 _suspend_flags = 0;
223 223
224 224 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
225 225 _hashStateX = os::random() ;
226 226 _hashStateY = 842502087 ;
227 227 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ;
228 228 _hashStateW = 273326509 ;
229 229
230 230 _OnTrap = 0 ;
231 231 _schedctl = NULL ;
232 232 _Stalled = 0 ;
233 233 _TypeTag = 0x2BAD ;
234 234
235 235 // Many of the following fields are effectively final - immutable
236 236 // Note that nascent threads can't use the Native Monitor-Mutex
237 237 // construct until the _MutexEvent is initialized ...
238 238 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
239 239 // we might instead use a stack of ParkEvents that we could provision on-demand.
240 240 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
241 241 // and ::Release()
242 242 _ParkEvent = ParkEvent::Allocate (this) ;
243 243 _SleepEvent = ParkEvent::Allocate (this) ;
244 244 _MutexEvent = ParkEvent::Allocate (this) ;
245 245 _MuxEvent = ParkEvent::Allocate (this) ;
246 246
247 247 #ifdef CHECK_UNHANDLED_OOPS
248 248 if (CheckUnhandledOops) {
249 249 _unhandled_oops = new UnhandledOops(this);
250 250 }
251 251 #endif // CHECK_UNHANDLED_OOPS
252 252 #ifdef ASSERT
253 253 if (UseBiasedLocking) {
254 254 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
255 255 assert(this == _real_malloc_address ||
256 256 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment),
257 257 "bug in forced alignment of thread objects");
258 258 }
259 259 #endif /* ASSERT */
260 260 }
261 261
262 262 void Thread::initialize_thread_local_storage() {
263 263 // Note: Make sure this method only calls
264 264 // non-blocking operations. Otherwise, it might not work
265 265 // with the thread-startup/safepoint interaction.
266 266
267 267 // During Java thread startup, safepoint code should allow this
268 268 // method to complete because it may need to allocate memory to
269 269 // store information for the new thread.
270 270
271 271 // initialize structure dependent on thread local storage
272 272 ThreadLocalStorage::set_thread(this);
273 273
274 274 // set up any platform-specific state.
275 275 os::initialize_thread();
276 276
277 277 }
278 278
279 279 void Thread::record_stack_base_and_size() {
280 280 set_stack_base(os::current_stack_base());
281 281 set_stack_size(os::current_stack_size());
282 282 }
283 283
284 284
285 285 Thread::~Thread() {
286 286 // Reclaim the objectmonitors from the omFreeList of the moribund thread.
287 287 ObjectSynchronizer::omFlush (this) ;
288 288
289 289 // deallocate data structures
290 290 delete resource_area();
291 291 // since the handle marks are using the handle area, we have to deallocated the root
292 292 // handle mark before deallocating the thread's handle area,
293 293 assert(last_handle_mark() != NULL, "check we have an element");
294 294 delete last_handle_mark();
295 295 assert(last_handle_mark() == NULL, "check we have reached the end");
296 296
297 297 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
298 298 // We NULL out the fields for good hygiene.
299 299 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ;
300 300 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ;
301 301 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ;
302 302 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ;
303 303
304 304 delete handle_area();
305 305
306 306 // osthread() can be NULL, if creation of thread failed.
307 307 if (osthread() != NULL) os::free_thread(osthread());
308 308
309 309 delete _SR_lock;
310 310
311 311 // clear thread local storage if the Thread is deleting itself
312 312 if (this == Thread::current()) {
313 313 ThreadLocalStorage::set_thread(NULL);
314 314 } else {
315 315 // In the case where we're not the current thread, invalidate all the
316 316 // caches in case some code tries to get the current thread or the
317 317 // thread that was destroyed, and gets stale information.
318 318 ThreadLocalStorage::invalidate_all();
319 319 }
320 320 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
321 321 }
322 322
323 323 // NOTE: dummy function for assertion purpose.
324 324 void Thread::run() {
325 325 ShouldNotReachHere();
326 326 }
327 327
328 328 #ifdef ASSERT
329 329 // Private method to check for dangling thread pointer
330 330 void check_for_dangling_thread_pointer(Thread *thread) {
331 331 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
332 332 "possibility of dangling Thread pointer");
333 333 }
334 334 #endif
335 335
336 336
337 337 #ifndef PRODUCT
338 338 // Tracing method for basic thread operations
339 339 void Thread::trace(const char* msg, const Thread* const thread) {
340 340 if (!TraceThreadEvents) return;
341 341 ResourceMark rm;
342 342 ThreadCritical tc;
343 343 const char *name = "non-Java thread";
344 344 int prio = -1;
345 345 if (thread->is_Java_thread()
346 346 && !thread->is_Compiler_thread()) {
347 347 // The Threads_lock must be held to get information about
348 348 // this thread but may not be in some situations when
349 349 // tracing thread events.
350 350 bool release_Threads_lock = false;
351 351 if (!Threads_lock->owned_by_self()) {
352 352 Threads_lock->lock();
353 353 release_Threads_lock = true;
354 354 }
355 355 JavaThread* jt = (JavaThread *)thread;
356 356 name = (char *)jt->get_thread_name();
357 357 oop thread_oop = jt->threadObj();
358 358 if (thread_oop != NULL) {
359 359 prio = java_lang_Thread::priority(thread_oop);
360 360 }
361 361 if (release_Threads_lock) {
362 362 Threads_lock->unlock();
363 363 }
364 364 }
365 365 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio);
366 366 }
367 367 #endif
368 368
369 369
370 370 ThreadPriority Thread::get_priority(const Thread* const thread) {
371 371 trace("get priority", thread);
372 372 ThreadPriority priority;
373 373 // Can return an error!
374 374 (void)os::get_priority(thread, priority);
375 375 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
376 376 return priority;
377 377 }
378 378
379 379 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
380 380 trace("set priority", thread);
381 381 debug_only(check_for_dangling_thread_pointer(thread);)
382 382 // Can return an error!
383 383 (void)os::set_priority(thread, priority);
384 384 }
385 385
386 386
387 387 void Thread::start(Thread* thread) {
388 388 trace("start", thread);
389 389 // Start is different from resume in that its safety is guaranteed by context or
390 390 // being called from a Java method synchronized on the Thread object.
391 391 if (!DisableStartThread) {
392 392 if (thread->is_Java_thread()) {
393 393 // Initialize the thread state to RUNNABLE before starting this thread.
394 394 // Can not set it after the thread started because we do not know the
395 395 // exact thread state at that time. It could be in MONITOR_WAIT or
396 396 // in SLEEPING or some other state.
397 397 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
398 398 java_lang_Thread::RUNNABLE);
399 399 }
400 400 os::start_thread(thread);
401 401 }
402 402 }
403 403
404 404 // Enqueue a VM_Operation to do the job for us - sometime later
405 405 void Thread::send_async_exception(oop java_thread, oop java_throwable) {
406 406 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
407 407 VMThread::execute(vm_stop);
408 408 }
409 409
410 410
411 411 //
412 412 // Check if an external suspend request has completed (or has been
413 413 // cancelled). Returns true if the thread is externally suspended and
414 414 // false otherwise.
415 415 //
416 416 // The bits parameter returns information about the code path through
417 417 // the routine. Useful for debugging:
418 418 //
419 419 // set in is_ext_suspend_completed():
420 420 // 0x00000001 - routine was entered
421 421 // 0x00000010 - routine return false at end
422 422 // 0x00000100 - thread exited (return false)
423 423 // 0x00000200 - suspend request cancelled (return false)
424 424 // 0x00000400 - thread suspended (return true)
425 425 // 0x00001000 - thread is in a suspend equivalent state (return true)
426 426 // 0x00002000 - thread is native and walkable (return true)
427 427 // 0x00004000 - thread is native_trans and walkable (needed retry)
428 428 //
429 429 // set in wait_for_ext_suspend_completion():
430 430 // 0x00010000 - routine was entered
431 431 // 0x00020000 - suspend request cancelled before loop (return false)
432 432 // 0x00040000 - thread suspended before loop (return true)
433 433 // 0x00080000 - suspend request cancelled in loop (return false)
434 434 // 0x00100000 - thread suspended in loop (return true)
435 435 // 0x00200000 - suspend not completed during retry loop (return false)
436 436 //
437 437
438 438 // Helper class for tracing suspend wait debug bits.
439 439 //
440 440 // 0x00000100 indicates that the target thread exited before it could
441 441 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
442 442 // 0x00080000 each indicate a cancelled suspend request so they don't
443 443 // count as wait failures either.
444 444 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
445 445
446 446 class TraceSuspendDebugBits : public StackObj {
447 447 private:
448 448 JavaThread * jt;
449 449 bool is_wait;
450 450 bool called_by_wait; // meaningful when !is_wait
451 451 uint32_t * bits;
452 452
453 453 public:
454 454 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
455 455 uint32_t *_bits) {
456 456 jt = _jt;
457 457 is_wait = _is_wait;
458 458 called_by_wait = _called_by_wait;
459 459 bits = _bits;
460 460 }
461 461
462 462 ~TraceSuspendDebugBits() {
463 463 if (!is_wait) {
464 464 #if 1
465 465 // By default, don't trace bits for is_ext_suspend_completed() calls.
466 466 // That trace is very chatty.
467 467 return;
468 468 #else
469 469 if (!called_by_wait) {
470 470 // If tracing for is_ext_suspend_completed() is enabled, then only
471 471 // trace calls to it from wait_for_ext_suspend_completion()
472 472 return;
473 473 }
474 474 #endif
475 475 }
476 476
477 477 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
478 478 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
479 479 MutexLocker ml(Threads_lock); // needed for get_thread_name()
480 480 ResourceMark rm;
481 481
482 482 tty->print_cr(
483 483 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
484 484 jt->get_thread_name(), *bits);
485 485
486 486 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
487 487 }
488 488 }
489 489 }
490 490 };
491 491 #undef DEBUG_FALSE_BITS
492 492
493 493
494 494 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) {
495 495 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
496 496
497 497 bool did_trans_retry = false; // only do thread_in_native_trans retry once
498 498 bool do_trans_retry; // flag to force the retry
499 499
500 500 *bits |= 0x00000001;
501 501
502 502 do {
503 503 do_trans_retry = false;
504 504
505 505 if (is_exiting()) {
506 506 // Thread is in the process of exiting. This is always checked
507 507 // first to reduce the risk of dereferencing a freed JavaThread.
508 508 *bits |= 0x00000100;
509 509 return false;
510 510 }
511 511
512 512 if (!is_external_suspend()) {
513 513 // Suspend request is cancelled. This is always checked before
514 514 // is_ext_suspended() to reduce the risk of a rogue resume
515 515 // confusing the thread that made the suspend request.
516 516 *bits |= 0x00000200;
517 517 return false;
518 518 }
519 519
520 520 if (is_ext_suspended()) {
521 521 // thread is suspended
522 522 *bits |= 0x00000400;
523 523 return true;
524 524 }
525 525
526 526 // Now that we no longer do hard suspends of threads running
527 527 // native code, the target thread can be changing thread state
528 528 // while we are in this routine:
529 529 //
530 530 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked
531 531 //
532 532 // We save a copy of the thread state as observed at this moment
533 533 // and make our decision about suspend completeness based on the
534 534 // copy. This closes the race where the thread state is seen as
535 535 // _thread_in_native_trans in the if-thread_blocked check, but is
536 536 // seen as _thread_blocked in if-thread_in_native_trans check.
537 537 JavaThreadState save_state = thread_state();
538 538
539 539 if (save_state == _thread_blocked && is_suspend_equivalent()) {
540 540 // If the thread's state is _thread_blocked and this blocking
541 541 // condition is known to be equivalent to a suspend, then we can
542 542 // consider the thread to be externally suspended. This means that
543 543 // the code that sets _thread_blocked has been modified to do
544 544 // self-suspension if the blocking condition releases. We also
545 545 // used to check for CONDVAR_WAIT here, but that is now covered by
546 546 // the _thread_blocked with self-suspension check.
547 547 //
548 548 // Return true since we wouldn't be here unless there was still an
549 549 // external suspend request.
550 550 *bits |= 0x00001000;
551 551 return true;
552 552 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
553 553 // Threads running native code will self-suspend on native==>VM/Java
554 554 // transitions. If its stack is walkable (should always be the case
555 555 // unless this function is called before the actual java_suspend()
556 556 // call), then the wait is done.
557 557 *bits |= 0x00002000;
558 558 return true;
559 559 } else if (!called_by_wait && !did_trans_retry &&
560 560 save_state == _thread_in_native_trans &&
561 561 frame_anchor()->walkable()) {
562 562 // The thread is transitioning from thread_in_native to another
563 563 // thread state. check_safepoint_and_suspend_for_native_trans()
564 564 // will force the thread to self-suspend. If it hasn't gotten
565 565 // there yet we may have caught the thread in-between the native
566 566 // code check above and the self-suspend. Lucky us. If we were
567 567 // called by wait_for_ext_suspend_completion(), then it
568 568 // will be doing the retries so we don't have to.
569 569 //
570 570 // Since we use the saved thread state in the if-statement above,
571 571 // there is a chance that the thread has already transitioned to
572 572 // _thread_blocked by the time we get here. In that case, we will
573 573 // make a single unnecessary pass through the logic below. This
574 574 // doesn't hurt anything since we still do the trans retry.
575 575
576 576 *bits |= 0x00004000;
577 577
578 578 // Once the thread leaves thread_in_native_trans for another
579 579 // thread state, we break out of this retry loop. We shouldn't
580 580 // need this flag to prevent us from getting back here, but
581 581 // sometimes paranoia is good.
582 582 did_trans_retry = true;
583 583
584 584 // We wait for the thread to transition to a more usable state.
585 585 for (int i = 1; i <= SuspendRetryCount; i++) {
586 586 // We used to do an "os::yield_all(i)" call here with the intention
587 587 // that yielding would increase on each retry. However, the parameter
588 588 // is ignored on Linux which means the yield didn't scale up. Waiting
589 589 // on the SR_lock below provides a much more predictable scale up for
590 590 // the delay. It also provides a simple/direct point to check for any
591 591 // safepoint requests from the VMThread
592 592
593 593 // temporarily drops SR_lock while doing wait with safepoint check
594 594 // (if we're a JavaThread - the WatcherThread can also call this)
595 595 // and increase delay with each retry
596 596 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
597 597
598 598 // check the actual thread state instead of what we saved above
599 599 if (thread_state() != _thread_in_native_trans) {
600 600 // the thread has transitioned to another thread state so
601 601 // try all the checks (except this one) one more time.
602 602 do_trans_retry = true;
603 603 break;
604 604 }
605 605 } // end retry loop
606 606
607 607
608 608 }
609 609 } while (do_trans_retry);
610 610
611 611 *bits |= 0x00000010;
612 612 return false;
613 613 }
614 614
615 615 //
616 616 // Wait for an external suspend request to complete (or be cancelled).
617 617 // Returns true if the thread is externally suspended and false otherwise.
618 618 //
619 619 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
620 620 uint32_t *bits) {
621 621 TraceSuspendDebugBits tsdb(this, true /* is_wait */,
622 622 false /* !called_by_wait */, bits);
623 623
624 624 // local flag copies to minimize SR_lock hold time
625 625 bool is_suspended;
626 626 bool pending;
627 627 uint32_t reset_bits;
628 628
629 629 // set a marker so is_ext_suspend_completed() knows we are the caller
630 630 *bits |= 0x00010000;
631 631
632 632 // We use reset_bits to reinitialize the bits value at the top of
633 633 // each retry loop. This allows the caller to make use of any
634 634 // unused bits for their own marking purposes.
635 635 reset_bits = *bits;
636 636
637 637 {
638 638 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
639 639 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
640 640 delay, bits);
641 641 pending = is_external_suspend();
642 642 }
643 643 // must release SR_lock to allow suspension to complete
644 644
645 645 if (!pending) {
646 646 // A cancelled suspend request is the only false return from
647 647 // is_ext_suspend_completed() that keeps us from entering the
648 648 // retry loop.
649 649 *bits |= 0x00020000;
650 650 return false;
651 651 }
652 652
653 653 if (is_suspended) {
654 654 *bits |= 0x00040000;
655 655 return true;
656 656 }
657 657
658 658 for (int i = 1; i <= retries; i++) {
659 659 *bits = reset_bits; // reinit to only track last retry
660 660
661 661 // We used to do an "os::yield_all(i)" call here with the intention
662 662 // that yielding would increase on each retry. However, the parameter
663 663 // is ignored on Linux which means the yield didn't scale up. Waiting
664 664 // on the SR_lock below provides a much more predictable scale up for
665 665 // the delay. It also provides a simple/direct point to check for any
666 666 // safepoint requests from the VMThread
667 667
668 668 {
669 669 MutexLocker ml(SR_lock());
670 670 // wait with safepoint check (if we're a JavaThread - the WatcherThread
671 671 // can also call this) and increase delay with each retry
672 672 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
673 673
674 674 is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
675 675 delay, bits);
676 676
677 677 // It is possible for the external suspend request to be cancelled
678 678 // (by a resume) before the actual suspend operation is completed.
679 679 // Refresh our local copy to see if we still need to wait.
680 680 pending = is_external_suspend();
681 681 }
682 682
683 683 if (!pending) {
684 684 // A cancelled suspend request is the only false return from
685 685 // is_ext_suspend_completed() that keeps us from staying in the
686 686 // retry loop.
687 687 *bits |= 0x00080000;
688 688 return false;
689 689 }
690 690
691 691 if (is_suspended) {
692 692 *bits |= 0x00100000;
693 693 return true;
694 694 }
695 695 } // end retry loop
696 696
697 697 // thread did not suspend after all our retries
698 698 *bits |= 0x00200000;
699 699 return false;
700 700 }
701 701
702 702 #ifndef PRODUCT
703 703 void JavaThread::record_jump(address target, address instr, const char* file, int line) {
704 704
705 705 // This should not need to be atomic as the only way for simultaneous
706 706 // updates is via interrupts. Even then this should be rare or non-existant
707 707 // and we don't care that much anyway.
708 708
709 709 int index = _jmp_ring_index;
710 710 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1);
711 711 _jmp_ring[index]._target = (intptr_t) target;
712 712 _jmp_ring[index]._instruction = (intptr_t) instr;
713 713 _jmp_ring[index]._file = file;
714 714 _jmp_ring[index]._line = line;
715 715 }
716 716 #endif /* PRODUCT */
717 717
718 718 // Called by flat profiler
719 719 // Callers have already called wait_for_ext_suspend_completion
720 720 // The assertion for that is currently too complex to put here:
721 721 bool JavaThread::profile_last_Java_frame(frame* _fr) {
722 722 bool gotframe = false;
723 723 // self suspension saves needed state.
724 724 if (has_last_Java_frame() && _anchor.walkable()) {
725 725 *_fr = pd_last_frame();
726 726 gotframe = true;
727 727 }
728 728 return gotframe;
729 729 }
730 730
731 731 void Thread::interrupt(Thread* thread) {
732 732 trace("interrupt", thread);
733 733 debug_only(check_for_dangling_thread_pointer(thread);)
734 734 os::interrupt(thread);
735 735 }
736 736
737 737 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
738 738 trace("is_interrupted", thread);
739 739 debug_only(check_for_dangling_thread_pointer(thread);)
740 740 // Note: If clear_interrupted==false, this simply fetches and
741 741 // returns the value of the field osthread()->interrupted().
742 742 return os::is_interrupted(thread, clear_interrupted);
743 743 }
744 744
745 745
746 746 // GC Support
747 747 bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
748 748 jint thread_parity = _oops_do_parity;
749 749 if (thread_parity != strong_roots_parity) {
750 750 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
751 751 if (res == thread_parity) return true;
752 752 else {
753 753 guarantee(res == strong_roots_parity, "Or else what?");
754 754 assert(SharedHeap::heap()->n_par_threads() > 0,
755 755 "Should only fail when parallel.");
756 756 return false;
757 757 }
758 758 }
759 759 assert(SharedHeap::heap()->n_par_threads() > 0,
760 760 "Should only fail when parallel.");
761 761 return false;
762 762 }
763 763
764 764 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
765 765 active_handles()->oops_do(f);
766 766 // Do oop for ThreadShadow
767 767 f->do_oop((oop*)&_pending_exception);
768 768 handle_area()->oops_do(f);
769 769 }
770 770
771 771 void Thread::nmethods_do(CodeBlobClosure* cf) {
772 772 // no nmethods in a generic thread...
773 773 }
774 774
775 775 void Thread::print_on(outputStream* st) const {
776 776 // get_priority assumes osthread initialized
777 777 if (osthread() != NULL) {
778 778 st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this);
779 779 osthread()->print_on(st);
780 780 }
781 781 debug_only(if (WizardMode) print_owned_locks_on(st);)
782 782 }
783 783
784 784 // Thread::print_on_error() is called by fatal error handler. Don't use
785 785 // any lock or allocate memory.
786 786 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
787 787 if (is_VM_thread()) st->print("VMThread");
788 788 else if (is_Compiler_thread()) st->print("CompilerThread");
789 789 else if (is_Java_thread()) st->print("JavaThread");
790 790 else if (is_GC_task_thread()) st->print("GCTaskThread");
791 791 else if (is_Watcher_thread()) st->print("WatcherThread");
792 792 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread");
793 793 else st->print("Thread");
794 794
795 795 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
796 796 _stack_base - _stack_size, _stack_base);
797 797
798 798 if (osthread()) {
799 799 st->print(" [id=%d]", osthread()->thread_id());
800 800 }
801 801 }
802 802
803 803 #ifdef ASSERT
804 804 void Thread::print_owned_locks_on(outputStream* st) const {
805 805 Monitor *cur = _owned_locks;
806 806 if (cur == NULL) {
807 807 st->print(" (no locks) ");
808 808 } else {
809 809 st->print_cr(" Locks owned:");
810 810 while(cur) {
811 811 cur->print_on(st);
812 812 cur = cur->next();
813 813 }
814 814 }
815 815 }
816 816
817 817 static int ref_use_count = 0;
818 818
819 819 bool Thread::owns_locks_but_compiled_lock() const {
820 820 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
821 821 if (cur != Compile_lock) return true;
822 822 }
823 823 return false;
824 824 }
825 825
826 826
827 827 #endif
828 828
829 829 #ifndef PRODUCT
830 830
831 831 // The flag: potential_vm_operation notifies if this particular safepoint state could potential
832 832 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
833 833 // no threads which allow_vm_block's are held
834 834 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
835 835 // Check if current thread is allowed to block at a safepoint
836 836 if (!(_allow_safepoint_count == 0))
837 837 fatal("Possible safepoint reached by thread that does not allow it");
838 838 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
839 839 fatal("LEAF method calling lock?");
840 840 }
841 841
842 842 #ifdef ASSERT
843 843 if (potential_vm_operation && is_Java_thread()
844 844 && !Universe::is_bootstrapping()) {
845 845 // Make sure we do not hold any locks that the VM thread also uses.
846 846 // This could potentially lead to deadlocks
847 847 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) {
848 848 // Threads_lock is special, since the safepoint synchronization will not start before this is
849 849 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
850 850 // since it is used to transfer control between JavaThreads and the VMThread
851 851 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first!
852 852 if ( (cur->allow_vm_block() &&
853 853 cur != Threads_lock &&
854 854 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation
855 855 cur != VMOperationRequest_lock &&
856 856 cur != VMOperationQueue_lock) ||
857 857 cur->rank() == Mutex::special) {
858 858 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name());
859 859 }
860 860 }
861 861 }
862 862
863 863 if (GCALotAtAllSafepoints) {
864 864 // We could enter a safepoint here and thus have a gc
865 865 InterfaceSupport::check_gc_alot();
866 866 }
867 867 #endif
868 868 }
869 869 #endif
870 870
871 871 bool Thread::is_in_stack(address adr) const {
872 872 assert(Thread::current() == this, "is_in_stack can only be called from current thread");
873 873 address end = os::current_stack_pointer();
874 874 if (stack_base() >= adr && adr >= end) return true;
875 875
876 876 return false;
877 877 }
878 878
879 879
880 880 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
881 881 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
882 882 // used for compilation in the future. If that change is made, the need for these methods
883 883 // should be revisited, and they should be removed if possible.
884 884
885 885 bool Thread::is_lock_owned(address adr) const {
886 886 return on_local_stack(adr);
887 887 }
888 888
889 889 bool Thread::set_as_starting_thread() {
890 890 // NOTE: this must be called inside the main thread.
891 891 return os::create_main_thread((JavaThread*)this);
892 892 }
893 893
894 894 static void initialize_class(Symbol* class_name, TRAPS) {
895 895 klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
896 896 instanceKlass::cast(klass)->initialize(CHECK);
897 897 }
898 898
899 899
900 900 // Creates the initial ThreadGroup
901 901 static Handle create_initial_thread_group(TRAPS) {
902 902 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
903 903 instanceKlassHandle klass (THREAD, k);
904 904
905 905 Handle system_instance = klass->allocate_instance_handle(CHECK_NH);
906 906 {
907 907 JavaValue result(T_VOID);
908 908 JavaCalls::call_special(&result,
909 909 system_instance,
910 910 klass,
911 911 vmSymbols::object_initializer_name(),
912 912 vmSymbols::void_method_signature(),
913 913 CHECK_NH);
914 914 }
915 915 Universe::set_system_thread_group(system_instance());
916 916
917 917 Handle main_instance = klass->allocate_instance_handle(CHECK_NH);
918 918 {
919 919 JavaValue result(T_VOID);
920 920 Handle string = java_lang_String::create_from_str("main", CHECK_NH);
921 921 JavaCalls::call_special(&result,
922 922 main_instance,
923 923 klass,
924 924 vmSymbols::object_initializer_name(),
925 925 vmSymbols::threadgroup_string_void_signature(),
926 926 system_instance,
927 927 string,
928 928 CHECK_NH);
929 929 }
930 930 return main_instance;
931 931 }
932 932
933 933 // Creates the initial Thread
934 934 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) {
935 935 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
936 936 instanceKlassHandle klass (THREAD, k);
937 937 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL);
938 938
939 939 java_lang_Thread::set_thread(thread_oop(), thread);
940 940 java_lang_Thread::set_priority(thread_oop(), NormPriority);
941 941 thread->set_threadObj(thread_oop());
942 942
943 943 Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
944 944
945 945 JavaValue result(T_VOID);
946 946 JavaCalls::call_special(&result, thread_oop,
947 947 klass,
948 948 vmSymbols::object_initializer_name(),
949 949 vmSymbols::threadgroup_string_void_signature(),
950 950 thread_group,
951 951 string,
952 952 CHECK_NULL);
953 953 return thread_oop();
954 954 }
955 955
956 956 static void call_initializeSystemClass(TRAPS) {
957 957 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
958 958 instanceKlassHandle klass (THREAD, k);
959 959
960 960 JavaValue result(T_VOID);
961 961 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(),
962 962 vmSymbols::void_method_signature(), CHECK);
963 963 }
964 964
965 965 // General purpose hook into Java code, run once when the VM is initialized.
966 966 // The Java library method itself may be changed independently from the VM.
967 967 static void call_postVMInitHook(TRAPS) {
968 968 klassOop k = SystemDictionary::sun_misc_PostVMInitHook_klass();
969 969 instanceKlassHandle klass (THREAD, k);
970 970 if (klass.not_null()) {
971 971 JavaValue result(T_VOID);
972 972 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
973 973 vmSymbols::void_method_signature(),
974 974 CHECK);
975 975 }
976 976 }
977 977
978 978 static void reset_vm_info_property(TRAPS) {
979 979 // the vm info string
980 980 ResourceMark rm(THREAD);
981 981 const char *vm_info = VM_Version::vm_info_string();
982 982
983 983 // java.lang.System class
984 984 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
985 985 instanceKlassHandle klass (THREAD, k);
986 986
987 987 // setProperty arguments
988 988 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK);
989 989 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK);
990 990
991 991 // return value
992 992 JavaValue r(T_OBJECT);
993 993
994 994 // public static String setProperty(String key, String value);
995 995 JavaCalls::call_static(&r,
996 996 klass,
997 997 vmSymbols::setProperty_name(),
998 998 vmSymbols::string_string_string_signature(),
999 999 key_str,
1000 1000 value_str,
1001 1001 CHECK);
1002 1002 }
1003 1003
1004 1004
1005 1005 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) {
1006 1006 assert(thread_group.not_null(), "thread group should be specified");
1007 1007 assert(threadObj() == NULL, "should only create Java thread object once");
1008 1008
1009 1009 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
1010 1010 instanceKlassHandle klass (THREAD, k);
1011 1011 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1012 1012
1013 1013 java_lang_Thread::set_thread(thread_oop(), this);
1014 1014 java_lang_Thread::set_priority(thread_oop(), NormPriority);
1015 1015 set_threadObj(thread_oop());
1016 1016
1017 1017 JavaValue result(T_VOID);
1018 1018 if (thread_name != NULL) {
1019 1019 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
1020 1020 // Thread gets assigned specified name and null target
1021 1021 JavaCalls::call_special(&result,
1022 1022 thread_oop,
1023 1023 klass,
1024 1024 vmSymbols::object_initializer_name(),
1025 1025 vmSymbols::threadgroup_string_void_signature(),
1026 1026 thread_group, // Argument 1
1027 1027 name, // Argument 2
1028 1028 THREAD);
1029 1029 } else {
1030 1030 // Thread gets assigned name "Thread-nnn" and null target
1031 1031 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
1032 1032 JavaCalls::call_special(&result,
1033 1033 thread_oop,
1034 1034 klass,
1035 1035 vmSymbols::object_initializer_name(),
1036 1036 vmSymbols::threadgroup_runnable_void_signature(),
1037 1037 thread_group, // Argument 1
1038 1038 Handle(), // Argument 2
1039 1039 THREAD);
1040 1040 }
1041 1041
1042 1042
1043 1043 if (daemon) {
1044 1044 java_lang_Thread::set_daemon(thread_oop());
1045 1045 }
1046 1046
1047 1047 if (HAS_PENDING_EXCEPTION) {
1048 1048 return;
1049 1049 }
1050 1050
1051 1051 KlassHandle group(this, SystemDictionary::ThreadGroup_klass());
1052 1052 Handle threadObj(this, this->threadObj());
1053 1053
1054 1054 JavaCalls::call_special(&result,
1055 1055 thread_group,
1056 1056 group,
1057 1057 vmSymbols::add_method_name(),
1058 1058 vmSymbols::thread_void_signature(),
1059 1059 threadObj, // Arg 1
1060 1060 THREAD);
1061 1061
1062 1062
1063 1063 }
1064 1064
1065 1065 // NamedThread -- non-JavaThread subclasses with multiple
1066 1066 // uniquely named instances should derive from this.
1067 1067 NamedThread::NamedThread() : Thread() {
1068 1068 _name = NULL;
1069 1069 _processed_thread = NULL;
1070 1070 }
1071 1071
1072 1072 NamedThread::~NamedThread() {
1073 1073 if (_name != NULL) {
1074 1074 FREE_C_HEAP_ARRAY(char, _name);
1075 1075 _name = NULL;
1076 1076 }
1077 1077 }
1078 1078
1079 1079 void NamedThread::set_name(const char* format, ...) {
1080 1080 guarantee(_name == NULL, "Only get to set name once.");
1081 1081 _name = NEW_C_HEAP_ARRAY(char, max_name_len);
1082 1082 guarantee(_name != NULL, "alloc failure");
1083 1083 va_list ap;
1084 1084 va_start(ap, format);
1085 1085 jio_vsnprintf(_name, max_name_len, format, ap);
1086 1086 va_end(ap);
1087 1087 }
1088 1088
1089 1089 // ======= WatcherThread ========
1090 1090
1091 1091 // The watcher thread exists to simulate timer interrupts. It should
1092 1092 // be replaced by an abstraction over whatever native support for
1093 1093 // timer interrupts exists on the platform.
1094 1094
1095 1095 WatcherThread* WatcherThread::_watcher_thread = NULL;
1096 1096 volatile bool WatcherThread::_should_terminate = false;
1097 1097
1098 1098 WatcherThread::WatcherThread() : Thread() {
1099 1099 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
1100 1100 if (os::create_thread(this, os::watcher_thread)) {
1101 1101 _watcher_thread = this;
1102 1102
1103 1103 // Set the watcher thread to the highest OS priority which should not be
1104 1104 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
1105 1105 // is created. The only normal thread using this priority is the reference
1106 1106 // handler thread, which runs for very short intervals only.
1107 1107 // If the VMThread's priority is not lower than the WatcherThread profiling
1108 1108 // will be inaccurate.
1109 1109 os::set_priority(this, MaxPriority);
1110 1110 if (!DisableStartThread) {
1111 1111 os::start_thread(this);
1112 1112 }
1113 1113 }
1114 1114 }
1115 1115
1116 1116 void WatcherThread::run() {
1117 1117 assert(this == watcher_thread(), "just checking");
1118 1118
1119 1119 this->record_stack_base_and_size();
1120 1120 this->initialize_thread_local_storage();
1121 1121 this->set_active_handles(JNIHandleBlock::allocate_block());
1122 1122 while(!_should_terminate) {
1123 1123 assert(watcher_thread() == Thread::current(), "thread consistency check");
1124 1124 assert(watcher_thread() == this, "thread consistency check");
1125 1125
1126 1126 // Calculate how long it'll be until the next PeriodicTask work
1127 1127 // should be done, and sleep that amount of time.
1128 1128 size_t time_to_wait = PeriodicTask::time_to_wait();
1129 1129
1130 1130 // we expect this to timeout - we only ever get unparked when
1131 1131 // we should terminate
1132 1132 {
1133 1133 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
1134 1134
1135 1135 jlong prev_time = os::javaTimeNanos();
1136 1136 for (;;) {
1137 1137 int res= _SleepEvent->park(time_to_wait);
1138 1138 if (res == OS_TIMEOUT || _should_terminate)
1139 1139 break;
1140 1140 // spurious wakeup of some kind
1141 1141 jlong now = os::javaTimeNanos();
1142 1142 time_to_wait -= (now - prev_time) / 1000000;
1143 1143 if (time_to_wait <= 0)
1144 1144 break;
1145 1145 prev_time = now;
1146 1146 }
1147 1147 }
1148 1148
1149 1149 if (is_error_reported()) {
1150 1150 // A fatal error has happened, the error handler(VMError::report_and_die)
1151 1151 // should abort JVM after creating an error log file. However in some
1152 1152 // rare cases, the error handler itself might deadlock. Here we try to
1153 1153 // kill JVM if the fatal error handler fails to abort in 2 minutes.
1154 1154 //
1155 1155 // This code is in WatcherThread because WatcherThread wakes up
1156 1156 // periodically so the fatal error handler doesn't need to do anything;
1157 1157 // also because the WatcherThread is less likely to crash than other
1158 1158 // threads.
1159 1159
1160 1160 for (;;) {
1161 1161 if (!ShowMessageBoxOnError
1162 1162 && (OnError == NULL || OnError[0] == '\0')
1163 1163 && Arguments::abort_hook() == NULL) {
1164 1164 os::sleep(this, 2 * 60 * 1000, false);
1165 1165 fdStream err(defaultStream::output_fd());
1166 1166 err.print_raw_cr("# [ timer expired, abort... ]");
1167 1167 // skip atexit/vm_exit/vm_abort hooks
1168 1168 os::die();
1169 1169 }
1170 1170
1171 1171 // Wake up 5 seconds later, the fatal handler may reset OnError or
1172 1172 // ShowMessageBoxOnError when it is ready to abort.
1173 1173 os::sleep(this, 5 * 1000, false);
1174 1174 }
1175 1175 }
1176 1176
1177 1177 PeriodicTask::real_time_tick(time_to_wait);
1178 1178
1179 1179 // If we have no more tasks left due to dynamic disenrollment,
1180 1180 // shut down the thread since we don't currently support dynamic enrollment
1181 1181 if (PeriodicTask::num_tasks() == 0) {
1182 1182 _should_terminate = true;
1183 1183 }
1184 1184 }
1185 1185
1186 1186 // Signal that it is terminated
1187 1187 {
1188 1188 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
1189 1189 _watcher_thread = NULL;
1190 1190 Terminator_lock->notify();
1191 1191 }
1192 1192
1193 1193 // Thread destructor usually does this..
1194 1194 ThreadLocalStorage::set_thread(NULL);
1195 1195 }
1196 1196
1197 1197 void WatcherThread::start() {
1198 1198 if (watcher_thread() == NULL) {
1199 1199 _should_terminate = false;
1200 1200 // Create the single instance of WatcherThread
1201 1201 new WatcherThread();
1202 1202 }
1203 1203 }
1204 1204
1205 1205 void WatcherThread::stop() {
1206 1206 // it is ok to take late safepoints here, if needed
1207 1207 MutexLocker mu(Terminator_lock);
1208 1208 _should_terminate = true;
1209 1209 OrderAccess::fence(); // ensure WatcherThread sees update in main loop
1210 1210
1211 1211 Thread* watcher = watcher_thread();
1212 1212 if (watcher != NULL)
1213 1213 watcher->_SleepEvent->unpark();
1214 1214
1215 1215 while(watcher_thread() != NULL) {
1216 1216 // This wait should make safepoint checks, wait without a timeout,
1217 1217 // and wait as a suspend-equivalent condition.
1218 1218 //
1219 1219 // Note: If the FlatProfiler is running, then this thread is waiting
1220 1220 // for the WatcherThread to terminate and the WatcherThread, via the
1221 1221 // FlatProfiler task, is waiting for the external suspend request on
1222 1222 // this thread to complete. wait_for_ext_suspend_completion() will
1223 1223 // eventually timeout, but that takes time. Making this wait a
1224 1224 // suspend-equivalent condition solves that timeout problem.
1225 1225 //
1226 1226 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
1227 1227 Mutex::_as_suspend_equivalent_flag);
1228 1228 }
1229 1229 }
1230 1230
1231 1231 void WatcherThread::print_on(outputStream* st) const {
1232 1232 st->print("\"%s\" ", name());
1233 1233 Thread::print_on(st);
1234 1234 st->cr();
1235 1235 }
1236 1236
1237 1237 // ======= JavaThread ========
1238 1238
1239 1239 // A JavaThread is a normal Java thread
1240 1240
1241 1241 void JavaThread::initialize() {
1242 1242 // Initialize fields
1243 1243
1244 1244 // Set the claimed par_id to -1 (ie not claiming any par_ids)
1245 1245 set_claimed_par_id(-1);
1246 1246
1247 1247 set_saved_exception_pc(NULL);
1248 1248 set_threadObj(NULL);
1249 1249 _anchor.clear();
1250 1250 set_entry_point(NULL);
1251 1251 set_jni_functions(jni_functions());
1252 1252 set_callee_target(NULL);
1253 1253 set_vm_result(NULL);
1254 1254 set_vm_result_2(NULL);
1255 1255 set_vframe_array_head(NULL);
1256 1256 set_vframe_array_last(NULL);
1257 1257 set_deferred_locals(NULL);
1258 1258 set_deopt_mark(NULL);
1259 1259 set_deopt_nmethod(NULL);
1260 1260 clear_must_deopt_id();
1261 1261 set_monitor_chunks(NULL);
1262 1262 set_next(NULL);
1263 1263 set_thread_state(_thread_new);
1264 1264 _terminated = _not_terminated;
1265 1265 _privileged_stack_top = NULL;
1266 1266 _array_for_gc = NULL;
1267 1267 _suspend_equivalent = false;
1268 1268 _in_deopt_handler = 0;
1269 1269 _doing_unsafe_access = false;
1270 1270 _stack_guard_state = stack_guard_unused;
1271 1271 _exception_oop = NULL;
1272 1272 _exception_pc = 0;
1273 1273 _exception_handler_pc = 0;
1274 1274 _exception_stack_size = 0;
1275 1275 _is_method_handle_return = 0;
1276 1276 _jvmti_thread_state= NULL;
1277 1277 _should_post_on_exceptions_flag = JNI_FALSE;
1278 1278 _jvmti_get_loaded_classes_closure = NULL;
1279 1279 _interp_only_mode = 0;
1280 1280 _special_runtime_exit_condition = _no_async_condition;
1281 1281 _pending_async_exception = NULL;
1282 1282 _is_compiling = false;
1283 1283 _thread_stat = NULL;
1284 1284 _thread_stat = new ThreadStatistics();
1285 1285 _blocked_on_compilation = false;
1286 1286 _jni_active_critical = 0;
1287 1287 _do_not_unlock_if_synchronized = false;
1288 1288 _cached_monitor_info = NULL;
1289 1289 _parker = Parker::Allocate(this) ;
1290 1290
1291 1291 #ifndef PRODUCT
1292 1292 _jmp_ring_index = 0;
1293 1293 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) {
1294 1294 record_jump(NULL, NULL, NULL, 0);
1295 1295 }
1296 1296 #endif /* PRODUCT */
1297 1297
1298 1298 set_thread_profiler(NULL);
1299 1299 if (FlatProfiler::is_active()) {
1300 1300 // This is where we would decide to either give each thread it's own profiler
1301 1301 // or use one global one from FlatProfiler,
1302 1302 // or up to some count of the number of profiled threads, etc.
1303 1303 ThreadProfiler* pp = new ThreadProfiler();
1304 1304 pp->engage();
1305 1305 set_thread_profiler(pp);
1306 1306 }
1307 1307
1308 1308 // Setup safepoint state info for this thread
1309 1309 ThreadSafepointState::create(this);
1310 1310
1311 1311 debug_only(_java_call_counter = 0);
1312 1312
1313 1313 // JVMTI PopFrame support
1314 1314 _popframe_condition = popframe_inactive;
1315 1315 _popframe_preserved_args = NULL;
1316 1316 _popframe_preserved_args_size = 0;
1317 1317
1318 1318 pd_initialize();
1319 1319 }
1320 1320
1321 1321 #ifndef SERIALGC
1322 1322 SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
1323 1323 DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
1324 1324 #endif // !SERIALGC
1325 1325
1326 1326 JavaThread::JavaThread(bool is_attaching) :
1327 1327 Thread()
1328 1328 #ifndef SERIALGC
1329 1329 , _satb_mark_queue(&_satb_mark_queue_set),
1330 1330 _dirty_card_queue(&_dirty_card_queue_set)
1331 1331 #endif // !SERIALGC
1332 1332 {
1333 1333 initialize();
1334 1334 _is_attaching = is_attaching;
1335 1335 assert(_deferred_card_mark.is_empty(), "Default MemRegion ctor");
1336 1336 }
1337 1337
1338 1338 bool JavaThread::reguard_stack(address cur_sp) {
1339 1339 if (_stack_guard_state != stack_guard_yellow_disabled) {
1340 1340 return true; // Stack already guarded or guard pages not needed.
1341 1341 }
1342 1342
1343 1343 if (register_stack_overflow()) {
1344 1344 // For those architectures which have separate register and
1345 1345 // memory stacks, we must check the register stack to see if
1346 1346 // it has overflowed.
1347 1347 return false;
1348 1348 }
1349 1349
1350 1350 // Java code never executes within the yellow zone: the latter is only
1351 1351 // there to provoke an exception during stack banging. If java code
1352 1352 // is executing there, either StackShadowPages should be larger, or
1353 1353 // some exception code in c1, c2 or the interpreter isn't unwinding
1354 1354 // when it should.
1355 1355 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages");
1356 1356
1357 1357 enable_stack_yellow_zone();
1358 1358 return true;
1359 1359 }
1360 1360
1361 1361 bool JavaThread::reguard_stack(void) {
1362 1362 return reguard_stack(os::current_stack_pointer());
1363 1363 }
1364 1364
1365 1365
1366 1366 void JavaThread::block_if_vm_exited() {
1367 1367 if (_terminated == _vm_exited) {
1368 1368 // _vm_exited is set at safepoint, and Threads_lock is never released
1369 1369 // we will block here forever
1370 1370 Threads_lock->lock_without_safepoint_check();
1371 1371 ShouldNotReachHere();
1372 1372 }
1373 1373 }
1374 1374
1375 1375
1376 1376 // Remove this ifdef when C1 is ported to the compiler interface.
1377 1377 static void compiler_thread_entry(JavaThread* thread, TRAPS);
1378 1378
1379 1379 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
1380 1380 Thread()
1381 1381 #ifndef SERIALGC
1382 1382 , _satb_mark_queue(&_satb_mark_queue_set),
1383 1383 _dirty_card_queue(&_dirty_card_queue_set)
1384 1384 #endif // !SERIALGC
1385 1385 {
1386 1386 if (TraceThreadEvents) {
1387 1387 tty->print_cr("creating thread %p", this);
1388 1388 }
1389 1389 initialize();
1390 1390 _is_attaching = false;
1391 1391 set_entry_point(entry_point);
1392 1392 // Create the native thread itself.
1393 1393 // %note runtime_23
1394 1394 os::ThreadType thr_type = os::java_thread;
1395 1395 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
1396 1396 os::java_thread;
1397 1397 os::create_thread(this, thr_type, stack_sz);
1398 1398
1399 1399 // The _osthread may be NULL here because we ran out of memory (too many threads active).
1400 1400 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
1401 1401 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
1402 1402 // the exception consists of creating the exception object & initializing it, initialization
1403 1403 // will leave the VM via a JavaCall and then all locks must be unlocked).
1404 1404 //
1405 1405 // The thread is still suspended when we reach here. Thread must be explicit started
1406 1406 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
1407 1407 // by calling Threads:add. The reason why this is not done here, is because the thread
1408 1408 // object must be fully initialized (take a look at JVM_Start)
1409 1409 }
1410 1410
1411 1411 JavaThread::~JavaThread() {
1412 1412 if (TraceThreadEvents) {
1413 1413 tty->print_cr("terminate thread %p", this);
1414 1414 }
1415 1415
1416 1416 // JSR166 -- return the parker to the free list
1417 1417 Parker::Release(_parker);
1418 1418 _parker = NULL ;
1419 1419
1420 1420 // Free any remaining previous UnrollBlock
1421 1421 vframeArray* old_array = vframe_array_last();
1422 1422
1423 1423 if (old_array != NULL) {
1424 1424 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
1425 1425 old_array->set_unroll_block(NULL);
1426 1426 delete old_info;
1427 1427 delete old_array;
1428 1428 }
1429 1429
1430 1430 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
1431 1431 if (deferred != NULL) {
1432 1432 // This can only happen if thread is destroyed before deoptimization occurs.
1433 1433 assert(deferred->length() != 0, "empty array!");
1434 1434 do {
1435 1435 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
1436 1436 deferred->remove_at(0);
1437 1437 // individual jvmtiDeferredLocalVariableSet are CHeapObj's
1438 1438 delete dlv;
1439 1439 } while (deferred->length() != 0);
1440 1440 delete deferred;
1441 1441 }
1442 1442
1443 1443 // All Java related clean up happens in exit
1444 1444 ThreadSafepointState::destroy(this);
1445 1445 if (_thread_profiler != NULL) delete _thread_profiler;
1446 1446 if (_thread_stat != NULL) delete _thread_stat;
1447 1447 }
1448 1448
1449 1449
1450 1450 // The first routine called by a new Java thread
1451 1451 void JavaThread::run() {
1452 1452 // initialize thread-local alloc buffer related fields
1453 1453 this->initialize_tlab();
1454 1454
1455 1455 // used to test validitity of stack trace backs
1456 1456 this->record_base_of_stack_pointer();
1457 1457
1458 1458 // Record real stack base and size.
1459 1459 this->record_stack_base_and_size();
1460 1460
1461 1461 // Initialize thread local storage; set before calling MutexLocker
1462 1462 this->initialize_thread_local_storage();
1463 1463
1464 1464 this->create_stack_guard_pages();
1465 1465
1466 1466 this->cache_global_variables();
1467 1467
1468 1468 // Thread is now sufficient initialized to be handled by the safepoint code as being
1469 1469 // in the VM. Change thread state from _thread_new to _thread_in_vm
1470 1470 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
1471 1471
1472 1472 assert(JavaThread::current() == this, "sanity check");
1473 1473 assert(!Thread::current()->owns_locks(), "sanity check");
1474 1474
1475 1475 DTRACE_THREAD_PROBE(start, this);
1476 1476
1477 1477 // This operation might block. We call that after all safepoint checks for a new thread has
1478 1478 // been completed.
1479 1479 this->set_active_handles(JNIHandleBlock::allocate_block());
1480 1480
1481 1481 if (JvmtiExport::should_post_thread_life()) {
1482 1482 JvmtiExport::post_thread_start(this);
1483 1483 }
1484 1484
1485 1485 // We call another function to do the rest so we are sure that the stack addresses used
1486 1486 // from there will be lower than the stack base just computed
1487 1487 thread_main_inner();
1488 1488
1489 1489 // Note, thread is no longer valid at this point!
1490 1490 }
1491 1491
1492 1492
1493 1493 void JavaThread::thread_main_inner() {
1494 1494 assert(JavaThread::current() == this, "sanity check");
1495 1495 assert(this->threadObj() != NULL, "just checking");
1496 1496
1497 1497 // Execute thread entry point unless this thread has a pending exception
1498 1498 // or has been stopped before starting.
1499 1499 // Note: Due to JVM_StopThread we can have pending exceptions already!
1500 1500 if (!this->has_pending_exception() &&
1501 1501 !java_lang_Thread::is_stillborn(this->threadObj())) {
1502 1502 HandleMark hm(this);
1503 1503 this->entry_point()(this, this);
1504 1504 }
1505 1505
1506 1506 DTRACE_THREAD_PROBE(stop, this);
1507 1507
1508 1508 this->exit(false);
1509 1509 delete this;
1510 1510 }
1511 1511
1512 1512
1513 1513 static void ensure_join(JavaThread* thread) {
1514 1514 // We do not need to grap the Threads_lock, since we are operating on ourself.
1515 1515 Handle threadObj(thread, thread->threadObj());
1516 1516 assert(threadObj.not_null(), "java thread object must exist");
1517 1517 ObjectLocker lock(threadObj, thread);
1518 1518 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1519 1519 thread->clear_pending_exception();
1520 1520 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
1521 1521 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
1522 1522 // Clear the native thread instance - this makes isAlive return false and allows the join()
1523 1523 // to complete once we've done the notify_all below
1524 1524 java_lang_Thread::set_thread(threadObj(), NULL);
1525 1525 lock.notify_all(thread);
1526 1526 // Ignore pending exception (ThreadDeath), since we are exiting anyway
1527 1527 thread->clear_pending_exception();
1528 1528 }
1529 1529
1530 1530
1531 1531 // For any new cleanup additions, please check to see if they need to be applied to
1532 1532 // cleanup_failed_attach_current_thread as well.
1533 1533 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
1534 1534 assert(this == JavaThread::current(), "thread consistency check");
1535 1535 if (!InitializeJavaLangSystem) return;
1536 1536
1537 1537 HandleMark hm(this);
1538 1538 Handle uncaught_exception(this, this->pending_exception());
1539 1539 this->clear_pending_exception();
1540 1540 Handle threadObj(this, this->threadObj());
1541 1541 assert(threadObj.not_null(), "Java thread object should be created");
1542 1542
1543 1543 if (get_thread_profiler() != NULL) {
1544 1544 get_thread_profiler()->disengage();
1545 1545 ResourceMark rm;
1546 1546 get_thread_profiler()->print(get_thread_name());
1547 1547 }
1548 1548
1549 1549
1550 1550 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
1551 1551 {
1552 1552 EXCEPTION_MARK;
1553 1553
1554 1554 CLEAR_PENDING_EXCEPTION;
1555 1555 }
1556 1556 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This
1557 1557 // has to be fixed by a runtime query method
1558 1558 if (!destroy_vm || JDK_Version::is_jdk12x_version()) {
1559 1559 // JSR-166: change call from from ThreadGroup.uncaughtException to
1560 1560 // java.lang.Thread.dispatchUncaughtException
1561 1561 if (uncaught_exception.not_null()) {
1562 1562 Handle group(this, java_lang_Thread::threadGroup(threadObj()));
1563 1563 Events::log("uncaught exception INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT",
1564 1564 (address)uncaught_exception(), (address)threadObj(), (address)group());
1565 1565 {
1566 1566 EXCEPTION_MARK;
1567 1567 // Check if the method Thread.dispatchUncaughtException() exists. If so
1568 1568 // call it. Otherwise we have an older library without the JSR-166 changes,
1569 1569 // so call ThreadGroup.uncaughtException()
1570 1570 KlassHandle recvrKlass(THREAD, threadObj->klass());
1571 1571 CallInfo callinfo;
1572 1572 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1573 1573 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass,
1574 1574 vmSymbols::dispatchUncaughtException_name(),
1575 1575 vmSymbols::throwable_void_signature(),
1576 1576 KlassHandle(), false, false, THREAD);
1577 1577 CLEAR_PENDING_EXCEPTION;
1578 1578 methodHandle method = callinfo.selected_method();
1579 1579 if (method.not_null()) {
1580 1580 JavaValue result(T_VOID);
1581 1581 JavaCalls::call_virtual(&result,
1582 1582 threadObj, thread_klass,
1583 1583 vmSymbols::dispatchUncaughtException_name(),
1584 1584 vmSymbols::throwable_void_signature(),
1585 1585 uncaught_exception,
1586 1586 THREAD);
1587 1587 } else {
1588 1588 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass());
1589 1589 JavaValue result(T_VOID);
1590 1590 JavaCalls::call_virtual(&result,
1591 1591 group, thread_group,
1592 1592 vmSymbols::uncaughtException_name(),
1593 1593 vmSymbols::thread_throwable_void_signature(),
1594 1594 threadObj, // Arg 1
1595 1595 uncaught_exception, // Arg 2
1596 1596 THREAD);
1597 1597 }
1598 1598 if (HAS_PENDING_EXCEPTION) {
1599 1599 ResourceMark rm(this);
1600 1600 jio_fprintf(defaultStream::error_stream(),
1601 1601 "\nException: %s thrown from the UncaughtExceptionHandler"
1602 1602 " in thread \"%s\"\n",
1603 1603 Klass::cast(pending_exception()->klass())->external_name(),
1604 1604 get_thread_name());
1605 1605 CLEAR_PENDING_EXCEPTION;
1606 1606 }
1607 1607 }
1608 1608 }
1609 1609
1610 1610 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during
1611 1611 // the execution of the method. If that is not enough, then we don't really care. Thread.stop
1612 1612 // is deprecated anyhow.
1613 1613 { int count = 3;
1614 1614 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
1615 1615 EXCEPTION_MARK;
1616 1616 JavaValue result(T_VOID);
1617 1617 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass());
1618 1618 JavaCalls::call_virtual(&result,
1619 1619 threadObj, thread_klass,
1620 1620 vmSymbols::exit_method_name(),
1621 1621 vmSymbols::void_method_signature(),
1622 1622 THREAD);
1623 1623 CLEAR_PENDING_EXCEPTION;
1624 1624 }
1625 1625 }
1626 1626
1627 1627 // notify JVMTI
1628 1628 if (JvmtiExport::should_post_thread_life()) {
1629 1629 JvmtiExport::post_thread_end(this);
1630 1630 }
1631 1631
1632 1632 // We have notified the agents that we are exiting, before we go on,
1633 1633 // we must check for a pending external suspend request and honor it
1634 1634 // in order to not surprise the thread that made the suspend request.
1635 1635 while (true) {
1636 1636 {
1637 1637 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1638 1638 if (!is_external_suspend()) {
1639 1639 set_terminated(_thread_exiting);
1640 1640 ThreadService::current_thread_exiting(this);
1641 1641 break;
1642 1642 }
1643 1643 // Implied else:
1644 1644 // Things get a little tricky here. We have a pending external
1645 1645 // suspend request, but we are holding the SR_lock so we
1646 1646 // can't just self-suspend. So we temporarily drop the lock
1647 1647 // and then self-suspend.
1648 1648 }
1649 1649
1650 1650 ThreadBlockInVM tbivm(this);
1651 1651 java_suspend_self();
1652 1652
1653 1653 // We're done with this suspend request, but we have to loop around
1654 1654 // and check again. Eventually we will get SR_lock without a pending
1655 1655 // external suspend request and will be able to mark ourselves as
1656 1656 // exiting.
1657 1657 }
1658 1658 // no more external suspends are allowed at this point
1659 1659 } else {
1660 1660 // before_exit() has already posted JVMTI THREAD_END events
1661 1661 }
1662 1662
1663 1663 // Notify waiters on thread object. This has to be done after exit() is called
1664 1664 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
1665 1665 // group should have the destroyed bit set before waiters are notified).
1666 1666 ensure_join(this);
1667 1667 assert(!this->has_pending_exception(), "ensure_join should have cleared");
1668 1668
1669 1669 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
1670 1670 // held by this thread must be released. A detach operation must only
1671 1671 // get here if there are no Java frames on the stack. Therefore, any
1672 1672 // owned monitors at this point MUST be JNI-acquired monitors which are
1673 1673 // pre-inflated and in the monitor cache.
1674 1674 //
1675 1675 // ensure_join() ignores IllegalThreadStateExceptions, and so does this.
1676 1676 if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
1677 1677 assert(!this->has_last_Java_frame(), "detaching with Java frames?");
1678 1678 ObjectSynchronizer::release_monitors_owned_by_thread(this);
1679 1679 assert(!this->has_pending_exception(), "release_monitors should have cleared");
1680 1680 }
1681 1681
1682 1682 // These things needs to be done while we are still a Java Thread. Make sure that thread
1683 1683 // is in a consistent state, in case GC happens
1684 1684 assert(_privileged_stack_top == NULL, "must be NULL when we get here");
1685 1685
1686 1686 if (active_handles() != NULL) {
1687 1687 JNIHandleBlock* block = active_handles();
1688 1688 set_active_handles(NULL);
1689 1689 JNIHandleBlock::release_block(block);
1690 1690 }
1691 1691
1692 1692 if (free_handle_block() != NULL) {
1693 1693 JNIHandleBlock* block = free_handle_block();
1694 1694 set_free_handle_block(NULL);
1695 1695 JNIHandleBlock::release_block(block);
1696 1696 }
1697 1697
1698 1698 // These have to be removed while this is still a valid thread.
1699 1699 remove_stack_guard_pages();
1700 1700
1701 1701 if (UseTLAB) {
1702 1702 tlab().make_parsable(true); // retire TLAB
1703 1703 }
1704 1704
1705 1705 if (JvmtiEnv::environments_might_exist()) {
1706 1706 JvmtiExport::cleanup_thread(this);
1707 1707 }
1708 1708
1709 1709 #ifndef SERIALGC
1710 1710 // We must flush G1-related buffers before removing a thread from
1711 1711 // the list of active threads.
1712 1712 if (UseG1GC) {
1713 1713 flush_barrier_queues();
1714 1714 }
1715 1715 #endif
1716 1716
1717 1717 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
1718 1718 Threads::remove(this);
1719 1719 }
1720 1720
1721 1721 #ifndef SERIALGC
1722 1722 // Flush G1-related queues.
1723 1723 void JavaThread::flush_barrier_queues() {
1724 1724 satb_mark_queue().flush();
1725 1725 dirty_card_queue().flush();
1726 1726 }
1727 1727
1728 1728 void JavaThread::initialize_queues() {
1729 1729 assert(!SafepointSynchronize::is_at_safepoint(),
1730 1730 "we should not be at a safepoint");
1731 1731
1732 1732 ObjPtrQueue& satb_queue = satb_mark_queue();
1733 1733 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
1734 1734 // The SATB queue should have been constructed with its active
1735 1735 // field set to false.
1736 1736 assert(!satb_queue.is_active(), "SATB queue should not be active");
1737 1737 assert(satb_queue.is_empty(), "SATB queue should be empty");
1738 1738 // If we are creating the thread during a marking cycle, we should
1739 1739 // set the active field of the SATB queue to true.
1740 1740 if (satb_queue_set.is_active()) {
1741 1741 satb_queue.set_active(true);
1742 1742 }
1743 1743
1744 1744 DirtyCardQueue& dirty_queue = dirty_card_queue();
1745 1745 // The dirty card queue should have been constructed with its
1746 1746 // active field set to true.
1747 1747 assert(dirty_queue.is_active(), "dirty card queue should be active");
1748 1748 }
1749 1749 #endif // !SERIALGC
1750 1750
1751 1751 void JavaThread::cleanup_failed_attach_current_thread() {
1752 1752 if (get_thread_profiler() != NULL) {
1753 1753 get_thread_profiler()->disengage();
1754 1754 ResourceMark rm;
1755 1755 get_thread_profiler()->print(get_thread_name());
1756 1756 }
1757 1757
1758 1758 if (active_handles() != NULL) {
1759 1759 JNIHandleBlock* block = active_handles();
1760 1760 set_active_handles(NULL);
1761 1761 JNIHandleBlock::release_block(block);
1762 1762 }
1763 1763
1764 1764 if (free_handle_block() != NULL) {
1765 1765 JNIHandleBlock* block = free_handle_block();
1766 1766 set_free_handle_block(NULL);
1767 1767 JNIHandleBlock::release_block(block);
1768 1768 }
1769 1769
1770 1770 // These have to be removed while this is still a valid thread.
1771 1771 remove_stack_guard_pages();
1772 1772
1773 1773 if (UseTLAB) {
1774 1774 tlab().make_parsable(true); // retire TLAB, if any
1775 1775 }
1776 1776
1777 1777 #ifndef SERIALGC
1778 1778 if (UseG1GC) {
1779 1779 flush_barrier_queues();
1780 1780 }
1781 1781 #endif
1782 1782
1783 1783 Threads::remove(this);
1784 1784 delete this;
1785 1785 }
1786 1786
1787 1787
1788 1788
1789 1789
1790 1790 JavaThread* JavaThread::active() {
1791 1791 Thread* thread = ThreadLocalStorage::thread();
1792 1792 assert(thread != NULL, "just checking");
1793 1793 if (thread->is_Java_thread()) {
1794 1794 return (JavaThread*) thread;
1795 1795 } else {
1796 1796 assert(thread->is_VM_thread(), "this must be a vm thread");
1797 1797 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1798 1798 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
1799 1799 assert(ret->is_Java_thread(), "must be a Java thread");
1800 1800 return ret;
1801 1801 }
1802 1802 }
1803 1803
1804 1804 bool JavaThread::is_lock_owned(address adr) const {
1805 1805 if (Thread::is_lock_owned(adr)) return true;
1806 1806
1807 1807 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
1808 1808 if (chunk->contains(adr)) return true;
1809 1809 }
1810 1810
1811 1811 return false;
1812 1812 }
1813 1813
1814 1814
1815 1815 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1816 1816 chunk->set_next(monitor_chunks());
1817 1817 set_monitor_chunks(chunk);
1818 1818 }
1819 1819
1820 1820 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1821 1821 guarantee(monitor_chunks() != NULL, "must be non empty");
1822 1822 if (monitor_chunks() == chunk) {
1823 1823 set_monitor_chunks(chunk->next());
1824 1824 } else {
1825 1825 MonitorChunk* prev = monitor_chunks();
1826 1826 while (prev->next() != chunk) prev = prev->next();
1827 1827 prev->set_next(chunk->next());
1828 1828 }
1829 1829 }
1830 1830
1831 1831 // JVM support.
1832 1832
1833 1833 // Note: this function shouldn't block if it's called in
1834 1834 // _thread_in_native_trans state (such as from
1835 1835 // check_special_condition_for_native_trans()).
1836 1836 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
1837 1837
1838 1838 if (has_last_Java_frame() && has_async_condition()) {
1839 1839 // If we are at a polling page safepoint (not a poll return)
1840 1840 // then we must defer async exception because live registers
1841 1841 // will be clobbered by the exception path. Poll return is
1842 1842 // ok because the call we a returning from already collides
1843 1843 // with exception handling registers and so there is no issue.
1844 1844 // (The exception handling path kills call result registers but
1845 1845 // this is ok since the exception kills the result anyway).
1846 1846
1847 1847 if (is_at_poll_safepoint()) {
1848 1848 // if the code we are returning to has deoptimized we must defer
1849 1849 // the exception otherwise live registers get clobbered on the
1850 1850 // exception path before deoptimization is able to retrieve them.
1851 1851 //
1852 1852 RegisterMap map(this, false);
1853 1853 frame caller_fr = last_frame().sender(&map);
1854 1854 assert(caller_fr.is_compiled_frame(), "what?");
1855 1855 if (caller_fr.is_deoptimized_frame()) {
1856 1856 if (TraceExceptions) {
1857 1857 ResourceMark rm;
1858 1858 tty->print_cr("deferred async exception at compiled safepoint");
1859 1859 }
1860 1860 return;
1861 1861 }
1862 1862 }
1863 1863 }
1864 1864
1865 1865 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
1866 1866 if (condition == _no_async_condition) {
1867 1867 // Conditions have changed since has_special_runtime_exit_condition()
1868 1868 // was called:
1869 1869 // - if we were here only because of an external suspend request,
1870 1870 // then that was taken care of above (or cancelled) so we are done
1871 1871 // - if we were here because of another async request, then it has
1872 1872 // been cleared between the has_special_runtime_exit_condition()
1873 1873 // and now so again we are done
1874 1874 return;
1875 1875 }
1876 1876
1877 1877 // Check for pending async. exception
1878 1878 if (_pending_async_exception != NULL) {
1879 1879 // Only overwrite an already pending exception, if it is not a threadDeath.
1880 1880 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
1881 1881
1882 1882 // We cannot call Exceptions::_throw(...) here because we cannot block
1883 1883 set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
1884 1884
1885 1885 if (TraceExceptions) {
1886 1886 ResourceMark rm;
1887 1887 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this);
1888 1888 if (has_last_Java_frame() ) {
1889 1889 frame f = last_frame();
1890 1890 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp());
1891 1891 }
1892 1892 tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
1893 1893 }
1894 1894 _pending_async_exception = NULL;
1895 1895 clear_has_async_exception();
1896 1896 }
1897 1897 }
1898 1898
1899 1899 if (check_unsafe_error &&
1900 1900 condition == _async_unsafe_access_error && !has_pending_exception()) {
1901 1901 condition = _no_async_condition; // done
1902 1902 switch (thread_state()) {
1903 1903 case _thread_in_vm:
1904 1904 {
1905 1905 JavaThread* THREAD = this;
1906 1906 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1907 1907 }
1908 1908 case _thread_in_native:
1909 1909 {
1910 1910 ThreadInVMfromNative tiv(this);
1911 1911 JavaThread* THREAD = this;
1912 1912 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
1913 1913 }
1914 1914 case _thread_in_Java:
1915 1915 {
1916 1916 ThreadInVMfromJava tiv(this);
1917 1917 JavaThread* THREAD = this;
1918 1918 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
1919 1919 }
1920 1920 default:
1921 1921 ShouldNotReachHere();
1922 1922 }
1923 1923 }
1924 1924
1925 1925 assert(condition == _no_async_condition || has_pending_exception() ||
1926 1926 (!check_unsafe_error && condition == _async_unsafe_access_error),
1927 1927 "must have handled the async condition, if no exception");
1928 1928 }
1929 1929
1930 1930 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
1931 1931 //
1932 1932 // Check for pending external suspend. Internal suspend requests do
1933 1933 // not use handle_special_runtime_exit_condition().
1934 1934 // If JNIEnv proxies are allowed, don't self-suspend if the target
1935 1935 // thread is not the current thread. In older versions of jdbx, jdbx
1936 1936 // threads could call into the VM with another thread's JNIEnv so we
1937 1937 // can be here operating on behalf of a suspended thread (4432884).
1938 1938 bool do_self_suspend = is_external_suspend_with_lock();
1939 1939 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
1940 1940 //
1941 1941 // Because thread is external suspended the safepoint code will count
1942 1942 // thread as at a safepoint. This can be odd because we can be here
1943 1943 // as _thread_in_Java which would normally transition to _thread_blocked
1944 1944 // at a safepoint. We would like to mark the thread as _thread_blocked
1945 1945 // before calling java_suspend_self like all other callers of it but
1946 1946 // we must then observe proper safepoint protocol. (We can't leave
1947 1947 // _thread_blocked with a safepoint in progress). However we can be
1948 1948 // here as _thread_in_native_trans so we can't use a normal transition
1949 1949 // constructor/destructor pair because they assert on that type of
1950 1950 // transition. We could do something like:
1951 1951 //
1952 1952 // JavaThreadState state = thread_state();
1953 1953 // set_thread_state(_thread_in_vm);
1954 1954 // {
1955 1955 // ThreadBlockInVM tbivm(this);
1956 1956 // java_suspend_self()
1957 1957 // }
1958 1958 // set_thread_state(_thread_in_vm_trans);
1959 1959 // if (safepoint) block;
1960 1960 // set_thread_state(state);
1961 1961 //
1962 1962 // but that is pretty messy. Instead we just go with the way the
1963 1963 // code has worked before and note that this is the only path to
1964 1964 // java_suspend_self that doesn't put the thread in _thread_blocked
1965 1965 // mode.
1966 1966
1967 1967 frame_anchor()->make_walkable(this);
1968 1968 java_suspend_self();
1969 1969
1970 1970 // We might be here for reasons in addition to the self-suspend request
1971 1971 // so check for other async requests.
1972 1972 }
1973 1973
1974 1974 if (check_asyncs) {
1975 1975 check_and_handle_async_exceptions();
1976 1976 }
1977 1977 }
1978 1978
1979 1979 void JavaThread::send_thread_stop(oop java_throwable) {
1980 1980 assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
1981 1981 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
1982 1982 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
1983 1983
1984 1984 // Do not throw asynchronous exceptions against the compiler thread
1985 1985 // (the compiler thread should not be a Java thread -- fix in 1.4.2)
1986 1986 if (is_Compiler_thread()) return;
1987 1987
1988 1988 {
1989 1989 // Actually throw the Throwable against the target Thread - however
1990 1990 // only if there is no thread death exception installed already.
1991 1991 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
1992 1992 // If the topmost frame is a runtime stub, then we are calling into
1993 1993 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1994 1994 // must deoptimize the caller before continuing, as the compiled exception handler table
1995 1995 // may not be valid
1996 1996 if (has_last_Java_frame()) {
1997 1997 frame f = last_frame();
1998 1998 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
1999 1999 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2000 2000 RegisterMap reg_map(this, UseBiasedLocking);
2001 2001 frame compiled_frame = f.sender(®_map);
2002 2002 if (compiled_frame.can_be_deoptimized()) {
2003 2003 Deoptimization::deoptimize(this, compiled_frame, ®_map);
2004 2004 }
2005 2005 }
2006 2006 }
2007 2007
2008 2008 // Set async. pending exception in thread.
2009 2009 set_pending_async_exception(java_throwable);
2010 2010
2011 2011 if (TraceExceptions) {
2012 2012 ResourceMark rm;
2013 2013 tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name());
2014 2014 }
2015 2015 // for AbortVMOnException flag
2016 2016 NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name()));
2017 2017 }
2018 2018 }
2019 2019
2020 2020
2021 2021 // Interrupt thread so it will wake up from a potential wait()
2022 2022 Thread::interrupt(this);
2023 2023 }
2024 2024
2025 2025 // External suspension mechanism.
2026 2026 //
2027 2027 // Tell the VM to suspend a thread when ever it knows that it does not hold on
2028 2028 // to any VM_locks and it is at a transition
2029 2029 // Self-suspension will happen on the transition out of the vm.
2030 2030 // Catch "this" coming in from JNIEnv pointers when the thread has been freed
2031 2031 //
2032 2032 // Guarantees on return:
2033 2033 // + Target thread will not execute any new bytecode (that's why we need to
2034 2034 // force a safepoint)
2035 2035 // + Target thread will not enter any new monitors
2036 2036 //
2037 2037 void JavaThread::java_suspend() {
2038 2038 { MutexLocker mu(Threads_lock);
2039 2039 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
2040 2040 return;
2041 2041 }
2042 2042 }
2043 2043
2044 2044 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2045 2045 if (!is_external_suspend()) {
2046 2046 // a racing resume has cancelled us; bail out now
2047 2047 return;
2048 2048 }
2049 2049
2050 2050 // suspend is done
2051 2051 uint32_t debug_bits = 0;
2052 2052 // Warning: is_ext_suspend_completed() may temporarily drop the
2053 2053 // SR_lock to allow the thread to reach a stable thread state if
2054 2054 // it is currently in a transient thread state.
2055 2055 if (is_ext_suspend_completed(false /* !called_by_wait */,
2056 2056 SuspendRetryDelay, &debug_bits) ) {
2057 2057 return;
2058 2058 }
2059 2059 }
2060 2060
2061 2061 VM_ForceSafepoint vm_suspend;
2062 2062 VMThread::execute(&vm_suspend);
2063 2063 }
2064 2064
2065 2065 // Part II of external suspension.
2066 2066 // A JavaThread self suspends when it detects a pending external suspend
2067 2067 // request. This is usually on transitions. It is also done in places
2068 2068 // where continuing to the next transition would surprise the caller,
2069 2069 // e.g., monitor entry.
2070 2070 //
2071 2071 // Returns the number of times that the thread self-suspended.
2072 2072 //
2073 2073 // Note: DO NOT call java_suspend_self() when you just want to block current
2074 2074 // thread. java_suspend_self() is the second stage of cooperative
2075 2075 // suspension for external suspend requests and should only be used
2076 2076 // to complete an external suspend request.
2077 2077 //
2078 2078 int JavaThread::java_suspend_self() {
2079 2079 int ret = 0;
2080 2080
2081 2081 // we are in the process of exiting so don't suspend
2082 2082 if (is_exiting()) {
2083 2083 clear_external_suspend();
2084 2084 return ret;
2085 2085 }
2086 2086
2087 2087 assert(_anchor.walkable() ||
2088 2088 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
2089 2089 "must have walkable stack");
2090 2090
2091 2091 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2092 2092
2093 2093 assert(!this->is_ext_suspended(),
2094 2094 "a thread trying to self-suspend should not already be suspended");
2095 2095
2096 2096 if (this->is_suspend_equivalent()) {
2097 2097 // If we are self-suspending as a result of the lifting of a
2098 2098 // suspend equivalent condition, then the suspend_equivalent
2099 2099 // flag is not cleared until we set the ext_suspended flag so
2100 2100 // that wait_for_ext_suspend_completion() returns consistent
2101 2101 // results.
2102 2102 this->clear_suspend_equivalent();
2103 2103 }
2104 2104
2105 2105 // A racing resume may have cancelled us before we grabbed SR_lock
2106 2106 // above. Or another external suspend request could be waiting for us
2107 2107 // by the time we return from SR_lock()->wait(). The thread
2108 2108 // that requested the suspension may already be trying to walk our
2109 2109 // stack and if we return now, we can change the stack out from under
2110 2110 // it. This would be a "bad thing (TM)" and cause the stack walker
2111 2111 // to crash. We stay self-suspended until there are no more pending
2112 2112 // external suspend requests.
2113 2113 while (is_external_suspend()) {
2114 2114 ret++;
2115 2115 this->set_ext_suspended();
2116 2116
2117 2117 // _ext_suspended flag is cleared by java_resume()
2118 2118 while (is_ext_suspended()) {
2119 2119 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
2120 2120 }
2121 2121 }
2122 2122
2123 2123 return ret;
2124 2124 }
2125 2125
2126 2126 #ifdef ASSERT
2127 2127 // verify the JavaThread has not yet been published in the Threads::list, and
2128 2128 // hence doesn't need protection from concurrent access at this stage
2129 2129 void JavaThread::verify_not_published() {
2130 2130 if (!Threads_lock->owned_by_self()) {
2131 2131 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag);
2132 2132 assert( !Threads::includes(this),
2133 2133 "java thread shouldn't have been published yet!");
2134 2134 }
2135 2135 else {
2136 2136 assert( !Threads::includes(this),
2137 2137 "java thread shouldn't have been published yet!");
2138 2138 }
2139 2139 }
2140 2140 #endif
2141 2141
2142 2142 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2143 2143 // progress or when _suspend_flags is non-zero.
2144 2144 // Current thread needs to self-suspend if there is a suspend request and/or
2145 2145 // block if a safepoint is in progress.
2146 2146 // Async exception ISN'T checked.
2147 2147 // Note only the ThreadInVMfromNative transition can call this function
2148 2148 // directly and when thread state is _thread_in_native_trans
2149 2149 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
2150 2150 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
2151 2151
2152 2152 JavaThread *curJT = JavaThread::current();
2153 2153 bool do_self_suspend = thread->is_external_suspend();
2154 2154
2155 2155 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
2156 2156
2157 2157 // If JNIEnv proxies are allowed, don't self-suspend if the target
2158 2158 // thread is not the current thread. In older versions of jdbx, jdbx
2159 2159 // threads could call into the VM with another thread's JNIEnv so we
2160 2160 // can be here operating on behalf of a suspended thread (4432884).
2161 2161 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
2162 2162 JavaThreadState state = thread->thread_state();
2163 2163
2164 2164 // We mark this thread_blocked state as a suspend-equivalent so
2165 2165 // that a caller to is_ext_suspend_completed() won't be confused.
2166 2166 // The suspend-equivalent state is cleared by java_suspend_self().
2167 2167 thread->set_suspend_equivalent();
2168 2168
2169 2169 // If the safepoint code sees the _thread_in_native_trans state, it will
2170 2170 // wait until the thread changes to other thread state. There is no
2171 2171 // guarantee on how soon we can obtain the SR_lock and complete the
2172 2172 // self-suspend request. It would be a bad idea to let safepoint wait for
2173 2173 // too long. Temporarily change the state to _thread_blocked to
2174 2174 // let the VM thread know that this thread is ready for GC. The problem
2175 2175 // of changing thread state is that safepoint could happen just after
2176 2176 // java_suspend_self() returns after being resumed, and VM thread will
2177 2177 // see the _thread_blocked state. We must check for safepoint
2178 2178 // after restoring the state and make sure we won't leave while a safepoint
2179 2179 // is in progress.
2180 2180 thread->set_thread_state(_thread_blocked);
2181 2181 thread->java_suspend_self();
2182 2182 thread->set_thread_state(state);
2183 2183 // Make sure new state is seen by VM thread
2184 2184 if (os::is_MP()) {
2185 2185 if (UseMembar) {
2186 2186 // Force a fence between the write above and read below
2187 2187 OrderAccess::fence();
2188 2188 } else {
2189 2189 // Must use this rather than serialization page in particular on Windows
2190 2190 InterfaceSupport::serialize_memory(thread);
2191 2191 }
2192 2192 }
2193 2193 }
2194 2194
2195 2195 if (SafepointSynchronize::do_call_back()) {
2196 2196 // If we are safepointing, then block the caller which may not be
2197 2197 // the same as the target thread (see above).
2198 2198 SafepointSynchronize::block(curJT);
2199 2199 }
2200 2200
2201 2201 if (thread->is_deopt_suspend()) {
2202 2202 thread->clear_deopt_suspend();
2203 2203 RegisterMap map(thread, false);
2204 2204 frame f = thread->last_frame();
2205 2205 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
2206 2206 f = f.sender(&map);
2207 2207 }
2208 2208 if (f.id() == thread->must_deopt_id()) {
2209 2209 thread->clear_must_deopt_id();
2210 2210 f.deoptimize(thread);
2211 2211 } else {
2212 2212 fatal("missed deoptimization!");
2213 2213 }
2214 2214 }
2215 2215 }
2216 2216
2217 2217 // Slow path when the native==>VM/Java barriers detect a safepoint is in
2218 2218 // progress or when _suspend_flags is non-zero.
2219 2219 // Current thread needs to self-suspend if there is a suspend request and/or
2220 2220 // block if a safepoint is in progress.
2221 2221 // Also check for pending async exception (not including unsafe access error).
2222 2222 // Note only the native==>VM/Java barriers can call this function and when
2223 2223 // thread state is _thread_in_native_trans.
2224 2224 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
2225 2225 check_safepoint_and_suspend_for_native_trans(thread);
2226 2226
2227 2227 if (thread->has_async_exception()) {
2228 2228 // We are in _thread_in_native_trans state, don't handle unsafe
2229 2229 // access error since that may block.
2230 2230 thread->check_and_handle_async_exceptions(false);
2231 2231 }
2232 2232 }
2233 2233
2234 2234 // We need to guarantee the Threads_lock here, since resumes are not
2235 2235 // allowed during safepoint synchronization
2236 2236 // Can only resume from an external suspension
2237 2237 void JavaThread::java_resume() {
2238 2238 assert_locked_or_safepoint(Threads_lock);
2239 2239
2240 2240 // Sanity check: thread is gone, has started exiting or the thread
2241 2241 // was not externally suspended.
2242 2242 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
2243 2243 return;
2244 2244 }
2245 2245
2246 2246 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
2247 2247
2248 2248 clear_external_suspend();
2249 2249
2250 2250 if (is_ext_suspended()) {
2251 2251 clear_ext_suspended();
2252 2252 SR_lock()->notify_all();
2253 2253 }
2254 2254 }
2255 2255
2256 2256 void JavaThread::create_stack_guard_pages() {
2257 2257 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return;
2258 2258 address low_addr = stack_base() - stack_size();
2259 2259 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2260 2260
2261 2261 int allocate = os::allocate_stack_guard_pages();
2262 2262 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
2263 2263
2264 2264 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) {
2265 2265 warning("Attempt to allocate stack guard pages failed.");
2266 2266 return;
2267 2267 }
2268 2268
2269 2269 if (os::guard_memory((char *) low_addr, len)) {
2270 2270 _stack_guard_state = stack_guard_enabled;
2271 2271 } else {
2272 2272 warning("Attempt to protect stack guard pages failed.");
2273 2273 if (os::uncommit_memory((char *) low_addr, len)) {
2274 2274 warning("Attempt to deallocate stack guard pages failed.");
2275 2275 }
2276 2276 }
2277 2277 }
2278 2278
2279 2279 void JavaThread::remove_stack_guard_pages() {
2280 2280 if (_stack_guard_state == stack_guard_unused) return;
2281 2281 address low_addr = stack_base() - stack_size();
2282 2282 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size();
2283 2283
2284 2284 if (os::allocate_stack_guard_pages()) {
2285 2285 if (os::remove_stack_guard_pages((char *) low_addr, len)) {
2286 2286 _stack_guard_state = stack_guard_unused;
2287 2287 } else {
2288 2288 warning("Attempt to deallocate stack guard pages failed.");
2289 2289 }
2290 2290 } else {
2291 2291 if (_stack_guard_state == stack_guard_unused) return;
2292 2292 if (os::unguard_memory((char *) low_addr, len)) {
2293 2293 _stack_guard_state = stack_guard_unused;
2294 2294 } else {
2295 2295 warning("Attempt to unprotect stack guard pages failed.");
2296 2296 }
2297 2297 }
2298 2298 }
2299 2299
2300 2300 void JavaThread::enable_stack_yellow_zone() {
2301 2301 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2302 2302 assert(_stack_guard_state != stack_guard_enabled, "already enabled");
2303 2303
2304 2304 // The base notation is from the stacks point of view, growing downward.
2305 2305 // We need to adjust it to work correctly with guard_memory()
2306 2306 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2307 2307
2308 2308 guarantee(base < stack_base(),"Error calculating stack yellow zone");
2309 2309 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone");
2310 2310
2311 2311 if (os::guard_memory((char *) base, stack_yellow_zone_size())) {
2312 2312 _stack_guard_state = stack_guard_enabled;
2313 2313 } else {
2314 2314 warning("Attempt to guard stack yellow zone failed.");
2315 2315 }
2316 2316 enable_register_stack_guard();
2317 2317 }
2318 2318
2319 2319 void JavaThread::disable_stack_yellow_zone() {
2320 2320 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2321 2321 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled");
2322 2322
2323 2323 // Simply return if called for a thread that does not use guard pages.
2324 2324 if (_stack_guard_state == stack_guard_unused) return;
2325 2325
2326 2326 // The base notation is from the stacks point of view, growing downward.
2327 2327 // We need to adjust it to work correctly with guard_memory()
2328 2328 address base = stack_yellow_zone_base() - stack_yellow_zone_size();
2329 2329
2330 2330 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) {
2331 2331 _stack_guard_state = stack_guard_yellow_disabled;
2332 2332 } else {
2333 2333 warning("Attempt to unguard stack yellow zone failed.");
2334 2334 }
2335 2335 disable_register_stack_guard();
2336 2336 }
2337 2337
2338 2338 void JavaThread::enable_stack_red_zone() {
2339 2339 // The base notation is from the stacks point of view, growing downward.
2340 2340 // We need to adjust it to work correctly with guard_memory()
2341 2341 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2342 2342 address base = stack_red_zone_base() - stack_red_zone_size();
2343 2343
2344 2344 guarantee(base < stack_base(),"Error calculating stack red zone");
2345 2345 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone");
2346 2346
2347 2347 if(!os::guard_memory((char *) base, stack_red_zone_size())) {
2348 2348 warning("Attempt to guard stack red zone failed.");
2349 2349 }
2350 2350 }
2351 2351
2352 2352 void JavaThread::disable_stack_red_zone() {
2353 2353 // The base notation is from the stacks point of view, growing downward.
2354 2354 // We need to adjust it to work correctly with guard_memory()
2355 2355 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
2356 2356 address base = stack_red_zone_base() - stack_red_zone_size();
2357 2357 if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
2358 2358 warning("Attempt to unguard stack red zone failed.");
2359 2359 }
2360 2360 }
2361 2361
2362 2362 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
2363 2363 // ignore is there is no stack
2364 2364 if (!has_last_Java_frame()) return;
2365 2365 // traverse the stack frames. Starts from top frame.
2366 2366 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2367 2367 frame* fr = fst.current();
2368 2368 f(fr, fst.register_map());
2369 2369 }
2370 2370 }
2371 2371
2372 2372
2373 2373 #ifndef PRODUCT
2374 2374 // Deoptimization
2375 2375 // Function for testing deoptimization
2376 2376 void JavaThread::deoptimize() {
2377 2377 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2378 2378 StackFrameStream fst(this, UseBiasedLocking);
2379 2379 bool deopt = false; // Dump stack only if a deopt actually happens.
2380 2380 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
2381 2381 // Iterate over all frames in the thread and deoptimize
2382 2382 for(; !fst.is_done(); fst.next()) {
2383 2383 if(fst.current()->can_be_deoptimized()) {
2384 2384
2385 2385 if (only_at) {
2386 2386 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
2387 2387 // consists of comma or carriage return separated numbers so
2388 2388 // search for the current bci in that string.
2389 2389 address pc = fst.current()->pc();
2390 2390 nmethod* nm = (nmethod*) fst.current()->cb();
2391 2391 ScopeDesc* sd = nm->scope_desc_at( pc);
2392 2392 char buffer[8];
2393 2393 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
2394 2394 size_t len = strlen(buffer);
2395 2395 const char * found = strstr(DeoptimizeOnlyAt, buffer);
2396 2396 while (found != NULL) {
2397 2397 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
2398 2398 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
2399 2399 // Check that the bci found is bracketed by terminators.
2400 2400 break;
2401 2401 }
2402 2402 found = strstr(found + 1, buffer);
2403 2403 }
2404 2404 if (!found) {
2405 2405 continue;
2406 2406 }
2407 2407 }
2408 2408
2409 2409 if (DebugDeoptimization && !deopt) {
2410 2410 deopt = true; // One-time only print before deopt
2411 2411 tty->print_cr("[BEFORE Deoptimization]");
2412 2412 trace_frames();
2413 2413 trace_stack();
2414 2414 }
2415 2415 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2416 2416 }
2417 2417 }
2418 2418
2419 2419 if (DebugDeoptimization && deopt) {
2420 2420 tty->print_cr("[AFTER Deoptimization]");
2421 2421 trace_frames();
2422 2422 }
2423 2423 }
2424 2424
2425 2425
2426 2426 // Make zombies
2427 2427 void JavaThread::make_zombies() {
2428 2428 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2429 2429 if (fst.current()->can_be_deoptimized()) {
2430 2430 // it is a Java nmethod
2431 2431 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
2432 2432 nm->make_not_entrant();
2433 2433 }
2434 2434 }
2435 2435 }
2436 2436 #endif // PRODUCT
2437 2437
2438 2438
2439 2439 void JavaThread::deoptimized_wrt_marked_nmethods() {
2440 2440 if (!has_last_Java_frame()) return;
2441 2441 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass
2442 2442 StackFrameStream fst(this, UseBiasedLocking);
2443 2443 for(; !fst.is_done(); fst.next()) {
2444 2444 if (fst.current()->should_be_deoptimized()) {
2445 2445 Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
2446 2446 }
2447 2447 }
2448 2448 }
2449 2449
2450 2450
2451 2451 // GC support
2452 2452 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); }
2453 2453
2454 2454 void JavaThread::gc_epilogue() {
2455 2455 frames_do(frame_gc_epilogue);
2456 2456 }
2457 2457
2458 2458
2459 2459 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); }
2460 2460
2461 2461 void JavaThread::gc_prologue() {
2462 2462 frames_do(frame_gc_prologue);
2463 2463 }
2464 2464
2465 2465 // If the caller is a NamedThread, then remember, in the current scope,
2466 2466 // the given JavaThread in its _processed_thread field.
2467 2467 class RememberProcessedThread: public StackObj {
2468 2468 NamedThread* _cur_thr;
2469 2469 public:
2470 2470 RememberProcessedThread(JavaThread* jthr) {
2471 2471 Thread* thread = Thread::current();
2472 2472 if (thread->is_Named_thread()) {
2473 2473 _cur_thr = (NamedThread *)thread;
2474 2474 _cur_thr->set_processed_thread(jthr);
2475 2475 } else {
2476 2476 _cur_thr = NULL;
2477 2477 }
2478 2478 }
2479 2479
2480 2480 ~RememberProcessedThread() {
2481 2481 if (_cur_thr) {
2482 2482 _cur_thr->set_processed_thread(NULL);
2483 2483 }
2484 2484 }
2485 2485 };
2486 2486
2487 2487 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
2488 2488 // Verify that the deferred card marks have been flushed.
2489 2489 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
2490 2490
2491 2491 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do
2492 2492 // since there may be more than one thread using each ThreadProfiler.
2493 2493
2494 2494 // Traverse the GCHandles
2495 2495 Thread::oops_do(f, cf);
2496 2496
2497 2497 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2498 2498 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2499 2499
2500 2500 if (has_last_Java_frame()) {
2501 2501 // Record JavaThread to GC thread
2502 2502 RememberProcessedThread rpt(this);
2503 2503
2504 2504 // Traverse the privileged stack
2505 2505 if (_privileged_stack_top != NULL) {
2506 2506 _privileged_stack_top->oops_do(f);
2507 2507 }
2508 2508
2509 2509 // traverse the registered growable array
2510 2510 if (_array_for_gc != NULL) {
2511 2511 for (int index = 0; index < _array_for_gc->length(); index++) {
2512 2512 f->do_oop(_array_for_gc->adr_at(index));
2513 2513 }
2514 2514 }
2515 2515
2516 2516 // Traverse the monitor chunks
2517 2517 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
2518 2518 chunk->oops_do(f);
2519 2519 }
2520 2520
2521 2521 // Traverse the execution stack
2522 2522 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2523 2523 fst.current()->oops_do(f, cf, fst.register_map());
2524 2524 }
2525 2525 }
2526 2526
2527 2527 // callee_target is never live across a gc point so NULL it here should
2528 2528 // it still contain a methdOop.
2529 2529
2530 2530 set_callee_target(NULL);
2531 2531
2532 2532 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
2533 2533 // If we have deferred set_locals there might be oops waiting to be
2534 2534 // written
2535 2535 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
2536 2536 if (list != NULL) {
2537 2537 for (int i = 0; i < list->length(); i++) {
2538 2538 list->at(i)->oops_do(f);
2539 2539 }
2540 2540 }
2541 2541
2542 2542 // Traverse instance variables at the end since the GC may be moving things
2543 2543 // around using this function
2544 2544 f->do_oop((oop*) &_threadObj);
2545 2545 f->do_oop((oop*) &_vm_result);
2546 2546 f->do_oop((oop*) &_vm_result_2);
2547 2547 f->do_oop((oop*) &_exception_oop);
2548 2548 f->do_oop((oop*) &_pending_async_exception);
2549 2549
2550 2550 if (jvmti_thread_state() != NULL) {
2551 2551 jvmti_thread_state()->oops_do(f);
2552 2552 }
2553 2553 }
2554 2554
2555 2555 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
2556 2556 Thread::nmethods_do(cf); // (super method is a no-op)
2557 2557
2558 2558 assert( (!has_last_Java_frame() && java_call_counter() == 0) ||
2559 2559 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
2560 2560
2561 2561 if (has_last_Java_frame()) {
2562 2562 // Traverse the execution stack
2563 2563 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2564 2564 fst.current()->nmethods_do(cf);
2565 2565 }
2566 2566 }
2567 2567 }
2568 2568
2569 2569 // Printing
2570 2570 const char* _get_thread_state_name(JavaThreadState _thread_state) {
2571 2571 switch (_thread_state) {
2572 2572 case _thread_uninitialized: return "_thread_uninitialized";
2573 2573 case _thread_new: return "_thread_new";
2574 2574 case _thread_new_trans: return "_thread_new_trans";
2575 2575 case _thread_in_native: return "_thread_in_native";
2576 2576 case _thread_in_native_trans: return "_thread_in_native_trans";
2577 2577 case _thread_in_vm: return "_thread_in_vm";
2578 2578 case _thread_in_vm_trans: return "_thread_in_vm_trans";
2579 2579 case _thread_in_Java: return "_thread_in_Java";
2580 2580 case _thread_in_Java_trans: return "_thread_in_Java_trans";
2581 2581 case _thread_blocked: return "_thread_blocked";
2582 2582 case _thread_blocked_trans: return "_thread_blocked_trans";
2583 2583 default: return "unknown thread state";
2584 2584 }
2585 2585 }
2586 2586
2587 2587 #ifndef PRODUCT
2588 2588 void JavaThread::print_thread_state_on(outputStream *st) const {
2589 2589 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
2590 2590 };
2591 2591 void JavaThread::print_thread_state() const {
2592 2592 print_thread_state_on(tty);
2593 2593 };
2594 2594 #endif // PRODUCT
2595 2595
2596 2596 // Called by Threads::print() for VM_PrintThreads operation
2597 2597 void JavaThread::print_on(outputStream *st) const {
2598 2598 st->print("\"%s\" ", get_thread_name());
2599 2599 oop thread_oop = threadObj();
2600 2600 if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
2601 2601 Thread::print_on(st);
2602 2602 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
2603 2603 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
2604 2604 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) {
2605 2605 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
2606 2606 }
2607 2607 #ifndef PRODUCT
2608 2608 print_thread_state_on(st);
2609 2609 _safepoint_state->print_on(st);
2610 2610 #endif // PRODUCT
2611 2611 }
2612 2612
2613 2613 // Called by fatal error handler. The difference between this and
2614 2614 // JavaThread::print() is that we can't grab lock or allocate memory.
2615 2615 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
2616 2616 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
2617 2617 oop thread_obj = threadObj();
2618 2618 if (thread_obj != NULL) {
2619 2619 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
2620 2620 }
2621 2621 st->print(" [");
2622 2622 st->print("%s", _get_thread_state_name(_thread_state));
2623 2623 if (osthread()) {
2624 2624 st->print(", id=%d", osthread()->thread_id());
2625 2625 }
2626 2626 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
2627 2627 _stack_base - _stack_size, _stack_base);
2628 2628 st->print("]");
2629 2629 return;
2630 2630 }
2631 2631
2632 2632 // Verification
2633 2633
2634 2634 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
2635 2635
2636 2636 void JavaThread::verify() {
2637 2637 // Verify oops in the thread.
2638 2638 oops_do(&VerifyOopClosure::verify_oop, NULL);
2639 2639
2640 2640 // Verify the stack frames.
2641 2641 frames_do(frame_verify);
2642 2642 }
2643 2643
2644 2644 // CR 6300358 (sub-CR 2137150)
2645 2645 // Most callers of this method assume that it can't return NULL but a
2646 2646 // thread may not have a name whilst it is in the process of attaching to
2647 2647 // the VM - see CR 6412693, and there are places where a JavaThread can be
2648 2648 // seen prior to having it's threadObj set (eg JNI attaching threads and
2649 2649 // if vm exit occurs during initialization). These cases can all be accounted
2650 2650 // for such that this method never returns NULL.
2651 2651 const char* JavaThread::get_thread_name() const {
2652 2652 #ifdef ASSERT
2653 2653 // early safepoints can hit while current thread does not yet have TLS
2654 2654 if (!SafepointSynchronize::is_at_safepoint()) {
2655 2655 Thread *cur = Thread::current();
2656 2656 if (!(cur->is_Java_thread() && cur == this)) {
2657 2657 // Current JavaThreads are allowed to get their own name without
2658 2658 // the Threads_lock.
2659 2659 assert_locked_or_safepoint(Threads_lock);
2660 2660 }
2661 2661 }
2662 2662 #endif // ASSERT
2663 2663 return get_thread_name_string();
2664 2664 }
2665 2665
2666 2666 // Returns a non-NULL representation of this thread's name, or a suitable
2667 2667 // descriptive string if there is no set name
2668 2668 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
2669 2669 const char* name_str;
2670 2670 oop thread_obj = threadObj();
2671 2671 if (thread_obj != NULL) {
2672 2672 typeArrayOop name = java_lang_Thread::name(thread_obj);
2673 2673 if (name != NULL) {
2674 2674 if (buf == NULL) {
2675 2675 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2676 2676 }
2677 2677 else {
2678 2678 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen);
2679 2679 }
2680 2680 }
2681 2681 else if (is_attaching()) { // workaround for 6412693 - see 6404306
2682 2682 name_str = "<no-name - thread is attaching>";
2683 2683 }
2684 2684 else {
2685 2685 name_str = Thread::name();
2686 2686 }
2687 2687 }
2688 2688 else {
2689 2689 name_str = Thread::name();
2690 2690 }
2691 2691 assert(name_str != NULL, "unexpected NULL thread name");
2692 2692 return name_str;
2693 2693 }
2694 2694
2695 2695
2696 2696 const char* JavaThread::get_threadgroup_name() const {
2697 2697 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2698 2698 oop thread_obj = threadObj();
2699 2699 if (thread_obj != NULL) {
2700 2700 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2701 2701 if (thread_group != NULL) {
2702 2702 typeArrayOop name = java_lang_ThreadGroup::name(thread_group);
2703 2703 // ThreadGroup.name can be null
2704 2704 if (name != NULL) {
2705 2705 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2706 2706 return str;
2707 2707 }
2708 2708 }
2709 2709 }
2710 2710 return NULL;
2711 2711 }
2712 2712
2713 2713 const char* JavaThread::get_parent_name() const {
2714 2714 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
2715 2715 oop thread_obj = threadObj();
2716 2716 if (thread_obj != NULL) {
2717 2717 oop thread_group = java_lang_Thread::threadGroup(thread_obj);
2718 2718 if (thread_group != NULL) {
2719 2719 oop parent = java_lang_ThreadGroup::parent(thread_group);
2720 2720 if (parent != NULL) {
2721 2721 typeArrayOop name = java_lang_ThreadGroup::name(parent);
2722 2722 // ThreadGroup.name can be null
2723 2723 if (name != NULL) {
2724 2724 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
2725 2725 return str;
2726 2726 }
2727 2727 }
2728 2728 }
2729 2729 }
2730 2730 return NULL;
2731 2731 }
2732 2732
2733 2733 ThreadPriority JavaThread::java_priority() const {
2734 2734 oop thr_oop = threadObj();
2735 2735 if (thr_oop == NULL) return NormPriority; // Bootstrapping
2736 2736 ThreadPriority priority = java_lang_Thread::priority(thr_oop);
2737 2737 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
2738 2738 return priority;
2739 2739 }
2740 2740
2741 2741 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
2742 2742
2743 2743 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
2744 2744 // Link Java Thread object <-> C++ Thread
2745 2745
2746 2746 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
2747 2747 // and put it into a new Handle. The Handle "thread_oop" can then
2748 2748 // be used to pass the C++ thread object to other methods.
2749 2749
2750 2750 // Set the Java level thread object (jthread) field of the
2751 2751 // new thread (a JavaThread *) to C++ thread object using the
2752 2752 // "thread_oop" handle.
2753 2753
2754 2754 // Set the thread field (a JavaThread *) of the
2755 2755 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
2756 2756
2757 2757 Handle thread_oop(Thread::current(),
2758 2758 JNIHandles::resolve_non_null(jni_thread));
2759 2759 assert(instanceKlass::cast(thread_oop->klass())->is_linked(),
2760 2760 "must be initialized");
2761 2761 set_threadObj(thread_oop());
2762 2762 java_lang_Thread::set_thread(thread_oop(), this);
2763 2763
2764 2764 if (prio == NoPriority) {
2765 2765 prio = java_lang_Thread::priority(thread_oop());
2766 2766 assert(prio != NoPriority, "A valid priority should be present");
2767 2767 }
2768 2768
2769 2769 // Push the Java priority down to the native thread; needs Threads_lock
2770 2770 Thread::set_priority(this, prio);
2771 2771
2772 2772 // Add the new thread to the Threads list and set it in motion.
2773 2773 // We must have threads lock in order to call Threads::add.
2774 2774 // It is crucial that we do not block before the thread is
2775 2775 // added to the Threads list for if a GC happens, then the java_thread oop
2776 2776 // will not be visited by GC.
2777 2777 Threads::add(this);
2778 2778 }
2779 2779
2780 2780 oop JavaThread::current_park_blocker() {
2781 2781 // Support for JSR-166 locks
2782 2782 oop thread_oop = threadObj();
2783 2783 if (thread_oop != NULL &&
2784 2784 JDK_Version::current().supports_thread_park_blocker()) {
2785 2785 return java_lang_Thread::park_blocker(thread_oop);
2786 2786 }
2787 2787 return NULL;
2788 2788 }
2789 2789
2790 2790
2791 2791 void JavaThread::print_stack_on(outputStream* st) {
2792 2792 if (!has_last_Java_frame()) return;
2793 2793 ResourceMark rm;
2794 2794 HandleMark hm;
2795 2795
2796 2796 RegisterMap reg_map(this);
2797 2797 vframe* start_vf = last_java_vframe(®_map);
2798 2798 int count = 0;
2799 2799 for (vframe* f = start_vf; f; f = f->sender() ) {
2800 2800 if (f->is_java_frame()) {
2801 2801 javaVFrame* jvf = javaVFrame::cast(f);
2802 2802 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
2803 2803
2804 2804 // Print out lock information
2805 2805 if (JavaMonitorsInStackTrace) {
2806 2806 jvf->print_lock_info_on(st, count);
2807 2807 }
2808 2808 } else {
2809 2809 // Ignore non-Java frames
2810 2810 }
2811 2811
2812 2812 // Bail-out case for too deep stacks
2813 2813 count++;
2814 2814 if (MaxJavaStackTraceDepth == count) return;
2815 2815 }
2816 2816 }
2817 2817
2818 2818
2819 2819 // JVMTI PopFrame support
2820 2820 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
2821 2821 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
2822 2822 if (in_bytes(size_in_bytes) != 0) {
2823 2823 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes));
2824 2824 _popframe_preserved_args_size = in_bytes(size_in_bytes);
2825 2825 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
2826 2826 }
2827 2827 }
2828 2828
2829 2829 void* JavaThread::popframe_preserved_args() {
2830 2830 return _popframe_preserved_args;
2831 2831 }
2832 2832
2833 2833 ByteSize JavaThread::popframe_preserved_args_size() {
2834 2834 return in_ByteSize(_popframe_preserved_args_size);
2835 2835 }
2836 2836
2837 2837 WordSize JavaThread::popframe_preserved_args_size_in_words() {
2838 2838 int sz = in_bytes(popframe_preserved_args_size());
2839 2839 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
2840 2840 return in_WordSize(sz / wordSize);
2841 2841 }
2842 2842
2843 2843 void JavaThread::popframe_free_preserved_args() {
2844 2844 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
2845 2845 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
2846 2846 _popframe_preserved_args = NULL;
2847 2847 _popframe_preserved_args_size = 0;
2848 2848 }
2849 2849
2850 2850 #ifndef PRODUCT
2851 2851
2852 2852 void JavaThread::trace_frames() {
2853 2853 tty->print_cr("[Describe stack]");
2854 2854 int frame_no = 1;
2855 2855 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) {
2856 2856 tty->print(" %d. ", frame_no++);
2857 2857 fst.current()->print_value_on(tty,this);
2858 2858 tty->cr();
2859 2859 }
2860 2860 }
2861 2861
2862 2862
2863 2863 void JavaThread::trace_stack_from(vframe* start_vf) {
2864 2864 ResourceMark rm;
2865 2865 int vframe_no = 1;
2866 2866 for (vframe* f = start_vf; f; f = f->sender() ) {
2867 2867 if (f->is_java_frame()) {
2868 2868 javaVFrame::cast(f)->print_activation(vframe_no++);
2869 2869 } else {
2870 2870 f->print();
2871 2871 }
2872 2872 if (vframe_no > StackPrintLimit) {
2873 2873 tty->print_cr("...<more frames>...");
2874 2874 return;
2875 2875 }
2876 2876 }
2877 2877 }
2878 2878
2879 2879
2880 2880 void JavaThread::trace_stack() {
2881 2881 if (!has_last_Java_frame()) return;
2882 2882 ResourceMark rm;
2883 2883 HandleMark hm;
2884 2884 RegisterMap reg_map(this);
2885 2885 trace_stack_from(last_java_vframe(®_map));
2886 2886 }
2887 2887
2888 2888
2889 2889 #endif // PRODUCT
2890 2890
2891 2891
2892 2892 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
2893 2893 assert(reg_map != NULL, "a map must be given");
2894 2894 frame f = last_frame();
2895 2895 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) {
2896 2896 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2897 2897 }
2898 2898 return NULL;
2899 2899 }
2900 2900
2901 2901
2902 2902 klassOop JavaThread::security_get_caller_class(int depth) {
2903 2903 vframeStream vfst(this);
2904 2904 vfst.security_get_caller_frame(depth);
2905 2905 if (!vfst.at_end()) {
2906 2906 return vfst.method()->method_holder();
2907 2907 }
2908 2908 return NULL;
2909 2909 }
2910 2910
2911 2911 static void compiler_thread_entry(JavaThread* thread, TRAPS) {
2912 2912 assert(thread->is_Compiler_thread(), "must be compiler thread");
2913 2913 CompileBroker::compiler_thread_loop();
2914 2914 }
2915 2915
2916 2916 // Create a CompilerThread
2917 2917 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters)
2918 2918 : JavaThread(&compiler_thread_entry) {
2919 2919 _env = NULL;
2920 2920 _log = NULL;
2921 2921 _task = NULL;
2922 2922 _queue = queue;
2923 2923 _counters = counters;
2924 2924 _buffer_blob = NULL;
2925 2925
2926 2926 #ifndef PRODUCT
2927 2927 _ideal_graph_printer = NULL;
2928 2928 #endif
2929 2929 }
2930 2930
2931 2931
2932 2932 // ======= Threads ========
2933 2933
2934 2934 // The Threads class links together all active threads, and provides
2935 2935 // operations over all threads. It is protected by its own Mutex
2936 2936 // lock, which is also used in other contexts to protect thread
2937 2937 // operations from having the thread being operated on from exiting
2938 2938 // and going away unexpectedly (e.g., safepoint synchronization)
2939 2939
2940 2940 JavaThread* Threads::_thread_list = NULL;
2941 2941 int Threads::_number_of_threads = 0;
2942 2942 int Threads::_number_of_non_daemon_threads = 0;
2943 2943 int Threads::_return_code = 0;
2944 2944 size_t JavaThread::_stack_size_at_create = 0;
2945 2945
2946 2946 // All JavaThreads
2947 2947 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
2948 2948
2949 2949 void os_stream();
2950 2950
2951 2951 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
2952 2952 void Threads::threads_do(ThreadClosure* tc) {
2953 2953 assert_locked_or_safepoint(Threads_lock);
2954 2954 // ALL_JAVA_THREADS iterates through all JavaThreads
2955 2955 ALL_JAVA_THREADS(p) {
2956 2956 tc->do_thread(p);
2957 2957 }
2958 2958 // Someday we could have a table or list of all non-JavaThreads.
2959 2959 // For now, just manually iterate through them.
2960 2960 tc->do_thread(VMThread::vm_thread());
2961 2961 Universe::heap()->gc_threads_do(tc);
2962 2962 WatcherThread *wt = WatcherThread::watcher_thread();
2963 2963 // Strictly speaking, the following NULL check isn't sufficient to make sure
2964 2964 // the data for WatcherThread is still valid upon being examined. However,
2965 2965 // considering that WatchThread terminates when the VM is on the way to
2966 2966 // exit at safepoint, the chance of the above is extremely small. The right
2967 2967 // way to prevent termination of WatcherThread would be to acquire
2968 2968 // Terminator_lock, but we can't do that without violating the lock rank
2969 2969 // checking in some cases.
2970 2970 if (wt != NULL)
2971 2971 tc->do_thread(wt);
2972 2972
2973 2973 // If CompilerThreads ever become non-JavaThreads, add them here
2974 2974 }
2975 2975
2976 2976 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
2977 2977
2978 2978 extern void JDK_Version_init();
2979 2979
2980 2980 // Check version
2981 2981 if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
2982 2982
2983 2983 // Initialize the output stream module
2984 2984 ostream_init();
2985 2985
2986 2986 // Process java launcher properties.
2987 2987 Arguments::process_sun_java_launcher_properties(args);
2988 2988
2989 2989 // Initialize the os module before using TLS
2990 2990 os::init();
2991 2991
2992 2992 // Initialize system properties.
2993 2993 Arguments::init_system_properties();
2994 2994
2995 2995 // So that JDK version can be used as a discrimintor when parsing arguments
2996 2996 JDK_Version_init();
2997 2997
2998 2998 // Update/Initialize System properties after JDK version number is known
2999 2999 Arguments::init_version_specific_system_properties();
3000 3000
3001 3001 // Parse arguments
3002 3002 jint parse_result = Arguments::parse(args);
3003 3003 if (parse_result != JNI_OK) return parse_result;
3004 3004
3005 3005 if (PauseAtStartup) {
3006 3006 os::pause();
3007 3007 }
3008 3008
3009 3009 HS_DTRACE_PROBE(hotspot, vm__init__begin);
3010 3010
3011 3011 // Record VM creation timing statistics
3012 3012 TraceVmCreationTime create_vm_timer;
3013 3013 create_vm_timer.start();
3014 3014
3015 3015 // Timing (must come after argument parsing)
3016 3016 TraceTime timer("Create VM", TraceStartupTime);
3017 3017
3018 3018 // Initialize the os module after parsing the args
3019 3019 jint os_init_2_result = os::init_2();
3020 3020 if (os_init_2_result != JNI_OK) return os_init_2_result;
3021 3021
3022 3022 // Initialize output stream logging
3023 3023 ostream_init_log();
3024 3024
3025 3025 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad
3026 3026 // Must be before create_vm_init_agents()
3027 3027 if (Arguments::init_libraries_at_startup()) {
3028 3028 convert_vm_init_libraries_to_agents();
3029 3029 }
3030 3030
3031 3031 // Launch -agentlib/-agentpath and converted -Xrun agents
3032 3032 if (Arguments::init_agents_at_startup()) {
3033 3033 create_vm_init_agents();
3034 3034 }
3035 3035
3036 3036 // Initialize Threads state
3037 3037 _thread_list = NULL;
3038 3038 _number_of_threads = 0;
3039 3039 _number_of_non_daemon_threads = 0;
3040 3040
3041 3041 // Initialize TLS
3042 3042 ThreadLocalStorage::init();
3043 3043
3044 3044 // Initialize global data structures and create system classes in heap
3045 3045 vm_init_globals();
3046 3046
3047 3047 // Attach the main thread to this os thread
3048 3048 JavaThread* main_thread = new JavaThread();
3049 3049 main_thread->set_thread_state(_thread_in_vm);
3050 3050 // must do this before set_active_handles and initialize_thread_local_storage
3051 3051 // Note: on solaris initialize_thread_local_storage() will (indirectly)
3052 3052 // change the stack size recorded here to one based on the java thread
3053 3053 // stacksize. This adjusted size is what is used to figure the placement
3054 3054 // of the guard pages.
3055 3055 main_thread->record_stack_base_and_size();
3056 3056 main_thread->initialize_thread_local_storage();
3057 3057
3058 3058 main_thread->set_active_handles(JNIHandleBlock::allocate_block());
3059 3059
3060 3060 if (!main_thread->set_as_starting_thread()) {
3061 3061 vm_shutdown_during_initialization(
3062 3062 "Failed necessary internal allocation. Out of swap space");
3063 3063 delete main_thread;
3064 3064 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3065 3065 return JNI_ENOMEM;
3066 3066 }
3067 3067
3068 3068 // Enable guard page *after* os::create_main_thread(), otherwise it would
3069 3069 // crash Linux VM, see notes in os_linux.cpp.
3070 3070 main_thread->create_stack_guard_pages();
3071 3071
3072 3072 // Initialize Java-Level synchronization subsystem
3073 3073 ObjectMonitor::Initialize() ;
3074 3074
3075 3075 // Initialize global modules
3076 3076 jint status = init_globals();
3077 3077 if (status != JNI_OK) {
3078 3078 delete main_thread;
3079 3079 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
3080 3080 return status;
3081 3081 }
3082 3082
3083 3083 // Should be done after the heap is fully created
3084 3084 main_thread->cache_global_variables();
3085 3085
3086 3086 HandleMark hm;
3087 3087
3088 3088 { MutexLocker mu(Threads_lock);
3089 3089 Threads::add(main_thread);
3090 3090 }
3091 3091
3092 3092 // Any JVMTI raw monitors entered in onload will transition into
3093 3093 // real raw monitor. VM is setup enough here for raw monitor enter.
3094 3094 JvmtiExport::transition_pending_onload_raw_monitors();
3095 3095
3096 3096 if (VerifyBeforeGC &&
3097 3097 Universe::heap()->total_collections() >= VerifyGCStartAt) {
3098 3098 Universe::heap()->prepare_for_verify();
3099 3099 Universe::verify(); // make sure we're starting with a clean slate
3100 3100 }
3101 3101
3102 3102 // Create the VMThread
3103 3103 { TraceTime timer("Start VMThread", TraceStartupTime);
3104 3104 VMThread::create();
3105 3105 Thread* vmthread = VMThread::vm_thread();
3106 3106
3107 3107 if (!os::create_thread(vmthread, os::vm_thread))
3108 3108 vm_exit_during_initialization("Cannot create VM thread. Out of system resources.");
3109 3109
3110 3110 // Wait for the VM thread to become ready, and VMThread::run to initialize
3111 3111 // Monitors can have spurious returns, must always check another state flag
3112 3112 {
3113 3113 MutexLocker ml(Notify_lock);
3114 3114 os::start_thread(vmthread);
3115 3115 while (vmthread->active_handles() == NULL) {
3116 3116 Notify_lock->wait();
3117 3117 }
3118 3118 }
3119 3119 }
3120 3120
3121 3121 assert (Universe::is_fully_initialized(), "not initialized");
3122 3122 EXCEPTION_MARK;
3123 3123
3124 3124 // At this point, the Universe is initialized, but we have not executed
3125 3125 // any byte code. Now is a good time (the only time) to dump out the
3126 3126 // internal state of the JVM for sharing.
3127 3127
3128 3128 if (DumpSharedSpaces) {
3129 3129 Universe::heap()->preload_and_dump(CHECK_0);
3130 3130 ShouldNotReachHere();
3131 3131 }
3132 3132
3133 3133 // Always call even when there are not JVMTI environments yet, since environments
3134 3134 // may be attached late and JVMTI must track phases of VM execution
3135 3135 JvmtiExport::enter_start_phase();
3136 3136
3137 3137 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
3138 3138 JvmtiExport::post_vm_start();
3139 3139
3140 3140 {
3141 3141 TraceTime timer("Initialize java.lang classes", TraceStartupTime);
3142 3142
3143 3143 if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
3144 3144 create_vm_init_libraries();
3145 3145 }
3146 3146
3147 3147 if (InitializeJavaLangString) {
3148 3148 initialize_class(vmSymbols::java_lang_String(), CHECK_0);
3149 3149 } else {
3150 3150 warning("java.lang.String not initialized");
3151 3151 }
3152 3152
3153 3153 if (AggressiveOpts) {
3154 3154 {
3155 3155 // Forcibly initialize java/util/HashMap and mutate the private
3156 3156 // static final "frontCacheEnabled" field before we start creating instances
3157 3157 #ifdef ASSERT
3158 3158 klassOop tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3159 3159 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet");
3160 3160 #endif
3161 3161 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0);
3162 3162 KlassHandle k = KlassHandle(THREAD, k_o);
3163 3163 guarantee(k.not_null(), "Must find java/util/HashMap");
3164 3164 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3165 3165 ik->initialize(CHECK_0);
3166 3166 fieldDescriptor fd;
3167 3167 // Possible we might not find this field; if so, don't break
3168 3168 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3169 3169 k()->java_mirror()->bool_field_put(fd.offset(), true);
3170 3170 }
3171 3171 }
3172 3172
3173 3173 if (UseStringCache) {
3174 3174 // Forcibly initialize java/lang/StringValue and mutate the private
3175 3175 // static final "stringCacheEnabled" field before we start creating instances
3176 3176 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0);
3177 3177 // Possible that StringValue isn't present: if so, silently don't break
3178 3178 if (k_o != NULL) {
3179 3179 KlassHandle k = KlassHandle(THREAD, k_o);
3180 3180 instanceKlassHandle ik = instanceKlassHandle(THREAD, k());
3181 3181 ik->initialize(CHECK_0);
3182 3182 fieldDescriptor fd;
3183 3183 // Possible we might not find this field: if so, silently don't break
3184 3184 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) {
3185 3185 k()->java_mirror()->bool_field_put(fd.offset(), true);
3186 3186 }
3187 3187 }
3188 3188 }
3189 3189 }
3190 3190
3191 3191 // Initialize java_lang.System (needed before creating the thread)
3192 3192 if (InitializeJavaLangSystem) {
3193 3193 initialize_class(vmSymbols::java_lang_System(), CHECK_0);
3194 3194 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0);
3195 3195 Handle thread_group = create_initial_thread_group(CHECK_0);
3196 3196 Universe::set_main_thread_group(thread_group());
3197 3197 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0);
3198 3198 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0);
3199 3199 main_thread->set_threadObj(thread_object);
3200 3200 // Set thread status to running since main thread has
3201 3201 // been started and running.
3202 3202 java_lang_Thread::set_thread_status(thread_object,
3203 3203 java_lang_Thread::RUNNABLE);
3204 3204
3205 3205 // The VM preresolve methods to these classes. Make sure that get initialized
3206 3206 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0);
3207 3207 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0);
3208 3208 // The VM creates & returns objects of this class. Make sure it's initialized.
3209 3209 initialize_class(vmSymbols::java_lang_Class(), CHECK_0);
3210 3210 call_initializeSystemClass(CHECK_0);
3211 3211 } else {
3212 3212 warning("java.lang.System not initialized");
3213 3213 }
3214 3214
3215 3215 // an instance of OutOfMemory exception has been allocated earlier
3216 3216 if (InitializeJavaLangExceptionsErrors) {
3217 3217 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0);
3218 3218 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0);
3219 3219 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0);
3220 3220 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0);
3221 3221 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0);
|
↓ open down ↓ |
3221 lines elided |
↑ open up ↑ |
3222 3222 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0);
3223 3223 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0);
3224 3224 } else {
3225 3225 warning("java.lang.OutOfMemoryError has not been initialized");
3226 3226 warning("java.lang.NullPointerException has not been initialized");
3227 3227 warning("java.lang.ClassCastException has not been initialized");
3228 3228 warning("java.lang.ArrayStoreException has not been initialized");
3229 3229 warning("java.lang.ArithmeticException has not been initialized");
3230 3230 warning("java.lang.StackOverflowError has not been initialized");
3231 3231 }
3232 - }
3232 + }
3233 3233
3234 3234 // See : bugid 4211085.
3235 3235 // Background : the static initializer of java.lang.Compiler tries to read
3236 3236 // property"java.compiler" and read & write property "java.vm.info".
3237 3237 // When a security manager is installed through the command line
3238 3238 // option "-Djava.security.manager", the above properties are not
3239 3239 // readable and the static initializer for java.lang.Compiler fails
3240 3240 // resulting in a NoClassDefFoundError. This can happen in any
3241 3241 // user code which calls methods in java.lang.Compiler.
3242 3242 // Hack : the hack is to pre-load and initialize this class, so that only
3243 3243 // system domains are on the stack when the properties are read.
3244 3244 // Currently even the AWT code has calls to methods in java.lang.Compiler.
3245 3245 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT.
3246 3246 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and
3247 3247 // read and write"java.vm.info" in the default policy file. See bugid 4211383
3248 3248 // Once that is done, we should remove this hack.
3249 3249 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0);
3250 3250
3251 3251 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to
3252 3252 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot
3253 3253 // compiler does not get loaded through java.lang.Compiler). "java -version" with the
3254 3254 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here.
3255 3255 // This should also be taken out as soon as 4211383 gets fixed.
3256 3256 reset_vm_info_property(CHECK_0);
3257 3257
3258 3258 quicken_jni_functions();
3259 3259
3260 3260 // Set flag that basic initialization has completed. Used by exceptions and various
3261 3261 // debug stuff, that does not work until all basic classes have been initialized.
3262 3262 set_init_completed();
3263 3263
3264 3264 HS_DTRACE_PROBE(hotspot, vm__init__end);
3265 3265
3266 3266 // record VM initialization completion time
3267 3267 Management::record_vm_init_completed();
3268 3268
3269 3269 // Compute system loader. Note that this has to occur after set_init_completed, since
3270 3270 // valid exceptions may be thrown in the process.
3271 3271 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and
3272 3272 // set_init_completed has just been called, causing exceptions not to be shortcut
3273 3273 // anymore. We call vm_exit_during_initialization directly instead.
3274 3274 SystemDictionary::compute_java_system_loader(THREAD);
3275 3275 if (HAS_PENDING_EXCEPTION) {
3276 3276 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3277 3277 }
3278 3278
3279 3279 #ifndef SERIALGC
3280 3280 // Support for ConcurrentMarkSweep. This should be cleaned up
3281 3281 // and better encapsulated. The ugly nested if test would go away
3282 3282 // once things are properly refactored. XXX YSR
3283 3283 if (UseConcMarkSweepGC || UseG1GC) {
3284 3284 if (UseConcMarkSweepGC) {
3285 3285 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD);
3286 3286 } else {
3287 3287 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD);
3288 3288 }
3289 3289 if (HAS_PENDING_EXCEPTION) {
3290 3290 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION));
3291 3291 }
3292 3292 }
3293 3293 #endif // SERIALGC
3294 3294
3295 3295 // Always call even when there are not JVMTI environments yet, since environments
3296 3296 // may be attached late and JVMTI must track phases of VM execution
3297 3297 JvmtiExport::enter_live_phase();
3298 3298
3299 3299 // Signal Dispatcher needs to be started before VMInit event is posted
3300 3300 os::signal_init();
3301 3301
3302 3302 // Start Attach Listener if +StartAttachListener or it can't be started lazily
3303 3303 if (!DisableAttachMechanism) {
3304 3304 if (StartAttachListener || AttachListener::init_at_startup()) {
3305 3305 AttachListener::init();
3306 3306 }
3307 3307 }
3308 3308
3309 3309 // Launch -Xrun agents
3310 3310 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP
3311 3311 // back-end can launch with -Xdebug -Xrunjdwp.
3312 3312 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
3313 3313 create_vm_init_libraries();
3314 3314 }
3315 3315
3316 3316 // Notify JVMTI agents that VM initialization is complete - nop if no agents.
3317 3317 JvmtiExport::post_vm_initialized();
3318 3318
3319 3319 Chunk::start_chunk_pool_cleaner_task();
3320 3320
3321 3321 // initialize compiler(s)
3322 3322 CompileBroker::compilation_init();
3323 3323
3324 3324 Management::initialize(THREAD);
3325 3325 if (HAS_PENDING_EXCEPTION) {
3326 3326 // management agent fails to start possibly due to
3327 3327 // configuration problem and is responsible for printing
3328 3328 // stack trace if appropriate. Simply exit VM.
3329 3329 vm_exit(1);
3330 3330 }
3331 3331
3332 3332 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true);
3333 3333 if (Arguments::has_alloc_profile()) AllocationProfiler::engage();
3334 3334 if (MemProfiling) MemProfiler::engage();
3335 3335 StatSampler::engage();
3336 3336 if (CheckJNICalls) JniPeriodicChecker::engage();
3337 3337
3338 3338 BiasedLocking::init();
3339 3339
3340 3340 if (JDK_Version::current().post_vm_init_hook_enabled()) {
3341 3341 call_postVMInitHook(THREAD);
3342 3342 // The Java side of PostVMInitHook.run must deal with all
3343 3343 // exceptions and provide means of diagnosis.
3344 3344 if (HAS_PENDING_EXCEPTION) {
3345 3345 CLEAR_PENDING_EXCEPTION;
3346 3346 }
3347 3347 }
3348 3348
3349 3349 // Start up the WatcherThread if there are any periodic tasks
3350 3350 // NOTE: All PeriodicTasks should be registered by now. If they
3351 3351 // aren't, late joiners might appear to start slowly (we might
3352 3352 // take a while to process their first tick).
3353 3353 if (PeriodicTask::num_tasks() > 0) {
3354 3354 WatcherThread::start();
3355 3355 }
3356 3356
3357 3357 // Give os specific code one last chance to start
3358 3358 os::init_3();
3359 3359
3360 3360 create_vm_timer.end();
3361 3361 return JNI_OK;
3362 3362 }
3363 3363
3364 3364 // type for the Agent_OnLoad and JVM_OnLoad entry points
3365 3365 extern "C" {
3366 3366 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
3367 3367 }
3368 3368 // Find a command line agent library and return its entry point for
3369 3369 // -agentlib: -agentpath: -Xrun
3370 3370 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
3371 3371 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) {
3372 3372 OnLoadEntry_t on_load_entry = NULL;
3373 3373 void *library = agent->os_lib(); // check if we have looked it up before
3374 3374
3375 3375 if (library == NULL) {
3376 3376 char buffer[JVM_MAXPATHLEN];
3377 3377 char ebuf[1024];
3378 3378 const char *name = agent->name();
3379 3379 const char *msg = "Could not find agent library ";
3380 3380
3381 3381 if (agent->is_absolute_path()) {
3382 3382 library = os::dll_load(name, ebuf, sizeof ebuf);
3383 3383 if (library == NULL) {
3384 3384 const char *sub_msg = " in absolute path, with error: ";
3385 3385 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3386 3386 char *buf = NEW_C_HEAP_ARRAY(char, len);
3387 3387 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3388 3388 // If we can't find the agent, exit.
3389 3389 vm_exit_during_initialization(buf, NULL);
3390 3390 FREE_C_HEAP_ARRAY(char, buf);
3391 3391 }
3392 3392 } else {
3393 3393 // Try to load the agent from the standard dll directory
3394 3394 os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name);
3395 3395 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3396 3396 #ifdef KERNEL
3397 3397 // Download instrument dll
3398 3398 if (library == NULL && strcmp(name, "instrument") == 0) {
3399 3399 char *props = Arguments::get_kernel_properties();
3400 3400 char *home = Arguments::get_java_home();
3401 3401 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false"
3402 3402 " sun.jkernel.DownloadManager -download client_jvm";
3403 3403 size_t length = strlen(props) + strlen(home) + strlen(fmt) + 1;
3404 3404 char *cmd = NEW_C_HEAP_ARRAY(char, length);
3405 3405 jio_snprintf(cmd, length, fmt, home, props);
3406 3406 int status = os::fork_and_exec(cmd);
3407 3407 FreeHeap(props);
3408 3408 if (status == -1) {
3409 3409 warning(cmd);
3410 3410 vm_exit_during_initialization("fork_and_exec failed: %s",
3411 3411 strerror(errno));
3412 3412 }
3413 3413 FREE_C_HEAP_ARRAY(char, cmd);
3414 3414 // when this comes back the instrument.dll should be where it belongs.
3415 3415 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3416 3416 }
3417 3417 #endif // KERNEL
3418 3418 if (library == NULL) { // Try the local directory
3419 3419 char ns[1] = {0};
3420 3420 os::dll_build_name(buffer, sizeof(buffer), ns, name);
3421 3421 library = os::dll_load(buffer, ebuf, sizeof ebuf);
3422 3422 if (library == NULL) {
3423 3423 const char *sub_msg = " on the library path, with error: ";
3424 3424 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
3425 3425 char *buf = NEW_C_HEAP_ARRAY(char, len);
3426 3426 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
3427 3427 // If we can't find the agent, exit.
3428 3428 vm_exit_during_initialization(buf, NULL);
3429 3429 FREE_C_HEAP_ARRAY(char, buf);
3430 3430 }
3431 3431 }
3432 3432 }
3433 3433 agent->set_os_lib(library);
3434 3434 }
3435 3435
3436 3436 // Find the OnLoad function.
3437 3437 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) {
3438 3438 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index]));
3439 3439 if (on_load_entry != NULL) break;
3440 3440 }
3441 3441 return on_load_entry;
3442 3442 }
3443 3443
3444 3444 // Find the JVM_OnLoad entry point
3445 3445 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
3446 3446 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
3447 3447 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3448 3448 }
3449 3449
3450 3450 // Find the Agent_OnLoad entry point
3451 3451 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
3452 3452 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
3453 3453 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
3454 3454 }
3455 3455
3456 3456 // For backwards compatibility with -Xrun
3457 3457 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
3458 3458 // treated like -agentpath:
3459 3459 // Must be called before agent libraries are created
3460 3460 void Threads::convert_vm_init_libraries_to_agents() {
3461 3461 AgentLibrary* agent;
3462 3462 AgentLibrary* next;
3463 3463
3464 3464 for (agent = Arguments::libraries(); agent != NULL; agent = next) {
3465 3465 next = agent->next(); // cache the next agent now as this agent may get moved off this list
3466 3466 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3467 3467
3468 3468 // If there is an JVM_OnLoad function it will get called later,
3469 3469 // otherwise see if there is an Agent_OnLoad
3470 3470 if (on_load_entry == NULL) {
3471 3471 on_load_entry = lookup_agent_on_load(agent);
3472 3472 if (on_load_entry != NULL) {
3473 3473 // switch it to the agent list -- so that Agent_OnLoad will be called,
3474 3474 // JVM_OnLoad won't be attempted and Agent_OnUnload will
3475 3475 Arguments::convert_library_to_agent(agent);
3476 3476 } else {
3477 3477 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
3478 3478 }
3479 3479 }
3480 3480 }
3481 3481 }
3482 3482
3483 3483 // Create agents for -agentlib: -agentpath: and converted -Xrun
3484 3484 // Invokes Agent_OnLoad
3485 3485 // Called very early -- before JavaThreads exist
3486 3486 void Threads::create_vm_init_agents() {
3487 3487 extern struct JavaVM_ main_vm;
3488 3488 AgentLibrary* agent;
3489 3489
3490 3490 JvmtiExport::enter_onload_phase();
3491 3491 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3492 3492 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent);
3493 3493
3494 3494 if (on_load_entry != NULL) {
3495 3495 // Invoke the Agent_OnLoad function
3496 3496 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3497 3497 if (err != JNI_OK) {
3498 3498 vm_exit_during_initialization("agent library failed to init", agent->name());
3499 3499 }
3500 3500 } else {
3501 3501 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
3502 3502 }
3503 3503 }
3504 3504 JvmtiExport::enter_primordial_phase();
3505 3505 }
3506 3506
3507 3507 extern "C" {
3508 3508 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
3509 3509 }
3510 3510
3511 3511 void Threads::shutdown_vm_agents() {
3512 3512 // Send any Agent_OnUnload notifications
3513 3513 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
3514 3514 extern struct JavaVM_ main_vm;
3515 3515 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
3516 3516
3517 3517 // Find the Agent_OnUnload function.
3518 3518 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) {
3519 3519 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
3520 3520 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index]));
3521 3521
3522 3522 // Invoke the Agent_OnUnload function
3523 3523 if (unload_entry != NULL) {
3524 3524 JavaThread* thread = JavaThread::current();
3525 3525 ThreadToNativeFromVM ttn(thread);
3526 3526 HandleMark hm(thread);
3527 3527 (*unload_entry)(&main_vm);
3528 3528 break;
3529 3529 }
3530 3530 }
3531 3531 }
3532 3532 }
3533 3533
3534 3534 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
3535 3535 // Invokes JVM_OnLoad
3536 3536 void Threads::create_vm_init_libraries() {
3537 3537 extern struct JavaVM_ main_vm;
3538 3538 AgentLibrary* agent;
3539 3539
3540 3540 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
3541 3541 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
3542 3542
3543 3543 if (on_load_entry != NULL) {
3544 3544 // Invoke the JVM_OnLoad function
3545 3545 JavaThread* thread = JavaThread::current();
3546 3546 ThreadToNativeFromVM ttn(thread);
3547 3547 HandleMark hm(thread);
3548 3548 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
3549 3549 if (err != JNI_OK) {
3550 3550 vm_exit_during_initialization("-Xrun library failed to init", agent->name());
3551 3551 }
3552 3552 } else {
3553 3553 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
3554 3554 }
3555 3555 }
3556 3556 }
3557 3557
3558 3558 // Last thread running calls java.lang.Shutdown.shutdown()
3559 3559 void JavaThread::invoke_shutdown_hooks() {
3560 3560 HandleMark hm(this);
3561 3561
3562 3562 // We could get here with a pending exception, if so clear it now.
3563 3563 if (this->has_pending_exception()) {
3564 3564 this->clear_pending_exception();
3565 3565 }
3566 3566
3567 3567 EXCEPTION_MARK;
3568 3568 klassOop k =
3569 3569 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
3570 3570 THREAD);
3571 3571 if (k != NULL) {
3572 3572 // SystemDictionary::resolve_or_null will return null if there was
3573 3573 // an exception. If we cannot load the Shutdown class, just don't
3574 3574 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
3575 3575 // and finalizers (if runFinalizersOnExit is set) won't be run.
3576 3576 // Note that if a shutdown hook was registered or runFinalizersOnExit
3577 3577 // was called, the Shutdown class would have already been loaded
3578 3578 // (Runtime.addShutdownHook and runFinalizersOnExit will load it).
3579 3579 instanceKlassHandle shutdown_klass (THREAD, k);
3580 3580 JavaValue result(T_VOID);
3581 3581 JavaCalls::call_static(&result,
3582 3582 shutdown_klass,
3583 3583 vmSymbols::shutdown_method_name(),
3584 3584 vmSymbols::void_method_signature(),
3585 3585 THREAD);
3586 3586 }
3587 3587 CLEAR_PENDING_EXCEPTION;
3588 3588 }
3589 3589
3590 3590 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
3591 3591 // the program falls off the end of main(). Another VM exit path is through
3592 3592 // vm_exit() when the program calls System.exit() to return a value or when
3593 3593 // there is a serious error in VM. The two shutdown paths are not exactly
3594 3594 // the same, but they share Shutdown.shutdown() at Java level and before_exit()
3595 3595 // and VM_Exit op at VM level.
3596 3596 //
3597 3597 // Shutdown sequence:
3598 3598 // + Wait until we are the last non-daemon thread to execute
3599 3599 // <-- every thing is still working at this moment -->
3600 3600 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level
3601 3601 // shutdown hooks, run finalizers if finalization-on-exit
3602 3602 // + Call before_exit(), prepare for VM exit
3603 3603 // > run VM level shutdown hooks (they are registered through JVM_OnExit(),
3604 3604 // currently the only user of this mechanism is File.deleteOnExit())
3605 3605 // > stop flat profiler, StatSampler, watcher thread, CMS threads,
3606 3606 // post thread end and vm death events to JVMTI,
3607 3607 // stop signal thread
3608 3608 // + Call JavaThread::exit(), it will:
3609 3609 // > release JNI handle blocks, remove stack guard pages
3610 3610 // > remove this thread from Threads list
3611 3611 // <-- no more Java code from this thread after this point -->
3612 3612 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop
3613 3613 // the compiler threads at safepoint
3614 3614 // <-- do not use anything that could get blocked by Safepoint -->
3615 3615 // + Disable tracing at JNI/JVM barriers
3616 3616 // + Set _vm_exited flag for threads that are still running native code
3617 3617 // + Delete this thread
3618 3618 // + Call exit_globals()
3619 3619 // > deletes tty
3620 3620 // > deletes PerfMemory resources
3621 3621 // + Return to caller
3622 3622
3623 3623 bool Threads::destroy_vm() {
3624 3624 JavaThread* thread = JavaThread::current();
3625 3625
3626 3626 // Wait until we are the last non-daemon thread to execute
3627 3627 { MutexLocker nu(Threads_lock);
3628 3628 while (Threads::number_of_non_daemon_threads() > 1 )
3629 3629 // This wait should make safepoint checks, wait without a timeout,
3630 3630 // and wait as a suspend-equivalent condition.
3631 3631 //
3632 3632 // Note: If the FlatProfiler is running and this thread is waiting
3633 3633 // for another non-daemon thread to finish, then the FlatProfiler
3634 3634 // is waiting for the external suspend request on this thread to
3635 3635 // complete. wait_for_ext_suspend_completion() will eventually
3636 3636 // timeout, but that takes time. Making this wait a suspend-
3637 3637 // equivalent condition solves that timeout problem.
3638 3638 //
3639 3639 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
3640 3640 Mutex::_as_suspend_equivalent_flag);
3641 3641 }
3642 3642
3643 3643 // Hang forever on exit if we are reporting an error.
3644 3644 if (ShowMessageBoxOnError && is_error_reported()) {
3645 3645 os::infinite_sleep();
3646 3646 }
3647 3647 os::wait_for_keypress_at_exit();
3648 3648
3649 3649 if (JDK_Version::is_jdk12x_version()) {
3650 3650 // We are the last thread running, so check if finalizers should be run.
3651 3651 // For 1.3 or later this is done in thread->invoke_shutdown_hooks()
3652 3652 HandleMark rm(thread);
3653 3653 Universe::run_finalizers_on_exit();
3654 3654 } else {
3655 3655 // run Java level shutdown hooks
3656 3656 thread->invoke_shutdown_hooks();
3657 3657 }
3658 3658
3659 3659 before_exit(thread);
3660 3660
3661 3661 thread->exit(true);
3662 3662
3663 3663 // Stop VM thread.
3664 3664 {
3665 3665 // 4945125 The vm thread comes to a safepoint during exit.
3666 3666 // GC vm_operations can get caught at the safepoint, and the
3667 3667 // heap is unparseable if they are caught. Grab the Heap_lock
3668 3668 // to prevent this. The GC vm_operations will not be able to
3669 3669 // queue until after the vm thread is dead.
3670 3670 MutexLocker ml(Heap_lock);
3671 3671
3672 3672 VMThread::wait_for_vm_thread_exit();
3673 3673 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
3674 3674 VMThread::destroy();
3675 3675 }
3676 3676
3677 3677 // clean up ideal graph printers
3678 3678 #if defined(COMPILER2) && !defined(PRODUCT)
3679 3679 IdealGraphPrinter::clean_up();
3680 3680 #endif
3681 3681
3682 3682 // Now, all Java threads are gone except daemon threads. Daemon threads
3683 3683 // running Java code or in VM are stopped by the Safepoint. However,
3684 3684 // daemon threads executing native code are still running. But they
3685 3685 // will be stopped at native=>Java/VM barriers. Note that we can't
3686 3686 // simply kill or suspend them, as it is inherently deadlock-prone.
3687 3687
3688 3688 #ifndef PRODUCT
3689 3689 // disable function tracing at JNI/JVM barriers
3690 3690 TraceJNICalls = false;
3691 3691 TraceJVMCalls = false;
3692 3692 TraceRuntimeCalls = false;
3693 3693 #endif
3694 3694
3695 3695 VM_Exit::set_vm_exited();
3696 3696
3697 3697 notify_vm_shutdown();
3698 3698
3699 3699 delete thread;
3700 3700
3701 3701 // exit_globals() will delete tty
3702 3702 exit_globals();
3703 3703
3704 3704 return true;
3705 3705 }
3706 3706
3707 3707
3708 3708 jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
3709 3709 if (version == JNI_VERSION_1_1) return JNI_TRUE;
3710 3710 return is_supported_jni_version(version);
3711 3711 }
3712 3712
3713 3713
3714 3714 jboolean Threads::is_supported_jni_version(jint version) {
3715 3715 if (version == JNI_VERSION_1_2) return JNI_TRUE;
3716 3716 if (version == JNI_VERSION_1_4) return JNI_TRUE;
3717 3717 if (version == JNI_VERSION_1_6) return JNI_TRUE;
3718 3718 return JNI_FALSE;
3719 3719 }
3720 3720
3721 3721
3722 3722 void Threads::add(JavaThread* p, bool force_daemon) {
3723 3723 // The threads lock must be owned at this point
3724 3724 assert_locked_or_safepoint(Threads_lock);
3725 3725
3726 3726 // See the comment for this method in thread.hpp for its purpose and
3727 3727 // why it is called here.
3728 3728 p->initialize_queues();
3729 3729 p->set_next(_thread_list);
3730 3730 _thread_list = p;
3731 3731 _number_of_threads++;
3732 3732 oop threadObj = p->threadObj();
3733 3733 bool daemon = true;
3734 3734 // Bootstrapping problem: threadObj can be null for initial
3735 3735 // JavaThread (or for threads attached via JNI)
3736 3736 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
3737 3737 _number_of_non_daemon_threads++;
3738 3738 daemon = false;
3739 3739 }
3740 3740
3741 3741 ThreadService::add_thread(p, daemon);
3742 3742
3743 3743 // Possible GC point.
3744 3744 Events::log("Thread added: " INTPTR_FORMAT, p);
3745 3745 }
3746 3746
3747 3747 void Threads::remove(JavaThread* p) {
3748 3748 // Extra scope needed for Thread_lock, so we can check
3749 3749 // that we do not remove thread without safepoint code notice
3750 3750 { MutexLocker ml(Threads_lock);
3751 3751
3752 3752 assert(includes(p), "p must be present");
3753 3753
3754 3754 JavaThread* current = _thread_list;
3755 3755 JavaThread* prev = NULL;
3756 3756
3757 3757 while (current != p) {
3758 3758 prev = current;
3759 3759 current = current->next();
3760 3760 }
3761 3761
3762 3762 if (prev) {
3763 3763 prev->set_next(current->next());
3764 3764 } else {
3765 3765 _thread_list = p->next();
3766 3766 }
3767 3767 _number_of_threads--;
3768 3768 oop threadObj = p->threadObj();
3769 3769 bool daemon = true;
3770 3770 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
3771 3771 _number_of_non_daemon_threads--;
3772 3772 daemon = false;
3773 3773
3774 3774 // Only one thread left, do a notify on the Threads_lock so a thread waiting
3775 3775 // on destroy_vm will wake up.
3776 3776 if (number_of_non_daemon_threads() == 1)
3777 3777 Threads_lock->notify_all();
3778 3778 }
3779 3779 ThreadService::remove_thread(p, daemon);
3780 3780
3781 3781 // Make sure that safepoint code disregard this thread. This is needed since
3782 3782 // the thread might mess around with locks after this point. This can cause it
3783 3783 // to do callbacks into the safepoint code. However, the safepoint code is not aware
3784 3784 // of this thread since it is removed from the queue.
3785 3785 p->set_terminated_value();
3786 3786 } // unlock Threads_lock
3787 3787
3788 3788 // Since Events::log uses a lock, we grab it outside the Threads_lock
3789 3789 Events::log("Thread exited: " INTPTR_FORMAT, p);
3790 3790 }
3791 3791
3792 3792 // Threads_lock must be held when this is called (or must be called during a safepoint)
3793 3793 bool Threads::includes(JavaThread* p) {
3794 3794 assert(Threads_lock->is_locked(), "sanity check");
3795 3795 ALL_JAVA_THREADS(q) {
3796 3796 if (q == p ) {
3797 3797 return true;
3798 3798 }
3799 3799 }
3800 3800 return false;
3801 3801 }
3802 3802
3803 3803 // Operations on the Threads list for GC. These are not explicitly locked,
3804 3804 // but the garbage collector must provide a safe context for them to run.
3805 3805 // In particular, these things should never be called when the Threads_lock
3806 3806 // is held by some other thread. (Note: the Safepoint abstraction also
3807 3807 // uses the Threads_lock to gurantee this property. It also makes sure that
3808 3808 // all threads gets blocked when exiting or starting).
3809 3809
3810 3810 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
3811 3811 ALL_JAVA_THREADS(p) {
3812 3812 p->oops_do(f, cf);
3813 3813 }
3814 3814 VMThread::vm_thread()->oops_do(f, cf);
3815 3815 }
3816 3816
3817 3817 void Threads::possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf) {
3818 3818 // Introduce a mechanism allowing parallel threads to claim threads as
3819 3819 // root groups. Overhead should be small enough to use all the time,
3820 3820 // even in sequential code.
3821 3821 SharedHeap* sh = SharedHeap::heap();
3822 3822 bool is_par = (sh->n_par_threads() > 0);
3823 3823 int cp = SharedHeap::heap()->strong_roots_parity();
3824 3824 ALL_JAVA_THREADS(p) {
3825 3825 if (p->claim_oops_do(is_par, cp)) {
3826 3826 p->oops_do(f, cf);
3827 3827 }
3828 3828 }
3829 3829 VMThread* vmt = VMThread::vm_thread();
3830 3830 if (vmt->claim_oops_do(is_par, cp))
3831 3831 vmt->oops_do(f, cf);
3832 3832 }
3833 3833
3834 3834 #ifndef SERIALGC
3835 3835 // Used by ParallelScavenge
3836 3836 void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
3837 3837 ALL_JAVA_THREADS(p) {
3838 3838 q->enqueue(new ThreadRootsTask(p));
3839 3839 }
3840 3840 q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
3841 3841 }
3842 3842
3843 3843 // Used by Parallel Old
3844 3844 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
3845 3845 ALL_JAVA_THREADS(p) {
3846 3846 q->enqueue(new ThreadRootsMarkingTask(p));
3847 3847 }
3848 3848 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
3849 3849 }
3850 3850 #endif // SERIALGC
3851 3851
3852 3852 void Threads::nmethods_do(CodeBlobClosure* cf) {
3853 3853 ALL_JAVA_THREADS(p) {
3854 3854 p->nmethods_do(cf);
3855 3855 }
3856 3856 VMThread::vm_thread()->nmethods_do(cf);
3857 3857 }
3858 3858
3859 3859 void Threads::gc_epilogue() {
3860 3860 ALL_JAVA_THREADS(p) {
3861 3861 p->gc_epilogue();
3862 3862 }
3863 3863 }
3864 3864
3865 3865 void Threads::gc_prologue() {
3866 3866 ALL_JAVA_THREADS(p) {
3867 3867 p->gc_prologue();
3868 3868 }
3869 3869 }
3870 3870
3871 3871 void Threads::deoptimized_wrt_marked_nmethods() {
3872 3872 ALL_JAVA_THREADS(p) {
3873 3873 p->deoptimized_wrt_marked_nmethods();
3874 3874 }
3875 3875 }
3876 3876
3877 3877
3878 3878 // Get count Java threads that are waiting to enter the specified monitor.
3879 3879 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
3880 3880 address monitor, bool doLock) {
3881 3881 assert(doLock || SafepointSynchronize::is_at_safepoint(),
3882 3882 "must grab Threads_lock or be at safepoint");
3883 3883 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
3884 3884
3885 3885 int i = 0;
3886 3886 {
3887 3887 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3888 3888 ALL_JAVA_THREADS(p) {
3889 3889 if (p->is_Compiler_thread()) continue;
3890 3890
3891 3891 address pending = (address)p->current_pending_monitor();
3892 3892 if (pending == monitor) { // found a match
3893 3893 if (i < count) result->append(p); // save the first count matches
3894 3894 i++;
3895 3895 }
3896 3896 }
3897 3897 }
3898 3898 return result;
3899 3899 }
3900 3900
3901 3901
3902 3902 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) {
3903 3903 assert(doLock ||
3904 3904 Threads_lock->owned_by_self() ||
3905 3905 SafepointSynchronize::is_at_safepoint(),
3906 3906 "must grab Threads_lock or be at safepoint");
3907 3907
3908 3908 // NULL owner means not locked so we can skip the search
3909 3909 if (owner == NULL) return NULL;
3910 3910
3911 3911 {
3912 3912 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3913 3913 ALL_JAVA_THREADS(p) {
3914 3914 // first, see if owner is the address of a Java thread
3915 3915 if (owner == (address)p) return p;
3916 3916 }
3917 3917 }
3918 3918 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled");
3919 3919 if (UseHeavyMonitors) return NULL;
3920 3920
3921 3921 //
3922 3922 // If we didn't find a matching Java thread and we didn't force use of
3923 3923 // heavyweight monitors, then the owner is the stack address of the
3924 3924 // Lock Word in the owning Java thread's stack.
3925 3925 //
3926 3926 JavaThread* the_owner = NULL;
3927 3927 {
3928 3928 MutexLockerEx ml(doLock ? Threads_lock : NULL);
3929 3929 ALL_JAVA_THREADS(q) {
3930 3930 if (q->is_lock_owned(owner)) {
3931 3931 the_owner = q;
3932 3932 break;
3933 3933 }
3934 3934 }
3935 3935 }
3936 3936 assert(the_owner != NULL, "Did not find owning Java thread for lock word address");
3937 3937 return the_owner;
3938 3938 }
3939 3939
3940 3940 // Threads::print_on() is called at safepoint by VM_PrintThreads operation.
3941 3941 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) {
3942 3942 char buf[32];
3943 3943 st->print_cr(os::local_time_string(buf, sizeof(buf)));
3944 3944
3945 3945 st->print_cr("Full thread dump %s (%s %s):",
3946 3946 Abstract_VM_Version::vm_name(),
3947 3947 Abstract_VM_Version::vm_release(),
3948 3948 Abstract_VM_Version::vm_info_string()
3949 3949 );
3950 3950 st->cr();
3951 3951
3952 3952 #ifndef SERIALGC
3953 3953 // Dump concurrent locks
3954 3954 ConcurrentLocksDump concurrent_locks;
3955 3955 if (print_concurrent_locks) {
3956 3956 concurrent_locks.dump_at_safepoint();
3957 3957 }
3958 3958 #endif // SERIALGC
3959 3959
3960 3960 ALL_JAVA_THREADS(p) {
3961 3961 ResourceMark rm;
3962 3962 p->print_on(st);
3963 3963 if (print_stacks) {
3964 3964 if (internal_format) {
3965 3965 p->trace_stack();
3966 3966 } else {
3967 3967 p->print_stack_on(st);
3968 3968 }
3969 3969 }
3970 3970 st->cr();
3971 3971 #ifndef SERIALGC
3972 3972 if (print_concurrent_locks) {
3973 3973 concurrent_locks.print_locks_on(p, st);
3974 3974 }
3975 3975 #endif // SERIALGC
3976 3976 }
3977 3977
3978 3978 VMThread::vm_thread()->print_on(st);
3979 3979 st->cr();
3980 3980 Universe::heap()->print_gc_threads_on(st);
3981 3981 WatcherThread* wt = WatcherThread::watcher_thread();
3982 3982 if (wt != NULL) wt->print_on(st);
3983 3983 st->cr();
3984 3984 CompileBroker::print_compiler_threads_on(st);
3985 3985 st->flush();
3986 3986 }
3987 3987
3988 3988 // Threads::print_on_error() is called by fatal error handler. It's possible
3989 3989 // that VM is not at safepoint and/or current thread is inside signal handler.
3990 3990 // Don't print stack trace, as the stack may not be walkable. Don't allocate
3991 3991 // memory (even in resource area), it might deadlock the error handler.
3992 3992 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) {
3993 3993 bool found_current = false;
3994 3994 st->print_cr("Java Threads: ( => current thread )");
3995 3995 ALL_JAVA_THREADS(thread) {
3996 3996 bool is_current = (current == thread);
3997 3997 found_current = found_current || is_current;
3998 3998
3999 3999 st->print("%s", is_current ? "=>" : " ");
4000 4000
4001 4001 st->print(PTR_FORMAT, thread);
4002 4002 st->print(" ");
4003 4003 thread->print_on_error(st, buf, buflen);
4004 4004 st->cr();
4005 4005 }
4006 4006 st->cr();
4007 4007
4008 4008 st->print_cr("Other Threads:");
4009 4009 if (VMThread::vm_thread()) {
4010 4010 bool is_current = (current == VMThread::vm_thread());
4011 4011 found_current = found_current || is_current;
4012 4012 st->print("%s", current == VMThread::vm_thread() ? "=>" : " ");
4013 4013
4014 4014 st->print(PTR_FORMAT, VMThread::vm_thread());
4015 4015 st->print(" ");
4016 4016 VMThread::vm_thread()->print_on_error(st, buf, buflen);
4017 4017 st->cr();
4018 4018 }
4019 4019 WatcherThread* wt = WatcherThread::watcher_thread();
4020 4020 if (wt != NULL) {
4021 4021 bool is_current = (current == wt);
4022 4022 found_current = found_current || is_current;
4023 4023 st->print("%s", is_current ? "=>" : " ");
4024 4024
4025 4025 st->print(PTR_FORMAT, wt);
4026 4026 st->print(" ");
4027 4027 wt->print_on_error(st, buf, buflen);
4028 4028 st->cr();
4029 4029 }
4030 4030 if (!found_current) {
4031 4031 st->cr();
4032 4032 st->print("=>" PTR_FORMAT " (exited) ", current);
4033 4033 current->print_on_error(st, buf, buflen);
4034 4034 st->cr();
4035 4035 }
4036 4036 }
4037 4037
4038 4038 // Internal SpinLock and Mutex
4039 4039 // Based on ParkEvent
4040 4040
4041 4041 // Ad-hoc mutual exclusion primitives: SpinLock and Mux
4042 4042 //
4043 4043 // We employ SpinLocks _only for low-contention, fixed-length
4044 4044 // short-duration critical sections where we're concerned
4045 4045 // about native mutex_t or HotSpot Mutex:: latency.
4046 4046 // The mux construct provides a spin-then-block mutual exclusion
4047 4047 // mechanism.
4048 4048 //
4049 4049 // Testing has shown that contention on the ListLock guarding gFreeList
4050 4050 // is common. If we implement ListLock as a simple SpinLock it's common
4051 4051 // for the JVM to devolve to yielding with little progress. This is true
4052 4052 // despite the fact that the critical sections protected by ListLock are
4053 4053 // extremely short.
4054 4054 //
4055 4055 // TODO-FIXME: ListLock should be of type SpinLock.
4056 4056 // We should make this a 1st-class type, integrated into the lock
4057 4057 // hierarchy as leaf-locks. Critically, the SpinLock structure
4058 4058 // should have sufficient padding to avoid false-sharing and excessive
4059 4059 // cache-coherency traffic.
4060 4060
4061 4061
4062 4062 typedef volatile int SpinLockT ;
4063 4063
4064 4064 void Thread::SpinAcquire (volatile int * adr, const char * LockName) {
4065 4065 if (Atomic::cmpxchg (1, adr, 0) == 0) {
4066 4066 return ; // normal fast-path return
4067 4067 }
4068 4068
4069 4069 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
4070 4070 TEVENT (SpinAcquire - ctx) ;
4071 4071 int ctr = 0 ;
4072 4072 int Yields = 0 ;
4073 4073 for (;;) {
4074 4074 while (*adr != 0) {
4075 4075 ++ctr ;
4076 4076 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
4077 4077 if (Yields > 5) {
4078 4078 // Consider using a simple NakedSleep() instead.
4079 4079 // Then SpinAcquire could be called by non-JVM threads
4080 4080 Thread::current()->_ParkEvent->park(1) ;
4081 4081 } else {
4082 4082 os::NakedYield() ;
4083 4083 ++Yields ;
4084 4084 }
4085 4085 } else {
4086 4086 SpinPause() ;
4087 4087 }
4088 4088 }
4089 4089 if (Atomic::cmpxchg (1, adr, 0) == 0) return ;
4090 4090 }
4091 4091 }
4092 4092
4093 4093 void Thread::SpinRelease (volatile int * adr) {
4094 4094 assert (*adr != 0, "invariant") ;
4095 4095 OrderAccess::fence() ; // guarantee at least release consistency.
4096 4096 // Roach-motel semantics.
4097 4097 // It's safe if subsequent LDs and STs float "up" into the critical section,
4098 4098 // but prior LDs and STs within the critical section can't be allowed
4099 4099 // to reorder or float past the ST that releases the lock.
4100 4100 *adr = 0 ;
4101 4101 }
4102 4102
4103 4103 // muxAcquire and muxRelease:
4104 4104 //
4105 4105 // * muxAcquire and muxRelease support a single-word lock-word construct.
4106 4106 // The LSB of the word is set IFF the lock is held.
4107 4107 // The remainder of the word points to the head of a singly-linked list
4108 4108 // of threads blocked on the lock.
4109 4109 //
4110 4110 // * The current implementation of muxAcquire-muxRelease uses its own
4111 4111 // dedicated Thread._MuxEvent instance. If we're interested in
4112 4112 // minimizing the peak number of extant ParkEvent instances then
4113 4113 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long
4114 4114 // as certain invariants were satisfied. Specifically, care would need
4115 4115 // to be taken with regards to consuming unpark() "permits".
4116 4116 // A safe rule of thumb is that a thread would never call muxAcquire()
4117 4117 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
4118 4118 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could
4119 4119 // consume an unpark() permit intended for monitorenter, for instance.
4120 4120 // One way around this would be to widen the restricted-range semaphore
4121 4121 // implemented in park(). Another alternative would be to provide
4122 4122 // multiple instances of the PlatformEvent() for each thread. One
4123 4123 // instance would be dedicated to muxAcquire-muxRelease, for instance.
4124 4124 //
4125 4125 // * Usage:
4126 4126 // -- Only as leaf locks
4127 4127 // -- for short-term locking only as muxAcquire does not perform
4128 4128 // thread state transitions.
4129 4129 //
4130 4130 // Alternatives:
4131 4131 // * We could implement muxAcquire and muxRelease with MCS or CLH locks
4132 4132 // but with parking or spin-then-park instead of pure spinning.
4133 4133 // * Use Taura-Oyama-Yonenzawa locks.
4134 4134 // * It's possible to construct a 1-0 lock if we encode the lockword as
4135 4135 // (List,LockByte). Acquire will CAS the full lockword while Release
4136 4136 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so
4137 4137 // acquiring threads use timers (ParkTimed) to detect and recover from
4138 4138 // the stranding window. Thread/Node structures must be aligned on 256-byte
4139 4139 // boundaries by using placement-new.
4140 4140 // * Augment MCS with advisory back-link fields maintained with CAS().
4141 4141 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
4142 4142 // The validity of the backlinks must be ratified before we trust the value.
4143 4143 // If the backlinks are invalid the exiting thread must back-track through the
4144 4144 // the forward links, which are always trustworthy.
4145 4145 // * Add a successor indication. The LockWord is currently encoded as
4146 4146 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable
4147 4147 // to provide the usual futile-wakeup optimization.
4148 4148 // See RTStt for details.
4149 4149 // * Consider schedctl.sc_nopreempt to cover the critical section.
4150 4150 //
4151 4151
4152 4152
4153 4153 typedef volatile intptr_t MutexT ; // Mux Lock-word
4154 4154 enum MuxBits { LOCKBIT = 1 } ;
4155 4155
4156 4156 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) {
4157 4157 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4158 4158 if (w == 0) return ;
4159 4159 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4160 4160 return ;
4161 4161 }
4162 4162
4163 4163 TEVENT (muxAcquire - Contention) ;
4164 4164 ParkEvent * const Self = Thread::current()->_MuxEvent ;
4165 4165 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ;
4166 4166 for (;;) {
4167 4167 int its = (os::is_MP() ? 100 : 0) + 1 ;
4168 4168
4169 4169 // Optional spin phase: spin-then-park strategy
4170 4170 while (--its >= 0) {
4171 4171 w = *Lock ;
4172 4172 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4173 4173 return ;
4174 4174 }
4175 4175 }
4176 4176
4177 4177 Self->reset() ;
4178 4178 Self->OnList = intptr_t(Lock) ;
4179 4179 // The following fence() isn't _strictly necessary as the subsequent
4180 4180 // CAS() both serializes execution and ratifies the fetched *Lock value.
4181 4181 OrderAccess::fence();
4182 4182 for (;;) {
4183 4183 w = *Lock ;
4184 4184 if ((w & LOCKBIT) == 0) {
4185 4185 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4186 4186 Self->OnList = 0 ; // hygiene - allows stronger asserts
4187 4187 return ;
4188 4188 }
4189 4189 continue ; // Interference -- *Lock changed -- Just retry
4190 4190 }
4191 4191 assert (w & LOCKBIT, "invariant") ;
4192 4192 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4193 4193 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ;
4194 4194 }
4195 4195
4196 4196 while (Self->OnList != 0) {
4197 4197 Self->park() ;
4198 4198 }
4199 4199 }
4200 4200 }
4201 4201
4202 4202 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) {
4203 4203 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ;
4204 4204 if (w == 0) return ;
4205 4205 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4206 4206 return ;
4207 4207 }
4208 4208
4209 4209 TEVENT (muxAcquire - Contention) ;
4210 4210 ParkEvent * ReleaseAfter = NULL ;
4211 4211 if (ev == NULL) {
4212 4212 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ;
4213 4213 }
4214 4214 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ;
4215 4215 for (;;) {
4216 4216 guarantee (ev->OnList == 0, "invariant") ;
4217 4217 int its = (os::is_MP() ? 100 : 0) + 1 ;
4218 4218
4219 4219 // Optional spin phase: spin-then-park strategy
4220 4220 while (--its >= 0) {
4221 4221 w = *Lock ;
4222 4222 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4223 4223 if (ReleaseAfter != NULL) {
4224 4224 ParkEvent::Release (ReleaseAfter) ;
4225 4225 }
4226 4226 return ;
4227 4227 }
4228 4228 }
4229 4229
4230 4230 ev->reset() ;
4231 4231 ev->OnList = intptr_t(Lock) ;
4232 4232 // The following fence() isn't _strictly necessary as the subsequent
4233 4233 // CAS() both serializes execution and ratifies the fetched *Lock value.
4234 4234 OrderAccess::fence();
4235 4235 for (;;) {
4236 4236 w = *Lock ;
4237 4237 if ((w & LOCKBIT) == 0) {
4238 4238 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
4239 4239 ev->OnList = 0 ;
4240 4240 // We call ::Release while holding the outer lock, thus
4241 4241 // artificially lengthening the critical section.
4242 4242 // Consider deferring the ::Release() until the subsequent unlock(),
4243 4243 // after we've dropped the outer lock.
4244 4244 if (ReleaseAfter != NULL) {
4245 4245 ParkEvent::Release (ReleaseAfter) ;
4246 4246 }
4247 4247 return ;
4248 4248 }
4249 4249 continue ; // Interference -- *Lock changed -- Just retry
4250 4250 }
4251 4251 assert (w & LOCKBIT, "invariant") ;
4252 4252 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT );
4253 4253 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ;
4254 4254 }
4255 4255
4256 4256 while (ev->OnList != 0) {
4257 4257 ev->park() ;
4258 4258 }
4259 4259 }
4260 4260 }
4261 4261
4262 4262 // Release() must extract a successor from the list and then wake that thread.
4263 4263 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
4264 4264 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based
4265 4265 // Release() would :
4266 4266 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
4267 4267 // (B) Extract a successor from the private list "in-hand"
4268 4268 // (C) attempt to CAS() the residual back into *Lock over null.
4269 4269 // If there were any newly arrived threads and the CAS() would fail.
4270 4270 // In that case Release() would detach the RATs, re-merge the list in-hand
4271 4271 // with the RATs and repeat as needed. Alternately, Release() might
4272 4272 // detach and extract a successor, but then pass the residual list to the wakee.
4273 4273 // The wakee would be responsible for reattaching and remerging before it
4274 4274 // competed for the lock.
4275 4275 //
4276 4276 // Both "pop" and DMR are immune from ABA corruption -- there can be
4277 4277 // multiple concurrent pushers, but only one popper or detacher.
4278 4278 // This implementation pops from the head of the list. This is unfair,
4279 4279 // but tends to provide excellent throughput as hot threads remain hot.
4280 4280 // (We wake recently run threads first).
4281 4281
4282 4282 void Thread::muxRelease (volatile intptr_t * Lock) {
4283 4283 for (;;) {
4284 4284 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ;
4285 4285 assert (w & LOCKBIT, "invariant") ;
4286 4286 if (w == LOCKBIT) return ;
4287 4287 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ;
4288 4288 assert (List != NULL, "invariant") ;
4289 4289 assert (List->OnList == intptr_t(Lock), "invariant") ;
4290 4290 ParkEvent * nxt = List->ListNext ;
4291 4291
4292 4292 // The following CAS() releases the lock and pops the head element.
4293 4293 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
4294 4294 continue ;
4295 4295 }
4296 4296 List->OnList = 0 ;
4297 4297 OrderAccess::fence() ;
4298 4298 List->unpark () ;
4299 4299 return ;
4300 4300 }
4301 4301 }
4302 4302
4303 4303
4304 4304 void Threads::verify() {
4305 4305 ALL_JAVA_THREADS(p) {
4306 4306 p->verify();
4307 4307 }
4308 4308 VMThread* thread = VMThread::vm_thread();
4309 4309 if (thread != NULL) thread->verify();
4310 4310 }
|
↓ open down ↓ |
1068 lines elided |
↑ open up ↑ |
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX