1 /* 2 * Copyright 1997-2009 Sun Microsystems, Inc. All Rights Reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20 * CA 95054 USA or visit www.sun.com if you need additional information or 21 * have any questions. 22 * 23 */ 24 25 # include "incls/_precompiled.incl" 26 # include "incls/_thread.cpp.incl" 27 28 #ifdef DTRACE_ENABLED 29 30 // Only bother with this argument setup if dtrace is available 31 32 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin); 33 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end); 34 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t, 35 intptr_t, intptr_t, bool); 36 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t, 37 intptr_t, intptr_t, bool); 38 39 #define DTRACE_THREAD_PROBE(probe, javathread) \ 40 { \ 41 ResourceMark rm(this); \ 42 int len = 0; \ 43 const char* name = (javathread)->get_thread_name(); \ 44 len = strlen(name); \ 45 HS_DTRACE_PROBE5(hotspot, thread__##probe, \ 46 name, len, \ 47 java_lang_Thread::thread_id((javathread)->threadObj()), \ 48 (javathread)->osthread()->thread_id(), \ 49 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 50 } 51 52 #else // ndef DTRACE_ENABLED 53 54 #define DTRACE_THREAD_PROBE(probe, javathread) 55 56 #endif // ndef DTRACE_ENABLED 57 58 // Class hierarchy 59 // - Thread 60 // - VMThread 61 // - WatcherThread 62 // - ConcurrentMarkSweepThread 63 // - JavaThread 64 // - CompilerThread 65 66 // ======= Thread ======== 67 68 // Support for forcing alignment of thread objects for biased locking 69 void* Thread::operator new(size_t size) { 70 if (UseBiasedLocking) { 71 const int alignment = markOopDesc::biased_lock_alignment; 72 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 73 void* real_malloc_addr = CHeapObj::operator new(aligned_size); 74 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 75 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 76 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 77 "JavaThread alignment code overflowed allocated storage"); 78 if (TraceBiasedLocking) { 79 if (aligned_addr != real_malloc_addr) 80 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 81 real_malloc_addr, aligned_addr); 82 } 83 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 84 return aligned_addr; 85 } else { 86 return CHeapObj::operator new(size); 87 } 88 } 89 90 void Thread::operator delete(void* p) { 91 if (UseBiasedLocking) { 92 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 93 CHeapObj::operator delete(real_malloc_addr); 94 } else { 95 CHeapObj::operator delete(p); 96 } 97 } 98 99 100 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 101 // JavaThread 102 103 104 Thread::Thread() { 105 // stack 106 _stack_base = NULL; 107 _stack_size = 0; 108 _self_raw_id = 0; 109 _lgrp_id = -1; 110 _osthread = NULL; 111 112 // allocated data structures 113 set_resource_area(new ResourceArea()); 114 set_handle_area(new HandleArea(NULL)); 115 set_active_handles(NULL); 116 set_free_handle_block(NULL); 117 set_last_handle_mark(NULL); 118 set_osthread(NULL); 119 120 // This initial value ==> never claimed. 121 _oops_do_parity = 0; 122 123 // the handle mark links itself to last_handle_mark 124 new HandleMark(this); 125 126 // plain initialization 127 debug_only(_owned_locks = NULL;) 128 debug_only(_allow_allocation_count = 0;) 129 NOT_PRODUCT(_allow_safepoint_count = 0;) 130 NOT_PRODUCT(_skip_gcalot = false;) 131 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;) 132 _jvmti_env_iteration_count = 0; 133 _vm_operation_started_count = 0; 134 _vm_operation_completed_count = 0; 135 _current_pending_monitor = NULL; 136 _current_pending_monitor_is_from_java = true; 137 _current_waiting_monitor = NULL; 138 _num_nested_signal = 0; 139 omFreeList = NULL ; 140 omFreeCount = 0 ; 141 omFreeProvision = 32 ; 142 143 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true); 144 _suspend_flags = 0; 145 146 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 147 _hashStateX = os::random() ; 148 _hashStateY = 842502087 ; 149 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ; 150 _hashStateW = 273326509 ; 151 152 _OnTrap = 0 ; 153 _schedctl = NULL ; 154 _Stalled = 0 ; 155 _TypeTag = 0x2BAD ; 156 157 // Many of the following fields are effectively final - immutable 158 // Note that nascent threads can't use the Native Monitor-Mutex 159 // construct until the _MutexEvent is initialized ... 160 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 161 // we might instead use a stack of ParkEvents that we could provision on-demand. 162 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 163 // and ::Release() 164 _ParkEvent = ParkEvent::Allocate (this) ; 165 _SleepEvent = ParkEvent::Allocate (this) ; 166 _MutexEvent = ParkEvent::Allocate (this) ; 167 _MuxEvent = ParkEvent::Allocate (this) ; 168 169 #ifdef CHECK_UNHANDLED_OOPS 170 if (CheckUnhandledOops) { 171 _unhandled_oops = new UnhandledOops(this); 172 } 173 #endif // CHECK_UNHANDLED_OOPS 174 #ifdef ASSERT 175 if (UseBiasedLocking) { 176 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 177 assert(this == _real_malloc_address || 178 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 179 "bug in forced alignment of thread objects"); 180 } 181 #endif /* ASSERT */ 182 } 183 184 void Thread::initialize_thread_local_storage() { 185 // Note: Make sure this method only calls 186 // non-blocking operations. Otherwise, it might not work 187 // with the thread-startup/safepoint interaction. 188 189 // During Java thread startup, safepoint code should allow this 190 // method to complete because it may need to allocate memory to 191 // store information for the new thread. 192 193 // initialize structure dependent on thread local storage 194 ThreadLocalStorage::set_thread(this); 195 196 // set up any platform-specific state. 197 os::initialize_thread(); 198 199 } 200 201 void Thread::record_stack_base_and_size() { 202 set_stack_base(os::current_stack_base()); 203 set_stack_size(os::current_stack_size()); 204 } 205 206 207 Thread::~Thread() { 208 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 209 ObjectSynchronizer::omFlush (this) ; 210 211 // deallocate data structures 212 delete resource_area(); 213 // since the handle marks are using the handle area, we have to deallocated the root 214 // handle mark before deallocating the thread's handle area, 215 assert(last_handle_mark() != NULL, "check we have an element"); 216 delete last_handle_mark(); 217 assert(last_handle_mark() == NULL, "check we have reached the end"); 218 219 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 220 // We NULL out the fields for good hygiene. 221 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ; 222 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ; 223 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ; 224 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ; 225 226 delete handle_area(); 227 228 // osthread() can be NULL, if creation of thread failed. 229 if (osthread() != NULL) os::free_thread(osthread()); 230 231 delete _SR_lock; 232 233 // clear thread local storage if the Thread is deleting itself 234 if (this == Thread::current()) { 235 ThreadLocalStorage::set_thread(NULL); 236 } else { 237 // In the case where we're not the current thread, invalidate all the 238 // caches in case some code tries to get the current thread or the 239 // thread that was destroyed, and gets stale information. 240 ThreadLocalStorage::invalidate_all(); 241 } 242 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 243 } 244 245 // NOTE: dummy function for assertion purpose. 246 void Thread::run() { 247 ShouldNotReachHere(); 248 } 249 250 #ifdef ASSERT 251 // Private method to check for dangling thread pointer 252 void check_for_dangling_thread_pointer(Thread *thread) { 253 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 254 "possibility of dangling Thread pointer"); 255 } 256 #endif 257 258 259 #ifndef PRODUCT 260 // Tracing method for basic thread operations 261 void Thread::trace(const char* msg, const Thread* const thread) { 262 if (!TraceThreadEvents) return; 263 ResourceMark rm; 264 ThreadCritical tc; 265 const char *name = "non-Java thread"; 266 int prio = -1; 267 if (thread->is_Java_thread() 268 && !thread->is_Compiler_thread()) { 269 // The Threads_lock must be held to get information about 270 // this thread but may not be in some situations when 271 // tracing thread events. 272 bool release_Threads_lock = false; 273 if (!Threads_lock->owned_by_self()) { 274 Threads_lock->lock(); 275 release_Threads_lock = true; 276 } 277 JavaThread* jt = (JavaThread *)thread; 278 name = (char *)jt->get_thread_name(); 279 oop thread_oop = jt->threadObj(); 280 if (thread_oop != NULL) { 281 prio = java_lang_Thread::priority(thread_oop); 282 } 283 if (release_Threads_lock) { 284 Threads_lock->unlock(); 285 } 286 } 287 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); 288 } 289 #endif 290 291 292 ThreadPriority Thread::get_priority(const Thread* const thread) { 293 trace("get priority", thread); 294 ThreadPriority priority; 295 // Can return an error! 296 (void)os::get_priority(thread, priority); 297 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 298 return priority; 299 } 300 301 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 302 trace("set priority", thread); 303 debug_only(check_for_dangling_thread_pointer(thread);) 304 // Can return an error! 305 (void)os::set_priority(thread, priority); 306 } 307 308 309 void Thread::start(Thread* thread) { 310 trace("start", thread); 311 // Start is different from resume in that its safety is guaranteed by context or 312 // being called from a Java method synchronized on the Thread object. 313 if (!DisableStartThread) { 314 if (thread->is_Java_thread()) { 315 // Initialize the thread state to RUNNABLE before starting this thread. 316 // Can not set it after the thread started because we do not know the 317 // exact thread state at that time. It could be in MONITOR_WAIT or 318 // in SLEEPING or some other state. 319 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 320 java_lang_Thread::RUNNABLE); 321 } 322 os::start_thread(thread); 323 } 324 } 325 326 // Enqueue a VM_Operation to do the job for us - sometime later 327 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 328 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 329 VMThread::execute(vm_stop); 330 } 331 332 333 // 334 // Check if an external suspend request has completed (or has been 335 // cancelled). Returns true if the thread is externally suspended and 336 // false otherwise. 337 // 338 // The bits parameter returns information about the code path through 339 // the routine. Useful for debugging: 340 // 341 // set in is_ext_suspend_completed(): 342 // 0x00000001 - routine was entered 343 // 0x00000010 - routine return false at end 344 // 0x00000100 - thread exited (return false) 345 // 0x00000200 - suspend request cancelled (return false) 346 // 0x00000400 - thread suspended (return true) 347 // 0x00001000 - thread is in a suspend equivalent state (return true) 348 // 0x00002000 - thread is native and walkable (return true) 349 // 0x00004000 - thread is native_trans and walkable (needed retry) 350 // 351 // set in wait_for_ext_suspend_completion(): 352 // 0x00010000 - routine was entered 353 // 0x00020000 - suspend request cancelled before loop (return false) 354 // 0x00040000 - thread suspended before loop (return true) 355 // 0x00080000 - suspend request cancelled in loop (return false) 356 // 0x00100000 - thread suspended in loop (return true) 357 // 0x00200000 - suspend not completed during retry loop (return false) 358 // 359 360 // Helper class for tracing suspend wait debug bits. 361 // 362 // 0x00000100 indicates that the target thread exited before it could 363 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 364 // 0x00080000 each indicate a cancelled suspend request so they don't 365 // count as wait failures either. 366 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 367 368 class TraceSuspendDebugBits : public StackObj { 369 private: 370 JavaThread * jt; 371 bool is_wait; 372 bool called_by_wait; // meaningful when !is_wait 373 uint32_t * bits; 374 375 public: 376 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 377 uint32_t *_bits) { 378 jt = _jt; 379 is_wait = _is_wait; 380 called_by_wait = _called_by_wait; 381 bits = _bits; 382 } 383 384 ~TraceSuspendDebugBits() { 385 if (!is_wait) { 386 #if 1 387 // By default, don't trace bits for is_ext_suspend_completed() calls. 388 // That trace is very chatty. 389 return; 390 #else 391 if (!called_by_wait) { 392 // If tracing for is_ext_suspend_completed() is enabled, then only 393 // trace calls to it from wait_for_ext_suspend_completion() 394 return; 395 } 396 #endif 397 } 398 399 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 400 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 401 MutexLocker ml(Threads_lock); // needed for get_thread_name() 402 ResourceMark rm; 403 404 tty->print_cr( 405 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 406 jt->get_thread_name(), *bits); 407 408 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 409 } 410 } 411 } 412 }; 413 #undef DEBUG_FALSE_BITS 414 415 416 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) { 417 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 418 419 bool did_trans_retry = false; // only do thread_in_native_trans retry once 420 bool do_trans_retry; // flag to force the retry 421 422 *bits |= 0x00000001; 423 424 do { 425 do_trans_retry = false; 426 427 if (is_exiting()) { 428 // Thread is in the process of exiting. This is always checked 429 // first to reduce the risk of dereferencing a freed JavaThread. 430 *bits |= 0x00000100; 431 return false; 432 } 433 434 if (!is_external_suspend()) { 435 // Suspend request is cancelled. This is always checked before 436 // is_ext_suspended() to reduce the risk of a rogue resume 437 // confusing the thread that made the suspend request. 438 *bits |= 0x00000200; 439 return false; 440 } 441 442 if (is_ext_suspended()) { 443 // thread is suspended 444 *bits |= 0x00000400; 445 return true; 446 } 447 448 // Now that we no longer do hard suspends of threads running 449 // native code, the target thread can be changing thread state 450 // while we are in this routine: 451 // 452 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 453 // 454 // We save a copy of the thread state as observed at this moment 455 // and make our decision about suspend completeness based on the 456 // copy. This closes the race where the thread state is seen as 457 // _thread_in_native_trans in the if-thread_blocked check, but is 458 // seen as _thread_blocked in if-thread_in_native_trans check. 459 JavaThreadState save_state = thread_state(); 460 461 if (save_state == _thread_blocked && is_suspend_equivalent()) { 462 // If the thread's state is _thread_blocked and this blocking 463 // condition is known to be equivalent to a suspend, then we can 464 // consider the thread to be externally suspended. This means that 465 // the code that sets _thread_blocked has been modified to do 466 // self-suspension if the blocking condition releases. We also 467 // used to check for CONDVAR_WAIT here, but that is now covered by 468 // the _thread_blocked with self-suspension check. 469 // 470 // Return true since we wouldn't be here unless there was still an 471 // external suspend request. 472 *bits |= 0x00001000; 473 return true; 474 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 475 // Threads running native code will self-suspend on native==>VM/Java 476 // transitions. If its stack is walkable (should always be the case 477 // unless this function is called before the actual java_suspend() 478 // call), then the wait is done. 479 *bits |= 0x00002000; 480 return true; 481 } else if (!called_by_wait && !did_trans_retry && 482 save_state == _thread_in_native_trans && 483 frame_anchor()->walkable()) { 484 // The thread is transitioning from thread_in_native to another 485 // thread state. check_safepoint_and_suspend_for_native_trans() 486 // will force the thread to self-suspend. If it hasn't gotten 487 // there yet we may have caught the thread in-between the native 488 // code check above and the self-suspend. Lucky us. If we were 489 // called by wait_for_ext_suspend_completion(), then it 490 // will be doing the retries so we don't have to. 491 // 492 // Since we use the saved thread state in the if-statement above, 493 // there is a chance that the thread has already transitioned to 494 // _thread_blocked by the time we get here. In that case, we will 495 // make a single unnecessary pass through the logic below. This 496 // doesn't hurt anything since we still do the trans retry. 497 498 *bits |= 0x00004000; 499 500 // Once the thread leaves thread_in_native_trans for another 501 // thread state, we break out of this retry loop. We shouldn't 502 // need this flag to prevent us from getting back here, but 503 // sometimes paranoia is good. 504 did_trans_retry = true; 505 506 // We wait for the thread to transition to a more usable state. 507 for (int i = 1; i <= SuspendRetryCount; i++) { 508 // We used to do an "os::yield_all(i)" call here with the intention 509 // that yielding would increase on each retry. However, the parameter 510 // is ignored on Linux which means the yield didn't scale up. Waiting 511 // on the SR_lock below provides a much more predictable scale up for 512 // the delay. It also provides a simple/direct point to check for any 513 // safepoint requests from the VMThread 514 515 // temporarily drops SR_lock while doing wait with safepoint check 516 // (if we're a JavaThread - the WatcherThread can also call this) 517 // and increase delay with each retry 518 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 519 520 // check the actual thread state instead of what we saved above 521 if (thread_state() != _thread_in_native_trans) { 522 // the thread has transitioned to another thread state so 523 // try all the checks (except this one) one more time. 524 do_trans_retry = true; 525 break; 526 } 527 } // end retry loop 528 529 530 } 531 } while (do_trans_retry); 532 533 *bits |= 0x00000010; 534 return false; 535 } 536 537 // 538 // Wait for an external suspend request to complete (or be cancelled). 539 // Returns true if the thread is externally suspended and false otherwise. 540 // 541 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 542 uint32_t *bits) { 543 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 544 false /* !called_by_wait */, bits); 545 546 // local flag copies to minimize SR_lock hold time 547 bool is_suspended; 548 bool pending; 549 uint32_t reset_bits; 550 551 // set a marker so is_ext_suspend_completed() knows we are the caller 552 *bits |= 0x00010000; 553 554 // We use reset_bits to reinitialize the bits value at the top of 555 // each retry loop. This allows the caller to make use of any 556 // unused bits for their own marking purposes. 557 reset_bits = *bits; 558 559 { 560 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 561 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 562 delay, bits); 563 pending = is_external_suspend(); 564 } 565 // must release SR_lock to allow suspension to complete 566 567 if (!pending) { 568 // A cancelled suspend request is the only false return from 569 // is_ext_suspend_completed() that keeps us from entering the 570 // retry loop. 571 *bits |= 0x00020000; 572 return false; 573 } 574 575 if (is_suspended) { 576 *bits |= 0x00040000; 577 return true; 578 } 579 580 for (int i = 1; i <= retries; i++) { 581 *bits = reset_bits; // reinit to only track last retry 582 583 // We used to do an "os::yield_all(i)" call here with the intention 584 // that yielding would increase on each retry. However, the parameter 585 // is ignored on Linux which means the yield didn't scale up. Waiting 586 // on the SR_lock below provides a much more predictable scale up for 587 // the delay. It also provides a simple/direct point to check for any 588 // safepoint requests from the VMThread 589 590 { 591 MutexLocker ml(SR_lock()); 592 // wait with safepoint check (if we're a JavaThread - the WatcherThread 593 // can also call this) and increase delay with each retry 594 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 595 596 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 597 delay, bits); 598 599 // It is possible for the external suspend request to be cancelled 600 // (by a resume) before the actual suspend operation is completed. 601 // Refresh our local copy to see if we still need to wait. 602 pending = is_external_suspend(); 603 } 604 605 if (!pending) { 606 // A cancelled suspend request is the only false return from 607 // is_ext_suspend_completed() that keeps us from staying in the 608 // retry loop. 609 *bits |= 0x00080000; 610 return false; 611 } 612 613 if (is_suspended) { 614 *bits |= 0x00100000; 615 return true; 616 } 617 } // end retry loop 618 619 // thread did not suspend after all our retries 620 *bits |= 0x00200000; 621 return false; 622 } 623 624 #ifndef PRODUCT 625 void JavaThread::record_jump(address target, address instr, const char* file, int line) { 626 627 // This should not need to be atomic as the only way for simultaneous 628 // updates is via interrupts. Even then this should be rare or non-existant 629 // and we don't care that much anyway. 630 631 int index = _jmp_ring_index; 632 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1); 633 _jmp_ring[index]._target = (intptr_t) target; 634 _jmp_ring[index]._instruction = (intptr_t) instr; 635 _jmp_ring[index]._file = file; 636 _jmp_ring[index]._line = line; 637 } 638 #endif /* PRODUCT */ 639 640 // Called by flat profiler 641 // Callers have already called wait_for_ext_suspend_completion 642 // The assertion for that is currently too complex to put here: 643 bool JavaThread::profile_last_Java_frame(frame* _fr) { 644 bool gotframe = false; 645 // self suspension saves needed state. 646 if (has_last_Java_frame() && _anchor.walkable()) { 647 *_fr = pd_last_frame(); 648 gotframe = true; 649 } 650 return gotframe; 651 } 652 653 void Thread::interrupt(Thread* thread) { 654 trace("interrupt", thread); 655 debug_only(check_for_dangling_thread_pointer(thread);) 656 os::interrupt(thread); 657 } 658 659 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 660 trace("is_interrupted", thread); 661 debug_only(check_for_dangling_thread_pointer(thread);) 662 // Note: If clear_interrupted==false, this simply fetches and 663 // returns the value of the field osthread()->interrupted(). 664 return os::is_interrupted(thread, clear_interrupted); 665 } 666 667 668 // GC Support 669 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 670 jint thread_parity = _oops_do_parity; 671 if (thread_parity != strong_roots_parity) { 672 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 673 if (res == thread_parity) return true; 674 else { 675 guarantee(res == strong_roots_parity, "Or else what?"); 676 assert(SharedHeap::heap()->n_par_threads() > 0, 677 "Should only fail when parallel."); 678 return false; 679 } 680 } 681 assert(SharedHeap::heap()->n_par_threads() > 0, 682 "Should only fail when parallel."); 683 return false; 684 } 685 686 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 687 active_handles()->oops_do(f); 688 // Do oop for ThreadShadow 689 f->do_oop((oop*)&_pending_exception); 690 handle_area()->oops_do(f); 691 } 692 693 void Thread::nmethods_do(CodeBlobClosure* cf) { 694 // no nmethods in a generic thread... 695 } 696 697 void Thread::print_on(outputStream* st) const { 698 // get_priority assumes osthread initialized 699 if (osthread() != NULL) { 700 st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this); 701 osthread()->print_on(st); 702 } 703 debug_only(if (WizardMode) print_owned_locks_on(st);) 704 } 705 706 // Thread::print_on_error() is called by fatal error handler. Don't use 707 // any lock or allocate memory. 708 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 709 if (is_VM_thread()) st->print("VMThread"); 710 else if (is_Compiler_thread()) st->print("CompilerThread"); 711 else if (is_Java_thread()) st->print("JavaThread"); 712 else if (is_GC_task_thread()) st->print("GCTaskThread"); 713 else if (is_Watcher_thread()) st->print("WatcherThread"); 714 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 715 else st->print("Thread"); 716 717 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 718 _stack_base - _stack_size, _stack_base); 719 720 if (osthread()) { 721 st->print(" [id=%d]", osthread()->thread_id()); 722 } 723 } 724 725 #ifdef ASSERT 726 void Thread::print_owned_locks_on(outputStream* st) const { 727 Monitor *cur = _owned_locks; 728 if (cur == NULL) { 729 st->print(" (no locks) "); 730 } else { 731 st->print_cr(" Locks owned:"); 732 while(cur) { 733 cur->print_on(st); 734 cur = cur->next(); 735 } 736 } 737 } 738 739 static int ref_use_count = 0; 740 741 bool Thread::owns_locks_but_compiled_lock() const { 742 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 743 if (cur != Compile_lock) return true; 744 } 745 return false; 746 } 747 748 749 #endif 750 751 #ifndef PRODUCT 752 753 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 754 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 755 // no threads which allow_vm_block's are held 756 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 757 // Check if current thread is allowed to block at a safepoint 758 if (!(_allow_safepoint_count == 0)) 759 fatal("Possible safepoint reached by thread that does not allow it"); 760 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 761 fatal("LEAF method calling lock?"); 762 } 763 764 #ifdef ASSERT 765 if (potential_vm_operation && is_Java_thread() 766 && !Universe::is_bootstrapping()) { 767 // Make sure we do not hold any locks that the VM thread also uses. 768 // This could potentially lead to deadlocks 769 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 770 // Threads_lock is special, since the safepoint synchronization will not start before this is 771 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 772 // since it is used to transfer control between JavaThreads and the VMThread 773 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first! 774 if ( (cur->allow_vm_block() && 775 cur != Threads_lock && 776 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation 777 cur != VMOperationRequest_lock && 778 cur != VMOperationQueue_lock) || 779 cur->rank() == Mutex::special) { 780 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 781 } 782 } 783 } 784 785 if (GCALotAtAllSafepoints) { 786 // We could enter a safepoint here and thus have a gc 787 InterfaceSupport::check_gc_alot(); 788 } 789 #endif 790 } 791 #endif 792 793 bool Thread::is_in_stack(address adr) const { 794 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 795 address end = os::current_stack_pointer(); 796 if (stack_base() >= adr && adr >= end) return true; 797 798 return false; 799 } 800 801 802 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 803 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 804 // used for compilation in the future. If that change is made, the need for these methods 805 // should be revisited, and they should be removed if possible. 806 807 bool Thread::is_lock_owned(address adr) const { 808 return (_stack_base >= adr && adr >= (_stack_base - _stack_size)); 809 } 810 811 bool Thread::set_as_starting_thread() { 812 // NOTE: this must be called inside the main thread. 813 return os::create_main_thread((JavaThread*)this); 814 } 815 816 static void initialize_class(symbolHandle class_name, TRAPS) { 817 klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 818 instanceKlass::cast(klass)->initialize(CHECK); 819 } 820 821 822 // Creates the initial ThreadGroup 823 static Handle create_initial_thread_group(TRAPS) { 824 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_ThreadGroup(), true, CHECK_NH); 825 instanceKlassHandle klass (THREAD, k); 826 827 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 828 { 829 JavaValue result(T_VOID); 830 JavaCalls::call_special(&result, 831 system_instance, 832 klass, 833 vmSymbolHandles::object_initializer_name(), 834 vmSymbolHandles::void_method_signature(), 835 CHECK_NH); 836 } 837 Universe::set_system_thread_group(system_instance()); 838 839 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 840 { 841 JavaValue result(T_VOID); 842 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 843 JavaCalls::call_special(&result, 844 main_instance, 845 klass, 846 vmSymbolHandles::object_initializer_name(), 847 vmSymbolHandles::threadgroup_string_void_signature(), 848 system_instance, 849 string, 850 CHECK_NH); 851 } 852 return main_instance; 853 } 854 855 // Creates the initial Thread 856 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 857 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK_NULL); 858 instanceKlassHandle klass (THREAD, k); 859 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 860 861 java_lang_Thread::set_thread(thread_oop(), thread); 862 java_lang_Thread::set_priority(thread_oop(), NormPriority); 863 thread->set_threadObj(thread_oop()); 864 865 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 866 867 JavaValue result(T_VOID); 868 JavaCalls::call_special(&result, thread_oop, 869 klass, 870 vmSymbolHandles::object_initializer_name(), 871 vmSymbolHandles::threadgroup_string_void_signature(), 872 thread_group, 873 string, 874 CHECK_NULL); 875 return thread_oop(); 876 } 877 878 static void call_initializeSystemClass(TRAPS) { 879 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK); 880 instanceKlassHandle klass (THREAD, k); 881 882 JavaValue result(T_VOID); 883 JavaCalls::call_static(&result, klass, vmSymbolHandles::initializeSystemClass_name(), 884 vmSymbolHandles::void_method_signature(), CHECK); 885 } 886 887 static void reset_vm_info_property(TRAPS) { 888 // the vm info string 889 ResourceMark rm(THREAD); 890 const char *vm_info = VM_Version::vm_info_string(); 891 892 // java.lang.System class 893 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK); 894 instanceKlassHandle klass (THREAD, k); 895 896 // setProperty arguments 897 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 898 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 899 900 // return value 901 JavaValue r(T_OBJECT); 902 903 // public static String setProperty(String key, String value); 904 JavaCalls::call_static(&r, 905 klass, 906 vmSymbolHandles::setProperty_name(), 907 vmSymbolHandles::string_string_string_signature(), 908 key_str, 909 value_str, 910 CHECK); 911 } 912 913 914 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 915 assert(thread_group.not_null(), "thread group should be specified"); 916 assert(threadObj() == NULL, "should only create Java thread object once"); 917 918 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK); 919 instanceKlassHandle klass (THREAD, k); 920 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 921 922 java_lang_Thread::set_thread(thread_oop(), this); 923 java_lang_Thread::set_priority(thread_oop(), NormPriority); 924 set_threadObj(thread_oop()); 925 926 JavaValue result(T_VOID); 927 if (thread_name != NULL) { 928 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 929 // Thread gets assigned specified name and null target 930 JavaCalls::call_special(&result, 931 thread_oop, 932 klass, 933 vmSymbolHandles::object_initializer_name(), 934 vmSymbolHandles::threadgroup_string_void_signature(), 935 thread_group, // Argument 1 936 name, // Argument 2 937 THREAD); 938 } else { 939 // Thread gets assigned name "Thread-nnn" and null target 940 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 941 JavaCalls::call_special(&result, 942 thread_oop, 943 klass, 944 vmSymbolHandles::object_initializer_name(), 945 vmSymbolHandles::threadgroup_runnable_void_signature(), 946 thread_group, // Argument 1 947 Handle(), // Argument 2 948 THREAD); 949 } 950 951 952 if (daemon) { 953 java_lang_Thread::set_daemon(thread_oop()); 954 } 955 956 if (HAS_PENDING_EXCEPTION) { 957 return; 958 } 959 960 KlassHandle group(this, SystemDictionary::threadGroup_klass()); 961 Handle threadObj(this, this->threadObj()); 962 963 JavaCalls::call_special(&result, 964 thread_group, 965 group, 966 vmSymbolHandles::add_method_name(), 967 vmSymbolHandles::thread_void_signature(), 968 threadObj, // Arg 1 969 THREAD); 970 971 972 } 973 974 // NamedThread -- non-JavaThread subclasses with multiple 975 // uniquely named instances should derive from this. 976 NamedThread::NamedThread() : Thread() { 977 _name = NULL; 978 } 979 980 NamedThread::~NamedThread() { 981 if (_name != NULL) { 982 FREE_C_HEAP_ARRAY(char, _name); 983 _name = NULL; 984 } 985 } 986 987 void NamedThread::set_name(const char* format, ...) { 988 guarantee(_name == NULL, "Only get to set name once."); 989 _name = NEW_C_HEAP_ARRAY(char, max_name_len); 990 guarantee(_name != NULL, "alloc failure"); 991 va_list ap; 992 va_start(ap, format); 993 jio_vsnprintf(_name, max_name_len, format, ap); 994 va_end(ap); 995 } 996 997 // ======= WatcherThread ======== 998 999 // The watcher thread exists to simulate timer interrupts. It should 1000 // be replaced by an abstraction over whatever native support for 1001 // timer interrupts exists on the platform. 1002 1003 WatcherThread* WatcherThread::_watcher_thread = NULL; 1004 bool WatcherThread::_should_terminate = false; 1005 1006 WatcherThread::WatcherThread() : Thread() { 1007 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1008 if (os::create_thread(this, os::watcher_thread)) { 1009 _watcher_thread = this; 1010 1011 // Set the watcher thread to the highest OS priority which should not be 1012 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1013 // is created. The only normal thread using this priority is the reference 1014 // handler thread, which runs for very short intervals only. 1015 // If the VMThread's priority is not lower than the WatcherThread profiling 1016 // will be inaccurate. 1017 os::set_priority(this, MaxPriority); 1018 if (!DisableStartThread) { 1019 os::start_thread(this); 1020 } 1021 } 1022 } 1023 1024 void WatcherThread::run() { 1025 assert(this == watcher_thread(), "just checking"); 1026 1027 this->record_stack_base_and_size(); 1028 this->initialize_thread_local_storage(); 1029 this->set_active_handles(JNIHandleBlock::allocate_block()); 1030 while(!_should_terminate) { 1031 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1032 assert(watcher_thread() == this, "thread consistency check"); 1033 1034 // Calculate how long it'll be until the next PeriodicTask work 1035 // should be done, and sleep that amount of time. 1036 const size_t time_to_wait = PeriodicTask::time_to_wait(); 1037 os::sleep(this, time_to_wait, false); 1038 1039 if (is_error_reported()) { 1040 // A fatal error has happened, the error handler(VMError::report_and_die) 1041 // should abort JVM after creating an error log file. However in some 1042 // rare cases, the error handler itself might deadlock. Here we try to 1043 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1044 // 1045 // This code is in WatcherThread because WatcherThread wakes up 1046 // periodically so the fatal error handler doesn't need to do anything; 1047 // also because the WatcherThread is less likely to crash than other 1048 // threads. 1049 1050 for (;;) { 1051 if (!ShowMessageBoxOnError 1052 && (OnError == NULL || OnError[0] == '\0') 1053 && Arguments::abort_hook() == NULL) { 1054 os::sleep(this, 2 * 60 * 1000, false); 1055 fdStream err(defaultStream::output_fd()); 1056 err.print_raw_cr("# [ timer expired, abort... ]"); 1057 // skip atexit/vm_exit/vm_abort hooks 1058 os::die(); 1059 } 1060 1061 // Wake up 5 seconds later, the fatal handler may reset OnError or 1062 // ShowMessageBoxOnError when it is ready to abort. 1063 os::sleep(this, 5 * 1000, false); 1064 } 1065 } 1066 1067 PeriodicTask::real_time_tick(time_to_wait); 1068 1069 // If we have no more tasks left due to dynamic disenrollment, 1070 // shut down the thread since we don't currently support dynamic enrollment 1071 if (PeriodicTask::num_tasks() == 0) { 1072 _should_terminate = true; 1073 } 1074 } 1075 1076 // Signal that it is terminated 1077 { 1078 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1079 _watcher_thread = NULL; 1080 Terminator_lock->notify(); 1081 } 1082 1083 // Thread destructor usually does this.. 1084 ThreadLocalStorage::set_thread(NULL); 1085 } 1086 1087 void WatcherThread::start() { 1088 if (watcher_thread() == NULL) { 1089 _should_terminate = false; 1090 // Create the single instance of WatcherThread 1091 new WatcherThread(); 1092 } 1093 } 1094 1095 void WatcherThread::stop() { 1096 // it is ok to take late safepoints here, if needed 1097 MutexLocker mu(Terminator_lock); 1098 _should_terminate = true; 1099 while(watcher_thread() != NULL) { 1100 // This wait should make safepoint checks, wait without a timeout, 1101 // and wait as a suspend-equivalent condition. 1102 // 1103 // Note: If the FlatProfiler is running, then this thread is waiting 1104 // for the WatcherThread to terminate and the WatcherThread, via the 1105 // FlatProfiler task, is waiting for the external suspend request on 1106 // this thread to complete. wait_for_ext_suspend_completion() will 1107 // eventually timeout, but that takes time. Making this wait a 1108 // suspend-equivalent condition solves that timeout problem. 1109 // 1110 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1111 Mutex::_as_suspend_equivalent_flag); 1112 } 1113 } 1114 1115 void WatcherThread::print_on(outputStream* st) const { 1116 st->print("\"%s\" ", name()); 1117 Thread::print_on(st); 1118 st->cr(); 1119 } 1120 1121 // ======= JavaThread ======== 1122 1123 // A JavaThread is a normal Java thread 1124 1125 void JavaThread::initialize() { 1126 // Initialize fields 1127 1128 // Set the claimed par_id to -1 (ie not claiming any par_ids) 1129 set_claimed_par_id(-1); 1130 1131 set_saved_exception_pc(NULL); 1132 set_threadObj(NULL); 1133 _anchor.clear(); 1134 set_entry_point(NULL); 1135 set_jni_functions(jni_functions()); 1136 set_callee_target(NULL); 1137 set_vm_result(NULL); 1138 set_vm_result_2(NULL); 1139 set_vframe_array_head(NULL); 1140 set_vframe_array_last(NULL); 1141 set_deferred_locals(NULL); 1142 set_deopt_mark(NULL); 1143 clear_must_deopt_id(); 1144 set_monitor_chunks(NULL); 1145 set_next(NULL); 1146 set_thread_state(_thread_new); 1147 _terminated = _not_terminated; 1148 _privileged_stack_top = NULL; 1149 _array_for_gc = NULL; 1150 _suspend_equivalent = false; 1151 _in_deopt_handler = 0; 1152 _doing_unsafe_access = false; 1153 _stack_guard_state = stack_guard_unused; 1154 _exception_oop = NULL; 1155 _exception_pc = 0; 1156 _exception_handler_pc = 0; 1157 _exception_stack_size = 0; 1158 _jvmti_thread_state= NULL; 1159 _jvmti_get_loaded_classes_closure = NULL; 1160 _interp_only_mode = 0; 1161 _special_runtime_exit_condition = _no_async_condition; 1162 _pending_async_exception = NULL; 1163 _is_compiling = false; 1164 _thread_stat = NULL; 1165 _thread_stat = new ThreadStatistics(); 1166 _blocked_on_compilation = false; 1167 _jni_active_critical = 0; 1168 _do_not_unlock_if_synchronized = false; 1169 _cached_monitor_info = NULL; 1170 _parker = Parker::Allocate(this) ; 1171 1172 #ifndef PRODUCT 1173 _jmp_ring_index = 0; 1174 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) { 1175 record_jump(NULL, NULL, NULL, 0); 1176 } 1177 #endif /* PRODUCT */ 1178 1179 set_thread_profiler(NULL); 1180 if (FlatProfiler::is_active()) { 1181 // This is where we would decide to either give each thread it's own profiler 1182 // or use one global one from FlatProfiler, 1183 // or up to some count of the number of profiled threads, etc. 1184 ThreadProfiler* pp = new ThreadProfiler(); 1185 pp->engage(); 1186 set_thread_profiler(pp); 1187 } 1188 1189 // Setup safepoint state info for this thread 1190 ThreadSafepointState::create(this); 1191 1192 debug_only(_java_call_counter = 0); 1193 1194 // JVMTI PopFrame support 1195 _popframe_condition = popframe_inactive; 1196 _popframe_preserved_args = NULL; 1197 _popframe_preserved_args_size = 0; 1198 1199 pd_initialize(); 1200 } 1201 1202 #ifndef SERIALGC 1203 SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1204 DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1205 #endif // !SERIALGC 1206 1207 JavaThread::JavaThread(bool is_attaching) : 1208 Thread() 1209 #ifndef SERIALGC 1210 , _satb_mark_queue(&_satb_mark_queue_set), 1211 _dirty_card_queue(&_dirty_card_queue_set) 1212 #endif // !SERIALGC 1213 { 1214 initialize(); 1215 _is_attaching = is_attaching; 1216 assert(_deferred_card_mark.is_empty(), "Default MemRegion ctor"); 1217 } 1218 1219 bool JavaThread::reguard_stack(address cur_sp) { 1220 if (_stack_guard_state != stack_guard_yellow_disabled) { 1221 return true; // Stack already guarded or guard pages not needed. 1222 } 1223 1224 if (register_stack_overflow()) { 1225 // For those architectures which have separate register and 1226 // memory stacks, we must check the register stack to see if 1227 // it has overflowed. 1228 return false; 1229 } 1230 1231 // Java code never executes within the yellow zone: the latter is only 1232 // there to provoke an exception during stack banging. If java code 1233 // is executing there, either StackShadowPages should be larger, or 1234 // some exception code in c1, c2 or the interpreter isn't unwinding 1235 // when it should. 1236 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1237 1238 enable_stack_yellow_zone(); 1239 return true; 1240 } 1241 1242 bool JavaThread::reguard_stack(void) { 1243 return reguard_stack(os::current_stack_pointer()); 1244 } 1245 1246 1247 void JavaThread::block_if_vm_exited() { 1248 if (_terminated == _vm_exited) { 1249 // _vm_exited is set at safepoint, and Threads_lock is never released 1250 // we will block here forever 1251 Threads_lock->lock_without_safepoint_check(); 1252 ShouldNotReachHere(); 1253 } 1254 } 1255 1256 1257 // Remove this ifdef when C1 is ported to the compiler interface. 1258 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1259 1260 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1261 Thread() 1262 #ifndef SERIALGC 1263 , _satb_mark_queue(&_satb_mark_queue_set), 1264 _dirty_card_queue(&_dirty_card_queue_set) 1265 #endif // !SERIALGC 1266 { 1267 if (TraceThreadEvents) { 1268 tty->print_cr("creating thread %p", this); 1269 } 1270 initialize(); 1271 _is_attaching = false; 1272 set_entry_point(entry_point); 1273 // Create the native thread itself. 1274 // %note runtime_23 1275 os::ThreadType thr_type = os::java_thread; 1276 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1277 os::java_thread; 1278 os::create_thread(this, thr_type, stack_sz); 1279 1280 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1281 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1282 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1283 // the exception consists of creating the exception object & initializing it, initialization 1284 // will leave the VM via a JavaCall and then all locks must be unlocked). 1285 // 1286 // The thread is still suspended when we reach here. Thread must be explicit started 1287 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1288 // by calling Threads:add. The reason why this is not done here, is because the thread 1289 // object must be fully initialized (take a look at JVM_Start) 1290 } 1291 1292 JavaThread::~JavaThread() { 1293 if (TraceThreadEvents) { 1294 tty->print_cr("terminate thread %p", this); 1295 } 1296 1297 // JSR166 -- return the parker to the free list 1298 Parker::Release(_parker); 1299 _parker = NULL ; 1300 1301 // Free any remaining previous UnrollBlock 1302 vframeArray* old_array = vframe_array_last(); 1303 1304 if (old_array != NULL) { 1305 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1306 old_array->set_unroll_block(NULL); 1307 delete old_info; 1308 delete old_array; 1309 } 1310 1311 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1312 if (deferred != NULL) { 1313 // This can only happen if thread is destroyed before deoptimization occurs. 1314 assert(deferred->length() != 0, "empty array!"); 1315 do { 1316 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1317 deferred->remove_at(0); 1318 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1319 delete dlv; 1320 } while (deferred->length() != 0); 1321 delete deferred; 1322 } 1323 1324 // All Java related clean up happens in exit 1325 ThreadSafepointState::destroy(this); 1326 if (_thread_profiler != NULL) delete _thread_profiler; 1327 if (_thread_stat != NULL) delete _thread_stat; 1328 } 1329 1330 1331 // The first routine called by a new Java thread 1332 void JavaThread::run() { 1333 // initialize thread-local alloc buffer related fields 1334 this->initialize_tlab(); 1335 1336 // used to test validitity of stack trace backs 1337 this->record_base_of_stack_pointer(); 1338 1339 // Record real stack base and size. 1340 this->record_stack_base_and_size(); 1341 1342 // Initialize thread local storage; set before calling MutexLocker 1343 this->initialize_thread_local_storage(); 1344 1345 this->create_stack_guard_pages(); 1346 1347 // Thread is now sufficient initialized to be handled by the safepoint code as being 1348 // in the VM. Change thread state from _thread_new to _thread_in_vm 1349 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1350 1351 assert(JavaThread::current() == this, "sanity check"); 1352 assert(!Thread::current()->owns_locks(), "sanity check"); 1353 1354 DTRACE_THREAD_PROBE(start, this); 1355 1356 // This operation might block. We call that after all safepoint checks for a new thread has 1357 // been completed. 1358 this->set_active_handles(JNIHandleBlock::allocate_block()); 1359 1360 if (JvmtiExport::should_post_thread_life()) { 1361 JvmtiExport::post_thread_start(this); 1362 } 1363 1364 // We call another function to do the rest so we are sure that the stack addresses used 1365 // from there will be lower than the stack base just computed 1366 thread_main_inner(); 1367 1368 // Note, thread is no longer valid at this point! 1369 } 1370 1371 1372 void JavaThread::thread_main_inner() { 1373 assert(JavaThread::current() == this, "sanity check"); 1374 assert(this->threadObj() != NULL, "just checking"); 1375 1376 // Execute thread entry point. If this thread is being asked to restart, 1377 // or has been stopped before starting, do not reexecute entry point. 1378 // Note: Due to JVM_StopThread we can have pending exceptions already! 1379 if (!this->has_pending_exception() && !java_lang_Thread::is_stillborn(this->threadObj())) { 1380 // enter the thread's entry point only if we have no pending exceptions 1381 HandleMark hm(this); 1382 this->entry_point()(this, this); 1383 } 1384 1385 DTRACE_THREAD_PROBE(stop, this); 1386 1387 this->exit(false); 1388 delete this; 1389 } 1390 1391 1392 static void ensure_join(JavaThread* thread) { 1393 // We do not need to grap the Threads_lock, since we are operating on ourself. 1394 Handle threadObj(thread, thread->threadObj()); 1395 assert(threadObj.not_null(), "java thread object must exist"); 1396 ObjectLocker lock(threadObj, thread); 1397 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1398 thread->clear_pending_exception(); 1399 // It is of profound importance that we set the stillborn bit and reset the thread object, 1400 // before we do the notify. Since, changing these two variable will make JVM_IsAlive return 1401 // false. So in case another thread is doing a join on this thread , it will detect that the thread 1402 // is dead when it gets notified. 1403 java_lang_Thread::set_stillborn(threadObj()); 1404 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1405 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1406 java_lang_Thread::set_thread(threadObj(), NULL); 1407 lock.notify_all(thread); 1408 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1409 thread->clear_pending_exception(); 1410 } 1411 1412 1413 // For any new cleanup additions, please check to see if they need to be applied to 1414 // cleanup_failed_attach_current_thread as well. 1415 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1416 assert(this == JavaThread::current(), "thread consistency check"); 1417 if (!InitializeJavaLangSystem) return; 1418 1419 HandleMark hm(this); 1420 Handle uncaught_exception(this, this->pending_exception()); 1421 this->clear_pending_exception(); 1422 Handle threadObj(this, this->threadObj()); 1423 assert(threadObj.not_null(), "Java thread object should be created"); 1424 1425 if (get_thread_profiler() != NULL) { 1426 get_thread_profiler()->disengage(); 1427 ResourceMark rm; 1428 get_thread_profiler()->print(get_thread_name()); 1429 } 1430 1431 1432 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1433 { 1434 EXCEPTION_MARK; 1435 1436 CLEAR_PENDING_EXCEPTION; 1437 } 1438 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1439 // has to be fixed by a runtime query method 1440 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1441 // JSR-166: change call from from ThreadGroup.uncaughtException to 1442 // java.lang.Thread.dispatchUncaughtException 1443 if (uncaught_exception.not_null()) { 1444 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1445 Events::log("uncaught exception INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT", 1446 (address)uncaught_exception(), (address)threadObj(), (address)group()); 1447 { 1448 EXCEPTION_MARK; 1449 // Check if the method Thread.dispatchUncaughtException() exists. If so 1450 // call it. Otherwise we have an older library without the JSR-166 changes, 1451 // so call ThreadGroup.uncaughtException() 1452 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1453 CallInfo callinfo; 1454 KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass()); 1455 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1456 vmSymbolHandles::dispatchUncaughtException_name(), 1457 vmSymbolHandles::throwable_void_signature(), 1458 KlassHandle(), false, false, THREAD); 1459 CLEAR_PENDING_EXCEPTION; 1460 methodHandle method = callinfo.selected_method(); 1461 if (method.not_null()) { 1462 JavaValue result(T_VOID); 1463 JavaCalls::call_virtual(&result, 1464 threadObj, thread_klass, 1465 vmSymbolHandles::dispatchUncaughtException_name(), 1466 vmSymbolHandles::throwable_void_signature(), 1467 uncaught_exception, 1468 THREAD); 1469 } else { 1470 KlassHandle thread_group(THREAD, SystemDictionary::threadGroup_klass()); 1471 JavaValue result(T_VOID); 1472 JavaCalls::call_virtual(&result, 1473 group, thread_group, 1474 vmSymbolHandles::uncaughtException_name(), 1475 vmSymbolHandles::thread_throwable_void_signature(), 1476 threadObj, // Arg 1 1477 uncaught_exception, // Arg 2 1478 THREAD); 1479 } 1480 CLEAR_PENDING_EXCEPTION; 1481 } 1482 } 1483 1484 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1485 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1486 // is deprecated anyhow. 1487 { int count = 3; 1488 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1489 EXCEPTION_MARK; 1490 JavaValue result(T_VOID); 1491 KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass()); 1492 JavaCalls::call_virtual(&result, 1493 threadObj, thread_klass, 1494 vmSymbolHandles::exit_method_name(), 1495 vmSymbolHandles::void_method_signature(), 1496 THREAD); 1497 CLEAR_PENDING_EXCEPTION; 1498 } 1499 } 1500 1501 // notify JVMTI 1502 if (JvmtiExport::should_post_thread_life()) { 1503 JvmtiExport::post_thread_end(this); 1504 } 1505 1506 // We have notified the agents that we are exiting, before we go on, 1507 // we must check for a pending external suspend request and honor it 1508 // in order to not surprise the thread that made the suspend request. 1509 while (true) { 1510 { 1511 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1512 if (!is_external_suspend()) { 1513 set_terminated(_thread_exiting); 1514 ThreadService::current_thread_exiting(this); 1515 break; 1516 } 1517 // Implied else: 1518 // Things get a little tricky here. We have a pending external 1519 // suspend request, but we are holding the SR_lock so we 1520 // can't just self-suspend. So we temporarily drop the lock 1521 // and then self-suspend. 1522 } 1523 1524 ThreadBlockInVM tbivm(this); 1525 java_suspend_self(); 1526 1527 // We're done with this suspend request, but we have to loop around 1528 // and check again. Eventually we will get SR_lock without a pending 1529 // external suspend request and will be able to mark ourselves as 1530 // exiting. 1531 } 1532 // no more external suspends are allowed at this point 1533 } else { 1534 // before_exit() has already posted JVMTI THREAD_END events 1535 } 1536 1537 // Notify waiters on thread object. This has to be done after exit() is called 1538 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1539 // group should have the destroyed bit set before waiters are notified). 1540 ensure_join(this); 1541 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1542 1543 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1544 // held by this thread must be released. A detach operation must only 1545 // get here if there are no Java frames on the stack. Therefore, any 1546 // owned monitors at this point MUST be JNI-acquired monitors which are 1547 // pre-inflated and in the monitor cache. 1548 // 1549 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1550 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1551 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1552 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1553 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1554 } 1555 1556 // These things needs to be done while we are still a Java Thread. Make sure that thread 1557 // is in a consistent state, in case GC happens 1558 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1559 1560 if (active_handles() != NULL) { 1561 JNIHandleBlock* block = active_handles(); 1562 set_active_handles(NULL); 1563 JNIHandleBlock::release_block(block); 1564 } 1565 1566 if (free_handle_block() != NULL) { 1567 JNIHandleBlock* block = free_handle_block(); 1568 set_free_handle_block(NULL); 1569 JNIHandleBlock::release_block(block); 1570 } 1571 1572 // These have to be removed while this is still a valid thread. 1573 remove_stack_guard_pages(); 1574 1575 if (UseTLAB) { 1576 tlab().make_parsable(true); // retire TLAB 1577 } 1578 1579 if (jvmti_thread_state() != NULL) { 1580 JvmtiExport::cleanup_thread(this); 1581 } 1582 1583 #ifndef SERIALGC 1584 // We must flush G1-related buffers before removing a thread from 1585 // the list of active threads. 1586 if (UseG1GC) { 1587 flush_barrier_queues(); 1588 } 1589 #endif 1590 1591 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1592 Threads::remove(this); 1593 } 1594 1595 #ifndef SERIALGC 1596 // Flush G1-related queues. 1597 void JavaThread::flush_barrier_queues() { 1598 satb_mark_queue().flush(); 1599 dirty_card_queue().flush(); 1600 } 1601 #endif 1602 1603 void JavaThread::cleanup_failed_attach_current_thread() { 1604 if (get_thread_profiler() != NULL) { 1605 get_thread_profiler()->disengage(); 1606 ResourceMark rm; 1607 get_thread_profiler()->print(get_thread_name()); 1608 } 1609 1610 if (active_handles() != NULL) { 1611 JNIHandleBlock* block = active_handles(); 1612 set_active_handles(NULL); 1613 JNIHandleBlock::release_block(block); 1614 } 1615 1616 if (free_handle_block() != NULL) { 1617 JNIHandleBlock* block = free_handle_block(); 1618 set_free_handle_block(NULL); 1619 JNIHandleBlock::release_block(block); 1620 } 1621 1622 if (UseTLAB) { 1623 tlab().make_parsable(true); // retire TLAB, if any 1624 } 1625 1626 #ifndef SERIALGC 1627 if (UseG1GC) { 1628 flush_barrier_queues(); 1629 } 1630 #endif 1631 1632 Threads::remove(this); 1633 delete this; 1634 } 1635 1636 1637 1638 1639 JavaThread* JavaThread::active() { 1640 Thread* thread = ThreadLocalStorage::thread(); 1641 assert(thread != NULL, "just checking"); 1642 if (thread->is_Java_thread()) { 1643 return (JavaThread*) thread; 1644 } else { 1645 assert(thread->is_VM_thread(), "this must be a vm thread"); 1646 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1647 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1648 assert(ret->is_Java_thread(), "must be a Java thread"); 1649 return ret; 1650 } 1651 } 1652 1653 bool JavaThread::is_lock_owned(address adr) const { 1654 if (Thread::is_lock_owned(adr)) return true; 1655 1656 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 1657 if (chunk->contains(adr)) return true; 1658 } 1659 1660 return false; 1661 } 1662 1663 1664 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 1665 chunk->set_next(monitor_chunks()); 1666 set_monitor_chunks(chunk); 1667 } 1668 1669 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 1670 guarantee(monitor_chunks() != NULL, "must be non empty"); 1671 if (monitor_chunks() == chunk) { 1672 set_monitor_chunks(chunk->next()); 1673 } else { 1674 MonitorChunk* prev = monitor_chunks(); 1675 while (prev->next() != chunk) prev = prev->next(); 1676 prev->set_next(chunk->next()); 1677 } 1678 } 1679 1680 // JVM support. 1681 1682 // Note: this function shouldn't block if it's called in 1683 // _thread_in_native_trans state (such as from 1684 // check_special_condition_for_native_trans()). 1685 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 1686 1687 if (has_last_Java_frame() && has_async_condition()) { 1688 // If we are at a polling page safepoint (not a poll return) 1689 // then we must defer async exception because live registers 1690 // will be clobbered by the exception path. Poll return is 1691 // ok because the call we a returning from already collides 1692 // with exception handling registers and so there is no issue. 1693 // (The exception handling path kills call result registers but 1694 // this is ok since the exception kills the result anyway). 1695 1696 if (is_at_poll_safepoint()) { 1697 // if the code we are returning to has deoptimized we must defer 1698 // the exception otherwise live registers get clobbered on the 1699 // exception path before deoptimization is able to retrieve them. 1700 // 1701 RegisterMap map(this, false); 1702 frame caller_fr = last_frame().sender(&map); 1703 assert(caller_fr.is_compiled_frame(), "what?"); 1704 if (caller_fr.is_deoptimized_frame()) { 1705 if (TraceExceptions) { 1706 ResourceMark rm; 1707 tty->print_cr("deferred async exception at compiled safepoint"); 1708 } 1709 return; 1710 } 1711 } 1712 } 1713 1714 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 1715 if (condition == _no_async_condition) { 1716 // Conditions have changed since has_special_runtime_exit_condition() 1717 // was called: 1718 // - if we were here only because of an external suspend request, 1719 // then that was taken care of above (or cancelled) so we are done 1720 // - if we were here because of another async request, then it has 1721 // been cleared between the has_special_runtime_exit_condition() 1722 // and now so again we are done 1723 return; 1724 } 1725 1726 // Check for pending async. exception 1727 if (_pending_async_exception != NULL) { 1728 // Only overwrite an already pending exception, if it is not a threadDeath. 1729 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::threaddeath_klass())) { 1730 1731 // We cannot call Exceptions::_throw(...) here because we cannot block 1732 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 1733 1734 if (TraceExceptions) { 1735 ResourceMark rm; 1736 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 1737 if (has_last_Java_frame() ) { 1738 frame f = last_frame(); 1739 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 1740 } 1741 tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name()); 1742 } 1743 _pending_async_exception = NULL; 1744 clear_has_async_exception(); 1745 } 1746 } 1747 1748 if (check_unsafe_error && 1749 condition == _async_unsafe_access_error && !has_pending_exception()) { 1750 condition = _no_async_condition; // done 1751 switch (thread_state()) { 1752 case _thread_in_vm: 1753 { 1754 JavaThread* THREAD = this; 1755 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 1756 } 1757 case _thread_in_native: 1758 { 1759 ThreadInVMfromNative tiv(this); 1760 JavaThread* THREAD = this; 1761 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 1762 } 1763 case _thread_in_Java: 1764 { 1765 ThreadInVMfromJava tiv(this); 1766 JavaThread* THREAD = this; 1767 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 1768 } 1769 default: 1770 ShouldNotReachHere(); 1771 } 1772 } 1773 1774 assert(condition == _no_async_condition || has_pending_exception() || 1775 (!check_unsafe_error && condition == _async_unsafe_access_error), 1776 "must have handled the async condition, if no exception"); 1777 } 1778 1779 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 1780 // 1781 // Check for pending external suspend. Internal suspend requests do 1782 // not use handle_special_runtime_exit_condition(). 1783 // If JNIEnv proxies are allowed, don't self-suspend if the target 1784 // thread is not the current thread. In older versions of jdbx, jdbx 1785 // threads could call into the VM with another thread's JNIEnv so we 1786 // can be here operating on behalf of a suspended thread (4432884). 1787 bool do_self_suspend = is_external_suspend_with_lock(); 1788 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 1789 // 1790 // Because thread is external suspended the safepoint code will count 1791 // thread as at a safepoint. This can be odd because we can be here 1792 // as _thread_in_Java which would normally transition to _thread_blocked 1793 // at a safepoint. We would like to mark the thread as _thread_blocked 1794 // before calling java_suspend_self like all other callers of it but 1795 // we must then observe proper safepoint protocol. (We can't leave 1796 // _thread_blocked with a safepoint in progress). However we can be 1797 // here as _thread_in_native_trans so we can't use a normal transition 1798 // constructor/destructor pair because they assert on that type of 1799 // transition. We could do something like: 1800 // 1801 // JavaThreadState state = thread_state(); 1802 // set_thread_state(_thread_in_vm); 1803 // { 1804 // ThreadBlockInVM tbivm(this); 1805 // java_suspend_self() 1806 // } 1807 // set_thread_state(_thread_in_vm_trans); 1808 // if (safepoint) block; 1809 // set_thread_state(state); 1810 // 1811 // but that is pretty messy. Instead we just go with the way the 1812 // code has worked before and note that this is the only path to 1813 // java_suspend_self that doesn't put the thread in _thread_blocked 1814 // mode. 1815 1816 frame_anchor()->make_walkable(this); 1817 java_suspend_self(); 1818 1819 // We might be here for reasons in addition to the self-suspend request 1820 // so check for other async requests. 1821 } 1822 1823 if (check_asyncs) { 1824 check_and_handle_async_exceptions(); 1825 } 1826 } 1827 1828 void JavaThread::send_thread_stop(oop java_throwable) { 1829 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 1830 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 1831 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 1832 1833 // Do not throw asynchronous exceptions against the compiler thread 1834 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 1835 if (is_Compiler_thread()) return; 1836 1837 // This is a change from JDK 1.1, but JDK 1.2 will also do it: 1838 if (java_throwable->is_a(SystemDictionary::threaddeath_klass())) { 1839 java_lang_Thread::set_stillborn(threadObj()); 1840 } 1841 1842 { 1843 // Actually throw the Throwable against the target Thread - however 1844 // only if there is no thread death exception installed already. 1845 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::threaddeath_klass())) { 1846 // If the topmost frame is a runtime stub, then we are calling into 1847 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 1848 // must deoptimize the caller before continuing, as the compiled exception handler table 1849 // may not be valid 1850 if (has_last_Java_frame()) { 1851 frame f = last_frame(); 1852 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 1853 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 1854 RegisterMap reg_map(this, UseBiasedLocking); 1855 frame compiled_frame = f.sender(®_map); 1856 if (compiled_frame.can_be_deoptimized()) { 1857 Deoptimization::deoptimize(this, compiled_frame, ®_map); 1858 } 1859 } 1860 } 1861 1862 // Set async. pending exception in thread. 1863 set_pending_async_exception(java_throwable); 1864 1865 if (TraceExceptions) { 1866 ResourceMark rm; 1867 tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name()); 1868 } 1869 // for AbortVMOnException flag 1870 NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name())); 1871 } 1872 } 1873 1874 1875 // Interrupt thread so it will wake up from a potential wait() 1876 Thread::interrupt(this); 1877 } 1878 1879 // External suspension mechanism. 1880 // 1881 // Tell the VM to suspend a thread when ever it knows that it does not hold on 1882 // to any VM_locks and it is at a transition 1883 // Self-suspension will happen on the transition out of the vm. 1884 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 1885 // 1886 // Guarantees on return: 1887 // + Target thread will not execute any new bytecode (that's why we need to 1888 // force a safepoint) 1889 // + Target thread will not enter any new monitors 1890 // 1891 void JavaThread::java_suspend() { 1892 { MutexLocker mu(Threads_lock); 1893 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 1894 return; 1895 } 1896 } 1897 1898 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1899 if (!is_external_suspend()) { 1900 // a racing resume has cancelled us; bail out now 1901 return; 1902 } 1903 1904 // suspend is done 1905 uint32_t debug_bits = 0; 1906 // Warning: is_ext_suspend_completed() may temporarily drop the 1907 // SR_lock to allow the thread to reach a stable thread state if 1908 // it is currently in a transient thread state. 1909 if (is_ext_suspend_completed(false /* !called_by_wait */, 1910 SuspendRetryDelay, &debug_bits) ) { 1911 return; 1912 } 1913 } 1914 1915 VM_ForceSafepoint vm_suspend; 1916 VMThread::execute(&vm_suspend); 1917 } 1918 1919 // Part II of external suspension. 1920 // A JavaThread self suspends when it detects a pending external suspend 1921 // request. This is usually on transitions. It is also done in places 1922 // where continuing to the next transition would surprise the caller, 1923 // e.g., monitor entry. 1924 // 1925 // Returns the number of times that the thread self-suspended. 1926 // 1927 // Note: DO NOT call java_suspend_self() when you just want to block current 1928 // thread. java_suspend_self() is the second stage of cooperative 1929 // suspension for external suspend requests and should only be used 1930 // to complete an external suspend request. 1931 // 1932 int JavaThread::java_suspend_self() { 1933 int ret = 0; 1934 1935 // we are in the process of exiting so don't suspend 1936 if (is_exiting()) { 1937 clear_external_suspend(); 1938 return ret; 1939 } 1940 1941 assert(_anchor.walkable() || 1942 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 1943 "must have walkable stack"); 1944 1945 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1946 1947 assert(!this->is_ext_suspended(), 1948 "a thread trying to self-suspend should not already be suspended"); 1949 1950 if (this->is_suspend_equivalent()) { 1951 // If we are self-suspending as a result of the lifting of a 1952 // suspend equivalent condition, then the suspend_equivalent 1953 // flag is not cleared until we set the ext_suspended flag so 1954 // that wait_for_ext_suspend_completion() returns consistent 1955 // results. 1956 this->clear_suspend_equivalent(); 1957 } 1958 1959 // A racing resume may have cancelled us before we grabbed SR_lock 1960 // above. Or another external suspend request could be waiting for us 1961 // by the time we return from SR_lock()->wait(). The thread 1962 // that requested the suspension may already be trying to walk our 1963 // stack and if we return now, we can change the stack out from under 1964 // it. This would be a "bad thing (TM)" and cause the stack walker 1965 // to crash. We stay self-suspended until there are no more pending 1966 // external suspend requests. 1967 while (is_external_suspend()) { 1968 ret++; 1969 this->set_ext_suspended(); 1970 1971 // _ext_suspended flag is cleared by java_resume() 1972 while (is_ext_suspended()) { 1973 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 1974 } 1975 } 1976 1977 return ret; 1978 } 1979 1980 #ifdef ASSERT 1981 // verify the JavaThread has not yet been published in the Threads::list, and 1982 // hence doesn't need protection from concurrent access at this stage 1983 void JavaThread::verify_not_published() { 1984 if (!Threads_lock->owned_by_self()) { 1985 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 1986 assert( !Threads::includes(this), 1987 "java thread shouldn't have been published yet!"); 1988 } 1989 else { 1990 assert( !Threads::includes(this), 1991 "java thread shouldn't have been published yet!"); 1992 } 1993 } 1994 #endif 1995 1996 // Slow path when the native==>VM/Java barriers detect a safepoint is in 1997 // progress or when _suspend_flags is non-zero. 1998 // Current thread needs to self-suspend if there is a suspend request and/or 1999 // block if a safepoint is in progress. 2000 // Async exception ISN'T checked. 2001 // Note only the ThreadInVMfromNative transition can call this function 2002 // directly and when thread state is _thread_in_native_trans 2003 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2004 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2005 2006 JavaThread *curJT = JavaThread::current(); 2007 bool do_self_suspend = thread->is_external_suspend(); 2008 2009 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2010 2011 // If JNIEnv proxies are allowed, don't self-suspend if the target 2012 // thread is not the current thread. In older versions of jdbx, jdbx 2013 // threads could call into the VM with another thread's JNIEnv so we 2014 // can be here operating on behalf of a suspended thread (4432884). 2015 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2016 JavaThreadState state = thread->thread_state(); 2017 2018 // We mark this thread_blocked state as a suspend-equivalent so 2019 // that a caller to is_ext_suspend_completed() won't be confused. 2020 // The suspend-equivalent state is cleared by java_suspend_self(). 2021 thread->set_suspend_equivalent(); 2022 2023 // If the safepoint code sees the _thread_in_native_trans state, it will 2024 // wait until the thread changes to other thread state. There is no 2025 // guarantee on how soon we can obtain the SR_lock and complete the 2026 // self-suspend request. It would be a bad idea to let safepoint wait for 2027 // too long. Temporarily change the state to _thread_blocked to 2028 // let the VM thread know that this thread is ready for GC. The problem 2029 // of changing thread state is that safepoint could happen just after 2030 // java_suspend_self() returns after being resumed, and VM thread will 2031 // see the _thread_blocked state. We must check for safepoint 2032 // after restoring the state and make sure we won't leave while a safepoint 2033 // is in progress. 2034 thread->set_thread_state(_thread_blocked); 2035 thread->java_suspend_self(); 2036 thread->set_thread_state(state); 2037 // Make sure new state is seen by VM thread 2038 if (os::is_MP()) { 2039 if (UseMembar) { 2040 // Force a fence between the write above and read below 2041 OrderAccess::fence(); 2042 } else { 2043 // Must use this rather than serialization page in particular on Windows 2044 InterfaceSupport::serialize_memory(thread); 2045 } 2046 } 2047 } 2048 2049 if (SafepointSynchronize::do_call_back()) { 2050 // If we are safepointing, then block the caller which may not be 2051 // the same as the target thread (see above). 2052 SafepointSynchronize::block(curJT); 2053 } 2054 2055 if (thread->is_deopt_suspend()) { 2056 thread->clear_deopt_suspend(); 2057 RegisterMap map(thread, false); 2058 frame f = thread->last_frame(); 2059 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2060 f = f.sender(&map); 2061 } 2062 if (f.id() == thread->must_deopt_id()) { 2063 thread->clear_must_deopt_id(); 2064 // Since we know we're safe to deopt the current state is a safe state 2065 f.deoptimize(thread, true); 2066 } else { 2067 fatal("missed deoptimization!"); 2068 } 2069 } 2070 } 2071 2072 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2073 // progress or when _suspend_flags is non-zero. 2074 // Current thread needs to self-suspend if there is a suspend request and/or 2075 // block if a safepoint is in progress. 2076 // Also check for pending async exception (not including unsafe access error). 2077 // Note only the native==>VM/Java barriers can call this function and when 2078 // thread state is _thread_in_native_trans. 2079 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2080 check_safepoint_and_suspend_for_native_trans(thread); 2081 2082 if (thread->has_async_exception()) { 2083 // We are in _thread_in_native_trans state, don't handle unsafe 2084 // access error since that may block. 2085 thread->check_and_handle_async_exceptions(false); 2086 } 2087 } 2088 2089 // We need to guarantee the Threads_lock here, since resumes are not 2090 // allowed during safepoint synchronization 2091 // Can only resume from an external suspension 2092 void JavaThread::java_resume() { 2093 assert_locked_or_safepoint(Threads_lock); 2094 2095 // Sanity check: thread is gone, has started exiting or the thread 2096 // was not externally suspended. 2097 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2098 return; 2099 } 2100 2101 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2102 2103 clear_external_suspend(); 2104 2105 if (is_ext_suspended()) { 2106 clear_ext_suspended(); 2107 SR_lock()->notify_all(); 2108 } 2109 } 2110 2111 void JavaThread::create_stack_guard_pages() { 2112 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2113 address low_addr = stack_base() - stack_size(); 2114 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2115 2116 int allocate = os::allocate_stack_guard_pages(); 2117 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2118 2119 if (allocate && !os::commit_memory((char *) low_addr, len)) { 2120 warning("Attempt to allocate stack guard pages failed."); 2121 return; 2122 } 2123 2124 if (os::guard_memory((char *) low_addr, len)) { 2125 _stack_guard_state = stack_guard_enabled; 2126 } else { 2127 warning("Attempt to protect stack guard pages failed."); 2128 if (os::uncommit_memory((char *) low_addr, len)) { 2129 warning("Attempt to deallocate stack guard pages failed."); 2130 } 2131 } 2132 } 2133 2134 void JavaThread::remove_stack_guard_pages() { 2135 if (_stack_guard_state == stack_guard_unused) return; 2136 address low_addr = stack_base() - stack_size(); 2137 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2138 2139 if (os::allocate_stack_guard_pages()) { 2140 if (os::uncommit_memory((char *) low_addr, len)) { 2141 _stack_guard_state = stack_guard_unused; 2142 } else { 2143 warning("Attempt to deallocate stack guard pages failed."); 2144 } 2145 } else { 2146 if (_stack_guard_state == stack_guard_unused) return; 2147 if (os::unguard_memory((char *) low_addr, len)) { 2148 _stack_guard_state = stack_guard_unused; 2149 } else { 2150 warning("Attempt to unprotect stack guard pages failed."); 2151 } 2152 } 2153 } 2154 2155 void JavaThread::enable_stack_yellow_zone() { 2156 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2157 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2158 2159 // The base notation is from the stacks point of view, growing downward. 2160 // We need to adjust it to work correctly with guard_memory() 2161 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2162 2163 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2164 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2165 2166 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2167 _stack_guard_state = stack_guard_enabled; 2168 } else { 2169 warning("Attempt to guard stack yellow zone failed."); 2170 } 2171 enable_register_stack_guard(); 2172 } 2173 2174 void JavaThread::disable_stack_yellow_zone() { 2175 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2176 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2177 2178 // Simply return if called for a thread that does not use guard pages. 2179 if (_stack_guard_state == stack_guard_unused) return; 2180 2181 // The base notation is from the stacks point of view, growing downward. 2182 // We need to adjust it to work correctly with guard_memory() 2183 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2184 2185 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2186 _stack_guard_state = stack_guard_yellow_disabled; 2187 } else { 2188 warning("Attempt to unguard stack yellow zone failed."); 2189 } 2190 disable_register_stack_guard(); 2191 } 2192 2193 void JavaThread::enable_stack_red_zone() { 2194 // The base notation is from the stacks point of view, growing downward. 2195 // We need to adjust it to work correctly with guard_memory() 2196 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2197 address base = stack_red_zone_base() - stack_red_zone_size(); 2198 2199 guarantee(base < stack_base(),"Error calculating stack red zone"); 2200 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2201 2202 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2203 warning("Attempt to guard stack red zone failed."); 2204 } 2205 } 2206 2207 void JavaThread::disable_stack_red_zone() { 2208 // The base notation is from the stacks point of view, growing downward. 2209 // We need to adjust it to work correctly with guard_memory() 2210 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2211 address base = stack_red_zone_base() - stack_red_zone_size(); 2212 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2213 warning("Attempt to unguard stack red zone failed."); 2214 } 2215 } 2216 2217 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2218 // ignore is there is no stack 2219 if (!has_last_Java_frame()) return; 2220 // traverse the stack frames. Starts from top frame. 2221 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2222 frame* fr = fst.current(); 2223 f(fr, fst.register_map()); 2224 } 2225 } 2226 2227 2228 #ifndef PRODUCT 2229 // Deoptimization 2230 // Function for testing deoptimization 2231 void JavaThread::deoptimize() { 2232 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2233 StackFrameStream fst(this, UseBiasedLocking); 2234 bool deopt = false; // Dump stack only if a deopt actually happens. 2235 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2236 // Iterate over all frames in the thread and deoptimize 2237 for(; !fst.is_done(); fst.next()) { 2238 if(fst.current()->can_be_deoptimized()) { 2239 2240 if (only_at) { 2241 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2242 // consists of comma or carriage return separated numbers so 2243 // search for the current bci in that string. 2244 address pc = fst.current()->pc(); 2245 nmethod* nm = (nmethod*) fst.current()->cb(); 2246 ScopeDesc* sd = nm->scope_desc_at( pc); 2247 char buffer[8]; 2248 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2249 size_t len = strlen(buffer); 2250 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2251 while (found != NULL) { 2252 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2253 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2254 // Check that the bci found is bracketed by terminators. 2255 break; 2256 } 2257 found = strstr(found + 1, buffer); 2258 } 2259 if (!found) { 2260 continue; 2261 } 2262 } 2263 2264 if (DebugDeoptimization && !deopt) { 2265 deopt = true; // One-time only print before deopt 2266 tty->print_cr("[BEFORE Deoptimization]"); 2267 trace_frames(); 2268 trace_stack(); 2269 } 2270 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2271 } 2272 } 2273 2274 if (DebugDeoptimization && deopt) { 2275 tty->print_cr("[AFTER Deoptimization]"); 2276 trace_frames(); 2277 } 2278 } 2279 2280 2281 // Make zombies 2282 void JavaThread::make_zombies() { 2283 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2284 if (fst.current()->can_be_deoptimized()) { 2285 // it is a Java nmethod 2286 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2287 nm->make_not_entrant(); 2288 } 2289 } 2290 } 2291 #endif // PRODUCT 2292 2293 2294 void JavaThread::deoptimized_wrt_marked_nmethods() { 2295 if (!has_last_Java_frame()) return; 2296 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2297 StackFrameStream fst(this, UseBiasedLocking); 2298 for(; !fst.is_done(); fst.next()) { 2299 if (fst.current()->should_be_deoptimized()) { 2300 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2301 } 2302 } 2303 } 2304 2305 2306 // GC support 2307 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2308 2309 void JavaThread::gc_epilogue() { 2310 frames_do(frame_gc_epilogue); 2311 } 2312 2313 2314 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2315 2316 void JavaThread::gc_prologue() { 2317 frames_do(frame_gc_prologue); 2318 } 2319 2320 2321 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 2322 // Flush deferred store-barriers, if any, associated with 2323 // initializing stores done by this JavaThread in the current epoch. 2324 Universe::heap()->flush_deferred_store_barrier(this); 2325 2326 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2327 // since there may be more than one thread using each ThreadProfiler. 2328 2329 // Traverse the GCHandles 2330 Thread::oops_do(f, cf); 2331 2332 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2333 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2334 2335 if (has_last_Java_frame()) { 2336 2337 // Traverse the privileged stack 2338 if (_privileged_stack_top != NULL) { 2339 _privileged_stack_top->oops_do(f); 2340 } 2341 2342 // traverse the registered growable array 2343 if (_array_for_gc != NULL) { 2344 for (int index = 0; index < _array_for_gc->length(); index++) { 2345 f->do_oop(_array_for_gc->adr_at(index)); 2346 } 2347 } 2348 2349 // Traverse the monitor chunks 2350 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2351 chunk->oops_do(f); 2352 } 2353 2354 // Traverse the execution stack 2355 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2356 fst.current()->oops_do(f, cf, fst.register_map()); 2357 } 2358 } 2359 2360 // callee_target is never live across a gc point so NULL it here should 2361 // it still contain a methdOop. 2362 2363 set_callee_target(NULL); 2364 2365 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2366 // If we have deferred set_locals there might be oops waiting to be 2367 // written 2368 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2369 if (list != NULL) { 2370 for (int i = 0; i < list->length(); i++) { 2371 list->at(i)->oops_do(f); 2372 } 2373 } 2374 2375 // Traverse instance variables at the end since the GC may be moving things 2376 // around using this function 2377 f->do_oop((oop*) &_threadObj); 2378 f->do_oop((oop*) &_vm_result); 2379 f->do_oop((oop*) &_vm_result_2); 2380 f->do_oop((oop*) &_exception_oop); 2381 f->do_oop((oop*) &_pending_async_exception); 2382 2383 if (jvmti_thread_state() != NULL) { 2384 jvmti_thread_state()->oops_do(f); 2385 } 2386 } 2387 2388 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2389 Thread::nmethods_do(cf); // (super method is a no-op) 2390 2391 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2392 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2393 2394 if (has_last_Java_frame()) { 2395 // Traverse the execution stack 2396 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2397 fst.current()->nmethods_do(cf); 2398 } 2399 } 2400 } 2401 2402 // Printing 2403 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2404 switch (_thread_state) { 2405 case _thread_uninitialized: return "_thread_uninitialized"; 2406 case _thread_new: return "_thread_new"; 2407 case _thread_new_trans: return "_thread_new_trans"; 2408 case _thread_in_native: return "_thread_in_native"; 2409 case _thread_in_native_trans: return "_thread_in_native_trans"; 2410 case _thread_in_vm: return "_thread_in_vm"; 2411 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2412 case _thread_in_Java: return "_thread_in_Java"; 2413 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2414 case _thread_blocked: return "_thread_blocked"; 2415 case _thread_blocked_trans: return "_thread_blocked_trans"; 2416 default: return "unknown thread state"; 2417 } 2418 } 2419 2420 #ifndef PRODUCT 2421 void JavaThread::print_thread_state_on(outputStream *st) const { 2422 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2423 }; 2424 void JavaThread::print_thread_state() const { 2425 print_thread_state_on(tty); 2426 }; 2427 #endif // PRODUCT 2428 2429 // Called by Threads::print() for VM_PrintThreads operation 2430 void JavaThread::print_on(outputStream *st) const { 2431 st->print("\"%s\" ", get_thread_name()); 2432 oop thread_oop = threadObj(); 2433 if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2434 Thread::print_on(st); 2435 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2436 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2437 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2438 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2439 } 2440 #ifndef PRODUCT 2441 print_thread_state_on(st); 2442 _safepoint_state->print_on(st); 2443 #endif // PRODUCT 2444 } 2445 2446 // Called by fatal error handler. The difference between this and 2447 // JavaThread::print() is that we can't grab lock or allocate memory. 2448 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2449 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2450 oop thread_obj = threadObj(); 2451 if (thread_obj != NULL) { 2452 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2453 } 2454 st->print(" ["); 2455 st->print("%s", _get_thread_state_name(_thread_state)); 2456 if (osthread()) { 2457 st->print(", id=%d", osthread()->thread_id()); 2458 } 2459 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2460 _stack_base - _stack_size, _stack_base); 2461 st->print("]"); 2462 return; 2463 } 2464 2465 // Verification 2466 2467 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2468 2469 void JavaThread::verify() { 2470 // Verify oops in the thread. 2471 oops_do(&VerifyOopClosure::verify_oop, NULL); 2472 2473 // Verify the stack frames. 2474 frames_do(frame_verify); 2475 } 2476 2477 // CR 6300358 (sub-CR 2137150) 2478 // Most callers of this method assume that it can't return NULL but a 2479 // thread may not have a name whilst it is in the process of attaching to 2480 // the VM - see CR 6412693, and there are places where a JavaThread can be 2481 // seen prior to having it's threadObj set (eg JNI attaching threads and 2482 // if vm exit occurs during initialization). These cases can all be accounted 2483 // for such that this method never returns NULL. 2484 const char* JavaThread::get_thread_name() const { 2485 #ifdef ASSERT 2486 // early safepoints can hit while current thread does not yet have TLS 2487 if (!SafepointSynchronize::is_at_safepoint()) { 2488 Thread *cur = Thread::current(); 2489 if (!(cur->is_Java_thread() && cur == this)) { 2490 // Current JavaThreads are allowed to get their own name without 2491 // the Threads_lock. 2492 assert_locked_or_safepoint(Threads_lock); 2493 } 2494 } 2495 #endif // ASSERT 2496 return get_thread_name_string(); 2497 } 2498 2499 // Returns a non-NULL representation of this thread's name, or a suitable 2500 // descriptive string if there is no set name 2501 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2502 const char* name_str; 2503 oop thread_obj = threadObj(); 2504 if (thread_obj != NULL) { 2505 typeArrayOop name = java_lang_Thread::name(thread_obj); 2506 if (name != NULL) { 2507 if (buf == NULL) { 2508 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2509 } 2510 else { 2511 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2512 } 2513 } 2514 else if (is_attaching()) { // workaround for 6412693 - see 6404306 2515 name_str = "<no-name - thread is attaching>"; 2516 } 2517 else { 2518 name_str = Thread::name(); 2519 } 2520 } 2521 else { 2522 name_str = Thread::name(); 2523 } 2524 assert(name_str != NULL, "unexpected NULL thread name"); 2525 return name_str; 2526 } 2527 2528 2529 const char* JavaThread::get_threadgroup_name() const { 2530 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2531 oop thread_obj = threadObj(); 2532 if (thread_obj != NULL) { 2533 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2534 if (thread_group != NULL) { 2535 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2536 // ThreadGroup.name can be null 2537 if (name != NULL) { 2538 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2539 return str; 2540 } 2541 } 2542 } 2543 return NULL; 2544 } 2545 2546 const char* JavaThread::get_parent_name() const { 2547 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2548 oop thread_obj = threadObj(); 2549 if (thread_obj != NULL) { 2550 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2551 if (thread_group != NULL) { 2552 oop parent = java_lang_ThreadGroup::parent(thread_group); 2553 if (parent != NULL) { 2554 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2555 // ThreadGroup.name can be null 2556 if (name != NULL) { 2557 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2558 return str; 2559 } 2560 } 2561 } 2562 } 2563 return NULL; 2564 } 2565 2566 ThreadPriority JavaThread::java_priority() const { 2567 oop thr_oop = threadObj(); 2568 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2569 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2570 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2571 return priority; 2572 } 2573 2574 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2575 2576 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2577 // Link Java Thread object <-> C++ Thread 2578 2579 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2580 // and put it into a new Handle. The Handle "thread_oop" can then 2581 // be used to pass the C++ thread object to other methods. 2582 2583 // Set the Java level thread object (jthread) field of the 2584 // new thread (a JavaThread *) to C++ thread object using the 2585 // "thread_oop" handle. 2586 2587 // Set the thread field (a JavaThread *) of the 2588 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 2589 2590 Handle thread_oop(Thread::current(), 2591 JNIHandles::resolve_non_null(jni_thread)); 2592 assert(instanceKlass::cast(thread_oop->klass())->is_linked(), 2593 "must be initialized"); 2594 set_threadObj(thread_oop()); 2595 java_lang_Thread::set_thread(thread_oop(), this); 2596 2597 if (prio == NoPriority) { 2598 prio = java_lang_Thread::priority(thread_oop()); 2599 assert(prio != NoPriority, "A valid priority should be present"); 2600 } 2601 2602 // Push the Java priority down to the native thread; needs Threads_lock 2603 Thread::set_priority(this, prio); 2604 2605 // Add the new thread to the Threads list and set it in motion. 2606 // We must have threads lock in order to call Threads::add. 2607 // It is crucial that we do not block before the thread is 2608 // added to the Threads list for if a GC happens, then the java_thread oop 2609 // will not be visited by GC. 2610 Threads::add(this); 2611 } 2612 2613 oop JavaThread::current_park_blocker() { 2614 // Support for JSR-166 locks 2615 oop thread_oop = threadObj(); 2616 if (thread_oop != NULL && 2617 JDK_Version::current().supports_thread_park_blocker()) { 2618 return java_lang_Thread::park_blocker(thread_oop); 2619 } 2620 return NULL; 2621 } 2622 2623 2624 void JavaThread::print_stack_on(outputStream* st) { 2625 if (!has_last_Java_frame()) return; 2626 ResourceMark rm; 2627 HandleMark hm; 2628 2629 RegisterMap reg_map(this); 2630 vframe* start_vf = last_java_vframe(®_map); 2631 int count = 0; 2632 for (vframe* f = start_vf; f; f = f->sender() ) { 2633 if (f->is_java_frame()) { 2634 javaVFrame* jvf = javaVFrame::cast(f); 2635 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 2636 2637 // Print out lock information 2638 if (JavaMonitorsInStackTrace) { 2639 jvf->print_lock_info_on(st, count); 2640 } 2641 } else { 2642 // Ignore non-Java frames 2643 } 2644 2645 // Bail-out case for too deep stacks 2646 count++; 2647 if (MaxJavaStackTraceDepth == count) return; 2648 } 2649 } 2650 2651 2652 // JVMTI PopFrame support 2653 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 2654 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 2655 if (in_bytes(size_in_bytes) != 0) { 2656 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes)); 2657 _popframe_preserved_args_size = in_bytes(size_in_bytes); 2658 Copy::conjoint_bytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 2659 } 2660 } 2661 2662 void* JavaThread::popframe_preserved_args() { 2663 return _popframe_preserved_args; 2664 } 2665 2666 ByteSize JavaThread::popframe_preserved_args_size() { 2667 return in_ByteSize(_popframe_preserved_args_size); 2668 } 2669 2670 WordSize JavaThread::popframe_preserved_args_size_in_words() { 2671 int sz = in_bytes(popframe_preserved_args_size()); 2672 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 2673 return in_WordSize(sz / wordSize); 2674 } 2675 2676 void JavaThread::popframe_free_preserved_args() { 2677 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 2678 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args); 2679 _popframe_preserved_args = NULL; 2680 _popframe_preserved_args_size = 0; 2681 } 2682 2683 #ifndef PRODUCT 2684 2685 void JavaThread::trace_frames() { 2686 tty->print_cr("[Describe stack]"); 2687 int frame_no = 1; 2688 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2689 tty->print(" %d. ", frame_no++); 2690 fst.current()->print_value_on(tty,this); 2691 tty->cr(); 2692 } 2693 } 2694 2695 2696 void JavaThread::trace_stack_from(vframe* start_vf) { 2697 ResourceMark rm; 2698 int vframe_no = 1; 2699 for (vframe* f = start_vf; f; f = f->sender() ) { 2700 if (f->is_java_frame()) { 2701 javaVFrame::cast(f)->print_activation(vframe_no++); 2702 } else { 2703 f->print(); 2704 } 2705 if (vframe_no > StackPrintLimit) { 2706 tty->print_cr("...<more frames>..."); 2707 return; 2708 } 2709 } 2710 } 2711 2712 2713 void JavaThread::trace_stack() { 2714 if (!has_last_Java_frame()) return; 2715 ResourceMark rm; 2716 HandleMark hm; 2717 RegisterMap reg_map(this); 2718 trace_stack_from(last_java_vframe(®_map)); 2719 } 2720 2721 2722 #endif // PRODUCT 2723 2724 2725 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 2726 assert(reg_map != NULL, "a map must be given"); 2727 frame f = last_frame(); 2728 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 2729 if (vf->is_java_frame()) return javaVFrame::cast(vf); 2730 } 2731 return NULL; 2732 } 2733 2734 2735 klassOop JavaThread::security_get_caller_class(int depth) { 2736 vframeStream vfst(this); 2737 vfst.security_get_caller_frame(depth); 2738 if (!vfst.at_end()) { 2739 return vfst.method()->method_holder(); 2740 } 2741 return NULL; 2742 } 2743 2744 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 2745 assert(thread->is_Compiler_thread(), "must be compiler thread"); 2746 CompileBroker::compiler_thread_loop(); 2747 } 2748 2749 // Create a CompilerThread 2750 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 2751 : JavaThread(&compiler_thread_entry) { 2752 _env = NULL; 2753 _log = NULL; 2754 _task = NULL; 2755 _queue = queue; 2756 _counters = counters; 2757 2758 #ifndef PRODUCT 2759 _ideal_graph_printer = NULL; 2760 #endif 2761 } 2762 2763 2764 // ======= Threads ======== 2765 2766 // The Threads class links together all active threads, and provides 2767 // operations over all threads. It is protected by its own Mutex 2768 // lock, which is also used in other contexts to protect thread 2769 // operations from having the thread being operated on from exiting 2770 // and going away unexpectedly (e.g., safepoint synchronization) 2771 2772 JavaThread* Threads::_thread_list = NULL; 2773 int Threads::_number_of_threads = 0; 2774 int Threads::_number_of_non_daemon_threads = 0; 2775 int Threads::_return_code = 0; 2776 size_t JavaThread::_stack_size_at_create = 0; 2777 2778 // All JavaThreads 2779 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 2780 2781 void os_stream(); 2782 2783 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 2784 void Threads::threads_do(ThreadClosure* tc) { 2785 assert_locked_or_safepoint(Threads_lock); 2786 // ALL_JAVA_THREADS iterates through all JavaThreads 2787 ALL_JAVA_THREADS(p) { 2788 tc->do_thread(p); 2789 } 2790 // Someday we could have a table or list of all non-JavaThreads. 2791 // For now, just manually iterate through them. 2792 tc->do_thread(VMThread::vm_thread()); 2793 Universe::heap()->gc_threads_do(tc); 2794 WatcherThread *wt = WatcherThread::watcher_thread(); 2795 // Strictly speaking, the following NULL check isn't sufficient to make sure 2796 // the data for WatcherThread is still valid upon being examined. However, 2797 // considering that WatchThread terminates when the VM is on the way to 2798 // exit at safepoint, the chance of the above is extremely small. The right 2799 // way to prevent termination of WatcherThread would be to acquire 2800 // Terminator_lock, but we can't do that without violating the lock rank 2801 // checking in some cases. 2802 if (wt != NULL) 2803 tc->do_thread(wt); 2804 2805 // If CompilerThreads ever become non-JavaThreads, add them here 2806 } 2807 2808 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 2809 2810 extern void JDK_Version_init(); 2811 2812 // Check version 2813 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 2814 2815 // Initialize the output stream module 2816 ostream_init(); 2817 2818 // Process java launcher properties. 2819 Arguments::process_sun_java_launcher_properties(args); 2820 2821 // Initialize the os module before using TLS 2822 os::init(); 2823 2824 // Initialize system properties. 2825 Arguments::init_system_properties(); 2826 2827 // So that JDK version can be used as a discrimintor when parsing arguments 2828 JDK_Version_init(); 2829 2830 // Parse arguments 2831 jint parse_result = Arguments::parse(args); 2832 if (parse_result != JNI_OK) return parse_result; 2833 2834 if (PauseAtStartup) { 2835 os::pause(); 2836 } 2837 2838 HS_DTRACE_PROBE(hotspot, vm__init__begin); 2839 2840 // Record VM creation timing statistics 2841 TraceVmCreationTime create_vm_timer; 2842 create_vm_timer.start(); 2843 2844 // Timing (must come after argument parsing) 2845 TraceTime timer("Create VM", TraceStartupTime); 2846 2847 // Initialize the os module after parsing the args 2848 jint os_init_2_result = os::init_2(); 2849 if (os_init_2_result != JNI_OK) return os_init_2_result; 2850 2851 // Initialize output stream logging 2852 ostream_init_log(); 2853 2854 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 2855 // Must be before create_vm_init_agents() 2856 if (Arguments::init_libraries_at_startup()) { 2857 convert_vm_init_libraries_to_agents(); 2858 } 2859 2860 // Launch -agentlib/-agentpath and converted -Xrun agents 2861 if (Arguments::init_agents_at_startup()) { 2862 create_vm_init_agents(); 2863 } 2864 2865 // Initialize Threads state 2866 _thread_list = NULL; 2867 _number_of_threads = 0; 2868 _number_of_non_daemon_threads = 0; 2869 2870 // Initialize TLS 2871 ThreadLocalStorage::init(); 2872 2873 // Initialize global data structures and create system classes in heap 2874 vm_init_globals(); 2875 2876 // Attach the main thread to this os thread 2877 JavaThread* main_thread = new JavaThread(); 2878 main_thread->set_thread_state(_thread_in_vm); 2879 // must do this before set_active_handles and initialize_thread_local_storage 2880 // Note: on solaris initialize_thread_local_storage() will (indirectly) 2881 // change the stack size recorded here to one based on the java thread 2882 // stacksize. This adjusted size is what is used to figure the placement 2883 // of the guard pages. 2884 main_thread->record_stack_base_and_size(); 2885 main_thread->initialize_thread_local_storage(); 2886 2887 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 2888 2889 if (!main_thread->set_as_starting_thread()) { 2890 vm_shutdown_during_initialization( 2891 "Failed necessary internal allocation. Out of swap space"); 2892 delete main_thread; 2893 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 2894 return JNI_ENOMEM; 2895 } 2896 2897 // Enable guard page *after* os::create_main_thread(), otherwise it would 2898 // crash Linux VM, see notes in os_linux.cpp. 2899 main_thread->create_stack_guard_pages(); 2900 2901 // Initialize Java-Leve synchronization subsystem 2902 ObjectSynchronizer::Initialize() ; 2903 2904 // Initialize global modules 2905 jint status = init_globals(); 2906 if (status != JNI_OK) { 2907 delete main_thread; 2908 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 2909 return status; 2910 } 2911 2912 HandleMark hm; 2913 2914 { MutexLocker mu(Threads_lock); 2915 Threads::add(main_thread); 2916 } 2917 2918 // Any JVMTI raw monitors entered in onload will transition into 2919 // real raw monitor. VM is setup enough here for raw monitor enter. 2920 JvmtiExport::transition_pending_onload_raw_monitors(); 2921 2922 if (VerifyBeforeGC && 2923 Universe::heap()->total_collections() >= VerifyGCStartAt) { 2924 Universe::heap()->prepare_for_verify(); 2925 Universe::verify(); // make sure we're starting with a clean slate 2926 } 2927 2928 // Create the VMThread 2929 { TraceTime timer("Start VMThread", TraceStartupTime); 2930 VMThread::create(); 2931 Thread* vmthread = VMThread::vm_thread(); 2932 2933 if (!os::create_thread(vmthread, os::vm_thread)) 2934 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 2935 2936 // Wait for the VM thread to become ready, and VMThread::run to initialize 2937 // Monitors can have spurious returns, must always check another state flag 2938 { 2939 MutexLocker ml(Notify_lock); 2940 os::start_thread(vmthread); 2941 while (vmthread->active_handles() == NULL) { 2942 Notify_lock->wait(); 2943 } 2944 } 2945 } 2946 2947 assert (Universe::is_fully_initialized(), "not initialized"); 2948 EXCEPTION_MARK; 2949 2950 // At this point, the Universe is initialized, but we have not executed 2951 // any byte code. Now is a good time (the only time) to dump out the 2952 // internal state of the JVM for sharing. 2953 2954 if (DumpSharedSpaces) { 2955 Universe::heap()->preload_and_dump(CHECK_0); 2956 ShouldNotReachHere(); 2957 } 2958 2959 // Always call even when there are not JVMTI environments yet, since environments 2960 // may be attached late and JVMTI must track phases of VM execution 2961 JvmtiExport::enter_start_phase(); 2962 2963 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 2964 JvmtiExport::post_vm_start(); 2965 2966 { 2967 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 2968 2969 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 2970 create_vm_init_libraries(); 2971 } 2972 2973 if (InitializeJavaLangString) { 2974 initialize_class(vmSymbolHandles::java_lang_String(), CHECK_0); 2975 } else { 2976 warning("java.lang.String not initialized"); 2977 } 2978 2979 if (AggressiveOpts) { 2980 { 2981 // Forcibly initialize java/util/HashMap and mutate the private 2982 // static final "frontCacheEnabled" field before we start creating instances 2983 #ifdef ASSERT 2984 klassOop tmp_k = SystemDictionary::find(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0); 2985 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet"); 2986 #endif 2987 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0); 2988 KlassHandle k = KlassHandle(THREAD, k_o); 2989 guarantee(k.not_null(), "Must find java/util/HashMap"); 2990 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 2991 ik->initialize(CHECK_0); 2992 fieldDescriptor fd; 2993 // Possible we might not find this field; if so, don't break 2994 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 2995 k()->bool_field_put(fd.offset(), true); 2996 } 2997 } 2998 2999 if (UseStringCache) { 3000 // Forcibly initialize java/lang/StringValue and mutate the private 3001 // static final "stringCacheEnabled" field before we start creating instances 3002 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_StringValue(), Handle(), Handle(), CHECK_0); 3003 // Possible that StringValue isn't present: if so, silently don't break 3004 if (k_o != NULL) { 3005 KlassHandle k = KlassHandle(THREAD, k_o); 3006 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3007 ik->initialize(CHECK_0); 3008 fieldDescriptor fd; 3009 // Possible we might not find this field: if so, silently don't break 3010 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3011 k()->bool_field_put(fd.offset(), true); 3012 } 3013 } 3014 } 3015 } 3016 3017 // Initialize java_lang.System (needed before creating the thread) 3018 if (InitializeJavaLangSystem) { 3019 initialize_class(vmSymbolHandles::java_lang_System(), CHECK_0); 3020 initialize_class(vmSymbolHandles::java_lang_ThreadGroup(), CHECK_0); 3021 Handle thread_group = create_initial_thread_group(CHECK_0); 3022 Universe::set_main_thread_group(thread_group()); 3023 initialize_class(vmSymbolHandles::java_lang_Thread(), CHECK_0); 3024 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0); 3025 main_thread->set_threadObj(thread_object); 3026 // Set thread status to running since main thread has 3027 // been started and running. 3028 java_lang_Thread::set_thread_status(thread_object, 3029 java_lang_Thread::RUNNABLE); 3030 3031 // The VM preresolve methods to these classes. Make sure that get initialized 3032 initialize_class(vmSymbolHandles::java_lang_reflect_Method(), CHECK_0); 3033 initialize_class(vmSymbolHandles::java_lang_ref_Finalizer(), CHECK_0); 3034 // The VM creates & returns objects of this class. Make sure it's initialized. 3035 initialize_class(vmSymbolHandles::java_lang_Class(), CHECK_0); 3036 call_initializeSystemClass(CHECK_0); 3037 } else { 3038 warning("java.lang.System not initialized"); 3039 } 3040 3041 // an instance of OutOfMemory exception has been allocated earlier 3042 if (InitializeJavaLangExceptionsErrors) { 3043 initialize_class(vmSymbolHandles::java_lang_OutOfMemoryError(), CHECK_0); 3044 initialize_class(vmSymbolHandles::java_lang_NullPointerException(), CHECK_0); 3045 initialize_class(vmSymbolHandles::java_lang_ClassCastException(), CHECK_0); 3046 initialize_class(vmSymbolHandles::java_lang_ArrayStoreException(), CHECK_0); 3047 initialize_class(vmSymbolHandles::java_lang_ArithmeticException(), CHECK_0); 3048 initialize_class(vmSymbolHandles::java_lang_StackOverflowError(), CHECK_0); 3049 initialize_class(vmSymbolHandles::java_lang_IllegalMonitorStateException(), CHECK_0); 3050 } else { 3051 warning("java.lang.OutOfMemoryError has not been initialized"); 3052 warning("java.lang.NullPointerException has not been initialized"); 3053 warning("java.lang.ClassCastException has not been initialized"); 3054 warning("java.lang.ArrayStoreException has not been initialized"); 3055 warning("java.lang.ArithmeticException has not been initialized"); 3056 warning("java.lang.StackOverflowError has not been initialized"); 3057 } 3058 } 3059 3060 // See : bugid 4211085. 3061 // Background : the static initializer of java.lang.Compiler tries to read 3062 // property"java.compiler" and read & write property "java.vm.info". 3063 // When a security manager is installed through the command line 3064 // option "-Djava.security.manager", the above properties are not 3065 // readable and the static initializer for java.lang.Compiler fails 3066 // resulting in a NoClassDefFoundError. This can happen in any 3067 // user code which calls methods in java.lang.Compiler. 3068 // Hack : the hack is to pre-load and initialize this class, so that only 3069 // system domains are on the stack when the properties are read. 3070 // Currently even the AWT code has calls to methods in java.lang.Compiler. 3071 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT. 3072 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and 3073 // read and write"java.vm.info" in the default policy file. See bugid 4211383 3074 // Once that is done, we should remove this hack. 3075 initialize_class(vmSymbolHandles::java_lang_Compiler(), CHECK_0); 3076 3077 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to 3078 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot 3079 // compiler does not get loaded through java.lang.Compiler). "java -version" with the 3080 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here. 3081 // This should also be taken out as soon as 4211383 gets fixed. 3082 reset_vm_info_property(CHECK_0); 3083 3084 quicken_jni_functions(); 3085 3086 // Set flag that basic initialization has completed. Used by exceptions and various 3087 // debug stuff, that does not work until all basic classes have been initialized. 3088 set_init_completed(); 3089 3090 HS_DTRACE_PROBE(hotspot, vm__init__end); 3091 3092 // record VM initialization completion time 3093 Management::record_vm_init_completed(); 3094 3095 // Compute system loader. Note that this has to occur after set_init_completed, since 3096 // valid exceptions may be thrown in the process. 3097 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3098 // set_init_completed has just been called, causing exceptions not to be shortcut 3099 // anymore. We call vm_exit_during_initialization directly instead. 3100 SystemDictionary::compute_java_system_loader(THREAD); 3101 if (HAS_PENDING_EXCEPTION) { 3102 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3103 } 3104 3105 #ifndef SERIALGC 3106 // Support for ConcurrentMarkSweep. This should be cleaned up 3107 // and better encapsulated. The ugly nested if test would go away 3108 // once things are properly refactored. XXX YSR 3109 if (UseConcMarkSweepGC || UseG1GC) { 3110 if (UseConcMarkSweepGC) { 3111 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD); 3112 } else { 3113 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD); 3114 } 3115 if (HAS_PENDING_EXCEPTION) { 3116 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3117 } 3118 } 3119 #endif // SERIALGC 3120 3121 // Always call even when there are not JVMTI environments yet, since environments 3122 // may be attached late and JVMTI must track phases of VM execution 3123 JvmtiExport::enter_live_phase(); 3124 3125 // Signal Dispatcher needs to be started before VMInit event is posted 3126 os::signal_init(); 3127 3128 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3129 if (!DisableAttachMechanism) { 3130 if (StartAttachListener || AttachListener::init_at_startup()) { 3131 AttachListener::init(); 3132 } 3133 } 3134 3135 // Launch -Xrun agents 3136 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3137 // back-end can launch with -Xdebug -Xrunjdwp. 3138 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3139 create_vm_init_libraries(); 3140 } 3141 3142 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3143 JvmtiExport::post_vm_initialized(); 3144 3145 Chunk::start_chunk_pool_cleaner_task(); 3146 3147 // initialize compiler(s) 3148 CompileBroker::compilation_init(); 3149 3150 Management::initialize(THREAD); 3151 if (HAS_PENDING_EXCEPTION) { 3152 // management agent fails to start possibly due to 3153 // configuration problem and is responsible for printing 3154 // stack trace if appropriate. Simply exit VM. 3155 vm_exit(1); 3156 } 3157 3158 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3159 if (Arguments::has_alloc_profile()) AllocationProfiler::engage(); 3160 if (MemProfiling) MemProfiler::engage(); 3161 StatSampler::engage(); 3162 if (CheckJNICalls) JniPeriodicChecker::engage(); 3163 3164 BiasedLocking::init(); 3165 3166 3167 // Start up the WatcherThread if there are any periodic tasks 3168 // NOTE: All PeriodicTasks should be registered by now. If they 3169 // aren't, late joiners might appear to start slowly (we might 3170 // take a while to process their first tick). 3171 if (PeriodicTask::num_tasks() > 0) { 3172 WatcherThread::start(); 3173 } 3174 3175 create_vm_timer.end(); 3176 return JNI_OK; 3177 } 3178 3179 // type for the Agent_OnLoad and JVM_OnLoad entry points 3180 extern "C" { 3181 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3182 } 3183 // Find a command line agent library and return its entry point for 3184 // -agentlib: -agentpath: -Xrun 3185 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3186 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3187 OnLoadEntry_t on_load_entry = NULL; 3188 void *library = agent->os_lib(); // check if we have looked it up before 3189 3190 if (library == NULL) { 3191 char buffer[JVM_MAXPATHLEN]; 3192 char ebuf[1024]; 3193 const char *name = agent->name(); 3194 3195 if (agent->is_absolute_path()) { 3196 library = hpi::dll_load(name, ebuf, sizeof ebuf); 3197 if (library == NULL) { 3198 // If we can't find the agent, exit. 3199 vm_exit_during_initialization("Could not find agent library in absolute path", name); 3200 } 3201 } else { 3202 // Try to load the agent from the standard dll directory 3203 hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name); 3204 library = hpi::dll_load(buffer, ebuf, sizeof ebuf); 3205 #ifdef KERNEL 3206 // Download instrument dll 3207 if (library == NULL && strcmp(name, "instrument") == 0) { 3208 char *props = Arguments::get_kernel_properties(); 3209 char *home = Arguments::get_java_home(); 3210 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false" 3211 " sun.jkernel.DownloadManager -download client_jvm"; 3212 int length = strlen(props) + strlen(home) + strlen(fmt) + 1; 3213 char *cmd = AllocateHeap(length); 3214 jio_snprintf(cmd, length, fmt, home, props); 3215 int status = os::fork_and_exec(cmd); 3216 FreeHeap(props); 3217 FreeHeap(cmd); 3218 if (status == -1) { 3219 warning(cmd); 3220 vm_exit_during_initialization("fork_and_exec failed: %s", 3221 strerror(errno)); 3222 } 3223 // when this comes back the instrument.dll should be where it belongs. 3224 library = hpi::dll_load(buffer, ebuf, sizeof ebuf); 3225 } 3226 #endif // KERNEL 3227 if (library == NULL) { // Try the local directory 3228 char ns[1] = {0}; 3229 hpi::dll_build_name(buffer, sizeof(buffer), ns, name); 3230 library = hpi::dll_load(buffer, ebuf, sizeof ebuf); 3231 if (library == NULL) { 3232 // If we can't find the agent, exit. 3233 vm_exit_during_initialization("Could not find agent library on the library path or in the local directory", name); 3234 } 3235 } 3236 } 3237 agent->set_os_lib(library); 3238 } 3239 3240 // Find the OnLoad function. 3241 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) { 3242 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, hpi::dll_lookup(library, on_load_symbols[symbol_index])); 3243 if (on_load_entry != NULL) break; 3244 } 3245 return on_load_entry; 3246 } 3247 3248 // Find the JVM_OnLoad entry point 3249 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3250 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3251 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3252 } 3253 3254 // Find the Agent_OnLoad entry point 3255 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3256 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3257 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3258 } 3259 3260 // For backwards compatibility with -Xrun 3261 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3262 // treated like -agentpath: 3263 // Must be called before agent libraries are created 3264 void Threads::convert_vm_init_libraries_to_agents() { 3265 AgentLibrary* agent; 3266 AgentLibrary* next; 3267 3268 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3269 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3270 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3271 3272 // If there is an JVM_OnLoad function it will get called later, 3273 // otherwise see if there is an Agent_OnLoad 3274 if (on_load_entry == NULL) { 3275 on_load_entry = lookup_agent_on_load(agent); 3276 if (on_load_entry != NULL) { 3277 // switch it to the agent list -- so that Agent_OnLoad will be called, 3278 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3279 Arguments::convert_library_to_agent(agent); 3280 } else { 3281 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3282 } 3283 } 3284 } 3285 } 3286 3287 // Create agents for -agentlib: -agentpath: and converted -Xrun 3288 // Invokes Agent_OnLoad 3289 // Called very early -- before JavaThreads exist 3290 void Threads::create_vm_init_agents() { 3291 extern struct JavaVM_ main_vm; 3292 AgentLibrary* agent; 3293 3294 JvmtiExport::enter_onload_phase(); 3295 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3296 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3297 3298 if (on_load_entry != NULL) { 3299 // Invoke the Agent_OnLoad function 3300 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3301 if (err != JNI_OK) { 3302 vm_exit_during_initialization("agent library failed to init", agent->name()); 3303 } 3304 } else { 3305 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3306 } 3307 } 3308 JvmtiExport::enter_primordial_phase(); 3309 } 3310 3311 extern "C" { 3312 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3313 } 3314 3315 void Threads::shutdown_vm_agents() { 3316 // Send any Agent_OnUnload notifications 3317 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3318 extern struct JavaVM_ main_vm; 3319 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3320 3321 // Find the Agent_OnUnload function. 3322 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) { 3323 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3324 hpi::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index])); 3325 3326 // Invoke the Agent_OnUnload function 3327 if (unload_entry != NULL) { 3328 JavaThread* thread = JavaThread::current(); 3329 ThreadToNativeFromVM ttn(thread); 3330 HandleMark hm(thread); 3331 (*unload_entry)(&main_vm); 3332 break; 3333 } 3334 } 3335 } 3336 } 3337 3338 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3339 // Invokes JVM_OnLoad 3340 void Threads::create_vm_init_libraries() { 3341 extern struct JavaVM_ main_vm; 3342 AgentLibrary* agent; 3343 3344 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3345 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3346 3347 if (on_load_entry != NULL) { 3348 // Invoke the JVM_OnLoad function 3349 JavaThread* thread = JavaThread::current(); 3350 ThreadToNativeFromVM ttn(thread); 3351 HandleMark hm(thread); 3352 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3353 if (err != JNI_OK) { 3354 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3355 } 3356 } else { 3357 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3358 } 3359 } 3360 } 3361 3362 // Last thread running calls java.lang.Shutdown.shutdown() 3363 void JavaThread::invoke_shutdown_hooks() { 3364 HandleMark hm(this); 3365 3366 // We could get here with a pending exception, if so clear it now. 3367 if (this->has_pending_exception()) { 3368 this->clear_pending_exception(); 3369 } 3370 3371 EXCEPTION_MARK; 3372 klassOop k = 3373 SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_Shutdown(), 3374 THREAD); 3375 if (k != NULL) { 3376 // SystemDictionary::resolve_or_null will return null if there was 3377 // an exception. If we cannot load the Shutdown class, just don't 3378 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3379 // and finalizers (if runFinalizersOnExit is set) won't be run. 3380 // Note that if a shutdown hook was registered or runFinalizersOnExit 3381 // was called, the Shutdown class would have already been loaded 3382 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3383 instanceKlassHandle shutdown_klass (THREAD, k); 3384 JavaValue result(T_VOID); 3385 JavaCalls::call_static(&result, 3386 shutdown_klass, 3387 vmSymbolHandles::shutdown_method_name(), 3388 vmSymbolHandles::void_method_signature(), 3389 THREAD); 3390 } 3391 CLEAR_PENDING_EXCEPTION; 3392 } 3393 3394 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3395 // the program falls off the end of main(). Another VM exit path is through 3396 // vm_exit() when the program calls System.exit() to return a value or when 3397 // there is a serious error in VM. The two shutdown paths are not exactly 3398 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 3399 // and VM_Exit op at VM level. 3400 // 3401 // Shutdown sequence: 3402 // + Wait until we are the last non-daemon thread to execute 3403 // <-- every thing is still working at this moment --> 3404 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3405 // shutdown hooks, run finalizers if finalization-on-exit 3406 // + Call before_exit(), prepare for VM exit 3407 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3408 // currently the only user of this mechanism is File.deleteOnExit()) 3409 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 3410 // post thread end and vm death events to JVMTI, 3411 // stop signal thread 3412 // + Call JavaThread::exit(), it will: 3413 // > release JNI handle blocks, remove stack guard pages 3414 // > remove this thread from Threads list 3415 // <-- no more Java code from this thread after this point --> 3416 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3417 // the compiler threads at safepoint 3418 // <-- do not use anything that could get blocked by Safepoint --> 3419 // + Disable tracing at JNI/JVM barriers 3420 // + Set _vm_exited flag for threads that are still running native code 3421 // + Delete this thread 3422 // + Call exit_globals() 3423 // > deletes tty 3424 // > deletes PerfMemory resources 3425 // + Return to caller 3426 3427 bool Threads::destroy_vm() { 3428 JavaThread* thread = JavaThread::current(); 3429 3430 // Wait until we are the last non-daemon thread to execute 3431 { MutexLocker nu(Threads_lock); 3432 while (Threads::number_of_non_daemon_threads() > 1 ) 3433 // This wait should make safepoint checks, wait without a timeout, 3434 // and wait as a suspend-equivalent condition. 3435 // 3436 // Note: If the FlatProfiler is running and this thread is waiting 3437 // for another non-daemon thread to finish, then the FlatProfiler 3438 // is waiting for the external suspend request on this thread to 3439 // complete. wait_for_ext_suspend_completion() will eventually 3440 // timeout, but that takes time. Making this wait a suspend- 3441 // equivalent condition solves that timeout problem. 3442 // 3443 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3444 Mutex::_as_suspend_equivalent_flag); 3445 } 3446 3447 // Hang forever on exit if we are reporting an error. 3448 if (ShowMessageBoxOnError && is_error_reported()) { 3449 os::infinite_sleep(); 3450 } 3451 3452 if (JDK_Version::is_jdk12x_version()) { 3453 // We are the last thread running, so check if finalizers should be run. 3454 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 3455 HandleMark rm(thread); 3456 Universe::run_finalizers_on_exit(); 3457 } else { 3458 // run Java level shutdown hooks 3459 thread->invoke_shutdown_hooks(); 3460 } 3461 3462 before_exit(thread); 3463 3464 thread->exit(true); 3465 3466 // Stop VM thread. 3467 { 3468 // 4945125 The vm thread comes to a safepoint during exit. 3469 // GC vm_operations can get caught at the safepoint, and the 3470 // heap is unparseable if they are caught. Grab the Heap_lock 3471 // to prevent this. The GC vm_operations will not be able to 3472 // queue until after the vm thread is dead. 3473 MutexLocker ml(Heap_lock); 3474 3475 VMThread::wait_for_vm_thread_exit(); 3476 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 3477 VMThread::destroy(); 3478 } 3479 3480 // clean up ideal graph printers 3481 #if defined(COMPILER2) && !defined(PRODUCT) 3482 IdealGraphPrinter::clean_up(); 3483 #endif 3484 3485 // Now, all Java threads are gone except daemon threads. Daemon threads 3486 // running Java code or in VM are stopped by the Safepoint. However, 3487 // daemon threads executing native code are still running. But they 3488 // will be stopped at native=>Java/VM barriers. Note that we can't 3489 // simply kill or suspend them, as it is inherently deadlock-prone. 3490 3491 #ifndef PRODUCT 3492 // disable function tracing at JNI/JVM barriers 3493 TraceHPI = false; 3494 TraceJNICalls = false; 3495 TraceJVMCalls = false; 3496 TraceRuntimeCalls = false; 3497 #endif 3498 3499 VM_Exit::set_vm_exited(); 3500 3501 notify_vm_shutdown(); 3502 3503 delete thread; 3504 3505 // exit_globals() will delete tty 3506 exit_globals(); 3507 3508 return true; 3509 } 3510 3511 3512 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 3513 if (version == JNI_VERSION_1_1) return JNI_TRUE; 3514 return is_supported_jni_version(version); 3515 } 3516 3517 3518 jboolean Threads::is_supported_jni_version(jint version) { 3519 if (version == JNI_VERSION_1_2) return JNI_TRUE; 3520 if (version == JNI_VERSION_1_4) return JNI_TRUE; 3521 if (version == JNI_VERSION_1_6) return JNI_TRUE; 3522 return JNI_FALSE; 3523 } 3524 3525 3526 void Threads::add(JavaThread* p, bool force_daemon) { 3527 // The threads lock must be owned at this point 3528 assert_locked_or_safepoint(Threads_lock); 3529 p->set_next(_thread_list); 3530 _thread_list = p; 3531 _number_of_threads++; 3532 oop threadObj = p->threadObj(); 3533 bool daemon = true; 3534 // Bootstrapping problem: threadObj can be null for initial 3535 // JavaThread (or for threads attached via JNI) 3536 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 3537 _number_of_non_daemon_threads++; 3538 daemon = false; 3539 } 3540 3541 ThreadService::add_thread(p, daemon); 3542 3543 // Possible GC point. 3544 Events::log("Thread added: " INTPTR_FORMAT, p); 3545 } 3546 3547 void Threads::remove(JavaThread* p) { 3548 // Extra scope needed for Thread_lock, so we can check 3549 // that we do not remove thread without safepoint code notice 3550 { MutexLocker ml(Threads_lock); 3551 3552 assert(includes(p), "p must be present"); 3553 3554 JavaThread* current = _thread_list; 3555 JavaThread* prev = NULL; 3556 3557 while (current != p) { 3558 prev = current; 3559 current = current->next(); 3560 } 3561 3562 if (prev) { 3563 prev->set_next(current->next()); 3564 } else { 3565 _thread_list = p->next(); 3566 } 3567 _number_of_threads--; 3568 oop threadObj = p->threadObj(); 3569 bool daemon = true; 3570 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 3571 _number_of_non_daemon_threads--; 3572 daemon = false; 3573 3574 // Only one thread left, do a notify on the Threads_lock so a thread waiting 3575 // on destroy_vm will wake up. 3576 if (number_of_non_daemon_threads() == 1) 3577 Threads_lock->notify_all(); 3578 } 3579 ThreadService::remove_thread(p, daemon); 3580 3581 // Make sure that safepoint code disregard this thread. This is needed since 3582 // the thread might mess around with locks after this point. This can cause it 3583 // to do callbacks into the safepoint code. However, the safepoint code is not aware 3584 // of this thread since it is removed from the queue. 3585 p->set_terminated_value(); 3586 } // unlock Threads_lock 3587 3588 // Since Events::log uses a lock, we grab it outside the Threads_lock 3589 Events::log("Thread exited: " INTPTR_FORMAT, p); 3590 } 3591 3592 // Threads_lock must be held when this is called (or must be called during a safepoint) 3593 bool Threads::includes(JavaThread* p) { 3594 assert(Threads_lock->is_locked(), "sanity check"); 3595 ALL_JAVA_THREADS(q) { 3596 if (q == p ) { 3597 return true; 3598 } 3599 } 3600 return false; 3601 } 3602 3603 // Operations on the Threads list for GC. These are not explicitly locked, 3604 // but the garbage collector must provide a safe context for them to run. 3605 // In particular, these things should never be called when the Threads_lock 3606 // is held by some other thread. (Note: the Safepoint abstraction also 3607 // uses the Threads_lock to gurantee this property. It also makes sure that 3608 // all threads gets blocked when exiting or starting). 3609 3610 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) { 3611 ALL_JAVA_THREADS(p) { 3612 p->oops_do(f, cf); 3613 } 3614 VMThread::vm_thread()->oops_do(f, cf); 3615 } 3616 3617 void Threads::possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf) { 3618 // Introduce a mechanism allowing parallel threads to claim threads as 3619 // root groups. Overhead should be small enough to use all the time, 3620 // even in sequential code. 3621 SharedHeap* sh = SharedHeap::heap(); 3622 bool is_par = (sh->n_par_threads() > 0); 3623 int cp = SharedHeap::heap()->strong_roots_parity(); 3624 ALL_JAVA_THREADS(p) { 3625 if (p->claim_oops_do(is_par, cp)) { 3626 p->oops_do(f, cf); 3627 } 3628 } 3629 VMThread* vmt = VMThread::vm_thread(); 3630 if (vmt->claim_oops_do(is_par, cp)) 3631 vmt->oops_do(f, cf); 3632 } 3633 3634 #ifndef SERIALGC 3635 // Used by ParallelScavenge 3636 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 3637 ALL_JAVA_THREADS(p) { 3638 q->enqueue(new ThreadRootsTask(p)); 3639 } 3640 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 3641 } 3642 3643 // Used by Parallel Old 3644 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 3645 ALL_JAVA_THREADS(p) { 3646 q->enqueue(new ThreadRootsMarkingTask(p)); 3647 } 3648 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 3649 } 3650 #endif // SERIALGC 3651 3652 void Threads::nmethods_do(CodeBlobClosure* cf) { 3653 ALL_JAVA_THREADS(p) { 3654 p->nmethods_do(cf); 3655 } 3656 VMThread::vm_thread()->nmethods_do(cf); 3657 } 3658 3659 void Threads::gc_epilogue() { 3660 ALL_JAVA_THREADS(p) { 3661 p->gc_epilogue(); 3662 } 3663 } 3664 3665 void Threads::gc_prologue() { 3666 ALL_JAVA_THREADS(p) { 3667 p->gc_prologue(); 3668 } 3669 } 3670 3671 void Threads::deoptimized_wrt_marked_nmethods() { 3672 ALL_JAVA_THREADS(p) { 3673 p->deoptimized_wrt_marked_nmethods(); 3674 } 3675 } 3676 3677 3678 // Get count Java threads that are waiting to enter the specified monitor. 3679 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 3680 address monitor, bool doLock) { 3681 assert(doLock || SafepointSynchronize::is_at_safepoint(), 3682 "must grab Threads_lock or be at safepoint"); 3683 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 3684 3685 int i = 0; 3686 { 3687 MutexLockerEx ml(doLock ? Threads_lock : NULL); 3688 ALL_JAVA_THREADS(p) { 3689 if (p->is_Compiler_thread()) continue; 3690 3691 address pending = (address)p->current_pending_monitor(); 3692 if (pending == monitor) { // found a match 3693 if (i < count) result->append(p); // save the first count matches 3694 i++; 3695 } 3696 } 3697 } 3698 return result; 3699 } 3700 3701 3702 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 3703 assert(doLock || 3704 Threads_lock->owned_by_self() || 3705 SafepointSynchronize::is_at_safepoint(), 3706 "must grab Threads_lock or be at safepoint"); 3707 3708 // NULL owner means not locked so we can skip the search 3709 if (owner == NULL) return NULL; 3710 3711 { 3712 MutexLockerEx ml(doLock ? Threads_lock : NULL); 3713 ALL_JAVA_THREADS(p) { 3714 // first, see if owner is the address of a Java thread 3715 if (owner == (address)p) return p; 3716 } 3717 } 3718 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled"); 3719 if (UseHeavyMonitors) return NULL; 3720 3721 // 3722 // If we didn't find a matching Java thread and we didn't force use of 3723 // heavyweight monitors, then the owner is the stack address of the 3724 // Lock Word in the owning Java thread's stack. 3725 // 3726 JavaThread* the_owner = NULL; 3727 { 3728 MutexLockerEx ml(doLock ? Threads_lock : NULL); 3729 ALL_JAVA_THREADS(q) { 3730 if (q->is_lock_owned(owner)) { 3731 the_owner = q; 3732 break; 3733 } 3734 } 3735 } 3736 assert(the_owner != NULL, "Did not find owning Java thread for lock word address"); 3737 return the_owner; 3738 } 3739 3740 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 3741 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 3742 char buf[32]; 3743 st->print_cr(os::local_time_string(buf, sizeof(buf))); 3744 3745 st->print_cr("Full thread dump %s (%s %s):", 3746 Abstract_VM_Version::vm_name(), 3747 Abstract_VM_Version::vm_release(), 3748 Abstract_VM_Version::vm_info_string() 3749 ); 3750 st->cr(); 3751 3752 #ifndef SERIALGC 3753 // Dump concurrent locks 3754 ConcurrentLocksDump concurrent_locks; 3755 if (print_concurrent_locks) { 3756 concurrent_locks.dump_at_safepoint(); 3757 } 3758 #endif // SERIALGC 3759 3760 ALL_JAVA_THREADS(p) { 3761 ResourceMark rm; 3762 p->print_on(st); 3763 if (print_stacks) { 3764 if (internal_format) { 3765 p->trace_stack(); 3766 } else { 3767 p->print_stack_on(st); 3768 } 3769 } 3770 st->cr(); 3771 #ifndef SERIALGC 3772 if (print_concurrent_locks) { 3773 concurrent_locks.print_locks_on(p, st); 3774 } 3775 #endif // SERIALGC 3776 } 3777 3778 VMThread::vm_thread()->print_on(st); 3779 st->cr(); 3780 Universe::heap()->print_gc_threads_on(st); 3781 WatcherThread* wt = WatcherThread::watcher_thread(); 3782 if (wt != NULL) wt->print_on(st); 3783 st->cr(); 3784 CompileBroker::print_compiler_threads_on(st); 3785 st->flush(); 3786 } 3787 3788 // Threads::print_on_error() is called by fatal error handler. It's possible 3789 // that VM is not at safepoint and/or current thread is inside signal handler. 3790 // Don't print stack trace, as the stack may not be walkable. Don't allocate 3791 // memory (even in resource area), it might deadlock the error handler. 3792 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 3793 bool found_current = false; 3794 st->print_cr("Java Threads: ( => current thread )"); 3795 ALL_JAVA_THREADS(thread) { 3796 bool is_current = (current == thread); 3797 found_current = found_current || is_current; 3798 3799 st->print("%s", is_current ? "=>" : " "); 3800 3801 st->print(PTR_FORMAT, thread); 3802 st->print(" "); 3803 thread->print_on_error(st, buf, buflen); 3804 st->cr(); 3805 } 3806 st->cr(); 3807 3808 st->print_cr("Other Threads:"); 3809 if (VMThread::vm_thread()) { 3810 bool is_current = (current == VMThread::vm_thread()); 3811 found_current = found_current || is_current; 3812 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 3813 3814 st->print(PTR_FORMAT, VMThread::vm_thread()); 3815 st->print(" "); 3816 VMThread::vm_thread()->print_on_error(st, buf, buflen); 3817 st->cr(); 3818 } 3819 WatcherThread* wt = WatcherThread::watcher_thread(); 3820 if (wt != NULL) { 3821 bool is_current = (current == wt); 3822 found_current = found_current || is_current; 3823 st->print("%s", is_current ? "=>" : " "); 3824 3825 st->print(PTR_FORMAT, wt); 3826 st->print(" "); 3827 wt->print_on_error(st, buf, buflen); 3828 st->cr(); 3829 } 3830 if (!found_current) { 3831 st->cr(); 3832 st->print("=>" PTR_FORMAT " (exited) ", current); 3833 current->print_on_error(st, buf, buflen); 3834 st->cr(); 3835 } 3836 } 3837 3838 3839 // Lifecycle management for TSM ParkEvents. 3840 // ParkEvents are type-stable (TSM). 3841 // In our particular implementation they happen to be immortal. 3842 // 3843 // We manage concurrency on the FreeList with a CAS-based 3844 // detach-modify-reattach idiom that avoids the ABA problems 3845 // that would otherwise be present in a simple CAS-based 3846 // push-pop implementation. (push-one and pop-all) 3847 // 3848 // Caveat: Allocate() and Release() may be called from threads 3849 // other than the thread associated with the Event! 3850 // If we need to call Allocate() when running as the thread in 3851 // question then look for the PD calls to initialize native TLS. 3852 // Native TLS (Win32/Linux/Solaris) can only be initialized or 3853 // accessed by the associated thread. 3854 // See also pd_initialize(). 3855 // 3856 // Note that we could defer associating a ParkEvent with a thread 3857 // until the 1st time the thread calls park(). unpark() calls to 3858 // an unprovisioned thread would be ignored. The first park() call 3859 // for a thread would allocate and associate a ParkEvent and return 3860 // immediately. 3861 3862 volatile int ParkEvent::ListLock = 0 ; 3863 ParkEvent * volatile ParkEvent::FreeList = NULL ; 3864 3865 ParkEvent * ParkEvent::Allocate (Thread * t) { 3866 // In rare cases -- JVM_RawMonitor* operations -- we can find t == null. 3867 ParkEvent * ev ; 3868 3869 // Start by trying to recycle an existing but unassociated 3870 // ParkEvent from the global free list. 3871 for (;;) { 3872 ev = FreeList ; 3873 if (ev == NULL) break ; 3874 // 1: Detach - sequester or privatize the list 3875 // Tantamount to ev = Swap (&FreeList, NULL) 3876 if (Atomic::cmpxchg_ptr (NULL, &FreeList, ev) != ev) { 3877 continue ; 3878 } 3879 3880 // We've detached the list. The list in-hand is now 3881 // local to this thread. This thread can operate on the 3882 // list without risk of interference from other threads. 3883 // 2: Extract -- pop the 1st element from the list. 3884 ParkEvent * List = ev->FreeNext ; 3885 if (List == NULL) break ; 3886 for (;;) { 3887 // 3: Try to reattach the residual list 3888 guarantee (List != NULL, "invariant") ; 3889 ParkEvent * Arv = (ParkEvent *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ; 3890 if (Arv == NULL) break ; 3891 3892 // New nodes arrived. Try to detach the recent arrivals. 3893 if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) { 3894 continue ; 3895 } 3896 guarantee (Arv != NULL, "invariant") ; 3897 // 4: Merge Arv into List 3898 ParkEvent * Tail = List ; 3899 while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ; 3900 Tail->FreeNext = Arv ; 3901 } 3902 break ; 3903 } 3904 3905 if (ev != NULL) { 3906 guarantee (ev->AssociatedWith == NULL, "invariant") ; 3907 } else { 3908 // Do this the hard way -- materialize a new ParkEvent. 3909 // In rare cases an allocating thread might detach a long list -- 3910 // installing null into FreeList -- and then stall or be obstructed. 3911 // A 2nd thread calling Allocate() would see FreeList == null. 3912 // The list held privately by the 1st thread is unavailable to the 2nd thread. 3913 // In that case the 2nd thread would have to materialize a new ParkEvent, 3914 // even though free ParkEvents existed in the system. In this case we end up 3915 // with more ParkEvents in circulation than we need, but the race is 3916 // rare and the outcome is benign. Ideally, the # of extant ParkEvents 3917 // is equal to the maximum # of threads that existed at any one time. 3918 // Because of the race mentioned above, segments of the freelist 3919 // can be transiently inaccessible. At worst we may end up with the 3920 // # of ParkEvents in circulation slightly above the ideal. 3921 // Note that if we didn't have the TSM/immortal constraint, then 3922 // when reattaching, above, we could trim the list. 3923 ev = new ParkEvent () ; 3924 guarantee ((intptr_t(ev) & 0xFF) == 0, "invariant") ; 3925 } 3926 ev->reset() ; // courtesy to caller 3927 ev->AssociatedWith = t ; // Associate ev with t 3928 ev->FreeNext = NULL ; 3929 return ev ; 3930 } 3931 3932 void ParkEvent::Release (ParkEvent * ev) { 3933 if (ev == NULL) return ; 3934 guarantee (ev->FreeNext == NULL , "invariant") ; 3935 ev->AssociatedWith = NULL ; 3936 for (;;) { 3937 // Push ev onto FreeList 3938 // The mechanism is "half" lock-free. 3939 ParkEvent * List = FreeList ; 3940 ev->FreeNext = List ; 3941 if (Atomic::cmpxchg_ptr (ev, &FreeList, List) == List) break ; 3942 } 3943 } 3944 3945 // Override operator new and delete so we can ensure that the 3946 // least significant byte of ParkEvent addresses is 0. 3947 // Beware that excessive address alignment is undesirable 3948 // as it can result in D$ index usage imbalance as 3949 // well as bank access imbalance on Niagara-like platforms, 3950 // although Niagara's hash function should help. 3951 3952 void * ParkEvent::operator new (size_t sz) { 3953 return (void *) ((intptr_t (CHeapObj::operator new (sz + 256)) + 256) & -256) ; 3954 } 3955 3956 void ParkEvent::operator delete (void * a) { 3957 // ParkEvents are type-stable and immortal ... 3958 ShouldNotReachHere(); 3959 } 3960 3961 3962 // 6399321 As a temporary measure we copied & modified the ParkEvent:: 3963 // allocate() and release() code for use by Parkers. The Parker:: forms 3964 // will eventually be removed as we consolide and shift over to ParkEvents 3965 // for both builtin synchronization and JSR166 operations. 3966 3967 volatile int Parker::ListLock = 0 ; 3968 Parker * volatile Parker::FreeList = NULL ; 3969 3970 Parker * Parker::Allocate (JavaThread * t) { 3971 guarantee (t != NULL, "invariant") ; 3972 Parker * p ; 3973 3974 // Start by trying to recycle an existing but unassociated 3975 // Parker from the global free list. 3976 for (;;) { 3977 p = FreeList ; 3978 if (p == NULL) break ; 3979 // 1: Detach 3980 // Tantamount to p = Swap (&FreeList, NULL) 3981 if (Atomic::cmpxchg_ptr (NULL, &FreeList, p) != p) { 3982 continue ; 3983 } 3984 3985 // We've detached the list. The list in-hand is now 3986 // local to this thread. This thread can operate on the 3987 // list without risk of interference from other threads. 3988 // 2: Extract -- pop the 1st element from the list. 3989 Parker * List = p->FreeNext ; 3990 if (List == NULL) break ; 3991 for (;;) { 3992 // 3: Try to reattach the residual list 3993 guarantee (List != NULL, "invariant") ; 3994 Parker * Arv = (Parker *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ; 3995 if (Arv == NULL) break ; 3996 3997 // New nodes arrived. Try to detach the recent arrivals. 3998 if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) { 3999 continue ; 4000 } 4001 guarantee (Arv != NULL, "invariant") ; 4002 // 4: Merge Arv into List 4003 Parker * Tail = List ; 4004 while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ; 4005 Tail->FreeNext = Arv ; 4006 } 4007 break ; 4008 } 4009 4010 if (p != NULL) { 4011 guarantee (p->AssociatedWith == NULL, "invariant") ; 4012 } else { 4013 // Do this the hard way -- materialize a new Parker.. 4014 // In rare cases an allocating thread might detach 4015 // a long list -- installing null into FreeList --and 4016 // then stall. Another thread calling Allocate() would see 4017 // FreeList == null and then invoke the ctor. In this case we 4018 // end up with more Parkers in circulation than we need, but 4019 // the race is rare and the outcome is benign. 4020 // Ideally, the # of extant Parkers is equal to the 4021 // maximum # of threads that existed at any one time. 4022 // Because of the race mentioned above, segments of the 4023 // freelist can be transiently inaccessible. At worst 4024 // we may end up with the # of Parkers in circulation 4025 // slightly above the ideal. 4026 p = new Parker() ; 4027 } 4028 p->AssociatedWith = t ; // Associate p with t 4029 p->FreeNext = NULL ; 4030 return p ; 4031 } 4032 4033 4034 void Parker::Release (Parker * p) { 4035 if (p == NULL) return ; 4036 guarantee (p->AssociatedWith != NULL, "invariant") ; 4037 guarantee (p->FreeNext == NULL , "invariant") ; 4038 p->AssociatedWith = NULL ; 4039 for (;;) { 4040 // Push p onto FreeList 4041 Parker * List = FreeList ; 4042 p->FreeNext = List ; 4043 if (Atomic::cmpxchg_ptr (p, &FreeList, List) == List) break ; 4044 } 4045 } 4046 4047 void Threads::verify() { 4048 ALL_JAVA_THREADS(p) { 4049 p->verify(); 4050 } 4051 VMThread* thread = VMThread::vm_thread(); 4052 if (thread != NULL) thread->verify(); 4053 }